Peroxide - Activated Peroxide - Perborate Which One to Use and Where to Add it in the Bleaching of Mechanical Pulp", 1997 Pulping Conference Proceedings

It is well known from the literature that the use of hydrogen peroxide in the pulp and paper industry can improve certain pulp characteristics such as brightness and certain strength values. However, Canadian mills is forced to seek new options to remain competitive in the actual market. In this work, besides hydrogen peroxide we also evaluate the efficiency of two other chemical agents: activated peroxide and sodium perborate. We investigate two alternatives for the addition of each oxidizing agents. The first one is an application in a conventional bleaching tower. The second one is an addition in the eye of the refiner.

It is well known from the literature that the use of hydrogen peroxide in the pulp and paper industry can improve certain pulp characteristics such as brightness and certain strength values. However, Canadian mills is forced to seek new options to remain competitive in the actual market. In this work, besides hydrogen peroxide we also evaluate the efficiency of two other chemical agents: activated peroxide and sodium perborate. We investigate two alternatives for the addition of each oxidizing agents. The first one is an application in a conventional bleaching tower. The second one is an addition in the eye of the refiner.

The results of the second part of the study demonstrate that sodium perborate is a more powerful bleaching agent than peroxide if used in the eye of the refiner; at equivalent oxidizing charge, up to 14 points ISO were gained for the peroxide and up to 20 points ISO were gained for perborate. Most of the strength properties have been improved. The use of sodium perborate in the refiner represents an alternative which could be more economical than peroxide.