A novel process for extracting lithium from lepidolite

A novel technique was developed to extract lithium from lepidolite.The lepidolite was pre-roasted at a high temperature with water steam atmosphere for defluorination. Then the defluorinated lepidolite was leached in a lime–milk autoclave. Various parameters including the defluorination percentage of lepidolite, milling time, temperature, time, lime-to-defluorinated lepidolite ratio, and liquid-to-solid ratio in the leaching process were optimized. The lithium extraction efficiency can reach 98.9% under the optimal conditions. The purity of the lithium carbonate obtained can be up to 99.9%.

► A lime–milk autoclave process was used to extract lithium from lepidolite.
► The leaching efficiency of lithium reached 98.9% under the optimal condition.
► The purity of the lithium carbonate obtained can be up to 99.9%.