Electrochemical delignification of a softwood kraft pulp with in-situ generation of a catalyst

In-situ electrochemical delignification of a softwood kraft pulp was examin ed in electrochemical cells. An efficient mass transfer in an electrochemic al cell showed improved delignification and bleaching efficiencies at pulp consistencies above 3 %. Delignification of pulp with electrochemically gen erated ferrocyanide catalyst reduced kappa number by about 50 % at 25 degre es C within a time period of less than one hour. The effect of catalyst con centration, current density, alkali charge and time of delignification has been examined. Electrolyte solution after delignification is recyclable and produces low effluent load in wash filtrate.