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gold leaching using ammonium thiosulfate

Gold Leaching by Using Ammonium Thiosulfate Solution

The sponge gold (99.92 % pure) has been leached with ammonium thiosulfate solution. In this investigation, the gold leaching rate (extraction rate) and the thiosulfate oxidation rate (consumption rate) have been studied on the effects of CuSO 4, (NH 4) 2 S 2 O 3, (NH 4) 2 SO 4, NH 4 OH, stirring speed and retention time. The copper ion acts as a catalyst in gold dissolution, on the other hand ...

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Ammonium thiosulfate extraction of gold from printed ...

01-01-2020  The ammonium thiosulfate solution used for the leaching experiments with time or with and without O 2 was composed of 1 M Na 2 S 2 O 3 5H 2 O, 0.5 M NH 4 OH, 0.25 M (NH 4) 2 SO 4 and 10 mM CuSO 4 5H 2 O. Prior to the leaching experiments without oxygen, dissolved O 2 was removed by purging 10 ml of ammonium thiosulfate solution for 30 min with N 2 (>99.99%).

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Ammoniacal thiosulphate leaching of gold ore

Ammoniacal thiosulphate leaching of gold finds a better substitute as it is non-toxic and environmentally safe as compared to the toxic cyanide system for gold extraction. In the present study, an attempt is made to assess the feasibility of ammoniacal thiosulphate leaching of gold

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THE STUDY OF THE KINETICS OF GOLD LEACHING IN THE

The gold leaching rate in ammonium thiosulfate in the presence of copper species is mainly controlled by the cathodic process, which is under diffusion or mixed kinetics control. The results of the rotating gold disk leaching study are consistent with those from the electrochemical study. The gold leaching process in ammonium

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THIOSULPHATE LEACHING – AN ALTERNATIVE TO CYANIDATION

Thiosulphate leaching is a process that removes gold from gold bearing ores without the use of cyanide. Although not as aggressive a leaching agent as cyanide, thiosulphate offers several technological advantages including its lower toxicity and greater efficiency with gold deposits associated with preg-robbing ores. The thiosulphate leaching process, followed

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The treatment of copper–gold ores by ammonium

01-10-2002  In conclusion, ammonium thiosulfate leaching for gold recovery preferably should be performed at: • low thiosulfate concentrations, ranging from 0.1 to 0.2 M; • an ammonia to thiosulfate ratio of 1–2; • copper concentrations ranging from 50 to 100 ppm; • an alkaline pH, preferably 9–10; • ambient temperature to 50 °C. 2.3.

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US6632264B2 - Gold recovery from thiosulfate leaching ...

FIG. 1 is a flow sheet illustrating a process for recovering gold from ammonium thiosulfate (ATS) leach solutions using resin-in-pulp (RIP). FIG. 2 is a flow sheet showing an alternative process for recovering gold from ammonium thiosulfate (ATS) leach solutions using a resin column.

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Improvement of thiosulfate stability in gold leaching ...

01-05-2003  Ammonium thiosulfate is a noncyanide lixiviant for gold leaching. However, the major problem with this leaching method has been the high consumption of reagents. To leach a mild-refractory copper-bearing gold ore, the authors used a reagent combination of 0.3M (NH4)2S2O3, 0.03M CuSO4 and 3M NH3 at pH 10.2 for 24 hours.

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THE STUDY OF THE KINETICS OF GOLD LEACHING IN THE AMMONIUM

The gold leaching rate in ammonium thiosulfate in the presence of copper species is mainly controlled by the cathodic process, which is under diffusion or mixed kinetics control. The results of the rotating gold disk leaching study are consistent with those from the electrochemical study. The

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US6632264B2 - Gold recovery from thiosulfate leaching ...

FIG. 1 is a flow sheet illustrating a process for recovering gold from ammonium thiosulfate (ATS) leach solutions using resin-in-pulp (RIP). FIG. 2 is a flow sheet showing an alternative process...

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Effect of additives on thiosulfate leaching of a gold ore

speed of 250 r/min, 100% leach recovery of gold was achieved with 0.03 M fresh ammonium thiosulfate, 2 mM EDTA after 11 h leach. In a resin-in-leach system, full gold recovery was also achievable with sufficient resin after 24 h leach with 0.06 M fresh ammonium thiosulfate and 2 mM EDTA at an agitation speed of 250 r/min.

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Thermodynamic analysis of gold leaching by

01-11-2001  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 speciation is required to optimize this system.

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Thiosulfate-copper-ammonia leaching of pure gold and ...

Electrochemical gold leaching experiments were performed in three series that consisted of 10 measurements (Table 2). The first two series were carried out using sodium thiosulfate and the third using ammonium thiosulfate. Three variables were chosen for factorial analysis: temperature (20, 30, 40 °C), applied potential of the

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Thiosulphate Leaching SGS

Thiosulfate leaching is particularly well suited to state-of-the-art resin-in-pulp (RIP) gold recovery technologies Thiosulfate leaching is an alkaline process (usually operated in the pH 8 to 10 range) so there are no concerns with corrosion of equipment in the recovery operation; The main chemical components of the thiosulfate leaching process (ammonium thiosulfate and ammonium sulphate) are

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Factors affecting gold leaching in thiosulfate-O2 solutions

30-05-2013  The research into leaching of gold with thiosulfate as an alternative lixiviant to cyanide has predominantly involved the use of copper in the presence of ammonia which serves as the oxidant. However, there are concerns about the health and environmental risks of ammonia (or ammonium).

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Leaching of Gold from the Waste Mobile Phone Printed ...

02-01-2012  Ammonium thiosulfate [(NH 4) 2 S 2 O 3] is a leachant which is non-toxic as well as economical. It works to stabilize gold as anionic complex which is mainly accountable for the gold recovery. Thiosulfate leaching has many advantages over the cyanidation process including higher leaching rates and less interference from foreign ions.

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1-Ammonium Thiosulfate Ecological Viable Alternative to ...

Reaction leaching of precious metals with ammonium thiosulfate: add copper with thiosulfate and ammonia produce that the gold is dissolved quickly in comparison with the process that uses cyanide. The gold leaching is produced according to the reaction in Eq. (1) [2]: 23 2

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US8597399B2 - Method for thiosulfate leaching of

Processes are provided for recovering precious metals from refractory materials using thiosulfate lixiviants. The processes can employ lixiviants that include at most only small amounts of copper and/or ammonia and operate at a relatively low pH, reduction of polythionates, inert atmospheres to control polythionate production, and electrolytic solutions which provide relatively high rates of precious metal

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Leaching of Gold from the Waste Mobile Phone Printed ...

02-01-2012  A leaching of 56.7% gold was obtained under the optimum condition of 0.1M ammonium thiosulfate, 40 mM copper sulfate, pH: 10-10.5, pulp density: 10 g/L at room temperature and stirring speed of 250 rpm in 8h duration. The maximum leaching of gold in the pH range 10-10.5 may be attributed to the higher stability of the ammonium thiosulfate.

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Thermodynamic analysis of gold leaching by

01-11-2001  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 speciation is required to optimize this system.

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Study on Gold Extraction from Thiosulfate-Ethylenediamine ...

25-03-2020  95%, ammonium thiosulfate concentration is selected as 0.3mol/L, copper ion concentration is selected as 0.005mol/L, ethylenediamine concentration is selected as 0.06mol/L, and the pH value is adjusted to bout 10, liquid to solid mass ratio of 3:a 1, stirring and leaching at room temperature for h, on this basis, the gold leaching rate 7 is

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Thiosulfate Leaching Process for Gold Extraction

Thiosulfate leaching appears to be one of the most promising alternatives to cyanidation. Understanding gold thiosulfate leaching system plays a crucial role in order to effectively extract gold, in which the kinetics and equilibrium adsorption of thiosulfate, polythionates, gold thiosulfate and copper onto resin in

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1-Ammonium Thiosulfate Ecological Viable Alternative to ...

Reaction leaching of precious metals with ammonium thiosulfate: add copper with thiosulfate and ammonia produce that the gold is dissolved quickly in comparison with the process that uses cyanide. The gold leaching is produced according to the reaction

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Leaching of gold and silver from printed circuit board of ...

Leaching of PCB's with sodium thiosulfate and ammonium thiosulfate. In this step, sodium and ammonium thiosulfate were used to extract gold and silver of whole PCBs. In both leachates, the effect of adding copper, as a catalyst agent, and hydrogen peroxide, as the oxidizing agent to

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(PDF) Leaching of Gold from Mobile Phone Manoj Kumar ...

The present work deals with the recovery of gold using ammonium thiosulfate as a leaching agent from waste mobile PCBs containing 0.021% Au, 0.1% Ag, 56.68% Cu, 1.61% Ca, 1.42% Al, 1.40% Sn, 0.24% Fe, 0.22% Zn, 0.01% Pd etc.. The cutting granules of 0.5 -3.0 mm PCBs were used for leaching in a 500 mL glass beaker in open atmosphere.

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US8597399B2 - Method for thiosulfate leaching of

Processes are provided for recovering precious metals from refractory materials using thiosulfate lixiviants. The processes can employ lixiviants that include at most only small amounts of copper...

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Method for leaching precious metals containing ores

Methods, systems and lixiviation compositions including an ammonium thiosulfate or a non-ammonium thiosulfate component in combination with one or more alkaline earth metal hydroxides, and optionally copper cations, for leaching precious metals from a precious metal containing material.

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DISSOLUTION OF GOLD WITH CYANIDE REPLACING REAGENTS

queries. The aim of this paper is to study leaching of gold with cyanide replacing alternatives such as ammonium thiosulfate, chloride-hypochlorite, thiourea and thiocyanate to provide new cases for the tool. The behaviour of gold was examined with electrochemical tests and weight loss measurements a using

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Thermodynamic analysis of gold leaching by

01-11-2001  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 speciation is required to optimize this system.

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Study on Gold Extraction from Thiosulfate-Ethylenediamine ...

25-03-2020  95%, ammonium thiosulfate concentration is selected as 0.3mol/L, copper ion concentration is selected as 0.005mol/L, ethylenediamine concentration is selected as 0.06mol/L, and the pH value is adjusted to bout 10, liquid to solid mass ratio of 3:a 1, stirring and leaching at room temperature for h, on this basis, the gold leaching rate 7 is

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NICKEL AMMONIUM THIOSULPHATE LEACHING OF GOLD

Ammonium thiosulphate leaching is considered as one of the promising alternatives to cyanidation in hydrometallurgy. However, its industrial application is limited due to the high reagent consumption which has a direct impact on its cost-effectiveness. This research aimed to investigate the ammonium thiosulphate leaching of gold from waste mobile

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(PDF) Leaching of Gold from Mobile Phone Manoj

The present work deals with the recovery of gold using ammonium thiosulfate as a leaching agent from waste mobile PCBs containing 0.021% Au, 0.1% Ag, 56.68% Cu, 1.61% Ca, 1.42% Al, 1.40% Sn, 0.24% Fe, 0.22% Zn, 0.01% Pd etc.. The cutting granules of 0.5 -3.0 mm PCBs were used for leaching in a 500 mL glass beaker in open atmosphere.

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Thiosulfate Leaching Process for Gold Extraction

Thiosulfate leaching appears to be one of the most promising alternatives to cyanidation. Understanding gold thiosulfate leaching system plays a crucial role in order to effectively extract gold, in which the kinetics and equilibrium adsorption of thiosulfate, polythionates, gold thiosulfate and copper onto resin in

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How To Use Ammonium Sulfate For Gold Leaching

Thiosulfate Leaching Of Golda Review. 2013-1-30Chalcopyrite ores containing gold were leached in ammonium sulfate with an 02 over-pressure of 20 psi before treatment with 65-130 gL of ammonium thiosulfate within pH values of 8.5 to 9.5.

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(PDF) Thiosulfate leaching of gold from waste mobile ...

Thiosulfate leaching of gold from waste mobile phones Ha V.H., Lee J.-C., Jeong J., Hai H.T., Jha M.K. Institute for Environmental Science and Technology, Hanoi University of Technology (HUT), 1 - Dai Co Viet, Hanoi, Viet Nam; Mineral Resources Research Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), 92, Gwahang-no, Yuseong-gu, Daejeon 305-350, South Korea; Metal ...

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Method for thiosulfate leaching of precious metal ...

Gelves, G.A. et al.; “Recovering of Refractory Gold Using Ammonium Thiosulfate Solutions,” Clean Technology for the Mining Industry, Proceeding of the III International Conference on Clean Technologies for the Mining Industry held in Santiago, Chile, May 15-17, 1996, pp. 477-487.

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Method for leaching precious metals containing ores

Methods, systems and lixiviation compositions including an ammonium thiosulfate or a non-ammonium thiosulfate component in combination with one or more alkaline earth metal hydroxides, and optionally copper cations, for leaching precious metals from a precious metal containing material. The alkaline earth metal hydroxides may include magnesium hydroxide, calcium hydroxide, or a combination of ...

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1-Ammonium Thiosulfate Ecological Viable Alternative to ...

sodium cyanide by ammonium thiosulfate, minimizing the toxic risk to the environment including the public and occupational health. Ammonium thiosulfate does not cause appreciable damage using conservative quantities in addition it has the benefit of being an aqueous solvent for leaching gold

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