Investigation of alumina preparation from aluminum chloride aqueous solution by electrical transformation

Abstract

High-alumina fly ash is an alumina-rich mineral resource that can potentially replace low-grade bauxite. While a wide range of different traditional processes are available for extracting alumina from high-alumina fly ash, these processes have many disadvantages. Northeastern University has recently proposed a new electrotransformation processing technique for transforming AlCl3 into Al2O3 in the process of extracting Al2O3 from high-alumina fly ash by the hydrochloric acid method. The feasibility of this new electrotransformation method was studied in this paper. The effects of the current intensity, electrotransformation time, initial electrotransformation temperature and initial HCl concentration on the electrotransformation process and roasting products were investigated. The results show that the pH of the electrolyte increases with increasing current strength, electrolytic time, initial electrotransformation temperature and HCl initial concentration, and its value tends to be 3.2. Under these conditions, XRD and SEM examinations confirm that the roasting products are Al2O3 sheets with a cubic crystal system. An examination of the grain size shows that the grain sizes are uniform. Elemental content examinations show that the Cl contents of the obtained products are <0.08%. These results confirm that the new electrotransformation method is feasible for industrial use.