Combination of X-ray transmission and eddy-current testing for the closed-loop recycling of aluminum alloys

In general, aluminum alloys at industrial end-of-life are considerably recycled into aluminum alloys, but they are mostly recycled as alloys for casting because their acceptable concentration limits are not strictly designated and not comparable with those of wrought alloys. This means that recycling from end-of-life wrought alloys to cast alloys has been practiced instead of closed-loop recycling from end-of-life wrought alloys to wrought alloys. The energy required for producing aluminum from recycled aluminum is only 5 % of the energy required for producing aluminum from bauxite. In addition, refining material into wrought aluminum alloys requires many primary aluminum ingots. In terms of saving energy and resources, it would be better if we could conduct closed-loop recycling from end-of-life wrought alloys to wrought alloys. In this study, a combination of X-ray transmission and eddy-current testing is examined with the aim of sorting wrought aluminum alloys. The seven types of wrought aluminum alloys were only sorted into three groups by using X-ray transmission testing and eddy-current testing, while they were sorted into six groups by using a combination of X-ray transmission and eddy-current testing.