The Bureau of Mines studied the extraction of lithium from lithium- containing clays by chlorination with hydrogen chloride (hcl). In bench-scale laboratory investigations, hcl-h2o mixtures were used to selectively chlorinate lithium, but not calcium or magnesium, in lithium-containing clays. The addition of calcium carbonate to the clay was found to improve the lithium recovery. Reaction conditions found to affect the lithium recovery were ratio of clay to carbonate, reaction temperature, and hcl concentration. The best conditions for selective chlorination of the lithium were 2:1 clay- carbonate, 750 deg. C, and 20 wt-pct hcl. The experimental results and trends in lithium extraction are explained using thermodynamic relationships.