Process for clarifying aqueous suspensions of particulate solids

Claim 1

A method for clarifying an aqueous suspension of finely divided solids, said suspension being selected from the group consisting of (1) coal wash water (2) coal concentrate (3) iron ore slime (4) raw water and (5) raw sewage, comprising treating said suspension with a polymeric flocculat-ing agent and an aqueous acid colloidal solution of a melamine /formaldehyde resin containing from 2 to about 12 moles of formaldehyde per mole of melamine; provided that: (I) in treating said suspension (1), the polymeric flocculating agent is selected from the group consisting of an anionic partially hydrolyzed polyacrylamide, an anionic par-tially hydrolyzed polyacrylonitrile and an anionic copolymer of acrylamide and acrylic acid or its salts; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 4 to about 12 moles of formaldehyde per mole of melamine; (II) in treating said suspension (2), the polymeric flocculating agent is selected from the group consisting of an anionic partially hydrolyzed polyacrylonitrile, an anionic par-tially hydrolyzed polyacrylamide, an anionic copolymer of ac-rylamide and acrylic acid or its salts and a non-ionic poly-acrylamide containing less than 1% carboxyl groups; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 4 to about 12 moles of formaldehyde per mole of melamine; (III) in treating said suspension (3), the polymeric flocculating agent is selected from the group consisting of a cationic polydiallyldimethylammonium chloride, a cationic amine/epichlorohydrin polymer, cationic polyacrylamides, cat-ionic alkylene polyamines and a non-ionic polyacrylamide con-taining less than 1% carboxyl groups; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 4 to about 12 moles of formaldehyde per mole of melamine; (IV) in treating said suspension (4), the polymeric flocculating agent is selected from the group consisting of a cationic amine/epichlorohydrin polymer, a cationic aminoalkyl-ated polyacrylamide, an alkylene polyamine polymer and a cat-ionic acrylamide/vinylamine copolymer; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 2 to about 12 moles of formaldehyde per mole of melamine; (V) in treating said suspension (5), the polymeric flocculating agent is a cationic aminoalkylated polyacrylamide, a cationic amine/epichlorohydrin polymer, a cationic acryl-amide/vinylamine copolymer or a cationic alkylene polyamine; and the aqueous acid colloidal solution of melamine/formalde-hyde resin contains from 2 to about 12 moles of formaldehyde per mole of melamine.

Claim 2

A method for clarifying an aqueous suspension of finely divided solids, said suspension being selected from the group consisting of (1) coal wash water (2) coal concentrate (3) iron ore slime (4) raw water and (5) raw sewage, comprising treating said suspension with a polymeric flocculat-ing agent and an aqueous acid colloidal solution of a melamine /formaldehyde resin containing from 2 to about 12 moles of formaldehyde per mole of melamine; provided that: (I) in treating said suspension (1), the polymeric flocculating agent is selected from the group consisting of an anionic partially hydrolyzed polyacrylamide, an anionic par-tially hydrolyzed polyacrylonitrile and an anionic copolymer of acrylamide and acrylic acid or its salts; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 4 to about 12 moles of formaldehyde per mole of melamine; (II) in treating said suspension (2), the polymeric flocculating agent is selected from the group consisting of an anionic partially hydrolyzed polyacrylonitrile, an anionic par-tially hydrolyzed polyacrylamide, an anionic copolymer of ac-rylamide and acrylic acid or its salts and a non-ionic poly-acrylamide containing less than 1% carboxyl groups; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 4 to about 12 moles of formaldehyde per mole of melamine; (III) in treating said suspension (3), the polymeric flocculating agent is selected from the group consisting of a cationic polydiallyldimethylammonium chloride, a cationic amine/epichlorohydrin polymer, cationic polyacrylamides, cat-ionic alkylene polyamines and a non-ionic polyacrylamide con-taining less than 1% carboxyl groups; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 4 to about 12 moles of formaldehyde per mole of melamine; (IV) in treating said suspension (4), the polymeric flocculating agent is selected from the group consisting of a cationic amine/epichlorohydrin polymer, a cationic aminoalkyl-ated polyacrylamide, an alkylene polyamine polymer and a cat-ionic acrylamide/vinylamine copolymer; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 2 to about 12 moles of formaldehyde per mole of melamine; (V) in treating said suspension (5), the polymeric flocculating agent is a cationic aminoalkylated polyacrylamide, a cationic amine/epichlorohydrin polymer, a cationic acryl-amide/vinylamine copolymer or a cationic alkylene polyamine; and the aqueous acid colloidal solution of melamine/formalde-hyde resin contains from 2 to about 12 moles of formaldehyde per mole of melamine.

Claim 3

A method for clarifying an aqueous suspension of a coal wash water comprising treating said coal wash water with a polymeric flocculating agent and an aqueous acid colloidal solution of a melamine/formaldehyde resin containing from 2 to about 12 moles of formaldehyde per mole of melamine; provided that: in treating said coal wash water the polymeric flocculating agent is selected from the group consisting of an anionio partially hydrolyzed polyacrylamide, an anionic par-tially hydrolyzed polyacrylonitrile and an anionic copolymer of aarylamide and acrylic acid or its salts; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 4 to about 12 moles of formaldehyde per mole of melamine.

Claim 4

A method for clarifying an aqueous suspension of a coal wash water comprising treating said coal wash water with a polymeric flocculating agent and an aqueous acid colloidal solution of a melamine/formaldehyde resin containing from 2 to about 12 moles of formaldehyde per mole of melamine; provided that: in treating said coal wash water the polymeric flocculating agent is selected from the group consisting of an anionio partially hydrolyzed polyacrylamide, an anionic par-tially hydrolyzed polyacrylonitrile and an anionic copolymer of aarylamide and acrylic acid or its salts; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 4 to about 12 moles of formaldehyde per mole of melamine.

Claim 5

A method for clarifying an aqueous suspension of a coal concentrate comprising treating said suspension with a polymeric flocculating agent and an aqueous acid colloidal so-lution of a melamine/formaldehyde resin containing from 2 to about 12 moles of formaldehyde per mole of melamine; provided that: in treating said suspension the polymeric floccula-ting agent is selected from the group consisting of an anionic partially hydrolyzed polyacrylonitrile, an anionic partially hydrolyzed polyacrylamide, an anionic copolymer of acrylamide and acrylic acid or its salts and a non-ionic polyacrylamide containing less than 1% carboxyl groups; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 4 to about 12 moles of formaldehyde per mole of melamine.

Claim 6

A method for clarifying an aqueous suspension of a coal concentrate comprising treating said suspension with a polymeric flocculating agent and an aqueous acid colloidal so-lution of a melamine/formaldehyde resin containing from 2 to about 12 moles of formaldehyde per mole of melamine; provided that: in treating said suspension the polymeric floccula-ting agent is selected from the group consisting of an anionic partially hydrolyzed polyacrylonitrile, an anionic partially hydrolyzed polyacrylamide, an anionic copolymer of acrylamide and acrylic acid or its salts and a non-ionic polyacrylamide containing less than 1% carboxyl groups; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 4 to about 12 moles of formaldehyde per mole of melamine.

Claim 7

A method for clarifying an aqueous suspension of an iron ore slime comprising treating said suspension with a poly-meric flocculating agent and an agueous acid colloidal solution of a melamine/formaldehyde resin containing from 2 to about 12 moles of formaldehyde per mole of melamine; provided that: in treating said suspension the polymeric floccula-ting agent is selected from the group consisting of a cationic polydiallyldimethylammonium chloride, a cationic amine/epichlo-rohydrin polymer, cationic polyacrylamides, cationic alkylene polyamineq and a non-ionic polyacrylamide containing less than 1% carboxyl groups; and the aqueous acid colloidal solu-tion of melamine/formaldehyde resin contains from 4 to about 12 moleq of formaldehyde per mole of melamine.

Claim 8

A method for clarifying an aqueous suspension of an iron ore slime comprising treating said suspension with a poly-meric flocculating agent and an agueous acid colloidal solution of a melamine/formaldehyde resin containing from 2 to about 12 moles of formaldehyde per mole of melamine; provided that: in treating said suspension the polymeric floccula-ting agent is selected from the group consisting of a cationic polydiallyldimethylammonium chloride, a cationic amine/epichlo-rohydrin polymer, cationic polyacrylamides, cationic alkylene polyamineq and a non-ionic polyacrylamide containing less than 1% carboxyl groups; and the aqueous acid colloidal solu-tion of melamine/formaldehyde resin contains from 4 to about 12 moleq of formaldehyde per mole of melamine.

Claim 9

A method for clarifying an aqueous suspension of a raw water comprising treating said suspension with a polymeric flocculating agent and an aqueous acid colloidal solution of a melamine/formaldehyde resin containing from 2 to about 12 moles of formaltehyde per mole of melamine; provided that: in treating sald suspension, the polymeric floccu-lating agent is selected from the group consisting of a cationic amine/epichlorohydrin polymer, a cationic aminoalkylated poly-acrylamide, an alkylene polyamine polymer and a cationic acryl-amide/vinylamine copolymer; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 2 to about 12 moles of formaldehyde per mole of melamine.

Claim 10

A method for clarifying an aqueous suspension of a raw water comprising treating said suspension with a polymeric flocculating agent and an aqueous acid colloidal solution of a melamine/formaldehyde resin containing from 2 to about 12 moles of formaltehyde per mole of melamine; provided that: in treating sald suspension, the polymeric floccu-lating agent is selected from the group consisting of a cationic amine/epichlorohydrin polymer, a cationic aminoalkylated poly-acrylamide, an alkylene polyamine polymer and a cationic acryl-amide/vinylamine copolymer; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 2 to about 12 moles of formaldehyde per mole of melamine.

Claim 11

A method for clarifying an aqueous suspension of a raw sewage, comprising treating said suspension with a polymeric flocculating agent and an aqueous acid colloidal solution of a melamine/formaldehyde resin containing from 2 to about 12 moles of formaldehyde per mole of melamine; provided that: in treating said suspension, the polymeric floccu-lating agent is a cationic aminoalkylated polyacrylamide, a cationic amine/epichlorohydrin polymer, a cationic acrylamide/-vinylamine copolymer or a cationic alkylene polyamine; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 2 to about 12 moles of formaldehyde per mole of melamine.

Claim 12

A method for clarifying an aqueous suspension of a raw sewage, comprising treating said suspension with a polymeric flocculating agent and an aqueous acid colloidal solution of a melamine/formaldehyde resin containing from 2 to about 12 moles of formaldehyde per mole of melamine; provided that: in treating said suspension, the polymeric floccu-lating agent is a cationic aminoalkylated polyacrylamide, a cationic amine/epichlorohydrin polymer, a cationic acrylamide/-vinylamine copolymer or a cationic alkylene polyamine; and the aqueous acid colloidal solution of melamine/formaldehyde resin contains from 2 to about 12 moles of formaldehyde per mole of melamine.