CN115011810B - Leaching process for improving copper recovery rate in zinc roasting ore - Google Patents

Abstract

The invention discloses a leaching process for improving the copper recovery rate in zinc roasting ores, which improves the copper leaching rate through low-acid reinforced copper leaching, directly recovers copper through weak acid leaching copper iron precipitation-weak leaching solution, realizes high-efficiency copper recovery and iron precipitation into slag, and reduces slag quantity and open-circuit impurities through neutralization and impurity removal, thereby solving the problems of large intermediate leaching slag quantity, iron balance, impurity balance and the like caused by reinforced leaching copper extraction; the method has high leaching rate of zinc and copper, and is beneficial to improving the recovery rate of copper and silver in the zinc hydrometallurgy process.

Description

Leaching process for improving copper recovery rate in zinc roasting ore

Technical Field

The invention relates to a leaching process for improving the copper recovery rate in zinc roasted ores, and belongs to the technical field of hydrometallurgy.

Background

The conventional zinc hydrometallurgy process is that zinc roasted ore is firstly subjected to neutral leaching, intermediate leaching slag is directly subjected to weak acid leaching, slag is sent to a pyrogenic process for volatilization, and the copper recovery rate is about 50%, so that the recovery of copper is not facilitated. Part of enterprises change weak acid leaching into low acid leaching, or increase low acid leaching after weak acid leaching, so as to improve zinc and copper leaching rate and reduce zinc leaching slag amount, but simultaneously improve leaching rate of impurities, so that acid leaching liquid contains high iron (usually 5-7 g/L) and certain concentration of germanium, arsenic and silicon, the acid leaching liquid is directly returned to a leaching system, sedimentation and filter pressing are difficult when medium leaching slurry solid separation exists, the supernatant yield is low, copper and iron are partially hydrolyzed and re-enter medium leaching slag, impurities are accumulated in the leaching system, and particularly when zinc roasting ore with high copper content is treated, the problem that copper recovery rate cannot be effectively improved is solved, and if the method for reducing medium supernatant pH is adopted to improve copper recovery rate, the medium supernatant impurities are too high to meet the purification requirement.

Therefore, research and development of a high-efficiency recovery separation technology of copper in zinc roasted ores, in particular to a leaching process of zinc roasted ores containing high copper and silver, improves the recovery rate of copper and silver, ensures that leaching liquid meeting the purification requirement is obtained, realizes reduction of conventional leaching slag and improves the recovery rate of copper and silver, and has important significance.

Disclosure of Invention

The invention provides a leaching process for improving the copper recovery rate in zinc roasted ores, which aims at solving the problem of low copper recovery in the traditional two-stage countercurrent leaching process flow, improves the copper leaching rate by strengthening copper leaching with low acid, directly recovers copper by weak acid leaching copper iron precipitation-weak leaching solution, realizes efficient recovery of copper and precipitation of iron into slag, and then utilizes neutralization and impurity removal to reduce the slag quantity and open-circuit impurities, thereby solving the problems of large middle leaching slag quantity, iron balance, impurity balance and the like caused by strengthening leaching and extracting copper.

The technical scheme for realizing the purpose of the invention is as follows:

a leaching process for improving the recovery rate of copper in zinc roasted ores comprises the following specific steps:

(1) Adding water into the roasted sand containing copper, silver and zinc to prepare mixed ore pulp;

(2) Adding an oxidant into the mixed ore pulp, simultaneously adding the zinc hydrometallurgy electrolysis waste liquid, stirring while adding, controlling the adding end point to be that the pH value of the reaction liquid is 2.0-3.0, and continuously stirring to perform weak acid leaching copper iron precipitation to produce weak leaching liquid and weak leaching slag;

(3) Recovering copper from the weak immersion liquid by adopting a displacement precipitation technology to obtain copper-rich slag and copper-precipitating liquid;

(4) Adding mixed ore pulp into copper precipitation solution, stirring while controlling the adding end point to be the pH value of the reaction solution to be 5.0-5.2, continuously stirring for reaction to perform neutralization and impurity removal, and obtaining neutralization solution and neutralization slag, wherein the neutralization solution is used as a pre-purification solution for zinc hydrometallurgy, and the neutralization slag is sent to a pyrogenic process volatilizing process of the zinc hydrometallurgy slag for conventional technology comprehensive recovery;

(5) Adding wet zinc smelting electrolytic waste liquid into weak leaching residue, stirring while adding, controlling the adding end point to be that the pH value of the reaction liquid is 0.3-0.5, and carrying out low-acid reinforced copper leaching to produce low leaching liquid and low leaching residue;

(6) The low leaching liquid can replace the wet zinc smelting electrolytic waste liquid to return to the step (2) for weak acid leaching copper to deposit iron, the low leaching slag is washed and filter-pressed to produce washing water and leaching slag, the washing water returns to the step (1) for mixing and pulping copper, silver and zinc calcine, and the leaching slag is sent to a silver selecting-pyrogenic process volatilizing process of the wet zinc smelting slag for conventional technology comprehensive recovery.

The roasted sand containing copper, silver and zinc in the step (1) contains 0.5 to 4 weight percent of copper and 0.01 to 0.05 weight percent of silver except zinc and iron.

The mixing ratio kg of the copper-silver-zinc-containing calcine and water in the step (1) is 1:1-3.

The temperature of weak acid copper leaching and iron precipitating in the step (2) is 80-90 ℃ for 1.5-2 h, and after the process starts to run, part or all of the zinc hydrometallurgy electrolysis waste liquid generated in the step (5) can be replaced by low leaching liquid to carry out weak acid copper leaching and iron precipitating.

The oxidant in the step (2) is industrial hydrogen peroxide with the mass fraction of 30%, and the addition amount of the oxidant is 3-5% of the mass of the copper-silver-zinc-containing calcine in the step (1).

The technology of the displacement precipitation in the step (3) can adopt the well-known zinc powder displacement or iron powder displacement copper precipitation, and the copper content of the obtained copper-rich slag is more than 15%.

The neutralization and impurity removal in the step (4) are carried out for 1.0 to 1.5 hours at the temperature of 60 to 80 ℃, and the mixing ratio of the copper-containing silver-zinc calcine and the copper-precipitating liquid in the mixed ore pulp is 5 to 8g to 1L.

The temperature of the low-acid enhanced copper leaching in the step (5) is 80-90 ℃ and the time is 2-2.5 h.

Aiming at the problems of low copper recovery rate in the traditional zinc hydrometallurgy process, large middle leaching slag amount, accumulated impurities and the like in the traditional enhanced leaching process, the invention improves the copper leaching rate through a two-stage countercurrent leaching process of weak acid leaching copper and low acid enhanced leaching copper; through the weak acid leaching copper iron precipitation process, the oxidation hydrolysis precipitation of iron is utilized to precipitate iron into slag while copper is leached, so that the efficient leaching of copper and the balance and the concentration control of iron in the leaching process are realized; directly recycling copper from the weak immersion liquid, avoiding copper precipitation in the solution from entering neutralization slag when the weak immersion liquid is neutralized and decontaminated, and improving the copper recovery rate; the solution meeting the requirements of zinc hydrometallurgy purification-electrowinning is obtained by neutralizing and removing impurities of the solution after copper precipitation, reducing the amount of neutralization slag and improving the liquid-solid separation performance.

The method is different from the traditional neutral leaching-weak acid leaching-low acid leaching process of zinc calcine, but the zinc calcine is directly subjected to weak acid leaching, copper is leached by weak acid, and meanwhile, iron is precipitated into slag, so that separate iron precipitation process equipment is avoided; and then the weak leaching solution is subjected to copper recovery and then neutralization, neutralization is adopted to replace the neutral leaching, the amount of the neutralization slag is far smaller than that of the neutral leaching slag, the problem of liquid-solid separation caused by the intensified leaching process is avoided, the reduction of the leaching slag is realized, the silver selection recovery rate of the subsequent leaching slag is favorably improved, and the energy consumption of the subsequent leaching slag pyrogenic process treatment is favorably reduced.

Detailed Description

The present invention will be described in further detail by way of examples, but the scope of the present invention is not limited to the above.

Example 1

A leaching process for improving the recovery rate of copper in zinc roasted ores comprises the following specific steps:

(1) Adding copper-silver-zinc calcine containing 55.14wt% of zinc, 0.52wt% of copper and 0.011wt% of silver into water according to 2L/kg, mixing and pulping, and stirring uniformly to obtain mixed ore pulp;

(2) Adding industrial hydrogen peroxide accounting for 5% of the mass fraction of copper-silver-zinc calcine and 30% of the mass fraction of copper-silver-zinc calcine into the mixed ore pulp as an oxidant, simultaneously adding wet zinc-smelting electrolysis waste liquid, stirring at the temperature of 80 ℃, controlling the adding end point to be the pH=2.46 of the reaction solution, and then, not continuously adding the wet zinc-smelting electrolysis waste liquid, continuously stirring for 2 hours, and carrying out weak acid leaching copper-iron precipitation to produce weak leaching liquid and weak leaching slag;

(3) The weak immersion liquid is subjected to copper recovery by adopting a known iron powder displacement precipitation technology to obtain copper-rich slag containing 21.09% of copper and copper-precipitating liquid;

(4) Adding the mixed ore pulp prepared in the step (1) into the copper precipitation solution, controlling the proportion of solid in the mixed ore pulp, namely, the copper precipitation solution to be 8g to 1L, stirring while adding, controlling the adding end point to be that the pH value of the reaction solution is=5.19, then, no more mixed ore pulp is added and just adding is finished, continuously stirring at 80 ℃ for reacting for 1.0h, carrying out neutralization and impurity removal, obtaining neutralization solution and neutralization slag, taking the neutralization solution as the solution before wet zinc hydrometallurgy purification, sending the neutralization slag to the wet zinc hydrometallurgy slag for conventional technology comprehensive recovery in the process of pyrogenic evaporation;

(5) Adding zinc hydrometallurgy electrolysis waste liquid into weak leaching residue, stirring while adding, controlling the adding end point to be that the pH value of the reaction solution is=0.49, and then, continuously adding the zinc hydrometallurgy electrolysis waste liquid, stirring and reacting for 2 hours at 90 ℃, and carrying out low-acid reinforced copper leaching to obtain low leaching liquid and low leaching residue;

(6) The low leaching solution can replace part or all of the zinc hydrometallurgy electrolysis waste liquid to return to the step (2) for the new round of weak acid copper leaching and iron precipitation; washing and press filtering the low leaching residue with water 2L/kg to produce washing water and leaching residue, returning the washing water to the step (1) for mixing and pulping the copper, silver and zinc calcine, and feeding the leaching residue to a silver selecting-pyrogenic process volatilizing process of the wet zinc smelting residue for conventional technology comprehensive recovery.

The implementation effect is as follows: the leaching rate of zinc is 92.15%, the recovery rate of copper is 69.38%, and the recovery rate of silver is 70.12%.

Example 2

A leaching process for improving the recovery rate of copper in zinc roasted ores comprises the following specific steps:

(1) Adding copper-silver-zinc calcine containing 52.67wt% of zinc, 1.58wt% of copper and 0.026wt% of silver into water according to the ratio of 1L/kg, mixing, and stirring uniformly to obtain mixed pulp;

(2) Adding industrial hydrogen peroxide with the mass fraction of 30% of the mass fraction of copper-silver-zinc-containing calcine into the mixed ore pulp as an oxidant, simultaneously adding wet zinc-smelting electrolysis waste liquid, stirring at the temperature of 90 ℃, controlling the adding end point to be the pH=2.07 of the reaction solution, and then, not continuously adding the wet zinc-smelting electrolysis waste liquid, continuously stirring for 1.5h, and carrying out weak acid leaching copper precipitation to produce weak leaching liquid and weak leaching slag;

(3) The weak immersion liquid is subjected to copper recovery by adopting a known iron powder displacement precipitation technology to obtain copper-rich slag containing 15.27% of copper and copper-precipitating liquid;

(4) Adding the mixed ore pulp prepared in the step (1) into the copper precipitation solution, controlling the proportion of solid in the mixed ore pulp, namely, the copper precipitation solution to be 7g to 1L, stirring while adding, controlling the adding end point to be that the pH=5.06 of the reaction solution is achieved, then, adding the mixed ore pulp, and then, continuously stirring at 60 ℃ for reacting for 1.5 hours, carrying out neutralization and impurity removal, obtaining neutralization solution and neutralization slag, wherein the neutralization solution is used as a solution before wet zinc hydrometallurgy purification and is sent to wet zinc hydrometallurgy purification-electrowinning, and the neutralization slag is sent to a pyrogenic process volatilization process of the wet zinc hydrometallurgy slag for conventional technology comprehensive recovery;

(5) Adding zinc hydrometallurgy electrolysis waste liquid into weak leaching residue, stirring while adding, controlling the adding end point to be that the pH value of the reaction solution is=0.31, then, not continuously adding the zinc hydrometallurgy electrolysis waste liquid, reacting for 2.5 hours at 80 ℃, and carrying out low-acid reinforced copper leaching to obtain low leaching liquid and low leaching residue;

(6) The low leaching solution can replace part or all of the zinc hydrometallurgy electrolysis waste liquid to return to the step (2) for the new round of weak acid copper leaching and iron precipitation; washing and press filtering the low leaching residue with water 2L/kg to produce washing water and leaching residue, returning the washing water to the step (1) for mixing and pulping the copper, silver and zinc calcine, and feeding the leaching residue to a silver selecting-pyrogenic process volatilizing process of the wet zinc smelting residue for conventional technology comprehensive recovery.

The implementation effect is as follows: the zinc leaching rate is 90.23%, the copper recovery rate is 71.58%, and the silver recovery rate is 73.64%.

Example 3

A leaching process for improving the recovery rate of copper in zinc roasted ores comprises the following specific steps:

(1) Adding water into 49.38wt% zinc, 3.96wt% copper and 0.049wt% silver-zinc calcine containing copper according to the ratio of 3L/kg, mixing, and stirring uniformly to obtain mixed pulp;

(2) Adding industrial hydrogen peroxide accounting for 4% of copper, silver and zinc calcine and accounting for 30% of the total mass of the mixed ore pulp as an oxidant, simultaneously adding wet zinc smelting electrolysis waste liquid, stirring at the temperature of 85 ℃, controlling the adding end point to be the pH=2.98 of the reaction solution, and then, not continuously adding the wet zinc smelting electrolysis waste liquid, continuously stirring for 1.6 hours, and carrying out weak acid leaching copper precipitation to produce weak leaching liquid and weak leaching slag;

(3) The weak immersion liquid is subjected to copper recovery by adopting a known iron powder displacement precipitation technology to obtain copper-rich slag containing 19.63% of copper and copper-precipitating liquid;

(4) Adding the mixed ore pulp prepared in the step (1) into the copper precipitation solution, controlling the proportion of solid in the mixed ore pulp, namely, the copper precipitation solution to be 5g to 1L, stirring while adding, controlling the adding end point to be that the pH value of the reaction solution is=5.12, then, no more mixed ore pulp is added and just adding is finished, continuously stirring at 70 ℃ for reacting for 1.2 hours, carrying out neutralization and impurity removal, obtaining neutralization solution and neutralization slag, taking the neutralization solution as the solution before wet zinc hydrometallurgy purification, sending the neutralization slag to the wet zinc hydrometallurgy slag for conventional technology comprehensive recovery in the process of pyrogenic evaporation;

(5) Adding zinc hydrometallurgy electrolysis waste liquid into weak leaching residue, stirring while adding, controlling the adding end point to be that the pH value of the reaction solution is=0.42, and then, not continuously adding the zinc hydrometallurgy electrolysis waste liquid, reacting for 2.1h at 85 ℃, and carrying out low-acid reinforced copper leaching to obtain low leaching liquid and low leaching residue;

(6) The low leaching solution can replace part or all of the zinc hydrometallurgy electrolysis waste liquid to return to the step (2) for the new round of weak acid copper leaching and iron precipitation; washing and press filtering the low leaching residue with water 2L/kg to produce washing water and leaching residue, returning the washing water to the step (1) for mixing and pulping the copper, silver and zinc calcine, and feeding the leaching residue to a silver selecting-pyrogenic process volatilizing process of the wet zinc smelting residue for conventional technology comprehensive recovery.

The implementation effect is as follows: the zinc leaching rate is 88.16%, the copper recovery rate is 75.49%, and the silver recovery rate is 78.35%.

Claims (2)

1. The leaching process for improving the copper recovery rate in the zinc roasted ore is characterized by comprising the following specific steps of:

(1) Adding water into the roasted sand containing copper, silver and zinc to prepare mixed ore pulp; the copper-silver-zinc-containing calcine comprises 0.5-4% of copper by mass and 0.01-0.05% of silver by mass;

(2) Adding an oxidant into the mixed ore pulp, simultaneously adding the zinc hydrometallurgy electrolysis waste liquid, stirring while adding, controlling the addition end point pH=2.0-3.0, and continuing stirring to perform weak acid leaching copper and iron precipitation to obtain weak leaching liquid and weak leaching slag; the oxidant is industrial hydrogen peroxide with the mass fraction of 30%, and the addition amount of the oxidant is 3-5% of the mass of the copper-silver-zinc-containing calcine obtained in the step (1);

(3) Recovering copper from the weak immersion liquid by adopting a displacement precipitation technology to obtain copper-rich slag and copper-precipitating liquid;

(4) Adding the mixed ore pulp in the step (1) into copper precipitation liquid, stirring while adding, controlling the end point pH=5.0-5.2 of addition, and then not adding any more, continuing stirring to perform neutralization and impurity removal, and obtaining neutralization liquid and neutralization slag, wherein the neutralization liquid is used as a liquid before purification of zinc hydrometallurgy, and the neutralization slag is sent to a pyrogenic process volatilizing process of the zinc hydrometallurgy slag for comprehensive recovery;

(5) Adding wet zinc smelting electrolytic waste liquid into weak leaching residue, stirring while adding, controlling the addition end point pH=0.3-0.5, and then not continuing to add, and carrying out low-acid reinforced copper leaching to produce low leaching liquid and low leaching residue;

(6) The low-leaching liquid is used for replacing the wet zinc smelting electrolysis waste liquid to return to the step (2) for the weak acid leaching copper-precipitation iron; washing and press-filtering the low leaching residues to produce washing water and leaching residues, returning the washing water to the step (1) for mixing and pulping the copper, silver and zinc calcine, and feeding the leaching residues to a silver selection-pyrogenic process volatilizing process of the zinc hydrometallurgy residues for comprehensive recovery;

the temperature of weak acid copper leaching and iron depositing in the step (2) is 80-90 ℃ and the time is 1.5-2 h;

the neutralization and impurity removal step (4) is to react for 1.0-1.5 hours at the temperature of 60-80 ℃, and the mixing ratio of the copper-containing silver-zinc calcine and the copper-precipitating liquid in the mixed ore pulp is 5-8 g/1L;

the temperature of the low-acid enhanced copper leaching in the step (5) is 80-90 ℃ and the time is 2-2.5 h.

2. The leaching process for improving the copper recovery rate in the zinc roasted ore according to claim 1, wherein the mixing ratio kg of the copper-containing silver-zinc roasted ore and water in the step (1) is 1:1-3.