The feasibility of CO₂‐laser‐induced breakdown spectroscopy for fast lead determination in glass cullet

Abstract With an overall collection and recycling rate of 74%, the material cycle for glass packaging is well established in the European Union. However, knowledge of the composition of the recycled glass cullet is necessary to avoid creeping accumulation of undesirable contaminants into the material cycle. Due to their toxic properties, this applies in particular for heavy metals, for example, lead. The state‐of‐the‐art technology for detection of lead in recycling glass sorting is X‐ray fluorescence (XRF). Due to lower regulatory demands, as well as increasingly economical hardware, laser‐based detection techniques, like Laser‐Induced Breakdown Spectroscopy (LIBS) may provide an alternate approach in industrial glass sorting to reach comparable detection limits and rates. In our work, CO ₂ ‐LIBS was investigated as an alternative tool for the determination of lead in glass cullet. Instead of usually utilized spectrometers, a combination of spectral filters and photodiode was employed to facilitate a fast detection rate. Glass samples with different lead content were investigated in two spectral ranges with respect to detection limits, detection speed, and accuracy. The results are compared to a commercial XRF‐sorting machine for glass cullet. It was found that comparable speeds and accuracies for lead detection in glasses can be reached.