BIOSILICA FROM RICE HUSK ASH AS A NEW ENGINEERING RAW MATERIAL IN NIGERIA (original) (raw)

The paper aimed at presenting an overview of the potentials of biosilica (silica from rice husk) as a new engineering raw material in Nigeria. A study of a large volume of literature on generation of rice husk and its combustion using different types of equipment has been presented. Nigeria is currently the highest rice producer in West Africa, producing an average of 3.2 million tons of paddy rice or 2.0 million tons of milled rice. Rice husk makes up 20% of paddy, therefore Nigeria has the potential to produce about 400,000 tones of rice husks annually. Biosilica is produced from rice husk through chemical and thermal extraction processes. The silica in the ash undergoes structural transformations depending on conditions (time, temperature etc) of combustion. At temperatures of 500-800oC amorphous ash is formed and at temperatures greater than this (>800°C) crystalline ash is formed. The desirable physicochemical and mechanical properties of amorphous silica, notably their high reactivity, excellent binding properties, relatively high purity and excellent mechanical strength makes biosilica a prospective raw material in a wide range of technologies. Silica from rice husk can be used as a pozzalanic material in building industry, as a catalyst in chemical industries, as a material for making glass, and as a material for the production of solar cells in Nigeria.