Magnesite calcination

Because magnesite contains impurities such as SiO2, Al2O3, Fe2O3, and CaO in addition to MgO, it is possible to promote the decomposition of magnesite by calcination, and the growth of periclase crystals. In addition, under high temperature, impurities oxide Impurity oxides interact with MgO to form new minerals.

          The calcination of magnesite goes through four stages:

         (1) Cracks appear in magnesite grains at 500 ° C;

         (2) At 550 ° C, homogeneous magnesium oxide appears around the magnesite particles and penetrates into the interior of the magnesite grains;

         (3) Magnesite disappears at 650 ° C, and magnesium oxide is partially heterogeneous;

         (4) At 1100 ° C, tiny magnesite inclusions are formed around the periclase, and its color also turns brown. The temperature continued to rise until 1400 ° C, with little change, except that the periclase brown became darker.