Abstract: A method for separating gold and/or silver from copper or other contaminant metals is provided in which a suitable filter membrane (64), particularly a nanofilter, is used to form a retentate (134) containing most of the multivalent metal cyanide complexes and a permeate (135) containing most of the precious metal cyanide complexes. The process is particularly applicable to the recovery of gold and/or silver from ores containing these metals and one or more contaminant metals. The precious metal can thereafter be recovered from the permeate (135) and the metal in the multivalent metal cyanide complex from the retentate (134).

Abstract: A method for removing solid wastes from an organic extractant-based SX/EW copper processing system. A lixivant is initially applied to copper ore, followed by mixing of the copper-containing lixivant product with an organic extractant. The organic extractant (which contains extracted copper ions) is then contacted with an electrolyte solution. At least part of the remaining organic fraction after electrolyte contact is passed through a filtration membrane (either an ultrafiltration or microfiltration membrane) to remove solid wastes. The filtered organic fraction is then reused within the system, followed by electrowinning of the copper-containing electrolyte to recover purified copper. Alternatively, the organic extractant may be membrane-filtered after initial contact with the copper-containing lixivant product to remove solid wastes from the organic extractant.

Abstract: The present invention is directed to a process for removing various contaminants (e.g., organic collectors, contaminant metals or spectator ions, and/or suspended and colloidal solids) from process streams in leaching processes. The contaminant removal is performed by one or more membrane filtration systems (e.g., nanofilters, ultrafilters, and/or microfilters) treating process streams including, the pregnant leaching solution, the barren raffinate, and the lean and rich electrolytes.

Abstract: A method for separating gold from copper in a gold ore processing system. Gold ore containing elemental gold and elemental copper is treated with an aqueous cyanide solution to produce a liquid product containing a gold-cyanide complex and a copper-cyanide complex. The liquid product is then delivered to a nanofiltration membrane which prevents the copper-cyanide complex from passing therethrough while allowing passage of the gold-cyanide complex. Nanofiltration of the liquid product specifically produces (1) a retentate which contains the copper-cyanide complex; and (2) a permeate which contains the gold-cyanide complex. In this manner, the gold-cyanide complex is effectively separated from the copper-cyanide complex. The permeate is then treated (e.g. with activated carbon or elemental zinc) to ultimately obtain elemental gold therefrom. The copper-cyanide complex may either be discarded or treated to recover elemental copper from the complex.

Abstract: A method for removing solid wastes from an organic extractant-based SX/EW copper processing system. A lixivant is initially applied to copper ore, followed by mixing of the copper-containing lixivant product with an organic extractant. The organic extractant (which contains extracted copper ions) is then contacted with an electrolyte solution. At least part of the remaining organic fraction after electrolyte contact is passed through a filtration membrane (either an ultrafiltration or microfiltration membrane) to remove solid wastes. The filtered organic fraction is then reused within the system, followed by electrowinning of the copper-containing electrolyte to recover purified copper. Alternatively, the organic extractant may be membrane-filtered after initial contact with the copper-containing lixivant product to remove solid wastes from the organic extractant.