Nippon Paper Industries Co., Ltd.

Aikawa Iron Works Co., Ltd.

Tatsumi Hosaka

Yoshihiko Aikawa

Shisei Goto

Takaharu Noda

Tomoaki Koyanagi

Hiroki Ohtake

Minoru Ishida

Masami Kashibo

Munetaka Sonoda

The purpose of the present invention is to provide technology for regenerating pulp having high quality with compact pulp regenerating equipment and less energy. In the pulp regenerating method of the present invention, pulp slurry containing 1.5 wt % or more of a solid component including waste paper pulp is separated into a long fiber fraction and a short fiber fraction by using an outward type slit screen including an opening portion having a slit width in the range of 0.1 mm to 0.3 mm. The solid component ratio of the long fiber fraction and the short fiber fraction is in the range from 10:90 to 60:40, and the difference in Canadian Standard Freeness of the long fiber fraction and the short fiber fraction is in the range of 100 ml to 300 ml.

Processes for preparing pulp and paper

A flotation apparatus F includes a tankfor receiving a liquid raw material, and introduces air into the tankto generate bubbles for adsorbing print ink in the liquid raw material to the bubbles, thereby floating and separating the print ink. The flotation apparatus F includes a circulating device for circulating the liquid raw material by raising and then lowering the liquid raw material in the tank, an air supply tubefor supplying air into the tank, and an agitating memberprovided in the tankfor taking the air from the air supply tubeand agitating the air for forming the air into fine bubbles. The agitating memberhas a rotary shaftheld horizontally and a plurality of membershorizontally separately provided around an outer periphery. On a cross section transverse to a longitudinal direction of the tank, an outer periphery of the agitating memberis arranged on a lower side of the tankand in a position at a downstream side of the liquid raw material relative to a vertical line V passing through a center of the tank

Flotation apparatus

Growing community of inventors

Hokkaido, Japan

Tatsumi Hosaka