Increasing the grind size for effective liberation and flotation of a porphyry copper ore by microwave treatment

Batchelor, A.R.; Jones, D.A.; Plint, S.; Kingman, S.W.

Abstract

In this paper, mineralogy, grain size, dissemination, textural consistency and mineral associations were determined for a commercially exploited porphyry copper ore using a Mineral Liberation Analyser (MLA). The ore was subjected to high power density microwave treatments in a single mode cavity at 15 kW and approximately 2 kW h/t. The untreated and microwave-treated samples were subsequently milled to two grind sizes near the nominal plant grind size and a size-by-liberation analysis performed. The analysis revealed that equivalent liberation could be obtained at a grind size approximately 50–60 μm coarser than the nominal plant grind due to the microwave treatment. Flotation testing indicated that an increase in copper recovery of approximately 1% could be achieved, or that a grind size increase of approximately 30 μm may potentially yield equivalent copper recovery due to the microwave-enhanced liberation observed. However, statistical analyses demonstrated that it is difficult to attain confidence in recovery increases of approximately 1% even when conducting batch flotation tests in triplicate. The ore under investigation had previously been shown to produce only modest average reductions in strength (∼8%) under similar microwave treatment conditions due to a prevalence of many unfavourable textures. However, the preferential association of copper minerals with a hard matrix mineral (quartz) and a hard microwave-absorbent mineral (pyrite) resulted in a significant change in liberation behaviour.

Citation

Batchelor, A., Jones, D., Plint, S., & Kingman, S. (2016). Increasing the grind size for effective liberation and flotation of a porphyry copper ore by microwave treatment. Minerals Engineering, 94, https://doi.org/10.1016/j.mineng.2016.05.011

• Journal Article Type: Article
• Acceptance Date: May 13, 2016
• Online Publication Date: May 26, 2016
• Publication Date: Aug 1, 2016
• Deposit Date: May 26, 2016
• Publicly Available Date: May 26, 2016
• Journal: Minerals Engineering
• Print ISSN: 0892-6875
• Electronic ISSN: 0892-6875
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 94
• DOI: https://doi.org/10.1016/j.mineng.2016.05.011
• Keywords: Microwave; Ore; Mineralogy; Liberation; Flotation
• Public URL: https://nottingham-repository.worktribe.com/output/975378
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S0892687516301315