Study on the preparation of active magnesium oxide and magnesium clathrate cement from water magnesite

Due to the limitation of technical and economic conditions, the large amount of magnesium resources in the western salt lake of China has not been effectively utilized so far, and the research and development of magnesium salt products (such as magnesium chloride cement, etc.) is an important development direction for the high utilization of magnesium resources in the western salt lake, which has important economic and social significance.

Reactivat magnesium oxide is an important inorganic chemical product. The preparation of active magnesium oxide by direct calcination of hydromagnesite is a short process and low cost. In this paper, the active magnesium oxide was prepared by direct calcination of hydromagnesite, the activity of magnesium oxide was determined by citric acid method, the effect of calcination temperature and time on the activity of magnesium oxide was studied, the calcination process conditions were optimized, and the effect of the activity of magnesium oxide on the strength of magnesium chloroxide cement was also studied. The microstructure of magnesium oxide was studied by X-ray diffraction and scanning electron microscopy to explore the microscopic mechanism of the change of product magnesium oxide activity.

The results showed that with the increase of calcination temperature, the average grain size of magnesium oxide increased, the lattice constant decreased, the amount of lattice distortion decreased, the activity decreased; calcination temperature of 550 ℃, calcination 1h obtained the highest

activity of magnesium oxide, CAA value of 50.5s; small grain size, low crystallinity, small average particle size, rough surface of magnesium oxide activity is higher. The thermal decomposition tail gas of magnesium chloride contains a large amount of hydrogen chloride gas, direct emission is not only harmful to human health, but also will cause the waste of resources, so it is necessary to absorb the hydrogen chloride tail gas.

In this paper, water was used as the absorbent to treat the hydrogen chloride exhaust gas, and the single-stage absorption experiment was designed and completed to investigate the effects of the temperature of the absorbent, the temperature of the inlet gas, the amount of liquid spraying, and the mass concentration of the circulating spraying liquid on the absorption efficiency.