Abstract
Abstract The influence mechanism of basicity on the reduction swelling index (RSI) of iron ore briquettes was investigated using the SEM analysis and Factsage 7.3 thermodynamic calculations based on the addition of pure CaO to Bayan Obo iron concentrate. The results revealed that the solid solution of Ca2+ in the FeO lattice increased with the basicity of the briquettes, whereas the diffusion channels of Fe2+ ions increased during the reduction process from FeO to Fe and resulted in the formation of a great number of slender and anisotropic iron whiskers, which consequently increased the RSI. Furthermore, the melting point of the slag phase decreased as the CaO content increased; this reduced its ability to resist the reduction swelling of iron oxides. When the basicity was increased from 0.3 to 0.8, the RSI reached a maximum of 69.85%. However, due to the saturated solid solution of Ca2+ in FeO lattice, as the basicity further increased from 0.8 to 1.2, excess CaO melting into the slag phase promoted the precipitation of spinel minerals with high melting points and difficult reduction properties. Thus, the diffusion of Fe2+ and the growth of the iron whiskers were hindered, and the RSI was reduced.
Highlights
Iron ore pellets are the key burden materials for blast furnace iron making due to their high grade and strength, uniform particle size, and convenient transportation andThis work is licensed under the Creative Commons Attribution 4.0194 Guo-Cheng Zhang et al.and suggested that an increase in the H2 content in the reducing atmosphere or an increase in the MgO and SiO2 content in the iron ore pellets assists in decreasing the reduction swelling index (RSI).Previous studies have illustrated that the reduction swelling indices (RSIs) can be decreased by increasing the basicity of iron ore pellets to an appropriate level
2400 0.2 0.4 0.6 0.8 1.0 1.2 Basicity further increase of basicity, a more liquid phase is produced in the briquettes, which destroys the stability of the overall structure of hematite
Different proportions of pure CaO were added to Bayan Obo iron ore concentrate to vary the basicity of iron ore briquettes
Summary
Iron ore pellets are the key burden materials for blast furnace iron making due to their high grade and strength, uniform particle size, and convenient transportation andThis work is licensed under the Creative Commons Attribution 4.0194 Guo-Cheng Zhang et al.and suggested that an increase in the H2 content in the reducing atmosphere or an increase in the MgO and SiO2 content in the iron ore pellets assists in decreasing the RSI.Previous studies have illustrated that the RSI can be decreased by increasing the basicity of iron ore pellets to an appropriate level. This study investigates the effect of basicity on the RSI of iron ore briquettes using Bayan Obo iron concentrate. This provides a theoretical basis for improving the reduction swelling properties of iron ore pellets and provides guidance regarding the production practices of fluxed pellets of Bayan Obo iron ore concentrate, which is of great significance for the efficient and appropriate exploitation and use of special mineral resources in China. The raw materials used in the experiment were Bayan Obo iron concentrate and pure CaO. By varying the ratios of pure CaO to Bayan Obo iron concentrate, the basicity of the briquettes was changed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
