| 摘要 |
FIELD: paper-and-pulp industry. ^ SUBSTANCE: invention is directed to preparing secondary fiber and can particularly be used in manufacture of paper and cardboard. Method comprises pulping of secondary fiber in presence of alkali metal hydroxide, sodium silicate, hydrogen peroxide, to which phosphorus-containing acid compound is added. The latter is selected from group consisting of sodium polyphosphate and sodium phosphate. Consumptions of sodium silicate, hydrogen peroxide, and phosphorus-containing acid compound are, respectively, 0.5-2.0%, 0.5-2.0%, and 0.1-1.0% based on the weight of dry fiber. ^ EFFECT: improved whiteness of fibrous material. ^ 1 tbl, 4 ex |
