Method for producing polymer solutions
AssigneeKemira Oyj
InventorsAsko Karppi, Matti Hietaniemi
Life of this patent
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Abstract
A method for producing an aqueous copolymer solution, which comprises dissolving a copolymer of (meth)acrylamide and at least 1 mol-% cationic monomers, calculated from total amount of monomers in the dissolving water having calcium hardness of at least mg/l, expressed as Ca2+, and adding acid comprising monoprotic organic acid and/or mineral acid to the dissolving water and/or the aqueous solution of the copolymer in an amount sufficient to provide the aqueous solution of the copolymer with a pH of equal to or less than 4.5. The invention also relates to uses of the obtained polymer solutions in manufacturing of paper, board or the like or in treatment of sludge or water.
Claims20
A process for flocculating suspended solid particles in manufacturing of a paper, or board, or in treatment of sludge or water, comprising:
- obtaining an aqueous solution of a copolymer by dissolving a copolymer of (meth)acrylamide and at least 1 mol-% cationic monomers, calculated from a total amount of monomers, in dissolving water having a calcium hardness of at least 50 mg/l, expressed as Ca2+ and by adding acid to the dissolving water before and/or after dissolving the copolymer in an amount sufficient to provide the aqueous solution of the copolymer with a pH of equal to or less than 4.5, wherein the acid comprises monoprotic organic acid and/or mineral acid, and
- adding the obtained aqueous solution of the copolymer into an aqueous suspension comprising solid particles to be flocculated.
Dependencies are inferred from the claim text.