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介绍了硫酸盐桉木浆的氧脱木素、一段、二段和终段漂白工艺的发展,探讨了钼盐催化H2O2漂白和甲醛助漂白等新兴技术。己烯糖醛酸含量高和选择性差的浆料在经一段或两段氧脱木素后,卡伯值仅可降低至9～10,而在氧脱木素后使用钼盐催化的H2O2漂白可使浆料的卡伯值进一步降至3～4。1kgCOD/t绝干浆可消耗相当于0.085%的有效氯,因此,氧脱木素后的有效洗涤可节约漂白成本。A/D-(EP)-D三段漂流程即可满足硫酸盐桉木浆的漂白要求。不同类型浆料的有效氯用量从3.2%～7.7%不等。ECF漂白流程对漂白化学品用量的影响很小。热酸或高温ClO2漂白可为可漂性好的浆料节约少量的有效氯,但是对可漂性差的浆料却无此效果。硫酸盐桉木浆漂白的EP段采用常压抽提即可。甲醛在D1段加入比在D0/DHT中加入可节约更多ClO2。终段漂白采用H2O2漂白可改善浆料白度的稳定性。采用高温ClO2漂白可使有机氯化物用量减少30%,但这一效果在废水生物处理后就会消失。
The development of oxygen delignification, first stage, second stage and final bleaching process of kraftwood pulp was introduced. New technologies such as bleaching of H2O2 by molybdenum salt and bleaching of formaldehyde were discussed. After one or two stages of oxygen delignification, the kappa number of the hexene uronic acid-rich and poorly selective pulp can only be reduced to 9-10, and the use of molybdenum salt-catalyzed hydrogen peroxide bleaching after oxygen delignification Can further reduce the kappa number of the slurry to 3 ~ 4.1kgCOD / t dry pulp can consume equivalent to 0.085% of the available chlorine, therefore, the effective washing after oxygen delignification can save bleaching costs. A / D- (EP) -D three-stage drift flow to meet the bleaching requirements of eucalyptus sulfate pulp. The effective chlorine dosage of different types of slurries ranged from 3.2% to 7.7%. The ECF bleaching process has little effect on bleaching chemicals. Hot acid or high temperature ClO2 bleaching can save a small amount of available chlorine for bleachable pulp, but not for pulp with poor bleachability. Eucalyptus pulp bleached EP segment can be extracted using atmospheric pressure. Formaldehyde can be added more than D1 in D0 / DHT to save more ClO2. Bleaching of the final stage with H2O2 bleaching can improve the stability of the whiteness of the slurry. The use of high-temperature chlorine dioxide bleaching can reduce the amount of organic chloride by 30%, but this effect will disappear after wastewater biological treatment.