Extraction of lithium from cookeite-bearing claystone by chlorination roasting: From thermodynamic calculation to experimental practice

With the rapid increase in lithium consumption, extracting lithium from unusual lithium resources has attracted much attention. Herein, a lithium-bearing claystone sample was characterized to determine the existence state of lithium, and the thermodynamic and practical feasibility for extracting lithium from the claystone was evaluated. The analysis indicates that cookeite is the main independent lithium-containing phase in the claystone, which has an estimated Gibbs free energy of formation: −8283.7 + 1.586 T (kJ·mol −1 ). Further thermodynamic calculation demonstrates that the chlorination roasting process using CaCl 2 as the chlorinating agent is suitable for lithium extraction from the claystone. The experiment results of chlorination roasting followed by water leaching show that under optimized conditions, the extraction efficiency of lithium can reach 84.17 %, and the obtained leaching liquor is suitable for lithium carbonate preparation. It is believed that these results will provide an avenue toward development of highly efficient processes for utilization of the unusual lithium resource.