Many precious metal ores contain copper minerals in various amounts. These copper minerals dissolve in cyanide solutions to a greater or lesser degree depending on the particular copper mineral or minerals present, their fineness, and the dissolving effect of the cyanide solutions. In the process of dissolution the copper combines with, or as it is termed, consumes cyanide and, if the amount ...
cyanide copper leaching is a competitive alternative. The feasibility of using alkaline cyanide solutions for leaching copper, gold, and silver from ores has been well known at laboratory scale.
Many common copper minerals are soluble in the di- lute cyanide solution, typical of leach conditions found in the gold cyanidation process. Minerals such as azurite and malaquite, are fast leached and soluble in dilute cya- nide solutions.
In the cyanidation of different copper–gold ores, in order to improve the dissolution of gold and decrease the cyanide consumption, glycine can be added to the copper–cyanide solutions, either in the leaching stage after the copper–cyanide species have been formed, or into the final barren solutions containing copper–cyanide species after the gold has been loaded onto the activated carbon.
In the dissolution of copper minerals where the copper is in the 2 oxidation state, it is well known that cyanide is oxidised as a result of the reductive copper leach process to form soluble copper I cyanide see next section . However, there is little data available on the oxidation of cyanide in the presence of dissolved copper I .
In the cyanidation of copper–gold ores, the presence of copper minerals can lead to soluble gold losses, the production of weak acid dissociable WAD cyanide, as well as a number of operational challenges in CIP/CIL circuits with regard to competitive adsorption, and subsequent difficulties associated with elution, electrowinning and smelting.
in cyanide while more refractory copper sulphides such as chalcopyrite, cubanite, and enargite leach considerably slower in cyanide Adams, 2000 . As a result of cyanide soluble copper in the ore, cyanidation of gold‐copper ores results in high cyanide consumptions and difficulty in process control. The gold leaching reaction in cyanide ...
During cyanide leaching of gold ores, most copper minerals present in the ore readily dissolves by forming copper I -cyanide complexes, which results in excessive cyanide consumption coupled with ...
The effect of glycine addition on gold leaching kinetics in copper–cyanide solutions under different leaching conditions was studied. The results show that, in the presence of glycine, gold dissolution rate increases significantly in solutions containing copper–cyanide species at a very low, or zero, free cyanide concentration. In the presence and absence of glycine, gold dissolution rates ...
2020-8-13 · Selective leaching Glycine The presence of copper minerals with gold is known to lead to many challenges during the cyanidation of gold ores, such as high consumption of cyanide with low gold extraction and undesirable impacts on gold recovery during the downstream processes.
Process. 50 1997 127-141 Table 4 Effect of cyanide concentration on gold leaching of a copper-gold ore Test NaCN NaCN cons. Cu Fe Au rec. mg/L kg/t rag/L mg/L % 10 500 1.56 675 4 89.4- 12 640 1.76 691 6 96.5 4 710 1.85 713 8 96.8 11 840 2.78 770 24 96.6 Pre-leaching: Pb NO3 2 200 g/t, 30 rain; cyanidation: pH 10.5, 02 15 ppm, 48 h. The additional free cyanide does not promote ...
Leachable copper is the true head grade for heap leaching, and the orebody should be modelled accordingly. Select the appropriate leachable copper assay procedure. Better to start correctly than ...
Table of ContentsBringing Copper Metal into SolutionRecovering Copper Metal from Leach LiquorsCopper Leaching EquipmentCopper Leaching CostsCopper Leaching Practices The advance made in recent times in this branch of metallurgy is indi ed by the attention the subject is receiving from important American Copper producing companies. Reference to the files of publi ions devoted to the mining ...
leach significant quantities of gold without consuming excessive quantities of reagents. Thiosulphate is a more effective lixiviant of preg-robbing and high-copper ores than cyanide because ammoniacal thiosulphate leaching is less sensitive than cyanidation to contamination by unwanted ions.
in cyanide while more refractory copper sulphides such as chalcopyrite, cubanite, and enargite leach considerably slower in cyanide Adams, 2000 . As a result of cyanide soluble copper in the ore, cyanidation of gold‐copper ores results in high cyanide consumptions and difficulty in process control. The gold leaching reaction in cyanide ...
During cyanide leaching of gold ores, most copper minerals present in the ore readily dissolves by forming copper I -cyanide complexes, which results in excessive cyanide consumption coupled with ...
2020-8-13 · Selective leaching Glycine The presence of copper minerals with gold is known to lead to many challenges during the cyanidation of gold ores, such as high consumption of cyanide with low gold extraction and undesirable impacts on gold recovery during the downstream processes.
The leaching of gold in the presence of soluble copper does not proceed quickly until the ratio of CN:Cu is above 3. Below this ratio the equilibrium position of copper-cyanide complexes lies strongly away from the free cyanide ion, and gold leaching must proceed through a mechanism using the Cu CN 3 2-as a lixiviant Breuer et al., 2005 .
Copper extraction from primary copper sulfide ore from a typical porphyry copper deposit from Antofagasta, Chile, was investigated after leaching with a chloride-ferrous media at two temperatures. The study focused on whether this chemical leaching system could be applied at an industrial scale. Leaching tests were conducted in columns loaded with approximately 50 kg of agglomerated ore; the ...
Liberation: Cyanide leaching will only be effective if the cyanide can come in contact with the gold particle. For this to happen, the ore should either be sufficiently porous for cyanide to reach the gold, or more usually the ore is crushed and ground to a size at which the surface of the gold is exposed – i.e. the gold is liberated.
Heap leaching is a metal extraction process from low grade ores where crushed ore is stacked on an impermeable pad and irrigated from the top with a solution of chemical reagents. An enriched solution containing the targeted metal is collected at the bottom. This technique involves complex chemical/electrochemical reactions and transport processes. Among the main features of this method of ...
It includes the stages such as leaching pulp preparation, leaching and adsorbing, gold removal carbon recycling, pulp agitation, and gold loaded carbon desorption. Appli ion : It suits for large gold mines with high grade gold and gold deposits associated with higher concentrations of silver and copper.
During cyanide leaching of gold ores, most copper minerals present in the ore readily dissolves by forming copper I -cyanide complexes, which results in excessive cyanide consumption coupled with ...
Leaching is followed by a neutralization step and then copper solvent extraction and electrowinning. Gold and silver can be recovered by adding a lime boil step before cyanide leaching. The Copper Pressure Oxidation Plant is an Outotec proprietary technology for impure concentrate refining. The new process offers an effective way to dissolve ...
Copper I cyanide is an inorganic compound with the formula CuCN. This off-white solid occurs in two polymorphs ; impure samples can be green due to the presence of Cu II impurities. The compound is useful as a alyst , in electroplating copper, and as a reagent in the preparation of nitriles .
Copper and cyanide recovery from barren leach solution at . leach considerably slower in cyanide Adams 2000 . As a result of cyanide soluble copper in the ore cyanidation of gold‐copper ores results in high cyanide consumptions and difficulty in process control. The gold leaching reaction in cyanide solution follows these electrochemical ...
Copper-containing minerals are problematic, because it forms stable copper-cyanide complexes upon leaching with cyanide. The dissolution of copper consumes a substantial uantity of cyanide, thereby increasing reagent costs. In addition, any copper-cyanide in the pregnant leach
Heap leaching is a metal extraction process from low grade ores where crushed ore is stacked on an impermeable pad and irrigated from the top with a solution of chemical reagents. An enriched solution containing the targeted metal is collected at the bottom. This technique involves complex chemical/electrochemical reactions and transport processes. Among the main features of this method of ...
The method is akin to the cyanide technique, above, except sulfuric acid is utilized to dissolve copper from its ores. The acid is recycled from the solvent withdrawal circuit and is used again on the leach pad. A byproduct is iron II sulfate, jarosite, which is manufactured as a byproduct of leaching pyrite, and at times even the same sulfuric acid that is needed for the procedure.
It includes the stages such as leaching pulp preparation, leaching and adsorbing, gold removal carbon recycling, pulp agitation, and gold loaded carbon desorption. Appli ion : It suits for large gold mines with high grade gold and gold deposits associated with higher concentrations of silver and copper.
soluble copper–cyanide complexes such as Cu CN 2 −, Cu CN 3 2− and Cu CN 4 3−. The distribution of these complexes in the leach solution is normally a function of the cyanide concentration and pH Dai et al., 2005 . Recently, the recovery and re-use of the copper–cyanide com-plexes from the final leaching solution streams have ...
Ore processing is by conventional cyanide heap leaching, which produces a pregnant leach solution PIS containing 1-2 ppm of gold, together with 1000 ppm or more of copper. The PIS is treated by ...
copper cyanide ore hcn recovery Prior art date 1964-12-14 Legal status The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed. Expired - Lifetime Appli ion number US418324A Inventor Lower George William
For proper heap design for cyanide leaching of copper-bearing gold ores, it is necessary to run long-term column tests typically 60 to 180 days at two or three different cyanide and/or pH levels. The relationships between gold-silver-copper recoveries, cyanide levels, and leach times will be different for each orebody. Since gold-copper types of
Copper I cyanide is an inorganic compound with the formula CuCN. This off-white solid occurs in two polymorphs ; impure samples can be green due to the presence of Cu II impurities. The compound is useful as a alyst , in electroplating copper, and as a reagent in the preparation of nitriles .
Many non-cyanide copper processes operate between 54–65 C 130–150 F with air agitation. A typical bath formulation contains 11g/L of copper metal. The pH is around 9.0, while cyanide copper solutions have a pH of at least 11.0. The anode-to- hode ratio is 2:1, with the same anodes used in cyanide copper solutions.
Gold Leaching with Elevated Copper GlyCatTM GLYCATTM INTRODUCTION Small amounts of cyanide used in conjunction with a glycine-dominant lixiviant has many beneficial properties, particularly for the leaching of precious metals with elevated copper content. This is a consequence of copper preferentially bonding to
4.3 CYANIDE LEACHING OF THE COPPER CONCENTRATE 92 4.3.1 The effect of copper 101 4.3.2 The role of iron 106 4.3.3 The role or nickel 107 4.3 .4 The role of silver 109 4.3.5 Theroleofzinc 109 4.4 THE EFFECT OF COPPER CYANIDE ON GOLD LEACHING FROM OXIDE AND SULPHIDE ORES 110 4.5 SUMMARY 114 CHAPTERS PREG-ROBBING PHENOMENA IN THE