Efficient separation of copper and nickel from ammonium chloride solutions through the antagonistic effect of TRPO on Acorga M5640

• Acorga M5640 and TRPO were used to separate Cu(II) and Ni(II) in ammoniacal solution.
• TRPO led to efficient separation of Cu(II) and Ni(II) due to the antagonistic effect.
• A high copper-to-nickel separation factor of 35,250 was obtained.
• Quantitative extraction of Cu(II) was achieved from mixed solution with Cu(II) and Ni(II).

In this study, copper and nickel in ammoniacal/ammonium chloride solutions were separated by using an extractant mixture of Acorga M5640 and trialkylphosphine oxide (TRPO). The effects of contact time, Acorga M5640 concentration, modifier concentration, total ammonia concentration, and phase ratio on the extraction and separation of both metals were determined. The addition of TRPO into Acorga M5640 organic phase exerted antagonistic effects on copper and nickel extractions. The antagonistic effect of the extractant mixture was significantly stronger on the extraction of nickel than on that of copper. More than 99.96% of copper and less than 6.6% of nickel were extracted using a mixture of 10 vol.% Acorga M5640 and 2 vol.% TRPO in kerosene from an ammoniacal solution initially containing 3.0 g/L each of copper and nickel under optimal extraction conditions. The separation factor of copper over nickel reached 35,250.