Spooner, Tsiminis, Moffatt, Payten, Teixeira, Klantsataya, de Prinse, Smith^, Ottaway

Presented at the Preconcentration Digital Conference November 2020

ABSTRACT

Single wavelength fluorescence sensing has been used in the preconcentration of ores for many years in situations where it is typically specific to the mineral of interest. Examples of fluorescence sensing include the sorting of diamonds in diamond mines and the sorting of scheelite in tungsten ores. However, the number of minerals that show useful single wavelength fluorescence properties in the visible spectrum is relatively small, so the application of fluorescence sensing is currently limited to niche application in the minerals industry.

Recent developments at the University of Adelaide have focussed upon extending fluorescence signal measurements into the infrared spectrum, as well as investigating multi-wavelength fluorescence known as up-conversion fluorescence. These techniques may not only significantly increase the number of minerals that exhibit fluorescence properties suitable for both identification and sensor-based sorting, but also provide mineral-specific signatures of higher quality than previously attainable.

This paper details the research work carried out by the University of Adelaide and funded by CRC ORE to develop a mineral-specific fluorescence sensor. The sensor targets two fluorine bearing minerals, fluorite and fluorapatite, that are common in many base metal ores such as porphyry copper ores and silver/lead/zinc ores. Fluorine is a known penalty element in mineral products derived from these ores, so mining companies need to monitor and control the amount of fluorine in their final product to keep it below commercially agreed specifications.

Currently there is no real time sensor capable of monitoring fluorine in the ore feed so monitoring and control is carried out using time-consuming standard sampling and off-line laboratory measurements. The development and application of a real time fluorine sensor will enable the mining companies to monitor and control fluorine levels in the plant, greatly reducing the time and cost associated with producing their mineral concentrates within the prescribed specifications.

AUTHORS

N A Spooner,^1,2,4 G Tsiminis,^1,2,3 J E Moffatt^1,2, T B Payten^1,2, L d S Teixeira^1,2, E Klantsataya¹, T J de Prinse¹, B W Smith⁴ and D J Ottaway^1,2,5

¹Institute for Photonics and Advanced Sensing, School of Physical Sciences, The University of Adelaide, Adelaide, South Australia, Australia, 5005

²CRC for Optimising Resource Extraction, PO Box 403, Kenmore, Queensland, Australia, 4069

³ARC Centre of Excellence for Nanoscale BioPhotonics School of Medicine, The University of Adelaide, Adelaide, South Australia, Australia, 5005

⁴Defence Science and Technology Group, Edinburgh, Adelaide, South Australia, Australia, 5111

⁵ARC Centre of Excellence for Gravitational Wave Discovery, OzGrav, The University of Adelaide, Adelaide, South Australia, Australia, 5005

ACKNOWLEDGEMENTS

The authors wish to acknowledge the CRC for Optimising Resource Extraction (ORE), the South Australian Museum, SA, and the Tate Museum, The University of Adelaide, SA, for providing samples for this study. This work was funded by the following: CRC for Optimising Resource Extraction grant (projects P1-005 & P1-014); Defence Next Generation Technology Fund grant Counter Improvised Threat (CIT) program (project CIT-186); Australian Government Research Training Program scholarships; Australasian Institute of Mining and Metallurgy Education Endowment Fund (EEF); and the ARC LIEF Scheme (grant LE140100042).

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