Modeling of the Extraction Equilibrium of Copper from Sulfate Solutions with Acorga M5640

Abstract

The extraction equilibrium of copper from sulfate media with the aldoxime Acorga M5640 in ShellSol D70 has been investigated. The distribution results were interpreted by taking into account the nonideality of the aqueous phase. The activity of copper and hydrogen ions in the target systems CuSO₄/H₂SO₄/Na₂SO₄ and CuSO₄/H₂SO₄/Fe₂(SO₄)₃/ZnSO₄ were calculated through the speciation of the aqueous solutions and by applying the Pitzer model. The experimental pH values were found in good agreement with the predicted pH values. A model considering the dimerization of the aldoxime extractant was proposed to predict the distribution ratio and the copper loading isotherms. The extraction constant at infinite dilution and the apparent dimerization constant were evaluated from the experimental data and were found to be 10^{3.06 ± 0.07} and 51 ± 9 M⁻¹, respectively, at 25°C.

Keywords:

• Speciation
• ions activity
• copper extraction
• Acorga M5640
• extraction constant

ACKNOWLEDGMENTS

Financial support of “Fundação para a Ciência e a Tecnologia” (FCT, Portugal), the European Community, through the project FCT PDCT/EQU/61733/04, and “Agência de Inovação” (Adi, PRIME-IDEIA, Portugal) through the project PROJECTO ZINCO 70/00191 is gratefully acknowledged. The authors would like to thank Drogas Vigo (Portugal) for supplying the diluent ShellSol D70. Shiva Agarwal also acknowledges the postdoctoral fellowship (SFRH/BPD/32429/2006) from the FCT. The authors gratefully acknowledge Professor Matilde Marques (Centre of Structural Chemistry, Instituto Superior Técnico, Technical University of Lisbon) for her helpful discussion concerning the possibility of using NMR to interpret the data.