METHOD FOR PRODUCING CATALYST-GRADE ALUMINA FROM ALUMINUM SULPHATE

摘要

A method of making activated alumina includes beginning with a leach liquor of potassium and aluminum sulphates that is subjected to a surface-cooled crystallizer with a heat-exchanger input temperature of 160.degree.F and a surface-chilled temperature of 60.degree.F to 80.degree.F. Crystals of aluminum sulphate are precipitated and recrystalized by evaporation in a vacuum and at an elevated temperature. Purified crystals of aluminum sulphate are then dried at 50.degree.-60.degree.C. The dried aluminum sulphate crystals are then dehydrated at 400.degree.-450.degree.C after a rise rate of 10.degree.-20.degree.C per minute to drive off most of the water. A roasting and recalcination step at 900.degree.C-950.degree.C after a rise rate of 10.degree.-20.degree.C per minute is used drive off the sulphate. The remaining alumina is useful as a high-grade catalyst.