Method for recovering waste residue generated by wet recovery of lithium battery positive electrode powder

Abstract

The present invention provides a method for recovering waste residues generated by wet recovery of lithium battery positive electrode powder. The recovery method comprises: dissolving a first metal-containing waste residue with a sulfuric acid aqueous solution, and heating and leaching the first solution, diluting the first solution with a diluent, and respectively dissolving a second metal-containing waste residue and a third metal-containing waste residue to obtain a second solution and a third solution; finally, mixing the second solution and the third solution to obtain a mixed solution, adding an initiator to trigger a fluorination reaction, and obtaining a nickel-cobalt-manganese-lithium recovery solution. The present invention cleverly combines the treatment of three main waste residues generated by hydrometallurgy. Through coordinated treatment, it not only solves the problem that waste residues generated in the hydrometallurgical recovery process are difficult to treat, but also achieves the maximum possible recovery of valuable metals at a very low cost. It is simple and easy to implement, more practical, and easy to achieve scientific, reasonable and efficient industrial application.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery recycling, and in particular to a method for recycling waste residue generated by wet recycling of lithium battery positive electrode powder. Background Art

[0002] At present, most of the waste lithium batteries are mainly treated by the wet recycling process. The wet recycling process is to discharge, crush, sort, screen and other steps of the waste lithium batteries to obtain positive electrode powder, and then use acid and reducing agent to leach nickel, cobalt, manganese and lithium metals from the positive electrode powder, and then add reagents to remove iron, aluminum, copper, calcium and magnesium to obtain a refined nickel, cobalt and manganese sulfate solution, which can then be used to synthesize positive electrode precursor materials.

[0003] The existing technology has no complete and effective solution for the waste slag produced by hydrometallurgical recovery of positive electrode powder. Figure 1 As shown, in the first step of the hydrometallurgical process, the valuable metals (nickel, cobalt, manganese, and lithium) are extracted in a free state by acid leaching (including inorganic acids and organic acids), and a reducing agent is added to increase the recovery rate of the valuable metals. No matter what kind of acid and reducing agent are used, some valuable metals cannot be extracted at one time. This is the first waste slag produced by hydrometallurgy - the first metal-containing waste slag. In order to improve the recovery rate of valuable metals and improve economic efficiency, it is necessary to perform a secondary leaching on the first metal-containing waste slag. The first metal-containing waste slag is characterized by a high content of binder and conductive agent. The conductive agent is generally conductive carbon black, acetylene black, Ketjen black, etc. This type of material generally has the characteristics of strong hydrophobicity and low density, and is difficult to process. There is no good solution in the market at present. When performing the secondary leaching according to the method of the first leaching, it is particularly easy to cause the phenomenon of material rushing when adding the reducing agent. In addition, the process of adding the reducing agent is more cumbersome, which increases the process cost.

[0004] In the second step, the removal of aluminum and iron impurities in the leachate is generally done by adding a pH adjusting agent for neutralization and hydrolysis, and separating the iron and aluminum elements from other ions in the form of hydroxide precipitation. This is the second waste slag produced by hydrometallurgy - the second metal-containing waste slag. When adjusting the pH, adding a pH adjusting agent can easily cause the local solution to become over-alkaline, precipitating nickel, cobalt and manganese, and then dissolving them. As the pH increases, the nickel, cobalt and manganese hydroxides dissolve more slowly, so the pH adjustment process will precipitate some nickel, cobalt and manganese together. At the same time, aluminum and iron are very likely to form amorphous colloids in the process of continuous precipitation-dissolution-precipitation. They have high water content and are difficult to filter. They are also easy to adsorb valuable metals such as nickel, cobalt, manganese and lithium, resulting in incomplete recovery. Because the second metal-containing waste slag contains a large amount of amorphous aluminum hydroxide, it absorbs more substances and contains some hydroxides produced by local over-alkalinity. Therefore, when the second metal-containing waste slag is treated alone, the iron and aluminum elements need to be separated. There is no good treatment plan at present. The effect of treating the second metal-containing waste slag alone is not good. The effect of alkali treatment of the second metal-containing waste slag is not good, resulting in unsatisfactory separation of aluminum and other valuable metal elements, and the inability to separate iron. When the aluminum content in the iron and aluminum removal solution is 5000ppm, the loss rate of nickel, cobalt, manganese and lithium is about 15%. It can be seen that it is very necessary to treat the second metal-containing waste slag, especially when the aluminum content in the positive electrode powder is high. It is more critical.

[0005] The third step is to remove copper with soluble sulfides (sodium sulfide, ammonium sulfide, potassium sulfide, etc.), which can selectively remove copper in depth and produce a small amount of waste slag, which can be directly processed to obtain a solution containing iron, aluminum and copper. Then, sodium hydroxide is added to the solution to separate nickel, cobalt and manganese from lithium ions in the form of precipitation. The nickel, cobalt and manganese precipitate is washed and dissolved to obtain a solution to be removed of calcium and magnesium.

[0006] The fourth step is that the calcium and magnesium content in the solution to be decalcified is generally below 300ppm. Fluoride (manganese fluoride and nickel fluoride) is usually added to the solution after copper removal to precipitate calcium and magnesium. When the solution contains a large amount of nickel and cobalt ions, the fluoride ions will form complex fluoride [NiF6] with the nickel and cobalt ions. 4- and [CoF6] 4-Etc., fluoride coordination ions are difficult to eliminate. Moreover, in the process of adding fluoride to remove calcium and magnesium, due to the interference of background metal ions, the amount of fluoride added needs to be much greater than the theoretical amount, so that the content of calcium and magnesium ions in the solution can be reduced to the requirements of the solution required to produce qualified products. Therefore, in order to deeply remove calcium and magnesium, the amount of fluoride added must be 2-7% of the mass fraction of the solution to be decalcified and magnesium. The specific amount added can be determined according to the content of calcium and magnesium. The amount of fluoride used will also be generated. This is the third waste slag produced by hydrometallurgy-the third metal-containing waste slag. When the third metal-containing waste slag is treated alone, although calcium fluoride and magnesium fluoride can be separated from nickel fluoride or manganese fluoride by acid, the resulting solution containing a large amount of fluoride ions is difficult to handle.

[0007] Patent CN 110373545 A discloses the use of alkali dissolution to treat the second metal-containing waste slag, but this method cannot separate the iron element from the nickel, cobalt and manganese elements. It usually takes multiple alkali dissolutions to convert the aluminum element into aluminate ions. The obtained alkali-soluble slag needs to be dissolved in acid again, and the obtained sodium aluminate needs to be treated separately. Patent CN 114214517 A requires the additional preparation of an aluminum-containing defluoridating agent to achieve the purpose of defluoridation, which increases the process flow and other costs. Patent CN 111455175A uses nickel fluoride or manganese fluoride to remove calcium and magnesium during the impurity removal process, and does not introduce other impurities, but rarely mentions other waste slags produced, and does not provide a solution to the waste slag. Summary of the invention

[0008] The main purpose of the present invention is to provide a method for recovering waste slag generated by wet metallurgical recovery of lithium battery positive electrode powder, so as to solve the problem that waste slag generated by wet metallurgical recovery of lithium battery positive electrode powder in the prior art is difficult to recover.

[0009] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a method for recovering waste residues generated by wet recovery of lithium battery positive electrode powder is provided, wherein the waste residues include a first metal-containing waste residue, a second metal-containing waste residue and a third metal-containing waste residue, wherein the first metal-containing waste residue contains nickel, cobalt, manganese and lithium elements; the second metal-containing waste residue contains iron, aluminum, nickel, cobalt, manganese and lithium elements; the third metal-containing waste residue contains fluorine, calcium, magnesium, nickel and manganese elements; the recovery method comprises the following steps: step S1, dissolving the first metal-containing waste residue with a sulfuric acid aqueous solution, and heating and leaching to obtain a first dissolving solution; step S2, diluting the first dissolving solution with a diluent to obtain a first dissolving solution diluent; dissolving the second metal-containing waste residue with the first dissolving solution diluent to obtain a second dissolving solution; dissolving the third metal-containing waste residue with the first dissolving solution diluent to obtain a third dissolving solution; step S3, mixing the second dissolving solution and the third dissolving solution to obtain a mixed solution; adding an initiator to the mixed solution to adjust the pH of the mixed solution to 4.5-5.1, and triggering a fluorination reaction to obtain a nickel-cobalt-manganese-lithium recovery solution.

[0010] Furthermore, in step S1, the mass concentration of the aqueous sulfuric acid solution is 30-50%; preferably, the mass ratio of the aqueous sulfuric acid solution to the first metal-containing waste slag is (10-20):1.

[0011] Furthermore, in step S1, the temperature of the heating leaching is 80-90° C., and the time is 1-3 hours.

[0012] Furthermore, in step S2, the diluent is water or a mixture of water and hydrogen peroxide.

[0013] Furthermore, in step S2, the volume ratio of the diluent to the first dissolving solution is (0.5-1):1.

[0014] Furthermore, in step S2, the pH of the second dissolving solution is less than 1, and the pH of the third dissolving solution is less than 2.

[0015] Furthermore, the second dissolving solution includes aluminum, and the third dissolving solution includes fluorine. In step S3, the second dissolving solution and the third dissolving solution are mixed according to a molar ratio of aluminum to fluorine of 1:(5.5-6.1).

[0016] Further, in step S3, the initiator includes one or more of a first initiator, a second initiator and a third initiator; wherein the first initiator includes sodium hydroxide and / or sodium carbonate, the second initiator includes potassium hydroxide and / or potassium carbonate, and the third initiator includes ammonia water and / or ammonium carbonate.

[0017] Furthermore, wet recovery uses a pH adjuster to remove iron and aluminum, and the pH adjuster includes one or more of a first pH adjuster, a second pH adjuster and a third pH adjuster; wherein the first pH adjuster includes one or more of sodium hydroxide, sodium carbonate and sodium bicarbonate, the second pH adjuster includes one or more of potassium hydroxide, potassium carbonate and potassium bicarbonate, and the third pH adjuster includes one or more of ammonia water, ammonium carbonate and ammonium bicarbonate; wherein, when the pH adjuster is the first pH adjuster, the initiator is the first initiator; and / or when the pH adjuster is the second pH adjuster, the initiator is the second initiator; and / or when the pH adjuster is the third pH adjuster, the initiator is the third initiator.

[0018] Furthermore, step S3 also includes the step of stirring the completed liquid of the fluorination reaction for 1 to 2 hours and then aging it for 2 to 6 hours to obtain a recovered liquid containing nickel, cobalt, manganese and lithium.

[0019] By applying the technical solution of the present invention, the treatment of the three main waste residues produced by hydrometallurgy is cleverly combined with each other. Through coordinated treatment, the problem of the waste residues produced in the hydrometallurgical recovery process being difficult to treat is solved, and the maximum possible recovery of valuable metals is achieved at a very low cost. In addition, there is no need to add special reagents such as defluorinating agents. Only simple initiators are needed to achieve the effect of simultaneous iron, aluminum and fluorine removal, strong impurity removal selectivity and good separation effect. The recovery method of the present invention can separate the impurity element substances from the valuable metal elements well, realize full element recovery, and is simple and easy to implement, more practical, and easy to realize scientific, reasonable and efficient industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 A process flow chart of hydrometallurgical recovery of lithium battery positive electrode powder is shown; and

[0022] Figure 2 A waste residue recovery process flow chart according to Example 1 of the present invention is shown. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] It should be noted that, as described in the background technology, the first metal-containing waste slag of the present invention refers to the acid leaching waste slag of lithium battery positive electrode powder, which mainly contains unleached nickel, cobalt, manganese and lithium, and also contains a large amount of binder and conductive agent; the second metal-containing waste slag refers to the iron-aluminum waste slag of lithium battery positive electrode powder, which mainly contains amorphous iron hydroxide, aluminum hydroxide and partially precipitated nickel, cobalt and manganese, as well as adsorbed lithium ions; the third metal-containing waste slag refers to the calcium-magnesium waste slag of lithium battery positive electrode powder, which mainly contains manganese nickel fluoride and calcium magnesium fluoride. Unless otherwise specified, the first metal-containing waste slag, the second metal-containing waste slag and the third metal-containing waste slag of the present invention all refer to the dry basis of waste slag.

[0025] Terminology explanation:

[0026] Liquid-to-solid ratio: the mass ratio of solution to solid material.

[0027] As described in the background of the present invention, the prior art has the problem that waste slag generated by hydrometallurgical recovery of lithium battery positive electrode powder is difficult to recycle. In order to solve the above problems, in a typical embodiment of the present invention, a method for recovering waste slag generated by wet recovery of lithium battery positive electrode powder is provided, the waste slag includes a first metal-containing waste slag, a second metal-containing waste slag and a third metal-containing waste slag, the first metal-containing waste slag contains nickel, cobalt, manganese and lithium elements; the second metal-containing waste slag contains iron, aluminum, nickel, cobalt, manganese and lithium elements; the third metal-containing waste slag contains fluorine, calcium, magnesium, nickel and manganese elements; the recovery method includes the following steps: step S1, dissolving the first metal-containing waste slag with a sulfuric acid aqueous solution, and heating and leaching to obtain a first dissolving solution; step S2, diluting the first dissolving solution with a diluent to obtain a first dissolving solution dilution solution; dissolving the second metal-containing waste slag with the first dissolving solution dilution solution to obtain a second dissolving solution; dissolving the third metal-containing waste slag with the first dissolving solution dilution solution to obtain a third dissolving solution; step S3, mixing the second dissolving solution and the third dissolving solution to obtain a mixed solution; adding an initiator to the mixed solution to adjust the pH of the mixed solution to 4.5-5.1, and triggering a fluorination reaction to obtain a nickel-cobalt-manganese-lithium recovery solution.

[0028] As described above, the first metal-containing waste slag mainly contains unleached nickel, cobalt, manganese, lithium, binder and conductive agent. According to the characteristics of the first metal-containing waste slag, the present invention first dissolves the first metal-containing waste slag with an aqueous sulfuric acid solution, and performs heating leaching, and extracts the unleached nickel, cobalt, manganese and lithium in a free state into an aqueous sulfuric acid solution at a relatively high temperature to obtain a first dissolving solution, which is mainly a sulfuric acid solution containing nickel, cobalt, manganese and lithium ions, and the binder and conductive agent with strong hydrophobicity and low density enter the filter residue for separation; then the first dissolving solution is diluted with a diluent to obtain a first dissolving solution diluent, and the first dissolving solution diluent is used to dissolve the second metal-containing waste slag, and the amorphous iron hydroxide, aluminum hydroxide and partially precipitated nickel, cobalt and manganese and adsorbed lithium ions therein are all extracted into the solution to obtain a second dissolving solution, and the second dissolving solution is mainly a solution containing iron, aluminum, nickel, cobalt, manganese and lithium ions.

[0029] Then, the third metal-containing waste slag is dissolved with the first dissolving liquid diluent, and the fluorine, nickel and manganese therein are extracted into the solution to obtain the third dissolving liquid. Since the calcium fluoride and magnesium fluoride in the third metal-containing waste slag are slightly soluble in the diluted sulfuric acid dissolving liquid, the calcium and magnesium can be separated out in the form of precipitation after the third metal-containing waste slag is completely dissolved, and only a small amount of calcium and magnesium enter the third dissolving liquid in the form of ions. The third dissolving liquid is mainly a solution containing fluorine, nickel, manganese ions or their complexes.

[0030] Finally, the second dissolving liquid and the third dissolving liquid are mixed to obtain a mixed liquid. After the two dissolving liquids are mixed with each other, the mixed liquid contains more nickel complex fluoride, manganese complex fluoride and free fluoride ions. At this time, an initiator is added to the mixed liquid to trigger the fluorination reaction, and the pH of the solution can be increased. At this time, the pH of the reaction liquid is 4.5-5.1, which is more conducive to the fluorination reaction. After the precipitation is filtered, the filtrate is a nickel-cobalt-manganese-lithium recovery liquid, and the filter residue is mainly a fluoroaluminate compound and a part of the iron hydroxide precipitate. Because fluoride ions have excellent selectivity for aluminum ions, they will not adsorb or precipitate nickel, cobalt, manganese and lithium. The fluorination reaction mainly generates fluoroaluminates, and fluoroaluminates have better crystallinity and are easier to filter. At the same time, the iron in the solution is hydrolyzed due to the increase in pH to form iron hydroxide precipitation for removal, so it can play the role of removing fluorine and iron and aluminum at the same time, with strong impurity removal selectivity and good separation effect. It is not necessary to add special reagents such as defluorinating agents, and other impurities are not introduced, so as to achieve the maximum recovery of nickel, cobalt, manganese and lithium. The aluminum content in the nickel-cobalt-manganese-lithium recovery liquid is below 30 ppm, and the fluorine content is below 50 ppm, and it can be incorporated into the subsequent hydrometallurgical leaching liquid for further recovery of nickel-cobalt-manganese-lithium.

[0031] The present invention skillfully combines the treatment of three main waste residues produced by hydrometallurgy. Through coordinated treatment, it not only solves the problem that the waste residues produced in the hydrometallurgical recovery process are difficult to treat, but also uses simple chemical methods and non-harsh chemical conditions to make the recovery method simple and easy, and realizes the maximum possible recovery of valuable metals at a very low cost, and can well separate miscellaneous elements from valuable metal elements to achieve full element recovery. The method is simple and easy to implement, more practical, and easy to realize scientific, reasonable and efficient industrial application.

[0032] In a preferred embodiment, in step S1, the mass concentration of the aqueous sulfuric acid solution is 30-50%; preferably, the mass ratio of the aqueous sulfuric acid solution to the first metal-containing waste slag is (10-20): 1. A relatively concentrated sulfuric acid solution and a large liquid-solid ratio are conducive to leaching the remaining valuable metals in the first metal waste slag, further increasing the recovery rate of valuable metals, and the leached sulfuric acid can be used in other processes.

[0033] Higher temperature can also increase the leaching rate of valuable metals. In a preferred embodiment, in step S1, the heating leaching temperature is 80-90° C. and the time is 1-3 hours.

[0034] In a preferred embodiment, in step S2, the diluent is water or a mixture of water and hydrogen peroxide, preferably a mixture of water and hydrogen peroxide. The amount of hydrogen peroxide added can be adjusted as needed. Adding a small amount of hydrogen peroxide can increase the leaching rate of nickel, cobalt and manganese, and can act as an oxidant while diluting, making it more convenient to carry out subsequent waste slag dissolution.

[0035] Specifically, in a preferred embodiment, in step S2, the volume ratio of the diluent to the first dissolving solution is (0.5-1):1. After the obtained first dissolving solution is diluted according to the above ratio, it can be more conveniently used to dissolve the second metal-containing waste slag and the third metal-containing waste slag, thereby improving the leaching rate.

[0036] In step S2, the mass ratio of the first dissolving liquid diluent to the second metal-containing waste slag and the third metal-containing waste slag can be adaptively adjusted according to the metal content in the waste slag during the actual treatment process. For the purpose of further reducing material waste and reducing costs while completely dissolving the second metal-containing waste slag and the third metal-containing waste slag, in a preferred embodiment, the pH of the second dissolving liquid is less than 1, and the pH of the third dissolving liquid is less than 2. The pH of the dissolving liquid is related to the waste slag composition and the amount of diluent added to the first dissolving liquid. Controlling the pH of the dissolving liquid within the above range can further extract all amorphous iron hydroxide, aluminum hydroxide, partially precipitated nickel, cobalt, and manganese, as well as adsorbed lithium ions in the second metal-containing waste slag into the solution, and further reduce the dissolution of calcium and magnesium in the third dissolving liquid in the solution, and the calcium and magnesium removal effect is better.

[0037] In a preferred embodiment, the second dissolving solution includes aluminum and the third dissolving solution includes fluorine. In step S3, the second dissolving solution and the third dissolving solution are mixed according to an aluminum:fluorine molar ratio of 1:(5.5-6.1), which can further reduce the aluminum impurities in the final recovered liquid to a relatively low content and achieve a better impurity removal effect.

[0038] As described above, the present application does not require the preparation of a defluorinating agent, but only requires the use of a simple initiator to achieve the effect of simultaneously removing iron, aluminum and fluorine. In order to further enhance the selectivity of the fluorination reaction and improve the separation effect, in a preferred embodiment, in step S3, the initiator includes one or more of a first initiator, a second initiator and a third initiator; wherein the first initiator includes sodium hydroxide and / or sodium carbonate, the second initiator includes potassium hydroxide and / or potassium carbonate, and the third initiator includes ammonia water and / or ammonium carbonate.

[0039] In order to avoid introducing more impurities in the recovery process, in a preferred embodiment, wet recovery uses a pH adjuster to remove iron and aluminum, and the pH adjuster includes one or more of a first pH adjuster, a second pH adjuster, and a third pH adjuster; wherein the first pH adjuster includes one or more of sodium hydroxide, sodium carbonate, and sodium bicarbonate, the second pH adjuster includes one or more of potassium hydroxide, potassium carbonate, and potassium bicarbonate, and the third pH adjuster includes one or more of ammonia water, ammonium carbonate, and ammonium bicarbonate; wherein, when the pH adjuster is the first pH adjuster, the initiator is the first initiator; and / or when the pH adjuster is the second pH adjuster, the initiator is the second initiator; and / or when the pH adjuster is the third pH adjuster, the initiator is the third initiator. The purpose of the pH adjuster and the initiator being the same metal salt is to ensure that the precipitated product obtained after the fluorination reaction is the same fluoroaluminate, and the generated product is purer, thereby achieving further separation of the heteroelement substance and the valuable metal element, and better achieving separation and recovery of all elements.

[0040] In a preferred embodiment, step S3 further includes stirring the completed solution of the fluorination reaction for 1 to 2 hours and then aging it for 2 to 6 hours to obtain a recovered solution containing nickel, cobalt, manganese and lithium. This can further promote the occurrence of the fluorination reaction, so that fluorine, iron and aluminum in the solution can be more fully removed.

[0041] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0042] Example 1

[0043] The composition of the positive electrode powder recovered in Example 1 is shown in Table 1, and the positive electrode powder hydrometallurgical recovery process flow chart is shown in Figure 1 The process flow diagram of the waste slag recovery is shown in Figure 2 .

[0044] Table 1

[0045] Element content / % nickel cobalt manganese lithium iron aluminum copper calcium magnesium Positive electrode powder 8.66 8.80 25.29 4.05 0.05 2.74 0.11 0.06 0.02

[0046] (1) Treatment of the first metal-containing waste slag: A 45% by mass aqueous sulfuric acid solution and the first metal-containing waste slag were mixed in a mass ratio of 10:1 at 85° C., stirred for 2 h, and then filtered. The filter residue was washed with an appropriate amount of water, dried, and the valuable metal content was measured. The filtrate, i.e., the first dissolving solution, was partially returned to the heating leaching process, and partially used for dissolving the second metal-containing waste slag and the third metal-containing waste slag.

[0047] (2) Treatment of the second metal-containing waste slag: adding a mixture of water and hydrogen peroxide in an amount equal to 1 to dilute the first solution, then dissolving the second metal-containing waste slag until it is completely dissolved, filtering to obtain a filtrate, i.e., a second solution, wherein the pH of the second solution is below 1, and the aluminum content of the second solution is 5.8 g / L;

[0048] (3) Treatment of the third metal-containing waste residue: adding a mixture of water and hydrogen peroxide in an amount equal to 1:1 to dilute the first solution, then dissolving the third metal-containing waste residue until it is completely dissolved, filtering to obtain a filtrate, i.e., a third solution, wherein the pH of the third solution is below 2, the fluorine content in the third solution is 2.7 g / L, and the filter residue is mainly calcium fluoride and magnesium fluoride;

[0049] (4) In the main process of hydrometallurgy, the pH adjusting agent is sodium hydroxide, and the initiator is a 10wt% sodium hydroxide aqueous solution; under stirring, the second dissolving solution and the third dissolving solution are mixed according to the aluminum:fluorine molar ratio of 1:6.02, and the initiator is added to cause a fluorination reaction. The pH of the reaction solution is 4.67, and a white precipitate is produced. After the reaction is stable, the pH remains unchanged within 2 hours, and the stirring is continued for 1 hour. After aging for 2 hours, the nickel-cobalt-manganese-lithium filtrate is filtered to obtain the nickel-cobalt-manganese-lithium filtrate, which is incorporated into the wet recovery main process leachate. The final nickel-cobalt-manganese-lithium filtrate has an aluminum content of 25 mg / L, an iron content of 28 mg / L, and a fluorine content of 34 mg / L.

[0050] The contents of valuable metals in the first metal-containing waste slag before and after leaching are shown in Table 2; the overall recovery rates of each valuable metal are shown in Table 3.

[0051] Table 2

[0052] Element content / % nickel cobalt manganese lithium Before treatment 0.70 0.61 15.04 0.86 After treatment 0.026 0.006 0.026 0.004

[0053] Table 3

[0054] project nickel cobalt manganese lithium aluminum iron Recovery rate / % 99.95 99.97 99.84 99.74 99.88 99.75

[0055] Example 2

[0056] The composition of the positive electrode powder recovered in Example 2 is shown in Table 4.

[0057] Table 4

[0058] Element content / % nickel cobalt manganese lithium iron aluminum copper calcium magnesium Positive electrode powder 26.74 10.37 14.82 5.94 0.013 1.02 1.13 0.028 0.001

[0059] In Example 2, only the first metal-containing waste residue was treated: a 35% by mass aqueous solution of sulfuric acid was mixed with the first metal-containing waste residue in a mass ratio of 15:1, stirred at 85°C for 2h and then filtered. The filter residue was washed with an appropriate amount of water, dried and its valuable metal content was measured, see Table 5.

[0060] Table 5

[0061] Element content / % nickel cobalt manganese lithium Before treatment 4.66 1.48 2.20 0.99 After treatment 0.028 0.009 0.013 0.004

[0062] Example 3

[0063] The composition of the positive electrode powder recovered in Example 3 is shown in Table 6.

[0064] Table 6

[0065] Element content / % nickel cobalt manganese lithium iron aluminum copper calcium magnesium Positive electrode powder 6.51 6.98 28.63 3.31 0.056 3.25 0.174 0.174 0.036

[0066] (1) Treatment of the first metal-containing waste slag: A 45% by mass aqueous sulfuric acid solution and the first metal-containing waste slag were mixed in a mass ratio of 10:1 at 85° C., stirred for 2 h, and then filtered. The filter residue was washed with an appropriate amount of water, dried, and the valuable metal content was measured. The filtrate, i.e., the first dissolving solution, was partially returned to the heating leaching process, and partially used for dissolving the second metal-containing waste slag and the third metal-containing waste slag.

[0067] (2) Treatment of the second metal-containing waste slag: adding a mixture of water and hydrogen peroxide in an amount equal to one time the amount of the first solution to dilute the first solution, then dissolving the second metal-containing waste slag until it is completely dissolved, filtering to obtain a filtrate, i.e., a second solution, wherein the pH of the second solution is below 1, and the aluminum content in the second solution is 6.4 g / L;

[0068] (3) Treatment of the third metal-containing waste residue: adding a mixture of water and hydrogen peroxide in an amount equal to 1:1 to dilute the first solution, then dissolving the third metal-containing waste residue until it is completely dissolved, filtering to obtain a filtrate, i.e., a third solution, wherein the pH of the third solution is below 2, the fluorine content in the third solution is 4.9 g / L, and the filter residue is mainly calcium fluoride and magnesium fluoride;

[0069] (4) In the main process of hydrometallurgy, the pH adjusting agent is potassium carbonate, and the initiator is a 15wt% potassium carbonate aqueous solution; under stirring, the second dissolving solution and the third dissolving solution are mixed according to the aluminum:fluorine molar ratio of 1:5.8, and the initiator is added to cause a fluorination reaction. The pH of the reaction solution is 4.87, and a white precipitate is produced. After the reaction is stable, the pH remains unchanged within 2 hours, and the stirring is continued for 1 hour. After aging for 3 hours, the nickel-cobalt-manganese-lithium filtrate is filtered to obtain the nickel-cobalt-manganese-lithium filtrate, which is incorporated into the wet recovery main process leachate. The aluminum content of the final nickel-cobalt-manganese-lithium filtrate is 18 mg / L, the iron content is 13 mg / L, and the fluorine content is 44 mg / L. The overall recovery rate of each valuable metal is shown in Table 7.

[0070] Table 7

[0071] project nickel cobalt manganese lithium aluminum iron Recovery rate / % 99.89 99.93 99.89 99.84 99.79 99.85

[0072] Example 4

[0073] The composition of the positive electrode powder recovered in Example 4 is shown in Table 8.

[0074] Table 8

[0075] Element content / % nickel cobalt manganese lithium iron aluminum copper calcium magnesium Positive electrode powder 13.45 11.64 16.37 4.89 0.021 2.17 0.11 0.036 0.009

[0076] (1) Treatment of the first metal-containing waste slag: a 35% by mass sulfuric acid solution and the first metal-containing waste slag were mixed in a mass ratio of 10:1 at 85° C., stirred for 2 h, and then filtered. The filter residue was washed with an appropriate amount of water, dried, and the valuable metal content was measured. The filtrate, i.e., the first dissolving solution, was partially returned to the heating leaching process, and partially used for dissolving the second metal-containing waste slag and the third metal-containing waste slag.

[0077] (2) Treatment of the second metal-containing waste slag: adding 0.5 times the amount of a mixture of water and hydrogen peroxide to dilute the first solution, then dissolving the second metal-containing waste slag until it is completely dissolved, filtering to obtain a filtrate, i.e., a second solution, wherein the pH of the second solution is below 1, and the aluminum content in the second solution is 3.7 g / L;

[0078] (3) Treatment of the third metal-containing waste slag: adding 0.5 times the amount of a mixture of water and hydrogen peroxide to dilute the first dissolving solution, then dissolving the third metal-containing waste slag until it is completely dissolved, filtering to obtain a filtrate, i.e., a third dissolving solution, wherein the pH value of the third dissolving solution is below 2, the fluorine content in the third dissolving solution is 3.2 g / L, and the filter residue is mainly calcium fluoride and magnesium fluoride;

[0079] (4) In the main process of hydrometallurgy, the pH adjusting agent is ammonia water, and the initiator is 10wt% ammonia water; under stirring, the second dissolving solution and the third dissolving solution are mixed according to the aluminum:fluorine molar ratio of 1:5.6, and the initiator is added to cause a fluorination reaction, and the pH of the reaction solution is adjusted to 4.54 to produce a white precipitate. After the reaction is stable, the pH remains unchanged within 2 hours, and the stirring is continued for 1 hour. After aging for 5 hours, the nickel-cobalt-manganese-lithium filtrate is filtered to obtain the nickel-cobalt-manganese-lithium filtrate, which is incorporated into the wet recovery leachate. The aluminum content of the final nickel-cobalt-manganese-lithium filtrate is 13 mg / L, the iron content is 24 mg / L, and the fluorine content is 14 mg / L. The overall recovery rate of each valuable metal is shown in Table 9.

[0080] Table 9

[0081] project nickel cobalt manganese lithium aluminum iron Recovery rate / % 99.79 99.86 99.91 99.76 99.90 99.73

[0082] Example 5

[0083] The composition of the positive electrode powder recovered in Example 5 is the same as that in Example 1.

[0084] (1) Treatment of the first metal-containing waste slag: A 30% by mass aqueous sulfuric acid solution and the first metal-containing waste slag were mixed in a mass ratio of 20:1 at 80° C., stirred for 3 h, and then filtered. The filter residue was washed with an appropriate amount of water, dried, and the valuable metal content was measured. The filtrate, i.e., the first dissolving solution, was partially returned to the heating leaching step, and partially used for dissolving the second metal-containing waste slag and the third metal-containing waste slag.

[0085] (2) Treatment of the second metal-containing waste slag: adding a mixture of water and hydrogen peroxide in an amount equal to 1 to dilute the first solution, then dissolving the second metal-containing waste slag until it is completely dissolved, filtering to obtain a filtrate, i.e., a second solution, wherein the pH of the second solution is below 1, and the aluminum content of the second solution is 5.8 g / L;

[0086] (3) Treatment of the third metal-containing waste residue: adding a mixture of water and hydrogen peroxide in an amount equal to 1:1 to dilute the first solution, then dissolving the third metal-containing waste residue until it is completely dissolved, filtering to obtain a filtrate, i.e., a third solution, wherein the pH of the third solution is below 2, the fluorine content in the third solution is 2.7 g / L, and the filter residue is mainly calcium fluoride and magnesium fluoride;

[0087] (4) In the main process of hydrometallurgy, the pH adjusting agent is sodium hydroxide, and the initiator is a 10wt% sodium hydroxide aqueous solution; under stirring, the second dissolving solution and the third dissolving solution are mixed according to the aluminum:fluorine molar ratio of 1:5.5, and the initiator is added to cause a fluorination reaction. The pH of the reaction solution is 4.5, and a white precipitate is generated. After the reaction is stable, the pH remains unchanged within 2 hours, and the stirring is continued for 1 hour. After aging for 2 hours, the nickel-cobalt-manganese-lithium filtrate is filtered to obtain the nickel-cobalt-manganese-lithium filtrate, which is incorporated into the wet recovery main process leachate. The final nickel-cobalt-manganese-lithium filtrate has an aluminum content of 27 mg / L, an iron content of 30 mg / L, and a fluorine content of 15 mg / L.

[0088] The contents of valuable metals in the first metal-containing waste slag before and after leaching are shown in Table 10; the overall recovery rates of each valuable metal are shown in Table 11.

[0089] Table 10

[0090] Element content / % nickel cobalt manganese lithium Before treatment 0.70 0.61 15.04 0.86 After treatment 0.029 0.008 0.028 0.026

[0091] Table 11

[0092] project nickel cobalt manganese lithium aluminum iron Recovery rate / % 99.92 99.95 99.83 99.71 99.85 99.73

[0093] Example 6

[0094] The composition of the positive electrode powder recovered in Example 6 is the same as that in Example 1.

[0095] (1) Treatment of the first metal-containing waste slag: A 50% by mass aqueous solution of sulfuric acid and the first metal-containing waste slag are mixed in a mass ratio of 10:1 at 90° C., stirred for 1 hour, and then filtered. The filter residue is washed with an appropriate amount of water, dried, and the content of valuable metals is measured; the filtrate is the first dissolving solution, part of which is returned to the heating leaching process, and part of which is used for dissolving the second metal-containing waste slag and the third metal-containing waste slag;

[0096] (2) Treatment of the second metal-containing waste slag: adding a mixture of water and hydrogen peroxide in an amount equal to 1 to dilute the first solution, then dissolving the second metal-containing waste slag until it is completely dissolved, filtering to obtain a filtrate, i.e., a second solution, wherein the pH of the second solution is below 1, and the aluminum content of the second solution is 5.8 g / L;

[0097] (3) Treatment of the third metal-containing waste residue: adding a mixture of water and hydrogen peroxide in an amount equal to 1:1 to dilute the first solution, then dissolving the third metal-containing waste residue until it is completely dissolved, filtering to obtain a filtrate, i.e., a third solution, wherein the pH of the third solution is below 2, the fluorine content in the third solution is 2.7 g / L, and the filter residue is mainly calcium fluoride and magnesium fluoride;

[0098] (4) In the main process of hydrometallurgy, the pH adjusting agent is sodium hydroxide, and the initiator is a 10wt% sodium hydroxide aqueous solution; under stirring, the second dissolving solution and the third dissolving solution are mixed according to the aluminum:fluorine molar ratio of 1:6.1, and the initiator is added to cause a fluorination reaction. The pH of the reaction solution is 5.1, and a white precipitate is produced. After the reaction is stable, the pH remains unchanged within 2 hours, and the stirring is continued for 2 hours. After aging for 6 hours, the nickel-cobalt-manganese-lithium filtrate is filtered to obtain the nickel-cobalt-manganese-lithium filtrate, which is incorporated into the wet recovery main process leachate. The final nickel-cobalt-manganese-lithium filtrate has an aluminum content of 28 mg / L, an iron content of 29 mg / L, and a fluorine content of 36 mg / L.

[0099] The contents of valuable metals in the first metal-containing waste slag before and after leaching are shown in Table 12; the overall recovery rates of each valuable metal are shown in Table 13.

[0100] Table 12

[0101] Element content / % nickel cobalt manganese lithium Before treatment 0.70 0.61 15.04 0.86 After treatment 0.028 0.009 0.030 0.027

[0102] Table 13

[0103] project nickel cobalt manganese lithium aluminum iron Recovery rate / % 99.91 99.94 99.84 99.70 99.84 99.75

[0104] Comparative Example 1

[0105] The second metal-containing waste residue in Example 1 was treated with 80 g / L sodium hydroxide aqueous solution, with a liquid-to-solid ratio of 10, and the temperature of the mixture was controlled to be 90°C. After reacting for 3 hours, the mixture was filtered and the residue was tested by ICP-AES. The dissolution rate of aluminum element was only 74.43%, which was converted into a lithium solubility of 54.3% in the filtrate. Nickel, cobalt, manganese and iron were all in the residue, and the undissolved lithium was adsorbed on the surface of the residue.

[0106] As can be seen from the above, compared with the comparative example, the embodiments of the present invention skillfully combine the treatment of the three main waste residues produced by hydrometallurgy with each other, and through coordinated treatment, not only solve the problem that the waste residues produced in the hydrometallurgical recovery process are difficult to handle, but also achieve the maximum possible recovery of valuable metals at a very low cost. In addition, there is no need to add special reagents such as defluorinating agents, and only a simple initiator is needed to achieve the effect of simultaneous iron removal, aluminum and fluorine removal, strong impurity removal selectivity, good separation effect, and can make the impurity element substances and valuable metal elements well separated, realize full element recovery, and simple and easy, more in line with reality. In addition, it can be seen that when the recovery process parameters are all within the preferred range of the present invention, the impurity removal effect and the recovery rate of valuable metals are better.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for recovering waste residue generated by wet recovery of lithium battery positive electrode powder, wherein the waste residue comprises a first metal-containing waste residue, a second metal-containing waste residue and a third metal-containing waste residue, wherein the first metal-containing waste residue is a lithium battery positive electrode powder acid leaching waste residue, comprising unleached nickel, cobalt, manganese and lithium, a binder and a conductive agent; the second metal-containing waste residue is a lithium battery positive electrode powder leachate iron-aluminum-free waste residue, comprising amorphous iron hydroxide, aluminum hydroxide and partially precipitated nickel, cobalt and manganese and adsorbed lithium ions; the third metal-containing waste residue is a lithium battery positive electrode powder leachate calcium-magnesium-free waste residue, comprising nickel manganese fluoride and calcium and magnesium fluoride; characterized in that The recovery method comprises the following steps: Step S1, dissolving the first metal-containing waste slag with a sulfuric acid aqueous solution, and heating and leaching to obtain a first dissolved solution; Step S2, diluting the first dissolving solution with a diluent to obtain a first dissolving solution dilution solution; dissolving the second metal-containing waste slag with the first dissolving solution dilution solution to obtain a second dissolving solution; dissolving the third metal-containing waste slag with the first dissolving solution dilution solution to obtain a third dissolving solution; Step S3, mixing the second dissolving solution and the third dissolving solution to obtain a mixed solution; adding an initiator to the mixed solution to adjust the pH of the mixed solution to 4.5-5.1, and triggering a fluorination reaction to obtain a nickel-cobalt-manganese-lithium recovery solution; Wherein, the diluent is water, or a mixture of water and hydrogen peroxide; the initiator includes one or more of a first initiator, a second initiator and a third initiator, the first initiator includes sodium hydroxide and / or sodium carbonate, the second initiator includes potassium hydroxide and / or potassium carbonate, and the third initiator includes ammonia water and / or ammonium carbonate.

2. The recycling method according to claim 1, characterized in that: In step S1, the mass concentration of the aqueous sulfuric acid solution is 30-50%.

3. The recovery method according to claim 1 or 2, characterized in that: In the step S1, the mass ratio of the aqueous sulfuric acid solution to the first metal-containing waste slag is (10-20):

1.

4. The recycling method according to claim 1 or 2, characterized in that: In the step S1, the heating leaching temperature is 80-90° C. and the time is 1-3 hours.

5. The recycling method according to claim 1 or 2, characterized in that: In the step S2, the volume ratio of the diluent to the first dissolving solution is (0.5~1):

1.

6. The recycling method according to claim 1 or 2, characterized in that: In step S2, the pH of the second dissolving solution is less than 1, and the pH of the third dissolving solution is less than 2.

7. The recycling method according to claim 1 or 2, characterized in that: The second dissolving solution includes aluminum, and the third dissolving solution includes fluorine. In the step S3, the second dissolving solution and the third dissolving solution are mixed according to a molar ratio of aluminum to fluorine of 1:(5.5-6.1).

8. The recycling method according to claim 1, characterized in that: The wet recovery uses a pH regulator to remove iron and aluminum, and the pH regulator includes one or more of a first pH regulator, a second pH regulator, and a third pH regulator; wherein the first pH regulator includes one or more of sodium hydroxide, sodium carbonate, and sodium bicarbonate, the second pH regulator includes one or more of potassium hydroxide, potassium carbonate, and potassium bicarbonate, and the third pH regulator includes one or more of ammonia water, ammonium carbonate, and ammonium bicarbonate; Among them, when the pH adjuster is the first pH adjuster, the initiator is the first initiator; and / or when the pH adjuster is the second pH adjuster, the initiator is the second initiator; and / or when the pH adjuster is the third pH adjuster, the initiator is the third initiator.

9. The recycling method according to claim 1 or 2, characterized in that: The step S3 also includes the step of stirring the completed solution of the fluorination reaction for 1 to 2 hours and then aging it for 2 to 6 hours to obtain the nickel-cobalt-manganese-lithium-containing recovery solution.

Images