A method for preparing a battery-grade nickel cobalt manganese sulfate solution from low-ice nickel

Abstract

This invention discloses a method for preparing battery-grade nickel-cobalt-manganese sulfate solution from low-grade nickel matte. Low-grade nickel matte is ground and then leached with concentrated sulfuric acid under normal pressure to obtain a first slag phase and a first liquid phase. The first liquid phase is evaporated, concentrated, and then cooled to crystallize, yielding ferrous sulfate crystals. Concentrated sulfuric acid is added to the first slag phase, and oxygen pressure leaching is performed to obtain a second slag phase and a second liquid phase. The pH of the second liquid phase is adjusted to 3-4 to generate a precipitate. The precipitate is filtered off to obtain a filtrate. The filtrate is then adsorbed using a chelating resin. The adsorbed chelating resin is first washed with a first sulfuric acid solution to obtain a washing solution containing Mg and Mn, and then washed with a second sulfuric acid solution to obtain a nickel-cobalt sulfate solution. The nickel-cobalt sulfate solution is mixed with the washing solution containing Mg and Mn to obtain a nickel-cobalt-manganese sulfate solution. This invention uses low-grade nickel matte as a raw material to prepare battery-grade nickel-cobalt sulfate solution, improving the recovery rate of nickel and cobalt and reducing acid consumption.

Description

Technical Field

[0001] This invention belongs to the field of metallurgy, and particularly relates to a method for preparing battery-grade nickel cobalt manganese sulfate solution with low nickel matte content. Background Technology

[0002] Nickel sulfate is mainly divided into battery-grade nickel sulfate and electroplating-grade nickel sulfate. Battery-grade nickel sulfate is the main source of nickel metal in ternary materials, used to prepare lithium nickel cobalt manganese oxide (NCM) and lithium nickel cobalt aluminum oxide (NCA). Since the nickel content of ternary lithium batteries directly determines the battery's capacity, the development of high-nickel ternary lithium batteries is an inevitable trend and will become the second largest consumer of nickel. The demand for electroplating-grade nickel sulfate is relatively stable and it is widely used in the manufacturing industries of machinery, instruments, meters, medical devices, and household appliances.

[0003] Laterite nickel ore has gradually become a major source of nickel metal, with pyrometallurgical processes being widely adopted due to their simplicity and short process flow. The process of "latite nickel ore - electric furnace smelting (sulfidation) - low-grade matte - converter blowing - high-grade matte" is used by smelters such as Tsingshan and Sorowako. This involves drying and pre-reducing the laterite nickel ore in a rotary kiln, then smelting it in an electric furnace while adding a sulfiding agent to obtain low-grade matte (approximately 20% Ni and 65% iron), followed by blowing in a PS converter to produce high-grade matte (approximately 60% Ni and 5% iron). While the nickel content increases during the blowing process from low-grade to high-grade matte, it leads to the loss of nickel and cobalt, resulting in resource waste and high energy consumption. Therefore, a method that directly selectively leaches nickel and cobalt from low-grade matte would not only shorten the process flow but also reduce the loss of nickel and cobalt. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing battery-grade nickel cobalt manganese sulfate solution using low-grade nickel matte.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for preparing battery-grade nickel-cobalt-manganese sulfate solution using low-grade nickel matte comprises the following steps:

[0007] (1) After grinding low-grade nickel matte, concentrated sulfuric acid is added and leaching is carried out under normal pressure to obtain a first slag phase and a first liquid phase. The first liquid phase is evaporated, concentrated, cooled, and crystallized to obtain ferrous sulfate crystals. Concentrated sulfuric acid is added to the first slag phase and oxygen pressure leaching is carried out.

[0008] The purpose of oxygen pressure leaching is to dissolve Fe in nickel matte with sulfuric acid to generate Fe. 2+ Oxidation to Fe by oxygen 3+The mixture is then hydrolyzed to Fe2O3 under high temperature and pressure, selectively leaching nickel and cobalt from the low-grade nickel matte. After high-pressure filtration, the slag phase is discharged into the tailings pond, or the iron in it can be recovered.

[0009] (2) After oxygen pressure leaching in step (1), a second slag phase and a second liquid phase are obtained. The pH of the second liquid phase is adjusted to 3-4 to generate a precipitate. The precipitate is filtered out to obtain a filtrate. The filtrate is adsorbed by chelating resin. The chelating resin after adsorption is first washed with a first sulfuric acid solution to obtain a washing solution containing Mg and Mn, and then washed with a second sulfuric acid solution to obtain a nickel-cobalt sulfate solution.

[0010] (3) Mix the nickel cobalt sulfate solution described in step (2) with a washing solution containing Mg and Mn to prepare a nickel cobalt manganese sulfate solution.

[0011] Preferably, after grinding the low-grade nickel matte in step (1), concentrated sulfuric acid is added, and the mass ratio of concentrated sulfuric acid to low-grade nickel matte is 0.1 to 0.5:1.

[0012] Preferably, in step (1), concentrated sulfuric acid is added to the first slag phase, and the mass ratio of concentrated sulfuric acid to the first slag phase is 0 to 0.25:1.

[0013] Preferably, the oxygen pressure leaching conditions in step (1) are: temperature of 180-220℃, oxygen partial pressure of 10-30%, pressure of 2.5-3.5MPa, and leaching time of 4-8h.

[0014] Preferably, the concentration of the concentrated sulfuric acid in step (1) is 98 wt%;

[0015] Preferably, the particle size after grinding the low-nickel matte in step (1) is 50-200 mesh;

[0016] Preferably, the atmospheric pressure leaching time in step (1) is 1 to 4 hours.

[0017] Preferably, in step (2), the concentration of the first sulfuric acid solution is 0.5% to 3%.

[0018] Preferably, the concentration of the second sulfuric acid solution in step (2) is 8-13 wt%.

[0019] Preferably, step (2) involves adjusting the pH of the second liquid phase by adding limestone.

[0020] Preferably, the chelating resin in step (2) is IRC 748 chelating resin.

[0021] Preferably, the method of using chelating resin to adsorb the filtrate in step (2) is as follows: at pH = 2 to 4, the chelating resin dynamically adsorbs nickel and cobalt in the filtrate in the resin column, the amount of chelating resin is 30g, the dynamic adsorption of 400 to 500mL of filtrate is 10 to 20min.

[0022] Preferably, the nickel-cobalt sulfate solution obtained after washing with the second sulfuric acid solution in step (2) is subjected to adsorption treatment with chelating resin again. The adsorbed chelating resin is first washed with the first sulfuric acid solution to obtain a washing solution containing Mg and Mn, and then washed with the second sulfuric acid solution to obtain the nickel-cobalt sulfate solution.

[0023] Compared with the prior art, the beneficial effects of the present invention include:

[0024] This invention uses low-grade nickel matte as raw material to directly prepare battery-grade nickel-cobalt sulfate solution, significantly improving the recovery rate of nickel and cobalt and avoiding the loss of nickel and cobalt caused by further refining of low-grade nickel matte to high-grade nickel matte. The oxygen pressure leaching process selectively leaches nickel and cobalt from the low-grade nickel matte; this leaching process consumes virtually no sulfuric acid, with all dissolved sulfuric acid derived from Fe. 3+ Hydrolysis significantly reduces acid consumption during atmospheric pressure leaching. The pH of the leached filtrate is adjusted to remove iron and aluminum impurities, and then nickel and cobalt are selectively adsorbed using chelating resin to prepare a high-purity nickel-cobalt sulfate solution in one step. This eliminates the need for further nickel-cobalt separation and allows the solution to be directly used for the preparation of ternary precursors. Depending on the nickel-cobalt ratio in the solution, different proportions of nickel, cobalt, and manganese are added to ultimately synthesize the ternary precursor material. Attached Figure Description

[0025] Figure 1 This is a flowchart of a method for preparing battery-grade nickel cobalt manganese sulfate solution using low-grade nickel matte, as described in this invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] The low-grade nickel matte used in the examples and comparative examples had the following composition: Ni content 20-25% and iron content 55-65%.

[0028] The chelating resin used is IRC 748 chelating resin.

[0029] The concentration of the first sulfuric acid solution is 1 wt%, and the concentration of the second sulfuric acid solution is 10 wt%.

[0030] Example 1

[0031] A method for preparing battery-grade nickel-cobalt-manganese sulfate solution using low-grade nickel matte comprises the following steps:

[0032] (1) Grind 400g of low-grade nickel matte to -100 mesh and add 100g of 98% sulfuric acid solution. Leach at normal pressure for 4h to release gases such as H2 and H2S, and obtain the first slag phase and the first liquid phase. The first liquid phase is evaporated, concentrated and cooled to crystallize, and ferrous sulfate crystals are obtained. Add 10g of 98% sulfuric acid solution to the first slag phase and perform oxygen pressure leaching. The oxygen pressure leaching conditions are: temperature of 220℃, oxygen partial pressure of 30%, pressure of 3.5MPa, and leaching time of 4-8h, to obtain the second slag phase and the second liquid phase.

[0033] (2) Take the second liquid phase from step (1), add limestone to adjust the pH of the leachate to 3-4, and a precipitate will form. After filtering out the precipitate, obtain the filtrate. Adjust the pH of the filtrate to 2-4, and place 30g of chelating resin in a resin column to dynamically adsorb nickel and cobalt in the filtrate. Dynamically adsorb 400-500mL of filtrate for 10-20min. The chelating resin after adsorption is first washed with 10mL of a first sulfuric acid solution to obtain a washing solution containing Mg and Mn; then washed with 50mL of a second sulfuric acid solution to obtain a nickel-cobalt sulfate solution.

[0034] (3) Mix 50 ml of the nickel cobalt sulfate solution described in step (2) with 10 ml of washing solution containing Mg and Mn to prepare the nickel cobalt manganese sulfate solution.

[0035] After testing, it was found that after leaching under normal pressure in step (1), the leaching rate of Ni was <1%, and the leaching rate of iron was 50-60%.

[0036] After oxygen pressure leaching in step (1), the leaching rate of Ni is >95% and the leaching rate of iron is <3%.

[0037] Limestone was added to adjust the pH to 3-4 to produce a precipitate that removes Fe impurities, with a Fe removal rate of 90%.

[0038] After adsorption by chelating resin, the adsorption rates of Ni and Co are >99%, while the adsorption rates of Mn and Mg are 2%.

[0039] Example 2

[0040] A method for preparing battery-grade nickel-cobalt-manganese sulfate solution using low-grade nickel matte comprises the following steps:

[0041] The only difference between this embodiment and Embodiment 1 is that:

[0042] In step (1), the oxygen partial pressure is reduced to 10%, while other conditions remain unchanged.

[0043] After reducing the oxygen partial pressure, the leaching rate of Fe increased significantly by 20%, mainly as Fe2+.2+ It exists in the form of oxygen. The oxygen content is low, and Fe... 2 + Unable to oxidize to Fe 3+ The nitrogen cannot be hydrolyzed to Fe2O3, releasing sulfuric acid. Simultaneously, insufficient sulfuric acid dissolves Ni, causing the Ni leaching rate to decrease to 75%.

[0044] Example 3

[0045] A method for preparing battery-grade nickel-cobalt-manganese sulfate solution using low-grade nickel matte comprises the following steps:

[0046] The only difference between this embodiment and Embodiment 1 is that:

[0047] In step (1), the oxygen pressure leaching temperature is reduced to 180°C, while other conditions remain unchanged.

[0048] After the temperature decreases, Fe in the leachate 3+ The content is relatively high. This is mainly because the temperature of 180℃ is too low to effectively promote Fe. 3+ Hydrolysis resulted in a lower leaching rate for Ni and a higher leaching rate for Fe. Ultimately, the leaching rate for Fe was 18%, and the leaching rate for Ni was 68%.

[0049] Example 4

[0050] A method for preparing battery-grade nickel-cobalt-manganese sulfate solution using low-grade nickel matte comprises the following steps:

[0051] The only difference between this embodiment and Embodiment 1 is that:

[0052] With all other conditions being equal, the reaction pressure for the oxygen pressure reduction reaction is 2.8 MPa, and the oxygen partial pressure is 30%.

[0053] Changing the reactor pressure reduces the degree of iron hydrolysis. The leaching rate of Fe is 33%, and the leaching rate of Ni is 66%.

[0054] Comparative Example 1

[0055] A method for preparing a nickel cobalt manganese sulfate solution, comprising the following steps:

[0056] The only difference between this embodiment and Embodiment 1 is that:

[0057] After atmospheric pressure leaching, the first residue phase is treated with water at a liquid-to-solid mass ratio of 3:1, without the addition of concentrated sulfuric acid. Oxygen pressure leaching is then performed directly, with all other oxygen pressure conditions remaining the same.

[0058] Because low-grade nickel matte contains 8-15% sulfur, it can be converted into sulfuric acid under high-pressure oxygen conditions in an autoclave, providing the starting acid for the reaction. Ultimately, the leaching rate of Fe was 5%, and the leaching rate of nickel was 59%. Due to insufficient sulfur content, the leaching reaction of Ni was incomplete.

[0059] Comparative Example 2

[0060] A method for preparing a nickel cobalt manganese sulfate solution, comprising the following steps:

[0061] The only difference between this embodiment and Embodiment 1 is that:

[0062] In step (2), lime is not added to adjust the pH, and the liquid phase obtained after oxygen pressure leaching is directly used for chelation resin adsorption, with other conditions remaining the same.

[0063] In the leachate after direct oxygen pressure leaching, the Fe content is 3-5 g / L. Direct adsorption by the chelating resin results in competition for adsorption with Ni and Co, affecting the adsorption rates of Ni and Co. Under the same adsorption conditions, the adsorption rates of Ni and Co are <85%, while the adsorption rate of Iron is >10%, impacting the selective adsorption performance of the chelating resin.

[0064] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing battery-grade nickel-cobalt-manganese sulfate solution using low-grade nickel matte, characterized in that, Includes the following steps: (1) After grinding low-grade nickel matte, add concentrated sulfuric acid and perform atmospheric pressure leaching to obtain a first slag phase and a first liquid phase. Evaporate and concentrate the first liquid phase and cool it to crystallize to obtain ferrous sulfate crystals. Add concentrated sulfuric acid to the first slag phase and perform oxygen pressure leaching. (2) After oxygen pressure leaching in step (1), a second slag phase and a second liquid phase are obtained. The pH of the second liquid phase is adjusted to 3-4 to generate a precipitate. The precipitate is filtered out to obtain a filtrate. The filtrate is adsorbed by a chelating resin. The chelating resin after adsorption is first washed with a first sulfuric acid solution to obtain a washing solution containing Mg and Mn, and then washed with a second sulfuric acid solution to obtain a nickel-cobalt sulfate solution. (3) Mix the nickel cobalt sulfate solution described in step (2) with the washing liquid containing Mg and Mn to prepare the nickel cobalt manganese sulfate solution.

2. The method for preparing battery-grade nickel-cobalt-manganese sulfate solution with low-grade nickel matte according to claim 1, characterized in that, After grinding the low-grade nickel matte in step (1), concentrated sulfuric acid is added. The mass ratio of concentrated sulfuric acid to low-grade nickel matte is 0.1~0.5:

1.

3. The method for preparing battery-grade nickel-cobalt-manganese sulfate solution with low-grade nickel matte according to claim 1, characterized in that, Step (1) Add concentrated sulfuric acid to the first slag phase. The mass ratio of concentrated sulfuric acid to the first slag phase is 0.25:

1.

4. The method for preparing battery-grade nickel-cobalt-manganese sulfate solution with low nickel matte according to any one of claims 1 to 3, characterized in that, The conditions for oxygen pressure leaching in step (1) are: temperature of 180~220℃, oxygen partial pressure of 10~30%, pressure of 2.5~3.5MPa, and leaching time of 4~8h.

5. The method for preparing battery-grade nickel-cobalt-manganese sulfate solution with low-grade nickel matte according to claim 4, characterized in that, The concentration of the concentrated sulfuric acid in step (1) is 98 wt%; Step (2): The concentration of the first sulfuric acid solution is 0.5-3%; In step (2), the concentration of the second sulfuric acid solution is 8-13 wt%.

6. The method for preparing battery-grade nickel-cobalt-manganese sulfate solution with low-grade nickel matte according to claim 5, characterized in that, The particle size after grinding the low-nickel matte in step (1) is 50~200 mesh; The atmospheric pressure leaching time in step (1) is 1~4 hours.

7. The method for preparing battery-grade nickel-cobalt-manganese sulfate solution with low nickel matte according to any one of claims 1 to 3, characterized in that, Step (2) The method for adjusting the pH of the second liquid phase is to add limestone for adjustment.

8. The method for preparing battery-grade nickel-cobalt-manganese sulfate solution with low nickel matte according to any one of claims 1 to 3, characterized in that, The chelating resin in step (2) is IRC 748 chelating resin.

9. The method for preparing battery-grade nickel-cobalt-manganese sulfate solution with low-grade nickel matte according to claim 8, characterized in that, The method of using chelating resin to adsorb the filtrate in step (2) is as follows: at pH=2~4, the chelating resin dynamically adsorbs nickel and cobalt in the filtrate in the resin column. The amount of chelating resin used is 30g, the dynamic adsorption of 400~500mL of filtrate is 10~20min.

10. The method for preparing battery-grade nickel-cobalt-manganese sulfate solution with low-grade nickel matte according to claim 1, characterized in that, The nickel-cobalt sulfate solution obtained after washing with the second sulfuric acid solution in step (2) is then subjected to adsorption treatment with chelating resin. The adsorbed chelating resin is first washed with the first sulfuric acid solution to obtain a washing solution containing Mg and Mn, and then washed with the second sulfuric acid solution to obtain the nickel-cobalt sulfate solution.

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