METHOD OF PROVIDING A PAPER FIBRE COMPOSITION

The present invention relates to a method of production of a paper fibre composition， comprising the steps of: a) Providing a vessel， b) Providing Na 2S03 in the range of 12-122 kg/bdt combined with NaOH in the range of 0-97 kg/bdt， or NaHSO3 in the range of 10-100 kg/bdt combined with NaOH in the range of 10-100 kg/bdt to said vessel， c) Providing wood， preferably softwood chips to said vessel for pre-treatment， d) Providing heat and pressure to said vessel in order be able control the vessel to have a temperature T comprised in the range of 160° C.-184° C.， e) Controlling the retention time t for the wood chips， in relation to the temperature T of the content of the vessel， wherein T is controlled to be within the range of step d) and t is controlled to be in the range of 2-27 min， preferably in the range of 2-25 min， more preferred in the range of 5-20 min， f) Providing a defibration device coupled to the outlet of said vessel， the defibriation device being a refiner， mill， defibrator， fiberizer， or the like， g) Providing the pre-treated wood chips to the defibration device， h) Providing an energy consumption of 75-1000 kWh/bdt in said defibration device. The invention also relates to a paper fibre composition prepared by the method and a paper or paperboard or molded pulp made from the paper fibre composition.