A method for preparing nickel sulfate from crude nickel-cobalt hydroxide

Abstract

The application discloses a method for preparing nickel sulfate from crude nickel-cobalt hydroxide, which comprises the following steps: slurry, acid leaching, reaction, aging, solid-liquid separation and the like. The method for preparing nickel sulfate from crude nickel-cobalt hydroxide directly slurries the crude nickel-cobalt hydroxide after acid leaching, does not need to add a reducing agent, saves the cost, shortens the reaction time, and greatly improves the production efficiency. In the prior art, the silicon removal process needs to readjust the pH to a relatively high value, consumes a large amount of alkali, and has a low nickel recovery rate. The method for preparing nickel sulfate from crude nickel-cobalt hydroxide can remove silicon through aging, and the silicon removal rate can reach 40%-60%. Moreover, the method can reduce the leaching of manganese by about 50%, can save the cost of the later extraction process, and can improve the production capacity of the extraction process.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgy, specifically relating to a method for preparing nickel sulfate from crude nickel cobalt hydroxide. Background Technology

[0002] In recent years, with the continuous development and utilization of nickel sulfide ore resources leading to their decreasing availability, and the rapid development of the high-nickel ternary lithium-ion battery new energy industry, the development of laterite nickel ore, which accounts for more than 60% of global nickel resource reserves, has attracted widespread attention from researchers. There are three main processing technologies for laterite nickel ore, among which the crude nickel cobalt hydroxide (MHP) process has gradually become the industry mainstream due to its low investment, low operating costs, and high safety. Therefore, leaching with crude nickel cobalt hydroxide (MHP) as raw material is one of the main methods for preparing battery-grade nickel sulfate and cobalt sulfate.

[0003] In existing technologies, crude nickel-cobalt hydroxide (MHP) is mainly prepared into nickel sulfate and cobalt sulfate through a "reduction acid leaching-extraction purification" process. This method requires the recovery and treatment of manganese, which is not only costly and inefficient, but also results in MHP with a high silicon content, making it difficult to filter after acid leaching, leading to low production efficiency. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for preparing nickel sulfate from crude nickel cobalt hydroxide, specifically including the following:

[0005] A method for preparing nickel sulfate from crude nickel cobalt hydroxide, wherein the prepared nickel sulfate is a crude nickel sulfate solution, comprising the following steps:

[0006] (1) Pulping: Water is added to crude nickel-cobalt hydroxide in a ratio of 1:(1-1.5) to pulping, and nickel-cobalt hydroxide slurry is obtained;

[0007] (2) Acid leaching: Add sulfuric acid solution to nickel-cobalt hydroxide slurry to adjust the pH of nickel-cobalt hydroxide slurry to 1-1.5, and then carry out acid leaching at 60-80℃;

[0008] (3) Reaction: Add lime milk to the acid-leached slurry to adjust the pH of the slurry to 4.5-5.5. After the pH stabilizes, stir and react at 60-80℃.

[0009] (4) Aging: The reaction system after the reaction is completed is aged for 1-3 days;

[0010] (5) Solid-liquid separation: The aged reaction system is subjected to solid-liquid separation to obtain nickel sulfate solution and solid slag.

[0011] Preferably, the acid leaching time in step (2) is 0.5-5 hours.

[0012] Preferably, the reaction time in step (3) is 0.5-2 hours.

[0013] Preferably, the aging process in step (4) is carried out under low-speed stirring conditions of 0.3-0.6 r / min or in a thickener, and the aging temperature is 55-80℃, preferably 55℃.

[0014] Preferably, the temperature of the aged reaction system in step (5) is 55-80℃.

[0015] Preferably, the process also includes step (6) solid slag treatment: after the obtained solid slag is slurried, sulfuric acid is added for acid washing, and after acid washing, it is washed with water multiple times to obtain landfill slag.

[0016] Preferably, the solid-liquid ratio of the solid slurry in step (6) is 1:(2-3).

[0017] Preferably, the pH of the pickling control slurry system in step (6) is 1.5-2.0 and the temperature is 55-70℃.

[0018] The beneficial effects of this invention are:

[0019] (1) In the prior art, the preparation of nickel sulfate from crude nickel hydroxide cobalt requires a large amount of reducing agent for reduction reaction, and the reaction time is very long. However, the method for preparing nickel sulfate from crude nickel hydroxide cobalt disclosed in this invention directly slurries the crude nickel hydroxide cobalt and then acid-leaches it without adding a reducing agent. This saves costs and shortens the reaction time, greatly improving production efficiency.

[0020] (2) In the existing technology, the desiliconization process requires adjusting the pH to a relatively high value, which consumes a large amount of alkali, and the nickel recovery rate is low. The method for preparing nickel sulfate from crude nickel-cobalt hydroxide disclosed in this invention can achieve a silicon removal rate of 40%-60% through aging. Moreover, the method disclosed in this invention can reduce manganese leaching by about 50%, which can save the cost of subsequent extraction processes and improve the production capacity of the extraction process. Attached Figure Description

[0021] Figure 1 The present invention describes the process flow of the method disclosed herein. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments shown below do not limit the scope of the invention as described in the claims. Furthermore, the complete contents of the configurations illustrated in the following embodiments are not limited to those necessary for the solution of the invention as described in the claims.

[0023] A method for preparing nickel sulfate from crude nickel cobalt hydroxide includes the following steps:

[0024] (1) Slurrying: Water is added to crude nickel-cobalt hydroxide in a ratio of 1:(1-1.5) (e.g., 1:1, 1:1.1, 1:1.2, 1:1.4, etc.) to slurry and obtain nickel-cobalt hydroxide slurry;

[0025] (2) Acid leaching: Add sulfuric acid solution to nickel-cobalt hydroxide slurry to adjust the pH of nickel-cobalt hydroxide slurry to 1-1.5 (e.g. 1.1, 1.2, 1.3, 1.4, etc.), and then carry out acid leaching at 60-80℃ (e.g. 62℃, 64℃, 68℃, 70℃, 72℃, 75℃, 78℃, etc.) for 0.5-5h (e.g. 0.8h, 1h, 2h, 3h, 4h, etc.);

[0026] (3) Reaction: Add lime milk to the acid-leached slurry to adjust the pH of the slurry to 4.5-5.5 (e.g., 4.6, 4.8, 5.0, 5.2, 5.4, etc.). After the pH stabilizes, stir the reaction at 60-80℃ (e.g., 62℃, 64℃, 68℃, 70℃, 72℃, 75℃, 78℃, etc.) for 0.5-2h (e.g., 0.6h, 0.8h, 1.0h, 1.5h, 1.8h, etc.).

[0027] (4) Aging: The reaction system after the reaction is completed is aged for 1-3 days (e.g., 1.5 days, 2 days, 2.5 days, etc.); the aging is carried out under low-speed stirring conditions of 0.3-0.6 r / min (e.g., 0.3 r / min, 0.4 r / min, 0.5 r / min, 0.6 r / min, etc.) or in a thickener, and the aging temperature is 55-80℃ (e.g., 60℃, 65℃, 70℃, 75℃, etc., preferably 55℃);

[0028] (5) Solid-liquid separation: The aged reaction system is subjected to solid-liquid separation at a temperature of 55-80℃ (e.g., 60℃, 64℃, 68℃, 70℃, 72℃, 75℃, 78℃, etc.) to obtain nickel sulfate solution and solid slag.

[0029] (6) Solid slag treatment: The obtained solid slag is slurried with a solid-liquid ratio of 1:(2-3) (e.g., 1:2, 1:2.2, 1:2.5, 1:2.8, etc.). Then sulfuric acid is added for acid washing. The pH of the slurry system is controlled at 1.5-2.0 (e.g., 1.6, 1.7, 1.8, 1.9, etc.) and the temperature is controlled at 55-70℃ (e.g., 60℃, 64℃, 68℃, 70℃, etc.). After acid washing, the slag is washed with water multiple times to obtain landfill slag.

[0030] Experiments have verified that the method for preparing nickel sulfate from crude nickel cobalt hydroxide disclosed in this invention can achieve a silicon removal rate of 40%-60% through aging to remove silicon. Furthermore, the method disclosed in this invention can reduce manganese leaching by approximately 50%.

[0031] Example 1

[0032] A method for preparing nickel sulfate (solution) using MHP raw materials includes the following steps:

[0033] (1) Pulping: Open the tap water valve, add 400 liters of tap water to the pulping reactor through the water meter, add 400 kg of MHP raw material and stir to make pulp, and then transport it to the acid leaching reactor through the transfer tank.

[0034] (2) Acid leaching: Open the sulfuric acid valve to adjust the pH of the solution to 1.3, open the steam valve, maintain the temperature at about 60°C during the reaction, and react for 3 hours to obtain acid leaching slurry.

[0035] (3) Reaction: Open the lime milk valve to adjust the pH to 4.7, react for 1 hour, and obtain the neutralized and impurity-removed slurry.

[0036] (4) Aging: After impurity removal, the slurry is stirred at low speed in the reactor for 2 days at a stirring speed of 0.5 r / min, and steam is turned on before pressure filtration to maintain the temperature at 55℃.

[0037] (5) Solid-liquid separation: After the heating is completed, open the bottom valve of the reactor and the feed valve of the filter press to filter the aged slurry. The filtration time is 26 minutes, the filter residue is 105 kg, and the filtrate is 532 liters. Take a sample to analyze nickel, manganese and silicon.

[0038] (6) Filter press residue treatment: After the filter press residue is slurried, it is sent to the acid washing reactor. The acid washing pH is controlled at 1.6 and the washing temperature is 60℃. After the residue is qualified, it is put into the countercurrent water washing reactor. After three countercurrent washings, samples are taken for analysis of nickel and cobalt.

[0039] Analysis revealed that the liquid sample contained 123.25 g / L nickel, 9.08 g / L manganese, and 41.3 mg / L silicon. The manganese leaching rate was only 33.23%, and the silicon content in the liquid sample was less than the standard of 60 mg / L, thus meeting the extraction quality standard.

[0040] The slag sample contained 0.14% cobalt and 0.33% nickel, meeting the quality control standard that the cobalt content in the slag is less than 0.3% and the nickel content is less than 0.5%.

[0041] Example 2

[0042] A method for preparing crude nickel sulfate (solution) from MHP raw material includes the following steps:

[0043] (1) Pulping: Open the tap water valve, add 400 liters of tap water to the pulping reactor through the water meter, add 600 kg of MHP raw material and stir to make pulp, and then transport it to the acid leaching reactor through the transfer tank.

[0044] (2) Acid leaching: Open the sulfuric acid valve to adjust the pH of the solution to 1.0, open the steam valve, maintain the temperature at about 60°C during the reaction, and react for 4 hours to obtain acid leaching slurry.

[0045] (3) Reaction: Open the lime slurry valve to adjust the pH to 5.0, react for 1.5 hours, and obtain the neutralized and impurity-removed slurry.

[0046] (4) Aging: The slurry after impurity removal is stirred at low speed in the reactor for 2.5 days at a stirring speed of 0.5 r / min, and steam is turned on before pressure filtration to maintain the temperature at 60℃.

[0047] (5) Solid-liquid separation: After the heating is completed, open the bottom valve of the reactor and the feed valve of the filter press to filter the aged slurry. The filtration time is 18 minutes, the filter residue is 101 kg, and the filtrate is 619 liters. Take a liquid sample to analyze nickel, manganese and silicon.

[0048] (6) Filter press residue treatment: After the filter press residue is slurried, it is sent to the acid washing reactor. The acid washing pH is controlled at 1.8 and the washing temperature is 60℃. After the residue is qualified, it is put into the countercurrent water washing reactor. After three countercurrent washings, samples are taken for analysis of nickel and cobalt.

[0049] Analysis revealed that the liquid sample contained 93.47 g / L nickel, 8.36 g / L manganese, and 30.5 mg / L silicon. The manganese leaching rate was only 36.34%, and the silicon content in the liquid sample was less than the standard of 60 mg / L, thus meeting the extraction quality standard.

[0050] The slag sample contained 0.09% cobalt and 0.26% nickel, meeting the quality control standard that the cobalt content in the slag is less than 0.3% and the nickel content is less than 0.5%.

[0051] Example 3

[0052] A method for preparing crude nickel sulfate solution using MHP raw material includes the following steps:

[0053] (1) Pulping: Open the tap water valve, add 400 liters of tap water to the pulping reactor through the water meter, add 500 kg of MHP raw material and stir to make pulp, and then transport it to the acid leaching reactor through the transfer tank.

[0054] (2) Acid leaching: Open the sulfuric acid valve to adjust the pH of the solution to 1.5, open the steam valve, maintain the temperature at about 60°C during the reaction, and react for 5 hours to obtain acid leaching slurry.

[0055] (3) Reaction: Open the lime milk valve to adjust the pH to 4.8, react for 2.0 h, and obtain the neutralized and impurity-removed slurry.

[0056] (4) Aging: The slurry after impurity removal is stirred at low speed in the reactor for 3 days at a stirring speed of 0.3 r / min, and steam is turned on before pressure filtration to maintain the temperature at 70℃.

[0057] (5) Solid-liquid separation: After heating is completed, open the bottom valve of the reactor and the feed valve of the filter press to filter the aged slurry. The filtration time is 14 minutes, the filter residue is 112 kg, the filtrate is 596 liters, and liquid samples are taken for analysis of nickel, manganese and silicon.

[0058] (6) Filter press residue treatment: After the filter press residue is slurried, it is sent to the acid washing reactor. The acid washing pH is controlled at 2.0 and the washing temperature is 70℃. After the residue is qualified, it is put into the countercurrent water washing reactor. After three countercurrent washings, samples are taken for analysis of nickel and cobalt.

[0059] Analysis revealed that the liquid sample contained 106.47 g / L nickel, 8.87 g / L manganese, and 48.3 mg / L silicon. The manganese leaching rate was only 37.12%, and the silicon content in the liquid sample was less than the standard of 60 mg / L, thus meeting the extraction quality standard.

[0060] The slag sample contained 0.16% cobalt and 0.42% nickel, meeting the quality control standard that the cobalt content in the slag is less than 0.3% and the nickel content is less than 0.5%.

[0061] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing nickel sulfate from crude nickel cobalt hydroxide, characterized in that, Includes the following steps: (1) Pulping: Water is added to crude nickel-cobalt hydroxide in a ratio of 1:(1-1.5) to pulping, and nickel-cobalt hydroxide slurry is obtained; (2) Acid leaching: Add sulfuric acid solution to nickel-cobalt hydroxide slurry to adjust the pH of nickel-cobalt hydroxide slurry to 1-1.5, and then carry out acid leaching at 60-80℃ for 0.5-5h; (3) Reaction: Add lime milk to the acid-leached slurry to adjust the pH of the slurry to 4.5-5.

5. After the pH stabilizes, stir the reaction at 60-80℃ for 0.5-2 hours. (4) Aging: The reaction system after the reaction is completed is aged for 1-3 days. The aging is carried out under low-speed stirring at a speed of 0.3-0.6 r / min or in a thickener. The aging temperature is 55-80℃. (5) Solid-liquid separation: The aged reaction system is subjected to solid-liquid separation at a temperature of 55-80℃ to obtain nickel sulfate solution and solid slag; (6) Solid slag treatment: After the obtained solid slag is slurried, sulfuric acid is added for acid washing, and after acid washing, it is washed with water multiple times to obtain landfill slag; the solid-liquid ratio of the solid slag slurry is 1:(2-3), and the pH of the slurry system is controlled at 1.5-2.0 and the temperature is 55-70℃ during acid washing.

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