Identification of Mixed-Layer Mineral of Cambodian Clays and their Phase Changes upon Firing

Abstract

Representative of clay deposits from central Cambodia were analyzed in terms of their mineral phases, mineralogical composition and phase changes after firing by qualitative and quantitative XRD analysis. To examine the phase changes, the samples were prepared and fired from 950 to 1200 °C. Results show that Cambodian clays contained quartz, illite, kaolinite, and chlorite-vermiculite mixed-layer as dominant mineral phases and the minor phases of albite and calcite also appeared in the samples. The rational analysis shows that chlorite-vermiculite was the main mineral in all Cambodian clays. After the samples were preceded upon firing, new phases of mullite, hematite and crystobalite were appeared above 1050 °C.