The behaviour and reactions of sodium containing minerals in ash melting process

The flux effect of Na2O in synthetic ash samples has been experimented and explained. Based on the ash fusion temperature (AFT) tests, X-ray diffraction (XRD) and the Gibbs principle of minimum free energy, the behaviour and reactions of Anorthite (CaAl2Si2O8), Albite (NaAlSi3O8) and Nepheline (NaAlSiO4) have been studied to explain the flux effect of Na2O in this paper. The results show that the flux effect of Na2O is due to three reasons: the generation of low melting temperature minerals such as Albite and Nepheline; the reduction of a high melting temperature mineral Anorthite; and the most important one, the generation of eutectics formed by them will reduce the ash fusion temperature significantly.