METHOD OF PREPARING MAGNESIUM OXIDE Russian patent published in 1999 - IPC

FIELD: chemical industry, more particularly production of magnesium oxide from natural stock, more specifically serpentinite. SUBSTANCE: method comprises dissolving magnesium oxide in mineral acid, separating insoluble residue from solution, purifying solution from extrinsic metals, precipitating magnesium-containing compound and subsequently heat treating it. Mineral acid is sulfuric acid having at least 20 wt % concentration, separation of insoluble precipitate from solution is carried out by cooling mixture formed at stage where stock is dissolved in acid to attain crystallization state and subsequently washing it with water. Purification of solution from extrinsic metals is carried out by precipitating the latter as hydroxides at pH of 5-7 and separating the resulting precipitate from solution. Magnesium-containing compound is precipitated as magnesium hydroxide at pH of 10-12, and heat treatment is carried and in two stages at 200- 450 C and at 450-850 C, and the resulting product is then washed with water. EFFECT: more efficient economical and ecologically pure method for preparing highly pure magnesium oxide.