Electrically augmented vacuum filter system for dewatering slurries

摘要

A system for dewatering a suspension of particulate solids e.g. hydrous kaolin clay comprises an electrically augmented vacuum filter of the known type (see US4168222) which has been modified by incorporation of a perm-selective membrane in the housing surrounding the anolyte chamber. - This membrane is pref. a perfluorosulphonic acid polymeric film and permits passage of cations from the anolyte into and through the filter cake and the suspension while preventing passage of anions and gaseous anolyte prods. A similar membrane may be incorporated into the catholyte chamber housing. - The system is esp. for use in dewatering hydrous kaolin clay slurries to about 70% solids for transportation. The membrane prevents contamination of the filter cake by undesirable species, e.g. hydroxyl ions which impart to the prod. an excessively high viscosity and low specific resistance. The prod. can be tailored to various end uses, e.g. in paper coating or paint formulation. EPAB- EP--84582 B A device for dewatering a suspension of particulate solids, such as hydrous kaolin clay using an electrically augmented vacuum filter apparatus comprising a tank adapted to receive and discharge suspension to be filtered, and anodic and cathodic electrode structures adapted to be positioned in said tank in a manner such as to be submerged in suspension in said tank, said anodic electrode structure being adapted for deposition thereon of filter cake and including an anodic element, electrically nonconductive housing for said anodic element and means for supplying anolyte into and out of said housing, said cathodic electrode structure including a cathodic element and being srrounded by a filter medium adapted for the passage thereghrough of filtrate, characterized in a perm-selective membrane associated with said anodic structure in a manner such as to permit passage of cations from said anolyte therethrough and into and through said filter cake and suspension to be filtered while substantially preventing passage of anions and gaseous electrochemical reaction products from said anolyte therethrough and into filter cake deposited on said anodic structure. (11pp) - EP--84582 B A device for dewatering a suspension of particulate solids, such as hydrous kaolin clay using an electrically augmented vacuum filter apparatus comprising a tank adapted to receive and discharge suspension to be filtered, and anodic and cathodic electrode structures adapted to be positioned in said tank in a manner such as to be submerged in suspension in said tank, said anodic electrode structure being adapted for deposition thereon of filter cake and including an anodic element, electrically nonconductive housing for said anodic element and means for supplying anolyte into and out of said housing, said cathodic electrode structure including a cathodic element and being srrounded by a filter medium adapted for the passage therethrough of filtrate, characterized in a perm-selective membrane associated with said anodic structure in a manner such as to permit passage of cations from said anolyte therethrough and into and through said filter cake and suspension to be filtered while substantially preventing passage of anions and gaseous electrochemical reaction products from said anolyte therethrough and into filter cake deposited on said anodic structure.