Improved grindability and gold liberation by microwave pretreatment of a free-milling gold ore

Amankwah, R.K.; Khan, Ahsan U.; Pickles, C.A.; Yen, W.T.

doi:10.1179/037195505x28447

Cited by 51 publications

(27 citation statements)

References 7 publications

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“…Furthermore, there is an increasingly urgent need for the historically risk-averse mining industry to innovate and establish less water and energy intensive processes, leading to it being identified as the third highest risk for copper mining (tenth for all mineral commodities) (EY, 2014). Several authors have demonstrated improved liberation on copper sulphide, iron sulphide and native goldcontaining ores after microwave treatment and subsequent grinding (Amankwah et al, 2005;Andriese et al, 2012;Wang and Forssberg, 2005). Other studies have also demonstrated increased flotation recovery and concentrate grade attributed to enhanced liberation due to microwave-induced fracture on copper, lead-zinc and nickel sulphide ores (Henda et al, 2005;Kingman et al, 2000a;Kumar et al, 2006;Orumwense and Negeri, 2004;Vorster et al, 2001).…”

Section: Introductionmentioning

confidence: 98%

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: 98%

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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“…Amankwah et al, 2005 35 , performed tests on samples of a gold ore containing quartz, silicates and iron oxides with a head grade of 6.4 g/t of gold, using 2 kW of power in a multimode cavity. It was seen that the microwave treatment resulted in a maximum reduction of 31.2% in crushing strength and a reduction of 18.5% in work index.…”

Section: Microwave Assisted Ore Grindingmentioning

confidence: 99%

“…It was suggested that the increase in copper recovery with microwave leaching was due to localized higher temperatures around the outer shell of the leaching solution as a result of the high dielectric loss factor (and thus low penetration depth) of the solution, and also selective heating of the outer skin of the chalcopyrite particles due to the high conductivity of this material. 55 , performed tests on samples of a gold ore containing quartz, silicates and iron oxides with a head grade of 6.4 g/t of gold, using 2 kW of power in a multimode cavity. It was seen that the microwave treatment resulted in a maximum reduction of 31.2% in crushing strength and a reduction of 18.5% in work index.…”

Section: Microwave Assisted Pretreatment Of Refractory Gold Concentratementioning

confidence: 99%

Microwave Heating Applications in Mineral Processing

Koleini¹,

Barani²

2012

The Development and Application of Microwave Heating

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“…This is because pyrite is a hyperactive mineral that absorbs microwaves well, while quartz is a mineral that is transparent to microwaves, so that only pyrite reacted with microwaves and thermally decomposed selectively. The occurrence of the diffraction lines of hematite and pyrrhotite in the pretreated sample after microwave irradiation suggests the mineral phase of pyrite was changed into that of hematite and pyrrhotite [9,13,28]. Mineralogical phase change of pyrite is possible at 750 • C [11,[29][30][31].…”

Section: Mineralogical Change In Gold Concentrate By Microwave Irradimentioning

confidence: 99%

“…Ma et al [12] studied the microwave treatment for the removal of sulfur and arsenic in Au concentrate. Amankwah and Pickles [13] reported the use of microwaves as a pretreatment process for gold recovery from carbonaceous sulfide concentrate by cyanide leaching. However, few studies have explained the relationship between the microwave irradiation and the enhancing leaching efficiency of Au from the gold concentrate.…”

Section: Introductionmentioning

confidence: 99%

Microwave Pretreatment for Thiourea Leaching for Gold Concentrate

Choi

Kim

Cho

et al. 2017

Metals

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Abstract:In this research, we studied the use of microwave pretreatment to enhance the efficiency of Au leaching from gold concentrate. The gold concentrate was pretreated using microwaves with different irradiation time. The sample temperature was increased up to 950 • C by the microwave irradiation. A scanning electron microscope-energy dispersive spectrometer showed the evolution of microcracks and the reduction of sulfur on the mineral surface. X-ray diffraction data also showed the mineral phase shift from pyrite to hematite or pyrrhotite. A leaching test was conducted for the microwave-treated and untreated gold concentrates using thiourea. Although the thiourea leaching recovered 80% of Au from the untreated concentrate, from the treated concentration, the Au could be recovered completely. Au leaching efficiency increased as the microwave irradiation time increased, as well as with a higher composition of thiourea.

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Improved grindability and gold liberation by microwave pretreatment of a free-milling gold ore

Cited by 51 publications

References 7 publications

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

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

Microwave Heating Applications in Mineral Processing

Microwave Pretreatment for Thiourea Leaching for Gold Concentrate

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