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, …

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

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 ...

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.

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 …

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 …

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%. …

The kinetics of iodine-assisted chalcopyrite leaching in ferric sulfate media at ambient temperature were studied. A series of leaching tests were carried out to investigate the response of copper extraction from chalcopyrite to variations in the redox potential, total iodide concentration, particle size, and temperature.

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 ...

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 ...

Potassium iodide (ReagentPlus®) was supplied by Sigma-Aldrich, and was used to produce 0.15 dm3 of 4 M KI solutions in 18.2 M qual-Ω ity DI water. For some experiments iodine was added to the ...

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 …

iodine leach processes are well known in the art, a significant problem with prior methods is that they suffer from inefficient recovery and reuse of iodine. Much of the iodine is consumed by the ore body. Since iodine is only 300 times more abundant than gold itself, this relative scarcity can make the use of iodine too expensive for commercially …

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 ...

It suggests that iodide leaching is as much an effective method as iodine–iodide leaching for the extraction of gold from samples containing gold and can potentially reduce reagent cost, …

The dominant organic matter in Haidai leachate were polysaccharides, while the highest iodine specie was iodide (∼90% of total iodine). Several unknown I-DBPs generated …

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.

The model over predicted iodine leaching, results in a weak correspondence between the simulated and the measured results for iodine leaching. ... infiltration time, total leachate collected, and ...

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 iodine leaching from soils. Research reports on the leaching and movement of iodine in soil supplemented with amendment materials using the HYDRUS-1D tool are scanty. The …

Our leaching experiments demonstrate that iodine is relatively stable in acidic solutions for ∼60 min, but nearly half of the iodine can be lost under prolonged …

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 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 ...

open access. Abstract. We investigated changes in iodine ( 129 I) solubility and speciation in nine soils with contrasting properties (pH, Fe/Mn oxides, organic carbon and iodine contents), incubated for nine months at 10 and 20 °C.

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%.

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%.

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 …

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%. The ion-exchange …

In the present work, 13 iodine–iodide leaching tests were performed. The experimental conditions of these tests are reported in Table 2 . The tests were designed to study the effects of various factors, including catalysts size, agitation speed, solution pH, temperature and liquid to solid ratio on the Pt extraction rate and its maximum recovery.

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 ...

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 ...

We investigated changes in iodine (129 I) solubility and speciation in nine soils with contrasting properties (pH, Fe/Mn oxides, organic carbon and iodine contents), incubated for nine months at 10 and 20 °C.The rate of 129 I sorption was greater in soils with large organic carbon contents (%SOC), low pH and at higher temperatures. Loss of …

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 …

Leaching of organic matter and iodine, formation of iodinated disinfection by-products and toxic risk from Laminaria japonica during simulated cooking ... The dominant organic matter in Haidai leachate were polysaccharides, while the highest iodine specie was iodide (∼90% of total iodine). Several unknown I-DBPs generated from the ...

Leaching experiments further confirmed that reducing substances (such as sodium sulfides, ascorbic acids, and fulvic acids) in the soil with low dissolved oxygen (DO) …

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.

The measurement of the total iodide concentration at the beginning and end of a leaching test showed that the total iodide concentration did not change during leaching, meaning that the experimental apparatus was effective in preventing iodine loss via evaporation. 3.3. Effect of different parameters on iodine-assisted chalcopyrite …

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 …

Iodide leaching could serve as an effective mean for recovering gold through the dynamic, thermodynamic and electrochemical assessment. And a series of parameters, such as oxidants selection, the …

To prevent iodine loss during leaching and sampling, a total of seven PTFE bottles with high chemical resistance were used to obtain one leaching curve, each representing one data point in the curve. The experimental results show that the copper extraction increased with increasing redox potential, increasing total iodide …