The aluminum smelting process produces a large number of by-products, known as slags that can be reused for landfill or dumped into landfills. Smelting waste contains aluminum in the form of alumina at high concentration (around 30%). Direct disposal of this waste into the environment can cause environmental pollution. Aluminum in the waste can react with water and produce corrosion products. Therefore, this study explores the potential for recovering aluminum from smelting waste using an acid leaching process. The efficiency evaluation of aluminum recovery was carried out by optimizing using Response Surface Methodology (RSM) with Box-Behnken Design. Optimization results show that aluminum recovery increases with increasing temperature and heating time. The acid concentration and the ratio of solid to liquid showed an initial increase followed by a reduction in recovery with an increase in concentration and a solid- liquid ratio. RSM predicts that aluminum recovery can reach optimum when heated at 50 °C for 6 hours and 1.5 ratio of solid/liquid using 2 M acid concentration.