2013 Volume 53 Issue 9 Pages 1571-1579
Calcium hydroxide and Calcium carbonate were used as CaO source to investigate the formation behavior of calcium ferrite in solid state below 1200°C. The density change of CaO–Fe2O3 samples with temperature were in-situ and off-line determined, with linear shrinkage rate test for mixed powders at a heating rate of 10°C/min and with Archimedes method for the pellets isothermal roasted at various temperatures and time, respectively. Phase composition of roasted samples was determined with X-ray powder diffraction method, and TG-DSC analysis was used to understand the decomposition behavior and formation of calcium ferrites in different heating rates. As a result, the formation of Ca2Fe2O5 could occur much earlier when calcium hydroxide was used as raw material; however, the formation rates of CaFe2O4 tend to be faster when calcium carbonate was used when the temperature is higher than 1100°C. In addition, the formation of Ca2Fe2O5 was supposed to be prior to CaFe2O4 in this study when the temperature is lower than 900°C.