Bleaches recent technologies

McDonough, T. J., Recent Advances in Bleached Chemical Pulp Manufacturing Technology, Part 1 Extended Delignification, Oxygen Delignification, Enzyme Applications, and ECF and TCF Bleaching, Tappi J., 78(3) 55 (1995)... 

Eastman Kodak discovered that HABI technology was of value in bleaching out of sensitizing dyes. Patents continued to issue for over 30 years in this area. The first were U.S. Patents 4,196,002 and 4,201,590 this interest has continued. As recently as 2003, there were bleach-out patents from Eastman Kodak. 

A number of experimental chemical wood bleaching technologies have recently been disclosed hydrogen peroxide and tetraacetyl ethylene diamine,240 anthracene derivatives with hydrogen peroxide241 and in situ produced performic acid242 are but a few. 

The relative merits of TCF and ECF bleaching have been vigorously debated in recent years. These developments are now increasingly seen as a step in the evolution towards Totally Effluent Free (TEF) processes, which aim to prevent all emissions from bleach plants. It is currently believed that mill closure could be achieved with TCF and ECF bleaching technologies, but in practice the former is likely to be cheaper and easier to implement [352]. 

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