Recycling deinking

Stawicki B, Read B (Hrsg.) (2010) The future of paper recycling in Europe opportunities and limitations. Final report of the COST action E48. Chapter 2.6.3 Recycling Deinking Lines, PITA, Greater Manchester... 

Deinking is the process by which the ink is removed from paper to allow it to be recycled. Deinking is carried out on low cost paper such as newsprint as well as fine paper, but cellulase is playing a role only in fine paper deinking at this time. 

Waste paper has become one of the most important raw materials for the production of paper and cardboard [1]. Besides simple repulping, deinking has become the best known technique for waste paper recycling. Deinked stock is the predominant raw material in the manufacture of newsprint, recycled graphic paper and sanitary paper in Central Europe, and its use in wood-containing paper for magazines is likely to become possible within the near future [2]. 

Inorganic chemicals may also be used. Beatonite may be used as a flocculant ia combination with polymer treatmeat. Alum, oace a common coagulant, is less used because its concentration can build up ia recycle water. Alum oftea biads ink to fibers and iacreases the difficulty of deinking. Removal of the very small flexographic ink particles ia process water is difficult. Ultrafiltratioa (qv) has beea proposed for removing these very small dispersed ink particles (53). 

Contaminant removal processes depend on the type and source of secondary fiber to be pulped. Mill paper waste can be easily repulped with minimal contaminant removal. Recycled postconsumer newspaper, on the other hand, may require extensive contaminant removal, including deinking, prior to reuse. Secondary fiber is typically used in lower-quality applications such as multiply paper-board or corrugating paper. 

Schwarz M (2000) Design of recycled fiber processes for different paper and board grades. In Gottsching L, Pakarinen H (eds) Recyled fiber and Deinking. Fapet Oy, Helsinki (Chap. 6)... 

This has historically involved only minimal use of chemical additives. The product is usually unsized and, because of its low cost, the use of polyelectrolytes for retention is not usually cost-effective. However, this situation is changing as a result of the trend towards limited filler inclusion and also the increased use of deinked waste paper. Newsprint is usually made in an acidic system due to the naturally low pH of groundwood pulp but, as more recycled fibre is used, the process may eventually become neutral. 

Lassus, A. (2000), in Recycled Fiber and Deinking, Book 7, Gottsching, L., ed., Gummerus Printing, Jyvaskyla, Finland, pp. 241-264. 

Papeterie du Rhin, Paper Roll Mill, France. In 1999, Veolia Water STI installed an MBR with Zeeweed ultrafiltration membranes (pore size 0.04 p.m) in Papeterie du Rhin s paper roll mill in France (Table 35.1). Recycled (not deinked) paper is used as the raw material. The bioreactor (1500 m ) is operated at a mixed liquor suspended solids (MLSS) content of 12-16 g/L. Brockmann and Praderie [58] report an average flux of 15 L/(m h) at a pressure of 0.15 bar over a 1 year filtration period. The wastewater from the mill is first prescreened with dmm screens, then sent to an equalization basin, from which it is pumped directly into the bioreactor. Table 35.6 summarizes the performance of the MBR process. The pressure used to draw the water through the membrane is 7-55 kPa. The filtrate is partly recycled as process water [27,57,58]. 

Chabot B, Krishnagopalan GA, and Abubakr S. Effect of ultrafiltration permeate recycling on deinking efficiency of flexo-printed newspapers. Progr. Pap. Recycl. 1998 August 28-38. 

New applications are the utilization of sodium silicate solutions in deinking (decolorization) processes in the paper industry in paper recycling to increase the efficiency of the bleaching agent H2O2 and in secondary oil recovery. 

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