Study On Electrical Conductivity And Structure Of High Titania Slag

Under the stimulation of rapid development in the fields of air space and chemical industries et al,products related to titanium has received increasing attention for its excellent comprehensive properties in recent years.With the natural rutile worldwide going to run out,the Ilmenite that shares a relatively abundant reservation gradually becomes the primary raw material to meet the needs of titanium industries in titanium dioxide pigment and sponge titanium production.Among the methods of fabricating titanium-rich material,the carbothermic reduction and subsequent smelting in EAF is the dominant process throughout the world.Although China has so far mastered some of critical techniques in the past several decades through importing advanced smelting techniques,the current high titanium production fails to satisfy the development requirements as a result of backward technical process.This fact is a huge challenge for the further improvement in terms of production,teaching and research.The high temperature properties of high titanium slags,which are strongly dependent of EAF smelting,energy consumption,are of great significance for the refinement operation.The conductivity of high titanium slags is related heavily to the open arc operation,thermal effectiveness and the heating distribution of the melt bath,and then influence the comprehensive energy consumption.The A·C impedance spectrum was used in this study to systematically measure the effects of composition and temperature on the electrical conductivity of high titanium slag systems.The results show that the increasing of FeO,CaO,SiO2 and MgO can lead to decrease of electrical conductivity,whereas the TiO2 and Ti2O3 exert opposite influence.It shows that,once completely melted,the electrical conductivity of these slags with TiO2 content 75% and above reach to 60~170 S/cm varying from specific composition and temperature.The XRD detection results of slags after cooling with the furnace show that the main phases of these slags are(Fe · Mg)xTiyO5 and TiO2.Molecular Dynamics Simulation results of TiO2-FeO-CaO-SiO2-MgO-Al2O3 show that the bond length of the atoms from short to long are Si-O < Al-O <Fe-O <Ti-O<Mg-O<Ca-O<O-O,respectively;the corresponding stability sequence of bonds is Si-O >Al-O >Fe-O >Ti-O> Mg-O> Ca-O> O-O.Meanwhile,the average coordination number of CNSi-O,CNAl-O,CNFe-O,CNTi-O,CNMg-O and CNCa-O are 4.00,4.52,4.30,5.46,4.92 and 6.34.The statistics result shows that the Ti-O coordination number is 5.46,indicating that Ti tend to form octahedral structure.Through the mean square displacement analysis,it can be found that,the sequence of atomic diffusion capacity of the titanium slag is Mg>Fe>O>Al>Ti>Si.[TiO6] polyhedron consists of main structure form between Ti and O in both titanium bearing BF slags and high titanium slags,where the coordination number of Ti-O in BF slag decrease with the increase of TiO2 and the increase with TiO2 content in high titanium slag.