Bleaching of pulps

R. P. Singh, ed.. The Bleaching of Pulp, TAPPI monograph series, 3rd ed.. Technical Association of the Pulp and Paper Industry, Adanta, Ga., 1979. 

Dichlorine monoxide is an intermediate in the manufacture of calcium hypochlorite. It has been used in sterilization for space appHcations (70) (see Sterilization techniques). Its use in the preparation of chlorinated solvents (71) and chloroisocyanurates has been described. Chlorine monoxide has been shown to be effective in bleaching of pulp (qv) and textiles (72—74). 

Technical, economic, and environmental advantages exist for ozone bleaching of pulp in the paper industry as an alternate to hypochlorite or chlorine bleaching which yields deleterious compounds to the environment. 

Chlorine bleaching of pulp Water BOD, color, chlorinated organics, resin acids... 

Bright DA, McKague B, Hodson PV, et al. 1998. Use of chlorine dioxide for the bleaching of pulp a re-evaluation of ecological risks based on scientific progress since 1993. International Environmental Conference Exhibit Bk 3 1051-1054. 

Dillner B, Larsson LO, Tibbling P. 1990. Nonchlorine bleaching of pulp produced by the modified continuous cooking process. TAPPI 73(8) 167-172. 

Sodium hypochlorite is the primary hypochlorite used as a bleach and disinfectant, accounting for 83% of world hypochlorite use, with calcium hypochlorite accounting for the remaining 17%. Approximately 1 million tons of sodium hypochlorite was used globally in 2005, with about half this amount used in households for laundry bleaching and disinfection. The other half was used primarily for wastewater and drinking water treatment other uses include pool sanitation, bleaching of pulp, paper, and textiles, and as an industrial chemical. 

Enzymes in the Pulp and Paper Industry Bleaching of Pulp with Xylanases or Laccases 145... 

In practice, the bleaching of pulp is accomplished in successive stages, each of them characterized by appropriate chemicals and conditions. The bleaching procedure is chosen with respect to the pulp type in order to attain target brightness with preservation of strength properties (Table 8-1). In recent years increasing attention has been directed toward improvement of the... 

It also keeps the pH buffered in the alkaline range required for the peroxide bleaching of pulp. Sodium silicate has also become an important ingredient of the chemical formulation for the de-inking of printed waste paper. 

Nelson, P., Elemental Chlorine Free (ECF) and Totally Chlorine Free (TCF) Bleaching of Pulps, in Environmentally Friendly Technologies for the Pulp and Paper Industry, R. A. Young and M. Akhtar (Eds.), John Wiley Sons, New York, 1998. 

Rapson, W. H., Ed. The Bleaching of Pulp, Tappi Monograph Series... 

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