RU2444573C2 - Manufacturing method of concentrate of precious metals from sulphide copper-nickel raw material - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method involves separation of Bessemer matte into metallised and sulphide fractions and oxidation leaching of metallised fraction with solution at the controlled chlorine supply. At that, ratio of sulphur and copper contained in metallised fraction is 0.3-0.7. Leaching is performed in the value range of oxidation-reduction potential of 430-470 mV, preferably 440-450 mV. Sludge of baths of electrolytic nickel refining of processing technology of sulphide Bessemer matte fraction is supplied together with metal faction of Bessemer matte for leaching.

EFFECT: reduction of flow of reagents and scope of equipment, simplification of instrumentation of the process, reduction of losses of precious and non-ferrous metals and improvement of incomplete production.

7 cl, 2 dwg, 3 tbl, 5 ex

Description

The invention relates to the field of non-ferrous metallurgy, in particular to the production of precious metal concentrates from sulfide copper-nickel raw materials.

A known method for the production of electrolyte nickel from copper-Nickel matte [Yu.V. Baimakov A.I. Zhurin. Electrolysis in hydrometallurgy. - M .: Metallurgy, 1977, p.201], including flotation separation of slowly chilled and ground Feinstein into copper and nickel concentrates, oxidative roasting of nickel concentrate, cinder recovery, smelting on anodes and electrolytic refining. The disadvantage of this method is the involvement of the entire amount contained in Feinstein precious metals in successive stages of firing, smelting and electrolytic refining, resulting in significant losses and a large volume of work in progress.

A known method of processing copper-Nickel Feinstein, including the allocation of a metallized fraction with its subsequent carbonylation (RF Patent No. 2158775). The disadvantage of this method is the impossibility of a significant concentration of precious metals in the carbonylation residue and the related need for its further hydrometallurgical processing with the consumption of sulfuric acid and the oxidation of sulfides to sulfates with a corresponding consumption of a neutralizer and an increase in sulfate runoff. In general, the implementation of this method leads to the need for the involvement of equipment and personnel of various workshops and requires increased capital costs.

There is a method of processing industrial products of copper-nickel production, in particular metallized Feinstein fraction by oxidative sulfuric acid leaching in two stages (RF Patent No. 2144091). The disadvantage of this method is the consumption of sulfuric acid to dissolve the metals contained in the metallized fraction with the corresponding subsequent consumption of a catalyst and an increase in sulfate runoff. In addition, the method is applicable only to materials with a low sulfur content, since it does not provide the opening of copper sulfides and the transfer of copper from sulfides into solution. Limiting the sulfur content in the metallized fraction does not allow for a high extraction of precious metals into the metallized fraction. The total leaching time in periodic mode is 13 hours, which determines the need for a large amount of equipment.

The closest we adopted for the prototype is a method for processing intermediate products of copper-nickel production containing precious metals, implemented in a two-stage process of sulfuric acid oxidative dissolution (RF Patent No. 2160785). Processed industrial products are characterized by a significant degree of metallization. In the first stage, the metallized material is leached in a solution of sulfuric acid at atmospheric pressure during aeration, and the second stage of dissolution is carried out in an autoclave. The specified method, providing acceleration of the process and a significant concentration of precious metals in the leach residue, requires the use of expensive equipment, is characterized by a high consumption of sulfuric acid and determines the conversion of sulfide sulfur to sulfate with a subsequent corresponding consumption of a neutralizer and an increase in sulfate production flow. In addition, despite the fact that the autoclave process can accelerate dissolution, the solubility limitations of nickel and copper sulfates require both leaching stages to be carried out at relatively low pulp densities, which necessitates the use of increased volumes of equipment (especially at the atmospheric stage) compared to work in chloride environments.

The objective of the present invention is to reduce losses and reduce the incomplete production of precious metal concentrate, reduce reagent costs, reduce the amount of equipment and simplify the hardware design of the process, produce elemental sulfur necessary for the process of efficiently cleaning the leaching solution from copper due to separation and leaching with controlled chlorine supply metallized fraction of copper-nickel Feinstein with a ratio of sulfur and copper content of 0.3-0.7.

The technical result is achieved by the fact that upon receipt of a precious metal concentrate by separating Feinstein into metallized and sulfide fractions and oxidative leaching of the metallized fraction with a solution with controlled supply of chlorine according to the invention, the ratio of sulfur and copper contents in the metallized fraction is 0.3-0.7.

Together with the metallized fraction, the leach is fed to the nickel electrolytic refining bath sludge or the reduced calcination cinder of the nickel concentrate extracted from the sulfide fraction of the nickel concentrate and leached in the range of oxidation-reduction potential (ORP) of 430-470 mV, preferably 440-450 mV. The leach residue is separated into a precious metal concentrate and elemental sulfur, and the leach solution is purified from copper by the addition of nickel powder and elemental sulfur, the elemental sulfur being extracted from the leach residue of the Feinstein metal fraction, and the nickel powder is produced by reducing the calcination calcine of the nickel concentrate nickel concentrate nickel concentrate .

At the leaching stage, for a given redox potential of the pulp, controlled by the feed rate of chlorine and / or the metallized fraction, nickel, cobalt, copper, iron and silver are extracted into the solution, and the sulfide sulfur present in the metallized fraction is oxidized to elemental sulfur. Precious metals (with the exception of silver) are concentrated in the leach residue, which is further released by known methods from elemental sulfur to obtain a concentrate of precious metals. The resulting precious metal concentrate can be brought to commodity concentrates in various ways. The choice of a specific technology for its processing is determined by the specifics of a particular production. To obtain commodity concentrates, a new technology can be developed or the available processing capacities of sludge from existing plants can be used.

Copper is removed from the leach solution of the metallized Feinstein fraction using nickel powder — a reduced calcine roasting of nickel concentrate extracted from the Feinstein sulfide fraction and elemental sulfur isolated from the leach residue of the metallized fraction. The deposition of copper from concentrated chloride solutions by cementation on nickel powder without the use of elemental sulfur does not allow for the deep purification of copper. At the stage of copper deposition with nickel powder and elemental sulfur, deep extraction of nickel and cobalt from nickel powder into the solution is achieved with the reduction of elemental sulfur and copper deposition from the solution into sulfides. At the same time as copper, silver precipitates in cake, which has passed into the solution at the stage of leaching of the metallized fraction. The resulting copper cake is transferred to copper production to obtain marketable copper and silver concentrate. The solution purified from copper is further purified from iron and cobalt by known methods and transferred to the electroextraction of nickel. Chlorine released during nickel electroextraction is directed to leaching of the Feinstein metal fraction.

The total redox reactions occurring during leaching are generally described by the following equations:

The oxidation mechanism is implemented with the participation of a mediator - a pair of Cu (I) / Cu (II).

The total redox reactions occurring during the deposition of copper are summarized by the following equations:

The redox potential of the pulp, defined by the ratio of the chlorine feed rates and the Feinstein metallized fraction, is chosen so as to ensure the most complete reaction (1) - (6).

In one embodiment of the method for producing a single precious metal concentrate, the sludge from the electrolytic nickel baths of the main production is also fed to the leaching stage. Leaching of sludge together with the metallized Feinstein fraction eliminates the need for a separate enrichment process. In another embodiment, simultaneously with the metallized Feinstein fraction, a reduced calcine roasting of nickel concentrate isolated from the Feinstein sulfide fraction also enters the chlorine leach. Moreover, all precious metals are concentrated in the total leach residue, and the entire volume of nickel is produced by electroextraction from a single leach solution purified from impurities.

The leach pulp is filtered off, the leach residue is sent to smelting sulfur, and the filtrate is deposited on copper. The reagents involved in the copper cleaning process are sulfur extracted from the leaching residue and ground metal and a metal precipitant — a reduced calcine cinder of nickel concentrate extracted from the sulfide fraction of Feinstein. Cu ^{2+ ions are} reduced to Cu ⁺ by reaction (8) and then converted to sulfide by reactions (9) and (10). Silver is deposited in the cake (reaction (11) and, in part, trace amounts of gold and platinum group metals that have passed into the solution, which makes the copper treatment unit a barrier to their losses in the process of cleaning the solution and electroextraction. Transferring the copper cake to copper production reduces the quality requirements for separation sulfur and precious metal concentrate, since the precious metals contained in the melted sulfur will be separated into the corresponding intermediate products (sludge or the residue of sulfuric acid leaching of a copper cinder) in a copper roduction.

Deep sulfur recovery from the leach residue is achieved by leaching the residue obtained after filtration of molten sulfur in an alkali solution. The alkaline polysulfide solution is sent to the redistribution of copper purification.

The use of elemental sulfur in the process of copper cleaning determines the organization of the process of isolating the metallized fraction of Feinstein. The ratio of sulfur and copper contents in it should be such that the amount of sulfur smelted from the leach residue is sufficient to bind the copper transferred to the solution into sulfides of the general formula Cu _n S, where 1 <n <2. The estimated ratio is 0.25-0.5, but taking into account the incomplete operation of sulfur in the process of copper cleaning, the desired range is 0.3-0.7. When the copper content in the metallized fraction of 20%, the rational sulfur content is 6-14%. A relatively high level of sulfur determines the reduction in the cost of separating the Feinstein metallized fraction in comparison with the option to withdraw low-sulfur industrial product and determines the increase in the share of precious metals processed by a separate technology outside the main production, which reduces their total losses and work in progress. However, with a higher sulfur content in the metallized fraction, the full use of the melted elemental sulfur in the process of copper cleaning leads to the production of copper cake with a significant content of elemental sulfur, which complicates its further processing. Partial use of melted elemental sulfur in copper cleaning is irrational, since it determines the need for organizing a deep cleaning operation of the amount of sulfur not involved in the copper cleaning process for its implementation as a commercial product.

After washing, the copper cake is sent to the copper production, where it is processed to anodes for the process of electrolytic refining of copper, or according to the firing - leaching - electroextraction of copper scheme.

In the described embodiments of the method, the leaching of the metallized Feinstein fraction is associated in a single technological scheme with the processing of the sulfide fraction by the existing or one of the promising technologies. These technological solutions, demonstrating the feasibility of the proposed method without a fundamental reconstruction of production, are not mandatory or the only possible ones. Isolation and leaching of the metallized Feinstein fraction can also be combined with various options for the hydrometallurgical processing of the sulfide fraction.

The following examples describe embodiments of the invention.

In example 1, the separation of copper-Nickel matte in the laboratory.

In solutions leaching experiments with a controlled supply of chlorine (Example 2), an industrially separated metallized fraction from the Feinstein (MF) separation with a particle size of <0.2 mm was used.

In the experiments of copper purification (Example 4), a reduced calcination cinder of nickel concentrate extracted from copper-nickel matte was used — nickel powder of tube furnaces (PNTP) —fractions — 0.40-0.63 mm.

In example 5, leaching of ordinary sludge of electrolytic refining of nickel anodes of fraction <0.1 mm was performed. When interpreting the results of this example, it should be borne in mind that with a separate processing of the metallized fraction, the content of precious metals in the sludge will be 3-4 times lower, which will not affect in principle the level of their extraction into the solution when the sludge is leached.

The compositions used in the experiments of intermediates are summarized in table 1.

Table 1 The compositions of intermediates used in the experiments of chlorine leaching and copper purification,% Ni Cu With Fe S total Pt Pd Rh Ru Ir Au Ag MF 63,2 17.7 1.71 7.88 9.56 0.019 0,096 0.004 0.0013 0,0005 0.0015 0.014 PNTP 88.4 4.09 2.09 3.40 0.11 Sludge 26 23.7 0.4 0.9 16.7 0.38 2.1 0,07 0.02 0.008 0.05 0.34

Example 1

600 g of copper-nickel matte were crushed to flotation size (grade less than 45 μm ~ 85%). The metallized fraction from the crushed Feinstein was isolated, modeling gravity enrichment, classification. The output of sulfide and metallized fractions was 86.6% and 13.4%, respectively. With a sulfur content of 12.1%, the recovery of palladium in the metallized fraction was 82.79% (Table 2).

table 2 Isolation of a metallized fraction from Feinstein by classification Namenova
nie Exit, % Content% Recovery% Ni Cu With Fe S Pd (g / t) Ni Cu With Fe S Pd Shredded
file matte 46.33 25.81 1.14 3.4 22.8 148.9 Sulphide fraction 86.6 44.70 26.30 1.10 2.9 24.4 29.6 83.52 88.21 83.45 74.39 92.83 17.21 Metallisy
fraction 13,4 56.82 22.64 1.41 6.4 12.1 917.2 16,48 11.79 16.55 25.61 7.17 82.79

Example 2

1.0 kg of the metallized fraction of copper-nickel matte matte composition shown in table 1, pulp in 3.75 l of a chloride solution of the composition, g / DM ³ : Ni - 47.6; Cu - 29.1; Cl - 74.0; HCl - 1.0 at a temperature of 95 ° C. During the experiment, by controlling the supply of chlorine, the redox potential of the pulp (ORP) was kept at a predetermined level in the range from 420 mV to 500 mV relative to the silver chloride reference electrode. The duration of the experiment was 3 hours. The results of the analysis of the leach residues and calculated from the analysis of the residue and the solution of extracts into the solution are given in table.3.

An analysis of the leaching results shows that at low ORP values, high recovery in copper solution is not achieved, and at high ORP values, oxidation to sulfate and transfer of the leachable metallized fraction into the sulfide sulfur solution significantly increase. In addition, the transition to a solution of ruthenium and iridium is substantially increased. Therefore, the recommended area for the implementation of the chlorine leaching process is 430-470 mV, preferably 440-450 mV.

Table 3 Indicators of the leaching process of the metallized Feinstein fraction at various ORP values controlled by the supply of chlorine ORP, mV 420 430 440 450 470 500 Content in the leaching residue MF,% Ni 7.0 6.1 6.8 6.5 5.2 4.0 Cu 27.0 20.9 12.9 5,4 3,1 0.7 With 1,0 1,0 1,1 1.4 0.9 1,0 Fe 3,1 2,3 1,6 0.9 0.7 0.5 S total 62.3 70.1 78.0 86.4 90.6 94.6 S e 42.5 54,4 66.3 78.9 85.3 91.2 Ag 0.0047 0.0044 0.0060 0.0073 0.0075 0.0058 Extraction into solution during leaching of MF,% ORP, mV 420 430 440 450 470 500 Ni 98.3 98.7 98.7 98.9 99,2 99.5 Cu 76.7 84.1 91.2 96.7 98.3 99.7 With 91.2 91.8 92.0 91.5 94.7 95.1 Fe 94.0 96.1 97.5 98.8 99.1 99.5 S ^2- to SO ₄ ^2- 0.5 1,1 1,5 3.0 8.0 21.0 Pt 0.04 0,07 0.1 Pd 0.013 0.04 0,07 Rh 2,3 3,5 5.1 Ru 6.2 9.6 15.0 Ir 5.7 8.9 16.3 Au 0.8 0.8 1,2 Ag 95.0 95.9 95.0 94.6 95.0 96.8 Yield balance 15.3 13.5 12.1 10.7 9.7 8.0

Example 3

The residue of the leaching of the experiment according to example 2, obtained with an ORP of 450 mV, weighing 100 g, was pulp in water, sodium sulfide and diesel fuel were added to the pulp. The pulp was loaded into a smelter, where it was mixed and then settled at 130 ° C. The mass of smelted sulfur was 67 g, the mass of the melting tails was 33 g. The melting tails were crushed to a fraction of 0.071 mm and treated with a hot alkali solution. The output of the leach residue - precious metal concentrate amounted to 68% by weight of the smelting tails, which corresponds to the complete removal of elemental sulfur. Precious metals concentrate composition,%: Ni - 28.5, Cu - 24.0, Co - 6.0, Fe - 3.9, S - 33.1, Pt - 0.77, Pd - 4.0, Rh 0.17, Ru 0.05, Ir 0.02, Au 0.06, Ag 0.032.

Example 4

45 g of reduced calcination calcined from copper-nickel matte nickel concentrate - powder of nickel tube furnaces (PNTP) were mixed with 35 g of elemental sulfur smelted from the chlorine leach residue of example 2 and ground to a fraction of 0.071 mm, pulp in 1 l of filtrate leach pulp of example 2 (ORP 450 mV). The pulp was mixed at 80 ° C for 30 minutes. Pulp redox potential, initially 425 mV, decreased within 3 minutes to the level of -20 - -40 mV and remained in this range during the entire copper treatment experiment. The copper content in the filtrate was 5 mg / dm ³ , silver - 0.015 mg / dm ³ . The yield of copper cake is 140.5% of the total mass of loaded PNTP and sulfur. Extraction into the solution from PNTP was,%: Ni - 85.3; Co - 95.1, Fe - 94.8. The composition of the copper cake and the extraction rates of the precious metals from the leaching solution into the cake are shown in Table 4.

Table 4 The performance of the copper treatment of the leaching solution of the metallized fraction of Feinstein The composition of the copper cake,% Ni Cu Co Fe S total S e Ag 5.3 53,4 0.2 0.4 31,2 3.6 0.1 Extraction in copper cake from a solution of leaching MF,% Pt Pd Rh Ru Ir Au Ag 21 83 86 84 53 51 99.8

Example 5

In an example similar to example 2, nickel sludge was leached out of electrolytic refining of nickel anodes at a potential of 450 mV relative to a silver chloride reference electrode. The yield of the leach residue was 55%, the content in the residue,%: Ni - 10.4, Cu - 1.0, Co - 0.3, Fe - 1.1, S total - 28.9, S elemental 21.9. Extraction into solution,%: Ni - 76.0, Cu - 97.7, Co - 58.3, Fe - 30.6, Ag - 75.5, Pt - 0.10, Pd - 0.07, Rh - 2.8, Ru - 7.7, Ir - 6.3, Au - 0.7.

Claims (7)

1. A method of producing a precious metal concentrate from a copper-nickel matte, comprising separating the matte into metallized and sulfide fractions and oxidative leaching of the metallized fraction with a solution with a controlled supply of chlorine, characterized in that the ratio of sulfur and copper in the metallized fraction is 0.3-0 , 7. 2. The method according to claim 1, characterized in that the leaching solution with a controlled supply of chlorine is carried out in the range of values of the redox potential of 430-470 mV, preferably 440-450 mV. 3. The method according to claim 1, characterized in that the leach residue is separated into a precious metal concentrate and elemental sulfur. 4. The method according to claim 1, characterized in that the leach solution is cleaned of copper by adding Nickel powder and ground elemental sulfur. 5. The method according to claim 4, characterized in that the elemental sulfur is extracted from the leach residue of the Feinstein metal fraction. 6. The method according to claim 4, characterized in that the nickel powder for purification from copper is produced by restoring a calcine calcine of nickel concentrate extracted from the sulfide fraction of Feinstein. 7. The method according to claim 1, characterized in that, together with the Feinstein metal fraction, a slurry of electrolytic nickel refining baths is fed to the Feinstein sulfide fraction processing technology for leaching with a solution with a controlled supply of chlorine.

Images