Pilot-scale investigation of two Electric Pulse Fragmentation (EPF) approaches for the mineral processing of a low-grade cassiterite schist ore

BRU, SOUSA, LEITE, BROADBENT, STUART, PASHKEVICH, MARTIN, KERN, PARVAZ

KathyBrua RuiSousab MárioMachadoLeiteb ChrisBroadbentc GarfieldStuartc DzmitryPashkevichd MirkoMartind MariusKerne Daniel B.Parvazf

aBRGM, F-45060 Orléans, France

bLNEG National Laboratory of Energy and Geology, S. Mamede de Infesta, Portugal

cWardell Armstrong International, Wheal Jane Earth Science Park, Baldhu, Truro, Cornwall TR3 6EH, UK

dGEOS, Gewerbepark Schwarze Kiefern 2, 09633 Halsbrücke, Germany

eHelmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Chemnitzer Straße 40, 09599 Freiberg, Germany

fSELFRAG AG, Biberenzelgli 18, 3210 Kerzers, Switzerland

Minerals Engineering

ABSTRACT

Two approaches for the use of the Electric Pulse Fragmentation (EPF) in the beneficiation of a low-grade cassiterite schist ore were investigated through pilot-scale tests performed on samples of about 270 kg. The first approach used EPF treatment for pre-concentration while in the second approach the EPF technology was mostly used for crushing. Comparison with the use of conventional crushers was performed.

Results showed that the EPF pre-treatment led to a decrease of the Bond rod mill work index while the Bond ball mill work index remained unchanged. This means that the decrease in the energy consumption requested to grind the material down to 1.18 mm (closing screen of the Bond rod mill work index) is no longer noticeable with additional grinding stage to reach a size down to 106 µm (closing screen of the Bond ball mill work index). This may be due to the fracture network generated during EPF being consumed immediately in the subsequent comminution step.

Alternatively, it may be that the Bond ball mill work index is not appropriate for exhibiting the weakening effect of the EPF technology when the mineral liberation size is coarser than the closing screen size used for the test. Concentration tests performed on the sample treated with the first approach for EPF showed no marked change in separation performance. However, a higher concentrate grade was obtained when using this EPF pre-treatment, indicating a probable potential for improvement.

Keywords

Cassiterite, Electric Pulse Fragmentation, Selective comminution, Pre-concentration

Acknowledgements

This study was performed under the project FAME (‘Flexible And Mobile Economic processing technologies) which has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no 641650. The authors acknowledge the contributions of the FAME team for sample collection and scientific discussions that led to this paper. Provision of mineralogical data obtained through the German AFK Project funded within the r4-initiative of the BMBF (grant number 033R128) is also acknowledged.

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