ABSTRACT Rare earth elements are increasingly seen as critical raw materials and are currently the subject of geopolitical interests. To boost mineral exploration and extraction, it is important to ensure the rapid identification and mapping of rare earth elements, and non‐invasive spectroscopy‐based technologies could offer suitable solutions. We therefore investigated the potential of an integrated sensor system that combines hyperspectral and laser‐induced fluorescence imaging as a non‐invasive alternative characterization technique to conventional time‐consuming and costly chemical analysis. To test the analytical procedure we used representative material from the Siilinjärvi mine (Finland) and from Lofdal (Namibia). Laser‐induced fluorescence mapping results document the successful identification and efficient mapping of several rare earth elements within complex mineral matrices. The variation in laser‐induced fluorescence excitation wavelength facilitates the selective mapping of specific rare earth elements, thereby enhancing their differentiation capabilities. The combination with hyperspectral imaging provides mineral maps and cross‐validation. The major benefit of the integrated optical sensor system lies in the rapid acquisition of spatially continuous information on the occurrence and type of rare earth elements without the need for sample preparation. The non‐destructive character and operation in line‐scan mode opens manifold possibilities for in‐line applications with continuous sample throughput.
Abend et al. (Sun,) studied this question.