ELECTROCHEMICAL COUPLE BEHAVIOR OF MANGANESE DIOXIDE WITH FERROUS/FERRIC IONS IN ACIDIC CHLORIDE MEDIUM

摘要

The electrochemical couple behavior of manganese dioxide with ferrous/ferric ions in acidic chloride medium was investigated. It was proven that the dissolution of MnO_2 is due to the electrochemical couple reaction between MnO_2Mn~(2+) and Fe~(2+)/Fe~(3+) in the solution. The driving force for the process originates from the rest potential difference of the two couples. The reduction of MnO_2 is controlled by electrochemical kinetics, whereas the conversion of Fe~(2+) to Fe~(3+) is limited by diffusion. The factors such as the Mn~(2+), Fe~(2+), Fe~(3+), Cl~- concentration, pH of the solution and the temperature, have much influence on the kinetics of the couple process. This study will be useful to elucidate the mechanism for the leaching of manganese nodule from the deep ocean as well as manganese dioxide ores in land.