Paper making and fiber liberation – Processes and products – Non-fiber additive
Patent
1994-10-12
1996-09-10
Chin, Peter
Paper making and fiber liberation
Processes and products
Non-fiber additive
1621641, 1621643, 162183, D21H 2110
Patent
active
055542603
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a method and a use of naphthalene sulphonate salt(s), under granulated form or as a condensed or diluted solution, and a solution of polyethylene oxide having a molecular weight varying from 1.times.10.sup.6 to 13.times.10.sup.6, allowing for a mixture comprising lignocellulosic particles and an aqueous medium to significantly improve the retention of particles such as fines and fibres, on a wire screen and the drainage of the aqueous medium.
Advantageously, a particles retention, especially a retention of fines and fibres can be achieved for kraft, sulphite (high and low yield), bisulphite, mechanical, OPCO, BTCMP, TCMP, BCMP, hard wood, such as oak, birch, maple, elm, wild-cherry, soft woods such as conifere trees, and TMP pulps and any mix in any proportion of two or more types of pulp.
Application of the invention maybe in the following means:
filter in any pulp making process;
production sector; treatment process, including krofta, posseidon, sedimentation clarifier, but not limited to these;
2. Description of the Related Art
Up to now, it was known to use polyethylene oxide to improve from a mixture comprising lignocellulosic fines and fibres, and an aqueous medium, a retention of fines and fibres on a wire screen and improve a drainage of the aqueous medium.
SUMMARY OF THE INVENTION
The Applicant has now surprisingly found that a method involving a combined use of one or several naphthalene sulphonate salt(s), under granulated form or advantageously as a condensed or diluted solution, and a solution of one or several polyethylene oxide having a molecular weight varying from 1.times.10.sup.6 to 13.times.10.sup.6, in admixture with a mixture of lignocellulosic particles and an aqueous medium, allows to improve a retention of said particles on a wire screen and a drainage of said aqueous medium. This combined use shows a synergistic effect. A condensed naththalene sulphonate salt means a solution saturated with said salt, for example a condensed sodium naphthalene sulphonate salt means an aqueous solution containing about 41-46% of said salt.
More particularly, the invention relates to an improvement in a method for the production of paper and analogous products. This improvement is characterized by the fact that one or several naphthalene sulphonate salt(s), said salt(s) being under granulated form or advantageously as a condensed or diluted solution, and a solution of one or several polyethylene oxide having a molecular weight varying from 1.times.10.sup.6 to 13.times.10.sup.6 are admixed with a mixture comprising lignocellulosic particles such as fines and fibres, and an aqueous medium, being understood that polyethylene oxide is admixed with said mixture when said mixture already contains at least a part of said naphthalene sulphonate salt(s).
The invention also relates to the use of one or several naphthalene sulphonate salt(s), said salt(s) being under granulated form or advantageously as a condensed or diluted solution, and a solution of one or several polyethylene oxide having a molecular weight varying from 1.times.10.sup.6 to 13.times.10.sup.6, in admixture with a mixture comprising lignocellulosic particles, such as fines and fibres, and an aqueous medium, to improve a retention of said particles on a wire screen and a drainage of the aqueous medium.
Advantageously, the naphthalene sulphonate salt(s), especially a sodium naphthalene sulphonate salt, is (are) uniformly dispersed in the mixture before introducing one or several polyethylene oxide. Preferably, sodium naphthalene sulphonate should be applied preferably 30 seconds before the salt(s) get(s) in contact with the polyethylene oxide to thus give enough time to the salt to condition particles, such as fines and fibres.
Preferably, in a pulp and paper plant, the admixture of naphthalene sulphonate salt(s) with a mixture of lignocellulosic fines and fibres and aqueous medium may be applied anywhere in the system and advantageously not between fan pumps
REFERENCES:
patent: 4070236 (1978-01-01), Carrard et al.
patent: 4188446 (1980-02-01), Friedman
patent: 4313790 (1982-02-01), Pelton et al.
Database WPIL, Derwent Publication, Ltd., London, GB, CA, A, 2 040 967 (Radu, G.) (Abstract only), Oct., 1992.
Langevin Pierre
Radu Georges
Chin Peter
E.QU.I.P. International Inc.
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