1. Hebei Messi Biology Co., Ltd. stated that active magnesium oxide is magnesium oxide with hydration ability, which can be expressed in terms of hydration rate, iodine absorption value, citric acid value, specific surface area, etc.
2. Formation of active magnesium oxide. During the calcination of magnesite ore in the kiln, the calcination temperature of the ore is different due to technical reasons. When the temperature reaches 400-600℃, its internal structure is loose, the intercrystalline pores are the highest, and magnesium oxide shows the highest activity.
3. When the calcination temperature reaches 750-850℃, the intercrystalline porosity decreases, reaching the optimal range of magnesium cement reaction, and the activity is moderate. When the calcination temperature is greater than 900-1000℃, over-fired magnesium oxide is formed, and its activity is very low or even inactive. Within a certain range of activity, the product quality of high-activity ones is good, and the product quality of low-activity ones is poor, but this is not the case with under-fired magnesium oxide. The higher its activity, the more intense the reaction, the more concentrated the heat release of magnesium chloride, and the worse the product quality, easy to crack and low strength.