摘要
采用扫描电镜(SEM)观察了低钒钒渣(V2O3 8%)不同结晶温度及不同冷却时间的结晶形貌,用X射线衍射物相分析(XRD)及能谱分析仪(EDS)研究了钒渣中V,Fe,Si等各主要元素的赋存形式,用IPP软件统计分析了不同条件下钒渣物相组成和尖晶石生长规律及其影响因素,并用JMAK模型描述了等温过程尖晶石长大动力学行为,得到了尖晶石生长表观活化能。结果表明:钒渣主要由尖晶石相和硅酸盐相组成,硅酸盐相包括大量的橄榄石相及微量的辉石相;钒主要赋存于MgV2O4,FexV3-xO4,MnxV3-xO4(1≤x≤3)等尖晶石相中,钒基本不进入硅酸盐相;尖晶石长大主要包括晶核长大与Ostwald粗化两个过程;温度1523 K左右有利于尖晶石生长,过高则过冷度较小,过低则原子扩散缓慢,均不利用尖晶石生长;1523 K保温5 min,尖晶石平均粒径仅为9.83μm,随着保温时间的延长,尖晶石尺寸逐渐增大,30min时尖晶石平均粒径为26.8μm,30 min后,尖晶石生长缓慢;尖晶石生长速率可用转变分数表示,随时间延长,转变分数逐渐降低;尖晶石生长过程可用JMAK方程描述,其表观活化能为575 kJ.mol-1。
Based on the study of the mineral phase of vanadium slag,the growth regularity of the spinels and their influencing factors were analyzed.The isothermal growth kinetics of the spinels was described by JMAK equation.The results showed that spinels and silicates were the major phases in the vanadium slag samples,and V was enriched in the spinel phases.The temperature around 1523 K benefited the growth of the spinel phases.The mean diameter of the spinels was 9.83 μm when the holding time was 5 min,and increased with the prolongation of holding time.When being held for 30 min,the mean diameter reached 26.8 μm.The growth rate slowed down after 30 min.The growth process of spinel phases could be described by JMAK equation.The apparent activation energy was 575 kJ·mol-1.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2011年第2期281-285,共5页
Chinese Journal of Rare Metals
基金
国家973计划(2007CB613503)资助项目
国家863计划(2008AA031104)资助项目
