Abstract:Crystalline aluminum chloride in alumina production process by fly ash hydrochloric acid method is calcined and converted into an alumina product, and calcination method has great influence on physical and chemical properties of alumina. Phase transformation of crystalline aluminum chloride at different calcination temperatures was studied, and two-step roasting at low temperature and high temperature and flue gas absorption tests were carried out. The results show that interior of alumina produced by two-step calcination has multi-layered sheet-like loose and porous structure with crystal form of γ-Al2O3, and α-Al2O3 is not formed. Particle size of product is bigger than that of alumina produced by one-step calcination, which is beneficial to alumina electrolysis. Recovery rate of hydrochloric acid is 95.79%, and absorption efficiency of hydrogen chloride in calcined flue gas is high.