Effect of the final ECF bleaching stage on Eucalyptus Kraft pulp properties : a comparison between hydrogen peroxide and chlorine dioxide

The factors contributing to the differences between chlorine dioxide and hydrogen peroxide final ECF bleaching stages are discussed with respect to the properties of Eucalyptus globulus kraft pulps. The higher beatability of pulps bleached with a final peroxide stage was assigned to the better fibre swelling capacity. For laboratory beaten fibres, dry zero-span tensile strength is a more suitable predictor of fibre strength than wet zero-span or intrinsic viscosity, at least when comparing pulps with different bleaching history. A comparison between laboratory and industrial bleached pulps is also provided