ISIJ International
Online ISSN : 1347-5460
Print ISSN : 0915-1559
ISSN-L : 0915-1559
Fundamentals of High Temperature Processes
Effect of MgO and CaCO3 as Additives on the Reduction Roasting and Magnetic Separation of Beach Titanomagnetite Concentrate
Yongqiang ZhaoTichang SunHongyu ZhaoChengyan XuShichao Wu
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2019 Volume 59 Issue 6 Pages 981-987

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Abstract

To understand the effect of MgO as additive on the reduction roasting of beach titanomagnetite concentrate, the phase transformations, metallization degree and Fe–Mg–O phase diagram were studied in this paper. Results indicated that with the increasing of MgO dosage, more Mg2+ diffused into the magnetite lattice, replaced some of the Fe2+, and formed a large of MgFe2O4. So adding MgO not only did not effectively improve iron recovery, but baffled the reduction of iron oxides. Besides, the effect of CaCO3 on the growth of iron particles was also studied by optical microscope and Qwin image analysis software. Tests revealed that an appropriate CaCO3 dosage can facilitate the growth of iron particles. Because CaCO3 promoted the reaction of iron oxides, FeO content in the slag decreased and more nuclei of iron crystal was formed, resulting in the growth of iron particles. However, excessive CaCO3 increased the slag melting point, which hindered the diffusion and growth of iron particles. At last, the best product indexes were obtained by magnetic separation when CaCO3 dosage was 4%.

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© 2019 by The Iron and Steel Institute of Japan
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