A preliminary study on the production of linerboard materials from green liquor-anthraquinone pulping of US southern softwood

Laboratory scale kraft pulping of Pinus taeda (US Southern loblolly pine) wood chips were performed using industrial and lab-made "green liquor" to provide liner-grade pulps using the unique approach of employing green liquor and anthraquinone (AQ) to procure gains in efficiency of manufacture. Using mill green liquor, the resulting kappa numbers of the pulps at high AQ dose ranged from about 81 to 67. The lower AQ dose produced pulps with kappa numbers in the range of about 94 to 71. The cooks with lab-made green liquor demonstrated an even higher delignification relative to the mill green liquor cooks. This latter effect could be explained by differences in effective chemical composition of the liquor for the two types of cook. Overall these preliminary results indicate strong potential for green liquor pulping for linerboard pulps.