Reaction between CaO and Fe3O4 under CO-CO2 atmosphere at 800°C-1 100°C

Abstract

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 1 100°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-1 100°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+.