THE APPLICATION OF AN ECONOMIC AND EFFECTIVE SELECTIVITY CHEMICAL SYSTEM FORIMPROVING OXYGEN DELIGNIFICATION IN A MILL SETTING

摘要

Oxygen delignification (OD) of low kappa softwood kraft pulp was examined in two steps without washingbetween interstage as part of an overall program to evaluate the suitability of a novel selectivity enhancementsystem. Approximately 6.5% black liquor carryover was in the reaction system, but did not affectdelignification and the selectivity of the OD reactions. The residual lignins from both the original pulp andoxygen delignified pulp, namely RL and RL-O, respectively, and lignin in residual alkali solution after oxygendelignification, namely SL-O were prepared and were characterized using NMR spectroscopy to provide a basisfor the rationalization of the selectivities observed. The low molecular weight compounds dissolved in alkalisolution were also characterized by GC-MS spectroscopy.