PREPARATION OF MAGNESIUM SILICATE FROM DOLOMITE BY PRECIPITATION METHOD

Abstract

Preparing magnesium oxide from dolomite was widely studied in the last decide, while preparing magnesium silicate from the same rock is still not fully understood. Therefore, this studyis aimed to obtain high purity magnesium silicate from dolomite by using two steps. Thefirst stepwas preparing of magnesium chloride solution from dolomite by using hydrochloric acid.While, the secondstep of this workwas involved the preparation of magnesium silicate by using precipitation reaction method from magnesium chloride solution and sodium metasilicate solution. A number of different parameters weremonitored in this study to obtain the best conditions for preparing magnesium silicate. Theseparameters were included; reaction temperature (30, 50, and 70 C°), feeding rate (0.5, 1, 3, and 5 ml/min) of sodium silicate, concentration (1.5, 2.5, 5, 15, 25and 35vol. %) of sodium silicate, and calcination temperature (750, 900, 1000, and 1100 C°) The chemical analysis and mineralogical composition were reflected that the production of magnesium silicate in this study was achievedwith purity 97.5%. This production was demonstrated the optimum condition which is at 70 C° of reaction temperature, 1 ml/min feeding rate of Na2SiO3, 1.5% concentration ofNa2SiO3, and 1000-1100 C° for 2 hours for calcination temperature. In addition, the best molar ratio of MgCl2.6H2O:Na2SiO3 was1:0.5.