Magnesium oxide is a white solid, often found as a powder. When fine particles of magnesium oxide are dispersed into the air, whether directly or when generated by the burning or cutting of magnesium metal, the resulting magnesium oxide fume is an inhalation hazard.
In aqueous media, it combines quickly with water to form magnesium hydroxide. Magnesium oxide is used as an antacid and mild laxative and has many nonmedicinal uses.
Method 1: Limestone is calcined at a high temperature under controlled conditions to produce calcined dolomite or dolime which upon reaction with magnesium chloride-rich brine produces magnesium hydroxide and calcium chloride. The insoluble magnesium hydroxide is then separated from the liquid calcium chloride carrier and calcined under controlled conditions.
Method 2: Light or heavy magnesium carbonate is exposed to red heat. After which, CO2 and H2O are expelled, and magnesium oxide is collected.
Medical Industry: Used as an antacid to relieve heartburn, sour stomach, or acid indigestion, as a laxative for short-term, rapid emptying of the bowel (before surgery, for example) and as a mineral supplement used to prevent and treat low amounts of magnesium in the blood.