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TiC0.5O1.5;第一阶段动力学方程为α2=kt,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（1-α）1-1=kt,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2[（1-α）1/2-1]=kt,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53.93kJ/mol,第四阶段动力学方程为1-2α/3-（1-α）2/3=kt,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.
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 Tin O2n-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 α2 =kt,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 （1-α）-1-1 =kt,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 2[（1-α）-1/2-1] =kt,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 1-2α/3-（1-α）2/3 =kt,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.
出处
《有色金属（冶炼部分）》
CAS
北大核心
2014年第3期46-50,共5页
Nonferrous Metals（Extractive Metallurgy)
基金
国家重点基础研究发展计划(973计划)项目(2013CB632606)
关键词
碳氧钛
动力学
还原历程
表观活化能
titanium oxycarbide
dynamics
reduction process
apparent activation energy
