An Analysis Upon Characterization of Fly Ash and Ultramarine Pigments: Synthesis and Characterization of Ultramarine Pigments from Coal Fly Ash

Abstract

This paper for the first time reports the conversion ofcoal fly ash into intense blue ultramarine via thiocyanate aluminosilicatesodaliteNa8[AlSiO4]6(SCN)2. The possibility of stepwise and systemic conversion ofthiocyanate aluminosilicatesodalite into intense blue ultramarine had neverbeen previously demonstrated. The ultramarine analogs of various colors havebeen prepared by structure conversion of thiocyanate aluminosilicatesodalite bycalcinations (500–950°C). The products obtained are characterized by variousinvestigative techniques including Fourier transform infrared spectroscopy(FT-IR), Raman spectroscopy, X-ray diffraction (XRD), UV visible spectroscopy,scanning electron microscopy (SEM), electron spin resonance (ESR) spectroscopy.Surface morphology is studied by the SEM technique. These extensivecharacterizations showed that the ultramarine pigment is good enough and thatthe sodalite framework is thermally highly stable with its structureundisturbed even at 950°C.