Solvent extraction of gold(I) from alkaline cyanide solution by dibutylcarbitol (DBC) with n-octanol

BACKGROUND: Currently, cyanidisation is preferred for the extraction of gold because it has a number of advantages over other methods. Gold(I) can be extracted with various extractants, but there are no reports on the extraction of gold(I) from cyanide solution by dibutylcarbitol (DBC). In this work the extraction of gold(I) from alkaline cyanide solution using DBC with n-octanol was studied. Several factors affecting the percentage extraction of gold(I), including DBC concentration, diluent concentration, equilibrium time, phase ratio, pH and gold concentration in aqueous phase, were investigated. RESULTS: The results showed that 96.2%, of gold(I) could be extracted using an organic phase composed of 40% (v/v) DBC, 50% (v/v) n-octanol and 10% (v/v) odourless kerosene. The extraction was quite fast and equilibrium could be established within 2 min. Stripping of the gold-laden organic phase was carried out using sodium sulfite (Na2SO3) and sodium thiosulfate (Na2S2O3) Solutions, with Na2S2O3 proving better than Na2SO3. The percentage stripping of gold(I) was 96.5% when the Na2S2O3 concentration was 4% (w/w), and the stripping capacity of gold(I) exceeded 311.3 mg L-1 when the phase ratio (A/O) was equal to 0.2. CONCLUSION: Gold(I) can be extracted from aqueous cyanide solution by DBC in the presence of n-octanol and efficiently stripped by aqueous Na2S2O3 Solution. This method has the potential for practical application in the extraction and separation of gold. (c) 2008 Society of Chemical Industry.