|
Title
TCF Bleaching of EUCALYPTUS UROPHYLLA x EUCALYPTUS GRANDIS LH107 oxygen-delignified kraft pulp - Partial Mg2+/Ca2+ substitution for chelants in the chelation stage
Authors
YUNXIA SHEN XUEFEI ZHOU and XIUJUAN LU
Received
May 6, 2010
Published
Volume 46 Issue 1-2 January-February
Keywords
E. urophylla × E. grandis LH107 kraft pulp, chelation, calcium acetate, magnesium acetate, totally
Abstract
The optimization of bleaching, following the sequence of chelation, peroxyacetic acid and hydrogen peroxide treatments of E. urophylla × E. grandis LH107 oxygen-delignified kraft pulp, was carried out and the optimal parameters were obtained. In the chelation stage, the effect of partial magnesium acetate and calcium acetate substitution for ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid was studied in terms of brightness and polymerization degree of the bleached pulp. It was evidenced that (magnesium acetate + calcium acetate)/ethylenediaminetetraacetic acid was optimal, compared to other treatments in the chelation stage, especially as no washing between (magnesium acetate + calcium acetate) and ethylenediaminetetraacetic acid treatments was necessary. This partial Mg2+/Ca2+ substitution for chelants in the chelation stage had a positive impact on totally chlorine-free bleaching, providing pulps with higher brightness and small loss of physical strength.
Link
|
