Effects of Bituminous Coal Ash Addition in Pottery Products

Abstract

Bituminous coal ash, fly ash (FA) and bottom ash (BA), from coal power plant were studied in this research for utilizations in ceramic and pottery industries. Both fly ash and bottom ash mixed with four different ball clays from two kinds of ceramic pottery products such as flowerpot and construction brick, Ratchaburi, Chantaburi, Angthong and Chonburi ball clay. The mixtures were varying ratio between ashes and clays depend on clay sources. After mixing, the bodies were formed to test pieces and were then fired at 800-1200 °C. The results indicated that, added fly ash 0-40 wt% significantly decreased water absorption and increased bending strength when fired at 1150 °C or above. For color effect, CIE L*a*b* color space, both fly ash and bottom ash revealed the samples less lightness, more red and yellow appearance. These results are obvious when fired at 1150oC or above. Following the results, fly ash is possible to be used in ceramic pottery industries replaced with other addition such as sand and pottery stone.