Process for the recovery of active material from waste batteries by desorption

Abstract

A method for recovering an active material from a waste battery by desorption, comprising the following steps: 1) mixing a positive electrode current collector film and a negative electrode current collector film of a waste lithium-ion battery with carbon tetrachloride in a reaction device; 2) introducing chlorine into the reaction device in step 1) for reaction; 3) removing the remaining films after the reaction in step 2) and performing solid-liquid separation on the remaining materials in the reaction device to obtain a solution of aluminum chloride in carbon tetrachloride and a first positive electrode desorption powder;4) Soaking the foils and the first positive electrode desorption powder in step 3) in water to obtain soaked foils, removing the soaked foils, and performing solid-liquid separation on the remaining materials to obtain a lithium salt solution and a second positive electrode desorption powder; and 5) reacting the foils soaked in step 4) with a nitric acid solution and performing solid-liquid separation to obtain a copper nitrate solution and a negative electrode desorption powder; wherein in step 1), the positive electrode current collector foil and the negative electrode current collector foil of the waste lithium-ion battery are obtained by discharging and disassembling the waste lithium-ion battery; and in step 1), the positive electrode current collector foil comprises an aluminum foil and the negative electrode current collector foil comprises a copper foil.

Description

TECHNICAL FIELDThe present invention belongs to the field of battery recycling and relates in particular to a method for recovering an active material from a used battery by desorption.BACKGROUNDLithium ion batteries have a complex structure and are composed of shells, separators, positive electrodes, negative electrodes, etc. The negative electrode is composed of graphite, binder, conductive material, and copper foil as current collectors, and the positive electrode is produced by coating active material powder, binder, and conductive material on aluminum foil as current collectors. The cathode active powder is mainly composed of LiCoO 2, LiNiO 2, LiMnO 2, LiFePO 4 and LiNi x Co y Mn 1-x-y O 2, etc. In recycling old batteries, the various components must be separated by a variety of methods.Old lithium ion batteries generally have a certain residual voltage. If not properly treated, self-ignition and explosion may easily occur, jeopardizing safety of the personnel. Therefore, the pretreatment of old lithium-ion batteries generally comprises the predischarge, comminution and disassembly of the batteries and also the desorption of current collectors.In the mechanical comminution and sorting, a 2-3-fold comminution is required to improve the recovery rate of active material powder in order to reduce the particle size of the debris. However, this inevitably increases the difficulty of sorting and reduces the recovery rate of the separated components. In the case of a single mechanical comminution and sorting, it is difficult to take account of both the recovery rate and the degree of recovery of the active substance. Therefore, it is particularly important to desorb the active ingredient powder from current collectors by other technical means.Currently, separation of active materials and current collectors mainly focuses on three aspects: (1) Due to the properties of the metal aluminum, which can dissolve in alkaline solution, the positive electrode foil can be soaked in alkaline solution to separate the positive electrode powder and the current collector.This method has the advantage of consuming little energy and being easy to handle, but the aluminum foil of the current collector enters the solution in the form of ions, which requires further recycling. In addition, this process requires a large amount of caustic. In order to avoid secondary contamination by the brine, a neutralization treatment is required, which causes additional costs. In order to avoid contamination of the powder by the introduced alkali, the desorbed active ingredients should be completely rinsed out during the filtration process or neutralized with acid. (2) Organic solvents are used to dissolve the binder polyvinylidene fluoride (PVDF), so that the metal foil of the current collector can be recovered in solid form. However, the organic solvents are usually expensive and are not suitable for industrial applications. Moreover, dissolution with organic solvents is not suitable for the separation of all kinds of binders. For example, when the binder used in lithium ion batteries is polytetrafluoroethylene (PTEE), dissolution with organic solvents such as N-methylpyrrolidone (NMP) is negligible. (3) The direct heating to a certain temperature in the air may deactivate the binder to separate the aluminum foil of the current collector. However, the pyrolysis process generally requires a high temperature, and the binder and the organic electrolyte decompose to generate toxic and harmful gases such as HF upon high temperature pyrolysis, thus requiring additional exhaust gas purifying and treating apparatuses.SUMMARYThe subject matter described in detail herein follows. This summary is not intended to limit the scope of the claims.In order to overcome the problem that the active material cannot be efficiently recovered in prior art waste batteries, the examples of the present disclosure provide a method for recovering an active material from a waste battery by desorption.In order to achieve the above object, the technical solution used in the present invention is:A method for recovering an active material from a waste battery by desorption, comprising the steps of: 1) mixing a positive electrode current collector foil and a negative electrode current collector foil of the lithium ion waste battery with carbon tetrachloride in a reaction apparatus; 2) introducing chlorine into the reaction apparatus in step 1) to react; 3) removing the remaining foils after the reaction in step 2) and performing solid-liquid separation on the remaining materials in the reaction apparatus to obtain a solution of aluminum chloride in carbon tetrachloride and a first desorption powder of the positive electrode; 4) soaking the foils and the first positive electrode desorption powder in Step 3) in water to obtain soaked foils, removing the soaked foils and performing solid-liquid separation on the remaining materials to obtain a lithium salt solution and a second positive electrode desorption powder; and 5) reacting the foils soaked in Step 4) with a nitric acid solution and performing solid-liquid separation to obtain a copper nitrate solution and a negative electrode desorption powder;wherein, in step 1), the sheet of the positive electrode current collector and the sheet of the negative electrode current collector of the waste lithium ion battery are obtained by discharging and disassembling the waste lithium ion battery; andIn step 1), the positive electrode current collector foil comprises an aluminum foil and the negative electrode current collector foil comprises a copper foil.In the method for recovering the active material from the waste battery by desorption in Step 1), the waste lithium ion battery preferably comprises at least one of the following batteries: ternary lithium ion battery, lithium iron phosphate battery, lithium cobalt oxide battery, lithium manganate battery and lithium nickelate battery; more preferably, the lithium ion waste battery is at least one of lithium iron phosphate battery, ternary lithium battery and lithium cobalt oxide battery; still more preferably, the lithium ion waste battery is lithium iron phosphate battery.Preferably, in the method for recovering the active material from the waste battery by desorption in step 1), the amount of carbon tetrachloride needs to be so large that the carbon tetrachloride solution can cover the film.Preferably, in the method for recovering the active material from the waste battery by desorption in step 2), the reaction temperature is 70-120° C.; more preferably, the reaction temperature is 80-120° C. The temperature of the reaction may be 80° C., 90° C., 100° C., 110° C., or 120° C.Preferably, in the method for recovering the active material from the waste battery by desorption, the top of the reaction device is provided with a condenser; more preferably, the condensation temperature of the condenser is ≤60° C.; more preferably, the condensation temperature of the condenser is ≤55° C.; even more preferably, the condensation temperature of the condenser is ≤50° C.In the method for recovering the active material from the waste battery by desorption in step 2), the chlorine is preferably dry chlorine.In the method for recovering the active material from the waste battery by desorption in step 2), the reaction preferably ends when the solids are no longer reduced.In the method for recovering the active material from the old battery by desorption, step 3) preferably comprises another step for separating aluminum chloride and carbon tetrachloride: evaporating the solution of aluminum chloride in carbon tetrachloride to obtain anhydrous aluminum chloride and carbon tetrachloride; more preferably under a condition of 70-75°C, evaporating the solution of aluminum chloride in carbon tetrachloride to obtain anhydrous aluminum chloride and carbon tetrachloride.Preferably, in the method for recovering the active material from the old battery by desorption in step 4), the soaking time in water is 6-40 minutes; more preferably, the soaking time in water is 8-35 minutes; still more preferably, the soaking time in water is 10-30 minutes.In the method for recovering the active material from the old battery by desorption in step 4), the water is preferably deionized water.Preferably, in the method for recovering the active material from the waste battery by desorption in step 5), the concentration of the nitric acid solution is 0.5-9 mol / L; more preferably, the concentration of the nitric acid solution is 0.8-8.5 mol / L; still more preferably, the concentration of the nitric acid solution is 1-8 mol / L.Preferably, in the method for recovering the active material from the waste battery by desorption in step 5), it may also comprise heating the foils soaked in step 4) under an inert gas atmosphere of nitrogen / argon, and screening to obtain a desorption powder of the negative electrode and a copper foil; more preferably, the temperature of heating is 50-550° C. and the duration of heating is 30-90 minutes.The advantageous effects of the examples of the present disclosure are as follows. 1. in the method for recovering an active material from a waste battery by desorption of the examples of the present invention, the waste battery only needs to be discharged and disassembled, and no crushing process is required, thereby avoiding the problem of the sorting difficulties caused by the reduced particle size after crushing 2-3 times. Moreover, the cathode and anode materials can be effectively recovered, and the product has a high economic value. 2. in the method for recovering an active material from a waste battery by desorption according to the examples of the present invention, the aluminum foil of the positive current collector reacts by mixing the decomposed foils with carbon tetrachloride and reacting with chlorine with chlorine to produce aluminum chloride, while the negative copper foil does not react with chlorine. Aluminum chloride is easily soluble in carbon tetrachloride, so that no dense oxide film is formed which could cause a break in the reaction. In the reaction of chlorine and aluminum foil, the positive electrode active material gradually falls off while the negative electrode does not change, thereby realizing the separation of the positive and negative electrodes, avoiding the steps of crushing and sorting, and reducing equipment investment. 3. In the method for recovering an active material from a waste battery by desorption of the examples of the present invention, by evaporating carbon tetrachloride at low temperature, anhydrous aluminum chloride having a high economic value is recovered, and carbon tetrachloride can be reused after recycling. 4. in the method for recovering an active material from a waste battery by desorption according to the examples of the present invention, chlorine may further oxidize the cathode material during the reaction. In the subsequent soaking in water, lithium salts, particularly lithium iron phosphate cathode material, can be directly extracted, and iron phosphate and lithium chloride can be recovered without destroying the olivine skeletal structure of the iron phosphate, which can be used directly as a precursor of the cathode material sintered with the lithium source to regenerate the lithium iron phosphate cathode material. 5. in the method for recovering an active material from a waste battery by desorption according to the examples of the present invention, the temperature during the reaction is controlled to be below 120° C., thereby avoiding melting of the binder, leaving the negative electrode current collector unchanged, and facilitating separation of the anode materials. 6.In the method for recovering an active material from a waste battery by desorption of the examples of the present invention, nitric acid reacts with the copper foil of the negative electrode current collector, and thereby desorption is realized to obtain a negative electrode desorption powder.Other aspects will become apparent upon reading and understanding the drawings and the detailed description.BRIEF DESCRIPTION OF THE DRAWINGSThe accompanying drawings serve to further understand the present technical solution and form part of the description. Together with the application examples, they serve to explain the present technical solution and do not represent a restriction of the present technical solution. FIG. 1 is a schematic diagram of the method for recovering an active material from a waste battery by desorption in the examples of the present invention.DETAILED DESCRIPTIONThe content of the present invention will be described below in more detail by way of specific examples. Unless otherwise indicated, the raw materials or equipment used in the examples may be obtained from the usual commercial sources or may be obtained by methods known in the art. Unless otherwise indicated, the tests or test methods are conventional in the art.Example 1Referring to the schematic diagram of FIG. 1, the desorption recovery method of an active material from a waste battery in this example includes the following steps: 1) After the waste lithium iron phosphate battery has been discharged and decomposed, the foils of the positive and negative electrode current collectors were taken out and placed in a closed reaction vessel. Carbon tetrachloride was added to the reaction vessel until the foils of the positive and negative electrode current collectors were covered. 2) Dry chlorine was introduced into the reaction vessel, and the reaction temperature in the vessel was controlled to 120° C. At the top of the reaction vessel, a condenser having a condensation temperature of 50°C or less was attached, and the reaction was terminated when the solid was no longer reduced. After completion of the reaction in Step 2), the system was cooled to room temperature, and the unreacted films were removed. Solid-liquid separation was performed to obtain a solution of aluminum chloride in carbon tetrachloride and a first positive electrode desorption powder. The solution of aluminum chloride in carbon tetrachloride was evaporated at a low temperature to separate aluminum chloride and carbon tetrachloride to obtain anhydrous aluminum chloride, and carbon tetrachloride was recovered. 4) The unreacted foils and the first positive electrode desorption powder of Step 3) were soaked in deionized water for 10 minutes, and the soaked foils were removed. Solid-liquid separation was performed to obtain a lithium salt solution and a delithiated positive electrode second desorption powder. 5) The foils soaked in Step 4) were put into a nitric acid solution having a concentration of 8 mol / L to react. After completion of the reaction, solid-liquid separation was performed to obtain a copper nitrate solution and a negative electrode desorption powder.Example 2Referring to the schematic diagram of FIG. 1, the method for recovering an active material from a waste battery by desorption in this example includes the following steps: 1) After the ternary lithium ion waste battery is discharged and decomposed, the foils of the positive and negative electrode current collectors are taken out and placed in a closed reaction vessel. Carbon tetrachloride was added to the reaction vessel until the foils of the positive and negative electrode current collectors were covered. 2) Dry chlorine was introduced into the reaction vessel, and the reaction temperature in the vessel was controlled to 100° C. A condenser having a condensation temperature of 50°C or less was attached to the top of the reaction vessel, and the reaction was terminated when the solid was no longer reduced. After completion of the reaction in Step 2), the system was cooled to room temperature, and the unreacted films were removed. Solid-liquid separation was performed to obtain a solution of aluminum chloride in carbon tetrachloride and a first positive electrode desorption powder. The solution of aluminum chloride in carbon tetrachloride was evaporated at a low temperature to separate aluminum chloride and carbon tetrachloride to obtain anhydrous aluminum chloride, and carbon tetrachloride was recovered. 4) The unreacted foils and the first positive electrode desorption powder of Step 3) were soaked in deionized water for 20 minutes, and the soaked foils were removed. Solid-liquid separation was performed to obtain a lithium salt solution and a second positive electrode desorption powder. 5) The foils soaked in Step 4) were put into a nitric acid solution having a concentration of 4 mol / L to react. After completion of the reaction, solid-liquid separation was performed to obtain a copper nitrate solution and a negative electrode desorption powder.Example 3Referring to the schematic diagram of FIG. 1, the desorption recovery method of an active material from a waste battery in this example includes the following steps: 1) After the waste lithium cobalt oxide battery is discharged and decomposed, the foils of the positive and negative electrode current collectors are taken out and placed in a closed reaction vessel. Carbon tetrachloride was added to the reaction vessel until the foils of the positive and negative electrode current collectors were covered. 2) Dry chlorine was introduced into the reaction vessel, and the reaction temperature in the vessel was controlled to 80°C. A condenser having a condensation temperature of 50°C or less was attached to the top of the reaction vessel, and the reaction was terminated when the solid was no longer reduced. After completion of the reaction in Step 2), the system was cooled to room temperature, and the unreacted films were removed. Solid-liquid separation was performed to obtain a solution of aluminum chloride in carbon tetrachloride and a first positive electrode desorption powder. The solution of aluminum chloride in carbon tetrachloride was evaporated at a low temperature to separate aluminum chloride and carbon tetrachloride to obtain anhydrous aluminum chloride, and carbon tetrachloride was recovered. 4) The unreacted foils and the first positive electrode desorption powder of Step 3) were soaked in deionized water for 30 minutes, and the soaked foils were removed. Solid-liquid separation was performed to obtain a lithium salt solution and a second positive electrode desorption powder. 5) The foils soaked in Step 4) were put into a nitric acid solution having a concentration of 1 mol / L to react. After completion of the reaction, solid-liquid separation was performed to obtain a copper nitrate solution and a negative electrode desorption powder.

Claims

A method for recovering an active material from a waste battery by desorption, comprising the steps of: 1) mixing a positive electrode current collector foil and a negative electrode current collector foil of a lithium ion waste battery with carbon tetrachloride in a reaction apparatus; 2) introducing chlorine into the reaction apparatus in step 1) to react; 3) removing the remaining foils after the reaction in step 2) and performing solid-liquid separation on the remaining materials in the reaction apparatus to obtain a solution of aluminum chloride in carbon tetrachloride and a first desorption powder of the positive electrode; 4) soaking the foils and the first positive electrode desorption powder in Step 3) in water to obtain soaked foils, removing the soaked foils, and performing solid-liquid separation on the remaining materials to obtain a lithium salt solution and a second positive electrode desorption powder; and 5) reacting the foils soaked in Step 4) with a nitric acid solution and performing solid-liquid separation to obtain a copper nitrate solution and a negative electrode desorption powder; wherein in Step 1), the positive electrode current collector foil and the negative electrode current collector foil of the waste lithium ion battery are obtained by discharging and decomposing the waste lithium ion battery; and in step 1), the positive electrode current collector foil includes an aluminum foil and the negative electrode current collector foil includes a copper foil.The method for recovering the active material from the waste battery by desorption according to claim 1, wherein in step 1), the waste lithium ion battery comprises at least one of the following batteries: ternary lithium ion battery, lithium iron phosphate battery, lithium cobalt oxide battery, lithium manganate battery, or lithium nickelate battery.The method for recovering the active material from the waste battery by desorption according to claim 1, wherein in step 2), the reaction temperature is 70°C - 120°C.The method for recovering the active material from the waste battery by desorption according to claim 1, wherein a head of the reaction device is provided with a condenser.The method for recovering the active material from the waste battery by desorption according to claim 4, wherein the condensation temperature of the condenser is less than or equal to 60°C.The method for recovering the active material from the waste battery by desorption according to claim 1, wherein step 3) further comprises a step of separating aluminum chloride and carbon tetrachloride: evaporating the solution of aluminum chloride in carbon tetrachloride to obtain anhydrous aluminum chloride and carbon tetrachloride.The method for recovering the active material from the waste battery by desorption according to claim 1, wherein in step 4), the soaking time in water is 6 - 40 minutes.The method for recovering the active material from the waste battery by desorption according to claim 1, wherein in step 5), the concentration of the nitric acid solution is 0.5 - 9 mol / L.The method for recovering the active material from the waste battery by desorption according to claim 6, wherein under a condition of 70°C - 75°C, the solution of aluminum chloride in carbon tetrachloride is evaporated to obtain anhydrous aluminum chloride and carbon tetrachloride.

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