Abstract:
This research studied the utilization of a waste obtained from catalyst used in HDPE production as a white and opaque glaze raw material for ceramic products. The main chemical constituents of the waste are titanium dioxide, along with other oxides which were similar to raw materials used in white opaque glazes. The research was divided into two parts : the use of waste in raw glaze slip and the use of waste in frit preparation. Properties of the waste-containing glazes, i.e. melting behaviour, characteristic temperatures, hardness, chemical durability, abrasion resistance, thermal expansion and colours, were characterized. The purpose of the work was to replace the waste to expensive conventional titanium dioxide. As for the raw glaze slip, the pre-calcination process at 350 °C was required in order to remove chloride compound. A standard glaze was then prepared and compared with the waste-bearing glazes fired at 1200 °C. Formulation of the glaze recipe as well as the roles of raw materials in these glaze were determined. The work showed that the waste could substitute a conventional commercial grade titanium dioxide. The appropriate content of the waste to other materials for this in the glazes was up to 10 wt%, providing the white opaque glaze with whiteness value of 90 % and had similar properties to those of the standard glaze. For the frit, the waste could be employed without calcination. The melting temperature of the frit mixture were 1450 °C. Then, the frit containing were prepared, applied onto ceramic tiles and fired at 1120 °C. The properties of the frit itself as well as the frit glazes were also observed. The appropriate content of the waste in frit composition was around 10-15 wt% with whiteness value higher than 90 %. Therefore, the research works indicated that the waste derived from HDPE catalyst production was enable to be used as a substitute for raw material of the white opaque ceramic glazes.