Growth of spinel crystals in vanadium slag and their characterization

Abstract

Morphology of vanadium slags were investigated by scanning electron microscopy (SEM). The mineralogical phases were characterized by energy disperse X-ray spectrometry (EDS) and powder X-ray diffraction (XRD). The obtained results show that spinels and silicates are the major phases in the vanadium slag, and V is concentrated in FexV3-xO4 and Mgx(V, Ti)3-xO4. Both the spinel grain size and volume fraction in the slag with higher V2O3 content are much larger than that with lower V2O3 content. (Fe, Mn)2SiO4 and (Fe, Mn)SiO3 have a higher proportion in the slag with lower V2O3 and higher SiO 2 content. The relation among cooling conditions and grain size and volume fraction of spinels is also discussed. It is found that low cooling rate and long holding time benefit spinel crystal growth, especially for the interval of 1200-1250 °C. Both mean diameter and volume fraction of spinels could achieve or exceed the industry vanadium slag when holding more than 45 min. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.