Rice husks are agricultural biomass waste, which is considered as renewable resources thatrnare produced every year in Ethiopia. Despite of its non-commercial value and causingrnenvironmental pollutions, its ash content is rich in silica (SiO2) and becomes an economicrnpotential source. This study aims at utilizing this agricultural biomass waste into valuablernproduct, silica. Silica (SiO2) was prepared by using rice husk ash (RHA) as a source ofrnsilicate (SiOrn-2rn3) . Then further reaction of the ash with NaOH has formed Sodium silicate rn(Na2SiO3) solution. Then, titration of this solution with HCl forms the precipitation of silicagel.rnTherneffectrnofrnacidrnpretreatmentrnonrnthernremovalrnofrnmetallicrnimpuritiesrnandrnitsrnpercentagernrnpurityrnrnas well as on the properties of RHA was examined using Atomic AbsorptionrnSpectrophotometer (AAS). The percentage purity of SiO2 in the untreated RH were foundrn87.1% with some metallic impurities and 97.6% purity of silica is obtained from the treatedrnRH, which proved to be effective in removing the metallic impurities to a very lower levelrnand enhance the purity of silica in the RHA. The experiment and statistical analysis for thernproduction of SiO2 were designed using three-level-three-factor BBD for the total run of 17rnexperiments at operating process conditions of acid concentration (1-2N), pyrolysisrntemperature (450-850ï‚°C) and Pyrolysis time (1-5h). The optimal %yield were found to bern98.971% with 98.6% purity of SiO2% at conditions for 1.95N pretreatment acidrnconcentration,658ï‚°C pyrolysis temperature, and 4.95h pyrolysis time. The effects ofrncombustion temperature and time on % yield and the structural properties of silica in the ashrnwere also characterized using XRD and FTIR analysis. The quality of the extracted silicarnwere determined and characterized by its physico chemical properties. Furthermore, the silicarnobtained from RH was compared with the commercial silica. As a result, they performrnequivalency with commercially available. Also, from optimized conditions, surface area ofrnthe synthesized silica was found 779.7mrn2rn/g in amorphous form.