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

The corrosion behavior between CaO-SiO 2 -Fe x O(-CaF 2 ) slag and novel microporous MgO at 1500 °C is investigated using the crucible method in this work, the effects of basicity ( R = CaO/SiO 2 ), FeO content, and CaF 2 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) 2 SiO 4 , 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 CaZrO 3 -ZrO 2 intergranular phase in microporous MgO is essential to inhibit the corrosion from the slag with 5 wt.% CaF 2 . The reduced penetration of CaF 2 -contained molten slag into microporous MgO is primarily attributed to the decrease in slag surface tension.