Synthesis of ettringites using large-volume industrial wastes and their applications in solidification/stabilization of metal pollutants (Monex fly ash)

The synthesis of ettringite and arsenate and chromate substituted ettringite from pure chemicals and ettringite's reaction with selected metal pollutants have been investigated by various preparation techniques.; The large volume waste, Monex high performance fly ash, a kind of high-calcium fly ash which is typically cementitious, has been used in this study. The mixtures of Monex fly ash, gypsum and cement have been made according to the composition of ettringite. A set of samples has been made to investigate the optimum composition for ettringite formation. The investigation involving the S/S of arsenate and chromate using this mixture has been carried out. The NISCO fly ash as a substitute of calcium sulfate is mixed with Monex fly ash and cement to give ettringite.; Samples have been characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD) and Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS).