PRESS ROLL PITCH DEPOSITION PROBLEMS ASSOCIATED WITH THE USE OF CERTAIN CLAY PRODUCTS IN NEWSPRINT MANUFACTURE

The practice of using 1-5% clay products in some newsprint-related gra des is accompanied sometimes by a sharp increase in pitch deposition o n press rolls and subsequent pitch problems. Chemical analyses of the deposits indicate elevated concentrations of sticky aluminum soaps. Re cent evidence suggests that tetrasodiumpyrophosphate (TSPP), used to d isperse and stabilize some clay slurries, can extract aluminum from cl ay and thereby make it available for the formation of sticky aluminum soaps. Laboratory experiments to determine the conditions under which these soaps are formed point the way to solutions for the press roll d eposition problems.