COREFINING OF WOOD CHIPS AND RECOVERED PAPER IN CHEMITHERMOMECHANICALPULPING

Corefining of the black spruce chips with xerographic recovered paper was conducted using a chemithermomechanical pulping (CTMP) process. Re placing 15% of wood chips by recovered paper in the form of small shee ts in a CTMP with 3% Na2SO3 resulted in substantial improvements in st rength properties and a small reduction in optical properties when com pared to the 100%-chip CTMP counterpart. There was no apparent adverse effect on fiber length, and no excessive fines were observed in this study. The results of this exploratory work indicated that there may b e practical application of the corefining technique for producing news print furnishes. However, further studies are needed to better underst and the corefining mechanism.