FeTiO3-Fe2O3固溶体合成及其碳热还原研究

Synthesis and non-isothermal carbothermic reduction of FeTiO3-Fe2O3 solid solution systems

摘要:

为明确Fe₂O₃固溶对FeTiO₃还原过程的影响机理,本文基于粉末煅烧法合成(1-x)FeTiO₃?xFe₂O₃固溶体(0≤x≤1),研究了非等温碳热还原条件下固溶体的还原行为,并采用X射线衍射仪(XRD)和扫描电镜-能谱仪(SEM-EDS)对合成固溶体及还原产物进行表征。结果表明,实验合成固溶体质地均匀,纯度较高,且x越大,FeTiO₃晶格畸变程度越大。固溶体开始还原温度和还原速率(还原度α的增大速率)均随着x值的增加而增加。固溶Fe₂O₃能够促进FeTiO₃还原,且在还原过程中存在过渡相Fe₂TiO₄和Fe₃Ti₃O₁₀。固溶体-石墨交界面首先形成浮士体(FeO)、钛铁尖晶石(Fe₂TiO₄)和TiO₂,进一步还原生成金属Fe和Ti₂O₃。非等温碳热还原过程动力学计算分析,得出表观活化能为295.54 kJ/mol。

Abstract:

To exam the carbothermic reduction behaviors of the (1-x)FeTiO₃?xFe₂O₃ solid solutions with various x value, the solid solutions were artificially synthesized successfully and then subjected to non-isothermal carbothermic reduction. The results show that the solid solutions synthesized in laboratory were uniform texture and high purity. Meanwhile, lattice distortion degree of FeTiO₃ was greater with increasing the value of x, and the initial reduction temperature and reduction rate which is the increasing rate of reduction degree α were also improved. The reduction could be improved for FeTiO₃ as Fe₂O₃ dissolving, and the Fe₂TiO₄ as well as Fe₃Ti₃O₁₀ were existed as the transition phase in the reduction process. FeO, Fe₂TiO₄ and TiO₂ were firstly generated in the interface of solid - graphite, and then reduced to Fe and Ti₂O₃. It is concluded that the apparent activation energy of 295.54 kJ/mol from the calculation and analysis of the non-isothermal kinetics for the carbon thermal reduction process.