The Mechanisms Of Co-reduction Roasting Of Blast Furnace Dust And Titanomagnetite For Separation Titanium From Iron

Seaside titanomagnetite resources are rich in reserves.However,because of its compact structure,Fe and Ti in seaside titanomagnetite cannot be easily separated through the traditional beneficiation method.As shown by recent research,the direct reduction roasting-grinding-magnetic separation process can separate Fe and Ti in coastal ilmenite.The existing research used all different kinds of coal as the reducing agent,and the cost is high.Blast furnace dust,as a solid waste that is not utilized completely,mainly contains iron,carbon,as well as low amounts of silicon,aluminum,calcium,and magnesium.Every year,the blast furnace ironmaking industry in China will produce approximately 10 million tons of blast furnace dust.It is worth mentioning that only portions of blast furnace dust are used by returning sintering plants,while most domestic plants do not effectively use this material.Fixed carbon in blast furnace dust can replace coal to reduce iron from blast furnace dust and seaside titanomagnetite during direct reduction,because blast furnace dust contains a certain amount of fixed carbon,magnetite,and hematite.In this paper,the direct reduction process with blast furnace dust and seaside titanomagnetite is called co-reduction roasting process.This process is a new approach for highly effective utilization of blast furnace dust if its carbon and iron contents can be used fully in the co-reduction roasting.This paper studies blast furnace dust produced in three areas and a coastal ilmenite from Indonesia.The TFe grade of seaside titanomagnetite is 53.51%and the content of TiO2 is 11.26%.Besides,the TFe grade of blast furnace dust is 23%?36%and the content of fixed carbon is 18%?34%.Also,this paper studies the feasibility and influence law of co-reduction roasting-grinding-magnetic separation process of blast furnace dust and titanomagnetite,and obtains the optimal technological conditions.As revealed by the research results,co-reduction roasting-magnetic separation process of blast furnace dust and titanomagnetite can not only recover iron from blast furnace dust and titanomagnetite,but also obtain the reduced iron powder with 94.23%of TFe grade,0.58%of TiO2 content and 87.59%of the total iron recovery.According to the finding,blast furnace dust,as a reducing agent,can be reduced at the C/O molar ratio 0.72,which is verified through Jingtieshan iron ore.X ray diffraction,scanning electron microscope,and spectrum analysis are used to study the mechanism of co-reduction roasting process of blast furnace dust and titanomagnetite.As indicated by the research results,the co-reduction roasting-weak magnetic separation process by blast furnace dust and titanomagnetite can realize reduction at the C/O molar ratio 0.72.This is because the blast furnace dust can accelerate melting in the co-reduction process,inhibit the gasification reaction,promote solid-solid reduction reaction,and thereby enhance the utilization rate of fixed carbon.Additives are the key to the separation of Fe and Ti in titanomagnetite.During the co-reduction process of blast furnace dust and titanomagnetite,the reduced iron powder with good indexes can be obtained by adding a little fluorite.Due to the high contents of ash,aluminate,and silicate minerals in blast furnace dust,fluorite can fully and effectively reduce the slag melting point and viscosity.