Evaluation of Dolomite for Production of Semi-Stabilized Dolomite Refractory Bricks

This work was carried out to investigate the suitability of dolomite rocks for the manufacture of dolomite refractory bricks. Preliminary tests have been done to determine the physical properties, chemical and mineralogical constitutions of raw materials ( dolomite serpentine and white kaolin ) to find their suitability for production of dolomite refractories bricks. These tests also refer to the softening point and residual carbon after firing of binding materials. Following the five components system ( CaO, MgO, SiO2, Fe2O3), ten refractory body mixtures were prepared with different amount of raw materials and firing at 1550 deg. The suitability of such mixtures for refractory bricks was ascertained by investigating the action of heat. Phase reaction and mineralogical changes that occurred in the fired mixture were studied by means of X-ray analysis. On the basis of physical properties chemical and mineralogical constitutions, two samples were selected for making semi-stable dolomite refractory bricks. Crushing, grinding and grain size distribution were carried out to prepare the clinker for making sample briquettes. Four different types of binders were used with the semi-stable dolomite sample. Standard samples have been prepared in the laboratory by using semi-dry pressing method. The molding pressure was 100 mN/M2. The samples were fired at 1450, 1500, 1550 and 1600 deg. The technological properties of selected samples were determined. The obtained results indicated that the investigated dolomite could be used as a source of raw material for the manufacture of semi-stable refractories, mainly required for steel and cement industries. ( Author's) 20 refs., 12 figs., 8 tabs