Method for separating nickel and cobalt elements from anode product

Abstract

The invention relates to the technical field of lithium battery material recovery, in particular to a method for separating nickel and cobalt elements from an anode product, and the method specifically comprises the following steps: carrying out acid pickling treatment on a manganese dioxide crude product in the anode product to obtain acid pickling residues; then adding an ammonia leaching agent and a reducing agent into the pickling residues for ammonia leaching treatment, and carrying out solid-liquid separation to obtain a manganese dioxide product; the ammonia leaching agent comprises ammonium sulfate and ammonia water; wherein the total ammonia concentration in the ammonia leaching agent is 80-230 g / L; the total ammonia concentration is the sum of the NH3 concentration and the NH4 < + > concentration. Through acid pickling treatment and ammonia leaching treatment, efficient separation of manganese dioxide and nickel and cobalt elements in the anode product is achieved, and the manganese dioxide product with high purity and high yield is obtained.

Description

Technical Field

[0001] The present application relates to the technical field of lithium battery material recovery, and in particular to a method for separating nickel and cobalt elements from anode products. Background Art

[0002] Nickel-cobalt-manganese ternary lithium batteries have achieved great success in the fields of 3C digital, new energy vehicles and chemical energy storage due to their excellent rate performance, high safety and high specific capacity. However, the average service life of lithium batteries is about 6 to 8 years, so a large number of retired batteries will be generated. It is reported that the amount of retired batteries will reach 437GWh in 2030, of which 43,200 tons of recyclable lithium equivalent, 1.312 million tons of nickel equivalent, 102,700 tons of cobalt equivalent and 127,400 tons of manganese equivalent can be recovered.

[0003] The traditional recycling methods of nickel-cobalt-manganese ternary positive electrode materials are mainly pyrolysis and wet processing, and some literature also introduces bioleaching methods. However, the equipment and process costs of pyrolysis are high, the energy consumption is large, and the economic benefits are not significant. The wet method requires the use of a large amount of organic solvents for extraction, which brings environmental pollution risks. The bioleaching method is still in the laboratory verification stage and the leaching takes a long time, making it difficult to industrialize. The current cutting-edge nickel-cobalt-manganese ternary lithium battery recycling method uses acid + reducing agent to dissolve the ternary positive electrode material, recover nickel and cobalt metals at the cathode by electrolysis, recover manganese elements at the anode in the form of manganese dioxide, and recover lithium elements in the solution in the form of lithium salts. However, a small amount of cobalt tetraoxide and nickel trioxide are doped in the anode product manganese dioxide. The doped product reduces the purity of manganese dioxide on the one hand and the yield of nickel and cobalt metal on the other. The dissolution and washing of cobalt tetraoxide and nickel trioxide in the acid + reducing agent acid dissolution method faces the problems of simultaneous dissolution of manganese dioxide and low efficiency of nickel and cobalt separation. Therefore, it is an urgent problem to find an efficient process for separating a small amount of cobalt tetroxide and nickel trioxide doped in the anode product manganese dioxide. Summary of the invention

[0004] In view of this, the present application provides a method for separating nickel and cobalt elements from anode products, which, combined with acid washing and double-stage ammonia leaching processes, can deeply separate nickel and cobalt elements in the anode product manganese dioxide to obtain high-purity manganese dioxide, which has the advantages of high efficiency, solvent recycling, economy and environmental protection.

[0005] The method for separating nickel and cobalt elements from an anode product provided by the present application comprises the following steps: step S1, obtaining a crude manganese dioxide product, wherein the crude manganese dioxide product contains impurities of cobalt tetraoxide and nickel trioxide, wherein the crude manganese dioxide product comes from the anode product; step S2, subjecting the crude manganese dioxide product to an acid wash treatment to remove nickel trioxide therein, thereby obtaining an acid wash residue; step S3, adding an ammonia leaching agent and a reducing agent to the acid wash residue for an ammonia leaching treatment to remove cobalt tetraoxide therein, and then performing solid-liquid separation to obtain a manganese dioxide product; wherein the ammonia leaching agent comprises ammonium sulfate and ammonia water, and the total ammonia concentration in the ammonia leaching agent is 80 to 230 g / L; the total ammonia concentration is the concentration of NH3 and NH4 + The sum of the concentrations. For the crude manganese dioxide obtained by electrolysis, the present application adopts pickling treatment to recover the residual nickel element, and then performs ammonia leaching treatment on the pickling slag to recover the residual cobalt element. By controlling the total ammonia concentration in the ammonia leaching agent, the ammonia leaching agent and the reducing agent are closely matched to convert the cobalt element into a complex solution, thereby achieving efficient separation of manganese dioxide and nickel and cobalt elements, obtaining high-purity and high-yield manganese dioxide products and nickel-cobalt alloys, which is beneficial to the recycling of resources and improving the added value of products.

[0006] In the present application, the anode product is pretreated to obtain crude manganese dioxide, and the pretreatment includes washing, high-temperature drying, etc.

[0007] In some embodiments, NH4 + The molar ratio of NH3 in ammonia water is 1:(1-3). Ammonium sulfate and ammonia water are used as ammonia leaching agent, wherein NH3 in ammonia water can form complex ions with divalent cobalt ions in manganese dioxide and exist in the form of solution to achieve the separation of cobalt element and manganese dioxide crude product. This application regulates the NH4 + The molar ratio of NH3 to ammonia water is within the above range, which can better promote the coordination of the two, increase the leaching rate of cobalt elements, and is beneficial to further improve the purity of manganese dioxide products.

[0008] In some embodiments, the reducing agent includes at least one of hydrogen peroxide, hydrazine hydrate, or hydroxylamine.

[0009] In some embodiments, the ammonia leaching treatment includes: adding an ammonia leaching agent and a reducing agent to the pickling slag for a first-stage ammonia leaching treatment, solid-liquid separation, and obtaining a first-stage leaching solution and a first-stage manganese dioxide; then adding an ammonia leaching agent and a reducing agent to the first-stage manganese dioxide for a second-stage ammonia leaching treatment, solid-liquid separation, and obtaining a second-stage leaching solution and a second-stage manganese dioxide; washing the second-stage manganese dioxide to obtain a manganese dioxide product. The present application adopts a double-stage ammonia leaching treatment, which can deeply leach the cobalt element in the pickling slag, which is conducive to further improving the purity of the manganese dioxide product and improving the yield of the cobalt element.

[0010] In some embodiments, the conditions of the first ammonia immersion treatment and the second ammonia immersion treatment include: ammonia immersion pressure: 0.5-1 MPa; ammonia immersion temperature: 60-70°C; ammonia immersion time: 3-5 hours; wherein the conditions of the first ammonia immersion treatment are the same as the conditions of the second ammonia immersion treatment, or the conditions of the first ammonia immersion treatment are different from the conditions of the second ammonia immersion treatment.

[0011] In some embodiments, during the first ammonia leaching process, the volume ratio of the mass of the pickling slag to the ammonia leaching agent is 100g:400-500ml; during the second ammonia leaching process, the volume ratio of the mass of the first manganese dioxide to the ammonia leaching agent is 100g:160-250ml.

[0012] In some embodiments, during the first ammonia leaching process, the molar ratio of cobalt oxide to reducing agent in the pickling slag is 1:(1-10); during the second ammonia leaching process, the molar ratio of cobalt oxide to reducing agent in the first manganese dioxide is 1:(1-10); wherein the molar amount of the reducing agent is based on the molar amount of the reducing substance.

[0013] In some embodiments, the method further comprises step S4: a. subjecting the first-stage leachate and / or the second-stage leachate to a first-stage evaporation crystallization treatment to obtain crystal a, ammonia, water vapor and concentrated solution, wherein crystal a contains ammonium sulfate and the concentrated solution contains cobalt-ammonia complex, manganese sulfate and ammonium sulfate; b. subjecting the concentrated solution to a second-stage evaporation crystallization treatment to obtain crystal b, wherein crystal b comprises ammonium sulfate, cobalt sulfate and manganese sulfate; c. subjecting crystal b to a roasting treatment under an inert gas to obtain ammonia, sulfur dioxide and a solid mixture, wherein the solid mixture comprises cobalt sulfate and manganese sulfate. In this process, the first-stage leachate is first subjected to high-temperature crystallization, so that more ammonium sulfate can be precipitated first, and the precipitated ammonium sulfate is mixed with the evaporated ammonia and water vapor to prepare the ammonia leaching agent again, thereby improving the recovery rate of the ammonia leaching agent and enabling the ammonia leaching agent to be effectively recycled. After that, the cobalt-ammonia complex, manganese sulfate and ammonium sulfate remaining in the concentrated solution are further evaporated and crystallized. The cobalt-ammonia complex is decomposed at high temperature to obtain cobalt sulfate and ammonia gas, and cobalt is converted into the corresponding sulfate, which provides the possibility for the subsequent electrolytic extraction of Co element. Then, by roasting, the ammonium sulfate is separated from the cobalt sulfate and manganese sulfate to obtain cobalt and manganese sulfates, and electrolysis can be continued to recover the Co element and the Mn element. In this process. The secondary evaporation and crystallization treatment of the first-stage leaching solution is combined with roasting, which not only recycles the ammonia leaching solution, but also improves the recovery rate of the Co element and the Mn element.

[0014] In some embodiments, the conditions for the first stage evaporation crystallization treatment include: evaporation temperature of 105-120°C; the cut-off condition is: the mass content of cobalt element in the concentrated solution is 60-100 g / L; and / or, the conditions for the second stage evaporation crystallization treatment include: evaporation temperature of 180-280°C, and evaporation time of 2-5 hours.

[0015] In some embodiments, the crystal a, ammonia gas and water vapor obtained in step a are prepared as an ammonia infusion for use.

[0016] In some embodiments, the ammonia gas and sulfur dioxide obtained in step c are converted back into ammonium sulfate through reaction as an ingredient of the ammonia leaching agent.

[0017] In some embodiments, in step c, the calcination temperature of the calcination treatment is 350-550° C., the heating rate is 5-15° C. / min, and the calcination time is 0.5-3 h; and / or the inert gas is selected from at least one of nitrogen or argon.

[0018] In some embodiments, the method further comprises: combining the second-stage leaching solution with an ammonia leaching agent. The second-stage leaching solution can be subjected to an evaporation crystallization treatment, or can also be combined with an ammonia leaching agent.

[0019] In some embodiments, in step S1, the method for obtaining the anode product includes: mixing the waste nickel-cobalt-manganese ternary positive electrode material, acid solution and reducing agent for acid leaching to obtain an acid leaching solution, and electrolyzing the acid leaching solution to obtain the anode product; adding the solid mixture obtained in step c to the acid leaching solution for electrolysis. The solid mixture of cobalt sulfate and manganese sulfate obtained in step c is added to the acid leaching solution for continued electrolysis, thereby improving the recovery rate of Co and Mn elements.

[0020] In the present application, the nickel-cobalt-manganese ternary positive electrode material can be obtained by methods known in the art, such as disassembling the nickel-cobalt-manganese ternary lithium-ion battery and obtaining the waste nickel-cobalt-manganese ternary positive electrode material from the positive electrode sheet.

[0021] In some embodiments, the acid leaching treatment can be performed by methods known in the art, as long as the purpose of the present application can be achieved. For example, the nickel-cobalt-manganese ternary positive electrode material can be acid-leached using sulfuric acid and hydrogen peroxide.

[0022] In some embodiments, the pH value during electrolysis is controlled to be 3-6, and the current density is controlled to be 0.5-3 mA / cm 2 During the electrolytic treatment, crude manganese dioxide is obtained at the anode and a nickel-cobalt metal alloy is obtained at the cathode.

[0023] In some embodiments, in step S2, the acid used in the pickling treatment is sulfuric acid; the molar concentration of the sulfuric acid is 0.5 to 1.5 mol / L.

[0024] In some embodiments, the mass ratio of crude manganese dioxide to sulfuric acid is 100 g: 400-500 ml.

[0025] In some embodiments, in step S2, a pickling solution is also obtained, and the pickling solution contains nickel sulfate. The pickling solution is added to the acid leaching solution for electrolytic treatment to improve the recovery rate of the Ni element.

[0026] Based on the method for separating nickel and cobalt elements from anode products provided in the present application, the beneficial effects are at least:

[0027] The present application separates the residual nickel element from the crude manganese dioxide in the anode product by pickling, and then performs ammonia leaching on the pickling residue. By controlling the total ammonia concentration in the ammonia leaching agent, the ammonia leaching agent and the reducing agent are closely coordinated to separate the cobalt element, thereby achieving efficient separation of manganese dioxide and nickel and cobalt elements, and obtaining a manganese dioxide product with high purity and high yield.

[0028] The ammoniacal leaching solution containing cobalt, manganese and the like is subjected to a first-stage evaporation and crystallization treatment to separate ammonium sulfate crystals, ammonia gas and water vapor, which can be recycled as raw materials of the ammoniacal leaching agent. The obtained concentrated solution is further subjected to a second-stage evaporation and crystallization treatment to further decompose the cobalt-ammonia complex to obtain cobalt sulfate. The solid mixture containing cobalt sulfate and manganese sulfate is returned to the electrolysis process to continue to extract Co and Mn elements, wherein the Co element is converted into a cobalt alloy and the Mn element is converted into manganese dioxide, thereby realizing the recycling of materials, improving the recovery rates of the Co and Mn elements, and having the advantages of simple process and cost saving.

[0029] The pickling solution containing nickel sulfate can also be returned to the electrolysis process to continue extracting the Ni element. The nickel-cobalt alloy obtained at the cathode during the electrolysis process can achieve a high yield and purity.

[0030] In this process, the Ni element and the Co element are removed step by step, that is, nickel trioxide is first removed by using a low concentration of acid, and then cobalt tetroxide is removed by using an ammonia leaching agent, thereby improving the impurity removal rate and obtaining MnO2 with higher purity. The obtained cobalt and manganese sulfates can also be returned to the electrolysis process to continue to extract Co and Mn elements, and the ammonia leaching solution can also be efficiently recovered, solving the problem of difficulty in separating a small amount of nickel and cobalt in the anode product manganese dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A process flow chart of a method for separating nickel and cobalt elements from anode products provided in Example 1 of the present application. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present application more clear, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

[0033] In the process of recycling nickel-cobalt-manganese ternary positive electrode materials, the anode product obtained by electrolysis often contains some impurities of Ni and Co, which makes the purity of the anode product MnO2 low and affects the recovery rate of Ni and Co elements. The methods in the prior art often cannot effectively separate the Ni and Co elements in the anode product MnO2, and since the acid and alkali used in the process cannot be effectively recovered, a large amount of acid and alkali is consumed, and the entire process flow is relatively complicated.

[0034] In view of this, the present application provides a method for efficiently separating nickel and cobalt elements from an anode product, comprising the following steps: step S1, obtaining a crude manganese dioxide product, wherein the crude manganese dioxide product contains cobalt tetroxide and nickel trioxide, wherein the crude manganese dioxide product comes from the anode product; step S2, subjecting the crude manganese dioxide product to an acid wash treatment to remove nickel trioxide therein, thereby obtaining an acid wash residue; step S3, adding an ammonia leaching agent and a reducing agent to the acid wash residue for an ammonia leaching treatment to remove cobalt tetroxide therein, and then performing solid-liquid separation to obtain a manganese dioxide product; wherein the ammonia leaching agent comprises ammonium sulfate and ammonia water; the total ammonia concentration in the ammonia leaching agent is 80 to 230 g / L; the total ammonia concentration is NH3 concentration and NH4 + The sum of concentrations. The present application uses pickling treatment to recover the residual nickel element in the crude manganese dioxide, realizes the efficient separation of manganese dioxide and nickel elements, and then performs ammonia leaching on the pickling residue, and controls the total ammonia concentration in the ammonia leaching agent so that the ammonia leaching agent and the reducing agent are closely matched to convert the cobalt element into a complex solution, and then performs solid-liquid separation to realize the efficient separation of manganese dioxide and cobalt elements, and obtains a manganese dioxide product with high purity and high yield. In addition, the pickling solution containing nickel elements and the leaching solution containing cobalt elements and manganese elements can be treated by electrolysis to obtain nickel-cobalt alloy and manganese dioxide, thereby improving the yield of nickel, cobalt and manganese.

[0035] In the present application, the crude manganese dioxide is derived from the anode product, including method 1: the anode product is subjected to treatments including but not limited to cleaning, drying, screening, etc. to obtain the crude manganese dioxide; or method 2: the anode product can be directly used as the crude manganese dioxide for subsequent treatment.

[0036] In some embodiments, in step S2, the acid used for the pickling treatment is sulfuric acid; the molar concentration of sulfuric acid is 0.5-1.5 mol / L, for example, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L or a value within the range composed of any two of them.

[0037] In some embodiments, the ratio of the mass of the crude manganese dioxide to the volume of sulfuric acid is 100 g: 400-500 ml. For example, when the mass of the crude manganese dioxide is 100 g, the volume of sulfuric acid used is 400 ml, 410 ml, 420 ml, 430 ml, 440 ml, 450 ml, 460 ml, 470 ml, 480 ml, 490 ml, 500 ml, or a value within the range of any two thereof.

[0038] The present application can remove nickel trioxide through the above-mentioned pickling treatment, using sulfuric acid and controlling the molar concentration to meet the above-mentioned range, and converting nickel trioxide into nickel sulfate and washing it out under relatively low sulfuric acid concentration conditions, while cobalt tetraoxide and manganese dioxide contained in the crude manganese dioxide need to react with sulfuric acid under the condition of the participation of a reducing agent (such as hydrogen peroxide), so pickling can separate cobalt and nickel elements. The use of pickling treatment for pre-nickel removal can prevent the nickel element from forming a nickel sulfate ammonia complex during subsequent ammonia leaching. The complex has strong stability, and it is difficult to separate the nickel element from the nickel sulfate ammonia complex by high-temperature roasting. After the pickling treatment is completed, a pickling solution and a pickling slag are obtained, wherein the pickling solution can be returned to the above-mentioned electrolytic treatment to convert the nickel element into a nickel-cobalt alloy.

[0039] In the present application, the reaction equation of sulfuric acid and nickel trioxide in the pickling treatment is shown in Formula 1:

[0040] 2Ni2O3+4H2SO4→4NiSO4+O2+4H2O Formula 1.

[0041] The reaction equation of cobalt tetraoxide reacting with sulfuric acid in the presence of hydrogen peroxide is shown in Formula 2:

[0042] 3H2SO4+H2O2+Co3O4=3CoSO4+4H2O+O2 Formula 2.

[0043] The present application also includes: before the ammonia leaching treatment, the pickling residue is washed to a pH of 6.5-7, the washing can be carried out with deionized water, and after washing, a drying treatment can be carried out, such as drying.

[0044] In the present application, the total ammonia concentration in the ammonia leaching agent is 80 to 230 g / L, for example, the total ammonia concentration is 80 g / L, 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L, 160 g / L, 170 g / L, 180 g / L, 190 g / L, 200 g / L, 210 g / L, 230 g / L or a value within the range composed of any two of them. The present application regulates the total ammonia concentration of the ammonia leaching agent to meet the above range, which can ensure an excellent leaching effect on the cobalt element in the pickling slag, improve the purity and yield of the manganese dioxide product, and improve the yield of the nickel-cobalt alloy.

[0045] In some embodiments, NH4 + The molar ratio of NH4 in ammonium sulfate is 1:(1-3). + The molar ratio of NH3 in ammonia water is 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2.3, 1:2.6, 1:2.8, 1:3 or a value within the range of any two of these numerical ratios. Ammonium sulfate and ammonia water are used as an ammonia soaking agent, wherein NH3 in ammonia water can form complex ions with divalent cobalt ions in manganese dioxide and exist in the form of a solution to achieve separation of cobalt elements and crude manganese dioxide. This application regulates the concentration of NH4 in ammonium sulfate in the ammonia soaking agent. + The molar ratio of NH3 to ammonia water is within the above range, which can better promote the coordination between the two, improve the leaching rate of cobalt element, and is beneficial to further improve the purity of manganese dioxide product and increase the yield of nickel-cobalt alloy.

[0046] In some embodiments, the reducing agent includes at least one of hydrogen peroxide, hydrazine hydrate or hydroxylamine. The use of these reducing agents can better reduce cobalt tetraoxide in the crude manganese dioxide to divalent cobalt ions, thereby forming complex ions with NH3, improving the efficiency of ammonia leaching, and will not introduce additional cationic impurities, which is conducive to improving the purity of products and intermediates.

[0047] In some more preferred embodiments, the ammonia leaching treatment includes: adding an ammonia leaching agent and a reducing agent to the pickling slag for a first-stage ammonia leaching treatment, separating the solid and the liquid to obtain a first-stage leaching solution and a first-stage manganese dioxide; then adding an ammonia leaching agent and a reducing agent to the first-stage manganese dioxide for a second-stage ammonia leaching treatment, separating the solid and the liquid to obtain a second-stage leaching solution and a second-stage manganese dioxide; washing the second-stage manganese dioxide to obtain a manganese dioxide product. The present application adopts a two-stage ammonia leaching treatment, in which the cobalt element in the first-stage leaching solution is hexaammine cobalt sulfate (Co(NH3)6SO4, in which the hexaammine cobalt ion is Co(NH3)6 2+ ) and a small amount of manganese in the form of Mn 2+ The first stage manganese dioxide is subjected to ammonia leaching for two stages, which can further deeply leach out cobalt ions and improve the purity of the manganese dioxide product.

[0048] In some embodiments, the conditions of the first ammonia immersion treatment and the second ammonia immersion treatment include: ammonia immersion pressure: 0.5-1 MPa; ammonia immersion temperature: 60-70°C; ammonia immersion time: 3-5 hours; wherein the conditions of the first ammonia immersion treatment are the same as the conditions of the second ammonia immersion treatment, or the conditions of the first ammonia immersion treatment are different from the conditions of the second ammonia immersion treatment.

[0049] In some exemplary embodiments, the ammonia immersion pressure is 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, 1MPa or a value within the range of any two thereof, the ammonia immersion temperature is 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C or a value within the range of any two thereof, and the ammonia immersion time is 3h, 3.2h, 3.7h, 4.1h, 4.5h, 4.8h, 5h or a value within the range of any two thereof. When the first-stage ammonia immersion treatment and the second-stage ammonia immersion treatment are controlled to meet the above conditions, the leaching efficiency and leaching degree of the ammonia immersion agent for the cobalt element can be improved, and the purity of the manganese dioxide product can be further improved.

[0050] In some embodiments, during the first ammonia leaching process, the volume ratio of the mass of the pickling slag to the ammonia leaching agent is 100g:400-500ml. For example, when the mass of the pickling slag is 100g, the volume of the corresponding ammonia leaching agent is 400ml, 410ml, 420ml, 430ml, 440ml, 450ml, 460ml, 470ml, 480ml, 490ml, 500ml or a value within the range composed of any two of them.

[0051] In some embodiments, during the two-stage ammonia leaching process, the volume ratio of the mass of the first stage manganese dioxide to the ammonia leaching agent is 100g:160-250ml. For example, when the mass of the first stage manganese dioxide is 100g, the volume of the corresponding ammonia leaching agent is 160ml, 170ml, 180ml, 190ml, 200ml, 210ml, 220ml, 230ml, 240ml, 250ml or a value within the range composed of any two of them.

[0052] In some embodiments, during the first ammonia leaching process, the molar ratio of cobalt oxide to reducing agent in the pickling slag is 1:(1-10), for example, the molar ratio of cobalt oxide to reducing agent in the pickling slag is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or a value within the range of any two thereof; during the second ammonia leaching process, the molar ratio of cobalt oxide to reducing agent in the first manganese dioxide is 1:(1-10), for example, the molar ratio of cobalt oxide to reducing agent in the first manganese dioxide is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or a value within the range of any two thereof; wherein the molar amount of the reducing agent is measured by the molar amount of the reducing substance.

[0053] In some embodiments, the method further comprises: merging the second-stage leaching solution into an ammonia leaching agent. Merging the second-stage leaching solution into an ammonia leaching agent can recycle the ammonia leaching agent components in the second-stage leaching solution, which is beneficial to improving the ammonia leaching effect.

[0054] In some embodiments, the method further comprises step S4: a. subjecting the first-stage leachate and / or the second-stage leachate to a first-stage evaporation crystallization treatment to obtain crystal a, ammonia, water vapor and a concentrated solution, wherein the crystal a contains ammonium sulfate and the concentrated solution contains a cobalt-ammonia complex, manganese sulfate and ammonium sulfate; b. subjecting the concentrated solution to a second-stage evaporation crystallization treatment to obtain crystal b, which includes ammonium sulfate, cobalt sulfate and manganese sulfate; c. subjecting the crystal b to a roasting treatment under an inert gas to obtain ammonia, sulfur dioxide and a solid mixture, wherein the solid mixture includes cobalt sulfate and manganese sulfate. The present application adopts a first-stage evaporation crystallization treatment to evaporate and precipitate the ammonium sulfate with a higher concentration in the first-stage leachate, and separates the ammonium sulfate crystals, which can be mixed with the evaporated ammonia and water vapor and recycled as a raw material for the ammonia leachate. The concentrated solution is subjected to a second-stage evaporation crystallization treatment, and then the obtained crystal b is roasted to separate ammonia and sulfur dioxide gas, as well as a solid mixture containing cobalt sulfate and manganese sulfate, providing a basis for the subsequent recycling of various materials. Through the above method, the present application can recycle materials without the need to completely separate the intermediate products, which has the advantages of simple process and cost saving.

[0055] In some embodiments, the crystal a, ammonia gas and water vapor obtained in step a are formulated into an ammonia leaching agent for use. Crystal a, ammonia gas and water vapor are solid and gas components obtained in step a, which are easily obtained by phase separation, and the main component of crystal a is ammonium sulfate. Ammonia gas and water vapor can be used to obtain ammonia water through subsequent treatment, which is conducive to preparing an ammonia leaching agent with a high leaching rate for cobalt element and realizing the recycling of resources.

[0056] In some embodiments, step c further includes adding the solid mixture to an acid leaching solution for electrolytic treatment. The cobalt sulfate and manganese sulfate in the solid mixture can be converted into cobalt and manganese dioxide by electrolytic treatment, and a high recovery rate can be achieved without adding additional steps, which has the advantages of simple process and low cost.

[0057] In some embodiments, the ammonia gas and sulfur dioxide obtained in step c are converted back into ammonium sulfate through reaction as an ingredient of the ammonia leaching agent.

[0058] In some embodiments, the conditions of the one-stage evaporation crystallization treatment include: an evaporation temperature of 105-120°C, for example, the evaporation temperature is 105°C, 106°C, 108°C, 109°C, 110°C, 112°C, 113°C, 115°C, 116°C, 117°C, 120°C or a value within the range composed of any two thereof; the cut-off condition is: the mass content of cobalt element in the concentrate is 60-100g / L, for example, 60g / L, 62g / L, 65g / L, 67g / L, 69g / L, 73g / L, 77g / L, 79g / L, 83g / L, 87g / L, 90g / L, 91g / L, 95g / L, 99g / L, 100g / L or a value within the range composed of any two thereof. When the conditions of the first stage evaporation crystallization treatment are controlled to meet the above range, the cobalt element can be reduced from entering the crystal a, the purity of the ammonium cobaltate crystals can be improved, and the leaching effect of the subsequently prepared ammonia leaching agent can be improved.

[0059] In some embodiments, the conditions of the two-stage evaporation crystallization treatment include: an evaporation temperature of 180 to 280°C, and an evaporation time of 2 to 5 hours. Exemplarily, in the two-stage evaporation crystallization treatment, the evaporation temperature is 180°C, 184°C, 189°C, 200°C, 203°C, 211°C, 221°C, 228°C, 237°C, 246°C, 255°C, 259°C, 269°C, 272°C, 280°C, or a value within the range of any two thereof; the evaporation time is 2h, 3h, 4h, 5h, or a value within the range of any two thereof.

[0060] In this process, by controlling the evaporation and crystallization conditions in steps, the ammonium sulfate with a relatively high content is first precipitated, and ammonia gas and water vapor are evaporated at the same time to achieve the recovery of the ammonia leachate. Then, the evaporation and crystallization conditions are adjusted to achieve high-temperature decomposition of the cobalt-ammonia complex to obtain cobalt sulfate. Then, the ammonium sulfate is roasted and decomposed to achieve the separation of cobalt sulfate and manganese sulfate from ammonium sulfate. The cobalt sulfate and manganese sulfate can be further electrolytically recovered to extract valuable elements.

[0061] In some embodiments, in step c, the calcination temperature of the calcination treatment is 350-550° C., the heating rate is 5-15° C. / min, and the calcination time is 0.5-3 h. Exemplarily, the calcination temperature is 350°C, 370°C, 380°C, 410°C, 420°C, 440°C, 440°C, 470°C, 470°C, 500°C, 520°C, 530°C, 540°C, 550°C or a value within the range consisting of any two of them, the heating rate is 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, 11°C / min, 12°C / min, 13°C / min, 14°C / min, 15°C / min or a value within the range consisting of any two of them, and the calcination time is 0.5h, 0.6h, 0.8h, 1.0h, 1.1h, 1.4h, 1.6h, 1.7h, 1.9h, 2.1h, 2.3h, 2.5h, 2.6h, 2.8h, 3h or a value within the range consisting of any two of them.

[0062] In some embodiments, the inert gas is selected from at least one of nitrogen or argon.

[0063] In step c of the present application, during the roasting process, the chemical reaction of ammonium sulfate decomposition at high temperature is shown in Formula 3:

[0064]

[0065] Optionally, after the roasting process is completed, the material may be cooled by natural cooling.

[0066] The scheme of the present application is described below in conjunction with the following specific examples. Unless otherwise specified, the raw materials used in the following examples are all from common commercial products, and the devices or equipment used are all purchased from conventional market sales channels.

[0067] Example 1

[0068] The method for separating nickel and cobalt elements from the anode product of this embodiment is as follows: Figure 1 The process flow diagram shown includes the following steps:

[0069] Step S1, taking the acid leaching solution (i.e. Figure 1The ternary acid leaching solution in the solution was electrolyzed to obtain a nickel-cobalt alloy at the cathode, and 125g of manganese dioxide residue containing nickel and cobalt elements (i.e., anode product) was obtained at the anode. After countercurrent washing 5 times and drying at 320°C for 3h, 117.55g of crude manganese dioxide was obtained. The crude manganese dioxide contained cobalt tetraoxide and nickel trioxide. The content of each substance in the crude manganese dioxide was tested by inductively coupled plasma spectroscopy (ICP), and the calculated content of nickel trioxide was 0.56g, cobalt tetraoxide was 4.60g, and manganese dioxide was 112.34g.

[0070] Step S2: Add 550 ml of 1.5 mol / L sulfuric acid solution to the crude manganese dioxide in step S1 for pickling to remove nickel trioxide, thereby obtaining a pickling solution and pickling residue. Figure 1 The nickel sulfate solution in the solution is returned to the electrolytic treatment process.

[0071] Step S3, the pickled residue is washed 5 times by countercurrent, and then 500 ml of ammonia leaching agent with a total ammonia concentration of 180 g / L is added, and 40.62 g of hydrogen peroxide with a mass concentration of 8% is added as a reducing agent to perform a first-stage ammonia leaching treatment. 4+ The molar ratio of NH3 to the ammonia water is n(NH4 + ):n(NH3)=1:2, the mass ratio of pickling slag to ammonia leaching agent is about 117g:500ml, and the molar ratio of cobalt tetraoxide in pickling slag to H2O2 in hydrogen peroxide is about 1:5. The conditions of the first ammonia leaching treatment include: ammonia leaching pressure of 0.7MPa, ammonia leaching time of 3.5h, ammonia leaching temperature of 65℃, and stirring speed of 150r / min. After the first ammonia leaching treatment, a first leachate and a first manganese dioxide are obtained by filtration. After the first ammonia leaching treatment, the obtained first manganese dioxide is converted to 0.506g of cobalt tetraoxide and 109.4g of manganese dioxide by ICP test.

[0072] Then add a section of manganese dioxide into 200 ml of ammonia leaching agent with a total ammonia concentration of 180 g / L. 4+ The molar ratio of NH3 to the ammonia water is n(NH4 +):n(NH3)=1:2. And 4.47g of hydrogen peroxide with a mass concentration of 8% was added for two-stage ammonia leaching. The mass ratio of the first stage manganese dioxide to the volume ratio of the ammonia leaching agent is 109.9g:200ml, and the molar ratio of the cobalt tetraoxide contained in the first stage manganese dioxide to the H2O2 added to the hydrogen peroxide in the second stage ammonia leaching treatment is 1:5. The conditions for the second stage ammonia leaching treatment include: the ammonia leaching pressure is 0.7MPa, the ammonia leaching time is 3.5h, and the ammonia leaching temperature is 65°C. After the second stage ammonia leaching treatment is completed, the second stage leaching solution and the second stage manganese dioxide are obtained by filtering. After the second stage manganese dioxide is countercurrently washed 5 times, 105.6g of manganese dioxide with a purity of 99.98% is obtained. The second stage leaching solution can be returned to the first stage ammonia leaching process as an ammonia leaching solution for recycling. In this embodiment, in order to calculate the yield of cobalt and manganese elements, both the first and second stage ammonia leaching solutions are evaporated.

[0073] Step S4

[0074] a. Mix the first and second stage leaching solutions and carry out a first stage evaporation crystallization treatment under heating conditions of 105° C. When the mass content of cobalt element in the concentrated solution is 70 g / L, stop evaporation to obtain a concentrated solution, and precipitate ammonium sulfate. The ammonium sulfate, ammonia gas and water vapor obtained by evaporation are prepared into an ammonia leaching agent and then recycled.

[0075] b. The concentrated solution is subjected to a two-stage evaporation crystallization treatment at 200° C. for 3 hours to obtain crystal b (including ammonium sulfate, cobalt sulfate and manganese sulfate). The ammonia gas generated during the two-stage evaporation crystallization process can also be prepared into an ammonia leaching agent for recycling.

[0076] c. The obtained crystal b was roasted in a nitrogen atmosphere at a temperature of 400°C and a heating rate of 10°C / min for 2.5 hours. After the roasting, the temperature was naturally lowered to obtain ammonia, sulfur dioxide and a solid mixture, wherein ammonia and sulfur dioxide were converted into ammonium sulfate by reaction to prepare an ammonia leaching agent. Among them, the solid mixture was 17.63g (cobalt sulfate and manganese sulfate). The obtained solid mixture was measured by flame atomic absorption spectrometry, and 8.19g of cobalt sulfate and 9.44g of manganese sulfate were calculated. The obtained cobalt sulfate and manganese sulfate were returned to the electrolysis process for further electrolysis.

[0077] The yields of cobalt and manganese calculated based on the masses of the obtained cobalt sulfate, manganese sulfate and manganese dioxide are 91.95% and 98.83%, respectively.

[0078] Example 2

[0079] The method for separating nickel and cobalt elements from the anode product of this embodiment comprises the following steps:

[0080] Step S1, after the acid leaching liquid of the nickel-cobalt-manganese ternary positive electrode material is electrolytically treated, 100g of nickel-cobalt manganese dioxide residue is obtained at the anode, and after countercurrent washing 5 times and drying at 320°C for 3h, 94.9g of crude manganese dioxide is obtained. The content of each substance in the crude manganese dioxide is tested by ICP, and the nickel trioxide content is 0.35g, the cobalt tetraoxide content is 10.64g, and the manganese dioxide content is 83.92g.

[0081] Step S2: Add 400 ml of 1.5 mol / L sulfuric acid solution to the crude manganese dioxide in step S1 for pickling to obtain a pickling solution and pickling residue, and return the pickling solution to the electrolysis process.

[0082] Step S3, after the pickling residue is counter-current washed 5 times, 450 ml of ammonia leaching agent with a total ammonia concentration of 180 g / L is added, and 93.86 g of 8% mass concentration hydrogen peroxide is added for a first-stage ammonia leaching treatment, and NH 4+ The molar ratio of NH3 in the ammonia water is n(NH4 + ):n(NH3)=1:2, the mass ratio of pickling slag to ammonia leaching agent is 94.65g:450ml, and the molar ratio of cobalt tetroxide in pickling slag to H2O2 in hydrogen peroxide is 1:5. The conditions of the first ammonia leaching treatment include: ammonia leaching pressure of 0.7MPa, ammonia leaching time of 3.5h, ammonia leaching temperature of 65℃, and stirring speed of 150r / min. After the first ammonia leaching treatment, a first leachate and a first manganese dioxide are obtained by filtration. The first manganese dioxide obtained after the first ammonia leaching contains 1.16g of cobalt tetroxide and 81.7g of manganese dioxide according to ICP test.

[0083] Then add a section of manganese dioxide into 200 ml of ammonia leaching agent with a total ammonia concentration of 180 g / L. 4+ The molar ratio of NH3 in the ammonia water is n(NH4 + ):n(NH3)=1:2, and 10.23g of 8% mass concentration hydrogen peroxide is added for two-stage ammonia leaching. The mass ratio of the first stage manganese dioxide to the volume ratio of the ammonia leaching agent is 82.86g:200ml, and the molar ratio of the cobalt tetraoxide contained in the first stage manganese dioxide to the H2O2 added to the hydrogen peroxide in the second stage ammonia leaching treatment is 1:5. The conditions for the second stage ammonia leaching treatment include: the ammonia leaching pressure is 0.7MPa, the ammonia leaching time is 3.5h, and the ammonia leaching temperature is 65°C. After the second stage ammonia leaching treatment is completed, the second stage leaching solution and the second stage manganese dioxide are filtered, and the second stage manganese dioxide is countercurrently washed 5 times to obtain 78.84g of manganese dioxide with a purity of 99.93%. In this embodiment, in order to calculate the yield of cobalt and manganese elements, both the first and second stage ammonia leaching solutions are evaporated.

[0084] Step S4

[0085] a. Mix the first and second stage leaching solutions and carry out a first stage evaporation crystallization treatment under heating conditions of 115° C. When the mass content of cobalt in the concentrated solution is 80 g / L, stop evaporation to obtain a concentrated solution, and precipitate ammonium sulfate. The ammonium sulfate, ammonia gas and water vapor obtained by evaporation are prepared into an ammonia leaching agent and then recycled.

[0086] b. The concentrated solution is subjected to a two-stage evaporation crystallization treatment at 250° C. for 3 hours to obtain crystal b (ammonium sulfate, cobalt sulfate and manganese sulfate). The ammonia gas generated during the two-stage evaporation crystallization process is prepared into an ammonia leaching agent and recycled.

[0087] c. The obtained crystal b is roasted in a nitrogen atmosphere, the roasting temperature is 500°C, the roasting heating rate is 15°C / min, the roasting is 2h, and the roasting is completed and the temperature is naturally lowered to obtain ammonia, sulfur dioxide and a solid mixture, wherein the ammonia and sulfur dioxide are converted back into ammonium sulfate through reaction to prepare an ammonia leaching agent. Among them, the solid mixture is 30.93g (cobalt sulfate and manganese sulfate). The obtained solid mixture is measured by flame atomic absorption spectrometry, and 18.82g of cobalt sulfate and 6.78g of manganese sulfate are calculated. The obtained cobalt sulfate and manganese sulfate can be returned to the electrolysis process for further electrolysis.

[0088] The yields of cobalt and manganese calculated based on the masses of the obtained cobalt sulfate, manganese sulfate and manganese dioxide are 91.69% and 98.53%, respectively.

[0089] Example 3

[0090] The implementation conditions of Example 3 are the same as those of Example 1, but the total ammonia concentration in the two-stage ammonia leaching is adjusted from 180 g / L in Example 1 to 80 g / L. The purity of manganese dioxide, the yield of cobalt element, and the yield of manganese element obtained in Example 3 are shown in Table 1.

[0091] Example 4

[0092] The implementation conditions of Example 4 are the same as those of Example 1, but the total ammonia concentration in the two-stage ammonia leaching is adjusted from 180 g / L in Example 1 to 230 g / L. The purity of manganese dioxide, the yield of cobalt element, and the yield of manganese element obtained in Example 4 are shown in Table 1.

[0093] Example 5

[0094] Example 5 is implemented under the same conditions as Example 1, but the two-stage ammonia leaching is n (NH4 + The ratio of ):n(NH3) was adjusted from 1:2 in Example 1 to 1:1. The purity of manganese dioxide, the yield of cobalt element and the yield of manganese element obtained in Example 5 are shown in Table 1.

[0095] Example 6

[0096] Example 6 is implemented under the same conditions as Example 1, but the two-stage ammonia leaching is n (NH4 + The ratio of ):n(NH3) was adjusted from 1:2 in Example 1 to 1:3. The purity of manganese dioxide, the yield of cobalt element and the yield of manganese element obtained in Example 6 are shown in Table 1.

[0097] Example 7

[0098] The method for separating nickel and cobalt elements from the anode product of this embodiment comprises the following steps:

[0099] Step S1, taking the manganese dioxide residue containing nickel and cobalt elements obtained from the same anode as Example 1, countercurrent washing and drying to obtain 117.55g of crude manganese dioxide (including 0.56g of nickel trioxide, 4.60g of cobalt tetraoxide and 112.34g of manganese dioxide).

[0100] Step S2: Add 550 ml of 1.5 mol / L sulfuric acid solution to the crude manganese dioxide in step S1 for pickling to remove nickel trioxide therein, thereby obtaining a pickling solution and pickling residue, and the pickling solution is returned to the electrolytic treatment process.

[0101] Step S3, the pickled residue is washed 5 times by countercurrent, and then 500 ml of ammonia leaching agent with a total ammonia concentration of 180 g / L is added, and 40.62 g of hydrogen peroxide with a mass concentration of 8% is added as a reducing agent to perform a first-stage ammonia leaching treatment. 4+ The molar ratio of NH3 to the ammonia water is n(NH4 + ):n(NH3)=1:2, the mass ratio of pickling slag to ammonia leaching agent is 117g:500ml, and the molar ratio of cobalt tetraoxide in pickling slag to H2O2 in hydrogen peroxide is 1:5. The conditions of the first stage ammonia leaching treatment include: ammonia leaching pressure of 0.7MPa, ammonia leaching time of 7h, ammonia leaching temperature of 65℃, and stirring speed of 150r / min. After the first stage ammonia leaching treatment is completed, a first stage leaching solution and a first stage manganese dioxide are obtained by filtration. After the first stage manganese dioxide is countercurrently washed 5 times, 110.03g of manganese dioxide with a purity of 99.53% is obtained. In this embodiment, the first stage leaching solution is evaporated to calculate the yield of cobalt and manganese elements.

[0102] Step S4

[0103] a. Perform a first-stage evaporation and crystallization treatment on a first-stage leaching solution under heating conditions of 105° C. When the mass content of cobalt element in the concentrated solution is 70 g / L, stop evaporation to obtain a concentrated solution, and precipitate ammonium sulfate. The ammonium sulfate, ammonia gas and water vapor obtained by evaporation are prepared into an ammonia leaching agent and then recycled.

[0104] b. The concentrated solution is subjected to a two-stage evaporation crystallization treatment at 200° C. for 3 hours to obtain crystal b (including ammonium sulfate, cobalt sulfate and manganese sulfate). The ammonia gas generated during the two-stage evaporation crystallization process can also be prepared into an ammonia leaching agent for recycling.

[0105] c. The obtained crystal b was roasted in a nitrogen atmosphere at a temperature of 400°C, a heating rate of 10°C / min, and 2.5 hours. After the roasting, the temperature was naturally lowered to obtain ammonia, sulfur dioxide and a solid mixture, wherein ammonia and sulfur dioxide were converted into ammonium sulfate by reaction to prepare an ammonia leaching agent. Among them, the solid mixture was 10.82g (cobalt sulfate and manganese sulfate). The obtained solid mixture was measured by flame atomic absorption spectrometry, and 7.47g of cobalt sulfate and 1.42g of manganese sulfate were calculated. The obtained cobalt sulfate and manganese sulfate were returned to the electrolysis process for further electrolysis.

[0106] The yields of cobalt and manganese calculated based on the masses of the obtained cobalt sulfate, manganese sulfate and manganese dioxide are 84.09% and 98.70%, respectively.

[0107] Comparative Example 1

[0108] Comparative Example 1 was implemented under the same conditions as Example 1, but the total ammonia concentration of the ammonia leaching solution used in the ammonia leaching was adjusted from 180 g / L in Example 1 to 70 g / L. The purity of manganese dioxide, the yield of cobalt element, and the yield of manganese element obtained in Comparative Example 1 are shown in Table 1.

[0109] Table 1

[0110]

[0111] It can be seen from the above embodiments and comparative examples that the present application can achieve efficient separation of manganese dioxide and nickel and cobalt elements through the above method, and obtain manganese dioxide products and nickel-cobalt alloys with high purity and high yield. In particular, when the total ammonia concentration in the ammonia leaching agent is controlled to be 80-230 g / L, the leaching effect of the cobalt element can be improved, and the purity of the manganese dioxide product and the yield of the cobalt element and the manganese element can be improved.

[0112] In particular, the present invention regulates the ammonia leaching agent to include ammonium sulfate and ammonia water, and the NH4 + The molar ratio of NH3 in ammonia water is 1:(1-3), which can further improve the leaching effect and increase the yield of cobalt and manganese elements. In particular, the present application adopts a two-stage ammonia leaching process, in which the first stage of ammonia leaching can improve the leaching effect of cobalt elements, while the second stage of ammonia leaching deeply leaches cobalt elements, further improving the purity of manganese dioxide products. In addition, all the leachates from the first stage of ammonia leaching and the second stage of ammonia leaching are used for evaporation and crystallization, which is conducive to further improving the yield of cobalt and manganese elements.

[0113] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for separating nickel and cobalt elements from an anode product, characterized in that: The following steps are involved: Step S1, obtaining a crude manganese dioxide product, wherein the crude manganese dioxide product contains cobalt tetroxide and nickel trioxide; Wherein, the crude manganese dioxide is derived from the anode product; Step S2, subjecting the crude manganese dioxide to pickling treatment to remove nickel trioxide therein, thereby obtaining pickling slag; Step S3, adding an ammonia leaching agent and a reducing agent to the pickled slag for ammonia leaching to remove cobalt tetroxide therein, and then performing solid-liquid separation to obtain a manganese dioxide product; Wherein, the ammonia soaking agent includes ammonium sulfate and ammonia water; The total ammonia concentration in the ammonia soak is 80-230 g / L; The total ammonia concentration is the concentration of NH3 and NH4 + The sum of concentrations.

2. The method according to claim 1, characterized in that The ammonium sulfate NH4 + The molar ratio of NH3 to the ammonia water is 1:(1-3).

3. The method according to claim 1, characterized in that The reducing agent includes at least one of hydrogen peroxide, hydrazine hydrate or hydroxylamine.

4. The method according to any one of claims 1 to 3, characterized in that The ammonia leaching treatment comprises: adding an ammonia leaching agent and a reducing agent to the pickling slag to perform a first stage of ammonia leaching treatment, and separating the solid from the liquid to obtain a first stage of leaching solution and a stage of manganese dioxide; Then, an ammonia leaching agent and a reducing agent are added to the first-stage manganese dioxide to perform a second-stage ammonia leaching treatment, and solid-liquid separation is performed to obtain a second-stage leaching solution and a second-stage manganese dioxide; The second-stage manganese dioxide is washed to obtain the manganese dioxide product.

5. The method according to claim 4, characterized in that The conditions of the first stage ammonia leaching treatment and the second stage ammonia leaching treatment include: Ammonia immersion pressure: 0.5~1Mpa; Ammonia immersion temperature: 60-70°C; Ammonia immersion time: 3 to 5 hours; The conditions of the first-stage ammonia immersion treatment are the same as those of the second-stage ammonia immersion treatment, or the conditions of the first-stage ammonia immersion treatment are different from those of the second-stage ammonia immersion treatment.

6. The method according to claim 4, characterized in that During the first stage of ammonia leaching, the volume ratio of the pickling slag to the ammonia leaching agent is 100g:400-500ml; During the two-stage ammonia leaching process, the volume ratio of the mass of the first-stage manganese dioxide to the ammonia leaching agent is 100g:160-250ml.

7. The method according to claim 4, characterized in that During the ammonia leaching treatment, the molar ratio of cobalt tetraoxide in the pickling slag to the reducing agent is 1:(1-10); During the two-stage ammonia leaching process, the molar ratio of cobalt tetraoxide in the first stage manganese dioxide to the reducing agent is 1:(1-10); Wherein, the molar amount of the reducing agent is based on the molar amount of the reducing substance; Preferably, the method further comprises: merging the second-stage leaching solution into the ammonia leachate.

8. The method according to claim 4, characterized in that The method further comprises step S4: a. subjecting the first-stage leachate and / or the second-stage leachate to a first-stage evaporation crystallization treatment to obtain crystals a, ammonia gas, water vapor and a concentrated solution, wherein the crystals a contain ammonium sulfate, and the concentrated solution contains a cobalt-ammonia complex, manganese sulfate and ammonium sulfate; b. Then, the concentrated solution is subjected to a two-stage evaporation and crystallization process to obtain crystals b, wherein the crystals b include ammonium sulfate, cobalt sulfate and manganese sulfate; c. calcining the crystal b under an inert gas to obtain ammonia, sulfur dioxide and a solid mixture, wherein the solid mixture includes cobalt sulfate and manganese sulfate.

9. The method according to claim 8, characterized in that The conditions of the one-stage evaporation crystallization treatment include: an evaporation temperature of 105-120° C.; a cut-off condition: a mass content of cobalt in the concentrated solution of 60-100 g / L; Preferably, the conditions of the two-stage evaporation crystallization treatment include: evaporation temperature 180-280°C, evaporation time 2-5h; Preferably, the crystal a, ammonia gas and water vapor obtained in step a are prepared into an ammonia soak for use; Preferably, the ammonia gas and sulfur dioxide obtained in step c are converted into ammonium sulfate through reaction and used as ingredients of the ammonia immersion agent.

10. The method according to claim 1, characterized in that In step S1, the method for obtaining the anode product includes: The waste nickel-cobalt-manganese ternary positive electrode material, acid solution and a reducing agent are mixed for acid leaching to obtain an acid leaching solution, and the acid leaching solution is electrolyzed to obtain the anode product; Adding the solid mixture obtained in step c into the acid leaching solution for electrolysis treatment; Preferably, in step S2, the acid used in the pickling treatment is sulfuric acid; the molar concentration of the sulfuric acid is 0.5 to 1.5 mol / L; Preferably, the mass ratio of the crude manganese dioxide to the volume of sulfuric acid is 100g:400-500ml; Preferably, in step S2, a pickling solution is also obtained, wherein the pickling solution contains nickel sulfate, and the pickling solution is added to the acid leaching solution for electrolytic treatment.

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