Soda-anthraquinone pulping of sunflower stalks

Soda-anthraquinone (soda-AQ) pulping of sunflower stalks increased the rate of delignification and the pulp yield, and improved the bonding strength p roperties at the lower active alkali consumption compared to soda pulping. The wet depithing of the stalks contributed considerably to the yield and s trength properties, together with decrease in alkali consumption and reject s. Addition of guar gum (0.5% on oven-dry pulp) during beating after reachi ng 25 degrees SR as wet-end/dry-strength agent, improved further the draina bility and strength properties. The soda-AQ pulping makes pulping of sunflo wer much more attractive and feasible once the other technical constrains s uch as the high pith content are overcome by employing recent techniques de veloped for other agricultural residues. (C) 1998 Elsevier Science B.V. All rights reserved.