Characterization of kaolin from Mankon, northwest Cameroon

Abstract

ABSTRACT A kaolin deposit from Mankon (northwest Cameroon) was prospected and studied for potential applications in ceramics. Six samples were investigated with X-ray diffraction (XRD), infrared (IR) spectroscopy and scanning electron microscopy (SEM) to determine the mineralogical composition and with X-ray fluorescence (XRF) to determine the chemical composition and properties for ceramic applications. The main minerals in the clays are kaolinite/halloysite and anatase associated with alunite, illite, gibbsite and maghemite. The kaolin samples have abundant organic matter (4–10%) and low absorption of methylene blue (0.2–2.5 meq/100 g), while SiO 2 (33.28–56.31%) and Al 2 O 3 (19.26–35.87%) are major oxides. The particle-size distribution derived from sieving and the hydrometer method indicates that 12–38% of the samples are in the <2 μm clay fraction. The clays have low to moderate plasticity (7–21%). One sample with K-feldspar and plagioclase displays the necessary properties for red ceramic products. SEM confirmed the occurence of halloysite in sample M9. The high kaolinite/halloysite content (64–97%), associated with low Fe 2 O 3 content (0.5–1.4%) demonstrates that five samples are suitable raw materials for white firing industrial kaolin.