Efficient separation and extraction of lithium from low-grade claystone by chloride salt-enhanced roasting process

The exploitation and extraction of lithium resources are mainly hard rock ore and salt lake brine. However, with the increasing demand of lithium resource market, the developed resources cannot meet the demand gap of lithium resource. In China, as a natural lithium source with considerable reserves, the exploitation and extraction of clay lithium resources can effectively relieve the pressure of lithium resource import. In this study, a green extraction process of low-grade lithium claystone treated by chlorination roasting-water leaching was proposed. The mechanism of lithium conversion under chlorination conditions was also investigated to reveal the fugitive form of lithium in claystone and its migration behavior during the extraction process. The experimental results showed that the optimal reaction conditions were 800 degrees C, the mixing ratio of the claystone and CaCl2 was 1:0.5, the roasting time was 2 h, the leaching temperature was 90 degrees C, and the leaching time was 3 h. Under such treatment conditions, the recovery efficiency of lithium could reach 92.35 %. Compared with the traditional roasting-acid leaching method of lithium claystone, it is more environmentally friendly and economical, and has good application prospects.