摘要
采用聚乙烯吡咯烷酮(PVP)优化核壳型钒碳包裹前驱体结构,热处理前驱体获得满足国标VN16牌号的氮化钒(VN)。PVP的引入促进了碳粉在富钒溶液中的均匀分散,有利于多聚钒酸铵(APV)离子的氢键化,使其吸附于碳粉表面成核和生长,制备的前驱体有包覆完整稳定且厚度均匀适中的APV外壳、碳粉内核及小且均匀的粒径分布。在还原氮化过程中,前驱体到VN的相变过程为:APV→V_(2)O_(5)→V_(6)O_(13)→V_(7)O_(13)→VO_(2)→V_(3)O_(5)→V_(2)O_(3)→(VC)→VN。优化后的前驱体因其细密的核壳包覆结构和均匀的粒度分布,形成了更稳定的相反应界面和更多的反应活性位点,降低了各阶段的反应活化能(Ea),使还原氮化效率更高,更易向低价VO_(x)和VN转变。与现行碳热还原工艺相比,反应时间缩短75%,N_(2)流量由300 mL/min降低至200 mL/min,耗量约降低40%,显著降低生产成本。
In this study,polyvinyl pyrrolidone(PVP)is used to optimize the core-shell V@C precursor structure,and the precursor is heat-treated to obtain vanadium nitride(VN)up to the National Standard VN16 grade of China.The addition of PVP promotes both the uniform dispersion of the carbon powders in the vanadium rich solution and facilitates the hydrogen bonding of ammonium polyvanadate(APV)ions,which are adsorbed on the surface of carbon powders for nucleation and growth.The as-prepared precursor by adding PVP has better encapsulated and stable carbon powder core and APV shell with uniform and moderate thickness,as well as small and homogeneous particle size distribution.In the nitridation and reduction process,the phase transition from precursor to VN is as follows:APV→V_(2)O_(5)→V_(6)O_(13)→V_(7)O_(13)→VO_(2)→V_(3)O_(5)→V_(2)O_(3)→(VC)→VN.Due to its more stable core-shell coating structure and more uniform particle size distribution,the optimized precursor forms a more stable phase reaction interface and more active reaction sites,which reduces the reaction activation energy(Ea)at each stage,and makes it more efficient in reducing and nitriding and easier to transition to low-valent VO_(x)and VN.In comparison with current carbothermal reduction process,the reaction time is shortened by 75%,and the flow rate of N_(2)is reduced from 300 mL/min to 200 mL/min,the usage of N_(2)is reduced by 40%,significantly reducing production costs.
作者
薄文彬
张一敏
薛楠楠
刘红
Bo Wenbin;Zhang Yimin;Xue Nannan;Liu Hong(School of Resource and Environmental Engineering,Wuhan University of Science and Technology,State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control,Collaborative Innovation Center of Strategic Vanadium Resources Utilization,Hubei Provincial Engineering Technology Research Center of High Efficient Cleaning Utilization for Shale Vanadium Resource,Wuhan 430081,Hubei,China)
出处
《钢铁钒钛》
CAS
北大核心
2024年第5期1-8,共8页
Iron Steel Vanadium Titanium
基金
湖北省科技创新人才及服务专项战略科学家培养计划(2022EJD002)。
关键词
VN
PVP
核壳型前驱体
相反应界面
vanadium nitride
PVP
core-shell precursor
phase reaction interface
