Original Article

Corrosion behavior of microporous MgO in CaO-SiO₂-Fe_xO(-CaF₂) slags

¹ School of Metallurgy Engineering, Jiangsu University of Science and Technology, Zhangjiagang Jiangsu 215600, PR China
² State Key Laboratory of Advanced Refractories, Wuhan University of Science and Technology, Wuhan Hubei 430081, PR China

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Received: 25 April 2025
Accepted: 2 August 2025

Abstract

The corrosion behavior between CaO-SiO₂-Fe_xO(-CaF₂) slag and novel microporous MgO at 1500 °C is investigated using the crucible method in this work, the effects of basicity (R = CaO/SiO₂), FeO content, and CaF₂ content on the corrosion of microporous MgO by slag are examined. The microscopic interface between the molten slag and the microporous MgO is characterized using SEM-EDS, and the interfacial reaction mechanism is analyzed through the phase diagrams and thermodynamic calculations with FactSage software. The results show that compared to the slag with R = 1, the slag with R = 0.5 reacted with microporous MgO to form high-melting-point olivine phase (Mg,Fe)₂SiO₄, thereby inhibiting slag corrosion. The thickness of the (Mg,Fe)O solid solution layer at the interface gradually increases when the FeO content increases from 10 wt.% to 20 wt.%, thereby slowing down the slag corrosion. The CaZrO₃-ZrO₂ intergranular phase in microporous MgO is essential to inhibit the corrosion from the slag with 5 wt.% CaF₂. The reduced penetration of CaF₂-contained molten slag into microporous MgO is primarily attributed to the decrease in slag surface tension.