Secondary aluminum dross is generated from the aluminum remelting process and is considered as hazardous waste due to the presence of soluble salts and various active compounds. This chapter presents eco-friendly and economical processes for the treatment of secondary aluminum dross. In water leaching process, the greenhouse gas CO2 was introduced to inhibit the hydrolysis of AlN and reduce emissions of the pollutant gas NH3. The chlorides (NaCl, KCl) were successfully removed, and the solid residue was utilized for Sialon material preparation. In an alternative leaching process, the temperature of leachate was raised to maximize AlN hydrolysis and minimize NH3 solubility. The evolved ammonia was captured by CO2-saturated water. The residue after leaching was treated with molten NaOH at high temperature to extract alumina.