摘要
Salt roasting with Na2SO4 + CaCl2 followed by water leaching was used to extract alkali metals from lepidolite. The experiments indicated that the best mass ratio of lepidolite /Na2SO4/CaCl2 during roasting was 1:0.5:0.3. The extraction of Li, Rb and Cs were all > 90%after 0.5 h at 880 掳C. The recovery of Li was essentially constant when roasted at 830-930 掳C. The flexible roasting condition is easily controlled in industrial application. After leaching in water, the solution was cooled to 鈭?#xA0;5 掳C for 2 h to crystallise 92.1%of the sulphate and 3.9%of the chloride as Na2SO4路10H2O and NaCl, respectively. Evaporation and precipitation using Na2CO3 produced Li2CO3 crystals with > 99.5%purity and a solution from which Rb and Cs could be recovered.