Magnesium oxide formula: MgO Molecular Weight: 40.304 Physical properties: white amorphous powder magnesium oxide, tasteless, odorless, non-toxic. The relative density of 3.85 (25C). Melting point 2852C, the boiling point of 3600C. Magnesia also contains three (saying) substances: under-firing products, over-burning product, active magnesium oxide, are reflected by the light burning kiln, (coal and ore sintering way apart, so fewer impurities) can always control kiln temperature (by controlling the kiln temperature to increase the content of active magnesium oxide)