Three kaolin deposits in the Palaeocene Kerri-Kerri sandstone-dominated basin in northeastern Nigeria have been evaluated with respect to their particle size distribution (psd) and colour, and mineralogical and chemical compositions. The kaolin is fine-grained (≥ 80.75 wt % finer than 2 μm) and light grey to white. In terms of mineralogy, X-ray diffractograms show that the deposits are substantially rich in kaolinite and have subordinate amounts of quartz and illite whereas goethite, hematite and halloysite occur in trace amounts. CaO, Na2O and MgO concentrations are low (≥0.44 wt %) indicating that kaolinitisation resulted from weathering accompanied by leaching of the alkalis. This process resulted in complementary enrichment of SiO2 and Al2O3. Low Fe2O3 (≤ 1.20 wt %) as well as low MnO (≤0.03 wt %) makes the kaolin suitable for use in industrial applications in which colour in the end product is not desirable. With an estimated minimum reserve of 8.2 × 1010 tons, these deposits are economically viable pending further detailed investigations.
All Science Journal Classification (ASJC) codes
- Geochemistry and Petrology