ABSTRACT
This study is an experimental research on the possible use of rice husk ash silica for the Production of glass ceramics utilising the abundant agricultural waste. Rice husk was pre-treated, carbonised to drive out volatile matter and ash at 700oC. The brown ash (BA) obtained was characterised by X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD) to determine the chemical composition and to know the crystal phases present in the ash. The XRF result contained 79.98% SiO2 and the rest 20.02% included 1.80% P2O3, 0.42% Na2O, 1.54% CaO, 0.05% BaO, 0.11% TiO2. XRD result of the RHA showed a broad peak zone centred near 2θ 22.2o signifying the amorphous nature of silica. A solution of the ash was prepared with Sodium hydroxide, titre against a solution of Calcium trioxonitrate(iv) tetrahydrate and Trioxonitrate (v) acid, after some minutes the gel was formed and dried to powder. Fourteen samples were compacted and sintered at 700oC. The products were characterised by XRD, Scanning Electron Microscopy (SEM) and the physicochemical properties were tested. The XRD Pattern of the product showed the presence of sodium calcium silicate phase (Na4Ca4SiO6O18) combeite which belong to the bioactive ceramics family. The SEM showed a circular morphology of glass ceramics in glassy matrix with Energy Dispersive X-ray analysis (EDS) elemental spectra showing Si, Ca, P and Na.  Above all, a glass ceramics product has been produced highlighting the importance of utilising an agricultural waste RHA in the glass and glass ceramics industry for production. It also, goes to show that RHA is an alternative raw material to silica sand. The sol-gel route employed proves that it is a high energy saving technique when compared with the conventional methods and powder processing through sinter-crystallisation.