The carbonization method of lithium carbonate is characterized by its high reaction efficiency and simple process.It has become the mainstream process for battery-grade lithium carbonate production.However,in the process of preparing battery-grade lithium carbonate by carbonization method and with salt lake lithium concentrate as raw material,there are still problems such as low carbon dioxide utilization in the carbonization process,poor removal of impurities in the carbonized liquid and low lithium yield.With salt lake lithium concentrate as raw material,process optimization experiments were carried out from three main links：carbonization,purification and pyrolysis,that is,changing from atmospheric carbonization to pressurized carbonization,and using a combination of chemical purification and ion exchange resin adsorption to remove carbonization.Impurities in the liquid were changed from conventional pyrolysis to pressure pyrolysis,which can increase the carbon dioxide utilization rate in the carbonization processed to 87.4%,the removal rate of calcium and magnesium in the purification processed to 97.92% and 96.09%,and the direct yield of lithium in the whole processed to 82.27%.