Effect of alkaline charge on pulping parameters of Cryptomeria japonica wood

The Cryptomeria japonica is a conifer, from Japan, with the potential for pulp production, but little is known about their behavior when subjected to different reagent loads. Thus, the objective of the study was to evaluate the effect of the alkaline charge on the kraft pulping parameters of Cryptomeria japonica wood, in order to understand its chemical demand to obtain different delignification levels. For this, we used the wood from trees with 13 years old, which was characterized as to the basic density, chemical composition and tracheids morphology and subjected to cooking curves with different levels of alkali, ranging from 14 to 28%. The pulp and black liquor obtained were evaluated in order to understand the effect of the alkaline charge on them. Based on the results obtained in the cooking curves, applying different alkaline charges, it???s concluded that the Cryptomeria japonica wood is more suitable for producing unbleached pulp of long fiber. This is because of its wood present high lignin content, which complicates the delignification process, and low basic density, resulting in low yield. Thus, to optimize the use of this species, it???s more indicated to work with pulp with high kappa number, which is possible to combine a good pulp yield.