Separation of the Electrolyte—Solvent Extraction

The extraction of electrolyte from lithium-ion batteries is a possibility to remove the high boiling organic components and the conducting salt from the battery material in the recycling of lithium-ion batteries. In these studies, dimethyl carbonate was employed as organic solvent. The influence of temperature and solvent to solid mass ratio have been tested with Panasonic CGR 18650 batteries in a stirred vessel. Although the conducting salt was successfully extracted with a crossflow extraction with four stages, the remaining fluoride loading of the battery material was too high for further processing. Therefore, a second series of extractions with water was used to remove fluoride. The combination of four extraction stages with dimethyl carbonate and six stages with water for the processing of hybrid electric vehicle batteries resulted in a fluoride loading of 173.3 mg per kg fine fraction of the raffinate. Suggestions for the design of an extraction apparatus based on the experiments were worked out.