A NEW TECHNIQUE OF MAGNESIUM ELECTROLYSIS WITH BISCHOFITE FROM QINGHAI SALT LAKES IN CHINA

摘要

The Qinghai salt lakes in China have plenty of magnesium and potassium resources. Every year, Potassium fertilizer is produced with the by-product of bischofite. At present, the bischofite cannot be used and is discarded. This causes not only the waste of resources, but also the formation of magnesium compounds that are harmful to the environment. Therefore, a comprehensive utilization of bischofite is being studiede. This paper presents a combined process using bischofite: preparation of magnesia with ammonia and direct electrolysis of magnesia with the LaCl_3-MgCl_2 system as support electrolyte. This process produces magnesium of 99.5% purity; the current efficiency is 90%; the energy consumption is 11.5kWh/kg Mg; and carbon dioxide is discharged on a carbon anode. This new technique has low energy consumption, high current efficiency and less pollution for the environment.