Innovative synergistic extraction of copper(II) from sulfate solutions using D2EHPA and Tri-n-octylphosphine oxide

Solvent extraction is a critical process in the copper extraction industry, offering an advanced method for separating and purifying copper from its ores. As industries aim for increased efficiency and sustainability, the significance of enhancing copper extraction methods is increasingly evident. The liquid-liquid extraction of copper(II) from sulphate medium with di(2-ethylhexy1) phosphoric acid (D2EHPA, HL) has been investigated in chloroform and 1-octanol at 25°C. The study examined the impact on several factors, including the equilibrium pH, extractant concentration, and the nature of diluent. The extracted copper(II) species were found to be CuL2.2HL in chloroform and CuL2 in 1-octanol and the extraction constants of these species were also estimated. The effect of the presence of tri-n-octyl phosphine oxide (TOPO) on the above extraction systems was also studied. A strong antagonistic effect observed during the extraction of copper(II), in the chloroform system is caused by a D2EHPA–TOPO interaction. In the 1-octanol system, the presence of TOPO may change the reaction stoichiometry of copper(II) and D2EHPA.