A method for recovering manganese dioxide from a nickel-cobalt-manganese mixture

Abstract

The application provides a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture, which comprises the following steps: adding water to the nickel-cobalt-manganese mixture to perform slurry, performing leaching reaction in an acid condition and an oxidizing agent, and performing solid-liquid separation to obtain leaching solution and leaching residue; the leaching solution is used for recovering nickel and cobalt; the leaching residue is sequentially subjected to acid washing, water washing and drying to recover manganese dioxide. The method adopts a selective manganese precipitation method, by using a suitable oxidizing agent and controlling parameters such as oxidizing agent addition amount and pH value, manganese in the nickel-cobalt-manganese mixture is directly selectively precipitated in the leaching process and is inhibited in the leaching residue, nickel and cobalt are recovered from the leaching solution, and manganese dioxide is recovered from the leaching residue. Through the method, the recovery rate of manganese can reach more than 95%, the purity of manganese dioxide can reach more than 90%, and the leaching rates of cobalt and nickel in the nickel-cobalt-manganese mixture are both more than 95%.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture. Background Art

[0002] Manganese nickel cobalt hydroxide (MHP) is typically produced from laterite nickel ore through high-pressure acid leaching (HPAL). MHP is a nickel intermediate used to make nickel sulfate. As a key element in ternary battery cathode materials, coupled with the continued development of high-nickel batteries, nickel sulfate has a significant future market potential, driving demand for MHP raw materials.

[0003] MHP raw materials are also known as nickel-cobalt-manganese mixed raw materials. Depending on production needs, manganese recovery from this mixed raw material is often required. Currently, manganese recovery from this mixed raw material typically involves leaching and extraction, where manganese is recovered as manganese sulfate. This method is complex, lengthy, and consumes a large amount of auxiliary materials. Some researchers have also attempted to recover manganese as manganese dioxide, but these typically involve electrolysis or extraction to separate and enrich the manganese, followed by precipitation. This process is lengthy and results in low manganese recovery rates.

[0004] For example, CN115478180A discloses a method for recovering manganese dioxide from a ternary material cathode powder, comprising the following steps: mixing the ternary material cathode powder with water to obtain a slurry A; then adding concentrated sulfuric acid and hydrogen peroxide to the slurry A to leach a nickel-cobalt-manganese mixed solution, filtering to obtain a leachate B; extracting the leachate B with an organic extractant to obtain a loaded organic phase C and a residual aqueous phase D; washing and stripping the loaded organic phase C with dilute sulfuric acid to obtain a stripping solution E; adjusting the pH value of the stripping solution E to above 4 with a neutralizing agent, and separating to obtain a filtrate F; adding a sulfide to the filtrate F to adjust the pH to above 5, and separating to obtain a filtrate I; adding an alkali solution and an oxidant to the filtrate I, adjusting the pH to above 9, forming a manganese dioxide precipitate, and separating and recovering. However, this recovery method belongs to a leaching-extraction method, in which the manganese element is first recovered in the form of manganese sulfate, and then a manganese dioxide precipitate is obtained by an alkali solution and an oxidant. The process is complex, the process is long, and the auxiliary material consumption is high, which is not suitable for promotion and use.

[0005] In summary, it is necessary to develop a method for recovering manganese dioxide from nickel-cobalt-manganese mixture. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture. The method comprises adding water to the nickel-cobalt-manganese mixture for slurrying, carrying out a leaching reaction under acidic conditions and an oxidant, and obtaining a leachate and a leach residue through solid-liquid separation; the leachate is used to recover nickel and cobalt; the leach residue is sequentially pickled, washed with water, and dried to recover manganese dioxide. The method of the present invention adopts a selective manganese precipitation method. By using a suitable oxidant and controlling parameters such as the amount of the oxidant added and the pH value, manganese in the nickel-cobalt-manganese mixture is selectively precipitated and suppressed in the leach residue during the leaching process, nickel and cobalt are recovered from the leachate, and manganese dioxide is recovered from the leach residue. By using the method of the present invention, the recovery rate of manganese can reach more than 95%, the purity of manganese dioxide can reach more than 90%, and the leaching rates of cobalt and nickel in the nickel-cobalt-manganese mixture are both more than 95%. Moreover, the method of the present invention has the characteristics of simple process, short flow, high recovery rate, low cost, and high purity of manganese dioxide product.

[0007] The object of the present invention is to provide a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture, the method comprising the steps of:

[0008] (1) adding water to the nickel-cobalt-manganese mixture to form a slurry, and performing a leaching reaction in an acidic condition and an oxidant to obtain a leaching reaction slurry;

[0009] (2) subjecting the leaching reaction slurry of step (1) to solid-liquid separation to obtain leachate and leach residue;

[0010] (3) using the leachate from step (2) to recover nickel and cobalt;

[0011] (4) sequentially pickling, washing with water and drying the leached residue in step (2) to recover manganese dioxide;

[0012] There is no order between steps (3) and (4).

[0013] The method of the present invention adopts a selective manganese precipitation method. By using a suitable oxidant and controlling parameters such as the amount of the oxidant added and the pH value, manganese in the nickel-cobalt-manganese mixture is selectively precipitated and suppressed in the leaching residue during the leaching process, nickel and cobalt are recovered from the leachate, and manganese dioxide is recovered from the leaching residue. Through the method of the present invention, the recovery rate of manganese can reach more than 95%, the purity of manganese dioxide can reach more than 90%, and the leaching rates of cobalt and nickel in the nickel-cobalt-manganese mixture are both above 95%. Moreover, the method of the present invention has the characteristics of simple process, short flow, high recovery rate, low cost, and high purity of manganese dioxide product.

[0014] As a preferred technical solution of the present invention, the nickel-cobalt-manganese mixture in step (1) is nickel-cobalt-manganese hydroxide, wherein the Mn content is 3-10wt%, for example, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0015] It is worth noting that the nickel-cobalt-manganese mixture of the present invention is not limited to the material obtained by acid leaching of laterite nickel ore, but can also be the recycled material of the positive electrode powder of waste battery ternary materials, as long as the nickel-cobalt-manganese mixture is nickel-cobalt-manganese hydroxide.

[0016] As a preferred technical solution of the present invention, the step (1) of adding water for slurrying controls the slurry solid-liquid ratio to be 1:(2-6), such as 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5 or 1:6, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0017] Preferably, the pH value of the acidic condition in step (1) is 0.5-1.5, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4 or 1.5, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0018] Preferably, the acidic condition in step (1) uses sulfuric acid as the acid agent.

[0019] It is worth noting that the leaching reaction of the present invention uses sulfuric acid as an acid agent to provide the required acidic conditions, but there is no restriction on the concentration of sulfuric acid, as long as the pH can be adjusted and controlled; moreover, since hydrochloric acid is volatile, has a strong odor, and severely corrodes equipment, it is not recommended for use in actual production. Nitric acid is relatively expensive and is rarely used in industry.

[0020] As a preferred technical solution of the present invention, the oxidant in step (1) comprises any one of sodium persulfate, potassium persulfate and ammonium persulfate, or a combination of at least two thereof. Typical but non-limiting examples of the combination include: a combination of sodium persulfate and potassium persulfate, a combination of potassium persulfate and ammonium persulfate, or a combination of sodium persulfate and ammonium persulfate.

[0021] Preferably, the mass ratio of the amount of the oxidant added in step (1) to the Mn element in the nickel-cobalt-manganese mixture is (2-3):1, for example, 2:1, 2.1:1, 2.3:1, 2.5:1, 2.6:1, 2.8:1 or 3:1, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0022] As a preferred technical solution of the present invention, the reaction temperature of the leaching reaction in step (1) is 40-100°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0023] Preferably, the reaction time of the leaching reaction in step (1) is 1-4 h, for example, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h or 4 h, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0024] As a preferred technical solution of the present invention, step (3) also includes sequentially removing impurities and extracting and separating the leaching solution of step (2) to recover nickel and cobalt.

[0025] It is worth noting that the impurity removal and extraction separation described in the present invention are conventional technical means in the prior art and will not be described in detail here.

[0026] As a preferred technical solution of the present invention, sulfuric acid is used as the pickling agent in step (4).

[0027] It is worth noting that the pickling method described in the present invention uses sulfuric acid as the pickling agent, but there is no restriction on the concentration of sulfuric acid, as long as the pH can be adjusted and controlled; moreover, since hydrochloric acid is volatile, has a strong odor, and severely corrodes equipment, it is not recommended for use in actual production. Nitric acid is relatively expensive and is rarely used in industry.

[0028] Preferably, the pH value of the pickling reaction system in step (4) is controlled to be between 1.0 and 2.0.

[0029] Preferably, the pickling temperature in step (4) is 40-100°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0030] Preferably, the pickling time in step (4) is 1-4 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, etc., but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0031] Preferably, the pickling liquid obtained by pickling in step (4) is returned to step (1) as slurry bottom water.

[0032] As a preferred technical solution of the present invention, the water washing in step (4) adopts a multi-stage countercurrent washing method, and the goal of the water washing is to wash until the filtrate is neutral.

[0033] Preferably, the water washing temperature in step (4) is 40-100°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0034] Preferably, the water washing time in step (4) is 1-2 h, for example, 1 h, 1.1 h, 1.3 h, 1.5 h, 1.7 h, 1.8 h or 2 h, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0035] Preferably, the washing liquid obtained in the water washing in step (4) is collected and returned to the acid washing in step (4) as acid washing bottom water.

[0036] As a preferred technical solution of the present invention, the drying temperature in step (4) is 100-120°C, for example, 100°C, 102°C, 105°C, 107°C, 110°C, 113°C, 115°C, 118°C or 120°C, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0037] As a preferred technical solution of the present invention, the method comprises the following steps:

[0038] (1) adding water to a nickel-cobalt-manganese mixture for slurrying, and performing a leaching reaction at 40-100° C. for 1-4 hours in an acidic condition and an oxidant to obtain a leaching reaction slurry; wherein the nickel-cobalt-manganese mixture is nickel-cobalt-manganese hydroxide, wherein the Mn content is 3-10 wt%; the slurrying is performed by controlling the solid-liquid ratio of the slurry to be 1:(2-6); sulfuric acid is used as an acid agent in the acidic condition to control the pH value to be 0.5-1.5; the oxidant includes any one of sodium persulfate, potassium persulfate and ammonium persulfate or a combination of at least two thereof; the mass ratio of the added amount of the oxidant to the Mn element in the nickel-cobalt-manganese mixture is (2-3):1;

[0039] (2) subjecting the leaching reaction slurry of step (1) to solid-liquid separation to obtain leachate and leach residue;

[0040] (3) The leachate of step (2) is subjected to impurity removal and extraction separation in sequence to recover nickel and cobalt

[0041] (4) The leached residue of step (2) is pickled, washed and dried in sequence to recover manganese dioxide; wherein, sulfuric acid is used as a pickling agent for pickling; the pH value of the pickling control system is 1.0-2.0; the temperature of the pickling is 40-100°C; the pickling time is 1-4 hours; the pickling liquid obtained by the pickling is returned to step (1) as pulping bottom water; the water washing adopts a multi-stage countercurrent washing method, and the goal of the water washing is to wash until the filtrate is neutral; the water washing temperature is 40-100°C; the water washing time is 1-2 hours; the water washing liquid obtained by the water washing is collected and returned to the pickling as pickling bottom water; the drying temperature is 100-120°C;

[0042] There is no order between steps (3) and (4).

[0043] Compared with the existing technical solutions, the present invention has at least the following beneficial effects:

[0044] (1) The method of the present invention adopts a selective manganese precipitation method. By using a suitable oxidant and controlling the parameters, the manganese in the nickel-cobalt-manganese mixture is directly selectively precipitated during the leaching process and suppressed in the leaching residue. Nickel and cobalt are recovered from the leachate, and manganese dioxide is recovered from the leaching residue. Through the method of the present invention, the manganese recovery rate can reach more than 95%, the purity of manganese dioxide can reach more than 90%, and the leaching rates of cobalt and nickel in the nickel-cobalt-manganese mixture are both above 95%;

[0045] (2) The method of the present invention has the characteristics of simple process, short flow, high recovery rate, low cost and high purity of manganese dioxide product. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The present invention is a process flow chart of the method for recovering manganese dioxide from a nickel-cobalt-manganese mixture. DETAILED DESCRIPTION

[0047] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0048] The present invention provides a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture, and the process flow chart thereof is as follows: Figure 1 As shown, the method includes the following steps:

[0049] (1) adding water to the nickel-cobalt-manganese mixture to form a slurry, adding sulfuric acid and an oxidant to carry out a leaching reaction, and obtaining a leaching reaction slurry;

[0050] (2) subjecting the leaching reaction slurry of step (1) to solid-liquid separation to obtain leachate and leach residue;

[0051] (3) using the leachate from step (2) to recover nickel and cobalt;

[0052] (4) The leached residue of step (2) is sequentially pickled, washed with water, and dried to recover manganese dioxide; the pickling liquid obtained by pickling is returned to step (1) as pulping bottom water; the washing liquid obtained by washing with water is collected and returned to the pickling process as pickling bottom water;

[0053] There is no order between steps (3) and (4).

[0054] To better illustrate the present invention and facilitate understanding of the technical solutions of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0055] Example 1

[0056] This embodiment provides a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture, the method comprising the following steps:

[0057] (1) adding water to a nickel-cobalt-manganese mixture for slurrying, and performing a leaching reaction at 70° C. for 2 hours in an acidic condition and an oxidant to obtain a leaching reaction slurry; wherein the nickel-cobalt-manganese mixture is nickel-cobalt-manganese hydroxide, wherein the Mn content is 7 wt%; the slurrying is controlled to have a solid-liquid ratio of 1:3 by adding water; sulfuric acid is used as an acid agent in the acidic condition to control the pH value to 0.5; the oxidant is sodium persulfate; and the mass ratio of the added amount of the oxidant to the Mn element in the nickel-cobalt-manganese mixture is 2.5:1;

[0058] (2) subjecting the leaching reaction slurry of step (1) to solid-liquid separation to obtain leachate and leach residue;

[0059] (3) The leachate of step (2) is subjected to impurity removal and extraction separation in sequence to recover nickel and cobalt

[0060] (4) The leaching residue of step (2) is sequentially pickled, washed and dried to recover manganese dioxide; wherein, sulfuric acid is used as a pickling agent for pickling; the pH value of the pickling control system is 1.5; the temperature of the pickling is 70°C; the pickling time is 3 hours; the pickling liquid obtained by the pickling is returned to step (1) as pulping bottom water; the water washing adopts a multi-stage countercurrent washing method, and the goal of the water washing is to wash until the filtrate is neutral; the water washing temperature is 70°C; the water washing time is 1.5 hours; the water washing liquid obtained by the water washing is collected and returned to the pickling as pickling bottom water; the drying temperature is 110°C;

[0061] There is no order between steps (3) and (4).

[0062] Example 2

[0063] This embodiment provides a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture, the method comprising the following steps:

[0064] (1) adding water to a nickel-cobalt-manganese mixture for slurrying, and performing a leaching reaction at 60° C. for 3 hours in an acidic condition and an oxidant to obtain a leaching reaction slurry; wherein the nickel-cobalt-manganese mixture is nickel-cobalt-manganese hydroxide, wherein the Mn content is 8 wt%; the slurrying is controlled to have a solid-liquid ratio of 1:4 by adding water; sulfuric acid is used as an acid agent in the acidic condition to control the pH value to be 1.0; the oxidant is potassium persulfate; and the mass ratio of the added amount of the oxidant to the Mn element in the nickel-cobalt-manganese mixture is 2.2:1;

[0065] (2) subjecting the leaching reaction slurry of step (1) to solid-liquid separation to obtain leachate and leach residue;

[0066] (3) The leachate of step (2) is subjected to impurity removal and extraction separation in sequence to recover nickel and cobalt

[0067] (4) The leaching residue of step (2) is sequentially pickled, washed and dried to recover manganese dioxide; wherein, sulfuric acid is used as a pickling agent for pickling; the pH value of the pickling control system is 1.0; the temperature of the pickling is 50°C; the pickling time is 3 hours; the pickling liquid obtained by the pickling is returned to step (1) as pulping bottom water; the water washing adopts a multi-stage countercurrent washing method, and the goal of the water washing is to wash until the filtrate is neutral; the water washing temperature is 40°C; the water washing time is 2 hours; the water washing liquid obtained by the water washing is collected and returned to the pickling as pickling bottom water; the drying temperature is 120°C;

[0068] There is no order between step (3) and step (4).

[0069] Example 3

[0070] This embodiment provides a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture, the method comprising the following steps:

[0071] (1) adding water to a nickel-cobalt-manganese mixture for slurrying, and performing a leaching reaction at 90° C. for 1 hour in an acidic condition and an oxidant to obtain a leaching reaction slurry; wherein the nickel-cobalt-manganese mixture is nickel-cobalt-manganese hydroxide, wherein the Mn content is 4 wt%; the slurrying is performed by controlling the solid-liquid ratio of the slurry to be 1:5; sulfuric acid is used as an acid agent in the acidic condition to control the pH value to be 1.5; the oxidant is ammonium persulfate; and the mass ratio of the added amount of the oxidant to the Mn element in the nickel-cobalt-manganese mixture is 2.0:1;

[0072] (2) subjecting the leaching reaction slurry of step (1) to solid-liquid separation to obtain leachate and leach residue;

[0073] (3) The leachate of step (2) is subjected to impurity removal and extraction separation in sequence to recover nickel and cobalt

[0074] (4) The leached residue of step (2) is pickled, washed and dried in sequence to recover manganese dioxide; wherein, sulfuric acid is used as a pickling agent for pickling; the pH value of the pickling control system is 2.0; the temperature of the pickling is 90°C; the pickling time is 4 hours; the pickling liquid obtained by the pickling is returned to step (1) as pulping bottom water; the water washing adopts a multi-stage countercurrent washing method, and the goal of the water washing is to wash until the filtrate is neutral; the water washing temperature is 90°C; the water washing time is 1 hour; the water washing liquid obtained by the water washing is collected and returned to the pickling as pickling bottom water; the drying temperature is 100°C;

[0075] There is no order between step (3) and step (4).

[0076] Comparative Example 1

[0077] This comparative example provides a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture. Compared with the method described in Example 1, the only difference is that the leaching reaction in step (1) is not carried out under acidic conditions, that is, after the nickel-cobalt-manganese mixture is slurried with water, an oxidant is directly added to carry out the leaching reaction.

[0078] Comparative Example 2

[0079] This comparative example provides a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture. Compared with the method described in Example 1, the only difference is that sodium hypochlorite is used as an oxidant in step (1).

[0080] Comparative Example 3

[0081] This comparative example provides a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture. Compared with the method described in Example 1, the only difference is that the mass ratio of the added amount of the oxidant in step (1) to the Mn element in the nickel-cobalt-manganese mixture is 1:1.

[0082] Comparative Example 4

[0083] This comparative example provides a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture. Compared with the method described in Example 1, the only difference is that the mass ratio of the added amount of the oxidant to the Mn element in the nickel-cobalt-manganese mixture in step (1) is 4:1.

[0084] Comparative Example 5

[0085] This comparative example provides a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture. Compared with the method described in Example 1, the only difference is that sulfuric acid is used as the acid agent in the acidic condition in step (1) and the pH value is controlled to be 0.2.

[0086] Comparative Example 6

[0087] This comparative example provides a method for recovering manganese dioxide from a nickel-cobalt-manganese mixture. Compared with the method described in Example 1, the only difference is that sulfuric acid is used as the acid agent in the acidic condition in step (1) and the pH value is controlled to be 2.

[0088] The methods described in the above examples and comparative examples were used to characterize the recovery rate of manganese, the purity of manganese dioxide, and the leaching rates of cobalt and nickel in the nickel-cobalt-manganese mixture. The specific characterization results are shown in Table 1.

[0089] Table 1

[0090] project Manganese recovery rate Purity of manganese dioxide Leaching rates of cobalt and nickel from nickel-cobalt-manganese mixture Example 1 97％ 95％ Co=97%,Ni=98% Example 2 96％ 92％ Co=96%,Ni=99% Example 3 95.5％ 91％ Co=95.5%,Ni=98% Comparative Example 1 99％ 11％ Co=2%,Ni=4% Comparative Example 2 50％ 70％ Co=98%,Ni=99% Comparative Example 3 80％ 90％ Co=98%,Ni=99% Comparative Example 4 99.5％ 75％ Co=62%,Ni=95% Comparative Example 5 92％ 95％ Co=98.5%,Ni=99.5% Comparative Example 6 98％ 84％ Co=85%,Ni=95%

[0091] The following points can be seen from Table 1:

[0092] (1) Examples 1-3 of the present invention adopt a selective manganese precipitation method. By using a suitable oxidant and controlling the parameters, the manganese in the nickel-cobalt-manganese mixture is directly selectively precipitated during the leaching process and suppressed in the leaching residue. Nickel and cobalt are recovered from the leachate, and manganese dioxide is recovered from the leaching residue. By using the method of the present invention, the recovery rate of manganese can reach more than 95%, the purity of manganese dioxide can reach more than 90%, and the leaching rates of cobalt and nickel in the nickel-cobalt-manganese mixture are both above 95%.

[0093] (2) Comparing Comparative Example 1 with Example 1, since the leaching reaction in step (1) of Comparative Example 1 was not carried out under acidic conditions, most of the cobalt, nickel, and manganese in the nickel-cobalt-manganese mixture were not leached but remained in the leaching residue, resulting in a manganese dioxide purity of only 11%, a cobalt leaching rate of only 2%, and a nickel leaching rate of only 4% in the nickel-cobalt-manganese mixture;

[0094] (3) Comparing Comparative Example 2 with Example 1, since sodium hypochlorite was used as the oxidant in Comparative Example 2, part of the manganese in the nickel-cobalt-manganese mixture was leached into the leachate, resulting in a decrease in the manganese remaining in the leaching residue. The manganese recovery rate was only 50%, and the purity of the manganese dioxide was only 70%.

[0095] (4) Comparing Comparative Examples 3 and 4 with Example 1, since the mass ratio of the amount of the added oxidant to the Mn element in the nickel-cobalt-manganese mixture in Comparative Example 3 is lower than (2-3):1, the manganese recovery rate is only 80%. Since the mass ratio of the amount of the added oxidant to the Mn element in the nickel-cobalt-manganese mixture in Comparative Example 3 is higher than (2-3):1, the purity of the manganese dioxide is only 75%.

[0096] (5) Comparing Comparative Examples 5 and 6 with Example 1, since the acidic conditions described in Comparative Example 5 use sulfuric acid as the acid agent and the pH value is controlled to be 0.2, which is lower than the pH value of 0.5-1.5 described in the present invention, the manganese recovery rate is low and sulfuric acid resources are wasted. Since the acidic conditions described in Comparative Example 6 use sulfuric acid as the acid agent and the pH value is controlled to be 2, which is higher than the pH value of 0.5-1.5 described in the present invention, the leaching of cobalt and nickel in the cobalt-nickel-manganese mixture is insufficient, and a small amount of cobalt and nickel remain in the leaching residue, thereby reducing the purity of manganese dioxide, making the purity of manganese dioxide only 84%.

[0097] While the present invention is described through the above-described embodiments to illustrate the detailed structural features of the present invention, the present invention is not limited to these detailed structural features, nor does it necessarily rely on these detailed structural features for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for selected components, additions of auxiliary components, and selection of specific embodiments, etc., fall within the scope of protection and disclosure of the present invention.

[0098] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0099] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0100] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for recovering manganese dioxide from a nickel-cobalt-manganese mixture, characterized in that: The method comprises the following steps: (1) adding water to the nickel-cobalt-manganese mixture to form a slurry, and performing a leaching reaction in an acidic condition and an oxidant to obtain a leaching reaction slurry; (2) subjecting the leaching reaction slurry of step (1) to solid-liquid separation to obtain leachate and leach residue; (3) using the leachate from step (2) to recover nickel and cobalt; (4) sequentially pickling, washing with water and drying the leached residue in step (2) to recover manganese dioxide; Among them, step (3) and step (4) have no order; The pH value of the acidic condition in step (1) is 0.5-1.5; sulfuric acid is used as the acid agent in the acidic condition in step (1).

2. The method according to claim 1, characterized in that The nickel-cobalt-manganese mixture in step (1) is nickel-cobalt-manganese hydroxide, wherein the Mn content is 3-10wt%.

3. The method according to claim 1, characterized in that In step (1), water is added to slurry to control the slurry solid-liquid ratio to be 1:(2-6).

4. The method according to claim 1, wherein The oxidant in step (1) includes any one of sodium persulfate, potassium persulfate and ammonium persulfate, or a combination of at least two of them.

5. The method according to claim 1, wherein The mass ratio of the amount of the oxidant added in step (1) to the Mn element in the nickel-cobalt-manganese mixture is (2-3):

1.

6. The method according to claim 1, characterized in that The reaction temperature of the leaching reaction in step (1) is 40-100°C.

7. The method according to claim 1, characterized in that The reaction time of the leaching reaction in step (1) is 1-4 hours.

8. The method according to claim 1, characterized in that Step (3) also includes sequentially removing impurities and extracting and separating the leaching solution of step (2) to recover nickel and cobalt.

9. The method according to claim 1, characterized in that The pickling in step (4) uses sulfuric acid as the pickling agent.

10. The method according to claim 1, characterized in that The pH value of the pickling control system in step (4) is 1.0-2.

0.

11. The method according to claim 1, wherein The pickling temperature in step (4) is 40-100°C.

12. The method according to claim 1, characterized in that The pickling time in step (4) is 1-4 hours.

13. The method according to claim 1, wherein The pickling liquid obtained by pickling in step (4) is returned to step (1) as pulping bottom water.

14. The method according to claim 1, wherein The water washing in step (4) adopts a multi-stage countercurrent washing method, and the goal of the water washing is to wash until the filtrate is neutral.

15. The method according to claim 1, wherein The water washing temperature in step (4) is 40-100°C.

16. The method according to claim 1, wherein The washing time in step (4) is 1-2 hours.

17. The method according to claim 1, wherein The washing liquid obtained in step (4) is collected and returned to the acid washing in step (4) as acid washing bottom water.

18. The method according to any one of claims 1 to 17, characterized in that The drying temperature in step (4) is 100-120°C.

19. The method according to claim 1, wherein The method comprises the following steps: (1) adding water to a nickel-cobalt-manganese mixture for slurrying, and performing a leaching reaction at 40-100° C. for 1-4 hours in an acidic condition and an oxidant to obtain a leaching reaction slurry; wherein the nickel-cobalt-manganese mixture is nickel-cobalt-manganese hydroxide, wherein the Mn content is 3-10 wt%; the slurrying is performed by controlling the solid-liquid ratio of the slurry to be 1:(2-6); sulfuric acid is used as an acid agent in the acidic condition to control the pH value to be 0.5-1.5; the oxidant includes any one of sodium persulfate, potassium persulfate and ammonium persulfate or a combination of at least two thereof; the mass ratio of the added amount of the oxidant to the Mn element in the nickel-cobalt-manganese mixture is (2-3):1; (2) subjecting the leaching reaction slurry of step (1) to solid-liquid separation to obtain leachate and leach residue; (3) The leachate of step (2) is subjected to impurity removal and extraction separation in sequence to recover nickel and cobalt (4) The leached residue of step (2) is pickled, washed and dried in sequence to recover manganese dioxide; wherein, sulfuric acid is used as a pickling agent for pickling; the pH value of the pickling control system is 1.0-2.0; the temperature of the pickling is 40-100°C; the pickling time is 1-4 hours; the pickling liquid obtained by the pickling is returned to step (1) as pulping bottom water; the water washing adopts a multi-stage countercurrent washing method, and the goal of the water washing is to wash until the filtrate is neutral; the water washing temperature is 40-100°C; the water washing time is 1-2 hours; the water washing liquid obtained by the water washing is collected and returned to the pickling as pickling bottom water; the drying temperature is 100-120°C; There is no order between steps (3) and (4).

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