木荷、栲树、米槠三种阔叶木混合KP浆的多段漂白研究

Multi-Stage Bleaching of Kraft Pulps Made from a Mixture of Chinese Hardwood Species

本文叙述了福建产木荷、栲树和米槠三种阔叶木混合硫酸盐蒸煮浆(1∶1∶1)多段漂白的研究及其结果,本试验找出了各种硬度浆用三种漂白方法的适宜漂白条件,以及各因素对漂白结果的影响。

A kraft cook was prepared from a mixture of three different species of Chinese hardwood, viz, Muhe (Schma Superba Gardm et Champ.), Kaoshu (Castanopsis forgesiih Franch) and Mizhu (Castanopsis Carlesii(Hemsl) Hayata), in equal proportions. Kraft pulps thus made were bleached to 85-87% bright. ness either with C_DED, HDED or ODED. With CDED, most of chloro-lignins formed in the CD stage were water-soluble, bringing potential threats to the environment. Lower bleaching chemical consumption and less polution were claimed for the ODED sequence, but higher steam consumption was observed. Furthermore, more complicated process equipments were necessary for ODED treatment. Compared with CDED and ODED, HDED bleaching was favored for its maximun pulp strength, requiring less complicat. ed process equipments than ODED and lower effluent pollution than C_DED. Optimization of all three bleaching sequences for various final kappa numbers were investigated. The effects of various bleachig variables were discussed.