Rheological Property And Melt Structure Of High Titania Slag

Titanium is a kind of strategic resources, and its reserves are abundant. The products containing titanium are widely applied in the field of national defense and economy. With the further development of titanium industry and nature rutile exhausting, the ilmenite which low grade but rich reserves is drew great attention in the titanium industry. However, the ilmenite only containing 42-48% titanium dioxide, therefore, it often is enriched for high titania slag to used in subsequent processing. The carbothermic reduction in electric furnace is the most common smelting technology. The key factor is the physical properties of slag phase to decide the separation efficiency between the slag and metal during the smelting processing. The higher melting point of high titanium slag is main reason to difficultly measure all kind of properties. The precise control of smelting processing is hindered and the development of production of titania slag limited due to lacking of basic data of titania slag. Especially the Panzhihua titania slag bearing high Ca and Mg, the basic data is almost blank. Therefore, study on the physicochemical properties of high titania slagfor the development of titanium industry has important significance.The viscosity of titania slag bearing high Ca and Mg was measured using the equipments which were advanced and self-made for the viscosity properties in this dissertation. The rheological property was revealed combine with the high temperature melt structure. The above studies can provide theoretical support for reducing the energy consume、saving cost and optimizing the smelting parameter during the smelting processing of high titania slag.The main conclusions:① The viscosity of binary and ternary were measured using experimental method. The viscosity value is constant for Ti O2-Fe O-Ca O ternary slag. The viscosity of Ti O2-Fe O is reduced with increasing the Fe O content and temperature. The viscosity value is about 80 mpa.s once binary slag completely molten. Fe O can obvious reduce the turning point temperature and the reduced temperature is 112℃.The viscosity does not changed with temperature once completely molten no matter binary or ternary slag system. The viscosity of titania slag rapid increases with decreasing the temperature when the temperature under the turning point temperature. The viscosity value of ternary slag is about 70-130 mpa.s after completely molten. Ca O and Mg O can reduce the turning point temperature and Si O2 and Ti2O3 has contrary trend. The main phase of titania slag is Fe Ti2O5 and Ti O2. Ca Ti O3 can be found in the Ti O2-Fe O-Ca O ternary slag. The phase theoretical calculated results are accordance with experimental results.② The viscosity of hexahydroxy and industry titania slag were studied. These slags once completely molten are characterized by a viscosity of only 70-140 mpa.s, which remains fairly constant even with further increases in temperature. The titania slag easily crystallize and melting region get narrower. The viscosity and turning point temperature of titania slag decreases with increasing the reduction degree. Fe O can help to improving the liquidity, and reducing the viscosity and turning point temperature of melt. The viscosity and turning point temperature of titania slag decreasing with reducing the Ti O2 content. The main phase are(Fe Mg)xTiyO5 and Ti O2 after measure of viscosity.③ With the Raman spectroscopy, the structure of molten titania slag has been studied. The crystal form of Ti O2 is rutile in the titania slag by XRD and Raman spectroscopy analyze. The crystal structure of rutile is consisted of Ti O2 octahedron. Titanium atom locates the lattice center and oxide atom in the octahedral edges. Si O2、Mg Oand Ca O has no obvious effect on the Raman characteristic peak of titania slag. Ca2+ and Mg2+ can enter into titanium oxide octahedron as grid destroyer and form Ca Ti O3 and Mg Ti2O5, which reduce the melting point of titania slag. Titania slag has four Raman active modes. The Raman peak of titania slag is no difference with rutile. The Raman spectrum of titnaia slag exhibited a sharp band at 610-630 cm-1, which is high frequen cyvibration model of Ti O6 octahedron.