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

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.