METHOD FOR REDUCING CALCIUM SULFATE SCALE

摘要

PROBLEM TO BE SOLVED: To provide a method for reducing scales consisting essentially of calcium sulfate generated in a paper making machine; and to provide a method for reducing defects on a paper face caused by the scales of the calcium sulfate.;SOLUTION: The method for reducing the scales comprises adding at least one kind of inorganic coagulant selected from aluminum sulfate and polyaluminum chloride, and adding at least one or more kinds of organic polymer-based coagulants selected from a polyethyleneimine, a copolymer of a polydiallyldimethylammonium chloride and acrylamide, a copolymer of epichlorohydrin and dimethylamine, and a polyamine and having ≥3 meq/g charge density to a complete raw material, in the paper machine using the complete raw material at least containing an ink-removed pulp and/or a mechanical pulp, and providing a filtrate having ≥6.0×10^-5 product of a calcium ion concentration (mol/l) and a sulfate ion concentration (mol/l), and ≥50 μeq/l cation requirement.;COPYRIGHT: (C)2005,JPO&NCIPI