Reaction between CaO and Fe₃O₄ under CO–CO₂ Atmosphere at 800°C–1100°C

抄録

A considerable amount of works were focused on the formation mechanism of calcium ferrite phases during the iron ore sintering process, especially under various O₂ content atmospheres at temperatures higher than 1100°C. But little attention has been paid on reactions between CaO and iron oxides in CO–CO₂ atmospheres at lower temperatures. In this study, the solid state reaction mechanisms between CaO and Fe₃O₄ under CO–CO₂ atmospheres at 800°C–1100°C were revealed by using XRD, VSM, etc. The results indicated that Ca₂Fe₂O₅ was easily formed under 5–50 vol% CO/(CO+CO₂) atmosphere above 850°C via the reaction of 6CaO + 2Fe₃O₄ +CO₂ = 3Ca₂Fe₂O₅ + CO and the reaction would be promoted with increasing the roasting temperature. In the CO–CO₂ atmosphere, Fe₃O₄ is easily oxidized to Fe₂O₃ in the presence of CaO because CO₂ components act as oxidative medium for the oxidation of Fe²⁺ to Fe³⁺.