The experimental phase equilibria studies of the Fe–Sb–As system

Abstract

The Fe–Sb–As system is relevant to electronic components, semiconductors, superconductors, photonics, low- to high-grade minerals, slag, mine waste, and soil. Understanding its phase equilibria is mandatory for pyrometallurgical recycling from previously stated complex feedstocks and for advanced manufacturing applications. The phase equilibria of the Fe–Sb–As system were investigated. The goal of the study was to enhance and refine the prediction capability of the thermodynamic database applied for describing the multicomponent products in nonferrous and ferrous pyrometallurgy. This part of the project is intended for an accurate description of the Cu–Sb–Sn–Ni–S–Fe–As matte/speiss/liquid metal system. This database was embedded into FactSage software. Experiments were performed using the equilibration and quenching method, followed by direct examination of the quenched samples using electron probe microanalysis (EPMA). The solidus and liquidus projections were constructed, showing different primary phase fields including the liquid metal, BCC–Fe, hexagonal MeX = Fe_1+x(Sb, As), Fe(As, Sb), Fe(As, Sb)₂, Fe₂(As, Sb), MeX₂ (Me = Fe and X = Sb and As), and rhombohedral As–Sb solid solutions. No miscibility gap was observed. The hexagonal MeX = Fe_1+x(Sb, As) solid solution spans from As-free MeX (Fe_1+xSb) to Sb-free MeX (Fe₃As₂) solid solutions with a saddle (minimum or maximum) point at the liquidus and solidus projections. Four invariant reactions categorized as eutectic and quasi-peritectic types were identified.