Abstract:

The technical route of preparing lithium carbonate by ammonium sulfate process was studied for the medium and low grade lithium clay with w（Li₂O）<2.0% in Yifeng.The precious metals such as rubidium and cesium from the lithium extraction mother liquor were further studied.The mother liquor after carbonization and extraction of lithium contains several dissolved sulfates of metals such as rubidium and cesium.Using stepwise crystallization method,the less soluble alum salts such as rubidium and cesium,were precipitated in the previous step of higher temperature,while alum salts such as potassium and ammonium were precipitated in the later step of lower temperature.By this way,the rubidium and cesium alum and ammonium and potassium alum were separated.The alum salts such as aluminum potassium sulfate and aluminum ammonium sulfate were roasted at high temperature to decompose as potassium sulfate and alumina.

Key words: medium and low grade lithium clay, ammonium sulfate process, lithium extraction tail liquid, alums of rubidium and cesirm comprehensive utilization