The main crystal phase of brucite melting point is 2800℃, in the vacuum 1600℃ began to sublimate, in the reduction atmosphere above 2000℃ began to sublimate, density is greater than 3.40g/cm, porosity 0% ~ 10%, Mohs hardness 5.5, alkali slag erosion resistance is very strong. Cubic magnesite is usually cube, octahedron or irregular granular, cube cleavage is complete; Linear expansion coefficient α=(14 ~ 15)×10/℃(0 ~ 1500℃), and increases with the increase of temperature.
The thermal conductivity λ=123.5W/(m·K) (at 100℃) decreases with the increase of temperature. The elastic modulus is 1.96MPa. The chemical properties are stable, and there is no reaction or weak reaction between various refractories except silicon bricks at a high temperature of 1500 ° C. The grain size of magnesite increases with the increase of calcination temperature and holding time, and the corresponding slag resistance is also improved. China's quality requirements for fused magnesia are shown in the table.
Production technology
The production process of fused magnesia is short and simple, but the equipment investment and resource consumption are large. China's fused magnesia industry mostly uses electric arc furnace molten natural magnesia ore to prepare fused magnesia. The production technology and equipment are backward, the power is low, the capacity is small, the efficiency is low, the degree of automation is low, the produced fused magnesia product grade is not high, resulting in low utilization rate of magnesium resources and serious environmental pollution.
