08-11-2017· Leaching pure gold with an acidic sodium hypochlorite solution has been demonstrated to be effective. The initial rate of gold dissolution was extremely rapid. In a leaching solution containing 1 g/L NaCl, 1 % HCl and 2 % NaOCl, nearly 90 % of the gold was extracted in only 30 minutes.
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01-06-2007· Calcium hypochlorite produced a sluggish gold leaching kinetics, requiring twice more time (46 h) to achieve the maximum gold recovery of 58% compared to sodium hypochlorite. To have a reasonable gold leaching kinetics, it was found that OCl −
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discuss the leaching characteristics of gold in hypochlorite leaching solutions. The dissolution of gold in a hypochlorite solution not only depends on the concentration of the hypochlorite but also on other variables, such as hydrochloric acid, sodium chloride and temperature. The dissolution rate of gold in hypochlorite solution is much faster
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Due to formation of CaOCl + complex in solution and hence less reactivity, calcium hypochlorite produces a sluggish gold leaching kinetics, taking twice the time (46 h) to achieve maximum gold recovery of 58% compared to sodium hypochlorite. 10 g/L of total initial hypochlorite species in solution produces reasonable gold recoveries.
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Direct hypochlorite leaching of the sulfidic concentrate yielded gold and silver recoveries of 43% and 45%, respectively.After pressure oxidation of the concentrate and subsequent hypochlorite leaching, the recoveries increased to 90% for gold and 93% for silver.
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2000). Leaching of gold with hypochlorous acid follows reaction (1) (Jeffrey et al., 2001): +2Au + 3HOCl + 3H + 5Cl¯ 2[AuCl 4]¯ + 3H 2 O. (1) Controlling solution pH and Eh is important for stabilizing the gold complex. Fail-ing to do this would cause the gold to reprecipitate, after it is dissolved from the ores
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24-04-2017· Bleach is the chemical compound sodium hypochlorite. When combined with hydrochloric acid, the mixture produces chlorine that dissolves gold from gold ore. This was the first commercial method used for gold extraction. Place the ore into the mortar and grind it to the size of sand grains.
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The method of chloride-hypochlorite leaching has the advantages of short process, low pollution and higher in reaction rate compared with the traditional leaching method. In this research, NaCl — NaClO solution is used to leaching gold from a refractory gold concentrate, and the influence of NaCl and NaClO concentration, reaction time to the leaching rate were investigated in this experiment.
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30-04-2018· Gold Extraction Method Replaces Cyanide With Non-Hazardous Hypochlorite. Quebec mining company achieves third-party certification using extraction method. Cyanide has been used in the process of mining gold since 1887. When a dam burst at a gold mine in northwestern Romania in 2000, contaminated wastewater poured into tributaries of a major
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26-09-2015· Plus, you will lay out more money in acid to try and remove base metals from ore than you will likely ever hope to recover from that ore in gold. Most patents show leaching with sodium hypochlorite to be done at a pH closer to neutral (7), at which point the sodium hypochlorite is converted to the powerful oxidizer hypochlorous acid.
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Leaching of an oxide gold ore with chloride/hypochlorite solutions. S. Chero-Osorio. Related Papers. A Comparative Study of Cyanide and Chloride Hypochlorite Gold Leaching of Oxide Ore from Placer, Surigao Del Norte. By Renee Alexis Taladua. Application of Alternative Lixiviants for Secondary Heap Leaching of Gold.
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The performance of chloride/hypochlorite solution for gold leaching also depends on major minerals pres-ent in the ore. Gold–chloride complex is rather unstable and may re-precipitate upon contact with a reductant, such as sulfidic materials of ore. Puvvada and Murthy (2000) used chloride/hypochlorite solution to leach gold
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Abstract An oxide gold ore was subjected to chloride/hypochlorite leaching at room temperature. The effects of three factors, including Ca(OCl)2 vs. NaOCl, OCl− concentration, and HCl concentration on gold leaching performance were investigated. Due to formation of CaOCl+ complex in solution and hence less reactivity, calcium hypochlorite produces a sluggish gold leaching kinetics, taking
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The method of chloride-hypochlorite leaching has the advantages of short process, low pollution and higher in reaction rate compared with the traditional leaching method. In this research, NaCl — NaClO solution is used to leaching gold from a refractory gold concentrate, and the influence of NaCl and NaClO concentration, reaction time to the leaching rate were investigated in this experiment.
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An oxide gold ore from Placer, Surigao Del Norte was subjected to chloride-hypochlorite and cyanide leaching at room temperature at 3 different hours 4 hours, 12 hours and 24 hours. This project characterized the ore used and assessed the effects
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20-01-2021· Chloride-hypochlorite technology for leaching gold from ores and concentrates. We have developed a chloride-hypochlorite technology for leaching gold in an alkaline medium with a pH of 8-8.5. This technology allows the system to operate under less corrosive conditions with lower chloride concentration and can be used as an alternative to cyanide.
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Two-stage leaching was carried out: first to eliminate manganese from the sample using sodium sulfite (Na 2 SO 3) as a reductive reagent and sulfuric acid (H 2 SO 4) and a second stage to dissolve silver and gold with sodium hypochlorite (NaClO) and hydrochloric acid (HCl); the results show extraction around 96% for Mn and 98.73% and 83% of Ag and Au, respectively.
Get Quote26-02-2018· A good starting recipe for neutral pH leaching is water with 20% salt (supermarket, non-iodised) with 1% calcium hypochlorite, add HCl to pH 7. If you do not have anything present in the leach which will consume high levels of hypochlorite, such as sulfides, then any gold in solution will stay in solution almost indefinitely.
Get Quote22-06-2020· If the gold ore is still difficult to be successfully leached after being finely ground, the gold ore is called refractory gold. Generally, the grade of Au in the tailings is greater than 0.5g/t. The gold in this type of ore, either physically wrapped or chemically combined, cannot be in contact with the cyanide solution, so it is difficult to be leached.
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Keywords: gold leaching, ammonium thiosulfate, chloride, thiourea, thiocyanate Introduction The most common hydrometallurgical methods of primary raw material utilization in the production of gold are based on the use of cyanide (Hilson, 2006). In this method a weak sodium cyanide solution (NaCN) of 100-500 ppm is used. Since the Baia Mare
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