Abstract:
This research investigated the utilization of spent silica-alumina as filler for ceramics in place of pure alumina combined with ball clay (Mae san) and feldspar. Spent silica-alumina was obtained from the hydrogen peroxide industry. The experiments were performed in order to find the optimum conditions for the alumina earthenware manufacturing process by considering the physical properties of the test specimens, such as water adsorption, fired strength, green strength, shrinkage and density. The first experiment studied the effect to chemical composition by varying the spent silica-alumina/mixture ratio at 30 35 40 and45% (The mixture of ball clay and feldspar was fixed at a ball clay/feldspar ratios of 8:5 and a firing temperature of 1,180 ℃ (1453 K)). The second experiment studied the effects of the particle size of spent silica-alumina by varying the particle size of spent silica-alumina at 100, 150 and 200 mesh. The third experiment studied the effects of varying the firing temperatures at 900, 1000, 1100 and 1180℃(1173 1273 1379 and 1453 K). The fourth experiment studied the effects of varying the heating rate by increasing the rate by rates at 2, 3, 4 and 5℃/minute. The results indicated that the optimum conditions of the spent silica-alumina/mixture ratio, the particle size, the firing temperature and the heating rate for producing alumina earthenware ceramic were 40%, 100 mesh, 1100℃ (1373 K) and 3 ℃/minute, respectively. By using these conditions, the firing shrinkage was 11.42% fired density was 2 g/cm3, water adsorption was 11% and fired strength was 247.34 kg/cm2(24.25 MPa). The results indicated that leaching tests were all within the ceramic product standard limits. The result of X-Ray diffraction indicated that the test specimen has high hardness due to the high hardness phase of Corundum (AI2O3) was detected. However, the results did not detectedMullite (3AI2O3.2SiO2), high strength phase. The cost estimatuion of the reuse of spent silica-alumina as filler for ceramic revealed a cost of 94 bath/kilogram of produced ceramic material.