Bleaching, pulp

Bleaching is the treatment of wood pulps with chemical agents to increase their optical brightness. Mechanical and chemical pulps undergo different 

Although sodium hydroxide has been the primary alkali used in oxygen deligniflcation of sulfite pulps, its replacement by magnesium hydroxide 

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Most of the chlorine produced is used in the manufacture of chlorinated compounds for sanitation, pulp bleaching, disinfectants, and textile processing. Further use is in the manufacture of chlorates, chloroform, carbon tetrachloride, and in the extraction of bromine. 

Pulp and paper Pulp and paper industry Pulp and paper mills Pulp bleaching... 

Uses. The principal uses of NaBH are ia synthesis of pharmaceuticals (qv) and fine organic chemicals removal of trace impurities from bulk organic chemicals wood-pulp bleaching, clay leaching, and vat-dye reductions and removal and recovery of trace metals from plant effluents. 

Bleaching. The largest single use for hydrogen peroxide in the United States and North America is wood pulp bleaching, but consumption for the manufacture of chemicals, environmental appHcations, and for bleaching cotton (qv), wool (qv), and other textiles (qv) is significant. 

International Non-Chlorine Bleaching Conference, Amelia Island, Ela., Mar. 1994 and 1995 International Pulp Bleaching Conference, Vancouver, B.C.,June 1994. 

R. H. Voss, C. E. Luthe, B. 1. Deming, R. M. Berry and L. H. AHen, "Some New Insights into the Origins of Dioxins Formed During Chemical Pulp Bleaching," paper presented at the CPPA Environment Conference 1988, Vancouver, B.C., Canada, Oct. 25—26,1988. 

Caro s acid is finding increasing appHcation ia hydrometaHurgy, pulp bleaching, effluent treatment, and electronics. There are several appHcations of Caro s acid ia hydrometaHurgy. It is usually made on-site by either the isothermal or the adiabatic process. The latter method is preferred because its capital cost is less and the system is safer due to the fact that the product is used as soon as it is made. 

Fig. 29. CEDED pulp bleaching sequence A, delignifying, and B, brightening stages.

T. J. McDonough, Kraft Pulp Bleaching Technology A Brief Overview of Basic Principles and Current Trends, Institute of Paper Chemistry, Adanta, Ga., 1992. 

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