Gold solvent extraction from typical cyanide leach solutions

Integrated membrane process for gold recovery from hydrometallurgical solutions

“…The authors have used as high a LIX79 concentration as 30% for the effective recovery of gold in the presence of several other metal cyanides. Based on the preceding results, the following order of selectivity with 18% LIX79 was obtained at pH 10.6 while maintaining NaCN 5000 in the feed (Table 6) These results agree with previous works, which indicates that LIX79 has a higher affinity for univalent ions, such as Au(CN),-, than for multivalent ions, such as Cu(CN);-, Fe(CN);-, Cu(CN)?- (Virnig and Wolfe, 1996;Kordosky, 1992). Also, the extraction of these complexes strongly depends on the metal coordination number; from the results shown in Table 6, it is seen that the extraction order follows the series Me(CN),-> Me(CN),"-> Me(CN),"-.…”

“…Based on the previous studies, LIX79 containing a guanidine functionality (Henkel Co.) was chosen as an extractant that has a good extractability at pH > 9 and stripping of Au(1) in highly basic (pH > 12) solutions Kordosky et al, 1992;Virning and Wolfe, 1996).…”

“…The stripping process seems to be complicated on an industrial scale, because (1) acidic thiourea was suggested as a stripping agent, and (2) incineration of gold-loaded quaternary amine salt was advised in order to obtain pure gold metal. Kordosky et al (1992) have developed a solvent extraction (SX) process for gold(1) recovery using an SX circuits with reagent N-N-bis (2 ethylhexyl) guanidine and N-N'-bis (tridecyl) guanidine (similar to LIX79 containing guanidine functionality). In spite of good performance, third phase and crud formation were reported by the authors.…”

Continuous Laboratory Gold Solvent Extraction from Cyanide Solutions using LIX 79 Reagent

“…However, precious metals solvent extraction is a technology not fully developed due to several factors, such as the lack, until recently, of a solvent capable of: (1) extracting the precious metals from typical cyanide solutions, and (2) stripping the precious metals into a solution from which they can be electrowon. In the last decade, nonetheless, several investigators have been evaluating guanidine-based extractants which meet the above specifications (Kordosky et al [3], Miller and García [4], Viring and Mackenize [5], Viring et al [6], Kordosky et al [7], and Valenzuela et al [8]). Kordosky et al [3] showed that reagents with the guanidine ion pairing functionality exhibited strong affinity and selectivity for gold from typical low-grade cyanide leach liquors.…”

“…In the last decade, nonetheless, several investigators have been evaluating guanidine-based extractants which meet the above specifications (Kordosky et al [3], Miller and García [4], Viring and Mackenize [5], Viring et al [6], Kordosky et al [7], and Valenzuela et al [8]). Kordosky et al [3] showed that reagents with the guanidine ion pairing functionality exhibited strong affinity and selectivity for gold from typical low-grade cyanide leach liquors. Stripping was easily accomplished at a pH ≥ 13.5.…”