A Sorting System for Aluminum Alloy Scrap Based on Laser-Induced Breakdown Spectroscopy

Abstract

A sorting system for aluminum scrap using laser-induced breakdown spectroscopy (LIBS) has been developed, which employs the sequential sample cells that are moved by the electric actuator in order to carry scrap pieces. A combination of a Q-switched Nd: YAG laser (30mJ, 10ns) with an objective lens having a long focal length of 600 mm were used to generate plasmas, and the emitted light was analyzed spectroscopically by a compact fiber-optic spectrometer having a CCD array detector. A pulse generator was constructed in order to synchronize the laser pulse, the CCD spectrometer and the electric actuator. The elemental composition of aluminum alloy scrap was determined by the calibration curves obtained by analyzing the standard aluminum alloy samples. The sorting algorithm based on the difference of the concentration of main additional elements of aluminum alloy was proposed. The developed LIBS sorting system was applied for the analysis of aluminum alloy samples and complete classification and separation of cast and wrought aluminum alloys into specific alloy groups was achieved.