METHOD OF EFFECTING FLOCCULATION AND POLYMERIC FLOCCULANT COMPOSITION

摘要

1462946 Acrylamide polymer flocculant compositions SUMITOMO CHEMICAL CO Ltd 8 May 1974 [9 May 1973] 20357/74 Heading C1C Also in Division C3] A method for flocculating particulate material in waste water comprises adding to the water 0À1-10 p.p.m. of a composition which comprises 90-99 parts by weight of a polymer containing at least 50 mole per cent of acrylamide units, and at least 1 but less than 10 parts by weight of one or more precondensates of formaldehyde with urea, melamine, guanidine or dicyandiamide. The acrylamide polymer may be a homopolymer, a cationically modified homopolymer or a nonionic, anionic or cationic copolymer, e.g. with such comonomer components as acrylonitrile, methacrylamide, styrene, an acrylic acid, vinyl sulphonic or itaconic acid salt, dialkylamino ethyl acrylate or vinyl pyridine. The precondensate may contain methoxymethyl groups. The composition may be added as a dry powder or as a 0À1-1% by weight aqueous solution. The method is useful for removing suspended particles, for improving the dewatering and filtration of flocculated sludge, and sometimes for improving decoloration. Examples illustrate the flocculation of slurries of diatomaceous earth and kaolin.