A method for recycling cobalt, nickel and manganese electrowinning by-products

Abstract

The present invention relates to the field of metallurgical recovery, and in particular to a method for recycling cobalt, nickel, and manganese electrolytic byproducts. The method comprises six steps: co-leaching, leachate separation, oxidative iron removal, solid-liquid separation, deep impurity removal, and finished product preparation. The present invention co-leaches transition metal anode mud and metal particles produced during the electrolytic process, and introduces an iron-containing agent to efficiently and cost-effectively recover electrolytic byproducts. This avoids the addition of reducing agents and the hazards of SO2 and NH3 gas generation during leaching of transition metal anode mud, saves auxiliary material costs, and significantly reduces the safety hazard of H2 generation during metal particle leaching. Furthermore, the present invention utilizes the heat generated by concentrated sulfuric acid dissolving in water without the need for additional heating to achieve the goal of recovering electrolytic byproducts, resulting in economical, environmentally friendly, and safe recovery. This method solves the technical problem of the immature treatment of cobalt, nickel, and manganese electrolytic byproducts in the prior art.

Description

Technical Field

[0001] The present invention relates to the field of metallurgical recovery, and in particular to a method for recycling cobalt, nickel and manganese electrowinning by-products. Background Art

[0002] Oxygen and H are produced at the anode of cobalt electrowinning in sulfuric acid system. + ions, causing the acidity of the electrolyte to become higher and higher, while Co 2+ The concentration of ions decreases due to electrolysis at the cathode. When the acidity is high and Co 2+ When the ion concentration is low, new electrolytic solution needs to be replaced. Cobalt transition metal anode mud is also produced near the anode plate, the main component of which is Co(OH)3. At the edges and corners of the cathode plate, due to the edge effect of the current, there is a large current at the edges and corners of the cathode plate, resulting in rapid deposition of cobalt, forming irregularly shaped cobalt metal particles, the main component of which is metal Co. Similarly, cobalt metal anode mud is produced at the anode of cobalt electrolysis in the hydrochloric acid system, and irregularly shaped cobalt metal particles are produced at the edges and corners of the cathode plate.

[0003] During cobalt electrowinning, the amount of cobalt metal anode mud by-product produced is about 1%-3%. Sulfuric acid + reducing agent leaching is conventionally used, and the amount of reducing agent used is large, resulting in high leaching costs. The commonly used reducing agent is ammonium sulfite, and the leaching process produces waste gases such as SO2 and NH3. At the same time, the amount of irregular cobalt metal particles produced is about 0.5%-2%. Direct leaching with sulfuric acid has an extremely slow leaching speed and continuously produces hydrogen. After the cobalt metal particles are ground and crushed, they are directly leached with sulfuric acid or hydrochloric acid, which speeds up the leaching speed, but still produces hydrogen, and the grinding process consumes a lot of energy. Hydrogen is produced in the above-mentioned process of dissolving the cobalt metal particles with acid, which poses a risk of explosion.

[0004] Similarly, nickel electrowinning also produces nickel transition metal anode mud and nickel metal particles, and manganese electrowinning also produces manganese transition metal anode mud and manganese metal particles. The above-mentioned problems also exist when recycling and processing transition metal anode mud and metal particles. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for recycling cobalt, nickel and manganese electrolytic by-products to solve the technical problem of immature treatment of the above-mentioned electrolytic by-products.

[0006] The present invention provides a method for recycling cobalt, nickel, and manganese electrowinning byproducts. The method is used for recycling any one of the transition metals cobalt, nickel, and manganese electrowinning byproducts, and comprises the following steps:

[0007] Step 1: Co-leaching: In a sulfuric acid system, transition metal anode mud is used as an oxidant, corresponding transition metal particles are used as a reducing agent, electrodeposition residual liquid or dilute sulfuric acid is used as a leaching agent, and an iron-containing agent is added to carry out leaching treatment; in a hydrochloric acid system, transition metal anode mud is used as an oxidant, corresponding transition metal particles are used as a reducing agent, hydrochloric acid is used as a leaching agent, and an iron-containing agent is added to carry out leaching treatment;

[0008] Step 2: Separating the leachate. After the co-leaching is completed, the supernatant is extracted by filtration or standing to obtain the leachate and the remaining transition metal particles. The transition metal particles are returned to step 1 for reuse.

[0009] Step 3: Oxidation to remove iron: add less than 0.1% hydrogen peroxide to the leachate obtained in step 2, and add ammonia or liquid alkali to adjust the pH to 5.5-6.5, so that the Fe content in the filtrate is less than 10 mg / L;

[0010] Step 4: solid-liquid separation to obtain an ammonium-containing filtrate or a sodium-containing filtrate and a filter residue, which is returned to step 1 for repeated use as an iron-containing agent, and the Fe content in the filtrate is less than 10 mg / L;

[0011] Step 5: deep impurity removal: the filtrate obtained in step 4 is subjected to deep impurity removal using an extraction purification line to obtain an ammonium-containing transition metal solution or a sodium-containing transition metal solution;

[0012] Step six, preparing the finished product, the sodium-containing transition metal solution is deoiled by activated carbon and returned to the transition metal electrowinning production line, the by-products produced during the transition metal electrowinning are returned to step one and put into use, and the ammonium-containing transition metal solution is used to prepare products including but not limited to transition metal oxalate products and transition metal carbonate products.

[0013] Preferably, in step one, in the leaching process of the leaching treatment, the liquid-solid mass ratio of dilute acid / transition metal anode mud is 5-15:1, the acid dosage is 1.1-1.2 times the theoretical dosage, the stirring speed is 50r / min-150r / min, the leaching temperature is 20℃-60℃, the leaching time is 2h-5h, and the leaching endpoint pH is 1.5-2.5.

[0014] Preferably, in step 1, the leaching temperature is 30°C-50°C.

[0015] Preferably, in step 1, the added transition metal particles are not ground, and the amount of transition metal used exceeds the theoretical amount, and the weight ratio of transition metal anode mud to corresponding transition metal particles is 1:1-3.

[0016] Preferably, in step 1, the acid is added in multiple portions to maintain the pH at 0.5-1.5.

[0017] Preferably, in step one, an iron-containing agent is added so that the Fe content in the leaching system is 0.5-1.5 g / L. In the sulfuric acid system, the iron-containing agent used is ferrous sulfate or the filter residue obtained in step four, and in the hydrochloric acid system, the iron-containing agent used is ferrous chloride or the filter residue obtained in step four.

[0018] Preferably, in step three, hydrogen peroxide is added to remove iron, and the amount used is 1.5-2 times the theoretical amount, that is, the amount of hydrogen peroxide used, with a purity of 100%, is 45%-60% of the Fe content in the leaching system.

[0019] The method for recycling cobalt, nickel and manganese electrowinning byproducts provided in this solution has the following advantages:

[0020] 1. Transition metal anode mud and corresponding metal particles can be leached simultaneously with a fast leaching speed. The metal leaching rate of transition metal anode mud exceeds 99.5%, which is comparable to conventional technology.

[0021] 2. Compared with leaching transition metal anode mud with sulfuric acid + reducing agent, no additional reducing agent is required;

[0022] 3. Compared with the direct leaching of metal particles after grinding and crushing, there is no need for grinding, the energy consumption is low, the amount of hydrogen generated is greatly reduced, and the addition of excess metal particles can increase the contact area and improve the reaction speed;

[0023] 4. Adding an iron-containing agent can greatly improve the leaching efficiency of step S1. The iron-containing agent can be reused, and most of the Fe can be removed in S3, with almost no Fe entering the filtrate.

[0024] 5. After optimizing the process parameters, step 1 can be carried out at room temperature without the need for additional heating, resulting in low energy consumption;

[0025] 6. Compared with conventional forced air oxidation iron removal, the addition of less than 0.1% hydrogen peroxide can quickly oxidize divalent iron to trivalent iron, generating an iron-containing precipitate. This can be carried out at room temperature, with a high pH adjustment value, which can reduce the Fe content in the filtrate to below 10 mg / L. Although the filter residue may carry cobalt, nickel, and manganese, the filter residue can be reused in step 1 without causing the loss of cobalt, nickel, and manganese. At the same time, the Fe content in the system is low, the amount of hydrogen peroxide used is small, and the cost is low.

[0026] In summary, the leaching, iron removal, solid-liquid separation and other processes of the present invention can be carried out at room temperature, with low energy consumption and low auxiliary material cost, without generating SO2 and NH3 waste gas, and the hydrogen content generated during the collaborative leaching process is less than 10 ppm, thus avoiding the risk of explosion. The present invention has the characteristics of being economical, environmentally friendly and safe. DETAILED DESCRIPTION

[0027] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the technical solutions in the specific implementation methods of the present invention are clearly and completely described below to further illustrate the present invention. Obviously, the specific implementation methods described are only part of the implementation methods of the present invention, rather than all styles.

[0028] Example 1

[0029] The present invention provides a method for recycling cobalt, nickel and manganese electrolytic byproducts, which is used for recycling electrolytic byproducts of transition metals cobalt, nickel and manganese, and comprises the following steps:

[0030] Step 1: Co-leaching: In a sulfuric acid system, transition metal anode mud is used as an oxidant, corresponding transition metal particles are used as a reducing agent, electrodeposition residual liquid or dilute sulfuric acid is used as a leaching agent, and an iron-containing agent is added to carry out leaching treatment; in a hydrochloric acid system, transition metal anode mud is used as an oxidant, corresponding transition metal particles are used as a reducing agent, hydrochloric acid is used as a leaching agent, and an iron-containing agent is added to carry out leaching treatment;

[0031] Step 2: Separating the leachate. After the co-leaching is completed, the supernatant is extracted by filtration or standing to obtain the leachate and the remaining transition metal particles. The transition metal particles are returned to step 1 for reuse.

[0032] Step 3: Oxidation to remove iron: add less than 0.1% hydrogen peroxide to the leachate obtained in step 2, and add ammonia or liquid alkali to adjust the pH to 5.5-6.5, so that the Fe content in the filtrate is less than 10 mg / L;

[0033] Step 4: solid-liquid separation to obtain an ammonium-containing filtrate or a sodium-containing filtrate and a filter residue, which is returned to step 1 for repeated use as an iron-containing agent, and the Fe content in the filtrate is less than 10 mg / L;

[0034] Step 5: deep impurity removal: the filtrate obtained in step 4 is subjected to deep impurity removal using an extraction purification line to obtain an ammonium-containing transition metal solution or a sodium-containing transition metal solution;

[0035] Step six, preparing the finished product, the sodium-containing transition metal solution is deoiled by activated carbon and returned to the electrolytic production line, the by-products produced during the transition metal electrolytic deposition are returned to step one and put into use, and the ammonium-containing transition metal solution is used to prepare products including but not limited to transition metal oxalate products and transition metal carbonate products.

[0036] In step 1, when any transition metal anode mud of cobalt, nickel, or manganese is used, the same metal must be used as the corresponding transition metal particles. For example, if the transition metal anode mud is cobalt anode mud, the corresponding transition metal particles used must be cobalt metal particles.

[0037] In step one, in the leaching process of the leaching treatment, the liquid-solid mass ratio of dilute acid / transition metal anode mud is 5-15:1, the acid dosage is 1.1-1.2 times the theoretical dosage, the stirring speed is 50r / min-150r / min, the leaching temperature is 20℃-60℃, and the leaching temperature is controlled as much as possible to be 30℃-50℃, the leaching time is 2h-5h, and the leaching endpoint pH is 1.5-2.5.

[0038] In step 1, the added transition metal particles are not ground, and the amount of transition metal used exceeds the theoretical amount, with the weight ratio of transition metal anode mud to transition metal particles being 1:1-3.

[0039] In step 1, acid is added in several portions to maintain the pH at 0.5-1.5.

[0040] In step one, an iron-containing agent is added to make the Fe content in the leaching system 0.5-1.5 g / L. In the sulfuric acid system, the iron-containing agent used is ferrous sulfate or the filter residue obtained in step four. In the hydrochloric acid system, the iron-containing agent used is ferrous chloride or the filter residue obtained in step four.

[0041] In step 3, hydrogen peroxide is added to remove iron. The amount used is 1.5-2 times the theoretical amount, that is, the amount of hydrogen peroxide used, with a purity of 100%, is 45%-60% of the Fe content in the leaching system. The theoretical amount of hydrogen peroxide is based on the reaction equation 2Fe 2+ +H2O2=2Fe 3+ +2OH - , calculated amount of hydrogen peroxide used.

[0042] The present invention provides a method for recycling cobalt, nickel, and manganese electrowinning byproducts. When recycling cobalt electrowinning byproducts, in step 1, the following reactions mainly occur:

[0043] Co(OH)3+Fe 2＋ +3H ＋ =Co 2＋ +Fe 3＋ +3H2O

[0044] 2Fe 3＋ +Co=Co 2＋ +2Fe 2＋

[0045] The above two formulas are combined into

[0046] 2Co(OH)3+Co+6H ＋ =3Co 2＋ +6H2O

[0047] That is, 2Co(OH)3+Co+3H2SO4=3CoSO4+6H2O. The theoretical amount of H2SO4 can be calculated based on this reaction equation.

[0048] It should be noted that nickel and manganese, as transition metals, have multiple valence states, and high-valence oxide anode mud and zero-valence metal particles are also produced during the electrolytic deposition process. In the co-leaching process of step one, a chemical reaction similar to that in the co-leaching process of drilling electrolytic deposition by-products occurs, so the principles and processes are exactly the same.

[0049] The present invention provides a method for recycling cobalt, nickel, and manganese electrowinning byproducts. In step three, the following reactions mainly occur:

[0050] 2Fe 2+ +H2O2=2Fe 3+ +2OH - .

[0051] According to the present invention, a method for recycling cobalt, nickel, and manganese electrowinning byproducts was developed by adjusting process parameters to produce the following seven experimental groups. Experimental Group 5 used electrowinning residual liquid instead of sulfuric acid, with the amount of the residual liquid calculated based on the sulfuric acid content. Experimental Group 6 did not add an iron-containing agent. Experimental Group 7 was used to treat manganese electrowinning byproducts. The process parameters and implementation results of Experimental Groups 1-7 are shown in Table 1.

[0052] Table 1 Process parameters and process effects of experimental groups 1-7

[0053]

[0054] Note: The leaching rate refers to the leaching rate of transition metal anode mud. The leaching rate of metal particles is not taken into account. Undissolved metal particles can be used for the next leaching. After multiple leaching, the leaching rate of metal particles can be close to 100%.

[0055] Comparative Example 2

[0056] On the basis of Example 1, according to the method for recycling cobalt, nickel and manganese electrowinning byproducts of the present invention, the process parameters were adjusted to prepare the following three groups of experimental groups 8-10 for comparison.

[0057] Experimental Group 8, in which cobalt anode slime was leached with sulfuric acid alone, was compared to the method for recovering cobalt, nickel, and manganese electrowinning byproducts described in Example 1. In contrast, no cobalt metal particles or iron-containing agent were added. Instead, ammonium sulfite was added as a reducing agent at a dosage of 1 t / tCo. The leaching time was 3 h, generating waste gases such as SO2 and NH3.

[0058] Experimental Group 9, using sulfuric acid alone to leach uncrushed cobalt metal particles, compared to the method for recovering cobalt, nickel, and manganese electrowinning byproducts described in Example 1, omitted the addition of cobalt metal anode mud and iron-containing agents. The leaching temperature was 80°C, and hydrogen was continuously generated. Although the hydrogen concentration was below 25 ppm, the leaching rate was too slow. After 10 hours of leaching, the leaching yield was only 6.67%, making it unsuitable for mass production.

[0059] In experimental group 10, compared with comparative experimental group 9, the cobalt metal particles were crushed into metal powders of less than 60 mesh, the leaching temperature was 30°C, the leaching time was 10 hours, and hydrogen was continuously generated, with its concentration reaching a maximum of 150ppm, posing an explosion risk. Although the leaching rate was significantly increased compared with comparative experimental group 9, the leaching rate was only 38.67%.

[0060] The process parameters and implementation effects of experimental groups 8-10 are shown in Table 2.

[0061] Table 2 Comparative experimental group 8-10 process parameters and process effects

[0062]

[0063] It can be seen from experimental groups 1-5 that the hydrogen content generated during the synergistic leaching process of the present invention is lower than 10 ppm, which is significantly away from the hydrogen explosion limit of 4%-75.6%. Compared with experimental group 10, the hydrogen concentration is reduced by more than 90%.

[0064] Comparing experimental group 1 with experimental group 6, when no Fe was added in step 1, the cobalt leaching rate was only 27.42%, which was much lower than the leaching rate of 99.68% when Fe was added.

[0065] Experimental Groups 8 and 10 produced relatively high concentrations of SO2, NH3, and H2, causing environmental pollution. Experimental Group 10 continuously produced relatively high concentrations of H2, posing a risk of explosion. Experimental Group 8 also required the addition of a large amount of ammonium sulfite as a reducing agent, which was costly.

[0066] In experimental groups 9 and 10, the leaching rate of cobalt metal particles directly leached with sulfuric acid was slow regardless of whether they were crushed or not. Compared with experimental groups 1-5, the leaching rate was much lower under the conditions of longer leaching time (from 2-5h to 10h) and higher leaching temperature (from 20-60℃ to 80℃).

[0067] The process parameters and results of Experimental Groups 1-5 and 7 indicate that the technology of the present invention synergistically leaches transition metal anode mud and metal particles produced by the electrolysis of cobalt, nickel, and manganese, and introduces an iron-containing agent to efficiently and cost-effectively recover electrolysis by-products. This avoids the addition of reducing agents and the hazards of SO2 and NH3 gas generation during leaching of transition metal anode mud, saves on auxiliary material costs, and significantly reduces the safety hazard of H2 generation during the leaching of metal particles. Furthermore, the technology of the present invention utilizes the heat generated by the dissolution of concentrated sulfuric acid in water without the need for additional heating to achieve the goal of recovering electrolysis by-products.

[0068] Obviously, the above embodiment is only an example for clear explanation and is not limited to this example. Different forms of changes made in this field are not listed here, so the derived changes are all within the scope of protection of the present invention.

Claims

1. A method for recycling cobalt, nickel and manganese electrowinning byproducts, wherein the method is used for recycling transition metal electrowinning byproducts, wherein the processed transition metal is any one of cobalt, nickel and manganese, and wherein: The recycling method includes the following steps: Step 1: Co-leaching: In a sulfuric acid system, transition metal anode mud is used as an oxidant, corresponding transition metal particles are used as a reducing agent, electrodeposition residual liquid or dilute sulfuric acid is used as a leaching agent, and an iron-containing agent is added to carry out leaching treatment; in a hydrochloric acid system, transition metal anode mud is used as an oxidant, corresponding transition metal particles are used as a reducing agent, hydrochloric acid is used as a leaching agent, and an iron-containing agent is added to carry out leaching treatment; Step 2: Separating the leachate. After the co-leaching is completed, the supernatant is extracted by filtration or standing to obtain the leachate and the remaining transition metal particles. The transition metal particles are returned to step 1 for reuse. Step 3: Oxidation for iron removal: add less than 0.1% hydrogen peroxide to the leachate obtained in step 2, add ammonia or liquid alkali, adjust the pH to 5.5-6.5, and make the Fe content in the filtrate less than 10 mg / L; Step 4: solid-liquid separation to obtain an ammonium-containing filtrate or a sodium-containing filtrate and a filter residue, which is returned to step 1 for repeated use as an iron-containing agent, and the Fe content in the filtrate is less than 10 mg / L; Step 5: deep impurity removal: the filtrate obtained in step 4 is subjected to deep impurity removal using an extraction purification line to obtain an ammonium-containing transition metal solution or a sodium-containing transition metal solution; Step six, preparing the finished product, the sodium-containing transition metal solution is deoiled by activated carbon and returned to the transition metal electrowinning production line, the by-products produced during the transition metal electrowinning are returned to step one and put into use, and the ammonium-containing transition metal solution is used to prepare products including but not limited to transition metal oxalate products and transition metal carbonate products.

2. The method for recycling cobalt, nickel and manganese electrowinning byproducts according to claim 1, wherein: In step one, in the leaching process of the leaching treatment, the liquid-solid mass ratio of dilute acid / transition metal anode mud is 5-15:1, the acid dosage is 1.1-1.2 times the theoretical dosage, the stirring speed is 50r / min-150r / min, the leaching temperature is 20℃-60℃, the leaching time is 2h-5h, and the leaching endpoint pH is 1.5-2.

5.

3. The method for recycling cobalt, nickel and manganese electrowinning byproducts according to claim 2, wherein: In step 1, the leaching temperature is 30°C-50°C.

4. The method for recycling cobalt, nickel and manganese electrowinning byproducts according to claim 1, wherein: In step 1, the added corresponding transition metal particles are not ground, and the amount of transition metal used exceeds the theoretical amount, with the weight ratio of transition metal anode mud to corresponding transition metal particles being 1:1-3.

5. The method for recycling cobalt, nickel and manganese electrowinning byproducts according to claim 1, wherein: In step 1, acid is added in several portions to maintain the pH at 0.5-1.

5.

6. The method for recycling cobalt, nickel and manganese electrowinning byproducts according to claim 1, characterized in that: In step one, an iron-containing agent is added to make the Fe content in the leaching system 0.5-1.5 g / L. In the sulfuric acid system, the iron-containing agent used is ferrous sulfate or the filter residue obtained in step four. In the hydrochloric acid system, the iron-containing agent used is ferrous chloride or the filter residue obtained in step four.

7. The method for recycling cobalt, nickel and manganese electrowinning byproducts according to claim 1, characterized in that: In step three, hydrogen peroxide is added to remove iron, and the amount used is 1.5-2 times the theoretical amount.

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