Direct Cupric Chloride Leaching of Gold from Refractory Sulfide Ore: Process Simulation and Life Cycle Assessment

Rinne, Marja; Elomaa, Heini; Seisko, Sipi; Lundström, Mari

doi:10.1080/08827508.2021.1910510

Cited by 14 publications

(5 citation statements)

References 34 publications

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“…Under regeneration by aeration, only a small amount of Cu(NH 3 ) 4 2+ is consumed; thus, it is regarded as the catalyst [45]. However, in the presence of excessive oxidizer in the solution, thiosulfate decomposition is then enhanced to form the breakdown product, such as tetrathionate, as indicated by Equation (7).…”

Section: Leaching Experimentsmentioning

confidence: 99%

“…Alternatively, numerous studies have been devoted to exploring potentially greener chemicals to extract gold from primary and secondary resources. These developed methods include leaching by different types of acids [7,8], thiourea [9], glycine [10,11], and thiosulfate [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…Materials 2023, 16, x FOR PEER REVIEW 2 of 29 to exploring potentially greener chemicals to extract gold from primary and secondary resources. These developed methods include leaching by different types of acids [7,8], thiourea [9], glycine [10,11], and thiosulfate [12][13][14][15]. Among the above-mentioned alternatives, thiosulfate leaching has been proven to be an efficient, economic, and greener method to recover Au [16].…”

Section: Introductionmentioning

confidence: 99%

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Investigation of the Bimodal Leaching Response of RAM Chip Gold Fingers in Ammonia Thiosulfate Solution

2023

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Oxidative thiosulfate leaching using Cu(II)-NH3 has been explored for both mining and recycling applications as a promising method for Au extraction. This study seeks to understand the dissolution behavior of Au from waste RAM chips using a Cu(II)-NH3-S2O3 solution. In the course of this work, bimodal leaching and Au loss were observed in a manner that we have not identified in the literature. Identification of the existence of a specific Au-Ni-Cu lamellar structure in the gold fingers from RAM chips by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS) revealed the possibility of interference between Au recovery and the existence of Cu and Ni. During leaching, the co-extraction of Ni was found to predict a negative impact on the Au recovery, as a result of chemical interactions from the Au-Ni-Cu interlayer. Decopperization as a pretreatment was found necessary to remove the pre-existing Cu and promote Au leaching. As part of the study parameters, such as Cu(II) concentration, aeration rates, thiosulfate and ammonia concentrations, particle sizes, and temperatures, were investigated. A satisfactory Au recovery of 98% was achieved using 50 mM Cu(II), 120 mL/min aeration rate, 0.5 M (NH3)2S2O3, and 0.75 M NH4OH (i.e., AT/AH ratio of 0.67) for 4 h residence time at room temperature (25 °C). However, there were several high recoveries prior to Au loss from the lixiviant. It was revealed that the main cause of lower Au recovery was due to a precipitation or cementation reaction that included a sulfur species formation. Because of the bimodal leaching, a composite response comprised of the time to Au loss and maximum recovery was developed, termed leaching proclivity, to facilitate statistical analysis. Furthermore, this study explores the interactions between Au-Ni-Cu and provides suggestions for improving Au thiosulfate leaching under the interference of co-existing metals from waste PCB materials.

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Section: Leaching Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of the Bimodal Leaching Response of RAM Chip Gold Fingers in Ammonia Thiosulfate Solution

2023

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“…In hydrometallurgy, chloride solutions can be used for the leaching of both primary and secondary metal-containing raw materials. − In particular, leaching gold with copper chloride has been studied , as a less toxic alternative to traditional cyanide leaching. Since gold and copper are often found together in ores in varying ratios, the capability of chloride to effectively leach copper ores increases the utilization potential of this method on industrial scale. , Due to the variation in raw material, the gold concentration may often be too low for its viable recovery.…”

Section: Introductionmentioning

confidence: 99%

Recovery of Gold as Nanoparticles from Gold-Poor Au-Cu-Cl Solutions

et al. 2023

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Electrochemical methods for preparing functional surfaces typically use optimized solutions where competing reactions do not need to be considered. However, with the increased demand for resource efficiency, selective deposition methods that can make use of more complex solutions are gaining importance. In this study, we show how gold recovery as nanoparticles from Au-Cu-Cl solutions can be assisted by electrochemically generated Cu 1+ species. In the electrochemically assisted reduction (EAR) method, a low-energy electrochemical step is employed, followed by spontaneous gold reduction onto the electrode. The studied solutions mimic challenging hydrometallurgical process solutions where the ratio of gold (5 ppm) to copper (20 g/L) is low. In addition to selective gold recovery, by controlling the electrochemical pulse parameters, the loss of deposits due to corrosion could be minimized, current efficiency improved from ∼0 to >10%, and relatively narrow particle size distributions achieved (43 ± 10 nm), and this can be done even at a high (4.5 M) NaCl concentration.

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“…Various options for pyro-and hydrometallurgical processing of refractory gold-bearing concentrates have been proposed: roasting at a relatively low temperature [1] and twostage fi ring in a fl uidized bed furnace [2,3], direct reduction smelting [4], pretreatment of concentrates using microwave pyrolysis [5,6], direct [7] and combined methods of leaching [8,9]. Some of them allow complex processing of mineral raw materials, but require multi-stage processing, expensive equipment and reagents.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the process of sulfiding of gold-arsenic containing ores and concentrates

Mambetalieva¹,

Mamyrbayeva²,

Turysbekov³

et al. 2022

Nauk. visn. nat. hirn. univ.

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Purpose. Research of the removal of arsenic by sulfiding from gold-arsenic containing concentrates of the Bakyrchik deposit. Methodology. To determine the composition of the samples, chemical and electron probe analysis were carried out; to determine the phase composition of materials, X-ray analysis was conducted. In order to predict the process of sulfidation of arsenic and its compounds in the range of 2982000 K, a thermodynamic analysis was performed. To establish the optimal conditions for the process of sulfiding arsenic and its compounds, studies were carried out to determine the effect of temperature and the consumption of elemental sulfur on the degree of sublimation of arsenic from gold-arsenic concentrate. The sulfiding roasting of the concentrate was carried out with elemental sulfur vapor coming from a new design evaporator with a mixture of gaseous nitrogen. Findings. The main minerals of the original concentrate are pyrite, marcasite, arsenopyrite, native gold and silver. Significant elements in the concentrate are, %: arsenic 2.93.1, iron 707.3, gold 40. It has been calculated by thermodynamic analysis that when the main minerals of gold-arsenic containing refractory ores and concentrates interact with sulfur in a neutral environment and in the range of 5001000 C, reactions of formation and removal of arsenic in the form of sulfides As2S3 and As4S4 occur. When a new design evaporator supplies elemental sulfur in a mixture with neutral gas and with an increase in firing temperature from 700 to 850 C at S : As = 0.35 : 1, the degree of sublimation of arsenic increases from 94.7 to 98.2%, with FeS2 : As = 1.3:1 from 94.0 to 99.5%. With an increase in the consumption of elemental sulfur vapor (with an increase in the S : As ratio from 0.35:1 to 0.6 : 1 and a temperature from 700 to 800 C), the degree of sublimation of arsenic from the gold-arsenic product reaches up to 99%. The condensed sublimes contained up to 98.599% As4S4 and As2S3, the dust caught in cyclones is close in its composition to the composition of cinder. Originality. A new technology for the removal of arsenic from gold-arsenic containing concentrates in an oxygen-free atmosphere in the temperature range of 700850 C with the removal and capture of arsenic sulfides up to 100% is proposed. The regularity of the degree of sulfidation of arsenic and its oxidized compounds by elemental sulfur vapors in a mixture with a neutral gas to As4S4 and As2S3 has been established. Practical value. The use of the new technology makes it possible to completely convert arsenic into sulfide forms which are environmentally friendly, convenient for storage, burial, or for use as antiseptics. The development can be used for processing arsenic-containing polymetallic ore materials.

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Direct Cupric Chloride Leaching of Gold from Refractory Sulfide Ore: Process Simulation and Life Cycle Assessment

Cited by 14 publications

References 34 publications

Investigation of the Bimodal Leaching Response of RAM Chip Gold Fingers in Ammonia Thiosulfate Solution

Investigation of the Bimodal Leaching Response of RAM Chip Gold Fingers in Ammonia Thiosulfate Solution

Recovery of Gold as Nanoparticles from Gold-Poor Au-Cu-Cl Solutions

Investigation of the process of sulfiding of gold-arsenic containing ores and concentrates

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