gold cyanidation oxidant

Increase Dissolved Oxygen in Gold Leaching with Hydrogen ...

The dissolution rate drops and the cyanide-accessible gold and silver can not be extracted completely within the conventional leaching time of 48 hours. Hydrogen peroxide has a strong effect on the oxygen concentration of the pulp. The chemistry of this phenomenon is not complicated: H2O2 is a strong oxidant.

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Gold cyanidation - Wikipedia

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 fundamental study of the alkaline sulfide leaching of gold

sulfur containing streams are difficult to treat using cyanidation. In the present paper, the alkaline sulfide system was studied as an alternative to cyanide for recovering gold from elemental sulfur. It was found that the dominant lixiviant for gold in this system is sulfide, and polysulfide was ascertained to be the oxidant.

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Leaching and electrochemistry of gold, silver and gold ...

The leaching and electrochemical behaviour of gold, silver and gold–silver alloys containing 2, 4, 8, 20 and 50 wt.% silver in excess cyanide with various oxidants (air saturated, oxygen saturated, air saturated + Pb, oxygen saturated + Pb and air saturated + 2.5 mM H 2 O 2) have been systematically investigated. It was found that both the ...

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

% gold and silver extraction during thiosulfate leaching and conventional cyanidation of oxide ores (21). In the case of gold ores of low silver grade (0.3 Ag g/t), thiosulfate leaching resulted low gold and silver extraction compared to cyanidation. However, in the case of gold ores with higher silver grades (2.8-15 Ag g/t), silver extraction with

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The novel application of ferricyanide as an oxidant in the ...

Low gold and silver extractions have often been observed in the traditional gold–silver cyanidation process. The reactivity and availability of oxidant is a potential limitation for gold and silver dissolution in cyanide solution, especially in heap leaching operations.

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Gold-catalysed oxyarylation of styrenes and mono- and gem ...

1-Hydroxy-1,2-benziodoxol-3(1H)-one (IBA) is an efficient terminal oxidant for gold-catalysed, three-component oxyarylation reactions. The use of this iodine(III) reagent expands the scope of oxyarylation to include styrenes and gem-disubstituted olefins, substrates that are incompatible with the previously reported Selectfluor-based methodology.

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Thiourea Gold Leaching - Metallurgist & Mineral Processing ...

Another aspect of cyanidation which can be a problem is the somewhat slow kinetics of dissolution of gold by the cyanide species. This can especially be a problem in vat and heap leaching operations which process ores containing fairly large-grained gold particles. The kinetics of thiourea dissolution of gold have been studied extensively.

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The Metallurgy of Cyanide Gold Leaching – An Introduction ...

The Metallurgy of Cyanide Gold Leaching – An Introduction. Leaching gold with a cyanide solution remains the most widely used hydrometallurgical process for the extraction of gold from ores and concentrates. Despite the difficulties and hazards of working with cyanide, no other process has yet been proven to be an economic viable alternative.

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Improvements in gold ore cyanidation by pre-oxidation with ...

Pre-oxidation with H 2 O 2 prior to cyanidation increased DO from 1 up to 7.2 ppm.. H 2 O 2 was injected at a rate of 0.24 kg H 2 O 2 /t of dry ore prior to cyanidation.. NaCN consumption was reduced from 0.52 to 0.40 kg/t.. Au recovery was increased from average 91.3 to 92.5%.

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Gold Cyanidation Using Hydrogen Peroxide

gold extraction are greatly accelerated when using H,O,. Table 1 — Average values of the gold extraction rate by cyanidation of a typical South African ore using HZOZ(adjusted to different 02 levels) and compressed air as oxidants. Gold extraction ratea after Oxidants max. O,-level lh 2h 3h 4h 24h 48h H202 10 ppm 91% 91% 93% 95"/. 95% 95%

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Oxidative leaching of refractory sulphidic gold tailings ...

The effect of temperature in the range of 20–65 °C on gold extraction from refractory gold tailings containing pyrite in 20% (v/v) of 1-butyl-3-methylimidazolium hydrogen sulphate [Bmim + HSO 4 −]-water solution with thiourea as complexing agent and iron(III) sulphate oxidant, at pH of 1 was examined for 12 h leaching time intervals.The experimental results revealed that the extraction of ...

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Leaching Pyrite Gold Ore without Cyanide

NON Cyanide Gold Leaching Tests The leaching experiments were performed with ore that was ground and dried to yield a size distribution with a d80 of 74 µm. Each leaching test was started using 250 g of ore plus 750 cm³ of leaching solution (25% solids by weight) in a 1-liter baffled glass vessel open to the air and at ambient temperature (23 ...

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Gold cyanidation using hydrogen peroxide - ScienceDirect

The influence of pH on the kinetics of gold cyanidation with hydrogen peroxide at atmospheric pressure was determined under the following conditions: 0.01 M NaCN, 0.01 M H 2 O 2, 400 min −1 and 25°C. The corresponding results are shown in Fig. 2.Although the gold dissolution rate decreased with increasing pH, the value of the cyanidation rate at pH 10 (275 μmol m −2 s −1) was …

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THIOSULPHATE LEACHING – AN ALTERNATIVE TO …

CYANIDATION IN GOLD PROCESSING ALTERNATIVES TO CYANIDE IN GOLD PROCESSING THIOSULPHATE LEACHING Thiosulphate leaching is a process that removes gold from gold bearing ores without the use of cyanide. Although not ... oxidant, and ammonium and copper ions as unconsumed catalysts in the reaction.

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Recyclable Treatment of Cyanide in the Mining Industry ...

an oxidant such as oxygen to dissolve gold [6]. During the process of extraction of gold from an aqueous cyanide solution it forms a gold cyanide complex by oxidizing the oxidant and cyanide complexation. There are alternative complexing reagents for gold mining such as Chloride, Bromide, Thiourea and Thiosulphate. These complexants form less ...

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Effects of Potassium Nitrate (Sa ltpetre) On Gold Cyanidation*

cyanidation process. The cyanidation test was conducted on a free milling, oxide gold ore. The outcome of the leaching test showed that saltpetre could be used as an oxidant for gold cyanidation. After using saltpetre as an oxidant in cyanide

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Gold processing - Mining and concentrating | Britannica

In cyanidation, metallic gold is oxidized and dissolved in an alkaline cyanide solution. The oxidant employed is atmospheric oxygen, which, in the presence of an aqueous solution of sodium cyanide, causes the dissolution of gold and the formation of sodium cyanoaurite and sodium hydroxide, according to the so-called Elsner reaction:

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5 Intensified Cyanide Leaching Methods You Need to Know

Cyanide gold leaching is a process of extracting gold with cyanide as the leaching reagent, which is the most important gold extraction method because of its mature process, high recovery rate, low cost, etc.However, there are still some aspects to be improved, such as improving the cyanide gold extraction process, shortening the cyanide leaching time, decreasing the cyanide …

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GOLD RECOVERY OF REFRACTORY SULFIDE CONCENTRATES …

reagent on cyanidation of refractory gold ore. Cyanide leaching of the concentrate was performed at 20%-w/w of solid (500 gram of refractory sulfide gold ore concentrate) in a 2.5-liter glass reactor with aeration and stirred at 250 rpm. Leach solutions were prepared using deionized-distilled water at the prescribed concentration of reagents.

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CHLORIDE HYPOCHLORITE OXIDATION AND LEACHING OF …

in Table 1. As shown in this table, by flotation of the ore with 3.770 g/Mg gold, a con-centrate containing 20.451 g/Mg gold was obtained. After 24 hours, direct cyanide leaching of the initial ore resulted in only 54.8% gold recovery. However, cyanidation after dissolving the ore sample in hydrochloric acid (HCl), sulfuric acid (H 2 SO 4

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GOLD RECOVERY OF REFRACTORY SULFIDE CONCENTRATES …

The problem of refractory sulfide gold ore that has a gold recovery less than 50% when direct cyanidation applied, still exists until now. It needs oxidative pretreatment for cyanidation to be effective in gold recovery the objective of this study is figuring out the effect of sodium nitrite as an oxidizing reagent on cyanidation of refractory gold ore.

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Gold Leaching Using Thiourea from Uranium Tailing Material ...

The cost of cyanide and thiourea per kilogram is roughly equal, but thiourea leaching is more suitable for the treatment of refractory sulfide gold ores, and it has a much lower toxicity and faster for gold leaching with an appropriate oxidant reagent when compared with cyanide [13, 14]. Gold leaching in acidic thiourea solutions avoids the ...

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Demonstration of the CESL Gold Process - Teck Resources

Process and uses pressure cyanidation to increase the kinetics of gold and silver leaching, as well as cyanide recovery to recover copper and reduce cyanide consumption, allowing for ... oxygen serves as an oxidant and cyanide as a complexing agent. The cyanide gold dissolution reaction is described by Elsner's Eq. (Marsden & House, 2006):

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The role of ligands and oxidants in ... - Gold Bulletin

The widely used cyanidation technology is not applicable to some gold ores due to economic or technical reasons when the cyanidation gives very low gold extractions. Despite the fact that the gold mining industry accounts for only 13% of total cyanide consumption there is growing public concern over the use of toxic cyanide for gold extraction. Many researchers have identified that thiosulfate ...

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Use of ferricyanide for gold and silver cyanidation ...

The use of ferricyanide as the auxiliary oxidant for gold and silver cyanidation has been examined. The rotating disc test results prove the assistant effect of ferricyanide on increasing the dissolution rate of gold and silver. The potential use of ferricyanide in gold/silver cyanidation process is proposed based on the leaching results of ...

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Gold Leaching Agent Compared to Cyanide in Gold Processing

Cyanide leaching is a process in which solid natural gold in ore or beneficiation product forms a gold-cyanide complex dissolved in water under the combined action of a leaching agent, an oxidizing agent and a base, that is, a phase transformation process of solid phase gold. Chemical reaction formula for gold leaching: 4Au+8KCN+2H2O→4KAu (CN ...

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Effect of Oxygen on Gold Leaching

The rate of dissolution of gold in alkaline cyanide solution is dependent on a number of factors, principally the solution composition (pH, complexant concentration), the redox potential (oxidant concentration), the surface area of the gold, temperature and mass transport rates (mixing).

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(PDF) Gold recovery of refractory sulfide concentrates ...

PDF | On Dec 11, 2017, Suratman Suratman published Gold recovery of refractory sulfide concentrates using direct cyanide leaching with nitrite as an oxidant …

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Technical Note Cyanidation of Turkish gold-silver ore and ...

1990). In 1987, the first economically successful application of pure oxygen as an oxidant in the cyanidation of gold ores took place at the South African Fairview Mine. Since the pure oxygen technology is very similar to the aeration with compressed air, in the case of viscous and strong oxygen-consuming pulps,

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Cyanide and Other Lixiviant Leaching Systems for Gold with ...

All systems require an oxidant to oxidise gold and a ligand to complex with gold in solution. Adjustment of pH is usually necessary. Alkaline lixiviant systems (pH > 10)include cyanide, ammonia-cyanide, ammonia, sulphide, nitriles, and a few other minor possibilities. Oxygen is the main oxidant.

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The novel application of ferricyanide as an oxidant in the ...

Low gold and silver extractions have often been observed in the traditional gold–silver cyanidation process. The reactivity and availability of oxidant is a potential limitation for gold and ...

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(PDF) Cyanidation of Turkish gold-silver ore and the use ...

The leaching and electrochemistry of gold, silver and gold–silver alloys in cyanide solutions has been investigated using air, oxygen and/or hydrogen peroxide as oxidant in the presence or ...

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The process design of gold leaching and carbon-in-pulp ...

African gold plant. These figures are not a standard but reflect the nature of the ore and the design basis for a particular situation. The ore is first reduced in size (typically 80% passing 75µm) to ensure that all non-refractory gold is readily accessible for cyanide leaching. There are several variations of comminution circuits used in the ...

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Hydrogen Peroxide in CIL Gold Leaching Circuit ...

Using H2O2 as an oxidant, the gold concentration in solution does not drop again, if the leaching process is continued up to 48 hours. The data from our leaching tests show that hydrogen peroxide is not a "magic chemical" in cyanidation. Only the cyanide-accessible-gold can be extracted, but the extraction kinetics are significantly accelerated.

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Co-intensification of cyanide leaching gold by mercury ...

email protected] DOI: 10.1016/S1003-6326(09)60332-0 LI Qian, et al/Trans. Nonferrous Met. Soc. China 20(2010) 1521−1526 1522 cyanide leaching gold by mercury ions and oxidant were studied. 2 Experimental Sodium cyanide, mercury nitrate, peroxide, oxygen and sodium hydroxide are of analytical grade and doubly distilled water, filtered through a Millipore Milli-Q system, was used in all ...

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