Alternative raw materials and their effect on pulp dewatering and paper properties

The effects of different materials on pulp dewatering and paper properties of recovered and virgin pulp were investigated. A matrix with non-technological data that include price, availability, seasonality, solids content, and composition of alternative raw materials, was created. The alternative materials were added in proportions of 5%, 10% and 15% to two reference pulps that include recovered pulp used for fluting in a Dutch paper mill, virgin wood-pulp from another Dutch paper mill, supplied in the form of dry fiber pads. Several methods and tests that were applied to fully investigate and describe dewatering of pulp stock mixed with the alternative materials include Schopper-Riegler (SR) according to ISO 5267-1 and hydrodynamic specific surface Area (HSSA) assessment. Other methods include Rapid-Ko¨then (RK) number, water retention value (WRV), and FiberXPress test. The results of WRV tests showed that all of the five tested alternative materials improve the dewatering of pulp after the press section. (11 refs.)