Novel liquid–liquid extraction and ion exchange processes for hydrometallurgical recovery of lithium, nickel and cobalt from lithium-ion battery waste leachate

Abstract

Hydrometallurgy is a promising technology for recovering valuable key components such as Li, Ni and Co from spent lithium-ion batteries. In this thesis, flowsheets of alternative processing routes were developed to yield high-purity products with high recovery yields. Two hydrometallurgical separation processes were studied: i) the direct extraction of Li from lithium-ion battery waste leachate (LIBWL) and ii) the recovery and purification of a Li+Ni+Co mixture using continuous ion exchange.

Batch equilibrium experiments and McCabe–Thiele analyses were carried out to develop a new solvent extraction process to directly recover Li from LIBWL. The employed extraction system, TBP/FeCl3 in kerosene with AlCl3 as a supplementary chloride source, selectively extracted 87.7% of Li in a single extraction stage. The novel processing route yielded 99.1% pure Li-stripping liquor with a Li concentration of 13.95 g L-1. The direct extraction of Li guarantees high recovery yields and is a viable alternative for the recovery of Li from LIBWL.

The chelating resin Lewatit® MDS TP 260 with aminomethylphosphonic functional group selectively removed the impurities Al, Cu, Fe and Mn from LIBWL. Single-column experiments were carried out to design a continuous multicolumn ion exchange process. The continuously operated laboratory-scale SMB-type configuration processed 1.64 L (L h)-1 of leachate to yield 34.04 g (L h)-1 of pure Li+Ni+Co raffinate. Very high recovery yields of 100%, 99.2% and 96.9% for Li, Ni and Co were achieved and demonstrated superior performance over conventional state-of-the-art single-column ion exchange, solvent extraction and precipitation processes.

Overall, the developed flowsheets allow for the processing of high-purity products and guarantee high recovery yields in lithium-ion battery (LIB) recycling. Future research could further explore novel alternative processing routes through clever choice of the chemical extraction system and the separation process configuration to overcome the conventional selectivity order and maintain high recovery yields in difficult hydrometallurgical separations.