Identification of Shredded Plastics in milliseconds using Raman spectroscopy for recycling

Raman spectroscopy is able to identify plastic components, similar to infrared absorption. This paper shows the potential application of Raman spectroscopy to post-consumer plastic recycling when massive and accurate sorting processes are required. We developed a high-speed Raman apparatus for scanning with an appropriate wavelength region of less as 1.5 milliseconds, and an analyzing methodology that uses a discrimination function. We successfully implemented this technique in a shredded plastic recycling plant. The online sensing system successfully carried out more than three hundred cycle decisions per second.