Effect study of an amount of active alumina addition on the properties of alumina refractories with a complex additive of chromium oxide and zirconium dioxide

Abstract

An effect of active alumina amount introduced into a batch (7.5 - 22.0 %) on the properties of alumina samples containing a complex additive of chromium oxide (10 %) and zirconium dioxide (3 %) was studied. The optimal amount of introduced active alumina (12.5 %) was established, which ensures the production of samples fired at a temperature of 1580 ºС, with the lowest open porosity (18.2 %), the highest apparent density (3.25 g/cm3) and the highest cold crushing strength (117 N/mm2), refractoriness under a load of 0.2 N/mm2 > 1700 ºС, thermal shock resistance (in the mode of 1300 ºС — water) not less than 7 thermal cycles.The results of carried out studies were used in the development of production technology of domestic refractory products based on fused corundum, α-form alumina, active alumina, containing the complex addition of chromium oxide and zirconium dioxide, by semi-dry pressing method. These refractory products characterized by high properties and intended for service at a temperature of 1850 ºС in the combustion chamber of carbon black production reactors.The use of these refractories in the lining of above mentioned high-temperature industrial units will allow to increase a duration of their operation due to an increase in the refractory durability in service, as well as to save material and energy resources associated with a relining of the reactors.