Microwave Pretreatment for Thiourea Leaching for Gold Concentrate

Choi, Nag-Choul; Kim, Bong Ju; Cho, Kanghee; Lee, Soonjae; Park, Cheon Young

doi:10.3390/met7100404

Cited by 28 publications

(10 citation statements)

References 29 publications

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“…Sunshin mine has been developed since January 2002 with production from Eunsan deposit, and the production of Moisan deposit was followed in 2006. The combined mine production from the two deposits up to April 2008 was 1222 kg Au and 31,058 kg Ag [27][28][29].…”

Section: Ore In the Near-surface Oxide Zonementioning

confidence: 99%

“…RMR processing was conducted as a pre-processing to separate the Fe-oxides from the auriferous ore in the near-surface oxide zone. The microwave roasting process, especially controlling irradiation time, could be used to control the mineral phase change of ore sample [29]. For the reduction of hematite, various reducing agents, such as activated carbon, sodium carbonate and charcoal, have been used in the reductive roasting process [30][31][32].…”

Section: Rmr Processmentioning

confidence: 99%

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Effective Gold Recovery from Near-Surface Oxide Zone Using Reductive Microwave Roasting and Magnetic Separation

Kim

Cho

Lee

et al. 2018

Metals

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High content of gold in near-surface oxide zones above the gold ore deposit could be recovered using cyanidation. However, restricting the use of cyanide in mines has made it difficult to recover gold within the oxide zone. In this study, we investigated an application of the reductive microwave roasting and magnetic separation (RMR-MS) process for the effective gold recovery from ores in a near-surface oxide zone. Ore samples obtained from the near-surface oxide zone in Moisan Gold Mine (Haenam, South Korea) were used in RMR-MS tests for the recovery of iron and gold. The effect of the RMR process on the recovery of iron and gold was evaluated by given various conditions of the microwave irradiation as well as the dosages of reductant and additive. The microwave roasting resulted in a chemical reduction of non-magnetic iron oxide minerals (hematite) to magnetite minerals, such as magnetite and maghemite. This mineral phase change could induce the effective separation of iron minerals from the gangue minerals by magnetic separation process. The increased iron recovery was directly proportional to the gold recovery due to the coexistence of gold with iron minerals. The RMR-MS process could be a promising method for gold recovery from the ores in near-surface oxide zones.

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Section: Ore In the Near-surface Oxide Zonementioning

confidence: 99%

Section: Rmr Processmentioning

confidence: 99%

Effective Gold Recovery from Near-Surface Oxide Zone Using Reductive Microwave Roasting and Magnetic Separation

Kim

Cho

Lee

et al. 2018

Metals

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“…La tostación es una técnica muy utilizada para tratar minerales carbonáceos de oro, debido a que es una técnica económica, de alta eficiencia y bastante desarrollada. Mediante la tostación oxidativa no solo se oxidan los componentes carbonáceos a dióxido de carbono, sino que también mediante la desulfuración y desarcenización se destruyen minerales como pirita y arsenopirita que contienen oro encapsulados, y exponen las partículas de oro finamente diseminadas al cianuro durante la lixiviación [10][11][12][13][14]. Por lo tanto, el propósito de la tostación es eliminar los elementos nocivos de los minerales y formar calcina porosa, de modo que el oro se pueda lixiviar eficazmente durante la cianuración.…”

Section: Introductionunclassified

Tratamiento de un mineral aurífero carbonáceo mediante lixiviación oxidativa-tostación y tostación directa

González¹,

Rodriguez²,

Gutierrez³

et al. 2021

The 1st LACCEI International Multi-Conference on Entrepreneurship, Innovation, and Regional Development: “Ideas to Overcome And

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A carbonaceous gold refractory mineral was studied. The characterization of the sample was carried out by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), FTIR, Leco SC and oxidative leaching. The chemical analysis presents 9.83 g/t Au, the mineralogical 24.03% of fixed carbon (Leco SC). The Preg-robbing tests show that the mineral adsorbs 94.34% of gold from the solution in 30 minutes and the recovery of gold in the conventional cyanidation test was 3.36% in 24 hours with granulometry 80% through mesh N ° 200, this reveals the high degree of refractoriness of the mineral. The results of oxidative leachingroasting and direct roasting tests in conjunction with the mineralogical analysis of the mineral suggest that refractory gold is mainly associated with carbonaceous material. The oxidative process with HCl and cyanidation only allows the recovery of 8.15% of gold, generated by the liberation of gold from carbonates; while, through the oxidative process with HNO3 and cyanidation, the recovery was even lower than only 2.20% of gold. The residues of the oxidative process were subjected to roasting at 800 ° C and a 25.42% recovery of gold was obtained. This low recovery was probably due to the high roasting temperature that produced a mineralogical transformation,where the mineral formed Ca6O19Si6 and Ca2MgO7Si2 could re-trap the released gold, reducing its recovery during cyanidation. The results of the direct roasting of the mineral at 500 °C, 600 °C and 700 °C, show that the mineral presents 22.83 ± 0.56% loss of mass at 700 °C, very close to the value of fixed carbon and at this temperature it was obtained the highest gold recovery of 91.06 ± 0.31%, which confirms that gold is associated with carbonaceous material.

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“…Until now, the widely used Au test methods include titration (Stefano et al 2015), atomic absorption spectrometry (Yilmaz and Soylak 2014;Choi et al 2017;Zhou et al 2017;Tang et al 2019), inductively coupled plasma optical emission spectroscopy (George and Konstantinos 2016;Hassan et al 2016;Xue et al 2016), microwave plasma atomic emission spectrometry (Balaram et al 2013), and inductively coupled plasma mass spectrometry (ICP-MS) (Liu et al 2013;Tao et al 2017;Satyanarayanan et al 2018;Chen et al 2019). Among them, ICP-MS meets the test conditions of most geological samples and has the advantages of low detection limit, high sensitivity, and wide linear range (Qi et al 2011;Resano et al 2012;Yim et al 2012;Strnad et al 2016;Berezhnaya and Dubinin 2017).…”

Section: Introductionmentioning

confidence: 99%

Gold determination in soil by ICP-MS: comparison of sample pretreatment methods

Tang

et al. 2020

J Anal Sci Technol

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At present, the direct gold determination in geological samples by inductively coupled plasma mass spectrometry (ICP-MS) is still an arduous challenge due to both spectral and background interferences. It is very important and necessary to study the pretreatment processes; therefore, the polyurethane foam treatment and sample digestion methods are explored and compared here. The experimental results showed that the gold adsorption rate of treated foam was significantly improved as the impurities in the foam were cleaned up, and the potential difference of the liquid membrane was increased. Meanwhile, the combination of the foam enrichment and thiourea desorption achieved the selective adsorption and desorption of gold ions, eliminated the interference of coexisting ions, and perfected the detection limits. Compared with the traditional electric heating plate digestion method, microwave digestion, a closed digestion method, had the advantages of less sample and reagent dosage, short time consumption, high degree of automation, thorough digestion, good security, and environmental friendliness and met the requirements of green chemistry development. The proposed microwave digestion-foam enrichment-thiourea desorption-ICP-MS determination method was applied to the gold test in soil samples of the actual gold mining area. It has the great potential as a routine laboratory procedure.

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Microwave Pretreatment for Thiourea Leaching for Gold Concentrate

Cited by 28 publications

References 29 publications

Effective Gold Recovery from Near-Surface Oxide Zone Using Reductive Microwave Roasting and Magnetic Separation

Effective Gold Recovery from Near-Surface Oxide Zone Using Reductive Microwave Roasting and Magnetic Separation

Tratamiento de un mineral aurífero carbonáceo mediante lixiviación oxidativa-tostación y tostación directa

Gold determination in soil by ICP-MS: comparison of sample pretreatment methods

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