Literature Review and Thermodynamic Modelling of Roasting Processes for Lithium Extraction from Spodumene

Abstract

This review adds to the public domain literature on the extraction of lithium from mineral ores. The focus is on the pyrometallurgical pre-treatment of spodumene. Information on the phase transformation from α to β, the heat treatment methods as well as the behavior of various compounds in the roasting processes are evaluated. Insight into the chemical thermodynamics of the baking process is evaluated using HSC Chemistry software up to 1200 °C. It was observed that the alkaline, sulfation, chlorination (using Cl2 and CaCl2), carbonizing (to form Li2CO3) and fluorination processes were feasible either throughout or at a point within the temperature range considered. Chlorination using KCl and carbonizing to form Li2O are the processes found to be nonspontaneous throughout the temperatures considered.