CN115011810B - A leaching process to improve copper recovery rate in zinc roasted ores - 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

A leaching process to improve copper recovery rate in zinc roasted ores

Technical field

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

Background technique

In the conventional hydrometallurgical zinc smelting process, the zinc roasting ore is first subjected to neutral leaching, the medium leaching residue is directly leached with weak acid, and the slag is sent to the fire volatilization process. The copper recovery rate is about 50%, which is not conducive to the recovery of copper. Some companies have changed weak acid leaching to low acid leaching, or added low acid leaching after weak acid leaching. The purpose is to increase the leaching rate of zinc and copper and reduce the amount of zinc leaching residue. However, it also increases the leaching rate of impurities, resulting in acid leaching liquid It contains high iron (usually 5-7g/L) and a certain concentration of germanium, arsenic, and silicon. The acid leaching liquid is directly returned to the leaching system. It is difficult to settle and filter during solid separation of the leaching slurry, and the supernatant is The yield is low. Partial hydrolysis of copper and iron re-enters the intermediate leaching residue, and impurities accumulate in the leaching system. Especially when dealing with zinc roasted ores with high copper content, the copper recovery rate cannot be effectively improved. If the pH of the intermediate supernatant is reduced, Methods to improve the copper recovery rate will also lead to excessive impurities in the supernatant, which cannot meet the purification requirements.

Therefore, it is necessary to research and develop efficient recovery and separation technology of copper in zinc roasted ores, especially the leaching process of zinc roasted ores with high copper and silver content, to improve the recovery rate of copper and silver, while ensuring that the leachate that meets the purification requirements is obtained, and conventional leaching residues are achieved It is of great significance to reduce the amount of copper and silver and increase the recovery rate of copper and silver.

Contents of the invention

The present invention provides a leaching process that improves the recovery rate of copper in zinc roasted ores. Aiming at the problem of low copper recovery in the traditional two-stage countercurrent leaching process, the leaching rate of copper is improved by strengthening copper leaching with low acid, and iron is precipitated by weak acid leaching of copper - The weak leaching liquid directly recovers copper, achieving efficient recovery of copper and precipitation of iron into slag, and then uses neutralization and impurity removal to reduce the amount of slag and open-circuit impurities, thereby solving the problems of large slag volume, iron balance, and iron balance caused by intensive leaching to extract copper. Impurity balance and other issues.

The technical solutions to achieve the object of the present invention are as follows:

A leaching process to improve the copper recovery rate in zinc roasted ores. The specific steps are as follows:

(1) Add copper-silver-zinc calcined sand to water to prepare a mixed slurry;

(2) Add oxidant to the mixed slurry, and add wet zinc smelting electrolytic waste liquid at the same time, stir while adding, control the addition end point to the pH value of the reaction solution to be 2.0 to 3.0, continue stirring to perform weak acid leaching of copper and iron, and output Weak leaching liquid and weak leaching residue;

(3) Use displacement precipitation technology to recover copper from the weak leaching solution to obtain copper-rich slag and copper precipitation liquid;

(4) Add the mixed slurry to the copper precipitation liquid, stir while adding, control the addition end point to the pH value of the reaction solution to be 5.0 to 5.2, continue to stir the reaction to neutralize and remove impurities, and produce neutralized liquid, neutralized slag, and neutralized slag. The neutralizing liquid is used as the pre-purification liquid for hydro-zinc smelting, and the neutralized slag is sent to the fire volatilization process of hydro-zinc smelting slag for comprehensive recovery using conventional technologies;

(5) Add wet zinc smelting electrolytic waste liquid to the weak leaching residue, stir while adding, control the addition end point to the pH value of the reaction solution to be 0.3-0.5, perform low-acid enhanced copper leaching, and produce low-leaching liquid and low-leaching liquid. slag;

(6) The low leaching liquid can replace the wet zinc smelting electrolysis waste liquid return step (2) for weak acid leaching of copper and iron. The low leaching slag is washed and filtered to produce washing water and leaching slag. The washing water returns step ( 1) It is used for mixing copper, silver and zinc baking sand and slurrying, and the leaching residue is sent to the silver selection-fire volatilization process of hydrometallurgical zinc slag for comprehensive recycling using conventional technologies.

Step (1) The copper-silver-zinc baked sand contains, in addition to zinc and iron, 0.5 to 4 wt% of copper and 0.01 to 0.05 wt% of silver.

Step (1) The mixing ratio kg:L of copper-silver-zinc calcined sand and water is 1:1~3.

In step (2), the temperature of weak acid leaching of copper and iron is 80 to 90°C, and the time is 1.5 to 2 hours. After the process starts running, the low leaching liquid produced in step (5) can be used to replace part or all of the wet zinc smelting electrolytic waste liquid. Carry out weak acid leaching of copper and iron.

The oxidant in step (2) is industrial hydrogen peroxide with a mass fraction of 30%, and the amount of oxidant added is 3 to 5% of the mass of the copper-silver-zinc baked sand in step (1).

The replacement precipitation technology of step (3) can use the well-known zinc powder replacement or iron powder replacement to deposit copper, and the copper-rich slag obtained contains more than 15% copper.

The neutralization and impurity removal in step (4) is carried out at 60-80°C for 1.0-1.5 hours. The mixing ratio of copper-silver-zinc calcined sand and copper precipitation liquid in the mixed slurry is 5-8g:1L.

In step (5), the temperature of low-acid strengthened copper immersion is 80 to 90°C, and the time is 2 to 2.5 hours.

This invention aims at the problems of low copper recovery rate in the traditional hydrometallurgical zinc smelting process and the large amount of intermediate leaching residue and accumulation of impurities in the traditional enhanced leaching process. It improves the efficiency of copper leaching through a two-stage countercurrent leaching process of weak acid copper leaching and low acid enhanced copper leaching. Copper leaching rate; through the weak acid leaching copper and iron leaching process, while leaching copper, the oxidation and hydrolysis precipitation of iron is used to precipitate the iron into the slag, achieving efficient leaching of copper and iron balance and iron concentration control during the leaching process; the weak acid leaching process will The immersion liquid directly recovers copper to avoid the copper in the solution from precipitating into the neutralization slag during neutralization and impurity removal in the weak immersion liquid, thereby improving the copper recovery rate; by neutralizing and removing impurities from the copper immersion liquid, the amount of neutralization slag is reduced and the improvement Liquid-solid separation performance to obtain a solution that meets the purification and electrowinning requirements of zinc hydrometallurgy.

This invention is different from the traditional neutral leaching-weak acid leaching-low acid leaching process of zinc roasting sand. Instead, the zinc roasting sand is directly leached with weak acid. While copper is leached with weak acid, iron is precipitated into the slag, thus avoiding separate precipitation. Iron process equipment; then the weak leaching liquid is recovered for copper and then neutralized. Neutralization is used instead of medium leaching. The amount of neutralized slag is much less than that of medium leaching slag, which avoids the problem of liquid-solid separation caused by the enhanced leaching process and achieves The reduction of the leaching slag is conducive to increasing the recovery rate of subsequent silver selection from the leaching slag and reducing the energy consumption of the subsequent fire treatment of the leaching slag.

Detailed ways

The present invention will be further described in detail through examples below, but the protection scope of the present invention is not limited to the content described.

Example 1

A leaching process to improve the copper recovery rate in zinc roasted ores. The specific steps are as follows:

(1) Add 2L/kg of copper-containing silver-zinc calcined sand containing 55.14wt% zinc, 0.52wt% copper, and 0.011wt% silver into water to mix and slurry, stir and mix to obtain a mixed slurry;

(2) Add 30% industrial hydrogen peroxide containing 5% of the mass of copper, silver and zinc calcined sand to the mixed slurry as an oxidant, and simultaneously add wet zinc smelting electrolytic waste liquid, stir while adding at 80°C, and control the addition end point After the reaction solution pH=2.46, the wet zinc smelting electrolytic waste liquid is no longer added, and the stirring is continued for 2 hours to carry out weak acid leaching of copper and iron to produce weak leaching liquid and weak leaching slag;

(3) The weak leaching liquid adopts the well-known iron powder replacement precipitation technology to recover copper, and obtain a copper-rich slag containing 21.09% copper and a copper precipitation liquid;

(4) Add the mixed slurry prepared in step (1) to the copper slurry, control the ratio of solids in the mixed slurry: copper slurry to 8g:1L, stir while adding, and control the addition end point to the pH of the reaction solution = 5.19. Then add the mixed slurry until it is completely added, continue to stir and react for 1.0 hours at 80°C, neutralize and remove impurities, and produce neutralized liquid and neutralized slag. The neutralized liquid is sent to the wet method as the pre-purification liquid for zinc smelting. Zinc smelting purification - electroplating, neutralization slag is sent to the fire volatilization process of hydrometallurgy zinc slag for comprehensive recovery with conventional technology;

(5) Add wet zinc smelting electrolytic waste liquid to the weak leaching residue, stir while adding, control the addition end point to the reaction solution pH = 0.49, then no longer add wet zinc smelting electrolytic waste liquid, and continue stirring at 90°C React for 2 hours, perform low-acid enhanced copper leaching, and produce low-leaching liquid and low-leaching slag;

(6) The low leaching liquid can replace part or all of the wet zinc smelting electrolytic waste liquid and return to step (2) for a new round of weak acid leaching of copper and iron; add 2L/kg of water to the low leaching residue for washing and filtering to produce The washing water and leaching residue are discharged, and the washing water is returned to step (1) for mixing copper, silver, and zinc baking sand to make slurry, and the leaching residue is sent to the silver selection-fire volatilization process of wet zinc smelting slag for comprehensive recovery using conventional technologies.

Implementation results: zinc leaching rate 92.15%, copper recovery rate 69.38%, silver recovery rate 70.12%.

Example 2

A leaching process to improve the copper recovery rate in zinc roasted ores. The specific steps are as follows:

(1) Add water to the copper-silver-zinc calcined sand containing 52.67wt% zinc, 1.58wt% copper, and 0.026wt% silver to mix the slurry with water at a rate of 1L/kg, stir and mix to obtain a mixed slurry;

(2) Add 30% industrial hydrogen peroxide containing 3% of the mass of copper, silver and zinc calcined sand to the mixed slurry as an oxidant, and add the wet zinc smelting electrolytic waste liquid at the same time, stir while adding at 90°C, and control the addition end point After the reaction solution pH=2.07, the wet zinc smelting electrolytic waste liquid is no longer added, and the stirring is continued for 1.5 hours to carry out weak acid leaching of copper and iron to produce weak leaching liquid and weak leaching slag;

(3) The weak leaching liquid adopts the well-known iron powder replacement precipitation technology to recover copper, and obtain a copper-rich slag containing 15.27% copper and a copper precipitation liquid;

(4) Add the mixed slurry prepared in step (1) to the copper slurry, control the ratio of solids in the mixed slurry: copper slurry to 7g:1L, stir while adding, and control the addition end point to the pH of the reaction solution = 5.06. Then add the mixed slurry until it is completely added, continue to stir and react for 1.5 hours at 60°C, neutralize and remove impurities, and produce neutralized liquid and neutralized slag. The neutralized liquid is sent to the wet method as the pre-purification liquid of wet zinc smelting. Zinc smelting purification - electroplating, neutralization slag is sent to the fire volatilization process of hydrometallurgy zinc slag for comprehensive recovery with conventional technology;

(5) Add wet zinc smelting electrolytic waste liquid to the weak leaching residue, stir while adding, control the addition end point to the reaction solution pH = 0.31, then no longer add wet zinc smelting electrolytic waste liquid, react at 80°C for 2.5 h, perform low-acid enhanced copper leaching to produce low-leaching liquid and low-leaching slag;

(6) The low leaching liquid can replace part or all of the wet zinc smelting electrolytic waste liquid and return to step (2) for a new round of weak acid leaching of copper and iron; add 2L/kg of water to the low leaching residue for washing and filtering to produce The washing water and leaching residue are discharged, and the washing water is returned to step (1) for mixing copper, silver, and zinc baking sand to make slurry, and the leaching residue is sent to the silver selection-fire volatilization process of wet zinc smelting slag for comprehensive recovery using conventional technologies.

Implementation results: zinc leaching rate 90.23%, copper recovery rate 71.58%, silver recovery rate 73.64%.

Example 3

A leaching process to improve the copper recovery rate in zinc roasted ores. The specific steps are as follows:

(1) Add 3L/kg of water to the copper-silver-zinc calcined sand containing 49.38wt% zinc, 3.96wt% copper, and 0.049wt% silver to mix and slurry, stir and mix to obtain a mixed slurry;

(2) Add 30% industrial hydrogen peroxide containing 4% of the mass of copper, silver and zinc calcined sand to the mixed slurry as an oxidant, and simultaneously add wet zinc smelting electrolytic waste liquid, stir while adding at 85°C, and control the addition end point After the reaction solution pH=2.98, the wet zinc smelting electrolytic waste liquid is no longer added, and the stirring is continued for 1.6 hours to carry out weak acid leaching of copper and iron to produce weak leaching liquid and weak leaching slag;

(3) The weak leaching liquid adopts the well-known iron powder replacement precipitation technology to recover copper, and obtain a copper-rich slag containing 19.63% copper and a copper precipitation liquid;

(4) Add the mixed slurry prepared in step (1) to the copper slurry, control the ratio of solids in the mixed slurry: copper slurry to 5g:1L, stir while adding, and control the addition end point to the pH of the reaction solution = 5.12. Then add the mixed slurry until it is completely added, continue stirring and reacting at 70°C for 1.2 hours, neutralize and remove impurities, and produce neutralized liquid and neutralized slag. The neutralized liquid is sent to the wet method as the pre-purification liquid for zinc smelting. Zinc smelting purification - electroplating, neutralization slag is sent to the fire volatilization process of hydrometallurgy zinc slag for comprehensive recovery with conventional technology;

(5) Add wet zinc smelting electrolytic waste liquid to the weak leaching residue, stir while adding, control the addition end point to the reaction solution pH = 0.42, then no longer add wet zinc smelting electrolytic waste liquid, and react at 85°C for 2.1 h, perform low-acid enhanced copper leaching to produce low-leaching liquid and low-leaching slag;

(6) The low leaching liquid can replace part or all of the wet zinc smelting electrolytic waste liquid and return to step (2) for a new round of weak acid leaching of copper and iron; add 2L/kg of water to the low leaching residue for washing and filtering to produce The washing water and leaching residue are discharged, and the washing water is returned to step (1) for mixing copper, silver, and zinc baking sand to make slurry, and the leaching residue is sent to the silver selection-fire volatilization process of wet zinc smelting slag for comprehensive recovery using conventional technologies.

Implementation results: zinc leaching rate 88.16%, copper recovery rate 75.49%, silver recovery rate 78.35%.

Claims (2)

1. A leaching process to improve the copper recovery rate in zinc roasted ores, which is characterized in that the specific steps are as follows: (1) Add water to the copper-containing silver-zinc roasted sand to prepare a mixed slurry; the mass percentage content of copper in the copper-containing silver-zinc roasted sand is 0.5~4%, and the mass percentage content of silver is 0.01~0.05%; (2) Add oxidant to the mixed slurry, and add wet zinc smelting electrolytic waste liquid at the same time, stir while adding, control the addition end point pH = 2.0~3.0, no longer add, continue stirring to perform weak acid leaching of copper and iron, and produce Weak leaching liquid and weak leaching residue are produced; the oxidant is industrial hydrogen peroxide with a mass fraction of 30%, and the amount of oxidant added is 3~5% of the mass of the copper-silver-zinc baked sand in step (1); (3) Use the weak leaching liquid to recover copper using displacement precipitation technology to obtain copper-rich slag and copper precipitation liquid; (4) Add the mixed slurry in step (1) to the copper immersion liquid, stir while adding, control the addition endpoint pH = 5.0~5.2, then add no more, continue stirring the reaction to neutralize and remove impurities, and produce a neutralized liquid. , neutralized slag, the neutralized liquid is used as the pre-purification liquid for hydro-zinc smelting, and the neutralized slag is sent to the fire volatilization process of hydro-zinc smelting slag for comprehensive recovery; (5) Add wet zinc smelting electrolytic waste liquid to the weak leaching residue, stir while adding, control the addition end point pH = 0.3~0.5, and then no longer add, carry out low-acid enhanced copper leaching, and produce low leaching liquid and low leaching residue; (6) The low leaching liquid replaces the wet zinc smelting electrolytic waste liquid and returns to the step (2) for weak acid leaching of copper and iron; the low leaching slag is washed and filtered to produce washing water and leaching residue, and the washing water returns to the step (1) ) is used for mixing copper, silver and zinc roasting sand, and the leached slag is sent to the silver selection-fire volatilization process of hydrometallurgical zinc slag for comprehensive recovery; Step (2) The temperature of weak acid leaching of copper and iron is 80~90℃, and the time is 1.5~2h; Step (4) Neutralization and impurity removal are carried out at 60~80°C for 1.0~1.5h. The mixing ratio of copper-silver-zinc calcined sand and copper precipitation liquid in the mixed slurry is 5~8g:1L; In step (5), the temperature of low-acid strengthened copper immersion is 80~90℃, and the time is 2~2.5h. 2. The leaching process for improving copper recovery rate in zinc roasted ores according to claim 1, characterized in that the mixing ratio kg:L of copper-containing silver-zinc roasted sand and water in step (1) is 1:1~3.