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.[1] Cyanidation is also widely used in the extraction of silver, usually after froth flotation.[2]
Production of reagents for mineral processing to recover gold represents more than 70% of cyanide consumption globally. Other metals are recovered from the process include copper, zinc, and silver, but gold is the main driver of this technology.[1] Due to the highly poisonous nature of cyanide, the process is controversial and its use is even banned in some parts of the world. Cyanide can be safely used in the gold mining industry.[3] A key feature for safe use of cyanide is to ensure adequate pH control at an alkaline pH level above 10.5. At industrial scale, pH control is mainly achieved using lime, as an important enabling reagent in gold processing.[4]
^ abRubo, Andreas; Kellens, Raf; Reddy, Jay; Steier, Norbert; Hasenpusch, Wolfgang (2006). "Alkali Metal Cyanides". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.i01_i01. ISBN 978-3527306732.
^Etris, S. F. (2010). "Silver and Silver Alloys". Kirk-Othmer Encyclopedia of Chemical Technology. pp. 1–43. doi:10.1002/0471238961.1909122205201809.a01.pub3. ISBN 978-0471238966.
^"Cyanide Management" (PDF). Australian Government.
^Du Plessis, C. A.; Lambert, H.; Gärtner, R. S.; Ingram, K.; Slabbert, W.; Eksteen, J. J. (2021). "Lime use in gold processing – A review". Minerals Engineering. 174: 107231. Bibcode:2021MiEng.17407231D. doi:10.1016/j.mineng.2021.107231. S2CID 240128866.
Goldcyanidation (also known as the cyanide process or the MacArthur–Forrest process) is a hydrometallurgical technique for extracting gold from low-grade...
A goldcyanidation ban refers to the legislation that bans mining gold through the goldcyanidation technique. Germany, Czech Republic, Hungary and Costa...
NaCN + H2O2 → NaOCN + H2O Goldcyanidation (also known as the cyanide process) is the dominant technique for extracting gold, much of which is obtained...
in gold mining, organic synthesis, and electroplating. Smaller applications include jewellery for chemical gilding and buffing. Potassium cyanide is highly...
Goldcyanidation is a chemical process for extracting gold from low-grade ore. Used in Romania for decades, the process came into debate following the...
compounds (gold salts) such as gold chloride are toxic to the liver and kidneys. Common cyanide salts of gold such as potassium goldcyanide, used in gold electroplating...
expansion of gold mining to ores that are not on the surface has led to more complex extraction processes such as pit mining and goldcyanidation. In the 20th...
cyanides in effluents from gold mining. The cyanide anion reacts with transition metals to form M-CN bonds. This reaction is the basis of cyanide's toxicity...
extraction technique for recovery of gold which has been liberated into a cyanide solution as part of the goldcyanidation process. Introduced in the early...
wind. Promising to deal with them and to extract remaining gold from them via goldcyanidation, the company shipped its waste product to a dam near Bozânta...
recovery by standard cyanidation and carbon adsorption processes. These refractory ores require pre-treatment in order for cyanidation to be effective in...
environmental toxic waste discharge due to the goldcyanidation technique used in gold mining. Other disasters at gold mines such as those resulting in loss of...
activated carbon, which is the standard technique used in goldcyanidation to separate the gold complex from the ore slurry. However, an electrolytic process...
that is the focus of goldcyanidation, the hydrometallurgical process for winning gold from dilute ores. In fact, sodium cyanide, not the potassium salt...
(died 1920), Scottish inventor of the MacArthur-Forrest process for goldcyanidation (1887) John McArthur (disambiguation) This disambiguation page lists...
in the gold mining industry. It is used for the recovery of fine particles of free gold, meaning gold that does not require goldcyanidation for recovery...
Alkaline goldcyanide, for gold and gold alloy plating Neutral goldcyanide, for high-purity plating Acid gold plating for bright hard gold and gold alloy...
Monte Negro and Moore oxide deposits. The mined ore is processed with goldcyanidation. Pyrite and sphalerite are the main sulfide minerals found in the 120-meter...
leaching of gold and silver. It works with presence of copper as a catalyst here. This process is a nontoxic alternative goldcyanidation. The advantage...
half of the world's gold production by cyanidation at industrial mines is taking place under the conditions laid down by the Cyanide Code. As of January...
of cyanide in commercial goldcyanidation processes. It is used as an SO2 source (mixed with air or oxygen) for the precipitation of elemental gold in...
was stalled in 2021. Anti-mining organisations have attempted to ban goldcyanidation in Romania, because this process has resulted in environmental disasters...
to obtain. Gold readily forms the cyanide complex Au(CN)− 2, which is used in its extraction from ore through the process of goldcyanidation; roentgenium...
CH3COOH Zinc cyanide is also produced as a byproduct of certain gold extraction methods. Procedures to isolate gold from aqueous goldcyanide sometimes call...
closed-shell gold centers. Goldcyanide compounds (MAu(CN)2) are of some importance to goldcyanidation, a process for the extraction of gold from low-grade...
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