TiO_2碳热还原与高炉钛渣提取碳氮化钛分析

Analysis of carbothermal reduction of TiO_2 and extraction of titanium carbonitride from the blast furnace slag bearing titania

总结TiO2的碳热还原法制取碳(氮)化钛的研究成果,并对高炉钛渣中钙钛矿的碳热还原进行了热力学分析。研究结果表明,TiO2的碳热还原可分为三个阶段:TiO2→TinO2n-1,该阶段还原较快;TinO2n-1→TiCxNzOy,该阶段碳的气化反应起中心作用;TiCxNzOy→Ti(C,N)是一个较慢的扩散过程。TiO2的碳热还原氮化反应中难以出现TiO相;N2气的引入,可降低还原温度。通过调整高炉钛渣组成(包括碱度),使之生成CaO.Al2O3.2SiO2,更有利于碳(氮)化钛的生成。

The research efforts in preparation of titanium carbonitride by carbothermal reduction of TiO2 are summarized. The thermodynamic analysis of carbothermal reduction of perovskite phase in the blast furnace slag bearing titania is carried out. It is found that the carbothermal reduction of TiO2 falls into three stages： TiO2→TinO2n-1 is the 1st stage during which reduction is fast; TinO2n-1→TiCxNzOy is the 2nd during which the Boudouard＇s reaction plays a central role; and TiCxNzOy→Ti （C,N）is the 3rd during which the diffuse process is slow. TiO phase is hardly found in carbothermal reduction of TiO2, and the reduction temperature can be reduced by introducing N2 into the reaction. Besides, CaO Al2O3·2SiO2 may be formed in the slag by adjusting the components of slag, which also accelerates the formation of titanium carbonitride.