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INVENTION
Russian Federation Patent RU2109076

METHOD FOR PROCESSING WASTE containing copper, zinc, silver and gold

Name of the inventor: Veryovkin Georgy; Valery V. Denisov; Buzlaev Yuri Mikhailovich
The name of the patentee: Veryovkin Georgy; Valery V. Denisov; Buzlaev Yuri Mikhailovich
Address for correspondence:
Starting date of the patent: 1996.02.14

Usage: As for waste, mainly metallurgical production with the recovery in commodity output of copper and zinc, silver and gold in the form of a high-standard concentrates.

The inventive method is based on processing of the starting material salt aqueous solution containing an oxidizing agent to intensify leaching of valuable components, particularly silver, and gold, followed by absorption of gold and silver, selective extraction and concentration of copper and zinc electroplating. The method was tested on a waste of metallurgical production, containing, by weight. % Copper 2.5 - 3.5; zinc, 0.7 - 1.5; silver, 0.01 - 0.02; Gold 0.0002 - 0.0004; iron 30 - 35. The combination of intensive leaching and selective sorption extraction and recovery of metals makes it possible to nearly double the output of marketable products in the processing of metallurgical waste.

DESCRIPTION OF THE INVENTION

The invention relates to non-ferrous metals hydrometallurgy, preferably to methods for recycling metallurgical industries, and can be used for recycling electronic, and electrical engineering industries.

A method of processing copper-bearing material with a low copper content comprising leaching copper electroextraction followed by [1] (1 analog).

According to this method, leaching of copper-containing products are subjected to solutions of sulfuric acid. Thus the copper goes into solution. Copper-containing solution after the filtration and purification for electroextraction fed to the recovery of copper metal into the cathode.

The advantages of the method include the simplicity and processability, low cost copper.

The disadvantages of this method are:

- Low rate of copper leaching due to the fact that only dissolved in the leaching of oxidized metal copper and the oxidation rate (and metallic sulfide) under these conditions is low enough;

- The accumulation of iron in the leach solution and the absence of effective methods of its output from the process;

- Inability to extract the precious metals;

- The poor quality of the resulting copper, which requires further processing to bring it to the required of conditions;

- The impossibility of passing the extraction of other non-ferrous metals;

- Availability of additional operations to bring the ballast salts.

The method for extracting gold and silver from the materials with low contents of metals including silver and gold dissolution with alkaline solutions of sodium cyanide followed by sorption on activated carbons of [2] (analog 2).

According to this method, materials containing gold and silver are treated in vats or specially prepared on the basis of waterproofing stacks) alkaline solutions of cyanide salts (sodium cyanide or calcium cyanide). Thus under the influence of atmospheric oxygen and gold and silver are oxidized bind cyanide ions in cyanide complexes. Extraction of gold and silver from the leach solution is carried out by their sorption on active charcoal.

In the embodiment of "heap leaching" of the prepared stack method is suitable for the extraction of gold and silver in their original content, respectively, 1.0 and 10 g / t, with a lower content of gold way to becoming insolvent, as non-ferrous metals, usually associated silver and gold, in this method are not extracted.

By way of advantages are its simplicity, technology and economy.

Disadvantages of the method include high toxicity of sodium cyanide which limits the field of application of the method and complexity of associated ferrous metal extraction, which would substantially improve the economic performance.

A simple combination of methods [1] and [2] in order to improve economic performance through integrated sequential extraction of non-ferrous and precious metals is not possible because of the risk allocation in the gas phase hydrogen cyanide when changing environment with an alkaline to acidic, or vice versa.

The closest to the claimed technical essence and attainable effect is a method for processing of metallurgical waste. The starting material is subjected to oxidative leaching, the pulp feeding directly the gaseous chlorine leach. This is achieved quite high recovery of non-ferrous and precious metals at the same time: 80-90% for precious metals and 80% for copper and zinc. As a result, the method is suitable for materials with very low contents of non-ferrous and precious metals: copper and 1-2% zinc, up to 1.5 g / t gold.

The disadvantages of the method include:

1. unsuitable for use in the embodiment of "heap leaching" due to uncontrolled release into the atmosphere of chlorine gas, but also in mind the impossibility of ensuring uniform supply of chlorine through the material of the stack, since the movement of gas through the particulate material is mainly through the channels.

2. The process is carried out in the acidic range, wherein the solubility of chlorine is low (<0.5%), its high volatility, and that is why even in the version of "vat leaching" chlorine oxidation potential is not fully used.

3. The leaching in the acidic region is not highly selective, as evidenced, for example, using the prototype flowsheet purification operations from iron lime treatment solutions. As a result, it eliminated the possibility of direct extraction of copper concentration and purification for subsequent electroextraction it as a high-quality metal cathode, as is done in most modern hydrometallurgical circuits. For this reason, the copper in the prototype method is recovered as low value precursor - cement copper (cementation on iron scrap) along with gold and silver, followed by processing of the intermediate product in the metals.

The technical result achieved by the invention is to improve the technical and economic performance of the process at the waste of metallurgical production, containing copper, zinc, gold and silver.

Technical result is achieved by the simultaneous extraction of these metals into solution in the leaching stage, for which is used as a solvent metal having complexing properties ammonium salt alkaline solutions containing an oxidizing agent. As the oxidizing agent used active chlorine leach pulp is dosed in to maintain a predetermined potential. Subsequent extraction concentration and separation of non-ferrous metals allows you to extract all of the valuable components of the solution in the form of commodities.

The essence of the method consists in targeting complex formation and oxidation processes to increase the extent of dissolution of non-ferrous metals and accelerate the process translated into a solution of the sulfide and metallic forms by reactions

METHOD FOR PROCESSING WASTE containing copper, zinc, silver and gold. Russian Federation Patent RU2109076 METHOD FOR PROCESSING WASTE containing copper, zinc, silver and gold. Russian Federation Patent RU2109076

The above equations show that the presence of ammonia in the leach solution and ammonium salts necessary for binding ferrous and precious metals in the complex compounds. Additionally, free ammonia is required for the binding of sulfuric acid produced in the oxidation of sulfide compounds (equations 4,5,8 and 11).

The difference between the proposed method from the nearest analogue is to combine the oxidation and complex that provides a quick and full translation in all components of the solution. Subsequent operations of isolation and separation of valuable components from the leach solution using sorption and extraction operations, allowing to obtain a high-quality commercial products, and the proposed method is distinguished by the method of analog.

Sorption of gold and silver, in addition to the primary purpose - the concentration of precious metals, and provides lightening deep solutions entering the redistribution extraction and lowering the redox potential of the solutions to a level that does not cause the destruction of the extractant. Therefore, the concentration of gold and silver, and is preceded by extraction of non-ferrous metals division. Desorption of gold and silver from saturated sorbent phase are strong solutions of sodium cyanide to give a gold-silver productive electrolyte. This allows for additional cleaning of precious metals from the impurities and bring the precious metals in a compact gold-silver concentrate.

After sorption of gold and silver on carbon sorbent has an increased mechanical strength of the clarified solution to selectively extract copper extractant class of beta-diketones in the regime-controlled extractant deficit, then from copper depleted raffinate recovered zinc extractant oksioksimov class. Recovery of copper and zinc from extracts of similar to the corresponding electrolyte producing sulfuric acid solutions is carried out, which is used as the respective spent electrolyte electrolysis copper and zinc.

As a result, the proposed method allows to extract metals from waste containing copper, zinc, silver and gold, all the valuable components with a degree of extraction of over 90% in the form of commodities of high consumer quality.

example 1
A weighed sample of material comprising,%: Fe 28,5; Cu 3,6; Zn 1,1; Au 1,9 g / t; Ag 73 was subjected to leaching with a solution containing in g / l: NH 4 Cl 100, NH 3 45. Active chlorine in the form of sodium hypochlorite solution is dosed into the pulp in order to maintain a predetermined potential of the solution within 700-1100 mV. For comparison, a similar sample had a flow diagram for the prototype method.

Leaching results are presented in Table 1 .

As can be seen from the data in Table 1. The data in comparison with the prior art proposed method allows:

- By prolonged extraction to increase leaching of copper and zinc in solution more than 10% gold - by almost 20%, silver - almost twice;

- Significantly reduce leaching time: extracting all technologically acceptable metal (above 80%) is achieved in 5 hours in the proposed method, whereas in the prior art five hours silver and copper recovery less than 50%.

example 2
Leaching the pulp obtained in the manner described in the previous example, a carbon sorbent in contact for 24 hours at a weight ratio of "pulp: sorbent" equal to 50,000: 1.

After 24 hours, the carbon sorbent is separated from the slurry, washed with water and dried to constant weight. The pulp was filtered for analysis of solid and liquid phases on contents of silver and gold.

Results Sorption of gold and silver from the leach slurry are listed in Table 2 .

As can be seen from the data in Table 2 data, the recovery of gold from the liquid portion of the slurry, even at such a high ratio of "pulp: sorbent" was 95% (91.2% overall recovery). Silver extraction phase sorbent in the experimental conditions (the liquid portion of the pulp) was more low - 59.4% due to the lower values of the distribution coefficients of silver in the adsorption system. Total silver in the sorbent phase extraction was found to be 58.2% of its original amount. The gold content in the saturated sorbent phase was 1.2%, 29.5% silver.

Thus, the above examples show that even under extremely unfavorable phase ratios can be obtained relatively high technological characteristics of precious metals extraction.

Example 3. Sorbate obtained after adsorption of gold and silver, comprising in g / l: Cu 11,94; Zn 3,66; Ag (29 mg / l); Au (0,03 mg / l), in contact with about 20% of beta-diketone in kerosene within 10 seconds at a volume ratio of the phases V:. V = 1,5. After contacting the phases separated by centrifugation. The phases were determined metal content.

Metal extraction results are shown in Table 3 .

Thus, given in Table 3 data shows that the recovery of copper from the sorbate in the experiment was 95%. In addition, copper extraction of beta-diketone solution provides a good selection from copper zinc and silver: copper degree of purification of these metals were respectively> 1700 and> 2900 for one stage.

Example 4 The extract obtained in the preceding example, contacted with a solution simulating the electrolyte circulating electroextraction copper having a composition, g / l: Cu 30; H 2 SO 4155 for 10 seconds at a volume ratio of the aqueous and organic phases = 1. After contacting the phases separated by centrifugation. The resulting reextract contained, g / l: Cu 47; H 2 SO 4 130. The electrolyte composition suitable for such electroextraction copper.

example 5
The raffinate obtained in Example 3 was contacted with 20 vol.% Solution oksioksimov reagent grade kerosene for 30 seconds with a ratio of the aqueous and organic phases 0.67. The phases were separated by centrifugation after contact, then phase conjugated in the metal content was determined. Metal extraction results are shown in Table 4 .

As can be seen from the data in Table 4 the data extraction from a solution of 95% zinc. Selection of copper in this case is worse, since in alkaline media class oksioksimov extractants are effective with respect to both copper and zinc in relation to. This means that to obtain a clean, not containing copper zinc electrolyte after copper extraction raffinate must be purified, for example, using a widely used in zinc plant electrolyte for copper cementation on zinc powder. This, in addition to cleaning copper raffinate from enables withdraw a concentrate remaining in the raffinate gold and silver.

example 6
This example demonstrates the possibility of using recycling of the raffinate after removal of nonferrous metals in the leaching cycle, thereby achieving isolation process reactants by recycling the raffinate electrolytic treatment.

A sample containing Cu 3,5%; Zn 1,2%; 2 Au g / t; Ag 70 g / t treated in static solution composition, g / l: 80 of ammonium sulfate; 25 free ammonia (pH 9.9); Ammonium chloride 15; active chlorine (ORP ORP) 1100 mV.

Composition solution was obtained, g / l: 80 of ammonium sulfate; 17 free ammonia (pH 9.5); Ammonium chloride 15; Cu 11,6; Zn 3,7; Au 0,04 mg / l; Ag 9,5 mg / l of active chlorine (ORP) 220 mV.

Recovery of valuable components in the solution was,%: Cu 99,3; Zn 98,7; Au 94; Ag 89. From the resulting solution had a sorption Au and Ag AMH activated charcoal. Extraction phase sorbent composition,%: gold 99.8; Silver 96.7; Wherein the ORP dropped to 120 mV.

Sorbate obtained from spent zinc and copper extraction. The recovery of copper and zinc in the organic extracts was,%: Cu 99,8; Zn 96,6. Obtained raffinate composition, g / l: Ammonium sulfate 80; free ammonia 12.5 (pH 9.0); Ammonium chloride 15; Cu 0,02 g / l; Zn 0,04 g / l active chlorine (ORP) 70 mV.

This raffinate is subjected to electrolysis at a current density of 1400 A / dm 2 for 15 minutes. Composition solution was obtained, g / l: 80 of ammonium sulfate; 9,5 free ammonia (pH 8.5); Ammonium chloride 15; Cu <0,001 g / l; Zn 0,01 g / l; chlorine (ORP) of 1,200 mV after ammonia doukrepleniya composition meets the original leach solution and can thus be used to treat a new batch of material.

example 7
The extract obtained in Example 5 was contacted with a solution simulating the electrolyte circulating electroextraction of zinc having the composition in g / l: Zn 120; H 2 SO April 21 for 1 min at a volume ratio of the aqueous and organic phases 0.2. After contacting the phases separated by centrifugation. The resulting reextract contained, g / l: Zn 131,6; 5 Cu; pH 4. The electrolyte of the composition can be directed to zinc electroextraction.

Thus, the method by increasing the complexity of the use of raw materials allows the processing of man-made materials containing copper, zinc, silver and gold, to achieve a high degree of extraction of valuable components.

With respect to that described in the above examples, the inventive method allows the material after prolonged (10 hours) leaching to extract additional production by nearly $ 5 in processing each ton of raw material, that is, almost 15% increase in output of marketable products of higher quality.

Moreover, the proposed method reduces the process time by almost half, almost double the performance. This ceteris paribus allows to increase output per unit of time with the same production space by almost 50% compared to the prototype method.

CLAIM

  1. Method for processing waste containing copper, zinc, silver and gold, comprising leaching copper, zinc, silver and gold in the presence of a chlorine-containing oxidant, followed by removing the metal from the resulting solution, characterized in that the leaching of copper, zinc, silver and gold in the presence of a chlorine-containing oxidant carried alkaline ammoniacal brine, extraction of metals from the resulting solution are performed sequentially: first, silver and gold sorption on the carbonaceous sorbent and then copper extraction solution of beta-diketone in an organic solvent and then from the resulting raffinate - zinc extraction with an organic solution oksioksima in an organic solvent with the separation of the raffinate, purified from non-ferrous and precious metals.

  2. A method according to claim 1, characterized in that the chlorinated oxidant injected into the leach slurry to maintain the desired redox potential determined by the composition of the starting material.

  3. A method according to claim 1 or 2, characterized in that the chlorine-containing oxidant as used active chlorine.

  4. A method according to any one of claims 1 - 3, characterized in that the raffinate obtained after extraction of copper, before removing the zinc from it is purified of traces of copper, silver and gold by cementation.

  5. A method according to any one of claims 1 - 4, characterized in that the active chlorine leach raffinate produced during electrolysis, purified from non-ferrous and precious metals.

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Publication date 05.12.2006gg