RIETVELD QUANTITATIVE PHASE ANALYSIS OF NON- STOICHIOMETRIC CORDIERITE SYNTHESISED FROM MAINLY TALC AND KAOLIN: EFFECT OF SINTERING TEMPERATURE

Indialite or α-cordierite was synthesized by glass crystallization method using mainly talc and kaolin and with small amount of MgO, Al2O3, SiO2 to compensate the chemical formulation of non-stoihiometric compositions of cordierite. (3MgO.1.5Al2O3.5SiO2). B2O3, P2O5 and CaO was also added to decrease the melting and sintering temperature of cordierite. The glasses were pelletized and sintered from 850oC up to 1050oC. Phase compositions of both heat treated glass was quantified by X-ray powder diffraction data by the Rietveld method using TOPAS Ver 3 software. Result shows that about 60wt % of α cordierite has successfully crystallized at 850oC. Beside secondary phases (forsterite) which come from initial raw materials, phases from grinding media were also presents in the sample. The contamination was considered high since it has reacted with existence phases to form a new phase at higher temperature. Without any contamination from grinding it was expected to obtain more than 90wt % α cordierite using the same composition. ABSTRAK Indialite atau α-cordierite telah disintesiskan dengan kaedah penghabluran kaca menggunakan terutamanya talkum dan kaolin dan dengan jumlah kecil MgO, Al2O3, SiO2 untuk memampasi perumusan kimia tidak stoihiometric mengarang kordierit. (3MgO.1.5Al2O3.5SiO2). B2O3, P2O5 dan CaO turut menambah untuk susut meleburkan dan pensinteran suhu kordierit. Gelas-gelas itu adalah pelletized dan tersinter daripada 850oC sehingga 1050oC. Mengarang fasa kedua-dua memanaskan mengambil kaca dinyatakan kuantiti oleh pembelauan serbuk sinar X data oleh kaedah Rietveld menggunakan perisian TOPAS VER 3. Keputusan menunjukkan yang kira-kira 60wt % α cordierite telah dengan jayanya mengkristalkan d