RU2799370C2 - Improved pyrocleaning method - Google Patents

Abstract

FIELD: pyrometallurgy.

SUBSTANCE: invention relates to the production of non-ferrous metals using pyrometallurgy, in particular to the production of copper, namely the joint production of copper metal melt and solder melt from low-quality raw materials. The composition of black copper containing at least 50 wt.% of copper together with at least 1.0 wt.% of tin and at least 1.0 wt.% of lead, partially oxidized, forming the first copper-rich metal phase as a copper metal melt and the first copper refining slag, and separate them from each other. Next, the first copper refining slag is partially reduced, forming the first metal composition based on lead-tin as a solder melt and the first waste slag, and the first waste slag is separated from the first metal composition based on lead-tin, which forms the basis for the first liquid bath. In this case, the total content of the furnace at the stage of partial reduction contains such an amount of copper that is at least 1.5 times greater than the sum of Sn and Pb present, and the first spent slag contains at most 20 wt.% of copper, tin and lead in aggregate.

EFFECT: complex processing of low-quality raw materials is provided.

17 cl, 1 dwg, 24 tbl, 1 ex

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

The present invention relates to the production of non-ferrous metals using pyrometallurgy, in particular to the production of copper (Cu). More specifically, the present invention relates to an improved process for the co-production of copper and solder streams from primary and secondary feedstocks as base products for further upgrading to commercially desired purity metal products. Solder fluxes are often metal compositions or alloys that contain a significant amount of tin (Sn), usually, but not necessarily, together with lead (Pb).

BACKGROUND OF THE INVENTION

Non-ferrous metals can be produced from fresh ores as raw materials, also called primary sources, or from recycled materials, also known as recycled materials, or a combination of both. Recyclable materials can be, for example, by-products, waste and used materials. In recent years, the recovery of non-ferrous metals from recycled feedstock has become of paramount importance. Recycling of non-ferrous metals after their use has become a key factor in the industry due to the continued high demand for such metals and the reduced availability of high-quality fresh metal ores. In particular, for the production of copper, its extraction from secondary raw materials has become of great industrial importance. In addition to this, the declining availability of high quality fresh metal ores has also increased the importance of extracting base metals from low quality metal feedstocks. Low quality metal ores for copper recovery may contain, for example, significant amounts of other non-ferrous metals. These other metals may themselves have significant potential commercial value, such as tin and/or lead, but these primary and secondary feedstocks may contain other metals of lower or no economic value, such as zinc, bismuth, antimony, arsenic. or nickel. Often these other metals are undesirable in non-ferrous staples, or may only be acceptable in very limited quantities.

Materials available as feedstock for copper production thus typically contain a variety of metals. Secondary raw materials with a high copper content are, for example, bronze, mainly an alloy of copper and tin, and brass, an alloy of mainly copper and zinc.

These various metals must be separated from the copper in the manufacturing process. The feedstock may further include small amounts of various other elements including iron, bismuth, antimony, arsenic, aluminium, manganese, sulfur, phosphorus and silicon, most of which have limited acceptability in the main metal product.

Recycled raw materials containing copper may also be used electronic and/or electrical parts. This feedstock usually contains solder components in addition to copper, mainly tin and lead, but usually also contains other metals such as iron and aluminum, plus sometimes minor amounts of precious metals, as well as non-metal parts such as plastics, paint, rubber. , glue, wood, paper, cardboard, etc. This feedstock is usually contaminated, and thus usually also contains additional impurities such as dirt, grease, wax, earth and/or sand. The metals in such feedstocks are often also partially oxidized.

Since feedstocks having lower purity and higher impurity content, both primary and secondary, are much more readily available, there is a need to expand the ability of non-ferrous metal production processes to process such low-quality raw materials as part of the feedstock to recover or produce non-ferrous metals. such as copper.

Methods for the production of non-ferrous metals usually contain at least one and usually a plurality of pyrometallurgical process steps. The most common first pyrometallurgical step for recovering copper from low quality recycled materials is the smelting step. In a smelting furnace, metals are melted, and organics and other combustible materials are burned. In addition to this, various chemical reactions take place between several other components that are introduced into the melting furnace. Metals having a relatively high affinity for oxygen are converted to their oxides and collected in the low density floating slag phase. The more volatile metals may pass from the liquid to the gas phase and leave the furnace with the flue gases, along with any oxides of carbon and/or SO ₂ that may be formed. Metals having a lower affinity for oxygen, if present in an oxidized state, are easily reduced to their elemental metallic form and migrate to the heavier and underlying metallic phase. If they do not oxidize, then these metals remain as elemental metal in the higher density liquid metal phase at the bottom of the smelter. In the copper production step, the smelting step can be carried out in such a way that most of the iron ends up in the slag, while the copper, tin and lead end up in the metal product, a stream commonly referred to as "black copper". Also, most nickel, antimony, arsenic and bismuth usually become part of the black copper product.

Patent document DE 102012005401 A1 describes a process for the production of copper from secondary raw materials, starting from the step of melting the raw materials. The melting step is described as giving a slag phase containing copper, tin, lead and nickel. This slag is transferred to a rotary drum furnace for further processing. This further processing consists of a series of successive partial chemical reduction steps using carbon as a reducing agent to successively recover specific metal products that are separated and removed from the furnace each time. The first "preliminary" stage ("Vorstufe"), performed on this smelter slag, recovers the copper product for processing in an anode furnace ("A-metall"). In order to obtain sufficiently high quality copper, most of the tin and lead, along with a significant amount of copper, must remain in the slag. The slag from the Vorstufe stage is processed in the subsequent stage 1 to produce a black copper product which is then granulated along with the other remaining slag phase. Step 2 produces a crude mixed tin product from this slag phase, which is subsequently pre-purified using silicon metal to produce a mixed tin product and a silicon residue. The last stage gives the final slag, also for granulation. A problem with the method described in DE 102012005401 A1 is that metals having a high affinity for oxygen under process conditions must go through all successive process steps and thus take up valuable furnace space.

Gerardo Alvear Flores et al, "ISASMELT™ for the Recycling of E-scrap and Copper in the US Case Study Example of a New Compact Recycling Plant", in Journal of Metals, Springer New York LLC, USA, vol. 66, no.5, 18 March 2014, pp. 823-832, ISSN: 1047-4838, discloses a process for recovering copper from recycled feedstock using a submerged lance furnace, which is typical of the ISASMELT™ technology. This document also provides for the production of a Pb-Sn alloy by-product when such metals are sufficiently present in the process. This document discloses the content of copper in a limited number of metal compositions processed in this way, but no other information about the compositions is given.

US 4,073,646 discloses a process for the thermal refining of contaminated copper in the molten phase, in which immiscible molten phases are formed in a treatment vessel, of which the lower one is copper-containing material and the upper one contains slag, and reactive gases are simultaneously introduced into each of these molten phases. . An oxidizing reaction phase is introduced into the lower reaction phase, and a reducing reaction medium is introduced into the upper reaction phase. These conditions in the furnace limit excessive oxidation of the copper because it is largely reduced back to the metal in the slag. After this single process step, purified anode grade copper and converter slag are discharged from the furnace. Patent document US 4073646 says nothing about the further processing of converter slag or converter dust.

US Patent Document US 3,682,623 and its counterpart AU 505015 B2, a process for refining copper starting with a melting step resulting in a black copper stream followed by further pyrometallurgical refining of this black copper to an anode copper stream suitable for casting into anodes for electrolytic refining. The refining of black copper in US 3,682,623 forms a series of successive copper refining slags: top slags rich in zinc, middle slags rich in lead and tin, and end slags rich in copper. Various refining slags are collected and transferred as a single intermediate stream to a slag processing furnace to recover the copper, lead and tin contained in these slags.

The reprocessing of accumulated copper refining slags in US 3,682,623 consists of a sequence of two metal reduction steps offering pyrometallurgical separation of lead and tin from copper and nickel contained in copper refining slags. The first stage or stage is directed to the selective recovery of copper from slags. A sufficient amount of metallic iron is introduced with the accumulated refining slags to reduce copper oxides to metallic copper. After the reaction, the metal phase in the furnace is discharged from below, leaving an extracted slag containing most of the lead and tin from the refining slags. The copper-containing metal phase discharged from below is returned to the copper refining furnace as black copper. The second stage of slag reprocessing aims to recover lead, tin and residual copper in the slag that remains after black copper is tapped from the bottom of the slag reprocessing furnace. This recovery is obtained by adding scrap iron. When this reduction of lead and tin is completed, the resulting slag is poured as waste slag and the lead/tin metal is poured for further processing. Most of the nickel leaves the process of US Pat. No. 3,682,623 as an impurity in the anode copper. It appears that the amount of nickel present in the process of US Pat. No. 3,682,623 increases over time because 630 kg of nickel were processed with the Table XIV metal while only 500 kg were present in the processed Table VI black copper.

A problem with the method of US 3,682,623 is that prior to each slag separation step, some silica flux, usually sand, is added to the furnace. In four stages of copper refining, a total of 10,000 kg of silica flux or sand is added. This flux material ends up in the slag phase removed from the copper refining furnace each time, and therefore all of it is collected in the accumulated copper refining slag transferred to the slag reprocessing furnace. In the selective copper reduction step, this flux material is the diluent for the slag phase. Therefore, the amount of slag remaining after tapping the black copper from the bottom of the slag re-treatment furnace is quite high in relation to the amount of recovered black copper. Consequently, the recovery of copper in this selective copper reduction step is rather limited. 29500 kg of slag in Table XIV still contain 3 wt. % copper. This amounts to 885 kg of copper, which is more than 9.0% of the 9767.8 kg of copper present in the furnace at this stage. Most of this copper is recovered in the lead/tin metal in the next slag reworking step, which contains 13.54 wt. % copper (947.5 kg). The recovery of copper in the selective copper reduction step of US Pat. No. 3,682,623 is thus less than 91%. More than 9% remains in the slag, representing not only a loss of valuable metal, but also a serious burden for the subsequent processing of solder into higher purity tin and lead.

In the second stage of reprocessing the slag of US 3682623, only 7000 kg of lead/tin metal, i.e. solder product, are obtained, together with a very large amount of waste slag, i.e. 26900 kg, and this is for 43952 kg of copper entering the first stage of refining copper (total copper in Table VI). This waste slag actually collects all of the flux material along with the oxides of iron, aluminum and other metals having a high affinity for oxygen that were introduced into the process to re-treat the slag. The amount of diluent material that has to go through two reduction steps when reprocessing the slag of US Pat. (fresh black copper in Table VI). In US 3,682,623, the production of solder per cycle in this way is quite low relative to the amount of copper processed, and there is also a relatively large amount of inactive diluting slag material that must pass through the slag reworking furnace, where it occupies the volume of the furnace, reduces copper recovery by the selective copper recovery step causes additional loss of copper with the solder product and represents a burden for its subsequent processing into higher purity lead and tin metal products.

These problems will only increase if the smelter accepts lower quality raw materials in terms of copper content, but with a higher content of other non-ferrous metals such as nickel, tin, lead, antimony, zinc, chromium, bismuth, manganese, vanadium, titanium or arsenic, or metals and elements having an even higher affinity for oxygen, such as iron, aluminium, silicon, phosphorus, sulfur, calcium, sodium or potassium.

Therefore, there continues to be a need for a process for recovering tin and/or lead along with copper from such low quality raw materials, primary and/or secondary. Preferably, this method should be more efficient in terms of oven volume utilization.

The present invention aims to eliminate or at least mitigate the problem described above and/or provide improvements.

SUMMARY OF THE INVENTION

In accordance with the present invention, a method is provided as defined in the appended claims.

The present invention provides a method for producing a first lead-tin metal composition comprising the following steps:

a) providing a composition of black copper containing at least 50 wt. % copper together with at least 1.0 wt. % tin and at least 1.0 wt. % lead

b) partially oxidizing the black copper composition, thereby forming a first copper-rich metal phase and a first copper refining slag, followed by separating the first copper refining slag from the first copper-rich metal phase,

c) partially reducing the first copper refining slag, thereby forming a first lead-tin metal composition and a first spent slag, followed by separating the first spent slag from the first lead-tin metal composition forming the basis for the first liquid bath,

whereby the total feed for step c) contains an amount of copper that is at least 1.5 times greater than the sum of Sn and Pb present, and

whereby the first spent slag contains at most 20 wt. % dry weight of copper, tin and lead combined.

Step b) of the process according to the present invention is an oxidation step. The copper content of the metal phase in the furnace in step b) is further increased from its original level in black copper by oxidizing some of the metals present and other elements that have a higher affinity for oxygen than copper. Most of the oxides of these elements are then recovered and separated with the first copper refining slag. This separation leaves as a metal phase a first copper-rich metal phase suitable for further processing. Because tin and lead have a higher oxygen affinity than copper in the furnace environment at existing furnace temperatures, the first copper refining slag contains oxides of some of the tin and lead contained in the first stage feed. Because the chemical reactions and physical separations in pyrometallurgy are never complete and/or perfect, the first copper refining slag also typically contains a significant amount of the copper present in the first stage, usually some of it as copper oxide.

Step c) of the method according to the present invention is a recovery step. Its purpose is to selectively reduce those metals which, under process conditions, have a lower affinity for oxygen to their respective metals. These reduced metals can then be separated as a liquid metal phase, leaving a liquid slag phase that has a lower concentration of these metals but still contains metals and elements that have a higher affinity for oxygen. In the context of the present invention, the purpose of the second step is to selectively recover most of the copper from the first copper refining slag as metal, along with as much tin and/or lead as possible. Recovery in stage c) is thus carried out in such a way that the first waste slag contains at most 20 wt. % copper, tin and lead in total. Preferably, the first spent slag contains less than 20 wt. % copper, tin and lead in total, more preferably even much less. It is highly preferred that the amount of copper, tin and/or lead in this slag is sufficiently low that they no longer represent any economic value. Most preferably, the concentrations of copper, tin and/or lead are low enough that the first spent slag does not cause environmental problems at all when disposed of, or can be disposed of after limited post-treatment.

In the process described in US Pat. No. 4,073,646, at the start of the blowing operation, the zinc present in the slag is predominantly reduced and volatilized. Then most of the proportion of tin volatilizes as SnO while preventing the oxidation of SnO to SnO ₂ . After that, the blast atmosphere is almost neutrally controlled so that lead is oxidized to PbO during its partial evaporation. Approximately one third of the amount of lead, tin and zinc contained in the feed is recovered with converter dust, and only 1.4% remains in the purified converter copper. Converter slag should therefore contain 22.5 wt. % lead, tin and zinc together. The balance of copper suggests that the slag must additionally contain at least 35.2 wt. % copper. Discarding all the zinc contained in the feed suggests that the slag must contain at least 41.9% copper, tin and lead together. The method of US 4,073,646 purifies contaminated copper to anode grade copper. Almost all other metals end up in converter dust, and more importantly, in converter slag. Converter slag contains in addition to 35.2 wt. % copper at least 6.75 and at most 18.3 wt. % tin and lead together, resulting in the total amount of copper, tin and lead in this slag is at least more than 40 wt. %. This document also does not say anything about how this converter slag should be further processed. Thus, it is not proposed to reduce this slag to such a level that a final slag with such a low total content of copper, tin and lead, as indicated in the claims, could be obtained.

The authors found that the lower limit defined for the copper content relative to the Sn+Pb content in the total feed for stage c) has the advantage that a better extraction of Sn and Pb from the slag phase is obtained, without introducing a significant amount of copper into the slag phase. The authors found that the high presence of copper in the feed for stage c) affects the balance of tin and lead between the slag and metal phases at the end of stage c), promoting the movement of these solder metals from the slag phase to the metal phase. The authors have found that this effect can be achieved without increasing the concentration of copper in the spent slag obtained in step c) to economically viable and possibly unacceptable levels. The authors found that a large amount of copper in the feed for stage c) allows you to get in stage c) waste slag, which contains only low concentrations of tin and/or lead, as well as copper. This has the advantage that the spent slag from step c) requires less, if any, further processing for its safe disposal or for use in a suitable downstream application.

The inventors have found that a given amount of copper relative to the amount of solder metals, i.e. Sn+Pb, has the advantage that there is sufficient copper as a solvent to extract the solder metals from the slag phase into the first lead-tin metal composition, and therefore , improves the recovery of valuable tin and/or lead from the slag in step c). The authors found that this advantage can be obtained without unacceptable loss of valuable copper in the slag phase, which is formed in stage c).

The inventors have found that the present invention, in particular due to the minimal presence of copper relative to the amount of solder metals Pb+Sn in the feed for step c), gives the advantage of a higher recovery of the valuable metals tin, lead, and according to the circumstances also copper and possibly nickel, in product streams in which their presence is desired. It also reduces the burden created by the presence of these metals in product streams where they are undesirable.

In the first waste slag of the process according to the present invention, most of the elements are recovered which, under the conditions of the process, have a higher affinity for oxygen than tin and/or lead. This is especially true for metals such as iron, aluminium, sodium, potassium, calcium and other alkali and alkaline earth metals, but also for other elements such as silicon or phosphorus.

The inventors have found that the process according to the present invention produces a first lead-tin metal composition which is very suitable for further processing, in particular for the production of a rough solder metal composition which may be of commercial value in itself and/or may be suitable for the recovery of tin and/or lead products of higher and commercially acceptable purity.

The inventors have surprisingly found that in step c) of the method according to the present invention, a fairly clear separation of the valuable metals copper, nickel, tin and lead in the metal phase, and less valuable metals such as iron and aluminum, as well as other elements such as like silicon in the slag phase. This allows a very high recovery of valuable metals to be achieved while producing a slag phase which has a very low content of these metals and can therefore be disposed of either immediately or with relatively little further processing. The authors believe that this clear separation is possible because the presence of copper in step c) as part of the total furnace content is within a specific concentration range. On the one hand, copper acts as an extractant to extract tin and lead from the slag phase. On the other hand, the copper content is low enough so that the loss of copper in the slag phase is very limited.

Another important advantage is that the process according to the present invention becomes much more tolerant of elements other than copper, most of which are elements which, under process conditions, have a higher oxygen affinity than copper, tin and lead, and hence become part of the first spent slag. This greatly expands the acceptance criteria for any raw material that may be additionally fed to stage b), i.e. beyond black copper. In addition, it also significantly weakens the acceptance criteria for black copper itself. This feature thus greatly expands the acceptance criteria for raw materials that are used in the production of black copper, usually in the smelting stage. The smelting stage can therefore accept much lower quality raw materials that are much more readily available at economically more attractive terms.

Another advantage is due to the fact that in stage b) the volume of slag is high relative to the total contents of the furnace. Removing the slag from the furnace in this way frees up a significant portion of the furnace volume so that further processing of the first copper-rich metal phase, which is usually carried out in the same furnace, creates additional space for the introduction of additional raw materials.

The inventors have found that this post-treatment of the first lead-tin metal composition can be carried out much more efficiently by first removing from the process, as part of the first waste slag, at least a significant portion of the metals and elements having a high affinity for oxygen under process conditions. The inventors have found that this feature of the process provides significant benefits after step b) in processing the first lead-tin metal composition.

One important advantage is that the volume of material processed downstream is significantly reduced by removing in step c) a significant amount of material in the form of a first waste slag, i.e. before recovery of the solder metals (Sn and/or Pb). In subsequent stages, this material would be dead weight and would bring losses, not profits. In the process of the present invention, the further processing of the first lead-tin metal composition can be performed much more volume-efficiently, which means that either smaller equipment can be used, or the process of the present invention allows additional streams to be processed. compared to known methods. In addition to this, energy consumption can also be reduced in these subsequent process steps due to the reduced volume of hot material being processed.

The inventors have also surprisingly found that by removing the first waste slag from the process according to the present invention, the separation in the downstream pyrometallurgical stages of the process, for example for processing the first lead-tin metal composition, is also greatly improved. Due to a clearer separation between the respective metal phases and their respective slag phases, the subsequent recovery of valuable metals can be carried out more efficiently, i.e. with higher yields of the main products, lower waste of valuable metals, and also with less energy demand, for example due to smaller volumes of recirculating streams.

An additional advantage of the method according to the present invention is that further processing of the first lead-tin metal composition can introduce additional materials due to the additional space in the furnace by removing a large volume of the first waste slag from the method according to the present invention. Such additional materials may, for example, contain large amounts of tin and/or lead. Such additional materials may, for example, be slags and/or drosses obtained as by-products from subsequent purification steps as part of the further purification of tin and/or lead streams to commercially valuable main products.

Another and important advantage of the method according to the present invention is that it provides a much higher amount of rough solder by-product for the same amount of copper processed. The authors found that the co-production of rough solder relative to the amount of copper processed in the first stage of copper refining, can be increased by approximately 29% compared to the amount obtained in the method described in patent document US 3682623. The economic value of rough solder, in particular as possible intermediate product for the production of high-purity tin is very significant relative to the value of the main anode copper product, which can be obtained from black copper. Therefore, increasing the relative amount of rough solder by-product relative to the amount of copper that is processed in the first stage of copper refining provides a significant economic benefit to the operator of the method in accordance with the present invention.

The inventors have also found that it is advantageous for step c) to receive only the first copper refining slag and that subsequent copper refining slags are better handled separately and preferably each in their own way. The inventors found that the first copper refining slag is a copper refining slag containing the largest total amount of elements other than copper, and in particular elements having, under furnace operating conditions, a higher oxygen affinity than copper, more specifically an oxygen affinity that is higher than also that of tin and lead. The inventors have therefore surprisingly found that it is most efficient to carry out step c) on the first copper refining slag, ie before mixing with any of the other copper refining slags that are produced in the process steps after step b). The Applicants have found that subsequent copper refining slags generally contain higher concentrations of copper, and therefore the Applicants prefer to process these subsequent copper refining slags in a manner different from the first copper refining slag.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a flowchart of the process in accordance with the present invention, starting with the black copper composition provided by the preceding melting step, which results in the production of at least one copper product suitable for casting anodes and at least one rough solder product.

DETAILED DESCRIPTION

The present invention will be further described in terms of specific embodiments, with possible reference to specific drawings, but the present invention is not limited to this, but only by the claims. The drawings described are schematic and non-limiting. In the drawings, some of the elements may be exaggerated and not to scale for illustrative purposes. The sizes and relative sizes on them do not necessarily correspond to the actual ones.

In addition, the terms "first", "second", "third", etc. in the description and in the claims are used to distinguish between like elements, and not necessarily to describe sequential or chronological order. These terms are interchangeable under appropriate circumstances, and embodiments of the present invention may operate in other sequences than those described and/or illustrated herein.

In addition, the terms "top", "bottom", "above", "under", etc. in the description and in the claims are used for descriptive purposes and not necessarily to describe relative positions. These terms are interchangeable under appropriate circumstances, and the embodiments of the present invention described herein may operate in other orientations than those described or illustrated herein.

The term "comprising" as used in the claims is not to be construed as being limited to the elements that are listed in context with it. It does not exclude the presence of other elements or steps. Thus, it is to be interpreted as defining the presence of the claimed features, integers, steps, or components as they are mentioned, but does not preclude the presence or addition of one or more of the other features, integers, steps, or components, or groups thereof. Thus, the scope of "an article containing means A and B" cannot be limited to an object that consists solely of means A and B. This only means that A and B are the only elements associated with the subject of the present invention. Accordingly, the terms "comprising" and "including" encompass the more restrictive terms "consisting essentially of" and "consisting of". Therefore, when the phrases "comprising" and "comprising" are replaced by "consisting of", these terms form the basis of preferred but narrowed embodiments, which are also offered as part of the content of this document in relation to the present invention.

Unless explicitly stated otherwise, all values given in this document include the end points of the specified ranges of values of the content of the components of the composition, expressed in wt. % of each ingredient.

Additionally, each compound used herein may be referred to interchangeably using its chemical formula, chemical name, abbreviation, etc.

As used herein, unless expressly stated otherwise, the compositions of the streams are by weight compositions based on the total dry weight of the composition.

In the context of the present invention, the term "at least partially" includes its endpoint "completely". With regard to the extent to which a particular oxidation or reduction step of the process is performed, partial efficiency is generally the preferred embodiment. With regard to adding or recirculating a process stream to a particular process step, the preferred embodiment is generally a point "totally" within the range that is encompassed by the term "at least partially".

In this document, unless expressly stated otherwise, the quantities of metals and oxides are expressed in accordance with common practice in pyrometallurgy. The presence of each metal is usually expressed in terms of its total presence, whether the metal is present in its elemental form (oxidation state = 0) or in any chemically bonded form, usually in its oxidized form (oxidation state > 0). For metals that can relatively easily be reduced to their elemental forms, and which can occur as molten metal in a pyrometallurgical process, it is quite common to express their presence in terms of their elemental metallic form, even when describing the composition of the slag in which most such metals can actually present in the oxidized form. Therefore, the composition of the slag in the present document determines the content of Fe, Zn, Pb, Cu, Sb, Bi as elemental metals. The less noble metals are more difficult to reduce under non-ferrous pyrometallurgical conditions, and occur mostly in their oxidized form. These metals are usually expressed as their most common oxide form. Therefore, the composition of the slag usually gives the content of Si, Ca, Al and Na, respectively expressed as SiO ₂ , CaO, Al ₂ O ₃ , Na ₂ O.

The authors found that the results of the chemical analysis of the metal phase are significantly more reliable than the results of the analysis of the slag phase. Wherever numbers are derived from the material balance of one or more process steps, the Authors prefer to base such calculations as much as possible on metal phase analysis and minimize the use of slag analysis. For example, we prefer to calculate the recovery of tin and/or lead in the first copper refining slag produced in step b), based on the amount of tin and/or lead in the combined feed for step b), which is no longer recoverable with the first copper-rich metal phase, obtained in step b), and not based on the concentration of tin and/or lead in the first copper refining slag.

In addition, the authors found that the analysis of the slag phase, which is subjected to further processing, can often be corrected by establishing a mass balance in the subsequent stage or stages of the process and back-calculation using the quantities of products obtained in the subsequent stage, in combination with the analysis of these products, and at least one of them is preferably a liquid metal product, giving much more reliable analytical results. Such back-calculation can be performed for several of the respective specific metals individually, and can allow reliable determination of the material balances of most of the individual process steps in accordance with the present invention. This back-calculation can also be useful for determining the composition of a liquid metal stream from which it can be very difficult to obtain a representative sample, such as a molten solder metal stream containing a large amount of lead along with tin.

The authors prefer to use X-ray Fluorescence (XRF) to analyze the metal phase in the context of the present invention. The authors prefer to take a sample of molten liquid metal for this analysis and use a Heraeus Electro Nite sampler for instant analytical purposes in copper refining, which allows you to quickly obtain a solid and cooled sample for further processing. The surface of the cold sample is suitably treated prior to analysis using the XRF probe. The XRF analytical technique, however, does not analyze the oxygen level in the sample. Therefore, if necessary, in order to ascertain the complete composition of the metal phase, including the oxygen content, the authors prefer to separately measure the oxygen content of the molten liquid metal present in the furnace, preferably using a disposable electrochemical sensor for batch processes in copper refining offered by Heraeus Electro Nite. The result of the metal phase analysis by XRF, as described above, can then be corrected, if desired, for the oxygen content obtained from the separate oxygen analysis. The compositions indicated in the Example of this document have not been adjusted to include their oxygen content.

The present invention primarily relates to the recovery of the target metals copper, nickel, tin and/or lead in the form of product streams suitable for obtaining high purity main metal products from them. The process according to the present invention comprises various process steps, and these process steps can be characterized as oxidation steps or as reduction steps. By such a characteristic, the authors mean the chemical reactions that these target metals can undergo. The reduction step thus implies that at least one of these target metals is reduced from at least one of its respective oxides to its elemental metallic form in order to transfer that metal from the slag phase to the metallic phase in the furnace. Such a reduction step is preferably supported by the addition of a reducing agent, as explained in several places in this document. Process steps 400, 600, 700, 900, 1000, and 1100 qualify as reducing steps. In the oxidation step, the main goal is to convert at least one of the target metals to at least one of its corresponding oxides in order to transfer that metal from the metal phase. into the slag phase in the furnace. The oxygen for such conversion in the context of the present invention may come from a variety of sources. The oxygen does not have to come from air or oxygen that can be blown into the liquid bath. Oxygen can also be supplied by introducing a slag phase which has been produced in another process step and in which oxygen is bound in the oxide of at least one other metal. The oxidation step in the context of the present invention can thus be carried out without any introduction of air or oxygen. Thus, process steps 100, 200, 300, 500, 800 and 1200 qualify as oxidative.

Among the target metals recovered by the present invention, Sn and Pb are considered to be "solder metals". These metals differ from other copper and/or nickel target metals because mixtures containing large amounts of these metals generally have a much lower melting point than mixtures containing large amounts of copper and/or nickel. Such compositions have already been used millennia ago to create a permanent bond between two pieces of metal by first melting this "solder", placing it in place and allowing it to solidify. Therefore, the solder must have a lower melting point than the metal of the parts it joins. In the context of the present invention, solder product or solder metal composition, two terms used interchangeably herein, means metal compositions in which the combination of solder metals, and thus the Pb+Sn content, constitutes the major part of the composition, i.e., at least 50 wt. %, and preferably at least 65 wt. %. The solder product may additionally contain minor levels of other target metals such as copper and/or nickel, as well as non-target metals such as Sb, As, Bi, Zn, Al and/or Fe, and/or elements such as Si. In the context of the present invention, since the process is aimed at producing a solder rough product and a copper product, it is expected that the raw solder product or the rough solder metal composition produced by the method in steps e) and/or n) will also contain a measurable amount of at least a measure of copper, at least as an unavoidable impurity.

In one embodiment of the process according to the invention, the recovery of tin in step b) as part of the first copper refining slag relative to the total amount of tin present in step b) is at least 20%, preferably at least 30%, more preferably at least 40.00%, even more preferably at least 45%, even more preferably at least 50%, even more preferably at least 55%, and even more preferably at least 57%. There is no need to define units for the % recovery of a particular element, because regardless of the choice of atomic or mass percent, the % recovery remains the same.

In one embodiment of the process according to the invention, the recovery of lead in step b) as part of the first copper refining slag relative to the total lead present in step b) is at least 20%, preferably at least 30.00%, more preferably at least 40%, even more preferably at least 45%, even more preferably at least 50%, even more preferably at least 55%, and even more preferably at least 60%.

The specified lower recovery limit for tin and/or lead in step b) present as part of the first copper refining slag offers the advantage that, already in the first black copper oxidation step, a significant amount of tin and/or lead present is removed, together with a significant amount of other elements, other than copper. This has the advantage that fewer impurities enter the steps performed downstream with the first copper rich metal phase. This means that subsequent process steps for the first copper-rich metal phase have to cope with less impurities as well as less volume filling of the first copper-rich metal phase. This generally means that more furnace volume is freed up in the subsequent processing steps of the first copper-rich metal phase, allowing for additional material to be introduced in these process steps, and hence allowing for increased production of the final copper product under the same furnace volume constraints. These advantages are related to the lower limit for tin recovery in step b) as well as the lower limit for lead recovery in step b) and the combination of the lower limit for tin recovery with the lower limit for lead recovery in step b). These effects are cumulative with respect to the two metals tin and lead, and together give an even improved effect relative to the sum of the two individual effects.

We have found that the desired recoveries in step b) can be obtained by controlling the presence of oxygen and/or oxygen donors in step b) so that it is within suitable limits, if necessary in conjunction with the controlled addition of oxygen scavengers and flux addition.

In one embodiment of the method in accordance with the present invention, the total nutrition for stage c) contains at least 29.0 wt. % copper, preferably at least 30.0 wt. %, more preferably at least 31.0 wt. %, even more preferably at least 32.0 wt. %, even more preferably at least 33.0 wt. %, even more preferably at least 34.0 wt. %, even more preferably at least 35.0 wt. %, even more preferably at least 36.0 wt. %, even more preferably at least 37.0 wt. %, and even more preferably at least 38.0 wt. % copper.

In one embodiment of the method according to the present invention, the total feed for step c) contains an amount of copper that is at least 1.6 times higher than the total amount of solder metals present, i.e. Sn+Pb, preferably at least 1 .7 times, even more preferably at least 1.8 times, even more preferably at least 1.9 times, even more preferably at least 2.0 times, and even more preferably at least 2, 1 times higher than the total amount of solder metals present.

We have found that the prescribed amount of copper has the advantage that there is sufficient copper as a solvent to extract the solder metals from the slag phase into the lead-tin first metal composition, which improves the recovery of valuable tin and/or lead from the slag in step c. ).

In one embodiment of the method in accordance with the present invention, the first spent slag contains at most 20.0 wt. % and even better at most 18 wt. % copper, tin and lead together, preferably at most 15 wt. %, more preferably at most 12 wt. %, even more preferably at most 9.0 wt. %, even more preferably at most 7.0 wt. %, even more preferably at most 5.0 wt. %, even more preferably at most 4.0 wt. %, even more preferably at most 3.0 wt. %, even more preferably at most 2.0 wt. %, even more preferably at most 1.5 wt. % and even more preferably at most 1.10 wt. % copper, tin and lead together.

In one embodiment of the method in accordance with the present invention, the first spent slag contains at most 7.0 wt. % copper, preferably at most 5.0 wt. %, more preferably at most 3.0 wt. %, even more preferably at most 2.0 wt. %, even more preferably at most 1.50 wt. %, even more preferably at most 1.00 wt. %, even more preferably at most 0.75 wt. %, even more preferably at most 0.60 wt. %, even more preferably at most 0.50 wt. %, and even more preferably at most 0.40 wt. % copper.

In one embodiment of the method in accordance with the present invention, the first spent slag contains at most 7.0 wt. % tin, preferably at most 5.0 wt. %, more preferably at most 3.0 wt. %, even more preferably at most 2.0 wt. %, even more preferably at most 1.50 wt. %, even more preferably at most 1.00 wt. %, even more preferably at most 0.75 wt. %, even more preferably at most 0.60 wt. %, even more preferably at most 0.50 wt. %, even more preferably at most 0.40 wt. %, and even more preferably at most 0.30 wt. % tin.

In one embodiment of the method in accordance with the present invention, the first spent slag contains at most 7.0 wt. % lead, preferably at most 5.0 wt. %, more preferably at most 3.0 wt. %, even more preferably at most 2.0 wt. %, even more preferably at most 1.50 wt. %, even more preferably at most 1.00 wt. %, even more preferably at most 0.75 wt. %, even more preferably at most 0.60 wt. %, even more preferably at most 0.50 wt. %, and even more preferably at most 0.40 wt. % lead.

Of these upper limits for the presence of copper, tin, lead and these three metals together in the first waste slag, each individually has the advantage that the economic value of the amount of the three target metals leaving the process with the first waste slag in step c) remains limited. This reduces the need or desire to provide additional process steps for the first spent slag before it can be disposed of, and thus has the advantage that fewer or no further processing steps are needed before the first spent slag can be disposed of. or before that slag is considered acceptable in an economically more attractive application or end use.

In the first waste slag of the process according to the present invention, most of the elements are recovered which, under the process conditions, have a higher affinity for oxygen than tin and/or lead and/or copper and/or nickel. This is especially true for metals such as zinc, chromium, manganese, vanadium, titanium, iron, aluminium, sodium, potassium, calcium and other alkali and alkaline earth metals, as well as other elements such as silicon or phosphorus.

The inventors have found that the desired recoveries in step b) can also be obtained by controlling the presence of oxygen and/or oxygen donors in step b) so that it is within suitable limits, if necessary in conjunction with the controlled addition of oxygen scavengers and flux addition.

In one embodiment of the method in accordance with the present invention, the black copper composition used in some of the steps of the method meets at least one of the following conditions, and most preferably all of the following conditions:

- contains at least 51 wt. % copper,

- contains at most 96.9 wt. % copper

- contains at least 0.1 wt. % nickel,

- contains at most 4.0 wt. % nickel,

- contains at least 1.5 wt. % tin,

- contains at most 15 wt. % tin,

- contains at least 1.5 wt. % lead

- contains at most 25 wt. % lead

- contains at most 3.5 wt. % iron, and

- contains at most 8.0 wt. % zinc.

The authors prefer that any black copper that can be used in the process according to the present invention, i.e. also any black copper used in a process step other than step b) meet at least one of the above conditions, and preferably all of these. conditions.

In one embodiment of the method in accordance with the present invention, black copper contains at most 96.9 wt. % or better at most 96.5 wt. % copper, preferably at most 96.0 wt. %, more preferably at most 95.0 wt. %, even more preferably at most 90.0 wt. %, even more preferably at most 85.0 wt. %, even more preferably at most 83.0 wt. %, even more preferably at most 81.0 wt. %, even more preferably at most 80.0 wt. %, even more preferably less than 80.0 wt. % and even more preferably at most 79.0 wt. % copper. This has the additional advantage that the prior process for producing black copper can accept a feed containing many more metals other than copper. It is particularly advantageous in the production of black copper to accept more tin and/or lead, and this higher amount of tin and/or lead can be easily processed into an increased amount of rough solder by-product which has a relatively high economic value.

In one embodiment of the method in accordance with the present invention, black copper contains at least 51 wt. % copper, preferably at least 52 wt. %, more preferably at least 53 wt. %, even more preferably at least 54 wt. %, even more preferably at least 55 wt. %, even more preferably at least 57 wt. %, even more preferably at least 59 wt. %, even more preferably at least 60 wt. %, even more preferably at least 62 wt. %, even more preferably at least 64 wt. %, even more preferably at least 66 wt. %, even more preferably at least 68 wt. %, even more preferably at least 70 wt. %, even more preferably at least 71 wt. %, even more preferably at least 72 wt. %, even more preferably at least 73 wt. %, even more preferably at least 74 wt. %, even more preferably at least 75 wt. %, even more preferably at least 77.5 wt. %, even more preferably at least 80 wt. %, and even more preferably at least 85 wt. % copper.

This has the advantage that a pre-treatment step, such as that proposed in US Pat. % copper, up to about 85 wt. % copper or higher (85.12 wt. % copper in the Example, Table VI) may be omitted.

The inventors have further found that the overall process is more workable and efficient, and generally produces more major products if the copper concentration in ferrous copper remains within a predetermined lower limit. At low concentrations of copper in black copper, other elements make up the remainder. This is quite acceptable and often even desirable if they are valuable metals such as lead, and even more interesting when they also include tin. These metals consume chemicals during any oxidation and/or reduction step, but ultimately most of them end up in the main product stream. If they are metals of lower value or elements that inevitably end up in one of the process waste slags, then the lower concentration of copper is quite disadvantageous because these metals and/or elements consume chemicals in the oxidation stages that are part of the copper refining stages, and/or may consume other chemicals in one of the subsequent recovery steps, such as step c) of the process according to the present invention. In addition, these low value metals or elements take up the volume of the furnace and their presence therefore requires larger furnaces and therefore higher capital costs. Within a given size of equipment available, the presence of these metals or elements increases the restrictions on introducing higher value feedstocks into any of the process steps, such as those containing high concentrations of copper, tin and/or lead. The black copper composition is usually an intermediate product produced by another step in the pyrometallurgical process, i.e. a smelting step. The melting step produces a molten metal product, the so-called "black copper", as well as a liquid slag consisting mainly of metal oxides, usually in the presence of a significant amount of silica. We prefer to obtain a black copper product having at least a predetermined minimum amount of copper in the melting step because the abundant copper acts as an extractant for other valuable metals such as tin and lead. Therefore, maintaining the copper concentration in the black copper composition above this limit results in a higher recovery of these other valuable metals present in the black copper composition, instead of wasting these valuable metals with the smelter slag, in which these metals usually have little or no value, and may even be an extra load.

In one embodiment of the method in accordance with the present invention, black copper contains at least 1.5 wt. % tin, preferably at least 2.0 wt. %, even more preferably at least 2.5 wt. %, even more preferably at least 3.0 wt. %, even more preferably at least 3.5 wt. %, even more preferably at least 3.75 wt. %, even more preferably at least 4.0 wt. %, even more preferably at least 4.5 wt. %, even more preferably at least 5.0 wt. %, even more preferably at least 5.5 wt. %, even more preferably at least 6.0 wt. %, even more preferably at least 6.5 wt. %, even more preferably at least 7.0 wt. %, even more preferably at least 7.5 wt. %, even more preferably at least 8.0 wt. %, even more preferably at least 8.5 wt. %, even more preferably at least 9.0 wt. %, even more preferably at least 9.5 wt. %, even more preferably at least 10.0 wt. %, and even more preferably at least 11.0 wt. % tin. Tin is a very valuable metal, which in its highly pure form is a rather scarce commodity. The authors therefore prefer to produce the maximum amount of tin that their method is capable of processing. In addition, the authors prefer to extract this tin from raw materials with low economic value, in which tin is usually present in low concentrations. Such inexpensive raw materials often contain a large number of elements that are difficult to process in the pyrometallurgical copper refining process, and therefore are usually processed first in the smelting stage. Therefore, the tin contained in such an inexpensive raw material becomes mainly part of the black copper composition. We prefer to process as much tin as possible from such an inexpensive raw material, and therefore prefer to have the black copper composition of the process according to the present invention containing as much tin as possible while respecting the other limitations of the process.

In one embodiment of the method in accordance with the present invention, black copper contains at least 1.5 wt. % lead, preferably at least 2.0 wt. %, even more preferably at least 2.5 wt. %, even more preferably at least 3.0 wt. %, even more preferably at least 3.5 wt. %, even more preferably at least 3.75 wt. %, even more preferably at least 4.0 wt. %, even more preferably at least 4.5 wt. %, even more preferably at least 5.0 wt. %, even more preferably at least 5.5 wt. %, even more preferably at least 6.0 wt. %, even more preferably at least 7.0 wt. %, even more preferably at least 8.0 wt. %, even more preferably at least 9.0 wt. %, even more preferably at least 10.0 wt. %, even more preferably at least 11.0 wt. %, even more preferably at least 12.0 wt. %, even more preferably at least 13.0 wt. %, even more preferably at least 14.0 wt. %, and even more preferably at least 15.0 wt. % lead.

Lead is also a valuable metal. In addition, the presence of lead makes it easier to extract even more valuable metallic tin, because it behaves similarly to tin, it ends up in the same process streams, forming a mixture called "solder", and the resulting solder streams have a higher density and therefore are easier separated from lower density liquid streams such as slag or solid streams such as dross. The authors therefore prefer to have a significant amount of lead in their method. In addition, the authors prefer to extract this lead from raw materials with low economic value, in which lead is usually present in low concentrations. Such inexpensive raw materials often contain a large number of elements that are difficult to process in the pyrometallurgical copper refining process, and therefore are usually processed first in the smelting stage. Therefore, the lead contained in such an inexpensive raw material becomes mainly part of the black copper composition. The authors prefer to obtain the maximum amount of lead from such an inexpensive raw material, and therefore prefer to have a black copper composition of the method in accordance with the present invention containing the maximum amount of lead, subject to other limitations of the method.

The higher presence of tin and/or lead in black copper has the advantage that raw materials containing this tin and/or lead can be processed in a smelting step that is very tolerant of other impurities, much higher than typical steps performed as part of the copper refining process, including any steps associated with the co-production of other non-ferrous metals such as tin and/or lead. These acceptable raw materials are thus usually of much lower quality and therefore also of lower economic value. Most of the tin and/or lead in the black copper of the process according to the present invention ends up in the raw solder by-product, which is a product of relatively high economic value. The economic value enhancement of tin and/or lead in black copper fed to the process according to the present invention is therefore generally much higher than for the same amount introduced as part of a much more concentrated feed, which may be acceptable directly in one of the steps in a copper refining process including auxiliary equipment.

The authors therefore prefer to have a higher amount of tin and/or lead in ferrous copper because this has the advantage that, within the limits of the production of these metals, limited due to equipment limitations, more of these metals are recovered from inexpensive raw materials, and therefore more of these metals can be extracted with a significant increase in their economic value compared to raw materials, obtaining their high economic value in the final product.

In one embodiment of the method in accordance with the present invention, black copper contains at most 15.0 wt. % tin, preferably at most 14.0 wt. %, more preferably at most 13.0 wt. %, even more preferably at most 12.0 wt. %, even more preferably at most 11.0 wt. %, even more preferably at most 10.0 wt. %, even more preferably at most 9.0 wt. %, even more preferably at most 8.0 wt. %, even more preferably at most 7.0 wt. % and even more preferably at most 6.0 wt. % tin. The inventors have found that limiting the concentration of tin in the black copper composition to these upper limits has the advantage that sufficient space is left in the black copper composition for other metals and elements. As discussed above, the presence of copper is very advantageous in the preceding melting step, as is the presence of lead. The authors therefore prefer to keep the concentration of tin within the specified upper limit.

In one embodiment of the method in accordance with the present invention, black copper contains at most 25.0 wt. % lead, preferably at most 24.0 wt. %, more preferably at most 23.0 wt. %, even more preferably at most 22.0 wt. %, yet more preferably at most 21.0 wt. %, even more preferably at most 20.0 wt. %, even more preferably at most 19.0 wt. %, even more preferably at most 18.0 wt. %, even more preferably at most 17.0 wt. %, even more preferably at most 16.0 wt. %, even more preferably at most 15.0 wt. %, even more preferably at most 14.0 wt. %, even more preferably at most 13.0 wt. %, even more preferably at most 12.0 wt. %, even more preferably at most 11.0 wt. %, even more preferably at most 10.0 wt. %, even more preferably at most 9.0 wt. %, even more preferably at most 8.0 wt. %, and even more preferably at most 7.0 wt. % lead. The authors have found that limiting the concentration of lead in the black copper composition to these upper limits has the advantage that sufficient space is left in the black copper composition for other metals and elements. As discussed above, the presence of copper is very advantageous in the preceding melting step, and the presence of a significant amount of tin is also highly desirable. The authors therefore prefer to keep the lead concentration within the specified upper limit.

The authors have found that excessive amounts of tin and/or lead in black copper affect any separation step between copper (and nickel) on the one hand and tin and lead on the other hand. This separation is less clear cut and more tin and/or lead tends to remain with the copper. Even if the copper stream is at least partially recycled, this results in a higher amount of tin and/or lead circulating in the process and an increase in furnace volume. In addition, if the copper stream after such separation, or part thereof, is removed from the process, the higher amount of tin and/or lead in this stream creates an additional burden for its subsequent processing.

In one embodiment of the method in accordance with the present invention, black copper contains at least 0.1 wt. % and at most 4.0 wt. % Nickel (Ni). Preferably, the black copper feed for stage b) contains at least 0.2 wt. % nickel, more preferably at least 0.3 wt. %, even more preferably at least 0.4 wt. %, even more preferably at least 0.5 wt. %, even more preferably at least 0.75 wt. %, and even more preferably at least 1.00 wt. % nickel.

Nickel is a metal that is present in many raw materials containing copper, tin and/or lead, and it is also present in many alloys containing or even based on iron. Nickel, under furnace conditions, exhibits an affinity for oxygen that is lower than that of tin and/or lead and close to and slightly higher than that of copper. Therefore, it is a metal that is difficult to separate from copper using pyrometallurgy. In US 3,682,623, most of the nickel contained in pre-purified black copper (Table VI, 541.8 kg) leaves the process as an impurity in the refined copper product (Table XII, 300 kg) which is cast into anodes (column 19, lines 61 -62). Minor amounts of nickel end up in the lead/tin metal product (Table XV, 110 kg). This process contains a significant recycle stream of black copper, in which the nickel content seems to increase with each cycle (Table XIV, 630 kg compared to Table VI, 500 kg). The authors found that nickel in copper anodes is an element that interferes with the subsequent electrolytic refining step. Under the conditions of the electrolytic purification method, nickel dissolves in the electrolyte, but does not deposit on the cathode. Therefore, it can accumulate in the electrolyte, which can lead to precipitation of nickel salts when their solubility limit is exceeded. But even at lower levels, nickel can lead to passivation of the anodes due to the possible increase in the nickel concentration gradient at the anode surface. The method of US 3,682,623 is thus limited in its ability to process nickel. The melting step in US 3,682,623 can therefore only accept a rather limited amount of feedstock which contains a significant amount of nickel.

The inventors have now found that the process according to the present invention is able to accept much higher amounts of nickel, for example as part of the black copper from the previous melting step. This higher nickel tolerance gives the process of the present invention, as well as any upstream process steps, a wider window of feed acceptance. The process according to the present invention, as well as any of its preceding process steps, can thus accept feedstock that alternative processes known in the art may not accept, or only accept in very limited quantities, and which can thus be more affordable on economically more attractive terms.

Despite the higher nickel tolerance, we have also found that the process according to the present invention can produce an anode copper main product that is richer in copper and contains less nickel compared to the anode copper of US Pat. No. 3,682,623.

In one embodiment of the method in accordance with the present invention, black copper contains at most 3.5 wt. % iron, preferably at most 3.0 wt. %, more preferably at most 2.5 wt. %, even more preferably at most 2.0 wt. %, even more preferably at most 1.80 wt. %, and even more preferably at most 1.60 wt. % iron.

In one embodiment of the method in accordance with the present invention, black copper contains at most 8.0 wt. % zinc, preferably at most 7.5 wt. %, more preferably at most 7.0 wt. %, even more preferably at most 6.5 wt. %, even more preferably at most 6.0 wt. %, even more preferably at most 5.5 wt. %, even more preferably at most 5.0 wt. %, and even more preferably at most 4.7 wt. % zinc.

The authors found that it is desirable to maintain the concentrations of iron and/or zinc within these limits. These metals are usually oxidized in the copper refining stages and require ancillary equipment. Zinc is readily recoverable at any of the recovery steps of this method, and therefore also needs ancillary equipment. In addition to this, these metals take up the volume of the furnace. For these reasons, the Authors wish to limit these metals to the respective concentrations defined above.

In one embodiment of the process according to the invention, the temperature of the slag in step b) and/or step c) is at least 1000°C, preferably at least 1020°C, more preferably at least 1040°C, still more preferably at least 1060°C, even more preferably at least 1080°C, even more preferably at least 1100°C, even more preferably at least 1110°C, even more preferably at least 1120°C, still more preferably at least 1130°C, even more preferably at least 1140°C, and even more preferably at least 1150°C. The inventors have found that the separation between the metal phase and the slag phase is clearer when the temperature of the slag is at a predetermined limit, and preferably above a predetermined limit. Without being bound by any theory The authors believe that a higher temperature gives a better separation, at least because the viscosity of the slag is lower at higher temperatures. The lower viscosity of the slag allows the heavier metal bubbles to coalesce more quickly into larger bubbles and to sink through the slag phase faster until they reach the underlying metal phase and can combine with it. Higher temperatures also benefit from faster reaction kinetics so that the desired equilibrium can be reached more quickly.

The authors, however, also believe that the equilibrium between the metal and the slag phase depends on the temperature. Generally, a higher temperature tends to reduce the difference between different metals in terms of their oxygen affinity under process conditions. The authors therefore prefer to limit the furnace temperature in step b) and/or c) to at most 1300°C, preferably at most 1250°C, and more preferably at most 1200°C. We prefer to apply this limit to most, if not all, steps in the process of the present invention that separate at least two liquid phases, typically a floating slag phase and an underlying metal phase.

In one embodiment of the method according to the present invention, additional raw material is added as fresh feed in step b). The authors prefer to add a raw material containing hard metal, because the melting of this hard metal is able to absorb some of the heat of reaction and helps to keep the temperature of the furnace within the preferred range. The inventors prefer to use for this purpose raw materials which are rich in copper and which may contain at least minor amounts of Sn and/or Pb. The preferred temperature range is limited to a lower limit below which the viscosity of at least one of the liquid phases becomes too high for the furnace to function. The preferred temperature range is limited to an upper limit above which the volatility of valuable metals, in particular tin and/or lead, becomes excessive and recovery of these metals as part of the kiln exit dust becomes prohibitively problematic, complicated and expensive.

At high temperatures, at the stages of melting or cleaning of non-ferrous metal, metals and metal oxides are in a liquid molten state. Metal oxides usually have a lower density than metals and form a separate so-called "slag" phase that floats above the molten metal phase. The metal oxides can thus be separated by gravity as a separate liquid slag phase from the molten metal phase. Silica, usually in the form of conventional sand, may be added as a so-called "flux material", i.e. as a slag thinner and/or to improve the flow of the slag so that it separates more easily from the metal phase and is easier to handle. Silica is also able to bind specific elements and thus also influences the tendency of such elements to become part of the slag phase rather than the metal phase. The inventors have found that the addition of silica is a highly desirable element of the process for many of the steps that are part of the process according to the present invention where the slag phase and the metal phase have to be separated from each other because the silica under many circumstances helps to change the equilibrium between the metal phase and the slag phase in favor of the desired separation into those metals that are desirable in the metal phase and those metals that are preferable to remain in the slag phase. The authors have additionally found that when the slag contains iron and is removed from the furnace and granulated by contacting the hot liquid slag with water, the addition of silica avoids the risk of iron being present in a form that acts as a catalyst to break down water and hence form hydrogen gas, which creates an explosion hazard. The silica also increases the activity of any tin in the slag, causing the SnO ₂ to be reduced to metallic Sn, which goes into the metallic phase. This latter mechanism reduces the amount of Sn that remains in the slag for the same underlying metal composition.

In the operational mode of pyrometallurgy, several chemical reactions take place between different metals and oxides in the furnace. Metals having a higher affinity for oxygen are more easily oxidized and the resulting oxides tend to move into the slag phase, while metals having a lower affinity for oxygen when present as oxides are easily reduced to metals and these metals tend to move into the liquid metal phase. If there is sufficient contact surface and sufficient time, an equilibrium is established between a metal phase in which metals having a lower affinity for oxygen under process conditions are collected, and a slag phase in which metals having a higher affinity for oxygen under process conditions are collected in the form of their oxides.

Metals such as sodium (Na), potassium (K), calcium (Ca) and silicon (Si) have an extremely high affinity for oxygen, and will almost exclusively be recovered with the slag phase. Metals such as silver (Ag), gold (Au) and other precious metals have an extremely low affinity for oxygen, and are almost exclusively recovered with the metal phase. Most other metals typically behave "in-between" these two extremes, and their behavior can be further influenced by the presence of other elements or substances, or perhaps their relative absence.

The metals of interest for the present invention, under typical conditions in a non-ferrous metal refining furnace, have an affinity for oxygen, and will tend to partition between the metal and slag phases. From lower to higher affinity for oxygen, and hence from relatively high to lower affinity for the metal phase, these metals can be ranked roughly as follows: Au > Ag >> Bi/Cu > Ni > As > Sb > Pb > Sn > > Fe > Zn > Si > Al > Mg > Ca. For convenience, this can be called a ranking of metals from more inert to less inert, but this qualification must be related to the specific conditions and circumstances of the pyrometallurgical methods for obtaining non-ferrous metals, and may not be correct when trying to transfer to other areas. The relative position of individual metals in this list may depend on the presence or absence of other elements in the furnace, such as, for example, silicon.

The equilibrium distribution of the metal between the metal phase and the slag phase may also depend on the addition of oxygen and/or oxygen scavenging materials (or reducing agents) to the liquid bath in the furnace.

The addition of oxygen converts some of the metals in the metal phase to their oxidized form and these oxides then move into the slag phase. Metals in the metal phase that have a high affinity for oxygen will be more prone to such transformation and movement. Their equilibrium distribution between the metal phase and the slag phase can thus be more subject to change.

The opposite result can be obtained by adding oxygen scavenging materials. Suitable oxygen consumers may be, for example, carbon and/or hydrogen in any form, such as in organic materials such as wood, or other fuels such as natural gas. Carbon and hydrogen will readily oxidize ("burn") and convert to H ₂ O and/or CO/CO ₂ , components that readily leave the liquid bath and carry away the oxygen contained therein. Metals such as Si, Fe, Al, Zn and/or Ca are also suitable reducing agents. Particularly interesting in this regard are iron (Fe) and/or aluminum (Al) because of their easy availability. When oxidized, these components will reduce some of the metals contained in the slag phase from their oxidized state to their metallic state, and these metals will then move into the metallic phase. There are metals present in the slag phase that have a lower affinity for oxygen, which will be more likely to undergo this reduction reaction and move in the opposite direction.

In the melting step, one of the goals is to reduce oxides of valuable nonferrous metals that come with power to their respective reduced metals. The direction and rate of the reactions occurring in the melting step can be further controlled by controlling the nature of the atmosphere in the furnace. Alternatively, or additionally, an oxygen-donating material or an oxygen-scavenging material may be added to the furnace.

A very suitable oxygen scavenging material for such operations is metallic iron, and preferably scrap iron. Under typical operating conditions, iron will react with hot oxides, silicates, and other metal compounds having a lower affinity for oxygen than iron, producing a melt containing these metals in elemental form. Typical reactions include:

MeO+Fe → FeO+Me+heat

(MeO) _x SiO ₂ +x Fe → (FeO) _x SiO ₂ +x Me + heat

The temperature of the bath is kept high by the heat of the exothermic reaction and the heat of combustion. The temperature can be easily maintained within a range where the slag remains liquid and the evaporation of lead and/or tin remains limited.

Each of the reduction reactions taking place in the melting furnace forms an equilibrium. Thus, the transformation realized through each reaction is limited by an equilibrium defined by relationships such as the following:

The parameters in these formulas represent the activity of said chemical components under operating conditions, which is often the product of the concentration of the component and the activity coefficient of the component under operating conditions, due to which the latter is not always equal to 1.0, and the same is true for other components. The inventors have found that these activity coefficients may depend on the presence of other chemical compounds, such as so-called flux compounds, sometimes also referred to as slag formers, in particular the addition of silica.

When Me is copper, K1 and K2 are high at normal reaction temperatures, and the reduction of copper compounds thus proceeds substantially to completion. In the case of lead and tin, K1 and K2 are both relatively low, but the copper in the metal phase extracts the metallic lead and tin from the slag reaction zone, thereby lowering the activities of these metals in the slag and bringing the reduction of the combined lead and tin to completion.

The vapor pressure of zinc is relatively high at a typical reaction temperature, and a large proportion of zinc, unlike lead and tin, can easily volatilize from the furnace. The zinc vapor leaving the furnace is oxidized by air, which can penetrate, for example, between the furnace neck and the hood and/or exhaust pipe. The resulting zinc oxide dust is condensed and collected by conventional dust collection systems.

Preferably, the content of each of copper, tin and lead in the slag in the melting furnace is reduced to 0.5 wt. % or less. To do this, the metal phase must contain enough copper to extract lead and tin from the slag. Also for this reason, the Authors prefer that the concentration of copper in black copper fed to the process in accordance with the present invention be above the lower limit defined herein.

In one embodiment of the process according to the present invention, step c) comprises adding a first reducing agent, preferably by adding it to the first copper refining slag prior to reducing the first copper refining slag. The authors found that the addition of a reducing agent helps in achieving the desired chemical recovery. The inventors have found that the first reducing agent may be a gas such as methane or natural gas, but may also be a solid or liquid such as carbon, hydrocarbon, and even aluminum or iron.

In one embodiment of the process according to the present invention, the first reducing agent comprises, and preferably is, a metal having, under process conditions, a higher affinity for oxygen than tin, lead, copper and nickel, preferably metallic iron, and more preferably scrap iron. The authors prefer to use iron, preferably scrap iron, as the reducing agent due to its high availability under economically very attractive conditions. The inventors have found that the addition of a solid reducing agent may have the additional benefit that the furnace requires less additional heating to maintain or reach the desired temperature. The authors have found that this benefit can be quite large because additional heating by combustion of the fuel using air and/or oxygen may not be required at all to achieve the desired temperature. The authors have additionally found that step c) can further benefit from the addition of silica, as explained above.

In one embodiment, the method in accordance with the present invention further comprises the following step:

d) partially oxidizing the first liquid bath, thereby forming a first diluted copper metal composition and a first solder refining slag, followed by separating the first solder refining slag from the first diluted copper metal composition.

The inventors have found that step d) is very suitable for concentrating the major amount of solder metals, i.e. tin and/or lead present in the first liquid bath, into the first solder refining slag without having to carry away a significant portion of the copper, and possibly also the nickel, present in the first liquid bath, and at the same time recovering a metal stream that contains most of the copper and nickel present in the first liquid bath, without the need to carry away a significant amount of metals that have a higher affinity for oxygen than tin and/ or lead, under the conditions of step d). In particular, step d) removes most of the copper and nickel, if present, as part of the first dilute copper metal composition, and thereby produces a slag phase that contains only small amounts of copper and/or nickel, but relatively large amounts of tin and/ or lead, together with most metals having, under process conditions, an even higher affinity for oxygen than lead and/or tin. On the other hand, step d) produces a metal stream which is very suitable for recovering its metal content because it is rich in valuable metals with very little metal content of little or no value.

The inventors have found that the formation of a diluted copper metal composition in step d) has the main advantage of obtaining a relatively clear separation into copper in a high purity copper stream, potentially up to anode quality, and into a rough solder stream such as the first rough solder metal composition. obtained in step e), which is further described below in this document. Any elemental copper acts in step d) as an extractant for tin and/or lead, as well as before this step. Therefore, copper acts as a carrier for tin and/or lead. Carrying out a portion of the copper in steps b) and/or h), which is further described herein below, with appropriate slag phases, removes more tin and/or lead from the main copper stream of the process, which passes as a metal stream through the stages of the copper refining process. b) and/or h) to become a main copper product stream rich enough in copper for further processing into a high purity copper product. Copper is also useful as a solvent for tin and/or lead in step c) of the process. The copper present in step c) thus helps to retain the tin and/or lead in the metal phase of step c), i.e. in the first lead-tin metal composition, and reduces the amount of tin and/or lead that may enter the first spent slag from step c).

The inventors have further found that the oxidation step d), by producing a first diluted copper metal composition as the metal phase, can produce a first solder refining slag richer in tin and/or lead, in particular both tin and lead, relative to the amount of copper that is carried away with this first solder refining slag. Since the first solder refining slag is enriched in tin and/or lead, this facilitates the subsequent recovery of solder metals (ie, tin and/or lead) from this first solder refining slag.

The authors also found that the formation of the first dilute copper metal composition in step d) has the added benefit that more tin and/or lead can be introduced with the feed. This greatly expands the acceptance criteria for any raw material that may be additionally fed into stage b), i.e. beyond black copper, as well as downstream stages such as stages h), c) and d), and stage j) , which is further described later in this document. In addition, it also significantly weakens the acceptance criteria for black copper itself. This feature thus greatly expands the acceptance criteria for the raw materials used in the production of ferrous copper, usually obtained as the main product in the smelting stage. The smelting stage can therefore accept much lower quality raw materials that are much more readily available at economically more attractive terms.

The inventors have additionally found that the formation of the first dilute copper metal composition has the additional advantage that in step d) a better separation can be obtained into copper and nickel to be included in the first dilute copper metal composition, and tin and lead to be included. into the first solder refining slag.

The inventors have found that performing step c) upstream or prior to step d) makes it possible to achieve in step d) a favorably high recovery of copper and/or nickel in the metal product, as well as a relatively low amount of copper and/or nickel, if any, in the first solder refining slag.

Copper and/or nickel found as contaminants in the green solder, together with the iron present, are a burden to the rough solder refining process, particularly when done using silicon metal, and are thus undesirable. The authors found that below stage d) raw solder metal can be produced downstream, which contains significantly less than 18.11 wt. % copper, nickel and iron together, as listed in US 3,682,623.

The inventors have additionally found that the first dilute copper metal phase that is recovered from the slag reworking furnace can contain much less base metals. In patent document US 3682623, black copper for recycling (Table XIV) contains only 97.52 wt. % in the amount of Cu, Sn, Pb and Ni, leaving a balance of 2.48 wt. %. This difference has the advantage that the first diluted copper metal phase becomes much easier for further processing, especially for recovering the valuable metals that the stream contains.

We have additionally found that the first dilute copper metal phase that is recovered in step d) may contain relatively important amounts of tin and/or lead. This has the advantage that the corresponding slag phase obtained in step d), i.e. the first solder refining slag, which with sufficient time and mixing should be in equilibrium with the first dilute copper metal phase, is also richer in tin and/or lead. As a result, more tin and/or lead is made available for recovery downstream by additional processing of the first solder refining slag to recover solder metals, ie tin and/or lead. The overall result is that more rough solder can be produced relative to the amount of copper that is produced in the process according to the present invention. This benefit brings the associated additional benefit that a significantly higher amount of high purity tin product can be produced relative to the copper production rate of the process according to the present invention. Since co-production of tin generates additional income on top of the income from copper production, this advantage can be a significant economic benefit for the process operator.

We have additionally found that the greater presence of tin and/or lead in the first dilute copper metal phase that is recovered in step d) makes it technically more feasible and economically more interesting to recover the tin and/or lead from this stream by treating it separately instead of to simply recycle this stream to the first stage b) of copper refining, as is done in US Pat. No. 3,682,623. separating into a stream with a higher concentration of tin and/or lead and a stream with a higher concentration of copper and/or Nickel. The formation of another stream with a higher concentration of tin and/or lead makes it possible to obtain a tin by-product of even higher purity compared to the production of copper, which is an additional advantage. Even if, after this additional separation, at least a portion of the stream with a higher concentration of copper and/or nickel is returned to the first stage b) of copper refining, similar to US 3682623, then there will be less tin and/or lead in this recycle relative to the copper content , and therefore more oven volume becomes available to handle additional fresh feed at the stages that this recycle will go through.

The inventors have also found that the method including step d) is very effective for producing the slag phase, i.e. the first solder refining slag, which is particularly suitable for producing a rough solder stream that can serve as an intermediate for the recovery of tin products and/ or high purity lead. The authors found that this efficiency is obtained in particular due to the production in step d) of the first dilute copper metal composition, and also due to the sequence of oxidation and reduction steps defined in the method in accordance with the present invention.

In one embodiment, the method in accordance with the present invention further comprises the following step:

e) partially reducing the first solder refining slag, thereby forming a first rough solder metal composition and a second solder refining slag, followed by separating the second solder refining slag from the first rough solder metal composition.

This step e) produces a rough solder stream rich in tin and/or lead, as well as containing most of the relatively small amounts of copper and/or nickel that were captured by the first solder refining slag. The first rough solder stream is suitable for further processing to further enrich in tin and/or lead, for example by processing with silicon metal, as described in DE 102012005401 A1. Alternatively or additionally, this rough solder stream, optionally after an enrichment step to increase the tin and/or lead content, can be further adjusted as described in WO 2018/060202 A1 and the like, and then subjected to distillation and tin recovery and /or lead as high purity metal products as described in the same document.

The inventors have found that the reduction in step e) can be at least partially carried out by adding a suitable metal stream (second reducing agent), i.e. by adding a metal composition which contains metals having, under process conditions, a higher oxygen affinity than tin. and/or lead such as zinc, silicon, magnesium, iron, calcium or aluminium. This metal stream preferably also contains tin and/or lead, and optionally may also contain some antimony and/or arsenic. These additional antimony, tin and/or lead easily become part of the first rough solder metal composition from step e) and can be easily recovered downstream as part of the refined metal main product. The metal addition stream preferably contains only minor amounts of nickel and/or copper, i.e. metals that are also likely to become part of the first rough solder metal composition in step e), but which can create additional process workload and additional operating costs, such as an additional consumption of silicon when a silicon treatment step is provided downstream in refining the first rough solder metal composition. Also, iron is preferably only present in a limited amount because not all of the added iron may enter the slag phase, but instead will leave step e) with the first braze metal composition and increase the load on the downstream process.

We have found that in step e) recovery of solder metals into the first rough solder metal composition can be favorably high and any carryover of tin and/or lead, and copper and/or nickel, with the second solder refining slag can be kept favorably low.

In one embodiment, the method in accordance with the present invention further comprises the following step:

f) partial reduction of the second solder refining slag, thereby forming a second lead-tin metal composition and a second waste slag, followed by separating the second waste slag from the second lead-tin metal composition.

The inventors have found that it is advantageous to provide for an additional reduction step f) after step e) of rough solder production, in particular a recovery step of the second solder refining slag that was obtained in step e). The inventors have found that more valuable metals can be recovered from this second solder refining slag using step f), making the remaining slag even more suitable for use in a valuable end application, and/or to dispose of this slag as waste. We have additionally found that the additional reduction step f) is also capable of reducing leachable metals in the slag, such as lead, to sufficiently low levels such that the slag after step f) can be further used as a valuable material, or safely disposed of, all with a very limited number of additional processing steps, and possibly no additional processing steps at all, to reduce the concentration of sensitive metals such as lead and/or zinc.

In one embodiment, the method according to the present invention comprises adding the first copper-containing fresh feed in step f), preferably prior to the recovery of the second solder refining slag.

The authors have found that the addition of copper in step f) of the reduction provides a significant benefit because copper can act as an excellent extractant for any other valuable metals that remain in the second solder refining slag after step e), and that this beneficial extraction can be performed without losing significant amounts of copper in the second waste slag that is produced in step f).

The authors have additionally found that the copper-containing fresh feed that can be added in step f) may contain significant amounts of other valuable metals, in particular zinc, nickel, tin and/or lead. The inventors have found that if sufficient copper is provided, that the losses, especially of tin and/or lead, with the second waste slag can be kept very low and therefore do not compromise the possible further use or direction of this second waste slag and do not create an economically significant loss of precious metals.

The authors have found that a wide range of materials are suitable as copper-containing fresh feed for step f). The inventors, however, prefer that the copper-containing fresh feed for step f) contain only a limited amount, and preferably no combustible substances at all, i.e. substances that are easily oxidized under process conditions, for example organic materials such as plastics and/or hydrocarbons, residues fuel or oil, etc., so that the temperature in step f) remains easily controlled.

In one embodiment of the process according to the present invention, the first copper-containing fresh feed contains ferrous copper and/or spent or discarded copper anode material.

The inventors have found that in step f) a significant amount of black copper similar in composition to the black copper provided in step a) can be added in step f) to extract more valuable metals from the second solder refining slag from step e) without excessive losses of especially valuable metals with the second spent slag from stage f). The inventors have found that the amounts of such black copper from the previous smelting step that can be fed to step f) are very significant, and may even be on the order of the amount of black copper that is provided in step a) as feed to step b). The inventors have found that the inclusion of step f) in the process according to the present invention significantly increases the ability to process smelting ferrous copper, and therefore to process higher quantities of low quality raw materials, resulting in low cost valuable metals and therefore high economic potential. The inventors have found that this way of performing step f) has the additional advantage that a significant portion of the black copper from the preceding smelting step can be processed without all the black copper that would have to pass through at least the first step b) of the copper refining sequence. Any metals in the black copper feed stream for step f) which, under process conditions, have a higher oxygen affinity than copper, are likely already removed before the copper from this fresh black copper feed for step f) can enter step b ) and go through the copper refining process sequence of steps b), h) and j).

The inventors have also found that step f) is also very suitable for introducing spent and/or discarded copper anode material. The production of high quality copper usually contains an electrolysis step in which copper is dissolved from the anode into an electrolyte and deposited on the cathode. The anode is usually not consumed completely and is removed as spent copper anode material from the plating bath before the last copper has been dissolved in it. The inventors have found that step f) is very suitable for the introduction of such spent copper anode material. Copper anodes for this copper electrolysis step are usually cast by pouring a suitable amount of anode grade molten copper into a mold and solidifying the copper as it cools. For copper electrolysis to function well, anodes must meet fairly stringent requirements in terms of size and shape. Non-compliant anodes are preferably not used and are discarded copper anode material. The inventors have found that step f) is also very suitable for the introduction of such discarded copper anode material.

The authors prefer to introduce spent and/or rejected copper anode material in solid form with little or no heating. This has the advantage that the melting of this material consumes at least part of the heat of the reactions occurring in step f).

In one embodiment of the process according to the present invention, step f) comprises adding a third reducing agent in step f), that is, a step for reducing the second solder refining slag.

The inventors have found that the third reducing agent improves the result of the reduction step f) towards the desired separation of valuable metals into the second lead-tin metal composition and retention of discarded metals in the second spent slag. The inventors have found that the third reducing agent may be a gas such as methane or natural gas, but may also be a solid or liquid such as carbon, hydrocarbon, and even aluminum or iron.

In one embodiment of the process according to the present invention, the third reducing agent comprises, and preferably is, a metal having, under process conditions, a higher oxygen affinity than tin, lead, copper and nickel, preferably metallic iron, and more preferably scrap iron. The authors prefer to use iron, preferably scrap iron, as the reducing agent because of its high availability under economically very attractive conditions. The inventors have found that the addition of a solid reducing agent may have the additional benefit that the furnace requires less additional heating to maintain or reach the desired temperature. The authors have found that this benefit can be quite large because additional heating by combustion of the fuel using air and/or oxygen may not be required at all to achieve the desired temperature. The authors have additionally found that step f) can further benefit from the addition of silica, as explained above.

We prefer to add in step f) some iron-rich third reducing agent, preferably in the form of a multi-metal material, because this multi-metal material is more readily available at better terms than higher purity tin, higher purity copper, or higher purity iron. . Another suitable material would be electric motors, preferably used electric motors due to their high iron content in the cores and copper windings. The authors found that copper and/or tin can be easily retained in the metal phase and kept from moving to the slag phase, while any iron in this copper-containing fresh feed is easily moved to the slag phase as iron oxide, which aids chemical reduction. other metals which, under process conditions, have a lower affinity for oxygen than iron.

In one embodiment of the method according to the present invention, the method further comprises the step of:

g) recycling at least a portion of the second lead-tin metal composition to step c), preferably adding most, if not all, of the second lead-tin metal composition to step c), preferably before recovering the first copper refining slag.

The inventors have found that the valuable metals in the second lead-tin metal composition from step f) can be easily recovered by adding this composition in step c). The metals in the second lead-tin metal composition having a higher oxygen affinity under the process conditions readily oxidize and result in the reduction of those metals fed to step c) that have a lower oxygen affinity under the same conditions. The presence in step c) of additional metals from step f) results in incomplete reduction of the metals present as oxides in the first copper refining slag. As a result, more valuable metals such as Cu, Ni, Sn, Pb, Sb, As are transferred to the metal phase in step c), while less valuable metals such as Fe, Si and Al are transferred to the first waste slag produced at step c). Therefore, the addition of this second lead-tin metal composition in step c) improves the desired separation of the other feedstock for step c) in combination with obtaining the desired separation of the metals that were recovered in step f).

In one embodiment of the method according to the present invention, step e) comprises adding a second reducing agent, preferably to the first solder refining slag, prior to its reduction. The inventors have additionally found that in order to carry out the reduction in step e), in addition to the metal stream that may be added to step e), or alternatively, a reducing agent may be added in step e). The authors found that the addition of a reducing agent helps in achieving the desired chemical recovery. The inventors have found that the second reducing agent may be a gas such as methane or natural gas, but may also be a solid or liquid such as carbon, hydrocarbon, and even aluminum or iron.

In one embodiment of the process according to the present invention, the second reducing agent comprises, and preferably is, a metal having, under process conditions, a higher affinity for oxygen than tin, lead, copper and nickel, preferably metallic iron, and more preferably scrap iron. The authors prefer to use iron, preferably scrap iron, as the reducing agent due to its high availability under economically very attractive conditions. The inventors have found that the addition of a solid reducing agent may have the additional benefit that the furnace requires less additional heating to maintain or reach the desired temperature. The authors have found that this benefit can be quite large because additional heating by combustion of the fuel using air and/or oxygen may not be required at all to achieve the desired temperature. The authors have additionally found that step e) can further benefit from the addition of silica, as explained above.

In one embodiment of the process according to the present invention, a first fresh feed containing Pb and/or Sn is added in step e), preferably to the first solder refining slag before it is reduced, preferably a first fresh feed containing Pb and/or Sn, containing and preferably representing the dross obtained from the subsequent processing of concentrated streams of Pb and/or Sn.

The inventors have found that step e) is also a very suitable position in the process for introducing materials which are rich in tin and/or lead and low in copper and nickel, but which may contain metals which, under process conditions, have a higher affinity for oxygen than tin and lead. Their addition in step e) has the advantage that the tin and/or lead can be easily recovered as part of the first rough solder metal composition and removed from the process, while the so-called "less noble" metals follow the short and direct process path into the second spent solder. slag produced in subsequent step f).

The inventors have found that step e) is very suitable for recovering tin and/or lead, and optionally antimony and/or arsenic, contained in raw materials or process by-products that are rich in such metals but have a relatively low content of copper and/or nickel. The inventors have found that the first Pb and/or Sn containing fresh feed may additionally contain metals which, under process conditions, have a higher oxygen affinity than tin and/or lead, such as sodium, potassium, calcium. Such metals may be included, for example, as part of the chemicals used in subsequent steps to clean up a tin and/or lead rich stream, such as the first rough solder metal composition or subsequent derivatives thereof. The inventors have found that step e) is very suitable for recovering valuable metals from the dross by-product formed in one of the purification steps performed as part of the methods disclosed in patent document WO 2018/060202 A1 and the like. Such dross by-product streams typically carry economically significant amounts of tin and/or lead, and also contain other metals that may have been introduced as part of the process chemicals.

In one embodiment, the method according to the present invention comprises adding fresh feed to the furnace charge in step d). The authors have found that step d) is very suitable for the recovery of valuable metals from their oxides. Copper, tin and/or lead added as part of the fresh feed in step d) in oxide form can easily be recovered as elemental metal in the metal phases formed in step d), e) or f) under process conditions. The inventors have found that step d) is therefore suitable for recycling, for example, volumes of final slag containing specific metals above desired levels and therefore economically or environmentally less suitable for disposal, or volumes of slag layers that collect in a crust that can build up on the inside of containers used to transport molten slags from one stage of the process to the next. The authors have found that the addition of such materials as fresh feed in step d) provides improved recovery of valuable metals from them.

In one embodiment of the present invention, the method further comprises the following step:

h) partially oxidizing the first copper-rich metal phase, thereby forming a second copper-rich metal phase and a second copper refining slag, followed by separating the second copper refining slag from the second copper-rich metal phase.

The inventors have found that the first copper-rich metal phase formed in step b) can be further enriched in copper by subjecting this stream to a subsequent oxidation step. The subsequent oxidation step results in the formation of a second copper refining slag, which may contain an economically significant amount of valuable metals other than copper, but which also contains an economically significant amount of copper.

In one embodiment of the method in accordance with the present invention, including stage h), at least 37.0 wt. % of the total amount of tin and lead that is processed in process steps b) and/or h) is recovered with the first copper refining slag and the second copper refining slag.

In one embodiment of the method in accordance with the present invention, including stage h), at least 37.5 wt. % and preferably at least 38 wt. % of the total amount of tin and lead that is processed in process steps b) and/or h) is recovered in the first copper refining slag and the second copper refining slag together, preferably at least 40 wt. %, more preferably at least 45 wt. %, even more preferably at least 50 wt. %, even more preferably at least 60 wt. %, even more preferably at least 70 wt. %, even more preferably at least 80 wt. %, even more preferably at least 85 wt. %, even more preferably at least 90 wt. %, even more preferably at least 92 wt. %, even more preferably at least 94 wt. %, and even more preferably at least 95 wt. %. The inventors have found that a high recovery of tin and/or lead in the upper slags of the copper refining sequence is advantageous for obtaining a better separation between copper on the one hand and solder metals, tin and/or lead on the other hand.

In one embodiment of the method in accordance with the present invention, at least 8.5 wt. % of the total amount of tin and lead, which is processed at the stage of the method b), is recovered in the first copper refining slag, preferably at least 10 wt. %, more preferably at least 15 wt. %, even more preferably at least 20 wt. %, even more preferably at least 30 wt. %, even more preferably at least 40 wt. %, even more preferably at least 45 wt. %, even more preferably at least 50 wt. %, even more preferably at least 55 wt. %, even more preferably at least 60 wt. %, even more preferably at least 64 wt. %, and even more preferably at least 68 wt. %. The authors found that the earlier in the sequence of steps b) and h) of copper refining most of the tin and/or lead is oxidized and moved into the copper refining slag phase, the clearer the overall separation between copper on one side and solder metals on the other side can be made. .

In one embodiment of the method in accordance with the present invention, including stage h), at least 41.0 wt. % of the total amount of tin that is processed in process steps b) and/or h) is recovered in the first copper refining slag and the second copper refining slag together, preferably at least 45 wt. %, more preferably at least 50 wt. %, even more preferably at least 55 wt. %, even more preferably at least 60 wt. %, even more preferably at least 65 wt. %, even more preferably at least 70 wt. %, even more preferably at least 75 wt. %, even more preferably at least 80 wt. %, even more preferably at least 85 wt. %, even more preferably at least 90 wt. %, and even more preferably at least 92 wt. %.

In one embodiment of the method in accordance with the present invention, including stage h), at least 34.5 wt. % of the total amount of lead that is processed in process steps b) and/or h) is recovered in the first copper refining slag and the second copper refining slag together, preferably at least 35 wt. %, more preferably at least 40 wt. %, even more preferably at least 45 wt. %, even more preferably at least 50 wt. %, even more preferably at least 55 wt. %, even more preferably at least 60 wt. %, even more preferably at least 65 wt. %, even more preferably at least 70 wt. %, even more preferably at least 75 wt. %, even more preferably at least 80 wt. %, even more preferably at least 85 wt. %, even more preferably at least 90 wt. %, and even more preferably at least 91 wt. %.

In one embodiment of the method in accordance with the present invention, the method further comprises the following step:

i) adding at least a portion of the second copper refinery slag to the first liquid bath and/or adding at least a portion of the second copper refinery slag in step d).

The inventors have found that the composition of the second copper refining slag is very suitable for addition to the first liquid bath. The authors therefore prefer to add all of the second copper refining slag to the first liquid bath. This stream is suitable first because the second copper refining slag is already relatively rich in the valuable metals of interest tin and lead, and also includes a significant amount of copper, which can act downstream as an extractant for non-copper metals such as like tin and lead. Secondly, this second copper refining slag contains only small amounts of metals having, under process conditions, a higher affinity for oxygen than tin and/or lead, more specifically metals that are less desirable in the final refined metal products of copper, tin and/or lead, and which must be removed from the process as part of the spent slag. Since the second copper refining slag contains relatively few of these metals, the addition of this slag to the first liquid bath does not take up a large waste volume of the furnace in any of the subsequent steps in the process sequence d), e) and f), i.e. in the preferred process path for such " less noble" metals for their entry into the waste slag, in this case the second waste slag.

The inventors have found that the method according to the present invention, comprising steps b), h), c), i) and d), is very effective for producing the slag phase, i.e. the first solder refining slag, which is particularly suitable for producing a flow solder, i.e. the first rough solder metal composition that can serve as an intermediate for the recovery of high purity tin and/or lead products. The authors found that this efficiency is obtained in particular due to the production in step d) of the first dilute copper metal composition, as well as due to the sequence of oxidation and reduction steps, as previously determined.

The authors have additionally found that the method according to the present invention is also very energy efficient. In step i) the second copper refining slag that was added to the first liquid bath and/or in step d) acts as an oxidizing agent for the impurities in the first liquid bath. The copper oxides in the second copper refining slag are readily reduced to elemental copper in this bath, thereby releasing oxygen to convert those metals which, under process conditions, have a higher oxygen affinity than copper, from their elemental metallic form to oxides. Therefore, the elemental copper formed in step d) moves into the metal phase and leaves step d) with the first diluted copper metal composition. The metals converted to their oxides in step d) will move into the slag phase and be recovered in the first solder refining slag. The inventors have found that in step d) a significant amount of Sn and/or Pb can be transferred from the metal phase that is introduced into the furnace to the first solder refining slag that is present at the end of step d). The authors have also found that these chemical transformations in step d) of copper oxides to elemental copper and of tin, lead or other metals to their oxides can be achieved with relatively little additional energy input, external oxidizing agents and/or reducing agents, and therefore with a relatively limited consumption of energy or chemicals.

In one embodiment of the method in accordance with the present invention, the method further comprises the following steps:

j) partially oxidizing the second copper-rich metal phase, thereby forming a third copper-rich metal phase and a third copper refining slag, followed by separating the third copper refining slag from the third copper-rich metal phase,

k) adding at least a portion of a third copper refining slag to the first diluted copper metal composition, thereby forming a second liquid bath, and/or adding at least a portion of a third copper refining slag in step l);

l) partially oxidizing the second liquid bath, thereby forming a first high copper metal composition and a third solder refining slag, followed by separating the third solder refining slag from the first high copper metal composition.

The inventors have found that the second copper-rich metal phase formed in step h) can be further enriched in copper by subjecting this stream to a subsequent oxidation step j). The subsequent oxidation step results in the formation of a third copper refining slag which may still contain an economically significant amount of valuable metals other than copper, but which also contains an economically significant amount of copper. The advantage is that these valuable non-copper metals become recoverable from the third copper refining slag in a much simpler manner compared to the non-copper metals remaining in the third copper-rich metal phase if this stream were subjected to a copper electrowinning step to recover high purity copper, in which non-copper metals tend to create unnecessary problems for the process. Some non-copper metals remain during electrolytic cleaning in the so-called anode sludge, and some other non-copper metals dissolve in the electrolyte.

The authors additionally found that three successive oxidation steps as part of the sequence b), h) and j) can produce from the starting raw material black copper, which may not have very much copper, but may be rich in tin and/or lead, a third rich in copper a metal phase having a concentration of copper that is highly suitable for further electrolytic refining and hence can be called "anode grade". The authors found that the specified sequence of stages of oxidation in the state of black copper containing no more than 75 wt. % copper to produce a third copper-rich metal phase that contains as much as 99.0 wt. % copper. The inventors have additionally found that, together with the treatment of black copper fed to stage b), additional copper-containing feedstock can be processed using the indicated sequence of oxidation stages.

The inventors have found that the composition of the third copper refining slag is very suitable for addition to the second liquid bath. The authors therefore prefer to add all of the third copper refining slag to the second liquid bath.

This stream is firstly suitable because the third copper refining slag still contains an economically significant amount of the valuable metals of interest tin and/or lead, and is also relatively rich in copper, which can be used as a useful extractant for non-copper metals such as tin and/or lead.

Secondly, the third copper refining slag contains a very small amount of metals having, under process conditions, a higher affinity for oxygen than tin and/or lead, more specifically metals that are less desirable in final refined copper, tin and/or lead metal products. , and which are preferably removed from the process according to the present invention as part of the spent slag. Since the third copper refining slag contains very little of these metals, the addition of this slag to the second liquid bath does not take up a large waste volume of the furnace in any of the subsequent steps in the process including step l), as well as in any of the subsequent steps in the process path by which such "less noble" metals must follow before they end up in the waste slag.

The inventors have additionally found that any further recovery of valuable metals from a second liquid bath such as in step l) can be highly energy efficient due to the addition of at least a portion of the third copper refining slag in step k). In step k), the third copper refining slag, which is added to the second liquid bath prior to further metal recovery steps, acts as an oxidizing agent for impurities in the second liquid bath. The copper oxides in the third copper refining slag are readily reduced to elemental copper in step l), thereby releasing oxygen to convert those metals which, under process conditions, have a higher oxygen affinity than copper, from their elemental metallic form to oxides. Consequently, the elemental copper formed during the processing of the second liquid bath in step l) moves into the metal phase, which in step l) is the first metal composition with a high copper content. The metals converted to their oxides in step l) move into the slag phase, i.e. third solder refining slag. The inventors have found that in step l) a significant amount of Sn and/or Pb can be transferred from the metal phase being fed into the slag phase. The authors have also found that these chemical transformations in step l) of copper oxides to elemental copper and of tin, lead and/or other metals to their oxides can be achieved with a relatively limited amount of additional energy input, external oxidizing agents and/or reducing agents, and therefore with relatively limited consumption of energy or chemicals.

The inventors have found that in step l) most of the copper and nickel present in the first dilute copper metal composition as well as in the third copper refining slag can be recovered with the high copper content first metal composition, along with a portion of the bismuth and antimony which may be present, while most of the tin and/or lead contained in these streams may be recovered with the third solder refining slag. The authors found that the third solder refining slag can become advantageously rich in tin and/or lead, as well as relatively poor in copper, so that this slag can be relatively easily processed further to recover most of the solder metals it contains into a stream that resembles that of rough solder. and is suitable for processing as a rough solder flow.

In one embodiment of the process according to the present invention comprising steps b), h), c), d), j) and l), the first high copper metal composition is at least partially returned to a suitable upstream location in way. Preferably this location is step b), but a portion of the recycled stream may be recycled to step h) and/or step j) and/or step c) and/or step d).

The inventors have found that, on the one hand, step l) is also very suitable for providing a way to remove at least a portion of the nickel from the complete casting process, because any nickel introduced at any previous point in the process is very likely to become part of the first metal composition. with a high copper content. On the other hand, the Authors have found that if no nickel or only a small amount of nickel is added to the full process feed, then the first high copper metal composition has a composition comparable to the black copper feed provided in step a), and therefore, this stream of the first metal composition with a high content of copper can be easily returned to stage b), or alternatively and/or in addition, partially to any of the subsequent stages h) and j) of copper oxidation to recover the copper contained therein as part a third copper-rich metallic phase. The process described in US Pat. No. 3,682,623 includes such recycling of the copper-rich stream to a first black copper oxidation stage. However, any recycling of the first high copper metal composition to step b) or one of the subsequent steps h) or j) is advantageous over the prior art due to earlier removal of impurities to one of the spent slags, such as the first spent the slag produced in step c) and/or the second waste slag produced in step f).

The inventors have found that if nickel is present in the process feed stream, then partial recycling of the first copper-rich metal composition to an upstream location in the process, such as step b), h) or j), has the advantage that the nickel is concentrated to high level in the first high copper metal composition compared to a process without such partial recycling. This concentration effect has the advantage that recovering a particular amount of nickel from a process, for example to keep nickel levels in particular process steps below particular levels, requires a lower amount of copper to be recovered along with that amount of nickel. This has the advantage that nickel removal from the process becomes more efficient, further processing of the recovered copper/nickel mixture can be done more efficiently and with smaller equipment, and can also be done more cost-effectively, i.e. with less energy and/or chemicals. .

The inventors have found that the first high copper metal composition that is recovered from the process can be further processed to recover its copper and nickel content by means that are known in the art, or preferably by means described in the concurrently filed patent application EP-A-18172598.7, filed May 16, 2018 titled "Improvement in electrolytic copper refining".

In one embodiment of the method according to the present invention, comprising step l), at the end of step l), the first high copper metal composition is only partially removed from the furnace, and part of this metal composition remains in the furnace along with the third solder refining slag. This part may be at least 3 wt. %, 4 wt. % or 5 wt. % of the amount of the first metal composition with a high copper content present in the furnace at the end of stage l), preferably at least 10 wt. %, more preferably at least 20 wt. %, even more preferably at least 30 wt. %, and even more preferably at least 40 wt. % of the amount of the first high copper metal composition present in the furnace. The inventors have found that this amount of metal improves the reliable operation of the furnace during this and at least one of the subsequent steps of the process.

In one embodiment of the method in accordance with the present invention, the method further comprises the following step:

m) partially reducing the third solder refining slag, thereby forming a second diluted copper metal composition and a fourth solder refining slag, followed by separating the fourth solder refining slag from the second diluted copper metal composition.

The inventors have found that the third solder refining slag may contain amounts of copper and/or nickel that are still high enough to make a rough solder-type stream from this slag. The authors therefore prefer to include an additional stage m) incomplete recovery as part of the method in accordance with the present invention. We have found that a significant amount of copper and/or nickel present in the third solder refining slag can be easily removed as part of the second diluted copper metal composition formed in step m), while most of the tin and/or lead can be stored as part of the fourth solder refining slag before subjecting the fourth solder refining slag to further processing. Preferably stage m) is performed in such a way that at least 50 wt. % copper present in step m) is recovered as part of the second dilute copper metal composition, more preferably at least 70 wt. %, even more preferably at least 80 wt. %, and even more preferably at least 90 wt. %. Alternatively or additionally, step m) is preferably performed such that at least 50 wt. % tin present in step m) was recovered in the fourth solder refining slag, more preferably at least 70 wt. %, even more preferably at least 80 wt. %, and even more preferably at least 90 wt. %.

In one embodiment of the method according to the present invention, including step m), at the end of step m), the second diluted copper metal composition is only partially removed from the furnace, and part of this metal composition remains in the furnace along with the fourth solder refining slag. This part may be at least 1 wt. %, 2 wt. %, 3 wt. %, 4 wt. % or 5 wt. % of the amount of the second diluted copper metal composition present in the furnace at the end of stage m), preferably at least 10 wt. %, more preferably at least 20 wt. %, even more preferably at least 30 wt. %, and even more preferably at least 40 wt. % of the amount of the second dilute copper metal composition present in the furnace. The inventors have found that this amount of metal improves the reliable operation of the furnace during at least one of the subsequent steps of the process.

In one embodiment of the method in accordance with the present invention, the method further comprises the following step:

n) partially reducing the fourth solder refining slag, thereby forming a second rough solder metal composition and a fifth solder refining slag, followed by separating the second rough solder metal composition from the fifth solder refining slag.

The inventors have found that the fourth solder refining slag is a very suitable feedstock for the recovery of rough solder type material suitable for further processing into higher purity tin and/or lead main products. The inventors have found that in stage n) of incomplete reduction, most of the tin and/or lead present in the furnace can be recovered with the second rough solder metal composition, along with substantially all of the copper and/or nickel present, while most metals having a higher affinity for oxygen under process conditions, such as iron, can be retained as part of the fifth solder refining slag. The inventors have found that the second braze metal composition is suitable for further processing, for example by subjecting this stream to silicon metal treatment as described in DE 102012005401 A1. Alternatively or additionally, this rough solder stream, optionally after an enrichment step to increase the tin and/or lead content, can be further adjusted as described in WO 2018/060202 A1 and the like, and then subjected to distillation and tin recovery and /or lead as high purity metal products as described in the same document.

In one embodiment of the method in accordance with the present invention, the method further comprises the following step:

o) partially reducing the fifth solder refining slag, thereby forming a third lead-tin metal composition and a third waste slag, followed by separating the third waste slag from the third lead-tin metal composition.

The inventors have found it advantageous to provide for an additional reduction step o) after step n) of rough solder production, in particular a partial reduction step for the fifth solder refining slag that was obtained in step n). The inventors have found that more valuable metals can be recovered from this fifth solder refining slag using step o), making the remaining slag even more suitable for use in a valuable end application and/or to dispose of this slag as waste. We have additionally found that the additional reduction step o) is also capable of reducing leachable metals in the slag, such as lead, to sufficiently low levels so that the slag after step o) can be further used as a valuable material, or safely disposed of, all with a very limited number of additional processing steps, and possibly no additional processing steps at all, to reduce the concentration of sensitive metals such as lead and/or zinc.

In one embodiment of the method in accordance with the present invention, the method further comprises the following step:

p) partially oxidizing the third lead-tin metal composition, thereby forming a fourth lead-tin metal composition and a sixth solder refining slag, followed by separating the sixth solder refining slag from the fourth lead-tin metal composition.

The inventors have found that step p) has the advantage that the third lead-tin metal composition recovered in step o) separates on one side into a metal stream in which the copper from step p) is concentrated along with most of the nickel present, and on the other hand to the slag phase, which contains very little copper, but concentrates a significant part of the tin and/or lead present in stage p), together with most of the iron, and also zinc, if present. The inventors have found that this separation has the advantage that the two streams obtained in step p) can be processed separately, and preferably also differently, using steps that are more appropriate for their formulations.

In one embodiment of the method in accordance with the present invention, the method further comprises the following step:

q) recycling at least a portion of the sixth solder refining slag to step d), preferably prior to oxidation of the first liquid bath, and/or adding at least a portion of the sixth solder refining slag to the first liquid bath, and/or recycling at least a portion of the sixth solder refining slag refining slag to step e), preferably before the recovery of the first solder refining slag.

We prefer to recycle the sixth solder refining slag to step d) and/or step e) because this allows the tin and/or lead contained in this slag stream to be recovered into the first rough solder metal composition from step e) or the second metal composition rough solder from step n), while the iron present in the sixth solder refining slag easily enters the second waste slag from step f) without risking iron accumulation in the cycle that is part of the process according to the present invention.

In one embodiment of the method according to the present invention, comprising step p), the method further comprises the following step:

r) recycling at least a portion of the fourth lead-tin metal composition to step l), and/or adding at least a portion of the fourth lead-tin metal composition to the second liquid bath, preferably prior to oxidation of the second liquid bath in step l ).

We prefer to return the fourth lead-tin metal composition to step l) because this metal stream is highly suitable for contacting, together with the first diluted copper metal composition from step d), the third copper refinery slag from step j), which is added to the second liquid bath whereby the third copper refining slag is partially reduced and the two added metal compositions are partially oxidized and an equilibrium can be established where most of the copper present in the furnace along with nickel and some tin and/or lead enters the first high copper metal composition, while any discarded metals (iron, silicon, aluminium) along with a significant portion of the tin and/or lead present become part of the third solder refining slag produced in step l).

In one embodiment of the process according to the present invention comprising step o), step o) comprises adding a second copper-containing fresh feed in step o), preferably before the reduction of the fifth solder refining slag.

The authors have found that the addition of copper in step o) of the reduction provides a significant benefit because copper can act as an excellent extracting agent for any other valuable metals that remain in the fifth solder refining slag after step n), and that this beneficial extraction can be performed without significant loss of copper in the third spent slag which is produced in step o).

We have additionally found that the copper-containing fresh feed that can be added in step o) may contain significant amounts of other valuable metals, in particular zinc, nickel, tin and/or lead. The authors have found that if sufficient copper is provided, that losses, especially tin and/or lead, with the third waste slag can be kept very low and therefore do not compromise the possible further use or direction of this third waste slag and do not create an economically significant loss of precious metals.

The authors have found that a wide range of materials are suitable as copper-containing fresh feed for step o). The inventors prefer, however, that the copper-containing fresh feed for step o) contains only a limited amount, and preferably does not contain combustible substances at all, i.e. substances that readily oxidize under process conditions, for example organic materials such as plastics and/or hydrocarbons, residues fuel or oil, etc., so that the temperature in step o) remains easily controlled.

In one embodiment of the method according to the present invention, including step o), the second copper-containing fresh feed contains ferrous copper and/or spent or discarded copper anode material.

The inventors have found that in step o) a significant amount of black copper, similar in composition to the black copper provided in step a), can be added to extract the higher value metals from the fifth solder refining slag produced in step n) without excessive losses especially valuable metals with the third spent slag from stage o). The inventors have found that the amounts of such black copper from the previous smelting step that can be fed to step o) are very significant, and may even be on the order of the amount of black copper provided in step a) as feed to step b). The inventors have found that the inclusion of step o) in the process according to the present invention significantly increases the ability to process smelting black copper, and therefore to process higher quantities of low quality raw materials, resulting in valuable metals with low cost and therefore high economic potential. The inventors have found that this way of performing step o) has the additional advantage that a significant portion of the black copper from the preceding smelting step can be processed without all the black copper that would have to pass through at least the first step b) of the copper refining sequence. Any metals in the black copper feed stream for step o) which, under process conditions, have a higher oxygen affinity than copper, are likely already removed before the copper from this fresh black copper feed for step o) can enter step b ) and go through the copper refining process sequence of steps b), h) and j).

The inventors have also found that step o) is also very suitable for introducing spent and/or discarded copper anode material. The production of high quality copper usually contains an electrolysis step in which copper is dissolved from the anode into an electrolyte and deposited on the cathode. The anode is usually not consumed completely and is removed as spent copper anode material from the plating bath before the last copper has been dissolved in it. The inventors have found that step o) is very suitable for the introduction of such spent copper anode material. Copper anodes for this copper electrolysis step are usually cast by pouring a suitable amount of anode grade molten copper into a mold and solidifying the copper as it cools. For copper electrolysis to function well, anodes must meet fairly stringent requirements in terms of size and shape. Non-compliant anodes are preferably not used and are discarded copper anode material. The inventors have found that step o) is also very suitable for the introduction of such discarded copper anode material.

The authors prefer to introduce spent and/or rejected copper anode material in solid form with little or no heating. This has the advantage that the melting of this material consumes at least part of the heat of the reactions occurring in step o).

In one embodiment of the process according to the present invention, including step o), step o) comprises adding a sixth reducing agent, preferably before reducing the fifth solder refining slag.

The inventors have found that the sixth reducing agent improves the result of the reduction step o) towards the desired separation of valuable metals into the third lead-tin metal composition and retention of discarded metals in the third spent slag. The inventors have found that the sixth reducing agent may be a gas such as methane or natural gas, but may also be a solid or liquid such as carbon, hydrocarbon, and even aluminum or iron.

In one embodiment of the process according to the present invention, the sixth reducing agent comprises, and preferably is, a metal having, under process conditions, a higher oxygen affinity than tin, lead, copper and nickel, preferably metallic iron, and more preferably scrap iron. The authors prefer to use iron, preferably scrap iron, as the reducing agent due to its high availability under economically very attractive conditions. The inventors have found that the addition of a solid reducing agent may have the additional benefit that the furnace requires less additional heating to maintain or reach the desired temperature. The authors have found that this benefit can be quite large because additional heating by combustion of the fuel using air and/or oxygen may not be required at all to achieve the desired temperature. The authors have additionally found that step o) can further benefit from the addition of silica, as explained above.

We prefer to add in step o) some of the sixth copper and iron rich reducing agent, preferably in the form of a multi-metal material, because this multi-metal material is more readily available on more favorable terms than higher purity tin, higher purity copper, or more iron. high purity. Another suitable material would be electric motors, preferably used electric motors due to their high iron content in the cores and copper windings. The authors found that copper and/or tin can be easily retained in the metal phase and kept from moving to the slag phase, while any iron in this copper-containing fresh feed easily moves to the slag phase as iron oxide, which aids chemical reduction. other metals which, under process conditions, have a lower affinity for oxygen than iron.

In one embodiment of the method according to the present invention, including step n), step n) further comprises adding a fifth reducing agent, preferably before reducing the fourth solder refining slag.

The inventors have found that the fifth reducing agent improves the result of the reduction step n) towards the desired separation of valuable metals into the second rough solder metal composition and retention of discarded metals in the fifth solder refining slag. The inventors have found that the fifth reducing agent may be a gas such as methane or natural gas, but may also be a solid or liquid such as carbon, hydrocarbon, and even aluminum or iron.

In one embodiment of the method according to the present invention, comprising step n), the fifth reducing agent comprises, and preferably is, a metal having, under the conditions of the method, a higher affinity for oxygen than tin, lead, copper and nickel, preferably metallic iron, and more preferably scrap iron. The authors prefer to use iron, preferably scrap iron, as the reducing agent due to its high availability under economically very attractive conditions. The inventors have found that the addition of a solid reducing agent may have the additional benefit that the furnace requires less additional heating to maintain or reach the desired temperature. The authors have found that this benefit can be quite large because additional heating by combustion of the fuel using air and/or oxygen may not be required at all to achieve the desired temperature. The authors have additionally found that stage n) can further benefit from the addition of silica, as explained above.

Preferably the fifth reducing agent contains a small amount of copper and/or Nickel, more preferably less than 1 wt. % copper and nickel together. This has the advantage that little or no additional copper and nickel are introduced into the second braze metal composition, so that the chemical consumption in the subsequent refining step of this braze composition is hardly increased.

In one embodiment of the process according to the invention, comprising step n), the second fresh feed containing Pb and/or Sn is added in step n), preferably before the reduction of the fourth solder refining slag, preferably the second fresh feed containing Pb and/or Sn, containing, and more preferably representing dross, obtained from the subsequent processing of concentrated streams of Pb and/or Sn.

The inventors have found that step n) is also a very suitable position in the process for introducing materials which are rich in tin and/or lead and low in copper and nickel, but which may contain metals which, under process conditions, have a higher affinity for oxygen than tin and lead. Their addition in step n) has the advantage that the tin and/or lead can be easily recovered as part of the second rough solder metal composition and removed from the process, while the so-called "less noble" metals follow the short and direct process path into the third spent slag produced in the subsequent step o).

We have found that step n) is very suitable for recovering tin and/or lead, and optionally antimony and/or arsenic, contained in raw materials or process by-products that are rich in such metals but have a relatively low content of copper and/or nickel. The inventors have found that the second fresh feed containing Pb and/or Sn may additionally contain metals which, under process conditions, have a higher affinity for oxygen than tin and/or lead, such as sodium, potassium, calcium. Such metals may be included, for example, as part of the chemicals used in subsequent steps to clean up a tin and/or lead rich stream, such as the first rough solder metal composition or subsequent derivatives thereof. The inventors have found that step n) is very suitable for recovering valuable metals from the dross by-product formed in one of the purification steps performed as part of the methods disclosed in patent document WO 2018/060202 A1 and the like. Such dross by-product streams typically carry economically significant amounts of tin and/or lead and also contain other metals that may have been introduced as part of the process chemicals.

In one embodiment of the method according to the present invention, comprising step m), the method further comprises the following step:

s) recycling at least a portion of the second diluted copper metal composition formed in step m) to step c), preferably prior to the recovery of the first copper refining slag, and/or recycling at least a portion of the second diluted copper metal composition to step d), preferably before the first lead-tin metal composition is oxidized and/or at least a portion of the second dilute copper metal composition is added to the first liquid bath.

The authors found that no matter which recycling option is chosen to recycle the second dilute copper metal composition, the copper recovered with the second dilute copper metal composition, in addition to any nickel that may be present, is readily recovered in the first dilute copper metal composition, which is formed in step d) and then easily enters the first high copper metal composition which is formed in step l) with which the copper can be recovered from the process, while any tin and/or lead present in of the second diluted copper metal composition can easily be carried into the first solder refining slag formed in step d) and then further downstream can be recovered as part of the first rough solder metal composition formed in step e) with which they can be recovered out of the way.

In one embodiment of the method according to the present invention, including step m), step m) further comprises adding a fourth reducing agent, preferably before reducing the third solder refining slag.

The inventors have found that the fourth reducing agent improves the result of the reduction step m) towards the desired separation of valuable metals into the second dilute copper metal composition and retention of the discarded metals in the fourth solder refining slag. The inventors have found that the fourth reducing agent may be a gas such as methane or natural gas, but may also be a solid or liquid such as carbon, hydrocarbon, and even aluminum or iron.

In one embodiment of the method according to the present invention comprising step m), the fourth reducing agent comprises, and preferably is, a metal having, under the process conditions, a higher oxygen affinity than tin, lead, copper and nickel, preferably iron metal, and more preferably scrap iron.

The authors prefer to use iron, preferably scrap iron, as the reducing agent due to its high availability under economically very attractive conditions. The inventors have found that the addition of a solid reducing agent may have the additional benefit that the furnace requires less additional heating to maintain or reach the desired temperature. The authors have found that this benefit can be quite large because additional heating by combustion of the fuel using air and/or oxygen may not be required at all to achieve the desired temperature. The authors additionally found that stage m) can further benefit from the addition of silica, as explained above.

We prefer to add in step m) some amount of a fourth reducing agent rich in copper and iron, preferably in the form of a multi-metal material, because this multi-metal material is more readily available at more favorable terms than higher purity tin, higher purity copper, or more iron. high purity. Another suitable material would be electric motors, preferably used electric motors due to their high iron content in the cores and copper windings. The authors have found that copper can be easily retained in the metal phase and kept from moving into the slag phase, while any tin, lead, and iron in this copper-containing fresh feed easily moves into the slag phase as their respective oxides, which aids chemical reduction of other metals which, under process conditions, have a lower affinity for oxygen than tin, lead and iron.

In one embodiment of the process according to the present invention, at least one of the process steps comprising separating the metal phase from the slag phase adds some silica, preferably in the form of sand.

The inventors have found that silica promotes the formation of the slag phase, improves the fluidity of the slag, and improves the gravity separation of the metal phase and the slag phase. Without wishing to be bound by any theory, the Authors believe that reducing the viscosity of the slag itself greatly improves phase separation because the metal bubbles formed in the slag phase as a result of chemical reduction move more easily through the slag phase and can thus reach the interface between these two phases, where they can combine with the underlying continuous metal phase. The addition of silica further favorably influences the equilibrium of particular metals between the metal phase and the slag phase, in particular for lead. Silica also increases the acidity of the slag, which further affects the balance in the furnace between the various phases. When the slag contains iron and is removed from the furnace and granulated by contacting the hot liquid slag with water, the addition of silica avoids the risk of iron being present in a form that acts as a catalyst to split the water and hence form hydrogen gas which creates an explosion hazard. The silica also increases the activity of any tin in the slag, causing the SnO ₂ to be reduced to metallic Sn, which goes into the metallic phase. This latter mechanism reduces the amount of Sn that remains in the slag for the same underlying metal composition.

In one embodiment of the process according to the present invention, the black copper produced by the smelting step is added in at least one of steps b), f) and o).

The authors have found that the melting step is very suitable, and even preferred, for the production of any and preferably all black copper compositions, which are used as possible feed and fresh feed for the steps of the method in accordance with the present invention, in particular steps b), h), f ) and/or o). The melting stage offers the advantage of ease of operation and equipment, and is therefore cost effective. The melting step has the additional advantage of being tolerant of raw material quality. The melting stage is capable of receiving feedstocks that are extremely dilute and/or contaminated with a variety of components, as described above herein. As this mixed and/or contaminated raw material is unlikely to have any other end use, it can be supplied on economically very attractive terms. Therefore, the ability to process such raw materials and isolate the valuable metals contained therein is of interest to the operator of the method in accordance with the present invention.

In the smelting furnace, metals are melted, and organics and other combustible materials are burned. Metals having a relatively high affinity for oxygen are converted to their oxides and collected in the low density floating slag phase. Metals having a lower affinity for oxygen remain elemental metals in the denser liquid metal phase at the bottom of the smelter. In the copper production step, the smelting step can be carried out in such a way that most of the iron ends up in the slag, while the copper, tin and lead end up in the metal product, a stream commonly referred to as "black copper". Also, most nickel, antimony, arsenic and bismuth become part of the black copper product.

The inventors have found that the metal product from the melting step can be introduced into the process according to the present invention as a molten liquid, but alternatively can be solidified and cooled, for example by granulation, which allows transportation between different industrial sites, and then introduced into the process up to or after remelting.

In one embodiment of the method according to the present invention, at least one of the first braze metal composition and the second braze metal composition is precleaned using silicon metal to produce a precleaned solder metal composition. A suitable pre-cleaning for such a rough solder metal composition is described in DE 102012005401 A1.

In one embodiment, the method according to the present invention further comprises the step of cooling the first rough solder metal composition and/or the second rough solder metal composition and/or the pre-cleaned solder metal composition to a temperature of at most 825° C. to obtain a bath containing the first floating solder metal. dross, which, under the action of gravity, floats above the first liquid molten phase of the adjusted solder. The inventors have found that this additional downstream process step is able to remove significant amounts of copper and other unwanted metals from the rough solder. More details for this step can be found in patent document WO 2018/060202 A1. We have further found that this cooling step, in combination with some of the subsequent process steps performed on this lead/tin stream, may offer an alternative, at least in part, to the silicon metal pre-retreatment mentioned elsewhere herein. This is advantageous because silicon metal is a rather scarce chemical and reducing and/or eliminating its use can bring significant benefits.

In one embodiment, the method according to the present invention further comprises the step of adding an alkali metal and/or an alkaline earth metal or a chemical compound containing an alkali metal and/or an alkaline earth metal to the first rough solder metal composition and/or to the second rough solder metal composition and/or to the pre-cleaned solder metal composition and/or to the first liquid molten phase of the adjusted solder to form a pool containing a second floating dross that floats above the second liquid molten phase of the adjusted solder under the action of gravity.

In one embodiment, the method in accordance with the present invention further comprises the step of removing the second pop-up dross from the second liquid molten phase of the adjusted solder, thereby forming the second adjusted solder.

In one embodiment, the method in accordance with the present invention further comprises the step of removing the fifth pop-up dross from the first liquid molten phase of the adjusted solder, thereby forming the first adjusted solder.

In one embodiment, the method according to the present invention further comprises the step of distilling the first adjusted solder and/or the second adjusted solder, in which lead (Pb) is removed from the solder by evaporation, and an overhead distillation product and a bottom distillation product are obtained, preferably with distillation in vacuum.

In one embodiment of the method according to the present invention, comprising the step of distilling at least one of the solder streams to remove lead (Pb) from the solder by evaporation and obtain an overhead distillation product and a distillation bottoms product, the distillation bottoms product contains at least 0 .6 wt. % lead. The advantages of this are explained in patent document WO 2018/060202 A1.

In one embodiment of the present invention, at least part of the method is monitored and/or controlled electronically, preferably by a computer program. The inventors have found that controlling the steps of the method according to the present invention by means of electronics, preferably a computer program, offers the advantage of much better processing, with much more predictable results that are closer to the goals of the method. For example, based on temperature measurements, and optionally also pressure and/or level measurements, and/or in combination with the results of chemical analyzes of samples taken from the process streams and/or with real-time analysis results, the control program may operate equipment related to turning on or off electricity, supplying heat or coolant, regulating flow and/or pressure. The inventors have found that such tracking or control is particularly beneficial with stages that are operated continuously, but it may also be beneficial with stages that are operated on a batch or semi-continuous basis. In addition, and preferably, the tracking results obtained during or after the steps in the method according to the present invention are also used to monitor and/or control other steps that are part of the method according to the present invention and/or the methods which are applied before or after the method according to the present invention, as part of a general method within which the method according to the present invention is only a part. Preferably the entire general process is monitored electronically, more preferably by at least one computer program. Preferably the general process is electronically controlled as much as possible.

The authors prefer that computer control also provides for the transfer of data and instructions from one computer or computer program to at least one other computer or computer program, or to a module of the same computer program, for monitoring and / or control in other ways, including, but without limitation, the methods described herein.

We prefer to carry out the specific process steps of the present invention in a top blown rotary converter (TBRC), optionally in a furnace as disclosed in US Pat. No. 3,682,623, see FIG. 3-5 and related description, or in an oven commonly known as a KALDO oven or converter. The inventors particularly prefer to use this type of furnace in those stages where a chemical reaction takes place and/or in which an equilibrium between the molten slag phase and the underlying molten metal phase is desired.

The authors have found that this type of furnace allows the processing of complex materials, materials that produce a large amount of the slag phase, as well as materials with large variations in terms of physical appearance as well as chemical composition. This type of furnace is able to accept as feed slags from other process steps and/or large pieces of hard materials, i.e. raw materials that are much more difficult to introduce into furnaces of other types of construction.

Such furnaces have the advantage that the furnace can be rotated so that more intense contact between solids and liquids and between different liquid phases can be obtained, allowing the desired equilibrium between the phases to be approached and/or achieved more quickly.

Preferably, the rotation speed of the furnace is variable, so that the rotation speed of the furnace can be adapted to the process step carried out in the furnace. Process steps requiring reaction and moving the contents of the furnace towards equilibrium prefer high rotation speed, while other process steps, such as when solid fresh feed is to be melted, may prefer low rotation speed or possibly even no rotation at all.

Preferably, the angle of the furnace is variable, which provides better control of the mixing as well as the reaction kinetics. The variable inclination also provides a better start on solid feed, preferably with a low inclination, until enough sufficiently hot liquid is formed, and therefore more flowable liquid, to keep the remaining solids afloat.

The authors prefer, under specific conditions, to operate the furnace at least intermittently not in the usual mode of rotation, but in the so-called "rocking mode", that is, alternately rotating the furnace in opposite directions only a fraction of a full rotation of 360°. The authors have found that this mode of operation avoids possible extreme loads on the drive equipment of the furnace, which occur when the furnace is fully rotated with the same contents. The authors prefer to use this mode of operation when there is still a relatively large amount of solids in the charge and too little liquid phase to keep these solids afloat, or when the liquid phase in the furnace still has low fluidity, for example because it is still pretty cold.

The authors prefer that the TBRC has a refractory lining, and more preferably this lining has two layers. Preferably, the inner layer of the lining, i.e. the layer in contact with the contents of the furnace, is made of a material that becomes visually lighter at high temperatures of the contents of the furnace during operation, while the material of the underlying layer remains dark when exposed to the internal temperatures of the vessel. This allows you to quickly identify defects in the lining with a simple visual inspection during operation of the furnace.

The outer layer of the lining thus acts as a kind of protective layer. The inventors prefer this protective lining layer to have a lower thermal conductivity than the inner lining layer.

When installing a TBRC lining, the lining being preferably made by stacking individual conical shaped refractory bricks, the Applicants prefer to create a sacrificial layer between the individual linings or bricks, such as a layer of cardboard or roofing. This has the advantage that when the kiln is heated for the first time, this sacrificial layer burns out and disappears, leaving room for thermal expansion of the bricks.

Several steps in the process according to the present invention prefer that the underlying molten metal phase is discharged from the furnace while the floating liquid slag phase is still in the furnace. The authors prefer to release this liquid metal through a drain or outlet in the refractory lining of the furnace. The authors prefer to plug this hole with a sacrificial metal rod during the movements of the furnace during its operation. In order to prepare the release of metal, the Authors prefer to burn this rod while it is above the liquid level in the furnace, and temporarily plug the burnt outlet with a combustible plug, for example, made of cardboard, after which the furnace is rotated to the position of metal release. The authors found that the burn time of the combustible plug provides time for the furnace to rotate to the metal outlet position and pass the outlet through the slag phase.

To heat the furnace with an external heat supply, the authors prefer to use a burner that burns a mixture of fuel and oxygen source, instead of separately introducing fuel and oxygen source into the furnace. The inventors have found that such a mixing burner can be more difficult to operate, but has the advantage that the flame can be directed more precisely to a preferred location within the furnace.

The inventors have found that the ratio of fuel to oxygen source can easily be used to control the redox/oxidation regime within the furnace, and hence to help regulate and/or control the direction of the chemical reactions that must take place within the furnace.

The inventors have found that those steps of the process according to the present invention that introduce cold feedstock can produce dioxins and/or volatile organic compounds (VOCs). The inventors prefer to carry out these process steps in ovens equipped with suitable equipment to capture dioxins and/or VOCs from the exhaust vapors. The inventors have found that the method can be used in such a way that only a subset of stoves need such exhaust treatment equipment, while for other stoves dust collection and/or filtration is sufficient to meet legal emission standards.

The method according to the present invention includes several cases of transferring the liquid molten phase of metal and/or slag from one furnace to another. The authors have found that this transfer is most conveniently performed using transfer buckets. In order to protect the construction materials of the transfer ladles, the Authors prefer to provide these ladles with an internal layer of hard slag coating.

EXAMPLE

The following example shows one preferred embodiment of the present invention. This example is further illustrated in Fig. 1, which shows the flow diagram of the main part of the method in accordance with the present invention. In this part of the process, from a variety of different feedstocks and starting with black copper composition 1, an anode grade refined copper product 9, a high copper content copper metal composition by-product 22, two rough solder metal composition products 18 and 26, and three spent slags 12, 20 and 28.

On FIG. 1 numbers denote the following features of the claims:

1. Feedstock composition of black copper for stage b) (100)

2. Fresh food for stage b) (100)

3. First copper refining slag

4. The first copper-rich metal phase

5. Fresh food for stage h) (200)

6. Second copper refining slag

7. Second copper-rich metal phase

8. Third copper refining slag

9. The third copper-rich metal phase is the anode grade

10. The second metal composition based on lead-tin

11. Second diluted copper metal composition

12. First spent slag

13. The first metal composition based on lead-tin

14. Sixth solder refining slag for the first liquid bath (450) before step d) (500)

15. The first diluted copper metal composition

16. First solder refining slag

17. First fresh food containing Pb and/or Sn for step e) (600)

18. The first metal composition of rough solder

19. Second solder refining slag

20. Second spent slag

21. The fourth metal composition based on lead-tin

22. First metal composition with a high content of copper - part removed from the process

23. Third solder refining slag

24. Fourth solder refining slag

25. Second containing Pb and/or Sn fresh food for stage n) (1000)

26. The second metal composition of the rough solder

27. Fifth solder refining slag

28. Third spent slag

29. The third metal composition based on lead-tin

30. The first metal composition with a high content of copper - part returned to stage b) and/or stage d)

31. Fresh food for stage j) (300)

50. First copper-containing fresh food for stage f) (700)

51. Fresh nutrition for stage p) (1200)

52. Fresh food for the second liquid bath (550) before stage l) (800)

53. Sixth solder refining slag returned to step e) (600)

55. Second copper containing fresh feed for stage o) (1100)

56. Fresh food for stage c) (400)

57. Fresh nutrition for the first liquid bath (450) before step d) (500)

58. Fresh food for stage m) (900)

450 First liquid bath

550 Second liquid bath

100 Process step b)

200 Process step h)

300 Process step j)

400 Process step c)

500 Process step d)

600 Process step e)

700 Process step f)

701 Process step g)

800 Process step l)

801 Recycle stream 30 from step l) to step b) and/or d)

900 Process step m)

901 Process step s) i.e. recycling stream 11 from step m) to step c)

1000 Process step n)

1100 Process step o)

1200 Process step p)

1201 Process step q) - Recycle part of the sixth solder refining slag (14) from step p) to the first liquid bath (450) and/or (53) to step e) (600)

1202 Process step r) - Recycle the fourth lead-tin metal composition (21) from step p) to the second liquid bath (550).

Stage b) (100): The top blown rotary converter (TBRC) used herein as the refining furnace for stage b) (100) was charged with 21345 kg of black copper 1 from the previous smelter, 30524 kg of the first metal composition with high content of copper 30, returned from the subsequent stage l) of the process (800) after the previous cycle of the process, and 86060 kg of fresh feed 2. Fresh feed 2 consisted mainly of bronze, tombac and some raw materials rich in copper but poor in other valuable metals. The compositions and quantities of all the feeds for charging in step b) (100) are shown in Table I. To the feed thus loaded, some amount of silica flux was added in the form of a sand flux, sufficient to obtain the desired phase separation and/or slag flow effects. The feed was melted and/or heated under oxidizing conditions and partly with an oxygen purge during the rotation of the furnace.

Table I Step b)
(100) black copper
1 The first copper-rich metal
thirty Fresh food
2 Loading, t 21.345 30.524 86.060 tons wt. % tons wt. % tons wt. % Cu 16.153 75.68% 28.143 92.20% 68.410 79.49% sn 1.114 5.22% 0.522 1.71% 1.380 1.60% Pb 2.218 10.39% 0.531 1.74% 3.116 3.62% Zn 0.989 4.63% 0.005 0.02% 2,470 2.87% Fe 0.336 1.57% 0.002 0.01% 1.747 2.03% Ni 0.428 2.00% 1.105 3.62% 0.868 1.01% Sb 0.043 0.20% 0.171 0.56% 0.085 0.10% Bi 0.005 0.03% 0.012 0.04% 0.013 0.02% As 0.013 0.06% 0.017 0.06% 0.014 0.02%

Significant amounts of zinc present in the feed were smoked out of the furnace. At the end of the first oxidation step b) (100), the first copper refining slag 3 was tapped and transferred to the slag re-treatment furnace to perform step c) (400). This first copper refining slag 3 contained a lot of lead, tin, zinc and iron. The detailed composition and quantity of this slag 3 as well as the first copper-rich metal phase 4 and the dust generated during step b) (100) are shown in Table II. The first copper rich metal phase 4 was transferred to another TBRC to perform step h) (200).

Table II Step b)
(100) First copper refining slag - 3 First rich in copper
metal phase - 4 Dust Loading, t 27.061 116.371 1.47 tons wt. % tons wt. % tons wt. % Cu 3.231 11.94% 111.367 95.70% 0.221 15.00% sn 1.810 6.69% 1.059 0.91% 0.147 10.00% Pb 3.875 14.32% 1,760 1.51% 0.221 15.00% Zn 3.023 11.17% 0.000 0.00% 0.441 30.00% Fe 2.076 7.67% 0.005 0.00% 0.000 0.00% Ni 1.012 3.74% 1.396 1.20% 0.000 0.00% Sb 0.052 0.19% 0.249 0.21% 0.000 0.00% Bi 0.001 0.00% 0.031 0.03% 0.000 0.00% As 0.006 0.02% 0.038 0.03% 0.000 0.00%

Step h) (200): To the first copper rich metal phase 4 was added 27091 kg of copper rich fresh feed 5 as well as sufficient sand flux to obtain the desired phase separation and/or slag flow effects. This fresh feed 5 consisted of some additional black copper from a previous melt, in addition to copper-rich hard material to lower the furnace temperature. The compositions and amounts of feed streams for filling in stage h) (200) are shown in Table III.

Table III Stage h)
(200) The first copper-rich metal phase - 4 Fresh food
5 Loading, t 116.371 27.091 tons wt. % tons wt. % Cu 111.367 95.70% 23.794 92.48% sn 1.059 0.91% 0.277 1.08% Pb 1,760 1.51% 0.579 2.25% Zn 0.000 0.00% 0.513 1.99% Fe 0.005 0.00% 0.209 0.81% Ni 1.396 1.20% 0.131 0.51% Sb 0.249 0.21% 0.015 0.06% Bi 0.031 0.03% 0.004 0.01% As 0.038 0.03% 0.002 0.01%

Oxidation of the furnace contents was performed by blowing oxygen into the furnace contents. At the end of the second oxidation stage, the second copper refining slag 6 was discharged and transferred to another slag reprocessing furnace to perform stage d) (500). The remaining second copper rich metal phase 7 was transferred to another TBRC to perform step j) (300). The composition and amount of the second copper refining slag 6 and the second copper-rich metal phase 7 are shown in Table IV. As can be seen in Table IV, the metal phase 7 was significantly enriched in copper compared to feed streams 4 and 5 in Table III.

Table IV Stage h)
(200) Second copper refining slag
6 The second copper-rich metal phase - 7 Loading, t 17.230 128.573 tons wt. % tons wt. % Cu 7.161 41.56% 126.573 98.45% sn 1.237 7.18% 0.083 0.06% Pb 2.004 11.63% 0.316 0.25% Zn 0.515 2.99% 0.000 0.00% Fe 0.214 1.24% 0.000 0.00% Ni 0.639 3.71% 0.874 0.68% Sb 0.109 0.63% 0.154 0.12% Bi 0.009 0.05% 0.026 0.02% As 0.007 0.04% 0.033 0.03%

Step j) (300): An additional 22,096 kg of copper-rich fresh feed 31 was added to the second copper rich metal phase 7. The compositions and amounts of all feed feeds in step j) (300) are shown in Table V.

Table V Stage j)
(300) The second copper-rich metal phase - 7 Fresh food
31 Loading, t 128.573 22.096 tons wt. % tons wt. % Cu 126.573 98.45% 20.647 93.44% sn 0.083 0.06% 0.077 0.35% Pb 0.316 0.25% 0.177 0.80% Zn 0.000 0.00% 0.192 0.87% Fe 0.000 0.00% 0.109 0.49% Ni 0.874 0.68% 0.029 0.13% Sb 0.154 0.12% 0.003 0.02% Bi 0.026 0.02% 0.001 0.00% As 0.033 0.03% 0.000 0.00%

The contents of the furnace were purged with oxygen and sufficient sand flux was added at the end of the purging period before tapping the third copper refining slag 8 to obtain the desired phase separation and/or slag flow effects. The remaining metal phase 9 of the anode grade copper was removed from the furnace for further processing, such as electrolytic cleaning. The composition and quantity of the third copper refining slag 8 and anode grade copper 9 are shown in Table VI. As can be seen in Table VI, the metal phase 9 was further enriched in copper compared to feed streams 7 and/or 31 in Table V.

Table VI Stage j)
(300) Third copper refining slag
8 Third Copper Rich Metal Phase - 9 - Anode Grade Loading, t 17.024 134.781 tons wt. % tons wt. % Cu 12.535 73.63% 133.546 99.08% sn 0.138 0.81% 0.022 0.02% Pb 0.465 2.73% 0.025 0.02% Zn 0.192 1.13% 0.000 0.00% Fe 0.109 0.64% 0.000 0.00% Ni 0.375 2.20% 0.542 0.40% Sb 0.099 0.58% 0.057 0.04% Bi 0.006 0.04% 0.020 0.02% As 0.006 0.03% 0.028 0.02%

Stage c) (400): 26710 kg of the first copper refining slag 3 (with the composition shown in Table VII) was introduced into another TBRC used as a slag re-treatment furnace, together with 6099 kg of fresh feed 56 and 11229 kg of the second dilute copper metal phase 11 obtained in step m) (900) in the previous process cycle, and together with 23,000 kg of the second metal phase or lead-tin composition 10 obtained in step f) (700) in the previous process cycle. To this contents of the furnace, 10127 kg of scrap iron was added as a reducing agent. Additionally, some sand flux was added, sufficient to obtain the desired effects of safety, phase separation and/or fluidity of the slag. After completion of filling, the furnace was rotated at a speed in the range of 18-20 rpm. The compositions and quantities of all filling feeds in step c) (400) are shown in Table VII.

Table VII Step c)
(400) First copper refining slag - 3 Fresh food
56 Second diluted copper metal phase - 11 Second metal phase based on Pb-Sn - 10 Loading, t 26.710 6.099 11.229 23,000 tons wt. % tons wt. % tons wt. % tons wt. % Cu 3.189 11.94% 0.987 16.18% 6,960 61.98% 16.665 72.50% sn 1.787 6.69% 0.325 5.32% 2.095 18.66% 1.685 7.33% Pb 3.825 14.32% 0.419 6.87% 0.775 6.90% 2.521 10.97% Zn 2.983 11.17% 0.178 2.92% 0.006 0.05% 0.381 1.66% Fe 2.049 7.67% 1,440 23.61% 0.020 0.18% 1.233 5.36% Ni 0.999 3.74% 0.135 2.21% 1.291 11.50% 0.429 1.87% Sb 0.052 0.19% 0.017 0.28% 0.073 0.65% 0.044 0.19% Bi 0.001 0.00% 0.000 0.00% 0.002 0.02% 0.006 0.02% As 0.006 0.02% 0.000 0.00% 0.003 0.03% 0.011 0.05%

When the recovery of copper, tin, and lead was sufficient, the first lead-tin metal composition 13, dust, and the first spent slag 12 were obtained. The compositions and amounts of these products are shown in Table VIII. The first spent slag 12 was released and removed from the process. The first lead-tin metal composition 13 was transferred to another TBRC to become part of the first liquid bath 450.

Table VIII Step c)
(400) First waste slag
12 The first metal phase based on Pb-Sn - 13 Dust Loading, t 31.287 46.718 1.346 tons wt. % tons wt. % tons wt. % Cu 0.111 0.35% 28.105 60.32% 0.031 2.27% sn 0.074 0.24% 5.645 12.11% 0.170 12.64% Pb 0.156 0.50% 7.176 15.40% 0.276 20.52% Zn 2.372 7.58% 0.568 1.22% 0.612 45.50% Fe 12.049 38.51% 2.047 4.39% 0.010 0.71% Ni 0.012 0.04% 2.834 6.08% 0.002 0.12% Sb 0.000 0.00% 0.184 0.39% 0.002 0.18% Bi 0.000 0.00% 0.008 0.02% 0.000 0.00% As 0.000 0.00% 0.016 0.03% 0.004 0.31%

Step d) (500): To form the first liquid bath 450 to 46718 kg of the first lead-tin metal composition 13 17164 kg of the second copper refining slag 6 (having the composition shown in Table IV) was added along with 9541 kg of fresh feed 57 and 474 kg of the sixth solder refining slag 14 (returned from the subsequent stage p) (1200) in the previous process cycle). Additionally, some sand flux was added, sufficient to obtain the desired phase separation and/or slag flow effects. The compositions and amounts of the components of the first liquid bath 450, which formed the filling for stage d) (500), are shown in Table IX.

Table IX Stage d)
(500) First metal phase based on Pb-Sn
- 13 Fresh food
57 Sixth solder refining slag - 14 Second copper refining slag - 6 Loading, t 46.718 9.541 0.474 17.164 tons wt. % tons wt. % tons wt. % tons wt. % Cu 28.105 60.32% 1.749 22.09% 0.015 3.08% 7.133 41.56% sn 5.645 12.11% 0.484 6.11% 0.021 4.51% 1.232 7.18% Pb 7.176 15.40% 0.677 8.54% 0.060 12.69% 1.996 11.63% Zn 0.568 1.22% 0.308 3.89% 0.025 5.30% 0.513 2.99% Fe 2.047 4.39% 2.675 33.77% 0.134 28.21% 0.213 1.24% Ni 2.834 6.08% 0.209 2.63% 0.002 0.33% 0.637 3.71% Sb 0.184 0.39% 0.028 0.35% 0.000 0.01% 0.108 0.63% Bi 0.008 0.02% 0.000 0.00% 0.000 0.00% 0.009 0.05% As 0.016 0.03% 0.000 0.00% 0.000 0.00% 0.007 0.04%

The mixture of slag and metal phase reacted until the copper and/or nickel concentrations in the slag phase were sufficiently reduced. This reaction caused more tin and lead to go into the slag phase. At this point, the furnace was released from below, thereby removing the first dilute copper metal composition 15 from the furnace. The first solder refining slag 16, along with approximately 1 metric tonne of the remaining first dilute copper phase 15, was transferred to another TBRC for the next step e) (600). The compositions and amounts of both product streams from step 500, except for the 1 metric ton of metal phase that remained with the slag phase, are shown in Table X.

Table X Stage d)
(500) First solder refining
slag - 16 First dilute copper metal phase
- 15 Loading, t 28,200 49.792 tons wt. % tons wt. % Cu 1.047 3.71% 35.387 71.07% sn 1.375 4.87% 5.925 11.90% Pb 5.268 18.68% 4,541 9.12% Zn 1.393 4.94% 0.023 0.05% Fe 5.059 17.94% 0.013 0.03% Ni 0.282 1.00% 3.331 6.69% Sb 0.010 0.04% 0.304 0.61% Bi 0.000 0.00% 0.017 0.03% As 0.000 0.00% 0.022 0.05%

The first diluted copper metal phase 15 from step d) contained approximately 0.08 wt. % silver (Ag) and 0.03 wt. % sulfur.

Step e) (600): 14987 kg of the first lead and tin containing fresh feed 17 was added to the first solder refining slag 16 before this mixture was reconstituted in step e) (600). Recovery was carried out by adding 8017 kg of scrap iron as a reducing agent. Additionally, in step e) (600), 8650 kg of the sixth solder refining slag 53, obtained in the subsequent process step p) (1200) of the previous process cycle, was added to the furnace in addition to some sand flux sufficient to obtain the desired separation effects. phases and/or fluidity of the slag. The compositions and amounts of all feeds forming the feed for stage e) (600) are shown in Table XI.

Table XI Stage e)
(600) First solder refining slag - 16 First Pb+Sn Fresh Meal - 17 Sixth solder refining slag - 53 First dilute copper metal phase - 15 Loading, t 28,200 14.987 8,650 1,000 tons wt. % tons wt. % tons wt. % tons wt. % Cu 1.047 3.71% 1.361 9.08% 0.266 3.08% 0.711 71.07% sn 1.375 4.87% 4.184 27.92% 0.390 4.51% 0.119 11.90% Pb 5.268 18.68% 7.738 51.63% 1.098 12.69% 0.091 9.12% Zn 1.393 4.94% 0.043 0.29% 0.458 5.30% 0.000 0.05% Fe 5.059 17.94% 0.106 0.71% 2,440 28.21% 0.000 0.03% Ni 0.282 1.00% 0.011 0.07% 0.029 0.33% 0.067 6.69% Sb 0.010 0.04% 0.298 1.99% 0.001 0.01% 0.006 0.61% Bi 0.000 0.00% 0.002 0.01% 0.000 0.00% 0.000 0.03% As 0.000 0.00% 0.000 0.00% 0.000 0.00% 0.000 0.05%

During this stage of incomplete reduction, a significant amount of zinc evaporated from the furnace in the form of smoke. Recovery was stopped when the concentration of Sn in the slag phase reached approximately the target level. At this point, the furnace was lowered again to remove the first rough solder metal composition 18 from the process. The first rough solder metal composition 18 was further processed into lead and tin main products. The second solder refining slag 19 was transferred to another TBRC for further processing in step f) (700). The compositions and quantities of the first draft solder metal 18, the second solder refining slag 19, and the dust obtained in step e) (600) are shown in Table XII.

Table XII Stage e)
(600) The first metal composition of rough solder - 18 Second solder refining slag - 19 Dust Loading, t 23.132 36.667 1.551 tons wt. % tons wt. % tons wt. % Cu 3.256 13.53% 0.116 0.39% 0.016 1.06% sn 5.389 22.40% 0.778 2.60% 0.150 9.64% Pb 13.224 54.97% 0.652 2.18% 0.318 20.52% Zn 0.087 0.36% 1.106 3.70% 0.706 45.50% Fe 0.282 1.17% 15.003 50.20% 0.011 0.71% Ni 0.354 1.47% 0.032 0.11% 0.002 0.12% Sb 0.311 1.29% 0.002 0.01% 0.003 0.18% Bi 0.002 0.01% 0.000 0.00% 0.000 0.00% As 0.000 0.00% 0.000 0.00% 0.000 0.03%

Step f) (700): A further reduction step was performed on the second solder refining slag 19 by adding 1207 kg of scrap iron as a reducing agent. Additionally, in step f) (700), 22,234 kg of first copper-rich fresh feed 50 and some sand flux sufficient to obtain the desired safety, phase separation and/or slag flow effects were added. This fresh feed 50 consisted of some additional black copper from a previous melt, in addition to some of the slag materials left over from other process steps. The compositions and quantities of all filling feeds in step f) (700) are shown in Table XIII.

Table XIII Step f)
(700) Second solder refining slag - 19 containing Cu
fresh food - 50 Loading, t 36.667 22.234 tons wt. % tons wt. % Cu 0.116 0.39% 16.630 75.95% sn 0.778 2.60% 1.003 4.58% Pb 0.652 2.18% 2.052 9.37% Zn 1.106 3.70% 1.010 4.61% Fe 15.003 50.20% 0.509 2.32% Ni 0.032 0.11% 0.405 1.85% Sb 0.002 0.01% 0.042 0.19% Bi 0.000 0.00% 0.005 0.03% As 0.000 0.00% 0.011 0.05%

When the amount of Cu, Sn and Pb in the slag was reduced to at most 0.50% each, a second lead-tin metal phase 10 and a second spent slag 20 were obtained. Their compositions and amounts are shown in Table XIV. The second spent slag 20 was released and removed from the process. The second lead-tin metal composition 10 was passed to step c) (400) of the next process cycle before the recovery of the first copper refining slag (3).

Table XIV Step f)
(700) Second metal phase based on Pb-Sn - 10 Second waste slag
20 Loading, t 23,000 37.523 tons wt. % tons wt. % Cu 16.665 72.50% 0.115 0.31% sn 1.685 7.33% 0.090 0.24% Pb 2.521 10.97% 0.188 0.50% Zn 0.381 1.66% 1.726 4.60% Fe 1.233 5.36% 15.384 41.00% Ni 0.429 1.87% 0.010 0.03% Sb 0.044 0.19% 0.000 0.00% Bi 0.006 0.02% 0.000 0.00% As 0.011 0.05% 0.000 0.00%

Stage l) (800): 17024 kg of the third copper refining slag 8 (having the composition shown in Table VI) was loaded into the TBRC used as the slag re-treatment furnace, together with 14920 kg of copper-rich fresh feed 52 and 49792 kg of the first diluted copper metal phase 15 obtained in step d) (500). Additionally, some sand flux was added, sufficient to obtain the desired phase separation and/or slag flow effects. These materials were melted together with the fourth lead-tin metal phase 21 (20665 kg) obtained in the subsequent process step p) (1200) in the previous process cycle. These feed streams together constituted the second liquid bath 550. When filling and melting were completed, the furnace was rotated at 20 rpm. The compositions and quantities of all types of feed for charging the slag reworking furnace at stage l) (800) are shown in Table XV.

Table XV Stage l)
(800) Fourth metal phase based on Pb-Sn - 21 Fresh food
52 First diluted copper metal phase - 15 Third copper
refining slag - 8 Loading, t 20.665 14.920 49.792 17.024 tons wt. % tons wt. % tons wt. % tons wt. % Cu 16.483 79.76% 3.985 30.10% 35.387 71.07% 12.535 73.63% sn 1.882 9.11% 0.610 4.61% 5.925 11.90% 0.138 0.81% Pb 1.643 7.95% 3.104 23.45% 4,541 9.12% 0.465 2.73% Zn 0.019 0.09% 0.792 5.98% 0.023 0.05% 0.192 1.13% Fe 0.012 0.06% 1.363 10.29% 0.013 0.03% 0.109 0.64% Ni 0.533 2.58% 0.316 2.39% 3.331 6.69% 0.375 2.20% Sb 0.063 0.31% 0.043 0.33% 0.304 0.61% 0.099 0.58% Bi 0.006 0.03% 0.000 0.00% 0.017 0.03% 0.006 0.04% As 0.011 0.05% 0.000 0.00% 0.022 0.05% 0.006 0.03%

This mixture reacted, optionally further partially oxidized with an oxygen purge, until the concentrations of copper and nickel in the slag reached their target values. At this point, the furnace was lowered to remove 64,500 kg of the first high copper metal composition (streams 22 and 30 together) from the third solder refining slag 23. The third solder refining slag 23, along with approximately 6 metric tons of the first high copper phase metal the copper content that remained with the slag was transferred to another TBRC for further processing at stage m) (900). The compositions and quantities of the product streams at the end of stage l) (800) are shown in Table XVI, and this time include 6 metric tons of the metal phase which remained with the slag phase.

Table XVI Stage l)
(800) The first metal phase with a high content of Cu
22+30 Third solder refining slag
23 Loading, t 70,500 39.276 tons wt. % tons wt. % Cu 59.469 92.20% 3.182 8.10% sn 1.103 1.71% 7.317 18.63% Pb 1.122 1.74% 8.515 21.68% Zn 0.011 0.02% 1.013 2.58% Fe 0.004 0.01% 1.496 3.81% Ni 2.335 3.62% 1,980 5.04% Sb 0.362 0.56% 0.114 0.29% Bi 0.026 0.04% 0.000 0.00% As 0.036 0.06% 0.000 0.00%

30,524 kg of the first high copper metal composition were introduced into the copper refining furnace as stream 30 to start a new stage b) (100) of the next cycle. An additional 33,976 kg were removed from the process as stream 22 for further processing.

Stage m) (900): After removing (30524 kg + 33976 kg =) 64500 kg of the first metal phase with a high content of copper (22 + 30) from the furnace, the contents of the furnace were transferred to another TBRC for further processing in stage m) (900 ). A mixture of 39276 kg of the third solder refining slag 23 and 6 tons of metal having the composition of the first high copper metal composition was partially reduced in step m) (900). Scrap iron was introduced as a reducing agent. Additionally, in stage m) some amount of sand flux was added, sufficient to obtain the desired effects of phase separation and/or fluidity of the slag, as well as a small amount (37 kg) of fresh feed 58. Compositions and quantities of all feeds forming the charge for stage m) (900) are shown in Table XVII.

Table XVII Stage m)
(900) Third solder refining slag - 23 Fresh food
58 Metal phase left with slag (23) Loading, t 39.276 0.037 6,000 0 tons wt. % tons wt. % tons wt. % Cu 3.182 8.10% 0.001 2.38% 5.532 92.20% sn 7.317 18.63% 0.001 3.31% 0.103 1.71% Pb 8.515 21.68% 0.004 10.88% 0.104 1.74% Zn 1.013 2.58% 0.002 5.94% 0.001 0.02% Fe 1.496 3.81% 0.010 27.53% 0.000 0.01% Ni 1,980 5.04% 0.000 0.22% 0.217 3.62% Sb 0.114 0.29% 0.000 0.00% 0.034 0.56% Bi 0.000 0.00% 0.000 0.00% 0.002 0.04% As 0.000 0.00% 0.000 0.00% 0.003 0.06%

The reduction step m) (900) was stopped when the concentrations of copper and nickel in the slag phase decreased sufficiently. At this point, the furnace was lowered to remove 11229 kg of the second dilute copper metal composition 11 for further processing in step c) (400) of the next process cycle. The fourth solder refining slag 24, together with approximately 1400 kg of metal having the composition of the second diluted copper metal phase 11, was transferred to another TBRC to perform step n) (1000). The compositions and total amounts of the second dilute copper metal phase or composition 11 and the fourth solder refining slag 24 are shown in Table XVIII, where 1400 kg of the metal phase that remains with the slag phase is included in the total amount of the second dilute copper metal phase 11.

Table XVIII Stage m)
(900) Second diluted copper metal phase - 11 Fourth solder refining slag - 24 Loading, t 12.629 41.342 tons wt. % tons wt. % Cu 6,960 61.98% 1.389 3.36% sn 2.095 18.66% 5.069 12.26% Pb 0.775 6.90% 7.743 18.73% Zn 0.006 0.05% 1.009 2.44% Fe 0.020 0.18% 9.037 21.86% Ni 1.291 11.50% 0.752 1.82% Sb 0.073 0.65% 0.066 0.16% Bi 0.002 0.02% 0.000 0.00% As 0.003 0.03% 0.000 0.00%

The second diluted copper metal phase 11 from stage m) contained approximately 0.11 wt. % silver (Ag) and 0.01 wt. % sulfur.

Step n) (1000): After 11229 kg of the second dilute copper phase 11 was discharged from the furnace, the remaining contents of the furnace were transferred to another TBRC for step n) (1000). 11789 kg of the second lead and tin fresh feed 25 was added in step n) (1000) and the contents of the furnace were further reconstituted. Recovery was accomplished by adding 9692 kg of scrap iron as a reducing agent along with enough sand flux to produce the desired phase separation and/or slag flow effects. The compositions and quantities of all foods for stage n) (1000) are shown in Table XIX.

Table XIX Stage n)
(1000) Fourth solder refining slag - 24 Fresh food
25 Second diluted copper metal phase - 11 Loading, t 41.342 11.789 1,400 tons wt. % tons wt. % tons wt. % Cu 1.389 3.36% 0.728 6.18% 0.868 61.98% sn 5.069 12.26% 1.864 15.81% 0.261 18.66% Pb 7.743 18.73% 8,790 74.56% 0.097 6.90% Zn 1.009 2.44% 0.019 0.16% 0.001 0.05% Fe 9.037 21.86% 0.070 0.59% 0.003 0.18% Ni 0.752 1.82% 0.003 0.02% 0.161 11.50% Sb 0.066 0.16% 0.074 0.63% 0.009 0.65% Bi 0.000 0.00% 0.037 0.32% 0.000 0.02% As 0.000 0.00% 0.000 0.00% 0.000 0.03%

The partial reduction stage was stopped when the concentration of tin in the slag phase reached approximately the target level. At this point, the furnace was lowered again to remove the second rough solder metal composition 26 from the furnace, leaving only the fifth solder refining slag 27 in the furnace. The second rough solder metal composition 26 was further processed into lead and tin main products. The fifth solder refining slag 27 was transferred to another TBRC to perform step o) (1100). The compositions and quantities of the second draft solder metal 26 and the fifth solder refining slag 27 are shown in Table XX.

Table XX Stage n)
(1000) Second raw solder
26 Fifth solder refining slag
27 Loading, t 23.080 41.956 tons wt. % tons wt. % Cu 2.934 10.57% 0.054 0.13% sn 6.245 22.49% 0.975 2.32% Pb 16.080 57.90% 0.550 1.31% Zn 0.000 0.00% 1.032 2.46% Fe 1.363 4.91% 17.373 41.41% Ni 0.895 3.22% 0.021 0.05% Sb 0.149 0.54% 0.000 0.00% Bi 0.038 0.14% 0.000 0.00% As 0.000 0.00% 0.000 0.00%

Step o) (1100): An additional reduction step was performed on the fifth solder refining slag 27 by adding 922 kg of scrap iron thereto as a reducing agent along with 23735 kg of copper-rich fresh feed 55 and some sand flux sufficient to obtain the desired effects. safety, phase separation and/or slag flowability. The second copper-containing fresh feed 55 consisted mainly of additional black copper from the previous smelt. The compositions and amounts of all types of nutrition for stage o) (1100) are shown in Table XXI.

Table XXI Stage o)
(1100) Fifth solder refining slag
27 Cu-Containing Fresh Nutrition
55 Loading, t 41.956 23.735 tons wt. % tons wt. % Cu 0.054 0.13% 15.456 67.27% sn 0.975 2.32% 0.997 4.34% Pb 0.550 1.31% 2.022 8.80% Zn 1.032 2.46% 1.097 4.77% Fe 17.373 41.41% 1.603 6.98% Ni 0.021 0.05% 0.391 1.70% Sb 0.000 0.00% 0.040 0.17% Bi 0.000 0.00% 0.005 0.02% As 0.000 0.00% 0.011 0.05%

Recovery continued until an acceptable quality of the spent slag was obtained. When this goal was achieved, a third lead-tin metal phase 29 and a third spent slag 28 were obtained, the compositions and quantities of which are shown in Table XXII. The third spent slag 28 was released and removed from the process. The third lead-tin metal composition 29 was transferred to the TBRC for step p) (1200).

Table XXII Stage o)
(1100) The third metal phase based on Pb-Sn - 29 Third spent slag
28 Loading, t 22,300 45.542 tons wt. % tons wt. % Cu 15.446 69.56% 0.155 0.34% sn 1.923 8.66% 0.069 0.15% Pb 2.417 10.88% 0.205 0.45% Zn 0.347 1.56% 1.812 3.98% Fe 1.598 7.20% 18.522 40.67% Ni 0.406 1.83% 0.015 0.03% Sb 0.041 0.18% 0.000 0.00% Bi 0.005 0.02% 0.000 0.00% As 0.011 0.05% 0.000 0.00%

Step p) (1200): To the third lead-tin metal composition 29, 5204 kg of fresh feed 51 was added along with some sand flux sufficient to produce the desired phase separation and/or slag flow effects. Then, by partial oxidation, most of the iron and zinc were oxidized and transferred from the metal phase to the slag phase. The compositions and quantities of the products of this oxidation step p) (1200) are shown in Table XXIII.

Table XXIII Stage p)
(1200) The third metal phase based on Pb-Sn - 29 Fresh food
51 Loading, t 22,300 5.204 tons wt. % tons wt. % Cu 15.446 69.56% 1.402 32.04% sn 1.923 8.66% 0.368 8.42% Pb 2.417 10.88% 0.386 8.83% Zn 0.347 1.56% 0.156 3.56% Fe 1.598 7.20% 0.989 22.61% Ni 0.406 1.83% 0.158 3.61% Sb 0.041 0.18% 0.023 0.54% Bi 0.005 0.02% 0.000 0.01% As 0.011 0.05% 0.000 0.00%

When the oxidation of iron and zinc was sufficiently successful, a fourth lead-tin metal composition 21 and a sixth solder refining slag 14 were obtained, the compositions and quantities of which are shown in Table XXIV. The sixth solder refining slag 14 was discharged and added at least partially as stream 14 to the first liquid bath (450) and/or at least partially as stream 53 in step e) (600) of the next process cycle. The fourth lead-tin metal composition 21 was transferred to another TBRC in order to become part of the second liquid bath 550 and also to perform step l) (800) in the next process cycle.

Table XXIV Stage p)
(1200) Fourth metal phase based on Pb-Sn - 21 Sixth solder refining slag
14 Loading, t 20.665 9.124 tons wt. % tons wt. % Cu 16.483 79.76% 0.281 3.08% sn 1.882 9.11% 0.411 4.51% Pb 1.643 7.95% 1.158 12.69% Zn 0.019 0.09% 0.483 5.30% Fe 0.012 0.06% 2.573 28.21% Ni 0.533 2.58% 0.030 0.33% Sb 0.063 0.31% 0.001 0.01% Bi 0.006 0.03% 0.000 0.00% As 0.011 0.05% 0.000 0.00%

All process steps 100-1200 dealing with molten metal and/or slag phases proceed at a temperature in the range of 1100-1250°C. Depending on the purpose of the stage, its operating temperature may preferably be close to the upper or lower end of this temperature range.

The authors found that the embodiment of the method described in this Example can be performed on a limited number of TBRC furnaces. The inventors were able to carry out this process in only 8 ovens, several of which are preferably TBRC ovens. We prefer to carry out this process in only 6 ovens, more preferably in only 5 ovens, even more preferably in only 4 ovens, and even more preferably in only 3 ovens.

Now, after fully describing this invention, it should be clear to those skilled in the art that the present invention can be carried out within a wide range of claimed parameters without departing from its scope defined by the claims.

Claims (33)

1. The method of co-production of copper metal melt and solder melt from low-quality metal raw materials, containing the following stages, in which: a) provide composition (1) black copper containing at least 50 wt. % copper together with at least 1.0 wt. % tin and at least 1.0 wt. % lead b) partially oxidizing (100) the black copper composition (1), thereby forming a first copper-rich metal phase (4) as a copper metal melt and a first copper refining slag (3), both of which are liquid molten phases, and then separating the first copper refining slag (3) from the first copper-rich metal phase (4), c) partially reducing (400) the first copper refining slag (3), thereby forming a first lead-tin metal composition (13) as a solder melt and a first spent slag (12), both of which are liquid molten phases, and then separating the first spent slag (12) from the first metal composition (13) based on lead-tin, forming the basis for the first liquid bath (450), whereby the total content of the furnace in step c) (400) contains an amount of copper that is at least 1.5 times greater than the sum of Sn and Pb present, and whereby the first spent slag (12) contains at most 20 wt. % in the sum of copper, tin and lead. 2. The method according to p. 1, further comprising the following stage, in which: d) partially oxidize (500) the first liquid bath (450), thereby forming the first dilute copper metal composition (15) and the first solder refining slag (16), then separating the first solder refining slag (16) from the first diluted copper metal composition ( 15). 3. The method of claim 2, further comprising the step of: e) partially reducing (600) the first solder refining slag (16), thereby forming the first rough solder metal composition (18) and the second solder refining slag (19), then separating the second solder refining slag (19) from the first metal composition (18 ) rough solder. 4. The method according to p. 3, further comprising the following stage, in which: f) partially reducing (700) the second solder refining slag (19), thereby forming a second lead-tin-based metal composition (10) and a second waste slag (20), then separating the second waste slag (20) from the second metal composition ( 10) based on lead-tin. 5. The method according to any one of paragraphs. 1-4, further comprising the following step, wherein: h) partially oxidizing (200) the first copper-rich metal phase (4), thereby forming a second copper-rich metal phase (7) and a second copper refining slag (6), then separating the second copper refining slag (6) from the second copper-rich metal phase phase (7). 6. The method of claim 5, further comprising the step of: i) adding at least a part of the second copper refining slag (6) to the first liquid bath (450) and/or adding at least a part of the second copper refining slag (6) in step d) (500). 7. The method according to claim 5 or 6, further comprising the following steps, in which: j) partially oxidizing (300) the second copper-rich metal phase (7), thereby forming a third copper-rich metal phase (9) and a third copper refining slag (8), then separating the third copper refining slag (8) from the third copper-rich metal phase phases (9), k) adding at least a portion of the third copper refining slag (8) to the first diluted copper metal composition (15), thereby forming a second liquid bath (550), and/or adding at least a portion of the third copper refining slag (8) on step l) (800); l) partially oxidize (800) the second liquid bath (550), thereby forming the first metal composition (22) with a high copper content and the third solder refining slag (23), then separating the third solder refining slag (23) from the first metal composition ( 22) with high copper content. 8. The method of claim 7, further comprising the step of: m) partially reducing (900) the third solder refining slag (23), thereby forming a second diluted copper metal composition (11) and a fourth solder refining slag (24), then separating the fourth solder refining slag (24) from the second diluted copper metal composition (eleven). 9. The method of claim 8, further comprising the step of: n) partially reducing (1000) the fourth solder refining slag (24), thereby forming the second rough solder metal composition (26) and the fifth solder refining slag (27), then separating the second rough solder metal composition (26) from the fifth solder refining slag (27). 10. The method of claim 9, further comprising the step of: o) partially restore (1100) the fifth solder refining slag (27), thereby forming the third metal composition (29) based on lead-tin and the third waste slag (28), then separate the third waste slag (28) from the third metal composition ( 29) based on lead-tin. 11. The method according to any one of paragraphs. 1-10, wherein black copper is added in at least one of steps b), f) and o), the black copper being produced by a melting step. 12. The method according to any one of paragraphs. 1-11, wherein at least one of the first rough solder metal composition (18) and the second rough solder metal composition (26) is pre-cleaned using silicon metal to produce a pre-cleaned solder metal composition. 13. The method according to any one of paragraphs. 1-12, further comprising the step of cooling the first rough solder metal composition (18) and/or the second rough solder metal composition (26) and/or the pre-cleaned solder metal composition to a temperature of at most 825°C to form a bath, containing the first floating dross, under the action of gravity floating over the first liquid molten phase of the adjusted solder. 14. The method according to any one of paragraphs. 3-13, further comprising the step of adding an alkali metal and/or an alkaline earth metal, or a chemical compound containing an alkali metal and/or an alkaline earth metal, to the first metal composition (18) of the rough solder and/or to the second metal composition (26 ) of the rough solder and/or to the pre-cleaned solder metal composition and/or to the first liquid molten phase of the adjusted solder to form a pool containing a second floating dross floating by gravity above the second liquid molten phase of the adjusted solder. 15. The method of claim 14, further comprising removing the second floating dross from the second liquid molten phase of the adjusted solder, thereby forming a second adjusted solder. 16. The method according to any one of paragraphs. 13-15, further comprising removing the first floating dross from the first liquid molten phase of the adjusted solder, thereby forming the first adjusted solder. 17. The method according to claim 15 or 16, further comprising the step of distilling the first adjusted solder and/or the second adjusted solder, wherein lead (Pb) is removed from the solder by evaporation, and an overhead distillation product and a bottom distillation product are obtained, preferably by vacuum distillation.

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