Extraction of lithium and aluminium from bauxite mine tailings by mixed acid treatment without roasting.

Bauxite mine tailings can be used as the reserve resources of aluminium and lithium. In this study, a less energy consumption treatment method for extracting aluminium and lithium from bauxite mine tailings has been proposed, which used mixed acid to leach aluminium and lithium from tailings directly, avoided roasting for reducing energy consumption, and obtained effective results.The minerals in the tailings are kaolinite, diaspore, boehmite, anatase and illite, among others. The minerals have fine dissemination sizes and low liberation. Under the leaching conditions of Al and Li of an acid concentration of 60%, a liquid-solid ratio of 4 mL/g, a reaction temperature of 100 °C and a reaction time of 3 h, the highest leaching rates of Al and Li are 88.64% and 96.35%, respectively. In the leaching process, phosphoric acid reacts with Al and Li in the strong acidic environment provided by sulphuric acid to produce heteropoly acids or heteropoly acid salts that dissolve in the solution.