Characteristics of silica rice husk ash from Mojogedang Karanganyar Indonesia

Indonesia is one of the countries in the world as the most abundant rice producer. Many researchers have demonstrated that the highest composition in the rice husk ash (RHA) is silica. Some of the advantages in utilizing silica as the raw material is the manufacture of ceramics, zeolite synthesis, fabrication of glass, electronic insulator materials, and as a catalyst. The amount of silica from rice husk ash is different for each region. Therefore, the study of silica from RHA is still promising, especially rice organic fertilizers. In this study, the rice came from Mojogedang Karanganyar Indonesia. Rice husk was dried under the solar radiation. Then the rice husk was heated in two steps: the first step at a temperature of 300 degrees C and the second step at a temperature of 1200 degrees C with a holding time at 2 h and 1 h, respectively. Furthermore, the temperature of the second step was varied at 1400 degrees C and 1600 degrees C. This heating process produced RHA. The content of RHA was observed on the EDAX spectrums while the morphology was observed from SEM images. The crystal structure of RHA was determined from XRD spectrums. The EDAX spectrums showed that RHA composition was dominated by elements Si and O for all the heating temperature. SEM images showed an agglomeration towards larger domains as heating temperatures increase. Analysis of XRD spectra is polycrystalline silica formed with the significant crystal orientation at 101, 102 and 200. The intensity of 101 increases significantly with increasing temperature. It is concluded that the crystal growth in the direction of 101 is preferred.