Method for extracting and recycling metal elements in lithium battery by using chlorination process

Abstract

The invention discloses a method for extracting and recovering metal elements in a lithium battery by using a chlorination method, and belongs to the technical field of lithium battery recovery, the method comprises the following steps: step 1, roasting a lithium battery positive plate to remove organic matters, and stripping to remove aluminum foil to obtain electrode material powder; step 2, placing the electrode material powder on a carrier of a Joule heating device, carrying out thermal shock treatment in a chlorine atmosphere, and heating and chlorinating in stages in the treatment process; step 3, desublimating gas generated after chlorination in each stage; and 4, adding the desublimated solid in each stage into deionized water, mixing, adding a sodium carbonate aqueous solution, collecting the precipitate, washing, and drying to obtain a metal salt product. Based on the characteristics that Joule heat can rapidly heat and accurately control the temperature, by combining the difference between the temperature of chlorination reaction of different metal oxides and the gasification temperature of a chlorinated product, staged gasification desublimation treatment is achieved, different metal chlorides are obtained, and accurate and efficient purification is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium battery recycling, and specifically relates to a method for extracting and recycling metal elements in lithium batteries by using a chlorination method. Background Art

[0002] With the extensive use of lithium-ion batteries in the field of electric energy and energy storage, the environmental and resource problems caused by waste lithium-ion batteries have become increasingly prominent. The green and efficient recovery of valuable metals in waste lithium-ion batteries has great practical significance in terms of comprehensive resource utilization, energy conservation, environmental protection and sustainable development, and has gradually become a research hotspot in countries around the world.

[0003] At present, the recycling process of waste lithium-ion batteries is mainly pre-treatment-leaching-wet recovery. Wet recovery of valuable metals in the leachate is the key link in the recycling process of waste lithium-ion batteries, and it is also the focus and difficulty of research in recent years. The main methods include solvent extraction, precipitation, electrolysis, ion exchange and salting out. In the process of using these methods to treat waste lithium-ion batteries, secondary pollution such as waste liquid and waste residue will inevitably be generated, and the purification efficiency is low. At present, due to the increasingly serious environmental pollution, in order to achieve green and efficient recycling of waste lithium-ion batteries, it is necessary to minimize the harm of secondary pollution while maximizing resource utilization.

[0004] The Chinese invention patent with publication number CN103060567B discloses a method for extracting valuable metals from waste lithium-ion battery positive plates, which uses a chlorination method to efficiently separate high-purity aluminum salts and other valuable metal compounds, but the subsequent treatment of the condensed products of the chlorination process requires the use of different precipitants to achieve the separate recovery of different metal elements. The precipitation recovery process is complicated, and lithium carbonate needs to be used as a precipitant for cobalt, nickel and manganese, etc., and the recovery cost is high. The patent with publication number CN115149134A discloses a method, device and application of high-temperature chlorination roasting of waste lithium batteries, wherein waste lithium battery materials are roasted in a chlorine atmosphere, the roasted reactants are dissolved in water to obtain a first solution, and metals are recovered from the first solution, wherein the recovery rate of metal lithium can reach 95.06%, the recovery rate of metal manganese can reach 97.01%, the recovery rate of metal nickel can reach 82.02%, and the recovery rate of metal cobalt can reach 69.16%. This method avoids the use of reducing agents, does not produce a large amount of leaching solution, and is environmentally friendly, but the recovery rate of metal elements still needs to be improved. Summary of the invention

[0005] The purpose of the present invention is to provide a method for extracting and recovering metal elements in lithium batteries using a chlorination method, thereby achieving efficient recovery of multiple metal elements in lithium battery special materials while reducing secondary pollution and drug consumption costs.

[0006] The purpose of the present invention can be achieved through the following technical solutions: The present invention provides a method for extracting and recovering metal elements in a lithium battery using a chlorination method, comprising the following steps: Step 1: calcining the positive electrode sheet of the lithium battery to remove organic matter, and peeling off the aluminum foil to obtain electrode material powder; Step 2: placing the electrode material powder on a carrier of a Joule heat device and subjecting it to a thermal shock treatment in a chlorine atmosphere, wherein the treatment process is carried out by heating and chlorination in stages, and the temperature range is 350-1400°C; Step 3: condense the gas produced after chlorination at each stage, and the condensation temperature is 50-970°C; Step 4: Add the solids after desublimation in each stage into deionized water, add sodium carbonate aqueous solution after mixing, adjust the pH to 3.5-10.0, perform precipitation reaction, collect the precipitate, wash and dry to obtain the metal salt product.

[0007] The active component of the lithium battery positive electrode plate is at least one of lithium iron phosphate, lithium cobalt oxide, lithium iron manganese phosphate, and lithium nickel cobalt manganese oxide.

[0008] In step one, the calcination temperature is 650-700°C, and the calcination time is 3-6h. The positive electrode sheet generally contains a binder, wherein the decomposition temperature range of the binder PVDF is 350-600°C, and the binder AB glue begins to decompose at 650°C. After decomposition, the bonding performance fails, thereby achieving the peeling of the aluminum foil and the electrode material powder.

[0009] The positive electrode materials of lithium batteries contain iron oxide, ferrous oxide, cobalt oxide, nickel oxide, lithium oxide, manganese oxide, aluminum oxide and carbon. These metal oxides will generate chlorides under high temperature conditions in a chlorine atmosphere. The reaction equation is: MO x +xCl 2 =MCl 2x +x / 2O 2 ; MO x +xCl 2 +xC=MCl 2x +xCO.

[0010] Among them, the temperatures of various chlorination reactions and the gasification temperatures of chlorination products are different.

[0011] The staged heating and chlorination temperature control of the thermal shock treatment is as follows: the temperature of the first stage is 350-380°C (Fe), constant temperature 10-20s, the temperature of the second stage is 700-900°C (Al), constant temperature 30-50s, the temperature of the third stage is 980-1000°C (Ni), constant temperature 10-20s, the temperature of the fourth stage is 1050-1150°C (CO), constant temperature 10-20s, the temperature of the fifth stage is 1200-1280°C (Mn), constant temperature 10-20s, the temperature of the sixth stage is 1350-1400°C (Li), constant temperature 10-20s, and the heating rate of the thermal shock treatment is 10 3 ℃ / s.

[0012] At the first stage temperature, iron oxide and chlorine react to form ferric chloride. Since the Joule heat device can accurately control the temperature and heat quickly, the chloride is instantly vaporized into gas; at the second stage temperature, other metal oxides react with chlorine to varying degrees to form chlorides, but since the vaporization temperature is not higher than the boiling point, only aluminum chloride and a small amount of ferrous chloride are vaporized to form gas; at the third stage temperature, nickel chloride is vaporized, at the fourth stage temperature, cobalt chloride is vaporized, at the fifth stage temperature, manganese chloride is vaporized, and at the sixth stage temperature, lithium chloride is vaporized, thereby achieving staged purification of metals.

[0013] The desublimation temperature is set as follows: the first stage chlorination desublimation temperature is 200-300°C, the second stage chlorination desublimation temperature is 50-150°C, the third stage desublimation temperature is 800-900°C, the fourth stage desublimation temperature is 680-700°C, the fifth stage desublimation temperature is 620-650°C, and the sixth stage desublimation temperature is 500-600°C.

[0014] In the first stage of desublimation, ferric chloride desublimates to form solid ferric chloride, in the second stage of desublimation, aluminum chloride and a small amount of ferrous chloride desublimate to form a solid state, in the third stage of desublimation, nickel chloride desublimates to form a solid state, in the fourth stage of desublimation, cobalt chloride gas desublimates to form a solid state, in the fifth stage of desublimation, manganese chloride desublimates to form a solid state, and in the sixth stage of desublimation, lithium chloride desublimates to form a solid state.

[0015] Furthermore, the carrier of the Joule heat device is a graphite boat or carbon paper.

[0016] Furthermore, the chlorine atmosphere is a mixed gas with a volume ratio of chlorine to nitrogen of 2-3:1.

[0017] Furthermore, in step 4, the solid is added into deionized water at a mass fraction of 20-30%.

[0018] Furthermore, in step 4, the molar concentration of the sodium carbonate aqueous solution is 2-3 mol / L.

[0019] Furthermore, in step four, the pH of the solid reaction after coagulation in the first stage is adjusted to 3.5-4.0, the pH of the solid reaction after coagulation in the second stage is first adjusted to 3.5-4.0, and then the pH is adjusted to 6.0-7.5 after filtering the precipitate, the pH of the solid reaction after coagulation in the third stage is adjusted to 8.0-8.5, the pH of the solid reaction after coagulation in the fourth stage is adjusted to 7.0-9.0, the pH of the solid reaction after coagulation in the fifth stage is adjusted to 9.0-10.0, and the pH of the solid reaction after coagulation in the sixth stage is adjusted to 8.5-9.5.

[0020] The product formed by the reaction of metal chloride and sodium carbonate needs to be completely precipitated within a certain pH range. In the second stage, ferrous chloride and aluminum chloride react with sodium carbonate to generate ferric hydroxide and aluminum hydroxide respectively. The pH is first adjusted to 3.5-4.0 to achieve precipitation of ferric hydroxide, and then the pH is adjusted to 6.0-7.5 after filtration to achieve precipitation of aluminum hydroxide.

[0021] Beneficial effects of the present invention: (1) The present invention uses a Joule heat device to carry out the chlorination roasting reaction of the positive electrode material of the lithium battery. Based on the characteristics of Joule heat that can heat quickly and accurately control the temperature, combined with the difference in the chlorination reaction temperature of different metal oxides and the gasification temperature of the chlorination product, a staged gasification and desublimation treatment is achieved to obtain different metal chlorides, which are accurately and efficiently purified.

[0022] (2) Through Joule heat treatment and staged desublimation, different positive electrode materials can be centrally recovered and processed, and different metal chlorides can be obtained. Since the purity of each metal chloride is relatively high, the use of sodium carbonate aqueous solution as a precipitant during the secondary precipitation treatment can achieve efficient precipitation and impurity removal, reducing the corrosive pollution caused by the use of strong alkali. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1 Step 1: calcining the positive electrode of the lithium iron phosphate battery at 700° C. for 3 h to remove organic matter, and peeling off the aluminum foil to obtain electrode material powder; Step 2: Place the electrode material powder on a graphite boat carrier of a Joule heat device and perform thermal shock treatment under a chlorine atmosphere (the volume ratio of chlorine to nitrogen is 2:1). The treatment process is divided into stages of temperature increase and chlorination. The temperature of the first stage is 380°C and the temperature is kept constant for 10s. The temperature of the second stage is 900°C and the temperature is kept constant for 30s. The temperature of the third stage is 1400°C and the temperature is kept constant for 10s. The heating rate of the thermal shock treatment is 10 3 °C / s; Step 3: Desubliming the gas produced after the three stages of chlorination, the desublimation temperature of the first stage of chlorination is 300°C, the desublimation temperature of the second stage of chlorination is 150°C, and the desublimation temperature of the third stage is 500°C; Step 4, the solid after desublimation in each stage is added to deionized water at a mass fraction of 30%, and a sodium carbonate aqueous solution with a molar concentration of 3 mol / L is added after mixing. In the solid reaction after desublimation in the first stage, the pH is adjusted to 3.5-4.0, and the precipitate is collected after precipitation is complete, washed with deionized water and dried to obtain an iron hydroxide product. In the solid reaction after desublimation in the second stage, the pH is first adjusted to 3.5-4.0, and the precipitate is collected after precipitation is complete, washed with deionized water and dried to obtain an iron hydroxide product, and then the pH of the filtrate is adjusted to 6.0-7.5, and the precipitate is collected after precipitation is complete, washed with deionized water and dried to obtain an aluminum hydroxide product. In the solid reaction after desublimation in the third stage, the pH is adjusted to 8.5-9.5, and the precipitate is collected after precipitation is complete, and washed with deionized water and dried to obtain a lithium carbonate product.

[0025] Among them, the recovery rate of metallic iron is 98.4%, and the recovery rate of metallic lithium is 97.9%.

[0026] Example 2 The difference from Example 1 is that the processed materials include lithium cobalt oxide and lithium manganese iron phosphate battery positive electrode sheets, and the specific steps are as follows: Step 1: calcining the positive electrode sheets of lithium cobalt oxide and lithium manganese iron phosphate batteries at 680° C. for 5 h to remove organic matter, and peeling off the aluminum foil to obtain electrode material powder; Step 2: Place the electrode material powder on a graphite boat carrier of a Joule heat device, and perform thermal shock treatment under a chlorine atmosphere (the volume ratio of chlorine to nitrogen is 2.5:1). The treatment process is divided into stages of temperature increase and chlorination. The temperature of the first stage is 380°C, constant temperature for 10s, the temperature of the second stage is 900°C, constant temperature for 30s, the temperature of the third stage is 1150°C, constant temperature for 10s, the temperature of the fourth stage is 1280°C, constant temperature for 10s, and the temperature of the fifth stage is 1400°C, constant temperature for 10s. The heating rate of the thermal shock treatment is 10 3 °C / s; Step 3, condensing the gas generated after the five stages of chlorination, the chlorination condensation temperature of the first stage is 300°C, the chlorination condensation temperature of the second stage is 150°C, the condensation temperature of the third stage is 700°C, the condensation temperature of the fourth stage is 620°C, and the condensation temperature of the fifth stage is 500°C; Step 4, the solid after desublimation in each stage is added to deionized water according to a mass fraction of 30%, and a sodium carbonate aqueous solution with a molar concentration of 3 mol / L is added after mixing. The pH of the solid reaction after desublimation in the first stage is adjusted to 3.5-4.0, and the precipitate is collected after precipitation is complete, washed with deionized water and dried to obtain an iron hydroxide product. The pH of the solid reaction after desublimation in the second stage is first adjusted to 3.5-4.0, and the precipitate is collected after precipitation is complete. The precipitate is washed with deionized water and dried to obtain an iron hydroxide product, and then the pH of the filtrate is adjusted to 6.0-7.5. After precipitation is complete, the precipitate is collected, and the aluminum hydroxide product is washed and dried. The pH of the solid reaction after desublimation in the third stage is adjusted to 7.0-9.0, and the precipitate is collected after precipitation is complete. The cobalt carbonate product is washed and dried with deionized water. The pH of the solid reaction after desublimation in the fourth stage is adjusted to 9.0-10.0, and the precipitate is collected after precipitation is complete. The manganese carbonate product is washed and dried with deionized water. The pH of the solid reaction after desublimation in the fifth stage is adjusted to 8.5-9.5, and the precipitate is collected after precipitation is complete. The lithium carbonate product is washed and dried.

[0027] Among them, the recovery rate of metallic iron is 98.2%, the recovery rate of metallic cobalt is 95.5%, the recovery rate of metallic manganese is 96.1%, and the recovery rate of metallic lithium is 97.4%.

[0028] Example 3 The difference from Example 1 is that the processed materials include lithium nickel cobalt manganese oxide and lithium manganese iron phosphate battery positive electrode sheets, and the specific steps are as follows: Step 1: calcining the positive electrode sheets of lithium nickel cobalt manganese oxide and lithium manganese iron phosphate batteries at 650° C. for 6 hours to remove organic matter, and peeling off the aluminum foil to obtain electrode material powder; Step 2: Place the electrode material powder on a carbon paper carrier of a Joule heat device, and perform thermal shock treatment under a chlorine atmosphere (the volume ratio of chlorine to nitrogen is 3:1). The treatment process is divided into stages of temperature increase and chlorination. The temperature of the first stage is 380°C, constant temperature for 10s, the temperature of the second stage is 900°C, constant temperature for 30s, the temperature of the third stage is 1000°C, constant temperature for 10s, the temperature of the fourth stage is 1150°C, constant temperature for 10s, the temperature of the fifth stage is 1280°C, constant temperature for 10s, the temperature of the sixth stage is 1400°C, constant temperature for 10s, and the heating rate of the thermal shock treatment is 10 3 °C / s; Step 3, condensing the gas generated after the six stages of chlorination, the chlorination condensation temperature of the first stage is 300°C, the chlorination condensation temperature of the second stage is 150°C, the condensation temperature of the third stage is 900°C, the condensation temperature of the fourth stage is 700°C, the condensation temperature of the fifth stage is 620°C, and the condensation temperature of the sixth stage is 500°C; Step 4: adding the solid after desublimation in each stage to deionized water at a mass fraction of 30%, adding a sodium carbonate aqueous solution with a molar concentration of 3 mol / L after mixing, adjusting the pH to 3.5-4.0 in the solid reaction after desublimation in the first stage, collecting the precipitate after complete precipitation, washing with deionized water and drying to obtain an iron hydroxide product, first adjusting the pH to 3.5-4.0 in the solid reaction after desublimation in the second stage, collecting the precipitate after complete precipitation, washing with deionized water and drying to obtain an iron hydroxide product, and then adjusting the pH of the filtrate to 6.0-7.5, collecting the precipitate after complete precipitation, washing with deionized water and drying to obtain an aluminum hydroxide product, and the third In the solid reaction after the first stage of desublimation, the pH is adjusted to 8.0-8.5, and the precipitate is collected after the precipitation is complete, washed with deionized water and dried to obtain a nickel carbonate product. In the solid reaction after the fourth stage of desublimation, the pH is adjusted to 7.0-9.0, and the precipitate is collected after the precipitation is complete, washed with deionized water and dried to obtain a cobalt carbonate product. In the solid reaction after the fifth stage of desublimation, the pH is adjusted to 9.0-10.0, and the precipitate is collected after the precipitation is complete, washed with deionized water and dried to obtain a manganese carbonate product. In the solid reaction after the sixth stage of desublimation, the pH is adjusted to 8.5-9.5, and the precipitate is collected after the precipitation is complete, washed with deionized water and dried to obtain a lithium carbonate product.

[0029] Among them, the recovery rate of metallic iron was 98.3%, the recovery rate of metallic nickel was 96.6%, the recovery rate of metallic cobalt was 95.1%, the recovery rate of metallic manganese was 95.9%, and the recovery rate of metallic lithium was 97.0%.

[0030] Example 4 The difference from Example 3 is that the temperature of each stage of the thermal shock treatment in step 2 is reduced and the constant temperature time is extended. The specific steps are as follows: Step 1: calcining the positive electrode sheets of lithium nickel cobalt manganese oxide and lithium manganese iron phosphate batteries at 650° C. for 6 hours to remove organic matter, and peeling off the aluminum foil to obtain electrode material powder; Step 2: Place the electrode material powder on a carbon paper carrier of a Joule heat device, and perform thermal shock treatment under a chlorine atmosphere (the volume ratio of chlorine to nitrogen is 3:1). The treatment process is divided into stages of temperature increase and chlorination. The temperature of the first stage is 370°C, constant temperature for 15s, the temperature of the second stage is 800°C, constant temperature for 40s, the temperature of the third stage is 990°C, constant temperature for 15s, the temperature of the fourth stage is 1100°C, constant temperature for 15s, the temperature of the fifth stage is 1250°C, constant temperature for 15s, the temperature of the sixth stage is 1370°C, constant temperature for 15s, and the heating rate of the thermal shock treatment is 10 3°C / s; Step 3, condensing the gas generated after the six stages of chlorination, the chlorination condensation temperature of the first stage is 300°C, the chlorination condensation temperature of the second stage is 150°C, the condensation temperature of the third stage is 900°C, the condensation temperature of the fourth stage is 700°C, the condensation temperature of the fifth stage is 620°C, and the condensation temperature of the sixth stage is 500°C; Step 4: adding the solid after desublimation in each stage to deionized water at a mass fraction of 30%, adding a sodium carbonate aqueous solution with a molar concentration of 3 mol / L after mixing, adjusting the pH to 3.5-4.0 in the solid reaction after desublimation in the first stage, collecting the precipitate after complete precipitation, washing with deionized water and drying to obtain an iron hydroxide product, first adjusting the pH to 3.5-4.0 in the solid reaction after desublimation in the second stage, collecting the precipitate after complete precipitation, washing with deionized water and drying to obtain an iron hydroxide product, and then adjusting the pH of the filtrate to 6.0-7.5, collecting the precipitate after complete precipitation, washing with deionized water and drying to obtain an aluminum hydroxide product, and the third In the solid reaction after the first stage of desublimation, the pH is adjusted to 8.0-8.5, and the precipitate is collected after the precipitation is complete, washed with deionized water and dried to obtain a nickel carbonate product. In the solid reaction after the fourth stage of desublimation, the pH is adjusted to 7.0-9.0, and the precipitate is collected after the precipitation is complete, washed with deionized water and dried to obtain a cobalt carbonate product. In the solid reaction after the fifth stage of desublimation, the pH is adjusted to 9.0-10.0, and the precipitate is collected after the precipitation is complete, washed with deionized water and dried to obtain a manganese carbonate product. In the solid reaction after the sixth stage of desublimation, the pH is adjusted to 8.5-9.5, and the precipitate is collected after the precipitation is complete, washed with deionized water and dried to obtain a lithium carbonate product.

[0031] Among them, the recovery rate of metallic iron is 98.7%, the recovery rate of metallic nickel is 97.5%, the recovery rate of metallic cobalt is 96.8%, the recovery rate of metallic manganese is 97.0%, and the recovery rate of metallic lithium is 98.2%.

[0032] Example 5 The difference from Example 4 is that the temperature of each stage of the thermal shock treatment in step 2 is reduced and the constant temperature time is extended. The specific steps are as follows: Step 1: calcining the positive electrode sheets of lithium nickel cobalt manganese oxide and lithium manganese iron phosphate batteries at 650° C. for 6 hours to remove organic matter, and peeling off the aluminum foil to obtain electrode material powder; Step 2: Place the electrode material powder on a carbon paper carrier of a Joule heat device, and perform thermal shock treatment under a chlorine atmosphere (the volume ratio of chlorine to nitrogen is 3:1). The treatment process is divided into stages of temperature increase and chlorination. The temperature of the first stage is 350°C, constant temperature for 20s, the temperature of the second stage is 700°C, constant temperature for 50s, the temperature of the third stage is 980°C, constant temperature for 20s, the temperature of the fourth stage is 1050°C, constant temperature for 20s, the temperature of the fifth stage is 1200°C, constant temperature for 20s, the temperature of the sixth stage is 1350°C, constant temperature for 20s, and the heating rate of the thermal shock treatment is 10 3 °C / s; Step 3, condensing the gas generated after the six stages of chlorination, the chlorination condensation temperature of the first stage is 300°C, the chlorination condensation temperature of the second stage is 150°C, the condensation temperature of the third stage is 900°C, the condensation temperature of the fourth stage is 700°C, the condensation temperature of the fifth stage is 620°C, and the condensation temperature of the sixth stage is 500°C; Step 4: adding the solid after desublimation in each stage to deionized water at a mass fraction of 30%, adding a sodium carbonate aqueous solution with a molar concentration of 3 mol / L after mixing, adjusting the pH to 3.5-4.0 in the solid reaction after desublimation in the first stage, collecting the precipitate after complete precipitation, washing with deionized water and drying to obtain an iron hydroxide product, first adjusting the pH to 3.5-4.0 in the solid reaction after desublimation in the second stage, collecting the precipitate after complete precipitation, washing with deionized water and drying to obtain an iron hydroxide product, and then adjusting the pH of the filtrate to 6.0-7.5, collecting the precipitate after complete precipitation, washing with deionized water and drying to obtain an aluminum hydroxide product, and the third In the solid reaction after the first stage of desublimation, the pH is adjusted to 8.0-8.5, and the precipitate is collected after the precipitation is complete, washed with deionized water and dried to obtain a nickel carbonate product. In the solid reaction after the fourth stage of desublimation, the pH is adjusted to 7.0-9.0, and the precipitate is collected after the precipitation is complete, washed with deionized water and dried to obtain a cobalt carbonate product. In the solid reaction after the fifth stage of desublimation, the pH is adjusted to 9.0-10.0, and the precipitate is collected after the precipitation is complete, washed with deionized water and dried to obtain a manganese carbonate product. In the solid reaction after the sixth stage of desublimation, the pH is adjusted to 8.5-9.5, and the precipitate is collected after the precipitation is complete, washed with deionized water and dried to obtain a lithium carbonate product.

[0033] Among them, the recovery rate of metallic iron is 97.3%, the recovery rate of metallic nickel is 95.0%, the recovery rate of metallic cobalt is 93.9%, the recovery rate of metallic manganese is 94.6%, and the recovery rate of metallic lithium is 95.5%.

[0034] Comparative Example 1 Compared with Example 1, a conventional heating method is used for treatment, wherein the heating device is replaced by a tubular furnace instead of a Joule heat device, the carrier is replaced by a crucible, and the heating time is prolonged. The specific steps are as follows: Step 1: calcining the positive electrode of the lithium iron phosphate battery at 700° C. for 3 h to remove organic matter, and peeling off the aluminum foil to obtain electrode material powder; Step 2: Place the electrode material powder on a crucible in a tube furnace and heat and calcine it in a chlorine atmosphere (the volume ratio of chlorine to nitrogen is 2:1). The treatment process is divided into stages of temperature increase and chlorination. The temperature of the first stage is 380°C and the temperature is kept constant for 20 minutes. The temperature of the second stage is 900°C and the temperature is kept constant for 30 minutes. The temperature of the third stage is 1400°C and the temperature is kept constant for 20 minutes. The heating rate of the heating and calcination treatment is 100°C / min. Step 3: Desubliming the gas produced after the three stages of chlorination, the desublimation temperature of the first stage of chlorination is 300°C, the desublimation temperature of the second stage of chlorination is 150°C, and the desublimation temperature of the third stage is 500°C; Step 4, the solid after desublimation in each stage is added to deionized water at a mass fraction of 30%, and a sodium carbonate aqueous solution with a molar concentration of 3 mol / L is added after mixing. In the solid reaction after desublimation in the first stage, the pH is adjusted to 3.5-4.0, and the precipitate is collected after precipitation is complete, washed with deionized water and dried to obtain an iron hydroxide product. In the solid reaction after desublimation in the second stage, the pH is first adjusted to 3.5-4.0, and the precipitate is collected after precipitation is complete, washed with deionized water and dried to obtain an iron hydroxide product, and then the pH of the filtrate is adjusted to 6.0-7.5, and the precipitate is collected after precipitation is complete, washed with deionized water and dried to obtain an aluminum hydroxide product. In the solid reaction after desublimation in the third stage, the pH is adjusted to 8.5-9.5, and the precipitate is collected after precipitation is complete, and washed with deionized water and dried to obtain a lithium carbonate product.

[0035] Among them, the recovery rate of metallic iron was 86.5%, and the recovery rate of metallic lithium was 92.3%.

[0036] Combining Examples 1 to 3, it can be seen that by adjusting the treatment temperature of each stage of the thermal shock treatment according to the type of metal elements contained in the treated electrode sheet, efficient purification of metal elements in the positive electrode material of the lithium battery can be achieved, and compared with the traditional wet treatment, the pollution hazard of the waste liquid is reduced; Examples 4 and 5 reduce the temperature of the thermal shock treatment on the basis of Example 3 and extend the treatment time, among which, the recovery rate is the highest under the treatment conditions of Example 4. Combining the recovery rate results of Example 1 and Comparative Example 1, it can be seen that the chlorination reaction is insufficient in Comparative Example 1 due to the inability to achieve rapid and uniform heating under the conventional heating method, and because there is a significant difference in the temperature of the heated substance from the outside to the inside when the traditional heating method is used, the chlorination temperature cannot be accurately controlled, the gas component formed by the chlorination reaction is impure, and the recovery rate is reduced.

[0037] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" 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.

[0038] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for extracting and recovering metal elements in lithium batteries using a chlorination method, characterized in that: The following steps are involved: Step 1: calcining the positive electrode sheet of the lithium battery to remove organic matter, and peeling off the aluminum foil to obtain electrode material powder; Step 2: placing the electrode material powder on a carrier of a Joule heat device and subjecting it to a thermal shock treatment in a chlorine atmosphere, wherein the treatment process is carried out by heating and chlorination in stages, and the temperature range is 350-1400°C; Step 3: condense the gas produced after chlorination at each stage, and the condensation temperature is 50-970°C; Step 4: Add the solids after desublimation in each stage into deionized water, add sodium carbonate aqueous solution after mixing, adjust the pH to 3.5-10.0, and complete the precipitation reaction. Collect the precipitate, wash and dry to obtain the metal salt product; The active component of the lithium battery positive electrode plate is at least one of lithium iron phosphate, lithium cobalt oxide, lithium iron manganese phosphate, and lithium nickel cobalt manganese oxide; In step 1, the calcination temperature is 650-700°C and the calcination time is 3-6h; The staged heating chlorination temperature of the thermal shock treatment is controlled as follows: the temperature of the first stage is 350-380°C, constant temperature for 10-20s, the temperature of the second stage is 700-900°C, constant temperature for 30-50s, the temperature of the third stage is 980-1000°C, constant temperature for 10-20s, the temperature of the fourth stage is 1050-1150°C, constant temperature for 10-20s, the temperature of the fifth stage is 1200-1280°C, constant temperature for 10-20s, the temperature of the sixth stage is 1350-1400°C, constant temperature for 10-20s, and the heating rate of the thermal shock treatment is 103°C / s; The desublimation temperature is set as follows: the first stage chlorination desublimation temperature is 200-300°C, the second stage chlorination desublimation temperature is 50-150°C, the third stage desublimation temperature is 800-900°C, the fourth stage desublimation temperature is 680-700°C, the fifth stage desublimation temperature is 620-650°C, and the sixth stage desublimation temperature is 500-600°C.

2. The method for extracting and recovering metal elements in lithium batteries using chlorination method according to claim 1, characterized in that: The carrier of the Joule heat device is a graphite boat or carbon paper.

3. The method for extracting and recovering metal elements in lithium batteries using chlorination method according to claim 1, characterized in that: The chlorine atmosphere is a mixed gas with a volume ratio of chlorine to nitrogen of 2-3:

1.

4. The method for extracting and recovering metal elements in lithium batteries using chlorination method according to claim 1, characterized in that: In step 4, the solid is added into deionized water at a mass fraction of 20-30%.

5. The method for extracting and recovering metal elements in lithium batteries using chlorination method according to claim 1, characterized in that: In step 4, the molar concentration of the sodium carbonate aqueous solution is 2-3 mol / L.

6. The method for extracting and recovering metal elements in lithium batteries using chlorination method according to claim 1, characterized in that: In step 4, the pH of the solid reaction after coagulation in the first stage is adjusted to 3.5-4.0, the pH of the solid reaction after coagulation in the second stage is first adjusted to 3.5-4.0, and then the pH is adjusted to 6.0-7.5 after filtering the precipitate, the pH of the solid reaction after coagulation in the third stage is adjusted to 8.0-8.5, the pH of the solid reaction after coagulation in the fourth stage is adjusted to 7.0-9.0, the pH of the solid reaction after coagulation in the fifth stage is adjusted to 9.0-10.0, and the pH of the solid reaction after coagulation in the sixth stage is adjusted to 8.5-9.5.