Volume 05, Number 3
Jul 1992

Mill Conversions

Boise-Cascades' mill in Rumford, Maine, makes publications papers--coated groundwood (i.e., mechanical pulp), 38-45 lb.--on Machine #15, which is the fastest, widest coated paper machine in North America. Since 1989, #15 has been using what is called the "pseudo-alkaline process," which must be like the "pseudo-neutral process" described by John Penniman on p. 35 of the August 1991 issue of this Newsletter. It involves the use of calcium carbonate together with mechanical pulp, which used to be considered impossible. They do it by using alum judiciously to give the slurry a higher charge, without letting the pH get below 6.5.