Keywords: rice hulls, rice husks, amorphous silica, waste management, agricultural waste, rice residue, environmental protection, dilute organic acids, hydrochloric acid
Different methods to derive pure silica from agriculture waste
Rice residues are important natural resources, the management of these residues is a major challenge for environment protection. The use of different techniques to produce silica with minimal mineral contaminants having high Specific Surface Area (SSA) has been investigated. The different methods used depended on treatment of rice hulls with different dilute organic acids and hydrochloric acid, without the risk of using corrosive, toxic and hazardous substances in the burning process. Different powdered silica obtained are characterised by particle size distribution, crystallographic structure, BET SSA and chemical analysis. X–ray Diffraction patterns revealed the amorphous nature of silica. The major impurities of silica produced from rice hulls were Na, K and Ca salts.