sodium thiosulfate gold recovery

Sodium Thiosulphate Gold Leaching

Mar 17, 2017  Sodium Thiosulphate Gold Leaching. 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 ...

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US6632264B2 - Gold recovery from thiosulfate leaching ...

Processes for recovering gold from copper-gold ores thiosulfate leaching or gold ores copper catalyzed thiosulfate leaching using ion exchange technology are disclosed. The processes include subjecting the gold-bearing and copper-bearing thiosulfate solution to a pH and/or temperature adjustment to reduce tetrathionate concentration in the thiosulfate solution prior to contacting with an ion ...

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Thiosulphate Leaching SGS

Thiosulfate leaching offers a number of benefits related to gold recovery yields and environmental concerns: Thiosulfate leaching of gold ores has great potential to reduce the impact on the environment. Unlike cyanide, which is highly toxic, the chemicals used in the thiosulfate leaching process are benign.

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Recovery of Gold from Thiourea, Thiocyanate, or ...

(1991). Recovery of Gold from Thiourea, Thiocyanate, or Thiosulfate Solutions by Reduction-Precipitation with a Stabilized Form of Sodium Borohydride. Separation Science and Technology: Vol. 26, No. 9, pp. 1207-1228.

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Thiosulfate leaching of gold—A review - ScienceDirect

Feb 01, 2001  Thiosulfate is considered a non-toxic alternative to cyanide and can leach gold faster than cyanide. In the conventional cyanide process, the recovery of gold and silver from ores is hindered by a variety of metal impurities like copper, arsenic, antimony, zinc and nickel, since these consume either cyanide or oxygen.

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Thiosulfate leaching of gold—A review - ScienceDirect

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 gold recoveries can be obtained from the thiosulfate leaching of complex and carbonaceous-type ores. In addition, thiosulfate can be cheaper than cyanide.

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COMPARISON OF CYANIDE AND THIOSULPHATE LEACHING

(a) non-refractory or free milling, with over 95% gold recovery, (b) mildly refractory, with 85-95% recovery, (c) moderately refractory, with 50-80% recovery and (d) highly refractory, with under 50% recovery. Research on refractory gold ores has shown that existence of submicroscopic gold particles is the main cause for refractory ores.

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Thiosulfate leaching of gold - A review Request PDF

The ammoniacal thiosulfate leaching process for gold and silver extraction has been reviewed in terms of leaching mechanism, thermodynamics, thiosulfate stability, and gold recovery options.

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GOLD RECOVERY FROM PRINTED CIRCUIT BOARDS OF

gold ores that cannot be treated by the conventional cyanidation process (due to the high cost of reagents and/or low gold recovery) (Senanayake, 2005a; Zhang and Senanayake, 2016). The dissolution of gold with a thiosulfate solution occurs by forming a gold and thiosulfate complex, Au(S 2 O 3) 2 3-. The complex is soluble and very stable

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Gold Sodium Thiosulfate Allergic Contact Dermatitis Database

Check all gold-appearing jewelry for a stamp that indicates the purity (1-999 or .1-.999) or the karat (10K, 14K, 18K, 22K, or 24K). Also avoid all gold-plated jewelry. Inform your healthcare providerss, including dental providers, that you are allergic to gold sodium thiosulfate. Ask

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Effect of additives on thiosulfate leaching of a gold ore

surfactant sodium dodecyl sulfate (SDS) slightly enhanced gold recovery at a lower concentration, but could not stabilise gold thiosulfate in solution. Gold recovery decreased at a higher pH with the addition of ammonia, despite the higher sulfide leaching. This is because the mixed solution potential substantially decreased at a higher pH ...

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Recovery of Gold from Thiourea, Thiocyanate, or ...

(1991). Recovery of Gold from Thiourea, Thiocyanate, or Thiosulfate Solutions by Reduction-Precipitation with a Stabilized Form of Sodium Borohydride. Separation Science and Technology: Vol. 26, No. 9, pp. 1207-1228.

More

GOLD RECOVERY FROM PRINTED CIRCUIT BOARDS OF MOBILE

In the sodium thiosulfate and ammonium thiosulfate tests, it was possible to extract 70 and 75% of the gold contained in the PCB, respectively, using solutions containing 0.12 M of sodium or ammonium thiosulfate, 0.2 M of ammonium and 20 mM of copper sulfate in 4 hours of leaching, at a temperature of 30(2(C and pH 10.

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GOLD RECOVERY FROM PRINTED CIRCUIT BOARDS OF

gold ores that cannot be treated by the conventional cyanidation process (due to the high cost of reagents and/or low gold recovery) (Senanayake, 2005a; Zhang and Senanayake, 2016). The dissolution of gold with a thiosulfate solution occurs by forming a gold and thiosulfate complex, Au(S 2 O 3) 2 3-. The complex is soluble and very stable

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(PDF) A Review of Thiosulfate Leaching of Gold: Focus on ...

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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CA2013537A1 - Recovery of gold from solution by reduction ...

ABSTRACT OF THE DISCLOSURE A process is disclosed for the direct recovery of gold from thiourea, thiocyanate or thiosulfate solutions or acidified thiourea leach liquor. The process comprises reduction precipitation of the gold from solution by the addition of stabilized alkali metal borohydride, preferably sodium or potassium borohydride, at ambient temperature and pressure.

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Common Types of Non-cyanide Gold Recovery Chemicals

Thiourea, thiosulfate, halogens and their compounds, and CNLITE gold recovery chemicals are four common non-cyanide gold recovery chemicals in gold processing plants. They are less harmful to the environment than sodium cyanide and have good development prospects. Actually, there are many non-cyanide gold recovery chemicals such as amino acids ...

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Recovery of gold from solution by reduction-precipitation ...

This invention relates to a process for the recovery of metallic gold from gold-containing thiourea, thiosulfate or thiocyanate solutions. The invention further relates to a process for the recovery of metallic gold generally of high purity from pregnant solutions as a result of the leaching of gold ore or concentrates by acidified thiourea. 2.

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What are the Cyanide-Free Gold Recovery Methods?

The most studied cyanide-free gold recovery methods include water chlorination, bromination and iodination, thiosulfate, thiourea and cyanide substitute gold recovery methods. 1. Water Chlorination Process. The gold leaching chemical reaction equation of this cyanide-free gold recovery method is as follows: 2Au+3Cl2+2HCl→2HauCl4.

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Treatment of a Polysulphide Ore by Ammoniacal Thiosulfate ...

further gold recovery. Gold electrodeposition from ammoniacal thiosulfate solutions, by application of a direct current, presents various hardships. For instance, the presence of cupric ions could contaminate the metallic product obtained by the reduction of gold-thiosulfate complex in the cathode area [1]. Another issue is the high consumption

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Increased Recovery of Gold Thiosulfate Alkaline Solutions ...

Gold recovery curves in gold thiosulfate synthetic solutions (10 mg L 1 Au and 0.1 mol L 1 Na 2 S 2 O 3 ), thioglycolic acid (ATG) stirred in liquid phase (0.001, 0.005, 0.02, and 0.05 mol L 1 ) and carbon concentrations (5, 10, 30, and 50 g L 1 ) at room temperature (15 C).

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The role of ligands and oxidants in thiosulfate leaching ...

The complexity of thiosulfate leaching of gold is exemplified in Figure 1 (14). It shows that sulfite, sulfide, sulfate glycine and ethylenediaminetetracetic acid (EDTA) have beneficial effects on gold extraction, compared to standard thiosulfate leaching with 0.03 M copper sulfate, 0.3 M sodium thiosulfate and 3 M ammonia (pH 10.2) in the

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Gold recovery from refractory gold concentrates by ...

that gold recovery is difficult by thiosulfate leaching without any pre-treatment, and the recovery of gold only is 10.1%. After roasting and oxidizing, the gold leaching rate increases substantially. The leaching rate of gold reaches 71.2% with the optimal leaching technological parameters (Li et al.,

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Gold recovery from thiosulfate leaching - The University ...

In one aspect, the invention provides a process for the recovery of gold from a thiosulfate solution containing polythionates such as tetrathionate with an ion exchange resin. The source of the thiosulfate ion may for example be ammonium thiosulfate, alkali metal thiosulfates such as sodium or potassium sulfate or alkaline earth metal ...

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Recovery of Gold from Thiourea, Thiocyanate, or ...

(1991). Recovery of Gold from Thiourea, Thiocyanate, or Thiosulfate Solutions by Reduction-Precipitation with a Stabilized Form of Sodium Borohydride. Separation Science and Technology: Vol. 26, No. 9, pp. 1207-1228.

More

Gold recovery from refractory gold concentrates by ...

that gold recovery is difficult by thiosulfate leaching without any pre-treatment, and the recovery of gold only is 10.1%. After roasting and oxidizing, the gold leaching rate increases substantially. The leaching rate of gold reaches 71.2% with the optimal leaching technological parameters (Li et al.,

More

Effect of additives on thiosulfate leaching of a gold ore

surfactant sodium dodecyl sulfate (SDS) slightly enhanced gold recovery at a lower concentration, but could not stabilise gold thiosulfate in solution. Gold recovery decreased at a higher pH with the addition of ammonia, despite the higher sulfide leaching. This is because the mixed solution potential substantially decreased at a higher pH ...

More

GOLD RECOVERY FROM PRINTED CIRCUIT BOARDS OF MOBILE

In the sodium thiosulfate and ammonium thiosulfate tests, it was possible to extract 70 and 75% of the gold contained in the PCB, respectively, using solutions containing 0.12 M of sodium or ammonium thiosulfate, 0.2 M of ammonium and 20 mM of copper sulfate in 4 hours of leaching, at a temperature of 30(2(C and pH 10.

More

(PDF) A Review of Thiosulfate Leaching of Gold: Focus on ...

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 ...

More

Increased Recovery of Gold Thiosulfate Alkaline Solutions ...

Gold recovery curves in gold thiosulfate synthetic solutions (10 mg L 1 Au and 0.1 mol L 1 Na 2 S 2 O 3 ), thioglycolic acid (ATG) stirred in liquid phase (0.001, 0.005, 0.02, and 0.05 mol L 1 ) and carbon concentrations (5, 10, 30, and 50 g L 1 ) at room temperature (15 C).

More

Gold recovery from thiosulfate leaching - The University ...

In one aspect, the invention provides a process for the recovery of gold from a thiosulfate solution containing polythionates such as tetrathionate with an ion exchange resin. The source of the thiosulfate ion may for example be ammonium thiosulfate, alkali metal thiosulfates such as sodium or potassium sulfate or alkaline earth metal ...

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The Extraction of Gold from E-waste by Hydrometallurgy ...

As a result, in this research, the possibility of gold transfer from organic phase (DNOS) by 0.5 M sodium thiosulfate was analyzed. To do so, the organic phase of DNOS charged by gold and the aqueous phase of 0.5 M sodium thiosulfate were mixed with a ratio of (A/O) 1:1, 2:1, 4:1, 6:1 and after reaching equilibrium in 15 minutes, they separated.

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What are the Cyanide-Free Gold Recovery Methods?

The most studied cyanide-free gold recovery methods include water chlorination, bromination and iodination, thiosulfate, thiourea and cyanide substitute gold recovery methods. 1. Water Chlorination Process. The gold leaching chemical reaction equation of this cyanide-free gold recovery method is as follows: 2Au+3Cl2+2HCl→2HauCl4.

More

Treatment of a Polysulphide Ore by Ammoniacal Thiosulfate ...

further gold recovery. Gold electrodeposition from ammoniacal thiosulfate solutions, by application of a direct current, presents various hardships. For instance, the presence of cupric ions could contaminate the metallic product obtained by the reduction of gold-thiosulfate complex in the cathode area [1]. Another issue is the high consumption

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Selective Electrochemical Gold Recovery from Leaching ...

May 03, 2017  The electro-recovery of gold from thiosulfate leaching systems was evaluated on Pt electrode using S3 solution with a gold concentration of 0.0014 mol L −1 (27.4 mg of dissolved gold). In Figure 5 the characteristic oxidation Cu/Cu(I)/Cu(II) and reduction Cu(II)/Cu(I)/Cu peaks discussed in the previous results are observed.

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THE INCREASED ACTIVITY IN THE DEVELOPMENT OF

concentration gold thiosulfate solutions (e.g. leaching of gravity concentrates), sulfide precipitation and copper cementation are alternative gold recovery options. However, unlike the resin technology which produces a high grade gold product, sulfide precipitation and copper cementation produce a

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Cyanide-free gold recovery - CSIRO

A commerative gold ingot from the first gold pour using our cyanide-free recovery method. The infrastructure for a processing plant that uses cyanidation typically costs $30 million, and is therefore, a barrier to entry for gold miners with smaller deposits that do not fit into the large-scale economies of gold

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THIOSULFATE LEACHING OF SILVER FROM A SOLID RESIDUE

that the leaching recovery of silver increased with increasing thiosulfate and ammonia concentration. At the highest thiosulfate ions concentration, the observed silver leaching recovery was 60%. The best results were obtained at an ammonia concentration of 0.80 mol/dm3, where the leaching recovery

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