Chlorine dioxide multi-step bleaching method of linseed pulp

Abstract

The invention provides a chlorine dioxide multi-step bleaching method of linseed pulp, in particular to a method for carrying out chloride dioxide multi-step bleaching on the linseed pulp obtained by cooking through the ammonium sulfite method. The method comprises the processes of carrying out oxygen delignification and chloride dioxide bleaching, oxygen and hydrogen peroxide reinforced alkalineextraction and chlorine dioxide additional bleaching on the linseed pulp obtained by cooking through the ammonium sulfite method. By the reasonable combination of the technical route and technical parameter, the pollution load of the bleached wastewater is lowered and the influence of the bleaching process on the environment is reduced which the whiteness of the bleached linseed pulp is greatly improved.

Description

technical field [0001] The invention belongs to the pulp bleaching technology in the field of papermaking, and in particular relates to a method for multi-stage chlorine dioxide bleaching of flax pulp obtained by cooking with ammonium sulfite. Background technique [0002] Flax belongs to the hemp family, the genus Flax, also known as flax, is a kind of grass plant fiber raw material with long fibers, and is called flax in Northwest China (Gansu and other places). The physical properties and mechanical strength of flax pulp are equivalent to those of softwood pulp, and it also makes up for the shortcoming of short xylem fibers. In particular, flax pulp has a high tear index, good air permeability, and no odor when burned. It is widely used as papermaking Raw materials, especially high-quality raw materials for the production of high-grade cigarette paper. [0003] At present, the alkaline method is mostly used to make pulp from flax raw materials, but the flax pulp obtained...

AI Technical Summary

Problems solved by technology

This method is to use the combination of chlorine bleaching and hydrogen peroxide bleaching and the treatment of special activator S to achieve the effect of improving whiteness. It can be seen that in addition to the need for activator, the process requires less chlorine and hydrogen peroxide. Relatively large, while obtaining high-brightness pulp, the large chlorine consumption not only increases the cost of bleaching, but also makes the bleaching wastewater contain a large amount of organic chlorides, such as dioxins and other toxic substances, causing great harm to the environment the harm of

On the other hand, although this method uses hydrogen peroxide bleaching, it still needs to use S activator to activate the lignin and chromophoric groups that affect the brightness of pulp, which also increases the cost of the bleaching process.

[0006] Although chlorine dioxide bleaching technology is a well-known technology in the art, it is mainly used for the bleaching of wood pulp. For example, Chinese patent application 90109504.4 discloses a kind of high-efficiency chlorine dioxide pulp bleaching method. In the process, how to design the bleaching process to determine the effective amount of chlorine dioxide, and reduce the amount of chlorine dioxide while obtaining high-brightness pulp, but this method is only for the wood pulp bleaching process. Once the raw material changes, the bleaching process requirements will inevitably Change

[0007] There is no technical report on bleaching flax ammonium sulfite pulp with chlorine dioxide

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