A method for removing zinc impurities from nickel sulfate solution

Abstract

The present invention relates to a method for removing zinc impurities from a nickel sulfate solution. The method comprises adsorbing the nickel sulfate solution through a resin, desorbing the solution with hydrochloric acid, and converting the solution into a nickel chloride solution. The resulting solution is concentrated using a nanofiltration device, and zinc is adsorbed by another resin to obtain a zinc-removed nickel chloride solution. The nickel chloride solution is then adsorbed by a third resin and desorbed again with sulfuric acid to obtain a nickel sulfate solution. The method uses an ion exchange resin to convert the nickel sulfate solution into nickel chloride, and then deeply removes zinc, so that the zinc ion content in the solution is stably controlled to below 0.3 ppm, and then converts the solution into nickel sulfate. The entire process can be completed at room temperature.

Description

Technical Field

[0001] The invention relates to a method for removing zinc impurities from a nickel sulfate solution. Background Art

[0002] Nickel sulfate is a key raw material for battery production, but nickel-containing wastewater often contains numerous impurities that interfere with nickel extraction and affect nickel sulfate performance. Currently, the primary method for removing zinc impurities is extraction separation. Organic extraction uses organic matter, primarily P204 and P507 extractants, resulting in a lengthy process, multiple stages, a large footprint, and the introduction of organic matter. Ion exchange, on the other hand, primarily uses various types of resins to remove impurities through adsorption. This is simple, convenient, and requires minimal floor space. However, there are currently no resins that can clearly distinguish between nickel and zinc impurities in nickel sulfate.

[0003] Therefore, exploring a process for removing impurities from nickel sulfate with a short process flow and low investment cost will play a significant role in improving the economic benefits of nickel sulfate. Summary of the Invention

[0004] The problem to be solved by the present invention is to remove low-content zinc in a nickel sulfate solution and improve the purity of the nickel sulfate.

[0005] In order to solve the above problems, the technical solution of the present invention is to provide a method for removing zinc impurities, the steps of which are as follows:

[0006] (1) Using resin A to adsorb nickel sulfate until saturation;

[0007] (2) using hydrochloric acid for desorption to obtain a nickel chloride solution;

[0008] (3) concentrating the obtained nickel chloride solution using a nanofiltration device;

[0009] (4) using resin B to remove zinc impurities in the nickel chloride solution;

[0010] (5) using resin C to adsorb the nickel chloride solution after zinc removal until saturation;

[0011] (6) Desorption with sulfuric acid can obtain nickel sulfate solution.

[0012] Furthermore, in the step (1), the resin A is one or more of aminophosphoric acid, carboxyamino, pyridine, silicate carboxyamino, cationic, and thiourea resins.

[0013] Furthermore, in step (2), the desorption liquid of resin A is hydrochloric acid, and its content ranges from 5% to 10%.

[0014] Furthermore, in step (3), the nickel content in the nickel chloride solution after nanofiltration is 30-50 g / L.

[0015] Furthermore, in step (4), the resin B is a weakly basic amino anion resin.

[0016] Furthermore, in step (5), the resin C is one or more of a cationic resin, a chelating resin, and a carboxylic acid resin.

[0017] Furthermore, in step (6), the desorption liquid of resin C is sulfuric acid, and its content ranges from 5% to 10%.

[0018] Furthermore, in steps (1), (4) and (5), the flow direction is downstream adsorption.

[0019] Furthermore, in steps (2) and (6), the flow direction is countercurrent desorption.

[0020] Compared with the prior art, the present invention can transform the nickel sulfate solution into the nickel chloride solution mainly through ion exchange technology without introducing impurities, and remove the zinc impurity content to below 0.3ppm in this form. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The figure is a flow chart of the process of the present invention. DETAILED DESCRIPTION

[0022] A method for removing zinc impurities from a nickel sulfate solution is as follows:

[0023] (1) using resin A to adsorb nickel sulfate solution containing zinc impurities until the nickel adsorption is saturated; the type of resin A is one or more of aminophosphoric acid, carboxylamino, pyridine, silicate carboxylamino, cationic, and thiourea resins;

[0024] (2) Countercurrent desorption using 10% hydrochloric acid at room temperature yielded a nickel chloride solution with a nickel content of 9.77 g / L;

[0025] (3) using a nanofiltration device to concentrate the obtained nickel chloride solution, wherein the nickel content after concentration is 38.8 g / L and the zinc content is 0.15 g / L;

[0026] (4) Resin B was used to remove zinc impurities from nickel chloride solution, and the zinc content in the effluent was 0.142 ppm; Resin B is a weakly basic amino anion resin.

[0027] (5) Using resin C to adsorb the nickel chloride solution after zinc removal until the nickel adsorption is saturated; the type of resin C is one or more of cationic resin, chelating resin, and carboxylic acid resin.

[0028] (6) Desorption is performed using 10% sulfuric acid at room temperature to obtain a nickel sulfate solution.

[0029] The present invention can transform the nickel sulfate solution into the nickel chloride solution mainly through ion exchange technology without introducing impurities, and remove the zinc impurity content to below 0.3ppm in this form.

[0030] The above describes one embodiment of the present invention in detail, but the content is only the best implementation example of the present invention and does not represent the full scope of implementation of the invention. All equivalent changes and improvements made within the scope of the invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for removing zinc impurities from a nickel sulfate solution, characterized in that: The following steps are involved: (1) Using resin A to adsorb nickel sulfate until saturation; (2) using hydrochloric acid for desorption to obtain a nickel chloride solution; (3) concentrating the obtained nickel chloride solution using a nanofiltration device; (4) using resin B to remove zinc impurities in the nickel chloride solution; (5) using resin C to adsorb the nickel chloride solution after zinc removal until saturation; (6) Desorption with sulfuric acid can obtain nickel sulfate solution; Resin A type is one or more of aminophosphoric acid, carboxylamino, pyridine, silicate carboxylamino, cationic, and thiourea resins; Resin B type is a weakly basic amino anion resin; Resin C type is one of cationic resin, chelating resin, and carboxylic acid resin.

2. The method for removing zinc impurities from a nickel sulfate solution according to claim 1, wherein the desorption liquid of resin A is hydrochloric acid, and its content ranges from 5% to 10%.

3. The method for removing zinc impurities from a nickel sulfate solution according to claim 1, wherein the nickel content in the nickel chloride solution after nanofiltration is 30-50 g / L.

4. The method for removing zinc impurities from a nickel sulfate solution according to claim 1, wherein the desorption liquid of the resin C is sulfuric acid, and the content of sulfuric acid is in the range of 5-10%.

5. The method for removing zinc impurities from nickel sulfate solution according to claim 1, wherein the flow direction during adsorption is downstream.

6. The method for removing zinc impurities from nickel sulfate solution according to claim 1, wherein the flow direction during desorption is countercurrent.

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