Study On The Transformation Behavior Of Vanadium, Molybdenum And Aluminum In The Process Of Sodium Catalyst Roasting And Immersion

HDS catalyst is supported by alumina, molybdenum and other metals are the active ngredients. After prolonged thermal and chemical action and active ingredients loss effectiveness, the catalyst becomes the spent catalyst. Containing vanadium, molybdenum und alumina, the spent catalyst is an important secondary resource. It will reduce the loss of valuable metals and avoid environment pollution by comprehensive recovering of the spent catalyst. It has the important sense of economy and environment.XRF analysis, multi-element analysis, XRD analysis, SEM analysis and differential thermal analysis were used for analyzing the property of the spent catalyst. Based on the property of the spent catalyst and extensive literature, soda roasting-water leaching was adopted to extract vanadium, molybdenum and alumina from the spent catalyst.The conversion behavior of vanadium, molybdenum and alumina was researched in the roasting process. Thermodynamic was calculated in the roasting process. Roasted products of different roasting temperatures were analyzed by XRD and SEM. The results show that the reaction of alumina and sodium carbonate required high roasting temperature. At roasted condition of low temperature, reacted with sodium carbonate, the oxide of vanadium and molybdenum converted into the corresponding sodium salt, aluminum did not react with sodium ccarbonate; at roasted condition of high temperature, reacted with sodium carbonate, the oxide of vanadium, molybdenum and alumina all converted into the corresponding sodium salt. It can be achieved that extract vanadium, molybdenum and alumina selectively by controlling the roasting temperature.The kinetic test conditions were researched about extracting vanadium, molybdenum and alumina from the spent catalyst by soda roasting-water leaching. At the condition of roasting temperature1000℃, roasting time30min, the dosage of Na2CO384%, leaching temperature80℃, leaching time30min, stirring intensity400rpm and liquid-solid ratio6:1, the leaching rate of vanadium, molybdenum and alumina is97%,99%and95%respectively, the leaching result is satisfactory.