Nippon Paper Industries Co., Ltd.

Hiromichi Tsuji

Shisei Goto

Keigo Watanabe

Takeshi Iimori

Takanori Miyanishi

The first invention aims to provide a method for preparing stiffer bulky pulp at a freeness level comparable to that obtained by mechanical treatments to improve the bulkiness of product paper by searching for a method capable of adjusting freeness while suppressing damage to pulp fibers and internal fibrillation in a process for producing pulp. The second invention aims to strip contaminants deposited on pulp fibers and/or inorganic particles to reduce adhesion of the contaminants and decrease microorganisms in a treatment of process water containing long pulp fiber fractions used in a process for producing pulp and paper, thereby clarifying process water and thus preparing high-quality pulp and paper. According to the first invention, cavitation is generated in a pulp suspension preferably by a liquid jet and the resulting fine bubbles are introduced into the pulp suspension to adjust the pulp suspension to a desired freeness by means of the impact force induced by collapse of the fine bubbles in a process for producing pulp. According to the second invention, process water containing 50% by weight or less, based on total solids, of long pulp fiber fractions used in a process for producing pulp and/or paper is treated by cavitation generated by a liquid jet and then returned to the process for producing pulp and/or paper and reused.

Methods for beating pulp, methods for treating process waters, and methods for producing pulp and paper

Pulp processing equipment used to produce high-quality recycled pulp with little damage to fibers, high brightness and low residual ink by means of a force selectively acting on fiber surfaces during the process of recycling waste paper is disclosed. Moreover, fiber surfaces are modified by means of a force acting on only the fiber surfaces to obtain high-quality pulp and to render harmless dirts deteriorating pulp quality. A jet system is provided having one or more nozzles for jetting an aqueous slurry containing a material comprising cellulose into a vessel.

Methods for producing recycled pulp, methods for modifying pulp fiber surfaces and dirts, as well as pulp processing equipments

The present invention aims to produce high-quality recycled pulp with little damage to fibers, high brightness and low residual ink by means of a force selectively acting on fiber surfaces during the process of recycling waste paper. Moreover, fiber surfaces are modified by means of a force acting on only the fiber surfaces to obtain high-quality pulp and to render harmless dirts deteriorating pulp quality. A method for producing recycled pulp characterized in that cavitation is generated and used to strip contaminants deposited on fibers and ash during the process of recycling waste paper. Contaminants such as ink deposited on fibers and ash are stripped/fragmented by means of the impact force induced by collapse of fine bubbles by actively introducing bubbles generated by cavitation into a pulp suspension. A jet system having one or more nozzles for jetting an aqueous slurry containing a material comprising cellulose into a vessel.

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Tokyo, Japan

Hiromichi Tsuji