US 11,753,771 B2
Method of producing filler
Elina Skerfe, Harplinge (SE); and Erik Mattsson, Svärdsjo (SE)
Assigned to Stora Enso OYJ, Helsinki (FI)
Appl. No. 15/562,943
Filed by Stora Enso OYJ, Helsinki (FI)
PCT Filed Mar. 31, 2016, PCT No. PCT/IB2016/051842
§ 371(c)(1), (2) Date Sep. 29, 2017,
PCT Pub. No. WO2016/157122, PCT Pub. Date Oct. 6, 2016.
Claims priority of application No. 1550390-7 (SE), filed on Mar. 31, 2015.
Prior Publication US 2018/0112360 A1, Apr. 26, 2018
Int. Cl. D21H 17/67 (2006.01); D21H 17/20 (2006.01); D21H 17/70 (2006.01); C01F 11/18 (2006.01); D21C 5/02 (2006.01); D21J 1/00 (2006.01); D21H 17/69 (2006.01); C09C 3/04 (2006.01); C09C 1/02 (2006.01)
CPC D21H 17/675 (2013.01) [C01F 11/181 (2013.01); C09C 1/021 (2013.01); C09C 3/04 (2013.01); D21C 5/02 (2013.01); D21H 17/20 (2013.01); D21H 17/67 (2013.01); D21H 17/69 (2013.01); D21H 17/70 (2013.01); D21J 1/00 (2013.01); C01P 2002/80 (2013.01); C01P 2006/60 (2013.01); Y02W 30/64 (2015.05)] 8 Claims
OG exemplary drawing
 
1. A method of producing filler, comprising precipitated calcium carbonate (PCC), said method comprising the steps of,
providing fly ash generated in paper or paper board production, the fly ash comprising calcium oxide;
fractionating said fly ash in at least one step, whereby a first fraction is separated from a second fraction, the first fraction comprising particles that are coarser compared with particles in the second fraction wherein the first fraction has an average particle size greater than 50 μm and less than 100 μm, and the second fraction has an average particle size of 50 μm or less;
grinding said first fraction prior to the step of forming a suspension, wherein said first fraction is ground to exhibit an average particle size of between 10 to 20 μm;
forming the suspension of only the grounded first fraction having the average particle size of between 10 to 20 μm, wherein the calcium oxide of the fly ash forms calcium hydroxide, wherein the suspension of the grounded first fraction further comprise a furnish that includes cellulose fibers; and,
adding carbon dioxide to said suspension of grounded first fraction comprising the furnish to form precipitated calcium carbonate in the presence of the cellulose fibers.