process leaching thiosulfate
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- process leaching thiosulfate
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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Oxidized copper minerals, as well as chalcocite and bornite, dissolve in cyanide solutions, and in many cases, recovery of gold from fouled solutions becomes very difficult, if not impossible. Thiosulfate leaching of gold and silver has been known since 1858. In the Patera process, which was used for silver recovery for many years (Lidell …
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Moreover, the process of gold dissolution in copper–tartrate–thiosulfate solution can be divided into two stages, as shown in Fig. 1. In the first stage, the dissolved gold dramatically increases in the initial 1 h of leaching and then slightly increases with extended time in the second stage.
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Thiosulfate leaching was first proposed as a part of Von Patera process, where the leaching was implemented after chloridizing …
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The effects of various parameters on the process, such as leaching time (1–4 h), ammonium thiosulfate concentration (0.05–0.5 M), copper sulfate (CuSO 4 ), concentration (0.05–0.25 M), solid to liquid …
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mixtures. Types of separation process that is appropriate for gold processing is leaching process. Leaching is a process of extracting a soluble constituent from a solid by means of solvent [1]. Leaching processes also are used extensively in the metals processing industries and is a main stage of reactant in gold production [2].
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Alkaline sulfur-containing lixiviants, including thiosulfate, polysulfides, and alkaline sulfide solutions, stand out as a promising class of alternatives to cyanide because of their low toxicity, high efficiency, and strong adaptability. In this paper, we summarized the research progress and remaining challenges in gold extraction using these noncyanide …
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With cyanidation, a gold recovery of 80.6 % was accomplished at 24 hours, whereas with ammoniacal thiosulfate leaching process a 80.9 % of gold recovery was achieved at just one hour of …
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Thiosulfate leaching was first proposed as a part of Von Patera process, where the leaching was implemented after chloridizing roasting. In the initial stage of thiosulfate leaching, high temperature and pressure were required until an improvement was carried out by using ammoniacal thiosulfate solution to leach copper-bearing …
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1. Introduction. Currently, cyanide is the predominant lixiviant used to extract gold due to its strong complexation with gold and the technical simplicity of the leaching process (Avraamides, 1982, Habashi, 1987, Marsden and House, 2006).However, the use of cyanide can bring challenges in terms of environmental, health and safety aspects …
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Nov 13, 2011. #6. Wyndham. If you roast the sand,then grind the sand in a ball mill, or rod mill with citric acid,it gets rid of iron and sulfides. Rinse the sand well with water and you are good to go. It is always a good idea to eliminate all the junk you can, before leaching. Q.
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addition, the Leaching Team analyzed the thiosulfate leaching process compared to the traditional cyanide process. They found that the profit of the thiosulfate leaching process was similar to that of the traditional cyanide method. Furthermore, it was found that after three hours of thiosulfate leaching, 63 weight% of gold was recovered of the ...
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In order to determine the effect of the applied current on the silver recovery, the SEE process was examined using a leaching solution containing 123 mg of silver powder, 0.2 M thiosulfate at pH 10.2 (adjusted with ammonia) and applying a constant current of 8, 12, 24 and 36 mA during 4 h.
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The leachate produced by thiosulfate leaching of pyrolyzed PCBs was decided to bypass solvent extraction and directly apply to the precipitation process. 3.4 Precipitation In this study, three different oxidants (hydrogen peroxide, hypochlorous acid and perchloric acid) were used to decompose the gold thiosulfate complex, Au(S 2 O 3 …
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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 …
به خواندن ادامه دهیدThe results show that thiosulfate is the only effective complexing agent with aurous ions, while tartrate works as a copper ligand. The process of gold dissolution in …
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In this review, the basic theory and process development of some main gold leaching systems based on thiosulfate solutions were systematically summarized to illustrate the research status on thiosulfate leaching process.
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Thiosulfate leaching is a process that recovers gold from ore without the use of cyanide. Jacob Jason Demedici developed the thiosulfate leaching process because in some jurisdictions, increased ...
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The effect of ultrasound on gold leaching rate and kinetics was investigated in the Co-NH 3-S 2 O 3 2− system. First, the effects of ultrasound power, temperature, the concentration of thiosulfate, cobalt and ammonia on gold leaching rate were studied under ultrasound.The optimized leaching parameters are 0.03 M Co 2+, 0.2 M S 2 O 3 2−, 1 M …
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Leaching process. The process of releasing solid material constituents into a contacting fluid phase is known as leaching. It is indifferent to all constituents—such as major and minor matrix components, as well as inorganic, organic, and radionuclide contaminant. ... Thiosulfate leaching. Thiosulfate solutions can be used as an …
به خواندن ادامه دهیدUsing the same experimental conditions but using residues obtained following an oxidative leaching process, it was reported that 45% gold dissolution was obtained with a particle size < 3 mm and 90% copper removed. ... Pandey BD (2014) Optimizing the thiosulfate leaching of gold from printed circuit boards of discarded …
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The leaching of thiosulfate requires oxidant to speed up the leaching process, which results in high consumption of thiosulfate. Copper is one of the most …
به خواندن ادامه دهیدAbstract: Gold leaching is an important process to extract gold from ore. Conventional alkaline cyanide process and alternative nontoxic lixiviants including thiosulfate, thiourea, thiocyanate, and halogen have been widely investigated. However, density functional theory (DFT) study on the gold complexes Au(CN)2, Au(S 2O3)2 3, …
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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 via oxidation of iron(II) …
به خواندن ادامه دهیدA process of biooxidation followed by thiosulfate leaching of gold from refractory gold concentrate was investigated. Mineralogical studies on the concentrate …
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Thiosulfate leaching can be considered a non-toxic process, the gold dissolution rates can be faster than conventional cyanidation and, due to the decreased interference of foreign cations, high ...
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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 replace resins in the gold recovery process, improve efficiency, and reduce operating cost.
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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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Thiosulfate leaching can be considered a non-toxic process, the gold dissolution rates can be faster than conventional cyanidation and, due to the decreased …
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Therefore, the co-intensifying leaching systems, such as thiourea-thiocyanate, thiourea-thiosulfate, and thiourea-microbial leaching, deserve further investigation. (5) Although the sulfur-containing leaching agent is non-toxic or slightly toxic, the wastewater produced in the process cannot be directly discharged.
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The use of activated carbon as catalyst in the thiosulfate leach of gold is a process alternative that may not require the addition of surrogate oxidants (like copper), can work at temperatures as low as 30 °C, and thiosulfate degradations of 2.1 kg per ton of ore or lower, making it an attractive alternative for the leaching of gold.
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Gold Leaching by Thiosulfate and Glycine from Mineral. ... This dissolution process is favored by increasing the concentration of thiosulfate from 5 g/L to 20 g/L. It has been observed that of the gold present in the sample can be recovered when 20 g/L thiosulfate is used. By varying the solid–liquid ratios from 1:2 to 1:3, a process of ...
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The leaching behaviors of gold and silver from a complex sulfide concentrate in copper-tartrate-thiosulfate solutions were investigated in this paper. Experimental parameters, including temperature, initial pulp pH, and concentration of copper, tartrate, and thiosulfate, were systematically studied. The copper-tartrate-thiosulfate leaching …
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cyanide, thiosulfate leaching is an alkaline process operated in the pH range 8 to 10 with the addition of ammonia 16 . Copper, as Cu(II), is used as oxidant for it is a good coordinator for gold ...
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The Metallurgy and Materials Society of the Canadian Institute for Mining recently feted Barrick with the c Innovation Award for successfully developing a thiosulfate leaching circuit at its Goldstrike mine in Nevada. The new circuit uses thiosulfate, a chemical reagent, to treat double-refractory ore that cannot be treated …
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Thiosulfate leaching-resin adsorption recovery, an environmentally friendly process, has been developed to efficiently extract gold from an oxide gold concentrate. 80.5% of gold extraction could be achieved by thiosulfate leaching under the conditions of (NH 4) 2 S 2 O 3 0.2 mol/L, CuSO 4 0.025 mol/L, NH 3 1.5 mol/L and leaching time 8 h, …
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In this study, thiosulphate leaching combined with ultra-fine grinding (UFG) was studied for silver extraction from an arsenical refractory ore. Direct cyanidation of the ore (d80: 50 µm) led to a low silver extraction of ≤ 70% over 24 h. leaching period. Extraction of silver in cyanide leaching was improved to 85% after ultra-fine grinding.
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Schematic comparison of the thiosulfate (a) and polysulfide (b) mechanisms in the (bio)leaching of metal sulfides (from Schippers and Sand 1999, modified).Iron(III) ions attack metal sulfides (MS) by electron extraction and are thereby reduced to the iron(II) ion form.As a result, the metal sulfide crystal releases metal cations (M 2+) and water …
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