Solvent Extraction of Gold(I) from Alkaline Cyanide Solution with Synthesized Sulfoxide MSO under Assistance of TBP

In this work the extraction performances of gold(I) from alkaline solution using a synthesized sulfoxide MSO with assistance of TBP and n-octanol were investigated in details. Several extraction parameters were studied. The results indicated that effective extraction of gold could be realized with increasing MSO concentration at a constant TBP concentration and a fixed phase ratio. TBP exhibited poor extraction for gold without MSO from alkaline cyanide solution, but it could facilitate MSO to transfer gold(I) even with a lower concentration of MSO. N-octanol had no extracting ability for gold(I), but effectively assisted MSO to extract gold(1). Using an organic phase containing 0.7 mol.L-1 of MSO, 30% (v/v) TBP and 20% (v/v) n-octanol, the percentage extraction of gold reached 98.6%, and the fast extraction reaction equilibrium could be established within 2 min. The stripping behaviors of gold-laden organic phase were carried out using sodium thiosulfate (Na2S2O3) solution. The percentage stripping of gold reached 92.6% when Na2S2O3 concentration was 30 g.L-1. Gold(I) could be extracted directly from alkaline cyanide solution efficiently using an organic phase composed of MSO, TBP and n-octanol, and efficiently stripped by Na2S2O3 aqueous solution. Further study may fulfill its potential application in the extraction and separation of gold.