A study of selected kenyan anthill clays for production of refractory materials

Abstract

Refractories are essential for all industrial processes using elevated temperatures. They play a triple role of providing mechanical strength, protection against corrosion and thermal insulation. The essential goal in the development of refractories is to obtain a useful lining life that will provide maximum furnace availability for the operators to meet production requirements at the lowest possible cost. High quality refractory at a cheaper cost is the main requirement. The aim of this study was to find out the possibility of using Kenyan anthill, as a major raw material in the production of refractory linings. Anthill clay has not been utilized in Kenya. Anthill clay was collected from Cheptebo, in the rift valley, crushed, sieved and the chemical composition determined. The samples were moulded into rectangular shaped bricks of 40mm height, 40mm width and 80mm length, allowed to dry and later fired up to a temperature of 10000c. Refractory properties like Compressive strength, Hardness, Linear shrinkage on firing, Apparent porosity and Density were determined. The result of chemical analysis indicated that the clay was composed of Silica (SiO2), 52.18%; Alumina (Al2O3), 15.79%; Iron Oxide (Fe2O3), 9.41%; Calcium Oxide (CaO), 4.30%; Potassium Oxide (K2O), 2.30%; Sodium Oxide (Na2O), 2.81%; and other traces. The chemical analysis suggests that the clay deposit is mainly made of kaolinite and free quartz. The physical and mechanical tests show that the bricks had Cold Crushing Strength of 6,019kPa, Hardness of 17.81GPa, Linear shrinkage of 8%, Apparent Porosity of 35.21% and Bulk Density of 2.46g/cm3. Anthill clay can make better local refractory raw materials.