Improvements by the New Alusuisse Process for Producing Coarse Aluminum Hydrate in the Bayer Process

Abstract

The liquor productivity in the American Bayer process with a maximum of about 55 grams Al₂O₃ per litre compares very unfavourably with that obtained in the European process of up to 80 grams Al₂O₃ per litre. By the new Alusuisse process a liquor productivity can be obtained nearing that of the European process, while obtaining a strong aluminum hydroxide of coarse particle size of about 5 % less than 45/μm. The process has been used for the conversion from floury to sandy of the Gove Alumina Plant with a nominal capacity of 1.0 million tons per year. The modified plant has been running since November 1979 at the increased nominal capacity of 1.1 million tons per year producing an aluminum hydrate of about 5 % less than 45/μm.