Fluorine can negatively interfere with leach and smelting processes during mineral processing1,2. Real-time knowledge of the concentration and mineral hosts of fluorine in a mineral processing ore stream is important to protect process line equipment and product. Currently only offline methods of detection are available. Online sensors that determine specific fluorine-bearing mineral concentration in real-time would enable improved efficiency in processing decisions during mine production.Common excitation wavelengths used for fluorescence studies in minerals frequently provide signals that are not clearly host-specific, and hence of limited utility for mineral identification. We show that upconversion fluorescence (UF), a process in which two or more photons are absorbed and one higher-energy photon is emitted, provides a more host-specific fluorescence output, minimising spurious signals in complex environments and therefore greatly improving detection thresholds. Natural samples of fluorite (CaF2), a major fluorine host at many mine sites, have been analysed by near-infrared excitation and have revealed UF from rare earth inclusions. UF was detected in samples with rare earth concentrations as low as 1 part per million, and is therefore considered a potential new sensing modality for real-time fluorite monitoring.

中文翻译：

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EXPRESS：天然存在的氟化钙中的上转换荧光

氟会对矿物加工过程中的浸出和冶炼过程产生负面影响 1,2。实时了解矿物加工矿石流中氟的浓度和矿物主体对于保护生产线设备和产品非常重要。目前只有离线检测方法可用。实时确定特定含氟矿物浓度的在线传感器将提高矿山生产过程中处理决策的效率。用于矿物荧光研究的常用激发波长经常提供不明确宿主特异性的信号，因此实用性有限用于矿物鉴定。我们展示了上转换荧光 (UF)，这是一种吸收两个或更多光子并发射一个更高能量光子的过程，提供更具宿主特异性的荧光输出，最大限度地减少复杂环境中的虚假信号，从而大大提高检测阈值。萤石 (CaF2) 的天然样品是许多矿场的主要氟宿主，已通过近红外激发进行分析，并揭示了稀土包裹体中的超滤。在稀土浓度低至百万分之一的样品中检测到超滤，因此被认为是实时萤石监测的潜在新传感模式。