Reburned magnesite

Magnesite can be divided into natural magnesite and seawater magnesite or synthetic magnesite. Natural magnesite mainly comes from natural magnesite, but it is difficult to obtain high-purity and high-quality products due to the restriction of raw ore quality. So far, seawater magnesite has become the main source of magnesite used in industrial developed countries. The theoretical content of MgO in magnesite is 47.3%, and other impurities include CaO, SiO2, iron, etc. The magnesite is heated to 700 ℃~800 ℃ in air to decompose, which is called "light burned magnesia", and further heated to more than 1530 ℃, it becomes inactive periclase to become hard burned magnesia, which is called "dead burned magnesia". Synthetic seawater magnesia for industrial production is made of seawater and digested dolomite. The precipitated Mg (OH) 2 is calcined to obtain MgO. The ratio of calcium to silicon in the synthetic magnesia used for unburned bricks is 0.3~0.5. The ratio of calcium to silicon in high-purity seawater magnesia is more than 1.7, and its high temperature strength is the highest.