Iron metal production in silicate melts through the direct reduction of Fe(II) by Ti(III), Cr(II), and Eu(II)

Abstract

The production of metallic iron in silicate melts by the chemical reactions, 2 Ti 3+ ( melt) + Fe 2+ ( melt) → 2 Ti 4+ ( melt) + Fe 0 ( crystal) 2 Cr 2+ ( melt) + Fe 2+ ( melt) → 2 Cr 3+ ( melt) + Fe 0 ( crystal) 2 Eu 2+ ( melt) + Fe 2+ ( melt) → 2 Eu 3+ ( melt) + Fe 0 ( crystal) has been demonstrated under experimental conditions in a simplified basaltic liquid, Such reactions may occur in lunar basalts and other reduced systems, and, thus, may aid in the understanding of the reduced nature of lunar basalts. The reactions were studied in a glass-forming Na-Ca-Mg-Al-silicate composition at a melt temperature of 1250°C and an imposed oxygen fugacity at the C/CO buffer (1 atm total pressure). Microtitrations of individually-doped samples were used in the quantitative assessment of their redox ratios and for the calibration of visible and near-infrared spectral absorptions. These spectral absorptions were then applied to the evaluation of the mutual redox interactions in dual-doped samples.