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Application of Raman spectroscopy to identification and sorting of post-consumer plastics for recycling

United States Patent

November 6, 2001
View the Complete Patent at the US Patent & Trademark Office
A high accuracy rapid system for sorting a plurality of waste products by polymer type. The invention involves the application of Raman spectroscopy and complex identification techniques to identify and sort post-consumer plastics for recycling. The invention reads information unique to the molecular structure of the materials to be sorted to identify their chemical compositions and uses rapid high volume sorting techniques to sort them into product streams at commercially viable throughput rates. The system employs a laser diode (20) for irradiating the material sample (10), a spectrograph (50) is used to determine the Raman spectrum of the material sample (10) and a microprocessor based controller (70) is employed to identify the polymer type of the material sample (10).
Sommer; Edward J. (Nashville, TN), Rich; John T. (Lebanon, TN)
National Recovery Technologies, Inc. (Nashville, TN)
09/ 284,955
July 14, 1999
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT The invention was made with the support of the United States Government under Contract No. DE-FG02-95ER82038 awarded by the U.S. Department of Energy. Therefore, the United States Government has certain rights in the invention. The present invention has been the subject of the aforementioned provisional application in the United States as well as an application for a grant from the United States Department of Energy (Application No. 35343-95-I). The contents of these two documents are herein incorporated by reference, in their entireties.