Reaction sintering of dolomite with alumina forms MgAl_2O_4 and calcium aluminate phases depending upon the ratio of the reactants and temperature. The non-isothermal densification behavior of the composite powder was studied for the determination of sintering temperature. The phase formation, densification of the alumina-dolomite mixer as a function of temperature was studied. The co-grounded powder mixed with binder was formed to rectangular clots and sintered at 1550°C.The fired clot was crushed and grounded into different size fractions required for the refractory brick pressing. The properties e.g. porosity, density, crushing strength, hot modulus of rupture and thermal conductivity of the brick fired at 1520°C were determined. The porosity and pore size distribution and wetting behaviour of the refractories determine the extent of the molten aluminum contact and its infiltration. The Al resistance of the alumino-silicate and spinel-calcium aluminate bricks was tested against pure Al (A-7 grade) in the similar condition (850°C/72hrs). The spinel-calcium aluminate brick showed non wetting characteristics and no impurity pick up from the brick to the Aluminum metal after the corrosion test. Thermal spalling resistance and thermal expansion behavior of the brick were determined for the confirmation of application in the Aluminum Industry.
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