US 12,410,559 B2
Production method
Johan Magnusson, Frovi (SE)
Assigned to BILLERUDKORSNAS AB, Solna (SE)
Appl. No. 17/440,286
Filed by Billerudkorsnas AB, Solna (SE)
PCT Filed Mar. 20, 2020, PCT No. PCT/EP2020/057896
§ 371(c)(1), (2) Date Sep. 17, 2021,
PCT Pub. No. WO2020/188112, PCT Pub. Date Sep. 24, 2020.
Claims priority of application No. 1950349-9 (SE), filed on Mar. 20, 2019.
Prior Publication US 2022/0154399 A1, May 19, 2022
Int. Cl. D21D 1/26 (2006.01); D21H 11/02 (2006.01); D21H 11/18 (2006.01); D21H 27/30 (2006.01)
CPC D21D 1/26 (2013.01) [D21H 11/02 (2013.01); D21H 11/18 (2013.01); D21H 27/30 (2013.01)] 27 Claims
OG exemplary drawing
 
1. A method of producing a refined pulp, comprising the steps of:
providing a pulp;
subjecting the pulp to a first conical refining step in at least one conical refiner comprising refining plates having a bar width of 0.5-1.5 mm, and a groove width of 1.0-2.0 mm; and
subjecting the pulp from the first conical refining step to a second conical refining step in at least one conical refiner comprising refining plates having a bar width of 0.5-1.5 mm, and a groove width of 0.8-1.6 mm, to obtain the refined pulp;
wherein:
the groove width is greater than the bar width in the first conical refining step,
the groove width of the second conical refining step is smaller than the groove width of
the first conical refining step,
the pulp is bleached hardwood pulp, and
the consistency of the pulp in the first and the second conical refining step is 2-5%.