Analysis of Slag Chemistry by FTIR‐RAS and Raman Spectroscopy: Effect of Water Vapor Content in H2H2OCOCO2 Mixtures Relevant to a Novel Green Ironmaking Technology

Abstract

In an effort to develop a novel green ironmaking process with the potential of steelmaking in a single continuous process the chemistry of selected slag systems were investigated. The novel process uses gaseous fuels and reductants that help reduce energy consumption and minimize greenhouse gas emissions. Amongst the proposed reductants and fuels are H2, natural gas (NG), and coal gas (CG). In different ironmaking processes, the molten bath (iron–slag bath) is expected to be at equilibrium with gas atmospheres of mainly H2/H2O, and CO/CO2/H2/H2O corresponding to the use of H2 and NG/CG, respectively. CO/CO2 gas mixture was studied for comparison. Based on the FTIR‐RAS (reflection absorption spectroscopy) and Raman analyses, it is expected that H2O stabilizes the more polymerized silicates anions rather than the depolymerized monomers. For the investigated slag compositions, slags under H2 and NG/CG at 1550 °C had values of ψ = (Q0 + Q1)/(Q2 + Q3) (a measure of depolymerization) 75 and 55 less than slags under the CO/CO2 atmosphere. It was concluded that the higher the water content in the gas atmosphere the more polymerized the silicates in the slag. The results of this study will, for the first time, provide new insights into the slag chemistry under H2O containing atmospheres.