Method for producing chlorinated electrodeposited cobalt from high-iron silicon raw material

Abstract

The invention discloses a method for producing chlorinated electrodeposited cobalt from a high-iron-silicon raw material. The method comprises the working procedures of slurrying dissolution, pre-removal of iron and silicon from the raw material, iron removal, extraction and impurity removal, nickel-cobalt separation, purification and impurity removal, electrodeposition and the like. According to the method, industrial sulfuric acid, sodium hydrogen sulfite, sodium carbonate, alkali and the like are added, proper reaction temperature, reaction time, reaction node pH and other factors are controlled, a pure cobalt chloride solution is obtained, and electrodeposited cobalt is obtained after electrodeposition. The cobalt content of the iron slag is lower than 0.2%; nickel sulfate contains less than or equal to 0.05 g / L of cobalt; the copper chloride after extraction contains less than or equal to 0.5 g / L of cobalt, more than or equal to 7g / L of copper and more than or equal to 10g / L of manganese. Precious metals such as copper and manganese are enriched in a copper chloride solution for external application. The method has the advantages that the cobalt leaching rate is high, the grade rate of finished product cobalt is high, and iron and silicon in the raw materials are effectively removed.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for producing chloride electrodeposition cobalt from high-iron silicon raw materials. Background Art

[0002] As an important material, electrolytic cobalt is widely used in the fields of batteries, catalysts, materials and chemicals. At present, the production of electrolytic cobalt is mainly based on the chloride system, but the raw materials contain high iron and silicon content, and during the leaching process of the raw materials, the nickel content in the solution is higher than the cobalt content. During the electrolytic process, iron and nickel will be electrolytically deposited before cobalt, resulting in poor quality of cobalt plates and low current efficiency. Therefore, further research and improvement in the production of electrolytic cobalt is urgently required. Summary of the invention

[0003] The object of the present invention is to provide a method for producing chloride electrowinning cobalt from high iron silicon raw materials to solve the problems raised in the above background technology.

[0004] The present invention adopts the following technical solution: A method for producing chloride electrolytic cobalt from high iron silicon raw materials comprises the following steps: 1) Slurry dissolution stage: Add the iron slag washing water solution from the iron removal stage to the high iron silicon raw material to prepare a high iron silicon slurry with a liquid-solid ratio of 2-4:1, and add sulfur dioxide flue gas (containing sulfuric acid, sulfur dioxide, and sodium bisulfite) to dissolve it. The endpoint pH is controlled at 1.5-2.0 to ensure that the leaching rate of cobalt is improved and the formation of iron is inhibited; The chemical composition of the high iron silicon raw material is: moisture 19%~22%, nickel 0.2%~2.14%, cobalt 29%~34%, magnesium 3.6%~8.2%, copper 0.4%~1.2%, manganese 2%~5%, calcium 0.2%~0.8%, iron 0.1%~0.8%, zinc 0.23%~0.8%, aluminum 0.1%, lead 0.001%, silicon 2.5%~6%.

[0005] 2) Raw material pre-iron and silicon removal stage: Sodium carbonate solution is added to the slurry material after the high iron silicon raw material is dissolved, the reaction temperature is controlled to be 80-85°C, the pH during the reaction is 2.0-2.5, and the end point pH is controlled to be 3.0, so that the divalent iron in the solution forms ferrous hydroxide colloid, and the silicon in the solution is removed, so as to achieve the purpose of pre-iron and silicon removal and improve the filtration performance of the solution; 3) Iron removal stage: Sodium sulfite, sodium hypochlorite and sodium carbonate are added to the solution after pre-iron and silicon removal. The initial pH is controlled at 1.5~2, the end pH is controlled at 3~3.5, and the temperature is 80~95℃. After three filter presses and one fine filtration, iron slag and fine filtered liquid are obtained. The iron slag is washed and filtered four times before being discharged. The iron slag washing liquid is returned to the slurry dissolution stage as slurry liquid.

[0006] The liquid after precision filtration contains Co>10g / L, Fe≤0.05g / L, Pb≤0.001g / L; the iron slag contains cobalt ≤0.2%; the iron slag is washed and filtered four times before being discharged.

[0007] 4) Extraction and impurity removal stage: P204 is added to the liquid after precision filtration for extraction, and the extraction ratio is controlled at 1~1.5:1. The pH value before extraction and impurity removal is 2.0~3.5, and the pH value after copper removal is 3.0~4.5. Sodium hydroxide and hydrochloric acid are then added for stripping and saponification to obtain copper manganese chloride solution, ferric chloride solution, soap-post-water phase and liquid after copper removal.

[0008] The copper manganese chloride solution contains cobalt ≤ 0.5g / L, and the solution after copper removal contains Fe ≤ 0.01g / L: the copper manganese chloride solution and the ferric chloride solution are separated, and the post-soap aqueous phase is returned to the extraction and impurity removal stage.

[0009] 5) Nickel-cobalt separation stage: P507 is added to the liquid after copper removal for nickel-cobalt separation, and the oil-liquid ratio is controlled at 3-5:1. The pH value before separation is 3.0-4.5, and the pH value after nickel-cobalt separation is 4.0-5.0. After nickel-cobalt separation, cobalt salt solution, dilute nickel sulfate solution, ferric chloride and soap-containing aqueous phase are obtained.

[0010] The dilute nickel sulfate solution contains cobalt ≤ 0.05 g / L, Fe ≤ 0.02 g / L, and Pb ≤ 0.001 g / L; sodium carbonate is added to the nickel chloride solution to prepare nickel carbonate slag, and the soap-post-water phase returns to the extraction and impurity removal stage.

[0011] 6) Deep impurity removal stage: The cobalt salt solution is subjected to deep impurity removal by resin adsorption. After impurity removal, the content of each element in the liquid is As 0.00005~0.0003g / L, Cd 0.0001~90.00018g / L, Pb 0.00007~0.001g / L, and the oil content is controlled at 1.0~4.5mg / L, thus obtaining a pure new cobalt chloride solution.

[0012] 7) Electrolysis stage: The new cobalt chloride solution is fed into the electrolysis tank for electrolysis to obtain a cobalt plate and an anode solution. The electrolysis current is controlled at 15500A, the cathode solution pH is 0.5-1.0, the cathode solution element content is 60-65g / L Co, 0.0005-0.0003g / L As, and the temperature of the electrolysis tank is controlled at 65-70°C.

[0013] The chlorine gas produced after vacuum evaporation and dechlorination of the anode liquid is absorbed by alkali, and the anode liquid after dechlorination returns to the electrolytic cell.

[0014] The present invention produces, in addition to the cobalt plate, iron slag, nickel carbonate and copper manganese chloride solution.

[0015] In the iron and silicon removal stage, the ferric chloride solution from the iron slag washing water and extraction and impurity removal is mixed with the acid solution to dissolve the raw materials. After stirring, sodium carbonate and sodium hypochlorite solutions are added to make the divalent iron in the solution form ferric hydroxide colloid, and the silicon in the solution is removed, so as to achieve the purpose of pre-iron and silicon removal.

[0016] In the extraction and impurity removal stage and the nickel-cobalt separation stage: sodium hydroxide, hydrochloric acid and P204 are added to the liquid after precision filtration to remove impurities, and the liquid after copper removal is separated from nickel and cobalt by P507 to obtain a cobalt salt solution.

[0017] In summary, this method targets high-iron silicon raw materials, adds appropriate sulfuric acid and extractants, controls the temperature and pH value of each stage, solves the problem that iron and nickel are electrolytically deposited before cobalt during the electrolytic process, resulting in poor quality of cobalt plates, and improves the quality of cobalt plates. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0019] like Figure 1 As shown, a method for producing chloride electrowinning cobalt from high iron silicon raw materials comprises the following steps: 1) Slurry dissolution stage: Add the iron slag washing solution from the iron removal stage to the high iron silicon raw material to prepare a high iron silicon slurry with a liquid-solid ratio of 3:1, and add sulfur dioxide flue gas (containing sulfuric acid, sulfur dioxide, and sodium bisulfite) solution to dissolve it to obtain a leaching solution. The endpoint pH is controlled at 1.5-2.0 to ensure that the leaching rate of cobalt is improved and the formation of iron is inhibited; The chemical composition of high iron silicon raw materials is: water 20.419%, nickel 0.168%, cobalt 26.515%, magnesium 4.427%, copper 0.384%, manganese 4.377%, calcium 0.755%, iron 0.681%, zinc 0.435%, aluminum 0.140%, lead 0.001%, silicon 2.588%; After the high iron silicon raw material is slurried and leached with sulfur dioxide flue gas and iron slag water washing solution, the solution composition is 52.63g / L cobalt, 11.32g / L magnesium, 0.72g / L copper, 14.76g / L manganese, 1.31g / L calcium, 1.82g / L iron, and 1.87g / L zinc.

[0020] 2) Raw material pre-iron and silicon removal stage: the solution from step 1) is mixed with a sodium carbonate solution to form ferrous hydroxide colloid from the divalent iron in the solution, wherein the reaction temperature is 80-85°C, the process pH is 2.0-2.5, and the endpoint pH is controlled at 3.0; 3) Iron removal stage: Sodium sulfite, sodium hypochlorite and sodium carbonate are added to the solution obtained in step 2), the initial pH is controlled at 1.5~2, the end pH is controlled at 3~3.5, the temperature is 80~95°C, and then three filter presses and one precision filtration are performed to obtain iron slag and precision filtered liquid. The iron slag is washed and filtered four times before being discharged, and the iron slag washing liquid is returned to the slurry dissolution stage as a slurry. The cobalt content of the iron slag is ≤0.2%, and the precision filtered liquid contains Co>10g / L, Fe≤0.05g / L, and Pb≤0.001g / L. The cobalt content of the iron slag after sampling for 5 days was 0.059%, 0.16%, 0.12%, 0.16% and 0.14% respectively; 4) Extraction and impurity removal stage: P204 is added to the liquid after precision filtration for extraction and impurity removal. The extraction ratio is controlled at 1~1.5:1. The pH value before extraction and impurity removal is 2.0~3.5, and the pH value after copper removal is 3.0~4.5. The pH value before P204 soap is 1.5~2.0. + 0.72mol / L, H after soap + 0.43mol / L, saponification rate 40.3%, P204 organic 15m 3 / h, liquid 12m 3 / h. Then, sodium hydroxide and hydrochloric acid are added for stripping and saponification to obtain copper manganese chloride solution, ferric chloride solution, soaped water phase and copper-removed liquid.

[0021] The cobalt content of the copper manganese chloride solution is ≤0.5g / L, and the Fe content of the solution after copper removal is ≤0.01g / L; the copper manganese chloride solution and the ferric chloride solution are separated, and the aqueous phase after soap is returned to the extraction and impurity removal stage.

[0022] 5) Nickel-cobalt separation stage: After copper removal, the liquid is separated from nickel and cobalt by P507. The oil-liquid ratio is controlled at 3-5:1. The pH value before separation is 3.0-4.5 and the pH value after separation is 4.0-5.0. P507 organic 33m 3 / h, liquid 8.0m 3 / h, nickel acid washing 1.3m 3 / h, stripping acid 3.5m 3 / h, and then the nickel sulfate solution obtained contained cobalt ≤ 0.05g / L, Fe ≤ 0.02g / L, and Pb ≤ 0.001g / L. The nickel sulfate solution was sampled and stripped for 5 days, and the cobalt content of nickel sulfate was 0.01g / L, 0.0078g / L, 0.022g / L, 0.0039g / L, and 0.01g / L, meeting the requirement that the nickel sulfate solution contained cobalt ≤ 0.05g / L.

[0023] 6) Deep impurity removal stage: In this stage, the cobalt salt solution in stage 5) is subjected to resin adsorption deep impurity removal. The content of each element in the liquid after impurity removal is required to be As 0.00005~0.0003g / L, Cd 0.0001~90.00018g / L, Pb 0.00007~0.001g / L, and the oil content is controlled to 1.0~4.5mg / L to obtain a cobalt chloride solution; 7) Electrowinning stage: The cobalt chloride solution is fed into the electrowinning tank for electrowinning to obtain a cobalt plate and an anode liquid. The electrowinning current is controlled at 15500A. The element content of the cathode liquid is required to be pH 0.5~1.0, contain Co 60~65g / L, and As 0.0005~0.0003g / L. The boric acid content of the cathode liquid is: the highest is 6.98g / L and the lowest is 6.02g / L. The elements in the cobalt plate are As≤0.00025%, Pb≤0.0003%; Cd0.00008%. The tank temperature is controlled at 68~69℃. The highest oil content is 4.6mg / L, the lowest is 1.0mg / L, and the average oil content is 1.72mg / L.

Claims

1. A method for producing chloride electrowinning cobalt from high iron silicon raw materials, characterized in that: The following steps are involved: 1) Slurry dissolution stage: Add the iron slag washing liquid from the iron removal stage to the high iron silicon raw material to prepare the high iron silicon slurry, and add sulfur dioxide flue gas to dissolve it. The endpoint pH is controlled at 1.5~2.0 to ensure the improvement of cobalt leaching rate and inhibit the formation of iron; sulfur dioxide flue gas contains sulfuric acid, sulfur dioxide, and sodium bisulfite; The chemical composition of the high iron silicon raw material is: nickel 0.2%~2.14%, cobalt 29%~34%, magnesium 3.6%~8.2%, copper 0.4%~1.2%, manganese 2%~5%, calcium 0.2%~0.8%, iron 0.1%~0.8%, zinc 0.23%~0.8%, aluminum 0.1%, lead 0.001%, silicon 2.5%~6%; 2) Raw material pre-iron and silicon removal stage: Sodium carbonate solution is added to the slurry material after the high iron silicon raw material is dissolved, the reaction temperature is controlled to be 80-85°C, the pH during the reaction is 2.0-2.5, and the end point pH is controlled to be 3.0, so that the divalent iron in the solution forms ferrous hydroxide colloid, and the silicon in the solution is removed, so as to achieve the purpose of pre-iron and silicon removal; 3) Iron removal stage: Sodium hypochlorite and sodium carbonate are added to the solution after pre-iron and silicon removal, the initial pH is controlled at 1.5-2, the end pH is controlled at 3-3.5, the temperature is 80-95°C, and then three filter presses and one fine filtration are performed to obtain iron slag and fine filtration liquid. The iron slag is washed and filtered four times before being discharged, and the iron slag washing liquid is returned to the slurry dissolution stage as slurry liquid; 4) Extraction and impurity removal stage: P204 is added to the liquid after precision filtration for extraction, and the extraction ratio is controlled to be 1~1.5:

1. The pH value before extraction and impurity removal is 2.0~3.5, and the pH value after copper removal is 3.0~4.

5. Sodium hydroxide and hydrochloric acid are then added for stripping and saponification to obtain copper manganese chloride solution, ferric chloride solution, soap-post aqueous phase and copper-removed liquid; 5) Nickel-cobalt separation stage: P507 is added to the liquid after copper removal for nickel-cobalt separation, and the oil-liquid ratio is controlled at 3-5:

1. The pH value before separation is 3.0-4.5, and the pH value after nickel-cobalt separation is 4.0-5.

0. After nickel-cobalt separation, cobalt salt solution, nickel sulfate solution, ferric chloride and soap-containing aqueous phase are obtained; 6) Deep impurity removal stage: The cobalt salt solution is subjected to deep impurity removal by resin adsorption. The content of each element in the liquid after impurity removal is As0.00005~0.0003g / L, Cd 0.0001~90.00018g / L, Pb 0.00007~0.001g / L, and the oil content is controlled at 1.0~4.5mg / L to obtain a pure cobalt chloride solution; 7) Electrolysis stage: The cobalt chloride solution is fed into the electrolysis tank for electrolysis to obtain cobalt plates and anode liquid. The electrolysis current is controlled to be 15500A, the cathode liquid pH is 0.5~1.0, the cathode liquid element content is 60~65g / L Co, 0.0005~0.0003g / L As, and the temperature of the electrolysis tank is controlled to be 65~70℃.

2. The method for producing chloride electrowinning cobalt from high iron silicon raw materials according to claim 1, characterized in that: In step 1), the liquid-solid ratio of high iron silicon slurry is 2-4:

1.

3. A method for producing chloride electrowinning cobalt from high iron silicon raw materials as claimed in claim 1, characterized in that: In step 3), the liquid after precise filtration contains Co>10g / L, Fe≤0.05g / L, Pb≤0.001g / L; the iron slag contains cobalt ≤0.2%; the iron slag is washed and filtered in four stages before being discharged.

4. A method for producing chloride electrowinning cobalt from high iron silicon raw materials as claimed in claim 1, characterized in that: In step 4), the copper manganese chloride solution contains cobalt ≤ 0.5 g / L, and the solution after copper removal contains Fe ≤ 0.01 g / L: the copper manganese chloride solution and the ferric chloride solution are separated, and the post-soap aqueous phase is returned to the extraction and impurity removal stage.

5. A method for producing chloride electrowinning cobalt from high iron silicon raw materials as claimed in claim 1, characterized in that: In step 5), the nickel sulfate solution contains cobalt ≤ 0.05 g / L, Fe ≤ 0.02 g / L, and Pb ≤ 0.001 g / L; sodium carbonate is added to the nickel chloride solution to prepare nickel carbonate slag, and the soap-post aqueous phase returns to the extraction and impurity removal stage.

6. A method for producing chloride electrowinning cobalt from high iron silicon raw materials as claimed in claim 1, characterized in that: In step 7), the chlorine gas generated after vacuum evaporation and dechlorination of the anolyte is absorbed by alkali, and the anolyte after dechlorination is returned to the electrolytic cell.

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