Recovery of Li from lithium aluminum silicate (LAS) glass-ceramics after heat treatment at 1000 °C and Ca salt-assisted water leaching in two stages before and after calcination at 600 °C

Abstract

In this study, the leaching of Li from lithium aluminum silicate (LAS) glass-ceramics was conducted using a Ca salt additive and water, with the content of other impurities at a minimum. LAS glass-ceramics were heat-treated at 1000 °C to increase the reactivity with leachate before the water leaching process. Various types of Ca salts were employed, and their effects on Li leaching were investigated. The reaction temperature, reaction time, and mass ratio of the Ca salt to the LAS glass-ceramics were considered as leaching parameters. Approximately 42.1% of Li was found to be leached by water at 100 °C via an ion exchange reaction between Li+ and Ca2+. X-ray diffraction revealed a peak shift of the leach residue, indicating that Li+ was substituted by Ca2+. When water leaching was conducted again after calcining the leach residue at 600 °C, Li leached from the LAS glass-ceramics exceeded 99.9%. Thus, Li can be recovered from LAS glass-ceramics using only a Ca salt and distilled water, without the requirement of other chemicals.