Effect of B2O3 on degree of hematite crystallization during oxidation roasting
Adding B2O3 to the raw materials in the ball preparation process is beneficial for obtaining low melting point compounds,improving the ball strength,and reducing reduction swelling,thus enhancing the metallurgical performance.However,there is still a lack of in-depth research on the mechanism of how B2O3 affects the crystalli-zation and crystal continuity of hematite.Therefore,in order to understand the influence of B2O3 on the crystal con-tinuity and occurrence pattern of hematite,different proportions of B2O3 pure reagents were added to Fe3O4 pure re-agents.The mixture was then pressed,oxidized,and transformed into hematite,simulating the process of hematite formation in the roasting of magnetite pellets.SEM-EDS,XRD,XPS,and other methods were used to study the in-fluence of different B2O3 contents on the crystal continuity,crystal growth,and microstructure of hematite in the roasting pellets.Raman spectroscopy was used to analyze the effect of B2O3 on the crystal structure of hematite.Furthermore,the microstructure,crystallinity,and grain size were determined.Finally,the impact of different B2 O3 contents on the crystal continuity of hematite was discussed and summarized.The research results show that B2O3 has a promoting effect on the crystal continuity of hematite during the oxidation roasting process,followed by inhibitory effects.The proper addition of B2O3 can promote crystal growth and enhance the crystal continuity of hematite.When the mass percent of B2O3 is 6％and the roasting time is 40 minutes,the crystallinity of hematite is the best,reaching 83.68％.XPS analysis demonstrates that as the B2O3 content increases,the proportion of Fe3+in hematite gradually increases,with Fe3+accounting for up to 92.53％.As the B2O3 content further increases,the influence of B2O3 on slag fluidity and slag phase content increases.The slag phase infiltrates the hematite grains,in-hibiting grain growth and crystal continuity.Raman spectroscopy analysis of the hematite crystal structure reveals that with the increase in B2O3 content,the peak intensities of the LO mode and Eu mode of hematite increase,indica-ting an increase in symmetry disruption caused by lattice defects,higher crystal disorder,and corresponding higher defect content.
B2O3oxidizing roastinghematitedegree of crystallattice constant
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