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 ti...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 CaO content of 2.5wt%,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 0.0008wt%,0.0006wt%,0.0014wt%,and 0.0015wt%,respectively,was prepared by smelting separation of the DRI using a smelting temperature of 1625°C,smelting time of 45 min,and CaO content of 9.3wt%.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 99.98wt%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.展开更多
Commercial pure iron billets having diameter of 60 mm and length of 180 mm were subjected to equal channel angular pressing（ECAP） at 350 ℃ for 1 to 4 passes via route Bc.Microstructural evolutions on three planes（...Commercial pure iron billets having diameter of 60 mm and length of 180 mm were subjected to equal channel angular pressing（ECAP） at 350 ℃ for 1 to 4 passes via route Bc.Microstructural evolutions on three planes（X,Y,Z planes） were characterized by optical microscopy and transmission electron microscopy（TEM）.It was found that after four passes an ultrafine microstructure could be formed on the X plane,but a band structure remained on the Z plane.Accordingly,the mechanical properties exhibited apparent dependence on the orientations.The strength in the x and y directions was higher than that in the z direction.The microstructural refinement and mechanical properties were discussed in terms of experimental results.展开更多
基金the National Natural Science Foundation of China(No.51904063)the Fundamental Research Funds for the Central Universities,China(Nos.N172503016,N172502005,and N172506011)the China Postdoctoral Science Foundation(No.2018M640259).
文摘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 CaO content of 2.5wt%,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 0.0008wt%,0.0006wt%,0.0014wt%,and 0.0015wt%,respectively,was prepared by smelting separation of the DRI using a smelting temperature of 1625°C,smelting time of 45 min,and CaO content of 9.3wt%.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 99.98wt%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.
基金Item Sponsored by National Natural Science Foundation of China(50971045)
文摘Commercial pure iron billets having diameter of 60 mm and length of 180 mm were subjected to equal channel angular pressing（ECAP） at 350 ℃ for 1 to 4 passes via route Bc.Microstructural evolutions on three planes（X,Y,Z planes） were characterized by optical microscopy and transmission electron microscopy（TEM）.It was found that after four passes an ultrafine microstructure could be formed on the X plane,but a band structure remained on the Z plane.Accordingly,the mechanical properties exhibited apparent dependence on the orientations.The strength in the x and y directions was higher than that in the z direction.The microstructural refinement and mechanical properties were discussed in terms of experimental results.
