Pdf thiosulfate leaching of gold from waste mobile phones. Pdf file or convert a pdf file to docx, jpg, or other file format. Barrick gold s goldstrike mine will be the largest scale use of the alternative lixiviant the world has ever seen. A pdf portable document format is a widely popular type of document format created by adobe. Biooxidationthiosulfate leaching of refractory gold concentrate. Unlike cyanide, which is highly toxic, the chemicals used in the thiosulfate leaching process are benign. If your scanner saves files as pdf portbale document format files, the potential exists to merge the individual files into one doc. Therefore, a method for leaching or dissolving gold from ores or precious. Thiosulfate leaching is also sensitive to mineralogy because reactive sulfides consume oxygen and copperii while clays may adsorb pregrob copper and gold from leach liquors 21. Us6632264b2 gold recovery from thiosulfate leaching.
Leaching studies were conducted with copper minerals, copper minerals with gold addition to solution and copper gold samples of different copper and gold grades. The main chemical components of the thiosulfate leaching process ammonium thiosulfate and ammonium sulphate are common fertilizers. How gold is extracted by cyanidation process refresh science. Adsorption studies were carried out with the actual ammoniacal thiosulphate solution coming from the leaching of the gold ore sample. Description online access for this thesis was created in part with support from the institute of museum and library services imls administered by the nevada state library, archives. Pdf thiosulfate leaching of gold from waste mobile. The copper sulfide minerals chalcopyrite and enargite seem to be unreactive toward an ammonium thiosulfate leach. Effect of additives on thiosulfate leaching of a gold ore. This work is done in the technological institute of parral in a lowgrade ore from the southern region of the state of chihuahua. Thiosulfatecopperammonia leaching of pure gold and.
The ammoniacal thiosulfate leaching process has been used for the extraction of gold and silver. By richard morochove, pcworld practical it insight from tony bradley todays best tech deals picked by pcworlds editors top deals. The gold concentration of the solution was in the range from 2 mgl to 16. Leaching of gold from a free milling gold ore in copper.
The application to different ore types and process options have also been discussed. Gold powder prepared by reduction precipitation from a auci solution was leached using an oxygenated sodium thiosulphate solution 0. Once youve done it, youll be able to easily send the logos you create to clients, make them available for download, or attach them to emails in a fo. Thiosulfate was identified in the 1900s as a lixiviant for the extraction of precious metals in the presence of appropriate additives 18. The application of ammonium thiosulfate for the treatment of copper gold ores has been investigated. Although a low gold recovery of 8283% was achieved in nonammoniacal thiosulfate at elevated temperatures and oxygen partial pressures 19, a recent study has shown the possible application of ironiiiedta thiosulfate thiourea as a leaching agent for gold, to achieve a much higher gold extraction 90% under ambient leaching conditions. Thiosulfate leaching is particularly well suited to stateoftheart resininpulp rip gold recovery technologies thiosulfate leaching is an alkaline process usually operated in the ph 8 to 10 range so there are no concerns with corrosion of equipment in the recovery operation. Using toxic chemicals such as cyanide and mercury in the gold leaching process is one of the main factors that need to be. In superficial leaching experiments of holistic rams a formation of a passive layer was observed, which hindered or slowed. The role of ligands and oxidants in thiosulfate leaching.
The treatment of coppergold ores by ammonium thiosulfate. Ammonium thiosulfate leaching of gold for optimizing the leaching condition in this chapter, optimum leaching conditions for au ex. The kinetics and mechanism of gold leaching in the ammonia thiosulfate copper atscu system have been studied using the rotating electrochemical quartz crystal microbalance reqcm. Metals 2019, 9, 387 2 of 12 the effect of edta, thiosulfate, and cupric ions on silver leaching kinetics. Wo2005017215a1 improved thiosulphate leach process. 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. The current problem of thiosulphate gold leaching is the high reagent consumption, to understand the decomposition chemistry of thiosulphate, solution stability tests were conducted in open and sealed vessek mder ambient temperature. Adobe systems is a software manufacturer that has created many document and multimedia editing programs. Thiosulfate leaching of gold from waste mobile phones ha v.
Thiosulfate leaching of gold is similar to cyanidation. Pdf ammoniacal thiosulphate leaching of gold finds a better substitute as it is nontoxic and environmentally safe as compared to the toxic cyanide. Fundamental aspects of gold leaching in thiosulfate solutions. The new yahoopowered ads for adobe pdf service makes it easy to place payperclick ads in your pdf files. Recovery of gold from thiosulfate solutions and pulps with. Finally, a novel method to recover extracted au ions in ammonium thiosulfate medium was developed. Mineral resources research division, korea institute of geoscience and mineral resources kigam, 92, gwahangno, yuseonggu, daejeon 305350, south korea. This is a pdf file of an unedited manuscript that has been accepted for publication. Development of a new method for gold recovery from waste.
Steven brunt, nalco champion australia glycinecyanide synergies in the leaching of copper gold ores and concentrates 254. The consumption of thiosulfate, however, was largely reduced. This necessitates the use of more ex pensive resin adsorptionion exchange processes to recover the gold from thio sulfate solution. Bits and pieces of information are what is dangerous with any process.
The observed leaching results show that with increasing thiosulfate ions concentration the leaching efficiency increases for both ag and cu. In the leaching test on the reference gold ore, about 93% of gold was extracted. It was found that strongbase resins are superior at accommodating the gold thiosulfate complex compared to weakbase resins, which means strongbase resins have a greater capacity to compete with other anions in leach solutions. This process is beneficial to the gold recovery from leaching solutions using an anion exchange resin. Thio gold is an environmentally friendly and safe alternative to cyanidation in gold processing. To combine pdf files into a single pdf document is easier than it looks.
The processes include subjecting the gold bearing and copperbearing thiosulfate solution to a ph andor temperature adjustment to reduce tetrathionate concentration in the thiosulfate solution prior to contacting with an ion. Ammonium thiosulphate is an alternative gold leaching laaviant used to replace cyanide. In the thiosulfate leaching tests, the effects of the concentrations of thiosulfate, copperii, ammonia, and sulfite on the gold extraction were investigated. Understanding gold thiosulfate leaching system plays a crucial role in order to effectively extract gold, in which the kinetics and equilibrium adsorption of thiosulfate, polythionates, gold thiosulfate and copper onto resin in resinsolution systems are taken into account. Micromechanism study of strengthening effect of copper on.
A study of thiosulfate leaching of gold from carbonaceous ore. To leach a mildrefractory copperbearing gold ore, the authors used a reagent combination of 0. Tessenderlo kerley holds numerous patents for thiosulfate applications. As result of this comparison, thiourea stands out as the most promising alternative gold leaching reagent to cya nide. Thiosulfate leaching to recover gold from ores is known for several decades but extensive researches have been started only for the past two decades. Aug 15, 2020 the oxygen pressure thiosulfate leaching process without the use of ammonia and copper has been successfully used to leach gold from ores ji et al. At present, however, thiosulfate leaching of minerals is only applied commercially in the goldstrike deposit of the barrick gold corporation 8. Depending on the type of scanner you have, you might only be able to scan one page of a document at a time. In the testing, thiosulfate consumption was 30 kgt of ore. A comparison of thiosulfate with cyanide leaching of gold from carbonaceous ore showed that thiosulfate is chemically better and economically more advantageous. Autogenous thiosulfate generation and leaching of gold from refractory sulfide concentrate 242 paul breuer, csiro mineral resources australia. Whether the leaching is performed in stirred tank reactors or heaps, the size and type of equipment needed for a thiosulphate leaching flowsheet is very similar to a conventional cyanide leach. The operation is located in the colorado rocky mountains southwest of denver at an elevation of 10,000 ft 5. The leaching of gold is then accomplished by maintaining a temperature of 5070.
By michelle rae uy 24 january 2020 knowing how to combine pdf files isnt reserved. Effect of activated carbon on the thiosulfate leaching of gold. The research into leaching of gold with thiosulfate as an alternative lixiviant to cyanide has predominantly involved the use of copper in the presence of ammonia which serves as the oxidant. Alternative lixiviants for gold thiosulfate barrick gold introduced thiosulfate leaching circuit that achieved commercial production in q3 2015 and is expected to complete its ramp up by q3 2016. Cyanide alternative leaching reagents for gold recovery. This document has been enriched presented in the imec 2014, with the increase of series v and vi.
Solidification of sulfur and arsenic in gold concentrate. This means it can be viewed across multiple devices, regardless of the underlying operating system. Sgs is a global technical leader in the field of thiosulphate leaching, and our. Thiosulfate leaching of gold ores has great potential to reduce the impact on the environment. Improvement of thiosulfate stability in gold leaching. Thiosulfate leaching offers a number of benefits related to gold recovery yields and environmental concerns. Leaching process involves time consuming stages to reach the total metal dissolution. Understanding gold thiosulfate leaching system plays a crucial role in order to effectively extract gold, in which the kinetics and equilibrium adsorption of thiosulfate, polythionates, gold thiosulfate and copper onto resin in. However, there are concerns about the health and environmental risks of ammonia or ammonium.
The paint program can help you make new image files, but it cannot open document or pdf file. The thiosulfate gold complex formed in thiosulfate leaching is not attracted to carbon so this failure to remove the carbon is no longer an issue. An oversized pdf file can be hard to send through email and may not upload onto certain file managers. I would like to hear the facts,from someone that has used it in a real mining situation. It confirms the possibility of thiosulfate leaching application for silver extraction. It is known that thiosulphate is a metastable species that readily undergoes decomposition in aqueous solutions. Pdf is a hugely popular format for documents simply because it is independent of the hardware or application used to create that file. Jan 02, 2012 lixiviant for gold leaching which efficiently recovers gold. Processes for recovering gold from copper gold ores thiosulfate leaching or gold ores copper catalyzed thiosulfate leaching using ion exchange technology are disclosed. This article explains what pdfs are, how to open one, all the different ways. Read on to find out just how to combine multiple pdf files on macos and windows 10. Chlorination, aqua regia, bromine, thiocyanate, thiosulfate and thiourea leaching.
Fundamental aspects of gold leaching in thiosulfate. Leaching of gold from the waste mobile phone printed circuit. Materials the gold bearing concentrate sample was obtained by the. In a resinin leach system, full gold recovery was also achievable with sufficient resin after 24 h leach with 0. Thiosulfate copperethylenediamine system was found effective in the leaching of gold. Leaching of gold from the waste mobile phone printed. However, the major problem with this leaching method has been the high consumption of reagents. The processes include subjecting the gold bearing and copperbearing thiosulfate solution to a ph andor temperature adjustment to reduce tetrathionate concentration in the. The behaviour of thiosulfate, tetrathionate and sulfate in solution was studied using ion chromatography. Barrick thiosulfate leaching of double refractory ore. Agglomerationheap leaching operations in the precious.
Making a pdf file of a logo is surprisingly easy and is essential for most web designers. Searching for a specific type of document on the internet is sometimes like looking for a needle in a haystack. Ammonium thiosulfate is a noncyanide lixiviant for gold leaching. Thiosulfate leaching appears to be one of the most promising alternatives to cyanidation. Impregnated activated carbon for gold extraction from. Thio gold series products are aqueous thiosulfate solutions that effectively act as lixiviation agents in gold leaching applications.
The presence of silver, lead and zinc can also affect gold extraction 21,30. In this method a weak sodium cyanide solution nacn of 100500 ppm is used. The leaching kinetics was significantly slower than that of the conventional thiosulfate copperammonia leaching. Luckily, there are lots of free and paid tools that can compress a pdf file in just a few easy steps. The authors indicated that the leaching system offers promising opportunities for industrial application.
For this pro pose, the gold leaching reagents are described and discussed in terms of their environmental and economical points of view. An improved thiosulphate leach process for the recovery of gold from ores and other gold bearing materials, characterised in that the leach solution comprises thiosulphate, thiourea or a reagent chemically related thereto, and an oxidant that does not oxidise thiosulphate, the process producing a pregnant leach solution from which gold may be recovered. Tcm leaching is the process of leaching and recovering gold in the presence of tcm traditional leaching process cyanide nacn is the leaching chemical, coconut shell carbon adsorber tcm leaching process no cyanide required calcium thiosulfate cats is the leaching chemical gold leached does not adsorb onto the tcm. You can use the tools in paint to add something to a different document. A method for leaching or dissolving gold from ores or. Gold leaching, thiosulfate, additives, leaching kinetics, thiosulfate stability.
Biooxidationthiosulfate leaching of refractory gold. Gold recovery from electronic waste by pressure oxidation. The gold industry has been seeking alternative reagents for leaching gold from lowgrade ores for the past 25 years. Gold leaching in thiosulfate solutions and its environmental effects compared with cyanide. The role of ligands and oxidants in thiosulfate leaching of gold. The thiosulphate concentration was determined by iodometric titration. Alternative lixiviants to cyanide for leaching gold ores. Leaching of gold and silver from printed circuit boards pcbs with cyanide, nitric acid and thiosulfate has been performed with reaction times greater than 2 hours 6. The effect of concentration of different reagents, applied potential, ph, temperature, and electrode rotating. Thiosulfatecopperammonia leaching of pure gold and pressure. The higher concentration of thiosulphate required leads to higher reagent consumption, which is at least. Associated sulfide minerals in thiosulfate leaching of. Meanwhile, every year, millions of tons of waste are generated worldwide from electrical and electronic products. I have edited this to include some information that may help the forum members in the future, and one in particular.
A leaching process using thiosulfate in an ammoniacal medium to recover the gold contained in these pcbs has also been reported 17. One of the fun things about computers is playing with programs like paint. At the highest thiosulfate ions concentration the leaching recoveries of ag and cu were 60 and 35%, respectively. There are few reports available in the literature on ammoniacal thiosulphate leaching of gold yen et al. The leach was run for 96 hours in a stirred reactor with 19. Colorado gold vat leaching, 1,500 tpd in this operation, the agglomerated feed is leached in large vats rather than in heaps. The effects of some associated minerals on thiosulfate gold leaching were studied through thermodynamic analysis and leaching experiments on composite ore samples containing various minerals and a reference silicate gold ore. A pdf file is a portable document format file, developed by adobe systems. Anodic polarization, cathodic polarization and leaching experiments were included in this study. Thus, the use of thiosulfate with autoclaveprocessed double refractory ores does not result in the loss of the gold complex in the tails. Associated sulfide minerals in thiosulfate leaching of gold. Institute for environmental science and technology, hanoi university of technology hut, 1 dai co viet, hanoi, viet nam. Pdf thiosulphate leaching for gold hydrometallurgy. Jun 19, 2015 the first gold bar produced with the thiosulphate process was poured in late 2014 at barricks goldstrike plant in nevada, usa and operations are ramping up to recover gold from four million.
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