The influence of green liquor and anthraquinone-modified kraft pulping on hexenuronic acid and carboxylic acid group contents in high lignin pulps

摘要

The influence of the pretreatment level of mill green liquor, pretreatment time, AQ, kraft pulping, AA dosage, and H-factor on hexenuronic acid (HexA) and carboxylic group content for a kraft pulp were studied for a series of high yield kraft pulps. In intermediate yield linerboard grade kraft pulping, the HexA content increases for aggressive green liquor pretreatment and kraft pulping. However, the carboxylic group content increases initially and then decreases with increasingly aggressive pretreatment and kraft pulping conditions. At the same delignification level, conventional kraft pulp has more HexA than both green liquor and green liquor/AQ-modified kraft pulps.