thiocyanate leaching of gold

  • A Review on Alternative Gold Recovery Re agents to Cyanide

    The target of this review is to point out the best cyanide free processes of following methods and reagents Bioleaching, Chlorination, Aqua Regia, Bromine, Thiocyanate, Thiosulfate and Thiourea leaching. For this propose, the gold leaching reagents are described and discussed in terms of their environmental and economical points of view.

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  • The role of glycine in the ammonium thiocyanate leaching

    Thiocyanate leaching is an efficient and environmentally friendly method to extract gold due to fast leaching speed, excellent reaction selectivity and slight environmental risks, but thiocyanate is easily oxidized to decompose by oxidant in the leaching process, resulting in large consumption of leaching

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  • Thiocyanate hydrometallurgy for the recovery of gold

    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 (0.050.2 M) and ferric (0.11.0 g/L) concentrations.

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  • US7025942B2 Control of lead nitrate addition in gold

    A method for controlling the extraction of gold from a gold ore by the cyanidation process in which a leaching step including the addition of a lead compound, which is typically lead nitrate or other lead salt, is used. In order to maintain stable conditions in the leaching process, and to use the leaching reagents efficiently, an analysis step is used to monitor the concentration of

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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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  • CYANIDE REMEDIATION CURRENT AND PAST

    CYANIDE REMEDIATION CURRENT AND PAST TECHNOLOGIES leaching, particularly gold. These technologies are environmentally sound but require safeguards to prevent accidental spills from contaminating soils as well as surface and ground waters. Various methods of cyanide remediation by separation and oxidation are thiocyanate, oxidation

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  • Alternative Lixiviants to Cyanide for Leaching Gold Ores

    Iron could be used for gold cementation in thiocyanate solutions where ferric iron is used as an oxidant in thiocyanate gold leaching systems. The barren thiocyanate solutions left after gold cementation can be recycled back to the leaching step and reused (Wang et al., 2007a,b).

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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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  • Use in Mining International Cyanide Management Code

    Gold and silver typically occur at very low concentrations in ores less than 10 g/t or 0.001% (mass basis). At these concentrations the use of aqueous chemical (hydrometallurgical) extraction processes is the only economically viable method of extracting the gold and silver from the ore. Typical hydrometallurgical recovery involves a leaching step during which the metal is dissolved in an

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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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  • The Chemistry of the Extraction of Gold SAIMM

    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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  • 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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  • A Review on Alternative Gold Recovery Reagents to Cyanide

    Chlorination, Aqua Regia, Bromine, Thiocyanate, Thiosulfate and Thiourea leaching.For this pro pose, the gold leaching reagents are described and discussed in terms of their environmental and economical points of view. As result of this comparison, thiourea stands out as the most promising alternative gold leaching reagent to cya nide. Keywords

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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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  • Gold cyanidation

    Gold cyanidation (also known as the cyanide process or the MacArthur Forrest process) is a hydrometallurgical technique for extracting gold from low grade ore by converting the gold to a water soluble coordination complex.It is the most commonly used leaching process for gold extraction Production of reagents for mineral processing to recover gold, copper, zinc and silver represents

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  • A Review on Alternative Gold Recovery Re agents to Cyanide

    The target of this review is to point out the best cyanide free processes of following methods and reagents Bioleaching, Chlorination, Aqua Regia, Bromine, Thiocyanate, Thiosulfate and Thiourea leaching. For this propose, the gold leaching reagents are described and discussed in terms of their environmental and economical points of view.

    Live Chat
  • Thiocyanate Hydrometallurgy For the Recovery of Gold Part

    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.

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  • Using Nickel as a Catalyst in Ammonium Thiosulfate

    Using Nickel as a Catalyst in Ammonium Thiosulfate Leaching for Gold Extraction Harunobu Arima1, Toyohisa Fujita2 and Wan Tai Yen3 1Graduate Student, Queens University.Present address Akita Zinc Co., , Akita 011 8555, Japan

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  • A Review of Thiocyanate Hydrometallurgy for the Recovery

    Over the past century, numbers of hydrometallurgical processing technologies have been conducted for gold leaching in mining and second resource, such as cyanidation, being with high toxicity and low reaction rate, and non cyanide thiosulphate leaching and thiourea leaching, etc, having relatively high reagent consumption. Recently, ammonium thiocyanate was selected as leaching reagent in

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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

    Live Chat
  • Iodidethiocyanate leaching system for gold SpringerLink

    The instability of these intermediate species towards hydrolysis is a major drawback of the iron(III) thiocyanate leaching system, which can be overcome by additions of small amounts of I and/or I 2. Experiments revealed a synergistic effect of the thiocyanate iodide mixture on the dissolution of gold.

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  • Recovery of Gold from Thiourea, Thiocyanate, or

    Sodium borohydride can be used as an efficient agent for reducing gold and silver in acidic solutions of thiourea, thiocyanate, thiosulfate, acid chloride, and acid nitrate. The Au(I) ion is reduced to metallic gold in the form of very fine crystals, as indicated by XRD and SEM analysis.

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  • Thioureathiocyanate leaching system for gold ScienceDirect

    The leaching of gold in thioureathiocyanate 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.

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  • Alternative lixiviants to cyanide for leaching gold ores

    9. THIOCYANATE LEACHING Thiocyanate has been known for a long time to act as a lixiviant for gold. Early work examined acidic thiocyanate solutions to recover gold and uranium simultaneously from South African gold ores (Fleming, 1986).

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  • Thioureathiocyanate leaching system for gold Request PDF

    The leaching of gold in thioureathiocyanate solutions has been studied by the rotating disc technique using ferric sulfate as oxidant. The effects of initial concentrations of ferric, thiourea

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  • A Review of Thiocyanate Hydrometallurgy for the Recovery

    Over the past century, numbers of hydrometallurgical processing technologies have been conducted for gold leaching in mining and second resource, such as cyanidation, being with high toxicity and low reaction rate, and non cyanide thiosulphate leaching and thiourea leaching, etc, having relatively high reagent consumption. Recently, ammonium thiocyanate was selected as leaching reagent in

    Live Chat
  • Using Nickel as a Catalyst in Ammonium Thiosulfate

    Using Nickel as a Catalyst in Ammonium Thiosulfate Leaching for Gold Extraction Harunobu Arima1, Toyohisa Fujita2 and Wan Tai Yen3 1Graduate Student, Queens University.Present address Akita Zinc Co., , Akita 011 8555, Japan

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  • CHLORIDE HYPOCHLORITE OXIDATION AND LEACHING

    Chloridehypochlorite oxidation and leaching of refractory sulfide gold concentrate 63 Fig. 1. The Pourbaix diagram of FeS at [Fe] = 10 4 M, [S] = 10 M and 25 C (the chlorine species regions are also marked) (Marsden and House, 2005) Fig. 2.

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  • Gold Metallurgy amp; Leaching in Cyanicides

    Metallurgical ContentRecovering Gold from Iron SulphidesHow Thiocyanate Affect Gold LeachingUsing Lead Salts in Gold LeachingHow Ferrocyanides influences Gold LeachingEffect of pre aeration on gold leach recoveryHow the method of pre lime treatment affects gold leachingDirect Leaching in Grinding CircuitA trick to reduce cyanide consumptionGold Leaching with Copper Minerals presentLeaching

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  • THE CESL GOLD PROCESS teck

    it is no longer available for gold and silver leaching and it is difficult to recover cyanide from thiocyanate once formed. CN + So SCN (1) Third, the elemental sulphur can exist as a coating on some of the copper plant residue particles.

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  • (PDF) Iodidethiocyanate leaching system for gold

    PDF The leaching of gold by thiocyanate solutions is performed at pHs between 1 and 2, which allows the use of iron(III) as an oxidizing agent. The mechanism of dissolution of gold by iron(III

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  • Cyanide and Other Lixiviant Leaching Systems for Gold with

    Selection of a leaching system for gold involves consideration of ore texture and mineralogy, chemical requirements, leaching techniques, the development of flowsheets, and environmental management. Aqueous dissolution chemistry for alkaline, neutral, and acid systems is mainly considered here. All systems require an oxidant to oxidise gold and a ligand to complex with gold in solution.

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  • Gold(III) Potassium Thiocyanate AMERICAN ELEMENTS

    Gold(III) Potassium Thiocyanate is generally immediately available in most volumes. High purity, submicron and nanopowder forms may be considered. American Elements produces to many standard grades when applicable, The role of glycine in the ammonium thiocyanate leaching of gold.

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  • Thiourea thiocyanate Leaching System For Gold

    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.

    Live Chat
  • US7025942B2 Control of lead nitrate addition in gold

    A method for controlling the extraction of gold from a gold ore by the cyanidation process in which a leaching step including the addition of a lead compound, which is typically lead nitrate or other lead salt, is used. In order to maintain stable conditions in the leaching process, and to use the leaching reagents efficiently, an analysis step is used to monitor the concentration of

    Live Chat
  • Thiocyanate hydrometallurgy for the recovery of gold. Part

    Thiocyanate has been identified and studied as a promising alternative lixiviant for gold in acidic solutions. E h pH and ion species distribution diagrams for SCNH 2 O, AuSCNH 2 O, AgSCNH 2 O, CuSCNH 2 O, and FeSCNH 2 O systems were

    Live Chat
  • Gold(III) Potassium Thiocyanate AMERICAN ELEMENTS

    Gold(III) Potassium Thiocyanate is generally immediately available in most volumes. High purity, submicron and nanopowder forms may be considered. American Elements produces to many standard grades when applicable, The role of glycine in the ammonium thiocyanate leaching of gold.

    Live Chat