Pulping and biorefining
- General approach and principles
- Extraction-based methods
- Separation of valuable extractives from trees
- Choosing the right solvent – hydrophobic or hydrophilic?
- Stemwood extractives-based products
- Operation modes and procedures in industrial extraction processes
- Exudate gums and latexes
- Hot-water extraction
- Wood extractives – general description
- Factors contributing to the loss of extractives
- Chemical changes in extractives during storage
- Bark extractives – terpenes and terpenoids
- Bark extractives – polyphenols and other minor compounds
- Use of deep eutectic solvents (DES)
- Chemical and biochemical conversion
- Thermochemical conversion
- Kraft pulping
- Wood material handling systems
- Pulping process-general approach
- Pulping technologies
- Drying of chemical pulps
- Chemical (market) pulps drying plant applications
- Recovery of cooking chemicals and by-products
- Integrated biorefinery concepts
- Oxygen-alkali delignification
- Delignifying or lignin-removing bleaching
- Other delignification methods
- Mechanical pulping
Delignifying or lignin-removing bleaching Bleaching can basically be defined as a chemical process applied to chemical and mechanical pulps in order to increase their brightness.1 Thus, to reach an acceptable brightness level, bleaching should be performed either by removing the coloured residual lignin of chemical pulps (“delignifying or lignin-removing bleaching”) or by converting and stabilising
Authors & references
Author:
Raimo Alén, University of Jyväskylä
References
- Alén, R. 2000. Basic chemistry of wood delignification. In: Stenius, P. (Ed.). Forest Products Chemistry. Fapet Oy, Helsinki, Finland. Pp. 58−104.
- Chirat, C., Hostachy, J.-C., Paloniemi, J., Pelin, K., Pohjanvesi, S., Nordén, S., Vesala, R. and Wennerström, M. 2011. Bleaching. In: Fardim, P. (Ed.). Chemical Pulping Part 1, Fibre Chemistry and Technology. 2nd edition. Paper Engineers’ Association, Helsinki, Finland. Pp. 457−599.
- Gierer, J. 1970. The reactions of lignin during pulping. Svensk Papperstidning 73:571–595.
- Lachenal, D., Benattar, N., Allix, M, Marlin, N. and Chirat, C. 2005. Bleachability of alkaline pulps. Effect of quinones present in residual lignin. Proceedings of 13th ISWFPC, Vol. 2. Auckland, New Zealand, May 16-19, 2005. Pp. 23–27.
- Karlsson, O., Pettersson, B. and Westermark, U. 2001. The use of cellulases and hemicellulases to study lignin-cellulose as well as lignin-hemicellulose bonds in kraft pulps. Journal of Pulp and Paper Science 27(6):196–201.
- Gellerstedt, G. and Gierer, J. 1971. The reactions of lignin during acidic sulphite pulping. Svensk Papperstidning 74:117–127.
- Lachenal, D. and Muguet, M. 1992. Degradation of residual lignin in kraft pulp with ozone. Application to bleaching. Nordic Pulp and Paper Research Journal 7(1):25–29.
- Singh, R. P. (Ed.). 1991. The Bleaching of Pulp. 3rd edition. TAPPI Press, Atlanta, GA, USA. 694 p.
- Dence, C. W. and Reeve, D. W. (Eds.). 1996. Pulp Bleaching – Principles and Practice. TAPPI Press, Atlanta, GA, USA. 868 p.
- Suess, H. U. 2010. Pulp Bleaching Today. Walter de Gruyter, Berlin, Germany. 310 p.
- Bajpai, P. 2012. Environmentally Benign Approaches for Pulp Bleaching. 2nd edition. Elsevier, Amsterdam, The Netherlands. 416 p.
- Bajpai, P. 2013. Bleach Plant Effluents from the Pulp and Paper Industry. Springer, Heidelberg, Germany. 88 p.
Videos
Exercises
This page has been updated 08.01.2021