Leaching Behavior of Lithium-Rich Beneficiation Tailings in Caustic Solution

This paper systematically investigated the leaching behavior of bauxite lithium-rich beneficiation tailings in caustic solution, together with their phase and morphological changes. The main chemical compositions (mass percent) of bauxite flotation tailings were 40.56% Al 2 O 3 , 34.00% SiO 2 , 4.34% K 2 O, 3.31% TiO 2 , 1.83% Fe 2 O 3 , 0.37% MgO, and 0.59% Li 2 O. The occurrence state of the lithium-bearing mineral is cookeite. Elevated temperature, high alkali concentration and prolonging time can improve the leaching ratio of lithium, while excessive reaction time weakens the lithium leaching. The optimum leaching conditions are a temperature of 200°C, a time of 30 min, an alkali concentration of 250 g/L and a liquid-to-solid ratio of 10:1. Under these experimental conditions, the leaching ratios of lithium, alumina, silicon, and potassium were 96.22%, 10.84%, 16.18%, and 47.8%, respectively. This work may provide a new way of utilizing lithium-rich bauxite flotation tailings.