Paper making and fiber liberation – Processes of chemical liberation – recovery or purification... – Chemical treatment after start or completion of mechanical...
Patent
1990-04-09
1992-07-14
Alvo, Steve
Paper making and fiber liberation
Processes of chemical liberation, recovery or purification...
Chemical treatment after start or completion of mechanical...
162 26, 162 28, 162 76, 162 83, 162 86, D21B 116, D21C 910
Patent
active
051299879
ABSTRACT:
A paper pulp refining and bleaching process wherein the pulp is treated in one or more refiners with a sodium hydrosulfite bleach liquor in the presence of a strong alkali such as NaOH, whereby the bleaching solution has an alkaline pH, preferably 10 to 12, and the pulp is discharged from the refiner at a pH of from about 5 to 6. The bleaching produces a brightness gain of at least 8 to 13 ISO points in the refiners. The process is preferably carried out by passing the pulp successively through a primary refiner at elevated pressure, a secondary refiner at atmospheric pressure and a bleaching tower, an alkaline hydrosulfite solution being fed to each.
REFERENCES:
patent: 3388037 (1988-06-01), Asplund et al.
patent: 3467574 (1969-09-01), West
patent: 3804944 (1974-04-01), Kise et al.
patent: 3985674 (1976-10-01), Ellis et al.
patent: 4534954 (1985-08-01), Little et al.
patent: 4676961 (1987-06-01), Appl et al.
patent: 4756799 (1988-07-01), Bengtsson et al.
Meizer et al, paper given to the Wood Pulp Symposium in Munich in 1985.
Search Report U.K. Appl No. 8806206.
Barton et al., Pulp Paper 53, No. 6 pp. 180-181.
Canadian Pulp and Paper Association, 65th Annual Meeting Book "A" Preprints, W. Gandy, pp. A17 and A18 (1979).
1979 Int'l. Mechanical Pulping Conference, J. Lansford, "Rejects Refining and Bleaching of Mechanical Pulp", pp. 323, 324 (1979).
Loras, V., "Brightening of Thermechanical Pulp", Tappi vol. 59, No. 11, pp. 99-101 (Nov. 1976).
Edstrom Bert A.
Joachimides Thomas
Levis Stephen H.
Moldenius Hans B. S.
Alvo Steve
Morton Thiokol Inc.
Rauchfuss, Jr. George W.
White Gerald K.
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