Studies of Alternate Bleaching Sequences for Sulfite Mills, 1995 Pulping Conference Proceedings

Nils G. Johansson, David E. Fletcher,

Dwane S. Hutto, Christian Blom, and

Billy Biggers

Eka Nobel Inc.

David E. Fletcher

Under the EPA’s proposed Cluster Rule program, it has been proposed that the Best Available Technology (BAT) is to be TCF for Papergrade Sulfite. This report addresses the applicability of the Lignox ® O P sequence as a bleaching alternative. In the Kraft process, TCF bleaching sequences have been used with limited success due to brightness ceiling limits, strength loss, and increased chemical costs. However, TCF is well suited for the Sulfite process since brightness can be developed more readily than in the Kraft process. A number of bleaching studies have now been carried out throughout North America and Europe. The results have shown that Sulfite pulps can be effectively bleached with Oxygen and Peroxo compounds. With today’s escalating caustic and chlorine prices, hydrogen peroxide can be used with little or no economic impact.