| 摘要 |
paper-and-pulp industry. SUBSTANCE: chip is steamed, ground in two steps involving chemical treatment, and bleached. Between the two steps, paper production scrap with ash content 2 to 20% and grinding degree 40 to 80 deg. is added to pulp in proportion 10 to 50% of the weight of absolutely dry chip. Chemical treatment may be performed with sodium sulfite, sodium bisulfite, magnesium bisulfite, sodium hydrosulfite, sodium hydroxide, aqueous solution of hydrogen peroxide, or with mixtures of indicated reagents. EFFECT: increased degree of opacity with no loss in mechanical strength. 2 cl, 1 tbl, 4 ex
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