JP3795102B2 - Sludge solidification material and sludge solidification method - Google Patents

Description

【００１９】
（ただし、Ｒは水素またはメチル基であり、Ｘは全オキシアルキレン基に対するオキシエチレン基のモル分率が５０モル％以上である炭素数２〜４のオキシアルキレン基であり、Ｙは炭素数１〜５のアルコキシ基、フェノキシ基、または炭素数１〜９のアルキル基を１〜３個置換基として有するオキシアルキルフェニル基であり、ｎは３〜１００の正数である。）
一般式（１）にて表されるノニオン性単量体として、例えば、メトキシポリエチレングリコールモノ（メタ）アクリレート、メトキシポリエチレングリコール・ポリプロピレングリコールモノ（メタ）アクリレート、メトキシポリエチレングリコール・ポリブチレングリコールモノ（メタ）アクリレート、エトキシポリエチレングリコールモノ（メタ）アクリレート、エトキシポリエチレングリコール・ポリプロピレングリコールモノ（メタ）アクリレート、エトキシポリエチレングリコール・ポリブチレングリコールモノ（メタ）アクリレート、フェノキシポリエチレングリコールモノ（メタ）アクリレート、ベンジルオキシポリエチレングリコールモノ（メタ）アクリレート等を挙げることができ、これらの１種または２種以上を用いることができる。
【００２０】
上記した単量体の中でも、一般式（１）で表されるノニオン性単量体、アミド基含有単量体およびスルホン酸基含有単量体の使用が好ましい。
【００２１】
一般式（１）で表されるノニオン性単量体を用いる場合、単量体組成として、ノニオン性単量体３０〜１００重量％、ノニオン性単量体と共重合可能な単量体７０〜０重量％とすることが好ましい。ノニオン性単量体と共重合可能な好ましい単量体としては、前記した、不飽和モノカルボン酸系単量体、不飽和スルホン酸系単量体を挙げることができる。
【００２２】
アミド基含有単量体を用いる場合、単量体組成として、アミド基含有単量体４０〜１００重量％、アミド基含有単量体と共重合可能な単量体６０〜０重量％とすることが好ましい。アミド基含有単量体と共重合可能な好ましい単量体としては、前記した、不飽和モノカルボン酸系単量体、不飽和スルホン酸系単量体を挙げることができる。
【００２３】
スルホン酸基含有単量体を用いる場合、単量体組成として、スルホン酸基含有単量体２０〜１００重量％、スルホン酸基含有単量体と共重合可能な単量体８０〜０重量％とすることが好ましい。スルホン酸基含有単量体と共重合可能な好ましい単量体としては、前記した、不飽和モノカルボン酸系単量体、アミド基含有
単量体および一般式（１）で表されるノニオン性単量体を挙げることができる。
【００２４】
高吸水性樹脂は、通常、前記単量体を、その単量体に対して 0.001〜５モル％の架橋剤の存在下にて重合して得られる。
【００２５】
架橋剤としては、例えば、エチレングリコールジ（メタ）アクリレート、ジエチレングリコールジ（メタ）アクリレート、トリエチレングリコールジ（メタ）アクリレート、プロピレングリコールジ（メタ）アクリレート、ポリエチレングリコールジ（メタ）アクリレート、トリメチロールプロパントリ（メタ）アクリレート、ペンタエリスリトールトリ（メタ）アクリレート、ペンタエリスリトールジ（メタ）アクリレート、Ｎ，Ｎ−メチレンビス（メタ）アクリルアミド、イソシアヌル酸トリアリル、トリメチロールプロパンジアリルエーテル等の１分子中にエチレン性不飽和基を２個以上有する化合物；単量体中のカルボキシル基と反応する官能基を２個以上有するものとして例えばエチレングリコール、ジエチレングリコール、トリエチレングリコール、ポリエチレングリコール、グリセリン、ポリグリセリン、プロピレングリコール、ジエタノールアミン、トリエタノールアミン、ポリプロピレングリコール、ペンタエリスリトール、ソルビット、ソルビタン、グルコース、マンニット、マンニタン、ショ糖等の多価アルコール類や、エチレングリコールジグリシジルエーテル、グリセリンジグリシジルエーテル、ポリエチレングリコールジグリシジルエーテル、プロピレングリコールジグリシジルエーテル、ポリプロピレングリコールジグリシジルエーテル、ネオペンチルグリコールジグリシジルエーテル、1,6-ヘキサンジオールジグリシジルエーテル、トリメチロールプロパンジグリシジルエーテル、トリメチロールプロパントリグリシジルエーテル、グリセリントリグリシジルエーテル等のポリエポキシ化合物等が挙げられ、これらの１種または２種以上の混合物を用いることができる。
【００２６】
架橋剤として、多価アルコールを用いる場合には１５０〜２５０℃で、ポリエポキシ化合物を用いる場合には５０〜２５０℃で重合中あるいは重合後に熱処理することが好ましい。
【００２７】
架橋剤の使用量は、前記単量体に対して 0.001〜５モル％とすることが好ましい。５モル％を越える量では、架橋重合体である得られる高吸水性樹脂の架橋密度が大きくなりすぎて吸水能が低下する結果、固化性が不良となる傾向がある一方、逆に 0.001モル％未満の少ない量では、架橋密度が小さすぎて初期の吸収速度が著しく低下する結果、固化性が低下する。
【００２８】
高吸水性樹脂を得るための重合方法は、従来から知られている公知の方法が採用でき、例えばラジカル重合触媒を用いる方法、放射線・電子線・紫外線等を照射する方法等が挙げられる。ラジカル重合触媒としては、例えば過酸化水素、ベンゾイルパーオキサイド、キュメンハイドロパーオキサイド等の過酸化物：アゾビスイソブチロニトリル、2,2'- アゾビス-2- アミジノプロパン塩酸塩等のアゾ化合物：過硫酸アンモニウム、過硫酸カリウム、過硫酸ナトリウム等の過硫酸塩等が挙げられる。これらの重合開始剤は２種以上混合して使用することも可能であり、さらに亜硫酸塩、Ｌ−アスコルビン酸、第２鉄塩等の還元剤との組合わせによるレドックス系開始剤として使用してもよい。
【００２９】
重合温度は用いる触媒の種類により異なるが、得られる高吸水性樹脂の分子量が充分大きくでき、また重合を完結させる意味から２０〜１００℃の範囲であることが好ましい。
【００３０】
単量体を溶媒に溶解希釈してから重合に供することも自由であり、このような重合系溶媒としては、例えば水、メタノール、エタノール、アセトン、ジメチルホルムアミド等やこれらの混合物や、ベンゼン、トルエン、シクロヘキサン等の有機溶媒を使用することができる。
【００３１】
単量体に対し溶媒溶液を用いる場合の溶液濃度には特に制限はないが、重合反応の制御の容易さと収率・経済性を考慮すれば、２０重量％〜飽和濃度以下であることが好ましい。
【００３２】
重合形態としては、溶液重合法の他に、例えばソルビタン脂肪酸エステル、ショ糖脂肪酸エステル、グリセリン脂肪酸エステル、ポリグリセリン脂肪酸エステル、エチルセルロース、セルロースアセテート等のセルロースエステル、セルロースエーテル、α−オレフィン−無水マレイン酸共重合体等のカルボキシル基含有重合体等を分散剤として用いて疎水性有機溶媒中に単量体水溶液を分散させて行う逆相懸濁重合法、注型重合法、双腕型ニーダーのせん断力による含水ゲル状重合体を細分化しながら重合する方法、薄膜重合法、噴霧重合法等の種々の方法を採用できる。
【００３３】
上記のようにして得られた架橋重合体である高吸水性樹脂の表面近傍に対し親水性架橋剤によってさらに架橋し、表面の近傍と内部との間に架橋密度勾配を導入し、それによって初期吸水速度を速めたものを用いることもできる。
【００３４】
このような親水性架橋剤としては、例えばグリセリン、エチレングリコール、ペンタエリスリトール等の多価アルコール類：エチレングリコールジグリシジルエーテル等のポリエポキシ化合物：エチレンジアミン、ジエチレントリアミン、トリエチレンテトラアミン、テトラエチレンペンタミン、ペンタエチレンヘキサミン、ポリエチレンイミン等の多価アミン類：グルタルアルデヒド、グリオキサール等の多価アルデヒド類：塩化アルミニウム、塩化マグネシウム、塩化カルシウム、硫酸アルミニウム、硫酸マグネシウム、硫酸カルシウム等の多価金属塩類等が挙げられる。
【００３５】
これらの親水性架橋剤の使用量は、表面近傍を架橋しようとする高吸水性樹脂に対して、 0.005〜５重量％の範囲が好ましい。また、高吸水性樹脂の表面近傍を架橋する方法についても特に制限はなく、高吸水性樹脂の粉体に親水性架橋剤をそのままあるいは溶液の形で、混合したのち必要により加熱する方法や、高吸水性樹脂の粉体を疎水性有機溶媒中に分散させて得た分散液に親水性架橋剤を混合したのち必要により加熱する方法等を採用することができる。
【００３６】
高吸水性樹脂の粒子径は特に制限はないが、通常１０〜１０００μｍの粒径が、取り扱い性や工業的に容易に得られるために賞用されている。高吸水性樹脂の吸水能については特に制限はないが、１％セメント水に対する吸水倍率が下記の測定方法で１０ｇ／ｇ以上の吸水倍率を有するものが好ましい。
（吸水倍率の測定方法）
脱イオン水９９重量部に対し、ポルトランドセメント（トクヤマ社製）１重量部を入れ、２時間攪拌して混合液を得た。ついで、その混合液を、Ｎｏ．２ろ紙でろ過して、そのろ液を１％セメント水とした。
【００３７】
吸水倍率の測定では、まず、不織布等の透水性を有する素材からなるティーバック状の袋内に高吸水製樹脂約 0.1ｇを秤量して加えた後、上記袋を、上記１％セメント水１００ｇに２４時間浸漬した後、上記袋の重量を測定し、次式にしたがって吸水倍率を算出した。
【００３８】
吸水倍率（ｇ／ｇ）＝（Ｂ−Ｃ）／Ａ
Ａ：採取した高吸水性樹脂粉末の重量（ｇ）
Ｂ：吸水後の袋を含めた全重量（ｇ）
Ｃ：空試験における袋を含めた重量（ｇ）
本発明の汚泥固化材は、それ単独使用にて強度を有し、しかも離水量の少ない汚泥固化物が得られるが、必要に応じて、他の固化材と併用することはもちろん可能である。
【００３９】
このような他の固化材として、グアーガム、ローカストビンガム、クインスシードガム、アラビノガラクタンガム、アラビアガム、トラガントガム、澱粉、ザンサンガム、ザンコート、ゼラチン、サイリュームガム、多糖類、アルギン酸塩類、カルボキシメチルセルロース、カルボキシメチルハイドロオキシエチルセルロースなどの天然あるいは半合成高分子物質や、ポリビニルアルコール、ポリビニルピロリドン、ポリアクリルアミド、ポリアクリル酸ナトリウム、ポリエチレンオキサイド、ポリエチレンイミン等の合成高分子物質や吸水性繊維等を挙げることができる。
【００４０】
【実施例】
以下、実施例および比較例により、本発明をさらに具体的に説明するが、本発明はこれらにより何ら限定されるものではない。なお、「部」は「重量部」を示す。
【００４１】
汚泥固化材は、高吸水性樹脂と、アルミン酸塩およびケイ酸塩の少なくとも一方とを含むものである。まず、上記高吸水性樹脂の各例を参考例１〜１０として次にそれぞれ説明する。
【００４２】
〔参考例１〕
温度計を備えた容量 2.5Ｌの卓上型ジャケット付ニーダー（内面は３フッ化エチレンでライニング処理）に43％メタクリル酸ナトリウム水溶液 581.4部（50重量％）およびメトキシポリエチレングリコール（ＥＯ付加モル数９）メタクリレート 250部（50重量％）、架橋剤としてポリエチレングリコール（ＥＯ付加モル数８）ジメタクリレート 2.6部（対単量体 0.2モル％）およびイオン交換水 164.8部を仕込んだ。
【００４３】
系内を窒素置換した後、ニーダーのブレードを回転させながらジャケットに40℃の温水を通水して内容物を40℃に昇温した（このとき、内容物中の単量体の濃度は50％である）。次いで、重合開始剤として、2,2'- アゾビス（2-アミジノプロパン）塩酸塩1.16部（対単量体0.15モル％）を添加して20秒間攪拌し溶解した後、攪拌を停止した。
【００４４】
直ちに重合が開始して 120分でピーク温度84℃に到達した。この間、ジャケット温度は内容物の温度と等しくなるように昇温した。次いで、ジャケット温度を80℃に調節して１時間熟成した。熟成終了後、回転数40rpm で10分間の解砕を行った。ニーダーを反転して、含水ゲルをニーダーの重合容器から取り出した。含水ゲルの重合容器への付着は全く認められなかった。
【００４５】
かくして得られた微細な含水ゲルを熱風循環式乾燥機で 120℃、４時間乾燥した。乾燥後、卓上簡易型粉砕機（共立理工（株）製）を用いて粉砕して高吸水性樹脂（１）を得た。高吸水性樹脂（１）における１％セメント水に対する吸水倍率を前記した方法により測定した結果、上記吸水倍率は３８ｇ／ｇであった。
【００４６】
〔参考例２〕
単量体組成として、メタクリル酸ナトリウム70重量％、メトキシポリエチレングリコール（ＥＯ付加モル数９）メタクリレート30重量％とし、かつ、単量体濃度を40重量％とした他は参考例１と同様にして高吸水性樹脂（２）を得た。高吸水性樹脂（２）の吸水倍率は、２２ｇ／ｇであった。
【００４７】
〔参考例３〕
単量体組成として、メトキシポリエチレングリコール（ＥＯ付加モル数９）メタクリレート 100重量％とし、かつ、単量体濃度を60重量％とした他は参考例１と同様にして高吸水性樹脂（３）を得た。高吸水性樹脂（３）の吸水倍率は、１６ｇ／ｇであった。
【００４８】
〔参考例４〕
単量体組成として、アクリル酸ナトリウム50重量％、ブトキシポリエチレングリコール（ＥＯ付加モル数50）アクリレート50重量％とした以外は実施例１と同様にして高吸水性樹脂（４）を得た。高吸水性樹脂（４）の吸水倍率は、２７ｇ／ｇであった。上記各高吸水性樹脂（１）〜（４）は請求項３記載の高吸水性樹脂に対応するものである。
【００４９】
〔参考例５〕
参考例１で用いたのと同じ重合容器に、37％アクリル酸ナトリウム水溶液 275.6部（30重量％）、40％アクリルアミド水溶液 595部（70重量％）および架橋剤としてＮ，Ｎ−メチレンビスアクリルアミド0.68部（対単量体 0.1モル％) およびイオン交換水 127.6部を仕込んだ。系内を窒素置換した後、ニーダーのブレードを回転（ 40rpm）させながらジャケットに20℃の温水を通水して内容物を20℃に昇温した（このとき、内容物中の単量体濃度は34重量％である）。
【００５０】
次いで、重合開始剤として、過硫酸ナトリウム1.55部、Ｌ−アスコルビン酸 0.155部を添加した。直ちに重合が開始して30分でピーク温度97℃に到達した。この間、ジャケット温度は内容物の温度と等しくなるように昇温した。次いで、ジャケット温度を80℃に調節して、30分間熟成した。
【００５１】
熟成終了後、上記回転数 40rpmで10分間の解砕を行い、ニーダーを反転して含水ゲルをニーダーの重合容器から取り出した。含水ゲルの重合容器への付着は全く認められなかった。
【００５２】
このように得られた微細な含水ゲルを熱風循環式乾燥機で 160℃、３時間乾燥した。乾燥後、卓上簡易型粉砕機（共立理工（株）製）を用いて粉砕して高吸水
性樹脂（５）を得た。高吸水性樹脂（５）の吸水倍率は、３３ｇ／ｇであった。
【００５３】
〔参考例６〕
単量体組成として、アクリル酸ナトリウム60重量％、アクリルアミド40重量％とした他は参考例５と同様にして高吸水性樹脂（６）を得た。高吸水性樹脂（６）の吸水倍率は、１８ｇ／ｇであった。
【００５４】
〔参考例７〕
単量体組成として、アクリルアミド 100重量％とした他は参考例５と同様にして高吸水性樹脂（７）を得た。高吸水性樹脂（７）の吸水倍率は、２１ｇ／ｇであった。上記各高吸水性樹脂（５）〜（７）は、請求項４記載の高吸水性樹脂に対応するものである。
【００５５】
〔参考例８〕
参考例１で用いたのと同じ重合容器に、43％メタクリル酸ナトリウム水溶液 372部（40重量％）、45％ソディウムスルホエチルメタクリレート水溶液 533.3部（60重量％）および架橋剤としてＮ，Ｎ−メチレンビスアクリルアミド0.40部（対単量体 0.1モル％) およびイオン交換水93.4部を仕込んだ。系内を窒素置換した後、ニーダーのブレードを回転（ 40rpm）させながらジャケットに50℃の温水を通水して内容物を50℃に昇温した（このとき、内容物中の単量体濃度は40重量％である）。
【００５６】
次いで、重合開始剤として、2,2'- アゾビス（N,N'- ジメチレンイソブチルアミジン）二塩酸塩0.39部および2,2'- アゾビス（2-アミジノプロパン）二塩酸塩0.52部を添加して20秒間攪拌し溶解した後、攪拌を停止した。
【００５７】
直ちに重合が開始して40分でピーク温度98℃に到達した。この間、ジャケット温度は内容物の温度と等しくなるように昇温した。次いで、ジャケット温度を80℃に調節して、30分間熟成した。
【００５８】
熟成終了後、上記回転数 40rpmで10分間の解砕を行い、ニーダーを反転して含水ゲルをニーダーの重合容器から取り出した。含水ゲルの重合容器への付着は全く認められなかった。
【００５９】
このように得られた微細な含水ゲルを熱風循環式乾燥機で 160℃、３時間乾燥した。乾燥後、卓上簡易型粉砕機（共立理工（株）製）を用いて粉砕して高吸水
性樹脂（８）を得た。高吸水性樹脂（８）の吸水倍率は、２７ｇ／ｇであった。
【００６０】
〔参考例９〕
単量体組成として、メタクリル酸ナトリウム80重量％、ソディウムスルホエチルメタクリレート20重量％とした他は参考例８と同様にして高吸水性樹脂（９）を得た。高吸水性樹脂（９）の吸水倍率は、１３ｇ／ｇであった。
【００６１】
〔参考例１０〕
単量体組成として、ソディウムスルホエチルメタクリレート 100重量％とした他は参考例８と同様にして高吸水性樹脂（１０）を得た。高吸水性樹脂（１０）の吸水倍率は、２５ｇ／ｇであった。上記各高吸水性樹脂（８）〜（１０）は請求項５記載の高吸水性樹脂に対応するものである。
【００６２】
〔実施例１〕
ベンナイト、セメント、水道水を含み、ベンナイト濃度６kg/m3 、セメント濃度250kg/m3の注入液を、ＳＭＷ（soil mixing wall) 工法により地下注入して排出されるセメント含有の汚泥1000部に対し、上記高吸水性樹脂（１）４部とアルミン酸ナトリウム（メタアルミン酸ナトリウム）１部を同時に添加して攪拌して混合した。
【００６３】
上記汚泥について、30分後の外観を肉眼で観察した結果、上記汚泥は、浮水、遊離水などの水分が全く認められず、弾力性を有する固体状態であった。さらに、この弾力性を有するが固体状態の汚泥 100部に対し２kg/cm2の荷重を印加し、その固化物からの離水量を測定した。その測定結果を表１に示した。さらに、この弾力性を有するが固体状態の汚泥を室温で２日間静置しておくと、汚泥中のセメントの作用により、高強度に固化していた。
【００６４】
〔実施例２〜３〕
実施例１におけるアルミン酸ナトリウムの使用量（部）を、実施例１に記載の１部に代えて、表１に示したように、４．０部、０．４部にそれぞれ使用量を変更した以外は、実施例１と同様の操作を行い、得られた汚泥の固化物における外観および離水量をそれぞれ測定した。その測定結果を表１に合わせて示した。
【００６５】
〔実施例４〕
実施例１におけるアルミン酸ナトリウムに代えてアルミン酸カリウムを使用した以外は、実施例１と同様の操作を行い、得られた汚泥の固化物における外観および離水量をそれぞれ測定した。その測定結果を表１に合わせて示した。
【００６６】
〔実施例５〕
実施例１と同じ汚泥1000部に対し、アルミン酸ナトリウム１部を添加して５分間攪拌して混合した後、実施例１と同様の高吸水性樹脂（１）４部を添加して攪拌して混合した。30分後の固化した汚泥の外観を肉眼で観察した結果、浮水、遊離水などの水分は全く認められず、上記汚泥は固体状態であった。
【００６７】
さらに、この固化物 100部に対し３kg/cm2の荷重を印加し、その固化物からの離水量を測定したところ、印加した荷重を実施例１と比べて増加させても離水量は０部であった。その測定結果を表１にも示した。
【００６８】
〔実施例６〜１４〕
実施例１における高吸水性樹脂（１）に代えて、参考例（２）〜（１０）の各高吸水性樹脂（２）〜（１０）をそれぞれ用いて、実施例１と同様の操作を行い、固化した汚泥について、その外観および離水量についてそれぞれ測定した。それらの測定結果を表１に合わせて示した。
【００６９】
〔実施例１５〜１９〕
実施例１における高吸水性樹脂（１）に代えて、市販の吸水性樹脂であるポリアクリル酸系吸水性樹脂（１％セメント水の吸水倍率、４ｇ／ｇ）、イソブチレン／マレイン酸系吸水性樹脂（１％セメント水の吸水倍率、２１ｇ／ｇ）、ビニルアルコール／アクリル酸系吸水性樹脂（１％セメント水の吸水倍率、１８ｇ／ｇ）、ポリビニルアセトアミド系吸水性樹脂（１％セメント水の吸水倍率、３３ｇ／ｇ）、ポリビニルアルコール系吸水性樹脂（１％セメント水の吸水倍率、１４ｇ／ｇ）をそれぞれ用いて、実施例１と同様の操作を行い、固化した汚泥について、その外観および離水量についてそれぞれ測定した。それらの測定結果を表１に合わせて示した。
【００７０】
【表１】

【００７１】
〔実施例２０〕
実施例１におけるアルミン酸ナトリウムに代えて、ケイ酸ナトリウム（メソ二ケイ酸ナトリウム、キシダ化学株式会社製）を、１部用いた以外は、実施例１と同様の操作を行い、得られた汚泥の固化物における外観および離水量をそれぞれ測定した。その測定結果を表２に示した。
【００７２】
〔実施例２１〕
実施例１におけるアルミン酸ナトリウムに代えて、ケイ酸ナトリウム（メソ二ケイ酸ナトリウム、キシダ化学株式会社製）を、４部用いた以外は、実施例１と同様の操作を行い、得られた汚泥の固化物における外観および離水量をそれぞれ測定した。その測定結果を表２に合わせて示した。
【００７３】
〔実施例２２〕
実施例１と同様な汚泥1000部に対し、ケイ酸ナトリウム３部を添加して５分間５分間攪拌して混合した後、実施例１と同様の高吸水性樹脂（１）１部を添加して攪拌して混合した。３０分後の固化した汚泥について、その外観および離水量についてそれぞれ測定した。その測定結果を表２に合わせて示した。
【００７４】
【表２】

【００７５】
次に、本願発明を説明するための各比較例１〜４について説明する。各比較例１〜４では、汚泥を固化させるための固化主剤として、参考例１に記載の高吸水性樹脂（１）、実施例１９記載のポリビニルアルコール系吸水性樹脂、およびグアーガムを用いた。
【００７６】
〔比較例１〕
実施例１におけるアルミン酸ナトリウムの添加を省いた他は実施例１と同様にして汚泥を固化させ、その固化した汚泥について、外観および離水量をそれぞれ測定した。それらの結果を表３に示した。
【００７７】
〔比較例２〕
比較例１における高吸水性樹脂（１）の使用量４．０部に代えて、上記高吸水性樹脂（１）を６．０部用いた他は比較例１と同様にアルミン酸ナトリウムの添加を省いて、汚泥を固化させた。その固化した汚泥について、外観および離水量をそれぞれ測定した。それらの結果を表３に合わせて示した。
【００７８】
〔比較例３〕
実施例１に記載の汚泥1000部に対し、高吸水性樹脂として、ポリビニルアルコール系高吸水性樹脂を４．０部と、酸性物質である硫酸アルミニウムを１．０部とを加えて、他は実施例１と同様に上記汚泥を固化させ、その固化した汚泥について、外観および離水量をそれぞれ測定した。それらの結果を表３に合わせて示した。
【００７９】
〔比較例４〕
実施例１に記載の汚泥1000部に対し、吸水性のものとして、グアーガムを４．０部と、添加剤としての塩化カルシウムを１．０部とを加えて、他は実施例１と同様に上記汚泥を固化させ、その固化した汚泥について、外観および離水量をそれぞれ測定した。それらの結果を表３に合わせて示した。
【００８０】
【表３】

【００８１】
本願発明に係る各実施例の構成は、表１および表２に示すように、外観において離水が観察されず固体状であり、加圧下での離水量も２部以下であった。一方、各比較例１〜４の各汚泥固化材では、離水が多く観察され、また、加圧下の離水量も２部を越えていた。
【００８２】
このように上記各実施例の構成では、高吸水性樹脂と、アルミン酸塩およびケイ酸塩の少なくとも一方とを用いることによって、汚泥が迅速に固化することから上記汚泥の取り扱いを容易化できると共に、固化した汚泥からの水分の離水を回避できるので、上記離水による周囲に対する汚れに起因する汚泥の処理時における周囲の環境の劣化や、流出した離水に対する処理の手間を防止できる。
【００８３】
その上、上記構成は、前記のＳＭＷ工法での排出汚泥のように、セメントを含有する汚泥に用いた場合においても、その固化処理を迅速化および確実化でき、かつ、固化した汚泥の固化強度が上記セメントにより経時的に向上することから、固化した汚泥による周囲への汚染をさらに確実に回避できるものとなっており、また、上記の汚泥を例えば埋め立てに用いたときに地盤沈下の恐れ等を回避できるといった顕著な効果を有するものとなっている。
【００８４】
本願発明の汚泥固化方法では、上述したように固化した汚泥から離水を抑制できて、固化した汚泥を取り扱い易いものとなっているが、さらに実施例５に示すように、まず、アルミン酸塩を加えた後に、高吸水性樹脂を添加・混合することにより、固化した汚泥からさらに離水を抑制、すなわち防止することができて、固化した汚泥の取り扱い易いをさらに容易とすることができる。
【００８５】
さらに、上記方法では、汚泥に対し、高吸水性樹脂、アルミン酸塩およびケイ酸塩の少なくとも一方と、セメントを混合することにより、上記汚泥における含水率が50重量％というように高含水率で、かつ、セメントの存在下に場合においても、汚泥を迅速に固化できると共に、そのように固化した汚泥の固化強度を上記セメントの固化により経時的にさらに高めることが可能となる。
【００８６】
よって、上記方法では、汚泥を廃棄処理する場合、高強度に固化した汚泥を、例えば埋め立て用として用いたときに、埋め立て地の地盤沈下の恐れを回避できると共に、汚泥に有害物質が含有しているときに、上記汚泥が地下水や雨水等と接触しても上記有害物質が固化した汚泥から溶出することを防止できるので、上記汚泥は廃棄処理の場所の適用範囲を拡大化でき、利用価値の高いものとなる。
【００８７】
【発明の効果】
本発明の汚泥固化材および汚泥固化方法は、高吸水性樹脂と、水溶性アルミン酸塩および水溶性ケイ酸塩の少なくとも一方とを汚泥固化材として含む構成であり、その汚泥固化材を汚泥に対し混合する方法である。
【００８８】
それゆえ、上記構成および方法は、高吸水性樹脂と、水溶性アルミン酸塩および水溶性ケイ酸塩の少なくとも一方とによって、汚泥が迅速に固化することから上記汚泥の取り扱いを容易化できると共に、固化した汚泥からの離水を抑制できるので、上記離水による周囲に対する汚れに起因する汚泥の処理時における周囲の環境の劣化や、流出した離水に対する処理の手間を軽減できるという効果を奏する。
【００８９】
本発明の他の汚泥固化方法は、汚泥に対し、高吸水性樹脂と、水溶性アルミン酸塩および水溶性ケイ酸塩の少なくとも一方と、セメントとを混合する方法である。
【００９０】
それゆえ、上記方法では、さらに、セメントを混合しても、水溶性アルミン酸塩および水溶性ケイ酸塩の少なくとも一方の混合によって、汚泥の固化が上記セメントの混合により阻害されることを回避できる。
【００９１】
このことから、上記方法では、汚泥の迅速な固化が維持されながら、固化した汚泥の強度を上記セメントにより、さらに経時的に改善できるという効果を奏する。[0001]
[Industrial application fields]
The present invention relates to a sludge solidifying material and a sludge solidifying method for making sludge generated after civil engineering work, dredging work, sewage treated by an activated sludge method, and the like into an easily disposable form.
[0002]
[Prior art]
Conventionally, sludge generated after civil engineering work, dredging work, and after treating sewage by the activated sludge method has been difficult to dispose of because it contains a lot of moisture and has a strange odor. Therefore, in order to solidify and stabilize the above-mentioned sludge containing a large amount of water to facilitate disposal, a method using a cement-based solidifying agent is considered, for example. However, such a method causes a problem that it takes about 24 to 72 hours for sludge to solidify and reach a certain strength that is easy to handle.
[0003]
Therefore, in order to avoid the above problems, (1) JP 54-112554 A discloses that a hydrophilic crosslinked polymer that swells by absorbing water is added to the mud. . (2) Japanese Patent Application Laid-Open No. 6-287556 discloses a soil solidifying agent composed of a superabsorbent resin, cement, and an acidic substance. (3) Japanese Examined Patent Publication No. 4-42080 discloses that sludge is mixed with an absorbent resin and a compound containing a divalent or higher cation, and then mixed with hydraulic cement. Yes.
[0004]
[Problems to be solved by the invention]
However, even if the sludge cannot be completely solidified or temporarily solidified by the configurations and methods of the above-mentioned conventional publications, the sludge solidified when transporting such solidified sludge for processing. Since some of the water contained in the water will be removed, the water will be contaminated by such water removal, and the surrounding environment will be deteriorated during the disposal of solidified sludge, etc. Is causing problems.
[0005]
[Means for Solving the Problems]
The sludge solidifying material of the present invention comprises a superabsorbent resin, Water soluble Aluminates and Water soluble It includes at least one of silicates.
[0006]
The sludge solidification method of the present invention is a highly water-absorbent resin for sludge, Water soluble Aluminates and Water soluble It is characterized in that at least one of silicates is added in combination.
[0007]
Another sludge solidification method of the present invention is a highly water-absorbent resin for sludge, Water soluble Aluminates and Water soluble It is characterized in that at least one of silicate and cement are added together.
[0008]
When cement is not used in combination, the solidified product is an elastic solid, but when cement is used in combination, a solidified product with higher strength can be obtained over time. In particular, high-strength solidified materials can avoid ground subsidence and fear when used for landfill, for example, and when harmful substances are contained in sludge, the above-mentioned harmful substances even if they come into contact with groundwater or rainwater Can be prevented from eluting from the solidified product. Therefore, the high-strength solidified product can expand the application range of the place of disposal.
[0009]
Examples of the aluminate include water-soluble aluminates such as sodium orthoaluminate, potassium orthoaluminate, lithium orthoaluminate, sodium metaaluminate, potassium metaaluminate, and lithium metaaluminate.
[0010]
Examples of silicates include sodium orthosilicate, potassium orthosilicate, lithium orthosilicate, sodium metabisilicate, potassium metabisilicate, lithium metabisilicate, sodium metatrisilicate, potassium metatrisilicate, meta Water-soluble silicates such as lithium silicate, sodium metatetrasilicate, potassium metatetrasilicate, and lithium metatetrasilicate can be mentioned.
[0011]
Examples of sludge include sludge generated during river and sea dredging work, sludge generated when sewage is treated by the activated sludge method, sludge discharged during civil engineering work, and various industrial wastes. It is done. In the present invention, for example, sludge discharged by a SMW (soil mixing wall) method or the like, particularly for sludge containing a large amount of polyvalent metal ions such as Al + 3, Ca + 2, and Fe + 3. Have
[0012]
Such an effect is considered to be because the adverse effect caused by the polyvalent metal ions on the solidification of sludge by the superabsorbent resin can be reduced by the addition of at least one of aluminate and silicate. The SMW method is a construction method for producing a partition wall underground by injecting a slurry containing cement and water, and optionally containing bennite into the underground.
[0013]
The superabsorbent resin and at least one of aluminate and silicate are blended with 100 parts by weight of superabsorbent resin and 10 to 300 parts by weight of at least one of aluminate and silicate. It is preferable.
[0014]
If the amount is less than 10 parts by weight, it may be difficult to sufficiently solidify the sludge, and water separation may be observed over time. When the blending amount exceeds 300 parts by weight, it is necessary to increase the amount of the superabsorbent resin in order to obtain a sludge solidified product having excellent stability over time.
[0015]
In the sludge solidification method of the present invention, it is particularly preferable to add a superabsorbent resin after adding at least one of aluminate and silicate to the sludge. In another sludge solidification method of the present invention, it is particularly preferable to add a superabsorbent resin and cement after adding at least one of aluminate and silicate to the sludge.
[0016]
The reason for adding at least one of the aluminate and silicate first is not clear but is presumed as follows. That is, it is considered that the polyvalent metal ions that adversely affect the solidification properties are first inactivated by adding at least one of aluminate and silicate to the sludge.
[0017]
The raw material monomer for obtaining the superabsorbent resin is not particularly limited, and a wide range of monomers can be used, for example, 1) acrylic acid, methacrylic acid, crotonic acid or their monovalent metals, Unsaturated monocarboxylic acid monomers such as partially neutralized products and completely neutralized products with divalent metals, ammonia and organic amines;
2) Unsaturated dicarboxylic acid monomers such as maleic acid, fumaric acid, itaconic acid, citraconic acid or partially neutralized or completely neutralized products of these monovalent metals, divalent metals, ammonia and organic amines;
3) Vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, 2-hydroxysulfopropyl (meth) ) Unsaturated sulfonic acid units such as acrylate, sulfoethylmaleimide, 3-allyloxy-2-hydroxypropane sulfonic acid or partially neutralized or completely neutralized by monovalent metal, divalent metal, ammonia or organic amine Mer;
4) Amide monomers such as (meth) acrylamide, vinylacetamide, isopropylacrylamide, t-butyl (meth) acrylamide;
5) Hydrophobic monomers such as (meth) acrylic acid ester, styrene, 2-methylstyrene, vinyl acetate;
6) 2-hydroxyethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, allyl alcohol, polyethylene glycol monoallyl ether, polypropylene glycol monoallyl ether, 3-methyl-2-butene- 1-ol (prenol), polyethylene glycol monoprenol ether, polypropylene glycol monoprenol ether, 2-methyl-3-buten-2-ol (isoprene alcohol), polyethylene glycol monoisoprene alcohol ether, polypropylene glycol monoisoprene alcohol ether , N-methylol (meth) acrylamide, glycerol mono (meth) acrylate, glycerol monoallyl ether, vinyl alcohol Hydroxyl group-containing unsaturated monomers such as
7) Cationic monomers such as dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylamide;
8) Nitrile monomers such as (meth) acrylonitrile;
9) Phosphorus monomers such as (meth) acrylamide methanephosphonic acid, (meth) acrylamide methanephosphonic acid methyl ester, 2- (meth) acrylamide-2-methylpropanephosphonic acid;
10) Nonionic monomers represented by the following general formula (1) can be exemplified.
[0018]
[Chemical 2]

[0019]
(However, R is hydrogen or a methyl group, X is a C2-C4 oxyalkylene group whose mole fraction of the oxyethylene group with respect to all the oxyalkylene groups is 50 mol% or more, and Y is C1-C1. An oxyalkylphenyl group having 1 to 3 alkoxy groups, a phenoxy group, or an alkyl group having 1 to 9 carbon atoms as a substituent, and n is a positive number from 3 to 100.)
Examples of the nonionic monomer represented by the general formula (1) include methoxypolyethylene glycol mono (meth) acrylate, methoxypolyethylene glycol / polypropylene glycol mono (meth) acrylate, methoxypolyethylene glycol / polybutylene glycol mono (meta) ) Acrylate, ethoxy polyethylene glycol mono (meth) acrylate, ethoxy polyethylene glycol / polypropylene glycol mono (meth) acrylate, ethoxy polyethylene glycol / polybutylene glycol mono (meth) acrylate, phenoxy polyethylene glycol mono (meth) acrylate, benzyloxypolyethylene glycol Mono (meth) acrylates can be mentioned, and one or more of these are used. Door can be.
[0020]
Among the monomers described above, it is preferable to use a nonionic monomer represented by the general formula (1), an amide group-containing monomer, and a sulfonic acid group-containing monomer.
[0021]
When the nonionic monomer represented by the general formula (1) is used, the monomer composition is 30 to 100% by weight of the nonionic monomer, and the monomer 70 to be copolymerizable with the nonionic monomer is 70 to It is preferably 0% by weight. As a preferable monomer copolymerizable with a nonionic monomer, the above-mentioned unsaturated monocarboxylic acid type monomer and unsaturated sulfonic acid type monomer can be mentioned.
[0022]
When using an amide group-containing monomer, the monomer composition should be 40 to 100% by weight of the amide group-containing monomer, and 60 to 0% by weight of the monomer copolymerizable with the amide group-containing monomer. Is preferred. Preferred monomers that can be copolymerized with the amide group-containing monomer include the aforementioned unsaturated monocarboxylic acid monomers and unsaturated sulfonic acid monomers.
[0023]
When the sulfonic acid group-containing monomer is used, the monomer composition is 20 to 100% by weight of the sulfonic acid group-containing monomer, and 80 to 0% by weight of the monomer copolymerizable with the sulfonic acid group-containing monomer. It is preferable that Preferred monomers that can be copolymerized with sulfonic acid group-containing monomers include the above-mentioned unsaturated monocarboxylic acid-based monomers and amide group-containing monomers.
Mention may be made of monomers and nonionic monomers represented by the general formula (1).
[0024]
The superabsorbent resin is usually obtained by polymerizing the monomer in the presence of 0.001 to 5 mol% of a crosslinking agent with respect to the monomer.
[0025]
Examples of the crosslinking agent include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and trimethylolpropane. There is no ethylenic property in one molecule such as tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol di (meth) acrylate, N, N-methylenebis (meth) acrylamide, triallyl isocyanurate, trimethylolpropane diallyl ether, etc. Compounds having two or more saturated groups; those having two or more functional groups that react with carboxyl groups in the monomer, such as ethylene glycol, diethylene glycol, Tylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, diethanolamine, triethanolamine, polypropylene glycol, pentaerythritol, sorbitol, sorbitan, glucose, mannitol, mannitan, sucrose and other polyhydric alcohols, ethylene glycol di Glycidyl ether, glycerin diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, Trimethylolpropane triglycidyl ether, glycerin tri Polyepoxy compounds and the like such as glycidyl ether, may be used those of one or more thereof.
[0026]
When a polyhydric alcohol is used as the crosslinking agent, it is preferably 150 to 250 ° C., and when a polyepoxy compound is used, it is preferably heat-treated during or after polymerization at 50 to 250 ° C.
[0027]
The amount of the crosslinking agent used is preferably 0.001 to 5 mol% with respect to the monomer. If the amount exceeds 5 mol%, the crosslink density of the resulting superabsorbent resin, which is a cross-linked polymer, becomes too high and the water absorption ability tends to decrease, resulting in poor solidification, but conversely 0.001 mol% If the amount is less than 1, the crosslinking density is too small and the initial absorption rate is significantly reduced, resulting in a decrease in solidification.
[0028]
As a polymerization method for obtaining a highly water-absorbent resin, conventionally known methods can be employed, and examples thereof include a method using a radical polymerization catalyst and a method of irradiating with radiation, electron beam, ultraviolet ray and the like. Examples of the radical polymerization catalyst include peroxides such as hydrogen peroxide, benzoyl peroxide and cumene hydroperoxide: azo compounds such as azobisisobutyronitrile and 2,2′-azobis-2-amidinopropane hydrochloride: Examples thereof include persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate. These polymerization initiators can be used in a mixture of two or more, and further used as a redox initiator by combining with a reducing agent such as sulfite, L-ascorbic acid, and ferric salt. Also good.
[0029]
Although the polymerization temperature varies depending on the type of catalyst used, the polymerization temperature is preferably in the range of 20 to 100 ° C. in order to sufficiently increase the molecular weight of the resulting superabsorbent resin and complete the polymerization.
[0030]
The monomer can be dissolved and diluted in a solvent and then used for polymerization. Examples of such a polymerization solvent include water, methanol, ethanol, acetone, dimethylformamide, and mixtures thereof, benzene, toluene. An organic solvent such as cyclohexane can be used.
[0031]
The solution concentration in the case of using a solvent solution with respect to the monomer is not particularly limited, but it is preferably 20% by weight to a saturation concentration or less in consideration of easy control of the polymerization reaction and yield and economy. .
[0032]
As the polymerization form, in addition to the solution polymerization method, for example, sorbitan fatty acid ester, sucrose fatty acid ester, glycerin fatty acid ester, polyglycerol fatty acid ester, cellulose ester such as ethyl cellulose, cellulose acetate, cellulose ether, α-olefin-maleic anhydride Reversed-phase suspension polymerization, cast polymerization, double-arm kneader shearing in which an aqueous monomer solution is dispersed in a hydrophobic organic solvent using a carboxyl group-containing polymer such as a copolymer as a dispersant Various methods such as a method of polymerizing a hydrogel polymer by force while being subdivided, a thin film polymerization method, and a spray polymerization method can be employed.
[0033]
The surface of the superabsorbent resin, which is a crosslinked polymer obtained as described above, is further crosslinked by a hydrophilic crosslinking agent, and a crosslinking density gradient is introduced between the vicinity of the surface and the inside thereof, thereby initial What increased the water absorption speed can also be used.
[0034]
Examples of such hydrophilic crosslinking agents include polyhydric alcohols such as glycerin, ethylene glycol, and pentaerythritol: polyepoxy compounds such as ethylene glycol diglycidyl ether: ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, Polyvalent amines such as pentaethylenehexamine and polyethyleneimine: Multivalent aldehydes such as glutaraldehyde and glyoxal: Multivalent metal salts such as aluminum chloride, magnesium chloride, calcium chloride, aluminum sulfate, magnesium sulfate, and calcium sulfate It is done.
[0035]
The amount of these hydrophilic crosslinking agents to be used is preferably in the range of 0.005 to 5% by weight with respect to the superabsorbent resin which is intended to crosslink the vicinity of the surface. In addition, there is no particular limitation on the method for crosslinking the vicinity of the surface of the superabsorbent resin, and a method of heating a hydrophilic crosslinker as it is or in the form of a solution after heating the superabsorbent resin powder, For example, a method in which a hydrophilic cross-linking agent is mixed with a dispersion obtained by dispersing a powder of a superabsorbent resin in a hydrophobic organic solvent and then heated as necessary can be employed.
[0036]
The particle diameter of the superabsorbent resin is not particularly limited, but a particle diameter of 10 to 1000 μm is usually used because it is easy to handle and industrially easily obtained. Although there is no restriction | limiting in particular about the water absorptivity of superabsorbent resin, What has a water absorption capacity | capacitance of 10 g / g or more by the following measuring method with respect to 1% cement water is preferable.
(Measurement method of water absorption magnification)
1 part by weight of Portland cement (manufactured by Tokuyama) was added to 99 parts by weight of deionized water, and the mixture was stirred for 2 hours to obtain a mixed solution. Then, the mixed solution was changed to No. It filtered with 2 filter papers, and the filtrate was made into 1% cement water.
[0037]
In the measurement of the water absorption ratio, first, about 0.1 g of a highly water-absorbing resin was weighed and added into a tea bag-like bag made of a material having water permeability such as nonwoven fabric, and then the bag was added with 100 g of the 1% cement water. After soaking for 24 hours, the weight of the bag was measured, and the water absorption ratio was calculated according to the following formula.
[0038]
Water absorption magnification (g / g) = (BC) / A
A: Weight of collected superabsorbent resin powder (g)
B: Total weight including bag after water absorption (g)
C: Weight including bag in blank test (g)
The sludge solidifying material of the present invention has strength when used alone, and a sludge solidified product with a small amount of water separation can be obtained. Of course, it can be used in combination with other solidifying materials as required.
[0039]
Other such solidifying materials include guar gum, locust bin gum, quince seed gum, arabinogalactan gum, gum arabic, tragacanth gum, starch, xanthan gum, gelatin coat, gelatin, sillyum gum, polysaccharides, alginates, carboxymethylcellulose, carboxymethyl Examples thereof include natural or semi-synthetic polymer materials such as hydroxyethyl cellulose, synthetic polymer materials such as polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, sodium polyacrylate, polyethylene oxide, and polyethyleneimine, and water-absorbing fibers.
[0040]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited at all by these. “Parts” indicates “parts by weight”.
[0041]
The sludge solidifying material contains a superabsorbent resin and at least one of aluminate and silicate. First, each example of the superabsorbent resin will be described as Reference Examples 1 to 10, respectively.
[0042]
[Reference Example 1]
A 2.5L desktop jacketed kneader equipped with a thermometer (the inner surface is lined with ethylene trifluoride), 431.4% aqueous solution of sodium methacrylate (581.4 parts, 50% by weight) and methoxypolyethylene glycol (9 addition moles of EO) 250 parts (50% by weight) of methacrylate, polyethylene glycol (EO addition mole number 8) 2.6 parts of dimethacrylate (0.2 mole% of monomer) and 164.8 parts of ion-exchanged water were charged as a crosslinking agent.
[0043]
After the inside of the system was purged with nitrogen, the contents were heated to 40 ° C. by passing warm water of 40 ° C. through the jacket while rotating the kneader blade (at this time, the monomer concentration in the contents was 50 %). Then, 1.16 parts of 2,2′-azobis (2-amidinopropane) hydrochloride (0.15 mol% based on monomer) was added as a polymerization initiator and stirred for 20 seconds to dissolve, then stirring was stopped.
[0044]
Polymerization started immediately, and a peak temperature of 84 ° C. was reached in 120 minutes. During this time, the jacket temperature was raised to be equal to the temperature of the contents. Next, the jacket temperature was adjusted to 80 ° C. and aged for 1 hour. After completion of aging, crushing was performed for 10 minutes at a rotation speed of 40 rpm. The kneader was inverted and the hydrogel was removed from the kneader polymerization vessel. No adhesion of the water-containing gel to the polymerization container was observed.
[0045]
The fine hydrous gel thus obtained was dried at 120 ° C. for 4 hours with a hot air circulating dryer. After drying, the mixture was pulverized using a tabletop simple pulverizer (manufactured by Kyoritsu Riko Co., Ltd.) to obtain a superabsorbent resin (1). As a result of measuring the water absorption rate with respect to 1% cement water in the superabsorbent resin (1) by the method described above, the water absorption rate was 38 g / g.
[0046]
[Reference Example 2]
The monomer composition was the same as in Reference Example 1 except that sodium methacrylate was 70% by weight, methoxypolyethylene glycol (9 addition moles of EO) methacrylate was 30% by weight, and the monomer concentration was 40% by weight. A highly water-absorbent resin (2) was obtained. The water absorption capacity of the highly water absorbent resin (2) was 22 g / g.
[0047]
[Reference Example 3]
The superabsorbent resin (3) was the same as in Reference Example 1 except that the monomer composition was 100% by weight of methoxypolyethylene glycol (EO added mole number 9) methacrylate and the monomer concentration was 60% by weight. Got. The water absorption rate of the highly water absorbent resin (3) was 16 g / g.
[0048]
[Reference Example 4]
A superabsorbent resin (4) was obtained in the same manner as in Example 1 except that the monomer composition was 50% by weight of sodium acrylate and 50% by weight of butoxypolyethylene glycol (50 moles of EO added) acrylate. The water absorption rate of the super absorbent resin (4) was 27 g / g. Each of the superabsorbent resins (1) to (4) corresponds to the superabsorbent resin according to claim 3.
[0049]
[Reference Example 5]
In the same polymerization vessel as used in Reference Example 1, 275.6 parts of a 37% sodium acrylate aqueous solution (30% by weight), 595 parts of a 40% aqueous acrylamide solution (70% by weight) and 0.68 N, N-methylenebisacrylamide as a crosslinking agent. Parts (0.1 mol% to monomer) and 127.6 parts of ion-exchanged water were charged. After the inside of the system was replaced with nitrogen, the temperature of the contents was raised to 20 ° C. by passing hot water of 20 ° C. through the jacket while rotating the kneader blade (40 rpm) (at this time, the monomer concentration in the contents) Is 34% by weight).
[0050]
Next, 1.55 parts of sodium persulfate and 0.155 parts of L-ascorbic acid were added as polymerization initiators. Polymerization started immediately and a peak temperature of 97 ° C. was reached in 30 minutes. During this time, the jacket temperature was raised to be equal to the temperature of the contents. Next, the jacket temperature was adjusted to 80 ° C. and aged for 30 minutes.
[0051]
After completion of aging, crushing was performed at the above rotation speed of 40 rpm for 10 minutes, the kneader was inverted, and the hydrated gel was taken out from the polymerization vessel of the kneader. No adhesion of the water-containing gel to the polymerization container was observed.
[0052]
The fine water-containing gel thus obtained was dried at 160 ° C. for 3 hours with a hot air circulation dryer. After drying, it is pulverized using a tabletop simple grinder (manufactured by Kyoritsu Riko Co., Ltd.) to absorb water.
Resin (5) was obtained. The water absorption rate of the highly water absorbent resin (5) was 33 g / g.
[0053]
[Reference Example 6]
A superabsorbent resin (6) was obtained in the same manner as in Reference Example 5 except that the monomer composition was 60% by weight of sodium acrylate and 40% by weight of acrylamide. The water absorption capacity of the highly water-absorbent resin (6) was 18 g / g.
[0054]
[Reference Example 7]
A superabsorbent resin (7) was obtained in the same manner as in Reference Example 5 except that the monomer composition was 100% by weight of acrylamide. The water absorption capacity of the superabsorbent resin (7) was 21 g / g. Each of the superabsorbent resins (5) to (7) corresponds to the superabsorbent resin according to claim 4.
[0055]
[Reference Example 8]
In the same polymerization vessel as that used in Reference Example 1, 372 parts (40% by weight) of 43% aqueous sodium methacrylate solution, 533.3 parts (60% by weight) of 45% sodium sulfoethyl methacrylate aqueous solution and N, N-methylene as a crosslinking agent 0.40 part of bisacrylamide (0.1 mol% to monomer) and 93.4 parts of ion-exchanged water were charged. After the inside of the system was purged with nitrogen, the temperature of the contents was raised to 50 ° C. by passing hot water of 50 ° C. through the jacket while rotating the kneader blade (40 rpm) (at this time, the monomer concentration in the contents) Is 40% by weight).
[0056]
Next, 0.32 part of 2,2'-azobis (N, N'-dimethyleneisobutylamidine) dihydrochloride and 0.52 part of 2,2'-azobis (2-amidinopropane) dihydrochloride were added as polymerization initiators. After stirring for 20 seconds to dissolve, stirring was stopped.
[0057]
Polymerization started immediately and a peak temperature of 98 ° C. was reached in 40 minutes. During this time, the jacket temperature was raised to be equal to the temperature of the contents. Next, the jacket temperature was adjusted to 80 ° C. and aged for 30 minutes.
[0058]
After completion of aging, crushing was performed at the above rotation speed of 40 rpm for 10 minutes, the kneader was inverted, and the hydrated gel was taken out from the polymerization vessel of the kneader. No adhesion of the water-containing gel to the polymerization container was observed.
[0059]
The fine water-containing gel thus obtained was dried at 160 ° C. for 3 hours with a hot air circulation dryer. After drying, it is pulverized using a tabletop simple grinder (manufactured by Kyoritsu Riko Co., Ltd.) to absorb water.
Resin (8) was obtained. The water absorption capacity of the super absorbent resin (8) was 27 g / g.
[0060]
[Reference Example 9]
A superabsorbent resin (9) was obtained in the same manner as in Reference Example 8 except that the monomer composition was 80% by weight of sodium methacrylate and 20% by weight of sodium sulfoethyl methacrylate. The water absorption capacity of the superabsorbent resin (9) was 13 g / g.
[0061]
[Reference Example 10]
A superabsorbent resin (10) was obtained in the same manner as in Reference Example 8 except that the monomer composition was 100% by weight of sodium sulfoethyl methacrylate. The water absorption rate of the highly water absorbent resin (10) was 25 g / g. Each of the superabsorbent resins (8) to (10) corresponds to the superabsorbent resin according to claim 5.
[0062]
[Example 1]
For 1000 parts of cement-containing sludge, which contains bennite, cement, and tap water, and is injected underground with a SMW (soil mixing wall) method with a bennite concentration of 6kg / m3 and cement concentration of 250kg / m3. 4 parts of the superabsorbent resin (1) and 1 part of sodium aluminate (sodium metaaluminate) were simultaneously added and stirred to mix.
[0063]
As a result of observing the appearance after 30 minutes with the naked eye, the sludge was in a solid state having no elasticity such as floating water and free water and having elasticity. Furthermore, a load of 2 kg / cm2 was applied to 100 parts of sludge having this elasticity but in a solid state, and the amount of water separation from the solidified product was measured. The measurement results are shown in Table 1. Furthermore, when this elastic sludge but solid sludge was allowed to stand at room temperature for 2 days, it was solidified with high strength by the action of cement in the sludge.
[0064]
[Examples 2-3]
The amount (parts) of sodium aluminate used in Example 1 was changed to 4.0 parts and 0.4 parts as shown in Table 1, instead of 1 part described in Example 1, respectively. Except having done, operation similar to Example 1 was performed, and the external appearance and water separation amount in the solidified material of the obtained sludge were measured, respectively. The measurement results are shown in Table 1.
[0065]
Example 4
Except that potassium aluminate was used instead of sodium aluminate in Example 1, the same operation as in Example 1 was performed, and the appearance and water separation amount in the solidified sludge obtained were measured. The measurement results are shown in Table 1.
[0066]
Example 5
To 1000 parts of the same sludge as in Example 1, 1 part of sodium aluminate was added and mixed by stirring for 5 minutes, and then 4 parts of the superabsorbent resin (1) similar to Example 1 was added and stirred. And mixed. As a result of visually observing the appearance of the solidified sludge after 30 minutes, no water such as floating water or free water was observed, and the sludge was in a solid state.
[0067]
Furthermore, when a load of 3 kg / cm 2 was applied to 100 parts of the solidified material and the amount of water separation from the solidified material was measured, the amount of water separation was 0 parts even if the applied load was increased compared to Example 1. there were. The measurement results are also shown in Table 1.
[0068]
[Examples 6 to 14]
Instead of the superabsorbent resin (1) in Example 1, the superabsorbent resins (2) to (10) of Reference Examples (2) to (10) were used, respectively, and the same operations as in Example 1 were performed. The sludge solidified was measured for its appearance and water separation. The measurement results are shown in Table 1.
[0069]
[Examples 15 to 19]
Instead of the highly water-absorbing resin (1) in Example 1, a commercially available water-absorbing polyacrylic acid-based water-absorbing resin (water absorption capacity of 1% cement water, 4 g / g), isobutylene / maleic acid-based water absorbing property Resin (water absorption capacity of 1% cement water, 21 g / g), vinyl alcohol / acrylic acid water absorption resin (water absorption capacity of 1% cement water, 18 g / g), polyvinyl acetamide water absorption resin (1% cement water Water absorption capacity, 33 g / g), polyvinyl alcohol-based water absorbent resin (water absorption capacity of 1% cement water, 14 g / g), the same operation as in Example 1 was carried out. The amount of water separation was measured for each. The measurement results are shown in Table 1.
[0070]
[Table 1]

[0071]
Example 20
Sludge obtained in the same manner as in Example 1 except that 1 part of sodium silicate (sodium mesodisilicate, manufactured by Kishida Chemical Co., Ltd.) was used instead of sodium aluminate in Example 1. The appearance and water separation amount of the solidified product were measured. The measurement results are shown in Table 2.
[0072]
Example 21
Sludge obtained in the same manner as in Example 1 except that 4 parts of sodium silicate (sodium mesosilicate, manufactured by Kishida Chemical Co., Ltd.) was used instead of sodium aluminate in Example 1. The appearance and water separation amount of the solidified product were measured. The measurement results are shown in Table 2.
[0073]
[Example 22]
To 1000 parts of sludge similar to Example 1, 3 parts of sodium silicate was added and mixed by stirring for 5 minutes and 5 minutes, and then 1 part of superabsorbent resin (1) similar to Example 1 was added. And stirred to mix. About the solidified sludge after 30 minutes, the external appearance and the amount of water separation were measured, respectively. The measurement results are shown in Table 2.
[0074]
[Table 2]

[0075]
Next, Comparative Examples 1 to 4 for explaining the present invention will be described. In each of Comparative Examples 1 to 4, the highly water-absorbent resin (1) described in Reference Example 1, the polyvinyl alcohol-based water-absorbent resin described in Example 19, and guar gum were used as solidification main agents for solidifying sludge.
[0076]
[Comparative Example 1]
Sludge was solidified in the same manner as in Example 1 except that the addition of sodium aluminate in Example 1 was omitted, and the appearance and water separation amount were measured for the solidified sludge. The results are shown in Table 3.
[0077]
[Comparative Example 2]
Addition of sodium aluminate as in Comparative Example 1 except that 6.0 parts of the superabsorbent resin (1) was used instead of 4.0 parts of the superabsorbent resin (1) in Comparative Example 1. The sludge was solidified. About the solidified sludge, the external appearance and the water separation amount were measured, respectively. The results are shown in Table 3.
[0078]
[Comparative Example 3]
For 1000 parts of sludge described in Example 1, 4.0 parts of polyvinyl alcohol-based superabsorbent resin and 1.0 part of aluminum sulfate, which is an acidic substance, are added as superabsorbent resins. The sludge was solidified in the same manner as in Example 1, and the appearance and water separation amount were measured for the solidified sludge. The results are shown in Table 3.
[0079]
[Comparative Example 4]
For the 1000 parts of sludge described in Example 1, 4.0 parts of guar gum and 1.0 part of calcium chloride as an additive were added as water-absorbing ones, and the others were the same as in Example 1. The sludge was solidified, and the appearance and water separation were measured for the solidified sludge. The results are shown in Table 3.
[0080]
[Table 3]

[0081]
As shown in Tables 1 and 2, the configuration of each example according to the present invention was solid with no water separation observed in appearance, and the amount of water separation under pressure was 2 parts or less. On the other hand, in each sludge solidification material of each comparative example 1-4, many water separation was observed, and the amount of water separation under pressure exceeded 2 parts.
[0082]
As described above, in the configuration of each of the above embodiments, the use of the superabsorbent resin and at least one of aluminate and silicate makes it possible to easily handle the sludge because the sludge is rapidly solidified. Since the water separation from the solidified sludge can be avoided, it is possible to prevent the surrounding environment from being deteriorated during the treatment of the sludge caused by the contamination of the surroundings due to the water separation and the trouble of the treatment for the outflow water separation.
[0083]
In addition, the above-described configuration can speed up and ensure the solidification treatment even when used for sludge containing cement, such as the discharged sludge in the SMW method, and the solidification strength of the solidified sludge. Is improved over time by the cement, so that contamination to the surroundings by solidified sludge can be more reliably avoided, and there is a risk of ground subsidence when the sludge is used for landfill, for example. It has a remarkable effect that can be avoided.
[0084]
In the sludge solidification method of the present invention, water separation can be suppressed from the solidified sludge as described above, and the solidified sludge is easy to handle, but as shown in Example 5, first, the aluminate is added. After the addition, by adding and mixing the superabsorbent resin, water separation can be further suppressed from the solidified sludge, that is, the solidified sludge can be easily handled.
[0085]
Furthermore, in the above method, by mixing cement with at least one of a superabsorbent resin, aluminate and silicate with respect to the sludge, the water content in the sludge is as high as 50% by weight. Even in the presence of cement, the sludge can be rapidly solidified, and the solidification strength of the solidified sludge can be further increased over time by the solidification of the cement.
[0086]
Therefore, in the above method, when the sludge is disposed of, when sludge solidified with high strength is used for, for example, landfill, the risk of land subsidence in the landfill can be avoided, and the sludge contains harmful substances. When the sludge is in contact with groundwater, rainwater, etc., the toxic substances can be prevented from leaching from the solidified sludge. It will be expensive.
[0087]
【The invention's effect】
The sludge solidifying material and the sludge solidifying method of the present invention include a superabsorbent resin, Water soluble Aluminates and Water soluble In this method, at least one of the silicates is included as a sludge solidifying material, and the sludge solidifying material is mixed with the sludge.
[0088]
Therefore, the above configuration and method include a superabsorbent resin, Water soluble Aluminates and Water soluble Since the sludge is solidified quickly by at least one of the silicates, the sludge can be easily handled and water separation from the solidified sludge can be suppressed. There is an effect that it is possible to reduce the trouble of the surrounding environment at the time and the time and effort of the treatment for the discharged water.
[0089]
Another sludge solidification method of the present invention is a highly water-absorbent resin for sludge, Water soluble Aluminates and Water soluble This is a method of mixing at least one of silicate and cement.
[0090]
Therefore, in the above method, even if cement is further mixed, Water soluble Aluminates and Water soluble By mixing at least one of the silicates, it is possible to prevent the solidification of the sludge from being inhibited by the mixing of the cement.
[0091]
For this reason, the above method has an effect that the strength of the solidified sludge can be further improved over time by the cement while maintaining the rapid solidification of the sludge.

Claims (9)

A sludge solidifying material comprising 10 to 300 parts by weight of at least one of a water-soluble aluminate and a water-soluble silicate with respect to 100 parts by weight of a superabsorbent resin.   The high water-absorbent resin is obtained by polymerizing a monomer in the presence of 0.001 to 5 mol% of a crosslinking agent with respect to the monomer. Sludge solidification material. Superabsorbent resin has the general formula (1)

(However, R is hydrogen or a methyl group, X is a C2-C4 oxyalkylene group whose mole fraction of the oxyethylene group with respect to all the oxyalkylene groups is 50 mol% or more, and Y is C1-C1. An oxyalkylphenyl group having 1 to 5 alkoxy groups, phenoxy groups, or 1 to 9 carbon atoms as a substituent, and n is a positive number from 3 to 100. The sludge solidifying material according to claim 1 or 2, which is a crosslinked polymer obtained by polymerizing a monomer component containing 30 to 100% by weight of a nonionic monomer.   The sludge solidifying material according to claim 1 or 2, wherein the superabsorbent resin is a crosslinked polymer obtained by polymerizing a monomer component containing 40 to 100% by weight of an amide group-containing monomer.   3. The sludge solidifying material according to claim 1, wherein the superabsorbent resin is a crosslinked polymer obtained by polymerizing a monomer component containing 20 to 100% by weight of a sulfonic acid group-containing monomer. . To the sludge, the superabsorbent polymer, the sludge solidification method for adding together and at least one water soluble aluminate and water soluble silicate, per 100 parts by weight of superabsorbent polymer, aluminates and silicates A method for solidifying sludge, wherein at least one of the salts is added in combination so as to be 10 to 300 parts by weight.   Furthermore, cement is added together, The sludge solidification method of Claim 6 characterized by the above-mentioned. The method for solidifying sludge according to claim 6, wherein at least one of a water-soluble aluminate and a water-soluble silicate is added to the sludge, and then a superabsorbent resin is added. The sludge solidification method according to claim 7, wherein at least one of a water-soluble aluminate and a water-soluble silicate is added to the sludge, and then a superabsorbent resin and cement are added.