Characterisation and Evaluation of Selected Kaolin Deposits in Kwara State for Furnace Lining Application

Abstract

This study evaluates the mineralogical, chemical, physical and thermal shrinkage characteristics of kaolin deposits in Kwara State, Nigeria. Sample were taken from Harmony, Kpandagari, Kutukpa, Share, and Gbaduwa site for suitability in furnace lining applications. The bulk density, porosity, moisture content, linear shrinkage and chemical composition investigations were performed using X-ray diffraction (XRD) and X-ray fluorescence (XRF) in accordance with ASTM standards. Results indicate that kaolinite and quartz are dominant in Kwara State with Harmony site having the highest feldspar content of between 30-35wt% and Gbaduwa with the lowest (25wt%). Gbaduwa also has the highest iron oxides concentration (S 3wt%). Kaolin primarily consists of kaolinite, but often contains impurities such as quartz, iron oxides, and organic matter, which can affect its properties. The highest bulk density of I .65 g/cm3 was observed at Kutukpa site which is suitable for refractory linings. The lower apparent porosity of Harmony (137%) and Kutukpa (119%) contrasts with Kpandagari's high porosity (276%), which provides thermal shock resistance. The specific gravity values ofKpandagari correlate with quartz and kaolinite contents, while low water absorption of Kutukpa suggests minimal impurities. Share sites exhibit low shrinkage, ensuring stable high-temperature performance in demanding environments. The results demonstrate that locally sourced kaolin possesses thermal and structural characteristics comparable to commercial insulating materials, indicating its strong potential for application in industrial thermal insulation systems such as furnaces and kilns.