Determination of Vanadium Oxidation States in CaO-MgO-Al2O3-SiO2-VO x System by K Edge XANES Method.

The oxidation states of vanadium in the CaO-MgO-Al2O3-SiO2-VO x slag system are investigated with the initial V2O5 concentration in the range of 1-10 mole fraction, in the temperature range, 1823-1923 K, partial pressures of oxygen from 10−5 to 103 Pa, and with the basicities in the range of 0.85-2.20. The valance states of vanadium are determined by the X-Ray Absorption Near-Edge Structure (XANES) method. The results indicates that, for the oxide VO x, at a given temperature, and basicity, x is found to increase slightly with increase of initial V2O5 concentration. With the increase of slag basicity, x is increased. It is also found that x in VO x decreases with the increase of temperature, whereas, at constant basicity, the value of x increases with the increased oxygen partial pressure. The present results are useful in the quantification of V3+/V4+ and V4+/V5+ ratios for a given slag as functions of basicity, temperature, and oxygen partial pressure. [ABSTRACT FROM AUTHOR]