EFEITOS DA XILANA NA PRODUÇÃO DE CELULOSE DE EUCALIPTO

CERNE

Colodette, Jorge Luiz¹  Barbosa, Bianca Moreira¹  Muguet, Marcelo Coelho dos Santos²  Gomes, Valéria Juste¹  Oliveira, Rubens Chaves de¹ 

[1] Universidade Federal de Viçosa, Viçosa, Brasil$$;Klabin S/A, Pesquisa e Desenvolvimento, Paraná, Brasil$$

关键词: Redeposition of xylans;    Kraft pulping;    Pulp and paper.;   

DOI  :  10.1590/01047760201622022102

来源: Universidade Federal de Lavras-UFLA

【 摘 要 】

The search for a better use of wood in the pulp industry has fuelled interest in a more rational use of its components, particularly xylans. The impact of xylans removal and of xylans redeposition on pulp properties for tissue and P&W paper grades are discussed in this paper. Kraft pulp (15.6% xylans) treatment with 10-70 g.L-1 NaOH resulted in pulps of 14.5-5.9% xylans. The treatments decreased pulp lignin and HexA contents and caused significant positive impact on subsequent oxygen delignification and ECF bleaching. Xylan removal decreased pulp beatability, water retention value and tensile index but increased drainability, water absorption capacity, capillarity Klemm and bulk. Overall, xylan depleted pulps showed almost ideal properties for tissue paper grade pulps. In a second step of the research, xylans extracted from unbleached (BXL) and bleached eucalyptus pulps (WXL) by cold caustic extraction (CCE) were added to a commercial brown pulp in the oxygen delignification (O-stage) and further bleached. Xylans deposition occurred at variable degree (up to 7% on pulp weight) depending upon the O-stage reaction pH. Pulp bleachability was not impaired by WXL xylan deposition but slightly negatively affected by BXL xylans. Pulp beatability was improved by xylan deposition. The deposited xylans were quite stable across bleaching and beating, with the WXL xylans being more stable than the BXL ones. At low energy consumption, the deposited xylans improved pulp physical and mechanical properties. Xylans extraction by CCE with subsequent deposition onto pulp in the O-stage proved attractive for manufacturing high xylan P&W paper grades.

【 授权许可】

Unknown