Cuprous Sulfate Thermodynamics and Cuprous Perchlorate Oxidation Kinetics

摘要

Aqueous cuprous ion has uses as a reducing agent in hydrometallurgical applications. Cuprous ion may be formed by contacting an aqueous cupric salt with metallic copper. The equilibrium concentrations of cuprous ion in sulfate media and the oxidation rate of cuprous in perchlorate media were studied. The reduction of Se(VI), Se(IV), Te(VI) and Te(IV) ions with cuprous ion in acidic sulfate solutions was carried out at 95°C. A study of equilibrium cuprous concentrations for the cupric-copper metal reaction at different concentrations of cupric (25 to 110 g/L) and sulfuric acid (l0g/L, l00g/L and 200g/L) and at temperatures of 50 to 95°C was performed. Equilibrium cuprous concentration data were fitted to the relationship, [Cu~+] = Ve~(-w/r) [Cu~(+2)]~x(Y[H_2SO_4]~2+ Z[H_2SO_4] + 1) where [Cu~+], [Cu~(+2)] and [H_2SO_4] are in g/L at specified temperature T (K) and V to Z are empirical constants. Solution acidity had a very slight effect on cuprous concentration. The kinetics of the oxidation of cuprous by perchlorate in a perchloric acid solution at 95°C were also studied at sodium perchlorate concentrations of 0,1,2 and 3 molar, and Cu~(+2) and HClO_4 concentrations of 50 and 100 g/L respectively. The rate of cuprous oxidation was apparent first order with respect to cuprous concentration ([Cu~+] = [Cu~+_0]× e~(-kt)) with the rate constants varying from 1.75× 10~(-5) to 9.92× 10~(-5) sec~(-1) depending on the sodium perchlorate concentration.