Solvent Extraction of Gold(I) Directly from Alkaline Cyanide Solution with Dibutyl Sulfoxide and n-Octanol

Abstract

The direct extraction of gold from alkaline cyanide solution with dibutyl sulfoxide and n-octanol diluted in kerosene was investigated. It has been indicated that the gold extraction percentage increases by increasing dibutyl sulfoxide concentration, n-octanol concentration, and organic-to-aqueous (O/A) phase ratio, but decreases with the increase of initial gold concentration and equilibrium pH of the aqueous phase. No gold extraction was observed using n-octanol alone as an extractant, but n-octanol had an obvious synergistic effect on gold extraction with dibutyl sulfoxide. The extraction reaction was rapid for the extraction equilibrium and could be established within 3 minutes. Gold loaded in the organic phase could be stripped effectively by Na 2 S 2 O 3 solution. It was indicated that at Na 2 S 2 O 3 concentration 0.12 molAEL À3 , aqueous-to-organic (A/O) phase ratio 1.0, and retention time of 5 minutes, the gold stripping percentage reached 92.6 pct.

Mechanism and Kinetic Model for Autocatalysis in Liquid–Liquid System: Oxidation of Dibutyl Sulfide with Aqueous Hydrogen Peroxide

“…In this paper, the oxidation of dibutyl sulfide (DBS) to dibutyl sulfoxide (DBSO) was selected as the model system. DBSO was valuable organic solvent widely applied in extraction of zirconium, palladium, platinum, and gold. − The aim of the research was to explore the autocatalytic phenomenon in the liquid–liquid system and establish reasonable mechanisms and kinetic models. The effects of temperature, stirring speed, equilibrium of aqueous H 2 O 2 in two phases, initial aqueous H 2 O 2 concentration, and initial organic DBSO concentration were investigated.…”