A method for separating nickel and cobalt elements from anode products

Abstract

This application relates to the technical field of lithium battery material recycling, and specifically relates to a method for separating nickel and cobalt elements from anode products, which specifically includes the following steps: The crude manganese dioxide in the anode product is subjected to pickling treatment to obtain pickling slag. Then, the pickling slag is added with an ammonia leaching agent and a reducing agent for ammonia leaching treatment, and solid-liquid separation is carried out to obtain a manganese dioxide product; the ammonia leaching agent includes 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 pickling treatment and ammonia leaching treatment, this application realizes the efficient separation of manganese dioxide and nickel and cobalt elements in the anode product, and obtains a manganese dioxide product with high purity and high yield.

Description

Technical Field

[0001] This application relates to the technical field of lithium battery material recycling, and specifically relates 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 applications in the fields of 3C digital, new energy vehicles and chemical energy storage due to their excellent rate performance, high safety, high specific capacity and other advantages. However, the average service life of lithium batteries is about 6-8 years, so a large number of retired batteries will be generated. It is reported that the amount of retired batteries will reach 437 GWh in 2030, including 43,200 tons of recoverable lithium equivalent, 1.312 million tons of nickel equivalent, 102,700 tons of cobalt equivalent, and 127,400 tons of manganese equivalent.

[0003] The traditional recycling methods of nickel-cobalt-manganese ternary cathode materials are mainly pyrometallurgy and hydrometallurgy, and some literatures also introduce biological leaching methods, etc. However, the pyrometallurgical treatment equipment and process have high costs, high energy consumption, and insignificant economic benefits. Hydrometallurgy requires the use of a large amount of organic solvents for extraction, bringing environmental pollution risks. The biological leaching method is still in the laboratory verification stage and has a long leaching time, making it difficult to industrialize. The current relatively advanced method for recycling nickel-cobalt-manganese ternary lithium batteries is to acidify the ternary cathode material with acid + reducing agent, recover nickel and cobalt metals at the cathode by electrolysis, recover manganese element in the form of manganese dioxide at the anode, and recover lithium element in the form of lithium salt in the solution. However, a small amount of cobalt tetroxide and nickel sesquioxide will be doped in the anode product manganese dioxide. This doped product reduces the purity of manganese dioxide on the one hand and the recovery rate of nickel and cobalt metals on the other hand. Dissolving and washing cobalt tetroxide and nickel sesquioxide in it by the method of acid + reducing agent acid dissolution faces the problems of synchronous dissolution of manganese dioxide and low nickel-cobalt separation efficiency. Therefore, it is an urgent problem to find an efficient process method for separating a small amount of cobalt tetroxide and nickel sesquioxide doped in the anode product manganese dioxide. Summary of the Invention

[0004] In view of this, this application provides a method for separating nickel and cobalt elements from anode products. Combining pickling and two-stage ammonia leaching process, it can deeply separate nickel and cobalt elements in the anode product manganese dioxide, obtain high-purity manganese dioxide, and has the advantages of high efficiency, solvent recyclability, economy and environmental protection.

[0005] The method for separating nickel and cobalt elements from anode products provided by this application includes the following steps: Step S1, obtaining crude manganese dioxide. The crude manganese dioxide contains impurities cobalt tetroxide and nickel sesquioxide. Among them, the crude manganese dioxide is from anode products; Step S2, performing pickling treatment on the crude manganese dioxide to remove nickel sesquioxide therein, obtaining pickling slag; Step S3, adding ammonia leaching agent and reducing agent to the pickling slag for ammonia leaching treatment to remove cobalt tetroxide therein, and then performing solid-liquid separation to obtain manganese dioxide products; wherein, the ammonia leaching agent includes ammonium sulfate and ammonia water, and 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. For the crude manganese dioxide obtained by electrolysis, this 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 coordinated to convert the cobalt element into a complex solution, thereby realizing the efficient separation of manganese dioxide from 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 the improvement of the added value of products.

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

[0007] In some embodiments, the molar ratio of NH4 + in ammonium sulfate to NH3 in ammonia water in the ammonia leaching agent is 1:(1-3). Using ammonium sulfate and ammonia water in combination as the ammonia leaching agent, NH3 in the ammonia water can form complex ions with divalent cobalt ions in manganese dioxide and exist in the form of a solution to achieve the separation of cobalt elements from the crude manganese dioxide. This application regulates the molar ratio of NH4 + in ammonium sulfate to NH3 in ammonia water in the ammonia leaching agent to meet the above range, which can better promote their coordination effect, improve the leaching rate of cobalt elements, and is beneficial to further improving 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 ammonia leaching agent and reducing agent to the pickling slag for one-stage ammonia leaching treatment, performing solid-liquid separation to obtain one-stage leachate and one-stage manganese dioxide; then adding ammonia leaching agent and reducing agent to the one-stage manganese dioxide for two-stage ammonia leaching treatment, performing solid-liquid separation to obtain two-stage leachate and two-stage manganese dioxide; washing the two-stage manganese dioxide to obtain manganese dioxide products. This application adopts two-stage ammonia leaching treatment, which can deeply leach cobalt elements in the pickling slag, is beneficial to further improving the purity of manganese dioxide products and the recovery rate of cobalt elements.

[0010] In some embodiments, the conditions for the first-stage ammonia leaching treatment and the second-stage ammonia leaching treatment include: ammonia leaching pressure: 0.5 - 1 Mpa; ammonia leaching temperature: 60 - 70 °C; ammonia leaching time: 3 - 5 h; wherein, the conditions for the first-stage ammonia leaching treatment are the same as those for the second-stage ammonia leaching treatment, or the conditions for the first-stage ammonia leaching treatment are different from those for the second-stage ammonia leaching treatment.

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

[0012] In some embodiments, during the first-stage ammonia leaching treatment, the molar ratio of cobalt spinel to the reducing agent in the pickling residue is 1: (1 - 10); during the second-stage ammonia leaching treatment, the molar ratio of cobalt spinel to the reducing agent in the manganese dioxide in the first stage 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 above method further includes step S4: a. Perform first-stage evaporation crystallization on the first-stage leaching solution and / or the second-stage leaching solution to obtain crystal a, ammonia gas, 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. Then perform second-stage evaporation crystallization on the concentrated solution to obtain crystal b, and crystal b includes ammonium sulfate, cobalt sulfate, and manganese sulfate; c. Roast crystal b under an inert gas to obtain ammonia gas, sulfur dioxide, and a solid mixture, wherein the solid mixture includes cobalt sulfate and manganese sulfate. In this process, by first performing high-temperature crystallization on the first-stage leaching solution, more ammonium sulfate can be precipitated first. The precipitated ammonium sulfate is mixed with the evaporated ammonia gas and water vapor to re-prepare the ammonia leaching agent, improving the recovery rate of the ammonia leaching agent and enabling the effective recycling of the ammonia leaching agent. Then, the cobalt ammonia complex, manganese sulfate, and ammonium sulfate remaining in the concentrated solution are continuously subjected to evaporation crystallization treatment. The cobalt ammonia complex decomposes at high temperature to obtain cobalt sulfate and ammonia gas, converting cobalt into the corresponding sulfate salt, providing the possibility for the subsequent electrolytic extraction of Co element. Then, by roasting, ammonium sulfate is separated from cobalt sulfate and manganese sulfate to obtain cobalt and manganese sulfate salts, and the Co element and Mn element can be continuously electrolytically recovered. In this process, by combining secondary evaporation crystallization treatment and roasting on the first-stage leaching solution, not only the ammonia leaching solution is recycled, but also the recovery rates of Co element and Mn element are improved.

[0014] In some embodiments, the conditions for the first-stage evaporation crystallization treatment include: an evaporation temperature of 105-120°C; the cut-off condition is that 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: an evaporation temperature of 180-280°C and an evaporation time of 2-5 h.

[0015] In some embodiments, the crystalline a, ammonia gas, and water vapor obtained in step a are formulated into an ammonia leaching agent for use.

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

[0017] In some embodiments, in step c, the roasting temperature for the roasting treatment is 350-550°C, the heating rate is 5-15°C / min, and the roasting 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, it further includes: combining the second-stage leaching solution into the ammonia leaching agent. The second-stage leaching solution can be subjected to evaporation crystallization treatment or can also be combined into the 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 cathode material, acid solution, and reducing agent for acid leaching treatment to obtain an acid leaching solution, and performing electrolysis treatment on the acid leaching solution to obtain the anode product; adding the solid mixture obtained in step c into the acid leaching solution for electrolysis treatment. Adding the solid mixture of cobalt sulfate and manganese sulfate obtained in step c into the acid leaching solution for continuous electrolysis improves the recovery rates of Co element and Mn element.

[0020] In the present application, the nickel cobalt manganese ternary cathode material can be obtained by using methods known in the art. For example, by disassembling a nickel cobalt manganese ternary lithium-ion battery, the waste nickel cobalt manganese ternary cathode material can be obtained from the positive electrode sheet.

[0021] In some embodiments, the acid leaching treatment can be carried out by using methods known in the art as long as the object of the present application can be achieved. For example, sulfuric acid and hydrogen peroxide can be used for acid leaching treatment of the nickel cobalt manganese ternary cathode material.

[0022] In some embodiments, in the electrolysis treatment, the pH is controlled to be 3-6, and the current density is controlled to be 0.5-3 mA / cm 2 . In the electrolysis 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 for the pickling treatment is sulfuric acid; the molar concentration of sulfuric acid is 0.5-1.5 mol / L.

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

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

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

[0027] In this application, the crude manganese dioxide in the anode product is pickled to separate the residual nickel element, and then the pickling residue is subjected to ammonia leaching treatment. 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, realizing the efficient separation of manganese dioxide from nickel and cobalt elements, and obtaining a manganese dioxide product with high purity and high yield.

[0028] The ammonia leaching solution containing cobalt element, manganese element, etc. is subjected to one-stage evaporation crystallization treatment to separate ammonium sulfate crystals, ammonia gas, and water vapor, which can be recycled as raw materials for the ammonia leaching agent. The obtained concentrated solution is further subjected to two-stage evaporation 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 extracting Co element and Mn element. Among them, the Co element is converted into cobalt alloy, and the Mn element is converted into manganese dioxide, realizing the recycling of materials, improving the recovery rates of Co element and Mn element, 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 Ni element. The nickel-cobalt alloy obtained at the cathode during electrolysis can achieve high recovery rates and high purities.

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

[0031] Figure 1 It is a process flow chart of a method for separating nickel and cobalt elements from the anode product provided in Embodiment 1 of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

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

[0033] During the recovery process of nickel-cobalt-manganese ternary cathode materials, in the anode products obtained by electrolysis, there are often some impurities of Ni element and Co element, which makes the purity of the anode product MnO2 relatively low, and affects the recovery rates of Ni element and Co element. The methods in the prior art often cannot effectively separate the Ni element and Co element in the anode product MnO2, and since the acids and alkalis used in the process cannot be effectively recovered, a large amount of acids and alkalis are 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 anode products, including the following steps: Step S1, obtaining a crude manganese dioxide product, which contains cobalt tetroxide and nickel sesquioxide, wherein the crude manganese dioxide product is from the anode product; Step S2, performing pickling treatment on the crude manganese dioxide product to remove the nickel sesquioxide therein, obtaining a pickling residue; Step S3, adding the pickling residue to an ammonia leaching agent and a reducing agent for ammonia leaching treatment to remove the cobalt tetroxide therein, and then performing solid-liquid separation to obtain a manganese dioxide product; wherein, the ammonia leaching agent includes ammonium sulfate and ammonia water; 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. The present application uses pickling treatment to recover the residual nickel element in the crude manganese dioxide product, realizing the efficient separation of manganese dioxide and nickel element. Then, the pickling residue is subjected to ammonia leaching treatment. By controlling the total ammonia concentration in the ammonia leaching agent, the ammonia leaching agent and the reducing agent are closely coordinated to convert the cobalt element into a complex solution, and then solid-liquid separation is performed to achieve the efficient separation of manganese dioxide and cobalt element, obtaining a manganese dioxide product with high purity and high yield. In addition, the nickel-containing pickling solution and the leaching solution containing cobalt and manganese elements can be treated by electrolysis to obtain nickel-cobalt alloy and manganese dioxide, improving the recovery rates of nickel, cobalt and manganese.

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

[0036] In some embodiments, in step S2, the acid used for pickling treatment is sulfuric acid; the molar concentration of sulfuric acid is 0.5 - 1.5 mol / L, such as 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 values within the range composed of any two of them.

[0037] In some embodiments, the mass ratio of crude manganese dioxide to the volume of sulfuric acid is 100 g : 400 - 500 ml. For example, when the mass of crude manganese dioxide is 100 g, the corresponding 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 values within the range composed of any two of them.

[0038] Through the above pickling treatment, this application can remove nickel sesquioxide. By using sulfuric acid and controlling the molar concentration within the above range, under relatively low sulfuric acid concentration conditions, nickel sesquioxide is converted into nickel sulfate and washed out. However, cobalt tetroxide and manganese dioxide contained in the crude manganese dioxide can only react with sulfuric acid under the participation of a reducing agent (such as hydrogen peroxide). Therefore, pickling can separate cobalt and nickel elements. Pre - removing nickel by pickling treatment can prevent nickel elements from forming nickel - ammonia sulfate complexes during subsequent ammonia leaching. This complex has strong stability and it is difficult to separate nickel elements from the nickel - ammonia sulfate complex by high - temperature roasting. After the pickling treatment, pickling solution and pickling residue are obtained. Among them, the pickling solution can be returned to the above electrolysis treatment to convert nickel elements into nickel - cobalt alloy.

[0039] In this application, the reaction equation between sulfuric acid and nickel sesquioxide in the pickling treatment is shown in Equation 1:

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

[0041] The reaction equation for the reaction between cobalt tetroxide and sulfuric acid under the participation of hydrogen peroxide is shown in Equation 2:

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

[0043] In this application, it also includes: before the ammonia leaching treatment, washing the pickling residue until the pH is 6.5 - 7. The washing can be carried out with deionized water, and drying treatment (such as drying) can be carried out after washing.

[0044] In this application, the total ammonia concentration in the ammonia leaching agent is 80 - 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 any value within the range composed of any two of them. By adjusting the total ammonia concentration of the ammonia leaching agent to meet the above range in this application, excellent leaching effect on cobalt elements in pickling residues can be ensured, the purity and yield of manganese dioxide products can be improved, and the yield of nickel-cobalt alloys can be increased.

[0045] In some embodiments, the molar ratio of NH4 in ammonium sulfate to NH3 in ammonia water in the ammonia leaching agent is 1:(1 - 3). For example, the molar ratio of NH4 in ammonium sulfate to 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 any value within the range composed of any two of these numerical ratios. Using ammonium sulfate and ammonia water in combination as the ammonia leaching agent, NH3 in the ammonia water can form complex ions with divalent cobalt ions in manganese dioxide and exist in the form of a solution, realizing the separation of cobalt elements from crude manganese dioxide. By adjusting the molar ratio of NH4 in ammonium sulfate to NH3 in ammonia water in the ammonia leaching agent in this application to meet the above range, the complexation of the two can be better promoted, the leaching rate of cobalt elements can be increased, which is beneficial to further improving the purity of manganese dioxide products and the yield of nickel-cobalt alloys. + and ammonia water is 1:(1 - 3). For example, the molar ratio of NH4 in ammonium sulfate + and 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 any value within the range composed of any two of these numerical ratios. Using ammonium sulfate and ammonia water in combination as the ammonia leaching agent, NH3 in the ammonia water can form complex ions with divalent cobalt ions in manganese dioxide and exist in the form of a solution, realizing the separation of cobalt elements from crude manganese dioxide. By adjusting the molar ratio of NH4 in ammonium sulfate to NH3 in ammonia water in the ammonia leaching agent in this application to meet the above range, the complexation of the two can be better promoted, the leaching rate of cobalt elements can be increased, which is beneficial to further improving the purity of manganese dioxide products and the yield of nickel-cobalt alloys. + and ammonia water in the ammonia leaching agent to meet the above range can better promote their complexation, improve the leaching rate of cobalt elements, and is beneficial to further improving the purity of manganese dioxide products and the yield of nickel-cobalt alloys.

[0046] In some embodiments, the reducing agent includes at least one of hydrogen peroxide, hydrazine hydrate, or hydroxylamine. Using these reducing agents can better reduce cobalt tetroxide in crude manganese dioxide to divalent cobalt ions, thereby forming complex ions with NH3, improving the ammonia leaching efficiency, and not introducing additional cation impurities, which is beneficial to improving the purity of products and intermediate products.

[0047] In some more preferred embodiments, the ammonia leaching treatment includes: adding an ammonia leaching agent and a reducing agent to the pickling residue for a first-stage ammonia leaching treatment, followed by solid-liquid separation to obtain a first-stage leaching solution and 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, followed by solid-liquid separation to obtain a second-stage leaching solution and second-stage manganese dioxide; washing the second-stage manganese dioxide to obtain a manganese dioxide product. In this application, two-stage ammonia leaching is used for treatment. In the first-stage leaching solution, cobalt elements exist in the form of cobalt hexammine sulfate (Co(NH3)6SO4, where the hexamminecobalt ion is Co(NH3)6 2+ ), and a small amount of manganese elements exist in the form of Mn 2+ . Performing a second-stage ammonia leaching on the first-stage manganese dioxide can further deeply leach cobalt ions and improve the purity of the manganese dioxide product.

[0048] In some embodiments, the conditions for the first-stage ammonia leaching treatment and the second-stage ammonia leaching treatment include: ammonia leaching pressure: 0.5 - 1 Mpa; ammonia leaching temperature: 60 - 70 °C; ammonia leaching time: 3 - 5 h; wherein, the conditions for the first-stage ammonia leaching treatment are the same as those for the second-stage ammonia leaching treatment, or the conditions for the first-stage ammonia leaching treatment are different from those for the second-stage ammonia leaching treatment.

[0049] In some exemplary embodiments, the ammonia leaching pressure is 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa or a value within the range composed of any two of them, the ammonia leaching 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 composed of any two of them, and the ammonia leaching time is 3 h, 3.2 h, 3.7 h, 4.1 h, 4.5 h, 4.8 h, 5 h or a value within the range composed of any two of them. When controlling the first-stage ammonia leaching treatment and the second-stage ammonia leaching treatment to meet the above conditions, the leaching efficiency and leaching degree of the ammonia leaching agent for cobalt elements can be improved, and the purity of the manganese dioxide product can be further improved.

[0050] In some embodiments, during the first-stage ammonia leaching treatment, the mass ratio of the pickling residue to the volume of the ammonia leaching agent is 100 g: 400 - 500 ml. For example, when the mass of the pickling residue is 100 g, the volume of the ammonia leaching agent used correspondingly 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 composed of any two of them.

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

[0052] In some embodiments, during a period of ammonia leaching treatment, the molar ratio of cobalt ferrite to the reducing agent in the pickling residue is 1:(1-10). For example, the molar ratio of cobalt ferrite to the reducing agent in the pickling residue 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 composed of any two of them; during the second-stage ammonia leaching treatment, the molar ratio of cobalt ferrite to the reducing agent in the first-stage manganese dioxide is 1:(1-10). For example, the molar ratio of cobalt ferrite to the reducing agent in the first-stage 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 composed of any two of them; wherein, the molar amount of the reducing agent is calculated based on the molar amount of the reducing substance.

[0053] In some embodiments, the above method further includes: combining the second-stage leaching solution into the ammonia leaching agent. Combining the second-stage leaching solution into the ammonia leaching agent can enable the components of the ammonia leaching agent in the second-stage leaching solution to be recycled, which is beneficial to improving the ammonia leaching effect.

[0054] In some embodiments, the above method further includes step S4: a. Performing first-stage evaporation crystallization on the first-stage leaching solution and / or the second-stage leaching solution to obtain crystal a, ammonia gas, 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. Then performing second-stage evaporation crystallization on the concentrated solution to obtain crystal b, and crystal b includes ammonium sulfate, cobalt sulfate, and manganese sulfate; c. Roasting crystal b under an inert gas to obtain ammonia gas, sulfur dioxide, and a solid mixture, wherein the solid mixture includes cobalt sulfate and manganese sulfate. In this application, first-stage evaporation crystallization treatment is adopted to precipitate ammonium sulfate with a relatively high concentration in the first-stage leaching solution through evaporation, and the separated ammonium sulfate crystal can be mixed with the evaporated ammonia gas and water vapor to be used as the raw material of the ammonia leaching agent for recycling. Performing second-stage evaporation crystallization on the concentrated solution and then roasting the obtained crystal b can separate ammonia gas and sulfur dioxide gas, as well as a solid mixture containing cobalt sulfate and manganese sulfate, providing a basis for the recycling of each subsequent material. Through the above method, this application can recycle materials without completely and thoroughly separating each intermediate product, having the advantages of simple process and cost savings.

[0055] In some embodiments, 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 the solid and gas components obtained in step a, which are easily obtained through phase separation. Moreover, the main component of crystal a is ammonium sulfate, and ammonia gas and water vapor can be processed to obtain ammonia water later, which is beneficial to preparing an ammonia leaching agent with a high leaching rate for cobalt elements and realizing the recycling of resources.

[0056] In some embodiments, in step c, it further includes adding the solid mixture into the acid leaching solution for electrolysis treatment. Through the electrolysis treatment, cobalt sulfate and manganese sulfate in the solid mixture can be converted into cobalt metal and manganese dioxide, achieving a high recovery rate without the need to additionally increase steps, and having the advantages of simple process and low cost.

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

[0058] In some embodiments, the conditions for the first-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 values within the range composed of any two of them; the cut-off condition is: the mass content of cobalt element in the concentrated solution is 60 - 100 g / L. For example, 60 g / L, 62 g / L, 65 g / L, 67 g / L, 69 g / L, 73 g / L, 77 g / L, 79 g / L, 83 g / L, 87 g / L, 90 g / L, 91 g / L, 95 g / L, 99 g / L, 100 g / L or values within the range composed of any two of them. When the conditions for the first-stage evaporation crystallization treatment are controlled to meet the above range, the entry of cobalt element into crystal a can be reduced, the purity of ammonium cobaltate crystal can be improved, which is beneficial to improving the leaching effect of the subsequently prepared ammonia leaching agent.

[0059] In some embodiments, the conditions for the second-stage evaporation crystallization treatment include: an evaporation temperature of 180 - 280°C and an evaporation time of 2 - 5 h. Exemplarily, in the second-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 values within the range composed of any two of them; the evaporation time is 2 h, 3 h, 4 h, 5 h or values within the range composed of any two of them.

[0060] In this process, by stepwise controlling the evaporation crystallization conditions, ammonium sulfate with a relatively high content is first precipitated, and at the same time, ammonia gas and water vapor are distilled out to realize the recovery of the ammonia leaching agent. Then, the conditions of evaporation crystallization are adjusted to achieve the high-temperature decomposition of the cobalt ammonia complex to obtain cobalt sulfate. After that, ammonium sulfate is calcined and decomposed to separate cobalt sulfate and manganese sulfate from ammonium sulfate, and valuable elements can be continuously electrolytically recovered from cobalt sulfate and manganese sulfate.

[0061] In some embodiments, in step c, the calcination temperature for the calcination treatment is 350 to 550 °C, the heating rate is 5 to 15 °C / min, and the calcination time is 0.5 to 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 composed 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 composed of any two of them; the calcination time is 0.5 h, 0.6 h, 0.8 h, 1.0 h, 1.1 h, 1.4 h, 1.6 h, 1.7 h, 1.9 h, 2.1 h, 2.3 h, 2.5 h, 2.6 h, 2.8 h, 3 h or a value within the range composed 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 calcination treatment, the chemical reaction occurring during the high-temperature decomposition of ammonium sulfate is shown in Equation 3:

[0064]

[0065] Optionally, after the calcination treatment, natural cooling can be used for cooling.

[0066] The solution of the present application will be described below in conjunction with the following specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments are all from ordinary commercially available 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 in this example refers to Figure 1 the process flow chart shown, and includes the following steps:

[0069] Step S1: Take the leaching solution after acid leaching of the nickel-cobalt-manganese ternary cathode material (i.e., Figure 1The ternary acid leaching solution) is subjected to electrolysis treatment to obtain a nickel-cobalt alloy at the cathode and a manganese dioxide residue containing nickel and cobalt elements, 125 g (i.e., the anode product), at the anode. After being washed 5 times by countercurrent and dried at 320 °C for 3 h, 117.55 g of crude manganese dioxide is obtained. The crude manganese dioxide contains cobalt tetroxide and nickel sesquioxide. The content of each substance in the crude manganese dioxide is measured by inductively coupled plasma spectroscopy (ICP). After calculation, the content of nickel sesquioxide is 0.56 g, the content of cobalt tetroxide is 4.60 g, and the content of manganese dioxide is 112.34 g.

[0070] Step S2: Add 550 ml of sulfuric acid solution with a molar concentration of 1.5 mol / L to the crude manganese dioxide in Step S1 for pickling treatment to remove nickel sesquioxide therein, obtaining a pickling solution and pickling residues. The pickling solution (i.e., Figure 1 the nickel sulfate solution therein) is returned to the electrolysis treatment process.

[0071] Step S3: Wash the pickling residues 5 times by countercurrent, then add 500 ml of an ammonia leaching agent with a total ammonia concentration of 180 g / L, and add 40.62 g of hydrogen peroxide with a mass concentration of 8% as a reducing agent for one-stage ammonia leaching treatment. Among them, the molar ratio of NH 4+ in ammonium sulfate and NH3 in the ammonia water is n(NH4 + ):n(NH3)=1:2. The mass ratio of the pickling residues to the volume of the ammonia leaching agent is approximately 117 g:500 ml. The molar amount ratio of cobalt tetroxide in the pickling residues to H2O2 in hydrogen peroxide is approximately 1:5. The conditions for the one-stage ammonia leaching treatment include: ammonia leaching pressure of 0.7 MPa, ammonia leaching time of 3.5 h, ammonia leaching temperature of 65 °C, and stirring speed of 150 r / min. After the one-stage ammonia leaching treatment, filter to obtain a one-stage leaching solution and one-stage manganese dioxide. After the one-stage ammonia leaching treatment, the obtained one-stage manganese dioxide is measured by ICP and converted to contain 0.506 g of cobalt tetroxide and 109.4 g of manganese dioxide.

[0072] Then add 200 ml of an ammonia leaching agent with a total ammonia concentration of 180 g / L to the one-stage manganese dioxide. The NH 4+ in ammonium sulfate and +): n(NH3) = 1:2. And 4.47 g of hydrogen peroxide with a mass concentration of 8% was added for the second-stage ammonia leaching. The mass ratio of manganese dioxide in the first stage to the volume of the ammonia leaching agent was 109.9 g:200 ml, and the molar ratio of cobalt tetroxide contained in the manganese dioxide in the first stage to the amount of H2O2 in the hydrogen peroxide added in the second-stage ammonia leaching treatment was 1:5. The conditions for the second-stage ammonia leaching treatment included: the ammonia leaching pressure was 0.7 MPa, the ammonia leaching time was 3.5 h, and the ammonia leaching temperature was 65°C. After the second-stage ammonia leaching treatment, the second-stage leachate and the second-stage manganese dioxide were obtained by filtration. After the second-stage manganese dioxide was washed countercurrently 5 times, 105.6 g of manganese dioxide with a purity of 99.98% was obtained. The second-stage leachate could be returned to the first-stage ammonia leaching treatment process for recycling as the ammonia leaching solution. In this example, evaporation treatment was performed on both the first-stage and second-stage ammonia leaching solutions to calculate the recovery rates of cobalt and manganese elements.

[0073] Step S4

[0074] a. After mixing the first-stage and second-stage leachates, perform the first-stage evaporation crystallization treatment under heating conditions at 105°C. Stop evaporation when the mass content of cobalt element in the concentrated solution reaches 70 g / L to obtain the concentrated solution, and ammonium sulfate is precipitated. The ammonium sulfate, ammonia gas, and water vapor obtained by evaporation are formulated into an ammonia leaching agent for recycling.

[0075] b. Perform the second-stage evaporation crystallization treatment on the concentrated solution at 200°C for 3 h to obtain Crystal b (including ammonium sulfate, cobalt sulfate, and manganese sulfate). The ammonia gas generated during the second-stage evaporation crystallization process can also be formulated into an ammonia leaching agent for recycling.

[0076] c. Roast the obtained Crystal b under a nitrogen protection atmosphere. The roasting temperature is 400°C, the roasting heating rate is 10°C / min, and roast for 2.5 h. After roasting, cool naturally to obtain ammonia gas, sulfur dioxide, and a solid mixture. Among them, the ammonia gas and sulfur dioxide are re-converted into ammonium sulfate through reaction for preparing the ammonia leaching agent. Among them, the solid mixture is 17.63 g (cobalt sulfate and manganese sulfate). The obtained solid mixture was measured by flame atomic absorption spectrometry, and it was calculated that there was 8.19 g of cobalt sulfate and 9.44 g of manganese sulfate. The obtained cobalt sulfate and manganese sulfate are returned to the electrolysis treatment process for continuous electrolysis.

[0077] According to the masses of the obtained cobalt sulfate, manganese sulfate, and manganese dioxide, the recovery rates of cobalt element and manganese element were calculated to be 91.95% and 98.83% respectively.

[0078] Example 2

[0079] The method for separating nickel and cobalt elements from the anode product in this example includes 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-stage and second-stage leachates and perform first-stage evaporation crystallization treatment under heating at 115°C. Stop evaporation when the mass content of cobalt element in the concentrated solution reaches 80 g / L to obtain the concentrated solution and precipitate ammonium sulfate. Prepare the ammonia leaching agent from the ammonium sulfate, ammonia gas, and water vapor obtained by evaporation for recycling.

[0086] b. Perform second-stage evaporation crystallization treatment on the concentrated solution at 250°C for 3 h to obtain Crystal b (ammonium sulfate, cobalt sulfate, and manganese sulfate). The ammonia gas generated during the second-stage evaporation crystallization process is prepared into an ammonia leaching agent for recycling.

[0087] c. Roast the obtained Crystal b under a nitrogen protection atmosphere. The roasting temperature is 500°C, the roasting heating rate is 15°C / min, and the roasting time is 2 h. After roasting, cool naturally to obtain ammonia gas, sulfur dioxide, and a solid mixture. Among them, ammonia gas and sulfur dioxide are re-converted into ammonium sulfate through reaction for preparing the ammonia leaching agent. Among them, the solid mixture is 30.93 g (cobalt sulfate and manganese sulfate). Use the flame atomic absorption spectrometry to measure the obtained solid mixture, and calculate that the cobalt sulfate is 18.82 g and the manganese sulfate is 6.78 g. The obtained cobalt sulfate and manganese sulfate can be returned to the electrolysis treatment process for continuous electrolysis.

[0088] Calculate the recovery rates of cobalt element and manganese element to be 91.69% and 98.53% respectively according to the masses of the obtained cobalt sulfate, manganese sulfate, and manganese dioxide.

[0089] Example 3

[0090] Example 3 has the same implementation conditions as 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 recovery rate of cobalt element, and the recovery rate of manganese element obtained in Example 3 are shown in Table 1.

[0091] Example 4

[0092] Example 4 has the same implementation conditions as 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 recovery rate of cobalt element, and the recovery rate of manganese element obtained in Example 4 are shown in Table 1.

[0093] Example 5

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

[0095] Example 6

[0096] Example 6 has the same implementation conditions as Example 1, but the ratio of n(NH4 + ):n(NH3) in the two-stage ammonia leaching is adjusted from 1:2 in Example 1 to 1:3. The purity of manganese dioxide, the recovery rate of cobalt element, and the recovery rate 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 in this example includes the following steps:

[0099] Step S1: Take the manganese dioxide residue containing nickel and cobalt elements obtained from the same anode as in Example 1, and obtain 117.55 g of crude manganese dioxide after countercurrent washing and drying (where the content of nickel sesquioxide is 0.56 g, the content of cobalt tetroxide is 4.60 g, and the content of manganese dioxide is 112.34 g).

[0100] Step S2: Add 550 ml of sulfuric acid solution with a molar concentration of 1.5 mol / L to the crude manganese dioxide in Step S1 for pickling treatment to remove nickel sesquioxide therein, obtaining pickling solution and pickling residue. The pickling solution is returned to the electrolysis treatment process.

[0101] Step S3: Wash the pickling residue countercurrently 5 times, then add 500 ml of ammonia leaching agent with a total ammonia concentration of 180 g / L, and add 40.62 g of hydrogen peroxide with a mass concentration of 8% as a reducing agent for one-stage ammonia leaching treatment. Among them, the molar ratio of NH 4+ in ammonium sulfate and NH3 in the ammonia water is n(NH4 + ):n(NH3) = 1:2, the mass ratio of the pickling residue to the volume of the ammonia leaching agent is 117 g:500 ml, and the molar amount ratio of cobalt tetroxide in the pickling residue to H2O2 in hydrogen peroxide is 1:5. The conditions for the one-stage ammonia leaching treatment include: ammonia leaching pressure is 0.7 MPa, ammonia leaching time is 7 h, ammonia leaching temperature is 65 °C, and stirring speed is 150 r / min. After the one-stage ammonia leaching treatment, filter to obtain one-stage leachate and one-stage manganese dioxide. After washing the one-stage manganese dioxide countercurrently 5 times, 110.03 g of manganese dioxide with a purity of 99.53% is obtained. In this example, evaporation treatment is performed on the one-stage leachate for calculating the recovery rates of cobalt and manganese elements.

[0102] Step S4

[0103] a. Perform one-stage evaporation crystallization treatment on the one-stage leachate under the heating condition of 105 °C. Stop evaporation when the mass content of cobalt element in the concentrated solution reaches 70 g / L, obtain the concentrated solution, and precipitate ammonium sulfate. The ammonium sulfate is formulated with the evaporated ammonia gas and water vapor into an ammonia leaching agent for recycling.

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

[0105] c. The obtained Crystal b is roasted under a nitrogen protection atmosphere. The roasting temperature is 400 °C, the roasting heating rate is 10 °C / min, and the roasting is carried out for 2.5 h. After that, it is naturally cooled to obtain ammonia gas, sulfur dioxide, and a solid mixture. Among them, ammonia gas and sulfur dioxide are re-converted into ammonium sulfate through reaction for preparing the ammonia leaching agent. Among them, the solid mixture is 10.82 g (cobalt sulfate and manganese sulfate). The obtained solid mixture is measured by flame atomic absorption spectrometry, and it is calculated that there are 7.47 g of cobalt sulfate and 1.42 g of manganese sulfate. The obtained cobalt sulfate and manganese sulfate are returned to the electrolysis treatment process for continuous electrolysis.

[0106] According to the masses of the obtained cobalt sulfate, manganese sulfate, and manganese dioxide, the recovery rates of cobalt element and manganese element are calculated to be 84.09% and 98.70% respectively.

[0107] Comparative Example 1

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

[0109] Table 1

[0110]

[0111] From the above examples and comparative examples, it can be seen that through the above method of the present application, the efficient separation of manganese dioxide from nickel and cobalt elements can be achieved, and high-purity and high-recovery manganese dioxide products and nickel-cobalt alloys can be obtained. In particular, when the total ammonia concentration in the ammonia leaching agent is controlled at 80 - 230 g / L, the leaching effect on cobalt element can be improved, and the purity of manganese dioxide products and the recovery rates of cobalt element and manganese element can be improved.

[0112] Particularly, in the present application, by regulating the ammonia leaching agent to include ammonium sulfate and ammonia water, and the molar ratio of NH₄ in ammonium sulfate to NH₃ in ammonia water is 1:(1 - 3), the leaching effect can be further improved, and the recovery rates of cobalt element and manganese element can be increased. In particular, the present application adopts a two-stage ammonia leaching treatment process in cooperation. The first-stage ammonia leaching can improve the leaching effect of cobalt element. At the same time, the second-stage ammonia leaching deeply leaches cobalt element, further improving the purity of manganese dioxide products. In addition, all the leaching solutions from the first-stage ammonia leaching treatment and the second-stage ammonia leaching treatment are used for evaporation crystallization, which is beneficial to further improving the recovery rates of cobalt element and manganese element. +

[0113] ​The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the principles of the present application shall be included within the protection scope of the present application.

Claims

1. A method for separating nickel and cobalt elements from anode products, characterized in that, It includes the following steps: Step S1: Obtain crude manganese dioxide, where the crude manganese dioxide contains cobalt tetroxide and nickel sesquioxide; Among them, the crude manganese dioxide is from the anodic product; Step S2: Perform pickling treatment on the crude manganese dioxide to remove nickel sesquioxide therein, obtaining pickling slag; Step S3: Add the pickling slag to an ammonia leaching agent and a reducing agent for ammonia leaching treatment to remove cobalt tetroxide therein, and then perform solid-liquid separation to obtain a manganese dioxide product; Among them, the ammonia leaching agent includes ammonium sulfate and ammonia water; 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; The acid used for the pickling treatment is sulfuric acid; the molar concentration of the sulfuric acid is 0.5 - 1.5 mol / L.

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

3. The method according to claim 1, wherein 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 includes: adding the ammonia leaching agent and the reducing agent to the pickling slag for first-stage ammonia leaching treatment, performing solid-liquid separation to obtain a first-stage leaching solution and first-stage manganese dioxide; Then add the ammonia leaching agent and the reducing agent to the first-stage manganese dioxide for second-stage ammonia leaching treatment, perform solid-liquid separation to obtain a second-stage leaching solution and second-stage manganese dioxide; Wash the second-stage manganese dioxide to obtain the manganese dioxide product.

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

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

7. The method according to claim 4, wherein During the first-stage ammonia leaching treatment, the molar ratio of cobalt tetroxide in the pickling slag to the reducing agent is 1: (1 - 10); During the second-stage ammonia leaching treatment, the molar ratio of cobalt tetroxide in the first-stage manganese dioxide to the reducing agent is 1: (1 - 10); Among them, the molar amount of the reducing agent is calculated based on the molar amount of the reducing substance.

8. The method according to claim 4, characterized in that, The method further includes: combining the second-stage leaching solution into the ammonia leaching agent.

9. The method according to claim 4, wherein The method further includes step S4: a. Perform first-stage evaporation crystallization treatment on the first-stage leaching solution and / or the second-stage leaching solution to obtain crystal a, ammonia gas, water vapor and concentrated solution, where crystal a contains ammonium sulfate, and the concentrated solution contains cobalt ammonia complex, manganese sulfate and ammonium sulfate; b. Then perform second-stage evaporation crystallization treatment on the concentrated solution to obtain crystal b, and crystal b includes ammonium sulfate, cobalt sulfate and manganese sulfate; c. Roast crystal b under an inert gas to obtain ammonia gas, sulfur dioxide and a solid mixture, where the solid mixture includes cobalt sulfate and manganese sulfate.

10. The method according to claim 9, characterized in that, The conditions for the first-stage evaporation crystallization treatment include: evaporation temperature 105 - 120 °C; the cut-off condition is: the mass content of cobalt element in the concentrated solution is 60 - 100 g / L.

11. The method according to claim 9, wherein The conditions for the secondary evaporation crystallization treatment include: evaporation temperature of 180-280°C and evaporation time of 2-5 h.

12. The method according to claim 9, wherein The crystallization a, ammonia gas, and water vapor obtained in step a are formulated into an ammonia leaching agent for use.

13. The method according to claim 9, wherein The ammonia gas and sulfur dioxide obtained in step c are re-converted into ammonium sulfate through reaction and used as ingredients for the ammonia leaching agent.

14. The method according to claim 1, characterized in that, In step S1, the method for obtaining the anode product includes: Mixing waste nickel cobalt manganese ternary cathode material, acid solution, and reducing agent for acid leaching treatment to obtain an acid leaching solution, and performing electrolysis treatment on the acid leaching solution to obtain the anode product; Adding the solid mixture obtained in step c to the acid leaching solution for electrolysis treatment.

15. The method according to claim 1, characterized in that The mass ratio of the crude manganese dioxide to the volume of sulfuric acid is 100 g: 400-500 ml.

16. The method according to claim 1, characterized in that In step S2, an acid washing solution is also obtained. The acid washing solution contains nickel sulfate. The acid washing solution is added to the acid leaching solution for electrolysis treatment.

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