Extraction method and apparatus of high pure alumina from fly ash using microwave

摘要

A method for extracting high pure alumina from fly ash using heating source of microwave is provided to improve extraction rates from 18.3-20.6% to 25-72% in comparison with an existing acid-base method. A method for extracting high pure alumina from fly ash comprises the following steps of: performing sulfatation by adding ammonium sulfate to fly ash and extracting alumina from the sulfatation-product using sulfuric acid within a unit generating microwave heating source; filtering alumina extract to separate residue and alumina leachate and washing the residue; collecting ammonium alum in a crystal shape from the alumina extract; and removing impurity from the ammonium alum crystalline through re-crystallization.