A combined regeneration method for waste batteries

Abstract

The present application discloses a combined regeneration treatment method for waste batteries, which comprises mixing a first manganese source obtained by pretreatment of a zinc-manganese battery, a second manganese source obtained by pretreatment of a lithium-manganese dioxide battery, and a lithium iron phosphate battery powder obtained by pretreatment of a lithium iron phosphate battery to obtain a mixed waste material, adding an inorganic acid solution to the mixed waste material, performing acidification roasting or acid leaching treatment, and then mixing the mixed waste material with a lithium-containing solution obtained by pretreatment of the lithium-manganese dioxide battery, adjusting the pH value of the mixed slurry, and performing a dephosphorization treatment to obtain iron phosphate slag and a lithium-manganese mixed salt solution; extracting and separating the lithium-manganese mixed salt solution to obtain a manganese salt solution and a lithium salt solution; compared with the prior art, the present application makes full use of the reducibility of lithium iron phosphate and the oxidizability of the manganese source, performs redox reaction in an acidic environment, can save the reducing agent and oxidizing agent required for recovery, and reduces the regeneration cost of waste batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of waste battery recycling and treatment, and in particular to a method for combined recycling and treatment of waste lithium iron phosphate batteries and waste batteries in mandatory classification of domestic waste. Background Art

[0002] At present, there are two general methods for the treatment of used batteries in the world: (1) solidification and deep burial. This treatment method is not only expensive and has the potential for pollution, but also prone to waste. After all, there are still many useful substances in used batteries that can be used as raw materials; (2) recycling. The harmless treatment and recycling of used batteries are of great significance to protecting the environment and saving resources, and are the preferred methods for the treatment of used batteries.

[0003] From a technical point of view, any type of waste battery can be recycled, but the current commercial waste battery recycling projects are basically for lead-acid batteries and batteries with high cobalt and nickel content. Other types of waste batteries have not been commercially recycled because of their small quantity and scattered locations, or because the economic value of recycling is too low. Taking the recycling of lithium iron phosphate batteries as an example, the "China Retired Power Battery Recycling Technology and Industrial Development Report" released by the Chinese Academy of Sciences in 2019 pointed out that the cost of recycling 1 ton of scrapped lithium iron phosphate batteries is about 8,500 yuan, and the output of lithium carbonate, graphite, copper, aluminum and other materials is worth about 8,100 yuan, with a loss of 4,000 yuan per ton.

[0004] In addition, although garbage classification has not been fully implemented in China so far, mandatory classification of domestic waste is in full swing in key cities. For example, Shanghai officially implemented garbage classification on July 1, 2019, and Shenzhen also officially implemented the "Shenzhen Domestic Waste Classification Management Regulations" on May 1, 2020. In principle, the classification and treatment of domestic waste is conducive to environmental protection and the recycling of resources, but how to deal with classified waste is still a difficult problem that needs to be solved urgently, especially the waste batteries in hazardous waste.

[0005] Common waste batteries involved in the classification of domestic waste are generally zinc-manganese batteries (including carbon batteries and alkaline batteries, of which alkaline batteries are far more than carbon batteries), as well as some lithium batteries (including lithium-manganese dioxide batteries, various lithium-ion batteries) and nickel batteries (including nickel-hydrogen batteries, nickel-cadmium batteries), etc., which are characterized by various types and relatively small size. When recycling waste batteries from hazardous waste, compared with the losses involved in the economic benefits of lithium iron phosphate power battery regeneration, the output value is far from covering the recycling and processing costs; therefore, the current recycling and processing processes for waste batteries classified from domestic waste are basically still in the laboratory stage, with poor benefits and difficult to industrialize.

[0006] In view of this, it is necessary to provide a low-cost combined regeneration method for low-value waste batteries such as lithium iron phosphate batteries, zinc-manganese batteries and lithium-manganese dioxide batteries, so that the output value can cover the cost to promote its industrialization. Summary of the invention

[0007] In view of the deficiencies of the above-mentioned prior art, the main purpose of the present invention is to provide a combined regeneration treatment method for waste lithium iron phosphate batteries and waste batteries in the mandatory classification of domestic waste (specifically including zinc-manganese batteries and lithium-manganese dioxide batteries), aiming to solve the existing problems of high cost, poor economic benefits and non-industrialization of these waste battery treatments, improve resource utilization, reduce environmental pressure, and provide more industrial treatment methods for the mandatory classification of domestic waste.

[0008] A combined regeneration method for waste batteries, comprising: pre-treating a recovered zinc-manganese battery to obtain a first potassium-containing alkali solution, a zinc-containing solution and a first manganese source, pre-treating a recovered lithium-manganese dioxide battery to obtain a lithium-containing solution and a second manganese source, and pre-treating a recovered lithium iron phosphate battery to obtain lithium iron phosphate battery powder; mixing the first manganese source and / or the second manganese source with the lithium iron phosphate battery powder to obtain a mixed waste, wherein the content of trivalent manganese in the first manganese source and / or the second manganese source is M moles, and the content of tetravalent manganese is N moles. The content of lithium iron phosphate in the lithium iron phosphate battery powder is T moles, M+2N=(0.8~1.2)T; add an inorganic acid solution to the mixed waste, acidify and roast, then add water to mix or directly acid-leach to obtain a mixed slurry; dissolve an alkaline regulator in a lithium-containing solution to obtain a lithium-containing alkali solution, use the lithium-containing alkali solution to adjust the pH value of the mixed slurry to 3.5-6.0 for dephosphorization treatment, and obtain iron phosphate slag and a lithium-manganese mixed salt solution; extract and separate the lithium-manganese mixed salt solution to obtain a manganese salt solution and a lithium salt solution. Specifically, the pretreatment of the recovered zinc-manganese battery to obtain a first potassium-containing alkali solution, a zinc-containing solution and a first manganese source includes: crushing, drying and sorting the recovered zinc-manganese battery in sequence to obtain zinc-manganese battery powder; washing the zinc-manganese battery powder to obtain a first potassium-containing alkali solution and washed slag; acid-leaching the washed slag to obtain a zinc-containing solution and a first manganese source.

[0009] Furthermore, the pretreatment of the recovered lithium-manganese dioxide battery to obtain a lithium-containing solution and a second manganese source, and the pretreatment of the recovered lithium iron phosphate battery to obtain lithium iron phosphate battery powder, also includes: collecting the first fluorine-containing waste gas generated in the pretreatment of the recovered lithium-manganese dioxide battery and the second fluorine-containing waste gas generated in the pretreatment of the recovered lithium iron phosphate battery; performing secondary combustion treatment on the first fluorine-containing waste gas and the second fluorine-containing waste gas to obtain a first waste gas; and spraying the first waste gas with the first potassium-containing alkali solution to obtain a fluorine-containing waste liquid and a third waste gas.

[0010] Furthermore, lime powder is added to the fluorine-containing waste liquid, and filtered to obtain filter residue and mixed alkali solution; the mixed alkali solution is decalcified to obtain calcium carbonate and a second potassium-containing alkali solution.

[0011] Furthermore, the method further comprises: purifying the zinc-containing solution and then electrolyzing it to obtain electrolytic metallic zinc and an acid solution; wherein the purification treatment comprises one or more of oxidation precipitation, complex salt precipitation or zinc powder replacement.

[0012] Furthermore, the acid solution can also be used to carry out acid leaching treatment on the water-washed slag.

[0013] Specifically, the treatment agent used in the decalcification treatment of the mixed alkali solution includes at least one of carbon dioxide, potassium carbonate, and sodium carbonate; the extractant used in the extraction and separation treatment includes one or two of P204 and P507; the inorganic acid solution is at least one of sulfuric acid solution, hydrochloric acid solution and nitric acid solution; the alkaline regulator is at least one of sodium hydroxide, sodium carbonate, potassium hydroxide and potassium carbonate.

[0014] Compared with the prior art, the combined treatment method for waste batteries proposed in the present application has the following advantages: pre-treating the recovered zinc-manganese battery to obtain a first potassium-containing alkaline solution, a zinc-containing solution and a first manganese source, pre-treating the recovered lithium-manganese dioxide battery to obtain a lithium-containing solution and a second manganese source, and pre-treating the recovered lithium iron phosphate battery to obtain lithium iron phosphate battery powder; mixing the first manganese source and / or the second manganese source with the lithium iron phosphate battery powder to obtain a mixed waste; adding an inorganic acid solution to the mixed waste, acidifying and roasting, and then adding water to mix or directly acid leaching to obtain a mixed slurry; dissolving an alkaline regulator in the lithium-containing solution to obtain a lithium-containing alkaline solution, adjusting the pH value of the mixed slurry to 3.5-6.0 with the lithium-containing alkaline solution for dephosphorization treatment, and obtaining iron phosphate slag and a lithium-manganese mixed salt solution; extracting and separating the lithium-manganese mixed salt solution to obtain a manganese salt solution and a lithium salt solution. Compared with the separate recovery of manganese in zinc-manganese batteries and lithium-manganese dioxide batteries, which requires reduction roasting or leaching with a reducing agent under acidic conditions, and the separate recovery of lithium in lithium iron phosphate batteries, which requires oxidation roasting or leaching with an oxidant under acidic conditions, the combined regeneration process fully utilizes the reducibility of lithium iron phosphate in lithium iron phosphate batteries and the oxidizability of trivalent manganese and tetravalent manganese in zinc-manganese batteries and lithium-manganese dioxide batteries, and performs redox reactions in an acidic environment, saving the reductant required for manganese recovery and the oxidant required for lithium recovery, which can reduce the recycling costs of zinc-manganese batteries, lithium-manganese dioxide batteries and lithium iron phosphate batteries, expand the scope of the combined regeneration process, and even make the recycling of lithium iron phosphate batteries profitable. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1It is a schematic diagram of the combined regeneration method for waste batteries of the present invention;

[0016] Figure 2 This is a flow chart of the combined regeneration method for waste batteries of the present invention;

[0017] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0018] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0019] The waste batteries involved in this application are generally used batteries, including zinc-manganese batteries, lithium-manganese dioxide batteries, and lithium iron phosphate batteries. The specific conditions of the above batteries will be described in detail in the following text.

[0020] The zinc-manganese battery here includes alkaline batteries and carbon batteries. Among them, alkaline batteries are the best performing varieties in the zinc-manganese battery series. They are primary batteries with zinc as the negative electrode, manganese dioxide as the positive electrode, and potassium hydroxide solution as the electrolyte. The electrode reaction formula generally includes:

[0021] Zn+2MnO 2 + H 2 O=ZnO+2MnOOH

[0022] Zn+MnO 2 +H 2 O= ZnO+ Mn (OH) 2

[0023] It has lower internal resistance and generates more current than ordinary carbon batteries, making it suitable for applications that require large discharge capacity and long-term use.

[0024] Carbon battery is called neutral zinc-manganese dioxide dry battery (zinc-manganese dry battery), which belongs to the primary battery in chemical power source, with manganese dioxide and graphite rod as positive electrode, zinc as negative electrode, ammonium chloride, zinc chloride and starch paste as electrolyte, and the electrode reaction formula is generally:

[0025] 2Zn+2MnO 2 +2NH 4 + =2Zn 2+ + Mn 2 O 3 +2 NH 3 + H 2 O

[0026] Because its electrolyte is a non-flowing paste, it is also called a dry cell compared to a battery with a flowable electrolyte.

[0027] The lithium-manganese dioxide battery uses metallic lithium as the negative electrode and properly heat-treated manganese dioxide as the positive electrode. The electrolyte is composed of lithium perchlorate (or lithium trifluoromethanesulfonate) dissolved in a mixed solvent such as propylene carbonate / ethylene glycol dimethyl ether. It is a lithium primary battery with a large production volume. The electrode reaction formula is generally:

[0028] Li+MnO 2 =LiMnO 2

[0029] Lithium-manganese dioxide batteries have good low-rate and medium-rate discharge performance, are cheap, have good safety performance, and are competitive with conventional batteries.

[0030] Lithium iron phosphate battery is a lithium-ion battery that uses lithium iron phosphate as the positive electrode material. During charging, some lithium ions in lithium iron phosphate are released and transferred to the negative electrode through the electrolyte. At the same time, the positive electrode releases electrons and reaches the negative electrode from the external circuit to maintain the balance of the chemical reaction; during discharge, lithium ions are released from the negative electrode and reach the positive electrode through the electrolyte. At the same time, the negative electrode releases electrons and reaches the positive electrode from the external circuit to provide energy to the outside world. Lithium-ion batteries themselves are a chemical substance, so battery pollution after scrapping is inevitable, and large-scale centralized landfill will exceed the environmental tolerance.

[0031] In general, the waste batteries involved in this application are generally considered to be non-toxic and directly degradable in nature under standard production, but these batteries themselves involve chemical substances, and their degradation puts great pressure on the surrounding environment, especially after the implementation of household waste classification in cities, involving separate recycling, a large number of waste batteries are concentrated, involving different reactions between the batteries themselves, between batteries of the same type, and between batteries of different types. Even if they are non-toxic and degradable, they will pose a great safety hazard to the surrounding environment and are not suitable for direct landfill or direct storage for degradation. Based on this, this application considers the recycling of waste batteries recovered after household waste classification, solves the safety hazards after the centralized recycling of waste batteries, and also minimizes damage to the environment.

[0032] It should be noted that the problem with the existing methods for recycling and treating waste batteries is that the current recycling and regeneration of waste batteries is basically concentrated on lead-acid batteries and batteries with relatively high cobalt and / or nickel content. Both battery manufacturers and battery intermediate manufacturers (such as electric vehicle manufacturers) will track the use of lead-acid batteries and batteries with relatively high cobalt and / or nickel content during their validity period for product safety reasons, judge and estimate the recycling time and cost, so that they can be processed in batches during recycling and regeneration. Moreover, the lead, nickel, cobalt, fluoride and other harmful substances contained in these batteries must be recycled and treated according to administrative regulations. The main reason for recycling is to recycle lead, nickel, cobalt, fluoride and other substances to prevent environmental pollution, and the goal is relatively clear. Furthermore, nickel and cobalt themselves have high value, and their recycling can ensure that the recycling manufacturers benefit. Therefore, a large amount of waste battery recycling focuses on studying how to recycle nickel, cobalt, lead and other battery materials in batteries that are relatively high in price or must be recycled according to administrative regulations. However, there is little research on the recycling of zinc-manganese batteries and lithium-manganese dioxide batteries in domestic waste batteries because there are no mandatory administrative recycling regulations, the recycling costs are high, and the economic benefits of recycling are low.

[0033] Based on the above reasons, this application proposes a method for combined recycling of waste batteries, such as Figure 1 As shown, the following steps are included: S101, pre-treating the recovered zinc-manganese battery to obtain a first potassium-containing alkali solution, a zinc-containing solution and a first manganese source, pre-treating the recovered lithium-manganese dioxide battery to obtain a lithium-containing solution and a second manganese source, and pre-treating the recovered lithium iron phosphate battery to obtain lithium iron phosphate battery powder.

[0034] Different from the recycling of power batteries, the types of used batteries recycled in this application are more diverse and smaller in size. They need to be sorted first to separate different types of batteries to facilitate different pretreatments for different types of batteries. Figure 2As shown, the recycled and sorted zinc-manganese batteries are pre-treated, and the pre-treatment here includes disassembling the recycled and sorted zinc-manganese batteries and performing crushing, drying and sorting processes in sequence. Specifically, when the recycled zinc-manganese batteries are dried, the main purpose is to remove moisture. At the same time, the electrolyte will react during the drying process to produce a small amount of second waste gas. The harmful substances (such as macromolecular substances, etc.) carried in the second waste gas need to be treated before they can be directly discharged into the air. This application uses activated carbon and acidic solution to adsorb harmful substances to reduce or eliminate the content of harmful substances in the second waste gas, so that the second waste gas can be directly discharged into the atmosphere after meeting the standards; the zinc-manganese battery after crushing and drying is a mixture of zinc-manganese battery powder and iron sheet (battery packaging), etc. The battery powder and iron sheet are separated by sorting, and the packaging materials such as iron sheet are recycled separately, while the zinc-manganese battery powder is used for subsequent regeneration of manganese, zinc, etc. The main components of the zinc-manganese battery powder in the present application include metallic zinc, manganese dioxide, manganese trioxide, potassium hydroxide, potassium chloride and zinc oxide, etc. The zinc-manganese battery powder is washed with water to remove the water-soluble substances therein, including potassium hydroxide, potassium chloride, etc., to obtain a mixture of metallic zinc, zinc oxide, manganese dioxide and manganese trioxide, etc. that are insoluble in water, i.e., water-washed slag, wherein the potassium hydroxide and potassium chloride dissolved in water form the first potassium-containing alkali solution. An inorganic acid solution is added to the water-washed slag, i.e., a mixture of metallic zinc, zinc oxide, manganese dioxide and manganese trioxide, etc. that are insoluble in water, so that, for example, metallic zinc and zinc oxide are dissolved in the inorganic acid solution, and the zinc therein is completely replaced in the inorganic acid solution, while manganese dioxide and manganese trioxide, etc., cannot react with the inorganic acid and are insoluble in the inorganic acid, and then the substances soluble in the inorganic acid, such as metallic zinc and zinc oxide, and the substances insoluble in the inorganic acid, such as manganese dioxide and manganese trioxide, can be separated by filtration to obtain a zinc-containing solution and a first manganese source. Of course, a filter press method can also be used here to separate the zinc soluble in the inorganic acid from the manganese dioxide and manganese trioxide insoluble in the inorganic acid to obtain the zinc-containing solution and the first manganese source.

[0035] When recycling and sorting lithium-manganese dioxide batteries, Figure 2As shown, it also needs to be disassembled and crushed. Since the electrolyte of the lithium-manganese dioxide battery is composed of lithium perchlorate (or lithium trifluoromethanesulfonate) dissolved in a mixed solvent such as propylene carbonate / ethylene glycol dimethyl ether, after the crushing treatment, the organic mixed solvent in the electrolyte needs to be removed to reduce interference with subsequent recovery. In this application, the organic mixed solvent in the lithium-manganese dioxide battery after disassembly is removed by pyrolysis. It should be noted that during the pyrolysis treatment, a large amount of first fluorine-containing waste gas will be generated, which cannot be directly discharged into the air. The first fluorine-containing waste gas needs to be subjected to secondary combustion treatment, and then the fluorine therein is solidified. The solidification of fluorine after the secondary combustion treatment will be further explained later. After the lithium-manganese dioxide battery is subjected to pyrolysis treatment, it can be sorted, specifically by magnetic separation, to recover the iron sheet, nickel mesh and other materials therein, and obtain lithium-manganese dioxide battery powder at the same time, and then carry out subsequent recovery treatment of lithium, manganese, etc. The main components of lithium-manganese dioxide battery powder include manganese dioxide, lithium manganese oxide (LiMnO 2 ), lithium, lithium hydroxide, lithium carbonate, lithium chloride, lithium sulfate, etc., and the water-soluble lithium, lithium hydroxide, lithium carbonate, lithium chloride and lithium sulfate are separated from the water-insoluble manganese dioxide and lithium manganate by water washing, so as to obtain a lithium-containing solution: a mixed solution of water-soluble lithium hydroxide, lithium carbonate, lithium chloride and lithium sulfate, and a second manganese source: water-insoluble manganese dioxide and lithium manganate (LiMnO 2 ).

[0036] like Figure 2 As shown, the recycled lithium iron phosphate battery also needs to be crushed and disassembled during pretreatment. Considering its electrolyte, which is composed of materials such as lithium hexafluorophosphate dissolved in an organic mixed solvent, similar to the electrolyte of lithium-manganese dioxide battery, it is necessary to pyrolyze the disassembled lithium iron phosphate battery after crushing. Its electrolyte will also produce fluorine-containing waste gas during pyrolysis, that is, the second fluorine-containing waste gas, which needs to be secondary burned and then solidified to solidify the fluorine and phosphorus. After the pyrolysis treatment of the lithium iron phosphate battery, it is also sorted to recover the shell material, etc., and the pyrolyzed lithium iron phosphate battery powder is subsequently processed for iron and lithium recovery.

[0037] S102, taking the first manganese source and / or the second manganese source and mixing them with lithium iron phosphate battery powder to obtain mixed waste.

[0038] Specifically, the contents of trivalent manganese and tetravalent manganese in the first manganese source, the contents of trivalent manganese and tetravalent manganese in the second manganese source, and the content of lithium iron phosphate in the lithium iron phosphate battery powder are first detected, wherein the manganese content in the manganese source is determined by commonly used methods in the art, such as rapid titration, photometry, chemical analysis, etc.; the content of lithium iron phosphate in the lithium iron phosphate battery powder is also determined by commonly used methods in the industry, such as chemical analysis, etc., which are not elaborated in this application, and it is sufficient to select the currently commonly used determination method to measure the content.

[0039] Furthermore, the contents of trivalent manganese and tetravalent manganese in the first manganese source were measured, wherein the content of trivalent manganese in the first manganese source was M1 mole, and the content of tetravalent manganese was N1 mole; the contents of trivalent manganese and tetravalent manganese in the second manganese source were measured, wherein the mole of trivalent manganese was M2 content, and the content of tetravalent manganese was N2 mole; the content of lithium iron phosphate in the lithium iron phosphate battery powder was measured, wherein the content of lithium iron phosphate was T mole.

[0040] It should be noted that the content of trivalent manganese in the first manganese source and / or the second manganese source is M moles, the content of tetravalent manganese is N moles, and the content of lithium iron phosphate in the lithium iron phosphate battery powder is T moles, M+2N=(0.8~1.2)T. Generally, considering the specific industrial environment, the content of lithium iron phosphate in the lithium iron phosphate battery powder will be higher, that is, M+2N=(0.8~1)T. When it is insufficient, it can also participate in the reaction by directly adding waste lithium iron phosphate battery powder. Specifically, mixing the first manganese source and / or the second manganese source with the lithium iron phosphate battery powder involves three situations: mixing the first manganese source with the lithium iron phosphate battery powder, mixing the second manganese source with the lithium iron phosphate battery powder, or mixing the first manganese source, the second manganese source and the lithium iron phosphate battery powder. There are three ratios here. When the first manganese source is mixed with lithium iron phosphate battery, M=M1, N=N1, that is, M1+2N1=(0.8~1.2)T; when the second manganese source is mixed with lithium iron phosphate battery, M=M2, N=N2, that is, M2+2N2=(0.8~1.2)T; when the first manganese source and the second manganese source are mixed with lithium iron phosphate battery, M=M1+M2, N=N1+N2, that is, M1+M2+2(N1+N2)=(0.8~1.2)T. The above ratios are based on the fact that after the inorganic acid solution is added to the mixed waste, sufficient redox reaction can be carried out during acid roasting or acid leaching.

[0041] S103, adding an inorganic acid solution to the mixed waste, performing acidification and roasting, and then adding water to mix or acid leaching to obtain a mixed slurry.

[0042] Specifically, in the present application, trivalent manganese and tetravalent manganese in the first manganese source and / or the second manganese source undergo redox reaction with lithium iron phosphate in an inorganic acid environment, wherein the inorganic acid solution is a strong acid, specifically at least one of a sulfuric acid solution, a hydrochloric acid solution and a nitric acid solution. However, in industrial applications, especially in large industrial environments, sulfuric acid solutions are generally selected for reactions. The main reason is that nitric acid solution itself has strong oxidizing properties and is volatile. For lithium iron phosphate, manganese source, etc. in waste batteries in this application, it is easy to participate in the redox reaction, replace one of the reactants to react, and then interfere with the reactants and the reaction process, affecting the generation of the target product; and hydrochloric acid solution itself is volatile. In an industrial environment, on the one hand, it has relatively high requirements for the reaction environment, etc. On the other hand, for example, during acidification and roasting, due to its volatility, it cannot participate in the reaction at all under heating conditions; and sulfuric acid solution does not have the strong oxidizing properties of nitric acid solution relative to nitric acid solution and hydrochloric acid solution, and does not have the volatility of hydrochloric acid solution. Based on the above reasons, this application will choose sulfuric acid solution for reaction during actual acidification and roasting, or mainly choose sulfuric acid solution for reaction during acid leaching. Of course, hydrochloric acid can also be used. Taking sulfuric acid solution as an example, the main reactions of trivalent manganese and tetravalent manganese in the first manganese source and / or the second manganese source in this application with lithium iron phosphate in an acidic environment are as follows:

[0043] MnO 2 + 2LiFePO 4 + 2H 2 SO 4 + 2H 2 O ≜ Li 2 SO 4 + MnSO 4 + 2FePO 4 ·2H 2 O

[0044] 2MnOOH + 2LiFePO 4 + 3H 2 SO 4 ≜ Li 2 SO 4 + 2MnSO 4 + 2FePO 4 ·2H 2 O

[0045] Mn 2 O 3 +2LiFePO 4 + 3H 2 SO 4 + H 2 O ≜ Li 2 SO4 + 2MnSO 4 + 2FePO 4 ·2H 2 O

[0046] LiMnO 2 +LiFePO 4 + 2H 2 SO 4 ≜ Li 2 SO 4 + MnSO 4 + FePO 4 ·2H 2 O

[0047] By dropping sulfuric acid solution into the mixed waste, the reaction system forms an acidic environment, so that trivalent manganese, tetravalent manganese and lithium iron phosphate undergo redox reaction in an acidic environment, or roasting in an acidic environment for redox reaction, wherein the lithium iron phosphate acts as a reducing agent and the iron ions undergo redox reaction to form FePO 4 ·2H 2 O, trivalent manganese and tetravalent manganese as oxidants participate in the redox reaction and dissolve in the acidic environment in the form of manganese ions. That is, the metal elements with recycling value such as lithium ions, manganese ions and iron ions can be dissociated through the oxidizing or reducing properties of the waste battery itself. Compared with the recovery of one metal element in the waste battery alone, this application does not need to use additional oxidants or reducing agents, reduces the consumption of chemical reagents, and also achieves the purpose of recycling various metal elements.

[0048] In a specific operation, the first manganese source and / or the second manganese source can be mixed with lithium iron phosphate battery powder in a certain proportion to prepare a slurry, and then a sulfuric acid solution can be added dropwise to the mixed waste to react in an inorganic acid solution, or directly acidified and roasted in an inorganic acid environment and then mixed with water to obtain a mixed slurry, including manganese salt, lithium salt and FePO 4 ·2H 2O, etc. Specifically, taking the acidified environment roasting as an example, sulfuric acid is added to the mixed waste, wherein the amount of sulfuric acid added is S moles, and relative to the content of lithium iron phosphate in the lithium iron phosphate battery powder Tmol, the addition relationship is S=(1.1~2.2)T. It should be noted that in step S102, the molar content of trivalent manganese in the first manganese source and / or the second manganese source is M, the molar content of tetravalent manganese is N, the molar content of lithium iron phosphate in the lithium iron phosphate battery powder slurry is T, M+2N=(0.8~1.2)T; here it is mainly based on the degree of redox reaction to control the amount of lithium iron phosphate battery powder added as a reducing agent, and then control the extraction rate of each metal element recovered in the regeneration process. In addition, by controlling the amount of sulfuric acid added, the leaching rate of lithium ions in the lithium iron phosphate battery powder can also be controlled. Under experimental conditions, when the acidification and roasting are performed at 200°C and the amount of sulfuric acid added S is 1.1 times the theoretical amount (the reaction ratio in the chemical reaction equation), the lithium ion leaching rate in the lithium iron phosphate battery powder can reach more than 95% after roasting for 2 hours under the above-mentioned redox reaction conditions.

[0049] S104, dissolving an alkaline regulator in a lithium-containing solution to obtain a lithium-containing alkaline solution, adjusting the pH value of the mixed slurry with the lithium-containing alkaline solution, performing a dephosphorization treatment, and obtaining an iron phosphate slag and a lithium-manganese mixed salt solution.

[0050] Specifically, the FePO in the mixed slurry 4 ·2H 2 O and other insolubles are separated from the mixed solution. In this application, an alkaline regulator is dissolved in a lithium-containing solution to form a lithium-containing alkali solution, which is added to a mixed slurry and its pH value is adjusted to 3.5-6. The lithium-containing solution here is a mixed solution of lithium hydroxide, lithium chloride, lithium sulfate and lithium carbonate; adding an alkaline regulator to a lithium-containing solution can save water on the one hand, directly dissolve the alkaline regulator with a lithium-containing solution, and reduce the pressure of subsequent wastewater treatment. On the other hand, the alkaline regulator is dissolved in a lithium-containing solution to prevent phosphorus removal. If an alkaline regulator is directly added, the phosphorus removal agent is easily precipitated from the mixed slurry first, resulting in the phosphorus removal agent not being able to play a good role in flocculating excess metal ions and removing phosphorus in the mixed slurry. The alkaline regulator here is used to adjust the pH of the mixed slurry, and can be at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium carbonate. It is not specifically limited in this application. In actual use, it can be appropriately selected according to needs, benefits, etc. After adjusting the pH, a phosphorus removal treatment is performed to allow the phosphorus-containing ions in the mixed slurry to react with iron ions to generate FePO 4 ·2H 2O precipitates from the mixed slurry, and in an environment of pH 3.5-6, the aluminum ions and excess iron ions in the mixed slurry will also hydrolyze to generate hydroxides (such as aluminum hydroxide, ferric hydroxide or ferrous hydroxide) and precipitate, but lithium and manganese ions will not precipitate. When it comes to dephosphorization treatment, the dephosphorization agent here can be specifically polyferric sulfate, which is used to remove excess phosphate ions in the mixed slurry. The present application removes phosphorus by successively adding lithium-containing alkali solution and polyferric sulfate to the mixed slurry, and then filters the mixed slurry after dephosphorization treatment. Specifically, a filter press can be used to separate the iron phosphate slag with a small amount of hydroxide (such as aluminum hydroxide, ferric hydroxide or ferrous hydroxide) from the mixed slurry to obtain a lithium-manganese mixed salt solution. In the next step, the lithium-manganese mixed solution is further regenerated, and the separated iron phosphate slag can be purified and regenerated. The specific purification and regeneration treatment method is not described in this application. It can be used as a raw material for iron phosphate and directly traded.

[0051] S105, after removing impurities from the lithium-manganese mixed salt solution, extracting and separating to obtain a manganese salt solution and a lithium salt solution.

[0052] Specifically, the lithium manganese mixed salt solution includes lithium ions, manganese ions, sulfate ions, etc., and may also include a small amount of zinc ions, copper ions, etc. Before extracting lithium and manganese metals, the lithium manganese mixed salt solution is first purified to remove zinc ions, copper ions, etc. that may be included therein. The specific impurity removal treatment may adopt at least one of sulfide precipitation, hydrolysis precipitation or manganese powder replacement, which can be operated according to actual needs, and the present application does not impose specific restrictions on this; the impurity removal treatment is mainly to precipitate other metal ions in the lithium manganese mixed salt solution from the solution to prevent a large number of impurities in the subsequent extraction and separation treatment, which affects the purity of the recovered product.

[0053] After impurities are removed, lithium ions and manganese ions are separated by extraction. The extractants mainly considered in this application are P204 and / or P507; specifically, P204 is also known as dioctyl phosphate, dioctyl phosphate, CAS: 298-07-7; P507 is also known as 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester, molecular formula: C16H35O3P, which is an acidic phosphorus type extractant. Lithium ions and manganese ions are separated by extraction to obtain manganese salt solution and lithium salt solution respectively, which are further treated to obtain specific reusable products.

[0054] Specifically, Figure 2 As shown, the present application directly obtains the corresponding manganese salt by concentrating and crystallizing the obtained manganese salt solution; the obtained lithium salt solution can be precipitated by sodium carbonate or potassium carbonate, i.e., lithium precipitation, to obtain lithium carbonate, and the lithium salt can be separated from the solution.

[0055] Here, the zinc-containing solution obtained in step S101 is regenerated, and purification is first performed. The specific purification can be carried out by at least one of oxidation precipitation, double salt precipitation or zinc powder replacement, which can be carried out according to actual needs, and the present application does not impose specific restrictions on this; the purification is mainly to precipitate other metal ions in the zinc-containing solution from the solution to prevent electrolytic impurities from being produced during subsequent electrolytic treatment, which affects the purity of the recovered product. After the purification, the zinc in the zinc-containing solution is extracted by electrolysis, and the inorganic acid solution is left after the zinc is electrolyzed to obtain metallic zinc, which is recycled and reused in step S101, and is used to acid-leach the washed slag after the zinc-manganese battery powder is washed, and the zinc soluble in the inorganic acid (sulfuric acid) and the manganese dioxide, manganese trioxide, etc. that are insoluble in the inorganic acid (sulfuric acid) are separated, and the cycle is repeated and continuously used, which can reduce the cost of adding inorganic acid during acid leaching, further improve the efficiency of regeneration treatment, and reduce the cost of recycling and processing of subsequent materials.

[0056] In addition, combined Figure 2 It should be noted that the first fluorine-containing waste gas generated in the pretreatment of the recycled lithium-manganese dioxide battery and the second fluorine-containing waste gas generated in the pretreatment of the recycled lithium iron phosphate battery cannot be directly discharged into the air, and the fluorine-containing substances therein will pollute the air. This application collects the first fluorine-containing waste gas and the second fluorine-containing waste gas together, and then performs a secondary combustion treatment to remove the combustible organic matter therein and convert it into small molecular substances, such as carbon dioxide, water, hydrogen fluoride, phosphorus pentafluoride, etc., to obtain a slightly acidic first waste gas; here, the water washing solution obtained after washing the zinc-manganese battery powder, that is, the potassium-containing alkali solution, is applied to the first waste gas. This application specifically acts on the first waste gas by spraying the potassium-containing alkali solution, and the hydrogen fluoride and phosphorus pentafluoride therein are precipitated from the gaseous state to obtain the corresponding solution, that is, the fluorine-containing waste liquid; and other gaseous substances, that is, the third waste gas, can be directly discharged into the air after the detection reaches the direct emission standard.

[0057] After obtaining the fluorine-containing waste liquid, fluorine and phosphorus can be precipitated out through calcification. Specifically, by adding lime powder to the fluorine-containing waste liquid, the fluorine and phosphorus therein are precipitated out in the form of calcium fluoride and calcium carbonate, and the calcium fluoride and calcium phosphate can be separated by filtration to obtain a mixed alkali solution. It should be noted that the lime powder here is industrial lime, which is generally a mixture of quicklime and slaked lime, that is, a mixture of calcium oxide (commonly known as quicklime) and calcium hydroxide (commonly known as slaked lime, slaked lime). The mixed alkali solution (mainly including potassium ions, calcium ions, etc.) is directly recovered, and the calcium ions therein are precipitated out by decalcifying the mixed alkali solution, leaving a second potassium-containing alkali solution. Such as Figure 2As shown, the second potassium-containing alkali solution obtained here can be directly recovered, or it can be used to treat the first waste gas obtained after the secondary combustion of the fluorine-containing waste gas after recovery. Specifically, it has the same effect as the first potassium-containing alkali solution after the zinc-manganese battery powder is washed in the aforementioned step S101, and is used to spray the first acidic waste gas to settle the fluorine and phosphorus in the first acidic waste gas. Of course, it can also be directly recovered, and the second potassium-containing alkali solution can be directly neutralized by hydrochloric acid, and finally concentrated and crystallized to obtain a potassium chloride product for recovery. In addition, the treatment agent used in the mixed alkali solution decalcification treatment includes at least one of carbon dioxide, potassium carbonate, and sodium carbonate. Considering that the introduction of other ions will increase the difficulty of recovery and separation, and easily reduce the purity of the recovered product, carbon dioxide and / or potassium carbonate are mainly used as treatment agents for decalcification.

[0058] Compared with the prior art, the combined treatment method for waste batteries proposed in this application has the following advantages:

[0059] The recovered zinc-manganese battery is pretreated to obtain a first potassium-containing alkaline solution, a zinc-containing solution and a first manganese source, the recovered lithium-manganese dioxide battery is pretreated to obtain a lithium-containing solution and a second manganese source, and the recovered lithium iron phosphate battery is pretreated to obtain lithium iron phosphate battery powder; the first manganese source and / or the second manganese source are mixed with the lithium iron phosphate battery powder to obtain a mixed waste; an inorganic acid solution is added to the mixed waste, and after acidification and roasting, water is added to mix or directly acid leaching is performed to obtain a mixed slurry; an alkaline regulator is dissolved in the lithium-containing solution to obtain a lithium-containing alkaline solution, and the pH value of the mixed slurry is adjusted to 3.5-6.0 with the lithium-containing alkaline solution, and then a phosphorus removal treatment is performed to obtain iron phosphate slag and a lithium-manganese mixed salt solution; the lithium-manganese mixed salt solution is extracted and separated to obtain a manganese salt solution and a lithium salt solution. Compared with the separate recovery of manganese in zinc-manganese batteries and lithium-manganese dioxide batteries, which requires reduction roasting or leaching with a reducing agent under acidic conditions, and the separate recovery of lithium in lithium iron phosphate batteries, which requires oxidative roasting or leaching with an oxidant under acidic conditions, the combined regeneration process makes full use of the oxidizing properties of zinc-manganese batteries and lithium-manganese dioxide batteries and the reducibility of lithium iron phosphate batteries, and performs redox reactions in an acidic environment, which can save the reducing agent required for manganese recovery and the oxidizing agent required for lithium recovery, and can reduce the recycling costs of zinc-manganese batteries, lithium-manganese dioxide batteries and lithium iron phosphate batteries, and even make the recycling of lithium iron phosphate batteries profitable.

[0060] In view of this, the present application will analyze the beneficial effects of the present application from specific embodiments, as follows. In addition, it should be noted that in actual industrial recycling, such as Figure 2The process shown is a continuous cycle, the initial raw materials are also continuously pre-treated and added to the whole process, various neutralization, acid leaching, acidification treatment is in the process of uninterrupted processing; the obtained product mother liquor, such as lithium salt solution, manganese salt solution will be continuously generated, the acid solution generated after the electrolysis of the zinc-containing solution is also continuously generated, and can be continuously used for acid leaching treatment of the washed slag after the zinc-manganese battery powder is washed; therefore, all the recovered products are not all recovered at once, and the final recovered product in the following embodiment is only the recovered product of one stage, not completely recovered; by Figure 2 The process shown is continuously repeated, and the overall recycling rate of the waste battery joint recycling in this application can be high and economic benefits can be achieved.

[0061] Example 1

[0062] A method for combined regeneration of waste batteries comprises the following steps:

[0063] 1. The recovered zinc-manganese battery is pretreated to obtain a first potassium-containing alkali solution, a zinc-containing solution and a first manganese source, the recovered lithium-manganese dioxide battery is pretreated to obtain a lithium-containing solution and a second manganese source, and the recovered lithium iron phosphate battery is pretreated to obtain lithium iron phosphate battery powder; at the same time, the first fluorine-containing waste gas generated in the pretreatment of the lithium-manganese dioxide battery and the second fluorine-containing waste gas generated in the pretreatment of the lithium iron phosphate battery are collected and then secondary burned to generate the first waste gas, and the first waste gas is sprayed with the first potassium-containing alkali solution obtained after the pretreatment of the zinc-manganese battery to obtain fluorine-containing waste liquid and a third waste gas. The third waste gas can be directly discharged into the atmosphere after being tested to meet the emission standards, and lime powder is added to the fluorine-containing waste liquid to precipitate the fluorine and phosphorus therein in the form of calcium fluoride and calcium phosphate.

[0064] 2. A first manganese source, wherein the content of trivalent manganese in the first manganese source is 5 mol and the content of tetravalent manganese is 4 mol, is mixed with lithium iron phosphate battery powder containing 13 mol of lithium iron phosphate to obtain a mixed waste.

[0065] 3. Add 18 mol of sulfuric acid solution to the mixed waste, acidify and roast, react at 200°C for 2 hours, add water and mix to obtain a mixed slurry.

[0066] 4. After adding an appropriate amount of polyferric sulfate to the mixed slurry, dissolve the caustic soda flakes in the lithium-containing solution to obtain a lithium-containing alkali solution, and use the lithium-containing alkali solution to adjust the pH value of the mixed slurry to 3.5-6.0 for dephosphorization treatment to obtain iron phosphate slag and lithium manganese mixed salt solution.

[0067] 5. After removing impurities from the lithium-manganese mixed salt solution, use P204 and P507 to extract and separate in sequence to obtain manganese salt solution and lithium salt solution.

[0068] 6. The manganese salt solution is directly concentrated and crystallized to obtain manganese sulfate; the raffinate, i.e., the lithium salt solution, is subjected to carbonation treatment, i.e., by adding sodium carbonate, lithium ions are precipitated in the form of lithium carbonate.

[0069] The zinc-containing solution produced in step 1 is first purified by oxidation precipitation and zinc powder replacement to remove impurities therein, and then electrolyzed to obtain metallic zinc and sulfuric acid solution. The sulfuric acid solution produced here will be used as the acid leaching raw material after zinc-manganese battery powder is washed to save costs.

[0070] In this embodiment, the mass of manganese sulfate recovered is 1476g, and the purity meets the first-class product index of HG / T 4823-2015; the mass of lithium carbonate is 402g, and the purity meets the requirements of YS / T 582-2013; the mass of metallic zinc is 308g, and the purity meets the requirements of zinc ingots with a grade of Zn99.99 in GB / T470-2008.

[0071] Example 2

[0072] A method for combined regeneration of waste batteries, which differs from Example 1 in that a first manganese source and a second manganese source, wherein the content of trivalent manganese in the first manganese source is 2 mol and the content of tetravalent manganese is 4 mol, and the content of trivalent manganese in the second manganese source is 3 mol and the content of tetravalent manganese is 4 mol, are mixed with lithium iron phosphate battery powder containing 26 mol of lithium iron phosphate, and water is added and stirred to obtain a mixed slurry. 28 mol of sulfuric acid solution is slowly added to the mixed slurry, and stirred and reacted at 80°C for 8 hours.

[0073] In this embodiment, the mass of manganese sulfate recovered is 2145g, and the purity meets the first-class product index of HG / T 4823-2015; the mass of lithium carbonate is 768g, and the purity meets the requirements of YS / T 582-2013; the mass of metallic zinc is 195g, and the purity meets the requirements of zinc ingots with a grade of Zn99.99 in GB / T470-2008.

[0074] Example 3

[0075] A method for combined regeneration of waste batteries, which differs from Example 1 in that a first manganese source and a second manganese source, wherein the content of trivalent manganese in the first manganese source is 2 mol and the content of tetravalent manganese is 1 mol, and the content of trivalent manganese in the second manganese source is 2 mol and the content of tetravalent manganese is 2 mol, are mixed with lithium iron phosphate battery powder containing 10.8 mol of lithium iron phosphate to obtain mixed waste. 15 mol of sulfuric acid solution is added to the mixed waste, acidified and roasted, reacted at 200°C for 2 hours, and water is added to mix to obtain a mixed slurry.

[0076] In this embodiment, the mass of manganese sulfate recovered is 1142g, and the purity meets the first-class product index of HG / T 4823-2015; the mass of lithium carbonate is 378g, and the purity meets the requirements of YS / T 582-2013; the mass of metallic zinc is 98g, and the purity meets the requirements of zinc ingots with a grade of Zn99.99 in GB / T470-2008.

[0077] Example 4

[0078] A method for combined regeneration of waste batteries, which differs from Example 2 in that a second manganese source is taken, wherein the content of trivalent manganese in the second manganese source is 5 mol, and the content of tetravalent manganese is 8 mol, and lithium iron phosphate battery powder containing 20 mol of lithium iron phosphate is mixed, and water is added and stirred to obtain a mixed slurry. 28 mol of sulfuric acid solution is slowly added to the mixed slurry, and the reaction is stirred at 80°C for 8 hours. In addition, the solution used for stripping is a 4 mol / L hydrochloric acid solution.

[0079] In this embodiment, the mass of manganese chloride recovered is 2570g, and the purity meets the HG / T 3816-2011 Class I qualified product index; the mass of lithium carbonate is 752g, and the purity meets the requirements of YS / T 582-2013.

[0080] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element. The "first" and "second" in this article are not order, but are only used to distinguish different names for distinction.

[0081] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0082] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for the combined recycling treatment of waste batteries, characterized in that, it includes: Pre-treating the recycled zinc-manganese batteries to obtain a first potassium-containing alkali solution, a zinc-containing solution and a first manganese source, pre-treating the recycled lithium-manganese dioxide batteries to obtain a lithium-containing solution and a second manganese source, and pre-treating the recycled lithium iron phosphate batteries to obtain lithium iron phosphate battery powder; taking the first manganese source and / or the second manganese source and mixing them with the lithium iron phosphate battery powder to obtain a mixed waste, wherein the content of trivalent manganese in the first manganese source and / or the second manganese source is M moles, the content of tetravalent manganese is N moles, and the content of lithium iron phosphate in the lithium iron phosphate battery powder is T moles, and M + 2N = (0.8 - 1.2)T; adding an inorganic acid solution to the mixed waste, performing acidification roasting, then adding water and mixing or directly acid leaching to obtain a mixed slurry; dissolving an alkaline regulator in the lithium-containing solution to obtain a lithium-containing alkali solution, and adjusting the pH value of the mixed slurry to 3.5 - 6.0 with the lithium-containing alkali solution for phosphorus removal treatment to obtain iron phosphate slag and a lithium-manganese mixed salt solution; Performing extraction separation on the lithium-manganese mixed salt solution to obtain a manganese salt solution and a lithium salt solution.

2. The method for the combined recycling treatment of waste batteries according to claim 1, characterized in that, The pre-treating the recycled zinc-manganese batteries to obtain a first potassium-containing alkali solution, a zinc-containing solution and a first manganese source includes: sequentially performing crushing, drying and sorting on the recycled zinc-manganese batteries to obtain zinc-manganese battery powder; washing the zinc-manganese battery powder with water to obtain a first potassium-containing alkali solution and a water-washed residue; performing acid leaching on the water-washed residue to obtain a zinc-containing solution and a first manganese source.

3. The method for the combined recycling treatment of waste batteries according to claim 1, characterized in that, The pre-treating the recycled lithium-manganese dioxide batteries to obtain a lithium-containing solution and a second manganese source, and pre-treating the recycled lithium iron phosphate batteries to obtain lithium iron phosphate battery powder; further includes: collecting the first fluorine-containing waste gas generated during the pre-treatment of the recycled lithium-manganese dioxide batteries and the second fluorine-containing waste gas generated during the pre-treatment of the recycled lithium iron phosphate batteries; performing secondary combustion treatment on the first fluorine-containing waste gas and the second fluorine-containing waste gas to obtain a first waste gas; spraying and treating the first waste gas with the first potassium-containing alkali solution to obtain a fluorine-containing waste liquid and a third waste gas.

4. The method for the combined recycling treatment of waste batteries according to claim 3, characterized in that, further includes: Adding lime powder to the obtained fluorine-containing waste liquid, filtering to obtain a filter residue and a mixed alkali solution; Performing calcium removal treatment on the mixed alkali solution to obtain calcium carbonate and a second potassium-containing alkali solution.

5. The method for the combined recycling treatment of waste batteries according to claim 4, characterized in that, The treatment agent used for the calcium removal treatment of the mixed alkali solution includes at least one of carbon dioxide, potassium carbonate, and sodium carbonate.

6. The method for the combined recycling treatment of waste batteries according to claim 2, characterized in that, The method further includes: purifying the zinc-containing solution and then performing electrolysis to obtain electrolytic metallic zinc and an acid solution; wherein the purification treatment includes one or more of oxidation precipitation, double salt precipitation or zinc powder replacement.

7. The combined recycling method for waste batteries according to claim 6, It is characterized in that The acid solution can also be used to carry out acid leaching treatment on the water-washed slag.

8. The combined recycling method for waste batteries according to claim 1, It is characterized in that The extractant used in the extraction and separation process includes P204 and / or P507.

9. The combined recycling method for waste batteries according to claim 1, It is characterized in that The inorganic acid solution is at least one of a sulfuric acid solution, a hydrochloric acid solution and a nitric acid solution.

10. The combined recycling method for waste batteries according to claim 1, It is characterized in that The alkaline regulator is at least one of sodium hydroxide, sodium carbonate, potassium hydroxide and potassium carbonate.

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