SYNTHESIS OF ALPHA-CORDIERITE (INDIALITE) FROM FLY-ASH

The high temperature hexagonal form of cordierite, indialite, has been synthesized using flyash as one of the starting raw materials. X-ray diffraction studies indicated the presence of only cordierite phase. T here were no detectable minor crystalline phases though mullite was pr esent in the starting flyash raw material. The properties of the synth esized material including thermal expansion compare well with the valu es of conventional cordierite. The presence of needles were observed w ithin the fine grained matrix in the microstructure.