Influence of Fe₂O₃ on the Properties and Structure of Iron Coke

Iron cokes were produced in an electrical furnace from a coal blend containing varying levels of added Fe₂O₃. The effects of Fe₂O₃ on the properties and structure of the iron coke were then investigated using the coke for metallurgy determination of mechanical strength, determination of coke reactivity and coke strength after the reaction, X-ray diffraction, Raman spectroscopy, and a method for quantitative analysis of the minerals in coal and coke. Further, the relationships between the properties and structures of iron coke samples were established. The results show that the addition of Fe₂O₃ can reduce the tumble strength, coke strength after the reaction, aromaticity, microcrystalline size, graphitization degree, crystalline volume, and carbon order degree of the iron coke and increase the abrasion resistance, coke reactivity index, and pulverization rate. Moreover, the degree of influence increases with increasing levels of added Fe₂O₃. The Fe₂O₃ is mainly transformed into metallic iron during the coking process, and part of metallic iron is converted into Fe₃O₄ during iron coke gasification. With an increasing Fe₂O₃ content, the trend of the change in the minerals from Fe to Fe₃O₄ becomes much more obvious, resulting in deeper influences on the iron coke thermal properties. There are obvious correlations among the iron coke reactivity and iron coke strength after the reaction and the crystalline volume, carbon order degree, and metallic iron content. It is concluded that the addition of Fe₂O₃ decreases the crystalline volume and carbon order degree and increases the metallic iron content, resulting in increases in abrasion resistance and coke reactivity and decreases in tumble strength and coke strength after the reaction.