SOLVENT-EXTRACTION OF IRON(III) BY MOC-55 TD - EXPERIMENTAL EQUILIBRIUM STUDY AND DEMONSTRATION OF LACK OF INFLUENCE ON COPPER(II) EXTRACTION FROM SULFATE-SOLUTIONS

Solvent extraction of iron(III) by means of the commercial aldoxime MO C-55 TD and its influence on copper(II) extraction from sulphuric solu tions has been studied. Extraction experiments were carried out varyin g the equilibration time, temperature, extractant concentration, aqueo us pH and the ferric and cupric ions concentrations. Iron(III) extract ion can be performed at pH values above 1, the extraction being endoth ermic (Delta H degrees = 52.5 kJ/mol). The extraction of the metal by MOC-55 TD can be represented by the equilibria: [GRAPHICS] where HR re presents the extractant molecule. It was also concluded that, under th e present experimental conditions, copper(II) is extracted preferably to iron(III) and the presence of this element does not appreciably inf luence the equilibrium constant of the copper extraction reaction by M OC-55 TD. (C) 1998 Elsevier Science B.V.