The leaching experiments with iodine, bromine and aqua regia showed the fastest and continuous gold dissolution over time. A significant influence of temperature on gold leaching was...

This paper demonstrates the recovery of valuable metals from shredded Waste Printed Circuit Boards (WPCBs) by bromine leaching. Effects of sodium bromide concentration, bromine concentration, leaching time and inorganic acids were investigated. The most critical factors are sodium concentration and bromine concentration. It was …

A process for recovering gold from a gold-containing raw material, comprising leaching the gold-containing material with an aqueous solution comprising elemental bromine and bromide source to form a pregnant leach solution with the gold dissolved therein; separating said pregnant leach solution from the gold-depleted raw material, removing …

It not only describes chlorination, but also informs on the action of bromine and iodine. (unknown) 8 years ago (unknown) 8 years ago. Like. ... The refractory concentrate and then leach the liberated gold by normal cyanidation processes. And leach the gold out of the concentrate in one step. Some work was done on electrolytic production of ...

The greatest promise for the bromine leach process was with oxidized gold ores. The recovery of gold from oxide ores with bromine was comparable to ... of Gold in a Bromine/Bromide Lixiviant ...

Sodium Cyanide (NaCN) has been used to recover gold from gold bearing ores. This work aims to develop a simulation model of leaching process by using cyanide solvent for the dissolution of gold by ...

open access Highlights • Cyanide-free mild chloride leaching was investigated. • Gold could be recovered even at <520 mV vs. Ag/AgCl in carbon-in …

Gold has mostly been leached out from ores, secondary sources and gold containing spent materials by cyanidation ( Botz et al., 2005, Fricker, 1993, Mudder and …

Probably the best way to leach gold using bromide is preparing an aqueous solution of bromine, with chlorine and hypochlorite playing a key role in the leaching …

Chlorine, bromine, and iodine are well-known lixiviants for leaching gold, as reviewed by Tran et al. (2001). Chlorination was applied extensively in the late 19th …

Chlorine, bromine, and iodine are well-known lixiviants for leaching gold, as reviewed by Tran et al. (2001). Chlorination was applied extensively in the late 19th century before the introduction of the cyanidation process. Bromine/bromide for leaching gold from ores was reported as early as 1846.

Scientists launch 'nano gold rush' by replacing cyanide with cornstarch. EVANSTON, Ill. --- Northwestern University scientists have struck gold in the laboratory. They have discovered an inexpensive and environmentally benign method that uses simple cornstarch -- instead of cyanide -- to isolate gold from raw materials in a selective manner.

The group of chemicals known as halides is composed of the elements fluorine, chlorine, bromine, and iodine. We will ignore fluorine because it does not dissolve gold. The elements listed above are in order of their molecular weights, density, cost, and reactivity. Chlorine is the lightest, cheapest and least reactive while iodine is heaviest ...

Theoretical analysis of sodium carbonate action. OPASL is using pyrite oxidation to release the wrapped gold and leach gold by thiosulfate generated. Pyrite is oxidized in the following formula to produce metastable thiosulfate anion under oxygen pressure alkaline conditions. 4FeS2 + 7O2 + 8OH− + 2H2O = 4Fe (OH)3 + 4S2O32−.

This paper presents experimental evidence that supports the use of bromine/bromide as a potential alternative to conventional cyanidation for gold leaching. …

Similar to bromine, also hydrochloric acid has a low boiling point (45 °C), which would lead to a reagent loss and a slowing down of gold extraction. Figure 11

The bromine/bromide leaching of gold constitutes an alternative that is known since the 19 th century. Leaching rates are higher than with the cyanide technology and provided the problems associated with the high vapour pressure and corrosive nature of bromine are taken care of, the process is also much less toxic. ...

1. A process for recovering gold from a refractory gold ore, comprising the steps of: electrolyzing a mixture consisting of the ore particles and an aqueous bromide solution in an electrolytic cell having anode and cathode, wherein bromine is produced at the anode by oxidation of the bromide, thereby dissolving gold in the aqueous phase; separating the …

In a method for leaching gold from copper sulfides, the sulfide ores are first subjected to leaching of copper, thereby producing a leaching residue having 7.9% or less of the copper content. This leaching residue is mixed with a leach liquor, which contains the chloride ion and ferric ion and has 1.9 or less of pH. Gold and copper can be effectively leached from …

With the development of a low temperature roasting, acidic bromine leaching process by The Minerals Laboratory of BHP Minerals, substantial PGM recoveries from oxide and mixed oxide/sulfide ores are now possible. This patented TML Process for platiniferous oxide ores will yield recoveries of 95% for gold, 85% for platinum and over 65% for ...

The recovery of gold from oxide ores with bromine was comparable to that achievable with cyanide and bromine consumption was reasonable when leaching was conducted at a near neutral pH of ~6.

Iodine forms a very stable gold complex, but it's much more costly than chlorine, and has a loading capacity of only about half of an acidified chlorine leach. Of the 5 halogens, chlorine and bromine have been used with some success in the past for batch leaching, but they also have their problems. Chlorine when used with an oxidizer or as a ...

It was decided to examine the bromine concentration effect on gold dissolution from the autoclave leach residue. However, the gold recoveries were still unsatisfactory (only 61.26% with 2 ml/I of bromine). Higher than 2 ml/I bromine concentrations were not used because higher concentrations would be, from practical …

Adoption by placer gold miners Bromine leaching is a neglected method for recovering placer gold [41], and the author is unaware of any companies, recreational miners or artisanal miners doing so. GOLD RECOVERY BY BROMINE LEACHING. Bromine can dissolve (leach) >90% of gold smaller than about 75, but is too slow for leaching larger …

Results showed that significantly higher gold recovery can be achieved with bromine than with cyanide when leaching gold …

Under the conditions of collective leaching of silver, gold and palladium with a slightly acidic (pH = 1.98) bromine-bromide solution, with a content of 100.8 g · dm-3 of bromide ions, it is ...

However, as Tran et al. explain, the bromide–bromine system is receiving increasing attention, particularly since the Great Lakes Corporation patented its bromine-based gold leaching process, which is based upon a proprietary dibromo-dimethyl hydantoin compound. Gold leaching rates in iodide solutions are also much faster than cyanidation.

Leach & Recover Gold from Black Sands. Black sand may be generally defined as a constituent of "alluvial" gravel consisting mainly of fine particulate grains of heavy, dark colored minerals and rocks. These alluvial gravels, chiefly concentrated by wave, current or surface action, may also contain "eluvial" material that includes black ...

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.

The gold extraction rate for raw gold ore under optimum conditions (0.25 M potassium bromate, 0.08 M ferric chloride, 0.4 M hydrochloric acid, extraction time of 5 …