【発明の名称】アルカリパルプ廃液から苛性ソ-ダを回収する方法

Japanese Patent JPH0784716

B2

Sodium hydroxide is recovered from an alkaline waste liquor ("black liquor") containing substantially no sulfur compounds discharged from a process comprising soda cooking wood fibers, washing and optionally bleaching them, by a direct causticization process. This process comprises: (a) adding a gas comprising carbon dioxide to the black liquor as it is or after concentration to adjust the pH of the black liquor to 9.5 to 12.5 (determined at a black liquor solids concentration of 40% and 80 DEG C), (b) concentrating the above described black liquor to a solids concentration of 50 to 95%, (c) adding the above described carbon dioxide-treated and concentrated black liquor, oxygen and iron oxide to a combustion furnace, subjecting the mixture to combustion and thus burning organic substances and converting inorganic soda components into sodium carbonate and sodium carbonate into sodium ferrite, and (d) hydrolyzing the thus resulting product to recover sodium hydroxide and recycling the recovered iron oxide to step (c). r

Masao Okano
Michihiro Nara
Tatsuo Nakano
Haruka Tsukamoto
Kei Hasegawa
Shuichi Eito
Kamo Tanae
Tokiya Yaguchi
Ito Hayami
Chiaki Nagai
Yukichi Takeshita
Ogawa Katsuyoshi
Kikuoka Kazuma
Koji Iwahashi
Tokunaga Kikuo
Machida Osamu

JP20388686A

September 13, 1995

September 01, 1986

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MITSUBISHI HEAVY INDUSTRIES,LTD.
Shin Oji Paper Co., Ltd.
NIPPON PAPER INDUSTRIES CO.,LTD.
Honshu Paper Co., Ltd.
Ebara Corporation
Kawasaki Heavy Industries, Ltd.
Tsukishima Machinery Co., Ltd.
Babkotsu Hitachi Co., Ltd.

D21C11/00; D21C11/10; D21C11/12; D21C11/04; (IPC1-7): D21C11/04; D21C11/10; D21C11/12

JP454401B1
JP4319082B1
JP58500719A

Akira Uchida (2 outside)

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