Intensifying recovery of metallic aluminum in secondary aluminum dross by alkali roasting-water leaching

An innovative process was proposed to recover metallic aluminum from secondary aluminum dross (SAD) by alkali roasting-water leaching. Thermodynamic calculations and experimental results were used to illustrate the phase transformation and reaction mechanism of the alkali roasting process. The leaching behaviors of roasted residue were also analyzed. Under optimal conditions, the aluminum extraction rate reached 93.08%. In addition, the kinetics of the water leaching of roasted products was studied through shrinking core model, and it was revealed that the leaching process of aluminum was in accord with diffusion control. The apparent activation energy of the leaching process was calculated to be 3.44 kJ/mol. Based on the above study, the underlying mechanism of the alkali roasting-water leaching was clarified.