Magnesite is an important industrial mineral composed of magnesium carbonate (MgCO3). Pure magnesite is theoretically 47.8% MgO and 52.2% CO2. It is the source of two-thirds of the 9 Mt of magnesia (MgO) used annually throughout the world; 25% is extracted from sea water, with the balance coming from brines or other mineral sources such as serpentinite or brucite.
Its main use is in heat resistant linings. Electrofused magnesia is a strong, abrasion-resistant material used in premium grade refractories and ceramics. Magnesium metal can be produced from magnesite by electrolysis of magnesium chloride. World production of magnesium metal in 1998 was 369 000 t. Predictions for strong growth in demand for this strong, lightweight metal in the automotive industry has resulted in feasibility studies being undertaken in many places throughout the world, including South Australia.
TYPICAL MAGNESITE ORE