Selective Solvation Extraction of Gold from Alkaline Cyanide Solution by Alkyl Phosphorus Esters

Abstract

Research efforts have shown that solvation extraction of gold from alkaline cyanide solution is possible by alkyl phosphorus esters. Both tributyl phosphate (TBP) and dibutyl butyl phosphonate (DBBP) appear to be effective extractants for gold and exhibit high loading capacities exceeding 30 gpl. Selective solvation extraction of—gold from alkaline cyanide solution can be achieved with selectivity factors relative to other cya-noanions as high as 1000 under certain circumstances. Variables influencing the selectivity such as ionic strength, temperature, and extractant structure, are discussed in terms of the extraction chemistry, which seems to involve the solvation of a ion pair.