Application in Paper Industry

There are about 3000 or so different types of chemicals which can be used in papermaking, in practice only about 200 individual chemicals are typically used, each satisfying a specific need. Some of the important chemicals used are: 

1) Caustic soda, sodium sulfide for the Kraft process, the process of conversion of wood into wood pulp consisting of almost pure cellulose fibre.

2) Sulfurous acid for the Sulfite process

3) Caustic soda, Anthraquinone for the Soda pulping

4) Caustic soda is added to increase the pH in the pulping process of fibers. The higher pH of the paper fiber solution causes the fibers to smoothen and swell, which is important for the grinding process of the fibers.

5) Sodium dithionite, chlorine dioxide, hydrogen peroxide, ozone for bleaching of wood pulp

6) Bleaching additives: sodium silicate

7) sequestering agents: EDTA, DTPA