Recovery of valuable metals from lepidolite by hydrochloric acid leaching and kinetics on dissolution of lithium

The leaching process and kinetic behavior of lepidolite in hydrochloric acid were explored systematically. The influence of leaching conditions on the leaching efficiency of valuable metals in lepidolite was investigated. Under optimized conditions, the leaching efficiencies of Li, K, Rb, Cs and Al are 92.02%, 93.31%, 88.59%, 86.75% and 81.07%, respectively. Kinetics research results show that the leaching process conforms to the shrinking core model that is under the mixed control of chemical reaction and diffusion through the solid product layer. In addition, the contribution of solid product layer diffusion to the leaching gradually expands as the temperature rises, but it is still significantly less than the contribution of chemical reaction. Cost saving in the neutralizing agent and leaching processes makes hydrochloric acid an economical leaching agent for lepidolite. Finally, the Li 2 CO 3 product with a purity of 99.89% was synthesized from the hydrochloric acid leachate.