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India generates more than 14-million tones of rice husk each year. Burning it as a fuel is wasteful as well as leading to enormous air pollution. Its low sugar and cellulose content makes it unsuitable as a cattle feed, but Indian industrialists have now developed many uses for this waste product. A report from Radhakrishna Rao.
Significantly, among the different types of biomasses used for gasification, rice husk boasts a high energy content. Its high silica content - in excess of 80 per cent - makes it an economical source for producing silica, which is normally derived from sand. Silica extraction from sand, however, is both an energy intensive and costly process.
Not surprisingly, then, the technology developed by a team of researchers from the Aerospace Engineering Department of the Indian Institute of Science(IISc), in Bangalore, has been found to be an economically viable and environmentally friendly pathway to extract silica which is widely used in rubber production as well as the pharmaceutical, food and paint industries.
"Indian Space Research Organisation (ISRO) had earlier attempted a similar extraction method a few years ago. But ours is a totally eco friendly process with all the chemicals getting regenerated," says Prof.H.S. Mukunda, of the Aerospace Engineering Department of IISC and the Chief Executive of Advanced Bioresource Energy Technologies Society (ABETS).
ABETS is currently engaged in installing a 20-tonne plant to extract silica from rice husk ash in the south Indian state of Andhra Pradesh. The Silica Precipitation Technology of ABETS is an innovative system where...