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from the dissociation of the complex is used to leach gold from the ore. The stepwise dissociation of cyanide from coppercyanide complexes can also be used to leach gold from a variety of oxide and sulphide ores. The copper cyanide''s fourth ligand readily dissociates at low cyanide concentrations for use in gold leaching.
It is wellknown that metallic minerals such as chalcopyrite or pyrite are pregrobbing (K. L. Rees et al., Pregrobbing phenomena in the cyanidation of sulphide gold ores, Hydrometallurgy 58, 2000, pp. 6180, stating that chalcopyrite was shown to be very strongly pregrobbing.
Biological Oxidation Of Sulphides In Gold Ore. A sulphide ore containing gt gold most of which finely disseminated in pyrite, was subjected to twostage processing for extracting these precious first stage was connected with liberation of the gold and silver from the sulphide matrix as a result of the sulphide oxidation by means of acidophilic chemolithotrophic bacteria.
inproceedings{Cetin2017BottleRT, title={Bottle Roll Testing for Cyanidation of Gold Ores: Problems related to Standardized Procedures on DifficulttoProcess Ores}, author={Mir Can Cetin and N. Altun and M. U. Atalay and K. Buyuktanr}, year={2017
The Musselwhite Mine in Canada processes a free milling gold ore at /t Au and % pyrrhotite. A laboratory investigation was conducted to improve cyanidation. The pyrrhotite was determined to be 50% monoclinic and 50% hexagonal. A leach using 8ppm dissolved oxygen yielded only % gold extraction with a /t NaCN consumed. The addition of lead nitrate, directly to the leach
The goldadsorbing properties of a wide variety of minerals, ranging from copper sulphides to clay silicates and quartz, were examined. Experiments simulating conditions in cyanidation plants
It competed with activated carbon to remove the majority of gold from solution. Pyrite was also strongly pregrobbing, and in cyanide deficient solutions adsorbed the majority of the gold in preference to activated carbon. The degree of adsorption onto the ore or the activated carbon was a function of the kinetics of the adsorption process.
Introduction Pregrobbing is the phenomenon whereby the gold cyanide complex, 2, is removed from solution by the constituents of the ore. The pregrobbing components may be the carbonaceous matter present in the ore, such as wood chips, organic carbon, or
sulphide gold ores. The sulphide minerals were partially decomposed in the pretreatment process and thiosulphate consumption was reduced during leaching. Gold extraction in M ammonia and M thiosulphate solution after 24 h increased from 69% without pretreatment to 81%, 84%, 90% and 94% after 1, 3, 7 and 22 h of pretreatment.
oxidized deposits (heap leach), lowgrade sulphide ores (cyanidation, CIP, CIL) and refractory gold ores (autoclave, biological decomposition followed by cyanidation). 3. A combination of pyrometallurgical (roasting) and hydrometallurgical route is used for highly refractory gold ores (carbonaceous sulphides, arsenical gold ores) and the
The leaching and adsorption behaviour of gold ores. the effect of copper cyanide on gold leaching from oxide and sulphide ores 110 summary 114 chapters pregrobbing phenomena in the cyanidation of gold ores 116 objectives of this chapter 116 background information 116 pregrobbing behaviour by the ores at low cyanide
Request PDF | Pregrobbing phenomena in the cyanidation of sulphide gold ores | The ability of pyrite and chalcopyrite to adsorb gold was examined. Experiments were conducted in cyanide
Pregrobbing phenomena in the cyanidation of sulphide gold Free download as PDF File (.pdf), Text File (.txt) or read online for free.
1/11/2000#0183;#32;Pregrobbing phenomena in the cyanidation of sulphide gold ores 1. Introduction. Pregrobbing is the phenomenon whereby the gold cyanide complex, Au (CN) 2, is removed from solution... 2. Experimental methods. A flotation feed, pyrite concentrate and a
ore were evaluated based on the adsorption of gold by ore from the spiked solutions (05 mg/L Au). A free milling gold ore and a synthetic pregrobbing gold ore, which was prepared by adding activated carbon to the free milling gold ore, were also tested to confirm the validity of the method adopted.
The investigation results show that the presence of artificial carbonaceous materials at 2% (w/w) in the gold ore significantly reduces gold recovery. Pretreatment of artificial pregrobbing ore prior to cyanidation by mixing with kerosene, diesel oil and pine oil for improved gold
The treatment of a copper sulphidebearing gold ore by direct cyanide leaching, ammonia pretreatment and ammoniacal cyanide leaching was investigated. Pregrobbing is an important phenomenon
that gold cyanide is reduced on the surface of sulphide minerals (Adams et al., 1996). The pregrobbing phenomenon was examined for materials with a high concentration of chalcopyrite and pyrite (Rees and van Denventer, 2000). The concentration of free cyanide proved to be critical to avoid the pregrobbing of gold by sulphide minerals.
be recovered by wholeore cyanidation, or some combination of flotation and cyanidation. Acceptable extraction of refractory gold can only be achieved by employing a preoxidation process prior to cyanide leaching. Antimony, bismuth sulfide and telluride gold ores: Antimony, bismuth sulfide and telluride gold ores are often somewhat
Chemical Interference This occurs when there are minerals in the ore that consume large quantities of cyanide or oxygen. Pregrobbing When the ore contains graphite or other carbonaceous matter; the gold, which often leaches well into solution, is pulled out
1/10/2005#0183;#32;For sulphide ores (Rees and van Deventer, 2000) suggested that pregrobbing was cyanide concentration dependent. In the presence of free cyanide it was shown that pregrobbing was unlikely to occur and any that did occur was easily reversed by the addition of activated carbon.
Keywords: Gold, Cyanide, Leaching, Bottle Roll Test, Pregrobbing, Cyanicide 1. Introduction Cyanide leaching of gold is a very common methodology for evaluation of low grade gold ores. Despite risks associated with cyanide, the method proved to be highly effective provided that necessary precautions are taken. Gold cyanidation in field scale
This phenomenon occurs in cyanidedeficient solutions and the extent of pregrobbing is related to the cyanide consuming ability of the ore, rather than simply the ore''s mineralogy. Activated carbon was found to compete strongly with the ore for aurocyanide in solution, although when no cyanide was present the kinetics of the two processes
Gold bearing ores that include basemetal mineralization, particularly copper, are classified as complex ores. These ores will often consume cyanide and create issues in CIP and elution. Pregrobbing carbon is defined as the phenomenon whereby the gold cyanide complex is removed from solution by constituents of the ore (Rees amp; van Deventer, 2000).
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