废脱硝催化剂钒、钨的浸出-搅拌对浸出率的影响

Leaching of V and W fromspent SCR catalyst-Effect of agitation on leaching rates

实现废脱硝催化剂高效综合再利用具有重大的社会和经济效益。本文采用NaOH浸出废脱硝催化剂中钒钨离子并考察其浸出影响因素,对比研究了搅拌和不搅拌作用下废脱硝催化剂中的钨离子浸出动力学。结果表明,提高浸出温度和NaOH浓度均有利于钒、钨的浸出;在搅拌条件下(350 r/min),液固比3.5∶1,浸出温度160℃,NaOH浓度40%,浸出时间3.5 h,钒、钨浸出率均达到100%。动力学研究结果钨离子浸出过程属于固膜扩散控制,搅拌条件下钨浸出表观活化能为29.28 kJ/mol,而不搅拌时,其表观活化能仅为1.26 kJ/mol,搅拌强化可增加扩散速率,减小扩散阻力,强化钒钨的浸出。

It is of great economic and social benefits for the recovery and reuse of valuable metals in waste SCR denitrification catalysts.In this paper,the vanadium and tungsten ions in waste denitrification catalyst were leached by NaOH and the factors affecting the leaching rates were investigated.Results showed that increasing the leaching temperature and NaOH concentration were beneficial to the leaching of vanadium and tungsten.The leaching rates of vanadium and tungsten could reach 100%under the condition of liquid-solid ratio of 3.5∶1,leaching temperature of 160℃,NaOH concentration of 40%,and the leaching time of 3.5 h.The process of tungsten ion leaching was controlled by solid membrane diffusion.Under agitation condition(350 r/min),the apparent activation energy of tungsten leaching was 29.28 kJ/mol,while without agitation,the apparent activation energy was only 1.26 kJ/mol.Agitation could increase the diffusion rate,reduce the diffusion resistance,and enhance the leaching rates vanadium and tungsten.