Reactions of molten Fe,Co, Cu,and Pb sulfides with hydrogen

The kinetics and mechanism of reactions of molten Fe, Co, Cu, and Pb sulfides with hydrogen have been investigated between 1080° and 1340°C. While maintaining high flow rates of hydrogen and argon to ensure chemical control, the rate of reduction of these sulfides was found to be second order in sulfur concentration and half-order in hydrogen pressure. These dependences are similar to those reported earlier for molten nickel sulfide reduction by hydrogen. The kinetics and mechanistic proposal suggest a metal catalyzed step. If the activation energies for the rate determining step of S₂ reacting with hydrogen in the melt for the various sulfides are compared with the values for the hydrogen-liquid sulfur or hydrogen-gaseous sulfur reactions, the order of catalytic activity seems to follow generally the order of the pure metals themselves as found for other processes involving activation of molecular hydrogen.