Patent ID: 6719879
Filing Date: 2004-04-13
Classification: C01F,C01P,C09C,D21C,D21H,Y02P

Abstract:
A method for obtaining particulate calcium carbonate product having an average particle size less than 12 microns, comprising the steps of:adding calcium to a recausticizing cycle of a kraft pulp mill at a rate greater than 25 percent by weight of the requirements of the recausticizing cycle; withdrawing from the kraft pulp mill an alkaline mixture containing calcium carbonate wherein the alkaline mixture containing calcium carbonate is withdrawn during the recausticizing cycle; treating the alkaline mixture containing calcium carbonate so as to remove contaminants contained in the alkaline mixture to thereby produce a treated alkaline mixture substantially free of contaminants and containing calcium carbonate; and recovering from the treated alkaline mixture a particulate calcium carbonate product having an average particle size less than 12 microns, wherein the treated alkaline mixture has been treated such that the particulate calcium carbonate product has a substantially neutral pH.