Warta Geologi, Vol. 46, No. 3, December 2020, pp. 214–219

Variation in textural properties of aplitic kaolin from
Kinta Valley

Khong Ling Han, Hareyani Zabidi*, Kamar Shah Ariffin

School of Material and Mineral Resources Engineering,
Engineering Campus,

Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang,
Malaysia

* Corresponding author email address:
srhareyani.zabidi@usm.my

Abstract:
Textural properties are among one of the fundamental characteristics
especially important to be understood before suitable application(s) of a
kaolin can be determined as they have direct influence on the other properties
such as plasticity, brightness, firing and rheological behavior. This paper
presents an investigation on the textural properties of aplitic kaolin from
Kinta Valley. Two degritted kaolin samples from different location of Kinta
Valley were measured for their particle size distribution by laser diffraction
method. The samples were then classified into different size fractions followed
by examination of their morphological property by various techniques which
X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and
field emission scanning electron microscope (FESEM). Generally, the kaolin can
be classified into two different types based on the fine fraction content which
may be consists of; i) delaminated platy kaolinite, or ii) tubular shaped
halloysite. These fine fractions however constitute only to minor amount or not
more than 12 % of the clays, as both clay consist predominantly of coarse book
like kaolinite stacks. The degree of crystallinity of kaolinite samples shows a
positive correlation to its particle size during examination by XRD, but FTIR
spectrum shows a high degree of crystallinity for all kaolinite samples
regardless of their particle size. Slight presence of halloysite is sufficient
to give an adverse effect on the clay crystallinity index measured from XRD
pattern. Sorting of the clay into different size and morphological fraction
creates a product with less variation in properties between individual
particles, and with more potential for tailoring or engineering of their
properties.

Keywords:
Kaolin, soft kaolin, kaolinite, halloysite, texture, textural properties,
crystallinity index

DOI :
https://doi.org/10.7186/wg463202008

ISSN
0126–5539; e-ISSN 2682-7549