Title
Elemental chlorine free bleaching of wheat straw chemimechanical pulp
Authors
AHMAD JAHAN LATIBARI MOHAMMAD ALI HOSSEIN REZA HOSSEINPOUR and AJANG TAJDINI

Received October 3, 2012
Published Volume 48 Issue 1-2 January-February
Keywords wheat straw, CMP, yield, strength, totally chlorine free, elemental chlorine free

Abstract
Production of bleachable CMP pulp from wheat straw using different dosages of NaOH and chemical treatment time was investigated. The yield after chemical treatment varied between 64.6 and 72.7% and the total yield after defiberizing was measured between 53.4% and 62%. The pulp produced applying 10% NaOH, 40 minutes pulping time and 95 °C pulping temperature was selected for bleaching trials. Elemental Chlorine Free (ECF) bleaching sequence was used for bleaching the selected pulp. Applying 3% (based on oven dry weight of the unbleached pulp) chlorine dioxide in D0EPD1 bleaching sequence (2% in D0 stage and 1% in D1 stage) improved the brightness to 62.2% ISO. The kappa number of the ECF bleached pulp was reduced from the value of 40.1 to the final value of 13.4 for bleached pulp.