3. Chemical cooking of wood

3.1 General aspects

As mentioned above, the chemical cooking of wood extracts more than 90% of the lignin from the fibers and eliminates almost all the mineral and organic extractives initially present in the wood. The counterpart is the dissolution of a significant quantity of polysaccharides, mainly hemicelluloses, and partial depolymerization of cellulose. The parameters used to control the cooking process are the reagent load and the liquor/wood ratio, which determine the concentration of reagents, as well as the time taken for the temperature to rise and the duration of the stage. The quality of the resulting pulp is measured by two main control parameters:

1) The kappa index (KI) (see Norms and standards in the For further information section): this is...