Recycling Aluminum Casting Alloy Scrap Using Molten Salt Electrolysis

Aluminum is an important base metal that is widely used in various industries owing to its excellent properties, such as light weight (2.7 g cm(-3)), high specific strength, and high corrosion resistance. However, the extraction and smelting process of aluminum from aluminum ore is extremely energy-intensive, such that significant attention is being given to aluminum recycling. Currently, approximately 1/3 of aluminum is supplied from aluminum scrap. However, the current aluminum recycling by remelting process is a downgrade approach because the alloying elements contained in the aluminum scrap cannot be efficiently separated hence enriches in the recycled aluminum. The high alloying concentration in the current recycled aluminum limits its application to aluminum casting alloys, which have much higher tolerable concentration for alloying elements than that of wrought alloys. To achieve an upgrade recycling of aluminum, in this study, separation of the silicon and copper, the two most important alloying elements in typical aluminum casting alloys, were carried out by using a molten salt electrolysis process.