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The gold industry has been seeking alternative reagents for leaching gold from lowgrade ores for the past 25 years. The cost and transport of cyanide, the poor recovery of gold from carbonaceous ores, the lack of selectivity of cyanide towards copper minerals and the cost of waste treatment are real factors which can make cyanide unattractive in some circumstances.

Cyanide is destroyed by sodium thiosulfate or sodium nitrite. An average fatal dose of HCN is about 5060 milligrams. Cyanide dissolves both gold and silver from alkaline solution. Cyanide is a very "clean" extraction system, as it does not extract many of the base metals such as iron.

There has been extensive research on thiosulfate leaching for gold extraction since the –31,34–41) Ammonium thiosulfate leaching process is also applicable for the heap leaching,31) However, there are problems in commercializing the thiosulfate process in the gold milling industry, the problems are the most notably high ...

Jul 27, 2012· Sodium thiosulfate will leach gold (dissolve gold), in the use of sodium thiosulfate to leach ore they use air or oxygen, many times ammonia is added, many time''s copper is used as a catalyst for the reaction, keeping the pH regulated is also important for the leach to work.

In thiosulfate gold leaching, Cu2+ ions are commonly used as oxidizing agents, while the thiosulfate ion acts as a ligand forming a soluble gold thiosulfateammonia complex (Aylmore and Muir, 2001). It was suggested that gold leaching in the absence of Cu2+ ions, with an external current acting as a oxidizer, is not possible

lurgical gold extraction routes utilize a leaching step to produce a goldbearing solution as an intermediate product while the recycling of secondary gold from electronic and precious metal scrap is based on the selective and fast dissolution of the precious metal. Therefore, A Method for Leaching or Dissolving Gold from Ores or Precious

Gold leaching was primarily limited by the volume of lixiviant contacting the carbonaceous matter; however, a slight kinetic limitation was observed in ammoniacal thiosulfate leaching at higher flow rates. The percentage of gold leached by sodium cyanide from carbonaceous matter demineralized from autoclaved Goldstrike ore was

Nov 14, 2016· Growing Largest Sodium Thiosulfate Crystals Possible.

Abstract: Arsenopyrite was artificially added into the thiosulfate leaching solution to clarify the role of arsenopyrite on the thiosulfate leaching of gold. The effect of arsenopyrite on the thiosulfate leaching of gold was studied by the thermodynamic calculation, mineral dissolution test, leaching test .

Leaching of PCB''s with sodium thiosulfate and ammonium thiosulfate. In this step, sodium and ammonium thiosulfate were used to extract gold and silver of whole PCBs. In both leachates, the effect of adding copper, as a catalyst agent, and hydrogen peroxide, as the oxidizing agent to .

May 27, 2017· Crush your ore to the consistency of fine sand in a rod mill, then transfer it into a large vat with a strong solution of sodium thiosulfate and agitate it with paddles for a day to a week, depending on the size of your vat. Finally, filter and di...

Thiosulfate leaching can be considered a nontoxic process, the gold dissolution rates can be faster than conventional cyanidation and, due to the decreased interference of foreign cations, high gold recoveries can be obtained from the thiosulfate leaching of complex and carbonaceoustype ores.

Sodium thiosulfate (sodium thiosulphate) is an inorganic compound with the formula Na 2 S 2 O 3. x H 2 O. Typically it is available as the white or colorless pentahydrate, Na 2 S 2 O 3 ·5H 2 solid is an efflorescent (loses water readily) crystalline substance that dissolves well in water. It is also often called sodium hyposulfite or hypo.. Sodium thiosulfate is used in gold mining ...

The proposed method of the gold recovery comprises leaching with a solution of a mixture of sodium and ammonium hydrosulfite and thiosulfate, by sorption of the thiosulfategold complex on a highly basic anion exchanger and by isolation of the highly basic anion exchanger, the sorption being carried out 210 hours after the leaching. Then the ...

Associated Sulfide Minerals in Thiosulfate Leaching of Gold: Problems and Solutions by ... Abstract The effects of some associated minerals on thiosulfate gold leaching were studied through thermodynamic analysis and leaching experiments on composite ... thiosulfate leaching strategies, satisfactory gold extractions and thiosulfate ...

Thiosulfate leaching offers a number of benefits related to gold recovery yields and environmental concerns: Thiosulfate leaching of gold ores has great potential to reduce the impact on the environment. Unlike cyanide, which is highly toxic, the chemicals used in the thiosulfate leaching process are benign.

Nov 09, 2015· i am using sodium cyanide for gold leaching,i know that it is very dangerous and harmful to envoirnment,so i want to know about other chemical which can leach gold and silver i want to know how about thioleaching. Top. ... I have never used the thiosulfate leach, that is why I said I suspect, it was just based on an assumption, of how ...

Sep 04, 2011· I have a few pieces of computer parts that I would like to extract the gold from. I heard that you can leach it out with sodium thiosulfate which makes a strong complex of gold ions to make [Au(S2O3)2]3−. Is there a way you can get it out of this form? I know there is a way because it is used in gold leaching as an alternative to cyanide in mining operations.

Feb 24, 2014· recovered powders from a sodium thiosulfate leach of gold plated pins. if all my experiments can be perfected, i will have a safe, nontoxic process to remove gold from gold .

THIOSULPHATE LEACHING – AN ALTERNATIVE TO CYANIDATION IN GOLD PROCESSING ALTERNATIVES TO CYANIDE IN GOLD PROCESSING THIOSULPHATE LEACHING Thiosulphate leaching is a process that removes gold from gold bearing ores without the use of cyanide. Although not as aggressive a leaching agent as cyanide, thiosulphate offers several technological

Thiosulfate extensively forms complexes with transition metals hence a common use is dissolving silver halides in film photography developing. Thiosulfate is also used to extract or leach gold (sodium thiosulfate) and silver from their ores as a less toxic alternative to cyanide. Nomenclature

Sodium thiosulfate is a component used as an alternative leaching agent to cyanide for the extraction of gold. However, it forms a strong soluble complex with the ions gold (I), [Au (S 2 OR 3 ) 2 ] 3 .

Sodium thiosulfate is used in gold mining, water treatment, analytic chemistry, the development of silverbased photographic film and prints, and medicine. The medical uses of sodium thiosulfate include treatment of cyanide poisoning and pityriasis. It is on the World Health Organization''s List .

Thiosulfate leaching can be considered a nontoxic process, the gold dissolution rates can be faster than conventional cyanidation and, due to the decreased interference of foreign cations, high gold recoveries can be obtained from the thiosulfate leaching of complex and carbonaceoustype ores. In addition, thiosulfate can be cheaper than cyanide.
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