Patent ID: 6273994
Filing Date: 2001-08-14
Classification: D21C,Y10S

Abstract:
A method for determining the bleach requirement and bleachability of pulp, said method comprising:i) providing a pulp sample obtained from a pulp stock into an off-line reaction chamber;ii) controlling the amount of the pulp sample in the off-line reaction chamber;iii) conducting one or more first optical measurement of the pulp sample;iv) adding at least one chemical to the pulp sample in the off-line reaction chamber in a controlled manner by:a) adding at least one compound to create a bleaching medium;b) deactivating the bleaching medium by adding at least one alkaline compound, and maintaining the bleaching medium at an alkaline pH level in the reaction chamber;c) reactivating the bleaching medium by adding at least one acid compound, and maintaining the bleaching medium at an acidic pH level in the reaction chamber;v) conducting one or more second optical measurement;vi) processing the first, second, or both the first and the second optical measurement to determine the bleach requirement and bleachability of the pulp sample; andvii) from said bleach requirement and bleachability determined in step vi) extrapolating an amount of chemical required to fully bleach the pulp stock, said method carried out prior to adding bleach to the pulp stock, and said method conducted in less than about 60 min.