Effect of firing on colour of clayey materials applied to traditional ceramics

Abstract

Increasing demand for use of clayey material in the traditional ceramic industry whereby clayey materials are fired at < 1300 oC, motivated this work, which focused on understanding the effect of firing on colour of clayey materials from Botswana, Mozambique, Pakistan, Senegal and the United States of America (USA). The colours of raw, fired, chemically bleached and magnetically separated clay samples were observed as one of the determining criterion for their suitability for use in the ceramics industry. Except for one sample obtained from South Africa, all the other samples of clayey materials were found to be suitable for the fabrication of fine and coarse ceramic products. However, other indicative tests such as particle size determination, mineralogical and chemical compositions, clay shrinkage as well as clay plasticity should be performed before a final decision on the use of the clayey material is reached at.


(Botswana Journal of Technology: 2003 12(1): 13-18)