KINETICS OF MILLERITE DISSOLUTION IN CUPRIC CHLORIDE SOLUTIONS

Oxidation of millerite by cupric chloride in sodium chloride solutions has been studied as a function of: rate of agitation; leaching time; temperature; acid concentration; and total initial cupric concentration. The reaction has a 0.5 order of dependence on initial cupric concentration in the range 0.0-0.5 M. The activation energy for the temperature range 333-363 K was found to be 65.2 kJ/mol with chemical reaction at the mineral surface as the rate-controlling step. The rate expression, for initial cupric concentrations between 0.0 and 0.5 M, is: {1-(1-alpha)(1/3)} = {9.27 X 10(3) . [Cu(II)](0.5). r(0)(-1)exp(-7.847 X 10(3)/T)} . t according to the shrinking-core model.