Method for deeply cleaning positive electrode powder of waste lithium nickel cobalt aluminate battery through 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 nickel cobalt lithium aluminate battery positive electrode powder through high-energy electromagnetic waves. The method comprises the following steps: discharging, disassembling, crushing and powdering waste nickel cobalt lithium aluminate batteries to obtain the waste nickel cobalt lithium aluminate positive electrode powder; the lithium nickel cobalt aluminate positive electrode powder is ionized by high-energy electromagnetic waves, and the ionized lithium nickel cobalt aluminate 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 lithium nickel cobalt aluminate positive electrode powder are converted into harmless CO2 and H2O under the action of the atomic hydrogen H and the hydroxyl free radicals. 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 nickel-cobalt-aluminum 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 nickel-cobalt-aluminum 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 nickel cobalt aluminum 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 discharged lithium nickel cobalt aluminum oxide battery and remove the positive electrode sheet; place the positive electrode sheet in a vibrating screen to separate the lithium nickel cobalt aluminum oxide positive electrode material and aluminum foil, and the aluminum foil can be sold directly as a product; crush and grind the above lithium nickel cobalt aluminum oxide positive electrode material to obtain lithium nickel cobalt aluminum oxide positive electrode powder containing impurities (acetylene black, binder and organic solvent).

[0009] (3) The above-mentioned lithium nickel cobalt aluminum oxide cathode powder is placed in a fluidized bed reaction chamber, and air is used as the working gas to make the lithium nickel cobalt aluminum oxide cathode powder fluidized; electromagnetic treatment of the lithium nickel cobalt aluminum oxide cathode powder inside the fluidized bed reaction chamber is performed with electromagnetic waves of 3470-3550MHz until the cathode powder shows a weak electric spark; the LiNi in the lithium nickel cobalt aluminum oxide cathode powder 0.8 Co 0.15 Al 0.05 O2 undergoes physical ionization under the influence of high-energy electromagnetic waves to form LiNi. 0.8 Co 0.15 Al 0.05 O2 + and e - .

[0010] (4) According to LiNi 0.8 Co 0.15 Al 0.05 O2 / H2O = 69.4–70.5 (mass ratio), water vapor at 125–130℃ is injected into the fluidized bed reaction chamber; water molecules in LiNi 0.8 Co 0.15 Al 0.05 O2 + 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 lithium nickel cobalt aluminum 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 lithium nickel cobalt aluminum oxide cathode powder enters the air, resulting in clean lithium nickel cobalt aluminum 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 cathode materials for nickel-cobalt-aluminum batteries.

[0012] Among them, the conditions for physical ionization of lithium nickel cobalt aluminum oxide cathode powder are extremely stringent, requiring strict control of the electromagnetic wave frequency between 3470 and 3550 MHz.

[0013] Among them: the ionization equation of lithium nickel cobalt aluminum oxide cathode powder is LiNi 0.8 Co 0.15 Al 0.05 O2=LiNi 0.8 Co 0.15 Al 0.05 O2 + +e - .

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

[0015] Among them: LiNi 0.8 Co 0.15 Al 0.05 O2 + +H₂O=LiNi 0.8 Co 0.15 Al 0.05 O2+·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 lithium nickel cobalt aluminum 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 nickel cobalt aluminum 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 discharged lithium nickel cobalt aluminum oxide battery and remove the positive electrode sheet; place the positive electrode sheet in a vibrating screen to separate the lithium nickel cobalt aluminum oxide positive electrode material and aluminum foil, and the aluminum foil can be sold directly as a product; crush and grind the above lithium nickel cobalt aluminum oxide positive electrode material to obtain lithium nickel cobalt aluminum oxide positive electrode powder containing impurities (acetylene black, binder and organic solvent).

[0022] (3) The above-mentioned lithium nickel cobalt aluminum oxide cathode powder is placed in a fluidized bed reaction chamber, and air is used as the working gas to make the lithium nickel cobalt aluminum oxide cathode powder fluidized; the lithium nickel cobalt aluminum oxide cathode powder inside the fluidized bed reaction chamber is subjected to electromagnetic treatment with 3470MHz electromagnetic waves until the cathode powder shows a weak electric spark; the LiNi in the lithium nickel cobalt aluminum oxide cathode powder 0.8 Co 0.15 Al 0.05 O2 undergoes physical ionization under the influence of high-energy electromagnetic waves to form LiNi. 0.8 Co 0.15 Al 0.05 O2 + and e - .

[0023] (4) According to LiNi 0.8 Co 0.15 Al 0.05 O2 / H2O = 70.5 (mass ratio), 130℃ water vapor is injected into the fluidized bed reaction chamber; water molecules in LiNi 0.8 Co 0.15 Al 0.05 O2 + 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 lithium nickel cobalt aluminum 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 lithium nickel cobalt aluminum oxide cathode powder enters the air, resulting in clean lithium nickel cobalt aluminum 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 cathode materials for nickel-cobalt-aluminum batteries.

[0025] Example 2:

[0026] (1) The waste nickel cobalt aluminum 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 discharged lithium nickel cobalt aluminum oxide battery and remove the positive electrode sheet; place the positive electrode sheet in a vibrating screen to separate the lithium nickel cobalt aluminum oxide positive electrode material and aluminum foil, and the aluminum foil can be sold directly as a product; crush and grind the above lithium nickel cobalt aluminum oxide positive electrode material to obtain lithium nickel cobalt aluminum oxide positive electrode powder containing impurities (acetylene black, binder and organic solvent).

[0028] (3) The above-mentioned lithium nickel cobalt aluminum oxide cathode powder is placed in a fluidized bed reaction chamber, and air is used as the working gas to make the lithium nickel cobalt aluminum oxide cathode powder fluidized; the lithium nickel cobalt aluminum oxide cathode powder inside the fluidized bed reaction chamber is electromagnetically treated with 3550MHz electromagnetic waves until the cathode powder shows a weak electric spark; the LiNi in the lithium nickel cobalt aluminum oxide cathode powder 0.8 Co 0.15 Al 0.05 O2 undergoes physical ionization under the influence of high-energy electromagnetic waves to form LiNi. 0.8 Co 0.15 Al 0.05 O2 + and e - .

[0029] (4) According to LiNi 0.8 Co 0.15 Al 0.05 O2 / H2O = 69.4 (mass ratio), 125℃ water vapor is injected into the fluidized bed reaction chamber; water molecules in LiNi 0.8 Co 0.15 Al 0.05 O2 + 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 lithium nickel cobalt aluminum 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 lithium nickel cobalt aluminum oxide cathode powder enters the air, resulting in clean lithium nickel cobalt aluminum 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 cathode materials for nickel-cobalt-aluminum batteries.

Claims

1. This invention provides a method for deep cleaning of waste nickel-cobalt-aluminum battery cathode powder using high-energy electromagnetic waves, characterized in that: (1) The waste nickel cobalt aluminum 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 discharged lithium nickel cobalt aluminum oxide battery and remove the positive electrode sheet; place the positive electrode sheet in a vibrating screen to separate the lithium nickel cobalt aluminum oxide positive electrode material and aluminum foil, and the aluminum foil can be sold directly as a product; crush and grind the above lithium nickel cobalt aluminum oxide positive electrode material to obtain lithium nickel cobalt aluminum oxide positive electrode powder containing impurities (acetylene black, binder and organic solvent). (3) The above-mentioned lithium nickel cobalt aluminum oxide cathode powder is placed in a fluidized bed reaction chamber, and air is used as the working gas to make the lithium nickel cobalt aluminum oxide cathode powder fluidized; electromagnetic treatment of the lithium nickel cobalt aluminum oxide cathode powder inside the fluidized bed reaction chamber is performed with electromagnetic waves of 3470-3550MHz until the cathode powder shows a weak electric spark; the LiNi in the lithium nickel cobalt aluminum oxide cathode powder 0.8 Co 0.15 Al 0.05 O2 undergoes physical ionization under the influence of high-energy electromagnetic waves to form LiNi. 0.8 Co 0.15 Al 0.05 O2 + and e - . (4) According to LiNi 0.8 Co 0.15 Al 0.05 O2 / H2O = 69.4–70.5 (mass ratio), water vapor at 125–130℃ is injected into the fluidized bed reaction chamber; water molecules in LiNi 0.8 Co 0.15 Al 0.05 O2 + 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 lithium nickel cobalt aluminum 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 lithium nickel cobalt aluminum oxide cathode powder enters the air, resulting in clean lithium nickel cobalt aluminum 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 cathode materials for nickel-cobalt-aluminum batteries.

2. The method for deep cleaning of waste nickel-cobalt-aluminum battery cathode powder using high-energy electromagnetic waves according to claim 1, characterized in that: The conditions for physical ionization of lithium nickel cobalt aluminum oxide cathode powder are extremely stringent, requiring strict control of the electromagnetic wave frequency between 3470 and 3550 MHz.

3. The method for deep cleaning of waste nickel-cobalt-aluminum battery cathode powder using high-energy electromagnetic waves according to claim 1, characterized in that: LiNi 0.8 Co 0.15 Al 0.05 O2=LiNi 0.8 Co 0.15 Al 0.05 O2 + +e - The ionization equation is for lithium nickel cobalt aluminum oxide cathode powder.

4. The method for deep cleaning of waste nickel-cobalt-aluminum battery cathode powder using high-energy electromagnetic waves according to claim 1, characterized in that: The ionized lithium nickel cobalt aluminum 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 nickel-cobalt-aluminum battery cathode powder using high-energy electromagnetic waves according to claim 1, characterized in that: LiNi 0.8 Co 0.15 Al 0.05 O2 + +H₂O=LiNi 0.8 Co 0.15 Al 0.05 O2+·OH+H + 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 nickel-cobalt-aluminum 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.