Microwave-assisted metallurgy requires the use of high-quality refractory materialsRefractory materials that exhibit sufficient chemical stabilityChemical stability and transparency to microwaves at elevated temperatures. Corundum, mullite, periclase, and forsterite are the main phases with high melting points, all exhibiting relatively low microwave absorptivity. Their potential for use in microwave-assisted metallurgy can be evaluated by thermodynamic analysisThermodynamic analysis of their reactions with FeOFeO, a common component in various metallurgical processes. Corundum and mullite exhibit higher chemical stabilityChemical stability in air, while periclase and forsterite are less affected by FeOFeO in N2 and H2. Moreover, mullite exhibits the greatest microwave penetration depth (Dp) and minimal reflection loss (RL) from 25 to 900 °C, indicating its excellent microwave transparencyMicrowave transparency. These findings provide valuable insights for selecting appropriate refractory materialsRefractory materials for applications involving microwave energy.