Papermaking chemicals are essential chemical substances used in various stages of the papermaking industry to treat fiber raw materials, pulp, and finished paper. They are mainly divided into two categories: common chemicals and fine chemicals.
Common Chemicals:
- Sodium hydroxide and sodium sulfide: Essential in sulfate pulping processes, used to convert fiber raw materials such as wood into pulp.
- Liquid chlorine and calcium hypochlorite: Commonly used in pulp bleaching, removing pigments from the pulp through chemical reactions, resulting in whiter paper.
- Rosin and aluminum sulfate: Used as binders in paper sizing processes, enhancing the paper's water resistance and strength.
Fine Chemicals:
Sulfuric acid: Added during pulp bleaching, it reduces cellulose degradation, thus maintaining paper strength. It is a special chemical substance added to meet specific needs.
It is important to note that the classification of chemicals is not absolute. Some fine chemicals may become routinely used chemicals over a long period, while ordinary chemicals may be modified to develop into fine chemicals with special properties. The types and applications of chemicals used in papermaking are diverse and dynamic. Together, they form the chemical basis of paper production and drive technological progress in the papermaking industry.
