废催化剂微波-超声波强化处理工艺中稀有金属的行为

Behaviors of rare metals in process of microwave-ultrasonic enhanced treatment of spent catalyst

针对国内某石化企业废石化催化剂处理过程中出现的产品纯度低、污染大等问题,提出了一种微波-超声波强化处理废催化剂的工艺采用物质流方法对工艺中稀有金属钒、钼元素的行为进行研究。结果表明:采用微波-超声波强化处理工艺,可制备高纯V_2O_5产品(纯度>99.9%)和普通V2O5产品(纯度>99%),钒的直收率为91.32%,未有效回收的钒主要分散在浸出渣、净化沉淀渣、萃钒余液和二段反萃液沉淀母液中,共占原料钒的7.58%。同时,可以制备合格的钼酸铵产品,钼的直收率为91.68%,未有效回收的钼主要分散在浸出渣、净化沉淀渣、负载钒有机相、萃钼余液和沉钼母液中,共占原料钼的7.99%。本工艺的特色主要体现在微波强化浸出和超声波强化反萃工序。微波强化浸出工艺中,钒和钼的浸出效率得到明显提高,这与反应的温度体系、矿物宏/微观结构变化以及高价钒含量的提高有密切关系。超声波反萃工艺可明显缩短反萃时间,超声波技术可降低晶体的团聚程度,有效消除氯化铵反萃过程中团聚晶体堵塞管道的现象。

Aiming at the problems of low product purity and high pollution in the treatment process of spent petrochemical catalyst for a petrochemical enterprise in China,a microwave-ultrasonic enhanced process for spent catalyst treatment was proposed,and the behaviors of vanadium and molybdenum in the process were studied by material flow method.The results show that high purity V2O5 product(purity>99.9%)and common V2O5 product(purity>99%)can be prepared by microwave-ultrasonic enhanced treatment process.The direct yield of vanadium is 91.32%.The ineffective recovery of vanadium is mainly dispersed in the leached residue,purified precipitation residue,vanadium extraction raffinate and second stage back-extraction solution precipitated solution,which account for 7.58%of vanadium in the raw material.At the same time,qualified ammonium molybdate product can be prepared.The direct yield of molybdenum is 91.68%.The ineffective recovery of molybdenum is mainly dispersed in the leached residue,purified precipitation residue,loaded vanadium organic phase,molybdenum extraction raffinate and molybdenum precipitated solution,which account for 7.99%of molybdenum in the raw material.The characteristics of this process are mainly reflected in microwave enhanced leaching and ultrasonic enhanced back-extraction process.In the microwave enhanced leaching process,the leaching efficiencies of vanadium and molybdenum are obviously improved,which is attributed to the temperature system of the reaction,the macro/microstructure change of the mineral and the increase of the high valence state vanadium content.Ultrasonic back-extraction technology can obviously shorten the back-extraction time.Moreover,ultrasound can reduce the agglomeration degree of crystals and effectively eliminate the phenomenon of the agglomeration crystals blocking the pipes in the ammonium chloride back-extraction process.