Comparative laboratory study of conventional and Electric Pulse Fragmentation (EPF) technologies on the performances of the comminution and concentration steps for the beneficiation of a scheelite skarn ore

*K. Bru, M. Beaulieu, R. Sousa, M. Leite, A, De Sousa, E. Kol, J. Rozenkranz, D. de Parvaz

Minerals Engineering

ABSTRACT

Electric Pulse Fragmentation (EPF) is an innovative technology that uses High-Voltage Pulsed Power (HVPP) for the selective comminution of a material. This paper aims to compare a beneficiation flowsheet including an EPF treatment in the comminution circuit to a conventional pathway where the EPF step was replaced by a series ofjaw crushers.

Tests were performed on a skarn ore containing scheelite as the main mineral of interest. This ore is characterized by a fine-grained mineralogy and represents a challenge to conventional comminution processing,requiring fine grinding to liberate the valuable minerals. Fine grinding has high energy requirements and generates large amounts of fines which can result in losses of the target mineral due to their removal before the concentration processes, especially in this case since scheelite is a brittle material.

Comparison of EPF treatment to mechanical crushing with a similar product size P80 (i.e. 80% passing size) showed that the EPF treatment led to a significant increase in WO3 content and distribution in the 0/250 μm size fraction suggesting a pre-concentration aspect to EPF treatment. Moreover, a marked improvement of the grindability of the ore treated at a discharged energy of 9.1 kWh/t was observed with values of 10.6 kWh/t compared to 14.5 kWh/t when conventional treatment was used.

Subsequent grinding and concentration steps confirmed the positive impacts of the fragmentation selectivity and pre-weakening effect of the EPF treatment. In particular, a reduction in fines production was observed after ball milling and a better concentrate grade was achieved for a similar recovery rate when an EPF treatment was included in the comminution pathway compared to the conventional one.

These results confirm the potential of the EPF treatment for improving the performances of the beneficiation processes of this scheelite-bearing skarn ore

Keywords

Scheelite, High voltage pulse, Electric pulse fragmentation, Selective comminution, Concentration

AUTHORS

Kathy Bru a,⁎, Mickaël Beaulieu a, Rui Sousa b, Mário Machado Leite b, Ana Botelho de Sousa b,Erdogan Kol c, Jan Rosenkranz c, Daniel B. Parvaz de

A BRGM, F-45060 Orléans, France

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

c Luleå University of Technology, Mineral and Metallurgical Engineering, SE-971 87 Luleå, Sweden

d SELFRAG AG, Biberenzelgli 18, 3210 Kerzers, Switzerland

e Lightning Machines Limited, 2nd Floor, Grove House, 774-780 Wilmslow Road, Didsbury, Greater Manchester M20 2DR

Principal authoer email Kathy Bru This email address is being protected from spambots. You need JavaScript enabled to view it.

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 the development of this paper

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