line decor
line decor

Bookmark and Share Print this Page Print this page Email this Page Email this Page

papermaking process BACK TO DIAGRAM
CHEMICAL PULPING PROCESS


Chips from the storage bins are fed into a digester to which chemicals have been added. The woodchips are then 'cooked' to remove lignin. Lignin is the binding material which holds the cellulose fibres together.

The chips are 'cooked' by heat and pressure in caustic soda and sulphur.

The chemical process is energy self-sufficient as nearly all by-products can be used to fire the pulp mill power plant. The chemical pulping process produces lower fibre yield than mechanical pulping, typically 50-60%.

 

 
 

 
......© Confederation of Paper Industries, 1 Rivenhall Road, Swindon, Wiltshire SN5 7BD