Bulletin of the Geological Society of Malaysia, Volume 54, November 2008, pp. 9 – 16
School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Malaysia
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Abstract — The chemical, mineralogical and textural characteristics of the Lampas kaolin occurrence, near Simpang Pulai Ipoh and its genesis were investigated using X-ray diffraction, scanning electron microscopy and differential thermal, thermo gravimetric, Fourier transform infra-red, X-ray fluorescence, energy dispersive X-ray and granulometric analyses. Properties including particle sizes, moisture content, LOI, chemical composition, plasticity, firing shrinkage, brightness/whiteness and modulus of rupture were used to evaluate its potential as an industrial raw material.
Field evidence supported by mineralogical and chemical analyses suggests that the Lampas kaolin is a product of both hydrothermal alteration and weathering of aplite, leucomicrogranite, pegmatites and medium to coarse-grained porphyritic granite. Numerous quartz-feldspar veins and stockworks, silicification and illite alteration (argillic zone) were evident and characterize the hydrothermal fluid influx system of the area. Kaolinite is the predominant clay mineral of the Lampas kaolin with subordinate quartz, feldspar and illite/muscovite. There is localized occurrence of halloysite. Widespread occurrence of red, orange, or brown more stable lateritic clay saprolite characterizes the near surface overburden. The alumina content of Lampas kaolin is generally between 28 and 34%. Impurities, particularly iron oxide is less than 0.2% and total alkali and titania account for less than 1%. The average total alkali and iron contents are about 0.7% and 0.2% respectively. The average dry powder moisture and LOI is 1.25% and 14.0% respectively. The shrinkage and modulus of rupture values of the Lampas crude clay are moderate at lower temperatures, mainly due to its lower alkali and iron contents with over 45% (D45) below the 2μm fraction and has excellent whiteness/brightness but with a lacking workability index.
Keywords: Kaolin, clay mineral, industrial clay, kaolinite, clay genesis