Mineralogical, Geochemical and Physico-Chemical Characterization of Clay Raw Materials from Three Clay Deposits in Northern Cameroon

The characterization of clay raw materials of three clay deposits from Northern Cameroon was investigated. The three deposits, located in Gaschiga, Sekandé and Boulgou, are locally used as building materials, but no data are available on these materials and they are relatively unknown. Mineralogical, geochemical and physico-chemical characteristics were studied, using X-ray diffraction, X-ray fluorescence and physico-chemical analyses. Mineralogically, quartz was the most abundant mineral in the studied raw materials. It is associated to abundant quantity of smectite, kaolinite and K-feldspars, and slightly abundant to traces of hematite and amphibole. Geochemically, those clayey soils are more siliceous (SiO2, 51% - 59%) with significant amount of aluminum (Al2O3, 15% - 19%) followed by iron oxides (Fe2O3, 3% - 10%). Other oxides (K2O, MgO, TiO2, Na2O, MnO, CaO and P2O5) are in relatively lower proportion. High level of silica content explains the sandy nature of these clays. The results of granulometric analysis show that the studied raw material contain sand (39% - 68%) as major grain size followed by clay particles (17% - 38%), silt (1% - 36%) and gravels (0% - 16%). The studied clayey soils were moderately plastic, with plasticity index values ranging from 13% to 30%, and are also characterized by very high liquidity limits of 34% - 63%.