Gold dissolution and precipitation depend on the environment's pH and Eh. Hydrogen peroxide intensifies the process in alkaline environments. 18 Although cyanidation has been widely used as a method for leaching free-milling and complex gold ore samples, it has become increasingly important to identify alternative solvents to cyanide for detoxification and …
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Hydrogen peroxide is known to the mining industry as a powerful oxidant, able to attack and to destroy cyanide, the most important leaching reagent (Knorre and Griffiths, 1984; ... Dlssolutlon of Gold m Cyanide Solutions," Journal of Metals, Vol. 6, pp 5t -58, Warstell, J 1987, 'Enhance Heap Leaching Rates with Ar InjectIon Into the Heap ...
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For example, Barrick Gold Co. — one of the largest gold mining companies in the world — was required to invest a surplus of nearly $500 million in 2018 to compensate for 3 cyanide spills in 3 ...
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The purpose of this briefing is to provide a general overview about the use of cyanide and its application to recover gold from ore. While the use of cyanide is essential to the modern gold mining industry, SME acknowledges the public's concern regarding the use of this reagent and through this discussion presents information to inform and engage in meaningful dialogue …
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This study assessed the effectiveness of the current cyanide management practice of a large gold mine as a case study of Thailand's cyanide-contaminated mine waste management policy. Most gold mines worldwide use cyanide to extract gold from ore, and various cyanide compounds, including hydrogen cyanide (HCN), are then discharged into a tailing storage …
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Hydrogen cyanide vapour has been used to fumigate buildings and ships, to exterminate rabbits, rodents, and large predators, and in horticultural practice to control insect pests that have developed resistance to other pesticides …
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Cyanide compounds are used in a number of industrial processes including mining, electroplating, metallurgy, chemical manufacturing, and photography because these compounds can form stable complexes with a range of metals. Hydrogen cyanide is also a component of tobacco smoke, vehicle exhaust, and is produced by the burning of some plastics.
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Gold cyanidation (also known as the cyanide process or the MacArthur–Forrest process) is a hydrometallurgical technique for extracting gold from low-grade ore through conversion to a water-soluble coordination complex.It is the most commonly used leaching process for gold extraction. [1] Cyanidation is also widely used silver in extraction, usually after froth flotation.
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The findings provide the basis to optimize the decomposition of cyanide from gold leaching tailings in mining or backfilling by using the synergetic effect of Na2S2O5 and H2O2.
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This paper reviews the basic chemistry of cyanide, methods by which cyanide can be analyzed, and aspects of cyanide behavior that are most relevant to environmental …
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Gold is a highly required material for a wide range of personal and industrial applications. The high demand for gold, together with the shortage of natural resources and high pollution potential of wastes generated during mining and ore processing activities led to search for alternative sources of gold. A possible source is represented by mine wastes resulting from …
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Air samples were collected at a distance of 0.1, 1.0 and 2.0 km away from the gold mine. All cyanide compounds were extracted using 75 μm carbowax/polydimethylsiloxane-coated SPME fibre and ...
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Hydrogen cyanide is easily soluble in water and produces cyanide ions, which can form hydrogen cyanide. ... J., Chen, P., et al. Determination and detoxification of cyanide in gold mine tailings ...
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The dissociation (ionisation) constant of hydrogen cyanide, pKa(HCN), has been measured by high precision glass electrode potentiometric titrations in saline solutions containing up to 5 mol/L sodium chloride. The dissociation constant of water that is necessary for the calculation of pKa(HCN) has also been measured. In saline solution, and in contrast to …
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This study assessed the effectiveness of the current cyanide management practice of a large gold mine as a case study of Thailand's cyanide-contaminated mine waste …
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Semantic Scholar extracted view of "Design of an automated cyanide gas detection and control system for a gold mine" by Brian A. Shumba et al. Skip to search form Skip to main ... green, blue (RGB) color sensor was developed for detecting low ppm concentrations of hydrogen cyanide gas and could provide the first real time respirator end-of ...
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Similarly, cyanide residues produced in gold mining operations could be used for new extraction processes, presenting an economically viable alternative for purchasing cyanide for gold mines ...
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Cyanide leaching is the predominant process of gold extraction in large scale mining. Current initiatives for reducing the use of mercury in small scale and artisanal mining tend towards the cyanide technology as the only feasible alternative. Thus, the deliberate handling in consideration of the hazardous nature of cyanide compounds is an issue of particular importance.
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1. Introduction. Cyanide leaching (cyanidation), which converts the gold into a cyanide complex (Au(CN) 2 −) that is soluble in water, is currently the most prevailing and effective process to extract gold from ores [1, 2].This process requires excess cyanide to improve gold recovery and produces exceptionally large quantities of cyanide-bearing wastes in the …
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Although the use of cyanide is mostly perceived by the general public as being associated with the mining and metallurgical processes, only about 13% of world cyanide production is consumed by these industries with the remaining percentage being used elsewhere (WHO ECEH, 2000, Mudder and Botz, 2001, Mudder et al., 2001a, Mudder et al., 2001b, Akcil, …
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hydrogen cyanide gas; underground mining 1. Introduction The issue of cyanide contamination within mining backfill has been recently highlighted by Reichardi [1] . Although the mining industry only accounts for 15% of global cyanide consumption, the gold mining industry is under scrutiny from both regulators and the society at large.
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The Cyanide Code. The "International Cyanide Management Code For the Manufacture, Transport, and Use of Cyanide In the Production of Gold" (Cyanide Code) is a voluntary, performance driven, certification program of best practices for the management of cyanide in gold and silver mining. Participation is open to gold and silver mining companies, manufacturers of …
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Cyanide is a highly toxic chemical produced in large amounts by the mining and jewellery industries, steel manufacturing, coal coking, food processing and chemical synthesis (Luque‐Almagro et al, 2011).The mining industry uses so‐called cyanide leaching to extract gold and other precious metals from ores, which leaves large amounts of cyanide‐containing liquid …
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Of the 1.1 million tons of hydrogen cyanide (HCN) produced annually, only 6% is converted into sodium cyanide for use in the mining industry. ... Nevada is the hub of the U.S. gold mining industry, accounting for the most exploration and mining activity on federal lands. The State of Nevada alone annually contributes approximately 75% to ...
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Sodium cyanide (NaCN; CAS RN 143-33-9) is used mainly as an extraction agent for precious metals (for example, gold, silver) and to a lesser degree for base metals, and as a result, free cyanide and precursors of free cyanide may be released in …
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gas, such as hydrogen cyanide (HCN) or a crystal form such as sodium cyanide (NaCN). When present in air, it is usually in the form of HCN gas. ... cyanide management from manufacture to transport and use in gold mining. The Code defines a series of principles and objectives to improve cyanide management and thereby reduce risks to workers, the
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detoxification of cyanide from the tailing effluent of Muteh gold mine in Isfahan, Iran. In this research cyanide detoxification was achieved through the oxidation of cyanide by hydrogen peroxide using various hydrogen peroxide solutions at pH levels between 7-13 and temperatures between 12-65 °C using copper sulfate as a catalyst.
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The term "cyanide" refers to a chemical compound containing one atom of carbon and one atom of nitrogen. The technical definition of cyanide is a triple-bonded molecule with a negative one charge, consisting of one atom of carbon in the +2 oxidation state and one atom of nitrogen in the −3 oxidation state (InfoMine, 2012).Cyanides most commonly refer to salts of …
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1.. IntroductionGold and silver recovery by cyanidation is widely used in mining operations. Other industrial applications of cyanide include metal processing, electroplating, steel hardening, photographic applications, and synthetic rubber production (Habashi, 1987; Mudder, 2001; Mudder et al., 2001a; Botz and Mudder, 2002; Akcil, 2003a).Although gold mining …
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Activated carbon, with its extensive network of pores, acts as an adsorbent. In gold mining, it traps gold cyanide complexes (Au (C N) 2 −)formed by leaching gold ore with cyanide solution (NaCN) . This adsorption process is primarily physical, involving weak attractive forces between the gold complex and the carbon surface .
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cyanide (NaCN) are used in gold mining operations, typically in the range of 0.01% to 0.05% cyanide (100 to 500 parts per million [ppm]) for the process of leaching (Logs-don, Hagelstein, …
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Soto-Uribe et al. [8] reported the extraction of 95% gold from gold ore using sodium cyanide, while Wu et al. [69] found that over 85% of gold was extracted from copper-gold concentrate using ...
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This present article reviews the determination and detoxification of cyanide found in gold mine tailings. Most of the cyanide remains in the solution or the slurries after the cyanidation process. ... Safavi A, Maleki N, Shahbaazi HR (2004) Indirect determination of cyanide ion and hydrogen cyanide by adsorptive stripping voltammetry at a ...
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This data-file captures the cost of producing cyanide — hydrogen cyanide as a chemical intermediate and sodium cyanide as a crucial input to the gold-silver mining industry. Marginal costs are estimated at $1,500/ton and $1,650/ton respectively, in normal times.
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Hydrogen cyanide (HCN) is commonly released into the atmosphere from vehicle emissions, biomass burning and industrial processes such as gold mining, pesticide production, and chemical manufacturing.
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Cyanide leaching is the predominant process of gold extraction in large scale mining. Current initiatives for reducing the use of mercury in small scale and artisanal mining …
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