DOC《真空碳热还原制备碳氧钛的动力学研究》

真空碳热还原制备碳氧钛的动力学研究 朱福兴1,邓斌1,秦庆东2,王芳平2 (1.

攀钢集团研究院有限公司 钒钛资源综合利用国家重点实验室,四川攀枝花 617000;

2.中国铝业股份有限公司 郑州研究院,郑州 450041) 摘要:采用非等温固相模型对碳热还原TiO2历程和动力学条件进行研究.结果表明,真空碳热还原TiO2可分为四个阶段,第一阶段(1 373~1

523 K)主要物相为C和TinO2n-1(n≥5),第二阶段(1 523~1

673 K)主要物相为C、TiC0.5O0.5和TinO2n-1(2≤n≤4),第三阶段(1 673~1

833 K)主要物相为C、Ti2O3和TiC0.5O0.5,第四阶段(1 833~1

973 K)主要物相为TiC0.5O0.5;

第一阶段动力学方程为,受一维扩散控制,表观活化能为113.55 kJ/mol,第二阶段动力学方程为,受二级化学反应控制,温度对还原率影响较大,表观活化能为303.36 kJ/mol,第三阶段动力学方程为,受1.5级化学反应控制,还原剂不足对反应影响较大,表观活化能为53.93 kJ/mol,第四阶段动力学方程为,受三维扩散控制,物料疏松成为晶核长大的限制环节,表观活化能为99.22 kJ/mol. 关键词:碳氧钛;

动力学;

还原历程;

表观活化能 中图分类号:TF823 文献标志码:A 文章编号:1007-7545(2014)03-0000-00 Kinetic Study on Preparation of Titanium Oxycarbide by Vacuum Thermal Reduction ZHU Fu-xing1, DENG Bin1, QIN Qing-dong2, WANG Fang-ping2 (1. Pangang Group Research Institute Co., Ltd., State Key Laboratory of Vanadium and Titanium Comprehensive Resources Comprehensive Utilization, Panzhihua 617000, China, China;

2. Zhengzhou Research Institute of CHALCO, Zhengzhou 450041, China) Abstract: The process and dynamic condition of TiO2 carbothermic reduction were studied by non-isothermal solid model. The results show that carbothermic reduction process is divided into four stages. C and TinO2n-1(n≥5)are the main phases of the first stage (1 373~1

523 K), which gradually change into C, TiC0.5O0.5 and TinO2n-1(2≤n≤4)at the second stage (1 523~1

673 K). C, Ti2O3 and TiC0.5O0.5 are the main phases of the third stage(1 673~1

833 K), which finally change into TiC0.5O0.5 at the fourth stage (1 833~1

973 K). The kinetic equation of the first stage presents as , which is controlled by one-dimension diffusion with apparent activation energies of 113.55 kJ/mol. The kinetic equation of the second stage presents as , which is controlled by the second-order reaction with apparent activation energies of 303.36 kJ/mol. Temperature exerts significant influence in this stage. The kinetic equation of the third stage presents as , which is controlled by 1.5-order reaction with apparent activation energies of 53.93 kJ/mol, and this stage is limited by inadequate reducing agent. The kinetic equation of the last presents as , which is controlled by three-dimension diffusion with apparent activation energies of 99.22 kJ/mol, and this stage is mainly restricted by the loosing structure of product. Key words: titanium oxycarbide;

dynamics;

reduction process;

apparent activation energy 碳氧钛最先是在碳热还原TiO2过程中被发现的,因具有高熔点、高硬度、良好的导热性、导电性和抗腐蚀能力等优异性能,成为装潢、切割、电极等行业的新型材料[1-4].目前,制备碳氧钛的方法主要有固―固热还原法、气―固反应法、电化学脱氧法等,其中固―固反应法具有操作简单,反应效率高、生产周期短等优点而被广泛应用[5-7]. 固―固反应法制备碳氧钛可采用碳质还原剂和TiO