Method for improving utilization rate of manganese in zinc electrodeposition anode slime

Abstract

The invention discloses a method for improving the utilization rate of manganese in zinc electrodeposition anode slime. The method comprises the following steps: firstly, mixing zinc electrodeposition anode mud with water, and then carrying out wet ball milling to obtain anode mud slurry; the replaced liquid and the waste liquid are added into the obtained anode mud slurry to be mixed, and heating and stirring are conducted for an oxidation-reduction reaction; after the reaction, hydrogen peroxide is added for a secondary reduction reaction with manganese dioxide in the anode slime, and Mn < 4 + > is reduced into Mn < 2 + >; and after the reaction is finished, carrying out filter pressing on the obtained solution, returning filtrate to a main system, and feeding filter residues to a rotary kiln for treatment. According to the method, the zinc electrodeposition anode slime is recycled, manganese in the slag is converted into liquid, and the liquid is returned to a main system as a manganese sulfate solution. The method is low in cost, small in investment, simple in technological process and high in manganese recovery rate, impurities influencing system stability are not introduced, and efficient recycling of valuable metal in the zinc electrodeposition anode slime is achieved.

Description

I. Technical Field:

[0001] The present invention belongs to the technical field of zinc smelting in the non-ferrous metal smelting industry, and particularly relates to a method for recovering manganese from zinc electrowinning anode slime as raw material, reducing tetravalent manganese to divalent manganese and returning it to the zinc electrowinning system, that is, a method for improving the utilization rate of manganese in zinc electrowinning anode slime. II. Background Art:

[0002] During the electrowinning process in a hydrometallurgical zinc plant, a large amount of anode slime is generated at the anode. The main components of this anode slime are manganese, lead, and strontium, and also contain a small amount of silver. Among them, lead and silver are valuable resources that can be recycled and utilized.

[0003] During the zinc electrowinning process, the divalent manganese ions in the solution need to be maintained within a certain range. When the manganese content is low, the anode slime attached to the surface of the anode plate will fall off, and the lead in the anode slime will enter the electrolyte, ultimately affecting the quality of the precipitated zinc. At the same time, during the zinc electrowinning process, the divalent manganese ions in the electrolyte are depleted and enter the anode slime. To maintain the stability of manganese in the new solution, manganese powder and manganese carbonate need to be added. Therefore, there is an urgent need to develop a new process to improve the utilization rate of manganese in the anode slime, return manganese to the system, and reduce losses.

[0004] The prices of manganese ore and manganese metal have been continuously rising. Therefore, manganese and its compounds have great economic value and broad market prospects. Therefore, the research on the recycling technology of manganese metal in zinc electrowinning anode slime has high economic and social value.

[0005] At present, in the conventional hydrometallurgical zinc smelting process in the industry, the electrowinning anode slime produced is mainly sent to the roasting leaching oxidation tank to recover manganese, but the manganese utilization rate of this method is relatively low, only about 25%. Most of the manganese enters the slag treatment system with the leaching residue, resulting in a large loss. III. Summary of the Invention:

[0006] The technical problem to be solved by the present invention is: aiming at the treatment status of the existing recycling methods for zinc electrowinning anode slime and the technical problem of low manganese utilization rate, the present invention provides a method for improving the utilization rate of manganese in zinc electrowinning anode slime. By using the technical scheme of the present invention to recycle and treat zinc electrowinning anode slime, the manganese leaching efficiency can reach more than 85%, the manganese content in the slag can be reduced to less than 1.5%, effectively improving the manganese utilization rate, reducing manganese loss, and stabilizing the production of the electrowinning process; by using the present invention to treat zinc electrowinning anode slime, it has low cost, less investment, simple process flow, high manganese recovery rate, and will not introduce impurities that affect the system stability, thus realizing the efficient recycling and utilization of valuable metals in zinc electrowinning anode slime.

[0007] To solve the above problems, the technical scheme adopted by the present invention is:

[0008] The present invention provides a method for improving the utilization rate of manganese in zinc electrowinning anode slime, and the method comprises the following steps:

[0009] 1) Wet ball milling: Mix zinc electrowinning anode mud and water, and after mixing, feed them into a ball mill for wet ball milling to obtain an anode mud slurry.

[0010] 2) Redox reaction: Add the post - replacement solution and waste liquid to the anode mud slurry obtained in step 1) for mixing, and heat and stir for a redox reaction.

[0011] 3) Secondary reduction: After the reaction in step 2), then add hydrogen peroxide to react with manganese dioxide in the anode mud for a secondary reduction reaction to reduce Mn 4+ to Mn 2+ ;

[0012] 4) Pressure filtration: Filter the solution obtained after the reaction in step 3) by pressure filtration. The filtrate is returned to the main system, and the filter residue is sent to a rotary kiln for treatment.

[0013] According to the above - mentioned method for improving the utilization rate of manganese in zinc electrowinning anode mud, the zinc electrowinning anode mud described in step 1) is the anode mud deposited at the bottom of the electrowinning cell and / or on the electrowinning plate.

[0014] According to the above - mentioned method for improving the utilization rate of manganese in zinc electrowinning anode mud, when mixing zinc electrowinning anode mud and water in step 1), the volume ratio of zinc electrowinning anode mud to water is 1:1 - 1.5.

[0015] According to the above - mentioned method for improving the utilization rate of manganese in zinc electrowinning anode mud, the post - replacement solution described in step 2) is the solution after indium precipitation in the zinc oxide treatment system, and the content of divalent iron in it is 8 - 15 g / L; the waste liquid is the liquid produced after the end of zinc electrowinning, and the content of H2SO4 in the waste liquid is 180 - 200 g / L.

[0016] According to the above - mentioned method for improving the utilization rate of manganese in zinc electrowinning anode mud, the volume ratio of the post - replacement solution to the anode mud slurry added in step 2) is 3 - 5:1; the volume ratio of the waste liquid to the anode mud slurry added is 1:1.

[0017] According to the above - mentioned method for improving the utilization rate of manganese in zinc electrowinning anode mud, when conducting the redox reaction in step 2), the reaction temperature is 80 - 90 °C and the reaction time is 1.5 - 2 h.

[0018] According to the above - mentioned method for improving the utilization rate of manganese in zinc electrowinning anode mud, the addition amount of hydrogen peroxide in step 3) is 700 - 800 L of hydrogen peroxide added to 20 m3 of anode mud slurry.

[0019] According to the above - mentioned method for improving the utilization rate of manganese in zinc electrowinning anode mud, when conducting the secondary reduction reaction in step 3), the reaction temperature is 65 - 70 °C and the reaction time is 1 - 1.5 h.

[0020] According to the above method for improving the utilization rate of manganese in zinc electrowinning anode slime, the manganese content in the filtrate obtained in step 4) is 10-15 g / L, and the divalent iron is <1 g / L; the manganese content in the obtained filter residue is <1.5%, zinc is 5-10%, moisture is 25-30%, and silver is 200-400 g / t.

[0021] In the technical solution of the present invention, first, the zinc electrowinning anode slime is wet ball-milled to reduce its particle size and increase the specific surface area, and then the replacement post-liquid rich in divalent iron in the zinc oxide system and the zinc electrowinning waste liquid are added to react in an acidic environment to reduce tetravalent manganese in the anode slime to divalent manganese. To ensure the full utilization of manganese in the anode slime, hydrogen peroxide solution is added in the later stage of the reaction to further reduce the manganese content in the anode slime. After the reaction, pressure filtration is carried out, and after manganese is leached, it returns to the hydrometallurgical zinc system with the filtrate.

[0022] The positive and beneficial effects of the present invention:

[0023] 1. Using the technical solution of the present invention to treat zinc electrowinning anode slime can effectively recover manganese in the zinc electrowinning anode slime and improve the manganese metal recovery rate.

[0024] 2. Using the technical solution of the present invention to recycle and treat zinc electrowinning anode slime, after manganese is recovered, it enters the solution and is reused in the electrowinning system, reducing the amount of manganese supplemented in the system and the amount of purchased manganese carbonate.

[0025] 3. Using the technical solution of the present invention to recycle and treat zinc electrowinning anode slime, after manganese in the anode slime is recovered, lead and silver are enriched and the proportion increases, which is more conducive to the subsequent recovery of metals such as lead and silver.

[0026] In summary, using the present invention to treat zinc electrowinning anode slime, after the tank reaction, the manganese content in the anode slime is reduced from 33% to less than 1.5%, the manganese leaching efficiency reaches more than 85%, the daily recoverable manganese metal amount can be increased by 750 kg, which can effectively improve the manganese utilization rate, reduce manganese loss, stabilize the production of the electrowinning process, and at the same time, the daily addition amount of auxiliary manganese powder (main component MnO2) can be reduced by 1.36 tons (1800 yuan / t), and the annual production cost can be saved by 860,000 yuan. Therefore, the present invention has low operating cost, less investment, simple process flow, high manganese recovery rate, and does not introduce impurities that affect system stability, thus realizing the efficient recovery and utilization of valuable metals in zinc electrowinning anode slime. IV. Specific implementation manners:

[0027] The following further elaborates the content of the present invention in combination with specific embodiments, but does not limit the scope of protection of the technical solution of the present invention.

[0028] In the following examples, the zinc electrowinning anode slime used is the anode slime deposited on the electrowinning plates at the bottom of the electrowinning cell; the post-replacement solution is the solution after indium precipitation in the zinc oxide treatment system, and the content of divalent iron in the solution after indium precipitation is 8 - 15 g / L; the waste liquid is the liquid produced after the zinc electrowinning is completed, and the content of H2SO4 in the waste liquid is 180 - 200 g / L.

[0029] Example 1:

[0030] The method for improving the utilization rate of manganese in zinc electrowinning anode slime of the present invention is detailed as follows:

[0031] 1) Wet ball milling: Mix the zinc electrowinning anode slime and production water in a volume ratio of 1:1. Both the zinc electrowinning anode slime and water are 10 m3. After mixing, feed them into a ball mill for wet ball milling. The mass ratio of the steel balls inside the wet ball mill to the zinc electrowinning anode slime is 20:1. The rotation speed of the ball mill is 200 rpm, and the ball milling time is 60 minutes. After ball milling, an anode mud slurry is obtained;

[0032] 2) Redox reaction: Add the obtained anode mud slurry into a conversion tank, and then add 70 m3 of the post-replacement solution (n(Fe 2+ ) : n(Mn 4+ ) = 3:1) into the conversion tank, and add 20 m3 of the waste liquid. The addition amount of the waste liquid to the volume of the anode mud slurry is 1:1. Keep the liquid-solid ratio in the conversion tank at 20:1 and the acidity at 20 g / L. Heat to 80 °C and stir (the stirring intensity is 300 rpm). Conduct the redox reaction for 90 minutes, and then lower the temperature to 65 °C;

[0033] 3) Secondary reduction: After the reaction solution in step 2) is cooled, then add 700 L of hydrogen peroxide and continue the secondary reduction reaction for 60 min;

[0034] 4) Pressure filtration: Filter the solution obtained after the reaction in step 3). The filtrate is returned to the main system, and the filter cake is sent to a rotary kiln for treatment.

[0035] Through the recovery and treatment of zinc electrowinning anode slime in this example, the manganese recovery rate reaches 85.96%. In the obtained filtrate, the manganese content is 12.93 g / L and the divalent iron content is 0.56 g / L; in the obtained filter cake, the manganese content is 0.98%, the zinc content is 7.23%, the moisture content is 26.95%, and the silver content is 335 g / t.

[0036] Example 2:

[0037] The method for improving the utilization rate of manganese in zinc electrowinning anode slime of the present invention is detailed as follows:

[0038] 1) Wet ball milling: Mix zinc electrowinning anode mud and production water in a volume ratio of 1:1. Both the anode mud and water are 10 m3. After mixing, feed them into a ball mill for wet ball milling. The mass ratio of steel balls to zinc electrowinning anode mud inside the wet ball mill is 20:1. The rotational speed of the ball mill is 200 rpm, and the ball milling time is 60 minutes. After ball milling, an anode mud slurry is obtained.

[0039] 2) Redox reaction: Add the obtained anode mud slurry to a conversion tank, and then add 70 m3 of the replaced solution (n(Fe 2+ ): n(Mn 4+ ) = 3:1) to the conversion tank, and add 20 m3 of waste liquid. The addition amount of the waste liquid to the volume of the anode mud slurry is 1:1. Keep the liquid-solid ratio in the conversion tank at 20:1 and the acidity at 25 g / L. Heat to 90 °C and stir (stirring intensity is 300 rpm). Conduct the redox reaction for 120 minutes, and then cool the temperature to 70 °C.

[0040] 3) Secondary reduction: After the reaction solution in step 2) is cooled, then add 700 L of hydrogen peroxide and continue the secondary reduction reaction for 90 min.

[0041] 4) Pressure filtration: Filter the solution obtained after the reaction in step 3). The filtrate is returned to the main system, and the filter cake is sent to a rotary kiln for treatment.

[0042] By recycling and treating zinc electrowinning anode mud through this example, the manganese recovery rate reaches 86.43%. In the obtained filtrate, the manganese content is 13.27 g / L, and the divalent iron content is 0.26 g / L. In the obtained filter cake, the manganese content is 1.23%, the zinc content is 5.56%, the moisture content is 28.47%, and the silver content is 286 g / t.

[0043] In summary, by recycling and treating zinc electrowinning anode mud through the method of the present invention, the manganese in the slag is converted into the liquid and returned to the main system as a manganese sulfate solution. The present invention has low cost, less investment, a simple process flow, a high manganese recovery rate, and does not introduce impurities that affect the system stability, realizing the efficient recycling and utilization of valuable metals in zinc electrowinning anode mud.

Claims

1. A method for improving the utilization rate of manganese in zinc electrowinning anode slime, characterized in that, The method includes the following steps: 1) Wet ball milling: Mix zinc electrowinning anode slime and water, and after mixing, feed them into a ball mill for wet ball milling to obtain an anode mud liquid; 2) Redox reaction: Add the post-replacement liquid and waste liquid to the anode mud liquid obtained in step 1) for mixing, and heat and stir for a redox reaction; 3) Secondary reduction: After the reaction in step 2), hydrogen peroxide is then added to conduct a secondary reduction reaction with manganese dioxide in the anode slime to reduce Mn 4+ to Mn 2+ ; 4) Pressure filtration: Filter the solution obtained after the reaction in step 3) by pressure filtration. The filtrate is returned to the main system, and the filter residue is sent to a rotary kiln for treatment.

2. The method for improving the utilization rate of manganese in zinc electrowinning anode mud according to claim 1, characterized in that: The zinc electrowinning anode slime mentioned in step 1) is the anode slime deposited at the bottom of the electrowinning cell and / or on the electrowinning plate.

3. The method for improving the utilization rate of manganese in zinc electrowinning anode slime according to claim 1, wherein: When mixing the zinc electrowinning anode slime and water in step 1), the volume ratio of the zinc electrowinning anode slime to water is 1:1 to 1.

5.

4. The method for improving the utilization rate of manganese in zinc electrowinning anode slime according to claim 1, wherein: The post-replacement liquid mentioned in step 2) is the liquid after indium precipitation in the zinc oxide treatment system, and the content of divalent iron in it is 8 - 15 g / L; the waste liquid is the liquid produced after the end of zinc electrowinning, and the content of H2SO4 in the waste liquid is 180 - 200 g / L.

5. The method for improving the utilization rate of manganese in zinc electrowinning anode slime according to claim 1, characterized in that: In step 2), the volume ratio of the post-replacement liquid to the anode mud liquid added is 3 - 5:1; the volume ratio of the waste liquid to the anode mud liquid added is 1:

1.

6. The method for improving the utilization rate of manganese in zinc electrowinning anode mud according to claim 1, wherein: In step 2) during the redox reaction, the reaction temperature is 80 - 90 °C and the reaction time is 1.5 - 2 h.

7. The method for improving the utilization rate of manganese in zinc electrowinning anode slime according to claim 1, wherein: In step 3), the addition amount of hydrogen peroxide is 700 - 800 L of hydrogen peroxide added to 20 m3 of anode mud liquid.

8. The method for improving the utilization rate of manganese in zinc electrowinning anode slime according to claim 1, characterized in that: In step 3) during the secondary reduction reaction, the reaction temperature is 65 - 70 °C and the reaction time is 1 - 1.5 h.

9. The method for improving the utilization rate of manganese in zinc electrowinning anode slime according to claim 1, wherein: In step 4), the manganese content in the obtained filtrate is 10 - 15 g / L, and the divalent iron < 1 g / L; the manganese content in the obtained filter residue is < 1.5%, zinc is 5 - 10%, moisture is 25 - 30%, and silver is 200 - 400 g / t.