Abstract:Influence of caustic alkali concentration, reaction temperature and reaction time on precipitation of vanadate in aluminum hydroxide washing solution was studied applying washing liquid of aluminum hydroxide during alumina production as raw material. The results show that precipitation rate of vanadate rises with increase of caustic concentration and reaction time, but drops with increase of reaction temperature. When reaction temperature is 30 ℃, concentration of caustic soda in sodium aluminate solution is 200 g/L, and reaction time is 72 h, vanadium content in solution can be reduced by more than 60%. XRD and SEM analysis shows that vanadate precipitated in form of sodium vanadate and sodium metavanadate, and its crystal structure is octahedron.