微波场下的钒渣氯化动力学  

Kinetics of chlorination of vanadium slag by microwave heating

作　　者：谭博 王丽君 闫柏军[3] 周国治 TAN Bo;WANG Li-jun;YAN Bai-jun;CHOU Kuo-chih(Collaborative Innovation Center of Steel Technology,University of Science and Technology Beijing,Beijing 100083,China;State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,Beijing 100083,China;School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学钢铁共性技术协同创新中心,北京100083 [2]北京科技大学钢铁冶金新技术国家重点实验室,北京100083 [3]北京科技大学冶金与生态工程学院,北京100083

出　　处：《工程科学学报》2020年第9期1157-1164,共8页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(51774027,51734002)。

摘　　要：研究了微波加热条件下(500~800℃),AlCl3氯化钒渣中有价金属Fe、Mn、V和Cr变温动力学.通过X射线衍射和扫描电镜能谱表征了氯化产物随时间的物相演变和形貌变化,考察了AlCl3/钒渣的质量比和熔盐配比对氯化提取率的影响.结果表明,AlCl3/钒渣的质量比为1.5、(NaCl-KCl)/AlCl3熔盐质量比为1.66∶1时Fe、Mn、V和Cr的提取率最佳,分别为91.66%、92.96%、82.67%、75.82%和63.14%,微波加热30 min,5种元素的提取率达到或者超过常规加热方式6 h的氯化提取效果.通过热力学和动力学分析,橄榄石相优先于尖晶石相发生氯化反应.而且V和Cr的氯化反应速度小于Fe和Mn.Fe和Mn氯化过程为扩散控制,其非等温扩散活化能为17.02和17.10 kJ·mol-1, V和Cr在氯化过程中的限制性环节为界面化学反应,其表观活化能分别为40.00和50.92 kJ·mol-1;微波与熔盐耦合强化氯化反应的机理可以描述为扩散作用增强和局部化学反应增强.Microwave heating was used in this study to chlorinate the extraction of Fe, Mn, V, and Cr from vanadium slag using AlCl3 molten salt at a temperature range from 500 to 800 ℃. Microwave heating chlorination kinetics was studied in a non-isothermal mode. The effects of the AlCl3/vanadium slag mass ratio and molten salt ratio on the extraction rate of chlorination peoducts were investigated. The structure and morphology evolution of microwave heating chlorination products were characterized by X-ray diffraction and scanning electron microscope with energy dispersive spectrometer. The results show that the highest extraction rate of the five elements(Fe, Mn, V, Cr, and Ti) can be achieved as 91.66%, 92.96%, 82.67%, 75.82% and 63.14%, when the mass ratios of AlCl3/vanadium slag and NaCl–KCl/AlCl3 are 1.5 and 1.66, respectively. These extraction rates in the microwave heating mode for 30 min are reached and exceeded by 6 h in the conventional heating method. Microwave heating will minimize the chlorination time and reduce the volatilization of AlCl3. Based on the thermodynamics and kinetic analysis, the different phases of vanadium slag can be chlorinated using AlCl3 in the range from 400 to 800 ℃, and the olivine phase is superior to the spinel phase in chlorination. In addition,the chlorination rates of V and Cr are slower than those of Fe and Mn, and increasing the reaction time is advantageous for the chlorination of V and Cr. The chlorination of Fe and Mn is controlled by diffusion, and the non-isothermal diffusion activation energies of Fe and Mn are 17.02 and 17.10 kJ·mol-1, respectively. In contrast, the chlorination of V and Cr is limited in the interfacial chemical reaction step, for whom the activation energies give 40.00 and 50.92 kJ·mol-1, respectively. The combination effect of the microwave and molten salt on the chlorinating vanadium slag can be attributed to the enhancement of the diffusion and local chemical reaction.

关 键 词：钒渣 微波加热 熔盐 变温动力学 强化扩散 

分 类 号：TF19[冶金工程—冶金物理化学]