Efficient recovery of aluminum from saline slag wastes

This work presents the procedure to improve the aluminum extracted from a hazardous waste from the recycling of aluminum, aluminum that could be used in the production of value-added materials, as well as with the generation of non-hazardous waste. The aluminum waste was treated under reflux and stirring with NaOH aqueous solutions taking into account two concentrations (1 and 2 mol/dm3), various times of extraction (1, 2 and 4 h) and 4th consecutive steps of extraction in order to obtain solutions with Al3+. The activation of the waste by milling is also analyzed. After extraction, the solution is filtered to separate an aqueous solution that contain the extracted Al3+ and a residual waste. A maximum of 7.54 g/dm3 of aluminum was extracted in the first step, for a total accumulated of 9.59 g/dm3 of aluminum. The extracted aluminum can be used to synthesize added-value products applied as adsorbents and catalysts. Finally, the residual waste generated was characterized by N2 adsorption at −196 °C, X-ray diffraction, X-ray fluorescence, energy-dispersive X-ray and scanning electron microscopy in order to apply it as in future works adsorbent or catalyst.The authors are grateful for financial support from the Spanish Ministry of Economy, Industry and Competitiveness (AEI/MINECO), the European Regional Development Fund (ERDF) and the Government of Navarra through projects MAT2016-78863-C2-1-R and PI017 CORRAL