Element Distribution And Production Process During Titanium Slag Smelting In Circular Closed Direct Current Arc Furnace

The technology of titanium slag smelting in large-scale circular closed direct current arc furnace has an advantage of low energy consumption, little environmental pollution, resource use efficiency. According to the characteristics of titanium ore in Yunnan, which contain high metal impurities, such as Ca, Mg, Si, Al. The element distribution and affecting factors in producting of titanium slag smelting in large-scale circular closed direct current arc furnace was studied, which can help optimize the industrial production. It’s the first time that use the large-scale direct current arc furnace for high titanium slag production in China, the work can enrich the theoretical research. In this work, the effects of AIR (the ratio of anthracite to ilmenite), ilmenite and reducing angent component, process conditions on the element distribution in slag, pig iron, the exhaust gas and dust were analyzed, based on experimental studies, chemical equilibrium calculation method in multi-phase, multi-component system. The research provided theoretical basis of ilmenite smelting process in DC arc furnace and helps for high grade titanium slag production in Yunnan, and the results are verified by experiments.Through research, we can see the AIR have an important influence on the behavior of elements distribution in high titanium slag and iron. With AIR increased, TiO2, MgO, CaO, Al2O3, SiO2 mass fraction in the high titanium slag showed an increasing trend, while the FeO content decreased, adjust AIR to achieve selective reduction of oxide.The ilmenite component (TiO2, Fe2O3, FeO) has a great effect on element distribution in slag. With TiO2 and FeO anmount increased in ilmenite, the amount of C used for TiO2 and FeO reduction increased, the total mass fraction of TiO2 and Ti2O3 in slag increased, the mass fraction of FeO in slag decreased, the amount of C used for Fe2O3 reduction decreased. Reductant C is mainly used for reducting FeO and TiO2 in ilmenite. However, with the Fe2O3 amount in ilmenlite increased, the trend of composition in slag was opposited. The sensitivity of other components on the total TiO2 in slag was displayed as:SiO2> MgO> Al2O3> CaO. while the sensitivity of other components on the Ti2O3 in slag is displayed as: MgO>Al2O3>SiO2>CaO.During titanium slag smelting process by closed DC arc furnace, the heating conditions of ilmenite and power input situations were determined by the arc length. Energy input to the furnace has a great effect on the IPR (Ratio of ilmenite mass to power), the productivity of the slag and iron. With power input and the current intensity increased, the arc length and the resistance increased. The control of these parameters can help to adjust the length of the arc as input power, current strength, resistance, electrode position, to control the heat balance and energy input finally. With the input power increased, IPR values shows an increasing trend, moreover, the feedrate of anthracite and ilmenite increased, thus increased the yield of slag and iron.The thickness of freeze lining determined the process stability of titanium slag smelting in DC arc furnace. The process temperature of the furnace and the MgO content have a significant effect on the thickness of freeze lining in DC arc furnace. The experiment processing temperature controlled in the range of 1700℃-1750℃, and MgO content in slag controlled less than 1.8%, can effectively avoid the accident of DC furnace burnthrough. With processing temperature increased, MgO content in slag increases, and the thickness of freeze lining decreased.