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Thiosulfate as one of the most promising reagent thiosulfate according to literature revealed an insufficient leaching behavior. The gold dissolution was hindered …
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The cyanidation process is affected by a number of influential parameters, such as the availability of oxygen at the solid–liquid interface, the pH and Eh of the solid–solvent suspension, the presence of ions …
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Prior to the inception of cyanide, chlorine was extensively used as a leaching reagent for gold recovery from calcines, ores and concentrates. Chlorine can be generated in slurries and solutions via electrolysis of NaCl solution or by addition of MnO 2. Conclusions. This paper has reviewed the most promising alternative gold leaching …
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Mercury amalgamation is the method of choice to recover gold in artisanal and small-scale gold mining (ASGM). However, despite the low cost and simplicity of this method, the use of mercury presents serious health and environmental risks, as well as low efficiency in gold extraction. This study investigates the application of cyanide and …
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Commendable effort keep it up!! Thiosulfate is one of alternative reagents to cyanide; many plants still uses cyanide as the primary reagent for gold leaching even though its side effects to environment are well known. While thiosulfate is a potential option, you do need to look at the mineralogy of the deposit.
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Thiosulfate leaching is a promising alternative to cyanidation, and the main hindrances for its wide commercial …
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Thiourea. Thiosulphate. Thiocyanate. 1. Introduction. The debate surrounding the use of cyanide in the mining industry has fuelled considerable investigation into the …
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In the case of leaching sulfide ore thiosulphate leaching required only 1 hour to achieve 90% gold recovery whereas cyanidation required at least 24 hours to extract 50% of the gold. 5.1 Factors ...
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Cyanide-free mild chloride leaching was investigated. •. Gold could be recovered even at <520 mV vs. Ag/AgCl in carbon-in-chloride-leach mode. •. Copper was a stronger oxidant than iron in gold leaching. •. Gold was oxidized by in-situ dissolving impurities. •. Seawater contains enough chlorides to dissolve gold.
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Furthermore, ammonia leaching as a pretreatment process ahead of cyanide leaching was also examined. Only ~12% of gold was extracted by direct cyanide leaching of the ore. The addition of lead nitrate did not affect the leaching of gold. When ammoniacal cyanide leaching system was used, the extraction of gold was significantly improved to >90%.
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The thiosulphate leaching process, followed by resin-in-pulp gold extraction, has been developed by SGS to the point where it is a technically and economically viable …
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Abstract. This paper reviews a series of alternative lixiviant systems for the recovery of gold from ores and concentrates. For over 100 years, cyanide has been the leach reagent of choice in gold ...
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concerns, cyanide leaching has been banned in many regions at present. Furthermore, the leaching period of cyanidation is usually as long as 24 h [3] and gold cannot be effectively leached from refractory gold ores. Thus, alternative lixiviants for gold have received more and more attention in recent years.
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In total, 27 possible solvents have been investigated as alternatives to cyanide for leaching gold. These can be grouped into 11 categories as outlined in Table 27.1. Table 27.1. ... 2–6 h O 2 at 700 kPa) achieved gold extractions of the order of 90–96% compared with direct cyanidation where gold extraction was less than 20% ...
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A process of biooxidation followed by thiosulfate leaching of gold from refractory gold concentrate was investigated. Mineralogical studies on the concentrate showed that very fine gold grains (<10 µm) were encapsulated in pyrite and arsenopyrite, while the proportion of monomer gold was only 21%. The gold-bearing sample was …
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But there are alternatives to cyanide that are being developed by companies that are working with gold mining companies to commercialize their technologies. Raponi says the most advanced …
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Thiosulphate is an attractive alternative reagent to cyanide for processing gold ores. It is relatively cheap and non-toxic, forms relatively strong gold and silver …
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Cyanide gold leaching is generally conducted at pH over 10, and hence acidic slurries of oxidation processes are typically followed by neutralization steps prior to gold cyanidation. This often leads to a complex process circuit (such as the Pueblo Viejo operation of Barrick Gold Corp.), large lime consumption, and large volumes of gypsum …
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The substitutes for cyanide can be classified as traditional and novel non-cyanide gold leaching reagents. The traditional alternatives mainly include thiourea, halide, polysulfide, thiocyanate, lime sulfur synthetic solution (LSSS), and thiosulfate (Hilson and Monhemius, 2006, Sun et al., 2020, Xing et al., 2019).Although considerable …
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Thiosulphate is an attractive alternative reagent to cyanide for processing gold ores. It is relatively cheap and non-toxic, forms relatively strong gold and silver complexes, and readily leaches gold ores in ammoniacal solutions, catalysed by Cu(II). It is particularly suited to carbonaceous ores where the recovery of gold by cyanide is poor.
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Thiosulfate is generally considered to be an attractive alternative reagent to cyanide for processing gold. It is relatively inexpensive and nontoxic, forms strong gold …
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Since the birth of cyanidation, it has been dominant in the gold extraction industry. Recently, with the increasing awareness of environmental hazards and potential risks posed by the severe toxicity of cyanide, attempts to seek alternative lixiviants have arisen. ... An alternative to cyanide leaching of waste activated carbon ash for gold …
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Cyanidation using biologically produced cyanide may be considered as an appropriate alternative to conventional cyanidation. This technique usually is referred to as alkaline or heterotrophic bioleaching. ... Cyanide-free thiosulphate gold leaching has been researched extensively and applied on an industrial scale since late 2014. Both ...
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Recent Advances in the Development of an Alternative to the Cyanidation Process. Subject. A process based on thiusulphate leaching, followed by resin-in-pulp gold …
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Thiosulfate leaching is a promising alternative to cyanidation, and the main hindrances for its wide commercial application are the high thiosulfate consumption and the difficult recovery of ...
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Thiosulfate is considered a non-toxic alternative to cyanide and can leach gold faster than cyanide. In the conventional cyanide process, the recovery of gold and silver from ores is hindered by a variety of metal impurities like copper, arsenic, antimony, zinc and nickel, since these consume either cyanide or oxygen.
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Abstract. The ammoniacal thiosulfate leaching process for gold and silver extraction has been reviewed in terms of leaching mechanism, thermodynamics, thiosulfate stability, and gold recovery options. The application to different ore types and process options have also been discussed. The thiosulfate leaching process it catalysed by …
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The average gold extracted between the surface tailings and 1m deep tailings within just 5 h reaction time is 73.9 % for thiosulfate leaching and 73.4 % for cyanide leaching. Considering that ...
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Although the usage of cyanide is considered an environmental problem, gold leaching is where most cyanide is used. Water used in gold elution is approximately 10% of the volume in cyanidation, and it is recycled up to . Likewise, it is important to remark that using thiosulfate instead of cyanide in the gold leaching step would …
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Thiosulphate as an alternative to cyanide for gold processing – issues and impediments. D. Muir M. Aylmore. Materials Science. 2004. Abstract Thiosulphate is an attractive alternative reagent to cyanide for processing gold ores. It is relatively cheap and non-toxic, forms relatively strong gold and silver complexes, and readily….
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