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This study presents the novel idea of a cyanide-free leaching method, i.e., glycine-ammonia leaching in the presence of permanganate, to treat a low-grade and copper-bearing gold tailing. Ammonia played a key role as a pH modifier, lixiviant and potential catalyst (as cupric ammine) in this study. Replacing ammonia with other pH …
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Gold extraction has long relied on cyanidation yet faces challenges including toxicity and refractory ore usage. This study explores the glycine-copper-cyanide leaching system's potential for gold recovery from sedimentary rock-hosted disseminated Agh-Darreh gold ore. Initially, cyanidation experiments tested increasing temperatures' …
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Thiourea leaching of gold from waste electronics has been extensively studied and shows good potential for industrial application. However, most of the research that considered gold leaching using thiourea focuses predominantly on the leaching steps, but the following recovery stages remain elusive.
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Pressure oxidation conditions are similar to those used in conventional refractory gold autoclaves. Atmospheric leaching of POX residue is one patented Kell innovation that is useful for ore types with other HCl-soluble components, while the heat treatment innovation is useful for ore types with components deleterious to chlorination …
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A fundamental study of the alkaline sulfide leaching of gold M.I. Jeffrey1* and C.G Anderson2 1 Department of Chemical Engineering, Monash University, Vic., 3800, Australia ... 2 gas and the increasing concerns over emissions, many gold mines have considered other technologies such as bacterial leaching and pressure oxidation for treating sulfide
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In the second step, insolubles from the first step underwent a second acid leaching with 2 M H 2 SO 4, an S:L ratio of 1:1.5, 120 RPM agitation, and a 7-day leaching time, resulting in recoveries of 12.5 ppm silver and 0.5 ppm gold for H 2 SO 4, and 1 ppm gold for HNO 3.
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Cyanide leaching of gold catalysts can remove less active gold. • Gold thrifting is thereby enabled for the chosen system investigated. • Cyanide leaching may be selective and may help in gold speciation studies. • Cyanide leaching leads to a modification of gold oxidation state.
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The gold content obtained from the aqua regia leaching process was measured by Inductively Coupled Plasma—Optical Emission Spectrometer (ICP-OES) (Agilent, 5100). Finally, the extraction yield of gold from the aqua regia process was investigated and further set as a reference value to estimate the gold yield obtained …
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The objective of this study was to investigate thiourea leaching of gold present in the uranium tailings. Sulfuric acid treatment for raw material is important in order to dissolve uranium as well as to remove easily leachable metals. The acidic thiourea solution was proposed as a non-toxic possible alternative process route to cyanide in …
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This study investigated the effects of arsenopyrite oxidation on gold dissolution in a copper(II) (Cu 2+)–ethylenediamine (en)–S 2 O 3 2− gold-leaching system. During gold leaching, arsenopyrite oxidation considerably influences the properties of the leaching system, thereby increasing the rate of gold dissolution.
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Cyanide is a lixiviant, or reagent that is used to leach, often in tanks, gold from a solid matrix and form a gold cyanide complex. The gold cyanide complex is then extracted from the pulp or slurry by adsorption onto activated carbon. CIL stands for carbon-in-leach. This is a gold extraction process called cyanidation where ... Gold …
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The Philippines has the world's third largest known Au deposits and is ranked 20th in global gold production. Of the country's annual production, about 80% is from the small-scale gold mining (SSGM) sector. This work estimates the first location-specific life cycle energy use and CO2 emissions of SSGM establishments in the …
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The consumption of cyanide during processing operations is a major economic cost in the extraction of gold from its ores, while the discharge of cyanide wastes may result in significant environmental pollution. Many factors influence the levels of consumption and discharge of cyanide, including ore mineralogy and lixiviant solution …
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Leaching, often gold, is the process of extracting a soluble constituent from a solid by means of a solvent. In extractive metallurgy, of gold, it is the process of dissolving a certain mineral (or minerals) from an ore or a concentrate, or dissolving certain constituents from materials such as a calcines, mattes, scrap alloys, anodic slimes, etc., …
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Distinct advantages have been reported for bio-leaching of gold over traditional physicochemical methods. ... The cyanidation method of extraction also gives rise to the emission of hydrogen cyanide, global warming and production of huge amounts of tailings a potential source of HM due to the extraction of low-grade ores .
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• Available data suggest bioleaching and biooxidation processes reduce carbon emissions. ... Scale up of this combined process has demonstrated sustained reduction in cyanide consumption in the gold leaching circuit downstream after neutralization and thickening. A commercial-scale MesoTHERM circuit has been running …
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In the past 25 years there has been a wide expansion of the use of cyanide heap leaching by the mining industry. This process allows profitable recovery of gold and silver from low-grade ore. Heap leach pads are constructed on slight drainage grades and lined with an impervious clay and/or geotextile.
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Alternative methods for gold leaching require much effort to scale up applications. ... and low gas emission. However, it is still challenging to develop a complete technology for widespread application due to the complexity of e-waste and very low content of gold. Conventional leaching of gold may not satisfy environmental …
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The application of pressure oxidation (POX) followed by thiosulfate gold leaching is an efficient method used to extract gold from double refractory gold ores containing both sulfide and carbonaceous matter. This process is expected to result in high gold recovery rates, as it liberates gold from sulfides and eliminates the preg-robbing …
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