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该文探讨了氢氧化镁代替氢氧化钠作为桉木漂白化学热磨机械浆(BCTMP)过氧化氢漂白碱源的优缺点。所研究的工艺参数包括过氧化氢、碱和硅酸盐的用量以及反应温度和漂白时间。结果表明:在中浆浓体系下,过氧化氢用量一定时,应用氢氧化镁作碱源,漂后浆的白度比应用传统氢氧化钠的明显下降,尽管增加漂白时间和温度会显著缩小该差异;在高浆浓体系中,应用氢氧化镁作碱源,提高漂白温度和延长时间可以使漂后浆的白度显著增加,当过氧化氢用量分别为2.5%、4.0%和6.2%时,漂后浆的白度分别为76.9%ISO、80.8%ISO和83.2%ISO。这表明在过氧化氢用量相同并最佳用量条件下,氢氧化镁作碱源的漂后浆的白度与传统氢氧化钠作碱源时相近;当漂后浆的白度相同时,与采用氢氧化钠作为碱源相比,氢氧化镁为碱源的漂白工艺产生的阴离子垃圾和COD显著降低,得率增加。
This paper explores the advantages and disadvantages of magnesium hydroxide instead of sodium hydroxide as bleached chemical mechanical milling (BCTMP) hydrogen peroxide bleaching alkali source for eucalyptus wood. The process parameters studied included amounts of hydrogen peroxide, alkali and silicate as well as reaction temperature and bleaching time. The results showed that when the amount of hydrogen peroxide was constant, the magnesium hydroxide was used as the alkali source in the medium consistency system. The whiteness of the bleached pulp after bleaching was significantly lower than that of the conventional sodium hydroxide, though the bleaching time and temperature could be significantly reduced In the high consistency system, using magnesium hydroxide as alkali source, increasing the bleaching temperature and prolonging time can significantly increase the whiteness of bleached pulp. When the dosage of hydrogen peroxide is 2.5%, 4.0% and 6.2%, respectively, , The whiteness of the bleached pulp was 76.9% ISO, 80.8% ISO and 83.2% ISO, respectively. This indicates that under the same dosage of hydrogen peroxide and the best dosage, the whiteness of the bleached pulp with magnesium hydroxide as the alkali source is similar to that of the traditional sodium hydroxide as the alkali source. When the whiteness of the bleached pulp is the same, Compared with sodium hydroxide as the alkali source, magnesium hydroxide as a source of bleaching anaerobic process waste and COD significantly reduced, the yield increased.