Caustic soda and paper pulping
Paper pulping ,there are wide range of chemicals which use in paper industry in another way its tell paper chemicals .Chemical usage is not only for imparting properties to paper but to handle the water cycles in the process, conditioning of fabrics, cleaning of equipment and several other applications.
why used caustic soda in paper pulping?
Preparing the pulp involves separating out the cellulose fibers from the plant material. Many plant materials are very tough and require boiling in sodium carbonate (soda ash) or caustic soda (lye) at ph 12-14 to accomplish.
Caustic soda is a key component of the white liquor solution used to separate lignin from cellulose fibers in the sulfate process. 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.
Caustic soda in Kraft pulping
Caustic soda also use in Kraft pulping process involves treatment of wood chips with a hot mixture of water, caustic soda , and sodium sulfide (Na2S), known as white liquor.
Caustic Soda in the Kraft process or Sodium Hydroxide in soda pulping are used to break the lignin bonds of wood being processed into pulp for papermaking. Using recycled chemicals as makeup from other sources (spent caustics) aids in the reduction of the environmental impact of chemical pulping.