Method for producing high-purity magnesium hydroxide, high-purity magnesium oxide and high-purity magnesia series magnesium products by using salt lake brine

The invention discloses a method for producing high-purity magnesium hydroxide, high-purity magnesium oxide and high-purity magnesia series magnesium products by using salt lake brine. Purified salt lake brine is used as a raw material, high-purity magnesium hydroxide and high-purity basic magnesium carbonate are respectively prepared by two-stage magnesium precipitation reaction of ammonia and ammonium bicarbonate, and the total conversion efficiency of magnesium reaches 97-98%. The high-purity magnesium hydroxide is further processed to produce high-purity ultrafine magnesium hydroxide, high-purity heavy magnesium oxide, high-purity ultrafine magnesium oxide, high-purity sintered magnesia, high-purity fused magnesia and other products; and the high-purity light magnesium oxide product isproduced by further processing the high-purity basic magnesium carbonate. Ammonia vapor is obtained from an ammonium chloride mother liquor, obtained after basic magnesium carbonate is separated through two-stage magnesium p