Cooking and TCF Bleaching of Pine Employing On-Site Alkali Production, 1996 Pulping Conference Proceedings
Antero Varhimo, Osmo Pekkala, Marjatta Ranua and Olli Vältttilä
The Finnish Pulp and Paper Research Institute (KCL)
A laboratory-scale study was conducted to produce TCF bleached kraft pulp simulating a process in which all the alkali needed for cooking, oxygen delignification and TCF bleaching is produced internally. Using theoretically calculated alkali charges for the different process stages there were no problems in producing fully bleached TCF pulp of good quality. The good quality of the pulp is attributable to the process scheme, in which sulphide-rich mother liquor from the separation of sodium carbonate from green liquor is used in the impregnation stage of cooking. The separated carbonate is causticized and used in the other process stages. The new process means an increase of 20-30% in inorganic load to the recovery cycle depending on the process alternative chosen.
Cooking and TCF Bleaching of Pine Employing On-Site Alkali Production, 1996 Pulping Conference Proc