gold cyanidation oxidant

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

Leaching reagents in the form of cyanide and an oxidant such as air or oxygen are added after thickening. Leaching ... value of around 9.5–11 to ensure minimum loss of cyanide as hydrogen cyanide. The leaching of gold can be conveniently represented by the Elsener equation: [1] ... The process design of gold leaching and carbon-in-pulp circuits

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

Dec 01, 2008· The novel application of ferricyanide as an oxidant in the cyanidation of gold and silver Xie, Feng; Dreisinger, David; Lu, Jianming 2008-12-01 00:00:00 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 ...

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.

CHLORIDE HYPOCHLORITE OXIDATION AND LEACHING OF …

(with 200 g/dm3 concentrate, stirring speed 600 rpm and temperature 25 C) at which about 82% gold was extracted in 2 h. Keywords: refractory gold ore, oxidative pre–treatment, non–cyanide leaching Introduction Although cyanide has been used commercially for the extraction of gold, investiga-

Gold cyanidation with potassium persulfate in ... - DeepDyve

Jan 01, 2000· Abstract. The use of potassium persulfate as oxidant in gold cyanidation is proposed at pH values between 10 and 11. The addition of thallium (I) ions enables high cyanidation rates to be maintained at pH values higher than 11, as it acts as a catalyst of the process.

Use of ferricyanide for gold and silver cyanidation

low solubility of oxygen in cyanide solution, the reactivity and availability of oxidant is believed to be the critical limitation for gold and silver dissolution. The use of ferricyanide as the auxiliary oxidant for gold and silver cyanidation has been examined. The

Alternative lixiviants to cyanide for leaching gold ores ...

Alternative lixiviants to cyanide for leaching gold ores M.G. Aylmore Placer Dome Technical Services Ltd., 323 Alexander St., Vancouver, BC, Canada V6A 1C4 Over 25 alternative lixiviant processes to cyanide have been tested in the laboratory, some of which have been successful for niche applications.

(PDF) Co-intensification of cyanide leaching gold by ...

Co-intensification of cyanide leaching gold by mercury ions and oxidant LI Qian( ), JIANG Tao( ), YANG Yong-bin(), LI Guang-hui(), GUO Yu-feng(), QIU Guan-zhou() School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China Received 6 July 2009; accepted 4 January 2010 Abstract:The effects of mercury ions ...

DISSOLUTION OF GOLD WITH CYANIDE REPLACING REAGENTS

dissolution rate determined for cyanide solution was 2.5 mg cm-2 h-1. Based on polarisation experiments and potential measurements, the ammonium thiosulfate system with cupric ion as oxidant was estimated to dissolve gold slower than cyanide. In the QCM tests the chloride-hypochlorite alternative showed

Gold processing - Mining and concentrating | Britannica.com

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:

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.

A Method for Leaching or Dissolving Gold from Ores or ...

native gold from gold-bearing ores or ... in the presence of both a strong oxidant and a halide anion under highly acidic solutions. Moreover, a hot solution of hydrochloric acid mixed with a hydro- ... metallurgical leaching of gold ores by cyanidation or in the aqua regia process

GOLD RECOVERY OF REFRACTORY SULFIDE CONCENTRATES …

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. Cyanide leaching of the concentrate was performed at

Optimisation of Operating Parameters for Cyanidation of ...

Optimisation of Operating Parameters for Cyanidation of Sulide-Bearing Gold Flotation Tailings in order to Prevent the Impact of Cyanicides E Ghasemian Langeroudi1, B Levasseur2, F Saizadeh3, C olsen4, F Larachi5 and C Gagnon6 ABSTRACT Gold recovery by the cyanidation process is often accompanied by the leaching of other species.

Gold By Cyanidation Leaching Tank - Blogger

Gold is one of the noble metals and as such it is not soluble in water. A complexant, such as cyanide, which stabilizes the gold species in solution, and an oxidant such as oxygen are required to dissolve gold. The amount of cyanide in solution required for …

Leaching Gold-Silver Ores With Sodium Cyanide and Thiourea ...

with gold solubilized as a cationic complex. Cyanide extracts gold in an alkaline medium, and although no oxidant other than air from agitation is generally applied, addition of an oxidant may be beneficial (4). The dissolution of gold by cyanide iy expressed by with gold solubilized as an anionic complex. EXPERIMENTAL

Assisted leaching using peroxide | nowata - nowatafrica.com

In heap leach operations the oxidant is usually the air present in the heap. In any cyanidation process it is crucial to have both cyanide and an oxidant, in the conditions prevalent in most cyanide plants the rate of gold extraction is controlled by the dissolved oxygen content of the pulp.

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.

Technical Note – Development in gold leaching using ...

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%

Gold Leaching - CAIRE Inc.

The use of oxygen compounds instead of air as an oxidant increases the leach rate and decreases cyanide consumption. This increase in the dissolved oxygen level of gold bearing slurry enhances the gold cyanidation process, thereby increasing gold recovery rates. Cyanide is the second highest operating cost behind electric power for the ore ...

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.

GRAVITY LEACHING – THE ACACIA REACTOR

ACACIA Reactor. Five oxidants were reviewed including air, oxygen, perborate, hydrogen peroxide and a chemical oxidant (Staunton and Nicol, 1999). The test work indicated that there were two preferred oxidants, hydrogen peroxide and the chemical oxidant. To date the chemical oxidant preferred by ConSep is LeachAid.

Gold cyanidation with potassium persulfate in the presence ...

The use of potassium persulfate as oxidant in gold cyanidation is proposed at pH values between 10 and 11. The addition of thallium (I) ions enables high cyanidation rates to be maintained at pH values higher than 11, as it acts as a catalyst of the process.

Cyanide - Wikipedia

A cyanide is a chemical compound that contains the group C≡N. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom.. In inorganic cyanides, the cyanide group is present as the anion CN −. Salts such as sodium cyanide and potassium cyanide are highly toxic. Hydrocyanic acid, also known as hydrogen cyanide, or HCN, is a highly volatile liquid that ...

Comparative study of auxiliary oxidants in cyanidation of ...

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 ...

Use in Mining | International Cyanide Management Code ...

Gold and silver are not soluble in water. A complexant, such as cyanide, which stabilizes the gold and/or silver species in solution, and an oxidant such as oxygen are required to dissolve these metals.The amount of cyanide in solution required for dissolution may be …

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

The role of ligands and oxidants in thiosulfate leaching of gold Gamini Senanayake A.J. Parker Cooperative Research Centre for Hydrometallurgy, Department of Mineral Science and Extractive Metallurgy, Murdoch University, Perth, WA 6150, Australia Abstract The widely used cyanidation technology is not applicable to some gold ores due to economic or

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

showed that saltpetre could be used as an oxidant for gold cyanidation. After using saltpetre as an oxidant in cyanide leaching, Au recovery of approximately 99% was realised whiles approximately 98% recovery was obtained from cyanide leaching involving hydrogen peroxide and atmospheric air as oxidants.

Cyanide process | metallurgy | Britannica.com

More gold is recovered by cyanidation than by any other process. 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…

Comparative study of auxiliary oxidants in the cyanidation ...

It could be concluded that with enough lead in the leaching system the presence of sufficient oxidant could further enhance cyanidation of acanthite. Noticeably lower extraction of silver than gold in conventional cyanidation process has been commonly observed. Acanthite (Ag₂S) is one of the typical silver minerals with low solubility in ...

Use of ferricyanide for gold and silver cyanidation | F ...

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 ...

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.

Agitation Leaching Theory And Practice Biology Essay

Complexes, like cyanide, is known for stabilizing the gold species in solution, along with an oxidant preferably oxygen thereby dissolving the required amount of gold. The amount of cyanide in solution required for complete dissolution may be typically of very low concentrations such as 350 mg/l which accounts for around 0.035% of sodium ...