Based on TG-DTA analysis

boron mud

the solid waste of boron chemical industry

was roasted in a muffle oven and a microwave furnace at different temperatures

and the roasted products were processed through alkaline leaching and acid leaching to extract separately valuable Si and Mg components. The effects of roasting methods and temperature on leaching rates of SiO2 and MgO were investigated. Chemical and phase compositions as well as micro-structures of the roasting products

obtained silica and magnesium oxide were analyzed and characterized by chemical analysis

XRD and SEM. The results indicate that the activity of the boron mud increases after both two types of roasting. The optimal process parameters are 600℃ and 30 min for the roasting in muffle oven and 500℃ and 10 min for doing in microwave furnace. At these conditions

the leaching rates of SiO2 and MgO reach 97.65% and 98.81% for former and 98.03% and 98.83% for later

respectively. The silica prepared

containing 92.20% SiO2

consists of nearly spherical grains with diameter ranges from 100 to 200 nm. And the magnesium oxide obtained

containing 93.05% MgO

makes of plate-like grains with diameter about 2 mm.