Method for deeply cleaning anode powder of waste spinel lithium manganate battery by high-energy electromagnetic waves

Abstract

The invention relates to the field of resource utilization of lithium ion batteries, in particular to a method for deeply cleaning waste spinel lithium manganate battery positive electrode powder through high-energy electromagnetic waves. The method comprises the following steps: discharging, disassembling, crushing and powdering a waste spinel lithium manganate battery to obtain the waste spinel lithium manganate positive electrode powder; the spinel lithium manganate positive electrode powder is ionized by high-energy electromagnetic waves, and the ionized spinel lithium manganate positive electrode powder has extremely high chemical activity and can react with water molecules at normal temperature to generate hydroxyl free radicals. OH and atomic hydrogen H; organic matters in the spinel lithium manganate positive electrode powder are converted into harmless CO2 and H2O under the action of the atomic hydrogen H and the hydroxyl radical. OH.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery resource utilization, specifically a method for deep cleaning of waste spinel manganese lithium battery cathode powder using high-energy electromagnetic waves. Background Technology

[0002] Since their commercialization in the late 20th century, lithium-ion batteries have been widely used in portable electronic devices such as mobile phones, laptops, and cameras, as well as electric vehicles, due to their numerous advantages, including high energy density, light weight, long lifespan, and lack of memory effect. With the rapid growth in demand for lithium-ion batteries, a large number of discarded batteries are inevitably generated.

[0003] Because lithium-ion battery cathode powder contains a large amount of precious metals, its recycling has become a key focus and hot topic in the recycling of waste lithium-ion batteries. The recycling of lithium-ion battery cathode powder mostly employs a wet process: first, the cathode powder is dissolved in acid (sulfuric acid, hydrochloric acid, or nitric acid) and hydrogen peroxide, then precious metal ions in the solution are precipitated with an alkali, ultimately yielding a precious metal precipitate and a lithium-containing solution.

[0004] However, in waste lithium-ion batteries, the cathode powder contains approximately 88% positive electrode active material, 7%–8% acetylene black conductive agent, and 3%–4% organic binder (mainly polyvinylidene fluoride and polytetrafluoroethylene), as well as a small amount of carbonate organic solvents (derived from the electrolyte). The presence of organic matter in the cathode powder of waste lithium-ion batteries seriously affects the effectiveness of the wet recycling process: on the one hand, organic matter consumes a large amount of hydrogen peroxide, resulting in the actual amount of hydrogen peroxide used being far higher than the theoretical amount; on the other hand, organic solvents also enter the lithium-containing solution and generate a large amount of organic wastewater, leading to serious environmental pollution problems. Summary of the Invention

[0005] The purpose of this invention is to provide a deep cleaning method for waste spinel manganese lithium battery cathode powder, which reduces the reagent cost of subsequent wet recycling processes and avoids the generation of organic wastewater by decomposing the organic matter in the cathode powder.

[0006] The technical solution of the present invention is as follows:

[0007] (1) The waste spinel manganese lithium battery is placed in iron powder for short-circuit discharge, and the electrical energy in the waste battery will eventually be converted into recyclable thermal energy.

[0008] (2) Disassemble the spinel lithium manganese oxide battery after discharge and remove the positive electrode sheet; place the positive electrode sheet in a vibrating screen to separate the spinel lithium manganese oxide positive electrode material and aluminum foil, and the aluminum foil can be sold directly as a product; crush and grind the spinel lithium manganese oxide positive electrode material to obtain spinel lithium manganese oxide positive electrode powder containing impurities (acetylene black, binder and organic solvent).

[0009] (3) The above-mentioned spinel lithium manganese oxide cathode powder is placed in a fluidized bed reaction chamber, and air is used as the working gas to make the spinel lithium manganese oxide cathode powder fluidized; electromagnetic treatment of the spinel lithium manganese oxide cathode powder inside the fluidized bed reaction chamber is performed with electromagnetic waves of 19570-19670MHz until the cathode powder shows a weak electric spark; LiMn2O4 in the spinel lithium manganese oxide cathode powder undergoes physical ionization under the action of high-energy electromagnetic waves to generate LiMn2O4. + and e - .

[0010] (4) According to the LiMn2O4 / H2O ratio of 76.6 to 77.6 (mass ratio), water vapor at 355 to 365°C is injected into the fluidized bed reaction chamber; water molecules in LiMn2O4 + and e - Under the action of the strong oxidant hydroxyl radical ·OH, hydroxyl radical ·OH and atomic hydrogen H are generated. Atomic hydrogen H has a strong reducing ability and can decompose and reduce the organic binder (mainly polyvinylidene fluoride and polytetrafluoroethylene) and organic solvent (carbonate) in the spinel lithium manganese oxide cathode powder into small molecule organic matter. The above small molecule organic matter is oxidized into CO2 and H2O under the action of the strong oxidant hydroxyl radical ·OH. The acetylene black in the spinel lithium manganese oxide cathode powder enters the air, resulting in clean spinel lithium manganese oxide cathode powder.

[0011] (5) The exhaust gas from the fluidized bed reactor is introduced into a cyclone dust collector for deep dust removal, and finally product-grade acetylene black is obtained. The acetylene black can be reused in the production of spinel manganese lithium oxide battery cathode materials.

[0012] Among them, the conditions for physical ionization of spinel lithium manganese oxide cathode powder are extremely stringent, requiring strict control of the electromagnetic wave frequency between 19570 and 19670 MHz.

[0013] The ionization equation for spinel lithium manganese oxide cathode powder is LiMn2O4=LiMn2O4 + +e - .

[0014] Among them, the ionized spinel lithium manganese oxide powder has extremely strong chemical activity, and water molecules can undergo redox reactions with it at room temperature.

[0015] Among them: LiMn2O4+ +H₂O=LiMn₂O₄ + ·OH+H + and e - +H₂O=H + OH⁻ - These are the reaction equations for generating hydroxyl radicals (·OH) and atomic hydrogen (H), respectively.

[0016] Among them, the redox potential of hydroxyl radicals can reach 2.8V, making it an oxidizing agent with oxidizing power second only to fluorine.

[0017] The beneficial effects of this invention are: it provides a novel method for preparing hydroxyl radicals (·OH); the process is green and environmentally friendly, with no secondary pollutants generated; it can completely decompose the organic binders and organic solvents in waste spinel lithium manganese oxide cathode powder into harmless CO2 and H2O, and recover the aluminum foil and acetylene black conductive agent; it can also reduce the reagent cost of hydrogen peroxide in the subsequent wet recycling process; and it avoids the generation of organic wastewater in the subsequent wet recycling process. Detailed Implementation

[0018] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but this is not intended to limit the present invention.

[0019] Example 1:

[0020] (1) The waste spinel manganese lithium battery is placed in iron powder for short-circuit discharge, and the electrical energy in the waste battery will eventually be converted into recyclable thermal energy.

[0021] (2) Disassemble the spinel lithium manganese oxide battery after discharge and remove the positive electrode sheet; place the positive electrode sheet in a vibrating screen to separate the spinel lithium manganese oxide positive electrode material and aluminum foil, and the aluminum foil can be sold directly as a product; crush and grind the spinel lithium manganese oxide positive electrode material to obtain spinel lithium manganese oxide positive electrode powder containing impurities (acetylene black, binder and organic solvent).

[0022] (3) The above-mentioned spinel lithium manganese oxide cathode powder was placed in a fluidized bed reaction chamber, and air was used as the working gas to make the spinel lithium manganese oxide cathode powder fluidized. The spinel lithium manganese oxide cathode powder inside the fluidized bed reaction chamber was subjected to electromagnetic treatment with 19570MHz electromagnetic waves until the cathode powder showed a weak electric spark. Under the action of high-energy electromagnetic waves, LiMn2O4 in the spinel lithium manganese oxide cathode powder was physically ionized to generate LiMn2O4. + and e - .

[0023] (4) Water vapor at 365℃ is injected into the fluidized bed reaction chamber at a mass ratio of LiMn2O4 / H2O = 77.6; water molecules in LiMn2O4+ and e - Under the action of the strong oxidant hydroxyl radical ·OH, hydroxyl radical ·OH and atomic hydrogen H are generated. Atomic hydrogen H has a strong reducing ability and can decompose and reduce the organic binder (mainly polyvinylidene fluoride and polytetrafluoroethylene) and organic solvent (carbonate) in the spinel lithium manganese oxide cathode powder into small molecule organic matter. The above small molecule organic matter is oxidized into CO2 and H2O under the action of the strong oxidant hydroxyl radical ·OH. The acetylene black in the spinel lithium manganese oxide cathode powder enters the air, resulting in clean spinel lithium manganese oxide cathode powder.

[0024] (5) The exhaust gas from the fluidized bed reactor is introduced into a cyclone dust collector for deep dust removal, and finally product-grade acetylene black is obtained. The acetylene black can be reused in the production of spinel manganese lithium oxide battery cathode materials.

[0025] Example 2:

[0026] (1) The waste spinel manganese lithium battery is placed in iron powder for short-circuit discharge, and the electrical energy in the waste battery will eventually be converted into recyclable thermal energy.

[0027] (2) Disassemble the spinel lithium manganese oxide battery after discharge and remove the positive electrode sheet; place the positive electrode sheet in a vibrating screen to separate the spinel lithium manganese oxide positive electrode material and aluminum foil, and the aluminum foil can be sold directly as a product; crush and grind the spinel lithium manganese oxide positive electrode material to obtain spinel lithium manganese oxide positive electrode powder containing impurities (acetylene black, binder and organic solvent).

[0028] (3) The above-mentioned spinel lithium manganese oxide cathode powder was placed in a fluidized bed reaction chamber, and air was used as the working gas to make the spinel lithium manganese oxide cathode powder fluidized. Electromagnetic treatment was performed on the spinel lithium manganese oxide cathode powder inside the fluidized bed reaction chamber with 19670MHz electromagnetic waves until the cathode powder showed a weak electric spark. Under the action of high-energy electromagnetic waves, LiMn2O4 in the spinel lithium manganese oxide cathode powder was physically ionized to generate LiMn2O4. + and e - .

[0029] (4) Water vapor at 355℃ is injected into the fluidized bed reaction chamber at a mass ratio of LiMn2O4 / H2O = 76.6; water molecules in LiMn2O4 + and e -Under the action of the strong oxidant hydroxyl radical ·OH, hydroxyl radical ·OH and atomic hydrogen H are generated. Atomic hydrogen H has a strong reducing ability and can decompose and reduce the organic binder (mainly polyvinylidene fluoride and polytetrafluoroethylene) and organic solvent (carbonate) in the spinel lithium manganese oxide cathode powder into small molecule organic matter. The above small molecule organic matter is oxidized into CO2 and H2O under the action of the strong oxidant hydroxyl radical ·OH. The acetylene black in the spinel lithium manganese oxide cathode powder enters the air, resulting in clean spinel lithium manganese oxide cathode powder.

[0030] (5) The exhaust gas from the fluidized bed reactor is introduced into a cyclone dust collector for deep dust removal, and finally product-grade acetylene black is obtained. The acetylene black can be reused in the production of spinel manganese lithium oxide battery cathode materials.

Claims

1. This invention provides a method for deep cleaning of waste spinel manganese lithium battery cathode powder using high-energy electromagnetic waves, characterized in that: (1) The waste spinel manganese lithium battery is placed in iron powder for short-circuit discharge, and the electrical energy in the waste battery will eventually be converted into recyclable thermal energy. (2) Disassemble the spinel lithium manganese oxide battery after discharge and remove the positive electrode sheet; place the positive electrode sheet in a vibrating screen to separate the spinel lithium manganese oxide positive electrode material and aluminum foil, and the aluminum foil can be sold directly as a product; crush and grind the spinel lithium manganese oxide positive electrode material to obtain spinel lithium manganese oxide positive electrode powder containing impurities (acetylene black, binder and organic solvent). (3) the spinel lithium manganate positive electrode powder is placed in a fluidized bed reaction chamber, air is used as working gas to make the spinel lithium manganate positive electrode powder in a fluidized state; electromagnetic wave with a frequency of 19570-19670MHz is used to treat the spinel lithium manganate positive electrode powder in the fluidized bed reaction chamber until weak electric spark appears; LiMn2O4 in the spinel lithium manganate positive electrode powder is physically ionized to generate LiMn2O4 + and e - . (4) According to the LiMn2O4 / H2O ratio of 76.6 to 77.6 (mass ratio), water vapor at 355 to 365°C is injected into the fluidized bed reaction chamber; water molecules in LiMn2O4 + and e - Under the action of the strong oxidant hydroxyl radical ·OH, hydroxyl radical ·OH and atomic hydrogen H are generated. Atomic hydrogen H has a strong reducing ability and can decompose and reduce the organic binder (mainly polyvinylidene fluoride and polytetrafluoroethylene) and organic solvent (carbonate) in the spinel lithium manganese oxide cathode powder into small molecule organic matter. The above small molecule organic matter is oxidized into CO2 and H2O under the action of the strong oxidant hydroxyl radical ·OH. The acetylene black in the spinel lithium manganese oxide cathode powder enters the air, resulting in clean spinel lithium manganese oxide cathode powder. (5) The exhaust gas from the fluidized bed reactor is introduced into a cyclone dust collector for deep dust removal, and finally product-grade acetylene black is obtained. The acetylene black can be reused in the production of spinel manganese lithium oxide battery cathode materials.

2. The method for deep cleaning of waste spinel manganese lithium battery cathode powder using high-energy electromagnetic waves according to claim 1, characterized in that: The conditions for physical ionization of spinel lithium manganese oxide cathode powder are extremely stringent, requiring strict control of the electromagnetic wave frequency between 19570 and 19670 MHz.

3. The method for deep cleaning of waste spinel manganese lithium battery cathode powder using high-energy electromagnetic waves according to claim 1, characterized in that: LiMn2O4=LiMn2O4 + +e - The ionization equation is for spinel lithium manganese oxide cathode powder.

4. The method for deep cleaning of waste spinel lithium manganese oxide battery cathode powder using high-energy electromagnetic waves according to claim 1, characterized in that: The ionized spinel lithium manganese oxide powder has extremely strong chemical activity, and water molecules can undergo redox reactions with it at room temperature.

5. The method for deep cleaning of waste spinel manganese lithium battery cathode powder using high-energy electromagnetic waves according to claim 1, characterized in that: LiMn2O4 + +H₂O=LiMn₂O₄+·OH⁺ ... + and e - +H₂O=H + OH⁻ - These are the reaction equations for generating hydroxyl radicals (·OH) and atomic hydrogen (H), respectively.

6. The method for deep cleaning of waste spinel lithium manganese oxide battery cathode powder using high-energy electromagnetic waves according to claim 1, characterized in that: The redox potential of hydroxyl radicals can reach 2.8V, making them the second most powerful oxidizing agent after fluorine.