FREMGANGSMAATE FOR FREMSTILLING AV RAFFINOERMASSE FRA TREFILS VED HJELP AV EN MEKANISK-KJEMISK-TERMISK BEHANDLING.

摘要

A process for making a refiner mechanical pulp from wood chips which comprises: (a) Comminuting the wood chips largely by splitting along the wood grain; (b) Wetting said particles with a solution of a sulphite salt of an alkali metal to add an amount of said alkali metal salt within the range of 1% to 10% of the oven dry weight of said particles, said solution having a pH within the range of 7 to 12.5; (c) Steam heating the sulphite salt solution bearing particles to a temperature within the range between 80 DEG C. and 165 DEG C. and holding them within that temperature range for a period of 0.5 to 80 minutes; (d) Passing the particles, after said period of heating, through a disc refiner to produce refiner mechanical pulp.