Furthermore, an increase in reactant concentration and leaching time is reported to have a positive impact on metal leaching yield [43,44]. Therefore, parameter optimization was conducted, as shown in Table 2. As expected, the leaching yield of copper increased significantly from 63.5 wt.% to 97.7 wt.%. ... A gold leaching yield of −3.5% …

This study aimed to recover copper and gold from a waste printed circuit board (WPCB) using monosodium glutamate (MSG) supplemented with a clean oxidizer(s) under 30 °C, 150 rpm, and an …

Fe (III) has been used as an oxidant in the leaching process, hydrogen peroxide (H2O2) has been confirmed to be a more suitable alternative oxidant due to its ability to yield a high percentage of Au in solution [25]. Although thiourea leaching has been propounded in gold recovery from sulfide gold ore, the studies are still limited [44,45].

The effects of ultrasound on gold leaching in conventional conditions and secondary leaching of cyanide tailings were also investigated. Reaction kinetic models were further built to analyze the influence of ultrasound on reaction of gold leaching. ... aluminium, calcium, potassium and sodium. The gold content is 44.84 g/t. Sodium …

The leaching efficiency of gold increased by about 3.44% in the presence of 500 g/t lead nitrate. It has been concluded that increasing the dissolved oxygen in the cyanide solution reduces the lead nitrate consumption up to 55% due to a reduction in sulfide ions in the solution, preventing the formation of a passive layer. 25

Gold Leaching Process. Many opportunities exist throughout the world for small cyanide plants, possibly using a Gold Leaching …

increase 2.5 - 4 % compare to average gold extraction in 2012. This successful project will be utilized over 300,000 dmt ore/year. 1 Introduction Cyanidation process or leaching of gold ore in aerated alkaline slurry has been the dominant process in gold extraction for more than a hundred years. Significant

However, gold leaching kinetics was slightly better at lower solids content. It was indicated that ... 1.11 10.10 2.26 3.34 7.44 0.05 0.01 0.015 7.51 21.3 2.10 80 80 50. Minerals 2022, 12, x 3 of 13 .

fast gold leaching speed, non-toxic, insensitive to impurities and no corrosion to equipment[2]. Especially ... Silver gold deposit 47.51 42.44 Total 95.88 96.05 Lianshengti gold Natural gold 1.19 1.24 Silver gold deposit 1.35 1.25 Total 2.54 2.49 Inclusion gold Natural gold 0.45 0.47 ...

In this research, cyanide and chloride–hypochlorite leaching of gold from a pyritic concentrate (particle size: −75+53 µm, gold content: 27.15 g/t) were compared. It was shown that only 13.6 % of … Expand

It was found that complete leaching of gold is achieved from fractions of raw materials with a particle size d = 90–180 µm and d = 180–350 µm, containing 277 ppm and 67 ppm of the gold, respectively, at an experiment duration (tex) of 2 h, a current density (i) of 0.66 A·cm−2, and a solid/liquid (S/L) ratio of 8.6 g·L−1. ...

Heap leach gold recovery techniques are employed at Ortiz. Caustic cyanide solutions are sprayed onto crushed rock piles, dissolving the metallic gold from within the rocks and carrying it out as a 'pregnant' …

Gold leaching is an important process to extract gold from ore. Conventional alkaline cyanide process and alternative nontoxic lixiviants including thiosulfate, thiourea, thiocyanate, and halogen have been widely investigated. However, density functional theory (DFT) study on the gold complexes Au(CN)2−, Au(S2O3)23−, Au[SC(NH2)2]2+, …

The Witwatersrand is a 2.9–2.8 Ga sedimentary basin located on the Kaapvaal Craton (Fig. 1) 1.The Witwatersrand basin together with the gold reefs from the Venterdorp and Transvaal supergroups ...

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 …

Gold leaching from ore using iodide-iodine mixtures is an alternative to gold cyanidation. ... allowing for excellent recovery of the reagent and reducing the cost of the process 44. Bioleaching ...

The leaching efficiency of gold in the polysulfide system reached 96.8%. This process has proved to be a promising alternative for efficient and environmentally friendly extraction of gold from the refractory gold ore. ... [44,45,46]. The detected sulfur in the pressure oxidation leaching residue is mainly from the oxidation of sulfur ions in ...

For this propose, the gold leaching reagents are described and discussed in terms of their environmental and economical points of view. As result of this comparison, thiourea stands out as the most promising alternative gold leaching reagent to cyanide. ... [22], [44] (10) A gold extraction rate of 99% can be achieved at optimal conditions ...

A study was carried out to process a sulfide mineral concentrate from Norwest of Mexico containing 97 g/t Au, 0.15% Cu, and 15% Fe. An oxidative acid pretreatment was investigated using ferric sulfate as oxidant, followed by leaching of gold with sodium cyanide. Scanning electron microscopy, SEM-EDS, and X-ray diffraction, …

Scientific Reports - Kinetic Investigation and Dissolution Behavior of Cyanide Alternative Gold Leaching Reagents. ... the passive layer is soluble and enables further gold leaching 41,42,43,44.

Gold leaching using thiourea (0.4 M thiourea, pH 1.5, 3 h) following pretreatment using HCl and Citrate and no pretreatment, M. Reprinted with perimission from [66]

Unlike the thiosulfate system, the passive layer is soluble and enables further gold leaching 41 – 44. Besides pure gold samples, also a gold-silver specimen was …

The electrochemical models for copper-catalytic mechanism of gold leaching with glycine-thiosulfate (a, b: pH 6.44–9.30, c, d: pH 9.30–11.77). When the pH of copper-glycine-thiosulfate solutions is in the range of 9.30 to 11.78, Cu(C 2 H 4 NO 2 ) 3 − in solution acquires electron on the cathodic portion of gold surface and is directly ...

The leach system remains alkaline throughout both stages of processing. In the two-stage glycine leaching system, gold, silver, zinc, lead and copper recoveries were 92.1%, 85.3%, 98.5%, 89.8%, and 99.1% respectively. ... It is reported that the annual amount of E-waste generated worldwide has reached 44.7 million tons/year in 2016, with …

Thereafter, some insights into the mechanism of gold leaching in alkaline sulfur-containing solutions were presented from different aspects, including thermodynamics analysis, electrochemical dissolution, and leaching kinetics. ... 44. doi: 10.1016/j.hydromet.2017.04.006

The high thiourea concentration in conducted trials facilitate the reagent decomposition. Unlike the thiosulfate system, the passive layer is soluble and enables …

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 presents the novel idea of a cyanide-free leaching method, i.e., glycine-ammonia leaching in the presence of permanganate, to treat a low-grade and copper-bearing gold tailing. Ammonia played a key role as a pH modifier, lixiviant and potential catalyst (as cupric ammine) in this study. Replacing ammonia with other pH …

Thereafter, some insights into the mechanism of gold leaching in alkaline sulfur-containing solutions were presented from different aspects, including thermodynamics analysis, electrochemical dissolution, and leaching kinetics. ... 44. Article CAS Google Scholar A.D. Bas, E. Ghali, and Y. Choi, A ...