Title
Bleaching of softwood kraft pulp with oxygen and peroxide
Authors
DAN GAVRILESCU and ADRIAN CATALIN PUITEL

Received January 15, 2013
Published Volume 49 Issue 3-4 March-April
Keywords pulp bleaching, oxygen, hydrogen peroxide

Abstract
The bleaching of spruce kraft pulp with oxygen and peroxide according to the (OP)-Q-(EOP)-P sequence is investigated. Pulp brightness and properties highly depend on unbleached pulp Kappa number and on the residual lignin content after the EOP stage. At the same time, the final P stage conditions strongly influence the bleaching results. In order to achieve satisfactory pulp brightness, it is necessary to split the chemical charge in the P stage, so that the peroxide is added in two or three consecutive steps. The successive addition of peroxide significantly improves pulp brightness in the P stage.