Research On The Viscosity Flow Of Containing Chromium Ti-bearing Blast Furnace And The Transformation Of Phase Crystallization

There are almost ten billion tons of vanadium-bearing titanomagnetiteinPanzhihua-Xichang area. The steel and vanadium production technology process hasbeen built during past40years, which consists of the mineral separation, blast furnaceprocess, vanadium extraction process in BOF, BOF steel making as well as continuouscasting. However, ironores in Hongge,whichhas the most abundant reserves in the fourmine areas in Panzhihua, was not utilized sufficientlyso far. The reason was that Honggemining containd0.49%~0.82%Cr2O3besides iron, titanium and vanadium elements.Cr2O3has a high melting temperature whichinfluences the blast furnace reduction andslagging process. Furthermore, the existence of Cr in hot metal has important effect onthe following vanadium extraction process in BOF. The research of the effect of Cr onthe blast furnace process is rarely reported. Therefore, the effect of Cron the blastfurnace was investigated systematically and roundlyin the present work, whichcontribute to the large-scale development and utilization of Hongge mining。The basic research on the sintering characteristics of Hongge iron ore was carriedoutin the present work. Hongge iron ore has the similar chemical and phase compositionwith vanadium-titanium iron concentrate ores except that it contains0.95%Cr2O3. Butthe particle sizes ofHongge iron ore were slightly bigger than that of vanadium-titaniumiron concentrate ores, which made them contain more particles that were not proper forgranulation. The wettability of Hongge iron ore is better than that of vanadium-titaniumiron. The moisture capacity and water absorption coefficient of Hongge iron ore werelarger. Based on the industrial sintering in Panzhihua iron and steel company, the basicsinter characteristics of Hongge iron ore were compared in the sintering with sameingredient and it can be found thatthe burning rate, yield,shatter strength and abrasionindexofHongge iron ore sinters decreased with the increasing basicity, but the verticalsinter speed productivity rate and tumbler strengthofHongge iron ore sinters increased with theincreasing basicity.The phase crystallization and transformation of the senary slag systems(CaO-SiO2-Al2O3-MgO-TiO2-Cr2O3) at constant CaO/SiO2of1.1in the process ofslowly cooling from1600°C to1000°C were theoretically calculated by the Factsagesoftware. The phasewith high melting point, including MgCr2O4、MgCrAlO4andMgAl2O4,can be found at1600°C with Cr2O3additions. The amount of Cr-Mg spinel phases and perovskite (CaTiO3) increased with the increasing addition of Cr2O3andbasicity. Additionally, the crystallization temperature of perovskite increased withincreasing Cr2O3and basicity. When the CaO/SiO2ratio increased from0.9to1.3at aconstant Cr2O3content, the crystallization temperature of perovskiteincreasedby90°C,resulting in the increase of the viscosity of the slag.Effect of Cr2O3and basicity(CaO/SiO2) on viscous behaviourofCaO-SiO2-MgO-TiO2-Al2O3slags (CaO/SiO2=0.9~1.3, Cr2O3=0~4mass%) wereinvestigated.It can be concluded that the viscosity of slag significantly increased withincreasing Cr2O3content, which was restrained in slags with high basicity. Asmallamount of Cr2O3was dissolved in Ti-bearing BF slag from the results calculated byFACTsage. However, MgCrAlO4was easily formed by Cr2O3、MgO and Al2O3. TheFTIR spectroscopic analysis of the structure of slag seems to suggest that Cr2O3slightlydepolymerized the slag and the increasing basicity could depolymerize the slag bymodifying the silicate structure of slag. Moreover, the viscosity of slag significantlyincreased with increasing basicity,resulting from the crystallizing of perovskite.