Myrens Verksted A/s

Nicolai Soteland

Bjorn H Fritzvold

In a method for bleaching oxygen delignified cellulose-containing pulp such as sulphate, sodium and sulphite pulps with ozone and peroxide, the ozone treatment takes place at two stages, the alkaline solution which is added subsequent to the ozone treatment includes peroxide and complex formers, and 55 to 85% of the total amount of chemicals is added at the first stage.

Method for bleaching oxygen delignified cellulose-containing pulp with

When treating refined mechanical pulp and thermo mechanical pulp with ozone, it is of great importance that the process be carried out at the most favorable conditions and with a minimum consumption of energy. According to the present invention the pulp is refined to a freeness value of at least 200 csf in a first stage refiner from which the pulp is passed to a high consistency ozonizer and maturation reactor for a time limited to maximum 30 minutes. From the reactor the pulp is passed direct to a second stage refiner, the pulp then having a solids content of approximately 8-10% and an alkaline value in the range of 7-10.

Growing community of inventors

Oslo, Norway

Nicolai Soteland