Valorization of an Industrial Pollutant Residue as a Teaching Tool: Extraction of Al3+ from Aluminum Saline Slag

Aluminum is the most used non–ferrous metal. It can be recycled saving several natural resources, but generates large amounts of residues with a complex composition—still containing a valuable amount of aluminum, although also including contaminant compounds. The laboratory-scale valorization of an industrial aluminum residue is here used as a powerful didactic resource in Inorganic and Analytical Chemistry and related fields such as Chemistry, Chemical Engineering, Environmental Engineering, Materials Engineering, and related university degrees, since concepts like acid-base properties (particularly amphoterism), redox reactions, speciation diagrams, or solubility–precipitation concepts are applied. The students are encouraged to look for information on the topic, to teamwork, and to elaborate a well-written laboratory report. At the same time, this laboratory work introduces them to advanced laboratory techniques and to incorporate concepts of Circular Economy and various Sustainable Development Goals, educating the students with respect to the environment. Although focused on University studies, this manuscript also contains excellent ideas for secondary teachers to motivate STEM vocations, particularly for Chemistry and Chemical and Environmental Engineering, and is also ideal for being included in the preparation of future Secondary School teachers.