Study On Phase And Structure And Viscous Flow Characteristics Of Chromium-containing High Titanium Blast Furnace Slag

The Hongge Mine in Panzhihua-Xichang area is a typical high-chromium vanadium-titanium magnetite.The amount of ore mined in the Hongge mining area is1.829 billion tons.The content of Cr₂O₃ and valuable elements?such as Co,Cu,Ni?is higher than other mining areas.So,it has a high mining value.However,the mineral composition of the ore is Complex,difficult to use,and the presence of Cr₂O₃ has an impact on the smelting-reduction process and slagging process in the blast furnace.So far,researchers only did the preliminary exploration and focused on the ore phase composition and metallurgical analysis of the Hongge vanadium-titanium magnetite in the Panxi area.The development and utilization of Hongge Mine has not yet been carried out,and relevant basic research is also scarce.Therefore,a full understanding of the high temperature physical properties of titanium-containing blast furnace slag under high chromium conditions is of great significance for the large-scale development of Hongge vanadium-titanium magnetite.In this paper,the dissolution behavior of Cr₂O₃ in slag and the phase,structure and viscous flow properties of chromium-containing high-titanium blast furnace slag were studied by the combination of experiment and theory,and the following conclusions were drawn.?1?The study on the dissolution behavior of Cr₂O₃ in high titanium blast furnace slag:When the content of TiO₂ was fixed at 22wt.%,CaO/SiO₂ at 1.1,Cr₂O₃ was beyond 0.53wt.%,the perovskite phase was formed in the slag,which led to a significant decrease in the dissolution rate of Cr₂O_3.In order to improve the dissolution rate,the content of Cr₂O₃ should not exceed 0.53wt.%.The solubility of Cr₂O₃ in slag was less than 1wt.%with different TiO₂ content and basicity.?2?The study of the phase transition of slag:The spinel phase,perovskite phase,anorthite phase,and clinopyroxite phase were formed in the cooling process of the chrome-containing high-titanium blast furnace slag.With the increase of Cr₂O₃ content,the crystallization temperature of perovskite phase decreased first and then increased,the crystallization temperature of spinel increased.With the increase of TiO₂ content,the crystallization temperature of perovskite and spinel decreased.With the increase of CaO/SiO₂,the crystallization temperature of perovskite and spinel increased.?3?Study on the viscous flow properties of slag shown that:1)With the increased of Cr₂O₃ content,the viscosity decreased first and then increased,because the Cr₂O₃ in the melting slag can depolymerize the slag,which decreased the viscosity,and when the content of Cr₂O₃ was 1.5.wt.%and above,the crystallization of perovskite and spinel increased the viscosity.With the increase of Cr₂O₃ content,the melting temperature of slag decreased first and then increased.To make the slag have good fluidity and thermal stability,the content of Cr₂O₃ in slag should not exceed 0.5wt.%.2)With the increase of TiO₂ content,the viscosity decreased.It is because the Ti⁴⁺continuously detached from the network structure,the content of[Ti₂O₆]^4-decreased,and the content of[TiO₄]^4-tetrahedral monomer increased,which made the slag structure simplified.With the increase of TiO₂ content,the melting temperature of slag increased,the content of TiO₂ in slag should not exceed 26wt.%.3)With the increase of CaO/SiO₂,the viscosity decreased.This is because the increase in free oxygen ion content in the slag reduces the degree of polymerization of the slag.With the increase of CaO/SiO₂,the melting temperature of slag increased,the CaO/SiO₂ should not exceed 1.15.4)Having compared the experimental value and calculation value of visicosity,we found that the NPL model can predict the viscosity of CaO-SiO₂-Al₂O₃-MgO-TiO₂-Cr₂O₃ well,and the Maximum average error was 17.49%.