Miyoshi Yushi Kabushiki Kaisha

Akira Nishimura

Masafumi Moriya

Kazuo Hosoda

Takao Imachi

Atsuyuki Matsumoto

Hiroshi Ogawara

Koji Onoda

A heavy metal can be removed from waste water, in which the metal is contained as ions, by adding to the waste water a metal scavenger together with at least one of sodium monosulfide, sodium polysulfides and sodium hydrogensulfide to form a metal ion containing floc. The resulting floc is then removed from the waste water by filtration. The metal scavenger contains at least one carbodithio group and/or at least one carbodithioate salt group as N-substituents per molecule.

Removal of heavy metals from waste water

A metal scavenger is composed of an addition product of a polyamine and an epihalohydrin. The addition product contains as substituent or substituents at least one carbodithio group and/or at least one carbodithioate salt group introduced therein by substituting the corresponding number of active hydrogen atom or atoms in the addition product. Metals can be scavenged from waste water by adding the metal scavenger together with at least one of sodium monosulfide, sodium polysulfides and sodium hydrogensulfide.

Metal scavenger and metal scavenging process

A process for preparing polyurethane foams excellent in durability, elasticity and dimensional stability is disclosed. An unsaturated polyester is prepared through the reaction of an unsaturated dicarboxylic acid with a polyhydroxy compound having at least three reactive hydrogen atoms. The polyester is homopolymerized or copolymerized with other vinyl monomers to produce a homopolymer or a homocopolymer. The polymer or the copolymer is used either alone or together with the polyol as a polymer-polyol for the preparation of polyurethane foams.

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Asaka, Japan

Akira Nishimura