DISSOLUTION KINETICS OF COPPER(II) OXIDE IN AMMONIUM-CHLORIDE SOLUTIONS

In the present work, the dissolution of copper (II) oxide in ammonium chloride solutions was studied. In the experiments, the following vari ables were chosen: the solution concentration, reaction temperature, s olid-to-liquid ratio, and stirring speed. It was observed that the dec rease in the solid-to-liquid ratio, and the increase of the reaction t emperature and solution concentration increased the dissolution rate. It was found that the stirring speed had no significant effect on the dissolution rate. The reaction kinetics of copper(II) oxide according to the heterogeneous and homogeneous reaction models were examined and it was found that the dissolution rate was controlled by diffusion fr om the product layer formed around the particle. The dissolution kinet ics can be expressed: 1-3(1-x)(2/3) + 2(1-X) = [5.39 . 10(6)(C)(2.41)( S/L)(-1.14)e(-9785/T)]. t The calculated activation energy was 81.3 kj mol(-1).