Book Description

Basic studies of the kinetics of the reduction of copper oxide were made to establish the effect of the solid phase on the over-all reaction kinetics The reaction CuO + H/sub 2/ at the only rea Cu + H/sub 2/O consisted of an induction stage, an acceleration or autocatalytic stage terminating at about 35% reduction of the exide, and a decreasing-rate stage The reduction rates for each stage were dependent on the nature of the initial oxide, the degree of subdivision of the oxide, and the temperature but were independent of the mass of the oxide phase. Addition of the reaction product copper had no measurable effect on the reaction. Water vapor in concentrations of 25 mg per liter of H prevented reduction at 112 ction prod- C The inhibiting effect decreased rapidly as the temperature was increased and disappeared entirely at 190 ction prod- C. Once reduction bad started. water vapor had practically no effect The acceleration and decay stages were very closely approximated by a semiempirical equation based on the initial reaction occurring on certain active nuclei followed by a rapid growth of these nuclei by a branching-chain mechanism. The reduction rate reached a maximum and subsequentlv decreased as considerable interference occurred among the branching nuclei. Arrhenius plots gave an activation energy- of 13.5 plus or minus 1.2);cal for the reduction. (auth).