A method for manufacturing mechanical pulp

• Main Authors: LEHTO JOUKO, OERSAA FOLKE, KOCIMSKI SERGE, GUMMERUS MARKKU, HAERKOENEN ESKO, PIRINEN LIISA, TIENVIERI TAISTO, PIIRAINEN MIA
• Format: Patent
• Language: Chinese; English
• Published: 18.03.2009
• Subjects: APPARATUS THEREFOR; FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT; PAPER-MAKING; PRODUCTION OF CELLULOSE; PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCESFROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; TEXTILES

The present invention relates to a method for manufacturing mechanical pulp, the method comprising: introducing raw material of the mechanical pulp, refining the raw material in a first refining stage in order to form the mechanical pulp, adjusting the pH of the mechanical pulp between 9 and 11 in aprocess step in which a first process delay is arranged, the first process delay being at least 0.5 hours, sorting the mechanical pulp into a first accepted stock (A1) and a first rejected stock (R1), ozonizing the first rejected stock (R1) whose pH at the start of the ozonation process is between 9 and 11, refining the ozonated first rejected stock (R1) in a second refining stage so that at least a part of it will belong to a second accepted stock, and -combining the accepted stocks. The present invention also relates to the use of the mechanical pulp.