Comparison of pulping and bleaching behaviors of some agricultural residues

Abstract

The present study determines the characteristics of bleaching and beating of annual plants and agricultural waste, whichconstitute important raw material potential for the pulp and paper industry in Turkey. It also examines the efects of this process onseveral paper properties. Firstly, chemical contents are determined for each raw material and then evaluated for use in the pulp andpaper industry. All raw materials studied are found to be suitable for use in the pulp and paper industry, according to the determinedchemical content. Secondly, pulp with diferent properties is obtained and subsequently pretreated with the enzyme xylanase. It is thenbleached using the elementary chlorine-free (ECF) method, utilizing the DEpD bleaching sequence, which is both easy to apply andhighly efective. Te bleaching behavior of each material is then determined. Te highest ISO brightness value of 98.3% is obtainedusing soda-AQ pulps deriving from rye straw. Tis is followed by wheat straw (92.0%), reed (88.6%), corn stalks (87.6%), and ricestraw (87.5%). Each unbleached pulp sample is beaten at a constant 3000 revolutions PFI (9000 rev. for hemp), and changes in freenessproperties are determined. Te hardest material to beat is hemp fbers, followed by reed, rye, corn, and cotton stalks. Te best beatablepulps are rice straw, tobacco, wheat, sunfower, and barley stalks. Paper sheets from both unbleached and bleached pulps are tested.