Authors : Nguetnkam Jean Pierre , Ganwa Alembert Alexandre , Kamga Richard and Ekodeck Georges Emmanuel
Abstract: This research deals with mineralogical and geochemical studies of 4 kaolins from paleolake of Ngaoundere in order to investigate their composition (mineralogical composition, distribution of major, trace and rare earth elements) and to assess their source area composition. Methodologies based on the description of outcrops and boreholes, using X-Ray Diffraction (XRD), Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), Transmission Electron Microscopy equipped with an Energy Dispersive X-ray Spectrum (TEM -EDS) and chemical analyses allowed for the definition of 2 main groups of sedimentary kaolins within the paleolake. The first group occurs at the upper part of the paleolake and is characterized by relative high SiO2 and Al2O3, High (La/Yb)N, (Gd/yb)N ratios, high LILE, High La and low TiO2, Zr/Th, TTE and HFSE. These data indicate that the above mentioned kaolins were generated from an intense weathering of a granite source and transported and deposited in the actual paleolake. The second group occurs at the lower part of the paleolake and is characterized by relative high TiO2, TTE, HFSE, Zr/Th and relative low SiO2 and Al2O3, low (La/Yb)N, (Gd/yb)N ratios, low LILE and low La. These kaolins were generated by an intensive weathering of a mix granite/basalt composition source and also transported and deposited in the actual paleolake. Kaolinite is the predominant phyllosilicate, associated to minor amounts of quartz, goethite, anatase, illite, gibbsite and organic matter. Kaolins of the first group, due to their relative low iron mineral content (< 2.5) could be used in the ceramic industries, paper coating and pain. Industrial use of the kaolins of the second group requires a beneficiation step to remove iron mineral and organic matter.
Nguetnkam Jean Pierre , Ganwa Alembert Alexandre , Kamga Richard and Ekodeck Georges Emmanuel , 2007. Mineralogy, Geochemistry and Provenance of Kaolins from the Paleolake of Ngaoundere (Cameroon, Central Africa) . Journal of Engineering and Applied Sciences, 2: 1365-1376.