No abstract

Palm oil fuel ash (POFA) is a by-product from thermal power plant where palm kernel, shell and fibre used as fuel to generate electricity and disposed with no economic value. POFA is used as quartz replacement in the production of porcelain. POFA was dried in an oven for 24 hours at 110 °C, ground at a speed of 250 rev/sec for 12 hrs. Some of the POFA amount was treated with 2 Molar of HCl acid and some was kept untreated. Both treated and untreated were substituted with quartz at 15 wt% and mixed with porcelain composition and dry pressed into pellets at a mould pressure of 91 MPa and sintered at 1150 °C, 1200 °C and 1250 °C for 2 hrs soaking time respectively. XRF revealed that, POFA has similar chemical composition with quartz. The highest compressive strength, bulk density and Vickers microhardness being achieved at sintering temperature of 1150 °C using treated sample with the values 169 MPa, 2.432 g/cm3 and 774 HV respectively. HCl treated POFA is a good candidate for quartz replacement and 1150 °C was the best sintering temperature.

Fly ash is alumina-silica waste products from the combustion of palm fiber and shells in the boiler which are collected at the multi-cyclone collectors where almost 3 million tonnes per annum being produced in palm oil industry in Malaysia. The aim of this paper is to investigate the replacement of feldspar by fly ash as potential fluxing agent in triaxial porcelain. Clay, feldspar, quartz and fly ash were mixed for 12 hours, pressed into pellets and sintered at 1250 ºC. The samples were measured according to the physical and mechanical properties. Microstructure study was done through SEM analysis. The optimum composition of fly ash was observed at 5 wt.% where the maximum compressive strength was achieved at 105.04 MPa and shows the decreasing results in volume shrinkage. SEM study shows intense interlocking between the primary and secondary mullite needles in glassy matrix which contribute in improving the strength of the porcelain at this composition. Therefore the substitution of fly ash is suitable as a fluxing agent in porcelain that improved its physical and mechanical properties.

This paper presents the study of the influence on the phase formation and strength of the porcelain by the partial substitution of fly ash. The fly ash was calcined at the temperature of 800 °C and partially substituted into feldspar. Each mixture were mixed and pressed into green pellets sintered at different sintering temperature (1100 – 1300 °C) at the interval of 50 °C for 120 min. The compressive strength, crystalline phase and the microstructure of the porcelain were investigated. The optimum physical and mechanical properties were obtained at 5 wt % of fly ash porcelain sintered at 1250 °C. The apparent porosity reaches a minimum value with 0.22 % which is nearly to zero and obtained the highest compressive strength of 105.40 MPa. The XRD results reveal that the highest percentage of mullite was obtained at the substitution of 5 wt % of fly ash with 49.0 %. The glassy phase shows an increasing trend with dissolution of mullite content which affects the strength and microstructure of the porcelain.

Palm oil fuels ash (POFA) is a by-product from palm oil industries that constitutes of different compounds such as silica (SiO2), alumina (Al2O3) and many others, its abundances and improper disposal in waterways and as a landfill cause environmental pollution and hence need for its modification and usage. This paper presents an alternative way of producing silica from POFA. Untreated POFA was dried in an oven for 24 hours at a temperature of 110 °C and ground in a ball mill machine for 12 hours at a speed of 250 rev/s. After sieving, the powder was dispersed in 1 mole, 2 mole and 3 mole of HCl. An increase in the composition of SiO2 was observed using X-ray Fluorescence (XRF) analysis due to the increase in the molarity of acid, X-ray Diffraction analysis (XRD) and Scanning Electron Microscopy (SEM) shows that POFA has a crystalline and porous cellular structure. This shows that acidic wash treatment is good and an improved method for the production of silica from POFA.