Laser technology for Ore analysis

The following Abstract was presented at Quebec Mines 2013. Innovation using new technology delivers measurable results.

Laser-induced breakdown spectroscopy (LIBS): A new tool for the mining industry

MOHAMAD SABSABI, PAUL BOUCHARD, FRANÇOIS DOUCET, LÜTFÜ ÖZCAN, ANDRÉ MOREAU, AISSA HARHIRA AND ALAIN BLOUIN (NRC)

The minerals industry is facing significant challenges – declining ore grades, increasingly complex ores with higher levels of impurities, and pressure to improve environmental performance leading to increased production costs. To meet these challenges, technologies are sought for online measurements that provide key analysis information at all steps, from mine to metal. In all the steps in the value chain, it is critical that operating parameters be adjusted and controlled so that the chemistry of the melt, the solution or the slurry is within predetermined limits. Presently, the complete turnaround time for sampling, sample transfer, analysis and communication of the results to the operators is often in the order of hours, or more. Virtually eliminating this delay by on-line Laser-Induced Breakdown Spectroscopy (LIBS) analysis will significantly increase productivity.

The LIBS technique offers the possibility of real-time analysis of multi-elements in mineral ore samples, thus allowing a fast on-line chemical analysis of these sam- ples. The LIBS technique uses a high-power pulsed laser whose beam is focused to produce a plasma on the sample to be analyzed. The light emitted by the plasma is analyzed with an optical spectrometer, and provides information on the chemical composition of the sample. An important advantage of the technique over classical methods stems from the possibility of in-situ analysis of virtually all types of materials (solids, liquids, molten materials and gases) with standoff capabilities, without the need for any sample preparation.

In our laboratory, LIBS has been used in various scientific and industrial applications, such as the analysis of metal alloys, liquids, and minerals. Its efficiency and robustness have been proven in many applications. LIBS can analyze a wide range of materials on site quickly, and detect quantities in the range of parts per million. In this presentation, we will present our results for the real-time analysis of molten metals and efflu- ents in metal processing, the on-line analysis of metal ore slurries and mineral ore samples, etc. In particular, we will be focusing on the application of LIBS for analyzing gold ore samples.

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