Production of Sulfate Pulps from Cardoon (Cynara cardunculus L.). The effect of Chipping of Pulp Quality

Abstract

In the utilization of cardoon (Cynara cardunculus L.) to produce sulfate pulps the cooking conditions and the chip size are the factors that determine the final pulp quality. The aim of this work is to stablish the range of cooking variables that produce good delignified pulps and to study the effect of chip size on the pulp quality. The results have shown that cooking time not inferior than 90 min (30 up to 170° C plus 60 at 170° C) and 16 % active alkali) are neccesary to obtain good delignified pulps. Chipping into a small size (1.7 cm) greatly improves delignification with no negative effect on paper quality. Cardoon sulfate pulps refine easily and showed good mechanical properties, although they present drainage difficulties and an extremely low porosity. So, it is neccesary to go into a procedure to dephithing that avoid the problems caused by the high fines content.