Liquid-liquid extraction and separation of copper(II) and nickel(II) using LIX®984N
NB Devi, B Nayak
The extraction of copper(II) from sulphate solution was investigated using
LIX®984N in kerosene. The parameters that could affect the extraction,
such as equilibrium pH, extractant concentration, salt concentration,
various diluents, and temperature, were separately investigated. On the
basis of slope analysis, the complex formed in the organic phase is
proposed to be CuR2, where R is the anionic part of LIX®984N. The
extraction equilibrium constant and Gibbs free energy (?G) of the
extraction process were determined. The positive value of ?H obtained
from temperature variation studies showed that the extraction process is
endothermic. The extraction of copper was lowest when chloroform was
used as the diluent. Separation and recovery of copper from a synthetic
copper-nickel solution containing 6.35 g/L Cu(II) and 0.58 g/L Ni(II) was
carried out using 20%(v/v) LIX® 984N. The separation factor (ß = DCu/DNi)
was found to be pH-dependent. A two-stage batch countercurrent
extraction was carried out at an O:A ratio of 3:4 at equilibrium pH 1.05 for
extraction of copper from copper-nickel solution, followed by copper
stripping from the loaded organic phase with 15% H2SO4 at an O:A ratio
of 3:1.
Keywords: copper, nickel, LIX® 984N, solvent extraction, stripping.