International Journal of Materials Science and Applications 2014; 3(5): 143-146 Published online September 10, 2014 (http://www.sciencepublishinggroup.com/j/ijmsa) doi: 10.11648/j.ijmsa.20140305.12 ISSN: 2327-2635 (Print); ISSN: 2327-2643 (Online) Influence of firing temperature on physical properties of Same clay and Pugu kaolin for ceramic tiles application Hashimu Hamisi 1, * , Seungyong Eugene Park 1 , Byung-Hyun Choi 2 , Yong-Taie An 2 , Lee Jeongin 2 1 Dept. of Materials Science and Engineering, The Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania 2 Electronic Ceramics Division, Korean Institute of Ceramic Engineering and Technology, Seoul, South Korea Email address: hamisih@nm-aist.ac.tz (H. Hamisi), eugene.park@ nm-aist.ac.tz (S. E. Park), bhchoi@kicet.re.kr (Byung-Hyun C.) To cite this article: Hashimu Hamisi, Seungyong Eugene Park, Byung-Hyun Choi, Yong-Taie An, Lee Jeongin. Influence of Firing Temperature on Physical Properties of Same Clay and Pugu Kaolin for Ceramic Tiles Application. International Journal of Materials Science and Applications. Vol. 3, No. 5, 2014, pp. 143-146. doi: 10.11648/j.ijmsa.20140305.12 Abstract: This study focuses on the effect of firing temperature on the physical properties of Same clay and Pugu kaolin for potential application in ceramic tiles. X-Ray diffractometer (XRD) is used to analyze the phases formed after firing. XRD result shows that quartz, sillimanite and cristobalite appears at temperature beyond 1200 o C while mullite phase develops in Pugu kaolin. Pugu kaolin shows low porosity (1.3%) at 1400 o C compared to that of Same clay (12.7%). Water absorption at 1200 o C is 7.8 % for Pugu kaolin and sharply reduced to 0.47% at a temperature between 1300 o C to 1400 o C suggesting complete sintering to have taken place at this temperature. Keywords: Clay, Ceramic Tile, Phase Development, Linear Shrinkage, Water Absorption 1. Introduction Clay is the main raw material in the traditional ceramic industry and an important ingredient in advanced ceramic products. For example, clay is used as a raw material in many industrial fields such as ceramics, paper and paint. Their applications are closely dependent on their structure, composition, and physical properties [1-4]. Ceramic tiles are composed essentially of clays and other inorganic raw materials such as quartz, feldspar, and carbonates, the clays being the most important raw materials. In fabrication of ceramic products, raw materials selection plays vital role in the final [1]. The physico-chemical properties of the resulting ceramics is influenced by the properties of the components present in the clay and the temperature they have been subjected to [5]. During firing, a series of transformation occurs which determines their final ceramic properties [6, 7]. Sintering of ceramic mass is fundamental in adjusting desired properties and occurs in general during liquid-phase formation. Thus the presence of components such as low-melting clays is very important. Fluxes (alkaline oxides, mainly K 2 O and Na 2 O), in reaction with silica and alumina, promote liquid phase formations that facilitate densification [8]. For the purpose of determining the quality of the clays used in the formulation of ceramic tiles, it is important to monitor and understand the phase transformations which take place during the firing process [9]. Tanzania is importing industrial scale ceramic tiles and most of other related ceramic products from outside the country, as they are not adequately produced locally. There are, however, abundant ceramic raw materials locally available that can be exploited and utilized for such ceramic application. Clay deposits have been reported in places like Singino-Lindi, Pugu-Dar Es Salaam, Malangali-Iringa, and Matamba-Mbeya, Same-Kilimamjaro, Arusha and Mwanza have been reported [10-12]. Basically the studies have been on geolological occurrence and suggestions on their possible use. Pugu deposit found to be with white kaolinitic sandstone [10]. Neither deposit has been studied for the use in the ceramic tile industry. Thus, the knowledge of these clays has both academic value and immediate commercial interest in the ceramic tile industry. This work is therefore to study the influence of firing temperature on physical properties of Same clay and Pugu kaolin for ceramic tile application. It focuses on the phase changes and microstructural development in relation to the physical properties due to change in firing temperature.