Experimental and Computational Investigation of Slag–Refractory Interactions Under Conditions Relevant to Hydrogen Plasma Smelting Reduction

Abstract

Hydrogen plasma smelting reduction (HPSR) offers a potential one-step process for the reduction, melting, and refining of iron ores. So far, little is known about refractories compatible with the high FeO content of the HPSR slag during processing. This study presents a combined experimental and thermodynamic investigation of slag–refractory interactions in the HPSR. High-temperature refractory wear experiments and computational thermodynamics simulations were conducted to study interactions between HPSR slag and magnesia–carbon (MgO–C) refractory material. The refractory wear experiments were carried out in a chamber furnace according to technical specification CEN/TS 15418:2006, using synthetic slags. The refractory material was tested with slags of constant basicity (B2 = CaO/SiO2 = 3.5) and FeO contents varying from 10 to 28 wt% at 1600°C (1873 K). The slag infiltration ranged from approximately 1 to 10 mm depending on the iron oxide content of the slag. No substantial dissolution of periclase into the slag occurred, and the refractory structure remained intact in all tests. Experimental results confirmed that MgO–C performed well with all the tested slags and the thermodynamic simulations indicated that there was no significant driving force for direct dissolution.