| Summary: | Red clay from Ratchaburi province (Thailand), called Ratchaburi red clay (RRC), is normally used as a raw material for earthenware production in local industries. However, RRC is rarely used for producing red stoneware tiles due to firing temperature requirements. Present work aims to improve the properties of red stoneware tiles derived from RRC by the addition of iron oxide (Fe2O3). The samples composed of RRC, kaolin, and potassium feldspar with different contents of Fe2O3, were prepared by dry pressing method and fired at 1000–1200 °C. The water absorption and apparent porosity of samples decreased with increasing the content of Fe2O3 and firing temperature. Moreover, adding Fe2O3 up to a total content of 8.05 wt% not only enhanced the flexural strength and reduced the firing temperature but also reduced the water absorption to lower than 1.5% after firing at 1150 °C. Conversely, the flexural strength reduced when a total content of Fe2O3 up to 9.99 wt%. In addition, the evidence of excess Fe2O3 was observed in microstructure and XRD results.
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