The phosphine oxides Cyanex 921 and Cyanex 923 as carriers for facilitated transport of gold(I) cyanide aqueous solutions

The behaviour of the phosphine oxides Cyanex 921 and Cyanex 923 in the facilitated transport of gold(I) from cyanide solutions is described. Transport is studied as a function of several variables such as stirring speeds of the aqueous phases, membrane phase diluent, pH of the source phase, ionic strength, and gold and carrier concentrations. The separation of the gold(I) cyanide complex from other metal-cyano complexes present in the source phase as well as the behaviour of phosphine oxides with respect to other neutral organophosphorous derivatives (tri-n-butylphosphate (TBP) and dibutyl butylphosphonate (DBBP)) are also investigated.