Extraction Equilibrium of Copper from Ammoniacal Media with LIX 54

Abstract This paper reports a study of the extraction of copper from ammonia/ammonium sulfate medium with LIX 54, a β‐diketone. The extraction of copper is very sensitive to the equilibrium pH. The highest extraction efficiency is attained in the range of pH 8–9.5. Above pH 10, the percentage of metal ion extracted decreases sharply. The extraction of copper by LIX 54 can be described by the following equation: The thermodynamic equilibrium constant was evaluated in terms of the aqueous phase and was found to be 10(2.89±0.03) M2 at 298 K. The nonideality of the aqueous phase was taken into account by applying the Pitzer model and the extended Debye‐Huckel equation. The isotherms of extraction for the system copper/ammonia/ammonium sulfate/LIX 54 revealed that the increase in the salt concentration from 0.2 to 1 M makes the extraction process difficult.