Determination of the Fe3+/ΣFe Ratio in Synthetic Lead Silicate Slags Using X-Band CW-EPR

• Published in: Journal of sustainable metallurgy Vol. 7; no. 2; pp. 519 - 536
• Main Authors: Cnockaert, Vincent, Bellemans, Inge, Crivits, Tijl, Vrielinck, Henk, Blanpain, Bart, Verbeken, Kim
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 2021; Springer Nature B.V
• Subjects: Continuous radiation; Earth and Environmental Science; Electron paramagnetic resonance; Environment; Freezing; Iron and steel making; Lead silicate; Metallic Materials; Mixed oxides; Oxidation; Process parameters; Research Article; Silicon dioxide; Slag; Superhigh frequencies; Sustainable Development; Valence; Lead silicate slag; Secondary smelting; X-band CW-EPR; Fe
• ISSN: 2199-3823; 2199-3831
• DOI: 10.1007/s40831-021-00348-0

The oxidation balance is arguably one of the most important parameters during pyrometallurgical processes. In many cases, iron is the most abundant multivalent element present in silicate slags. Within these molten oxide mixtures, the oxygen balance is dominated by the relative fractions of Fe 3+ and Fe 2+ present. Measuring the concentration of ferrous and ferric iron in quenched slags can provide useful information about the oxidation state of the liquid slag at the moment of freezing. These measurements are not always straightforward, especially in lead-rich slags, as present in modern secondary smelting processes. Building on previous work, this article aims towards a practical and reliable methodology for determining the Fe 3+ concentration in lead-rich silicate slags using continuous wave electron paramagnetic resonance (CW-EPR). The method is demonstrated for different Fe 3+ / Σ Fe ratios and a basic model is proposed that relates the slag composition to the EPR spectrum, optimized for a high-lead ternary PbO–SiO 2 –Fe 2 O 3 slag. Graphical Abstract