Magnesium oxide is commonly known as bitter earth, also called magnesium oxide. Magnesium oxide is an alkaline oxide, which has the generality of alkaline oxide, belongs to a gelling material. White powder (light yellow is magnesium nitride), odorless, tasteless, non-toxic, is a typical alkaline earth metal oxide, chemical formula MgO. White powder with a melting point of 2852 ° C, a boiling point of 3600 ° C, a relative density of 3.58 (25 ° C). Soluble in acid ammonium salt solution, insoluble in alcohol. Solubility in water is 0.00062 g / 100 mL (0 ° C) 0.0086 g / 100 mL (30 ° C). When exposed to the air, it easily absorbs moisture carbon dioxide gradually becomes basic magnesium carbonate. Lighter products are faster than heavier products. When combined with water, magnesium hydroxide is formed under certain conditions. The reaction is slightly alkaline. Is 10.3. It is soluble in acid ammonium salt, hardly soluble in water, its solution is alkaline. Insoluble in ethanol. Strong refraction in the visible near-ultraviolet range. Magnesite (MgCO3), dolomite (MgCO3 · CaCO3) seawater are the main raw materials for the production of magnesium oxide. Thermal decomposition of magnesite dolomite yields magnesia. Treatment of seawater with slaked lime yields magnesium hydroxide precipitation, burning magnesium hydroxide yields magnesium oxide. It can also use the magnesium chloride halide obtained the comprehensive utilization of seawater the bromine-extracted brine as a raw material, add sodium hydroxide sodium carbonate to generate magnesium hydroxide basic magnesium carbonate precipitation, then burn to obtain magnesium oxide. China mainly uses magnesite, dolomite, brine brine as raw materials.

Mainly used in the production of magnesite products. Light-burned magnesia is mixed with magnesium chloride aqueous solution at a certain ratio, which can be gelled hardened into a hardened body with certain physical mechanical properties, which is called magnesite cement. Magnesite cement, as a new type of cement, has the advantages of light weight high strength, fire insulation, energy saving environmental protection, etc., can be widely used in building materials, municipal administration, agriculture, machinery other fields.