METHOD OF PREPARING SECONDARY FIBER IN PRODUCTION OF CELLULOSE-CONTAINING FIBROUS MATERIAL

摘要

FIELD: paper-and-pulp industry. ^ SUBSTANCE: invention is directed to preparing secondary fiber (waste paper) and can particularly be used in manufacture of paper and cardboard. Waste paper is subjected to pulping while simultaneously dispersing printing ink in presence of phosphorus-containing acid sodium salt followed by aluminum sulfate-induced precipitation conducted at pH 6.0-7.0. Pulping effected at 17-23°C for 20-30 min consumes amount of phosphorus-containing acid sodium salt, namely sodium polyphosphate or sodium phosphate, corresponding to 0.05-0.08% of the weight of dry fiber. ^ EFFECT: increased destruction force and improved whiteness of material. ^ 4 cl, 1 tbl, 5 ex