Extraction and separation of gold (I) cyanide in polyethylene glycol-basedaqueous biphasic systems

The extraction of gold (I) cyanide in polyethylene glycol-based aqueous bip hasic systems has been investigated. Almost all of gold (I) cyanide (> 96%) was transferred from salt-rich phase into the polyethylene glycol (PEG)-ri ch phase without addition of any extractant. No significant influence of so lution pH on gold (I) cyanide extraction was observed. The aqueous biphasic systems have high capability of extraction. The gold (I) cyanide in the PE G-rich phase can be easily reduced by addition of zinc. The PEG-rich phase could be reused for extraction of gold (I) cyanide without decrease of extr action capability. The PEG/salt aqueous biphasic systems may provide a pote ntial new technique for gold separation from cyanide solutions because all components of systems are virtually nontoxic and nonflammable. (C) 2001 Els evier Science B.V. All rights reserved.