Lithium extraction from a Li-rich kaolin resource through Na2SO4 roasting and water leaching

Abstract

In this study, lithium extraction from a Li-rich kaolin is performed by roasting with Na₂SO₄ and water leaching. The thermal analysis of the Li-rich kaolin is characterized by TGA and DSC analysis. The comparison tests are conducted through roasting alone and H₂SO₄ leaching, in the aspects of ions concentration, Li recovery and solid wastes. Under Na₂SO₄ roasting and water leaching, 84 % of Li is leached out, which is a little lower than the H₂SO₄ method. Meanwhile, the leached Al and Fe are very low, which is highly beneficial to the purification process. After precipitation, a Li₂CO₃ product of 95 % in purity is obtained. However, for the H₂SO₄ method, Li₂CO₃ is hardly obtained because the Li is mainly lost in the purification process. And the process pH is much lower, leading to a high amount of solid wastes. This study might give a clue for the lithium recovery from Li-rich kaolin resources.