Despite its popularity, the sodium cyanide method or cyanidation
is highly controversial due to its toxicity.
Field observation of local trees was carried out in September 2013 at areas adjacent to the tailing disposal area of a cyanidation
plant at Sekotong District of West Lombok, Indonesia (115[degrees].
5] showed that only 5-10% of the gold was recovered through the mercury amalgamation process, whereas 90-95% can be recovered through the cyanidation
But with cyanidation
well-entrenched in the industry and regulators looking the other way, these alternatives face an uphill battle in gaining widespread adoption.
Halide systems were used for gold dissolution before the inception of cyanidation
The majority of the samples were sieved in the laboratory into six size fractions and the coarser fractions were analysed for gold by cyanidation
which should extract all the oxidised gold in the sample and by fire assay which analyses total gold.
STUDY OF CHEMICAL METHODS FOR CYANIDE REMOVAL FROM CYANIDATION
WASTE COMING FROM THE GOLD VEIN EXTRACTION PROCESS IN THE DEPARTMENT OF NARINO
The results are based on cyanidation
of porphyry and stockwork style gold mineralized material, and include gold recoveries of 90 percent for oxide, 80.
2]) and arsenopyrite (FeAsS) minerals are oxidized to liberate gold which can be efficiently recovered in the subsequent cyanidation
Gold recoveries following cyanidation
of the bacterial oxidation residue are running in excess of 97% using the current stockpiled concentrate feed.
A key step in dragging the gold business into the modern era was taken in South Africa in 1889, when the cyanidation
process was developed to recover gold from mountains of low-grade ore.
Tests on Palokas drill core have demonstrated excellent gold extraction of between 95% and 99% from a combination of gravity separation and conventional cyanidation
In Sekotong artisanal gold mining area, in addition to amalgamation with mercury (Hg) which is the common method used by the ASGM miners, there was a cyanidation
processing to separate the gold from the soil.
Tailings from the cyanidation
testing were examined by electron microscope and roughly two-thirds of the remaining gold was found to be encased in sulphide and one-third in silicate, preventing exposure to the cyanide solution at the 75 micron grind: possible solutions to increase the gold recovery to over 90% include ultra-fine grinding (perhaps after initial rougher floatation concentration as above to reduce the bulk for ultra-fine grinding), bio-leaching and pressure leaching.
First Majestic Silver Corp (TSX: FR)(PINK SHEETS: RMSF) (FRANKFURT: FMV) (WKN: A0LHKJ), a Canada-based company that explores for silver resources in Mexico, has announced construction of a new cyanidation
circuit at the La Encantada Silver Mine, located in Coahuila Mexico.