Effect of birch kraft pulp primary fines on bleaching and sheet properties

Abstract

By removing the primary fines from an oxygen-delignified mill birch pulp, a fiber fraction was obtained having low metals content and no extractives. After DEDeD bleaching the fiber fraction had somewhat higher brightness and better brightness stability than the birch pulp containing the primary fines. The fines fraction was enriched with lignin, extractives, xylan, and metals. Bleaching the fines fraction in a QQP sequence did not affect the extractives, whereas a ZeQP sequence clearly reduced the extractives content. In a biorefinery concept, the fines fraction could be utilized as a source of xylan, fatty acids, sterols, and betulinol. Another possibility is to use the fines fraction unbleached or separately bleached as a bonding material in various fiber furnishes.

Potential of fines as reinforcing fibres in alkaline peroxide pulp of oil palm empty fruit bunch

“…The increase in brightness as a result of adding fines is a signal of good reaction between peroxide and fines. This suggests the predominance of surface lignin, to which peroxide is prone (Asikainen et al 2011). The findings therefore map surface lignin as residing in the fibrillated vessel elements and fibrils (Figs.…”