Process for extracting and recovering lithium values from lithium bearing materials

Abstract

A process for recovering lithium from lithium-bearing materials, in particular lithium bearing silicates such as spodumene, is provided. The process involves the steps of mixing the lithium-bearing material with a source of fluoride, such as calcium fluoride or hydrogen fluoride, in the presence of sulphuric acid at 90° C. for ≥3 h to extract ≥80% Li. Lithium values may be recovered as >98% purity lithium carbonate by raising the pH of the pregnant liquor solution (PLS) to pH<4 to precipitate Al and fluoride from solution, with a subsequent softening step to bulk remove excess calcium sulphate, followed by evaporation and precipitation of lithium carbonate.

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