Liquid–liquid extraction of nickel at macro-level concentration from sulphate/chloride solutions using phosphoric acid based extractants

Extraction of nickel was studied at macro-level concentrations (∼0.5 M) from solutions containing sodium sulphate/chloride using the extractants D2EHPA, PC 88A and Cyanex 272. Increase of sodium salt concentration in the feed solution (0–1.0 M) resulted in decrease in nickel extraction. This influence is more prominent with the extractant D2EHPA. At a given nickel: sodium salt ratio, variation in nickel/sodium salt concentration influenced the extraction. Temperature (in the range of 30–45 °C) and contact time (beyond one minute) had no effect on extraction. The loading capacity of 1.0 M D2EHPA, PC88A and Cyanex 272 (70% neutralised) was observed to be 17.7, 18.2, and 18.7 kg/m3 in the sulphate system and 20.74, 20.75, and 20.35 kg/m3 in the chloride system. The extracted species appears to be NiR2.