Preparing high-purity iron by direct reduction-smelting separation of ultra-high-grade iron concentrate

Feng Li¹，Qing-jie Zhao¹，Man-sheng Chu²，Jue Tang¹，Zheng-gen Liu¹，Jia-xin Wang¹，Sheng-kang Li¹

1. School of Metallurgy, Northeastern University2. State Key Laboratory of Rolling and Automation, Northeastern University

摘 要：A new process for preparing high-purity iron（HPI） was proposed, and it was investigated by laboratory experiments and pilot tests.The results show that under conditions of a reduced temperature of 1075°C, reduced time of 5 h, and Ca O content of 2.5 wt%, a DRI with a metallization rate of 96.5% was obtained through coal-based direct reduction of ultra-high-grade iron concentrate. Then, an HPI with a Fe purity of 99.95% and C, Si, Mn, and P contents as low as 0.0008 wt%, 0.0006 wt%, 0.0014 wt%, and 0.0015 wt%, respectively, was prepared by smelting separation of the DRI using a smelting temperature of 1625°C, smelting time of 45 min, and Ca O content of 9.3 wt%. The product of the pilot test with a scale of 0.01 Mt/a had a lower impurity content than the Chinese industry standard. An HPI with a Fe purity of 99.98 wt%can be produced through the direct reduction-smelting separation of ultra-high-grade iron concentrate at relatively low cost. The proposed process shows a promising prospect for application in the future.

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