JP2004209413A - Composition, polymer coagulant, and method for dehydrating sludge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a composition excellent in the ability to coagulate and dehydrate various types of sludge and excellent in the ability to coagulate and dehydrate especially even sludge with a high excess-sludge ratio, to obtain a polymer coagulant, and to provide a method for dehydrating sludge. <P>SOLUTION: The composition comprises (A) at least two amphoteric polymers each having a cationic monomer unit and an anionic monomer unit and each having a different cationic monomer/cationic monomer ratio and (B) a cationic polymer having an amidine unit. The polymer coagulant comprises the composition. The polymer coagulant is added to the sludge for dehydrating the sludge. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００３７】
【化２】

【００３８】
〔前記式（１）及び式（２）において、Ｒ^１及びＲ^２は、いずれも水素原子又はメチル基を表し、Ｘは陰イオンを表す。〕
Ｘの陰イオンとしては、塩素イオン、臭素イオン及びヨウ素イオン等のハロゲンイオン、ＮＯ_３ ⁻及びＣＨ_３ＣＯＯ⁻等が挙げられ、塩素イオン好ましい。
【００３９】
（Ｂ）成分としては、前記した式（１）及び（２）の単位の他に、下記の式（３）〜（５）の単位を含むものであっても良い。
【００４０】
【化３】

【００４１】
【化４】

【００４２】
【化５】

【００４３】
上記式（３）〜（５）において、Ｒ^１、Ｒ^２、Ｘは前記と同様の基を表し、Ｒ^３は、水素原子又は炭素数１〜４のアルキル基を表す。
【００４４】
（Ｂ）成分の分子量としては、０．５％塩粘度が０．１〜５０ｍＰａ・ｓのものが好ましく、より好ましくは１〜３０ｍＰａ・ｓである。
【００４５】
３．組成物
本発明の組成物は、前記（Ａ）成分及び（Ｂ）成分を混合することにより製造することができる。又、後記する汚泥の脱水や抄紙工程においては、それぞれの成分を別々に添加することもできる。
組成物における（Ａ）成分及び（Ｂ）成分の割合としては、目的に応じて適宜設定すれば良い。好ましい割合としては、（Ａ）成分が４０〜９９質量％及び（Ｂ）成分が１〜６０質量％の範囲であり、より好ましくは（Ａ）成分が５０〜９５質量％及び（Ｂ）成分が５〜５０質量％の範囲である。
【００４６】
４．用途
本発明の組成物は、種々の用途に応用することが可能である。例えば、高分子凝集剤及び塗料用等の増粘剤等が挙げられる。高分子凝集剤としては、汚泥脱水剤、及び歩留向上剤等の製紙工程における抄紙用薬剤等が挙げられる。
本発明で得られる組成物は、高分子凝集剤として有用なものであり、特に汚泥脱水剤及び歩留向上剤として有用なものであり、特に汚泥脱水剤として有用なものである。
以下、汚泥脱水剤及び歩留向上剤について説明する。
【００４７】
１）汚泥脱水剤及び汚泥の脱水方法
本発明の組成物は、特に汚泥脱水剤として有用なものである。
本発明の組成物を汚泥脱水剤として使用する場合は、組成物に、硫酸水素ナトリウム、硫酸ナトリウム及びスルファミン酸等、脱水処理に悪影響がでないかぎり公知の添加剤と混合して使用しても良い。
本発明の汚泥脱水剤（以下高分子凝集剤ということもある）は、種々の汚泥に適用可能であり、下水、し尿、並びに食品工業、化学工業及びパルプ又は製紙工業汚泥等の一般産業排水で生じる有機性汚泥及び凝集沈降汚泥を含む混合汚泥等を挙げることができる。
本発明の汚泥脱水剤は、特に繊維分が少ない汚泥、即ち余剰比率の高い汚泥に好ましく適用できるものである。具体的には、余剰比率が２０ＳＳ％以上の汚泥に好ましく適用でき、より好ましくは２０〜８０ＳＳ％の汚泥に適用できる。
【００４８】
本発明の汚泥脱水剤を使用する脱水方法は、具体的には、汚泥に汚泥脱水剤を添加した後、これにより汚泥フロックを形成させるものである。フロックの形成方法は、公知の方法に従えば良い。
【００４９】
又、必要に応じて、無機凝集剤、有機カチオン性化合物、カチオン性高分子凝集剤及びアニオン性高分子凝集剤を併用することができる。
【００５０】
無機凝集剤としては、硫酸アルミニウム、ポリ塩化アルミニウム、塩化第二鉄及び硫酸第一鉄及びポリ硫酸鉄等を例示できる。
【００５１】
有機カチオン性化合物としては、ポリマーポリアミン、ポリアミジン及びカチオン性界面活性剤等を例示できる。
【００５２】
無機凝集剤又は有機カチオン性化合物を添加した場合においては、ｐＨを４〜８とすることが、より効果的に汚泥の処理を行うことができるため好ましい。
ｐＨの調整方法としては、無機凝集剤又は有機カチオン性化合物を添加した後、当該ｐＨ値を満たす場合は、特にｐＨ調整の必要はないが、本発明で限定する範囲を満たさない場合は、酸又はアルカリを添加して調整する。
酸としては、塩酸、硫酸、酢酸及びスルファミン酸等を挙げることができる。
又、アルカリとしては、苛性ソーダ、苛性カリ、消石灰及びアンモニア等が挙げられる。
【００５３】
カチオン性高分子凝集剤としては、前記したカチオン性単量体の単独重合体及び前記したカチオン性単量体及びノニオン性単量体の共重合体等を挙げることができる。
【００５４】
アニオン性高分子凝集剤としては、前記したアニオン性単量体の単独重合体及び前記したアニオン性単量体及びノニオン性単量体の共重合体等を挙げることができる。
【００５５】
本発明において、繊維分が少ない汚泥、即ち余剰比率の高い汚泥を使用する場合においては、アニオン性高分子凝集剤と併用することが好ましい。
この場合において、凝集剤の汚泥への添加の順序としては、アニオン性高分子凝集剤を添加した後、高分子凝集剤を添加することが好ましい。
アニオン性高分子凝集剤としては、アニオン性単量体単位が３０モル％以上の共重合割合である共重合体が好ましく、４０モル％以上の共重合割合である共重合体がより好ましい。
この場合、アニオン性高分子凝集剤及び高分子凝集剤の併用割合としては、使用する全高分子凝集剤の合計量に対して、アニオン性高分子凝集剤が１〜７０質量％、高分子凝集剤が９９〜３０質量％であることが好ましい。
【００５６】
又、汚泥に添加する凝集剤は、使用する全高分子凝集剤の合計したカチオン性単量体単位とアニオン性単量体単位の割合が、下記式（４）を満足する様に添加することが好ましい。
【００５７】
【式５】
０．３≦Ｃａａｌｌ／Ａｎａｌｌ≦１５ （４）
【００５８】
〔尚、上記式（４）において、Ｃａａｌｌ及びＡｎａｌｌは、それぞれ、全使用高分子凝集剤の全アニオン性単量体単位量及び全カチオン性単量体単位量の合計量を１００モルに換算した場合における、全カチオン性単量体単位量及び全アニオン性単量体単位量のモル数を表す。〕
この範囲外で使用すると、フロックの造粒性が乏しくなったり、全凝集剤添加量が異常に増加したりし、得られるケーキの含水率が高くなることがある。
【００５９】
高分子凝集剤の汚泥に対する添加割合としては、５〜５００ｐｐｍが好ましく、ＳＳに対しては０．０５〜１質量％が好ましい。高分子凝集剤とその他の高分子凝集剤を併用する場合は、全高分子凝集剤の合計量が前記添加割合を満たすことが好ましい。
【００６０】
汚泥脱水剤、その他凝集剤の添加量、攪拌速度、攪拌時間等は、従来行われている脱水条件に従えば良い。
【００６１】
このようにして形成したフロックは、公知の手段を用いて脱水し、脱水ケーキとする。
【００６２】
脱水装置としては、スクリュープレス型脱水機、ベルトプレス型脱水機、フィルタープレス型脱水機及びスクリューデカンター等を例示することが出来る。
【００６３】
又、本発明の汚泥脱水剤は、濾過部を有する造粒濃縮槽を使用する脱水方法にも適用可能である。
具体的には、汚泥に、無機凝集剤を添加し、さらに汚泥脱水剤を添加した後、又は汚泥脱水剤と共に、該汚泥を濾過部を有する造粒濃縮槽に導入し、該濾過部からろ液を取り出すと共に造粒し、この造粒物を脱水機で脱水処理する方法等が挙げられる。
【００６４】
２）歩留向上剤及び抄紙方法
本発明の組成物を歩留向上剤として使用する場合、組成物原料としては、粉末状のものが好ましい。又、実際の使用に当たっては、組成物原料を水に溶解させ、０．０１〜０．５質量％水溶液として使用することが好ましく、より好ましくは０．０１〜０．１質量％水溶液である。
歩留向上剤の使用方法としては常法に従えば良く、例えば、紙料を抄紙機に送入する最終濃度に希釈する際、又は希釈後に添加する。
【００６５】
歩留向上剤が適用される紙料としては、通常の抄紙工程で使用されるものであればよく、通常、少なくともパルプ及び填料を含み、必要に応じて填料以外の添加剤、具体的には、サイズ剤、定着剤、紙力増強剤及び着色剤等を含むものである。
填料としては、白土、カオリン、アガライト、タルク、炭酸カルシウム、炭酸マグネシウム、硫酸石灰、硫酸バリウム、酸化亜鉛及び酸化チタン等が挙げられる。サイズ剤としては、アクリル酸・スチレン共重合体等が挙げられ、定着剤としては、硫酸バンド、カチオン澱粉及びアルキルケテンダイマー等が挙げられ、紙力増強剤としては、澱粉及びカチオン性又は両性ポリアクリルアミド等が挙げられる。
【００６６】
歩留向上剤の添加方法としては、組成物の水溶液を添加することもでき、又は組成物原料の両性高分子の水溶液を添加した後、別の両性高分子の水溶液を添加することもできる。
歩留向上剤の好ましい添加割合としては、紙料中の乾燥パルプ質量当たり、０．０５〜０．８質量％が好ましく、より好ましくは０．０５〜０．５質量％である。
歩留向上剤の添加後の紙料のｐＨとしては、５〜１０に維持することが好ましく、より好ましくは５〜８である。歩留向上剤の添加後に、紙料は直ちに抄紙機に送入される。
【００６７】
【実施例】
以下に実施例及び比較例を挙げ、本発明をより具体的に説明する。
なお、以下において、「部」とは質量部を意味する。
各例で使用した両性高分子及びアニオン性高分子凝集剤は、それぞれ下記表１及び表２に示す粉状のものを使用した。
又、各表における略号は、以下の意味を示す。
・ＤＡＣ：ジメチルアミノエチルアクリレートの塩化メチル４級塩
・ＡＡ：アクリル酸
・ＡＭＤ：アクリルアミド
【００６８】
【表１】

【００６９】
【表２】

【００７０】
○実施例１（高分子凝集剤の製造）
（Ａ）成分としてＣＲ−１の２５部とＡＲ−１の７５部からなるＢＬ−１の８０部と（Ｂ）成分としてポリアミジン〔ＣＶ−３００：東亞合成（株）製、カチオン当量６．１ｍｅｑ／ｇ、以下ＣＶ−３００という〕２０部を混合して、高分子凝集剤ＡＢＬ−１を製造した。
【００７１】
○実施例２〜同３（高分子凝集剤の製造）
（Ａ）成分及び（Ｂ）成分として、下記表４に示す高分子を使用する以外は実施例１と同様の方法により、高分子凝集剤を製造した。
【００７２】
【表３】

【００７３】
【表４】

【００７４】
○実施例４（汚泥の脱水方法）
古紙パルプ排水のスカム排水（ＳＳ：３９０００ｍｇ／ｌ、ＶＳＳ：２００００ｍｇ／ｌ、繊維分：８８０ｍｇ／ｌ）と余剰汚泥（ＳＳ：１２８００ｍｇ／ｌ、ＶＳＳ：９５００ｍｇ／ｌ、繊維分：４００ｍｇ／ｌ）の７０：３０（ＳＳ％）混合汚泥２００ｍｌを３００ｍｌのビーカーに採取し、これに高分子凝集剤ＡＢＬ−１を添加した後、空の３００ｍｌビーカーに移液し、計５回の移液操作を実施した後、スパーテルにて５０回攪拌してフロックを生成させた。この時のフロックの造粒程度を下記の３段階で評価し、得られたフロックの粒径を測定価した。
その後、８０メッシュ濾布をフィルターとして用いて、前記汚泥フロック分散液を重力濾過し、１０秒後の濾液容量を測定し、これを濾過速度とした。又、濾布上のケーキの自立性と得られた濾液の外観を下記の３段階で評価した。
得られたケーキを４ｍｍφのパンチングメタルに挟み、３０ｋｇ×３分間の荷重をかけ、パンチング穴から逸脱したケーキ重量を秤ると共に、濾布への剥離性を下記の３段階で評価した。
【００７５】
・造粒性
優；攪拌すると直ちに粒径の大きなフロックを形成した。良好；攪拌をしばらく続けると粒径の大きなフロックを形成した。不良；攪拌を続けても粒径の小さなフロックしか形成しなかった。
・濾過概観
優；完全に透明。良好；僅かに浮遊物有り。不良；多くの浮遊物有り。
・自立性
重力濾過時にフロック分散液を円筒に流し込み、濾過後、円筒を取り外したときにおいて、
優：完全にケーキが自力で立った。良好：僅かにケーキが流れた。不良：ケーキが流れてしまった。
・剥離性
ケーキを濾布からはがした時における濾布の状況が、
優：全く汚れなかった。良好：僅かに汚れた。不良：汚れてしまった。
【００７６】
○実施例５〜同８（汚泥の脱水方法）
汚泥に、表５に示すアニオン性高分子凝集剤を添加した後、表５に示す高分子凝集剤を添加する以外は実施例４と同様にして、汚泥の脱水処理を行なった。
実施例４と同様に評価した結果を表５に示す。
【００７７】
【表５】

【００７８】
○比較例１〜４（汚泥の脱水方法）
汚泥に、表６に示すアニオン性高分子凝集剤及び高分子凝集剤を使用した以外は実施例４と同様にして、汚泥の脱水処理を行なった。
実施例４と同様に評価した結果を表６に示す。
【００７９】
【表６】

【００８０】
○実施例９（汚泥の脱水方法）
製紙・パルプ排水混合汚泥（ＳＳ：３７１００ｍｇ／ｌ、ＶＳＳ：２４０００ｍｇ／ｌ、繊維分：８０００ｍｇ／ｌ）２００ｍｌを３００ｍｌのビーカーに採取し、高分子凝集剤ＡＢＬ−３を添加した以外は、実施例４と同様の方法で汚泥の脱水処理を行った。
実施例４と同様に評価した結果を表７示す。
【００８１】
○実施例１０（汚泥の脱水方法）
実施例９と同様の汚泥に、表７に示すアニオン性高分子凝集剤を添加した後、表７に示す高分子凝集剤を添加する以外は実施例９と同様にして、汚泥の脱水処理を行なった。
実施例４と同様に評価した結果を表７に示す。
【００８２】
【表７】

【００８３】
○比較例５〜７（汚泥の脱水方法）
実施例９と同様の汚泥に、表８に示すアニオン性高分子凝集剤及び高分子凝集剤を使用した以外は実施例９と同様にして、汚泥の脱水処理を行なった。
実施例４と同様に評価した結果を表８に示す。
【００８４】
【表８】

【００８５】
【発明の効果】
本発明の組成物は、高分子凝集剤として使用した場合、汚泥脱水剤として、種々の汚泥に対して、特に余剰比率の高い汚泥に対しても、濾過速度が速く、得られるフロックは粒径が大きく、自立性及び剥離性に優れるという各種凝集脱水性能に優れたものとなる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a composition and a polymer flocculant having excellent coagulation and dewatering properties, a high filtration rate, and excellent coagulation and dehydration performance capable of obtaining an excellent floc, and a sludge dewatering method using the same. It is.
[0002]
[Prior art]
Conventionally, a cationic polymer flocculant is used alone for sludge dehydration treatment. However, in recent years, due to an increase in the amount of sludge generated and deterioration of sludge properties, a conventional cationic polymer flocculant has been used. The treatment state is not always satisfactory in terms of the treatment amount, the water content of the dewatered cake, the SS recovery rate, and the removability of the cake from the filter cloth, and it is required to improve these points. ing.
[0003]
In order to improve these disadvantages of the conventional cationic polymer flocculant, various amphoteric polymer flocculants and various dehydration methods using the same have been proposed.
For example, (1) A method of dewatering sludge by adding a specific ion equivalent of a cation-rich amphoteric polymer flocculant to an organic sludge having a pH of 5 to 8 to which an inorganic flocculant containing no inorganic sludge is added (see Patent Document 1) (2) A method for dewatering sludge using an acrylate-based cationic polymer flocculant and an amphoteric polymer flocculant in combination with organic sludge having a pH of 5 to 8 (see Patent Document 2), and (3) an inorganic flocculant for sludge And the pH is set to less than 5, and a dehydration method in which an anion-rich amphoteric polymer flocculant having a specific composition is added (Patent Document 3) and (4) an inorganic flocculant, an anionic polymer flocculant and a cation rich in wastewater There is known a method of treating organic wastewater in which an amphoteric polymer flocculant is sequentially added (see Patent Document 4).
[0004]
[Patent Document 1]
Japanese Patent Publication No. 5-56199 (Claims)
[Patent Document 2]
Japanese Patent No. 2933627 (Claims)
[Patent Document 3]
Japanese Patent Publication No. 6-239 (Claims)
[Patent Document 4]
JP-A-6-134213 (Claims)
[0005]
[Problems to be solved by the invention]
However, although the dehydration methods (1) to (4) described above have some features, they are not necessarily effective methods for the recent tendency of hardly dewatering wastewater. .
That is, since there is a demand for lowering the COD value after the wastewater treatment, the ratio of the activated sludge treatment to the wastewater is higher than before, and the sludge subjected to the sludge dewatering treatment contains a large amount of excess sludge. In papermaking wastewater, since the recovery rate of the fiber content in the wastewater is increasing, the fiber content in the sludge is low, and the conventional polymer flocculant and the sludge dewatering method may not be able to cope with it.
[0006]
By the way, recently, as a method of dewatering sludge, a method using polyamidine has been used (Patent Document 5). Although the method using the polyamidine was an excellent method for the above-mentioned sludge dewatering method due to the high cationicity of the polyamidine, the growth of floc was sometimes insufficient. In order to solve this problem, the amount of polyamidine added may be increased, but the amount of polyamidine is expensive and the processing cost increases, so that the amount added is limited.
[0007]
The present inventor has studied diligently to find a composition, a polymer flocculant and a method of dewatering sludge which are excellent in coagulation and dewatering performance for various sludges, and particularly excellent in coagulation and dewatering performance even for sludge having a large surplus ratio. I went.
[0008]
[Patent Document 5]
JP-A-5-192513 (Claims)
[0009]
[Means for Solving the Problems]
The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, two or more amphoteric polymers having different copolymerization ratios of a cationic monomer unit and an anionic monomer unit, and polyamidine. The present inventors have found that the composition used in combination is effective and completed the present invention.
Hereinafter, the present invention will be described in detail.
In this specification, acrylate or methacrylate is represented as (meth) acrylate, acrylamide or methacrylamide is represented as (meth) acrylamide, acrylic acid or methacrylic acid is represented as (meth) acrylic acid, and acrylonitrile or methacrylonitrile is used. Is represented as (meth) acrylonitrile.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
1. (A) Two or more amphoteric polymers
The component (A) is a two- or more-type amphoteric polymer having a cationic monomer unit and an anionic monomer unit, and having different proportions of the monomer units.
The amphoteric polymer constituting the component (A) may be a copolymer having a cationic monomer unit and an anionic monomer unit as essential constituent monomer units.
[0011]
Examples of the cationic monomer include dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and diethylamino-2-hydroxypropyl (meth) acrylate. Tertiary salts; quaternary salts such as alkyl halide adducts such as methyl chloride adduct of dialkylaminoalkyl (meth) acrylate and aryl halide adducts such as benzyl chloride adduct; N, N-dimethyl (meth) acrylamide Tertiary salts such as hydrochloride salts and sulfate salts of dialkyl (meth) acrylamide and the like; halogenated alkyl adducts such as methyl chloride adduct of dialkyl (meth) acrylamide and aryl halide adducts such as benzyl chloride adduct and the like. And the like.
[0012]
Examples of the anionic monomer include (meth) acrylic acid and alkali metal salts or ammonium salts such as sodium salt thereof; maleic acid and the like and alkali metal salts thereof; acrylamide alkylalkane sulfone such as acrylamide-2-methylpropanesulfonic acid Acid and its alkali metal salt or ammonium salt; and vinyl sulfonic acid and its alkali metal salt or ammonium salt.
[0013]
As the amphoteric polymer, a monomer other than the above-mentioned monomers, specifically, a nonionic monomer may be used in combination, if necessary. Nonionic monomers include (meth) acrylamide, dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate, dialkylaminoalkyl (meth) acrylamides such as dialkylaminopropyl (meth) acrylamide, styrene, acrylonitrile , Vinyl acetate, alkyl (meth) acrylate, alkoxyalkyl (meth) acrylate, vinyl pyridine, vinyl imidanol and allylamine. Among these, (meth) acrylamide is preferred.
[0014]
Any of these monomers can be used alone or in combination of two or more.
[0015]
Preferred combinations of the monomers in the present invention include (1) a tertiary or quaternary salt of dialkylaminoalkyl acrylate as a cationic monomer, and an acrylate and a nonionic monomer as an anionic monomer. (2) tertiary or quaternary salt of dialkylaminoalkyl methacrylate as a cationic monomer, acrylate as anionic monomer and acrylamide as a nonionic monomer (3) Tertiary or quaternary salt of dialkylaminoalkyl methacrylate and tertiary or quaternary salt of dialkylaminoalkyl acrylate as cationic monomer, acrylate and nonionic as anionic monomer There is a copolymer composed of acrylamide as a monomer.
[0016]
The amphoteric polymer in the present invention preferably has a 0.5% salt viscosity of 10 to 120 mPa · s, which is an index of the molecular weight, when used as a polymer flocculant described later. In order to achieve the dehydration treatment described above, the pressure is more preferably 15 to 90 mPa · s.
In the present invention, the 0.5% salt viscosity refers to a sample obtained by dissolving 0.5% of an amphoteric polymer in a 4% aqueous sodium chloride solution at 25 ° C. using a B-type viscometer with a rotor No. It refers to the value measured at 60 rpm using 1 or 2.
[0017]
The method for producing the amphoteric polymer is not particularly limited, and a general polymerization method can be employed. For example, in the case of aqueous solution polymerization, thermal radical polymerization is performed using potassium persulfate, ammonium persulfate, 2,2′-azobis (2-amidinopropane) dihydrochloride, a redox polymerization initiator, or the like as a polymerization initiator. And photoradical polymerization by irradiating ultraviolet rays using a benzoin and acetophenone type photopolymerization initiator. In the case of reverse-phase emulsion polymerization, the polymerization may be carried out using a water-insoluble initiator such as azobisisobutyronitrile and benzoyl peroxide in addition to the polymerization initiator.
[0018]
The obtained gel polymer is then cut and cut by a known method. The shredded polymer is dried at a temperature of about 60 to 150 ° C. using a dryer such as a band dryer, a rotary dryer, a far-infrared dryer and a vibrating fluid dryer, and a roll grinder. And the like to make a powdery copolymer, and the particle size is adjusted.
As the amphoteric polymer of the composition raw material of the present invention, a powdery product is preferably used.
[0019]
As the component (A) of the present invention, any component may be used as long as it contains two or more amphoteric polymers having different proportions of the cationic monomer unit and the anionic monomer unit.
[0020]
Preferable combinations of amphoteric polymers include those in which the molar ratio Ca / An of cationic monomer units to anionic monomer units satisfies Ca / An ≧ 1 (hereinafter referred to as cation-rich amphoteric polymer). Those satisfying Ca / An <1 (hereinafter referred to as an anion-rich amphoteric polymer) are used in combination. The cation-rich amphoteric polymer preferably has a Ca / An of 1.5 to 10.0, and the anion-rich amphoteric polymer preferably has a Ca / An of 0.5 to 0.9.
The cation-rich amphoteric polymer and the anion-rich amphoteric polymer can be obtained by copolymerizing a cationic monomer unit and an anionic monomer unit so as to satisfy the monomer unit ratio.
[0021]
As another preferable combination of the amphoteric polymers, the ratio of the cationic monomer unit and the anionic monomer unit in the amphoteric polymer satisfies the following formula (1) (hereinafter, cation-rich amphoteric polymer 1). ) And an amphoteric polymer satisfying the following formula (2) (hereinafter referred to as a cation-rich amphoteric polymer 2), and further, those satisfying the formula (3).
[0022]
[Equation 2]
Ca₁/ An₁≧ 1 ・ ・ ・ ・ (1)
[0023]
[Equation 3]
Ca₂/ An₂≧ 1 ・ ・ ・ ・ (2)
[0024]
(Equation 4)
│ (Ca₁-An₁)-(Ca₂-An₂) │ ≧ 1.5 ・ ・ ・ ・ (3)
[0025]
[In the above formulas (1) to (3), Ca₁And An₁Is the number of moles of the total amount of the cationic monomer units and the total number of the anionic monomer units when the total amount of all the constituent monomer units in the cation-rich amphoteric polymer 1 is converted into 100 moles, respectively. And Ca₂And An₂Represents the total number of cationic monomer units and the total number of anionic monomer units in the cation-rich amphoteric polymer 2 in the same manner as described above. ]
[0026]
Ca₁/ An₁Is preferably from 1.2 to 40.0, and Ca₂/ An₂Is preferably 1.2 to 40.0.
│ (Ca₁-An₁)-(Ca₂-An₂Is preferably 1.5 to 40.0. When this value is less than 1.5, when used as a coagulant, high-performance coagulation performance as in the present invention may not be exhibited.
[0027]
The cation-rich amphoteric polymers 1 and 2 can be obtained by copolymerizing a cationic monomer unit and an anionic monomer unit so as to satisfy the monomer unit ratio.
[0028]
The proportion of the amphoteric polymer in the component (A) may be appropriately set according to the purpose.
When a cation-rich amphoteric polymer and an anion-rich amphoteric polymer are used together, the cation-rich amphoteric polymer is preferably in a range of 20 to 60% by mass and the anion-rich amphoteric polymer is preferably in a range of 40 to 80% by mass.
When the cation-rich amphoteric polymers 1 and 2 are used in combination, the cation-rich amphoteric polymer 1 is preferably in a range of 10 to 90% by mass and the cation-rich amphoteric polymer 2 is preferably in a range of 90 to 10% by mass.
[0029]
As the cation-rich amphoteric polymer and the anion-rich amphoteric polymer, or as the cation-rich amphoteric polymers 1 and 2, each can be used alone or in combination of two or more. It is convenient and preferable to use one each of an anion-rich amphoteric polymer or a cation-rich amphoteric polymer 1 and 2.
[0030]
2. (B) Cationic polymer having amidine unit
As the component (B), various compounds can be used as long as the polymer has an amidine unit and a cationic property.
[0031]
As a preferred component (B), (meth) acrylonitrile and a vinyl monomer capable of forming a primary amino group are copolymerized to produce a copolymer, and a primary amino group is contained in the copolymer. After the formation, there may be mentioned those in which an amidine unit is formed by a ring-closing reaction between a primary amino group and a nitrile group in the copolymer.
[0032]
Examples of the vinyl monomer capable of forming a primary amino group include N-vinylamide such as N-vinylformamide, N-vinylacetamide, N-vinylphthalimide, N-vinylsuccinimide and N-vinylurethane. Can be
[0033]
Examples of a method for generating a primary amino group from a copolymer include a hydrolysis reaction with an acid-base, a solvolysis reaction such as alcoholysis and ammonolysis in the case of a copolymer of N-vinylamide, and the like.
[0034]
The ring-closing reaction between the amino group and the nitrile group may be performed according to a conventional method, and is carried out under acidic conditions at 80 to 150 ° C, preferably 90 to 120 ° C.
[0035]
The amidine unit obtained by the above method is represented by the following formula (1) and / or formula (2). The proportion of the amidine unit in the component (B) is preferably from 30 to 90 mol%, more preferably from 40 to 80 mol%.
The cation equivalent of the component (B) is preferably from 5.0 to 7.0 meq / g, more preferably from 5.5 to 6.5 meq / g. In the present invention, the ion equivalent means a value measured by a colloid titration method.
[0036]
Embedded image

[0037]
Embedded image

[0038]
[In the above formulas (1) and (2), R¹And R²Represents a hydrogen atom or a methyl group, and X represents an anion. ]
X anions include halogen ions such as chlorine ion, bromine ion and iodine ion, NO₃ ⁻And CH₃COO⁻And the like, and chlorine ions are preferred.
[0039]
The component (B) may include units of the following formulas (3) to (5) in addition to the units of the above formulas (1) and (2).
[0040]
Embedded image

[0041]
Embedded image

[0042]
Embedded image

[0043]
In the above formulas (3) to (5), R¹, R², X represents the same group as described above, and R³Represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
[0044]
The molecular weight of the component (B) is preferably such that the 0.5% salt viscosity is 0.1 to 50 mPa · s, more preferably 1 to 30 mPa · s.
[0045]
3. Composition
The composition of the present invention can be produced by mixing the components (A) and (B). In the later-described sludge dewatering and papermaking processes, each component can be added separately.
The ratio of the component (A) and the component (B) in the composition may be appropriately set according to the purpose. As a preferable ratio, the component (A) is in the range of 40 to 99% by mass and the component (B) is in the range of 1 to 60% by mass, and more preferably the component (A) is 50 to 95% by mass and the component (B) is It is in the range of 5 to 50% by mass.
[0046]
4. Use
The composition of the present invention can be applied to various uses. For example, polymer flocculants and thickeners for paints and the like can be mentioned. Examples of the polymer flocculant include a papermaking chemical in a papermaking process such as a sludge dewatering agent and a retention aid.
The composition obtained in the present invention is useful as a polymer flocculant, particularly useful as a sludge dewatering agent and a retention aid, and particularly useful as a sludge dewatering agent.
Hereinafter, the sludge dewatering agent and the yield improver will be described.
[0047]
1) Sludge dewatering agent and sludge dewatering method
The composition of the present invention is particularly useful as a sludge dewatering agent.
When the composition of the present invention is used as a sludge dewatering agent, the composition may be used by mixing with known additives such as sodium hydrogen sulfate, sodium sulfate and sulfamic acid as long as the dehydration treatment is not adversely affected. .
The sludge dewatering agent of the present invention (hereinafter also referred to as a polymer flocculant) is applicable to various sludges, and is used in general industrial wastewater such as sewage, night soil, and sludge in the food industry, chemical industry, and pulp or paper industry. Mixed sludge including the resulting organic sludge and coagulated settled sludge can be mentioned.
The sludge dewatering agent of the present invention can be preferably applied to sludge having a low fiber content, that is, sludge having a high surplus ratio. Specifically, it can be preferably applied to sludge having a surplus ratio of 20 SS% or more, and more preferably, to sludge having a surplus ratio of 20 to 80 SS%.
[0048]
In the dewatering method using the sludge dewatering agent of the present invention, specifically, a sludge dewatering agent is added to sludge, and thereby sludge flocs are formed. The method for forming the flocs may be a known method.
[0049]
If necessary, an inorganic coagulant, an organic cationic compound, a cationic polymer coagulant and an anionic polymer coagulant can be used in combination.
[0050]
Examples of the inorganic coagulant include aluminum sulfate, polyaluminum chloride, ferric chloride, ferrous sulfate, and polyiron sulfate.
[0051]
Examples of the organic cationic compound include polymer polyamines, polyamidines, and cationic surfactants.
[0052]
When an inorganic coagulant or an organic cationic compound is added, it is preferable to adjust the pH to 4 to 8 because the sludge can be more effectively treated.
As a method for adjusting the pH, if an inorganic coagulant or an organic cationic compound is added and then the pH value is satisfied, pH adjustment is not particularly necessary. Or, it is adjusted by adding an alkali.
Examples of the acid include hydrochloric acid, sulfuric acid, acetic acid, and sulfamic acid.
Examples of the alkali include caustic soda, caustic potash, slaked lime, and ammonia.
[0053]
Examples of the cationic polymer coagulant include a homopolymer of the above-mentioned cationic monomer and a copolymer of the above-mentioned cationic monomer and nonionic monomer.
[0054]
Examples of the anionic polymer coagulant include a homopolymer of the above-described anionic monomer and a copolymer of the above-described anionic monomer and nonionic monomer.
[0055]
In the present invention, when using sludge having a small fiber content, that is, sludge having a high surplus ratio, it is preferable to use the sludge together with an anionic polymer flocculant.
In this case, the order of adding the flocculant to the sludge is preferably to add the polymer flocculant after adding the anionic polymer flocculant.
As the anionic polymer coagulant, a copolymer having an anionic monomer unit having a copolymerization ratio of 30 mol% or more is preferable, and a copolymer having a copolymerization ratio of 40 mol% or more is more preferable.
In this case, as the combined ratio of the anionic polymer flocculant and the polymer flocculant, the amount of the anionic polymer flocculant is 1 to 70% by mass, based on the total amount of all the polymer flocculants used, Is preferably from 99 to 30% by mass.
[0056]
The coagulant to be added to the sludge may be added so that the total ratio of cationic monomer units and anionic monomer units of all the polymer coagulants used satisfies the following formula (4). preferable.
[0057]
(Equation 5)
0.3 ≦ Caall / Anall ≦ 15 (4)
[0058]
[In the above formula (4), Caall and Anal are respectively converted to the total amount of all anionic monomer units and all cationic monomer units of all polymer flocculants used in 100 mol. In this case, the total number of the cationic monomer units and the total number of the anionic monomer units are represented by the number of moles. ]
If used outside this range, the floc may have poor granulation properties, the total amount of flocculant added abnormally increases, and the resulting cake may have a high water content.
[0059]
The addition ratio of the polymer flocculant to the sludge is preferably 5 to 500 ppm, and is preferably 0.05 to 1% by mass with respect to SS. When a polymer coagulant is used in combination with another polymer coagulant, the total amount of all the polymer coagulants preferably satisfies the above-mentioned addition ratio.
[0060]
The addition amount of the sludge dewatering agent and other coagulants, the stirring speed, the stirring time, and the like may be in accordance with conventionally performed dehydration conditions.
[0061]
The floc thus formed is dehydrated using a known means to obtain a dewatered cake.
[0062]
Examples of the dehydrator include a screw press dehydrator, a belt press dehydrator, a filter press dehydrator, and a screw decanter.
[0063]
Further, the sludge dewatering agent of the present invention is also applicable to a dewatering method using a granulation and concentration tank having a filtration unit.
Specifically, to the sludge, after adding an inorganic flocculant and further adding a sludge dewatering agent, or together with the sludge dewatering agent, the sludge is introduced into a granulation and concentration tank having a filtration unit, and filtered from the filtration unit. A method of removing the liquid, granulating the granulated product, and dehydrating the granulated product with a dehydrator is used.
[0064]
2) Retention improver and papermaking method
When the composition of the present invention is used as a retention aid, the raw material for the composition is preferably a powder. Further, in actual use, it is preferable to dissolve the composition raw material in water and use it as a 0.01 to 0.5% by mass aqueous solution, more preferably a 0.01 to 0.1% by mass aqueous solution.
The retention aid may be used in accordance with a conventional method, for example, when the paper stock is diluted to the final concentration to be fed into a paper machine or after the dilution.
[0065]
The paper material to which the retention aid is applied may be any material used in a usual papermaking process, and usually contains at least pulp and filler, and if necessary, additives other than filler, specifically, , A sizing agent, a fixing agent, a paper strength enhancer, a coloring agent and the like.
Examples of the filler include clay, kaolin, agarite, talc, calcium carbonate, magnesium carbonate, lime sulfate, barium sulfate, zinc oxide and titanium oxide. Examples of the sizing agent include acrylic acid / styrene copolymers, and examples of the fixing agent include a sulfuric acid band, cationic starch and alkyl ketene dimer, and examples of the paper strength enhancer include starch and cationic or amphoteric poly. Acrylamide and the like can be mentioned.
[0066]
As a method for adding the retention aid, an aqueous solution of the composition can be added, or an aqueous solution of the amphoteric polymer as a raw material of the composition can be added, and then another aqueous solution of the amphoteric polymer can be added.
The preferable addition ratio of the retention aid is 0.05 to 0.8% by mass, more preferably 0.05 to 0.5% by mass, based on the dry pulp mass in the stock.
The pH of the stock after the addition of the retention aid is preferably maintained at 5 to 10, more preferably 5 to 8. After the addition of the retention aid, the stock is immediately sent to the paper machine.
[0067]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
In the following, “parts” means parts by mass.
As the amphoteric polymer and the anionic polymer coagulant used in each example, powdery ones shown in Tables 1 and 2 below were used.
The abbreviations in each table have the following meanings.
・ DAC: Methyl chloride quaternary salt of dimethylaminoethyl acrylate
・ AA: Acrylic acid
・ AMD: Acrylamide
[0068]
[Table 1]

[0069]
[Table 2]

[0070]
-Example 1 (production of polymer flocculant)
(A) 80 parts of BL-1 consisting of 25 parts of CR-1 and 75 parts of AR-1 as a component and polyamidine (CV-300: manufactured by Toagosei Co., Ltd., cation equivalent 6.1 meq) as a component (B) / G, hereinafter referred to as CV-300], to produce a polymer flocculant ABL-1.
[0071]
○ Examples 2 and 3 (Production of polymer flocculant)
A polymer flocculant was produced in the same manner as in Example 1 except that the polymers shown in Table 4 below were used as the components (A) and (B).
[0072]
[Table 3]

[0073]
[Table 4]

[0074]
○ Example 4 (Sludge dewatering method)
Waste paper pulp wastewater scum wastewater (SS: 39000 mg / l, VSS: 20000 mg / l, fiber content: 880 mg / l) and excess sludge (SS: 12800 mg / l, VSS: 9500 mg / l, fiber content: 400 mg / l) 200 ml of 70:30 (SS%) mixed sludge was collected in a 300 ml beaker, a polymer flocculant ABL-1 was added thereto, and then transferred to an empty 300 ml beaker, and a total of 5 transfer operations were performed. After that, the mixture was stirred 50 times with a spatula to generate floc. At this time, the degree of granulation of the floc was evaluated on the following three scales, and the particle size of the obtained floc was measured.
Thereafter, the sludge floc dispersion was gravity-filtered using an 80 mesh filter cloth as a filter, and the filtrate volume after 10 seconds was measured. In addition, the self-sufficiency of the cake on the filter cloth and the appearance of the obtained filtrate were evaluated on the following three scales.
The obtained cake was sandwiched between 4 mmφ punching metals, a load of 30 kg × 3 minutes was applied, the weight of the cake deviating from the punching holes was weighed, and the releasability to the filter cloth was evaluated in the following three steps.
[0075]
・ Granulation
Excellent: A floc having a large particle size was formed immediately upon stirring. Good; flocculation with a large particle size was formed when stirring was continued for a while. Poor; only floc having a small particle size was formed even when stirring was continued.
・ Overview of filtration
Excellent; completely transparent. Good; slightly suspended matter. Poor; many floating substances.
·Autonomy
When the floc dispersion is poured into the cylinder during gravity filtration, and after filtration, when the cylinder is removed,
Yu: The cake stood completely on its own. Good: Slight cake flow. Bad: The cake has flowed.
・ Releasability
The condition of the filter cloth when the cake was removed from the filter cloth,
A: It was not dirty at all. Good: Slightly soiled. Bad: dirty.
[0076]
○ Examples 5 to 8 (Sludge dewatering method)
After adding the anionic polymer flocculant shown in Table 5 to the sludge, the sludge was dewatered in the same manner as in Example 4 except that the polymer flocculant shown in Table 5 was added.
Table 5 shows the results of the evaluation performed in the same manner as in Example 4.
[0077]
[Table 5]

[0078]
○ Comparative Examples 1-4 (sludge dewatering method)
The sludge was dehydrated in the same manner as in Example 4 except that the anionic polymer flocculant and the polymer flocculant shown in Table 6 were used for the sludge.
Table 6 shows the results of the evaluation performed in the same manner as in Example 4.
[0079]
[Table 6]

[0080]
○ Example 9 (Sludge dewatering method)
Except that 200 ml of papermaking / pulp wastewater mixed sludge (SS: 37100 mg / l, VSS: 24000 mg / l, fiber content: 8000 mg / l) was collected in a 300 ml beaker, and a polymer flocculant ABL-3 was added. In the same manner as in No. 4, sludge was dewatered.
Table 7 shows the results of the evaluation performed in the same manner as in Example 4.
[0081]
○ Example 10 (Sludge dewatering method)
After adding the anionic polymer flocculant shown in Table 7 to the same sludge as in Example 9, the dewatering treatment of the sludge was performed in the same manner as in Example 9 except that the polymer flocculant shown in Table 7 was added. Done.
Table 7 shows the results of the evaluation performed in the same manner as in Example 4.
[0082]
[Table 7]

[0083]
○ Comparative Examples 5 to 7 (Sludge dewatering method)
The sludge was dehydrated in the same manner as in Example 9 except that the anionic polymer flocculant and the polymer flocculant shown in Table 8 were used in the same sludge as in Example 9.
Table 8 shows the results of the evaluation performed in the same manner as in Example 4.
[0084]
[Table 8]

[0085]
【The invention's effect】
When the composition of the present invention is used as a polymer flocculant, as a sludge dewatering agent, for various kinds of sludge, especially for sludge having a high surplus ratio, the filtration rate is high, and the obtained floc has a particle size of And excellent in various coagulation dehydration performances such as excellent self-sustainability and peelability.

Claims (5)

It comprises (A) two or more kinds of amphoteric polymers having a cationic monomer unit and an anionic monomer unit, and different proportions of the monomer units, and (B) a cationic polymer having an amidine unit. Composition. A polymer flocculant comprising the composition according to claim 1. A method for dewatering sludge, comprising adding the polymer flocculant according to claim 2 to sludge and then dewatering the sludge. The sludge dewatering method according to claim 3, further comprising using an anionic polymer flocculant in combination. The polymer flocculant is added to the sludge so that the total ratio of cationic monomer units and anionic monomer units of all the polymer flocculants used satisfies the following formula (4). The method for dewatering sludge according to claim 3 or 4.
(Equation 1)
0.3 ≦ Caall / Anall ≦ 15 (4)
[In the above formula (4), Caall and Anal are respectively converted to the total amount of all anionic monomer units and all cationic monomer units of all polymer flocculants used in 100 mol. In this case, the total number of the cationic monomer units and the total number of the anionic monomer units are represented by the number of moles. ]