Hydrometallurgical Recovery of Gold from Mining Wastes
Iodine gold leaching can be a promising alternative to cyanide leaching because of its low volatility and hazardousness . ... Science of The Total Environment. 1999; 242 (1-3):3-11. DOI: 10.1016/s0048-9697(99)00372-1; 17. Kinnunen PHM, Kaksonen AH. Towards circular economy in mining: Opportunities and bottlenecks for tailings …
The leaching kinetics of an oxide gold ore with iodide/iodine …
Highlights Two gold ores were subjected to iodide/iodine leaching. The carbonaceous ore showed only 20% gold extraction. Gold extraction from the oxide ore reached 89% in 24 h. A power law rate equation was applied to model the gold extraction kinetics. Gold leaching rate was first order with respect to tri-iodide concentration.
Release behavior of iodine during leaching and …
By calcination, the total iodine was released rapidly in 200-300 °C and 700-1000 °C, and almost released completely at 1000 °C, with a leaching rate of 96.6%.
Distribution, sources, and potential health risks of fluoride, total …
F-and TI were mainly derived from the leaching of fluoride- and iodine-containing minerals by cationic exchange, and NO 3-is mainly derived from nitrogen in the soil (31.7-43.9 %), the use of ammonia fertilizers (24.3-36.1 %), and the discharge of manure and sewage (19.4-31.9 %). Nitrogen in the soil can be an important source of nitrate in the ...
Release behavior of iodine during leaching and calcination …
The forms of the leached iodine were mostly ion-exchange and carbonate-bound iodine under pH 1.8 and water soluble and ion-exchange iodine under pH 3.8, 6.5, and 8.5. By calcination, the total iodine was released rapidly in 200-300 °C and 700-1000 °C, and almost released completely at 1000 °C, with a leaching rate of 96.6%.
Leaching characteristics of iodine in coal
By calcination, the total iodine was released rapidly in 200–300 °C and 700–1000 °C, and almost released completely at 1000 °C, with a leaching rate of 96.6%.
Ion exchange recovery of gold from iodine–iodide solutions
1. Introduction. The use of a solution containing iodine–iodide as a lixiviant for gold was initially reported in various patents for recovering gold from scrap materials (Homic, 1976, Wilson, 1973).Later fundamental studies on this leaching system have been carried out by a number of researchers (Angelidis et al., 1993, Davis and Tran, 1991, …
Solution chemistry of iodide leaching of gold
Meanwhile, to achieve the same 85 % gold dissolution rate, the total charge consumed from TENG is only 1.6 % of that from the DC source, indicating an ultrahigh charge utilization rate. ... Iodine–iodide leaching is an effective and environmentally friendly gold extraction method that is expected to replace cyanidation. However, as the …
Determination of chlorine, bromine and iodine in plant …
Total organic iodine (TOI) is used as an integrative surrogate that reflects the amount of iodinated organics in a water sample and is quantified using a refined method that builds on previous ...
Metals | Free Full-Text | High-Pressure Oxidative Leaching and Iodide
This paper deals with the recovery of gold from waste printed circuit boards (WPCBs) ash by high-pressure oxidative leaching (HPOL) pre-treatment and iodide leaching followed by reduction precipitation. Base metals present in WPCB ash were removed via HPOL using a diluted sulfuric acid solution at elevated temperatures. Effects …
Iodine Leaching Solution
Iodine leaching of gold is a kind of halogen gold extraction method. The stability of the gold iodine complex formed by leaching of the gold reaction ranks only second to the gold cyanide complex [1], and the ligand in the leaching of the gold system remains stable in the range of 0–14 [2]. Hence, this method is expected to replace gold ...
A Potential Alternative for Precious Metal Recovery from …
In this study, selective leaching of gold from PCB was performed in an iodine-hydrogen peroxide (I 2-H 2 O 2) solution system. The effects of different parameters such as iodine concentrations, H 2 O 2 concentrations and solids-% on the gold leaching dynamics were investigated. The results show that increasing solids-% has a negative …
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.
High-Pressure Oxidative Leaching and Iodide Leaching …
electronic equipment (EEE) and account for 3–6% of the total constitution of EEE [6,7]. ... and iodide leaching are described in this section. 2.2.1. Optimization of Iodide Leaching
Eco-friendly and economical extraction of gold from a …
Iodine–iodide leaching is an effective and environmentally friendly gold extraction method that is expected to replace cyanidation. ... 0.02 mol/L ammonium persulfate, 0.1 M potassium iodide, pH 5, 50 g of roasted residue, 150 mL of slurry (total volume), a leaching time of 1.5 h, and a stirring speed of 350 rpm. After completion of …
Cradle-to-gate life cycle assessment of iodine production
Cradle-to-gate total LCIA results per 1000 kg of iodine prill product include a GWP 100 of 1.48E+04 kg CO 2 eq., ... Mining, heap leaching, and iodide production in general contribute to more than 80% of the impacts. Mining has the highest contribution to GWP and EP, whereas iodide production has the highest contribution to AP, POCP, and …
Leaching of organic matter and iodine, formation of …
Leaching of organic matter and iodine, formation of iodinated disinfection by-products and toxic risk from Laminaria japonica during simulated cooking. ... America, can reach around 1.0% of the dry weight and iodide is the dominant iodine species with approximately 90% of total iodine (TI) content [32], [33]. I-DBP …
Iodine-Catalysed Dissolution of Elemental Gold in …
iodine–iodide leaching) or in organic solvents (c), which makes these methods less affordable. Expensive ligands in excess amounts (d) are ... [55–58] the total amount of thiols is dramatically reduced (Figure 1, d).[59] When dealing with complex metal mixtures, sequential dissolution seems like a realistic solution. By first removing the ...
Determination of total and water soluble iodine …
iodine was determined spectrophotometrically at 230 nm. By this method, it was possible to determine the total amount of iodine reaching more than about 1 mg kg -1 in soils. In …
Estimation of Iodine Leaching in Soil Amended with …
The enhancement of iodine retention in soils is currently a major challenge, therefore, the practical purpose of the present study was to overcome the problem of …
Iodide Pressure Oxidation Gold Leaching
The fundamentals of such an iodine leaching at ambient temperature was studied. However, the investigation on the dissolution behavior of gold in iodide solutions at elevated temperatures, such as the case in the system considered here has not yet been reported. ... One piece of high-purity gold square plate with total surface area of 2.95 …
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 temperature on the system. The results of ...
A Review on the Research of Hydrometallurgical Leaching of …
Compared to conventional ferric leaching, the JX Iodine Process consisting of the irrigation of ferric iron and low-concentration iodide solutions in the column leaching test also indicated that the effectiveness of the addition of ... the reaction time is 1 h. In addition, there are the Total Pressure Oxidation process and the Sherritt ...
Estimation of Iodine Leaching in Soil Amended with Organic …
The model over predicted iodine leaching, resulting to a weak correspondence between the simulated and the measured results for iodine leaching. ... Total carbon, or ganic carbon, and organic ...
Release behavior of iodine during leaching and …
By calcination, the total iodine was released rapidly in 200–300 °C and 700–1000 °C, and almost released completely at 1000 °C, with a leaching rate of 96.6%. …
Speciation of iodine (127I and 129I) in lake sediments
The solution, containing extracted iodine, was separated from the sample by centrifugation. Iodine in the residue was extracted by alkali fusion in a ceramic crucible for one-time use, followed by water leaching [12]. An aliquot from each step was set aside for total iodine measurement.
Iodide-assisted leaching of chalcopyrite in acidic ferric sulfate media
The addition of potassium iodide into the leaching media led to a decrease of activation energy from 81.4 to 33.8 kJ/mol. ... total iodide concentration (50–200 mg/L), particle size (53–90 μm), and temperature (25–45 °C) on chalcopyrite concentrate leaching. PTFE bottles were used to prevent iodine loss via evaporation and iodine ...
Iodine enrichment in the groundwater in South China and its
A total of 16 groundwater samples were obtained on Nov. 30, 2017, from the Pearl River Delta region, Guangdong Province, China, using a sampler inserted 0.5 m below the groundwater table. ... To reveal the influences on iodine leaching from soil to groundwater, batch experiments were designed to investigate the kinetics of iodine migration. In ...
A Study of the Electrodeposition of Gold Process in Iodine Leaching
Authors: This paper mainly discusses electrodeposition of gold from iodine leaching solution through single-factor testing and explores the influence of gold concentration in catholyte, mass ...
Release behavior of iodine during leaching and calcination of
The forms of the leached iodine were mostly ion-exchange and carbonate-bound iodine under pH 1.8 and water soluble and ion-exchange iodine under pH 3.8, 6.5, and 8.5. By calcination, the total iodine was released rapidly in 200-300 °C and 700-1000 °C, and almost released completely at 1000 °C, with a leaching rate of 96.6%.
