The Purification and Adaptation of Termite Hill Clay for Furnace Lining by Graphite and Rice Husk Addition

Abstract

This work has studied the possibility of purifying termite hill clay hydrometallurgically and subsequently adapting it for furnace lining by the addition of graphite and rice husk granules. A large quantity of termite hill clay was mined from a location on the campus of The Federal University of Technology, Akure (FUTA), Nigeria. The slurry obtained from the clay after washing in water was sundried for three days and again dried in the furnace at 90 °C for 8 hours. Representative samples were characterized via the X-ray diffraction (XRD) and scanning electron microscopy (SEM) in order to ascertain the relative abundance of the constituents of the clay. Subsequently, a substantial quantity of the clay was purified by leaching at a predetermined condition of; 1.6 mol/dm 3 of oxalic acid at 90 °C for 150 min. and 200 rev/min agitations. Cylindrical samples (5cm diameter by 5cm high) containing 5 % - 30 % of graphite and 1% - 5 % rice husk granules were prepared, dried at 110 °C and subsequently fired at 900°C, 1100°C, 1300°C and 1500 °C, at the rate of 4 °C/min and soaked for 2 hrs. These samples were subjected to different refractory tests (bulk density, cold crushing strength, permanent linear change, thermal shock resistance, refractoriness under load and apparent porosity). Results obtained showed that purified termite hill clay admixed with 15 % graphite and 3 % rice husk exhibited the desired properties of a good refractory material suitable for lining a rotary furnace.