Method for purifying and removing impurities from a crude nickel-cobalt-manganese sulfate solution

Abstract

The application provides a purification and impurity removal method of a crude nickel-cobalt-manganese sulfate solution, and comprises the following steps: (1) adding thiosulfate to the crude nickel-cobalt-manganese sulfate solution to remove copper; (2) adding phosphate and adjusting the pH value to remove titanium, iron and aluminum; (3) adding iron sulfate and adjusting the pH value to remove phosphorus and silicon; (4) adding a bismuth agent and adjusting the pH value to remove chlorine; (5) adding a fluorine agent to remove calcium and magnesium; and (6) adding an ice rock mineral adsorbent to remove fluorine. The method can efficiently remove iron, aluminum, copper, fluorine, phosphorus, titanium, calcium, magnesium, chlorine, silicon and other elements from the crude nickel-cobalt-manganese sulfate solution, and the loss of main metals is low; the high-purity nickel-cobalt-manganese sulfate solution prepared can directly meet the requirements of a battery preparation grade precursor solution, the process is simple, the operation difficulty is low, and the industrialized production can be easily realized, and the method overcomes the shortcomings of the current high-purity nickel-cobalt-manganese sulfate solution preparation method.

Description

Technical Field

[0001] The invention belongs to the field of battery metal solution purification and regeneration, and in particular relates to a method for purifying and removing impurities from sulfuric acid-based battery metal solutions. Background Art

[0002] As the heart of new energy vehicles, lithium-ion batteries are attracting widespread attention for their research, development, and production. To obtain active cathode materials with suitable morphology and proportions, a nickel-cobalt-manganese ternary precursor and lithium carbonate must be mixed and sintered under certain conditions. Therefore, ensuring a stable supply of these precursors and other materials is crucial for battery production. These precursor powders must be obtained from a high-purity nickel-cobalt-manganese sulfate solution. Therefore, the low-cost, large-scale production of these high-purity precursor solutions is crucial.

[0003] Crude nickel-cobalt-manganese sulfate solution is generally obtained by leaching waste battery powder, which is a relatively mature technology. During the leaching process, impurities such as iron, aluminum, copper, phosphorus, and titanium may be leached into the solution simultaneously. These impurities must be deeply removed to obtain a high-purity precursor solution. Traditional methods for removing impurities from nickel-cobalt-manganese sulfate solution include: hydrolysis precipitation to generate insoluble hydroxides of elements such as Fe and Al to remove Fe and Al impurities in the solution; iron powder and manganese powder replacement method to remove Cu impurities in the solution; calcium magnesium precipitation method or rare earth oxidant adsorption to remove F impurities in the solution. These methods still have the following problems: (1) It is easy to cause the loss of the main metal; (2) A certain amount of new impurity elements will be introduced during the impurity removal process; (3) The types of elements considered are relatively small, and the more complex solution environment in actual production is not fully considered. Summary of the Invention

[0004] In response to the above technical problems, the present application provides a method for purifying and removing impurities from a crude nickel-cobalt-manganese sulfate solution.

[0005] To achieve the above objectives, this application proposes the following technical solutions:

[0006] The present invention provides a method for purifying and removing impurities from a crude nickel, cobalt, and manganese sulfate solution, comprising:

[0007] (1) adding sodium thiosulfate to a crude nickel-cobalt-manganese sulfate solution to react, and subjecting the product to solid-liquid separation to obtain copper-removed slag and copper-removed liquid;

[0008] (2) adding phosphate to the copper-removed solution, adjusting the pH to 3.5-4.0, reacting, and separating the product into solid and liquid to obtain a titanium-iron-aluminum-removed solution and a titanium-iron-aluminum slag;

[0009] (3) Adding ferric sulfate to the liquid after titanium, iron and aluminum removal, adjusting the pH value to 3.5-4.0, reacting, and separating the product into solid and liquid to obtain the liquid after phosphorus and silicon removal and phosphorus and silicon slag;

[0010] (4) adding bismuth agent to the dephosphorus and silicon liquid to react, and separating the product into solid and liquid to obtain dechlorination slag and dechlorination liquid;

[0011] (5) adding a fluorine agent to the dechlorinated liquid to react, and separating the product into solid and liquid to obtain calcium and magnesium slag and dechlorinated liquid;

[0012] (6) Adding moraine mineral adsorbent to the decalcified and magnesium-removed liquid to react, and the product is separated into solid and liquid to obtain defluorinated slag and defluorinated liquid.

[0013] Furthermore, in step (1), the molar ratio of the sodium thiosulfate to the copper in the crude nickel-cobalt-manganese sulfate solution is 1.5-3.0:1.

[0014] Furthermore, in step (1), the pH value of the crude nickel-cobalt-manganese sulfate solution is 0.5-2.0;

[0015] Furthermore, in step (1), the reaction temperature is 50-80°C;

[0016] Furthermore, in step (1), the reaction time is 1 to 3 hours.

[0017] Furthermore, the crude nickel-cobalt-manganese sulfate solution is a valuable metal leaching solution obtained after the recovery of ternary lithium-ion batteries.

[0018] Furthermore, the crude nickel-cobalt-manganese sulfate solution includes main metals and impurity elements.

[0019] Furthermore, in the crude nickel-cobalt-manganese sulfate solution, the total concentration of the main metals is 50-150 g / L; and the concentration of each impurity element is 50-3000 mg / L.

[0020] Furthermore, the main metal includes Ni, Co and Mn, and optionally Li (i.e., the main metal includes Ni, Co and Mn, or the main metal includes Ni, Co, Mn and Li); the impurity elements include Fe, Al, Cu, F, P, Ca, Mg, Cl, Si and Ti.

[0021] Furthermore, in step (2), the amount of the phosphate added is determined based on the phosphate being 1.2 to 1.6 times the total molar amount of iron and aluminum in the reaction system.

[0022] Furthermore, in step (2), the reaction temperature is 40-70° C.; and the reaction time is 1-3 h.

[0023] Furthermore, in step (3), the molar ratio of the iron content of the ferric sulfate to the residual phosphate in the solution after the titanium, iron and aluminum are removed is 1:1.0-1.5.

[0024] Furthermore, in step (3), the reaction temperature is 40-70°C.

[0025] Furthermore, in step (3), the reaction time is 1 to 3 hours.

[0026] Furthermore, in step (4), the bismuth agent is Bi(OH)SO4 or Bi2(SO4)3; and the molar ratio of Bi in the bismuth agent to Cl in the phosphorus-silicon removal solution is 1.2-1.5.

[0027] Furthermore, in step (4), after adding the bismuth agent, the pH value of the solution is adjusted to 3.5-4.0.

[0028] Furthermore, in step (4), the reaction temperature is 30-50°C.

[0029] Furthermore, in step (4), the reaction time is 1 to 4 hours.

[0030] Furthermore, in step (5), the fluorine agent is one or more of sodium fluoride, manganese fluoride, and ammonium fluoride.

[0031] Furthermore, the ratio of the molar amount of fluorine in the fluorine agent to the total molar amount of calcium and magnesium in the dechlorinated liquid is 4.0-6.0.

[0032] Furthermore, in step (5), after adding the fluorine agent, the pH value of the solution is adjusted to 3.5-4.0.

[0033] Furthermore, in step (5), the reaction temperature is 50-80°C.

[0034] Furthermore, in step (5), the reaction time is 2 to 8 hours.

[0035] Furthermore, in step (6), the particle size D of the moraine mineral adsorbent is 50 5~25 μm.

[0036] Furthermore, in step (6), the amount of the moraine mineral adsorbent is not less than 15 g / L.

[0037] Furthermore, in step (6), after adding the moraine mineral adsorbent, the pH value of the solution is adjusted to 3.5-4.0.

[0038] Furthermore, in step (6), the reaction temperature is 40-70°C.

[0039] Furthermore, in step (6), the reaction time is 1 to 3 hours.

[0040] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects:

[0041] The treatment method of the present invention can efficiently remove elements such as iron, aluminum, copper, fluorine, phosphorus, titanium, calcium, magnesium, chlorine, and silicon from a crude nickel-cobalt-manganese sulfate solution, with low main metal loss. The prepared high-purity nickel-cobalt-manganese sulfate solution can directly meet the requirements of a precursor solution at the battery preparation level. The process is simple, the operation difficulty is low, and industrial-scale production can be easily achieved, thereby overcoming the shortcomings of the current method for preparing high-purity nickel-cobalt-manganese sulfate solution.

[0042] The treatment method of the present invention has a low main metal element loss rate, which can be controlled as low as 2-6%. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 The figure is a flow chart of the purification and impurity removal process of the battery metal sulfate solution of the present invention. DETAILED DESCRIPTION

[0045] There is Cu in the battery metal sulfate solution 2+ 、Fe 3+ 、Al 3+ 、F - PO4 3- 、Ti 4+ , Ca 2+ Mg 2+ 、Cl - 、H2SiO4 2- How to remove these impurity ions as much as possible while reducing the loss of main metals in the battery metal sulfate solution, such as Ni, Co, Mn, etc., has always been a difficult problem in the field of battery positive electrode material recycling.

[0046] After extensive research, the applicant has proposed a method that is economical, efficient, has a high recovery rate of main metals, and can completely remove impurities to obtain a high-purity nickel, cobalt, and manganese sulfate solution. The applicant uses a step-by-step, specific method to gradually remove each element completely. Specifically, sodium thiosulfate is first used to remove Cu 2+ Then, phosphate was added and pH was adjusted to remove Ti by ion content control. 4+ 、Fe 3+ 、Al 3+ PO43- Then, ferric sulfate reagent was used to remove phosphorus and silicon by precipitation and coagulation adsorption at a certain pH value, and bismuth reagent was used to remove Cl under certain pH conditions. - , followed by the removal of calcium and magnesium using a fluorine agent, and finally the removal of fluorine using a moraine mineral adsorbent. The present invention provides a method for removing impurity elements contained in the solution by step-by-step precipitation and adsorption: sodium thiosulfate for copper removal - phosphate precipitation for titanium, iron, and aluminum removal - iron phosphate precipitation for phosphorus and silicon removal - bismuth oxychloride for chlorine removal - fluoride precipitation for calcium and magnesium removal - and mineral adsorbent for fluorine removal. This process can achieve efficient and deep removal of impurity ions with minimal loss of the main metal, and can produce a high-purity metal sulfate solution for subsequent applications.

[0047] Specifically, the method for purifying and removing impurities from a crude nickel, cobalt, and manganese sulfate solution comprises:

[0048] (1) adding sodium thiosulfate to a crude nickel-cobalt-manganese sulfate solution to react, and subjecting the product to solid-liquid separation to obtain copper-removed slag and copper-removed liquid;

[0049] (2) adding phosphate to the copper-removed solution, adjusting the pH to 3.5-4.0, reacting, and separating the product into solid and liquid to obtain a titanium-iron-aluminum-removed solution and a titanium-iron-aluminum slag;

[0050] (3) Adding ferric sulfate to the liquid after titanium, iron and aluminum removal, adjusting the pH value to 3.5-4.0, reacting, and separating the product into solid and liquid to obtain the liquid after phosphorus and silicon removal and phosphorus and silicon slag;

[0051] (4) adding bismuth agent to the dephosphorus and silicon liquid to react, so that phosphorus and silicon are removed in the form of precipitation and coagulation adsorption, and the product is separated into solid and liquid to obtain dechlorination slag and dechlorination liquid;

[0052] (5) Adding a fluorine agent to the dechlorinated liquid to react and promote the conversion of calcium and magnesium into fluoride precipitation. The product is separated into solid and liquid to obtain calcium and magnesium slag and dechlorinated liquid;

[0053] (6) Adding moraine mineral adsorbent to the decalcified and magnesium-removed liquid to react, and the product is separated into solid and liquid to obtain defluorinated slag and defluorinated liquid.

[0054] The present invention starts from the solution composition of actual battery metal leachate and designs a sulfuric acid-based battery metal solution with a large number of impurity elements. It can basically cover all types of battery metal leachate, has low processing cost and low operation difficulty, and can deeply remove various impurities such as fluorine, chlorine, aluminum, and phosphorus while ensuring a low main metal loss rate. It has good industrial application prospects.

[0055] In the copper removal step (1), thiosulfate S2O3 2- In the 2+The CuS2O3 formed after the combination can decompose at high temperature to produce extremely insoluble CuS. In some preferred embodiments, the ratio of the amount of sodium thiosulfate reagent used in the reaction to the molar amount of copper in the crude nickel-cobalt-manganese sulfate solution (battery metal sulfate stock solution) is n(S2O3 2- ):n(Cu 2+ ) is 1.5~3.0:1, such as 1.5:1, 1.8:1, 2.0:1, 2.2:1, 2.5:1, 2.8:1, 3:1, etc. In some embodiments, the pH value of the battery metal sulfate stock solution is 0.5~2.0, such as 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2, etc. The main metal elements of nickel, cobalt and manganese are K due to their sulfide sp It is relatively high and basically does not precipitate at a pH of 0.5 to 2.0, thereby ensuring that the main metal will not be lost during the impurity removal process. In some preferred embodiments, the reaction temperature is 50 to 80°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, etc. In some preferred embodiments, the reaction time is 1 to 3 h, for example, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, etc. Step (1) has a good copper removal effect and does not cause the loss of the main metal. In some preferred embodiments, in step (1), the copper removal slag is nano copper sulfide; in step (1), the copper removal rate in the copper removal solution exceeds 99.9%.

[0056] In the titanium, iron and aluminum removal step (2), the phosphate content and the pH value of the solution are adjusted to cause the titanium, iron and aluminum to precipitate in the form of precipitation. The resulting phosphate precipitate has better filtration performance than the hydroxide precipitate of iron and aluminum. By controlling the pH value, the efficiency of the impurity removal operation can be effectively improved and the hydrolysis precipitation loss of the main metal can be reduced. In some preferred embodiments, during the reaction, PO4 3- The content is n(PO4 3- )=(1.2~1.6)×[n(Fe 3+ )+n(Al 3+ )], for example, 1.2 times, 1.3 times, 1.4 times, 1.5 times, 1.6 times. In some preferred embodiments, in step (2), the reaction temperature should be 40~70℃, for example, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, etc.; in some preferred embodiments, in step (2), the reaction time is 1~3 h, for example, 1h, 1.5 h, 2 h, 2.5 h, 3 h, etc. The operating pH in this step is low, so the main metal will not precipitate in the form of hydroxide and phosphate during this process, and the loss rate is low. In some preferred embodiments, in step (2), the main elements in the titanium ferro slag are Ti, Fe, Al and P; the removal rate of Ti, Fe and Al in the copper removal solution is higher than 99.9%.

[0057] In the phosphorus and silicon removal step (3), by adding ferric sulfate and adjusting the pH value of the solution, phosphorus and silicon are removed in the form of ferric phosphate and coagulation adsorption respectively. This method not only has a good effect on the removal of phosphorus and silicon, but also reduces the loss of main metals. In some preferred embodiments, the amount of ferric sulfate reagent used is the same as the residual PO4 in the solution after titanium, iron and aluminum removal. 3- The molar ratio n(PO4 3- ):n(Fe 3+ ) is 1.0~1.5, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, etc. In some preferred embodiments, in step (3), the reaction temperature is 40~70°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, etc. In some embodiments, the reaction time is 1~3 h, for example, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, etc. This step has a good removal effect on phosphorus silicon. In step (3), the main elements of the phosphorus silicon slag are Fe, P, Si, etc. In some preferred embodiments, in step (3), the phosphorus removal rate of the liquid after dephosphorus silicon is higher than 99.9%; the silicon removal rate of the liquid after dephosphorus silicon is higher than 90.0%.

[0058] In the chlorine removal step (4), the added Bi agent such as BiOHSO4 or Bi2(SO4)3 reacts with the Cl in the solution. - Ion exchange occurs to generate insoluble BiOCl. Since the Bi agent itself is also insoluble in water, no Bi impurity element is introduced in the process. This method not only has excellent chlorine removal effect, but also the reactant Bi agent can be recycled. In some preferred embodiments, the molar ratio of Bi in the bismuth agent to Cl in the solution after dephosphorization and siliconization during the reaction is n(Bi 3+ ):n(Cl - ) is not less than 1.2, preferably 1.2-1.5, such as 1.2, 1.3, 1.4, 1.5, etc. In some preferred embodiments, in step (4), the reaction temperature is 30-50°C, such as 30°C, 35°C, 40°C, 45°C, 50°C, etc., and the reaction time is 1-4 h, such as 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, etc. In some preferred embodiments, in step (4), after adding the bismuth agent, the pH value of the solution is adjusted to 3.5-4.0, such as 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, etc. In some preferred embodiments, in step (4), the main components of the dechlorination slag are BiOCl and a small amount of unreacted Bi agent; the removal rate of Cl in the dechlorinated liquid exceeds 95.0%.

[0059] In the calcium and magnesium removal step (5), Ca and Mg ions react with F -Combined to form CaF2 and MgF2 insoluble precipitates, which are then removed by solid-liquid separation. The precipitate produced in this process is in colloidal form, so the morphology of the precipitate can be improved by appropriately increasing the temperature and extending the time. In some preferred embodiments, the fluorine agent in the reaction process in step (5) is one or more reagents such as NaF, MnF2, NH4F, etc. In some preferred embodiments, the ratio of the amount of fluorine agent used in step (5) to the molar amount of calcium and magnesium in the solution is n(F - ):n[(Ca 2+ )+n(Mg 2+ )] is 4.0-6.0, for example, 4.0, 4.2, 4.5, 4.8, 5.0, 5.2, 5.5, 5.8, 6.0, etc. In some preferred embodiments, in step (5), the pH of the reaction is 3.5-4.0, for example, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, etc. In some preferred embodiments, in step (5), the reaction temperature is 50-80°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, etc. In some preferred embodiments, in step (5), the reaction time is 2-8 h, for example, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, etc. This step is easy to operate and has good industrial application potential. In step (5), the main elements in the calcium-magnesium slag are Ca, Mg, and F. In some preferred embodiments, in step (5), the calcium removal rate in the calcium-magnesium slag is 97% to 98%, and the magnesium removal rate is 90% to 91%.

[0060] In the defluorination step, the metal oxide active sites on the mineral surface react with F - Electrostatic adsorption is performed, so changes in parameters such as temperature and pH have a greater impact on the adsorption capacity. In some preferred embodiments, the particle size D of the moraine mineral adsorbent used in the reaction process is 50 is 5~25 μm. In some preferred embodiments, the amount of adsorbent used is not less than 15 g / L. In some preferred embodiments, the reaction temperature is 40~70°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, etc. In some preferred embodiments, the reaction time is 1~3 h, for example, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, etc. The use of mineral adsorbents in this step is extremely low in cost and has excellent effects, and has strong development potential. In some preferred embodiments, in step (6), the main component of the defluorination slag is moraine mineral that adsorbs F elements; in step (6), the fluorine removal rate in the defluorination liquid is higher than 99.9%.

[0061] In some preferred embodiments, the crude nickel-cobalt-manganese sulfate solution is a valuable metal leachate obtained from the recovery of ternary lithium-ion batteries; the crude nickel-cobalt-manganese sulfate solution includes primary metals and impurity elements. In some preferred embodiments, the total concentration of the primary metals in the crude nickel-cobalt-manganese sulfate solution is 50-150 g / L; the concentration of each impurity element is 50-3000 mg / L. In some preferred embodiments, the primary metals include Ni, Co, and Mn, and may also contain Li; the impurity elements include Fe, Al, Cu, F, P, Ca, Mg, Cl, Si, and Ti.

[0062] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with the accompanying drawings and preferred embodiments. However, the scope of protection of the present invention is not limited to the following specific embodiments.

[0063] Example 1

[0064] The raw solution to be purified is a crude sulfate solution after battery leaching, in which the total content of the main metals nickel, cobalt and manganese is 105 g / L, the impurity elements iron content is 750 ppm, aluminum content is 1500 ppm, copper content is 1200 ppm, fluorine content is 1400 ppm, phosphorus content is 1200 ppm, titanium content is 400 ppm, calcium content is 400 ppm, magnesium content is 300 ppm, chlorine content is 750 ppm, and silicon content is 150 ppm.

[0065] (1) The pH value of the original solution is about 1.0. Sodium thiosulfate reagent is added to the original solution. The molar ratio of sodium thiosulfate to copper in the battery metal sulfate solution is 1.5:1. The solution is placed in a 50°C water bath and stirred for 1 h. Then, the copper-removed slag nano-CuS and the copper-removed solution are obtained by filtration.

[0066] (2) Sodium phosphate is added to the copper removal solution in an amount of 1.2 times the total molar amount of iron ions and aluminum ions in the copper removal solution, and calcium hydroxide suspension and dilute sulfuric acid are added to adjust the pH value of the solution to 3.5. The solution is stirred and reacted at 50°C for 2 hours, and filtered to obtain titanium, iron, and aluminum removal solution and titanium, iron, and aluminum removal slag, wherein the main elements of the titanium, iron, and aluminum removal slag are Ti, Fe, Al, P, etc.;

[0067] (3) Add ferric sulfate reagent to the solution after titanium, iron and aluminum removal and adjust the pH value of the solution. The amount of ferric sulfate reagent added is in accordance with the ratio of the molar amount of residual phosphate in the solution after titanium, iron and aluminum removal, n(PO4 3- ):n(Fe 3+ ) was determined to be 1.0, the pH value was adjusted to 3.5, the reaction was carried out at 50℃ for 2 h, and the mixture was filtered to obtain the dephosphorus-silicon liquid and dephosphorus-silicon slag. The main chemical components of the dephosphorus-silicon slag were Fe, P, Si, etc.

[0068] (4) Add BiOHSO4 to the solution after removing phosphorus and silicon and adjust the pH value of the solution. The amount of BiOHSO4 added is based on the ratio of the molar amount of chloride ions in the solution n(Bi 3+ ):n(Cl - ) was 1.2, the pH value was adjusted to 3.5, the reaction was carried out at 50°C for 2h, and the mixture was filtered to obtain dechlorination residue and dechlorination liquid. The main components of the dechlorination residue were BiOCl and a small amount of unreacted Bi agent.

[0069] (5) Sodium fluoride is added to the dechlorinated liquid. The fluoride ion in the fluorine agent is 4.0 times the total molar amount of calcium and magnesium in the dechlorinated liquid. The pH of the solution is 3.5. The reaction is carried out at 50°C for 2 hours. The solution is filtered to obtain calcium and magnesium slag and dechlorinated liquid. The main elements in the calcium and magnesium slag are Ca, Mg, F, etc.

[0070] (6) Add a moraine mineral adsorbent with a particle size D50 of about 15 μm to the decalcified and magnesium-removed liquid. The amount of adsorbent added is 15 g / L, the pH of the solution is 3.5, and the reaction is carried out at 50°C for 2 h. After filtration, the defluorinated slag and the de-impurity liquid are obtained.

[0071] Example 2

[0072] The stock solution to be purified is the same as that in Example 1.

[0073] (1) The pH value of the original solution is about 1.0. Sodium thiosulfate reagent is added to the original solution. The molar ratio of sodium thiosulfate to copper in the battery metal sulfate solution is 1.5:1. The solution is placed in a 50°C water bath and stirred for 1 h. Then, the copper-removed slag nano-CuS and the copper-removed solution are obtained by filtration.

[0074] (2) Sodium phosphate was added to the copper removal solution in an amount of 1.2 times the total molar amount of iron ions and aluminum ions in the copper removal solution. Calcium hydroxide suspension and dilute sulfuric acid were added to adjust the pH value of the solution to 4.0. The solution was stirred at 50°C for 2 h and filtered to obtain titanium, iron, and aluminum removal solution and titanium, iron, and aluminum removal slag.

[0075] (3) Add ferric sulfate reagent to the solution after titanium, iron and aluminum removal and adjust the pH value of the solution. The amount of ferric sulfate reagent added is based on the ratio of the molar amount of residual phosphate in the solution after titanium, iron and aluminum removal, n(PO4 3- ):n(Fe 3+ ) was determined to be 1.0, the pH value was adjusted to 4, the reaction was carried out at 50 ° C for 2 h, and the solution after dephosphorization and dephosphorization were obtained.

[0076] (4) After removing phosphorus and silicon, add BiOHSO4 to the solution and adjust the pH value of the solution to 4.0. The amount of BiOHSO4 added is based on the ratio of the molar amount of chloride ions in the solution n(Bi 3+ ):n(Cl -) was 1.2, and the mixture was reacted at 30 °C for 2 h. The mixture was filtered to obtain dechlorination residue and dechlorination liquid. The main components of the dechlorination residue were BiOCl and a small amount of unreacted Bi agent.

[0077] (5) Sodium fluoride is added to the dechlorinated liquid. The fluoride ion in the fluorine agent is 4.0 times the total molar amount of calcium and magnesium in the dechlorinated liquid. The pH of the solution is 4.0. The reaction is carried out at 50°C for 2 hours. The solution is filtered to obtain calcium and magnesium slag and dechlorinated liquid. The main elements in the calcium and magnesium slag are Ca, Mg, F, etc.

[0078] (6) Add a moraine mineral adsorbent with a particle size D50 of about 15 μm to the calcium and magnesium removed solution. The amount of adsorbent added is 15 g / L, the solution pH is 4.0, and the mixture is reacted at 50°C for 2 h. After filtration, the fluorine removal residue and the impurity removal solution are obtained.

[0079] Example 3

[0080] The stock solution to be purified is the same as that in Example 1.

[0081] (1) The pH value of the original solution is about 1.0. Sodium thiosulfate reagent is added to the original solution. The molar ratio of sodium thiosulfate to copper in the battery metal sulfate original solution is 1.5:1. The solution is placed in a 70°C water bath and stirred for 3 hours. Then, the copper-removed slag nano-CuS and the copper-removed liquid are obtained by filtration.

[0082] (2) Sodium phosphate is added to the copper removal solution. The amount of phosphate added is in accordance with the molar ratio of the total amount of iron ions and aluminum ions in the copper removal solution n(PO4 3- )=1.6[n(Fe 3+ )+n(Al 3+ )] and add calcium hydroxide suspension and dilute sulfuric acid to adjust the pH value of the solution to 3.5, keep stirring at 70 ° C for 3 hours, filter, and obtain the titanium, iron and aluminum removal liquid and titanium, iron and aluminum removal slag, in which the main elements are Ti, Fe, Al, P, etc.;

[0083] (3) Add ferric sulfate reagent to the solution after titanium, iron and aluminum removal and adjust the pH value of the solution. The amount of ferric sulfate reagent added is based on the ratio of the molar amount of residual phosphate in the solution after titanium, iron and aluminum removal to n(PO4 3- ):n(Fe 3+ ) was determined to be 1.0, the pH value was adjusted to 3.5, the reaction was carried out at 70℃ for 3 h, and the mixture was filtered to obtain the dephosphorus-silicon liquid and dephosphorus-silicon slag. The main chemical components of the dephosphorus-silicon slag were Fe, P, Si, etc.

[0084] (4) After removing phosphorus and silicon, add BiOHSO4 to the solution and adjust the pH value of the solution to 4.0. The amount of BiOHSO4 added is based on the ratio of the molar amount of chloride ions in the solution n(Bi 3+ ):n(Cl -) is 1.2, and the reaction is carried out at 50 °C for 3 h. The dechlorination residue and dechlorination liquid are obtained by filtration. The main components of the dechlorination residue are BiOCl and a small amount of unreacted Bi agent.

[0085] (5) Sodium fluoride is added to the dechlorinated liquid. The fluoride ion in the fluorine agent is 4.0 times the total molar amount of calcium and magnesium in the dechlorinated liquid. The pH of the solution is 3.5. The reaction is carried out at 70°C for 3 hours. The solution is filtered to obtain calcium and magnesium slag and dechlorinated liquid. The main elements in the calcium and magnesium slag are Ca, Mg, F, etc.

[0086] (6) Add a moraine mineral adsorbent with a particle size D50 of about 15 μm to the decalcified and magnesium-removed liquid. The amount of adsorbent added is 15 g / L, the pH of the solution is 3.5, and the reaction is carried out at 70°C for 3 h. After filtration, the defluorinated slag and the de-impurity liquid are obtained.

[0087] Example 4

[0088] The stock solution to be purified is the same as that in Example 1.

[0089] (1) The pH value of the original solution is about 1.0. Sodium thiosulfate reagent is added to the original solution. The molar ratio of sodium thiosulfate to copper in the battery metal sulfate original solution is 3 times. The solution is placed in a 50°C water bath and stirred for 1 hour. Then, the copper-removed slag nano-CuS and the copper-removed liquid are obtained by filtration.

[0090] (2) Sodium phosphate was added to the copper removal solution in an amount of 1.2 times the total molar amount of iron ions and aluminum ions in the copper removal solution, and calcium hydroxide suspension and dilute sulfuric acid were added to adjust the pH value of the solution to 3.5. The solution was stirred at 50°C for 2 h and filtered to obtain titanium, iron, and aluminum removal solution and titanium, iron, and aluminum removal slag, wherein the main elements of the titanium, iron, and aluminum removal slag were Ti, Fe, Al, P, etc.;

[0091] (3) Add ferric sulfate reagent to the solution after titanium, iron and aluminum removal and adjust the pH value of the solution. The amount of ferric sulfate reagent added is in accordance with the ratio of the molar amount of residual phosphate in the solution after titanium, iron and aluminum removal, n(PO4 3- ):n(Fe 3+ ) was determined to be 1.0, the pH value was adjusted to 3.5, the reaction was carried out at 50℃ for 2 h, and the mixture was filtered to obtain the dephosphorus-silicon liquid and dephosphorus-silicon slag. The main chemical components of the dephosphorus-silicon slag were Fe, P, Si, etc.

[0092] (4) Add BiOHSO4 to the solution after removing phosphorus and silicon and adjust the pH value of the solution. The amount of BiOHSO4 added is based on the ratio of the molar amount of chloride ions in the solution n(Bi 3+ ):n(Cl - ) was 1.2, the pH value was adjusted to 3.5, the reaction was carried out at 50 °C for 2 h, and the dechlorination residue and dechlorination liquid were obtained by filtration. The main components of the dechlorination residue were BiOCl and a small amount of unreacted Bi agent.

[0093] (5) Sodium fluoride is added to the dechlorinated liquid. The fluoride ion in the fluorine agent is 4.0 times the total molar amount of calcium and magnesium in the dechlorinated liquid. The pH of the solution is 3.5. The reaction is carried out at 50°C for 2 hours. The solution is filtered to obtain calcium and magnesium slag and dechlorinated liquid. The main elements in the calcium and magnesium slag are Ca, Mg, F, etc.

[0094] (6) Add a moraine mineral adsorbent with a particle size D50 of about 15 μm to the decalcified and magnesium-removed liquid. The amount of adsorbent added is 15 g / L, the pH of the solution is 3.5, and the reaction is carried out at 50°C for 2 h. After filtration, the defluorinated slag and the de-impurity liquid are obtained.

[0095] Example 5

[0096] The difference between Example 1 and Example 1 is only that step (5) is different. Sodium fluoride is added to the dechlorinated liquid. The fluoride ion in the fluorine agent is 5.0 times the total molar amount of calcium and magnesium in the dechlorinated liquid. The pH of the solution is 3.5. The reaction is carried out at 80°C for 2 hours. The solution is filtered to obtain calcium and magnesium slag and dechlorinated liquid. The main elements in the calcium and magnesium slag are Ca, Mg, F, etc.

[0097] Example 6

[0098] The difference between the embodiment and embodiment 1 is that step (3) is different. Add ferric sulfate reagent to the solution after titanium, iron and aluminum removal and adjust the pH value of the solution. The amount of ferric sulfate reagent added is in accordance with the ratio of the molar amount of the residual phosphate in the solution after titanium, iron and aluminum removal, n(PO4 3- ):n(Fe 3+ ) was determined to be 1.5, the pH value was adjusted to 4.0, the reaction was carried out at 50℃ for 2 h, and the mixture was filtered to obtain the dephosphorus-silicon liquid and dephosphorus-silicon slag. The main chemical components of the dephosphorus-silicon slag were Fe, P, Si, etc.

[0099] Example 7

[0100] The difference between this embodiment and embodiment 1 is only in step (1). Step (1): The pH value of the original solution is about 1.0. Sodium thiosulfate reagent is added to the original solution. The molar ratio of sodium thiosulfate to copper in the battery metal sulfate original solution is 1. The solution is placed in a 30°C water bath and stirred for 1 hour. The solution is then filtered to obtain copper-removed slag nano-CuS and copper-removed liquid.

[0101] Comparative Example 1

[0102] The comparative example is basically the same as Example 1, with the only difference being that in step (6), the "treasure rock mineral adsorbent" is replaced with "rare earth oxide (La2O3)", and the amount of rare earth oxide added is 0.3 g / L (it has been verified that this amount of rare earth oxide has a better fluorine removal effect and is typical of the fluorine removal effect of this substance).

[0103] Comparative Example 2

[0104] The difference between this comparative example and Example 1 is only that step (2) is different. Step (2): Sodium phosphate is added to the copper-removed liquid, and the amount of sodium phosphate added is 1.6 times the total molar amount of iron ions and aluminum ions in the copper-removed liquid. Calcium hydroxide suspension and dilute sulfuric acid are added to adjust the pH value of the solution to 4.5. The solution is stirred and reacted at 50°C for 2 hours, and filtered to obtain a titanium, iron, and aluminum-removed liquid and a titanium, iron, and aluminum-removed slag, wherein the main elements of the titanium, iron, and aluminum-removed slag are Ti, Fe, Al, P, etc.

[0105] Comparative Example 3

[0106] The difference between this comparative example and Example 1 is only in step (3). Step (3): Add ferric sulfate reagent to the solution after titanium, iron and aluminum removal and adjust the pH value of the solution. The amount of ferric sulfate reagent added is in the ratio of the molar amount of the residual phosphate in the solution after titanium, iron and aluminum removal, n(PO4 3- ):n(Fe 3+ ) was determined to be 0.75, the pH value was adjusted to 3.0, the reaction was carried out at 50℃ for 2 h, and the solution was filtered to obtain the dephosphorus-silicon liquid and dephosphorus-silicon slag. The main chemical components of the dephosphorus-silicon slag were Fe, P, Si, etc.

[0107] Comparative Example 4

[0108] The difference between this comparative example and Example 1 is only in step (3). Step (3): Add ferric sulfate reagent to the solution after titanium, iron and aluminum removal and adjust the pH value of the solution. The amount of ferric sulfate reagent added is in the ratio of the molar amount of the residual phosphate in the solution after titanium, iron and aluminum removal, n(PO4 3- ):n(Fe 3+ ) was determined to be 1.6, the pH value was adjusted to 4.5, the reaction was carried out at 50℃ for 2 h, and the mixture was filtered to obtain the dephosphorus-silicon liquid and dephosphorus-silicon slag. The main chemical components of the dephosphorus-silicon slag were Fe, P, Si, etc.

[0109] Comparative Example 5

[0110] The difference between this comparative example and Example 1 is only in step (4). A moraine mineral adsorbent having a particle size D50 of approximately 15 μm is added to the decalcified and magnesium-removed solution. The amount of adsorbent added is 15 g / L. The solution pH is 5. The reaction is carried out at 50°C for 2 h. After filtration, defluorinated slag and impurity-removed solution are obtained.

[0111] Table 1 Test results of the impurity-removed liquid obtained in each embodiment and comparative example (element content unit: ppm)

[0112]

[0113] As can be seen from Table 1, the main metal loss rate in Examples 1 to 7 is below 6%, and the difference is not large, and the impurity content in the purified liquid is low; compared with the traditional fluorine removal method of rare earth oxide (La2O3) commonly used on the market in Comparative Example 1, the fluorine removal effect of moraine mineral adsorbent is more excellent, and the effect on the main metal is not significant.

[0114] It can also be seen from Table 1 that in step (2), when the phosphate ions are sufficient, when the pH value is high, the main metal loss rate is too large; in step (3), when the pH is too low, the removal effect of phosphorus silicon is poor, and when the pH is too high, the main metal loss rate increases significantly.

[0115] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for purifying and removing impurities from a crude nickel-cobalt-manganese sulfate solution, characterized in that: include: (1) adding sodium thiosulfate to a crude nickel-cobalt-manganese sulfate solution, reacting, and subjecting the product to solid-liquid separation to obtain copper-removed slag and copper-removed liquid; the pH value of the crude nickel-cobalt-manganese sulfate solution is 0.5-2.0; (2) adding phosphate to the copper-removed solution, adjusting the pH to 3.5-4.0, reacting, and separating the product into solid and liquid to obtain a titanium-iron-aluminum-removed solution and a titanium-iron-aluminum slag; (3) Adding ferric sulfate to the liquid after titanium, iron and aluminum removal, adjusting the pH value to 3.5-4.0, reacting, and separating the product into solid and liquid to obtain the liquid after phosphorus and silicon removal and phosphorus and silicon slag; (4) adding a bismuth agent to the dephosphorus and silicon liquid, reacting, and separating the product into a solid-liquid phase to obtain a dechlorination slag and a dechlorination liquid; the bismuth agent is Bi(OH)SO4 or Bi2(SO4)3; (5) adding a fluorine agent to the dechlorinated liquid, reacting, and separating the product into solid and liquid to obtain calcium-magnesium slag and dechlorinated liquid; the fluorine agent is one or more of sodium fluoride, manganese fluoride, and ammonium fluoride; (6) Adding moraine mineral adsorbent to the decalcified and magnesium-removed liquid to react, and the product is separated into solid and liquid to obtain defluorinated slag and defluorinated liquid.

2. The method for purifying and removing impurities from a crude nickel-cobalt-manganese sulfate solution according to claim 1, wherein: In step (1), the molar ratio of the sodium thiosulfate to the copper in the crude nickel-cobalt-manganese sulfate solution is 1.5-3.0:1; In step (1), the reaction temperature is 50-80°C; In step (1), the reaction time is 1 to 3 hours.

3. The method for purifying and removing impurities from a crude nickel-cobalt-manganese sulfate solution according to claim 1, wherein: The crude nickel-cobalt-manganese sulfate solution is a valuable metal leachate obtained after the recovery of ternary lithium-ion batteries; The crude nickel-cobalt-manganese sulfate solution includes main metals and impurity elements; In the crude nickel-cobalt-manganese sulfate solution, the total concentration of the main metal is 50-150 g / L; the concentration of each impurity element is 50-3000 mg / L; The main metals include Ni, Co and Mn, and optionally Li; the impurity elements include Fe, Al, Cu, F, P, Ca, Mg, Cl, Si and Ti.

4. The method for purifying and removing impurities from a crude nickel-cobalt-manganese sulfate solution according to claim 1, wherein: In step (2), the amount of the phosphate added is determined based on the phosphate being 1.2 to 1.6 times the total molar amount of iron and aluminum in the reaction system; In step (2), the reaction temperature is 40-70° C.; the reaction time is 1-3 h.

5. The method for purifying and removing impurities from a crude nickel-cobalt-manganese sulfate solution according to claim 1, wherein: In step (3), the molar ratio of the iron in the ferric sulfate to the residual phosphate in the solution after the titanium, iron and aluminum are removed is 1:1.0-1.5; In step (3), the reaction temperature is 40-70°C; In step (3), the reaction time is 1 to 3 hours.

6. The method for purifying and removing impurities from a crude nickel-cobalt-manganese sulfate solution according to claim 1, wherein: In step (4), the molar ratio of Bi in the bismuth agent to Cl in the phosphorus-silicon removal solution is 1.2 to 1.

5.

7. The method for purifying and removing impurities from a crude nickel-cobalt-manganese sulfate solution according to claim 1, wherein: In step (4), the reaction temperature is 30-50°C; In step (4), after adding the bismuth agent, the pH value of the solution is adjusted to 3.5-4.0; In step (4), the reaction time is 1 to 4 hours.

8. The method for purifying and removing impurities from a crude nickel-cobalt-manganese sulfate solution according to claim 1, wherein: In step (5), the ratio of the molar amount of fluorine in the fluorine agent to the total molar amount of calcium and magnesium in the dechlorinated liquid is 4.0-6.

0.

9. The method for purifying and removing impurities from a crude nickel-cobalt-manganese sulfate solution according to claim 1, wherein: In step (5), after adding the fluorine agent, the pH value of the solution is adjusted to 3.5-4.0; In step (5), the reaction temperature is 50-80°C; In step (5), the reaction time is 2 to 8 h.

10. The method for purifying and removing impurities from a crude nickel-cobalt-manganese sulfate solution according to claim 1, wherein: In step (6), the particle size D of the moraine mineral adsorbent is 50 5~25 μm; In step (6), the amount of the moraine mineral adsorbent is not less than 15 g / L; In step (6), after adding the moraine mineral adsorbent, the pH value of the solution is adjusted to 3.5-4.0; In step (6), the reaction temperature is 40-70°C; In step (6), the reaction time is 1 to 3 hours.

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