Effect of Iron Redox Ratio on the hue mechanism of CaO-SiO2-Al2O3-MgO Slag system

Abstract

Currently, the FINEX slag from the iron-making process is quenched with water and shows a glassy appearance. However, normal slag has a brown hue, but problematic slag has a black hue, which leads to a decrease in the utility of the slag in terms of recycling resources and a decrease in economic demand. In previous studies, it was reported that the charge state of iron ions in the glass system containing iron ions affects the color development behavior of the glass. Therefore, in this study, the color development behavior of the glassy slag was controlled by changing the charge state of iron ions by controlling the redox atmosphere. In addition, the mechanism affecting the color behavior was analyzed using UV/Vis/FTIR spectroscopy, and together with the chemical quantitative analysis, the Iron Redox Ratio value, which had a dominant influence on the color behavior, was calculated. As a result, as the content of Fe2O3 increased in the oxidizing atmosphere, the color development in the slag changed from black to brown, and the color development behavior by the iron redox ratio, which was applied only to existing glass materials, could be applied to glassy water quenching slag was confirmed.