Study on the dependence between extraction of valuable components and sintering temperature of lithium mica ores

The studies on a material composition of ore have showed that the only industrially valuable mineral of lithium is lithium-containing mica, whose composition is between polylithionite and aluminum-celadonite, known as Mg-polylithionite. Its characteristic feature is finely dispersed precipitates and close interpenetration with minerals of the aluminosilicate matrix of rocks. Further studies have showed that mica ore of the deposit cannot be beneficiated by physical methods due to low contrast range of physical properties of lithium-containing minerals with rock minerals. In view of the above, the authors studied a possibility of extracting valuable components by hydrometallurgical methods after preliminary roasting. To carry out sintering, the prepared burden contained ore, phosphogypsum of the Almalyk Chemical Plant and potassium sulfate in a ratio of 1:0.3:0.2. The burden was annealed in a muffle furnace within a temperature range of 900–1050 oC and an interval of 50 oC within 2 h. The sintered cake, after cooling down to room temperature, was ground to a size of less than 500 μm and leached with distilled water in an agitation mode at a rotation speed of an overhead blade stirrer of 180 min–1 at a solidliquid ratio of 1:1. The performed tests on sintering ore with calcium and potassium sulfates have showed that the extraction rate of lithium into a solution was 89 % at 950 oC, the extraction rate of rubidium at such temperature was 32.22%. Maximum extraction rate of rubidium of 57.18% was achieved at 900 oC, the extraction rate of lithium at such temperature was 79.35%. A further application of the lithium sorption extraction from process solutions will contribute to obtaining lithium carbonate of a battery grade.