THE CHEMISTRY OF BORATE IN SALT LAKE BRINE II. HYDRATED Mg-BORATE CRYSTALLIZING OUT FROM CONCENTRATED MAGNESIUM CHLORIDE BRINE

The concentrated boron-containing brine was cooled in steps with stirring to 0℃, -10℃ and -20℃, with intervals of 8 hours to one week between each. The salts crystallized out at each temperature were removed accordingly. The final clear solution was then kept for a long time at room temperature and -20℃ respectively.Hydrated Mg-borates crystallized out from these solutions. They have been analysed by chemical analysis,thermal analysis, X-ray and infrared analysis, and these analytical results show that the hydrated Mg-borates crystallized out from the said brine at room temperature and at -20℃ are identical, being MgO·3B_2O_3·7(1/2)H_2O.