A method for refining high-impurity nickel sulfate

Abstract

The present invention belongs to the technical field of hydrometallurgy, and in particular relates to a refining method for high-impurity nickel sulfate, comprising the following steps: (1) dissolving: adding water to the high-impurity nickel sulfate to dissolve it, thereby obtaining a high-impurity nickel liquid; (2) removing arsenic and iron: heating the high-impurity nickel liquid to 60-95° C., adding a neutralizing agent, adjusting the pH value of the system to 3.0-3.5, and performing solid-liquid separation to obtain arsenic slag and arsenic-removed iron liquid; (3) deep impurity removal: adding zirconium hydroxide to the arsenic-removed iron liquid, adjusting the pH value of the system to 4.5-6.0, and performing solid-liquid separation to obtain impurity-removed slag and impurity-removed liquid; (4) extracting and purifying: accurately filtering the impurity-removed liquid, adding P204, extracting and removing manganese, calcium and zinc, and performing phase separation to obtain a P204 raffinate and a loaded organic phase I; and adding P507 or C272 to the P204 raffinate, extracting and removing cobalt and magnesium, and performing phase separation to obtain a refined nickel sulfate solution and a loaded organic phase IV. The present invention can deeply remove impurities such as arsenic, iron, aluminum, silicon, fluorine, chromium, copper, calcium, manganese, zinc, cobalt and magnesium in crude nickel sulfate without introducing impurities, and the removed slag can be recycled and reused.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for refining high-impurity nickel sulfate. Background Art

[0002] Industrial nickel sulfate is often called crude nickel sulfate. Its main source is a by-product of copper smelting. The impurities in it are usually of many types and high content. Common impurities include: arsenic, iron, aluminum, silicon, fluorine, chromium, copper, calcium, manganese, zinc, cobalt, and magnesium. The valence states of arsenic are +3 and +5, the valence states of iron are +2 and +3, and the valence states of chromium are +6 and +3. Due to the complexity of the valence states, the existing technology cannot remove all of the above impurities through a single method. Instead, it is often necessary to convert them into the same valence state through redox reactions. , and the impurity removal process has the following problems: (1) Commonly used arsenic removers can only remove +5 valence arsenic; (2) Commonly used impurity removers cannot simultaneously remove aluminum, silicon, fluorine, chromium, and copper; (3) Commonly used impurity removers cannot simultaneously remove +6 and +3 valence chromium, but can only remove +3 valence chromium that is easily hydrolyzed; (4) Most commonly used impurity removers can only be used once and cannot be desorbed, regenerated, and recycled; (5) Impurity removal will also introduce new impurities, which need to be further removed, resulting in an increase in the impurity removal process. Summary of the Invention

[0003] In order to solve the problems in the prior art of high-impurity nickel sulfate, such as high impurities, many types of impurities, and a long impurity removal process, the present invention provides a refining method for high-impurity nickel sulfate, which can deeply remove impurities such as arsenic, iron, aluminum, silicon, fluorine, chromium, copper, calcium, manganese, zinc, cobalt, and magnesium in crude nickel sulfate, thereby realizing the refining of high-impurity nickel sulfate. In addition, no impurities are introduced during the refining process, and the impurity removal residue can be recycled, which is beneficial to environmental protection and cost savings.

[0004] The technical solution of the present invention is:

[0005] A method for refining high-impurity nickel sulfate comprises the following steps:

[0006] (1) Dissolving: adding water to dissolve high-mix nickel sulfate to obtain a high-mix nickel solution;

[0007] (2) Arsenic and iron removal: The high-impregnation nickel solution is heated to 60-95°C, a neutralizer is added to adjust the pH of the system to 3.0-3.5, and the solid-liquid separation is performed to obtain arsenic slag and arsenic-removed iron solution;

[0008] (3) Deep impurity removal: zirconium hydroxide is added to the arsenic removal iron liquid to adjust the pH of the system to 4.5-6.0, and solid-liquid separation is performed to obtain impurity-removed slag and impurity-removed liquid;

[0009] (4) Extraction and purification: After precise filtration of the impurity-removed liquid, P204 is added to extract and remove manganese, calcium, and zinc, and the phases are separated to obtain a P204 raffinate and a loaded organic phase I; P507 or C272 is added to the P204 raffinate to extract and remove cobalt and magnesium, and the phases are separated to obtain a refined nickel sulfate solution and a loaded organic phase IV.

[0010] Furthermore, in step (1), the impurities in the high-impurity nickel sulfate include arsenic, iron, aluminum, silicon, fluorine, chromium, copper, calcium, manganese, zinc, cobalt, and magnesium, and the high-impurity nickel solution is acidic.

[0011] Furthermore, in step (1), the nickel ion concentration in the highly impure nickel solution is 80-120 g / L and the pH is 0.5-2.5.

[0012] Furthermore, in step (2), the neutralizing agent is nickel hydroxide.

[0013] Furthermore, in step (3), the impurity removal temperature is 20-95° C., and the impurity removal time is 0.5-4 h.

[0014] Furthermore, in step (4), the volume concentration of P204 is 20-25%, the volume concentration of P507 is 15-20%, and the single-stage extraction time is 10-20 min.

[0015] The present invention further comprises the following steps: removing oil from the refined nickel sulfate solution in step (4) by using activated carbon, evaporating and crystallizing, and obtaining battery-grade nickel sulfate crystals.

[0016] The present invention also includes the following steps: first washing nickel with pure water in the loaded organic phase I, then adding dilute sulfuric acid for back extraction and phase separation, controlling the pH of the aqueous phase to 2.0-2.5, to obtain a manganese-calcium back extraction liquid and a loaded organic phase II, then adding dilute sulfuric acid for back extraction and phase separation, controlling the pH of the aqueous phase to 1.0-1.8, to obtain a zinc-containing back extraction liquid and a loaded organic phase III, and the loaded organic phase III is the regenerated P204, which can be returned to step (4) for use.

[0017] The present invention further comprises the following steps: washing nickel with pure water in the loaded organic phase IV, then adding dilute sulfuric acid for back extraction and phase separation, controlling the pH of the aqueous phase to be 3.5-4.5, to obtain a magnesium-containing back extraction liquid and a loaded organic phase V, then adding dilute sulfuric acid for back extraction and phase separation, controlling the pH of the aqueous phase to be 2.0-2.5, to obtain a cobalt-containing back extraction liquid and a loaded organic phase VI, the loaded organic phase VI being the regenerated P507 or the regenerated C272, which can be returned to step (4) for use.

[0018] The present invention further comprises the following steps: washing the impurity removal slag with water to remove the nickel sulfate solution carried therein to obtain an impurity removal slag washing liquid; adding sulfuric acid to the impurity removal slag washing liquid to adjust the pH to 1.0-1.5 for desorption to obtain a first desorption liquid and a first desorption slag; adding liquid alkali to the first desorption slag to adjust the pH to 10-12 to obtain a second desorption liquid and a second desorption slag; washing the second desorption slag with sodium with the impurity removal slag washing liquid to obtain regenerated zirconium hydroxide; and the regenerated zirconium hydroxide can be returned to step (3) for use.

[0019] The principles of each step of the present invention are as follows:

[0020] 1. Removal of arsenic and iron: The main valence states of iron in high-mix nickel sulfate are +3 and +2, and the main valence states of arsenic are +5 and +3. Since high-mix nickel sulfate is acidic, the above ions enter the solution during the dissolution process with water, and there is basically no precipitation. The existence forms of the above ions in the high-mix nickel solution are Fe 2+ 、Fe 3+ 、AsO4 3- 、AsO3 3- .

[0021] Nickel in nickel hydroxide mainly exists in the form of +2 valence. When it is added to the acidic high-mix nickel solution, a neutralization reaction occurs to generate nickel sulfate. Nickel hydroxide often contains a small amount of manganese at the same time. The valence of this part of manganese is +2 and +4. The +2 valence manganese hydroxide is neutralized and dissolved together with the nickel to generate manganese sulfate. However, the +4 valence manganese is manganese dioxide. Under the condition of only sulfuric acid and no reducing agent, it cannot be converted into +2 valence manganese sulfate and enter the high-mix nickel solution. However, manganese dioxide has strong oxidizing properties and can reduce the Fe in the high-mix nickel solution. 2+ Oxidized to Fe 3+ , and the +3 valence AsO3 3- Oxidized to +5-valent AsO4 3- At the same time, manganese dioxide is reduced to +2 manganese ions, and arsenate and manganese can be further converted into stable manganese arsenate precipitates. 2+ Oxidized to Fe 3+ 、AsO3 3- Oxidized to AsO4 3- The purpose of removing iron and arsenic simultaneously can be achieved by the double decomposition reaction of the two, and the double decomposition reaction of manganese and ferric arsenate to form manganese arsenate precipitate. The main components of arsenic slag are ferric arsenate and manganese arsenate. With the introduction of nickel hydroxide, the excess iron ions can be hydrolyzed to form ferric hydroxide precipitate or converted into goethite precipitate under the condition of pH 3.0-3.5. The main chemical reactions occurring in the high-impurity nickel solution are as follows:

[0022] M(OH)2+H2SO4=MSO4+H2O M=Ni(Ⅱ), Mn(Ⅱ)

[0023] MnO2+2Fe 2+ +4H + =Mn 2+ +2Fe 3+ +2H2O

[0024] MnO2+AsO3 3- +2H + =Mn 2+ +AsO4 3- +H2O,3Mn 2+ +2AsO4 3- =Mn3(AsO4)2(s)

[0025] Fe 3+ +AsO4 3- =FeAsO4(s)

[0026] 2FeAsO4+3Mn 2+ =Mn3(AsO4)2(s)+2Fe 3+

[0027] Fe 3+ +3H2O=Fe(OH)3(s)+3H +

[0028] 2Fe 3+ +4H2O=2FeO(OH)(s)+6H +

[0029] 2. Deep impurity removal: With the addition of zirconium hydroxide, the residual acid in the arsenic removal iron liquid is gradually consumed, the pH of the system rises, and a small amount of iron, aluminum, silicon, chromium, copper ions, etc. in the arsenic removal iron liquid are hydrolyzed to form hydroxide precipitates. Hydrolysis also generates hydrogen ions while generating precipitates. However, with the addition of zirconium hydroxide, the neutral to alkaline zirconium hydroxide consumes the hydrogen ions generated by hydrolysis, thereby promoting the forward direction of the hydrolysis reaction. As the pH of the system rises, part of the calcium ions in the arsenic removal iron liquid undergoes a double decomposition reaction with silicate ions to generate calcium silicate precipitates. Part of the calcium can also be removed through solid-liquid separation. With the addition of zirconium hydroxide, the main reactions that occur are as follows:

[0030] Cr 3+ +3H2O=Cr(OH)3(s)+3H +

[0031] Cu 2+ +2H2O=Cu(OH)2(s)+2H +

[0032] Al 3+ +3H2O=Al(OH)3(s)+3H +

[0033] SiO3 2- +Ca 2+ =CaSiO3(s)

[0034] In addition, zirconium hydroxide can undergo an ion exchange reaction with fluoride ions in the arsenic removal iron solution to form a zirconium-fluorine complex precipitate for removal. Experiments have found that zirconium hydroxide also has excellent adsorption properties for silicon, chromium (III), and chromium (VI) in the arsenic removal iron solution. In particular, the adsorption of chromium is non-selective. Both +3-valent and +6-valent chromium can be deeply removed by zirconium hydroxide without the need to pre-reducing the +6-valent chromium in the solution to convert it into +3-valent chromium that is more easily hydrolyzed. The verification of the removal effect of zirconium hydroxide on chromium in the solution is as follows:

[0035] In order to study the removal effect of zirconium hydroxide on chromium (III) and chromium (VI) in nickel sulfate solution system, 2 parts of 1L chromium removal pre-liquid (prepared by adding pure water to battery-grade nickel sulfate) were taken respectively, and then chromium (VI) was added separately. After the preparation, the chromium removal pre-liquid contained 0.056g / L of total chromium, all of which was Cr (VI), that is, 1# chromium removal pre-liquid was obtained. An excess amount of hydrogen peroxide with a mass concentration of 30% was added to another part of the same nickel sulfate solution (the amount of hydrogen peroxide was added according to the mass ratio of Cr to hydrogen peroxide of 1:60), and all the chromium in it was converted into Cr 3+ , and obtain 2# chromium removal pre-liquid. Then, zirconium hydroxide was added to 1# and 2# chromium removal pre-liquids respectively to investigate their adsorption effects on chromium of different valence states. The details are shown in Tables 1 and 2.

[0036] Table 1 Cr(VI) reduction conditions and chromium removal conditions by zirconium hydroxide

[0037]

[0038] Table 2 Chromium removal conditions and composition of the chromium removal solution (g / L)

[0039]

[0040] It can be seen from Tables 1 and 2 that the chromium in the nickel sulfate solution system, whether it is +3 valent or +6 valent, can be deeply removed by zirconium hydroxide. Zirconium hydroxide has no selectivity for the valence state of chromium therein. Therefore, when using zirconium hydroxide to remove chromium from the nickel sulfate solution system, there is no need to pre-reduce the +6 valent chromium into the more easily hydrolyzed +3 valent chromium. Moreover, when zirconium hydroxide is used to remove chromium, the temperature in the range of 20-95°C has no obvious effect on its chromium removal effect. The corresponding chromium removal effect can be achieved when the chromium removal time is more than 0.5h. The chromium removal process will not cause the loss of nickel in the solution. It can be seen that zirconium hydroxide is an excellent chromium removal agent.

[0041] The impurity removal slag obtained during the deep impurity removal in step (3) of the present invention is mainly composed of zirconium hydroxide, which adsorbs chromium and silicon dioxide, as well as a small amount of hydrolysis precipitates (copper hydroxide, aluminum hydroxide, chromium hydroxide, etc.), calcium silicate, and fluorine zirconium complex precipitates. Since zirconium hydroxide is used as an impurity remover, it achieves the purpose of deep impurity removal on aluminum, silicon, fluorine, chromium and copper in the nickel sulfate solution system through the multiple effects of neutralization, hydrolysis, adsorption and ion exchange, thereby reducing the burden on subsequent extraction and impurity removal. Since aluminum, silicon and part of calcium are removed, the formation of emulsions during subsequent extraction and purification can be reduced, and the extraction working environment can be improved. Since fluorine is removed, the corrosion of fluoride ions on equipment can be reduced, which is beneficial to extending the service life of the equipment. Since chromium is deeply removed, the nickel sulfate solution after impurity removal does not contain +6valent chromium and does not produce +6valent chromium wastewater. Since copper ions are removed in advance, copper is no longer extracted during P204 extraction and impurity removal, reducing the subsequent stripping process of copper in the organic load. Zirconium hydroxide also has the following advantages in the impurity removal process: it neither introduces impurity ions nor causes the loss of valuable metal nickel, and can achieve the effect of deep removal of multiple impurities and reduce the burden of subsequent extraction.

[0042] When zirconium hydroxide is added to the arsenic-removing iron liquid for deep impurity removal, it is best to control the pH at 4.5-6.0. When the pH is lower than 4.5, the removal of aluminum, chromium and silicon is not complete. When the pH is higher than 6.0, the amount of zirconium hydroxide used is large and the impurity removal effect is not significantly improved. At the same time, due to the introduction of excessive zirconium hydroxide, the valuable metal nickel will be partially precipitated and converted into nickel hydroxide and enter the impurity removal slag, which is not conducive to nickel recovery. When the pH is 4.5-6.0, the impurity removal effect is similar, and the deep impurity removal effect can be achieved. Therefore, the pH should be controlled at 4.5-6.0 during deep impurity removal in step (3).

[0043] 3. Extraction and purification: After arsenic and iron removal, and deep impurity removal of zirconium hydroxide, the main impurities in the solution are only zinc, calcium, manganese, cobalt, and magnesium. Zinc, calcium, and manganese can be removed by P204 extraction. The main impurities in the obtained P204 raffinate are cobalt and magnesium, which are then removed by P507 or similar extractants (such as C272). After the above process, all impurities are separated to obtain a refined nickel sulfate solution, which can be further deoiled, evaporated and crystallized to produce battery-grade nickel sulfate crystals. It can also be used to produce electrolytic nickel and nickel-cobalt-manganese ternary precursors.

[0044] The present invention has no strict requirements on the amount of water added during the dissolution process of step (1). When the amount of water added is less, volume expansion can be reduced. Water can be added according to the nickel concentration of 80-120g / L when the nickel in the high-mixed nickel sulfate is completely dissolved. High-mixed nickel sulfate is an acidic substance. The pH value of the high-mixed nickel liquid obtained after dissolution is 0.5-2.5. Under this pH condition, the iron and arsenic in the high-mixed nickel liquid exist as free ions and are generated without precipitation. This pH value can ensure that the foreign ions in the high-mixed nickel sulfate are completely dissolved first, and then further impurity removal is performed on it. Therefore, it is advisable that the pH value of the high-mixed nickel liquid is controlled at 0.5-2.5.

[0045] The present invention has no strict requirements on the impurity removal temperature in step (3). The deep impurity removal effect can be achieved at room temperature or when heated. When the temperature is within the range of 20-95°C and other conditions are the same, the impurity removal effect is similar. The impurity removal time can be more than 0.5h. In order to improve the impurity removal efficiency, the impurity removal time is preferably controlled within 4h.

[0046] The present invention has no strict requirements on the volume concentration of the extractant. When the concentration of the extractant is too high, the viscosity is large, which is not conducive to phase separation after extraction. When the concentration is too low, it is not conducive to improving the extraction efficiency. The volume concentration of P204 is preferably controlled at 20-25%, and the volume concentration of P507 or C272 is preferably controlled at 15-20%. A single-stage extraction time of more than 10 minutes can achieve the effect of extracting the corresponding impurities. In order to improve work efficiency, the extraction time is controlled at 10-20 minutes.

[0047] In order to reuse the impurity-laden P204, P507, or C272 extractants, the impurity ions carried must be stripped to achieve the purpose of regeneration and recycling of the extractants. The main impurities in the P204 organic phase are manganese, zinc, and calcium, which can be stripped with dilute sulfuric acid. To improve the nickel recovery rate, the loaded organic phase can be washed with pure water before stripping the impurities to remove the nickel carried by the loaded organic phase. The resulting nickel washing solution can be returned to the extraction stock solution and sulfuric acid is then added to strip the loaded impurities. Specifically:

[0048] (1) The loaded organic phase I is first washed with pure water for nickel, and then manganese and calcium are stripped with 1.5-2.5N dilute sulfuric acid, and the pH of the aqueous phase is controlled to be 2.0-2.5 to obtain a stripped liquid containing manganese and calcium and a loaded organic phase II. 1.5-2.5N dilute sulfuric acid is further added to the loaded organic phase II to strip zinc, and the pH of the aqueous phase is controlled to be 1.0-1.8 to obtain a stripped liquid containing zinc and a loaded organic phase III. The loaded organic phase III is the regenerated P204, which can be returned for extraction and impurity removal. In the above-mentioned stripping process, if the pH value of one-stage stripping is higher than 2.5, the stripping of manganese and calcium will not be thorough, so that the manganese and calcium remaining in the loaded organic phase II enter the liquid after zinc stripping, and the separation of manganese and zinc is not thorough. If the pH value of one-stage stripping is lower than 2.0, excessive acidity will cause zinc to be partially stripped first, causing a large amount of zinc to enter the liquid after manganese and calcium stripping, and the separation of manganese and zinc is also not thorough. During the second-stage stripping, if the pH value is higher than 1.8, the stripping of zinc is not thorough, and the extraction effect when the extractant is used again is reduced. The pH value is lower than 1.0, and the residual acid of the liquid after zinc stripping is higher, causing the consumption of the neutralizing agent to increase during the treatment of the liquid after zinc stripping, which is not conducive to cost saving. There is no strict requirement for the sulfuric acid concentration used in the above-mentioned stripping process, as long as it is conducive to operation (conveniently controlling the pH value of each section during stripping).

[0049] (2) The loaded organic phase IV is first washed with pure water for nickel, and then the magnesium is stripped with 0.5-1.5N dilute sulfuric acid, and the pH of the aqueous phase is controlled to be 3.5-4.5 to obtain a stripped liquid containing magnesium and a loaded organic phase V. 1.5-2.5N dilute sulfuric acid is further added to the loaded organic phase V to strip cobalt, and the pH of the aqueous phase is controlled to be 2.0-2.5 to obtain a stripped liquid containing cobalt and a loaded organic phase VI. The loaded organic phase VI is the regenerated P507 or the regenerated C272, which can be returned for use in extracting cobalt and magnesium. In the above-mentioned stripping process, if the pH value is higher than 4.5 during the stripping of magnesium, the stripping of magnesium is not thorough, thereby causing the remaining magnesium in the loaded organic phase V to enter the cobalt-containing stripping liquid, and the separation of magnesium and cobalt is not thorough. If the pH value is lower than 3.5 during the stripping of magnesium, the excessive acidity will cause the cobalt to be partially stripped first, causing the cobalt to enter the magnesium-containing stripping liquid, which also causes the separation of magnesium and cobalt to be incomplete. If the pH value is higher than 2.5 during the stripping of cobalt, the stripping of cobalt will not be thorough, reducing the extraction effect when the extractant is used again. If the pH value is lower than 2.0, the residual acid in the cobalt-containing stripping liquid is high, which will lead to an increase in the amount of neutralizer consumed when the cobalt-containing stripping liquid is treated, which is not conducive to cost saving. There is no strict requirement for the concentration of sulfuric acid used for stripping, as long as it is conducive to operation (conveniently controlling the pH value of each section during stripping).

[0050] 4. Washing the impurity removal residue with water removes the entrained nickel sulfate solution. The resulting impurity removal residue wash solution is primarily nickel sulfate, with low levels of other impurities. This solution can be used for subsequent sodium washing of zirconium hydroxide, saving water for sodium washing. Adding sulfuric acid for desorption desorbs the hydrolyzed hydroxide precipitate and the silicon adsorbed by the zirconium hydroxide. During the desorption process, the hydroxide reacts with the sulfuric acid, converting it into sulfate, and the silicon into water-soluble silicon, which enters the first desorption solution. After the first desorption, the chromium and fluorine in the first desorption residue are not completely desorbed. Therefore, an alkaline reagent is added for a second desorption to desorb the adsorbed chromium and fluorine, converting the fluorine in the fluorine-zirconium complex into fluoride ions. Meanwhile, the remaining chromium from the sulfuric acid desorption process is completely desorbed. After one sulfuric acid desorption and one liquid caustic soda desorption, the impurities adsorbed in the second desorption residue are essentially desorbed. The zirconium hydroxide after the sodium wash is alkaline and has the same chemical properties as the first zirconium hydroxide, making it suitable for further impurity removal in nickel sulfate solution. During the sulfuric acid desorption process, the pH should be controlled at 1.0-1.5 to completely desorb the hydrolysis products and adsorbates from the impurity removal process. If the pH is lower than 1.0, complete desorption will result in a large amount of zirconium dissolution. If the pH is higher than 1.5, desorption will be incomplete. Therefore, it is better to control the pH of sulfuric acid desorption at 1.0-1.5. During the liquid alkali desorption process, if the pH is lower than 10, fluorine desorption will be incomplete. If the pH is higher than 12, a large amount of sodium ions will be introduced, increasing the burden of subsequent sodium washing. Therefore, it is best to control the pH of the second desorption process at 10-12.

[0051] There is no strict requirement for the concentration of sulfuric acid and liquid caustic soda used in the desorption process, as long as the pH can be easily controlled. The commonly used sulfuric acid mass concentration of 10%-98% and liquid caustic soda mass concentration of 5%-50% in industry can be used in the present invention.

[0052] The process of the present invention is as follows Figure 1 shown.

[0053] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0054] (1) By adding an iron-containing neutralizer to the high-nickel solution to remove arsenic iron by neutralization hydrolysis or goethite method, the iron and arsenic can be removed simultaneously;

[0055] (2) Zirconium hydroxide is an amphoteric hydroxide with a large specific surface area. When zirconium hydroxide is added to the arsenic removal iron solution, the impurities aluminum, silicon, chromium, copper, and fluoride ions in the solution are deeply removed simultaneously through the multiple effects of neutralization and hydrolysis, adsorption of zirconium hydroxide, and ion exchange, which can greatly reduce the burden of subsequent extraction and impurity removal;

[0056] (3) Refined nickel sulfate solution is obtained by dissolving, removing arsenic and iron, deep impurity removal, and extraction purification, thereby achieving the refining of crude nickel sulfate. The prepared refined nickel sulfate solution can be used to produce battery-grade nickel sulfate crystals, or to produce electrolytic nickel, or to produce nickel-cobalt-manganese ternary precursors after degreasing.

[0057] (4) The extraction agent can be recycled through washing, back-extraction and other processes.

[0058] (5) The zirconium hydroxide can be recycled by washing and desorbing the removed zirconium hydroxide twice and washing with sodium. The second desorption residue is washed with the removed residue washing water to save washing water. Sodium sulfate can be produced after nickel is recovered from the sodium washing water. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0060] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0061] Example 1

[0062] (1) Dissolution and removal of arsenic and iron

[0063] Take 500 g of 1# high-mix nickel sulfate (the composition of high-mix nickel sulfate is shown in Table 3), dissolve it in water at a liquid-solid mass ratio of 2.14:1 at room temperature, and dissolve it completely after 15 minutes. The nickel concentration in the obtained high-mix nickel liquid component is 80.12 g / L, and the pH is 1.02. After heating the high-mix nickel liquid to 60°C, nickel hydroxide is added (its amount is controlled according to the end point pH = 3.50). After reacting for 4 hours, the solid-liquid separation is performed to obtain 1# arsenic removal iron liquid and 1# arsenic slag. The arsenic concentration in the arsenic removal iron liquid is reduced to 0.3 mg / L, and the iron concentration is 1.8 mg / L. Except that the nickel concentration is slightly increased due to the introduction of nickel hydroxide, the other components are basically unchanged. The nickel hydroxide composition is shown in Table 4, the high-mix nickel liquid composition is shown in Table 5, and the arsenic removal iron liquid composition is shown in Table 6.

[0064] (2) Deep impurity removal

[0065] 900 ml of 1# arsenic-removed iron solution was added to it at 20°C (the amount was controlled to achieve an endpoint pH of 6.00). The total reaction time was 4 hours. After completion of the reaction, solid-liquid separation was performed to obtain 1# impurity-removed solution and 1# impurity-removed slag. The arsenic and iron concentrations in the impurity-removed solution were both reduced to 0.1 mg / L. The concentrations of other major impurities were as follows: aluminum 0.5 mg / L, SiO2 0.1 mg / L, fluorine 25 mg / L, chromium 0.2 mg / L, and copper 5.1 mg / L. The remaining components did not change much. The major impurity contents are shown in Table 7.

[0066] (3) Desorption of impurities

[0067] Take 1# impurity removal residue and add water to make pulp according to the liquid-solid mass ratio of 3:1, wash once at room temperature for 0.5h, separate the solid and liquid to obtain 1# impurity removal washing liquid, and keep the washing liquid for subsequent sodium washing. Under room temperature conditions, continue to add water to the washed impurity removal residue at a liquid-solid mass ratio of 3:1 to make pulp, and add dilute sulfuric acid with a mass concentration of 10% to adjust the pulp pH to 1.50, perform the first desorption, the desorption time is 1h, after the desorption is completed, solid-liquid separation is performed to obtain 1# first desorption residue and 1# first desorption liquid, add water to the 1# first desorption residue at a liquid-solid mass ratio of 3:1 to make pulp, then add liquid alkali with a mass concentration of 50% to adjust the pulp pH to 10.00, perform the second desorption, the desorption time is 1h, after the second desorption is completed, solid-liquid separation is performed to obtain second desorption residue and second desorption liquid. Under normal temperature conditions, the 1# second desorption slag is continued to be washed with sodium using the aforementioned impurity removal slag washing water (liquid-solid mass ratio 3:1), the washing time is 0.5h, and the washing stage is 1, to obtain 1# sodium washing water and 1# regenerated zirconium hydroxide. The 1# regenerated zirconium hydroxide can be used again in the deep impurity removal process, and the impurity removal effect is equivalent to that of the zirconium hydroxide used for the first time.

[0068] (4) Extraction and purification

[0069] After precise filtration of the 1# impurity-removed liquid, add P204 nickel soap with a volume concentration of 20% to extract impurities (P204 blank organic is first diluted with kerosene to a volume concentration of 20%, and then a liquid alkali with a mass concentration of 30% is added according to a saponification rate of 50% to perform sodium soap. After the sodium soap is completed, continue to add low-impurity nickel sulfate solution to perform nickel soap. The nickel soap time is 15min, the number of stages is 2, and the control phase is 1:1. The purpose is to wash off the sodium introduced by the sodium soap so as not to increase the sodium ion concentration in the nickel sulfate crystal product). The temperature was 25°C, the single-stage extraction time was 20 min, the phase ratio was 1:5, and the extraction method was countercurrent extraction for 6 stages. After the extraction, the phases were separated to obtain 1# P204 raffinate and 1# loaded organic phase I. The copper concentration in the raffinate was further reduced to 0.2 mg / L, and the concentrations of the other extracted metals were reduced to 2.2 mg / L calcium, 0.8 mg / L manganese, and 1.5 mg / L zinc, respectively. Except for the slight increase in the nickel concentration of the raffinate due to the use of nickel soap, the concentrations of other elements remained basically unchanged. The specific components are shown in Table 8. P507 nickel soap with a volume concentration of 15% (the saponification method is the same as that of P204 nickel soap) was continued to be added to the 1#P204 raffinate to extract cobalt and magnesium. The temperature for extracting cobalt and magnesium was 25°C, the single-stage extraction time was 20 min, the phase ratio was 1:3, and the extraction method was 6-stage countercurrent extraction. After the extraction was completed, the phases were separated to obtain 1# refined nickel sulfate solution and 1#P507 loaded organic phase. The cobalt and magnesium concentrations in the refined nickel sulfate solution were reduced to 0.2 mg / L for cobalt and 1.2 mg / L for magnesium, respectively. Except that the nickel concentration was slightly higher than that of the P204 raffinate due to the use of nickel soap, the concentrations of other elements remained basically unchanged. The specific components are shown in Table 9.

[0070] (5) Regeneration of organic matter

[0071] Wash the 1# loaded organic phase I twice at room temperature, then add 1.5N dilute sulfuric acid to the washed P204 organic phase, control the pH of the stripping solution to 2.00 for stripping manganese and calcium, and continue stripping zinc with 1.5N dilute sulfuric acid for the P204 after stripping manganese and calcium, and control the pH of the stripping solution to 1.51. After stripping zinc, regenerated P204 can be returned for extraction and impurity removal. Wash the 1# P507 loaded organic phase twice at room temperature, then strip magnesium with 0.5N dilute sulfuric acid for the washed P507 (control the pH of the stripping solution to 3.49), and continue stripping cobalt with 1.5N dilute sulfuric acid for the organic phase after stripping magnesium (control the pH of the stripping solution to 2.06). After stripping cobalt, regenerated P507 can be returned for extraction of cobalt and magnesium.

[0072] (6) Oil removal and evaporation crystallization

[0073] The 1# refined nickel sulfate solution was deoiled with activated carbon to obtain 1# deoiled liquid. During the deoiling process, the flow rate of the refined nickel sulfate solution was controlled to be 5 BV / h and the temperature was kept at room temperature. The obtained deoiled liquid had an oil content of 3.55 mg / L. The deoiled liquid was evaporated and crystallized to obtain 1# nickel sulfate crystals, the composition of which is shown in Table 10.

[0074] Example 2

[0075] (1) Dissolution and removal of arsenic and iron

[0076] Take 5 kg of 2# high-mix nickel sulfate (the composition of high-mix nickel sulfate is shown in Table 3), dissolve it in water at a liquid-solid mass ratio of 1.28:1 at room temperature, and dissolve it completely after 20 minutes. The nickel concentration in the obtained high-mix nickel liquid component is 119.23 g / L, and the pH is 2.50. After heating the high-mix nickel liquid to 80°C, nickel hydroxide is added (its amount is controlled according to the end point pH 3.26). After reacting for 2 hours, the solid-liquid separation is performed to obtain 2# arsenic removal iron liquid and 2# arsenic slag. The arsenic concentration in the arsenic removal iron liquid is reduced to 0.1 mg / L, and the iron concentration is 2.5 mg / L. Except that the nickel concentration is slightly increased due to the introduction of nickel hydroxide, the other components are basically unchanged. The nickel hydroxide composition is shown in Table 4, the high-mix nickel liquid composition is shown in Table 5, and the arsenic removal iron liquid composition is shown in Table 6.

[0077] (2) Deep impurity removal

[0078] 8 L of 2# arsenic-removed iron solution were added to it at 60°C (the amount was controlled to achieve an endpoint pH of 5.51). The total reaction time was 2 hours. After completion of the reaction, solid-liquid separation was performed to obtain 2# impurity-removed solution and 2# impurity-removed slag. The arsenic and iron concentrations in the impurity-removed solution were further reduced to 0.1 mg / L. The concentrations of other major impurities were as follows: aluminum 0.8 mg / L, SiO2 2.0 mg / L, fluorine 110 mg / L, chromium 0.3 mg / L, and copper 1.6 mg / L. The remaining components did not change much. The major impurity contents are shown in Table 7.

[0079] (3) Desorption of impurities

[0080] Take 2# impurity removal residue and add water to make pulp according to the liquid-solid mass ratio of 2:1, wash once at 60℃ for 1h, separate the solid and liquid to obtain 2# impurity removal washing liquid, and keep the washing liquid for subsequent sodium washing. Continue to add water to the washed impurity removal residue at the liquid-solid mass ratio of 2:1 to make pulp, and add dilute sulfuric acid with a mass concentration of 50% to adjust the slurry pH to 1.00, perform the first desorption, the desorption time is 4h, after the desorption is completed, the solid-liquid separation is performed to obtain 2# first desorption residue and 2# first desorption liquid, add water to the 2# first desorption residue at the liquid-solid mass ratio of 2:1 to make pulp, and then add liquid alkali with a mass concentration of 30% to adjust the slurry pH to 12.02, perform the second desorption, the desorption time is 4h, after the second desorption is completed, the solid-liquid separation is performed to obtain the second desorption residue and the second desorption liquid. The 2# second desorption residue is washed with sodium using the aforementioned impurity removal residue washing water (liquid-to-solid mass ratio is 2:1), the washing time is 1 hour, and the washing stage is 1, to obtain 2# sodium washing water and 2# regenerated zirconium hydroxide. The 2# regenerated zirconium hydroxide can be used again in the deep impurity removal process, and the impurity removal effect is equivalent to that of the zirconium hydroxide used for the first time.

[0081] (4) Extraction and purification

[0082] After the 2# impurity-removed liquid is precisely filtered, P204 nickel soap with a volume concentration of 25% is added to extract impurities (the P204 blank organic is first diluted with kerosene to a volume concentration of 25%, and then a liquid alkali with a mass concentration of 10% is added according to a saponification rate of 45% to perform sodium soap. After the sodium soap is completed, low-impurity nickel sulfate solution is added thereto to perform nickel soap. The nickel soap time is 10 minutes, the number of stages is 2, and the control phase ratio is 1:1. The purpose is to wash off the sodium introduced by the sodium soap so as not to increase the sodium ion concentration in the nickel sulfate crystal product). The temperature during the extraction is The temperature was 35°C, the single-stage extraction time was 15 min, the phase ratio was 1:1, and the extraction method was cross-current extraction for 2 stages. After the extraction, the phases were separated to obtain 2#P204 raffinate and 2# loaded organic phase I. The copper concentration in the P204 raffinate was further reduced to 0.6 mg / L, and the concentrations of the other extracted metals were reduced to 0.1 mg / L calcium, 1.3 mg / L manganese, and 1.0 mg / L zinc, respectively. Except for the slight increase in the nickel concentration of the raffinate due to the use of nickel soap, the concentrations of other elements remained basically unchanged. The specific components are shown in Table 8. P507 nickel soap with a volume concentration of 20% (the saponification method is the same as that of P204 nickel soap) was continued to be added to the 2#P204 raffinate to extract cobalt and magnesium. The temperature for extracting cobalt and magnesium was 35°C, the single-stage extraction time was 15 min, the phase ratio was 1:2, and the extraction method was 2-stage cross-current extraction. After the extraction was completed, the phases were separated to obtain 2# refined nickel sulfate solution and 2#P507 loaded organic phase. The cobalt and magnesium concentrations in the 2# refined nickel sulfate solution were reduced to 1.0 mg / L for cobalt and 1.0 mg / L for magnesium, respectively. Except that the nickel concentration was slightly higher than that of the P204 raffinate due to the use of nickel soap, the concentrations of other elements remained basically unchanged. The specific components are shown in Table 7.

[0083] (7) Regeneration of organic matter

[0084] The 2# loaded organic phase I was washed twice at room temperature, and then 2.5N dilute sulfuric acid was added to the washed P204 organic phase, and the pH of the stripping solution was controlled to be 2.50 for stripping manganese and calcium. After stripping manganese and calcium, the P204 was stripped with 2.5N dilute sulfuric acid to strip zinc, and the pH of the stripping solution was controlled to be 1.81. After stripping zinc, the regenerated P204 was returned for extraction and impurity removal. The 2# P507 loaded organic phase was washed twice at room temperature, and then the washed P507 was stripped with 1.0N dilute sulfuric acid to strip magnesium (control the pH of the stripping solution to be 4.52). After stripping magnesium, the organic phase was stripped with 2.5N dilute sulfuric acid to strip cobalt (control the pH of the stripping solution to be 2.48). After stripping cobalt, the regenerated P507 was returned for extraction of cobalt and magnesium.

[0085] (8) Oil removal and evaporation crystallization

[0086] The 2# refined nickel sulfate solution was deoiled with activated carbon to obtain 2# deoiled liquid. During the deoiling process, the flow rate of the refined nickel sulfate solution was controlled to be 6 BV / h and the temperature was kept at room temperature. The oil content of the obtained deoiled liquid was 5.00 mg / L. The deoiled liquid was evaporated and crystallized to obtain 2# nickel sulfate crystals, the composition of which is shown in Table 10.

[0087] Example 3

[0088] (1) Dissolution and removal of arsenic and iron

[0089] 100 kg of 3# high-mix nickel sulfate (the composition of high-mix nickel sulfate is shown in Table 3) was taken and dissolved in water at a liquid-solid mass ratio of 1.70:1 under normal temperature conditions. The solution was completely dissolved after 30 minutes. The nickel concentration in the obtained high-mix nickel liquid component was 99.81 g / L and the pH was 0.50. The high-mix nickel liquid was heated to 95°C and nickel hydroxide was added (the amount was controlled according to the end point pH 3.00). After reacting for 1 hour, the solid-liquid separation was performed to obtain 3# arsenic removal iron liquid and 3# arsenic slag. The arsenic concentration in the arsenic removal iron liquid was reduced to 0.1 mg / L, and the iron concentration was 1.0 mg / L. Except that the nickel concentration was slightly increased due to the introduction of nickel hydroxide, the other components were basically unchanged. The nickel hydroxide composition is shown in Table 4, the high-mix nickel liquid composition is shown in Table 5, and the arsenic removal iron liquid composition is shown in Table 6.

[0090] (2) Deep impurity removal

[0091] 208 L of 3# arsenic-removed iron liquid were added to it at 95°C (the amount was controlled to achieve an endpoint pH of 4.50). The total reaction time was 0.5 h. After the reaction, solid-liquid separation was performed to obtain 3# impurity-removed liquid and 3# impurity-removed slag. The arsenic and iron concentrations in the impurity-removed liquid were further reduced to 0.1 mg / L. The concentrations of other major impurities were as follows: aluminum 1.3 mg / L, SiO2 5.0 mg / L, fluorine 20 mg / L, chromium 0.3 mg / L, and copper 0.4 mg / L. The remaining components did not change much. The specific contents of major impurities are shown in Table 7.

[0092] (3) Desorption of impurities

[0093] Take 3# impurity removal residue and add water to make pulp according to the liquid-solid mass ratio of 1:1, wash twice at 95℃ for 1h, separate the solid and liquid to obtain 3# impurity removal residue washing liquid, and keep the washing liquid for subsequent sodium washing. Continue to add water to the washed impurity removal residue at the liquid-solid mass ratio of 1:1 to make pulp, and add dilute sulfuric acid with a mass concentration of 98% to adjust the pulp pH to 1.27, perform the first desorption, the desorption time is 2h, after the desorption is completed, the solid-liquid separation is performed to obtain 3# first desorption residue and 3# first desorption liquid, add water to the 3# first desorption residue at the liquid-solid mass ratio of 1:1 to make pulp, then add liquid alkali with a mass concentration of 5% to adjust the pulp pH to 11.37, perform the second desorption, the desorption time is 2h, after the second desorption is completed, the solid-liquid separation is performed to obtain the second desorption residue and the second desorption liquid. The 3# second desorption residue is washed with sodium using the aforementioned impurity removal residue washing water (liquid-to-solid mass ratio is 1:1), the washing time is 1 hour, and the washing stage is 1, to obtain 3# sodium washing water and 3# regenerated zirconium hydroxide. The 3# regenerated zirconium hydroxide can be used again in the deep impurity removal process, and the impurity removal effect is equivalent to that of the zirconium hydroxide used for the first time.

[0094] (4) Extraction and purification

[0095] After the 3# impurity-removed liquid is precisely filtered, P204 nickel soap with a volume concentration of 22% is added for extraction (the P204 blank organic is first diluted with kerosene to a volume concentration of 22%, and then a liquid alkali with a mass concentration of 50% is added according to a saponification rate of 55% to perform sodium soap. After the sodium soap is completed, low-impurity nickel sulfate solution is added thereto for nickel soap. The nickel soap time is 20 minutes, the number of stages is 2, and the control phase ratio is 1:1. The purpose is to wash off the sodium introduced by the sodium soap so as not to increase the sodium ion concentration in the nickel sulfate crystal product). The temperature during extraction is The temperature was 40℃, the single-stage extraction time was 10min, the phase ratio was 1:3, and the extraction method was countercurrent extraction for 4 stages. After the extraction, the phases were separated to obtain 3#P204 raffinate and 3# loaded organic phase I. The copper concentration in the P204 raffinate was further reduced to 0.1mg / L, and the concentrations of the other extracted metals were reduced to 2.5mg / L calcium, 0.5mg / L manganese, and 0.5mg / L zinc, respectively. Except for the slight increase in the nickel concentration of the raffinate due to the use of nickel soap, the concentrations of other elements remained basically unchanged. The specific components are shown in Table 8. C272 nickel soap with a volume concentration of 18% (the saponification method is the same as that of P204 nickel soap) was continued to be added to the 3#P204 raffinate to extract cobalt and magnesium. The temperature for extracting cobalt and magnesium was 40°C, the single-stage extraction time was 10 min, the phase ratio was 1:3, and the extraction method was 4-stage countercurrent extraction. After the extraction was completed, the phases were separated to obtain 3# refined nickel sulfate solution and 3#C272 loaded organic phase. The cobalt and magnesium concentrations in the refined nickel sulfate solution were reduced to 0.3 mg / L for cobalt and 2.0 mg / L for magnesium, respectively. Except that the nickel concentration was slightly higher than that of the P204 raffinate due to the use of nickel soap, the concentrations of other elements remained basically unchanged. The specific components are shown in Table 9.

[0096] (5) Regeneration of organic matter

[0097] Wash the 3# loaded organic phase I twice at room temperature, then add 2.0N dilute sulfuric acid to the washed P204 organic phase, control the pH of the stripping solution to 2.26 for stripping manganese and calcium, and continue stripping zinc with 2.0N dilute sulfuric acid on the P204 after stripping manganese and calcium, control the pH of the stripping solution to 1.03, and obtain regenerated P204 after stripping zinc, which can be returned for extraction and impurity removal. Wash the 3# C272 loaded organic phase twice at room temperature, then strip magnesium with 0.8N dilute sulfuric acid on the washed C272 (control the pH of the stripping solution to 4.05), and continue stripping cobalt with 2.26N dilute sulfuric acid on the organic phase after stripping magnesium (control the pH of the stripping solution to 2.33), and obtain regenerated C272 after stripping cobalt, which can be returned for extraction of cobalt and magnesium.

[0098] (6) Oil removal and evaporation crystallization

[0099] The 3# refined nickel sulfate solution was deoiled with activated carbon to obtain 3# deoiled liquid. During the deoiling process, the flow rate of the refined nickel sulfate solution was controlled to be 3 BV / h and the temperature was kept at room temperature. The oil content of the obtained deoiled liquid was 2.63 mg / L. The deoiled liquid was evaporated and crystallized to obtain 3# nickel sulfate crystals, the composition of which is shown in Table 10.

[0100] Table 3 Main components of high-mix nickel sulfate natural base / %

[0101] serial number Ni As Fe Al <![CDATA[SiO2]]> F Cr Cu Ca Mn Zn Co Mg 1 20.43 0.19 0.44 0.012 0.019 0.19 0.021 0.36 0.083 0.023 0.26 0.0083 0.16 2 20.15 0.80 1.20 0.068 0.035 0.35 0.056 0.82 0.0055 0.13 0.58 0.12 0.042 3 21.06 2.39 1.90 0.11 0.10 0.026 0.11 1.91 0.14 0.062 0.11 0.071 0.28

[0102] Table 4 Neutralizing agent nickel hydroxide natural base composition / %

[0103] Ni Co Mn 26.60 2.10 1.50

[0104] Table 5 Main components of high-impurity nickel solution (g / L)

[0105] Example Ni As Fe Al <![CDATA[SiO2]]> F Cr Cu Ca Mn Zn Co Mg Na 1 80.12 0.75 1.73 0.047 0.075 0.75 0.082 1.41 0.33 0.090 1.02 0.033 0.63 0.019 2 119.23 4.73 7.10 0.40 0.21 2.07 0.33 4.85 0.033 0.77 3.43 0.71 0.25 0.019 3 99.81 11.33 9.00 0.52 0.47 0.12 0.52 9.05 0.66 0.29 0.52 0.34 1.33 0.026

[0106] Table 6 Main components of the liquid after arsenic and iron removal (g / L)

[0107] Example Ni As Fe Al <![CDATA[SiO2]]> F Cr Cu 1 86.12 0.0003 0.0018 0.045 0.064 0.75 0.13 1.41 2 123.2 0.0001 0.0025 0.40 0.21 2.07 0.33 4.85 3 105.7 0.0001 0.0010 0.52 0.47 0.12 0.52 9.05

[0108] Table 7 Main impurity components of the liquid after impurity removal (g / L)

[0109] Example As Fe Al <![CDATA[SiO2]]> F Cr Cu Ca Mn Zn Co Mg 1 0.0001 0.0001 0.0005 0.0001 0.025 0.0002 0.0051 0.33 0.0090 1.02 0.033 0.63 2 0.0001 0.0001 0.0008 0.0020 0.11 0.0003 0.0016 0.033 0.77 3.43 0.71 0.25 3 0.0001 0.0001 0.0013 0.0050 0.020 0.0003 0.0004 0.664 0.29 0.52 0.34 1.33

[0110] Table 8 Main components of P204 raffinate (g / L)

[0111]

[0112] Table 9 Main components of refined nickel sulfate solution (g / L)

[0113]

[0114] Table 10 Main components of battery grade nickel sulfate / %

[0115]

[0116] In the above embodiment, the main components of the washing liquid produced by washing the 1#-3# impurity removal residues, desorbing them twice, and washing them with sodium once are shown in Table 11.

[0117] Table 11 Main components of the solution during the slag removal process (g / L)

[0118]

[0119] The above description is a detailed description of the preferred embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. Any equivalent changes or modifications completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for refining high-impregnation nickel sulfate, characterized in that: The following steps are involved: (1) dissolving: adding water to dissolve high-mix nickel sulfate to obtain a high-mix nickel solution; the impurities in the high-mix nickel sulfate include arsenic, iron, aluminum, silicon, fluorine, chromium, copper, calcium, manganese, zinc, cobalt, and magnesium; the high-mix nickel solution has a nickel ion concentration of 80-120 g / L and a pH of 0.5-2.5; (2) Arsenic and iron removal: The high-impregnation nickel solution is heated to 60-95°C, a neutralizer is added to adjust the pH of the system to 3.0-3.5, and the solid-liquid separation is performed to obtain arsenic slag and arsenic-removed iron solution; (3) Deep impurity removal: zirconium hydroxide is added to the arsenic removal iron liquid to adjust the pH of the system to 4.5-6.0, and the solid-liquid separation is performed to obtain impurity removal slag and impurity removal liquid; wherein the impurity removal temperature is 20-95°C and the impurity removal time is 0.5-4h; (4) Extraction and purification: After precise filtration of the impurity-removed liquid, P204 is added to extract and remove manganese, calcium, and zinc, and the phases are separated to obtain a P204 raffinate and a loaded organic phase I; P507 or C272 is added to the P204 raffinate to extract and remove cobalt and magnesium, and the phases are separated to obtain a refined nickel sulfate solution and a loaded organic phase IV.

2. The method for refining high-impregnated nickel sulfate according to claim 1, wherein: In step (2), the neutralizing agent is nickel hydroxide.

3. The method for refining high-mix nickel sulfate according to claim 1, wherein: In step (4), the volume concentration of P204 is 20-25%, the volume concentration of P507 is 15-20%, and the single-stage extraction time is 10-20 minutes.

4. The method for refining high-mix nickel sulfate according to claim 1, wherein: The following steps are also included: The refined nickel sulfate solution in step (4) is deoiled with activated carbon, evaporated and crystallized to obtain battery-grade nickel sulfate crystals.

5. The method for refining high-impregnated nickel sulfate according to claim 1, wherein: The following steps are also included: The loaded organic phase I is first washed with nickel with pure water, and then dilute sulfuric acid is added for back extraction and phase separation, and the pH of the aqueous phase is controlled to be 2.0-2.5 to obtain a manganese-calcium back extraction liquid and a loaded organic phase II. Dilute sulfuric acid is then added to the loaded organic phase II for back extraction and phase separation, and the pH of the aqueous phase is controlled to be 1.0-1.8 to obtain a zinc-containing back extraction liquid and a loaded organic phase III. The loaded organic phase III is the regenerated P204, which can be returned to step (4) for use.

6. The method for refining high-impregnated nickel sulfate according to claim 1, wherein: The following steps are also included: The loaded organic phase IV is first washed with nickel with pure water, and then dilute sulfuric acid is added for back extraction and phase separation, and the pH of the aqueous phase is controlled to be 3.5-4.5 to obtain a magnesium-containing back extraction liquid and a loaded organic phase V. Dilute sulfuric acid is then added to the loaded organic phase V for back extraction and phase separation, and the pH of the aqueous phase is controlled to be 2.0-2.5 to obtain a cobalt-containing back extraction liquid and a loaded organic phase VI. The loaded organic phase VI is the regenerated P507 or regenerated C272, which can be returned to step (4) for use.

7. The method for refining high-impregnated nickel sulfate according to claim 1, wherein: The following steps are also included: The impurity removal slag is washed with water to remove the nickel sulfate solution carried by the impurity removal slag, and a impurity removal slag washing liquid is obtained. Sulfuric acid is added to the impurity removal slag washing liquid to adjust the pH to 1.0-1.5 for desorption to obtain a first desorption liquid and a first desorption slag. Liquid alkali is added to the first desorption slag to adjust the pH to 10-12 to obtain a second desorption liquid and a second desorption slag. The second desorption slag is washed with sodium with the impurity removal slag washing liquid to obtain regenerated zirconium hydroxide, which can be returned to step (3) for use.

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