METHOD OF MAKING CHEMI-MECHANICAL PULP FROM HARDWOOD

摘要

Manufacture of chemi-mechanical pulp from hardwood intended for wood-containing printing paper, especially wood-containing fine paper. The wood material in the form of chips is impregnated in one or two steps at a temperature below 80 DEG C with 15-40 kg NaOH and 0-30 kg Na2SO3 per ton pulp. Thereafter the chips are refined under pressure, so that the temperature of the chips prior to the refining does not exceed 80 DEG C for a time longer than ten seconds. Bleaching of the pulp with peroxide, at which bleaching at least 15 kg NaOH per ton pulp is charged additionally, so that the total amount of NaOH charge is 30-80 kg per ton pulp. After the bleaching a second refining step is carried out.