Manufacture of Bleached Pulp from Recycled OCC Linerboard, 1996 Pulping Conference Proceedings

Sunyoung Lee

W. T. McKean

R. R Gustafson

University of Washington

This project investigated various alkaline pulping methods to convert OCC into a bleachable grade fiber thereby upgrading its value. OCC linerboard was pulped by soda, kraft, soda-anthraquinone (AQ), and soda-oxygen pulping methods. It was found that the addition of AQ (0.05-0. 1%) to soda pulping resulted in faster delignification and greater yield compared to that obtained by the kraft and soda processes. All pulps responded similarly to elemental chlorine free bleaching (ECF). They all had brightnesses from a DEpDD bleaching sequence in the range of 8l-84%. There were some differences in the physical properties of the unbleached and bleached pulps produced by the various methods. Soda and alkali-oxygen pulping gave slightly weaker pulps. Soda-AQ and kraft yield pulps with similar burst and tear strengths. Soda-AQ pulp, however, produced pulp with a higher viscosity and a higher tensile index. Low tear strengths usually seen in soda-AQ pulping were not observed in this study. Soda-AQ pulping looks like a promising method of producing a bleachable grade fiber from OCC.