An alkaline glycine-based process for copper recovery and iron rejection from chalcopyrite
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© 2016 TAPPI Press. All rights reserved. A process has been developed at Curtin University whereby glycine is used in an alkaline environment to leach gold, silver and copper from their ores, concentrates, process intermediates and wastes. Copper mineralisation investigated includes various oxides, sulfides and native copper. The leach process utilises an oxidising environment such as oxygen. Glycine is a non-toxic, non-volatile, edible, low cost reagent which is produced in large industrial quantities for use in several industries. Glycine and its copper and precious metals complexes are stable over wide pH, Eh and temperature ranges. Other than losses in leach residues, the glycine is recovered and recycled for leaching. Iron dissolution is insignificant in the pregnant leach solution. Iron in pyrite remains unaffected, whereas iron associated with base metal sulfides (e.g. chalcopyrite and bornite) is converted to a readily filterable iron hydroxide. Efficient separation of copper by solvent extraction and conventional electrowinning has been shown to be feasible for a number of organic extractants, whereas gold and silver glycinates adsorb very well onto carbon allowing CIP/CIL/CIC (carbon-in-column) based processes. The process is ideal for ores containing acid-consuming gangue, concentrates with high arsenic or halide contents and for copper-gold ores with significant sulfide mineralisation. The process eliminates many of the problems associated with the processing of copper-gold-silver ores, such as elemental sulfur formation, silica gels, unwanted metal co-dissolution, and jarosite precipitation. The reagents used and process residues are much safer and environmentally benign than conventional process options. The processing technology can be applied to in-situ, heap and vat, or agitated tank leaching at temperatures ranging from ambient to below 100C at atmospheric pressure and is currently being commercialised. This paper will focus on copper leaching and recovery and iron rejection from a chalcopyrite flotation concentrate.
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Gold and copper leaching from gold-copper ores and concentrates using a synergistic lixiviant mixture of glycine and cyanideOraby, E.; Eksteen, Jacques; Tanda, B. (2017)© 2017 Elsevier B.V.The presence of cyanide soluble copper in the cyanidation of gold-copper ores and concentrates significantly increases the cyanide consumption in order to achieve sufficient gold recovery. In addition, ...
Oraby, E; Eksteen, Jacques (2014)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 ...
Eksteen, Jacques; Oraby, E.; Tanda, B. (2017)A conceptual flowsheet is proposed and the main processing steps are evaluated for the alkaline processing of chalcopyrite where glycine is the complexing agent. Glycine is utilised in an oxidising, alkaline environment ...