Characterization Of Cambodian Clays And Their Suitability For Ceramic Tiles Applications
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Date
2012-03
Authors
Bun, Kim Ngun
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
The present work is aimed to provide detail scientific data on characterization
of Cambodian clays and their suitability for ceramic tiles applications. The study
covered three parts – Part I deals with characterization of the properties of the raw
clay samples, Part II deals with investigation on changes of the properties between
bulk and clay fraction (< 2 μm), and Part III deals with optimization of ceramic tile
compositions incorporating Cambodian clays by using statistical design technique. In
Part I, the raw clay samples were characterized in terms of physical properties
(particle size distribution, cation exchange capacity, consistency limits), chemical
composition, mineralogical analysis, thermal property, and firing characteristics.
Some of these data were plotted on the reference diagrams to evaluate the suitability
of the Cambodian clays for various ceramic applications. In Part II, the bulk and clay
fraction samples were characterized on their physical properties chemical
composition, color of ceramic body after firing, transformation of phases after firing,
microstructure of ceramic bodies, and relationships within the firing characteristics.
Finally in Part III, the selected clay samples were mixed with the commercial
feldspar and silica to formulate the tile body. Ten formulations were designed by
using mixture experiment methodology. Regression models related to linear firing
shrinkage (LFS), water absorption (WA) and modulus of rupture (MOR) were
generated and analyzed. Results showed that the studied Cambodian clays present
very high plastic behavior. There major oxides such as SiO2 (51 – 57 %), Al2O3 (≈
22 %) and Fe2O3 (5 – 11 %) were observed in the clay samples. The main peaks from
the mineralogical analysis were assigned to quartz, chlorite-vermiculite mixed-layer,
illite and kaolinite. The evaluation diagrams illustrated that the Cambodian clays are
most suitable for structural ceramics. The clay fraction samples showed the
improvement of the specific surface area (SBET) and cation exchange capacity (CEC).
values. Differences of oxides contents were found between the bulk and clay fraction
samples. The oxides showing increment in the clay fractions are Al2O3, K2O, CaO
and MgO, whereas those showing decrement are SiO2 and Fe2O3. Firing at ≥ 1050 oC
led to the formation of new phases such as mullite and hematite for all the samples,
Description
Keywords
Scientific data on characterization of Cambodian clays , their suitability for ceramic tiles applications