METHOD FOR PREPARING HIGH-PURITY LIGHT-BURNED MAGNESIA FROM LOW-GRADE MAGNESITE BY CALCINATION TO REMOVE CALCIUM AND SILICON

Disclosed is a method for preparing high-purity light-burned magnesia from low-grade magnesite by calcination to remove calcium and silicon. The method comprises: rinsing and crushing low-grade magnesite comprising dolomite and quartz, calcining magnesite powder having a particle size of 2.5 to 20 mm at 600°C to 700°C for 1 to 2.5 h to obtain a mixture of the separated magnsite, dolomite and quartz, then subjecting the mixture to selective grinding, and screening and grading the resulting product to obtain ground product having a particle size of -0.074 mm; subjecting magnesite powder having a particle size of 0.1 to 2.5 mm to blow calcination in a suspension furnace at 570°C to 670°C for 0.5 to 2 h to obtain light-burned magnesia recovered by suspension calcination; and subjecting the ground product and the suspension calcined light-burned magnesia to purification by winnowing, and thus obtaining the high-purity light-burned magnesia. The method can effectively address the difficulty in separating dolomite a