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.

Development of a Novel Flash Ironmaking Technology with Greatly Reduced Energy Consumption and CO2 Emissions

“…6 Models of silicate melt structural entities with their Q-notation, NBO/Si ratios, and structural units in addition to showing the bridging oxygen (BO) and nonbridging oxygen (NBO), respectively [6,57] were applied to slags of interest for the Flash Ironmaking Technology (FIT), especially in terms of the effects of water vapor expected to be present in high contents in the new process [6,[55][56][57][58]. Table 1 [6,54]. In addition, the XPS and the NBO/T suggest that the studied slag is more depolymerized under a CO/CO 2 atmosphere and more polymerized under the H 2 /H 2 O atmosphere [57].…”

Effect of Water Vapor on Sulfur Distribution Between Liquid Fe and MgO‐Saturated Slag Relevant to a Flash Ironmaking Technology

“…The effect of water on the slag chemistry was further investigated in this laboratory to understand the interactions at the molecular level. [4,5,16,17] The authors also found that water affected Flow rates are calculated at 25 8C and 0.85 atm (atmospheric pressure at Salt Lake City). www.steel-research.de the distribution of P and Mn between slag and molten iron.…”

Effects of Pre‐Reduction Degree of Ironsand on Slag Properties in Melting Separation Process

“…In this process, the more polymerized the melting slag is, the more Q n with high n is produced. As seen in Table , with slag PRD increasing, the area ratios of Q 0 and Q 1 decrease whereas the area ratios of Q 2 and Q 3 increase, leading to the increasing ψ ( ψ = ( Q 3 + Q 2 )/( Q 1 + Q 0 ), (a measure of polymerization degree) in the experimental scope. It also suggests FeO behaves as basic oxide because of the enhanced depolymerization effect on the silicon network structure with FeO increasing.…”

“…Thus, the spectrum must be deconvoluted. As Gaussian de‐convolution is widely used in silicate slag and provides good fitting results in the pre‐analysis of this work, Gaussian method is used to fit the curve and assign the individual vibrations of structural units qualitatively and quantificationally. The fitting process is firstly assumed Raman envelope according with the Gaussian distribution, and then new bands are added based on the distinguishable shoulders and peaks, as displayed in Figure b–f.…”