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gold leaching thiocyanate

A review of thiocyanate gold leaching Chemistry

Jan 01, 2021 Thiocyanate gold leaching requires an oxidant, such as Fe 3+, and pH values between 1 and 2 (Barbosa-Filho and Monhemius, 1989, Li et al., 2012a), or 1 and 3 (Munoz and Miller, 2000). The discrepancy between these pH ranges is thought to be attributed to the mineralogy of the ore samples, the oxidant type, and the oxidant concentration. Gold

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THIOCYANATE LEACHING OF GOLD

THIOCYANATE LEACHING OF GOLD by Roselyn Sarpomah Yeboah B.Sc., University of Mines and Technology-Tarkwa Ghana, 2015 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES

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Thiocyanate hydrometallurgy for the recovery of gold

Feb 01, 2012 Acid thiocyanate leaching of gold was investigated in the presence of ferric sulfate as an oxidant. According to leaching kinetic studies the initial rate of gold leaching is slow, and not significantly dependent on thiocyanate (0.05–0.2 M) and ferric (0.1–1.0 g/L) concentrations.Ferrous and cupric ions had no effect on leaching kinetics under the conditions studied.

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A review of thiocyanate gold leaching Chemistry

Thiocyanate gold leaching is an electrochemical reaction which occurs at pH 1.5–2.5 and electrochemical potential of 600–700 mV. The literature shows fast gold leaching kinetics in well-designed thiocyanate systems. The solubilized gold-thiocyanate species can be recovered from the pregnant leach solution by a variety of methods including

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Thiocyanate Leaching of Gold Hydrometallurgy: Leaching

The leaching of gold ores by acid solutions of thiocyanate produces two complexes, Au(SCN)2- and Au(SCN)4-. The reaction involves oxidation. It is believed that the addition of Iron III is a good oxidant.

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Thiourea–thiocyanate leaching system for gold ScienceDirect

Feb 01, 2011 The gold leaching rate decreases with time and ferric concentration has only a minor effect on the rate of gold dissolution. (2) A u + F e 3 + + 2 S C N − → A u (S C N) 2 − + F e 2 + In thiourea–thiocyanate solutions, the gold leaching rate remains constant with time, which means the mixed ligand exhibits behavior similar to thiourea

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Thiocyanate leaching of gold UBC Library Open Collections

This study focused on evaluating sodium thiocyanate as an alternative reagent to the conventional cyanidation process for leaching of gold ores. Goldcorp’s Coffee project in Yukon-Canada supplied three mineral samples namely, Supremo Oxide 68151, Supremo oxide 68151, Supremo Composite 72142 for this study. As a baseline for comparison with thiocyanate extraction results, cyanidation tests

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Thiocyanate hydrometallurgy for the recovery of gold. Part

Feb 01, 2012 Highlights Thermodynamic analysis of (Au, Ag, Cu, Fe)-SCN-H 2 O systems was performed. The findings are useful in understanding the leaching and recovery of gold. Gold can be leached in thiocyanate solutions with ferric sulfate as the oxidant. Gold forms aurous or auric complexes with thiocyanate. Ferric ion forms a series of cationic or anionic complexes with thiocyanate.

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Gold Metallurgy & Leaching in Cyanicides

Jul 14, 2016 How Thiocyanate Affect Gold Leaching. The reason for the lower cyanide consumption obtained with intense aeration is probably connected with the reactions which take place when alkaline sulphide decomposes in cyanide solution. Alkaline sulphide is one of the initial products of the reaction between pyrrhotite and alkaline cyanide solution.

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Gold Metallurgy and Leaching Process

Jun 24, 2015 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., to achieve either one or two purposes:

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Thiocyanate leaching of gold UBC Library Open Collections

This study focused on evaluating sodium thiocyanate as an alternative reagent to the conventional cyanidation process for leaching of gold ores. Goldcorp’s Coffee project in Yukon-Canada supplied three mineral samples namely, Supremo Oxide 68151, Supremo oxide 68151, Supremo Composite 72142 for this study. As a baseline for comparison with thiocyanate extraction results, cyanidation

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Leaching of gold in acid thiourea-thiocyanate solutions

The leaching of gold in ferric-thiourea-thiocyanate solutions has been studied by the rotating-disk technique. The effects of initial concentrations of ferric, thiourea (Tu), thiocyanate, temperature and pH value on gold leaching rate were studied. Determinations of apparent activation energy indicate that the process was controlled by a combination of chemical reaction and diffusion in the

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"Thiourea-thiocyanate Leaching System For Gold" by Xiyun

The leaching of gold in thiourea-thiocyanate solutions has been studied by the rotating-disc technique using ferric sulfate as oxidant. The effects of initial concentrations of ferric, thiourea (Tu) and thiocyanate as well as temperature and pH on gold leaching rates were studied. An initial gold leaching rate in the order of 10− 9 mol cm− 2 s− 1 was obtained at 25 °C, which was higher

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University of Utah Institutional Repository Author

A possible alternative reagent to cyanide for gold leaching is thiocyanate, as first reported by White (1905). However, it was not until 1986 that research on the subject was resumed by Fleming (1986). A thermodynamics study of the thiocyanate system for leaching of gold and silver ores was published by Barbosa-Filho and Monhemius (1989).

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A Review of Thiocyanate Hydrometallurgy for the Recovery

Recently, ammonium thiocyanate was selected as leaching reagent in the laboratory study. Just as some papers shown, thiocyanate can be complexed tightly with Au+ or Au3+ to form water-soluble complexes according to the dynamic and thermodynamic system of thiocyanate gold and regenerated or obtained as a by-product in technological processes.

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Hydrometallurgical Recovery of Gold from Mining Wastes

Nov 11, 2020 Generally, gold leaching using thiocyanate (0.01–0.05 M) occurs at a potential of 0.4–0.45 V, pH 1–3, in the presence of an oxidant like ferric ions (2–5 g/L) or peroxide. It has been shown that, under optimal conditions, a gold extraction yield of 95% can be achieved . Thiocyanate concentrations in the range of 0.5 to 5 g/L and Fe (III

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the effect of sodium thiocyanate on gold cyanidation

Thiocyanate hydrometallurgy for the recovery of gold Sodium thiocyanate (98 The effect of thiocyanate concentration on the rate of As an alternative to cyanidation, thiocyanate leaching of gold was investigated

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Leaching Pyrite Gold Ore without Cyanide

Sep 09, 2017 Figure 9 shows the results for gold leaching at [SC (NH2)2]0 of 0.15 M (11.4 g/L) and [Fe+3]0 of 0.02 M (1.12 g/L) and pH 2. As with the thiocyanate lixiviant, gold dissolution of the ore without chemical pretreatment was very low, compared to the ore with pretreatment. Without chemical pretreatment, 27.6% of the gold was dissolved, while with

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Gold Leaching Scientific.Net

Recently, ammonium thiocyanate was selected as leaching reagent in the laboratory study. Just as some papers shown, thiocyanate can be complexed tightly with Au + or Au 3+ to form water-soluble complexes according to the dynamic and thermodynamic system of thiocyanate gold and regenerated or obtained as a by-product in technological processes

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Gold Metallurgy and Leaching Process

Jun 24, 2015 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., to achieve either one or two purposes:

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CN104232922A Sodium cyanate gold leaching technology

The invention discloses a sodium cyanate gold leaching technology, comprising the steps of: grinding gold concentrate to enable 400-mesh particles to be 85%-95% of grinded gold concentrate, mixing to be thick liquid with a liquid-solid mass ratio of 2:1 to 5:1, adding 8kg/t of Cao4 and 1-3kg/t of Na2CO3 as leaching agents, adjusting a system pH value to be 9-12, adding 0.05-0.8% of sodium

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Leaching Roaster Calcine Leach Residues with Aqueous

This paper presents the results of research work conducted to assess if aqueous solutions of sulfur dioxide (SO2) can be used to treat roaster calcine leach residues such that recovery of gold in this material can be achieved with subsequent application of the thiocyanate (SCN-) leaching system. The project is mainly aimed at assessing an alternative use for sulfur dioxide gas generated during

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"Thiourea-thiocyanate Leaching System For Gold" by Xiyun

The leaching of gold in thiourea-thiocyanate solutions has been studied by the rotating-disc technique using ferric sulfate as oxidant. The effects of initial concentrations of ferric, thiourea (Tu) and thiocyanate as well as temperature and pH on gold leaching rates were studied. An initial gold leaching rate in the order of 10− 9 mol cm− 2 s− 1 was obtained at 25 °C, which was higher

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Thiocyanate Leaching of Gold Mitacs

Thiocyanate Leaching of Gold. Cyanide is a chemical used in the dissolution of gold. It is highly toxic and environmentally unfriendly but cheap and highly efficient. In Canada, more than 90% of the gold mines uses cyanide in its operation, however, the toxicity of cyanide after some serious cyanide accidents has raised the alarm for

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Electrochemical dissolution behavior of gold and its main

Jan 07, 2021 The thiocyanate system can complete gold leaching under acidic and alkaline conditions, and the effect of acid thiocyanate leaching is better [6,7,8,9,10,11,12,13,14]. The thiocyanate system consists of thiocyanate and oxidant and can leach gold directly from ore, concentrate calcine and waste printed circuit boards.

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Thiocyanate Part 1: A Problem in Gold Mining BQE Water

Jun 23, 2021 Thiocyanate is a growing environmental challenge for the gold industry. Harmful to both humans and aquatic life, thiocyanate presence is becoming more prevalent in gold mining effluents. It is formed when cyanide reacts with sulphur containing minerals and/or compounds released into solution during the metallurgical extraction of gold. Ore bodies rich in pyrrhotite, an iron []

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A Review of Thiocyanate Hydrometallurgy for the Recovery

Recently, ammonium thiocyanate was selected as leaching reagent in the laboratory study. Just as some papers shown, thiocyanate can be complexed tightly with Au+ or Au3+ to form water-soluble complexes according to the dynamic and thermodynamic system of thiocyanate gold and regenerated or obtained as a by-product in technological processes.

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the effect of sodium thiocyanate on gold cyanidation

Thiocyanate hydrometallurgy for the recovery of gold Sodium thiocyanate (98 The effect of thiocyanate concentration on the rate of As an alternative to cyanidation, thiocyanate leaching of gold was investigated

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"Thiocyanate Hydrometallurgy For the Recovery of Gold Part

Thiocyanate has been identified and studied as a promising alternative lixiviant for gold in acidic solutions. Eh-pH and ion species distribution diagrams for SCN-H2O, Au-SCN-H2O, Ag-SCN-H2O, Cu-SCN-H2O, and Fe-SCN-H2O systems were constructed to predict the behavior of each metal ion in the thiocyanate system and also to explain the experimental results.

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Leaching Pyrite Gold Ore without Cyanide

Sep 09, 2017 Figure 9 shows the results for gold leaching at [SC (NH2)2]0 of 0.15 M (11.4 g/L) and [Fe+3]0 of 0.02 M (1.12 g/L) and pH 2. As with the thiocyanate lixiviant, gold dissolution of the ore without chemical pretreatment was very low, compared to the ore with pretreatment. Without chemical pretreatment, 27.6% of the gold was dissolved, while with

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DISSOLUTION OF GOLD WITH CYANIDE REPLACING REAGENTS

Keywords: gold leaching, ammonium thiosulfate, chloride, thiourea, thiocyanate Introduction The most common hydrometallurgical methods of primary raw material utilization in the production of gold are based on the use of cyanide (Hilson, 2006). In this method a weak sodium cyanide solution (NaCN) of 100-500 ppm is used. Since the Baia Mare

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Gold Metallurgy and Leaching Process

Jun 24, 2015 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., to achieve either one or two purposes:

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Noncyanide leaching of an auriferous pyrite ore from Ecuador

Aug 01, 2000 Gold leaching of an auriferous pyrite ore from the Portovelo deposit in Ecuador indicates that noncyanide leaching systems, such as thiocyanate and thiourea, are not as effective as the traditional cyanide system. For example, whereas approximately 95% of the gold can be leached from the ore with cyanide, only about 50% gold dissolution can be achieved with a thiocyanate leaching

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Gold Leaching Scientific.Net

Recently, ammonium thiocyanate was selected as leaching reagent in the laboratory study. Just as some papers shown, thiocyanate can be complexed tightly with Au + or Au 3+ to form water-soluble complexes according to the dynamic and thermodynamic system of thiocyanate gold and regenerated or obtained as a by-product in technological processes

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UTILIZING CYANIDE RECOVERY TECHNIQUES IN THE CESL

consumption of the leach. The CESL Gold-Silver Process uses pressure cyanidation to reduce gold and silver leaching time from conventional lengths of 24-48 hours down to 60-90 minutes to minimize thiocyanate leaching. Gold and silver are recovered from the resulting leach solution

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Sodium Thiosulphate Gold Leaching

Jun 02, 2016 The gold industry has been seeking alternative reagents for leaching gold from low-grade ores for the past 25 years. The cost and transport of cyanide, the poor recovery of gold from carbonaceous ores, the lack of selectivity of cyanide towards copper minerals and the cost of waste treatment are real factors which can make cyanide unattractive in some circumstances.

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