• Title/Summary/Keyword: gold 용출

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Optimization of Gold Leaching from the Refractory Sulfide Concentrate by HCl-NaClO-FeCl3 Solution (HCl-NaClO-FeCl3 용액을 이용한 저항성 황화광물 정광으로부터 금 용출 최적화)

  • Kim, Bong-Ju;Cho, Kang-Hee;Lee, Jong-Ju;Choi, Nag-Choul;Park, Cheon-Young
    • Economic and Environmental Geology
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    • v.46 no.1
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    • pp.21-28
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    • 2013
  • In order to optimize gold leaching from refractory sulfide concentrate, a HCl-NaClO-$FeCl_3$ solution with varying attributes was applied to the roasted concentrate from Uil mine. The gold from Uil mine occurs in the form of invisible gold that is difficult to leach. The results of the gold leaching experiments showed that the best gold leaching parameters were $550^{\circ}C$ of roasting temperature, 2.0 M of concentration, 1.0% of pulp density, and $70^{\circ}C$ of leaching temperature. It is confirmed that the HCl-NaClO-$FeCl_3$ solution was an environmentally friendly method to leach gold and silver from the refractory sulfide concentrate as an alternative lixiviant to cyanide.

The Leaching of Gold-silver from Refractory Gold Concentrate by Chlorine-hypochlorite Solution (염소-차아염소산 용액에 의한 저항성 금 정광으로부터 Gold-silver 용출)

  • Cho, Kang-Hee;Kim, Bong-Ju;Oh, Su-Ji;Choi, Seoung-Hwan;Choi, Nag-Choul;Park, Cheon-Young
    • Journal of the Mineralogical Society of Korea
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    • v.25 no.3
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    • pp.123-130
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    • 2012
  • Leaching experiments of gold and silver from roasted concentrate were carried out using a chlorine-hypochlorite solution. The leaching rate of gold was 75% at 1.5:1 ratio of chlorine and hypochlorite and increased to 81% with adding 1 M NaCl. However, at 1% pulp density and at $65^{\circ}C$, the leaching rates of Au were close to 100%. XRD analysis identified quartz in the solid residues after digestion of roasted concentrate with aqua regia or chlorine-hypochloride leaching solution. This suggests that the gold may not be leached out of the quartz in aqua regia or chlorine-hypochlorite solution. In order to leach the gold from the quartz, the concentrate will have to be pre-treated through ultra-fine grinding or treated with stronger oxidative agents.

Gold Recovery from Geumsan Concentrate Using Microwave-nitric Acid Leaching and Lead-fire Assay (마이크로웨이브-질산용출과 납-시금법을 이용한 금산정광으로부터 금 회수)

  • Lee, Jong-Ju;On, Hyun-Sung;Park, Cheon-Young
    • Journal of the Mineralogical Society of Korea
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    • v.32 no.2
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    • pp.113-126
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    • 2019
  • This study aimed to effectively dissolve sulfide minerals through microwave-nitric acid leaching of invisible gold concentrate and then recover gold from the solid-residue with fire assay. For the purposes, this study conducted microwave-nitric acid leaching experiments to examine nitric acid concentration, time of microwave leaching, and sample addition effect. As results of the experiments, this study discovered that the weight loss rate of solid-residue increased as nitric acid concentration and microwave leaching time increased while weight loss rate decreased as sample addition increased. In an XRD analysis with solid-residue, it was discovered that pyrite completely disappeared when the nitric acid concentrate was 6 M and the microwave leaching time was 18 minutes. When a fire assay was carried out with solid-residue, gold particles with more content were recovered as nitric acid concentration and microwave leaching time increased whereas gold particles with more gold content were recovered as the sample addition decreased.

The Dissolution Efficiency of Gold Concentrate with Microwave-nitric Acid Leaching and the Recovery of Invisible Gold Using the Filter Paper (마이크로웨이브-질산용출에 의한 금 정광의 용해효율과 여과지를 이용한 비-가시성 금 회수)

  • Lee, Jong-Ju;Park, Cheon-Young
    • Economic and Environmental Geology
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    • v.52 no.6
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    • pp.595-604
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    • 2019
  • The purpose of this study was simply to obtain gold through a microwave-nitric acid experiment of invisible gold concentrate with the use of filter paper. For the purpose, this study conducted a microwave-nitric acid leaching experiment and examined nitric acid concentration. As a result of the experiment, this study discovered that Fe, Te and Ag were completely leached in the leaching solution whereas Au was not determined in all of the nitric acid conditions. The leaching solution was filtered with three filter papers and then these filter papers were analyzed with SEM/EDS. As a result of the EDS analysis, Au was detected in all of the surface and cross-section of the 1st, 2nd and 3rd filter papers. As the three filter papers containing solid-residue were analysed in the lead-fire assay, gold particles were found in all of the nitric acid conditions. In the lead-fire assay, maximum gold(452.50g/t) was recovered when nitric acid concentration was 6M and microwave leaching time was 12mins.

The Selection Effect of Native Gold and Magnetite by Microwave-nitric Acid Leaching and Magnetic/hydro Separation (마이크로웨이브-질산용출과자력/수력선별에의한자연금및자철석의선별효과)

  • Lee, Jong-Ju;Park, Cheon-Young
    • Economic and Environmental Geology
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    • v.53 no.2
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    • pp.183-196
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    • 2020
  • This study aimed to recover native gold from the concentrate using microwave-nitric acid leaching and magnetic/hydro separation experiments. The insoluble-residue was filtered from leaching solution through microwave-nitric acid leaching experiment. As a result of the atomic absorption spectrometer(AAS) analysis of the filtered leaching solution, it was discovered that Au content was not eluted at all and it was observed from the back scattered electron(BSE) image that native gold was liberated in the insoluble-residue. When magnetic/hydro separation experiments were applied for the insoluble-residue, magnetic and non magnetic minerals were separtated from insoluble-residue. Magnetite was recovered from the magnetic minerals and as a result of applying the hydro separation experiment again for the non-magnetic mineral, native gold was recovered. The native gold was identified through the X-ray diffraction(XRD) analysis and BSE image.

Mineralogical Phase Transform of Salt-roasted Concentrate and Enhancement of Gold Leaching by Chlorine-hypochlorite Solution (소금-소성정광에 대한 광물학적 상변화와 염소-차아염소산 용액을 이용한 금 용출 향상)

  • Kim, Bong-Ju;Cho, Kang-Hee;Oh, Su-Ji;Choi, Seoung-Hwan;Choi, Nag-Choul;Park, Cheon-Young
    • Journal of the Mineralogical Society of Korea
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    • v.26 no.1
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    • pp.9-18
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    • 2013
  • In order to optimize the gold leaching process from refractory sulfide concentrate, a chlorine-hypochlorite solution with varying concentrations and temperatures were applied to salt-roasted concentrate. The concentrate consisted of pyrite, chalcopyrite, and galena, which were turned into hematite through air-roasting at $750^{\circ}C$. Also these concentrates were changed into hematite and nantokite (CuCl)) through salt (NaCl)-roasting at $750^{\circ}C$. The results of the gold leaching experiments showed that the best gold leaching parameters were obtained when the hydrochloric acid-sodium hypochlorite mix was at a ratio of 1 : 2, the added concentration was 1.0 M concentration, the pulp density was 1.0%, and the leaching was done at a $60^{\circ}C$ leaching temperature. The leaching rate for gold was much greater in the roasted concentrate than in the raw concentrate. The leaching rate was greater in the salt-roasted concentrate than in the plain roasted concentrate too. From XRD analysis, quartz was found in the salt-roasted concentrate and in the solid residue from the chlorine-hypochlorite leaching solution at $60^{\circ}C$.

Improvement of Au Leaching from Gold Concentrates Using a Microwave and Thiourea-mixed Solvent (마이크로웨이브를 이용한 금정광 내 금 용출 효율 증가 기작)

  • Kim, Bong-Ju;Kwon, Jang-Soon;Koh, Yong-Kwon;Park, Cheon-Young
    • Economic and Environmental Geology
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    • v.53 no.2
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    • pp.159-166
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    • 2020
  • In this research, we investigate the effect of microwave pretreatment on the recovery of gold from the gold concentrates by thiourea leaching. The changes in mineral phases by decomposition of pyrites in the gold concentrates using microwave were observed, and the result of microwave irradiation showed that the temperature of the irradiated sample increases with increasing irradiation time. With the reaction of temperature increases, Sulfur (S) in pyrites was converted to sulfur dioxide (SO2), and then the content of S in the sample was reduced. The analytical results of XRD and SEM-EDS showed that pyrites are converted to magnetite and hematite, and its surfaces are changed to a porous shape where micro-cracks are developed. The Au leaching efficiency from the irradiated gold concentrates using thiourea-mixed solvent increased with the increases of irradiation time and solvent concentration. The experimental results considering leaching parameters indicate that the mechanism of microwave irradiation increases the maximum leaching efficiency and leaching rate of the gold concentrates, and the solvent does a role for the increasing of leaching rate constant.

The Efficiency of Fe Removal Rate from Gold Ore in the Oxidation Zone by Ammonia Leaching (암모니아 용출에 의한 산화대 금 광석으로부터 Fe 제거 효율에 관한 연구)

  • Kim, Bong-Ju;Cho, Kang-Hee;Choi, Nag-Choul;Park, Cheon-Young
    • Journal of the Mineralogical Society of Korea
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    • v.29 no.3
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    • pp.113-122
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    • 2016
  • This study aims to improve the recovery of gold and silver by removing hematite from gold ore of an oxidation zone with ammonia solution. Quartz, hematite and muscovite were present in the oxidation zone, while hematite was hydrogenous. As a result of performing an ammonia leaching test on variables, it is found that the maximum Fe leaching parameter was $-45{\mu}m$ particle size, 1.0 M sulfuric acid concentration, 5.0 g/l ammonium sulfate concentration and 2.0 M hydrogen peroxide concentration. It is also confirmed that goethite was precipitated and formed from that ammonia elution. As the amount of Fe-removal was increased in a solid-residue, the recovery of Au and Ag were increased, too.

Mineralogical Transformation of Gold-silver Bearing Sulfide Concentrate by Mechanochemical Activation, and their Gold-silver Leaching with Non-cyanide Solution (기계적-화학적 활성화에 따른 금-은-정광의 광물학적 상변화와 비-시안 용매에 의한 금-은 용출 향상)

  • Kim, Bong-Ju;Cho, Kang-Hee;Oh, Su-Ji;Choi, Nag-Choul;Park, Cheon-Young
    • Journal of the Mineralogical Society of Korea
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    • v.27 no.3
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    • pp.115-124
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    • 2014
  • In order to leach Au and Ag from gold-silver bearing sulfide concentrate, the sulfide concentrate was ground in a ball mill for a dry pre-treatment and a wet pre-treatment process. Mineralogical studies and thiourea leaching experiments were carried out with the pre-treated sulfide concentrate. The results of the pre-treatment with the concentrate samples showed the mean particle size and iso-electrical potential was smaller in the dry pre-treatment sample than in the concentrate sample, and the contents was lower in the wet pre-treatment sample than in the dry pre-treatment sample. In XRD analysis, amorphous properties were only shown in the wet pretreatment sample. The results of the concentrate sample leaching experiments showed that the best Au, Ag leaching parameters were when the addition of thiourea was at a 1.0 g concentration, ferric sulfate was 1.0 M, sulfuric acid was 2.0 M and the leaching temperature was at $60^{\circ}C$. The Au, Ag leaching rate was always much greater and faster with the wet pre-treatment samples than with the dry pre-treatment samples. Accordingly, it is expected that more Au, Ag can be leached in an eco-friendly methodology using wet pre-treatment. The pre-treatment could be improved with an optimized grinding additive reagent and through researching grinding time in future non-cyanide processes.

The Characteristic of Te Recovery in Gold Concentrate Using Electrolysis (전기분해법을 이용한 금정광내 Te 회수 특성)

  • Kim, Bong-Ju;Cho, Kang-Hee;Jo, Ji-Yu;Choi, Nag-Choul;Park, Cheon-Young
    • Economic and Environmental Geology
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    • v.47 no.6
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    • pp.645-655
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    • 2014
  • In order to obtain pure metallic Te from gold concentrate, roasting treatment, hypochlorite leaching, Fe removal and electrolysis experiments were carried out. The contents of Au, Ag and Te from the concentrate sample and roasted sample were much more soluble in the hypochlorite solution than in aqua regia digestion, whereas the metals Pb, Zn, Fe and Cu were easier to leach with the aqua regia than the hypochlorite. With the addition of NaOH in the hypochlorite leaching solution prior to electrolysis, the Fe removal rate achieved was only 96% in the concentrate sample, while it reached 98% in the roasted sample. The results of electrolysis for 240 min, 98% of the metallic copper was recovered from the concentrate sample, while 99% was obtained from the roasted sample due to the removal of S by roasting. The amount of anode slime was also greater in the electrolytic solution with the roasted sample than with the concentrate sample. The results on the anode slime after the magnetic separation process showed the amount of metallic pure native tellurium recovered was greater in the roasted sample than in the concentrate sample.