@inproceedings{535c42166a094898b2d344fbd9f70bb4,
title = "Fate of metal cations in the kraft pulping process modified by phosphonates",
abstract = "Metal cation exchange with unbleached fibers was investigated using hardwood kraft pulps produced with phosphonate addition in the digester. Metal contents and their sorption by the dissolved kraft lignin in the black liquor were also quantified. Ion exchange constants for the calcium-sodium pair were determined. Reductions of Fe, Mn and Zn are most likely responsible for the brightness improvement of resulting pulps as well as their beneficial responses in subsequent bleaching. Metal-ions especially calcium on fibers are significantly decreased by-phosphonates addition in cooking; they eventually enter the black liquor and form soluble phosphonate-cation groups. Approximately 800-1000ppm of calcium was retained on fibers while less than 67ppm were found in precipitated kraft lignin. The overall solids content within the cooking system was increased by 0.6-1.3%.",
author = "Wei Li and Tschirner, {Ulrike W}",
year = "2003",
language = "English (US)",
isbn = "1930657307",
series = "TAPPI Fall Technical Conference",
pages = "373--392",
booktitle = "2003 TAPPI Fall Technical Conference",
note = "2003 TAPPI Fall Technical Conference: Engineering, Pulping and PCE and I ; Conference date: 26-10-2003 Through 30-10-2003",
}