Preliminary studies on TCF bleaching of Pinus pinaster acetosolv pulps.
Oxygen pre-treatment of Pinus pinaster acetosolv pulps has been studied as a first step towards TCF bleaching. Using a 2(3) factorial design, the influence of temperature (80-120 degrees C), time (1-2 h) and NaOH concentration (1.5-3%) on pulp yield in the oxygen stage, chemical composition and physical properties of the pulps obtained was studied. Pulps pre-bleached with oxygen in the conditions selected as optimal (80 degrees C, 1 h with 2.25% NaOH) have been bleached with TCF sequences which included stages with hydrogen peroxide or hydrogen peroxide-oxygen under pressure. Even if high degrees of delignification were reached, with a reduction in Kappa number up to 95% and without important loss of viscosity, the carbohydrates degradation, especially hemicelluloses in the acetic acid delignification, reduces the strength potential of the pulps.
Vázquez
G
G
Faculty of Chemistry, Department of Chemical Engineering, University of Santiago de Compostela, Spain.
González-Alvarez
J
J
Rodríguez
E M
EM
Freire
S
S
Antorrena
G
G
D019342:Acetic Acid / Q000737:chemistry; D002482:Cellulose / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D014197:Trees / Q000737:chemistry*
D002482:Cellulose; D006861:Hydrogen Peroxide; D019342:Acetic Acid; D010100:Oxygen