Bleaching Mechanical Pulps

Mechanical pulp bleaching, 21 48-51 chelation in, 21 49 new developments in, 21 50-51 using weak alkali sources in, 21 50-51 Mechanical pulping, 21 20-21 Mechanical pulps, in papermaking, 18 93-94... 

Lee, D.Y. and Sumimoto, M., "Mechanochemistry of Lignin. V. An Intensive Chromophore in Mechanical Pulps Bleached With Alkaline Hydrogen Peroxide", Hokforschmg, 1991, 45 (Supplement), 15. 

This article is organized first to examine the issues associated with pulp mill raw materials. It then focuses on chemical pulping, mechanical pulping, bleaching, and papermaking. It is designed to overview the major technical concerns associated with these technologies. 

Given the general properties of wood furnish as identified above, it is now important to examine specific chemical and mechanical pulping, bleaching, and papermaking technologies. 

Peroxide Beeaching Chemistry Mechanical Pulp Bleaching... 

Several aspects of aqueous hydrogen peroxide chemistry are relevant to chemical and mechanical pulp bleaching. 

The reactions of hydroxyl radicals, formed in mechanical pulp bleaching from alkaline peroxide, are entirely undesirable. They represent an unprofitable decomposition of the bleaching agent. 

CW Dence. Chemistry of mechanical pulp bleaching. In CW Dence and DW Reeve, eds. Pulp Bleaching Principles and Practise. Atlanta Tappi Press, 1996, pp. 160-181. 

DY Lee and M Sumimoto. Mechanochemistry of lignin V. An intensive chromophore in mechanical pulps bleached with alkahne hydrogen peroxide. Holzforschune 45 (suppl) 15-20, 1991. 

FIGURE 13.4 Reduction of 6>r /zo-benzoquinoid and coniferaldehyde-type structures during hydrosulfite bleaching. (Adapted from Dence, C.W., In Chemistry of Mechanical Pulp Bleaching in Pulp Bleaching Principles and Practice, Tappi Press, Atlanta, Georgia, 161-182, 1996.)... 

Mechanical Pulping (Bleached) Coarse Solids Separation +Grit Removal + Neutralization ... 

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