There are two commonly used methods of bleaching pulp, Chengzhi Industry will introduce to you below:
One is the oxidative bleaching method, which uses oxidative bleaching agents to destroy the structure of lignin and dissolve it to achieve the purpose of improving the purity and whiteness of the pulp. Such bleaching agents include C12, ClO2 and hypochlorite. At present, oxidative bleaching is still the main bleaching method. Oxidative bleaching agents are chlorine-containing bleaching, which causes serious pollution and will gradually be replaced by oxygen-containing bleaching methods.
The other is reductive bleaching, which uses reductive bleaching agents to change the structure of the chromophore and decolorize it. Because it will not cause the loss of fiber components and can maintain the characteristics of the original pulp, it is especially suitable for the bleaching of high-yield pulp such as groundwood pulp and chemical mechanical pulp. Such bleaching agents include zinc dithionite, sodium dithionite, hydrogen peroxide and sodium peroxide. The paper pulp bleached by reducing bleaching agent has poor whiteness stability and will return to its original color after prolonged exposure to light in the air.
Of course, in the practice of bleaching, one method cannot be used to bleach the pulp to a higher whiteness, and multiple bleaching methods are often used together, that is, the so-called multi-stage bleaching, such as three-stage bleaching, five-stage bleaching, etc., in order to make the pulp Bleached to meet the requirements of the use of whiteness.
Zhengzhou Chengzhi Industrial Co., Ltd. is a modern technology enterprise engaged in the research, development, production and sale of fine chemical and biological enzyme products. The main products of the company are: hydrogen peroxide stabilizer, oxygen bleaching intensifier, bleaching activator, hydrogen peroxide promoter, chelating agent, cooking aid, sewage decolorizer, sodium silicate substitute, etc. Welcome to consult and understand. Company website: http://www.paperchemicals.com.cn.