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thiourea gold leaching ph

Thiourea–thiocyanate leaching system for gold -

The effects of initial concentrations of ferric, thiourea (Tu) and thiocyanate as well as temperature and pH on gold leaching rates were studied. An initial gold leaching rate in the order of 10− 9 mol cm − 2 s − 1 was obtained at 25 °C, which was higher than rates obtained when either ferric–thiocyanate or ferric–thiourea solutions were used ...

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Analysis and Prediction of the Thiourea Gold Leaching ...

The thiourea (TU) leaching of gold from refractory ores can be considered an alternative to cyanidation. However, the high reagent consumption causes an increase in cost, which seriously limits its use. In order to effectively reduce the TU consumption, it is necessary to analyze the influencing parameters of gold recovery and TU consumption and apply them to the prediction of the TU leaching ...

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Thiourea leaching gold and silver from the printed

2012-6-1  The effect of reaction temperature on the leaching rate of gold and silver was investigated at the conditions of thiourea mass concentration 24 g/L, Fe 3+ concentration of 0.6%, pH 1.00, and the results were shown in Fig. 5.

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Gold Metallurgy and Leaching Process

2015-6-24  Gold and Silver Leaching. For Gold and Silver, the most common leachants used are Na or K cyanides in the presence of oxygen, Thiourea (NH 2. CS.NH 2), also in the presence of oxygen, or Ammonium polysulphide (NH 4) 2 Sx, especially for Gold. Optimum physical conditions for cyanidation are: Maximum temperature of 85 o C, Operating ph range of 9.5 – 11.5

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Use of Thiourea Leaching During Gold-Containing

2019-11-6  In Tadzhikistan the volume of gold-containing waste converted to gold is 18 tons. This waste is products of amalgamation and cyaniding processes., and with respect to end component content they may be classified as a very rich type of raw material since they contain 1.7–8.5 g/ton of gold, whereas the average gold content in ores extracted for processing in one of the richest deposits of the ...

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Response of low-grade gold ore to cyanidation and

2019-11-23  (2019). Response of low-grade gold ore to cyanidation and thiourea leaching. Particulate Science and Technology: Vol. 37, No. 1, pp. 86-93.

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Response of low-grade gold ore to cyanidation and

2019-11-23  ABSTRACTIn this study, leaching tests were conducted on representative samples provided from Hamze-Qarnein gold deposit with grade of 0.8 ppm using cyanidation and thiourea leaching. Effective para...

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A Method for Leaching or Dissolving Gold from Ores or ...

2009-1-1  cal processes. The optimized leaching conditions are usually a concentration of lixiviant of 0.1 moldm–3 NaCN. Enough NaOH must be present as neutralizer to maintain alkaline conditions at a constant pH of 11. Several reagents can be used in the dissolution of gold metal from electronic and precious metal scrap.8 Among them,

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Leaching behavior of palladium in thiourea/acid

1996-8-1  Xie, X., Meng, X. Han, K.N. Leaching behavior of palladium in thiourea/acid solutions. Mining, Metallurgy Exploration 13, 119–123 (1996). https://doi.org/10.1007/BF03402731. Download citation. Received: 15 February 1995. Revised: 15 February 1996. Published: 01 August 1996. Issue Date: August 1996. DOI: https://doi.org/10.1007/BF03402731

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CHLORIDE HYPOCHLORITE OXIDATION AND LEACHING

2012-10-4  C, at least 200 g/dm3 calcium hypochlorite is required to achieve high potential values for the gold leaching. Increasing the sodium chloride concentration from 100 to 200 g/dm3 resulted in an increase in the sulfide oxidation rate as well as the extent of extracted gold. Under optimum conditions 200 g/dm3 calcium hypo-chlorite, initial pH = 11 and 200 g/dm3 sodium chloride), the recovery of gold

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Analysis and Prediction of the Thiourea Gold Leaching ...

The thiourea (TU) leaching of gold from refractory ores can be considered an alternative to cyanidation. However, the high reagent consumption causes an increase in cost, which seriously limits its use. In order to effectively reduce the TU consumption, it is necessary to analyze the influencing parameters of gold recovery and TU consumption and apply them to the prediction of the TU leaching ...

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(PDF) An innovative thiourea gold leaching process ...

An innovative thiourea gold leaching process. Hydrometallurgy 48 Ž1998. 113–124 An innovative thiourea gold leaching process S. Ubaldini ) , P. Fornari, R. Massidda, C. Abbruzzese Istituto per il Trattamento dei Minerali del C.N.R., Via Bolognola 7, 00138 Rome, Italy Received 10 July 1997; accepted 6 November 1997 Abstract The aim of this ...

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Response of low-grade gold ore to cyanidation and

2017-6-23  The acidic leaching using thiourea, required more chemical reagents and maximum gold recovery of 90.48% was achieved with thiourea consumption, leaching time, and pH equal to 13.32 kg/t, 5 h, and 1.7, respectively.

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Dissolution Behavior of Gold in Alkaline Media Using

2018-12-28  The dissolution of gold in thiourea solutions was reported for the first time in 1941, and it was continued in 1960 . It has been reported that gold dissolves [1] more efficiently with thiourea in acid than in alkaline solution. Thiourea is un-stable above pH = 4.3, and its degradation is also caused by oxidation. Thiourea

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Recovery of Gold from Pregnant Thiourea Leaching

Aim of this research is to investigate the ability of synergist system of D2EHPA-isodecanol to recover gold from thiourea leaching solution. Synergistic extraction was introduced to replace single extraction due to enhance the extraction efficiency of heavy metal such as gold, silver copper and etc. In order to improve extraction efficiency, di-(2ethylhexyl) phosphoric acid (D2EHPA) was mixed ...

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Response of low-grade gold ore to cyanidation and

2019-11-23  ABSTRACTIn this study, leaching tests were conducted on representative samples provided from Hamze-Qarnein gold deposit with grade of 0.8 ppm using cyanidation and thiourea leaching. Effective para...

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TECHNICAL NOTE COMPARATIVE CYANIDE AND

2021-6-11  assayed. The results indicate that thiourea leaching performs (96.5% extraction at 16 hours) better than (96% extraction at 24 hours) cyanidation. Leaching The gold leaching cells were made of glass and plastic, with a 10 litre capacity at room temperature. The tests were made with ore crushed carefully to -2000 microns at the pH of desired level.

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DISSOLUTION OF GOLD WITH CYANIDE REPLACING

2014-9-8  pH Chloride Thiocyanate Thiourea Cyanide Ammonium thiosulfate Bisulfide Iodide Ammonia Bromide Hypochlorite Fig. 1. Potential-pH diagram showing typical operating windows for gold lixiviants (after Aylmore, 2005) In leaching of gold a complexing ligand and oxidant are needed. Dissolution of gold in cyanide solution is shown in Eq. 1.

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Mechanism of gold dissolving in alkaline thiourea

2007-8-1  Reaction mechanism of gold dissolving in alkaline thiourea solution was studied by electrochemical methods, such as cyclic voltammetry, chronopotentiometry, AC impedance, linear sweep voltammetry. Apparent activation energy of anodic process of gold electrode dissolving in alkaline thiourea solution is 14.91 kJ/mol. Rate determining step is the process of gold thiourea complex

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Optimizing and evaluating the operational factors ...

2015-12-8  Therefore, the optimum pH for leaching should be derived. Figure 6 shows the response surface of gold recovery ((a) contour plot; (b) three-dimensional plot) as a function of the particle size and NaCN concentration at the centre levels. It is obvious that the high gold recovery is achieved at the centre level of NaCN. It is also found that ...

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Response of low-grade gold ore to cyanidation and

2017-6-23  The acidic leaching using thiourea, required more chemical reagents and maximum gold recovery of 90.48% was achieved with thiourea consumption, leaching time, and pH equal to 13.32 kg/t, 5 h, and 1.7, respectively.

Read More
Response of low-grade gold ore to cyanidation and

2019-11-23  (2019). Response of low-grade gold ore to cyanidation and thiourea leaching. Particulate Science and Technology: Vol. 37, No. 1, pp. 86-93.

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"Thiourea-thiocyanate Leaching System For Gold" by

The leaching of gold in thiourea-thiocyanate solutions has been studied by the rotating-disc technique using ferric sulfate as oxidant. The effects of initial concentrations of ferric, thiourea (Tu) and thiocyanate as well as temperature and pH on gold leaching rates were studied. An initial gold leaching rate in the order of 10− 9 mol cm− 2 s− 1 was obtained at 25 °C, which was higher ...

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2001-Study on mechanism of gold leaching by thiourea in

2015-4-2  Hu Y, Guo G, Qiu G. Study on mechanism of gold leaching by thiourea in the presence of sodium sulphite[J]. Journal of Central South University of

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Response of low-grade gold ore to cyanidation and

2019-11-23  ABSTRACTIn this study, leaching tests were conducted on representative samples provided from Hamze-Qarnein gold deposit with grade of 0.8 ppm using cyanidation and thiourea leaching. Effective para...

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Studies on thiourea leaching of finely-divided gold ores

Laboratory leaching experiments were conducted to ascertain the effectiveness of acidic solutions of thiourea, CS(Nh2)2, for dissolving gold from finely disseminated gold ores. The ores tested were from the Chipmunk orebody of the Northumberland mining district in Nye County, Nevada, USA, and carbonaceous ore from the Carlin orebody in Eureka ...

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Hydrometallurgical Recovery of Gold from Mining

2020-11-11  The pH of the solution, leaching potential, ferric sulfate concentration, thiourea concentration and leaching time are critical parameters for the leaching efficiency . The optimum conditions for thiourea leaching can be achieved by using an appropriate quantity of oxidant to ensure the oxidation of 50% of the thiourea to formamidine disulfide.

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Response of low-grade gold ore to cyanidation and

Gold recovery and reagent consumptions (lime, cyanide, thiourea, ferric sulfate, and sulfuric acid) were measured under different leaching conditions. The results showed that cyanidation method was efficient with 95.21% gold recovery with following conditions: d80 = 63 µm, pH 10.5, cyanide consumption of 1.23 kg/t, and 12 h cyanidation time.

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Cyanide and Other Lixiviant Leaching Systems for

2018-6-6  Neutral lixiviant systems (pH 5-9)include thiosulphate, halogens, sulphurous acid, and bacteria plus natural organic acids as the ligand. Oxygen is the normal oxidant and either Au(I) or Au(III)complexes are formed. Acid leaching systems (pH ⩾ 3)may contain thiourea, thiocyanate, chlorine, aqua regia, or ferric chloride.

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生物预氧化—酸性硫脲浸金联合工艺-Combined Process of ...

The factors affecting the leaching of gold with thiourea were studied experimentally. The optimum leaching conditions of thiourea under this system were obtained as follows: temperature 25 ℃, pH 1.5, liquid-solid ratio 5:1, thiourea concentration 25 kg/t, leaching

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