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thermodynamics of gold leaching from its ores

Thermodynamic analysis of gold leaching by ammoniacal ...

2001-11-1  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 NH 3 and S 2 O 3 2−.It is shown that an understanding of the copper speciation and sulfur speciation is required to optimize this system.

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(PDF) Leaching of gold in thiocyanate solutions. Part 1 ...

The article discusses four alternative cyanide substitutes for the recovery of gold from ores and concentrates. Cyanide has been the premier gold leach reagent for over 100 years due to its

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Leaching of gold and copper minerals in cyanide deficient ...

2005-8-1  The concept of leaching copper–gold ores using leach solutions which contain Cu (CN) 32− was investigated. Gold leaching occurs in air saturated Cu (CN) 32− solutions at a much slower rate than in free cyanide solutions. A similar gold leach rate is observed when copper is alloyed with the gold.

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Thiosulphate leaching of gold in the Cu–NH3–S2O32−–H2O ...

Thermodynamic analyses were conducted for gold leaching in Cu–NH 3 –S 2 O 32− –H 2 O system.

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A review of thiocyanate gold leaching – Chemistry ...

2021-1-1  Gold leaching by thiocyanate as a promising less toxic lixiviant than cyanide. • Thiocyanate resonances and its coordination with gold using Infrared spectroscopy were investigated. • Effective parameters on thermodynamics and kinetics of thiocyanate gold leaching were studied. • Optimum condition of gold leaching using thiocyanate was ...

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Thiosulphate leaching of gold in the Cu–NH3–S2O32−–H2O ...

2020-6-1  Thermodynamic analyses were conducted for gold leaching in Cu–NH 3 –S 2 O 32− –H 2 O system.

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(PDF) A review of thiocyanate gold leaching – Chemistry ...

Thiocyanate is 1000 times less toxic than cyanide and is a very strong gold leaching lixiviant. This review paper provides an overview of the chemistry, thermodynamics, kinetics, and processing of ...

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The mechanism of gold extraction and copper precipitation ...

1997-3-1  These Cu (l)cyanide ions are responsible for gold leaching in the absence of free cyanide. Copper precipitation occurs as a parallel process, leaving sufficient Cu (1)cyanide for gold leaching. The critical value of oxygen concentration in the system was established which separates the areas of thermodynamic stability of CuCN and CuO/ Cu (OH)2.

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The Chemistry of the Extraction of Gold - SAIMM

2011-5-29  The Chemistry of the Extraction of Gold M.J. Nicol, C.A. Fleming and R.L. Paul 1S.1 General Principles 15.1.1 The chemistry of gold compounds Gold is the most noble of all the metals and this .is the key to both its eternal romance and its many practical uses in industry. It is the only metal, for

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Recovery of gold from refractory gold ores: Effect of ...

2021-6-5  Recovery of gold from refractory gold ores: Effect of pyrite on the stability of the thiourea leaching system Hong Qin1), Xue-yi Guo1,2), Qing-hua Tian1,2), and Lei Zhang1) 1) School of Metallurgy and Environment, Central South University, Changsha 410083, China

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Thermodynamic analysis of gold leaching by ammoniacal ...

2001-11-1  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 NH 3 and S 2 O 3 2−.It is shown that an understanding of the copper speciation and sulfur speciation is required to optimize this system.

More

Thermodynamic and kinetic limitations of gold leaching in ...

The global gold industry is under increasing pressure to search for alternative technologies to replace cyanidation due to the inefficiency of cyanide in treating low grade refractory gold ores and increased public scrutiny on the use of cyanide in gold mining. Chloride has been identified as a promising candidate to replace cyanide. The objective of this research was to gain fundamental ...

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Thiosulphate leaching of gold in the Cu–NH3–S2O32−–H2O ...

2020-6-1  The stability of S 2 O 3 2− is important for thiosulphate leaching of gold and its recovery from thiosulphate solutions such as using ion-exchange resins. The Eh–pH diagram in Fig. 3(a) and speciation diagram in Fig. 3(b) show the thermodynamic stability of S 2 O 3 2− in the S 2 O 3 2− –NH 3 –H 2 O system. In the absence of NH 4 (S 2 O 3) −, a narrow elongated Eh–pH ...

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Thermodynamic analysis of ammoniacal thiosulphate

2+ (x=1–6) can be formed and drive the dissolution of gold in ammoniacal thiosulphate solutions. Based on the diagrams, a possible mechanism for the Co(III)/Co(II) electrochemical-catalytic leaching

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HYDROMETALLURGY OF GOLD: NEW PERSPECTIVES AND

2003-11-17  very recent technique, its kinetics and thermodynamics are not yet well clarified. Refractory gold ores Refractory ores are characterized by low recoveries and high reagent consumption when subjected to direct leaching and several attempts have been done to

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Ammoniacal thiosulphate leaching of gold ore

2015-12-27  the leaching systems were fluctuating 150−160 and 170−180mV vs. SHE respectively. The times of leaching were restricted for about 5h for the rest of the leaching experiments. Figure 1. Ammoniacal thiosulphate leaching of Akeshi and Hishikari gold ores a) as a function of time and b) as a function of pH and E

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Recovery of gold from refractory gold ores: Effect of ...

2021-6-5  Recovery of gold from refractory gold ores: Effect of pyrite on the stability of the thiourea leaching system Hong Qin1), Xue-yi Guo1,2), Qing-hua Tian1,2), and Lei Zhang1) 1) School of Metallurgy and Environment, Central South University, Changsha 410083, China

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Recovery of gold from refractory gold ores: Effect of ...

2020-5-28  The extraction of gold from refractory gold ores (RGOs) without side reactions is an extremely promising endeavor. However, most RGOs contain large amounts of sulfide, such as pyrite. Thus, investigation of the influence of sulfide on the gold leaching process is important to maximize the utilization of RGOs. In this work, the effects of pyrite on the stability of the thiourea system were ...

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(PDF) Chloride Leaching of Copper Sulfide Ores: Some Notes ...

2021-8-5  Heap leaching low-grade ores has become a major contributor to the extraction of economically important metals, notably copper and gold. The state-of-the-art in heap leaching

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Comparative Study of Gold Extraction from Refractory ...

2020-5-7  Pressure oxidation is a hydrometallurgical oxidative pretreatment for refractory ores, such as sulfide ores. Here, simultaneous alkaline pressure oxidation and sodium cyanide leaching treatments were carried out on a pyritic ore from the Mulatos Mine located in Sahuaripa, Sonora, Mexico. Mineral characterization, agitation leaching, hot cyanidation under atmospheric pressure conditions ...

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Thermodynamic analysis of gold leaching by ammoniacal ...

2001-11-1  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 NH 3 and S 2 O 3 2−.It is shown that an understanding of the copper speciation and sulfur speciation is required to optimize this system.

More

Thermodynamic and kinetic limitations of gold leaching in ...

The global gold industry is under increasing pressure to search for alternative technologies to replace cyanidation due to the inefficiency of cyanide in treating low grade refractory gold ores and increased public scrutiny on the use of cyanide in gold mining. Chloride has been identified as a promising candidate to replace cyanide. The objective of this research was to gain fundamental ...

More

Ammoniacal thiosulphate leaching of gold ore

2015-12-27  the leaching systems were fluctuating 150−160 and 170−180mV vs. SHE respectively. The times of leaching were restricted for about 5h for the rest of the leaching experiments. Figure 1. Ammoniacal thiosulphate leaching of Akeshi and Hishikari gold ores a) as a function of time and b) as a function of pH and E

More

HYDROMETALLURGY OF GOLD: NEW PERSPECTIVES AND

2003-11-17  very recent technique, its kinetics and thermodynamics are not yet well clarified. Refractory gold ores Refractory ores are characterized by low recoveries and high reagent consumption when subjected to direct leaching and several attempts have been done to

More

Leaching of gold ores with high cyanicides: a physico ...

2021-8-9  size reduction of gold ores and a simulator of gold grain exposure of ground ore to add the liberation of the gold ore to the leaching model [9, 10]. Bellec et al. (2009) [11] have proposed an empirical model that is a function of the ore particle size distribution, and cyanide, copper, and sulfur concentrations. In their leaching model,

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(PDF) Thiosulfate leaching of gold—A review Mark Aylmore ...

Hemmati et al. (1989) investigated the thiosulfate leaching of gold from carbonaceous ore that contained 2.5% organic carbon. The optimum conditions for gold extraction were found to be 35°C and 103 kPa oxygen over pressure, pH 10.5, 3M NH3 with a lixiviant containing 0.71M (NH4)2S203, 0.15M CuSO4 and 0.1M (NH4)2SO3.

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Leaching of Precious Metals from Complex Sulphide Ores.

2007-10-24  (1992). Leaching of Precious Metals from Complex Sulphide Ores. On the Chemistry of Gold Lixiviation by Thiourea. Mineral Processing and Extractive Metallurgy Review: Vol. 11, No. 1

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A review of gold extraction using noncyanide lixiviants ...

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 reagents.

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Comparative Study of Gold Extraction from Refractory ...

2020-5-7  Pressure oxidation is a hydrometallurgical oxidative pretreatment for refractory ores, such as sulfide ores. Here, simultaneous alkaline pressure oxidation and sodium cyanide leaching treatments were carried out on a pyritic ore from the Mulatos Mine located in Sahuaripa, Sonora, Mexico. Mineral characterization, agitation leaching, hot cyanidation under atmospheric pressure conditions ...

More

Gold CIL CIP Gold Leaching Process Explained CCD

2013-1-2  Counter-current leaching. leaching efficiency can be enhanced by the application of Le Chatelier’s principle. In summary, the lower the concentration of gold in solution, the greater the driving force for gold dissolution to occur, although in a mass transport controlled reaction it is debatable what role this plays in gold leaching.

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