ELECTROCHEMICAL DEGRADATION OF ALKALINE C OAL SLURRY WITH AN ELECTRONMEDIATOR

Coal degradation by anodic oxidation using an electron mediator was st udied for alkaline coal slurry. To oxidize a coal effectively with ins ignificant oxygen generation, a suitable mediator system was sought on the basis of experimental results of redox potential of coals and an anode potential at which oxygen was generated. The experimental result s showed that a redox couple Fe (CN)6(3-) + e = Fe(CN)6(4-) mediated e ffectively electrolysis of an alkaline slurry of Taiheiyo coal and was found to be suitable as the mediator system. To know whether or not t he mediator system can be applied to other coals, the rate of a chemic al reaction step involved in the anodic coal oxidation was studied for various coals. The results showed that the rate of the chemical react ion step decreased with higher rank coals. Thus, the present mediator system was suggested to be efficient for relatively low rank coals.