RICE HUSK ASH (RHA) AND PALM OIL FUEL ASH (POFA) AND SOAKING TIMES: ANALYSIS OF COMPRESSIVE STRENGTH OF PORCELAIN CERAMICS
Rice husk ash (RHA) and palm oil fuel ash (POFA) is a by-product from agricultural waste produced thousand tonnes every year. This paper presents the use of RHA and POFA as a substitute material for quartz in fabricating an improved porcelain ceramic. The RH was thoroughly washed with distilled water in order to remove adhering soil and dust. After that it was dried in an oven at 100 ºC for 24 hours. Then the dried husk was subjected to the chemical treatment; 2M HCL, 5% solid at 25 ºC before calcinations to increase silica content. Untreated POFA was dried in an oven at 100 ºC for 24 h. It was ground in a ball mill for 1.5 h with the revolution rate of 200 rev/min to reduce the particle size. Untreated POFA was sieved to remove the particles coarser than 50 µm. The POFA was treated by heating it at a temperature of 600 ºC for 1.5 h. The mixed powder was then pressed into pellets at mould pressure (MP) 91 MPa. All the pellets were sintered at the temperature of 1100 ºC for 1 h hour, 2 h hour s and 3 h hours soaking times. It was found that the highest compressive strength occurred at 20 wt% RHA and POFA and a soaking time of 2 h. The increment in the strength could be attributed to the changes in the increase in mullite and critobalite.