— The acid-insoluble metal sulfides FeS 2, MoS2, and WS2 are chemically attacked by iron(III) hexahydrate ions, generating thiosulfate, which is oxidized to sulfuric acid, explaining leaching of metal sulfide by Thiobacillus thiooxidans. ABSTRACT The acid-insoluble metal sulfides FeS2, MoS2, and WS2 are chemically attacked by iron(III) …
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— The reason for this is uncertain. It can be seen from Figures 11 and 12 that the effect of pH on the copper-thiosulfate reaction is more dramatic than the effect on the gold leaching reaction. Hence thiosulfate leaching should be carried out at pH values above I 1.4 to minimise the consumption ofthiosulfate. 1080 P.L. Breuer and M. 1.
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— @article{osti_318833, title = {Bacterial leaching of metal sulfides proceeds by two indirect mechanisms via thiosulfate or via polysulfides and sulfur}, author = {Schippers, A and Sand, W}, abstractNote = {Bacterial leaching, the biooxidation of metal sulfides to soluble metal sulfates and sulfuric acid, is effected by specialized bacteria.
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Metals. The use of thiosulfate to extract gold from refractory ores is promising because of its non-toxicity and high selectivity. Sulfide minerals (i.e., pyrite, arsenopyrite, chalcopyrite), major gold carriers in refractory gold ores, however, hinder gold extraction due to the high consumption of a lixiviant.
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— Thiosulfate leaching combined with ion-exchange resins is an innovative alternative for gold recovery. According to the properties of activated carbon, it could …
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— This literature review provides an update of ammoniacal thiosulfate as a potential lixiviant of gold, the history of thiosulfate leaching and recent progress on thiosulfate leaching of gold, as well as the production, oxidation, and stabilization of thiosulfate. The leaching results of different types of gold ores including oxide, sulfide ...
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Learn about the diverse applications and impacts of microbial research in this peer-reviewed journal of ASM.
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thiosulfate gold from black sand. Dealing with Black Sands: getting all the gold out of, Information on how to capture all fine Gold from your black sands: Dea
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— Thiosulfate is a divalent type 'A' soft ligand, which tends to form more stable complexes with low-spin d 8 {Pd II, Pt II, Au III} and d 10 {Cu I, Ag I, Au I, Hg II} metal ions Livingstone, 1965, Wilkinson, 1987monly, the thiosulfate ion acts as a unidentate ligand via the terminal sulfur atom, establishing strong σ-bonds with a metal ion which …
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— Here, it was found that SDD can achieve the purpose of gold ion enrichment by forming granular precipitations with Au(I) in the thiosulfate leaching solution and the recycling of thiosulfate and …
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— I expect Iron content will have a profound effect on a thiosulfate leach. When thiosulfate is used for dissolving silver chloride encrusted karat gold, it is then cemented …
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— Table 1 shows the initial gold leach rate (0–10 min) and the gold leach rate between 5 and 7 h for each of the experiments. For comparison, the oxygen diffusion limiting rate for gold leaching in air saturated cyanide solutions at 300 rpm is 55 μmol/m 2 s (Jeffrey and Ritchie, 2000).For each of the leaching systems, it can be seen from both …
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— In this study, an environmental friendly effective process was developed, which consisted of oxidation pretreatment, thiosulfate leaching and electrodeposition for silver recovery from anode slime and was proposed in the flow chat in Fig. 1.In the step of oxidation pretreatment, MnO 2 was used to treat anode slime in dilute sulphuric acid. As …
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— Under optimized experimental conditions of initial pH 8.50, molar ratio of copper to thiosulfate 0.1 and leaching temperature 313 K, the mercury leaching rate is 92.37% after 7-h leaching. The study on the leaching mechanism indicates that Cu + can be substituted by Hg 2+ to form soluble Hg(S 2 O 3 ) n 2−2n in solution and Cu 2 S …
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— Gold leaching is the key stage in process of gold mining. There are a few well-reputed leaching methods using a variety of different reagents. Nowadays the most …
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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 dissolved gold.
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— Abstract Bioleaching of metal sulfides is performed by diverse microorganisms. The dissolution of metal sulfides occurs via two chemical pathways, either the thiosulfate or the polysulfide pathway. These are determined by the metal sulfides' mineralogy and their acid solubility. The microbial cell enables metal sulfide dissolution …
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— The ammoniacal thiosulfate leaching process for gold and silver extraction has been reviewed in terms of leaching mechanism, thermodynamics, thiosulfate …
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— Ammoniacal thiosulfate has been studied over the last three decades as a nontoxic and highly-efficient alternative lixiviant to cyanide for leaching gold from gold ores with copper(II) acting as a catalyst [1,2].Much of the work has concentrated on copper-gold ores, carbonaceous gold ores and complex sulfidic gold ores where the recovery of gold …
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— If "your black sand" does not contain silver, only gold will react and will later be precipitated. Of course, you can act on it before with an acid, or acid/peroxide if …
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— Would Sodium Thiosulfate leach be safer faster and eazier . Reply. B. Blacktoadd Active member. Joined Jul 14, 2008 ... Type in Gold from black sand and you will find lots of articles on getting it. I was also told, black sand and Iron is always found around gold, but gold is not always found around black sand. Heating up the sand in hot …
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— Precious metals recovery from secondary sources is a novel alternative since they hold higher contents of several metals than average ores. In this research gold and silver were recovered from Waste Printed Circuit Boards (WPCBs) with the use of ammonia-thiosulfate solutions and the MTA 5011 ion exchange resin.
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— A review is presented summarising the leaching of gold with ammoniacal thiosulfate solutions, and evaluating the current use and development of ion exchange resins for the recovery of gold and ...
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— The gold in the concentrate calcine was leached with three leaching methods, including thiosulfate leaching, thiourea leaching, and thiourea and thiosulfate leaching. The leaching conditions of gold by thiosulfate were as follows: 5 mmol/L CuSO 4, 0.6 mol/L NH 3, 0.1 mol/L Na 2 S 2 O 3, and leaching time of 12 h [26], and gold …
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— The thiosulfate leaching reduces the load onto environment since the chemical reagents used in this process are already used in agriculture. As shown in the literature (Smolyaninov et al. 2012), the gold-thiosulfate complex is eluted by polithionates that are produced with the use of iodine, bromine, and hydrogen peroxide as oxidants. …
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Thiosulfate is a lixiviant with potential applications for extraction of precious metals with lower environmental impact. As an alternative leaching reagent to cyanide, thiosulfate has promising gold extraction efficiency with much lower risk to operators and the environment. Thiosulfate is often produced at high temperatures via processes utilizing sulfide or …
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— Screening, purification, and identification of deep-sea bacteria possessing potential thiosulfate oxidation capability. During the course of screening of deep-sea bacteria possessing potential ...
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that gold recovery is difficult by thiosulfate leaching without any pre-treatment, and the recovery of gold only is 10.1%. After roasting and oxidizing, the gold leaching rate increases substantially. The leaching rate of gold reaches 71.2% with the optimal leaching technological parameters (Li et al.,
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— Thiosulfate is an excellant method of leaching salts of metals. Sodium Thiosulfate will leach all of the salts of silver and gold and leave a colorless solution. ... Please can you tell me more about how to use the sodium or ammonium thiosulfate for placer gold in (black) sand? Reply. L. Lino1406 Well-known member. Joined Nov 1, …
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AXEL SCHIPPERS* AND WOLFGANG SAND Abteilung Mikrobiologie, Institut fu¨r Allgemeine Botanik, Universita¨t Hamburg, ... (III) ion-mediated leaching mechanism via thiosulfate and polythionates (18 ...
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Contribute to dinglei2022/en development by creating an account on GitHub.
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— Thiosulfate is an alternative lixiviant for the leaching of precious metals. Research and development of thiosulfate leach technology has been prompted by environmental concerns with the use of ...
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— Ion-exchange resin adsorption has been found to be most suitable to recover gold from the thiosulfate leach solutions (Jeffrey et al., 2010, Xu et al., 2017).This is mainly due to that resins can be used in the form of resin-in-pulp (RIP) or resin-in-leach (RIL), and the gold desorption from resins and the regeneration of resins can be achieved …
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— The thiosulphate leaching proved to be a very promising, environmental-friendly alternative to cyanide leaching for Au and Ag recovery [20]. Usually it is used …
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— Thiosulfate offers a nontoxic alternative to cyanide for processing gold ores. The mechanism of leaching gold using ammoniacal thiosulfate solution is driven by the Cu(II)-Cu(I) redox couple and is complicated by competing ligands such as NH3 and S2O32−. It is shown that an understanding of the copper speciation and sulfur …
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