(Indian Institute of Science Precipitated Silica Technology)


Rice husk is an agricultural residue abundantly available in rice producing countries. The annual rice husk produce in India amounts is generally approximately 12 million tons. Rice husk is generally not recommended as cattle feed since its cellulose and other sugar contents are low. Furfural and rice bran oil are extracted from rice husk. Industries use rice husk as fuel in boilers and for power generation. Among the different types of biomass used for gasification, rice husk has a high ash content varying from 18 – 20 %. Silica is the major constituent of rice husk ash and the following tables gives typical composition of rice husk and rice husk ash. With such a large ash content and silica content in the ash it becomes economical to extract silica from the ash, which has wide market and also takes care of ash disposal.


The silica precipitation technology developed at CGPL, Indian Institute of Science, Bangalore is a novel method for silica precipitation where the chemicals used are regenerated making it a closed loop operation. Successful studies for extraction of silica on laboratory scale which meet the industrial requirements have been carried out. Also studies are being carried out for suitable application of the undigested ash obtained after extraction, in water treatment plants with or without further improving the activated carbon content of the ash. 70 % conversion is achieved on ash basis and around 90 – 95 % on silica in ash basis.

Precipitated Silica from Rice Husk Ash IPSIT (PDF)      

Licensee For Precipitaed Silica:

USHER AGRO LIMITED [Not Functioning]
Regd Office :212. Laxmi Plaza ,
Laxmi Industrial Estate, New Link Road
Andheri (West) , Mumbai- 400 053

Tel:  +91 22 30681174
Fax: +91 22 30681177



Biosilica Company Ltd.
2-38-18-311 Nagatahigashi, Minami-Ku
Yokohama city, Kanagawa, PREF
Japan 232-0072
Tel : 0081-45-714-0866

Contact Person:
Bikas Bose
Cell no:+91-9830068981