Automatic sorting of scrap metals with a combined electromagnetic and dual energy X-ray transmission sensor

The combination of an electromagnetic and a dual energy X-ray transmission sensor is a new method for automatic sorting of scrap non-ferrous metals. It allows classification of metals based on differences in electrical conductivity and atomic number. Both sensors were developed and tested at Delft University of Technology. In a number of experiments non-ferrous metals from post-shredder scrap were identified and sorted based on the combined sensor output. The results and possible industrial applications in automatic sorting of scrap metals are discussed. A sorting system that includes both sensors allows replacement of conventional ferro-silicon based dense medium systems by an entirely dry process that does not require any washing.