Several reagents are known to leach native gold from gold-bearing ores. It has been known for more than a century that alkaline solutions of alkali-metal cyanides e.g., NaCN, KCN dissolve gold under aerated conditions. The dis-solution of metallic gold is due to the strong complexing capabilities of cya-nide anions combined with the oxidizing
Jun 01, 2007 Goldchloride complex is rather unstable and may re-precipitate upon contact with a reductant, such as sulfidic materials of ore. Puvvada and Murthy 2000 used chloridehypochlorite solution to leach gold and silver from a chalcopyrite concentrate. Direct hypochlorite leaching of the sulfidic concentrate yielded gold and silver recoveries of 43 and 45, respectively.
In Liddells Handbook of Nonferrous Metallurgy, Vol. 2, 1945, there is to be found a very complete account of the uses of chlorine as applied to the recovery of gold and silver, in Chlorination Processes amp Methods. Introducing the chapter entitled Chlorine Metallurgical Processes Liddell says Chlorine as a metallurgical agent appears to have lost ground during recent years, and much ...
Oct 10, 2019 Gold chloride leaching is generally faster than cyanide, the fast leaching kinetics reportedly favored by low pH, high chloridechlorine concentration, increased temperature, and the high reactive surface area of the reactive ore particles.
This reveals that the leaching behavior of gold in the chlorination process is the key to improve the gold leaching rate. Hence, the leaching behaviors of gold at different concentrations of NaClO3, NaCl, and H2SO4 were evaluated in this study.
Recently, 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.
Therefore, during cyanide leaching process, it is difficult for the cyanide solution to contact with gold mineral, so the gold leaching rate is often low. Solution After reaching a certain degree of monomer dissociation, for gold ores with low arsenic content, aqueous solution oxidation, aqueous chlorination, bacterial oxidation, etc. can be used.
The invention claimed is 1. A cyanide-free process for recovery of gold from an ore comprising the steps of i providing the ore comprising the gold to be recovered ii leaching the ore in a chloride oxidative medium, comprising nitric acid to produce a chloride solution comprising gold and iii recovering the gold from the chloride solution, wherein recovering the gold from the chloride ...
A process for treating a particulated gold bearing ore to recover the gold therein is disclosed. The process includes roasting the ore to remove sulfides as sulfur dioxide followed by chlorination of the ore at a temperature of about 350 C. in the presence of iron to form a mixture of volatile gold chlorides and volatile gold-iron chlorides in the chlorine off gases followed by condensing ...
In a method for leaching gold from copper sulfides, the sulfide ores are first subjected to leaching of copper, thereby producing a leaching residue having 7.9 or less of the copper content. This leaching residue is mixed with a leach liquor, which contains the chloride ion and ferric ion and has 1.9 or less of pH. Gold and copper can be effectively leached from the copper sulfide ores.
Leaching of an oxide gold ore with chloridehypochlorite This rate is much higher than the gold dissolution rate of 2.5 mgcm 2 h obtained in 2 gL of cyanide solution Tran et al., 2001.The performance of chloridehypochlorite solution for gold leaching also
The Chlorination of Gold Ores. By Mr. Donald Clark, M.M.E., B.C.E. The ideal method for extracting fine gold would be to dis-solve out the gold with some solvent which would not attack other minerals present. The solvents known 6o years ago were chlorine, bromine, and cyanide of potassium. Yet in
But the highest leaching rate of gold was identified as approximately 92.8, and it was difficult to achieve higher rates by controlling the conditions of temperature, time, and concentrations of H 2 SO 4, NaCl, and NaClO 3. This reveals that the leaching behavior of gold in the chlorination process is the key to improve the gold leaching rate.
A synergistic extraction method for gold from the refractory gold ores via ultrasound and chlorination-oxidation was developed. The effects of solid-liquid ratio, extraction time, ultrasound power, NaClO concentration and NaOH concentration on the extraction rate of gold from the refractory gold
Gold of either 99.99 or 99.999 purity can be produced from intermediate process products having a wide range of gold contents. The process comprises oxidative leaching of the solid feed, followed by selective solvent extraction of the gold from the leach liquor to reject impurities, and precipitation of high-purity gold powder.
ore. A ferric chloride FeCI3 preleach, at 40 C in 6 h, extracted about 50 pct of the zinc and formed insoluble silver and lead chlorides. Subsequent acid thiourea leaching, for 1 to 3 h at 40 C, extracted about 85 pct of the gold and silver. Lead chloride was solubilized from
The target of this review is to point out the best cyanide-free processes of following methods and reagents Bioleaching, Chlorination, Aqua Regia, Bromine, Thiocyanate, Thiosulfate and Thiourea leaching. For this propose, the gold leaching reagents are described and discussed in terms of their environmental and economical points of view.
Put a drop of gold detection liquid on the wet spot on the paper towel. If any gold is still dissolved in the acid, the wet spot will turn a purple-black or a purple-brown. If you see this color change then give the precipitant more time to work andor add more precipitant, and repeat the test until you determine that no gold is dissolved in ...
Thus, the bulk of the gold may be recovered by leaching techniques using cyanidation or aqueous chlorination, and the residue may then be treated by smelting to recover the balance. Generally, scrap with a gold content of less than 0.1 percent, unless readily recoverable by leaching, is recycled back to a pyrometallurgical process.
This article describes KUCs slimes process improvements, in particular wet chlorination for gold leaching. Kennecott Copper Anode Slimes Process The KUC refinery is located at Magna, approximately 16 miles west of Salt Lake City, Utah, USA. In the refinerys tank house, commercial anodes from the KUC smelter are electrorefined.
Mehdi Ghobeiti Hasab, Fereshteh Rashchi, Shahram Raygan. Simultaneous sulfide oxidation and gold leaching of a refractory gold concentrate by chloridehypochlorite solution, Minerals Engineering, 2013. 5051 140142 CrossRef Google Scholar
The high pressure briquetting machine or the high pressure ball press machine is used to press many kinds of materials such as gypsum, coal powder, mineral powder, scale cinder, slag, fine iron powder and aluminum ash etc.
Compound cone crusher is also called compound spring cone crusher. Compound cone crusher, is a cone crusher with integrated springs and hydraulic cylinder type cone crusher, above the average of broken items can be broken with it.