Leaching of Raney Ni-A1 alloy with alkali: kinetics of hydrogen evolution

Abstract

Kinetics of leaching of Raney Ni-AI alloy (Ni: 50% w/w) with alkali has been studied in an agitated reactor by measuring the rate of H₂ evolved in the leaching process at constant alkali concentrations. The effects of various process parameters such as temperature, type and concentration of alkali, particle size of the alloy and stirring speed, on the leaching process have also been investigated. The kinetic data could be fitted to the empirical expression ¦ q= α+βlog(t). Where, q is the amount of H₂ evolved in the leaching process; t, the reaction time; and a and β, the constants. The order of reaction with respect to alkali concentration and the activation energy for the leaching process were determined from the analysis of the initial rates. An appreciable fraction of the hydrogen, which is formed in the leaching process, has been found to be retained on the solid product(s).