PREPARATION OF CALCIUM SILICATE HYDRATE FROM THE CHAR OF HEAP FIRED RICE STRAW

Abstract

There is a pressmg need for developing countries to develop indigenous renewable energy sources which can make significant contribution to the economy and well being of their population. In the rural areas of these countries , the abi I ity to produce small amounts of mechanical or electrical power through the production of heat energy by utilizing locally available renewable fuels such as agricultural residues are extremely valuable and urgently required.

Firing of agricultural residues to produce heat energy leads to char production which is the firing residues.This char is a mixture of unburnt carbon, some metallic oxides and silicon dioxide. While the amount of silicon dioxide e present in the char is dependent upon the type of the agricultural residue, the

amount of unburnt carbon is determined by air availability and firing temperature.

Silicon dioxide present m the char is either crystalline or amorphous depending mainly upon the firing temperature of the agricultural residue.

A 1 iterature survey reveals that the char remained after firing agricultural residues can be used as a thermal insulation for steel works, constructive material for cement, ceramics, brick use and as a fertilizer for cultivated land use. Also it can be used after some treatment processes as a bonding agent and detergent use; for reinforced plastic and rubber use as well as for medicine I food industry use.

In view• of the crucial need to find more economical uses for the char remained after firing agricultural solid wastes, this research is conducted to utilize silica present in this char for preparing calcium silicate hydrate (CSH) which can be used as an adsorbent either alone or with the unburnt carbon present in the char to remove iron and manganese and other metallic ions from water.