JP2004249263A - Phosphorus recovering material and its production method - Google Patents
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Description
【０００１】
【発明の属する技術分野】本発明は、リン回収材およびその製造方法に関するものであり、更に詳しくは本発明は、リン回収性能が低下することなく常温養生時間を短くすることができ、大規模な造粒物貯蔵場所を必要としないばかりでなくリン回収材の製造工程中における移送による造粒物の崩壊が殆どない優れたリン回収材およびその製造方法に関するものである。
【０００２】
【従来の技術】従来、湖、沼、貯水池、河川水、生活排水、家畜屎尿排水、下水等からリン酸イオン態リンを効果的に除去する方法として、特にリン吸着材による脱リン処理は、管理者が常駐できない場合に有効な手段であり、しかも、凝集沈降分離のようなスラッジの回収処理を必要としない点で、近年注目されている。この吸着材（以下、脱リン材又はリン回収材のいずれかで呼ぶ。）としては、珪酸カルシウム水和物を主たる構成物とする脱リン材であって、この脱リン材は珪酸質原料からなる粉体と石灰質原料からなる粉体を用いて転動造粒し、造粒後、これを高温高圧養生して製造することが開示されている。この造粒物は、略球形状や中空パイプ状であって、全表面にアパタイトの析出サイトである珪酸カルシウム水和物が成長しており、この珪酸カルシウム水和物とリン含有水との接触面積が増大し、リンの吸着効率が極めて高くなっていることが示されている（例えば、特許文献１参照）。また石灰質原料と珪酸質原料とをオートクレーブ養生して得られた脱リン材と珪酸カルシウム水和物の常温硬化物とを組み合わせて用いて脱リンする方法が開示されている（例えば、特許文献２参照）。
【０００３】
【特許文献１】
特開平１０−２３５３４４号公報（段落００１６、段落００１７参照）
【特許文献２】
特開平１１−２１６３０２号公報（段落０００９、段落００１０参照）
【０００４】
【発明が解決しようとする課題】しかしながら、前述の公報に記載されているリン回収材は、石灰質原料と珪酸質原料とを混合した後、造粒し、常温養生し、更にオートクレーブ養生してリン回収材を製造するが、造粒後の工程として、常温養生１８時間以上を必要とするため、これらの工程中、特に常温養生において造粒物の破壊が大きく、またオートクレーブ養生するために移送するなどで造粒物が破壊されたりし、製品の歩留まりが低下るという問題があった。
【０００５】
そこで、本発明者等は、上記問題点につき種々検討し、造粒物の硬化を促進させるために速硬性材料を添加してみたところ、硬化が促進され、常温養生時間を短縮することができるばかりでなくリン回収材の構成成分であるトバモライトの生成を阻害することなく、むしろその生成を促進することができることを見出し、この知見に基づいて本発明はなされたものである。したがって、本発明が解決しようとする第１の課題は、リン回収性能が増大し、造粒物の崩壊が殆どない優れたリン回収材を提供することにある。本発明が解決しようとする第２の課題は、常温養生時間を短くすることができるばかりでなくリン回収性能が増大することができ、大規模な造粒物貯蔵場所を必要としないと共にリン回収材の製造工程中における移送による造粒物の崩壊が殆どない優れたリン回収材の製造方法を提供することにある。
【０００６】
【課題を解決するための手段】本発明の上記の各課題は、以下の各発明によってそれぞれ達成される。
（１）石灰質原料、珪酸質原料および速硬性材料の造粒物であって、該造粒物は常温養生およびオートクレーブ養生がなされていることを特徴とするリン回収材。
（２）速硬性材料がアルミナセメント、消石灰および石膏からなることを特徴とする前記第１項に記載のリン回収材。
（３）速硬性材料の組成がアルミナセメント４０〜６０重量％、消石灰３０〜５重量％、石膏３０〜３５重量％であることを特徴とする前記第１項又は第２項に記載のリン回収材。
（４）石灰質原料と珪酸質原料の全体に対する速硬性材料の添加割合は、１０〜４０重量％であることを特徴とする前記第１項乃至第３項のいずれかに記載のリン回収材。
（５）造粒物のカルシウム分（ＣａＯ）とシリカ分（ＳｉＯ２ ）がＣａＯ／ＳｉＯ２ のモル比で０．５〜１．０であることを特徴とする前記第１項乃至第４項のいずれかに記載のリン回収材。
（６）石灰質原料、珪酸質原料および速硬性材料を混合した後、造粒し、ついで１５分〜１時間常温養生した後、オートクレーブ養生することを特徴とする前記第１項乃至第５項のいずれかに記載のリン回収材の製造方法。
【０００７】
前記第１項に記載の発明のリン回収材は、石灰質原料、珪酸質原料および速硬性材料の造粒物であって、該造粒物は常温養生およびオートクレーブ養生がなされていることを特徴とするもので、速硬性材料を添加した造粒物が常温養生およびオートクレーブ養生されていることにより、りん回収材に悪影響を与えないばかりか、むしろ、リン回収性能が増大し、造粒物の崩壊が殆どないという優れた効果を奏すると共に、常温養生時間を短くすることができ、大規模な造粒物貯蔵場所を必要としないという優れた効果を奏するものである。また前記第２項に記載の発明のリン回収材は、前記第１項の記載において、速硬性材料がアルミナセメント、消石灰および石膏からなることにより、リン回収性能が増大し、造粒物の崩壊が殆どないという優れた硬化造粒物が得られるという効果を奏するものである。
【０００８】
前記第３項に記載の発明のリン回収材は、前記第１項又は第２項において、速硬性材料の組成がアルミナセメント４０〜６０重量％、消石灰３０〜５重量％、石膏３０〜３５重量％であることにより、リン回収性能がいっそう増大し、造粒物の崩壊が殆どないといういっそう優れた硬化造粒物が得られるという効果を奏するものである。前記第４項に記載の発明のリン回収材は、前記第１項乃至第３項のいずれかの記載において、石灰質原料と珪酸質原料の全体に対する速硬性材料の添加割合は、１０〜４０重量％であることにより、常温養生時間を短縮することができると共に、リン回収性能がいっそう増大し、造粒物の崩壊が殆どないという優れた効果を奏するものである。更に前記第５項に記載の発明のリン回収材は、前記第１項乃至第４項のいずれかの記載において、造粒物のカルシウム分（ＣａＯ）とシリカ分（ＳｉＯ２ ）がＣａＯ／ＳｉＯ２ のモル比で０．５〜１．０であることにより、リン回収性能がいっそう増大し、造粒物の崩壊が殆どないという優れた効果を奏するものである。
【０００９】
前記第６項に記載の発明のリン回収材の製造方法は、前記第１項乃至第５項のいずれかの記載において、石灰質原料、珪酸質原料および速硬性材料を混合した後、造粒し、ついで１５分〜１時間常温養生した後、オートクレーブ養生することを特徴とするもので、速硬性材料を混合したことにより常温養生時間を１５分〜１時間とすることができると共に、リン回収性能が増大することができ、大規模な造粒物貯蔵場所を必要としないばかりでなくリン回収材の製造工程中における移送による造粒物の崩壊が殆どないという優れた効果を奏するものである。
【００１０】
【発明の実施の形態】以下に、本発明の実施の形態を説明するが、本発明は、これのみによって限定されるものではない。
【００１１】
本発明のりん回収材は、石灰質原料、珪酸質原料および速硬性材料の造粒物であって、該造粒物は常温養生およびオートクレーブ養生がなされていることを特徴とするものであり、石灰質原料は、通常、りん回収材を構成する成分を含むが、セメント、生石灰などが好適である。また同様に珪酸質原料としては、好ましくは珪石、珪藻土、珪酸白土、高炉スラグ、フライアッシュ等が挙げられる。また速硬性材料は、前記の石灰質原料と珪酸質原料からなる造粒物の常温養生時間を短縮するために添加されるものであり、この速硬性材料を添加することにより常温養生時間が１５分〜１時間に短縮される。したがって、本発明のりん回収材は、石灰質原料、珪酸質原料および速硬性材料の造粒物であって、該造粒物は１５分〜１時間の常温養生およびオートクレーブ養生がなされているものである。通常のりん回収材は、石灰質原料と珪酸質原料を主成分とするものであるが、本発明では、石灰質原料と珪酸質原料を主成分とするりん回収材に速硬性材料を添加したもので、速硬性材料としては、アルミナセメント、消石灰および石膏を混合したものが好ましいが、これに限定されるものではない。本発明において、石灰質原料、珪酸質原料及び速硬性材料からなる混合物は、造粒された後、常温養生されるが、この常温養生時間は、好ましくは１５分〜１時間である。
【００１２】
本発明に用いられる速硬性材料の組成はアルミナセメント４０〜６０重量％、消石灰３０〜５重量％、石膏３０〜３５重量％の範囲で特に好ましい効果、即ちりん回収性能の向上及び造粒物が短時間で硬化する等の効果を奏するものである。更に本発明のリン回収材は、石灰質原料と珪酸質原料の全体に対する速硬性材料の添加割合は、１０〜４０重量％である。好ましくはこの割合は、２０〜４０重量％である。速硬性材料の添加割合が、１０重量％未満のときは、短時間常温養生では造粒物の崩壊率が多く、したがって造粒物の収率が十分とは言えない。また速硬性材料の添加割合が、４０重量％を越えると、トバモライトが生成しないばかりか造粒物の崩壊率は少なくなるが、造粒物の収率が極めて少なくなる。
【００１３】
本発明に用いられる造粒物のカルシウム分（ＣａＯ）とシリカ分（ＳｉＯ２ ）がＣａＯ／ＳｉＯ２ のモル比で０．５〜１．０であるときに特に好ましい効果を奏する。
【００１４】
本発明において、前記の第１項乃至第５項のいずれかに記載のリン回収材の製造方法は、石灰質原料、珪酸質原料および速硬性材料を混合した後、造粒し、ついで１５分〜１時間常温養生した後、オートクレーブ養生することを特徴とするものである。造粒して得られる造粒物は、任意の形状でよいが、好ましくは略球形状又は中空パイプ状に形成されている。この中空パイプ状とは、断面円形の環状に限らず、各断面が楕円形、三角形、四角形、五角形などの多角形状、または、任意形の環状でもよい。本発明に用いられる脱リン材の大きさは、特に限定されるものではないが、略球形状の場合には直径が１〜１５ｍｍ程度の球体とするのがよい。また押し出し成形の場合、例えば外径３〜２０ｍｍ、内径１〜１５ｍｍ、長さ０．１〜２ｍ程度の中空パイプとするのがよい。
【００１５】
本発明に用いられる造粒物は、湿空中（相対湿度８０％以上）にて養生する工程と、この後、オートクレーブ養生する工程とを備えており、まず珪酸質原料からなる粉体および石灰質原料からなる粉体とを混合し混合材料を軟化する工程と、軟化した混合材料を略球状に形成するか又は中空パイプ状に押し出し成形する工程と、得られた成形物を高温高圧養生することにより製造する。粉体の押し出し成形には、周知の押し出し成形機を使用することができる。本発明の製造方法において、石灰質原料と珪酸質原料と速硬性材料との混合物からなる造粒物は、常温養生及び高温高圧養生により硬化させると珪酸カルシウム水和物が得られる。この珪酸カルシウム水和物は、主としてトバモライトであるが、トバモライト、ゾノトライト、ヒレブランダイトの中の１種類または２種類以上の組み合わせであってもよい。
【００１６】
本発明に用いられる造粒物は、常温養生により１５分〜１時間で硬化する。常温養生時間が、１５分未満のときは、２０％以上の崩壊率となり本発明の目的外となる。また常温養生時間が１時間を越える場合には、十分の硬化が得られ、それ以上の常温養生時間は必要でない。更に本発明の製造方法では、常温養生した後、オートクレーブ養生（高温高圧養生）を行う。このオートクレーブ養生は通常、気圧１０〜１５ａｔｍ、温度１８０〜２００℃で２時間〜１０時間が費やされる。したがって、従来のりん回収材の製造方法では、常温養生時間とオートクレーブ養生時間とを合わせると、約２６時間という長時間を要するが、本発明のりん回収材の製造方法では、常温養生時間１５分〜１時間であり、オートクレーブ養生は約８時間としても合わせて８時間１５分〜９時間であり、即ち１０時間以下となり、全体的に極めて短時間で養生することができ、しかも常温養生が短時間でも造粒物の崩壊率は、通常の場合と殆ど変わらないものが得られるばかりでなくりん回収性能も向上する。
【００１７】
【実施例】以下、本発明を実施例を挙げて説明するが、本発明は、これらに限定されるものではない。
【００１８】
〔参考例〕速硬性材料の製造 アルミナセメント６０重量部、無水石こう３０重量部、消石灰１０重量部を混合して、速硬性材料を製造した。ついで普通ポルトランドセメント、珪石粉末及び上記で製造した速硬性材料を混合した後、造粒した。造粒にはパン型ペレタイザーを用いて行った。その際、普通ポルトランドセメントと珪石粉末の配合割合は、アルミナセメント、無水石こう及び消石灰を含む全ての原料中のＣａＯ分とＳｉＯ２ 分とから、ＣａＯ／ＳｉＯ２ のモル比が０．７５になるように設定した。珪石粉末は、純度９３％、ブレーン法で粉末度３５００ｇ／ｍ３ のものを用いた。上記で得られた造粒物を温度２０℃で１８時間常温養生を行い、その後水中に浸漬し、水切り後オートクレーブ養生を気圧１０ａｔｍ、１８０℃で８時間行ってりん回収材を得た。
【００１９】
〔実施例１〕 普通ポルトランドセメントと珪石粉末に、参考例で製造した速硬性材料５重量部〜５０重量部を表１に示される量、それぞれ添加した後、混合を行い、パン型ペレタイザーを用いて造粒した。珪石粉末及び普通ポルトランドセメントの量は、モル比が０．７５となるように設定した。即ち、普通ポルトランドセメント、珪石粉末及び速硬性材料の量は、表１の如くである。得られた造粒物を温度２０℃で１８時間常温養生を行い、その後水中に浸漬し、水切り後オートクレーブ養生を気圧１０ａｔｍ、１８０℃で８時間行ってりん回収材（以下、製品という。）を得た。その際、造粒物の収率とオートクレーブ養生で得られた製品について、単位容積質量、ｐＨ値、Ｘ線回折により反応生成物を同定した。それらの結果から、速硬性材料の無添加時の製品と添加時の製品の性状を比較した。試験結果を表１に示す。なお、「水切り」とは、水中浸漬後、水中から取り出した状態で、材料内部は水を保ち、表面には若干水分がある状態をいう。
【００２０】
【表１】
２）製品（粒径１．０〜１．７ｍｍ）を１Ｌ容器に充填した後の質量
３）試料１ｇを水道水１００ｍＬに１時間浸漬した時のｐＨ値
４）粉末Ｘ線回折法による生成物の確認
Ｔｏ：トバモライト（５ＣａＯ・６ＳｉＯ２ ・５Ｈ２ Ｏ）
ＣＳ：ＩＩ型無水石こう（ＣａＳＯ４ ）
ＣＳＨ：ＣＳＨＧｅｌ（ＣａＯ・ＳｉＯ２ ・Ｈ２ Ｏ）
ＨＧ：ハイドロガーネット（３ＣａＯ・Ａｌ２ Ｏ３ ・６Ｈ２ Ｏ）
５）原料がパン型ペレタイザー内で硬化し、造粒物が球状にならず、肥大化する。
【００２１】
表１から明らかなように、造粒物の収率は、速硬性材料は４０％まで添加することによって向上する。製品の単位容積質量は、速硬性材料を添加してもほとんど変わらない。また製品のｐＨ値は、速硬性材料を添加すると低くなる。更にＸ線回折によると、速硬性材料の添加率４０％までは、無添加の製品と同様にトバモライトが生成することがわかる。
【００２２】
〔実施例２〕 普通ポルトランドセメントと珪石粉末に速硬性材料５重量部〜５０重量部添加した後、混合を行い、実施例１の表１に示される組成の造粒物をパン型ペレタイザーを用いて造粒した。得られた造粒物の常温養生時間を１５分、３０分、１時間及び１８時間とし、各養生時間後の造粒物について水中浸漬時の崩壊率を測定した。崩壊率は、造粒物（粒径１．０〜１．７ｍｍ）２００ｇを１．０ｍｍ篩に入れ、その篩を水中に浸漬する。約１分後、篩を軽く揺すった後、水中から引上げ、篩残分をバットに移し、乾燥後の重量を測定する。最初の重量と乾燥後の重量との差を取り、これを最初の重量で割って崩壊率を算出する。得られた結果を表２に示す。
【００２３】
【表２】
表２から明らかなように、製品は、速硬性材料を１０％添加することによって、常温養生時間１５分で崩壊率２０％になった。また速硬性材料を２０％〜４０％添加することで、常温養生時間を１５分における崩壊率が無添加の製品の常温養生時間１８時間の場合と同程度となった。したがって、速硬性材料を添加することによって、常温養生時間を大幅に短縮することができた。
【００２５】
〔実施例３〕 速硬性材料を表３に示す混合割合で製造し、これらの速硬性材料を普通ポルトランドセメントと珪石粉末にそれぞれ１０重量部添加した後、混合し、パン型ペレタイザーを用いて造粒した。その際、ＣａＯ／ＳｉＯ２ のモル比が０．７５になるように普通ポルトランドセメントと珪石粉末の配合割合を調整した。この時の普通ポルトランドセメントの量は、４８重量部であり、珪石粉末の量は、４２重量部である。得られた造粒物の常温養生時間を１５分とし、水中浸漬時の崩壊率を測定した。得られた結果を表３に示す。
【００２６】
【表３】
表３から明らかなように、速硬性材料における無水石こうの添加率を一定にして消石灰の添加率を増加させると、添加率２０％で崩壊率が最低となった。
【００２８】
〔実施例４〕アルミナセメント６０重量部、無水石膏３０重量部及び消石灰１０重量部を混合して速硬性材料を作製した。この速硬性材料を普通ポルトランドセメントと珪石粉末に１０重量部添加した後、混合し、製造用原料とした。その際、表４に示すようにＣａＯ／ＳｉＯ２ のモル比が０．４〜１．２まで変化させてりん回収材を製造した。造粒後の常温養生時間を１５分とし、水中浸漬時の崩壊率を測定した。またオートクレーブ養生後の製品について、小型カラムを用いた室内試験でりん回収率を測定した。得られた結果を表４に示す。
【００２９】
〔りん回収率の測定方法〕
１．試験方法 原水には、りん酸二水素カリウム（試験、ＫＨ２ ＰＯ４ ）、水酸化ナトリウム（試薬、ＮａＯＨ）及び水道水を用いてＰＯ４ ・Ｐ＊：５０ｍｇ／Ｌに調整した模擬汚水を使用した。かさ容積１５０ｍＬのりん回収材をカラムに充填し、原水を１５０ｍＬ／ｈの流速（ＳＶ＝１ｈｒ−１）で連続通水し、７日後の処理水の水質を分析した。また反応部の循環速度をりん回収材の膨張率が約２０〜２５％となるように随時調整した。分析項目は、溶液中に溶解しているりん分（ＰＯ４ ・Ｐ）および浮遊物質（ここではりんを含む凝集沈澱物：ＳＳ）の量とした。
【００３０】
２．りん回収率の定義
（１）ＰＯ４ ・Ｐ除去率（％）
＝（原水ＰＯ４ ・Ｐ濃度−処理水ＰＯ４ ・Ｐ濃度）／原水ＰＯ４ ・Ｐ濃度×１００
（２）凝集沈澱率（５）
＝〔（洗浄水全りん濃度１）−洗浄水ＰＯ４ ・Ｐ濃度）×洗浄水量〕／
（原水ＰＯ４ ・Ｐ濃度×原水通水量）×１００
１）全りん濃度：ＳＳ中のＰ濃度＋ＰＯ４ ・Ｐ濃度
（３）りん回収率（％）＝ＰＯ４ ・Ｐ除去率−凝集沈澱率
【００３１】
【表４】
表４から明らかなように、試料Ｎｏ．１２の比較例では、崩壊率が高く、またりん回収率も低い。試料Ｎｏ．１７の比較例では、崩壊率は悪くないが、小型カラム実験では、凝集沈澱を起こし、りん回収材にりんが晶析されず、したがってりん回収率が低いことがわかる。
【００３３】
【発明の効果】本願発明の請求項１に記載の発明のリン回収材は、石灰質原料、珪酸質原料および速硬性材料の造粒物であって、該造粒物は常温養生およびオートクレーブ養生がなされていることにより、速硬性材料を添加した造粒物が常温養生およびオートクレーブ養生されていることにより、りん回収材に悪影響を与えないばかりか、むしろ、リン回収性能が増大し、造粒物の崩壊が殆どないという優れた効果を奏すると共に、常温養生時間を短くすることができ、大規模な造粒物貯蔵場所を必要としないという優れた効果を奏するものである。また請求項２に記載の発明のリン回収材は、前記請求項１の記載において、速硬性材料がアルミナセメント、消石灰および石膏からなることにより、リン回収性能が増大し、造粒物の崩壊が殆どないという優れた硬化造粒物が得られるという効果を奏するものである。
【００３４】
本願発明の請求項３に記載の発明のリン回収材は、請求項１又は請求項２において、速硬性材料の組成がアルミナセメント４０〜６０重量％、消石灰３０〜５重量％、石膏３０〜３５重量％であることにより、リン回収性能がいっそう増大し、造粒物の崩壊が殆どないといういっそう優れた硬化造粒物が得られるという効果を奏するものである。本願発明の請求項４に記載の発明のリン回収材は、請求項１乃至請求項３のいずれかの記載において、石灰質原料と珪酸質原料の全体に対する速硬性材料の添加割合は、１０〜４０重量％であることにより、常温養生時間を短縮することができると共に、リン回収性能がいっそう増大し、造粒物の崩壊が殆どないという優れた効果を奏するものである。更に本願発明の請求項５に記載の発明のリン回収材は、請求項１乃至請求項４のいずれかの記載において、造粒物のカルシウム分（ＣａＯ）とシリカ分（ＳｉＯ２ ）がＣａＯ／ＳｉＯ２ のモル比で０．５〜１．０であることにより、リン回収性能がいっそう増大し、造粒物の崩壊が殆どないという優れた効果を奏するものである。
【００３５】
本願発明の請求項６に記載の発明のリン回収材の製造方法は、請求項１乃至請求項５のいずれかの記載において、石灰質原料、珪酸質原料および速硬性材料を混合した後、造粒し、ついで１５分〜１時間常温養生した後、オートクレーブ養生することを特徴とするもので、速硬性材料を混合したことにより常温養生機関を１５分〜１時間とすることができると共に、リン回収性能が増大することができ、大規模な造粒物貯蔵場所を必要としないばかりでなくリン回収材の製造工程中における移送による造粒物の崩壊が殆どないという優れた効果を奏するものである。[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphorus recovery material and a method for producing the same, and more particularly, the present invention can reduce the room temperature curing time without deteriorating the phosphorus recovery performance, and TECHNICAL FIELD The present invention relates to an excellent phosphorus recovery material which does not require a storage place for granulated materials and hardly disintegrates granules due to transportation during the manufacturing process of the phosphorus recovery material, and a method for producing the same.
[0002]
2. Description of the Related Art Conventionally, as a method for effectively removing phosphate ion form phosphorus from lakes, swamps, reservoirs, river water, domestic wastewater, livestock wastewater, sewage, etc., a phosphorus removal treatment using a phosphorus adsorbent, In recent years, it has been attracting attention because it is an effective means when a manager cannot be stationed, and does not require sludge recovery treatment such as coagulation and sedimentation. The adsorbent (hereinafter, referred to as either a dephosphorizing material or a phosphorus collecting material) is a dephosphorizing material having calcium silicate hydrate as a main component, and the dephosphorizing material is obtained from a siliceous raw material. It is disclosed that tumbling granulation is carried out using a powder made of a powder of lime and a calcareous raw material, and after granulation, this is cured by high temperature and pressure. This granulated product has a substantially spherical shape or a hollow pipe shape, and calcium silicate hydrate, which is a precipitation site of apatite, is grown on the entire surface, and the contact between the calcium silicate hydrate and the phosphorus-containing water is performed. It is shown that the area is increased and the phosphorus adsorption efficiency is extremely high (for example, see Patent Document 1). Further, there is disclosed a method of dephosphorization using a combination of a dephosphorizing material obtained by autoclaving a calcareous raw material and a siliceous raw material and a cold cured product of calcium silicate hydrate (for example, Patent Document 2). reference).
[0003]
[Patent Document 1]
JP-A-10-235344 (see paragraphs 0016 and 0017)
[Patent Document 2]
JP-A-11-216302 (see paragraphs 0009 and 0010)
[0004]
However, the phosphorus recovering material described in the above-mentioned publication is obtained by mixing a calcareous raw material and a siliceous raw material, granulating the mixture, curing the mixture at room temperature, and curing it in an autoclave. Although the recovered material is manufactured, since a normal temperature curing of 18 hours or more is required as a process after granulation, the granulated material is largely destroyed during these processes, particularly at normal temperature curing, and is transferred for autoclave curing. For example, there is a problem that the granules are destroyed due to the above-mentioned factors, and the yield of products is reduced.
[0005]
Therefore, the present inventors have variously examined the above problems, and when adding a quick-setting material to promote the hardening of the granulated material, the hardening is promoted and the room temperature curing time can be shortened. In addition, they have found that the production of tobermorite, which is a component of the phosphorus recovery material, can be promoted without inhibiting the production, and the present invention has been made based on this finding. Therefore, a first problem to be solved by the present invention is to provide an excellent phosphorus recovery material with increased phosphorus recovery performance and little collapse of granules. A second problem to be solved by the present invention is that not only the room temperature curing time can be shortened, but also the phosphorus recovery performance can be increased, so that a large-scale granule storage place is not required and the phosphorus recovery is not required. An object of the present invention is to provide an excellent method for producing a phosphorus recovery material, which hardly disintegrates granules due to transfer during the production process of the material.
[0006]
The above objects of the present invention are achieved by the following inventions.
(1) A phosphorus recovery material which is a granulated product of a calcareous raw material, a siliceous raw material, and a fast-setting material, wherein the granulated material has been subjected to room temperature curing and autoclave curing.
(2) The phosphorus recovery material as described in (1) above, wherein the quick-setting material is made of alumina cement, slaked lime and gypsum.
(3) The phosphorus recovery according to the above (1) or (2), wherein the composition of the quick-setting material is 40 to 60% by weight of alumina cement, 30 to 5% by weight of slaked lime, and 30 to 35% by weight of gypsum. Wood.
(4) The phosphorus recovery material according to any one of (1) to (3) above, wherein the addition ratio of the quick-hardening material to the whole of the calcareous raw material and the siliceous raw material is 10 to 40% by weight.
(5) The above-mentioned items 1 to 4, wherein the calcium content (CaO) and the silica content (SiO 2 ) of the granulated product are 0.5 to 1.0 in a molar ratio of CaO / SiO 2. The phosphorus recovery material according to any one of the above.
(6) The method according to any one of (1) to (5) above, wherein the calcareous raw material, the siliceous raw material, and the quick-setting material are mixed, granulated, then cured at room temperature for 15 minutes to 1 hour, and then autoclaved. A method for producing a phosphorus recovery material according to any one of the above.
[0007]
The phosphorus recovery material according to the first aspect of the present invention is a granulated product of a calcareous raw material, a siliceous raw material, and a fast-setting material, wherein the granulated material is subjected to room temperature curing and autoclave curing. Since the granulated material to which the fast-setting material is added has been cured at room temperature and in an autoclave, not only does it have no adverse effect on the phosphorus recovery material, but also the phosphorus recovery performance increases, and the granulated material disintegrates. In addition to the excellent effect that there is little, the room temperature curing time can be shortened, and the excellent effect that a large-scale granule storage place is not required is exhibited. Further, in the phosphorus recovery material according to the second aspect, in the first aspect, the quick-setting material is made of alumina cement, slaked lime and gypsum, so that the phosphorus recovery performance is increased, and the granulated material is disintegrated. The effect is that an excellent cured granulated product having almost no powder is obtained.
[0008]
Item 3. The phosphorus recovery material of the invention according to Item 3, wherein the composition of the quick-setting material is 40 to 60% by weight of alumina cement, 30 to 5% by weight of slaked lime, 30 to 35% by weight of gypsum in Item 1 or 2. %, The effect of further improving the phosphorus recovery performance and obtaining a more excellent cured granulated product with almost no collapse of the granulated product is obtained. Item 4. The phosphorus recovery material according to any one of Items 1 to 3, wherein the proportion of the quick-hardening material to the whole of the calcareous material and the siliceous material is 10 to 40% by weight. %, The room temperature curing time can be shortened, the phosphorus recovery performance is further increased, and an excellent effect that the granulated material is hardly disintegrated is exerted. Further, in the phosphorus recovery material according to the fifth aspect of the present invention, the calcium content (CaO) and the silica content (SiO 2 ) of the granulated product according to any one of the first to fourth aspects are CaO / SiO. When the molar ratio of 2 is 0.5 to 1.0, the phosphorus recovery performance is further increased, and an excellent effect that the granulated material is hardly disintegrated is exhibited.
[0009]
Item 6. The method for producing a phosphorus recovery material according to Item 6 is the method according to any one of Items 1 to 5, wherein the calcareous material, the siliceous material, and the quick-setting material are mixed and then granulated. Then, after curing at room temperature for 15 minutes to 1 hour, curing is performed in an autoclave. By mixing a fast-curing material, the curing time at room temperature can be reduced to 15 minutes to 1 hour, and the phosphorus recovery performance can be improved. This not only does not require a large-scale granulated material storage place, but also has an excellent effect that the granulated material is hardly disintegrated due to transfer during the manufacturing process of the phosphorus recovery material.
[0010]
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.
[0011]
The phosphorus recovery material of the present invention is a granulated product of a calcareous raw material, a siliceous raw material, and a fast-setting material, wherein the granulated material has been subjected to room-temperature curing and autoclave curing. The raw material usually contains components constituting the phosphorus recovery material, but cement, quicklime and the like are preferable. Similarly, the siliceous raw material preferably includes silica stone, diatomaceous earth, silicate clay, blast furnace slag, fly ash and the like. The quick-curing material is added to shorten the room-temperature curing time of the granulated product composed of the calcareous raw material and the siliceous material, and the room-temperature curing time is 15 minutes by adding the quick-setting material.に 1 hour. Therefore, the phosphorus recovery material of the present invention is a granulated product of a calcareous raw material, a siliceous raw material, and a fast-setting material, and the granulated material has been subjected to room-temperature curing and autoclave curing for 15 minutes to 1 hour. is there. The ordinary phosphorus recovery material is mainly composed of a calcareous raw material and a siliceous raw material. In the present invention, however, a rapid-hardening material is added to a phosphorus recovery material mainly composed of a calcareous raw material and a siliceous raw material. As the fast setting material, a mixture of alumina cement, slaked lime and gypsum is preferable, but not limited thereto. In the present invention, the mixture consisting of the calcareous raw material, the siliceous raw material and the quick-setting material is cured at room temperature after granulation, and the room-temperature curing time is preferably 15 minutes to 1 hour.
[0012]
The composition of the quick-setting material used in the present invention is particularly preferably in the range of 40 to 60% by weight of alumina cement, 30 to 5% by weight of slaked lime, and 30 to 35% by weight of gypsum. It has effects such as curing in a short time. Further, in the phosphorus recovery material of the present invention, the addition ratio of the quick-hardening material to the whole of the calcareous raw material and the siliceous raw material is 10 to 40% by weight. Preferably, this proportion is between 20 and 40% by weight. When the rate of addition of the fast-setting material is less than 10% by weight, the granulated material has a high disintegration rate in the short-time curing at room temperature, and therefore the yield of the granulated product cannot be said to be sufficient. On the other hand, when the addition ratio of the fast-setting material exceeds 40% by weight, not only tobermorite is not generated but also the disintegration rate of the granulated material is reduced, but the yield of the granulated material is extremely reduced.
[0013]
Particularly preferable effects are exhibited when the calcium content (CaO) and the silica content (SiO 2 ) of the granulated product used in the present invention are 0.5 to 1.0 in a molar ratio of CaO / SiO 2 .
[0014]
In the present invention, the method for producing a phosphorus recovery material according to any one of the above items 1 to 5, comprises mixing a calcareous raw material, a siliceous raw material, and a fast-setting material, granulating the mixture, and then mixing for 15 minutes to After curing at room temperature for 1 hour, the autoclave is cured. The granulated product obtained by granulation may have any shape, but is preferably formed in a substantially spherical shape or a hollow pipe shape. The shape of the hollow pipe is not limited to a circular ring having a circular cross section, and each cross section may be a polygonal shape such as an elliptical shape, a triangular shape, a quadrangular shape, a pentagonal shape, or an arbitrary shape. Although the size of the dephosphorizing material used in the present invention is not particularly limited, it is preferably a sphere having a diameter of about 1 to 15 mm in the case of a substantially spherical shape. In the case of extrusion molding, for example, a hollow pipe having an outer diameter of 3 to 20 mm, an inner diameter of 1 to 15 mm, and a length of about 0.1 to 2 m is preferable.
[0015]
The granulated product used in the present invention comprises a step of curing in the humid air (relative humidity of 80% or more) and a step of subsequently curing in an autoclave. Mixing the powder consisting of and softening the mixed material, forming the softened mixed material into a substantially spherical shape or extruding it into a hollow pipe shape, and curing the obtained molded product at a high temperature and a high pressure. To manufacture. For extruding the powder, a well-known extruder can be used. In the production method of the present invention, when a granulated product comprising a mixture of a calcareous raw material, a siliceous raw material, and a fast-setting material is cured by normal-temperature curing and high-temperature, high-pressure curing, calcium silicate hydrate is obtained. The calcium silicate hydrate is mainly tobermorite, but may be one or a combination of two or more of tobermorite, zonotlite, and hillebrandite.
[0016]
The granules used in the present invention are cured in 15 minutes to 1 hour by curing at room temperature. When the room temperature curing time is less than 15 minutes, the disintegration rate becomes 20% or more, which is outside the object of the present invention. If the room temperature curing time exceeds 1 hour, sufficient curing can be obtained, and no longer room temperature curing time is required. Further, in the production method of the present invention, after curing at room temperature, autoclave curing (high temperature and high pressure curing) is performed. The autoclave curing usually takes 2 to 10 hours at a pressure of 10 to 15 atm and a temperature of 180 to 200 ° C. Therefore, the conventional method for producing a phosphorus recovery material requires a long time of about 26 hours when the room temperature curing time and the autoclave curing time are combined, but the normal temperature curing time of 15 minutes is required in the method for producing a phosphorus recovery material of the present invention. １1 hour, and the autoclave curing time is 8 hours 15 minutes to 9 hours in total including about 8 hours, that is, 10 hours or less, so that the curing can be performed in a very short time as a whole, and the room temperature curing is short. Not only is it possible to obtain a granulated material having a disintegration rate that is almost the same as in a normal case even with time, and the phosphorus recovery performance is also improved.
[0017]
The present invention will be described below with reference to examples, but the present invention is not limited to these examples.
[0018]
[Reference Example] Production of quick-setting material 60 parts by weight of alumina cement, 30 parts by weight of anhydrous gypsum, and 10 parts by weight of slaked lime were mixed to produce a quick-setting material. Next, ordinary Portland cement, silica powder and the quick-setting material produced above were mixed and then granulated. Granulation was performed using a bread-type pelletizer. At that time, the molar ratio of CaO / SiO 2 becomes 0.75 based on the CaO content and SiO 2 content in all the raw materials including alumina cement, anhydrous gypsum and slaked lime, in the mixing ratio of the ordinary Portland cement and the silica stone powder. Was set as follows. Silica powder having a purity of 93% and a fineness of 3500 g / m 3 by the Blaine method was used. The granules obtained above were subjected to room temperature curing at a temperature of 20 ° C. for 18 hours, then immersed in water, drained, and then autoclaved at a pressure of 10 atm and 180 ° C. for 8 hours to obtain a phosphorus recovery material.
[0019]
[Example 1] After adding 5 parts by weight to 50 parts by weight of the quick-hardening material produced in Reference Example to the ordinary Portland cement and silica powder in the amounts shown in Table 1, mixing was performed, and a pan-type pelletizer was used. And granulated. The amounts of silica powder and ordinary Portland cement were set such that the molar ratio was 0.75. That is, the amounts of ordinary Portland cement, silica powder and the quick-setting material are as shown in Table 1. The obtained granules are subjected to room temperature curing at a temperature of 20 ° C. for 18 hours, then immersed in water, drained, and then autoclaved at a pressure of 10 atm and 180 ° C. for 8 hours to obtain a phosphorus recovery material (hereinafter referred to as a product). Obtained. At that time, the reaction product was identified by the unit volume mass, the pH value, and the X-ray diffraction of the product obtained by the yield of the granulated product and the autoclave curing. From these results, the properties of the product without the addition of the fast-setting material and the product with the addition were compared. Table 1 shows the test results. The term “water drainage” refers to a state in which the material is kept in the water and is slightly moistened on the surface when the material is taken out of the water after being immersed in the water.
[0020]
[Table 1]
2) Mass after filling a product (particle size: 1.0 to 1.7 mm) into a 1 L container 3) pH value when 1 g of sample is immersed in 100 mL of tap water for 1 hour 4) Product by powder X-ray diffraction method confirmation of the to: tobermorite (5CaO · 6SiO 2 · 5H 2 O)
CS: Type II anhydrous gypsum (CaSO 4 )
CSH: CSHGel (CaO.SiO 2 .H 2 O)
HG: Hydrogarnet (3CaO.Al 2 O 3 .6H 2 O)
5) The raw material hardens in the bread-type pelletizer, and the granulated material does not become spherical, but enlarges.
[0021]
As is evident from Table 1, the yield of the granulated product is improved by adding up to 40% of the fast-setting material. The unit volume mass of the product hardly changes even when the quick-hardening material is added. Also, the pH value of the product decreases with the addition of fast-setting materials. Further, X-ray diffraction shows that tobermorite is produced up to an addition ratio of the fast-setting material of up to 40% as in the case of the product without addition.
[0022]
[Example 2] After adding 5 to 50 parts by weight of a quick-setting material to ordinary Portland cement and silica powder, mixing was performed, and a granulated product having the composition shown in Table 1 of Example 1 was used using a pan-type pelletizer. And granulated. The room temperature curing time of the obtained granules was 15 minutes, 30 minutes, 1 hour and 18 hours, and the disintegration rate of the granules after each curing time when immersed in water was measured. For the disintegration rate, 200 g of the granulated product (particle size: 1.0 to 1.7 mm) is put into a 1.0 mm sieve, and the sieve is immersed in water. After about 1 minute, the sieve is slightly shaken, pulled out of the water, the sieve residue is transferred to a vat, and the weight after drying is measured. The difference between the initial weight and the weight after drying is taken and this is divided by the initial weight to calculate the disintegration rate. Table 2 shows the obtained results.
[0023]
[Table 2]
As is clear from Table 2, the product had a disintegration rate of 20% at room temperature curing time of 15 minutes by adding 10% of the quick-setting material. Further, by adding the fast-curing material in an amount of 20% to 40%, the disintegration rate at a room temperature curing time of 15 minutes was almost the same as that of a non-added product at room temperature curing time of 18 hours. Therefore, by adding the fast-setting material, the room temperature curing time could be significantly reduced.
[0025]
[Example 3] Rapid-hardening materials were produced in the mixing ratios shown in Table 3, and these quick-hardening materials were added to ordinary Portland cement and silica powder in an amount of 10 parts by weight, respectively, and then mixed, followed by mixing using a pan-type pelletizer. Granulated. At that time, the mixing ratio of ordinary Portland cement and silica powder was adjusted so that the molar ratio of CaO / SiO 2 became 0.75. At this time, the amount of the ordinary Portland cement was 48 parts by weight, and the amount of the silica powder was 42 parts by weight. The room temperature curing time of the obtained granules was 15 minutes, and the disintegration rate during immersion in water was measured. Table 3 shows the obtained results.
[0026]
[Table 3]
As is clear from Table 3, when the addition rate of slaked lime was increased while the addition rate of anhydrous gypsum in the fast-setting material was kept constant, the collapse rate was the lowest at an addition rate of 20%.
[0028]
Example 4 A rapidly hardening material was prepared by mixing 60 parts by weight of alumina cement, 30 parts by weight of anhydrous gypsum and 10 parts by weight of slaked lime. After adding 10 parts by weight of this quick-setting material to ordinary Portland cement and silica powder, they were mixed to obtain a raw material for production. At that time, the molar ratio of CaO / SiO 2 as shown in Table 4 were prepared phosphorus recovery material varied from 0.4 to 1.2. The room temperature curing time after granulation was 15 minutes, and the disintegration rate during immersion in water was measured. The product after autoclaving was measured for phosphorus recovery in a laboratory test using a small column. Table 4 shows the obtained results.
[0029]
[Method for measuring phosphorus recovery rate]
1. The test method raw water, potassium dihydrogen phosphate (Test, KH 2 PO 4), sodium hydroxide (reagent, NaOH) and using tap water PO 4 · P *: Using a simulated wastewater was adjusted to 50 mg / L did. The column was filled with a phosphorus recovery material having a bulk volume of 150 mL, and raw water was continuously passed through at a flow rate of 150 mL / h (SV = 1 hr -1 ), and the quality of treated water after 7 days was analyzed. The circulation speed of the reaction section was adjusted as needed so that the expansion rate of the phosphorus recovery material was about 20 to 25%. The analysis items were the amount of phosphorus (PO 4 .P) dissolved in the solution and the amount of suspended substances (in this case, aggregates containing phosphorus: SS).
[0030]
2. Definition of phosphorus recovery rate (1) PO 4 · P removal rate (%)
= (Raw water PO 4 · P concentration - treated water PO 4 · P concentration) / raw PO 4 · P concentration × 100
(2) Aggregation precipitation rate (5)
= [(Washing water total phosphorus concentration 1) - washing water PO 4 · P concentration) × amount of wash water] /
(Raw water PO 4 · P concentration × raw water through water) × 100
1) Total phosphorus concentration: P concentration + PO 4 · P concentration in SS (3) phosphorus recovery rate (%) = PO 4 · P removal rate - coagulating sedimentation rate [0031]
[Table 4]
As is clear from Table 4, Sample No. In the 12 comparative examples, the disintegration rate was high and the phosphorus recovery rate was low. Sample No. In Comparative Example No. 17, the disintegration rate was not bad, but in the small column experiment, coagulation and sedimentation occurred, and phosphorus was not crystallized on the phosphorus recovery material, indicating that the phosphorus recovery rate was low.
[0033]
The phosphorus recovery material according to the first aspect of the present invention is a granulated product of a calcareous raw material, a siliceous raw material, and a fast-setting material, and the granulated product is cured at room temperature and in an autoclave. As a result, since the granulated material to which the quick-setting material is added is subjected to room temperature curing and autoclave curing, not only does not adversely affect the phosphorus recovery material, but rather, the phosphorus recovery performance is increased, and the granulated material is increased. In addition to the excellent effect that there is almost no disintegration, the room temperature curing time can be shortened, and the excellent effect that a large-scale granule storage place is not required is exhibited. Further, in the phosphorus recovery material according to the second aspect of the present invention, in the first aspect, the quick-setting material is made of alumina cement, slaked lime and gypsum, so that the phosphorus recovery performance is increased and the collapse of the granulated material is reduced. This is effective in that an excellent hardened granulated product having almost no hardening can be obtained.
[0034]
In the phosphorus recovery material according to the third aspect of the present invention, in the first or second aspect, the composition of the quick-setting material is 40 to 60% by weight of alumina cement, 30 to 5% by weight of slaked lime, and 30 to 35% of gypsum. When the content is% by weight, the phosphorus recovery performance is further increased, and an effect of obtaining a more excellent cured granulated product, in which the granulated product is hardly disintegrated, is obtained. The phosphorus recovery material of the invention according to claim 4 of the present invention is the phosphor recovery material according to any one of claims 1 to 3, wherein the addition ratio of the quick-hardening material to the whole of the calcareous raw material and the siliceous raw material is 10 to 40. When the content is% by weight, the room-temperature curing time can be shortened, the phosphorus recovery performance is further increased, and an excellent effect that the granulated material is hardly disintegrated is exerted. Further, in the phosphorus recovery material according to the fifth aspect of the present invention, the calcium recovery component (CaO) and the silica content (SiO 2 ) of the granulated product according to any one of the first to fourth aspects are CaO / When the molar ratio of SiO 2 is 0.5 to 1.0, the phosphorus recovery performance is further increased, and an excellent effect that the granulated material is hardly disintegrated is exhibited.
[0035]
The method for producing a phosphorus recovery material according to claim 6 of the present invention is the method according to any one of claims 1 to 5, wherein the calcareous raw material, the siliceous raw material, and the quick-setting material are mixed and then granulated. Then, after curing at room temperature for 15 minutes to 1 hour, autoclaving is performed. By mixing a quick-curing material, the room temperature curing system can be reduced to 15 minutes to 1 hour, and phosphorus is recovered. The performance can be increased, not only does not require a large-scale granule storage space, but also has an excellent effect that there is almost no collapse of the granulated material due to transfer during the manufacturing process of the phosphorus recovery material. .
Claims (6)
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| JP2003045077A JP2004249263A (en) | 2003-02-21 | 2003-02-21 | Phosphorus recovering material and its production method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100366337C (en) * | 2005-09-29 | 2008-02-06 | 上海交通大学 | Method for preparing absorbent with phosphor concentration and phosphor reclaim function |
| JP2013202463A (en) * | 2012-03-27 | 2013-10-07 | Hokuriku Electric Power Co Inc:The | Phosphorus recovery material, phosphorus recovery method and producing method of fertilizer |
| WO2013168245A1 (en) * | 2012-05-09 | 2013-11-14 | 太平洋セメント株式会社 | Phosphorous-collecting material, method for producing phosphorous-collecting material, and phosphorous collection method |
| JP2013244466A (en) * | 2012-05-25 | 2013-12-09 | Taiheiyo Cement Corp | Phosphorus recovery material, method for producing phosphorus recovery material, and phosphorus recovery method |
-
2003
- 2003-02-21 JP JP2003045077A patent/JP2004249263A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100366337C (en) * | 2005-09-29 | 2008-02-06 | 上海交通大学 | Method for preparing absorbent with phosphor concentration and phosphor reclaim function |
| JP2013202463A (en) * | 2012-03-27 | 2013-10-07 | Hokuriku Electric Power Co Inc:The | Phosphorus recovery material, phosphorus recovery method and producing method of fertilizer |
| WO2013168245A1 (en) * | 2012-05-09 | 2013-11-14 | 太平洋セメント株式会社 | Phosphorous-collecting material, method for producing phosphorous-collecting material, and phosphorous collection method |
| JPWO2013168245A1 (en) * | 2012-05-09 | 2015-12-24 | 太平洋セメント株式会社 | Phosphorus recovery material, phosphorus recovery material manufacturing method, and phosphorus recovery method |
| JP2013244466A (en) * | 2012-05-25 | 2013-12-09 | Taiheiyo Cement Corp | Phosphorus recovery material, method for producing phosphorus recovery material, and phosphorus recovery method |
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