Rice husks are agricultural biomass waste, which is considered as renewable resources that are produced every year in Ethiopia. Despite of its non-commercial value and causing environmental pollutions, its ash content is rich in silica (SiO2) and becomes an economic potential source. This study aims at utilizing this agricultural biomass waste into valuable product, silica. Silica (SiO2) was prepared by using rice husk ash (RHA) as a source of silicate (SiO-23) . Then further reaction of the ash with NaOH has formed Sodium silicate (Na2SiO3) solution. Then, titration of this solution with HCl forms the precipitation of silica-gel. The effect of acid pretreatment on the removal of metallic impurities and its percentage purity as well as on the properties of RHA was examined using Atomic Absorption Spectrophotometer (AAS).