Alkaline bleach liquor extraction process of bamboo wood dissolving pulp

Abstract

The invention belongs to the technical field of the preparation of dissolving pulp, in particular to an alkaline bleach liquor extraction process of bamboo wood dissolving pulp, which comprises the following steps: A. washing and concentrating pulp bleached by chlorine dioxide, adding 1.2-1.8% of caustic soda, and adjusting the pH value of the pulp to be 10.5-11.0; B. after adjusting the pH value, feeding the pulp into a medium-concentrated stand tube, and adding 3-5kg / admt hydrogen peroxide; C. sending the pulp from the medium-concentrated stand tube into a medium-concentrated mixing device, and adding 3-5kg / admt of oxygen; D. sending the pulp from the medium-concentrated mixing device into an upflow tower, and then overflowing into a downflow tower, and the retention time of the pulp in the upflow tower and the downflow tower is for 75-100min, and the temperature is 80-85 DEG C; and E, pumping the pulp from the downflow tower to a pulp washing machine to wash and concentrate for standby. The alkaline bleach liquor extraction process disclosed by the invention has the advantages that the removal rate of residual lignin is high, the whiteness of the produced pulp is stable, the consumption of chemicals at a subsequent chlorine dioxide bleaching stage can be reduced, and the alpha-cellulose content in the pulp is improved.

Description

technical field [0001] The invention belongs to the technical field of preparation of dissolving pulp, in particular to an alkali extraction process of bamboo dissolving pulp. Background technique [0002] Dissolving pulp is widely used in textile viscose fiber, nitrocellulose, cellulose acetate and other cellulose derivative industries, and the market demand is gradually expanding. At present, the newly developed bamboo dissolving pulp has a broad market prospect and can fill the gap of dissolving pulp in my country. [0003] However, the existing bamboo dissolving pulp production equipment and technology are relatively backward, especially the traditional three-stage bleaching of C-E-H is mainly used in the bleaching process. The wastewater pollution load generated by the bleaching process is large, and there are internationally recognized carcinogens dioxin produce. [0004] In recent years, an improved ECF bleaching process has been adopted in China. The alkali extract...

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Problems solved by technology

[0003] However, the existing bamboo dissolving pulp production equipment and technology are relatively backward, especially the traditional three-stage bleaching of C-E-H is mainly used in the bleaching process. The wastewater pollution load generated by the bleaching process is large, and there are internationally recognized carcinogens dioxin produce

[0004] In recent years, an improved ECF bleaching process has been adopted in China. The alkali extraction process is indispensable in the ECF bleaching process. However, in the existing alkali extraction process, it is usually only a simple alkali treatment. The improvement of whiteness is not obvious, the consumption of chemicals in the chlorine dioxide bleaching process in the later stage is relatively high, and the cost of bleaching is relatively high