Discussion of the kinetics of copper solvent extraction with hydroxy oximes

Abstract

Interpretation of copper solvent extraction data recently published in this journal by Flett et al.[3] is discussed. The rate data for copper solvent extraction with hydroxy oximes (LIX reagents) was obtained by a relaxation technique using radioactive copper tracer and the AKUFVE apparatus. The technique suggests, and it is shown in the following discussion the data substantiate, that the back reaction kinetics contribute significantly to the net reaction rate. The correct empirical expression for the rate of disappearance of copper from the aqueous phase is shown to be: − Rate = k f( R 65 H) org ( R 63 H) 1 2 org ( Cu 2+) aq − k r( R 2 65 Cu) org ( H −) aq . Other consideration is given to the meaning of the activation energies obtained and evaluation of the proposed reaction mechanism.