Thermodynamic and kinetic of iodine–iodide leaching in …
The thermodynamic equilibria and kinetic aspect of gold dissolution in iodine–iodide leaching were studied with emphasis on the effects of pH value and …
Leaching and Adsorption of Gold from Waste Printed Circuit …
Iodine-iodide leaching and activated carbon adsorption processes for recovery of gold (Au) from waste printed circuit boards (WPCBs) were discussed in this paper. A pressure oxidative acid leaching (POAC) was carried out in an autoclave using diluted sulfuric acid (1M H 2 SO 4 ) solution in order to remove high concentrations of …
High-Pressure Oxidative Leaching and Iodide Leaching …
iodine–iodide solution is a highly selective and efficient leaching agent for the recovery of gold from gold ores and WPCBs [21,23–25]. Several decades ago, the first patented process by ...
Non-cyanide Leaching Processes in Gold Hydrometallurgy and Iodine
ABSTRACT Gold leaching in iodine-iodide solution has been intensely researched in 1980s; while due to the high cost, it has not been applied in industry. Currently, as the drawbacks of other … Expand. 19. 1 Excerpt; Save. Hydrometallurgical Processing of Gold-Containing Ore and its Enrichment Products.
Characterization of the solid leach residues from the iodine …
Chalcopyrite dissolution in ferric sulfate media at ambient conditions is slow. The addition of iodide has been found to significantly improve chalcopyrite leaching in the potential range where triiodide (I 3 −) or diiodine (I 2) is the predominant species.In the iodine-assisted chalcopyrite leaching process, elemental sulfur was proposed to be the …
Iodine-assisted chalcopyrite leaching in ferric sulfate …
The iodine-assisted heap leaching of chalcopyrite involves the addition of iodide in ferric sulfate media to accelerate the dissolution of chalcopyrite at ambient temperature. The previous studies using reactor leaching tests identified the solution potential, the amount of iodide added, and temperature as the factors controlling the …
The leaching kinetics of an oxide gold ore with iodide/iodine …
In contrast, gold extraction from the oxide ore in a solution containing 20 g/L iodide and 4 g/L iodine reached 77% in 6 h and 89% in 24 h. With iodate as the oxidant, no gold could be leached in ...
Solution chemistry of iodide leaching of gold
For the solution of initially 0.1 M iodide and 10 mM iodine, substituting the equilibrium concentrations of iodide, tri-iodide and soluble gold iodide AuIy species as 90, 7.25 and 4.8 mM respectively to the Nernst equations, eqs. (3) and (4), yield both El and E2 values of 0.565 V versus SHE.
Iodide—thiocyanate leaching system for gold | SpringerLink
Abstract. The leaching of gold by thiocyanate solutions is performed at pHs between 1 and 2, which allows the use of iron (III) as an oxidizing agent. The mechanism of dissolution of gold by iron (III)-thiocyanate solutions is directly linked with the autoreduction process, in which Fe III is spontaneously reduced to Fe II while oxidizing SCN ...
Iodine enrichment in the groundwater in South China and its
To reveal the influences on iodine leaching from soil to groundwater, batch experiments were designed to investigate the kinetics of iodine migration. In detail, each soil ... It was observed that the injection of oxygen-rich water significantly reduced iodide leaching, with the higher DO concentration (8.0 mg/L) exhibiting a faster oxidative ...
Gold Extraction from an Oxide Ore in Iodine-Iodide …
In contrast, gold extraction from the oxide ore in a solution containing 20 g/L iodide and 4 g/L iodine reached 77% in 6 h and 89% in 24 h. With iodate as the oxidant, no gold could be leached in ...
Figure 4 from Leaching and Adsorption of Gold …
Iodine-iodide leaching and activated carbon adsorption processes for recovery of gold (Au) from waste printed circuit boards (WPCBs) were discussed in this paper. A pressure oxidative acid …
Estimation of Iodine Leaching in Soil Amended …
This study investigated the ability of a HYDRUS 1D model for predicting the vertical distribution of potassium iodine (200 ppm) in soil columns after amendment with five different common remediation …
Non-cyanide Leaching Processes in Gold Hydrometallurgy and Iodine
Non-cyanide Leaching Processes in Gold Hydrometallurgy and Iodine-Iodide Applications: A Review. ... However, leaching by cyanide solutions has a set of substantial drawbacks: process duration, high cost of the reagent, nonadaptability of "stubborn" ores and concentrates, absence of possible regeneration of cyanide solutions …
Leaching and Adsorption of Gold from Waste Printed …
2.2.2. Iodine-Iodide Leaching The experiments for gold leaching from the WPCBs ash sample in iodine-iodide solutions were conducted in a 0.5 L baffled volumetric flask immersed in a thermostatically controlled water bath. Agitation was done by a flat blade impeller. Effects of various important variables such as iodine/iodide concentration, pulp
Recovery of Valuable Metals from Waste Printed Circuit
Iodine-Iodide Leaching. The pregnant leach solution with an initial pH of 2.84 and Eh of 0.58, V derived from the iodine-iodide leaching under the previously specified conditions contains precious metals such as Au, Ag and Pd in appropriate amounts, and some other base metal impurities like Ca, Cu, Al, Pb, Mg, Zn, Fe etc. in …
Gold Dissolution from Ore with Iodide-Oxidising …
2 Altmetric. Metrics. Gold leaching from ore using iodide-iodine mixtures is an alternative to gold cyanidation. This study evaluated the ability of iodide-oxidising bacteria to solubilise gold ...
Iodine/Iodide Leaching of Gold from Black Sand
KI + I2 -->KI3. After gold is leached into the iodide solution (red brown solution), Sodium Hydroxide (NaOH) can be use to reduce the iodine in solution to iodide and precipitate the gold, at this point the solution will go more colorless as the sodium iodide (NaI) is colorless, gold being impure is a black powder. I2 + NaOH -->NaI.
Study on gold concentrate leaching by iodine-iodide
Gold extraction by iodine-iodide solution is an effective and environment-friendly method. In this study, the method using iodine-iodide for gold leaching is proved feasible through thermodynamic calculation. At the same time, experiments on flotation gold concentrates were carried out and encouraging results were obtained. Through optimizing the …
Recovery of gold in iodine-iodide system – a review
Iodide leaching could serve as an effective mean for recovering gold through the dynamic, thermodynamic and electrochemical assessment. And a series of …
Non-Cyanide Leaching Processes in Gold Hydrometallurgy and Iodine
Among them, an iodine-iodide solution is a highly selective and efficient leaching agent for the recovery of gold from gold ores and WPCBs [21,[23] [24] [25]. Several decades ago, the first ...
Eco-friendly and economical extraction of gold from a …
Iodine–iodide leaching is a green non-cyanide gold extraction method (Zhang et al., 2012). Compared with cyanide, iodine and its compounds are nontoxic, …
Iodine Gold Leaching
McGrew proposed the use of an I- containing electrolyte to leach gold ores. An iodine lixiviant is added to an ore containing iodine reducing components. As iodide …
A Potential Alternative for Precious Metal Recovery from …
According to other researchers, a gold leaching yield > 90% should be achievable in iodine-iodide solvent [22, 50]. The low gold recovery can be explained by the consumption of iodide ions by ...
Iodine leach for the dissolution of gold
A process for the hydrometallurgical recovery of gold from materials containing gold comprising leaching the materials with a lixiviant containing iodine. To a solution concentrated with natural salts is added elemental iodine until saturated, whereupon mineral sulfides in the ore zone charged with this solution react with the iodine to form …
Solution chemistry of iodide leaching of gold | Semantic …
ABSTRACT Gold leaching in iodine-iodide solution has been intensely researched in 1980s; while due to the high cost, it has not been applied in industry. Currently, as the drawbacks of other … Expand. 19. Highly Influenced. 10 Excerpts; Save. The nature of gold-iodide adsorption onto coconut-shell carbon.
Leaching of Au, Ag, and Pd from waste printed circuit
In the iodine–iodide leaching process, the appropriate parameter such as leaching time, iodine-to-iodide ratio, S/L, and pH was important for obtaining high dissolution efficiency of Au, Ag, and Pd from (SCWO + HL)-treated PCBs of mobile phone. The optimum iodine/iodide ratio determined the oxidizing and complexation ability for …
Thermodynamic and kinetic of iodine–iodide leaching in …
An iodine-iodide system was investigated as an alternative lixiviant for HNO 3 for leaching precious metals from the end-of-life c-Si photovoltaic (PV) cell. A series of batch experiments were conducted for the optimization of leaching kinetics and thermodynamic equilibrium followed by a life cycle assessment (LCA) using data from …
Eco-friendly and reagent recyclable gold extraction by …
The results show that the initial iodine concentration has a significant effect on gold leaching, and increasing the initial iodine concentration was beneficial to gold …
Non-cyanide Leaching Processes in Gold Hydrometallurgy …
Non-cyanide Leaching Processes in Gold Hydrometallurgy and Iodine-Iodide Applications: A Review: Mineral Processing and Extractive Metallurgy Review: …