Method for preparing battery-grade nickel-cobalt-manganese sulfate solution from low-nickel matte

Abstract

A method for preparing battery-grade nickel-cobalt-manganese sulfate solution from low-nickel matte. The method comprises: grinding low-nickel matte and adding concentrated sulfuric acid, then performing atmospheric pressure leaching, to obtain a first slag phase and a first liquid phase, and evaporating concentration - cooling crystallization of the first liquid phase, to obtain ferrous sulfate crystals; adding concentrated sulfuric acid to the first slag phase, performing oxygen pressure leaching to obtain a second slag phase and a second liquid phase, adjusting the pH value of the second liquid phase to 3-4, generating a precipitate, filtering the precipitate to obtain a filtrate, performing adsorption treatment on the filtrate using chelating resin, rinsing the chelating resin with a first sulfuric acid solution after adsorption, to obtain a rinsing solution containing Mg and Mn, and rinsing the rinsing solution using a second sulfuric acid solution, to obtain a nickel-cobalt sulfate solution; mixing the nickel-cobalt sulfate solution with the rinsing solution containing Mg and Mn, to obtain a nickel-cobalt-manganese sulfate solution. The battery-grade nickel-cobalt sulfate solution is prepared using low-nickel matte as a raw material, which improves the recovery rate of nickel and cobalt, and reduces acid consumption.

Description

A method for preparing battery-grade nickel cobalt manganese sulfate solution from low nickel matte Technical Field

[0001] The invention belongs to the field of metallurgy, and in particular relates to a method for preparing battery-grade nickel-cobalt-manganese sulfate solution from low-grade nickel matte. Background Art

[0002] Nickel sulfate is primarily divided into battery-grade nickel sulfate and electroplating-grade nickel sulfate. Battery-grade nickel sulfate is the primary source of nickel metal in ternary materials, used in the production of 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 charge capacity, the development of high-nickel ternary lithium batteries is an inevitable trend and will become the second largest area of ​​nickel consumption. Demand for electroplating-grade nickel sulfate is relatively stable and is widely used in the manufacturing of machinery, instruments, meters, medical devices, household appliances, and other industries.

[0003] Laterite nickel ore has gradually become the main source of nickel metal, among which the pyrometallurgical smelting process has been applied due to its advantages such as simple operation and short process flow. Among them, the process of "laterite nickel ore-electric furnace smelting (sulfurization)-low nickel matte-converter blowing-high nickel matte" has been adopted by smelters such as Tsingshan and Sorowako. That is, the laterite nickel ore is dried and pre-reduced in a rotary kiln, and then smelted in an electric furnace, and a sulfiding agent is added at the same time to obtain low nickel matte (Ni content of about 20%, iron content of about 65%), and then blown in a PS converter to prepare high nickel matte (Ni content of about 60%, iron content of about 5%). In the process of blowing from low nickel matte to high nickel matte, although the nickel content increases, it will lead to the loss of nickel and cobalt, resulting in waste of resources, and high energy consumption during blowing. Therefore, if a method can be provided for directly selecting and leaching nickel and cobalt using low nickel matte as raw material, it will not only shorten the engineering process, but also reduce the loss of nickel and cobalt.

[0004] Summary of the Invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a method for preparing battery-grade nickel cobalt manganese sulfate solution from low-grade nickel matte.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A method for preparing battery-grade nickel cobalt manganese sulfate solution from low-grade nickel matte comprises the following steps:

[0008] (1) grinding low-grade nickel matte and adding concentrated sulfuric acid to carry out atmospheric pressure leaching to obtain a first slag phase and a first liquid phase; evaporating and concentrating the first liquid phase and cooling and crystallizing it to obtain ferrous sulfate crystals; adding concentrated sulfuric acid to the first slag phase and carrying out oxygen pressure leaching;

[0009] The purpose of oxygen pressure leaching is to dissolve the Fe in the low nickel matte with sulfuric acid to generate Fe 2+ , oxidized to Fe by oxygen3+ The ore 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 a tailings pond, or the iron is recovered.

[0010] (2) After the 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, and the filtrate is subjected to adsorption treatment using a chelating resin. The adsorbed chelating resin is first washed with a first sulfuric acid solution to obtain a washing liquid containing Mg and Mn, and then washed with a second sulfuric acid solution to obtain a nickel-cobalt sulfate solution;

[0011] (3) The nickel cobalt sulfate solution of step (2) is mixed with a washing solution containing Mg and Mn to prepare a nickel cobalt manganese sulfate solution.

[0012] Preferably, concentrated sulfuric acid is added after grinding the nickel matte in step (1), and the mass ratio of concentrated sulfuric acid to nickel matte is 0.1 to 0.5:1.

[0013] 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.

[0014] Preferably, the conditions for the oxygen pressure leaching in step (1) are: temperature of 180-220° C., oxygen partial pressure of 10-30%, pressure of 2.5-3.5 MPa, and leaching time of 4-8 h.

[0015] Preferably, the concentration of the concentrated sulfuric acid in step (1) is 98 wt%;

[0016] Preferably, the particle size of the low-grade nickel matte after grinding in step (1) is 50 to 200 meshes;

[0017] Preferably, the time for the normal pressure leaching in step (1) is 1 to 4 hours.

[0018] Preferably, the concentration of the first sulfuric acid solution in step (2) is 0.5-3%;

[0019] Preferably, the concentration of the second sulfuric acid solution in step (2) is 8 to 13 wt%.

[0020] Preferably, the pH of the second liquid phase is adjusted in step (2) by adding limestone for adjustment.

[0021] Preferably, the chelating resin in step (2) is IRC 748 chelating resin.

[0022] Preferably, the method of adsorbing the filtrate with a chelating resin in step (2) is as follows: at pH = 2 to 4, the chelating resin dynamically adsorbs nickel and cobalt in the filtrate in a resin column, the amount of the chelating resin is 30 g, the amount of the chelating resin dynamically adsorbs 400 to 500 mL of the filtrate, and the adsorption time is 10 to 20 min.

[0023] Preferably, the nickel cobalt sulfate solution obtained after washing with the second sulfuric acid solution in step (2) is again subjected to adsorption treatment with a chelating resin, and the chelating resin after adsorption is first washed with a first sulfuric acid solution to obtain a washing liquid containing Mg and Mn, and then washed with a second sulfuric acid solution to obtain a nickel cobalt sulfate solution.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention uses low-grade nickel matte as raw material to directly prepare battery-grade nickel cobalt sulfate solution, which significantly improves the recovery rate of nickel and cobalt and avoids the loss of nickel and cobalt caused by further refining low-grade nickel matte to high-grade nickel matte. The oxygen pressure leaching process selectively leach nickel and cobalt from low-grade nickel matte. This leaching process basically does not consume sulfuric acid, and the dissolved sulfuric acid comes entirely from Fe 3+ The hydrolysis of the leaching agent significantly reduces the acid consumption of atmospheric pressure leaching. The pH of the filtrate after leaching is adjusted to remove iron and aluminum impurities, and then nickel and cobalt are selectively adsorbed by chelating resin to prepare a high-purity nickel-cobalt sulfate solution in one go. No further nickel and cobalt separation is required, and it can be directly used to prepare the ternary precursor. According to the nickel-cobalt ratio in the solution, different proportions of nickel, cobalt and manganese are added to finally synthesize the ternary precursor material. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a flow chart of a method for preparing battery-grade nickel cobalt manganese sulfate solution from low-grade nickel matte according to the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] The composition of the low-grade nickel matte used in the examples and comparative examples is: Ni content 20-25%, iron content 55-65%.

[0029] The chelating resin used was IRC 748 chelating resin.

[0030] The concentration of the first sulfuric acid solution is 1 wt %, and the concentration of the second sulfuric acid solution is 10 wt %.

[0031] Example 1

[0032] A method for preparing battery-grade nickel cobalt manganese sulfate solution from low-grade nickel matte, comprising the following steps:

[0033] (1) After grinding 400g of low-grade nickel matte to -100 mesh, 100g of 98% sulfuric acid solution was added and leached at normal pressure for 4h to release gases such as H2 and H2S to obtain a first slag phase and a first liquid phase; the first liquid phase was evaporated and concentrated and cooled and crystallized to obtain ferrous sulfate crystals; 10g of 98% sulfuric acid solution was added to the first slag phase and oxygen pressure leaching was performed; the conditions of oxygen pressure leaching were: temperature of 220°C, oxygen partial pressure of 30%, pressure of 3.5MPa, and leaching time of 4-8h to obtain a second slag phase and a second liquid phase;

[0034] (2) taking the second liquid phase of step (1), adding limestone to adjust the pH of the leachate to 3-4, generating a precipitate, filtering out the precipitate to obtain a filtrate, adjusting the pH of the filtrate to 2-4, placing 30g of chelating resin in a resin column to dynamically adsorb nickel and cobalt in the filtrate, dynamically adsorbing 400-500mL of the filtrate for 10-20min. The adsorbed chelating resin is first washed with a first sulfuric acid solution having a concentration of 10mL to obtain a washing solution containing Mg and Mn; and then washed with a second sulfuric acid solution having a concentration of 50mL to obtain a nickel-cobalt sulfate solution;

[0035] (3) Mix 50 ml of the nickel cobalt sulfate solution described in step (2) with 10 ml of a washing solution containing Mg and Mn to prepare a nickel cobalt manganese sulfate solution.

[0036] According to the test, after the normal pressure leaching in step (1), the leaching rate of Ni is less than 1%, and the leaching rate of iron is 50-60%.

[0037] After the oxygen pressure leaching in step (1), the leaching rate of Ni is greater than 95%, and the leaching rate of iron is less than 3%.

[0038] Limestone was added to adjust the pH to 3-4 to produce precipitation to remove the impurity Fe, with an Fe removal rate of 90%.

[0039] After adsorption by chelating resin, the adsorption rates of Ni and Co were >99%, while the adsorption amounts of Mn and Mg were only 2%.

[0040] Example 2

[0041] A method for preparing battery-grade nickel cobalt manganese sulfate solution from low-grade nickel matte, comprising the following steps:

[0042] The only difference between this embodiment and embodiment 1 is that:

[0043] In step (1), the oxygen partial pressure is reduced to 10%, and other conditions remain unchanged.

[0044] After reducing the oxygen partial pressure, the leaching rate of Fe increased significantly by 20%, mainly due to Fe 2+ Oxygen content is low, Fe 2+Unable to oxidize to Fe 3+ , unable to hydrolyze to Fe2O3 and release sulfuric acid. At the same time, there is not enough sulfuric acid to dissolve Ni, resulting in the Ni leaching rate dropping to 75%.

[0045] Example 3

[0046] A method for preparing battery-grade nickel cobalt manganese sulfate solution from low-grade nickel matte, comprising the following steps:

[0047] The only difference between this embodiment and embodiment 1 is that:

[0048] In step (1), the oxygen pressure leaching temperature is reduced to 180° C., and other conditions remain unchanged.

[0049] After the temperature is lowered, Fe 3+ The content is relatively high. This is mainly due to the low temperature of 180℃, which cannot effectively promote the 3+ Hydrolysis results in a lower leaching rate for Ni and a higher leaching rate for Fe. Ultimately, the leaching rates for Fe and Ni are 18% and 68%, respectively.

[0050] Example 4

[0051] A method for preparing battery-grade nickel cobalt manganese sulfate solution from low-grade nickel matte, comprising the following steps:

[0052] The only difference between this embodiment and embodiment 1 is that:

[0053] Other conditions were the same, the reaction pressure of the oxygen pressure reduction reaction was 2.8 MPa, and the oxygen partial pressure was 30%.

[0054] Changing the reactor pressure reduced the degree of iron hydrolysis, resulting in a 33% leaching rate for Fe and a 66% leaching rate for Ni.

[0055] Comparative Example 1

[0056] A method for preparing a nickel-cobalt-manganese sulfate solution comprises the following steps:

[0057] The only difference between this embodiment and embodiment 1 is that:

[0058] After atmospheric pressure leaching, the first residue phase was treated with water at a liquid-to-solid mass ratio of 3:1 without the addition of concentrated sulfuric acid. Oxygen pressure leaching was then performed directly, with other oxygen pressure conditions remaining the same.

[0059] Since nickel matte contains 8-15% sulfur, it can be converted into sulfuric acid under the oxygen pressure of the autoclave, providing the starting acid for the reaction. The final leaching rate of Fe is 5%, and the leaching rate of nickel is 59%. Due to the insufficient sulfur content, the nickel leaching reaction cannot be completed.

[0060] Comparative Example 2

[0061] A method for preparing a nickel-cobalt-manganese sulfate solution comprises the following steps:

[0062] The only difference between this embodiment and embodiment 1 is that:

[0063] In step (2), lime is not added to adjust the pH, and the liquid phase obtained after oxygen pressure leaching is directly subjected to chelating resin adsorption, while other conditions are the same.

[0064] The Fe content in the leachate after direct oxygen pressure leaching is 3-5 g / L. Direct adsorption by chelating resin occurs, competing with Ni and Co for adsorption, 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%, affecting the selective adsorption performance of the chelating resin.

[0065] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing battery-grade nickel cobalt manganese sulfate solution from low-grade nickel matte, characterized in that: The steps include: (1) grinding low-grade nickel matte and adding concentrated sulfuric acid to carry out leaching at normal pressure to obtain a first slag phase and a first liquid phase, evaporating and concentrating the first liquid phase and cooling and crystallizing it to obtain ferrous sulfate crystals; adding concentrated sulfuric acid to the first slag phase and carrying out oxygen pressure leaching; (2) After the 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, and the filtrate is adsorbed by a chelating resin. The adsorbed chelating resin is first washed with a first sulfuric acid solution to obtain a washing liquid containing Mg and Mn, and then washed with a second sulfuric acid solution to obtain a nickel-cobalt sulfate solution; (3) The nickel cobalt sulfate solution of step (2) is mixed with the washing liquid containing Mg and Mn to prepare a nickel cobalt manganese sulfate solution.

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

1.

3. The method for preparing battery-grade nickel cobalt manganese sulfate solution from low nickel matte according to claim 1, characterized in that: 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.

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

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

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

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

8. The method for preparing battery-grade nickel cobalt manganese sulfate solution from 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 from low nickel matte according to claim 8, characterized in that: The method of using a 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 a resin column, the chelating resin is used in an amount of 30 g, the filtrate is dynamically adsorbed to 400 to 500 mL, and the adsorption time is 10 to 20 min.

10. The method for preparing battery-grade nickel cobalt manganese sulfate solution from low 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 again subjected to adsorption treatment by a chelating resin. The chelating resin after adsorption is first washed with a first sulfuric acid solution to obtain a washing liquid containing Mg and Mn, and then washed with a second sulfuric acid solution to obtain a nickel cobalt sulfate solution.

Images