Characterisation of Clay Deposits in Sokoto State for Potential Use in Refractory Brick Production

This study characterises clay deposits in Sokoto State, North West Nigeria, to assess their suitability for use in refractory brick production. Locally sourced refractory materials are critical for reducing the import dependence of Nigeria's metallurgical and ceramics industries, and the extensive clay deposits of the Sokoto sedimentary basin represent a potentially significant raw material base for indigenous refractory manufacture. Clay samples are collected from four deposit sites in Gwadabawa, Tangaza, Illela, and Binji Local Government Areas. Samples are characterised for chemical composition by XRF, mineralogy by XRD, particle size distribution by laser diffraction, plasticity index by Atterberg limits, and thermal behaviour by thermogravimetric analysis and differential thermal analysis. Selected samples are fabricated into bricks by semi-dry pressing and fired at 1000, 1200, and 1400 degrees Celsius. Fired properties evaluated include bulk density, apparent porosity, cold crushing strength, thermal shock resistance, and refractoriness. Findings indicate that samples from Gwadabawa and Illela have the highest alumina content (above 30 percent) and the lowest iron oxide impurity levels, qualifying as fireclay refractories. Fired specimens from these deposits achieve cold crushing strengths above 25 MPa at 1200 degrees Celsius firing, meeting ISO 1927 minimum requirements for shaped refractory products. Keywords: clay characterisation, refractory bricks, Sokoto State, fireclay, thermal properties.