COMPARATIVE ANALYSIS OF IMPORTED AND LOCALLY SOURCED GYPSUM FOR CEMENT PRODUCTION

Abstract: The availability and use of local gypsum for cement production have become imperative in the Nigerian cement industry. In this research, local and imported gypsum were analyzed comparatively using different characterization techniques: X-ray fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET). Dry and wet-beneficiation techniques were employed on different samples identified as Spain-A, Warake-B, Afuze-C, Avilele-D, Warake-B1, Afuze-C1 and Aviele-D1, respectively. The initial samples were crushed and sieved to 2 mm, and 500 g of each sample was heated to 45 °C for 24 hrs as dry-beneficiated. Three hundred grams (300 g) of each sample was then soaked for 24 hrs as wet-beneficiated. The dry and wet-beneficiated samples were further heated to 120 °C for 30 mins, and 10 g of each sample was ground and sieved to 45 µm for analysis. The XRF results showed improvement in the active component and SO3 purity of Warake gypsum, ranging from 72.26% and 86.93% to 75.45% and 91.59%, respectively, using wet- beneficiation. The various local gypsum samples had higher purity levels than Spain gypsum after wet-beneficiation. The FTIR analysis revealed the presence of different functional groups for all samples consisting of –COOH, −OR, CO−NH2, −C≡N, −OH, C=O, C−I, Br, F, C=C and −C≡C−, which are involved in ionic interaction with clinker mineral. BET analysis revealed improvement in surface area and pore size of 204.515 m2/g and 1.853 nm to 265.156 m2/g and 2.108 nm for Aviele wet-beneficiated gypsum. Investment cost analysis for local gypsum production revealed a profit of ₦ 25,104.20 when the cost of producing local gypsum is compared to the cost of importing Spain gypsum per ton, establishing the quality and potentials of different local gypsum for cement production in Nigeria.