Production of Dolomite Refractories

Dolomite, unlike magnesite, is widely distributed throughout the earth’s crust. Both as a brick and a ramming mix, dolomite products are being utilized in large quantities in steel industries. Dolomite can be used as a substitute for manganese in most parts of the furnaces. Difficulties arise, however, because high temperature calculation of dolomite does not yield a stable product, and dolomite suffers from serious limitations of “perishing” and “dusting” in the furnace. A number of investigations have been carried out to determine the cause of these defects. A.H.Jay has shown from X-rays examinations that “perishing” is due to the hydration of the small content of uncombed lime, present after calcinations; white “dusting” is due to the volume expansion accompanying the inversion of beta-dicalcium silicate, formed during calcinations, to gamma-dicalcium silicate. Jay’s work emphasized the necessity of stabilization of dolomite, before it can be successfully employed for refractory purposes.