The Organic Solvent Separation Processing Of Spent Lithium-ion Battery

Li-ion battery has been widely put into practice, meanwhile the amount of discarded Li-ion batteries gained a great increase. The lack of feasible and efficient disposal techniques is not only threatening the natural environment, but also wasting the nonrenewable metal resources of cobalt, aluminum and etc.The metal resources of cobalt and aluminum have high content in Li-ion battery and high economic value, and are the main objectives of Li-ion battery disposal and resources renewal. The practical methods of cobalt and aluminum renewal have been intensively investigated in this dissertation. Cobalt and aluminum are mainly contained in the anode material of Li-ion battery.In order to break through the limitation of current battery-disposal methods in separating aluminum from cobalt renewal, the organic solvent was innovatively used to dissolve the binding agent PVDF and dispart aluminum foil from anode active material. This not only avoids the influences from aluminum in cobalt extraction, but also renews aluminum in the form of simple substance. The organic solvents of DMAC and DMF were found to have the best performance in dissolving PVDF and disparting aluminum foil. The proper process conditions of solvent dosage, dissolving temperature and etc. are intensively investigated in the experiment of DMAC application. The multilevel dissolving technique has been found to be able to make the best use of solvents' dissolving capacity. The saturated solution can be directly recycled in distillation and turned into renewed solvent which has the same dissolving performance as the untapped one.After disparting from aluminum foil, the mixture of LiCoO₂ and acetylene black was lixiviated to extract cobalt ion. The leaching efficiency of cobalt was shown to be as high as 90% in the lixiviation experiments.The complexation method was used to deposit cobalt from the lixiviated solution, and complexation shows advantages in the phaseand oxidation-state control of cobalt hydroxide, β -Co(OH)2 was exclusively synthesized in the complexation deposition method.