Abstract
There are challenges being faced by ceramic manufacturers which one of them is to produce good quality ceramic tiles using the least expensive quality materials. To provide raw materials with quality and homogeneity that the present level of ceramic industry requires; it essentially involves performing profound research into existing raw materials and subsequently selecting those that represent the best qualities to be used be used in developing body formulas.
This study focuses on the mineralogical and chemical characterization of the 20 clays from the various regions of Sub-Saharan Southern West African. X-ray Fluorescence to analyse the chemical composition, X-ray Diffraction to analyse the structure of the crystalline materials, particle size distribution using the Sedigraph technique. Ceramics properties such as linear shrinkage, water absorption, green and dry strength, were also investigated by firing specimen clays at a temperature range of 1195 °C to determine their suitability for Ceramic Application for production of porcelain tiles.
Kaolinite, quartz, muscovite, plagioclase and microcline represent the dominant mineral phases, in addition to minor quantities of chlorite, smectite, and dolomite. The main oxides are SiO2, Al2O3, CaO, Na2O, K2O and Fe2O3. Once the characterisation of raw materials has been studied. The best performing raw materials were selected and used to produce the body formulations. It was important to take note that the body formulation depends on the type of tiles a company wants to produce. Irrespective of colour, tiles fall into two broad categories. Porous after firing (wall tiles, single and double firing) and zero porosity (floor tiles). Porous bodies contain calcium or magnesium compounds, so they develop new crystal phases during firing, and those crystals are responsible for mechanical strength. Usually, shrinkage is very low or zero, but porosity is higher than 10%. For vitrified bodies mechanical strength is a product of a glassy phase developing during firing (from feldspars). Shrinkage is usually higher than 5%. Red and white bodies can be of either type.
This study demonstrates that producing high-quality ceramic tiles using cost effective raw materials requires good understanding of the mineralogical and chemical characteristic of available clays. The 20 clay samples analysed using XRF, XRD and particle size distribution techniques the research identified the dominant minerals and oxides that influence their suitability for ceramic application. The presence of kaolinite,quartsz, muscovite, pagioclase and microline together with...