Step-by-step manganese inhibition leaching method for waste lithium nickel cobalt manganate positive electrode material

Abstract

The invention belongs to the technical field of lithium battery recovery, and particularly relates to a step-by-step manganese inhibition leaching method of a waste lithium nickel cobalt manganate positive electrode material, which comprises the following steps: (1) heating a first acid leaching agent to 70-95 DEG C, adding waste lithium nickel cobalt manganate positive electrode material powder, stirring and leaching, and filtering after leaching to obtain a first filtrate and a first filter residue; (2) heating a second acid leaching agent to 110-150 DEG C, adding the first filter residue in the step (1), adding an additive, stirring and leaching, and filtering after leaching to obtain a second filtrate and a second filter residue; (3) mixing the first filtrate obtained in the step (1) and the second filtrate obtained in the step (2) to obtain a leachate rich in nickel, cobalt and lithium; manganese is enriched in the second filter residue. According to the method, nickel, cobalt and lithium are selectively leached in two steps, manganese is enriched in leaching residues, nickel, cobalt and lithium are separated from manganese, cost reduction and efficiency improvement of the subsequent separation and purification process are facilitated, meanwhile, reagent consumption is reduced, and leaching cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium battery recycling, and in particular relates to a method for step-by-step inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide lithium positive electrode materials. Background Art

[0003] For ternary waste nickel cobalt manganese oxide positive electrode materials, the domestic market basically adopts wet process for recycling. The integration of leaching and extraction technology of wet process has great advantages for the recovery of various valuable metals in complex multi-metal solution systems. Waste nickel cobalt manganese oxide positive electrode materials can be leached with inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid. Since cobalt and manganese in the raw materials exist in high-valent states, it is necessary to introduce reducing agents such as hydrogen peroxide, sodium sulfite and hydroxylamine. Due to pollution and cost issues, sulfuric acid and hydrogen peroxide are generally used for leaching in industry at present, and the leaching temperature is 80°C, which can make the leaching of nickel, cobalt, manganese and lithium in the raw materials more complete. However, this leaching process has safety risks, low hydrogen peroxide utilization efficiency, large reagent consumption, low production efficiency and high cost. At the same time, the nickel, cobalt, manganese and lithium in the raw materials are leached together, which also increases the difficulty and process cost of subsequent extraction and separation processes.

[0004] The nickel, cobalt and lithium in the waste nickel-cobalt-manganese lithium positive electrode material are of high value, while the manganese is of low value. If the nickel, cobalt and lithium are selectively leached in the leaching process and the manganese is enriched in the leaching residue, the technical difficulty and cost of the subsequent extraction and separation process can be greatly reduced. The Chinese patent application number CN201210392293.3 discloses a method for separating nickel, cobalt and manganese from a high manganese-cobalt ratio nickel-cobalt-manganese raw material. The method uses a mixed solution of dilute sulfuric acid and sodium sulfite to reduce and leach nickel, cobalt and manganese, and then uses a soluble persulfate to oxidize and precipitate manganese, thereby separating manganese from the nickel and cobalt in the solution. This method first leaches manganese and then oxidizes and precipitates manganese, which consumes a large amount of reagents, a large amount of wastewater, and a complex process route. A Chinese patent with application number CN202210810317.6 discloses a method for recovering lithium, nickel, cobalt and manganese from waste ternary lithium batteries by a step-by-step leaching method. The method uses a ternary positive electrode material after reduction calcination. First, lithium is extracted by a lithium leaching agent, and nickel is extracted by a nickel leaching agent. The filter residue after nickel leaching is extracted with a manganese leaching agent, and the filter residue after manganese leaching is decarbonized by calcination to obtain cobalt-containing oxides. The technical process route of this method is complicated, the reagent consumption is large, the amount of wastewater is large, the operation is complicated, and the process cost is high. Therefore, it is necessary to develop a leaching method that selectively leaches high-value nickel, cobalt, and lithium and enriches manganese in the leached residue, so as to facilitate subsequent separation and purification, and has the advantages of low reagent consumption, small amount of wastewater, and low cost. Summary of the invention

[0005] The present invention aims to provide a step-by-step manganese leaching method for waste nickel cobalt lithium manganese oxide positive electrode materials to solve the problems of high safety risks, high reagent consumption, low production efficiency, great difficulty in subsequent treatment of the leachate and high cost in the existing leaching process of waste nickel cobalt lithium manganese oxide positive electrode materials.

[0006] In order to achieve the above object, the scheme of the present invention is: a method for step-by-step inhibition of manganese leaching of waste nickel cobalt lithium manganese oxide positive electrode material, comprising the following steps:

[0007] (1) heating a first acid leaching agent to 70-95° C., adding waste nickel cobalt lithium manganese oxide positive electrode material powder, stirring and leaching, and filtering after leaching to obtain a first filtrate and a first filter residue;

[0008] (2) heating the second acid leaching agent to 110-150° C., adding the first filter residue in step (1), adding an additive, stirring and leaching, and filtering after leaching to obtain a second filtrate and a second filter residue;

[0009] (3) The first filtrate obtained in step (1) and the second filtrate obtained in step (2) are mixed to obtain a leaching solution rich in nickel, cobalt and lithium; and manganese is enriched in the second filter residue obtained in step (2).

[0010] Optionally, in step (1), the waste nickel cobalt lithium manganese oxide positive electrode material powder is obtained by crushing, washing and drying the waste nickel cobalt lithium manganese oxide positive electrode material, and the particle size of the waste nickel cobalt lithium manganese oxide positive electrode material powder is between 30 and 150 μm.

[0011] Optionally, the particle size of the waste nickel cobalt lithium manganese oxide positive electrode material powder is between 50 and 100 μm.

[0012] Optionally, the first acid leaching agent and the second acid leaching agent are selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, citric acid, and ascorbic acid, and the additive is selected from one or more of sodium sulfite, thiourea, hydroxylamine, glucose, ascorbic acid, and ferrous sulfate.

[0013] Optionally, the concentration of the first acid leaching agent is 0.5-5 mol / L, and the concentration of the second acid leaching agent is 0.5-1 mol / L.

[0014] Optionally, in step (1), the solid-liquid ratio of the waste nickel cobalt manganese oxide positive electrode material powder to the first acid leaching agent is 60 to 200 g / L; in step (2), the solid-liquid ratio of the first filter residue to the second acid leaching agent is 40 to 200 g / L.

[0015] Optionally, in step (1), the leaching reaction time is 60 to 180 minutes, and the stirring speed is 300 to 800 rpm; in step (2), the leaching reaction time is 60 to 120 minutes, and the stirring speed is 400 to 600 rpm.

[0016] Optionally, in step (2), the amount of the additive is 5 to 25% of the mass of the first filter residue.

[0017] Optionally, in step (3), the leaching rates of nickel, cobalt and lithium in the leaching solution are 95-99.96%, and the leaching rate of manganese is below 3.35%.

[0018] The working principle and beneficial effects of this scheme are as follows: this scheme carries out a leaching process for waste nickel-cobalt-manganese-oxide lithium positive electrode material powder in two steps. In the first step, under low acid conditions, the temperature is controlled at 70-95°C to leach out all the lithium and most of the nickel and cobalt. In the second step, under low acid and a small amount of additives, the temperature is controlled at 110-150°C to leach out the remaining nickel and cobalt, and the leaching of manganese is suppressed, thereby achieving the separation of nickel-cobalt-lithium and manganese, reducing the consumption of acid and reducing agent (additive), while reducing the amount of wastewater generated and reducing the leaching cost.

[0019] Moreover, this scheme leaches nickel, cobalt, and lithium without leaching manganese, which can reduce the load of subsequent separation processes, shorten the process flow, improve separation efficiency, and reduce recovery costs. In addition, compared with the sulfuric acid + hydrogen peroxide leaching method used in industry, this scheme uses a small amount of solid additives, is safe and simple to operate, improves reagent utilization, avoids water system expansion, and improves production safety and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a schematic diagram of a process for step-by-step inhibition of manganese leaching from waste nickel-cobalt-lithium manganate positive electrode materials in Example 1 of the present invention. DETAILED DESCRIPTION

[0021] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0022] The present invention provides a method for stepwise inhibition of manganese leaching of waste nickel-cobalt-manganese-oxide lithium positive electrode material, comprising the following steps:

[0023] (1) The first acid leaching agent is heated to 70-95° C., waste nickel cobalt manganese oxide positive electrode material powder is added, stirred and leached, and filtered after leaching to obtain a first filtrate and a first filter residue. The waste nickel cobalt manganese oxide positive electrode material powder is obtained by crushing, washing and drying the waste nickel cobalt manganese oxide positive electrode material, and the particle size of the waste nickel cobalt manganese oxide positive electrode material powder is between 30 and 150 μm, preferably 50 to 100 μm; the solid-liquid ratio of the waste nickel cobalt manganese oxide positive electrode material powder to the first acid leaching agent is 60 to 200 g / L, the concentration of the first acid leaching agent is 0.5 to 5 mol / L, preferably 1.5 to 2.5 mol / L, and the first acid leaching agent is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, citric acid, and ascorbic acid; the leaching reaction time is 60 to 180 min, and the stirring speed is 300 to 800 rpm.

[0024] (2) heating the second acid leaching agent to 110-150° C., adding the first filter residue in step (1), and then adding additives, stirring and leaching, and filtering after leaching to obtain a second filtrate and a second filter residue. Wherein, the solid-liquid ratio of the first filter residue to the second acid leaching agent is 40-200 g / L, the concentration of the second acid leaching agent is 0.5-1 mol / L, the second acid leaching agent is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, citric acid, and ascorbic acid; the additive is selected from one or more of sodium sulfite, thiourea, hydroxylamine, glucose, ascorbic acid, and ferrous sulfate, and the amount of the additive is 5-25% of the mass of the first filter residue; the leaching reaction time is 60-120 min, and the stirring speed is 400-600 rpm.

[0025] (3) The first filtrate obtained in step (1) and the second filtrate obtained in step (2) are mixed to obtain a leaching solution rich in nickel, cobalt and lithium; manganese is enriched in the second filter residue obtained in step (2). The leaching rates of nickel, cobalt and lithium in the leaching solution are 95-99.99%, and the leaching rate of manganese is below 3.35%.

[0026] The following specific examples are given to illustrate the present invention in detail. It should also be understood that the following examples are only used to specifically illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention belong to the scope of protection of the present invention. The specific process parameters and the like in the following examples are also only examples within a suitable range, that is, those skilled in the art can make a selection within a suitable range according to the description herein, and are not limited to the specific values ​​​​exemplified below.

[0027] Example 1

[0028] This embodiment provides a method for step-by-step inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide lithium positive electrode materials. The process of the method is basically as follows: Figure 1 As shown, the method comprises the following steps:

[0029] (1) 100 mL of 2 mol / L sulfuric acid solution was poured into a 250 mL conical flask and heated to 70°C in a water bath; 8 g of waste nickel cobalt manganese oxide positive electrode material powder was weighed and added to the conical flask, and stirred at 700 rpm for 180 min. After leaching, the first filtrate and the first filter residue were obtained by suction filtration; the first filtrate was sent to IPC for testing and analysis. According to calculations, the leaching rates of nickel, cobalt and lithium in this process reached 76.87%, 58.29% and 98.55% respectively, while the leaching rate of manganese was only 2.24%.

[0030] (2) 20 mL of 0.5 mol / L sulfuric acid solution was measured and poured into an autoclave, the first filter residue obtained in step (1) was added into the autoclave, and then 5% (i.e. 0.05 g) of sodium sulfite by mass of the first filter residue was added, and the mixture was heated to 110° C. and stirred at 600 rpm for 120 min. After the leaching was completed, the second filtrate and the second filter residue were obtained by suction filtration; the second filtrate was sent to IPC for testing and analysis. According to calculation, the leaching rates of nickel and cobalt in this process reached 91.61% and 95.75% respectively, while the leaching rate of manganese was only 1.14%.

[0031] (3) The first filtrate obtained in step (1) and the second filtrate obtained in step (2) are mixed to obtain a leaching solution rich in nickel, cobalt and lithium; manganese is enriched in the second filter residue obtained in step (2). Comprehensive calculations show that in the whole process, the leaching rates of nickel, cobalt and lithium are 98.06%, 98.23% and 98.55% respectively, while the leaching rate of manganese is only 3.35%.

[0032] In addition, in step (1), the waste nickel cobalt manganese oxide positive electrode material powder is obtained by crushing, washing and drying the waste nickel cobalt manganese oxide positive electrode material, and the particle size of the waste nickel cobalt manganese oxide positive electrode material powder is between 50 and 100 μm, and the waste nickel cobalt manganese oxide positive electrode material powder contains Li 5.98%, Ni 38.15%, Co 9.26%, Mn 8.20%, Cu 0.06%, Fe 0.51%, Al 2.33%, Ca 0.11%, Mg 0.14%, and C 2.08%.

[0033] Example 2

[0034] This embodiment provides a method for step-by-step inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide positive electrode material. The waste nickel-cobalt-manganese-oxide positive electrode material powder involved in the method is the same as the waste nickel-cobalt-manganese-oxide positive electrode material powder in Example 1.

[0035] The method in this embodiment comprises the following steps:

[0036] (1) 100 mL of 2 mol / L sulfuric acid solution was poured into a 250 mL conical flask and heated to 75°C in a water bath; 8 g of waste nickel cobalt manganese oxide positive electrode material powder was weighed and added to the conical flask, and stirred at 700 rpm for 180 min. After leaching, the first filtrate and the first filter residue were obtained by suction filtration; the first filtrate was sent to IPC for testing and analysis. According to calculations, the leaching rates of nickel, cobalt and lithium in this process reached 80.01%, 60.02% and 99.81% respectively, while the leaching rate of manganese was only 0.24%.

[0037] (2) 20 mL of 0.5 mol / L sulfuric acid solution was measured and poured into an autoclave, the first filter residue obtained in step (1) was added into the autoclave, and then 5% (i.e. 0.05 g) of sodium sulfite by mass of the first filter residue was added, and the mixture was heated to 110° C. and stirred at 600 rpm for 120 min. After the leaching was completed, the second filtrate and the second filter residue were obtained by suction filtration; the second filtrate was sent to IPC for testing and analysis. According to calculation, the leaching rates of nickel and cobalt in this process reached 92.21% and 94.07% respectively, while the leaching rate of manganese was only 0.96%.

[0038] (3) The first filtrate obtained in step (1) and the second filtrate obtained in step (2) are mixed to obtain a leaching solution rich in nickel, cobalt and lithium; manganese is enriched in the second filter residue obtained in step (2). Comprehensive calculations show that in the whole process, the leaching rates of nickel, cobalt and lithium are 98.44%, 97.63% and 99.81% respectively, while the leaching rate of manganese is only 1.19%.

[0039] Example 3

[0040] This embodiment provides a method for step-by-step inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide positive electrode material. The waste nickel-cobalt-manganese-oxide positive electrode material powder involved in the method is the same as the waste nickel-cobalt-manganese-oxide positive electrode material powder in Example 1.

[0041] The method in this embodiment comprises the following steps:

[0042] (1) 100 mL of 2 mol / L sulfuric acid solution was poured into a 250 mL conical flask and heated to 80°C in a water bath; 8 g of waste nickel cobalt manganese oxide positive electrode material powder was weighed and added to the conical flask, and stirred at 700 rpm for 180 min. After leaching, the first filtrate and the first filter residue were obtained by suction filtration; the first filtrate was sent to IPC for testing and analysis. According to calculations, the leaching rates of nickel, cobalt and lithium in this process reached 85.85%, 61.70% and 99.96% respectively, while the leaching rate of manganese was only 0.24%.

[0043] (2) 20 mL of 0.5 mol / L sulfuric acid solution was measured and poured into an autoclave, the first filter residue obtained in step (1) was added into the autoclave, and then 10% (i.e. 0.1 g) of sodium sulfite by mass of the first filter residue was added, and the mixture was heated to 120° C. and stirred at 600 rpm for 120 min. After the leaching was completed, the second filtrate and the second filter residue were obtained by suction filtration; the second filtrate was sent to IPC for testing and analysis. According to calculation, the leaching rates of nickel and cobalt in this process reached 90.98% and 92.33% respectively, while the leaching rate of manganese was only 1.57%.

[0044] (3) The first filtrate obtained in step (1) and the second filtrate obtained in step (2) are mixed to obtain a leaching solution rich in nickel, cobalt and lithium; manganese is enriched in the second filter residue obtained in step (2). Comprehensive calculations show that in the whole process, the leaching rates of nickel, cobalt and lithium are 98.72%, 97.06% and 99.96% respectively, while the leaching rate of manganese is only 1.81%.

[0045] Example 4

[0046] This embodiment provides a method for step-by-step inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide positive electrode material. The waste nickel-cobalt-manganese-oxide positive electrode material powder involved in the method is the same as the waste nickel-cobalt-manganese-oxide positive electrode material powder in Example 1.

[0047] The method in this embodiment comprises the following steps:

[0048] (1) 100 mL of 2 mol / L sulfuric acid solution was poured into a 250 mL conical flask and heated to 85°C in a water bath; 8 g of waste nickel cobalt manganese oxide positive electrode material powder was weighed and added to the conical flask, and reacted for 180 min under stirring conditions of 700 rpm. After the leaching was completed, the first filtrate and the first filter residue were obtained by suction filtration; the first filtrate was sent to IPC for testing and analysis. According to calculations, the leaching rates of nickel, cobalt, and lithium in this process reached 82.80%, 62.23%, and 99.44%, respectively, while the leaching rate of manganese was only 0.16%.

[0049] (2) 20 mL of 0.5 mol / L sulfuric acid solution was measured and poured into an autoclave, the first filter residue obtained in step (1) was added into the autoclave, and then 15% (i.e. 0.15 g) of sodium sulfite by mass of the first filter residue was added, and the mixture was heated to 130° C. and stirred at 600 rpm for 120 min. After the leaching was completed, the second filtrate and the second filter residue were obtained by suction filtration; the second filtrate was sent to IPC for testing and analysis. According to calculation, the leaching rates of nickel and cobalt in this process reached 93.51% and 94.88% respectively, while the leaching rate of manganese was only 1.93%.

[0050] (3) The first filtrate obtained in step (1) and the second filtrate obtained in step (2) are mixed to obtain a leaching solution rich in nickel, cobalt and lithium; manganese is enriched in the second filter residue obtained in step (2). Comprehensive calculations show that in the whole process, the leaching rates of nickel, cobalt and lithium are 98.89%, 98.07% and 99.44% respectively, while the leaching rate of manganese is only 2.09%.

[0051] Example 5

[0052] This embodiment provides a method for step-by-step inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide positive electrode material. The waste nickel-cobalt-manganese-oxide positive electrode material powder involved in the method is the same as the waste nickel-cobalt-manganese-oxide positive electrode material powder in Example 1.

[0053] The method in this embodiment comprises the following steps:

[0054] (1) 100 mL of 2 mol / L sulfuric acid solution was poured into a 250 mL conical flask and heated to 90°C in a water bath; 8 g of waste nickel cobalt manganese oxide positive electrode material powder was weighed and added to the conical flask, and stirred at 700 rpm for 180 min. After leaching, the first filtrate and the first filter residue were obtained by suction filtration; the first filtrate was sent to IPC for testing and analysis. According to calculations, the leaching rates of nickel, cobalt and lithium in this process reached 86.60%, 61.73% and 99.95% respectively, while the leaching rate of manganese was only 0.32%.

[0055] (2) 20 mL of 0.5 mol / L sulfuric acid solution was measured and poured into an autoclave, the first filter residue obtained in step (1) was added into the autoclave, and then 20% (i.e. 0.2 g) of sodium sulfite by mass of the first filter residue was added, and the mixture was heated to 140° C. and stirred at 600 rpm for 120 min. After the leaching was completed, the second filtrate and the second filter residue were obtained by suction filtration; the second filtrate was sent to IPC for testing and analysis. According to calculation, the leaching rates of nickel and cobalt in this process reached 95.68% and 96.93% respectively, while the leaching rate of manganese was only 2.36%.

[0056] (3) The first filtrate obtained in step (1) and the second filtrate obtained in step (2) are mixed to obtain a leaching solution rich in nickel, cobalt and lithium; manganese is enriched in the second filter residue obtained in step (2). Comprehensive calculations show that in the whole process, the leaching rates of nickel, cobalt and lithium are 99.42%, 98.83% and 99.95% respectively, while the leaching rate of manganese is only 2.67%.

[0057] Example 6

[0058] This embodiment provides a method for step-by-step inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide positive electrode material. The waste nickel-cobalt-manganese-oxide positive electrode material powder involved in the method is the same as the waste nickel-cobalt-manganese-oxide positive electrode material powder in Example 1.

[0059] The method in this embodiment comprises the following steps:

[0060] (1) 100 mL of 2 mol / L sulfuric acid solution was poured into a 250 mL conical flask and heated to 95°C in a water bath; 8 g of waste nickel cobalt manganese oxide positive electrode material powder was weighed and added to the conical flask, and stirred at 700 rpm for 180 min. After the leaching was completed, the first filtrate and the first filter residue were obtained by suction filtration; the first filtrate was sent to IPC for testing and analysis. According to calculations, the leaching rates of nickel, cobalt and lithium in this process reached 84.89%, 63.01% and 99.17% respectively, while the leaching rate of manganese was only 0.19%.

[0061] (2) 20 mL of 0.5 mol / L sulfuric acid solution was measured and poured into an autoclave, the first filter residue obtained in step (1) was added into the autoclave, and then 25% (i.e. 0.25 g) of sodium sulfite by mass of the first filter residue was added, and the mixture was heated to 150° C. and stirred at 600 rpm for 120 min. After the leaching was completed, the second filtrate and the second filter residue were obtained by suction filtration; the second filtrate was sent to IPC for testing and analysis. According to calculation, the leaching rates of nickel and cobalt in this process reached 96.01% and 95.22% respectively, while the leaching rate of manganese was only 2.21%.

[0062] (3) The first filtrate obtained in step (1) and the second filtrate obtained in step (2) are mixed to obtain a leaching solution rich in nickel, cobalt and lithium; manganese is enriched in the second filter residue obtained in step (2). Comprehensive calculations show that in the whole process, the leaching rates of nickel, cobalt and lithium are 99.40%, 98.23% and 99.17% respectively, while the leaching rate of manganese is only 2.40%.

[0063] Comparative Example 1

[0064] This comparative example provides a method for step-by-step inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide positive electrode materials. The waste nickel-cobalt-manganese-oxide positive electrode material powder involved in the method is the same as the waste nickel-cobalt-manganese-oxide positive electrode material powder in Example 1.

[0065] The method in this comparative example comprises the following steps:

[0066] (1) Measure 100 mL of 2 mol / L sulfuric acid solution and pour it into a 250 mL conical flask, and heat it to 40°C in a water bath; weigh 8 g of waste nickel cobalt manganese oxide lithium positive electrode material powder and add it to the conical flask, and react for 180 min under stirring conditions of 700 rpm. After the leaching is completed, filter and obtain the first filtrate and the first filter residue; the first filtrate is sent to IPC for testing and analysis. According to calculations, the leaching rates of nickel, cobalt, and lithium in this process are 55.01%, 46.79%, and 89.67%, respectively, and the leaching rate of manganese is 40.70%.

[0067] (2) Measure 20 mL of 1 mol / L sulfuric acid solution and pour it into a new conical flask, heat it to 70°C in a water bath, add the first filter residue obtained in step (1) into the conical flask, and then add 5% (i.e. 0.05 g) of sodium sulfite by mass of the first filter residue, and react for 120 min under stirring at 600 rpm. After the leaching is completed, filter and obtain the second filtrate and the second filter residue; the second filtrate is sent to IPC for testing and analysis. According to calculation, the leaching rates of nickel, cobalt and lithium in this process are 94.49%, 71.03% and 99.94% respectively, and the leaching rate of manganese is 47.13%.

[0068] Comprehensive calculations show that in the entire process, the leaching rates of nickel, cobalt and lithium are 97.52%, 84.58% and 99.94% respectively, and the leaching rate of manganese is as high as 68.65%.

[0069] Comparative Example 2

[0070] This comparative example provides a method for step-by-step inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide positive electrode materials. The waste nickel-cobalt-manganese-oxide positive electrode material powder involved in the method is the same as the waste nickel-cobalt-manganese-oxide positive electrode material powder in Example 1.

[0071] The method in this comparative example comprises the following steps:

[0072] (1) Measure 100 mL of 2 mol / L sulfuric acid solution and pour it into a 250 mL conical flask, and heat it to 50°C in a water bath; weigh 8 g of waste nickel cobalt manganese oxide positive electrode material powder and add it to the conical flask, and react for 180 min under stirring conditions at 700 rpm. After the leaching is completed, filter and obtain the first filtrate and the first filter residue; the first filtrate is sent to IPC for testing and analysis. According to calculations, the leaching rates of nickel, cobalt, and lithium in this process are 63.76%, 50.96%, and 96.30%, respectively, and the leaching rate of manganese is 41.66%.

[0073] (2) 20 mL of 1 mol / L sulfuric acid solution was measured and poured into a new conical flask, heated to 70° C. in a water bath, the first filter residue obtained in step (1) was added to the conical flask, and then sodium sulfite was added in an amount of 25% (i.e., 0.25 g) of the mass of the first filter residue, and the mixture was stirred at 600 rpm for 120 min. After the leaching was completed, the second filtrate and the second filter residue were obtained by suction filtration; the second filtrate was sent to IPC for testing and analysis. According to calculation, the leaching rates of nickel, cobalt, and lithium in this process reached 98.09%, 75.05%, and 99.72%, respectively, and the leaching rate of manganese reached 73.17%.

[0074] Comprehensive calculations show that in the entire process, the leaching rates of nickel, cobalt and lithium are 99.31%, 87.76% and 99.98% respectively, and the leaching rate of manganese is as high as 84.35%.

[0075] Comparative Example 3

[0076] This comparative example provides a method for step-by-step inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide positive electrode materials. The waste nickel-cobalt-manganese-oxide positive electrode material powder involved in the method is the same as the waste nickel-cobalt-manganese-oxide positive electrode material powder in Example 1.

[0077] The method in this comparative example comprises the following steps:

[0078] (1) 100 mL of 2 mol / L sulfuric acid solution was poured into a 250 mL conical flask and heated to 60°C in a water bath; 8 g of waste nickel cobalt manganese oxide positive electrode material powder was weighed and added to the conical flask, and stirred at 700 rpm for 180 min. After the leaching was completed, the first filtrate and the first filter residue were obtained by suction filtration; the first filtrate was sent to IPC for testing and analysis. According to calculations, the leaching rates of nickel, cobalt, and lithium in this process reached 67.39%, 55.06%, and 99.51%, respectively, and the leaching rate of manganese reached 42.36%.

[0079] (2) 20 mL of 1 mol / L sulfuric acid solution was measured and poured into a new conical flask, heated to 80° C. in a water bath, the first filter residue obtained in step (1) was added to the conical flask, and then 60% (i.e. 0.60 g) of sodium sulfite by mass of the first filter residue was added, and the mixture was stirred at 600 rpm for 120 min. After the leaching was completed, the second filtrate and the second filter residue were obtained by suction filtration; the second filtrate was sent to IPC for testing and analysis. According to calculation, the leaching rates of nickel and cobalt in this process reached 99.88% and 89.90% respectively, and the leaching rate of manganese reached 98.14%.

[0080] Comprehensive calculations show that in the entire process, the leaching rates of nickel, cobalt and lithium are 99.96%, 95.46% and 99.51% respectively, while the leaching rate of manganese is as high as 98.93%.

[0081] Comparative Example 4

[0082] This comparative example provides a method for step-by-step inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide positive electrode materials. The waste nickel-cobalt-manganese-oxide positive electrode material powder involved in the method is the same as the waste nickel-cobalt-manganese-oxide positive electrode material powder in Example 1.

[0083] The method in this comparative example comprises the following steps:

[0084] (1) 100 mL of 2 mol / L sulfuric acid solution was poured into a 250 mL conical flask and heated to 60°C in a water bath; 8 g of waste nickel cobalt manganese oxide positive electrode material powder was weighed and added to the conical flask, and stirred at 700 rpm for 180 min. After the leaching was completed, the first filtrate and the first filter residue were obtained by suction filtration; the first filtrate was sent to IPC for testing and analysis. According to calculations, the leaching rates of nickel, cobalt, and lithium in this process reached 67.39%, 55.06%, and 99.51%, respectively, and the leaching rate of manganese reached 42.36%.

[0085] (2) 20 mL of 1 mol / L sulfuric acid solution was measured and poured into a new conical flask, heated to 95° C. in a water bath, the first filter residue obtained in step (1) was added to the conical flask, and then 60% (i.e. 0.60 g) of sodium sulfite by mass of the first filter residue was added, and the mixture was stirred at 600 rpm for 120 min. After the leaching was completed, the second filtrate and the second filter residue were obtained by suction filtration; the second filtrate was sent to IPC for testing and analysis. According to calculation, the leaching rates of nickel and cobalt in this process reached 99.93% and 83.72% respectively, and the leaching rate of manganese reached 52.89%.

[0086] Comprehensive calculations show that in the entire process, the leaching rates of nickel, cobalt and lithium are 99.98%, 92.68% and 99.51% respectively, while the leaching rate of manganese is as high as 72.85%.

[0087] Comparative Example 5

[0088] This comparative example provides a method for step-by-step inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide positive electrode materials. The waste nickel-cobalt-manganese-oxide positive electrode material powder involved in the method is the same as the waste nickel-cobalt-manganese-oxide positive electrode material powder in Example 1.

[0089] The method in this comparative example comprises the following steps:

[0090] (1) 100 mL of 2 mol / L sulfuric acid solution was poured into a 250 mL conical flask and heated to 65°C in a water bath; 8 g of waste nickel cobalt manganese oxide positive electrode material powder was weighed and added to the conical flask, and stirred at 700 rpm for 180 min. After leaching, the first filtrate and the first filter residue were obtained by suction filtration; the first filtrate was sent to IPC for testing and analysis. According to calculations, the leaching rates of nickel, cobalt, and lithium in this process reached 72.28%, 56.03%, and 98.97%, respectively, and the leaching rate of manganese reached 13.56%.

[0091] (2) 20 mL of 1 mol / L sulfuric acid solution was measured and poured into a new conical flask, heated to 90° C. in a water bath, the first filter residue obtained in step (1) was added to the conical flask, and then 60% (i.e. 0.60 g) of sodium sulfite by mass of the first filter residue was added, and the mixture was stirred at 600 rpm for 120 min. After the leaching was completed, the second filtrate and the second filter residue were obtained by suction filtration; the second filtrate was sent to IPC for testing and analysis. According to calculation, the leaching rates of nickel and cobalt in this process reached 98.96% and 87.28% respectively, and the leaching rate of manganese reached 53.75%.

[0092] Comprehensive calculations show that in the entire process, the leaching rates of nickel, cobalt and lithium are 99.71%, 94.41% and 98.97% respectively, while the leaching rate of manganese is as high as 60.02%.

[0093] The above are only embodiments of the present invention. The invention is not limited to the fields involved in this implementation case. The common sense such as the known specific structures and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field to which the invention belongs before the application date or the priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the present invention. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to explain the content of the claims.

Claims

1. A method for stepwise inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide lithium positive electrode materials, characterized in that: The following steps are involved: (1) heating a first acid leaching agent to 70-95° C., adding waste nickel cobalt lithium manganese oxide positive electrode material powder, stirring and leaching, and filtering after leaching to obtain a first filtrate and a first filter residue; (2) heating the second acid leaching agent to 110-150° C., adding the first filter residue in step (1), adding an additive, stirring and leaching, and filtering after leaching to obtain a second filtrate and a second filter residue; (3) mixing the first filtrate obtained in step (1) and the second filtrate obtained in step (2) to obtain a leaching solution rich in nickel, cobalt and lithium; Manganese is enriched in the second filter residue obtained in step (2).

2. The method for stepwise inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide lithium positive electrode material according to claim 1, characterized in that: In step (1), the waste nickel cobalt lithium manganese oxide positive electrode material powder is obtained by crushing, washing and drying the waste nickel cobalt lithium manganese oxide positive electrode material, and the particle size of the waste nickel cobalt lithium manganese oxide positive electrode material powder is between 30 and 150 μm.

3. The method for stepwise inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide lithium positive electrode material according to claim 2, characterized in that: The particle size of the waste nickel-cobalt-lithium manganese oxide positive electrode material powder is between 50 and 100 μm.

4. The method for stepwise inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide lithium positive electrode material according to claim 1, characterized in that: The first acid leaching agent and the second acid leaching agent are selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, citric acid, and ascorbic acid, and the additive is selected from one or more of sodium sulfite, thiourea, hydroxylamine, glucose, ascorbic acid, and ferrous sulfate.

5. The method for stepwise inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide lithium positive electrode material according to claim 1, characterized in that: The concentration of the first acid leaching agent is 0.5-5 mol / L, and the concentration of the second acid leaching agent is 0.5-1 mol / L.

6. The method for stepwise inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide lithium positive electrode material according to claim 1, characterized in that: In step (1), the solid-liquid ratio of the waste nickel cobalt manganese oxide positive electrode material powder to the first acid leaching agent is 60 to 200 g / L; in step (2), the solid-liquid ratio of the first filter residue to the second acid leaching agent is 40 to 200 g / L.

7. The method for stepwise inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide lithium positive electrode material according to claim 1, characterized in that: In step (1), the leaching reaction time is 60 to 180 minutes, and the stirring speed is 300 to 800 rpm; in step (2), the leaching reaction time is 60 to 120 minutes, and the stirring speed is 400 to 600 rpm.

8. The method for stepwise inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide lithium positive electrode material according to claim 1, characterized in that: In step (2), the amount of the additive is 5 to 25% of the mass of the first filter residue.

9. The method for stepwise inhibition of manganese leaching from waste nickel-cobalt-manganese-oxide lithium positive electrode material according to claim 1, characterized in that: In step (3), the leaching rates of nickel, cobalt and lithium in the leaching solution are 95-99.96%, and the leaching rate of manganese is below 3.35%.

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