Patent ID: 6412642
Filing Date: 2002-07-02
Classification: B07C,B21C,C22B,Y02P

Abstract:
In a method of sorting metal scrap comprising a mixture of scrap metal pieces respectively derived from metal stock of at least two different compositions, to separate the scrap metal pieces of a first of said compositions from the scrap metal pieces of a second of said compositions, said stock of each of said two compositions having a surface and being initially separate from the stock of the other of said two compositions, said scrap being generated and mixed during or after procedures performed on said stock of said two compositions, and said scrap metal pieces of each of said two compositions bearing portions of the surface of the stock from which they are derived, the steps of(a) prior to or during the performance of said procedures, while said metal stock of said first composition is separate from the metal stock of said second composition, selectively marking the surface of only the stock of said first composition to provide a detectable surface mark on said surface portions on said scrap metal pieces of said first composition after the performance of said procedures, such that said mark is present only on said scrap metal pieces of said first composition in said mixture, and (b) scanning the mixture of metal scrap to detect said mark on scrap metal pieces therein, and thereby to distinguish said scrap metal pieces of said first composition from other scrap metal pieces in said mixture.