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
2.2 Stability of thiosulfate solution 16 2.3 Leaching of gold in thiosulfate system 19 2.4 Research on the kinetics and mechanism 25 2.4.1 Passivation phenomena 25 2.4.2 Kinetics study of gold thiosulfate leaching 27 2.4.3 Mechanism of gold thiosulfate leaching 37 2.5 Additives studies 44 3. EXPERIMENTAL APPROACH 48 3.1 Introduction 48
Thiosulfate leaching can be considered a non-toxic 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 carbonaceous-type ores.
The gold industry has been seeking alternative reagents for leaching gold from low-grade 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. However there are also
Jul 10, 2017· Ammoniacal thiosulfate leaching of refractory oxide gold ore was investigated. According to X-ray fluorescence and fire assay analyses, the ore contained about 33.01 wt% Si, 8.53 wt% Al, 7.26 wt% K, 3.00 wt% Fe, and 2.80 ppm Au.
Before leaching the gold, ore must be crushed and grinded into small particles, usually particle size varies between 30 and 180 μm. Free milling ores are ready for leaching after crushing and grinding whereas refractory ores need pretreatment. It is important to pretreat a refractory ore before leaching to achieve better gold extraction.
researched the direct thiosulfate leaching of gold from refractory ore, and they achieved gold recovery of only 70% (Shen et al., 2013). Li et al. studied the best conditions of roasting and oxidizing refractory gold-bearing sulfur concentrates in the muffle furnace, and the optimized technological parameters for thiosulfate leaching were
In addition to the above associated minerals that consume oxygen, alkali and cyanide, the impurity minerals containing antimony, selenium and the fine particles enclosed by gangue also affect the leaching of gold. In order to effectively improve the cyanidation leaching rate of gold-bearing ores, it is recommended to do gold ore dressing test
Nov 09, 2015· The only smell present during the leach time is ammonia. PH has every thing to do with using thiosulfate. If you let your leach run too long,and let the PH drop too much during run time ,it will then pull in some iron. Run time,PH,and temperature are the keys to using thiosulfate. P.S. All of my observations are with sodium thiosulfate.
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.
Jan 01, 2012· Moore DM, Zhang XR, Li CX, et al. Using thiosulfate as a leach reagents instead of cyanide. Metallic Ore Dressing Abroad, 2005, 42: 5-12.  Heath JA, Zhang XR, Lin S, et al. Anaerobic thiosulfate leaching Research on in situ gold leaching technology. Metallic Ore Dressing Abroad, 2008Ëˆ45: 16-22. 
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 place leaching of oxidied gold deposits. A new SAIMM. A modified in situ leaching method for extracting gold from oxidied gold ores using a non cyanide . sodium thiosulphate and ferric EDTA and iodide and iodine are both capable of extracting high . variable however mafic volcanics and intrusives and iron- . need to consider is the potential impact of bacteria on the
Ammonium thiosulfate is a noncyanide lixiviant for gold leaching However, the major problem with this leaching method has been the high consumption of reagents To leach a mild-refractory copper-bearing gold ore, the authors used a reagent combination of 03M (NH 4) 2 S 2 O 3, 003M CuSO 4 and 3M NH 3 at pH 102 for 24 hours In the testing.
Alternative lixiviants to cyanide for leaching gold ores. One promising alternative to cyanide for the leaching of gold is thiosulfate due to its low toxicity and efficiency in leaching gold from low-grade and carbonaceous Inquire Now; The Metallurgy of Cyanide Gold Leaching An Introduction.
The Development of Eco-Frienly Gold Leaching Reagent. With the increasingly prominent contradictions between economic benefits and environmental protection, the requirements for the development of non-toxic and environmentally-friendly gold-dressing reagents as alternatives to cyanide for leaching gold ores are becoming more and more urgent.
Metallurgical ContentMilling History AmalgamationConcentration of MineralsBulk FlotationSelective FlotationFlotation of Nonmetallic MineralsOrder of Mineral FloatabilityLeaching by Cyanidation Before the event of ore dressing, crude ores were shipped directly to the smelters, or the refineries, with the shipper paying the freight and treatment charges. These charges varied with the type of ore
Heap leaching is a method in which a leaching solution is sprayed with a spray leaching system to selectively leach the useful minerals in the ore and recover the useful mineral from the pregnant liquid flowing out of the heap during the infiltration process. Low-grade gold ore heap leaching is a new gold extraction process developed in the 1980s.