MODULUS OF RAPTURE (MOR) OF PORCELAIN BY SUBSTITUTION OF QUARTZ WITH RICE HUSK ASH (RHA) AND PALM OIL FUEL ASH (POFA) AT DIFFERENT TEMPERATURES
This paper investigates to effects RHA and POFA in porcelain body as substitute materials for quartz. In order to collect experimental data, the effects of ground RHA and POFA replacement rate from 0 wt% up to 25 wt% in porcelain body was studied. The RHA and POFA were grounded in a ball mill until the median particle size was reduced to about 50 μm. They were used to substitute quartz in porcelain body from 0 wt% to 25 wt%. The mixed powder was pressed into pellets at mould pressure of 91 MPa. All the pellets were sintered at a temperatures of 1000 ºC, 1100 ºC, 1200 ºC and 1300 ºC for the soaking times of 2 hours. It was found out among other things that the Modulus of Rapture (MOR) of the samples increases with increase in substitution and also with the increase in temperature. With a value of 35 MPa the MOR of the samples containing 20 wt% sintered at a soaking time of 2 hours were higher than the standard porcelain. This could be attributed to the formation of larger amount of SiO2 glass, in the presence of fluxing components such as MgO, CaO and Na2O), more abundant in samples containing RHA and POFA.