Discussion of Alumina Acid Production from Fly Ash of Power Plants

Coal fly ash from power plants contains large amounts of alumina. When it is used to produce alumina, it can not only overcome the shortage of alumina resources, but also avoid environmental contamination. The methods and the status quo of the research on alumna production from fly ash are reviewed and the characteristics, trends and feasibility of these methods are analyzed. Some recommendations are given for improving the product quality, reducing the investment and lowering the cost of the alumina production. One method of acid extracting alumina from fly ash(GP method) is introduced, which consists of three steps of leaching with sulfuric acid, removing impurities with hydrochloric acid and ammonia conversion. With this method, the reaction temperature, the energy consumption and the production cost are low and there are not new solid emissions generated from the closed cycle process. The issues on the alumina crystal size, acid-resistant materials as well as iron and other impurities removal need to be further studied.