Investigation On Direct Reduction Of Iron Concentrate Powder From Bayan Obo And The Properties Of Melt-separation Slag

The valuable elements of bayan obo ore in the blast furnace smelting process can not be used effectively, so this article researched the direct reduction of iron ore concentrate and the molten separated slag.The studies showed that with the increasing of heat preservation temperature and holding time, metallization rate of sponge iron increase gradually. In the process of direct reduction iron ore concentrate, carbon gasification reaction was the restrictive link.The activation energy of reduction reaction of the ZhuDong iron ore concentrate was lower than BaRun iron ore concentrate.The experiment of the separation of slag and metal made the rare earth oxide gather together in the slag. XRD analysis results showed that the rare earth in the ZhuDong iron ore concentrate molten separated slag was La2O3and the rare earth in the BaRun iron ore concentrate molten separated slag was Ce7O12.The results showed that rare earth elements and silicon and calcium gather together through the scanning electron microscopy analysis and energy spectrum analysis for the molten separated slag.The molten separated slag of the ZhuDong iron concentrate of two kinds of different ferrous oxide content was tested respectively in a certain temperature keeping1.0hour and cooled down at the rate of1℃/min.The rare earth of the molten separated slag of high ferrous oxide content can gather together preferably in the process of heat preservation. The rare earth of the molten separated slag of low ferrous oxide content can gather together preferably in the process of cooling. This was related to the ferrous oxide content in slag.In the1350℃and1400℃, the rare earth enriched phase was block. In the1500℃, its existence form was long strip. The rare earth enriched phase of molten separated slag which was heated in1400℃was larger than one in1350℃,most of the phase is about5μm,and the phase is most in long strips when it was heated in1500℃,the width is3-5μm,and the length is about15μm. In the1400℃, the maximum mass fraction of the rare earth enriched phase was73%.In the1350℃, the minimum mass fraction of the rare earth enriched phase was64%.When the molten separated slag of low ferrous oxide content was cooled down at the rate of1℃/min, The existence form of the rare earth enriched phase was hexagon in the molten separated slag of low ferrous oxide content.