Patent ID: 8911533
Filing Date: 2014-12-16
Classification: C22B,Y02P

Abstract:
1. A method of recovering gold from an aqueous solution having a gold concentration of 10 mg/L or lower, employing a plurality of extraction apparatuses for bringing the aqueous solution into contact with an extraction solvent arranged to configure a multi-stage extraction process, wherein the method allows the aqueous solution continuously flows from a first-stage extraction to a second-stage extraction, while recycling the extraction solvent used in each stage twice or more times within the same stage, without back extraction and reduction; wherein in the first-stage extraction, the volume ratio (O/A) of the extraction solvent (Or) and the aqueous solution (Aq) is ⅕ or smaller, and the used extraction solvent is repeatedly used until the concentration of gold in the extraction solvent is 1 g/L or higher; wherein in the second-stage extraction gold is repeatedly extracted until the concentration of gold in a post extraction liquid reaches to 0.5 mg/L or below; and wherein the extraction solvent present in the first-stage is separately prepared and recycled principally within the first-stage of extraction and the extraction solvent present in the second-stage is separately prepared and recycled principally within the second-stage of extraction.