• Cyanide control in the metallurgical process of gold ...

    Elsner''s reaction gives the required molar ratio of free cyanide to oxygen as 8:1 (or 61/ 2:1 when expressed as a mass ratio). Since cyanide is the more expensive reagent, it is desirable from a financial point of view to ensure that cyanide is the rate-limiting reagent. Hence a cyanide-to-

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  • Cyanide Processing Equipment and Plant Configuration Options

     · The sand fraction is given an agitation of about four hours, resulting in small agitators, and on account of the fast settling characteristics of the sand, thickeners with a capacity of about 0.3 sq. ft. per ton are successfully operated. Accordingly a very small, compact, cyanide mill was installed.

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  • Gold and Silver Leaching by Cyanidation

     · The cyanide leaching process is the most important method ever developed for extracting gold from its ores. The early development of the process is attributed to a Scotchman, John Stewart Mac Arthur, in collaboration with the Forrest brothers. The method was introduced into South Africa in 1890. From there it spread to Australia, Mexico and the ...

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  • Estimated Water Requirements for Gold Heap-Leach Operations

    (L) of water or strong cyanide solution per metric ton of ore may be added to the mix of ore and cement if the moisture content of the ore is below 8 percent (McClelland, Pool, and Eisele, 1983; Hoye, 1987; Randol International Ltd., 1992, p. A-699, 5,750, 5,796; Bouffard, 2005).

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  • CYANIDE AND CYANIDE COMPLEXES IN THE GOLD

    the ore; the ore and solvent are put in large tanks for hours to dissolve the gold. Heap Leaching is employed by the mining company for the low-grade ores, solution of sodium (potassium) cyanide are sprayed to dissolve the gold. Once the ore has been mined, it is finely ground in a large-revolving cylinder containing large steel balls.

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  • Extraction of gold using cyanide

    too large to react readily with the cyanide. If the gold ore contains other metals and/or sulphide minerals it may require additional treatments prior to the leaching process. The treated gold then has sodium cyanide added to it and the following reaction known as Elsener''s equation occurs: 4Au + 8CN-+ O 2

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  • Gold-copper ores

     · As molar ratio of 4:1 cyanide to copper is required to maintain acceptable gold cyanidation rates, this is typically taken into consideration during the ore-testing phase. However, significantly higher cyanide consumption can occur in practice than is expected on the prima facie cyanide-soluble copper content, due to the recycling of copper ...

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  • Processing of High-Silver Gold Ores

     · (45.1), and for the corresponding equilibria for other cyanide complexes (Wang and Forssberg, 1990). Silver forms intermediate or weaker cyanide complexes, which encourages the use of higher cyanide strength solutions if significant revenue is to be derived from silver recovery. Download : Download full-size image; Figure 45.1.

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  • University of Alberta

    been studied by using three oil sands ores tested with a laboratory hydrotransport extraction system (LHES) and a Denver flotation cell. ... ratio (B/S) ... ratio of bitumen froth, using 1 kg Syn704 ore, 45 °C, 3m/s, no conditioning prior to

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  • Mine Tailings

     · Hazardous Properties. Toxic chemicals used to extract the valuable materials from the ore, such as the cyanide used in gold mining, remain in the tailings at the end of the process, and may leach out into ground water. Rock may naturally contain dangerous chemicals, such as arsenic and mercury, which leach into water much more readily after rock has been ground up and exposed to the …

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  • Cyanide

    In the cyanide process, finely ground high-grade ore is mixed with the cyanide (at a ratio of about 1:500 parts NaCN to ore); low-grade ores are stacked into heaps and sprayed with a cyanide solution (at a ratio of about 1:1000 parts NaCN to ore).

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  • CYANIDE RECOVERY COST EFFECTIVENESS IS WHY RECYCLE …

    cyanide destruction and cyanide recovery costs for a fairly generic high cyanide-consuming case. The capital cost of a cyanide recovery plant could pay back in less than 2 years in many cases, particularly when high cyanide consumption is associated with copper mineralisation in the ore. As a broad generalisation, cyanide recovery

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  • Leaching and recovery of gold from ore in cyanide-free ...

     · 1. Introduction. Currently, cyanide is the predominant lixiviant used to extract gold due to its strong complexation with gold and the technical simplicity of the leaching process (Avraamides, 1982, Habashi, 1987, Marsden and House, 2006).However, the use of cyanide can bring challenges in terms of environmental, health and safety aspects (Aylmore, 2005, Laitos, 2012).

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  • gold cyanide leaching process

     · And the specific dosage of cyanide agent should be determined according to the property of gold ore. 4. Pulp density. The slurry solid-liquid ratio is the pulp density, which can directly affect the diffusion rate of components, and then affect the gold leaching rate and speed.

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  • Cyanide Leaching Of Gold

    The cyanide solution strength is also important in leaching gold, with the typical range of solution being in the 0.02% -0.05% NaCN. The gold particle size has a tremendous effect on the time required for dissolution in a cyanide solution. Generally, the finer the gold, the quicker it will dissolve. A 45 micron particle of gold would dissolve ...

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  • Agitated Cyanide Gold Leaching Test

     · A certain amount of cyanide solution is poured on each day and allowed to percolate slowly through, the daily proportion being regulated by the number of days treatment and ratio of solution decided on. Such ratio may be from ¾ to 1½ times the weight of ore taken for percolation.

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  • 1.1 PHASES OF A MINING PROJECT

    The ratio of the quantity of overburden to the quantity of mineral ore (called the ''strip ratio'') is usually greater than one, and can be much higher. For example, if a proposed mining project involves the extraction of 100 million metric tons of mineral ore, then the proposed mining project could generate more than one billion metric tons

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  • Gold Cyanidation: Process & Environmental Impacts | Study

    The process, called gold cyanidation, makes gold water-soluble, and thus easier to isolate from the ore. While using cyanide allows for the profitable extraction of gold from low quality ores, it ...

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  • Assaying Ores to determine gold content

    This is a preliminary test to determine the leach ability of an ore by cyanide. In this type of test, a known quantity of pulverized sample is placed in a bottle with dilute cyanide solution. The bottle is placed on an apparatus that rotates the bottle keeping the sample and cyanide solution mixing together at all times.

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  • Tailings Dam

     · B. Sceresini, P. Breuer, in Gold Ore Processing (Second Edition), 2016. 2.6 Effect of Copper–Cyanide Complexes on the Gold Cyanidation Process. As molar ratio of 4:1 cyanide:copper is required to maintain acceptable gold cyanidation rates, this is typically taken into consideration during the ore-testing phase.

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  • Lecture 4: Mining waste

    The ratio between waste rock and ore production is called the stripping ratio. For example, a stripping ratio of 2:1 means that 2 tonnes of waste rock needs to be mined to mine 1 tonne of ore. Generally, an open pit mine has a higher stripping ratio than an underground mine. Waste rock is often stored close to the mine to minimize transports.

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  • An example of cyanide trough leaching for gold ore_Henan ...

    The coarse and fine ore sand is dug out by excavator to dry and grind into fine powder, and then it is mixed according to the ratio of coarse sand: fine sand= 3: 1. The mixed ore is the original ore of leaching by percolation cyanide trough, with gold content of 3.48 g / t, water content of 5% to 6%, withgrain size 40% -0.074 mm.

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  • Stripping Ratios: What are They and Why are They Important ...

     · Ore quality is another consideration in stripping ratios. That''s because if a deposit contains low-quality ore, more of it must be mined in order …

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  • ratios of cyanide and ore when leaching

    The cyanide dissolves the gold from the ore into the solution as it trickles through the heap. (PDF) Leaching and recovery of gold from ore in cyanide-free ... The investigated parameter range was 0.52 M for glycine concentration, pH of 1012 and temperatures of 2360 °C, with constant leaching time (24 h) and solid/liquid ratio (100 g/L).

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  • Ore

    Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit. Ore is extracted from the earth through mining and treated or refined, often via smelting, to extract the valuable metals or minerals. The grade of ore refers to the concentration of the desired material it contains.

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  • Use in Mining | International Cyanide Management Code ...

    The cyanide then dissolves gold and silver from the ore and forms a stable metal-cyanide complex. The use of oxygen or peroxygen compounds instead of air as an oxidant increases the leach rate and decreases cyanide consumption, due to the inactivation of some of the cyanide consuming species present in the slurry.

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  • Gold Ore With A 4.4 G/ton Au Grade Is Leached With ...

    Question: Gold Ore With A 4.4 G/ton Au Grade Is Leached With Cyanide At A 35% Solid Ratio According To The Reaction Below: 2 Au° + 4NaCN + 02+ 2H20 = 2[Au(CN),?] + 4NaOH A) Calculate The NaCN Concentration (g/L) Necessary To Leach Gold Completely? Calculate The Minimum Amount Of NaCN Necessary To Leach 1 Ton Ore (g NaCN / Ton Ore)? (Density Of Leach Solution ...

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  • Geometallurgical Approach for Implications of Ore Blending ...

     · Many gold mining companies globally have reported a continuous decline in gold ore grade (Domínguez and Valero 2013; Neingo and Tholana 2016) mand for most commodities, including gold, continues to grow and is unlikely to be met by discovery and recycling of metals alone (Kesler 2007; Valenta et al. 2018) principle, the supply gap may be filled by discoveries of new deposits, …

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  • Calcium Sulfide Precipitation of Mercury During Cyanide ...

    during gold ore leaching and to remove mercury from cyanide leach solu­ tions. Mercury dissolution was reduced from 40 to 10 pct by decreasing NaCN concentration from 20 lb to 0.34 lb per ton of solution at a pH of <11. When 0.1 lb CaS per ton of ore was added to a leach slurry, mer­

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  • Cyanide Gold Extraction Process

     · Cyanide gold extraction process, the process of extracting gold with cyanide is called cyanidation gold extraction, which is the main method for extracting gold from ore or concentrate.. Basic Gold Cyanide Process Steps. The cyanidation gold extraction process includes cyanide leaching, washing and leaching of the leaching slurry, extraction of gold from the cyanide or cyanide slurry, and ...

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

    above 290 mV Eh, cyanide was consumed and no free cyanide was detected in solution. On the basis of this test, H202 was added to cyanide leaching slurries to maintain the potential between 110 and 220 mV Eh. Ideally, such a test series would be run for each ore …

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  • The story of how ''Cyanide Charlie'' got his nickname ...

     · The Homestake manager at the time, Thomas J. Grier, was willing to take a chance on Merrill''s theories, agreeing to build an experimental plant for processing crushed gold-ore sand …

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  • ANALYSIS OF CYANIDE

    HCN and CN-in solution are classified as free cyanide. -The ratio of HCN to CN in solution is influenced by the solution pH. Methods used to separate and detect free cyanide should not alter the stability of weaker cyanide complexes, or they may be included in the free cyanide …

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  • Solved: Gold Ore With A 4.4 G/ton Au Grade Is Leached With ...

    Question: Gold Ore With A 4.4 G/ton Au Grade Is Leached With Cyanide At A 35% Solid Ratio According To The Reaction Below: 2Au° + 4NaCN + O2+ 2H,0 = 2[Au(CN)2) + 4NaOH A) Calculate The NaCN Concentration (g/L) Necessary To Leach Gold Completely? Calculate The Minimum Amount Of NaCN Necessary To Leach 1 Ton Ore (g NaCN / Ton Ore)? (Density Of Leach Solution Is ...

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  • CN103290232A

    The invention relates to a method for extracting gold through potassium ferricyanide. The method is characterized in that the gold is extracted from the auriferous ores under an alkaline environment at normal temperature and pressure with nontoxic ferricyanide serving as a gold leaching agent and calcium peroxide serving as a leaching adding agent; and the method is a completely novel cyanide ...

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  • 58.01.13

    cyanide solution, which is the primary leaching agent for extraction. (4-11-06) 04. Cyanidation Facility. That portion of a new ore processing facility, or a material modification or a material expansion of that portion of an existing ore processing facility, that utilizes cyanidation and is intended to

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  • TV:BIP Ratio Explained: The Economics of Oil Sands Mining ...

     · Defined as the weight of overburden (or waste ore) divided by the weight of oil sands ore, a strip ratio of 2 is considered high but feasible if the ore grade is high enough. A better measure of mining economics is the TV:BIP ratio. TV:BIP is a ratio of the total volume of oil sands mined (TV) to the total amount of bitumen in-place (BIP).

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