Millennial Lithium (ML.V) is still on track to publish a definitive feasibility study by this summer, and recent metallurgical test work conducted by SGS in Lakefield has now confirmed the lithium that will be recovered from the Pastos Grandes brines could be successfully upgraded to the standards required for battery grade lithium carbonate.
The minimum requirement for battery grade carbonate is to have a Li2O3 content of at least 99.5%, and the SGS test results indicated the brine could be upgraded to an average lithium carbonate grade of 99.92%, exceeding the minimum requirements to be used as a component for batteries. The purification test work was based on a representative sample of 600 liters with an average grade of 480 mg/liter and a Magnesium:Lithium ratio of approximately 5.2.
The process used by the lab was pretty standard. It used lime followed by a mechanical evaporation process and a selective precipitation method (using caustic soda and soda ash) to remove as much of the Calcium and Magnesium as possible. This resulted in an intermediate product of 10 liters with an average grade of 1.9% Lithium which was further concentrated until a final grade of 99.92% was reached. Additionally, the level of other elements that could have a negative impact on the performance of a battery was low or undetectable, which confirms Pastos Grandes could be an excellent option for battery manufacturers to secure their supply of lithium carbonate.