Investigation on the Extraction Mechanism of Au (I) from Cyanide Solution with Quaternary Ammonium System

The mechanism of Au (I) extraction has been characterized using 198Au radiometry, thermodynamic equilibrium, Karl-Fischer titration and FT-IR spectroscopy techniques. The results indicate that the extraction follows ionic combination and solvent interaction mechanism. The stoichiometry of the extracted species is 1:1:4:4 for TDMBA+: Au(CN)2- : TBP : H2O. The microstructure model of the extracted complex is a supramolecular structure via hydrogen bonding, ion dipole interaction and ionic combination. The extraction process can be described as micelles in the aqueous phase transfer into the organic phase and reversed micelles or microemulsion (W/O) form in the organic phase.