Preliminary Investigations of Geochemical Characterization in Murunkan Clay Deposit, Sri Lanka
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Date
2020
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Uva Wellassa University of Sri Lanka
Abstract
Clay minerals are categorised into several groups as kaolin group, smectite group, illite
group, chlorite group and 2:1 clays such as attapulgite and sepiolite. Over other clays,
smectites are far more valuable due to their advanced application potential. Smectites
exhibit excellent swell properties and the highest cation exchange capacity (CEC).
Smectites can be used as adsorbents, filler material, drilling mud, excipients, and
plasticisers. Montmorillonite is a layered alumino silicate with a higher specific surface
area. It is also the most abundant of the smectite clays. The main objective of the current
study is to identify spatial and temporal variations in geochemical characteristics of the
Murunkan clay deposit. In this on-going project, two boreholes were drilled nearly 1 km
distance each other in the Murunkan Basin. One borehole reached a depth of 6.5 feet
while the other just passed a depth of 4.0 feet. Samples were cut into 5 inches of each
core. Geochemical characteristics of the Murunkan clay deposit were evaluated for 15
clay samples and a Sigma Aldrich montmorillonite sample (reference material) using Xray fluorescence (XRF), X-ray diffraction (XRD) and Fourier Transform Infra-Red
(FTIR) analyses. XRF results indicate ~57% SiO2, ~19% Na2O, ~10% Al2O3, ~5% Fe2O3,
~2% CaO, ~2% MgO, ~1.5% K2O, and ~1% TiO2. FTIR spectra of analysed clay samples
show transmittance bands matching with the standard data of kaolinite and
montmorillonite. Similarly, XRD analysis also suggests the occurrence of clay minerals
such as montmorillonite, illite, kaolinite, chlorite, muscovite and cookeite. Quartz and
feldspar can also be detected as the major impurities in the Murunkan clay samples.
However, no considerable spatial and temporal geochemical variations can be observed in
this deposit. Therefore, the Murunkan clay deposit can be identified as a prospective area
for further exploration. The future research works would focus to demarcate the boundary
of clay deposit and quantify the volumetric estimation. Besides, value additional potential
such as purification and possible industrial applications would be examined.
Keywords: Murunkan clay, Montmorillonite, Value addition potential
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Keywords
Materials Sciences, Mineral Sciences, Geochemical