Direct Leaching of Alumina From Fly Ash Using Sulfuric Acid

Direct leaching of Al2O3from circulating fluid bed fly ash using sulfuric acid was researched.The effect of leaching temperature,time and sulfuric acid concentration on leaching rate of Al2O3were examined.The experimental results show that the leaching temperature and time influence markedly the leaching rate of Al2O3,and effect of sulfuric concentration is not obvious.When temperature is 180 ℃,leaching time is 5h,the ratio between liquid volumetric and solid mass is 5∶1and sulfuric acid initial concentration is 3.7mol/L,the leaching rate of Al2O3and Fe2O3can reach 94.16%and 95.1%,leaching rate of other impurities are lower.