Solvent Extraction of Gold from Alkaline Cyanide Solution with a Tri‐n‐octylamine/Tri‐n‐butyl phosphate/n‐heptane Synergistic System

Abstract

Solvent extraction of KAu(CN) 2 from alkaline cyanide solution by using the pre-acidified tertiary amine, tri-n-octylamine(TOA) as extractant with the addition of trin-butyl phosphate (TBP) as a synergist has been studied. The influence of several variables such as the molar ratio of TOA to KAu(CN) 2 (n r ), the volume percentage of TBP (w TBP ), the phase ratio of the organic phase to the aqueous phase and the pH value of the aqueous phase were investigated. The results indicated that, at a certain pH range, while w TBP is above 20%(v/v) and n r is bigger than 1, the organic phase can extract gold from the aqueous phase completely. The relationship between the extraction percentage of gold (E) against n r and the logD 2 logw TBP plot indicate that the stoichiometry of the extracted species is a 1 : 1 : 3 complex, namely, [TOA . H þ ] . [Au(CN) 2 2 ] . 3TBP. Dynamic laser scattering (DLS) method reveals that the organic phase tends to self-assemble to form aggregations when the concentration of gold in the organic phase reaches a certain limiting value. The stripping of the loading organic phase by NaOH and inorganic salts, such as NH 4 SCN, NaClO 4 and potassium halides, has also been investigated.

Separation and enrichment of gold(III) from environmental samples prior to its flame atomic absorption spectrometric determination

“…Hence, separation and enrichment of analyte are important aspects in determination of gold in addition to the effect of other trace metal ions in saline matrices [6][7][8][9]. For this purpose, several separation and enrichment techniques for gold (and for trace metal ions) including solvent extraction [10][11][12], co-precipitation [13][14][15], sorption, [16][17][18][19][20] etc., have been developed. One of this technique, solid-phase extraction (SPE) by Amberlite resins has been widely used for separation and enrichment of almost all the other trace metals, besides gold [21][22][23][24][25][26][27][28][29].…”

Solvent extraction of chromium(VI) from hydrochloric acid solution with trialkylamine/kerosene

“…It is noteworthy that solvent extraction is one of the most effective techniques for the recovery of chromium which is widely used in separation science [3]. With this technique, the amine extractants such as tertiary amines (Alamine 336 and trioctylamine [TOA]) and quaternary ammonium salts (Aliquat 336) have attracted great interest from researchers due to their superiority to selectively extract metal ions such as Zn [4], Cr(III) [5], Pd [6] noble metals [7], and rare earth metals [8]. In addition, a number of researches related to the solvent extraction of chromium(VI) with amine extractant are available in the literature [9][10][11][12][13][14][15].…”

Ion-pairbased liquid–liquid extraction of gold(III) from malonate media using 2-octylaminopyridine as an extractant: analysis of alloys, minerals, and drug samples

“…8−14 Solvent extraction is an impressive and effective technique for recovery and separation of gold using various extractants. Some of the extractants reported for gold(III) are N-n-octylaniline, 15 Cynex 923, 16,17 tributylphosphate, 18 phospholene, 19 tri-n-octylamine, 20 tri-n-butyl phosphate, 21 Alamine, 22 LIX 79, 23 cyphos IL 101, 24,25 quarternary amine, 26 Cyanex 302, 27 Cyphos IL 109, 28 N-n-decylaminopyridine, 29 and Alamine 336 30 . Separation and enrichment of trace levels of gold in environmental samples was conducted with Amberlite XAD-2000 31 and sorbent extraction for preconcentration of gold on an activated carbon column.…”