The mechanism of preparation calcium ferrite from desulfurization gypsum produced in sintering

This work investigated the reaction mechanism of preparing calcium ferrite by using desulfurization gypsum from sintering. The influence of ambient conditions, morphology, and raw material ratio on the formation of calcium ferrite was also studied. The utilization rate of gypsum in sintering was calculated, and the results showed that gypsum decomposition was the limiting factor in the reaction mechanism of calcium ferrite synthesis, the optimal raw material ratio for the formation of calcium ferrite was 30.4% desulfurization gypsum produced in sintering, 31.7% iron ore, 11.1% blast furnace dust, and 26.8% graphite. The optimal reaction conditions were achieved by heating the powdered materials at 1150 °C for 4 h under blowing argon gas atmosphere, resulting in the final product with a gypsum desulfurization rate of 98.9%. When the sulfur content in the sinter increased by up to 5%, 99% of the gypsum could be recycled. When the sulfur content in the sinter was doubled, 19.45 kg of gypsum was consumed per ton of sinter produced.