These systems involve leaching the solids in a slurry using different sources of chloride—such as chlorine gas, hydrochloric acid, or ferrous chloride—and subsequently reacting the resulting slurry with oxygen at less than 50 psig pressure and a temperature of about 110° C. Metals such as Cu, Ni, Zn, Co, and Cd were converted to soluble ...
اقرأ أكثرMore than a century ago, gold ores were treated by roasting and subsequent leaching with aqueous solution of chlorine. Ross (1902) reported that chlorine consumption was 3 - 10 kilograms per tonne of ore and the gold extraction was 90 - 98 per cent MacArthur and Forrest introduced the cyanidation process in 1887. Cyanide
اقرأ أكثرAbstract This paper deals with gold extraction from a refractory concentrate by chlorine leaching. The process considers a pre-treatment of refractory materials by low temperature oxidation carried out with low oxygen concentration. The oxidized material is treated by leaching with brine. After gold adsorption/reduction onto activated carbon, iron and base metals can be precipitated by NaOH.
اقرأ أكثرSpecial Directions for working A. Concentrated pyrites containing gold Roasting Charging the vat Chlorination Making chlorine Leaching the gold Precipitating the gold Iron sulphate solution Collecting the gold Washing the gold Drying the gold Melting the gold B. Concentrated pyrites containing gold and silver Roasting Leaching the silver Precipitation of silver Collecting the precipitate ...
اقرأ أكثرDirect leaching of ores becomes very expensive using chlorine systems. I have tested leaching of gold in worked out mining areas using thiourea in an acid environment - results, leaching and absorption onto carbon was remarkable. The problem however was the environmental issues associated with thiourea. There is a lot of literature on this.
اقرأ أكثرLeach Gold Ore with Chlorination. Thread starter meatheadmerlin; Start date Sep 25, 2015; M. meatheadmerlin Well-known member. Joined Mar 6, 2013 Messages 105
اقرأ أكثرDec 10, 2010. #4. The ratio is irrelevant. Start with enough Hcl to absorb the volume of gold,then add NaOCl in small amounts and give it time to work in between additions.The Hcl is only there to digest the gold (creating the auric chloride)when it has been oxidized using the NaOCl. If you can not find SMB you can use copperas (FeSO4, iron (ii ...
اقرأ أكثرGold can be leached from stone through alkaline or acidic-based products, including halogens, such as chlorine, iodine and bromine. Halogens are reactive, non …
اقرأ أكثرChloride–hypochlorite oxidation and leaching of refractory sulfide gold concentrate 63 Fig. 1. The Pourbaix diagram of Fe–S at [Fe] –= 10 4 M, [S] = 10– M and 25 C (the chlorine species regions are also marked) (Marsden and House, 2005) Fig. 2.
اقرأ أكثرThe chlorination method is one of the ways to leach gold into a soluble gold chlorine complex from an aqueous chloride solution such as sodium chloride. In general, the chlorinating agent is chlorine gas or hypochlorite. The leaching reaction is as follows: (5) 2 Au + 3 Cl 2 + 2 Cl − = 2 Au Cl 4 − (6) 2 Au + 3 Cl O − + 6 H + + 5 Cl − ...
اقرأ أكثرA method for selectively recovering metals from generally sulphidic particulate materials containing metals selected from nickel, copper and precious metals in which the particulate material is preferentially leached in an agitated chloride solution containing cuprous ions by the action of chlorine. The redox potential of the solution increases upon feeding chlorine thereto and decreases upon ...
اقرأ أكثرIn order to find the optimum conditions of gold leaching with the highest rate of extraction (gold recovery), numerical optimization was carried out using DX software, which is demonstrated in figure 7. It was found that the maximum gold recovery could be obtained of approximately 91.5%, with a desirable value of , by numerical optimization.
اقرأ أكثرYour Gold is in the precipitate, it's common to get precipitation in two parts like this with dirty solutions or first drops from leaching ore. The lighter Precipitate is usually from drag down of other metals with the Gold or can be from excess precipitant.
اقرأ أكثرChlorine leaching, as a potential alternative to the conventional cyanidation for the extraction of gold, was tested on a sulphide concentrate and its calcine from the Pearl River Area, South China. The basic feasibility of using the resin-in-leach (RIL) technique in chlorine leaching of the gold-bearing sulphide concentrate and its calcine is ...
اقرأ أكثرAll the industrially applied gold leaching methods (historical chlorine gas based leaching, dominating state-of-the-art cyanide gold leaching, processes at precious metals plants) suffer from the ...
اقرأ أكثرRecently, the U.S. Bureau of Mines examined the recovery of gold by chlorination of refractory carbonaceous and sulfidic ores, comparing various treatment methods in which a ground ore pulp is contacted with chlorine gas and activated carbon is added to the pulp for a carbon-in-chlorine leach (CICL). The objective of this research was to demonstrate the basic feasibility of CICL technology ...
اقرأ أكثرThe Newbery–Vautin chlorination process is a process to extract gold from its ore using chlorination developed by James Cosmo Newbery and Claude Vautin.. Background. The process of gold extraction from ores via its absorption in chlorine gas, from which it …
اقرأ أكثرIn a leach solution containing 20 % HCl and 20 g/L NaCl, 97 % of the gold was extracted in 6 hours with 90 kg/t available chlorine and 95 % of the gold was extracted in 18 hours with 45 kg/t available chlorine. For a refractory ore, pretreatment is required in order to expose the gold surface to the leach solution.
اقرأ أكثرCLS will leach pieces of gold 40 mesh and smaller within 8 to 12 hours. This is a definite advantage over cyanide which can take up to a week to leach 40 mesh gold. This presents a number of trade-offs between CLS and cyanide. In most cases, the CLS leaching system can …
اقرأ أكثرChlorine leaching, as a potential alternative to the conventional cyanidation for the extraction of gold, was tested on a sulphide concentrate and its calcine from the Pearl River Area, South China. The basic feasibility of using the resin-in-leach (RIL) technique in chlorine leaching of the gold-bearing sulphide concentrate and its calcine is ...
اقرأ أكثرAll the industrially applied gold leaching methods (historical chlorine gas based leaching, dominating state-of-the-art cyanide gold leaching, processes at precious metals plants) suffer from the ...
اقرأ أكثرChlorine/hydrochloric acid mixtures are still used today to dissolve gold and platinum group metals (PGM's) in various precious metals refineries around the world. Chloride processes for gold extraction . have continued to attract some attention [2,3], although …
اقرأ أكثرBromine can dissolve (leach) >90% of gold smaller than about 75, but is too slow for leaching larger gold. (compiler: Robin Grayson) (compiler: Robin Grayson) World Placer Journal – 2007 ...
اقرأ أكثرThe percent of gold extractions in the tests of this example for the chlorine leach and cyanide leach steps is higher than those of the preceding examples, but the additional recovery of gold using cyanide leaching remains about the same.
اقرأ أكثرThe method consist in leaching the gold with chlorine resulted from NaClO decomposition in hydrochloric acid medium, (AuCl4) - selective recovery from hydrochloric solutions by adsorption on …
اقرأ أكثرLeaching of an oxide gold ore with chloride/hypochlorite solutions ... Chlorine had been used to dissolve gold from ores and concentrates, during the second half of the 19th century in Australia and North America. At the begin-ning of the 20th century, this process was gradually
اقرأ أكثرThe total gold leaching ratio of a refractory As-, S- and C-bearing gold concentrate calcine by direct cyanidation was only 70.2%, but there was a significant variation in the gold leaching ratio based on size fraction, in the following order: medium size fraction (82.6%) > …
اقرأ أكثرAfter dissolution of all the metals except gold, the continued addition of chlorine to the leach slurry causes an abrupt rise in potential until gold starts to dissolve, after which sufficient additional chlorine is fed to the slurry to dissolve most of the gold. ... Thus the chlorine leaching part can be applied, for example, to separation of ...
اقرأ أكثرSodium cyanide has been the preponderant leaching reagent for gold due to its excellent extractions from a great variety of ores and its low cost. Although cyanide is poisonous, it has safe industrial and environmental records at the high pH range required in cyanide leaching. In addition, the low concentrations of cyanide used in gold milling ...
اقرأ أكثرAn 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, …
اقرأ أكثر