Characteristics of Calcined Magnesite and Its Application in Oxidized Pellet Production

Calcined magnesite is a binding additive and an MgO-bearing flux for pellets production. The effects of calcination temperature and time on the characteristics of calcined magnesite were investigated. Experimental results indicated that the best calcination condition was 850 degrees C and 1 h. Under this condition, the hydration activity of the calcined magnesite was 80.56%, and the average diameter of crystal grain D, specific surface area S and the medium particle size D-50 were 25.4 nm, 45.40 m(2)/g and 3.41 mu m, respectively. This kind of calcined magnesite was a good binding additive for pellets production. At the same proportion of calcined magnesite, the effects of activities of calcined magnesite on metallurgical properties of green pellet and indurated pellet showed that calcined magnesite with high activity could improve the dropping strength and compressive strength of green pellet and enhance the burst temperature of green pellet; however, the effects of activity on compressive strength, low-temperature reduction degradation index, reduction swelling index and reduction index of indurated pellet were not obvious.