leaching gold ore thiosulphate

Treatment of copper-rich gold ore by cyanide leaching ...

sulphide minerals during cyanidation of gold [13,14,16]. Preleaching of ore can be undertaken to remove reactive copper minerals prior to cyanide leaching of gold. SCERESINI and STAUNTON [17] proposed the removal of copper by cyanide leaching without aeration prior to gold extraction and then adsorption of copper on activated carbon.

The deportment of mercury during thiosulfate leaching and ...

 · This paper reports on the behavior of mercury and its compounds during the thiosulfate leaching and recovery of gold. Thiosulfate solutions are shown to dissolve Hg0 and Hg2Cl2 to a similar extent as cyanide, but the leaching of HgS is significantly slower in thiosulfate solutions compared to cyanide. Hence, the use of thiosulfate may be an option for treating ores containing high levels of ...

In place leaching of oxidized gold deposits. A new method ...

leaching of gold ores. This work also indicated that the presence of pyrite results in rapid catalysed oxidation of the sodium thiosulphate rendered the method ineffective in the absence of a method for passivating the pyrite prior to lixiviant introduction and throughout the leaching process. Therefore, this research has focused on gold ore ...

Improvement of thiosulfate stability in gold leaching ...

 · 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. In the testing, thiosulfate consumption was 30 kg/t of ore.

Thiosulphate as an alternative to cyanide for gold ...

 · Thiosulphate is an attractive alternative reagent to cyanide for processing gold ores. It is relatively cheap and non-toxic, forms relatively strong gold and silver complexes, and readily leaches gold ores in ammoniacal solutions, catalysed by Cu(II). It is particularly suited to carbonaceous ores where the recovery of gold by cyanide is poor.

IN-FIELD TESTING AND VALIDATION OF THIOSULPHATE: A ...

recovery of leachable gold, taking into account the economics of longer leach residency time vs. diminishing gold recovery returns. This KPI in particular has been met with resounding success—the thiosulphate leaching solution led to an . 85% gold recovery rate. Note: This project was initiated using vat leaching tanks in the process.

(PDF) Ammoniacal thiosulfate leaching of gold from a ...

Ammoniacal thiosulfate leaching of gold from a refractory ore using a full factorial design. ibrahim alp. Ersin Yazici. Haci Deveci. ibrahim alp. Ersin Yazici. Haci Deveci. Download PDF. Download Full PDF Package. This paper. A short summary of this paper. 37 Full PDFs related to this paper.

EXTRACTION OF GOLD AND SILVER FROM TURKISH GOLD ORE …

 · Thiosulphate leaching of precious metals is one of the processes that were developed as an alternative and nontoxic technique to conventional cyanidation. The aim of this experimental study was to investigate the possibilities of leaching gold and silver in ammoniacal thiosulphate solutions on a laboratory scale.

Leaching of Ovacık gold ore with cyanide, thiourea and ...

 · Thiourea leaching of Ovacık ore was found to be technically possible with slightly better extraction rates. Dissolution rates were also faster than cyanidation and thiosulphate leaching. However, relatively high consumptions of thiourea and thiosulphate turn these processes into an expensive operation compared to cyanidation.

Method for thiosulfate leaching of precious metal ...

Hemmati, M. et al.; "Study of the Thiosulphate Leaching of Gold from Carbonaceous Ore and the Quantitative Determination of Thiosulphate in the Leached Solutions," Papers presented at the Extraction ''89 symposium, organized by The Institution of Mining and Metallurgy and held in London, from Jul. 10-13, 1989, pp. 665-678.

How to Use Bleach on Gold Ore to Remove Gold | Sciencing

 · This was the first commercial method used for gold extraction. Place the ore into the mortar and grind it to the size of sand grains. Put the ore grains into a plastic bowl. Add the 35-percent hydrochloric acid to the sodium hypochlorite bleach into a flask or beaker, in a two-to-one ratio of acid to bleach. Ensure that the liquid mixture is at ...

The treatment of copper–gold ores by ammonium thiosulfate ...

 · The research was conducted on low-grade oxidized gold ores with application to heap, dump or in situ leaching techniques. The range of the thiosulfate concentration tested was 0.05–0.2 M. After leaching for 48 h, 83% gold extraction was achieved with 0.2 M S 2 O 3 2− with 0.4 kg S 2 O 3 2− consumed per ton of ore.

CN103409623A

The invention provides a method for reducing consumption of thiosulfate in a gold leaching system. According to the method, the additive is humic acid extracted from coal and adopting fulvic acid, and humin acid as main components; during application, the humic acid is added into a copper-ammonia-thiosulfate system, wherein the adding amount of the humic acid is in the range of 20-120 mg/dm3 ...

Gold strike with thiosulphate

 · Thiosulphate has long been seen as a potential alternative to cyanide for liberating gold from ores, but until now it has proved difficult to master. Cyanide is highly toxic and an environmental ...

Conference Proceeding: AMMONIACAL THIOSULPHATE LEACHING …

Keywords: Leach, thiosulphate, copper-gold ore, gold, Taguchi design (received 31 March 2011, accepted 2 May 2011) Introduction Cyanide is the most preferable leaching agent since it forms strong complexes with gold. Due to high toxicity of cyanide and, hence, stringent environmental regulations, there has been growing interest on alternative ...

Oxidative pre-treatment in thiosulphate leaching of ...

 · The acid wash did not dissolve any gold showing that no adsorbed gold complexes were present on the mineral surfaces in the sulphide ore. A gold recovery of 91% was achieved in the direct ammoniacal thiosulphate leaching with 0.25 M thiosulphate, 1 M ammonia and 12 mM cupric ions after 24 h, and gold extraction was obtained at doubled ammonia and thiosulphate …

GOLD EXTRACTION FROM A COPPER BEARING ORE BY …

the copper bearing gold ore. 2. Pre-leaching of the Ore: The copper bearing ore sample has been pre-leached with NH4OH solution for 6 hours, followed by adding thiosulphate. The gold extraction results of pre-leaching has demonstrated that there were no differences between

(PDF) Thiosulphate leaching for gold hydrometallurgy ...

The pH of the pulp ranged from 8.5 to 10.5.Adsorption studies were carried out with the actual ammoniacal thiosulphate solution coming from the leaching of the gold ore sample. The gold concentration of the solution was in the range from 2 mg/l to 16.60 mg/1 and the pH was 10.5.

COMPARISON OF CYANIDE AND THIOSULPHATE LEACHING …

Thiosulphate leaching can be considered as a non-toxic process. It has its own pros and cons which have been discussed in this work. The topics of this work are gold ores and their suitability for leaching processes, pretreatment of concentrate, leaching chemistry and

Thiosulphate Stability In Gold Leaching Process

Ammonium thiosulphate is an alternative gold leaching Laaviant used to replace cyanide. The current problem of thiosulphate gold leaching is the high reagent consumption, To understand the decomposition chemistry of thiosulphate, solution stability tests were conducted in open and sealed vessek mder ambient temperature

Sodium Thiosulphate Gold Leaching

 · 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 ...

Recent Advances in the Development of an Alternative to ...

Thiosulphate leaching of gold (and silver) ores has been studied by many . researchers over the years and there is an extensive literature on the subject. Some recent examples are the papers by Tozawa et al., 1981, Langhans et al., 1992 and Li et al., 1995. The chemistry is complex, involving thiosulphate, ammonium and copper ions, with

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

Gold extraction was found to be enhanced with solutions containing 15-20. mM cupric, 0.1-0.14. M thiosulfate, and 0.2-0.3. M ammonia. Similar trends were obtained for the leaching of gold from two different types of scraps and PCBs of waste mobile phones.

Thiosulphate Leaching | SGS

Thiosulphate Leaching. Thiosulfate leaching is a process that recovers gold from ore without the use of cyanide. SGS developed the thiosulfate leaching process because in some jurisdictions, increased regulation pressure means that cyanide cannot be used or transported. We are a global technical leader in the field of thiosulfate leaching.

The Effects of Common Associated Sulfide Minerals on ...

D. Feng, "Preg-robbing phenomena in the thiosulphate leaching of gold ores," Minerals Engineering, 14 (2001), 1387–1402. CrossRef Google Scholar. 12. P.L. Breuer and M.I. Jeffrey, "The reduction of copper(II) and the oxidation of thiosulphate and oxy-sulphur anions in gold leaching solutions," Hydrometallurgy, 70 (2003), 163–173.

WO2005017215A1

An improved thiosulphate leach process for the recovery of gold from ores and other gold-bearing materials, characterised in that the leach solution comprises thiosulphate, thiourea or a reagent chemically related thereto, and an oxidant that does not oxidise thiosulphate, the process producing a pregnant leach solution from which gold may be recovered.

THIOSULPHATE LEACHING – AN ALTERNATIVE TO …

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 ...

Thiosulphate leaching for gold hydrometallurgy | Semantic ...

Ammoniacal thiosulphate solution allows the solubilization of gold as stable anionic complex. Leaching of gold occurs at appreciable dissolution rates. The aim of this work is devoted to a preliminary evaluation of the feasibility of thiosulphate leaching for the extraction of gold from precious metals ores on a laboratory scale.

L.R. Freitas, R.B.E. Trindade and T. Carageorgos

reagents investigated for gold leaching, thiosulphate seems to he one of lhe most prorrúsing for copper-gold ores. Contrary to cyanide, the process using thiosulphate actually needs some copper present in the ore; olherwise the gold dissolution is not possible. The present work presents basic facts about the chcmistry and

A study of thiosulfate leaching of gold from carbonaceous ...

A comparison of thiosulfate with cyanide leaching of gold from carbonaceous ore showed that thiosulfate is chemically better and economically more advantageous. Description. Online access for this thesis was created in part with support from the Institute of Museum and Library Services (IMLS) administered by the Nevada State Library, Archives ...

Associated Sulfide Minerals in Thiosulfate Leaching of ...

The effects of some associated minerals on thiosulfate gold leaching were studied through thermodynamic analysis and leaching experiments on composite ore samples containing various minerals and a reference silicate gold ore. In the leaching test on the reference gold ore, about 93% of gold was extracted within 3.0 hours.

COMPARISON OF CYANIDE AND THIOSULPHATE LEACHING FOR GOLD …

Corpus ID: 29977655. COMPARISON OF CYANIDE AND THIOSULPHATE LEACHING FOR GOLD PRODUCTION ( A Literature Review ) @inproceedings{Gradov2013COMPARISONOC, title={COMPARISON OF CYANIDE AND THIOSULPHATE LEACHING FOR GOLD PRODUCTION ( A Literature Review )}, author={D. Gradov}, year={2013} }

Ammoniacal thiosulphate leaching of gold ore

The ammoniacal thiosulphate leaching of two gold ore samples namely Akeshi and Hishikari was carried out as a function of time and the results are given in Figure 1a. In this experiment, the thiosulphate and ammonia concentrations were kept at 0.5 and 1M respectively. The solid concentrations of the ores were

sketches & tables

1.4 Leaching processes 3 1.5 Gold extraction processes 4 1.6 Cyanide leaching vs. thio-compound leaching 5 2. Microscopy of gold ores and treatment products 5 2.1 Tasks and problems of microscopical investigations 5 2.2 Microscopy of selected gold ores …

Gold dissolution in non-ammoniacal thiosulphate solutions ...

alternative to cyanidation for treating some sulphidic gold ores. Keywords: Thiosulphate, gold oxidation, leaching, electrochemistry, kinetics. Introduction Concern about the environmental impact of the widely used cyanidation technology has generated a lot of interest in searching for an alternative process for gold leaching over the past years.