Volume 15, Issue 4 (July 1987)
Large-Scale Metals Identification and Sorting Using Instrumented Techniques
The U.S. Bureau of Mines is studying methods for the identification of scrap metals that will lead to better segregation, conservation of strategic materials, and utilization of this existing secondary reserve. A joint scrap segregation-marketing test is being conducted by the Bureau of Mines and the Defense Property Disposal Service at the Defense Property Disposal Office at Cherry Point, North Carolina. The purpose of the test is to determine the cost effectiveness of offering well-segregated metallic scrap fractions for sale.
Thus far, approximately 250 000 kg of aircraft scrap have been identified and sorted by a combination of conventional and instrumental techniques into 30 categories with better than 95% accuracy at a manual sorting rate averaging 93 kg/man-h. Techniques used in this study included fluorescent X-ray spectrography, thermoelectric response, optical spectroscopy, spark testing, magnet testing, and object recognition. The practical application of these techniques in a large-scale test is described.