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CN-122006911-A - Method for separating graphite from magnetic impurities in lithium battery based on flotation-magnetic separation combination

CN122006911ACN 122006911 ACN122006911 ACN 122006911ACN-122006911-A

Abstract

The application provides a method for separating graphite from magnetic impurities in a lithium battery based on flotation-magnetic separation combination, which comprises the steps of S1, adding a collector and a foaming agent into black powder of the lithium battery for flotation, separating hydrophobic graphite to obtain a flotation product and a flotation residual material, and S2, carrying out strong magnetic separation on the flotation residual material to remove ferromagnetic impurities and realize separation of graphite and ferromagnetic impurities in the black powder of the lithium battery. The application obviously improves the separation efficiency of valuable components in the lithium battery black powder, and provides green and efficient process support for the lithium battery recycling industry.

Inventors

  • TANG CUNFU
  • LU BING
  • YAN CAINENG
  • XU WENBIAO
  • XIAO JIANBIN

Assignees

  • 秦田科技(湖州)有限公司

Dates

Publication Date
20260512
Application Date
20260107

Claims (10)

  1. 1. The separation method of graphite and magnetic impurities in the lithium battery based on the combination of flotation and magnetic separation is characterized by comprising the steps of S1, adding a collector and a foaming agent into black powder of the lithium battery for flotation, separating hydrophobic graphite to obtain a flotation product and a residual material after flotation, and S2, carrying out strong magnetic separation on the residual material after flotation to remove ferromagnetic impurities and realize separation of graphite and ferromagnetic impurities in the black powder of the lithium battery.
  2. 2. The method of claim 1, wherein step S1 comprises mixing the lithium battery black powder with water in a solid to liquid ratio of 1:3 to 1:5 to form an initial slurry.
  3. 3. The method of claim 2, wherein the initial slurry concentration is controlled between 20% and 25%.
  4. 4. The method according to claim 1, wherein the step S1 further comprises: Step S11, preparing and optimizing a collector to ensure the efficient separation of graphite in the flotation process; step S12, selecting and applying a foaming agent to ensure that a stable foam layer is formed in the flotation process; and step S13, the flotation process is controlled in detail, and effective separation of the hydrophobic graphite is realized.
  5. 5. The method of claim 4, wherein the step S11 further comprises: The method comprises a step S111 of preparing a collector from kerosene and methyl isobutyl carbinol, a step S112 of determining the proportion of the collector according to the kerosene and the methyl isobutyl carbinol to obtain a mixture of the collector, and a step S113 of adding the mixture into black powder of a lithium battery to be used together with a foaming agent for flotation.
  6. 6. The method of claim 5, wherein step S112 comprises a volume ratio of kerosene to methyl isobutyl carbinol of 2:1 to 4:1.
  7. 7. The method of claim 6, wherein the volume ratio of kerosene to methyl isobutyl carbinol is 3:1.
  8. 8. The method according to claim 1, wherein the step S2 comprises the step of controlling the water content of the material to be 15-25% by concentration and dehydration before the rest material after flotation enters the high-intensity magnetic separation.
  9. 9. The method of claim 8, wherein the step S2 further comprises: s21, configuring and operating the strong magnetic separator to effectively remove ferromagnetic impurities; and S22, directly treating the rest materials after flotation, and ensuring the process continuity.
  10. 10. The method of claim 9, wherein the step S21 includes a step S211 of using the wet-type strong magnetic separator as the strong magnetic separator, a step S212 of feeding the residual material after flotation into the wet-type strong magnetic separator, a step S213 of setting the magnetic field strength of the wet-type strong magnetic separator to 0.8-1.2 tesla, a step S214 of setting the drum rotation speed of the wet-type strong magnetic separator to 200-300 rpm, and a step S215 of setting the feeding speed to 0.5-1 ton/hr to control the feeding amount of the residual material after flotation.

Description

Method for separating graphite from magnetic impurities in lithium battery based on flotation-magnetic separation combination Technical Field The invention relates to the technical field of lithium battery recovery, in particular to a method for separating graphite from magnetic impurities in a lithium battery based on flotation-magnetic separation combination. Background The lithium battery recycling industry is in a rapid development stage, black powder is used as the most core metal-containing material after the waste lithium batteries are crushed, and the high-efficiency separation of the black powder directly determines whether the whole industrial chain can realize resource closed loop and green circulation, so that the importance is self-evident. The prior separation methods commonly used in the industry mostly adopt single flotation or single magnetic separation to treat the black powder, but the methods have obvious defects in actual production that when the flotation is used singly, graphite can float up partially but always carries a large amount of magnetic particles such as iron, nickel and the like to enter concentrate together, so that the grade of the final graphite is seriously lower, and when the magnetic separation is used singly, a large amount of fine graphite particles can be sucked into tailings together, so that the recovery rate of the graphite is greatly reduced. When the two processes are independently operated, graphite and magnetic impurities are just like being bound together forcedly, and high recovery and high purity can not be obtained in one process at the same time. The further technical difficulty is that graphite in the black powder has extremely strong natural hydrophobicity, magnetic impurities such as iron, nickel and the like are highly hydrophilic, the two diametrically opposite surface properties enable the graphite particles to be mutually adsorbed naturally in an aqueous medium, fine ferromagnetic particles are adsorbed on the surfaces of the graphite particles to form a graphite-magnetic impurity complex, the complex is neither completely floated nor pulled away by magnetic force, the complex is repeatedly rolled in a flotation tank but is not stripped all the time, and magnetic fields are repeatedly carried out due to the non-magnetism of graphite in a magnetic separator, so that the separation process falls into dead cycles of low graphite purity or large graphite loss. For example, in a practical production line, when an operator tries to increase the dosage of a flotation collector to forcibly pull up graphite, the entrainment of iron and nickel impurities is doubled immediately, the grade of graphite is reduced from 70% to below 50%, conversely, when the intensity of magnetic separation is increased to try to suck the impurities clean, a large amount of fine graphite particles are lost along with tailings, and the recovery rate is reduced from 85% to below 60%, so that the repeated pull saw has low efficiency and high cost of the whole production line. Therefore, how to use the natural hydrophobicity of graphite to float the graphite efficiently in the same process flow, and thoroughly peel off and accurately remove ferromagnetic impurities closely adsorbed on the surface of the graphite at the same time becomes a key problem of recycling black powder of lithium batteries. Disclosure of Invention The invention provides a method for separating graphite from magnetic impurities in a lithium battery based on flotation-magnetic separation combination, which aims to solve the technical problems in the background art and comprises the steps of S1, adding a collector and a foaming agent into black powder of the lithium battery for flotation, separating hydrophobic graphite to obtain a flotation product and a flotation residual material, and S2, carrying out strong magnetic separation on the flotation residual material to remove ferromagnetic impurities and realize separation of graphite from ferromagnetic impurities in the black powder of the lithium battery. Further, the step S1 comprises the step of mixing lithium battery black powder and water according to a solid-to-liquid ratio of 1:3 to 1:5 to form initial slurry. Further, the concentration of the initial slurry is controlled between 20% and 25%. Further, the step S1 further includes: Step S11, preparing and optimizing a collector to ensure the efficient separation of graphite in the flotation process; step S12, selecting and applying a foaming agent to ensure that a stable foam layer is formed in the flotation process; and step S13, the flotation process is controlled in detail, and effective separation of the hydrophobic graphite is realized. Further, the step S11 further includes: The method comprises a step S111 of preparing a collector from kerosene and methyl isobutyl carbinol, a step S112 of determining the proportion of the collector according to the kerosene and the methyl isobutyl carbinol to obtai