Study On The Influence Law Of Titanium-containing Blast Furnace Slag Composition On TiC Formation Behavior

Vanadium-titanium magnetite is abundant in panxi area.At present,it is mainly used by blast furnace smelting.The content of Ti O₂ in the ore is as high as 10wt.%.In the process of blast furnace smelting,Ti O₂ was over-reduced into solid phase particles with high melting point.Therefore,ordinary ore should be added during smelting to avoid a series of problems.Such as slag viscosity,slag foaming and iron in slag.However,with the ordinary ore not only unfavorable to the recycling of vanadium ore,also can increase the smelting cost.From the perspective of the comprehensive utilization of resources.and the long-term development of enterprises,adding ordinary ore is not a long-term solution.Therefore,further reducing the ordinary ore rate,and even realizing the smelting of all-vanadium-titanium magnetite,is of great significance for the effective use of resources.At present,when the ratio of ordinary ore is reduced,the content of Ti O₂ in slag increases accordingly,resulting in problems such as slag viscosity and foam slag.Therefore,in order to increase the comprehensive utilization efficiency of vanadium titanium magnetite,it is necessary to solve the phenomenon of over reduction of Ti O₂.Combined with previous studies,this paper analyzed the reduction mechanism of pure Ti O₂ by means of thermograin-mass spectrometry.By adjusting different components in titanium-bearing blast furnace slag,the influence of each component on the phenomenon of Ti O₂ overreduction in titanium-bearing blast furnace slag was studied.The main conclusions are as follows:The thermodynamic calculation show that.the final products of carbon thermal reduction of Ti O₂ in different forms were all Ti C_xO_y.The proportion of Ti C in Ti C_xO_yvaries with the carbon allocation.When the reaction temperature is 1500?,Ti C_xO_y can be generated.The reduction path of Ti O₂ in different forms is also different.When pure material is reduced,the intermediate product has no Ti₂O₃;when Ca Ti O₃ is reduced,the intermediate product is Ca₂Ti₂O₅;when slag is reduced,the intermediate product is Perovskite.By adjusting the particle size and heating rate of the raw material,the experimental method and conditions for the gradual reduction of titanium-bearing slag and Ti O₂ pure materials were obtained.Carbon reduction was carried out on pure Ti O₂,and the reduction path was obtained:Ti O₂?Ti₃O₅?Ti₂O₃?Ti C.According to the Srink equation,the activation energies of the first two stages were 376 k J/mol and 651 k J/mol,respectively.The carbon reduction experiment of Ca Ti O₃ showed that the initial reaction temperature of perovskite was 1037?.Compared with Ti O₂,the initial reaction rate was slow,until the temperature rose to 1264?,and the reaction was significantly accelerated.Compared with pure Ti O₂,Ca Ti O₃ carbothermal reduction takes less time to reach the end point.For high titanium type blast furnace slag containing titanium,Ti₂O₃ was not found in the grade-by-step reduction products of Ti O₂,and the reduction path was:Ti O₂?Ti₃O₅?Ti C_xO_y?Ti C.At the initial stage of the reaction,the increase of Ti O₂content would lead to the increase of its activity and the reduction rate.After the reaction entered the third stage,the reaction rate increased with less Ti O₂n slag.The increase of Mg O content will also promote the reduction of Ti O₂.In the first and second stages,the more Mg O in slag,the greater the reduction rate.After the reaction enters the third stage,the effect of Mg O on the reaction rate is weakened.In contrast to Mg O,Ca O inhibited the reduction of Ti O₂ in slag in the early stage of reaction and promoted the carbonization of titanium carbon oxides into Ti C in the late stage of reaction.