RU2820617C1 - Method of extracting metals from electronic scrap - Google Patents

Abstract

FIELD: processing of secondary raw materials.

SUBSTANCE: invention relates to extraction of metals of 8–14th groups from electronic scrap. Method involves providing and melting a mixture containing electronic scrap in a melting reactor to obtain a first melt containing a first metal phase and a first slag phase. First slag phase is separated from the melting reactor and the remaining first metal phase is refined by means of an oxygen-containing gas to obtain a second copper-rich slag phase. Further, refined first metal phase is separated from melting reactor, adding the following mixture containing electronic scrap to the remaining second copper-rich slag phase and repeating the listed steps.

EFFECT: improved extraction of metals from electronic scrap and power saving.

14 cl, 1 ex

Description

The invention relates to methods for processing secondary raw materials, in particular to the extraction of metals of groups 8-14 from electronic scrap.

Such methods are in principle known in the prior art. Thus, on the Internet at https:\\www.totalmateria.com you can find the article “Ausmelt/lsasmelt Matte Smelting: Part One”, which describes a method for reusing copper-containing waste. Specifically, this method provides that such waste is loaded from above into a cylindrical furnace body and oxygen-enriched air is supplied to it inside the furnace body, introduced into the furnace from above using an upper lance. Thus, the loaded waste is melted and a metal phase is formed in the furnace with a floating slag phase. These two heterogeneous phases are released together regularly from the housing. The separation of the metal phase, which has a high copper content, from the slag phase is carried out only outside the cylindrical furnace body.

Chinese patent application CN 108224433 also discloses a method for reusing electronic scrap to recover copper in particular. This method requires that the electronic scrap as feed material is first weighed, mixed and crushed before it is then loaded into a preheated rotary kiln. In the furnace, oxygen and gaseous fuel are supplied to the electronic scrap. The feed material is then melted into a metal phase and a slag phase. After treatment by oxygen injection, the metal phase and the slag phase are released separately.

European patent application EP 1 609 877 A1 discloses a method for periodically enriching metal-containing waste, in particular also such as electronic scrap, in a rotating reactor. Loadable material, i.e. In particular, electronic scrap mainly consists of fractions of a size that allows continuous loading during operation. In the reactor, the material is melted so that a enriched product is created substantially free of any organic matter since the original organic fraction contained in the feed material is burned during melting.

Based on this prior art, it appears that there is still a need for an improved method for recovering metals from electronic scrap.

Therefore, the basis of the present invention is to propose a method for extracting metals of groups 8-14, improved compared to the prior art, in particular a method according to which at least one of the metals of groups 8-14 is quantitatively extracted from loaded electronic scrap groups.

According to the invention, this problem is solved thanks to a method with the features of paragraph 1 of the claims.

Additional preferred embodiments of the invention are given in the dependent claims. The features listed individually in the dependent claims may be combined with each other in a technologically rational manner and may define additional embodiments of the invention. In addition, the features given in the claims are clarified and explained in more detail in the description, which presents additional preferred embodiments of the invention.

The method proposed by the invention for extracting metals of groups 8-14, preferably groups 8-11 and 14 and, in particular, blister copper, includes the following steps:

i) providing and melting the feed mixture containing the electronic scrap in the melting reactor so as to form a first melt containing a first metal phase and a first slag phase;

ii) separating the first slag phase from the melting reactor;

iii) refining the remaining first metal phase by means of an oxygen-containing gas, optionally adding copper-containing waste, so as to form a second copper-rich slag phase;

iv) if necessary, separating the second slag phase and repeating step iii);

v) separating the refined first metal phase from the smelting reactor and

vi) adding the next feed mixture containing the electronic scrap to the remaining second copper-rich slag phase and repeating steps i) to vi) of the process.

Surprisingly, the blister copper present in the copper-rich second slag phase and accumulated as copper oxide in the second slag phase during refining/converting, as a result of the reducing conditions existing in the smelting reactor, during the melting of the next charge or, respectively, the next charged mixture can then be converted into a new first metal phase and extracted directly from it. Thus, as a result of continuous continuation of the process, only slag phases are obtained that are largely depleted in copper. Thus, due to this in situ recovery of oxidized copper, the resulting metal phase has an increased blister copper content. In addition, unexpectedly, it turned out that as a result of the repeated use of the still liquid residual slag or, accordingly, a second copper-enriched slag phase, the entire process has an improved energy balance, and, thanks to the chemically bound oxygen of the copper oxide of the residual slag, the ongoing combustion reaction is maintained with each subsequent loaded mixture.

To obtain a slag that is as liquid and thus not too viscous as possible, the entire process is carried out at a temperature of at least 1150°C, more preferably at a temperature of at least 1200°C, even more preferably at a temperature of at least 1225°C and most preferably at a temperature of 1250°C. However, the process temperature should not exceed the maximum temperature determined by the characteristics of the technological equipment used. For this reason, the maximum process temperature is 1400°C, preferably 1375°C, more preferably 1350°C and most preferably 1325°C.

The method according to the invention is intended for pyrometallurgical processing of electronic scrap. Accordingly, the loaded mixture can in principle contain up to 100 wt. % electronic scrap.

In the context of the present invention, the term "electronic scrap" refers to used electronic equipment, as defined in accordance with EU Directive 2002/96/EC. The categories of equipment covered by this Directive relate to whole and/or (partially) disassembled components of a range including large domestic appliances, small household appliances, information technology and telecommunications equipment, consumer electronics, lighting fixtures, electrical and electronic tools (excluding stationary industrial large instruments), electrical toys, as well as sports and recreational equipment, medical equipment (excluding implanted and contaminated products), monitoring and control devices, and automatic dispensing devices. For individual products belonging to the relevant device categories, reference is made to Annex IB of that Directive.

In addition, the term "electronic scrap" also includes waste and/or by-products resulting from the processing of electronic scrap.

Electronic scrap may be present in the feed mixture in the form of separate fractions and/or mixtures of appropriate components.

If necessary, copper-containing waste may be added to the process in step iii) for cooling purposes. In the context of the present invention, the term "copper-containing waste" means any copper-containing waste having a significant proportion of copper by mass and not covered by said EU Directive 2002/96/EC, such as, for example, copper scrap metal, copper gutters and/or dry copper-containing slurries and /or dust resulting from the manufacture and/or processing of copper and/or copper alloys.

Electronic scrap essentially contains organic substances in the form of hydrocarbon-containing components, in particular such as plastic materials, as well as metal components, in particular such as elements selected from the range including iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel , palladium, platinum, copper, silver, gold, zinc, cadmium, mercury, aluminum, gallium, indium, lead and/or tin, and, if necessary, antimony, titanium and/or yttrium.

However, the content of organic substances in the form of hydrocarbon-containing components in the charged mixture should not be too low, since otherwise a sufficient combustion reaction will not occur. Therefore, the proportion of hydrocarbon-containing components in the electronic scrap or in the charge mixture is preferably at least 5.0 wt. %, more preferably at least 10.0 wt. %. With regard to the maximum content, the electronic scrap or the charged mixture is limited, and therefore the maximum content is preferably no more than 80.0 wt. %, more preferably not more than 70.0 wt. %, even more preferably not more than 60.0 wt. % and most preferably no more than 50.0 wt. %.

If the available e-scrap does not have the desired proportion of organics and thus the required heating value, a target amount of conventional fuels can be added to the feed mixture. In this case, conventional fuels include, for example, coal, coke, as well as flammable gases such as natural gas, propane, hydrogen or other gases known to those skilled in the art.

The addition of solid and/or gaseous fuels may be accomplished by means of a charging device, such as a lance, projecting into the interior of the melting reactor, or by means of one or a plurality of lances.

Melting of the loaded mixture according to step i) is carried out, as a rule, in the presence of atmospheric oxygen. As a result of the addition of atmospheric oxygen, optionally in the form of oxygen-enriched air or in the form of an oxygen-containing gas continuously introduced into the melting reactor during the melting process, combustion of hydrocarbons from the charged feed mixture occurs. In this case, combustion and thus heat generation is specifically controlled by the added amount of oxygen. In principle, it is believed that the higher the proportion of hydrocarbons in the feed mixture, the lower the oxygen content of the added combustion air can be. However, due to the composition of the air, the indicated oxygen content is always at least 20.5 vol. %.

With an insignificant proportion of hydrocarbons in the loaded mixture, the melting process can be carried out with an oxygen content in the combustion air of up to 100 vol. %.

Advantageously, step i) of the method according to the invention is maintained by selectively injecting an oxygen-containing gas so that a reducing atmosphere is always formed on the surface of the melt. Therefore, the reaction is controlled in such a way that complete combustion of hydrocarbons with the formation of CO ₂ and H ₂ O does not occur, and CO and H ₂ content are also formed in the process gas.

When the loaded mixture melts, a metal phase is formed containing blister copper, as well as heavy metals, in particular lead (Pb), tin (Sn), zinc (Zn), nickel (Ni), as well as noble metals - gold (Au) and silver (Ag). Mineral components of the electronic scrap of the loaded mixture together with oxides of elements with an affinity for oxygen, in particular such as lead (Pb), tin (Sn), nickel (Ni), iron (Fe), silicon (Si), titanium (Ti) , sodium (Na), calcium (Ca), aluminum (AI), magnesium (Mg), etc., form a lighter slag phase.

Due to the completeness of combustion on the surface of the melt, the heat supply to the surface of the melt and the degree of oxidation of associated elements are simultaneously controlled. In this way, selective oxidation of undesirable components, such as elemental aluminum or silicon, is carried out and they are purposefully transferred to the slag phase. Therefore, the resulting metal phase is characterized by a residual content of the two indicated elements, which is less than 0.1 weight for each element. %.

If in step i) too much oxygen has been added to the process, the first slag phase can advantageously be reduced with a reducing agent. In this way, the first slag phase is purified and further reduced, so that if necessary, existing heavy metal oxides, such as, for example, SnO, CU ₂ O, NiO, PbO and/or ZnO, can be converted into their metallic form and thus , into the metallic phase.

The melting reactor is preferably a metallurgical vessel, such as, for example, a tipping rotary converter, in particular a so-called Top Blowing Rotary Converter (TBRC), or a tipping vertical converter. In an advantageous embodiment, the metallurgical vessel comprises a first tap hole for discharging a metal phase and/or a second tap hole for discharging a slag phase. In this case, the tap hole for releasing the metal phase is advantageously located in the bottom and/or side wall of the corresponding melting reactor, so that the metal phase can be extracted through it.

In an advantageous embodiment, the loaded mixture, in particular each of the loaded mixtures, contains electronic scrap in an amount of at least 10.0 wt. %, more preferably in an amount of at least 15.0 wt. %, even more preferably in an amount of at least 20.0 wt. %, further preferably in an amount of at least 25.0 wt. %, further preferably in an amount of at least 30.0 wt. %, further preferably in an amount of at least 35.0 wt. %, further preferably in an amount of at least 40.0 wt. %, further preferably in an amount of at least 45.0 wt. %, further preferably in an amount of at least 50.0 wt. %, further preferably in an amount of at least 55.0 wt. %, further preferably in an amount of at least 60.0 wt. %, further preferably in an amount of at least 65.0 wt. %, further preferably in an amount of at least 70.0 wt. %, further preferably in an amount of at least 80.0 wt. %, further preferably in an amount of at least 90.0 wt. %, and most preferably in an amount of at least 95.0 wt. % in relation to the entire charge.

In yet another advantageous embodiment, the feed mixture contains a slag-forming additive, and/or a slag-forming additive is added to the process in steps i) and/or iii). In this regard, it is particularly preferably provided that the charge mixture contains a slag-forming additive in an amount of at least 1/8 of the mass fraction of electronic scrap present in the charge mixture, more preferably in an amount of at least 1/5, even more preferably in an amount of at least 1/3. The slag-forming additive is advantageously selected from the range of iron, calcium oxides, iron oxides, silicon oxides, magnesium oxides, sodium oxides, calcium carbonates, magnesium carbonates, sodium carbonates and/or calcium hydroxides, iron hydroxides, magnesium hydroxides, sodium hydroxides, and /or mixtures thereof.

Advantageously, the electronic scrap or the charged mixture has an (elemental) aluminum content of at least 0.1 wt. %, more preferably an aluminum content of at least 0.5 wt. %, even more preferably the aluminum content is at least 1.0 wt. % and most preferably an aluminum content of at least 3.0 wt. %. With regard to the maximum content of elemental aluminum, the electronic scrap or the charged mixture is limited, since too high an aluminum content negatively affects both the viscosity and thus the fluidity of the slag phase, as well as the separation properties between the metal phase and the slag phase. Therefore, the electronic scrap or the loaded mixture preferably contains at most 20.0 wt. % aluminum, more preferably at most 15.0 wt. % aluminum, even more preferably at most 11.0 wt. % aluminum and most preferably at most 8.0 wt. % aluminum.

If the aluminum content in the electronic scrap or the loaded mixture is less than 5.0 wt. %, it is advantageously provided that a slag-forming additive is added to the process, preferably in step i), in an amount of up to 25.0 wt. % relative to the amount of electronic scrap contained in the loaded mixture. If the aluminum content in the electronic scrap or, accordingly, in the loaded mixture is greater than the value indicated above, in particular, it is 5.0 - 10.0 wt. %, then the amount of slag-forming additive added to the process, preferably in step i), advantageously amounts to 10.0 - 45.0 wt. %. If the aluminum content in the electronic scrap or the charged mixture is even greater, in particular more than 10.0 wt. %, then the amount of slag-forming additive added to the process, preferably in step i), advantageously amounts to 20.0 - 60.0 wt. %.

Advantageously, the charged mixture is configured such that its viscosity in the molten, i.e. liquid aggregate state, lies in the range from 0.01 to 10.0 Pa*s, more preferably in the range from 0.05 to 10.0 Pa* s, even more preferably in the range from 0.1 to 10.0 Pa*s and most preferably in the range from 0.1 to 5.0 Pa*s.

The loading and thus the energy input into the melting reactor can be uneven due to different grain sizes and, in particular, due to grain sizes that are too large, so that undesirable conditions arise during the melting process. The electronic scrap is therefore provided in shredded form, whereby the shredding process always includes smaller unavoidable fractions, such as, for example, dust and/or powdery fractions.

Advantageously, the electronic scrap is shredded to a grain size of less than 20.0 inches, more preferably to a grain size of less than 15.0 inches, even more preferably to a grain size of less than 12.0 inches. .48 cm), further preferably to a grain size of less than 10.0 inches (25.4 cm), further preferably to a grain size of less than 5.0 inches (12.7 cm), and especially preferably to a grain size of less than 2.0 inches ( 5.08 cm). However, the grain size should not be less than 0.1 inches (0.254 cm), preferably should not be less than 0.5 inches (1.27 cm), even more preferably should not be less than 1.5 inches (3.81 cm). In this regard, it has proven to be particularly advantageous if, in addition, the electronic scrap according to step i) is provided in the form of extruded products. Thanks to this, firstly, the working space of the melting reactor is optimally used, and, secondly, the melting process is accelerated.

In the context of the present invention, the term "compressed article" means a piece compressed and formed from shredded electronic scrap. In this regard, the compressed products may take the form of briquettes, lumps and/or agglomerated bags.

Below, the invention and specifications are explained in more detail by way of example. It should be noted that the invention is not limited to the illustrated embodiment. In particular, unless expressly stated otherwise, only certain aspects of the stated circumstances may also be selected and combined with other components and information obtained from the present description.

Example:

The method is, in principle, intended for the extraction of non-ferrous metals of groups 8-14 of the periodic table of elements. In this embodiment, the method is particularly designed to recover blister copper from electronic scrap, with significant proportions of silver (Ag), gold (Au), platinum (Pt) and palladium (Pd) also being recovered.

In the first stage of the process, there was first a feed mixture containing 68 wt. % electronic scrap, the rest of which was a slag-forming additive in the form of 25 wt. % iron oxide additive and 7 wt. % SiO ₂ additive.

The prepared electronic scrap consisted of 1.5 to 2.5 inch (3.81 to 6.35 ms) compacted products compressed from shredded electronic scrap. The electronic scrap contained 18 wt.% Cu, 25 wt. % hydrocarbons, 7 wt. % Al, 12 wt. % Si, 7 wt. % of heavy metals from a series including Pb, Sn, Ni, Cr, as well as Zn, 3 wt. % Ca, 2 wt. % halogens and 5 wt. % Fe, the rest was chemically bound oxygen, as well as inevitable impurities.

The feed mixture was melted in the presence of atmospheric oxygen in a rotating melting reactor, in this case a rotating top-blast converter. To do this, the mixture was ignited in the melting reactor using a burner and the pyrolytic reaction was started. The calorific value of the loaded mixture was approximately 9800 kJ/kg.

The combustion reaction and thus the heat generation was purposefully controlled by the added amount of oxygen. The volumetric flow rate of atmospheric oxygen was coordinated in such a way that there was always a reducing atmosphere on the surface of the melt, complete combustion of the organic fraction with the formation of CO ₂ and H ₂ O did not occur, and the process gas had a specific content of CO and H ₂ . It was burned at the top of the melting reactor or outside the melting reactor.

After a few minutes at a temperature of approximately 1200-1300°C, a melt was formed with a first metal phase and a first slag phase floating on the metal phase. The first slag phase was then separated according to the second process step through a tap hole located in the side wall of the melting reactor. The slag phase was analyzed and showed a copper content of 0.3-2.0 wt. %, and a viscosity of approximately 0.3 Pa*s.

The first metal phase remaining in the correct reactor, which had a copper content of approximately 97 wt. %, in the next stage of the process was refined or, accordingly, converted using oxygen-containing gas. For this purpose, oxygen-enriched air was blown into the metal first phase using a lance, so that the elements present in the metal phase with an affinity for oxygen, such as lead (Pb), tin (Sn), nickel (Ni), iron, were oxidized (Fe), silicon (Si), titanium (Ti), sodium (Na), calcium (Ca), aluminum (A!), magnesium (Mg), etc. This stage of the process, if necessary, can be supported by adding slag-forming additives and thermostatically controlled by adding copper-containing waste used as cooling scrap. Said second slag phase formed also had a lower density compared to the metal phase. In this case, the process step involving conversion was repeated twice, and after each conversion step, the resulting slag phase was removed from the surface and analyzed for composition. At the last stage of conversion, a copper-enriched slag phase was formed containing approximately 20 wt. %. copper in the form of copper oxide (CU ₂ O).

Through another tap hole located in the bottom of the smelter reactor, the refined/converted first metal phase was released from the smelter reactor, while the copper-rich slag phase of the first conversion stage remained in the smelter reactor.

The process then started with a new charge according to step i) by introducing a new charge mixture containing electrical scrap into the copper-rich slag phase and melting it. In this case, the second loaded mixture had the same composition as the first loaded mixture, but this is not mandatory. Thanks to the reducing conditions existing during melting, it was possible to directly extract blister copper and heavy metals contained in the slag phase. Since re-melting of the slag phase can be avoided in this way, approximately 350 kW of energy can be saved per ton of slag remaining in the smelting reactor.

Claims (19)

1. A method for extracting metals of groups 8-14 from a mixture containing electronic scrap loaded into a melting reactor, including the following steps: i) providing and melting a feed mixture containing electronic scrap in a melting reactor to produce a first melt containing a first metal phase and a first slag phase; ii) separating the first slag phase from the melting reactor; iii) refining the remaining first metal phase by means of an oxygen-containing gas to obtain a second copper-rich slag phase; iv) separating the refined first metal phase from the smelting reactor and v) adding the next feed mixture containing the electronic scrap to the remaining second copper-enriched slag phase and repeating steps i) to v) of the process. 2. The method according to claim 1, wherein in step iii) the copper-containing waste is added to the remaining first metal phase. 3. The method according to claim 1 or 2, in which after step iii) the second slag phase is isolated and step iii) is repeated. 4. Method according to any one of paragraphs. 1-3, in which the first slag phase is reduced by means of a reducing agent. 5. Method according to any one of paragraphs. 1-4, in which the entire process is carried out at a temperature of at least 1150°C. 6. Method according to any one of paragraphs. 1-5, in which the loaded mixture contains electronic scrap in an amount of at least 10 wt.%. 7. Method according to any one of paragraphs. 1-6, wherein the charge mixture contains a slag-forming additive, and/or a slag-forming additive is added to the process in steps i) and/or iii). 8. The method according to claim 7, in which the loaded mixture contains a slag-forming additive in an amount of at least 1/8 of the mass fraction of electronic scrap contained in the loaded mixture. 9. The method according to claim 7 or 8, in which the slag-forming additive is selected from the range including iron, oxides, carbonates and/or hydroxides of calcium, magnesium, sodium, silicon, iron. 10. Method according to any one of paragraphs. 1-9, in which the electronic scrap has an aluminum content of from 0.1 to 20.0 wt.%. 11. Method according to any one of paragraphs. 1-10, in which the electronic scrap has an organic content of from 5.0 to 80.0 wt.%. 12. Method according to any one of paragraphs. 1-11, in which the electronic scrap is crushed to a grain size of less than 50.8 cm and, if necessary, provided in step i) in the form of compressed products. 13. Method according to any one of paragraphs. 1-12, in which step i) is maintained by injecting an oxygen-containing gas to form a reducing atmosphere on the surface of the melt. 14. Method according to any one of paragraphs. 1-13, in which the metal phase is removed through a tap hole located in the bottom and/or side wall of the melting reactor.