Recent developments in microwave-assisted comminution

Kingman, S.W.; Jackson, K.; Cumbane, A.; Bradshaw, S.M.; Rowson, Neil A.; Greenwood, R.

doi:10.1016/j.minpro.2003.09.006

Cited by 127 publications

(50 citation statements)

References 7 publications

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“…However, these studies originally treated ball mill feed size material (<10mm) at low power (<3kW) in low power density multimode cavities for several minutes, resulting in very high energy inputs (>>10kWh/t) unsuitable for incorporation in a typical comminution circuit. Kingman et al (2004b) and Scott et al (2008) both tested the same copper ore investigated by Kingman et al (2000a) and demonstrated improved liberation after high power density microwave treatments on lump fragments (>10mm) in single mode cavities with up to 15kW microwave power at economically feasible energy inputs (0.1-5kWh/t). Furthermore, Sahyoun et al (2005) conducted flotation tests on the same ore and demonstrated a 3-6% increase in copper recovery after microwave treatment (up to 12kW and 1.7kWh/t on <22mm size material) as opposed to the 1% increase reported by Kingman et al (2000a), attributed to the higher power density sustained in the single mode cavity.…”

Section: Introductionmentioning

confidence: 90%

“…High power density microwave treatment has been proposed as a technique to reduce ore competency prior to beneficiation and as a means of enhancing liberation through the generation of thermally-induced cracks along mineral grain boundaries leading to inter-granular and trans-granular fracture (Kingman et al, 2004a;Kingman et al, 2004b;Kingman et al, 2000a). The efficacy of this mechanism and the amenability of ores to microwave-induced fracture has been shown to depend on the dielectric, thermal and mechanical properties of the minerals involved, their assemblage within the ores, and the microwave energy and power density applied Bradshaw, 2009, 2010;Jones et al, 2007;Kingman et al, 2000b;Wang et al, 2008;Wang and Djordjevic, 2014;Whittles et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

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

Jones

Plint

Kingman

2016

Minerals Engineering

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The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk Minerals Engineering 94 (2016) AbstractIn 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 15kW and approximately 2kWh/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 50-60µm 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 30µm 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 microwaveabsorbent mineral (pyrite) resulted in a significant change in liberation behaviour. Minerals Engineering 94 (2016) 61-752 http://dx

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Section: Introductionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

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

Jones

Plint

Kingman

2016

Minerals Engineering

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“…The underpinning mechanism and textural characteristics of amenable ores has been described by Batchelor et al (2015). Selective heating of microwave-absorbent sulphides and metal oxides deported in a microwave-transparent gangue matrix results in differential thermal expansion of the heated phase, yielding micro-fracture around grain margins Jones et al, 2005Jones et al, , 2007Kingman et al, 2004a;Kingman et al, 2004b;Kingman et al, 2000a). Subsequent downstream processing may then yield higher recovery of valuable mineral sulphides and/or lower specific comminution energy, compared to non-microwave treated ore.…”

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confidence: 99%

Towards large scale microwave treatment of ores: Part 1 – Basis of design, construction and commissioning

Buttress

Katrib

Jones

et al. 2017

Minerals Engineering

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Highlights A pilot scale system for microwave treatment of ores is presented  Materials handling concepts and justification for packed bed mass flow are discussed  Microwave applicator and choke modelling is validated against real ores  Control of material flow and presentation is discussed  The operating microwave treatment system performance is described AbstractDespite over thirty years of work, microwave pre-treatment processes for beneficiation of ores have not progressed much further than laboratory testing. In this paper we present a scaleable pilot-scale system for the microwave treatment of ores capable of operating at throughputs of up to 150tph. This has been achieved by confining the electric field produced from two 100kW generators operating at 896MHz in a gravity fed vertical flow system using circular choking structures yielding power densities of at least 6x10 8 W/m 3 in the heated mineral phases. Measured S11 scattering parameters for a quartzite ore (-3.69±0.4dB) in the as-built applicator correlated well with the simulation (-3.25dB), thereby validating our design approach. We then show that by fully integrating the applicator with a materials handling system based on the concept of mass flow, we achieve a reliable, continuous process. The system was used to treat a range of porphyry copper ores. Minerals Engineering 109 (2017) 169-832 http://doi.org/10.1016/j.mineng.2017.03.006 IntroductionMicrowave treatment of metalliferous ores has long been investigated as a means to enhance the recovery of valuable minerals and reduce the comminution resistance of ores (Chen et al., 1984;Walkiewicz et al., 1988;Walkiewicz et al., 1989). The underpinning mechanism and textural characteristics of amenable ores has been described by Batchelor et al. (2015). Selective heating of microwave-absorbent sulphides and metal oxides deported in a microwave-transparent gangue matrix results in differential thermal expansion of the heated phase, yielding micro-fracture around grain margins Jones et al., 2005Jones et al., , 2007Kingman et al., 2004a;Kingman et al., 2004b;Kingman et al., 2000a). Subsequent downstream processing may then yield higher recovery of valuable mineral sulphides and/or lower specific comminution energy, compared to non-microwave treated ore.While the mechanistic principles are well established, the scientific and engineering challenges of developing a commercial scale system are immense. Typical throughputs of a large copper mine can be in excess of 5,000 tph of milled ore (Brininstool, 2015) and a microwave based treatment system would need to handle equivalent throughputs. This is at least an order of magnitude higher than any other microwave process ever built.The following paper details the design, commissioning and operation of a system which was the culmination of over fifteen years of research and development activity. This resulted in a high power microwave treatment process, capable of operating continuously at throughputs of up to 150tph, but crucially, scaleable up to several th...

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“…Kingman et al, 2004 34 , investigated the treatment of a copper carbonatite ore from a mine in South Africa using a single mode, high power applicator (i.e. a variable power input of up to 15 kW).…”

Section: Microwave Assisted Ore Grindingmentioning

confidence: 99%