Preparation of Magnesia from Hydromagnesite Ore by Calcination

Hydromagnesite was calcined into light-burned magnesia, and the effects of calcination conditions, such as the size fraction of the ore and calcination temperature, and holding time on the loss on ignition and MgO grade were investigated. The calcination mechanism of hydromagnesite ore was analyzed by characterizing the calcinate with respect to its chemical and physical properties. The results indicate that the most suitable particle size of the ore is -2 mm and calcination after grinding leads to the incomplete decomposition of the hydromagnesite ore. With an increase in calcination temperature and holding time, the loss on ignition of calcination and MgO grade of light-burned magnesia was higher until the calcination temperature is 900 degrees C for 3 h, after which the hydromagnesite ore was completely decomposed. At 800 degrees C, the gangue aragonite was completely decomposed. As the calcination temperature increased, the crystal form of periclase became perfect and the crystal grain size increased.

Automated summary

The most suitable particle size of the hydromagnesite ore for calcination is -2 mm, and complete decomposition of the ore can be achieved at a calcination temperature of 900 degrees C for 3 hours. Increasing the calcination temperature and holding time leads to higher loss on ignition and MgO grade of the light-burned magnesia. With the increase in temperature, the crystal form of periclase becomes perfect and the crystal grain size increases.