Ebara Corporation

Research Association of Pulp and Paper Technology

Keiji Hasegawa

Hiroshi Nagai

Takashi Kawakami

Takanobu Sugo

Kunio Fujiwara

Shuichi Nagato

Hideo Kawazu

Kazuyoshi Takeda

Noriaki Seko

Akio Katakai

Masaji Akahori

Junichi Kanno

Satoshi Konishi

Akira Shimokura

Kazushige Tanae

Tokiya Yaguchi

Shin Hasegawa

Hideyuki Misawa

An object of the present invention is to provide a structure of a metal collecting material for use in seawater or river water or industrial wastewater to give the most excellent adsorption efficiency. Another object of the present invention is to provide a process for efficiently separating and recovering valuable metals or noxious metals from a metal collecting material having collected said valuable metals from seawater or noxious metals from river water or wastewater with the least possible waste generation. A metal collector according to an aspect of the present invention is formed by stacking at least partially alternate layers of a fibrous metal collecting material with a spacer for introducing a liquid to be treated into said collecting material, wherein the area of spacer side faces represents 25-75% of the total area of collecting material side faces and spacer side faces in the side faces of the stack. A process for eluting and recovering a metal from a metal collecting material according to another aspect of the present invention comprises the steps: (1) contacting the metal collecting material having absorbed a metal with a dilute eluent, (2) contacting the metal collecting material with an eluent more concentrated than in step 1 to recover the metal into the eluent; and (3) contacting a metal resorbing material with the eluate from step 2 to resorb the metal.

Metal-collecting apparatus and method for elution and recovery of metal from metal-collecting material

A method and apparatus are disclosed for concentrating an alkaline waste liquor containing sulfur compounds, the so-called black liquor, which is discharged from a step of Kraft-cooking wood fibers, in order to recover the cooking chemicals from said waste liquor, characterized in that CO.sub.2 gas and/or a gas containing CO.sub.2 gas is added to said waste liquor as a boiling-point-lowering agent, viscosity-lowering agent and solidification promoter, after a step of oxidizing said waste liquor and in or prior to one or more stages during the step of concentrating said waste liquor. Also disclosed is an apparatus for concentrating an alkaline waste liquor containing substantially no sulfur compounds (i.e., an AP black liquor), comprising (1) a primary concentrator for concentrating the AP black liquor discharged from said cooking means and washing means, (2) a secondary concentrator for further concentrating the AP black liquor concentrated in said primary concentrator and (3) exhaust gas absorbing means disposed between said primary and secondary concentrators.

Method for concentrating black liquor with oxidizing followed by

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Kanagawa, Japan

Keiji Hasegawa