Abstract

In Nigeria, several additives usually used in blending fireclay are imported. Similarly, other materials in the country are currently underutilized. These materials could be used as additives to alter/improve the refractory properties of fireclay. The performance behavior of refractory bricks produced from single and multi-component blending of Osiele and Ikorodu fireclays with Azara-Lafia zircon was studied. The chemical compositions of the raw materials were determined using the Atomic Absorption Spectrophotometer (AAS-PG990AFG). The Osiele and Ikorodu fireclays were blended with Azara-Lafia zircon at varying mass proportions of 10 #x2013; 35%. The blended samples were mixed with water (3 #x2013; 4%), molded into bricks using the Hydraulic Press (Paul-Weber D-7084) to 300KN. The bricks were air dried for 24 hours and later fired in the Carbolite RHF-16/15 furnace at 800oC to 1200oC. Cold crushing strength test were conducted using Testometric M-500-30KN D7940. The results showed that Osiele clay and Ikorodu clay consist of 30 #x2013; 31% Al2O3 and 41 #x2013; 51% SiO2 which belongs to the alumino-silicate groups while the zirconia content in Azara-lafia is 65.3%. The bricks produced from Osiele clay and Ikorodu clay with no zircon additive has refractoriness values of 1500oC and 1400oC, thermal shock resistance of 20 and 24 cycles, compressive strength of 132KN/m2 and 108.4KN/m2 respectively. The refractoriness of the bricks produced from Osiele clay and Ikorodu clay with zircon additives of 10 #x2013; 35% has a constant value of 1300oC. The values of their fired linear shrinkage, loss on ignition, compressive strength and apparent porosity decreased linearly with increasing percentage of zircon. These bricks exhibited poor thermal shock resistance as they failed in the first cycle. The result shows that the Azara-Lafia zircon additives are found unsuitable as additive for production of high quality refractory bricks. However, these bricks can be used in lining of ovens, dryers and fu