Study On Recovery Of Alumina From Waste Hydrodesulfurization Catalyst

The waste hydrodesulfurization catalyst is a deactivation catalyst that uses alumina as a carrier and contains a large amount of heavy metals such as vanadium,molybdenum,nickel,and iron.Comprehensive recovery of spent hydrodesulfurization catalysts not only prevents the loss and waste of heavy metals,but also reduces pollution to the environment,and has great economic and environmental significance.In this paper,a waste hydrodesulfurization catalyst is taken as the research object,the extraction and separation of aluminum and other metals in the waste catalyst and the preparation of microporous alumina are carried out,and the preparation of microporous alumina from waste hydrodesulfurization catalyst is proposed new technology.The main research contents and innovations of the paper are as follows:1.Separation of aluminum from nickel and iron in waste hydrodesulfurization catalystUnder the roasting-leaching conditions of sodium carbonate and alumina of spent hydrodesulfurization catalyst at a molar ratio of 2.5,roasting temperature of 600?,roasting time of 4 h,leaching temperature of 80?,leaching time of 30 min,liquid-solid ratio of 3:1,and stirring speed of 500 rpm,the leaching amount of aluminum,vanadium and molybdenum of the spent catalyst reached the highest,while nickel iron was completely enriched in the leaching slag.2.Separation of aluminum from vanadium and molybdenum in alkaline mediaIn an alkaline medium in which aluminum,vanadium,and molybdenum coexist,by distributed precipitation,barium hydroxide reacts with VO43-at 40? to separate vanadium from aluminum and molybdenum;subsequently,barium aluminate react with MoO42-at 80? to separate aluminum and molybdenum.The separation result of aluminum from vanadium and molybdenum is good,and the sodium aluminate solution is deeply purified.3.Preparation of microporous aluminaAfter waste hydrodesulfurization catalyst with sodium carbonate roasting-leaching and sodium aluminate solution refining,a deeply purified sodium aluminate solution is obtained,which provides favorable conditions for the preparation of microporous alumina.Based on the preliminary work of the research group,the aluminum sulfate solution and sodium aluminate solution were used as raw materials to investigate the effect of aluminum sulfate concentration on the preparation of alumina,and microporous alumina was prepared.This paper proposes a comprehensive utilization process for preparing macroporous alumina from spent hydrodesulfurization catalyst.This process can achieve the effective utilization of waste hydrodesulfurization catalyst,and obtain three products of alumina,barium vanadate and barium molybdate.The prepared alumina has a specific surface area of 594.8 m2/g and a pore volume of 2.59 cm3/g.