Environmentally Friendly Separating of Fine Copper Particles from Lithium Iron Phosphate and Graphite by Centrifugal Gravity Concentration

Abstract

The existing pretreatment method for recycling spent lithium iron phosphate (LFP) batteries effectively separates most of the copper foil. However, a small amount of fine copper particles (CP) remains in the LFP battery waste, which is mainly composed of graphite and LFP, affecting the subsequent smelting. Centrifugal gravity concentration (CGC) is a physical separation method that is highly efficient and environmentally friendly and is often used for the separation of fine-grain materials. In this study, it was used for the deep removal of CP from LFP battery waste. The dynamics analysis of the particles in the CGC indicated that CP can be effectively separated from graphite and LFP. The effects of fluidizing water pressure (FWP), relative centrifugal force (RCF), pulp density, and feeding rate on Cu grade, Cu recovery, and Cu separation efficiency (SE) were investigated by single-parameter experiments and response surface methodology (RSM) in CGC. The findings indicate a substantial impact of FWP and RCF on copper recovery, contrasting with the limited influence observed for pulp density and feeding rate on the recovery of Cu. The predicted outcomes from the RSM for Cu grade, Cu recovery, and Cu selectivity (Cu SE) were 85.1993%, 70.0271%, and 67.4004, respectively, under the conditions of FWP at 39.2697 kPa and RCF at 91.9 G. By means of both theoretical analysis and experimental validation, a novel and environmentally sustainable process for the recovery of CP from waste LFP batteries has been proposed.

Graphical Abstract

A technological process for the deep removal of fine copper particles from lithium iron phosphate battery waste using centrifugal gravity concentration.