Abstract. Drawing on recent experimental and commercial developments, this review reappraises potential substitute leach reagents for cyanide in the gold mining …

The thiosulfate-based gold leaching system may be realistically used in practice if an overall leaching-recovery process with a reasonable gold recovery and …

of gold from both primary and secondary sources which are promising for implementation on industrial scales. These two new methods are (i) simultaneous leaching and solvent …

Farzaneh Sadri & Ahmad Ghahreman. 54 Accesses. Explore all metrics. Abstract. The application of pressure oxidation (POX) followed by thiosulfate gold …

Introduction to Gold and Silver Leaching. The cyanide leaching process is the most important method ever developed for extracting gold from its ores. The early development of the process is attributed to a Scotchman, John Stewart Mac Arthur, in collaboration with the Forrest brothers. The method was introduced into South Africa in …

Gold leaching tests show that approximately 50% of gold can be extracted easily using cyanide generated in cassava solution in 24 h. Based on what results show, a 10% reduction in the S:L ratio, which means adding more "manipueira" in the leaching process with the same amount of ore, contributed to a 10% increase in gold recovery in …

A gold ore sample originated from an epithermal deposit with a composition shown in Table 2 was used as a feed material in the leaching experiments. X-ray fluorescence and inductively coupled plasma optical emission spectrometry (ICP-OES; Thermo Scientific iCAP 6000, USA) were used to determine the chemical composition of …

Taking a low-grade oxidized gold ore containing carbon and arsenic as an example, the leaching test was carried out when the grinding fineness -0.074 mm accounted for 95%, the slurry density was 33% and pH value was 12, the gold leaching rate kept 81.48% when the leaching time was 24 hours, 36 hours and 48 hours …

Combining sulphide oxidation and gold leaching using an autoclave and a mixture of O 2 –HCl–NaCl yielded high gold recoveries (> 90%) as reported by Pangum and Browner (1996). This could only be achieved when > 90% of sulphide is oxidised and at a solution potential Eh > 0.8 V. The best condition for subsequent leaching of gold is 20 …

This review aims to provide an up-to-date evaluation of thiourea-gold leaching studies from electronic waste, with emphasis on the recent progression from …

Th e gold leaching reaction by thiosulfate without additives is shown in Eq. (4). 4Au + 8S 2 O 3 2-+ O 2 + 2H 2 O → 4Au(S 2 O 3) 2 3-+ 4OH-(4) Thiosulfate and oxygen act as ligands and oxidants ...

The effect of thiocyanate concentration on the rate of gold leaching was examined in the thiocyanate concentration range of 0.05–0.2 M.The results are presented in Fig. 2.It is understood from Fig. 2 that the initial rate of gold leaching is quite slow and most interestingly, almost insensitive to thiocyanate concentration (0.05–0.2 M). The rate …

4. Strong Applicability: Suitable for heap leaching, basin leaching and CIP process of oxidized gold and silver ore. The scale can be large or small and is more suitable for large scale heap leaching. 5. High leaching rate: it can effectively leach gold ions and can achieve faster with a higher recovery rate than using sodium cyanide. 6.

Gold extraction processes from both primary and secondary sources have changed little over the past centuries with cyanide remaining the preferred leach reagent used in 90% of gold mines, while aqua regia, which has been used for more than 1000 years, remains an unmatched gold leaching reagent for secondary sources.

Gold decoration of chalcopyrite surfaces has been shown to stimulate surface enhancement of Raman scattering and this enables oxidation products, undetectable using normal Raman spectroscopy, to be investigated. Electroless deposition, sputtering and evaporative deposition facilitated SERS. In situ potentiodynamic investigations …

3.2. Gold Bioleaching from Sulfide Ore Concentrate and e-Waste by R. tolerans and R. mucosus. Gold leaching yields from gold ore concentrate and e-waste by R. tolerans and R. mucosus were as shown in Figure 1 and p-values from two- and one-way ANOVA were as shown in Table 3 and Table 4, respectively.

The leaching behavior of gold from an oxide gold ore using copper–tartrate–thiosulfate solutions has been investigated. Experimental parameters, including temperature, initial pH, and concentrations of copper tartrate and thiosulfate, were systematically studied. The capability of gold leaching using copper–tartrate–thiosulfate …

Thiourea leaching of gold from waste electronics has been extensively studied and shows good potential for industrial application. However, most of the …

Some sedimentary minerals have attractive contents of gold and silver, like a sedimentary exhalative ore available in the eastern of Hidalgo in Mexico. The gold and silver contained represent an interesting opportunity for processing by non-toxic and aggressive leaching reagents like thiosulfate. The preliminary kinetic study indicated that the leaching …

Cyanide-free mild chloride leaching was investigated. •. Gold could be recovered even at <520 mV vs. Ag/AgCl in carbon-in-chloride-leach mode. •. Copper was a stronger oxidant than iron in gold leaching. •. Gold was oxidized by in-situ dissolving impurities. •. Seawater contains enough chlorides to dissolve gold.

This study was carried out on a finely disseminated gold-bearing ore from Kaymaz, Turkey. The main objective was to determine the mechanism of reaction between thiourea and Fe 3+ in the thiourea leaching of gold. Thiourea consumption levels were also examined during the leaching operations for different leaching parameters, i.e., molar …

Energy saving and environmental protection: The gold mine leaching agitation tank uses a high-efficiency motor to reduce energy consumption; at the same time, the closed mixing design reduces ...

Their results indicated that in comparison with Glu, Gly was greatly more capable of gold leaching, and the highest achieved leaching recovery was about 12% after 24 h. Moreover, it was concluded that potassium permanganate was a more effective oxidant than hydrogen peroxide for amino acid in gold leaching (Perea and Restrepo, …

The application of pressure oxidation (POX) followed by thiosulfate gold leaching is an efficient method used to extract gold from double refractory gold ores containing both sulfide and carbonaceous matter. This process is expected to result in high gold recovery rates, as it liberates gold from sulfides and eliminates the preg-robbing …

The use of thiourea as an alternative lixiviant to gold cyanidation for processing gold-bearing ores or concentrates was first developed by Soviet metallurgists in the 1940s. However, the interest for thiourea leaching of gold mainly came during the 1980s and 1990s to establish a parallel process. The chemistry of thiourea is simpler than ...

Weinberg College. EVANSTON, Ill. --- Northwestern University scientists have struck gold in the laboratory. They have discovered an inexpensive and …

2.1 Cyanide leaching. Cyanide is a cheap but highly toxic reagent that is very effective in leaching gold from low-grade minerals and mining wastes. Therefore, …

Gold leaching with thiourea has the advantages of fast speed (four to five times faster than that of cyanide leaching) and a high leaching rate for refractory gold …

When the cyanide process was first introduced its application was confined to leaching, that is, treatment by percolation. By this method only such material could be worked as was sufficiently granular in texture to allow the necessary amount of solution to percolate through it in a reasonable time. By crushing the ore dry, it is ...

An Experimental and DFT Study on Using the Thiosulfate

This study aims to comprehensively investigate the role of glycine (GL) in gold dissolution with thiosulfate (TS), utilizing both experimental and density functional theory (DFT) approaches. Three different leaching systems, namely AM–TS–Cu2+, GL–TS–Cu2+, and AM–GL–TS–Cu2+, were examined and compared using the …

A Review of Thiosulfate Leaching of Gold: Focus …

Thiosulfate leaching is a promising alternative to cyanidation, and the main hindrances for its wide commercial application are the high thiosulfate consumption and the difficult recovery of …