Kinetics of sulfur transfer from H₂S to digenite (Cu_2-xS) at 500°C

The kinetics of sulfur transfer from H₂S to cuprous sulfide (digenite) at 500°C has been established by the resistance relaxation technique. The resistance measurements have been carried out by the van der Pauw method, which uses a four probe configuration. The rate of the forward reaction decreases with the increase in the activity of sulfur in the sulfide (rate ∞a_s^-0.55) while the rate of the backward reaction is found to be nearly independent of the sulfur activity. Based on these results, the rate limiting step for sulfur transfer reaction to digenite is shown to be: H₂S (g) + 2e^- = S^2-(ad) + H₂(g).