Method for recovering and separating nickel, cobalt and manganese from lithium extraction slag of waste ternary lithium ion battery material

Abstract

The invention discloses a method for recovering and separating nickel, cobalt and manganese from waste ternary lithium ion battery material lithium extraction slag, which comprises the following steps: pulping waste ternary battery material lithium extraction slag, leaching, introducing compressed air as an oxidant, and carrying out solid-liquid separation after leaching to obtain a leachate and leaching slag; sequentially performing copper removal, iron removal, aluminum removal and fluorine removal on the leachate to finally obtain fluorine-removed liquid; carrying out refined filtration on the fluorine-removed liquid to obtain a refined-filtered liquid; adjusting the pH value of the finely filtered liquid, and extracting impurities by using nickel soap P204 to obtain a rich organic phase and raffinate 1; extracting manganese from the raffinate 1 by using nickel soap P204 to obtain a manganese-rich organic phase and raffinate 2; extracting cobalt from the raffinate 2 by using nickel soap P507 to obtain a cobalt-rich organic phase and raffinate 3; and carrying out evaporative crystallization on the raffinate 3 to obtain nickel sulfate. The whole process has the advantages of short flow, high metal recovery rate, high product quality and low sodium-containing wastewater treatment capacity, and nickel, cobalt, manganese and lithium elements in the waste ternary lithium ion battery material are efficiently recycled by combining a front-end lithium extraction and recovery process, so that resource circulation is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of battery recycling, and in particular relates to a method for recovering and separating nickel, cobalt and manganese from lithium extraction slag of waste ternary lithium-ion battery materials. Background Art

[0002] With the development of science and technology, the fields of electric vehicles and energy storage are constantly expanding, and the production and sales of lithium-ion batteries have also maintained a rapid growth, resulting in a large number of waste lithium-ion batteries accumulating year by year. If they are discarded at will, on the one hand, it will cause a serious threat to the environment and ecology, and on the other hand, it will cause the irreversible loss of the metals they contain. Therefore, recycling waste lithium-ion batteries and reusing the valuable metals in them will be an effective way for the sustainable development of the lithium-ion battery industry.

[0003] According to the different positive electrode materials, lithium-ion batteries can be mainly divided into lithium iron phosphate batteries and ternary lithium batteries. Among them, ternary lithium batteries contain valuable metal elements such as nickel, cobalt, manganese, and lithium. Compared with traditional non-ferrous metal smelting, the recovery of these valuable metal elements can greatly reduce energy consumption and production costs. At present, the recycling process of waste ternary lithium batteries is mainly divided into pyrometallurgical process and hydrometallurgical process. The pyrometallurgical recycling process usually requires a high temperature of more than 1000°C. The high energy consumption and waste gas generated in the recycling process increase the subsequent processing costs. More importantly, lithium eventually enters the slag, greatly reducing the overall recycling benefits. Wet recycling is to use acid or alkali to leach the metal elements in the battery materials obtained by disassembling the battery, and then separate the various elements by precipitation and extraction to obtain a higher purity recovery product.

[0004] The conventional wet recovery process is to leach all the metals in the waste ternary battery material powder to obtain a mixed metal salt solution rich in nickel, cobalt, manganese, and lithium, and then remove the copper, aluminum, iron and other ions in the solution, and then use the extraction method to obtain manganese salt solution, cobalt salt solution and nickel salt solution in turn. Lithium is mainly retained in the raffinate, which is prepared into lithium salt for recovery. Due to the long process flow, lithium is recovered at the end of the recovery process, resulting in a low lithium recovery rate. Therefore, in recent years, a selective and preferential lithium extraction recovery process has been developed. Generally, hydrogen, carbon and other reducing agents are used to reduce the ternary material, and the following reactions mainly occur: 2LiNi x Co y Mn z O2+H2 / C→Li2O+2xNi+2Co y Mn z O+H2O / CO, lithium in the reduction product can be leached out by simple water leaching, and efficient lithium recovery is completed first. Then the lithium extraction slag is leached, separated and recovered nickel, cobalt and manganese metal elements.

[0005] The Chinese invention patent with the publication number CN118127329A discloses a method for recovering nickel, cobalt and manganese from waste ternary battery powder. The nickel, cobalt and manganese slag after lithium extraction is leached with sulfuric acid solution. The main metal elements in the obtained acid leaching solution are Ni, Co, Mn, Ca, Zn, Cu, Al and Mg. The neutralizing agent limestone or zirconium hydroxide is added to the acid leaching solution. After impurities are removed, except for Ca and Mg, other impurity elements Zn, Cu and Al are deeply removed. P204 extraction-sulfuric acid stripping is used to obtain a manganese sulfate solution containing calcium and zinc, and then P507 extraction-sulfuric acid stripping is used to obtain a refined cobalt sulfate solution. The raffinate is a refined nickel sulfate solution. The removal of impurity magnesium must also be considered during the cobalt extraction process. This patent will introduce more impurity calcium or new impurity zirconium during the neutralization and impurity removal steps, and the calcium and magnesium ions are not removed, which is not conducive to the subsequent extraction process and affects the quality of the obtained product; at the same time, the fluorine content in the liquid after impurity removal in the embodiment is 15-36 mg / L, and there is no subsequent fluorine treatment in the patent, so these fluorine elements will remain in the refined nickel sulfate. Summary of the invention

[0006] The purpose of the present invention is to provide a method for recovering and separating nickel, cobalt and manganese from lithium slag extracted from waste ternary lithium-ion battery materials in view of the deficiencies of the prior art. The method uses lithium slag extracted from waste ternary lithium-ion battery materials as raw materials. The lithium slag itself does not contain calcium and magnesium elements. The calcium and magnesium impurities in the acid leaching solution mainly come from process water. Therefore, all water is preferentially subjected to calcium and magnesium removal to eliminate the influence of calcium and magnesium on the extraction process and product purity from the source. Sulfuric acid leaching is used to obtain a metal salt solution. Impurities in the leachate are removed by impurity removal procedures such as iron powder removal of copper, manganese carbonate removal of iron and aluminum, and defluorination agent removal of fluorine. P204 extractant after nickel soap is used to extract impurities, P204 extractant after nickel soap is used to extract and recover manganese, and P507 extractant after nickel soap is used to extract and recover cobalt, and nickel is recovered in the raffinate. The entire process has the advantages of high metal recovery rate, high product quality, and low sodium-containing wastewater treatment volume. Combined with the front-end preferential lithium extraction and recovery process, nickel, cobalt, manganese and lithium elements in waste ternary lithium-ion battery materials are efficiently recycled and utilized to realize resource circulation.

[0007] The method provided by the present invention for recovering and separating nickel, cobalt and manganese from lithium slag extracted from waste ternary lithium-ion battery materials comprises the following steps:

[0008] 1) Acid leaching: The lithium slag from the waste ternary battery material is slurried and pumped into a leaching tank, and steam is introduced into the tank for direct heating, and then concentrated sulfuric acid is added for leaching. Compressed air is also introduced as an oxidant during the leaching process. After the leaching is completed, the solid and liquid are separated to obtain a leachate and a leaching residue;

[0009] 2) copper removal: the leachate obtained in step 1) is pumped into a copper removal tank, steam is introduced into the tank for direct heating, iron filings are added to remove copper, and after the copper removal is completed, liquid and solid are separated to obtain a copper-removed liquid;

[0010] 3) Removal of iron and aluminum: The copper-removed liquid obtained in step 2) is pumped to a plate heat exchanger for indirect heat exchange with steam to heat the solution to about 85-90° C. The solution after heat exchange flows to the iron-removal aluminum tank by gravity, and then the solution temperature is maintained at 85-90° C. by steam supplementary heat, and manganese carbonate slurry and hydrogen peroxide oxidant are added to remove iron and aluminum. After the iron and aluminum are removed, liquid and solid are separated to obtain an iron-removal aluminum liquid;

[0011] 4) Defluorination: the iron and aluminum-removed liquid obtained in step 3) is sent to a defluorination tank, a defluorination agent is added, and steam is introduced into the tank for direct heating. After the defluorination is completed, the liquid and solid are separated to obtain a defluorinated liquid;

[0012] 5) Extraction: The defluorinated liquid obtained in step 4) is subjected to filter pressing and then fine filtration to obtain a fine filtration liquid; the pH of the fine filtration liquid is adjusted to a set range, and then extracted with a P204 extractant containing nickel soap to obtain an organic-rich phase and a raffinate 1;

[0013] 6) Extracting manganese: extracting manganese from the raffinate 1 obtained in step 5) using a P204 extractant containing nickel soap to obtain a manganese-rich organic phase and a raffinate 2;

[0014] 7) Extracting cobalt: extracting cobalt from the raffinate 2 obtained in step 6) using a nickel soap-treated P507 extractant to obtain a cobalt-rich organic phase and a raffinate 3;

[0015] 8) Recovering nickel: The raffinate 3 obtained in step 7) is evaporated and crystallized to obtain nickel sulfate.

[0016] Since the process described in the present invention is a wet process, a large amount of water will be used in acid leaching and other processes. If the calcium and magnesium ions in the water are not controlled, emulsification may occur during the subsequent extraction and recovery of manganese, cobalt and nickel. Therefore, all water used in this process is subjected to hydrogen-type cation exchange resin for calcium and magnesium removal to reduce the content of calcium and magnesium ions.

[0017] Furthermore, in step 1), the leaching process conditions include: liquid-solid ratio of 4-8 ml:1 g, leaching temperature of 90-95° C., final acid pH of 1.5-2, and leaching time of 2-3 hours. During the leaching process, compressed air is introduced as an oxidant to oxidize the low-valent metal elements into high-valent metal elements to facilitate the reaction. The reactions involved are as follows:

[0018] (Ni x Co y Mn z)O+H2SO4=xNiSO4+yCoSO4+zMnSO4+H2O

[0019] Among them, x+y+z=1.

[0020] The waste ternary lithium-ion battery material powder usually obtained by mechanical disassembly contains a small amount of current collector copper foil and aluminum foil, and the lithium-ion battery electrolyte solute is composed of fluoride-containing salts. Therefore, before recovering nickel, cobalt and manganese elements in lithium slag, the leaching solution needs to be treated to remove impurities.

[0021] Furthermore, in step 2), the amount of iron filings added is 1.05 to 1.3 times the theoretical amount; the process conditions for copper removal include: reaction temperature of 75 to 80°C, pH at the start of the reaction = 1.5 to 2, pH at the end of the reaction = 2 to 3, and reaction time of 2 to 3 hours. The reactions involved are as follows:

[0022] Fe+CuSO4→FeSO4+Cu

[0023] Furthermore, in step 3), the amount of manganese carbonate and hydrogen peroxide added is 1.05 to 1.3 times the theoretical amount; the process conditions for removing iron and aluminum include: pH at the start of the reaction = 2 to 3, pH at the end of the reaction = 4.5 to 5, and the reaction time is 4 to 5 hours. The reactions involved are as follows:

[0024] 4FeSO4+4MnCO3+2H2O2+4H2O=4Fe(OH)3+4MnSO4+4CO2

[0025] Al2(SO4)3+3MnCO3+3H2O=2Al(OH)3+3MnSO4+3CO2

[0026] Furthermore, in step 4), the defluorination agent is a rare earth type adsorbent, preferably a silica gel adsorbent wrapped with a lanthanum oxide film; the defluorination process conditions include: reaction temperature of 75-80°C, pH at the start of the reaction = 4.5-5, pH at the end of the reaction = 5-6, and reaction time of 2-3h.

[0027] In addition to nickel, cobalt and manganese, the main impurities in the leachate are copper, aluminum, iron, fluorine and other elements. Under the condition of pH = 1.5-2, the copper ions in the solution are preferentially replaced by iron filings as a single substance, and the excess iron filings will react with the acid in the solution, and the iron enters the solution in the form of ions; then, manganese carbonate is added as a neutralizer and hydrogen peroxide as an oxidant to oxidize the iron in the solution to Fe 3+ , and at the end point of the reaction condition of pH=4.5-5.0, iron and aluminum are removed by hydrolysis precipitation; finally, an adsorption type defluorinating agent is used to remove fluorine in the solution. The impurity removal process of the present invention ensures the impurity removal effect while not introducing new impurity elements.

[0028] In order to separate the transition metals in the defluorinated liquid, P204 extractant after nickel soap is used to extract Mn, and P507 extractant after nickel soap is used to extract cobalt. P204 and P507 extractants are acidic extractants, and the following reactions mainly occur during the reaction process:

[0029] M n+ +nHA=MA n +nH +

[0030] In the above formula, HA represents the extractant P204 or P507, and M represents the metal element. As the reaction proceeds, the acidity of the solution gradually increases, inhibiting the forward reaction. To avoid this unfavorable factor, P204 and P507 are usually saponified before use. The commonly used process is to use NaOH to react with P204 and P507, and then extract after saponification. The reaction equation is as follows:

[0031] NaOH+HA=NaA+H2O

[0032] M n+ +nNaA=MA n +nNa +

[0033] In this process, after NaOH reacts with P204 and P507, nickel sulfate obtained in step 8) is used to react with sodium soaped P204 and P507 to make nickel soap. The saponification rate of sodium soap and nickel soap is 60% to 75%. The reaction equation of nickel soap process is as follows:

[0034] Ni 2+ +2NaA=NiA2+2Na +

[0035] The order of metal extraction by P204 is Fe 3+ 、Zn 2+ 、Al 3+ , Cu 2+ , Mn 2+ 、Co 2+ 、Ni 2+ In order to further remove trace elements such as iron, aluminum, and copper from the finely filtered liquid, P204 nickel soap was used for extraction.

[0036] Furthermore, in step 5), the pH setting range is 3-4; the extraction ratio of P204 extractant after nickel soap is O:A=1:50-80, and the extraction level is 6-8.

[0037] Preferably, in step 5) and step 6), the preparation of the P204 extractant after nickel soap includes multi-stage sodium soap, nickel soap, and sodium washing, specifically including: mixing P204 and sulfonated kerosene, controlling the volume concentration of P204 to be 25-30%, mixing it with sodium hydroxide solution for sodium soap, with O:A=28-32:1, sodium soap level 2-3, and controlling the saponification rate to be 60%-70%; then using nickel sulfate for nickel soap, with O:A=6-8:1, nickel soap level 3-5; finally using pure water for sodium washing, with O:A=28-32:1, sodium washing level 2-3.

[0038] Further, the organic-rich phase obtained in step 5) is sequentially stripped, iron-removed, washed, and saponified, specifically comprising: firstly stripping the organic-rich phase with 3-4 mol / L dilute sulfuric acid to obtain a stripping solution and an organic phase, wherein the stripping phase ratio is O:A=1-2:1, and the stripping stage is 8-10; the stripping solution is returned to the leaching process after being deoiled by ultrasound and activated carbon; then, 4-6 mol / L hydrochloric acid or 5%-10% oxalic acid is used to remove iron from the organic phase, the iron removal phase ratio is O:A=1-3:1, and the iron removal stage is 2-3; then, pure water is used for washing, the washing phase ratio is O:A=30-60:1, and the washing stage is 2-3; finally, sodium soap and nickel soap are performed.

[0039] Furthermore, in step 6), the nickel soap-treated P204 extractant is used to extract manganese with a relative ratio of O:A=0.5-3:1 and a manganese extraction level of 6-8.

[0040] Further, the manganese-rich organic phase obtained in step 6) is washed with 0.5-1 mol / L sulfuric acid, the acid washing phase ratio O:A=18-25:1, the acid washing stage is 6-8, and the acid washing liquid is returned to the P204 extraction and recovery of manganese step as an extraction stock solution; 4-6 mol / L sulfuric acid is used to strip manganese from the manganese-rich organic phase, the stripping phase ratio O:A=3-8:1, the stripping stage is 8-10, and a manganese stripping solution and an organic phase are obtained; the manganese stripping solution is then deoiled by ultrasonic wave and activated carbon and then sent to evaporation and crystallization to prepare manganese sulfate; the organic phase is washed with pure water, the washing phase ratio O:A=30-60:1, the washing stage is 2-3, and finally sodium soap and nickel soap are added to obtain nickel soap P204.

[0041] Furthermore, in step 7), the nickel soap-treated P507 extractant is used to extract the cobalt at a ratio of O:A=0.5-3:1, and the cobalt extraction level is 6-8.

[0042] Preferably, in step 7), the preparation of the P507 extractant after nickel soap includes multi-stage sodium soap, nickel soap, and sodium washing, specifically including: mixing P507 and sulfonated kerosene, controlling the volume concentration of P507 to 25-30%, mixing it with sodium hydroxide solution for sodium soap, with an O:A ratio of 28-32:1, a sodium soap level of 2-3, and a saponification rate of 60%-70%; then using nickel sulfate for nickel soap, with an O:A ratio of 6-8:1, and a nickel soap level of 3-5; finally, using pure water for sodium washing, with an O:A ratio of 28-32:1, and a sodium washing level of 2-3.

[0043] Further, the cobalt-rich organic phase obtained in step 7) is washed with 0.5-1 mol / L sulfuric acid, the acid washing phase ratio O:A=18-25:1, the acid washing stage is 6-8, and the acid washing liquid is returned to the P507 extraction and recovery of cobalt step as an extraction stock solution; the cobalt-rich organic phase is stripped of cobalt with 4-6 mol / L sulfuric acid, the stripping phase ratio O:A=3-8:1, the stripping stage is 8-10, and a cobalt stripping solution and an organic phase are obtained; the cobalt stripping solution is deoiled by ultrasound and activated carbon and then sent to evaporation and crystallization to prepare cobalt sulfate; the organic phase is washed with pure water, the washing phase ratio O:A=30-60:1, the washing stage is 2-3, and finally sodium soap and nickel soap are added to obtain nickel soap P507.

[0044] Beneficial effects of the present invention:

[0045] The present invention uses lithium slag extracted from waste ternary lithium-ion battery materials as raw materials, obtains an extract solution for extracting and separating transition metals nickel, cobalt and manganese through an acid leaching-impurity removal process, and adopts a nickel soap process for extraction. Only P204 impurity extraction, P204 manganese extraction and P507 cobalt extraction are required to obtain manganese sulfate, cobalt sulfate and nickel sulfate solutions. Compared with the conventional sodium soap extraction and recovery process, the P507 nickel extraction process is reduced, the investment in extraction equipment and the consumption of extractants are reduced, and at the same time, the amount of sodium-containing wastewater generated by the entire process is greatly reduced. The present invention has the following advantages:

[0046] 1. All water used in the process is treated with hydrogen-type cation exchange resin to remove calcium and magnesium, eliminating the effects of calcium and magnesium on the extraction process and product purity from the source.

[0047] 2. The entire impurity removal process does not introduce new impurity elements. The use of iron powder to remove copper does not introduce new impurity elements except for the iron element already in the acid leaching solution; at the same time, the subsequent use of manganese carbonate to remove iron and aluminum does not introduce new impurities compared to other neutralizers such as limestone and lime; the use of adsorbents to remove fluorine also does not introduce new impurities.

[0048] 3. The impurity removal effect is good. After the impurity removal, except for nickel, cobalt and manganese elements, other impurity elements such as copper, iron, aluminum, fluorine, calcium, magnesium, etc. are reduced to ppm level. The subsequent process can recycle battery-grade manganese sulfate, cobalt sulfate and nickel sulfate products, realizing the high-value utilization of nickel, cobalt and manganese elements in waste ternary lithium-ion battery materials.

[0049] 4. The extraction and recovery process produces less sodium-containing wastewater that needs to be treated, and the consumption of extraction agent is low, which can reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a process flow chart of the present invention.

[0051] Figure 2 The order of metal extraction by P204 at different pH values. DETAILED DESCRIPTION

[0052] Example 1

[0053] The mass percentage contents of the main metal elements in the lithium slag raw materials for extracting waste ternary lithium-ion battery materials are as follows: Ni 28.45%, Co 9.51%, Mn 8.92%, Al 0.95%, Cu 0.58%, and Fe 0.06%.

[0054] 1. Lithium slag leaching from waste ternary battery materials:

[0055] The lithium slag from the waste ternary battery materials is slurried and pumped into the leaching tank. Steam is introduced into the tank for direct heating, and then concentrated sulfuric acid is added for leaching. The liquid-solid ratio is controlled to be 4ml:1g, the leaching temperature is 90°C, and compressed air is introduced as an oxidant to oxidize the low-valent metal elements into high-valent metal elements to facilitate the reaction. The final acid pH is 2.0, and the reaction time is 2.5h. After the leaching is completed, the slurry is pumped to the leaching filter press for filtration. The leaching liquid obtained after liquid-solid separation flows by gravity into the post-leaching liquid storage tank. The leached slag is washed three times and then regularly outsourced for disposal. The main metal ion content in the leaching liquid is Ni 2+ 70.41g / L, Co 2+ 23.54g / L, Mn 2+ 22.08g / L、Al 3+ 1.88g / L, Cu 2+ 1.15g / L, Fe 3+ 0.15g / L, F - 25mg / L.

[0056] 2. Leachate impurity removal (removal of copper, iron, aluminum, and fluorine):

[0057] The leaching liquid is pumped into the copper removal tank, and iron powder is added in an amount of 1.1 times the theoretical amount of iron filings required for copper removal. At the same time, steam is introduced into the tank for direct heating, and the reaction temperature is maintained at 80°C for 2 hours. After copper removal, the slurry is pumped to the copper removal filter press for filtration. The copper removal liquid obtained after liquid-solid separation flows into the copper removal liquid storage tank by gravity. The copper slag is washed, filtered, and then stored and regularly outsourced for disposal. The pH of the copper removal liquid is 2.6, and the main metal ion content is Ni 2+ 70.41g / L, Co 2+ 23.54g / L, Mn 2+ 22.08g / L、Al 3+ 1.88g / L, Cu 2+ 5mg / L, Fe 2+ 1.26g / L, F - 25mg / L.

[0058] The copper-removed liquid is pumped to a plate heat exchanger for indirect heat exchange with steam to heat the solution to 90°C. The solution after heat exchange flows to the iron-aluminum removal tank by gravity, and then the solution temperature is maintained at 90°C by steam supplementary heat. Manganese carbonate slurry and hydrogen peroxide are added in an amount of 1.05 times the theoretical amount. The reaction is carried out for 4.5 hours, and the pH value of the reaction endpoint is controlled to be 4.5. After the iron-aluminum removal is completed, the slurry is pumped to the iron-aluminum removal filter press for filtration. The iron-aluminum removal liquid obtained after liquid-solid separation flows by gravity into the iron-aluminum removal liquid storage tank. The iron-aluminum slag is washed three times and then stored and regularly outsourced for disposal. The main metal ion content in the iron-aluminum removal liquid is Ni 2+ 70.41g / L, Co 2+ 23.54g / L, Mn 2+ 29.65g / L、Al 3+ 8mg / L, Cu 2+ 5mg / L, Fe 3+ 22mg / L, F - 25mg / L.

[0059] The liquid after iron and aluminum removal is sent to the defluorination tank, and a silica gel adsorbent wrapped with a lanthanum oxide film is added to remove fluorine. The amount of adsorbent added is calculated based on the adsorption capacity of 3.5 mg fluorine / 1g adsorbent. At the same time, steam is introduced into the tank for direct heating. The reaction temperature is 80°C, the reaction end point pH = 5.5, and the reaction time is 2.5 hours. After the defluorination is completed, the slurry is pumped to the defluorination filter press for two-stage filtration. The defluorinated liquid obtained after liquid-solid separation flows into the defluorinated liquid storage tank by gravity, and the fluorine residue is regularly outsourced for disposal. The fluorine content in the defluorinated liquid is less than 1 mg / L. After two stages of filtration, it enters the precision filter for fine filtration. The finely filtered liquid is pumped to the pH adjustment tank, sulfuric acid is added to adjust the pH to 3.5, and then sent to the subsequent extraction. The main metal ion content in the original extraction solution is Ni 2+ 70.41g / L, Co 2+ 23.54g / L, Mn2+ 29.65g / L、Al 3+ 8mg / L, Cu 2+ 5mg / L, Fe 3+ 22mg / L.

[0060] 3. Mixture

[0061] The extraction is carried out in an extraction box, which is equipped with multi-stage sodium soap, nickel soap, sodium washing, extraction, stripping, iron removal, and water washing in sequence, with an operating temperature of 35°C. First, sodium hydroxide is used to make 30% P204 + 70% sulfonated kerosene sodium soap, with a saponification rate of 70%, a relative ratio of O:A = 30:1, and a sodium soap level of 2; then the nickel sulfate produced by the project is used for nickel soap, with a relative ratio of O:A = 7:1, and a nickel soap level of 3; finally, pure water is used for sodium washing, with a relative ratio of O:A = 30:1, and a sodium washing level of 2, to obtain the P204 extractant after nickel soap. The extraction ratio of the P204 extractant after nickel soap is O:A = 1:50, the extraction level is 7, and the phases are separated to obtain an organic-rich phase and a raffinate 1; then, the raffinate 1 is sent to P204 for extraction and recovery of manganese. The main metal ion concentration in the raffinate 1 is Ni 2+ 70.78g / L, Co 2+ 23.54g / L, Mn 2+ 29.37g / L,Al 3+ , Fe 3+ , Cu 2+ The ion concentration is less than 1mg / L; 4mol / L sulfuric acid is used to strip the rich organic phase, the stripping phase ratio is O:A=1:1, the stripping stage is 10, and the phases are separated to obtain the stripping solution and the organic phase. The stripping solution is returned to the leaching process after ultrasonic and activated carbon oil removal; 6mol / L hydrochloric acid is used to remove iron from the organic phase, the iron removal phase ratio is O:A=3:1, and the iron removal stage is 3; then pure water is used for water washing, the water washing phase ratio is O:A=30:1, the water washing stage is 2, and finally sodium soap and nickel soap are used to obtain nickel soap P204.

[0062] 4. Extraction and recovery of manganese

[0063] The extraction and recovery of manganese is carried out in an extraction box, which is equipped with multi-stage sodium soap, nickel soap, sodium washing, extraction, acid washing, stripping, iron removal, and water washing in sequence, and the operating temperature is 35°C. First, sodium hydroxide is used to make 30% P204 + 70% sulfonated kerosene sodium soap, with a saponification rate of 70%, a relative ratio of O:A = 30:1, and a sodium soap level of 2; then the nickel sulfate produced by the project is used for nickel soap, with a relative ratio of O:A = 7:1, and a nickel soap level of 3; finally, pure water is used for sodium washing, with a relative ratio of O:A = 30:1, a sodium washing level of 2, and the P204 extractant after nickel soap is obtained; the P204 extractant after nickel soap is used to extract manganese with a relative ratio of O:A = 1.75:1, and a manganese extraction level of 8, and phase separation is performed to obtain a manganese-rich organic phase and a raffinate 2. Next, the raffinate 2 is sent to P507 for extraction and recovery of cobalt. The main metal ion concentration in the raffinate 2 is Ni 2+ 103.48g / L, Co 2+ 22.86g / L, Mn 2+ The ion concentration is less than 1 mg / L; the manganese-rich organic phase is washed with 0.5 mol / L sulfuric acid, the pickling phase ratio is O:A=25:1, the pickling stage is 7, and the pickling liquid is returned to the P204 extraction and recovery process for manganese as the extraction stock solution; the manganese-rich organic phase is stripped with 4 mol / L sulfuric acid, the stripping phase ratio is O:A=6:1, the stripping stage is 10, and the manganese stripping solution and the organic phase are obtained by phase separation; the metal ion concentration Ni in the manganese stripping solution 2+ 0.001g / L, Co 2+ 0.001g / L, Mn 2+ 97.90g / L, after ultrasonic and activated carbon degreasing, it was sent to evaporation crystallization to prepare manganese sulfate. It was washed with pure water, the washing ratio O:A=30:1, the washing level was 2, and finally sodium soap and nickel soap were made to obtain nickel soap P204.

[0064] 5. Extraction and recovery of cobalt

[0065] The extraction and recovery of cobalt is carried out in an extraction box, which is equipped with multi-stage sodium soap, nickel soap, sodium washing, extraction, acid washing, stripping and water washing in sequence, and the operating temperature is 35°C. First, 30% P507 + 70% sulfonated kerosene sodium soap is made with sodium hydroxide, with a relative ratio of O:A = 30:1 and a sodium soap level of 2; then, nickel sulfate produced by the project is used for nickel soap, with a relative ratio of O:A = 7:1 and a nickel soap level of 3; finally, pure water is used for sodium washing, with a relative ratio of O:A = 30:1 and a sodium washing level of 2 to obtain the P507 extractant after nickel soap; the P507 extractant after nickel soap is used to extract cobalt with a relative ratio of O:A = 1.25:1 and a cobalt extraction level of 7, and phase separation is performed to obtain a cobalt-rich organic phase and raffinate 3. Ni in raffinate 3 2+ 126.34g / L, Co 2+0.005g / L, after ultrasonic and activated carbon deoiling, it was sent to evaporation crystallization to prepare nickel sulfate; 0.5mol / L sulfuric acid was used to wash the cobalt-rich organic phase, the pickling phase ratio O:A=25:1, the pickling level was 7, and the pickling liquid was returned to the P507 extraction and recovery of cobalt process as the extraction stock solution; 4mol / L sulfuric acid was used to strip cobalt from the cobalt-rich organic phase, the stripping phase ratio O:A=6:1, the stripping level was 10, and the cobalt stripping solution and organic phase were obtained. The metal ion concentration in the cobalt stripping solution is Ni 2+ 0.001g / L, Co105.05g / L, after ultrasonic and activated carbon degreasing, sent to evaporation crystallization to prepare cobalt sulfate. Use pure water to wash the organic phase, the washing phase ratio O:A=30:1, the washing level is 2, and finally sodium soap and nickel soap are carried out to obtain nickel soap P507.

[0066] 6. Nickel sulfate / cobalt sulfate / manganese sulfate evaporation crystallization

[0067] The nickel sulfate, cobalt sulfate and manganese sulfate solutions produced in the extraction process are stored in nickel sulfate, cobalt sulfate and manganese sulfate solution storage tanks respectively. Nickel sulfate, cobalt sulfate and manganese sulfate solutions are subjected to evaporation crystallization, centrifugal dehydration, drying and other processes to obtain nickel sulfate, cobalt sulfate and manganese sulfate products. The crystallized mother liquor is pumped into the evaporation system or returned to the purification process.

[0068] Example 2

[0069] The mass percentage contents of the main metal elements in the lithium slag raw materials for extracting waste ternary lithium-ion battery materials are as follows: Ni 33.26%, Co 7.13%, Mn 6.61%, Al 1.23%, Cu 0.95%, and Fe 0.05%.

[0070] 1. Lithium slag leaching from waste ternary battery materials:

[0071] The lithium slag from the waste ternary battery materials is slurried and pumped into the leaching tank. Steam is introduced into the tank for direct heating, and then concentrated sulfuric acid is added for leaching. The liquid-solid ratio is controlled to be 5ml:1g, the leaching temperature is 90°C, and compressed air is introduced as an oxidant. The final acid pH is 2.0 and the reaction time is 2h. After the leaching is completed, the slurry is pumped to the leaching filter press for filtration. The leaching liquid obtained after liquid-solid separation flows by gravity into the post-leaching liquid storage tank. The leached slag is washed three times and then regularly outsourced for disposal. The main ion content in the leaching liquid is Ni 2+ 65.85g / L, Co 2+ 14.12g / L, Mn 2+ 13.09g / L、Al 3+ 1.94g / L, Cu 2+ 1.50g / L, Fe 3+ 0.1g / L, F - 21mg / L.

[0072] 2. Leachate impurity removal (removal of copper, iron, aluminum, and fluorine):

[0073] The leaching liquid is pumped into the copper removal tank, and iron powder is added in an amount of 1.1 times the theoretical amount of iron filings required for copper removal. At the same time, steam is introduced into the tank for direct heating, and the reaction temperature is maintained at 80°C. The reaction time is 3 hours. After copper removal, the slurry is pumped to the copper removal filter press for filtration. The copper removal liquid obtained after liquid-solid separation flows into the copper removal liquid storage tank by gravity. The copper slag is washed, filtered, and then stored and regularly outsourced for disposal. The pH of the copper removal liquid is 2.8, and the main ion content is Ni 2+ 65.85g / L, Co 2+ 14.12g / L, Mn 2+ 13.09g / L、Al 3+ 1.94g / L, Cu 2+ 4mg / L, Fe 2+ 1.54g / L, F - 21mg / L.

[0074] The copper-removed liquid is pumped to a plate heat exchanger for indirect heat exchange with steam to heat the solution to 85°C. The solution after heat exchange flows to the iron-aluminum removal tank by gravity, and then the solution temperature is maintained at 85°C by steam supplementary heat. Manganese carbonate slurry and hydrogen peroxide are added in an amount of 1.1 times the theoretical amount. The reaction is carried out for 5 hours, and the pH value of the reaction endpoint is controlled to be 4.5. After the iron-aluminum removal is completed, the slurry is pumped to the iron-aluminum removal filter press for filtration. The iron-aluminum removal liquid obtained after liquid-solid separation flows by gravity into the iron-aluminum removal liquid storage tank. The iron-aluminum slag is washed three times and then stored and regularly outsourced for disposal. The metal ion content in the iron-aluminum removal liquid is Ni 2+ 65.85g / L, Co 2 + 14.12g / L, Mn 2+ 21.27g / L、Al 3+ 6mg / L, Cu 2+ 4mg / L, Fe 3+ 18mg / L, F - 21mg / L.

[0075] The liquid after iron and aluminum removal is sent to the defluorination tank, and a silica gel adsorbent wrapped with a lanthanum oxide film is added to remove fluorine. The amount of adsorbent added is calculated based on the adsorption capacity of 3.5 mg fluorine / 1 g adsorbent. At the same time, steam is introduced into the tank for direct heating. The reaction temperature is 80°C, the reaction end point pH = 5.5, and the reaction time is 3 hours. After the defluorination is completed, the slurry is pumped to the defluorination filter press for two-stage filtration. The defluorinated liquid obtained after liquid-solid separation flows into the defluorinated liquid storage tank by gravity, and the fluorine residue is regularly outsourced for disposal. The fluorine content in the defluorinated liquid is less than 1 mg / L. After two stages of filtration, it enters the precision filter for fine filtration. The finely filtered liquid is pumped to the pH adjustment tank, sulfuric acid is added to adjust the pH to 3.5, and then sent to the subsequent extraction. The metal ion content in the original extraction solution is Ni 2+ 65.85g / L, Co 2+ 14.12g / L, Mn 2+ 21.27g / L、Al 3+ 6mg / L, Cu 2+ 4mg / L, Fe 3+ 18mg / L.

[0076] 3. Mixture

[0077] The extraction is carried out in an extraction box, which is equipped with multi-stage sodium soap, nickel soap, sodium washing, extraction, stripping, iron removal, and water washing in sequence, with an operating temperature of 35°C. First, sodium hydroxide is used to make 30% P204 + 70% sulfonated kerosene sodium soap, with a saponification rate of 70%, a relative ratio of O:A = 30:1, and a sodium soap level of 2; then the nickel sulfate produced by the project is used for nickel soap, with a relative ratio of O:A = 7:1, and a nickel soap level of 3; finally, pure water is used for sodium washing, with a relative ratio of O:A = 30:1, and a sodium washing level of 2, to obtain the P204 extractant after nickel soap. The extraction of the P204 extractant after nickel soap is compared with O:A = 1:50, with an extraction level of 7, and phase separation is performed to obtain an organic-rich phase and a raffinate 1; then, the raffinate 1 is sent to P204 for extraction and recovery of manganese. The concentration of the main metal ions in the raffinate 1 is Ni 2+ 66.22g / L, Co 2+ 14.12g / L, Mn 2+ 20.97g / L,Al 3+ , Fe 3+ , Cu 2+ The ion concentration is less than 1mg / L; 4mol / L sulfuric acid is used to strip the rich organic phase, the stripping phase ratio is O:A=1:1, the stripping stage is 10, and the phases are separated to obtain the stripping solution and the organic phase. The stripping solution is returned to the leaching process after ultrasonic and activated carbon oil removal; 6mol / L hydrochloric acid is used to remove iron from the organic phase, the iron removal phase ratio is O:A=3:1, and the iron removal stage is 3; then pure water is used for water washing, the water washing phase ratio is O:A=30:1, the water washing stage is 2, and finally sodium soap and nickel soap are used to obtain nickel soap P204.

[0078] 4. Extraction and recovery of manganese

[0079] The extraction and recovery of manganese is carried out in an extraction box, which is equipped with multi-stage sodium soap, nickel soap, sodium washing, extraction, acid washing, stripping, iron removal, and water washing in sequence, and the operating temperature is 35°C. First, sodium hydroxide is used to make 30% P204 + 70% sulfonated kerosene sodium soap, with a saponification rate of 70%, a relative ratio of O:A = 30:1, and a sodium soap level of 2; then the nickel sulfate produced by the project is used for nickel soap, with a relative ratio of O:A = 7:1, and a nickel soap level of 3; finally, pure water is used for sodium washing, with a relative ratio of O:A = 30:1, a sodium washing level of 2, and the P204 extractant after nickel soap is obtained; the P204 extractant after nickel soap is used to extract manganese with a relative ratio of O:A = 1.25:1, and a manganese extraction level of 8, and phase separation is performed to obtain a manganese-rich organic phase and a raffinate 2. Next, the raffinate 2 is sent to P507 for extraction and recovery of cobalt. The main metal ion concentration in the raffinate 2 is Ni 2+ 89.58g / L, Co 2+ 13.25g / L, Mn 2+ The ion concentration is less than 1 mg / L; the manganese-rich organic phase is washed with 0.5 mol / L sulfuric acid, the pickling phase ratio is O:A=25:1, the pickling stage is 7, and the pickling liquid is returned to the P204 extraction and recovery process for manganese as the extraction stock solution; the manganese-rich organic phase is stripped of manganese with 4 mol / L sulfuric acid, the stripping phase ratio is O:A=7:1, the stripping stage is 10, and the manganese stripping solution and the organic phase are obtained by phase separation; the metal ion concentration Ni in the manganese stripping solution 2+ 0.001g / L, Co 2+ 0.001g / L, Mn 2+ 114.28g / L, after ultrasonic and activated carbon degreasing, sent to evaporation crystallization to prepare manganese sulfate. Use pure water for water washing, the water washing ratio O:A=30:1, the water washing level is 2, and finally sodium soap and nickel soap are used to obtain nickel soap P204.

[0080] 5. Extraction and recovery of cobalt

[0081] The extraction and recovery of cobalt is carried out in an extraction box, which is equipped with multi-stage sodium soap, nickel soap, sodium washing, extraction, acid washing, stripping and water washing in sequence, and the operating temperature is 35°C. First, 30% P507 + 70% sulfonated kerosene sodium soap is made with sodium hydroxide, with a relative ratio of O:A = 30:1 and a sodium soap level of 2; then, nickel sulfate produced by the project is used for nickel soap, with a relative ratio of O:A = 7:1 and a nickel soap level of 3; finally, pure water is used for sodium washing, with a relative ratio of O:A = 30:1 and a sodium washing level of 2 to obtain the P507 extractant after nickel soap; the P507 extractant after nickel soap is used to extract cobalt with a relative ratio of O:A = 0.75:1 and a cobalt extraction level of 7, and phase separation is performed to obtain a cobalt-rich organic phase and raffinate 3. Ni in raffinate 3 2+ 102.83g / L, Co 2+0.004g / L, after ultrasonic and activated carbon deoiling, it was sent to evaporation crystallization to prepare nickel sulfate; 0.5mol / L sulfuric acid was used to wash the cobalt-rich organic phase, the pickling phase ratio O:A=20:1, the pickling level was 7, and the pickling liquid was returned to the P507 extraction and recovery of cobalt process as the extraction stock solution; 4mol / L sulfuric acid was used to strip cobalt from the cobalt-rich organic phase, the stripping phase ratio O:A=7:1, the stripping level was 10, and the cobalt stripping solution and organic phase were obtained. The metal ion concentration in the cobalt stripping solution is Ni 2+ 0.001g / L, Co 2 + 120.47g / L, after ultrasonic and activated carbon degreasing, it was sent to evaporation crystallization to prepare cobalt sulfate. The organic phase was washed with pure water, the washing phase ratio O:A=30:1, the washing level was 2, and finally sodium soap and nickel soap were made to obtain nickel soap P507.

[0082] 6. Nickel sulfate / cobalt sulfate / manganese sulfate evaporation crystallization

[0083] The nickel sulfate, cobalt sulfate and manganese sulfate solutions produced in the extraction process are stored in nickel sulfate, cobalt sulfate and manganese sulfate solution storage tanks respectively. Nickel sulfate, cobalt sulfate and manganese sulfate solutions are subjected to evaporation crystallization, centrifugal dehydration, drying and other processes to obtain nickel sulfate, cobalt sulfate and manganese sulfate products. The crystallized mother liquor is pumped into the evaporation system or returned to the purification process.

[0084] Table 1 Raw material composition of lithium slag from waste ternary lithium-ion battery materials

[0085]

[0086] Table 2 Acid leaching liquid composition

[0087]

[0088] Table 3 Main ingredients of the products

[0089]

[0090]

Claims

1. A method for recovering and separating nickel, cobalt and manganese from lithium slag extracted from waste ternary lithium-ion battery materials, comprising the following steps: 1) Acid leaching: The lithium slag from the waste ternary battery material is slurried and pumped into a leaching tank, and steam is introduced into the tank for direct heating, and then concentrated sulfuric acid is added for leaching. Compressed air is also introduced as an oxidant during the leaching process. After the leaching is completed, the solid and liquid are separated to obtain a leachate and a leaching residue; 2) copper removal: the leachate obtained in step 1) is pumped into a copper removal tank, steam is introduced into the tank for direct heating, iron filings are added to remove copper, and after the copper removal is completed, liquid and solid are separated to obtain a copper-removed liquid; 3) Removal of iron and aluminum: The copper-removed liquid obtained in step 2) is pumped to a plate heat exchanger for indirect heat exchange with steam to heat the solution to about 85-90° C. The solution after heat exchange flows to the iron-removal aluminum tank by gravity, and then the solution temperature is maintained at 85-90° C. by steam supplementary heat, and manganese carbonate slurry and hydrogen peroxide oxidant are added to remove iron and aluminum. After the iron and aluminum are removed, liquid and solid are separated to obtain an iron-removal aluminum liquid; 4) Defluorination: the de-iron and de-aluminum liquid obtained in step 3) is sent to a defluorination tank, a defluorination agent is added, and steam is introduced into the tank for direct heating. After the defluorination is completed, the liquid and solid are separated to obtain a de-fluorinated liquid; 5) Extraction: The defluorinated liquid obtained in step 4) is subjected to filter pressing and then fine filtration to obtain a fine filtration liquid; the pH of the fine filtration liquid is adjusted to a set range, and then extracted with a P204 extractant containing nickel soap to obtain an organic-rich phase and a raffinate 1; 6) Extracting manganese: extracting manganese from the raffinate 1 obtained in step 5) using a P204 extractant containing nickel soap to obtain a manganese-rich organic phase and a raffinate 2; 7) Extracting cobalt: extracting cobalt from the raffinate 2 obtained in step 6) using a nickel soap-treated P507 extractant to obtain a cobalt-rich organic phase and a raffinate 3; 8) Recovering nickel: The raffinate 3 obtained in step 7) is evaporated and crystallized to obtain nickel sulfate.

2. The method according to claim 1, characterized in that: In step 1), the leaching process conditions include: liquid-solid ratio of 4-8 ml:1 g, leaching temperature of 90-95° C., final acid pH of 1.5-2, and leaching time of 2-3 h.

3. The method according to claim 1, characterized in that: In step 2), the amount of iron filings added is 1.05 to 1.3 times the theoretical amount; the process conditions for copper removal include: reaction temperature of 75 to 80°C, pH at the start of the reaction = 1.5 to 2, pH at the end of the reaction = 2 to 3, and reaction time of 2 to 3 hours; In step 3), the amount of manganese carbonate and hydrogen peroxide added is 1.05 to 1.3 times the theoretical amount; the process conditions for removing iron and aluminum include: pH at the start of the reaction = 2 to 3, pH at the end of the reaction = 4.5 to 5, and the reaction time is 4 to 5 hours; In step 4), the defluorination agent is a rare earth type adsorbent, preferably a silica gel adsorbent wrapped with a lanthanum oxide film; the defluorination process conditions include: reaction temperature of 75-80°C, pH at the start of the reaction = 4.5-5, pH at the end of the reaction = 5-6, and reaction time of 2-3h.

4. The method according to claim 1, characterized in that: In step 5), the pH setting range is 3 to 4; the extraction ratio of P204 extractant after nickel soap is O:A=1:50 to 80, and the extraction level is 6 to 8; In step 6), the nickel soap-treated P204 extractant is used to extract manganese with a ratio of O:A=0.5-3:1 and a manganese extraction level of 6-8; In step 7), the nickel soap-treated P507 extractant is used to extract the cobalt at a ratio of O:A=0.5-3:1, and the cobalt extraction level is 6-8.

5. The method according to claim 1, characterized in that In step 5) and step 6), the preparation of the P204 extractant after nickel soap includes multi-stage sodium soap, nickel soap, and sodium washing, specifically including: mixing P204 and sulfonated kerosene, controlling the volume concentration of P204 to be 25-30%, mixing it with sodium hydroxide solution for sodium soap, with an O:A ratio of 28-32:1, a sodium soap level of 2-3, and a saponification rate of 60%-70%; then using nickel sulfate for nickel soap, with an O:A ratio of 6-8:1, and a nickel soap level of 3-5; finally, using pure water for sodium washing, with an O:A ratio of 28-32:1, and a sodium washing level of 2-3.

6. The method according to claim 1, characterized in that The organic-rich phase obtained in step 5) is sequentially subjected to stripping, iron removal, water washing and saponification, specifically comprising: firstly stripping the organic-rich phase with 3-4 mol / L dilute sulfuric acid to obtain a stripping solution and an organic phase, wherein the stripping phase ratio is O:A=1-2:1, and the stripping stage is 8-10; the stripping solution is returned to the leaching process after being deoiled by ultrasonic wave and activated carbon; then, the organic phase is stripped of iron with 4-6 mol / L hydrochloric acid or 5%-10% oxalic acid, the iron removal phase ratio is O:A=30-60:1, and the iron removal stage is 2-3; then, pure water is used for water washing, the washing phase ratio is O:A=1-3:1, and the washing stage is 2-3; finally, sodium soap and nickel soap are performed.

7. The method according to claim 1, characterized in that The manganese-rich organic phase obtained in step 6) is washed with 0.5-1 mol / L sulfuric acid, the acid washing phase ratio O:A=18-25:1, the acid washing stage is 6-8, and the acid washing liquid is returned to the P204 extraction and recovery of manganese process as an extraction stock solution; the manganese-rich organic phase is stripped of manganese with 4-6 mol / L sulfuric acid, the stripping phase ratio O:A=3-8:1, the stripping stage is 8-10, and a manganese stripping solution and an organic phase are obtained; the manganese stripping solution is then deoiled by ultrasonic wave and activated carbon and then sent to evaporation and crystallization to prepare manganese sulfate; the organic phase is washed with pure water, the washing phase ratio O:A=30-60:1, the washing stage is 2-3, and finally sodium soap and nickel soap are added to obtain nickel soap P204.

8. The method according to claim 1, characterized in that In step 7), the preparation of the P507 extractant after nickel soap includes multi-stage sodium soap, nickel soap, and sodium washing, specifically including: mixing P507 and sulfonated kerosene, controlling the volume concentration of P507 to 25-30%, mixing it with sodium hydroxide solution for sodium soap, with an O:A ratio of 28-32:1, a sodium soap level of 2-3, and a saponification rate of 60%-70%; then using nickel sulfate for nickel soap, with an O:A ratio of 6-8:1, and a nickel soap level of 3-5; finally, using pure water for sodium washing, with an O:A ratio of 28-32:1, and a sodium washing level of 2-3.

9. The method according to claim 1, characterized in that: The cobalt-rich organic phase obtained in step 7) is washed with 0.5-1 mol / L sulfuric acid, the acid washing phase ratio O:A=18-25:1, the acid washing stage is 6-8, and the acid washing liquid is returned to the P507 extraction and recovery process for use as an extraction stock solution; the cobalt-rich organic phase is stripped of cobalt with 4-6 mol / L sulfuric acid, the stripping phase ratio O:A=3-8:1, the stripping stage is 8-10, and a cobalt stripping solution and an organic phase are obtained; the cobalt stripping solution is deoiled by ultrasonic wave and activated carbon, and then sent to evaporation and crystallization to prepare cobalt sulfate; the organic phase is washed with pure water, the water washing phase ratio O:A=30-60:1, the water washing stage is 2-3, and finally sodium soap and nickel soap are added to obtain nickel soap P507.

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