Abstract
In this paper, the process of direct reduction roasting using magnetic separation to produce direct reduction iron (DRI) from high-phosphorus oolitic hematite, using coal slime and blast furnace dust as reductant, is investigated. The possible use of slime coal and blast furnace dust as reductant and the dephosphorization behavior during the process of direct reduction was studied. Experimental results showed that both blast furnace dust and coal slime can be used as reductant under certain conditions in the process. The dephosphorization mechanism of blast furnace dust and coal slime were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM)-energy dispersive X-ray spectroscopy (EDS). A DRI with 91.88 wt. % iron grade, 88.38% iron recovery and 0.072 wt. % P can be obtained with 30 wt. % blast furnace dust as reductant. The program not only used blast furnace dust but also recovered iron from blast furnace dust and high-phosphorus oolitic hematite. The analysis results revealed that phosphorus is distributed in gangue mineral and fluorapatite when blast furnace dust is used as reductant. Phosphorus-bearing minerals were not reduced to phosphorus element when the blast furnace dust was the reductant, but part of the fluorapatite reduced to phosphorus which smelt into metallic iron with coal slime as reductant. This led to a high phosphorus content of DRI. This research could provide support to the idea concept for recycling of carbon-containing solid waste and to assist the effective recovery of refractory iron ore by direct reduction–magnetic separation.
Highlights
Heavy dependence upon imported iron ore concentrates is one of the most significant challenges for China’s pyrometallurgical industry
In China, high-phosphorus oolitic hematite constitutes approximately 11.1% of iron reserves, the application of recovering these refractory ores can be considered based on current situation [1]
The reductant dosages were 20 wt. % and 30 wt. %. Respectively, and these dosages referred to the weight ratio of the raw iron ore. 20 g of raw iron ore was thoroughly mixed with a different dosage reductant and an identical amount of the additives
Summary
Heavy dependence upon imported iron ore concentrates is one of the most significant challenges for China’s pyrometallurgical industry. In China, high-phosphorus oolitic hematite constitutes approximately 11.1% of iron reserves, the application of recovering these refractory ores can be considered based on current situation [1]. The intimately intermixed structural unit of both fluorapatite and chamosite in high-phosphorus oolitic hematite have caused huge difficulties in obtaining the qualified iron ore concentrates by conventional methods of mineral processing [2,3]. A coal-based direct reduction roasting process combined with magnetic separation operation [4,5,6,7]. Metals 2018, 8, 897 as reductant to treat the refractory ore in recent years In this process, the iron oxide is first reduced to a metallic iron in the roasted products known as briquettes. The briquettes are ground and concentrated by magnetic separation to obtain direct reduction iron (DRI). It is well known that the phosphorus content of the feed stock for steelmaking must be strictly controlled because too high phosphorus content will cause cold brittleness and reduce the ductility brittleness of steel [8,9,10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
