JP4126211B2 - Granulating agent for iron making and method for producing the same - Google Patents

Description

【００１４】
上記式中、Ｘは、ナトリウム、カリウム等のアルカリ金属；カルシウム、マグネシウム等のアルカリ土類金属；アンモニウム；モノエタノールアンモニウム、トリエタノールアンモニウム等の有機アンモニウムから選ばれる。
【００１５】
本発明は更に、アクリル酸（塩）系重合体を必須成分とする製鉄用造粒処理剤を製造する方法であって、上記製鉄用造粒処理剤の製造方法は、アルデヒド化合物を５〜１０００質量ｐｐｍ含有するアクリル酸（塩）を必須として重合することによりアクリル酸（塩）系重合体を製造する工程を含んでなる製鉄用造粒処理剤の製造方法でもある。
以下に、本発明を詳述する。
【００１６】
本発明の製鉄用造粒処理剤は、アクリル酸（塩）系重合体を必須成分とする。
本発明におけるアクリル酸（塩）系重合体とは、アクリル酸系重合体及び／又はその塩を意味し、このような重合体を１種用いてもよく、２種以上用いてもよい。
【００１７】
本発明の製鉄用造粒処理剤におけるアクリル酸（塩）系重合体の含有量としては、アクリル酸（塩）系重合体の種類や製鉄用造粒処理剤に所望される性能等により適宜設定すればよいが、製鉄用造粒処理剤中の水１００重量部に対して、０．１重量部以上であることが好ましく、また、３００重量部以下であることが好ましい。より好ましくは、５重量部以上であり、また、２５０重量部以下である。また、本発明の製鉄用造粒処理剤は、本発明の作用効果を損なわない範囲内で、又は、擬似粒化性等を向上するために、必要に応じて他の成分、例えば、生石灰等の従来公知の造粒添加剤等を含んでいてもよい。
【００１８】
上記製鉄用造粒処理剤としては、（１）アルデヒド化合物を５〜１０００質量ｐｐｍ含有するアクリル酸（塩）を必須として重合してなるアクリル酸（塩）系重合体を必須成分とする形態、（２）アクリル酸（塩）由来の構造単位を１０質量％以上有するアクリル酸（塩）系重合体を必須成分とし、アルデヒド化合物に由来する化合物を１００〜５００００質量ｐｐｍ含有する形態のいずれかとなる。なお、（１）の形態及び（２）の形態を組み合わせたものであってもよい。本明細書中、アクリル酸（塩）とは、（メタ）アクリル酸及び／又はその塩を意味する。
【００１９】
上記（１）の形態のアクリル酸（塩）系重合体において、アクリル酸（塩）に含まれるアルデヒド化合物が５質量ｐｐｍ未満であると、アクリル酸（塩）系重合体の分子量分布を充分に狭くすることができないため、分散剤としての作用、すなわち粉鉄鉱石を分散する作用が低下する傾向にあり、擬似粒化性が向上しないことになる。１０００質量ｐｐｍを超えると、アクリル酸（塩）の重合性が低下し、残量が増えることから、アクリル酸（塩）系重合体の純分が低下し、造粒性の向上効果が低下することになる。好ましくは、２０質量ｐｐｍ以上であり、また、８００質量ｐｐｍ以下である。より好ましくは、５０質量ｐｐｍ以上であり、また、５００質量ｐｐｍ以下である。
【００２０】
上記アルデヒド化合物としては、分子量が３０〜５００の低分子量のアルデヒドが好適であり、フルフラール、ベンズアルデヒド、ホルムアルデヒド、アセトアルデヒド、アクロレイン、クロトンアルデヒド等が挙げられる。これらは１種であってもよく、２種以上であってもよい。これらの中でも、フルフラールが好ましい。
【００２１】
上記（２）の形態のアクリル酸（塩）系重合体において、アクリル酸（塩）由来の構造単位が１０質量％未満であると、造粒処理において擬似粒化性が不充分となる。好ましくは、アクリル酸（塩）系重合体を構成する全構造単位１００質量％に対してアクリル酸（塩）由来の構造単位を３０質量％以上有するものであり、より好ましくは、５０質量％以上有するものである。
【００２２】
上記（２）の形態における製鉄用造粒処理剤は、アルデヒド化合物に由来する化合物を１００〜５００００質量ｐｐｍ含有するものであり、上記アルデヒド化合物としては、フルフラールが好適である。また、（１）の形態の製鉄用造粒処理剤においても、アルデヒド化合物に由来する化合物を１００〜５００００質量ｐｐｍ含有することが好ましい。このようなアルデヒド化合物に由来する化合物としては、アルデヒド化合物や該アルデヒド化合物が反応することにより生成するものが挙げられ、例えば、フルフラール由来の化合物として、安息香酸、安息香酸エステル、フルフリン酸、フルフリン酸エステル、下記式（２）に示す構造末端を有するアクリル酸（塩）系重合体等が挙げられる。これらは１種であってもよく、２種以上であってもよい。これらの中でも、下記式（２）に示す構造末端を有するアクリル酸（塩）系重合体が好ましい。
【００２３】
【化２】

【００２４】
上記アクリル酸（塩）系重合体を必須とする製鉄用造粒処理剤を製造する方法としては、アルデヒド化合物を５〜１０００質量ｐｐｍ含有するアクリル酸（塩）を必須として重合することによりアクリル酸（塩）系重合体を製造する工程を含んでなる製鉄用造粒処理剤の製造方法が好適であり、アクリル酸（塩）としては、精製処理を充分に行っていないためにアルデヒド化合物等の不純物を含有するもの、すなわち粗製アクリル酸（塩）を用いることが好ましい。
【００２５】
本発明におけるアクリル酸（塩）系重合体の重量平均分子量としては、１０００以上であることが好ましく、また、１００００００以下であることが好ましい。１０００未満であると、分散剤としての作用が低下するおそれがあり、１００００００を超えると、製鉄用造粒処理剤の粘度が高くなるおそれがある。より好ましくは、３０００以上であり、また、１０００００以下である。なお、本明細書中、重量平均分子量は、以下の測定条件で測定される値である。
【００２６】

【００２７】
上記アクリル酸（塩）系重合体としてはまた、分散度が３．０以下であることが好ましい。分散度が３．０を超えると、粉鉄鉱石を分散する作用が小さくなることに起因して、擬似粒子化させる作用が低下する傾向にある。より好ましくは、２．５以下である。なお、分散度とは、重量平均分子量／数平均分子量で算出される値であり、分子量分布を表すものである。数平均分子量は、重量平均分子量と同様の方法で測定される。
【００２８】
アクリル酸（塩）系重合体を必須成分とする製鉄用造粒処理剤を製造する方法であって、上記製鉄用造粒処理剤の製造方法は、アルデヒド化合物を５〜１０００質量ｐｐｍ含有するアクリル酸（塩）を必須として重合することによりアクリル酸（塩）系重合体を製造する工程を含んでなる製鉄用造粒処理剤の製造方法は、原料であるアクリル酸（塩）に含まれるアルデヒド化合物が重合中に反応して上述したアルデヒド化合物由来の化合物が生成するため、本発明の製鉄用造粒処理剤を製造することができることになる。このような製鉄用造粒処理剤の製造方法もまた、本発明の１つである。
【００２９】
上記製鉄用造粒処理剤の製造方法においては、アルデヒド化合物を５〜１０００質量ｐｐｍ含有するアクリル酸（塩）を必須とする単量体成分を用いて重合を行うことになる。本発明におけるアクリル酸（塩）としては、粗製アクリル酸（塩）を用いることが好ましいが、アクリル酸（塩）を製造後にアルデヒド化合物をアクリル酸（塩）に対して５〜１０００質量ｐｐｍとなるように添加したものを用いてもよい。また、単量体成分におけるアクリル酸（塩）の含有量としては、アクリル酸（塩）系重合体に所望する性能等により適宜設定することになるが、全単量体成分１００質量％に対して１０質量％以上とすることが好ましい。より好ましくは、３０質量％以上であり、更に好ましくは、５０質量％以上である。
【００３０】
上記アクリル酸塩としては、アクリル酸のナトリウム、カリウム等のアルカリ金属塩；カルシウム、マグネシウム等のアルカリ土類金属塩；アンモニウム塩；モノエタノールアミン、トリエタノールアミン等の有機アミシ塩が好適である。これらの塩は、１種であってもよく、２種以上であってもよい。これらの中でも、ナトリウム、カリウム等のアルカリ金属塩が好ましく、ナトリウム塩がより好ましい。
上記アルデヒド化合物やその好ましい形態としては、上述した製鉄用造粒処理剤におけるのと同様であり、フルフラールが好ましい。
【００３１】
上記アクリル酸（塩）としてはまた、メトキシハイドロキノン及び／又はフェノチアジンを含有することが好ましく、これらの含有量としては、メトキシハイドロキノンを４０〜１６０質量ｐｐｍ、フェノチアジンを０．１〜０．５質量ｐｐｍとすることが好ましい。メトキシハイドロキノンの含有量が、４０質量ｐｐｍ未満であると、アクリル酸（塩）の保存安定性が低く保管条件により突然重合が起こるおそれがあり、１６０質量ｐｐｍを超えると、重合性が低下し、残存単量体が多く残るおそれがある。フェノチアジンの含有量が、０．１質量ｐｐｍ未満であると、アクリル酸（塩）の保存安定性が低下するおそれがあり、０．５質量ｐｐｍを超えると、重合性が低下し、残存単量体が多く残るおそれがある。また、重合後の溶液の粘性を低下する目的で酢酸を５質量％を超えない範囲で添加してもよい。より好ましい含有量としては、メトキシハイドロキノンを５０〜１２０質量ｐｐｍ、フェノチアジンを０．２〜０．４質量ｐｐｍ、酢酸を０．５〜５％である。
【００３２】
上記単量体成分は、アクリル酸（塩）の他に、アクリル酸（塩）と共重合可能な他の共重合性単量体を含んでいてもよい。他の共重合性単量体としては、メタアクリル酸、マレイン酸、フマル酸、イタコン酸等のカルボキシル基を有する重合性単量体及びこれらの塩；ビニルスルホン酸、メタリルスルホン酸、アリルスルホン酸、３−（メタ）アリロキシ−２−ヒドロキシプロパンスルホン酸等のスルホン酸基を有する重合性単量体及びこれらの塩；（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸ヒドロキシエチル、（メタ）アクリル酸（Ｎ，Ｎ−ジメチルアミノエチル）、（メタ）アクリル酸（Ｎ，Ｎ−ジエチルアミノエチル）、（メタ）アクリル酸アミノエチル等の炭素数１〜１８の（メタ）アクリル酸アルキルエステル；（メタ）アクリルアミド、Ｎ−メチル（メタ）アクリルアミド、Ｎ−エチル（メタ）アクリルアミド、Ｎ，Ｎ−ジメチル（メタ）アクリルアミド等の（メタ）アクリルアミド及びその誘導体；酢酸ビニル；（メタ）アクリロニトリル；Ｎ−ビニル−２−ピロリドン、ビニルピリジン、ビニルイミダゾール等の塩基含有単量体；Ｎ−メチロール（メタ）アクリルアミド、Ｎ−ブトキシメチル（メタ）アクリルアミド等の架橋性を有する（メタ）アクリルアミド系単量体；ビニルトリメトキシシラン、ビニルトリエトキシシラン、γ−（メタ）アクリロイルプロピルトリメトキシシラン、ビニルトリス（２−メトキシエトキシ）シラン、アリルトリエトキシシラン等の加水分解性を有する基がケイ素原子に直結しているシラン系単量体；グリシジル（メタ）アクリレート、グリシジルエーテル（メタ）アクリレート等のエポキシ基を有する単量体；２−イソプロペニル−２−オキサゾリン、２−ビニル−２−オキサゾリン等のオキサゾリン基を有する単量体；２−アジリジニルエチル（メタ）アクリレート、（メタ）アクリロイルアジリジン等のアジリジン基を有する単量体；フッ化ビニル、フッ化ビニリデン、塩化ビニル、塩化ビニリデン等のハロゲン基を有する単量体；（メタ）アクリル酸と、エチレングリコール、ジエチレングリコール、プロピレングリコール、１，３−ブチレングリコール、ネオペンチルグリコール、１，６−ヘキサンジオール、トリメチロールプロパン、ペンタエリスリトール、ジペンタエリスリトール等の多価アルコールとのエステル化物等の分子内に不飽和基を複数有する多官能（メタ）アクリル酸エステル；メチレンビス（メタ）アクリルアミド等の分子内に不飽和基を複数有する多官能（メタ）アクリルアミド；ジアリルフタレート、ジアリルマレエート、ジアリルフマレート等の分子内に不飽和基を複数有する多官能アリル化合物；アリル（メタ）アクリレート；ジビニルベンゼン等が挙げられる。これらは単独で用いてもよく、２種以上を併用してもよい。これらの中でも、マレイン酸、フマル酸、イタコン酸等のカルボキシル基を有する重合性単量体が好適である。
【００３３】
上記共重合単量体のその他の例として、下記一般式（３）；
ＹＯ（Ｒ¹Ｏ）ｍＲ² （３）
（式中、Ｙは、炭素原子数２〜８のアルケニル基を表す。Ｒ²は、水素原子又は炭素原子数１〜３０の炭化水素基を表す。Ｒ¹Ｏは、炭素原子数２〜１８のオキシアルキレン基の１種又は２種以上の混合物を表す。ｍは、オキシアルキレン基の平均付加モル数であり１〜１０００の数を表す。）で表される不飽和（ポリ）アルキレングリコールエーテル系単量体が好適である。
【００３４】
上記一般式（３）において、オキシアルキレン基Ｒ¹Ｏの炭素原子数としては、２〜１８であるが、２〜８が好ましく、２〜４がより好ましい。また、炭素原子数２〜１８のオキシアルキレン基、すなわちエチレンオキシド、プロピレンオキシド、ブチレンオキシド、スチレンオキシド等の炭素原子数２〜１８のオキシドの中から選ばれる任意の２種類以上のアルキレンオキシド付加物におけるこれらのアルキレンオキシドの付加形態としては、ランダム付加、ブロック付加、交互付加等のいずれであってもよい。
【００３５】
上記不飽和（ポリ）アルキレングリコールエーテル系単量体としては、親水性と疎水性のバランス確保のため、オキシアルキレン基中にオキシエチレン基を必須成分として有するものが好ましい。より好ましくは、全オキシアルキレン基中５０モル％以上がオキシエチレン基であることであり、９０モル％以上がオキシエチレン基であることが更に好ましく、９５モル％以上がオキシエチレン基であることが特に好ましい。一般式（３）において、オキシアルキレン基の平均付加モル数ｍとしては、１〜１０００であるが、好ましくは２〜５００、より好ましくは５〜５００、更に好ましくは１０〜５００、特に好ましくは１５〜５００、最も好ましくは２０〜３００である。平均付加モル数が未満であると、得られる重合体の親水性が低下して分散性能が低下するおそれがあり、１０００を超えると、共重合反応性が低下するおそれがある。
【００３６】
上記一般式（３）において、Ｒ²は、水素原子又は炭素原子数１〜３０の炭化水素基であればよく、炭素原子数１〜３０の炭化水素基としては、炭素原子数１〜３０のアルキル基（脂肪族アルキル基又は脂環族アルキル基）、炭素原子数６〜３０のフェニル基、アルキルフェニル基、フェニルアルキル基、（アルキル）フェニル基で置換されたフェニル基、ナフチル基等のベンゼン環を有する芳香族基等が挙げられる。炭化水素基の炭素原子数が増大するに従って疎水性が大きくなり、分散性が低下するため、Ｒ²が炭化水素基の場合の炭素原子数としては、１〜２２が好ましく、１〜１８がより好ましく、１〜１２が更に好ましく、１〜４が特に好ましく、また、Ｒ²が水素原子の場合が最も好ましい。
【００３７】
上記一般式（３）において、Ｙで示されるアルケニル基の炭素原子数としては、２〜８であるが、３〜８が好ましく、３〜５がより好ましい。このようなアルケニル基としては、ビニル基、アリル基、メタリル基、３−ブテニル基、３−メチル−２−ブテニル基、２−メチル−３−ブテニル基、２−メチル−２−ブテニル基、１，１−ジメチル−２−プロペニル基等が挙げられる。これらの中でも、アリル基、メタリル基、３−メチル−３−ブテニル基が好ましい。
【００３８】
上記一般式（３）で表される不飽和（ポリ）アルキレングリコールエーテル系単量体は、アリルアルコール、メタリルアルコール、３−メチル−３−ブテン１−オール等の不飽和アルコールにアルキレンオキシドを１〜１０００モル付加して製造することができる。具体的には、（ポリ）エチレングリコールアリルエーテル、（ポリ）エチレングリコールメタリルエーテル、（ポリ）エチレングリコール３−メチル−３−ブテニルエーテル、（ポリ）エチレン（ポリ）プロピレングリコールアリルエーテル、（ポリ）エチレン（ポリ）プロピレングリコールメタリルエーテル、（ポリ）エチレン（ポリ）プロピレングリコール３−メチル−３−ブテニルエーテル、（ポリ）エチレン（ポリ）ブチレングリコールアリルエーテル、（ポリ）エチレン（ポリ）ブチレングリコールメタリルエーテル、（ポリ）エチレン（ポリ）ブチレングリコール３−メチル−３−ブテニルエーテル等が挙げられる。
【００３９】
上記他の共重合性単量体の含有量としては、全単量体成分中における上述のアクリル酸（塩）の割合を満足していればよいが、上述した単量体のうち疎水性重合性単量体については得られる重合体の水溶性を阻害する傾向があるので、その割合は水溶性を損なわない範囲とすることが好ましい。
【００４０】
上記製鉄用造粒処理剤の製造方法において、単量体成分を重合する際の重合方法や重合条件としては特に限定されず、所望する重合体の分子量等に応じて、従来公知の方法を適用すればよいが、重合開始剤として過酸化物を用いることが好ましい。これにより、得られる重合体の着色を抑えることができる。
【００４１】
上記過酸化物としては、過酸化水素；過硫酸ナトリウム、過硫酸カリウム、過硫酸アンモニウム等の過硫酸塩；過酸化ベンゾイル、過酸化ラウロイル、過酢酸、ジ−ｔ−ブチルパーオキサイド、クメンヒドロパーオキサイド等の有機過酸化物が好適である。これらは単独で用いてもよく、２種以上を併用してもよい。過酸化物の添加方法としては特に限定されるものではないが、その分解性を考慮すると、全使用量の半分以上、好ましくは全量を連続的に滴下することが好ましい。また、過酸化水素及びアスコルビン酸、ｔ−ブチルハイドロパーオキサイド及びロンガリット、過硫酸カリウム及び金属塩、過硫酸アンモニウム及び亜硫酸水素ナトリウム等の組み合わせからなるレドックス系重合開始剤もまた、好適に使用できる。
【００４２】
上記単量体成分を重合する際には、過酸化物以外の重合開始剤として、２，２′−アゾビス（２−アミジノプロパン）塩酸塩、４，４′−アゾビス−４−シアノバレリン酸、アゾビスイソブチロニトリル、２，２′−アゾビス（４−メトキシ−２，４−ジメチルバレロニトリル）等のアゾ系化合物；四塩化炭素、イソプロピルアルコール、トルエンを用いることもできる。これらは単独で用いてもよく、２種以上を併用してもよい。
【００４３】
上記単量体成分を重合する際には、必要に応じて、連鎖移動剤を用いてもよい。連鎖移動剤としては、亜硫酸塩、重亜硫酸塩、次亜リン酸塩、メルカプトプロピオン酸、チオグリコール酸が好適である。これらは単独で用いてもよく、２種以上を併用してもよい。
【００４４】
上記単量体成分を重合する際の重合濃度としては、全単量体成分の投入が終了した時点で重合体の濃度が７５質量％以下であることが好ましい。より好ましくは７０質量％以下である。７５質量％より大きくなると、重合粘度が高くなりすぎるおそれがある。
【００４５】
上記製鉄用造粒処理剤の製造方法により得られるアクリル酸（塩）系重合体を含む生成物は、そのまま製鉄用造粒処理剤として用いることができるものであるが、必要に応じて上述した他の成分１種又は２種以上を添加してもよい。このような製造方法により製造されるアクリル酸（塩）系重合体を含む製鉄用造粒処理剤は、製鉄用原料となる焼結鉱の製造において粉鉄鉱石等を造粒（擬似粒化）する作用に優れ、しかも低添加でも有効なものである。また、製鉄用原料となるペレットを製造する場合においても、粉鉄鉱石等をペレット化する作用に優れ、しかも低添加でも有効なものである。
【００４６】
本発明の製鉄用造粒処理剤により微粉の鉄鉱石を含む焼結原料やペレット原料等の製鉄用原料を造粒（擬似粒化又はペレット化）処理する際の使用量としては、焼結原料の鉱石（鉄鉱石）の造粒性（種類）や、アクリル酸（塩）系重合体の種類、使用する造粒機等に応じて適宜設定すればよいが、焼結原料（鉄鉱石、副原料、燃料等）１００重量部に対して製鉄用造粒処理剤中のアクリル酸（塩）系重合体が０．００１重量部以上となるようにすることが好ましく、また、２重量部以下となるようにすることが好ましい。０．００１重量部未満であると、本発明の作用効果を充分に発揮することができなくなるおそれがあり、２重量部を超えると、焼結原料に対する製鉄用造粒処理剤の添加量が多くなりすぎ、焼結原料の大きな固まりができ、該焼結原料の固まり内部が焼結されなくなる等の問題が生じるおそれがある。より好ましくは、焼結原料１００重量部に対するアクリル酸（塩）系重合体が０．００５重量部以上となるようにすることであり、また、１重量部以下となるようにすることである。
【００４７】
本発明の製鉄用造粒処理剤は、擬似粒子やペレットの崩れ防止剤として平均粒径０．１〜２００μｍの微粒子と併用することができる。崩れ防止剤は製鉄原料１００重量部に対し、０．１〜１０重量部添加することが好ましい。崩れ防止剤として、炭酸カルシウム、フライアッシュ、ベントナイト、カオリンクレー、ドロマイト、シリカフューム、無水石膏等が挙げられ、炭酸カルシウム、フライアッシュが特に好ましい。
【００４８】
【実施例】
以下に実施例を揚げて本発明を更に詳細に説明するが、本発明はこれらの実施例のみに限定されるものではない。なお、特に断りのない限り、「部」は、「重量部」を意味するものとする。
【００４９】
実施例１
温度計、還流冷却管及び攪拌機を備えた２．５リットルのＳＵＳ製セパラブルフラスコに、イオン交換水１９３．０ｇを仕込み、攪拌しながら沸点還流状態まで昇温した。次いで、還流状態を維持しながら、フルフラール３００質量ｐｐｍ、ベンズアルデヒド３００質量ｐｐｍ及びメトキシハイドロキノン８０質量ｐｐｍを含むアクリル酸ナトリウムの８０質量％水溶液４５０ｇを１８０分間かけて、３５質量％過酸化水素水溶液１１４．３ｇを９０分間かけて、１５質量％過硫酸ナトリウム水溶液１３３．３ｇを１９０分間かけて、４８質量％水酸化ナトリウム３３３．３ｇを１８０分間かけて、それぞれ別々の滴下ノズルから連続的に均一速度で滴下した。全ての滴下が終了した後、沸点還流状態を４０分間維持して、重合を完了した。その後、更に沸点還流状態を３０分間維持しながら、４８質量％水酸化ナトリウム水溶液６２．５ｇを攪拌下、徐々に滴下していき、最終中和度が９５％になるように中和を行った。このようにして得られたアクリル酸（塩）重合体の重量平均分子量及び分散度を以下のようにして測定した。結果を表２に示す。
また、得られた重合体水溶液を固形分換算で２１部となるように採取し、これをイオン交換水で希釈し、５２５０部にすることにより本発明にかかる製鉄用造粒処理剤（１）を得た。一方、表１に示す組成を有する焼結原料（製鉄用原料）を調製した。
【００５０】
【表１】

【００５１】
上記の焼結原料７００００部をドラムミキサーに投入し、回転速度２４ｍｉｎ^-1で１分間、予備攪拌した。その後、同回転速度で攪拌しながら、該焼結原料に、予め調製した本発明にかかる製鉄用造粒処理剤（１）５２５０部を霧吹きを用いて約１．５分間かけて噴霧した。焼結原料に対する高分子化合物の割合、すなわち、本発明の製鉄用造粒処理剤（１）に含有される高分子化合物の割合は０．０３％であった。噴霧後、更に同回転速度で３分間攪拌することにより、造粒操作を行った。
得られた擬似粒子を乾燥後、ふるいを用いて分級することにより、造粒後の粒径が０．２５ｍｍ以下の擬似粒子のＧＩ指数を求めた。この結果を、用いた高分子化合物の上記物性と合わせて表３に示す。
【００５２】
（分散度）
上記重量平均分子量と同様の方法で数平均分子量を測定し、下記式により算出した。
分散度＝重量平均分子量／数平均分子量
【００５３】
（ＧＩ指数測定方法）
造粒操作を行って得られた擬似粒子を８０℃で１時間乾燥後、ふるいを用いて分級することにより、その粒度（擬似粒度）及び平均粒径を求めた。造粒された擬似粒子のＧＩ指数とは、製鉄研究第２８８号（１９７６）９頁に開示されている評価方法の一つであり、核粒子の周りに付着する微粉粒子の割合を示す。なお、ＧＩ指数の測定は、製鉄研究第２８８号（１９７６）９頁に記載の方法に準じて行った。０．２５ｍｍ以下の擬似粒子のＧＩ指数（擬似粒化指数）は以下の式により計算した。
ＧＩ指数＝〔｛（造粒前の０．２５ｍｍ未満の原料の比率）−（造粒後の０．２５ｍｍ未満の原料の比率）｝／（造粒前の０．２５ｍｍ未満の原料の比率）〕×１００
【００５４】
実施例２及び参考例１
実施例１におけるアクリル酸ナトリウムに含まれるフルフラールの量を表２に示すように変更したこと以外は、実施例１と同様にしてアクリル酸（塩）重合体を得た。実施例１と同様に測定した重量平均分子量及び分散度を表２に示す。また、実施例１と同様にして擬似粒子のＧＩ指数を求めた。この結果を表３に示す。更に、重合体中の、上記式（２）に示す構造を末端に有するアクリル酸（塩）系重合体の含有量を、プロトンＮＭＲを用いて測定した。結果を表２に合わせて示す。
【００５５】
【表２】

【００５６】
比較例１
焼結原料７００００部に加え、生石灰８４０部を添加し、製鉄用造粒処理剤（１）５２５０部の代わりに蒸留水５６００部を用いた他は実施例１と同様にして擬似粒子のＧＩ指数を求めた。この結果を表３に示す。
【００５７】
【表３】

【００５８】
【発明の効果】
本発明の製鉄用造粒処理剤は、上述の構成からなり、粉鉄鉱石を分散する作用が向上して充分に擬似粒子化させることが可能であるため、製鉄用原料となる焼結鉱の製造において粉鉄鉱石等を造粒する作用に優れ、しかも低添加でも有効なものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a granulating agent for iron making and a method for producing the same. More specifically, the present invention relates to a granulating agent for iron making used for granulating fine iron ore and the like in the production of sintered ore as a raw material for iron making and a method for producing the same.
[0002]
[Prior art]
The iron making process is generally performed by charging an iron ore raw material mainly composed of iron ore into a blast furnace. Iron ore used as raw materials for iron making includes lump iron ore and fine iron ore. Of these, fine iron ore of 5 mm or less accounts for about 60% of iron ore produced in the world. If powdered iron ore is charged into an iron blast furnace as it is, it will affect the blast furnace operation, such as poor air permeability and unevenness, and an increase in the amount of gas ash generated. From these things, the sintered ore which agglomerated the fine iron ore is generally used as a blast furnace charging raw material in an iron manufacturing process. That is, at present, sintered ore is mainly used as a raw material for charging a blast furnace in an iron making process.
[0003]
In such a manufacturing process of sintered ore, sintering raw materials including iron ore, secondary raw materials, fuel, etc. are filled into a sintering machine at a specific height, and after forming a sintered bed, the surface layer is ignited. Thus, the sintering process is performed. As a sintering machine, a downward suction type is usually adopted. In the lower suction type sintering machine, air necessary for sintering is circulated by suction from the lower side of the sintering raw material, and fuel is burned from the upper side to the lower side of the sintering raw material, The sintering raw material is sintered. For this reason, if the sintering raw material contains a lot of fine powder, the air permeability decreases due to clogging and the like, and the combustion rate of coke, which is the fuel, becomes slow, so the production efficiency of the sintered ore decreases. It becomes.
[0004]
Therefore, in order to improve the air permeability in the sintering machine when sintering the sintered raw material, pretreatment such as granulating the sintered raw material to form pseudo particles is performed. For example, granulation operations such as mixing iron ore as a raw material for sintering, auxiliary materials, fuel, and the like, adding a small amount of water, and stirring with a granulator are performed. Pseudo particles are particles in which fine particles of 0.5 mm or less are generally attached to 1 to 3 mm core particles. The action required for such granulation is to improve the quasi-granulating property in which fine particles adhere to the periphery of the core particles, so that the quasi-particles are less likely to collapse in a wet zone, a dry zone, etc. in the sintering process. And so on. By making the sintering raw material into pseudo particles in this way, air permeability in the sintering raw material packed layer (sintering bed) on the sintering machine can be improved, and productivity in the sintering process can be improved. .
[0005]
In the pretreatment of such a sintering raw material, the granulation operation using only water has a poor effect of improving the pseudo-granulating property, and therefore the amount of fine powder contained in the sintering raw material cannot be reduced so much. For this reason, as a countermeasure for improving the pseudo-granulating property, a method of adding a granulating additive having an action as a binder to the sintered raw material has been proposed. As granulation additives, for example, bentonite, lignin sulfite (pulp waste liquor), starch, sugar, molasses, water glass, cement, gelatin, corn starch, etc. are being studied, but now, quick lime is widely used. Yes. Quick lime can promote the formation of pseudo-particles in the granulator, and also prevents the pseudo-particles from collapsing during the drying and heating process in the sintering process. It is said that the flow of
[0006]
However, binders such as quicklime and molasses are generally relatively expensive, and quicklime easily absorbs moisture and generates heat at this time, so that it is easy to handle. Furthermore, since quick lime currently used cannot obtain a sufficient effect unless the amount used is relatively large, the cost also increases in this respect. In the case of using quicklime, the current situation is that the amount used is reduced as much as possible. And even if 2 mass% or more of quicklime is added, the improvement effect of the pseudo-granulation property tends to reach a peak.
[0007]
Regarding pretreatment of a sintering raw material, JP-A-59-50129 relates to a pretreatment method for a sintering raw material using water containing a specific concentration of a dispersant and / or a specific concentration of a surfactant. Are disclosed, for example, an acrylic acid polymer, a maleic acid polymer, a styrene sulfonic acid polymer having an average molecular weight of 2,000 to 20,000. JP-A-61-61630 discloses a binder for producing sintered ore containing a water-soluble polymer compound such as a maleic acid polymer having an average molecular weight of 500 to 300,000.
[0008]
However, these techniques also have room for improvement to improve the pseudo-granulating property of the sintering raw material. That is, in order to make the sintering raw material pseudo-particle, the granulating additive is required to act as a binder of the sintering raw material. The required performance is that it can be granulated with a small amount of addition to reduce the cost of iron making and is inexpensive, and fine particles after drying so as not to collapse during transportation or in the moisture condensation zone of the sintered bed. Although it is difficult to return to the powder and the sintering strength is difficult to decrease, the yield of sintered ore is improved and the production efficiency is improved. However, it is required to further improve these performances. In addition, recently, with the depletion of high-quality ores, the deterioration of fine ore has also been severe, and the granulation property of the sintered raw material tends to be worse than before. There is a strong demand for a granulating agent for iron making that has a sufficiently high effect of reducing the amount and can improve the production efficiency of sintered ore.
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of the above situation, and is excellent in the action of granulating fine iron ore and the like in the production of sintered ore as a raw material for iron making, and is also effective even with low addition. It aims at providing an agent and its manufacturing method.
[0010]
[Means for Solving the Problems]
While examining various granulation treatment agents for iron making, the present inventors paid attention to the fact that acrylic acid (salt) -based polymers have an action as a granulation binder constituting the granulation treatment agent for iron making. . The granulating binder is usually granulated by adding water because water has the action of granulating powdered iron ore. However, with water alone, this will prevent powder from returning to powder when dried during sintering. This is to suppress a decrease in yield and production efficiency in the production of sintered ore. Normally, fine iron ore fine powder aggregates will not be able to fully exhibit the action of absorbing water and granulating, but when using acrylic acid (salt) -based polymer as a granulating binder, Demonstrates the action of breaking and dispersing the water-absorbing agglomerates, thereby increasing the amount of water that can exert the action of granulating fine iron ore, improving the pseudo-granulating property, By sufficiently dispersing the iron ore, water can exhibit an effect of efficiently granulating the fine iron ore. That is, normally, it was thought that the granulating binder should have a function as a binder, but in acrylic acid (salt) -based polymers, it has a function as a dispersing agent. It is thought that it will have an excellent action as a binder. In such an acrylic acid (salt) polymer, a polymer obtained by polymerizing acrylic acid (salt) containing a specific amount of an aldehyde compound as an essential component has a narrow molecular weight distribution of the polymer, resulting in fine iron ore. The ability to disperse stones can be improved and sufficiently pseudo-particles can be obtained, and it has been found that the performance required for a binder for granulation of sintering raw materials is sufficiently satisfied, and the above problems can be solved brilliantly. I came up with what I can do. Further, as the aldehyde compound, furfural is suitable, and a compound derived from an aldehyde compound using an acrylic acid (salt) -based polymer having a structural unit derived from acrylic acid (salt) of 10% by mass or more. It has been found that the action and effect of the present invention can be sufficiently exerted even when a specific amount is contained, and the present invention has been achieved. In addition, as the acrylic acid (salt), one that has been sufficiently removed of impurities by performing a purification treatment by distillation or the like in a production process including a step of vapor phase oxidation of propylene and / or acrolein is usually used. In the present invention, since the purification treatment is not sufficiently performed, it is possible to use a material containing impurities such as an aldehyde compound for the production of an acrylic acid (salt) polymer.
[0011]
That is, the present invention is a granulating agent for iron making containing an acrylic acid (salt) polymer as an essential component, and the acrylic acid (salt) polymer contains an aldehyde compound with respect to acrylic acid (salt). It is a granulating agent for iron making which is obtained by polymerizing acrylic acid (salt) containing 5 to 1000 mass ppm as an essential component.
[0012]
The present invention is also a granulating agent for iron making comprising an acrylic acid (salt) polymer as an essential component, wherein the acrylic acid (salt) polymer has 10 structural units derived from acrylic acid (salt). The above-mentioned granulation treatment agent for iron making is also a granulation treatment agent for iron making containing 100 to 50000 mass ppm of a compound derived from an aldehyde compound.
However, the structural unit derived from acrylic acid (salt) is a structural unit represented by the following general formula (1).
[0013]
[Chemical 1]

[0014]
In the above formula, X is selected from alkali metals such as sodium and potassium; alkaline earth metals such as calcium and magnesium; ammonium; organic ammonium such as monoethanolammonium and triethanolammonium.
[0015]
The present invention further relates to a method for producing a granulating agent for iron making comprising an acrylic acid (salt) polymer as an essential component, wherein the method for producing a granulating agent for iron making comprises 5 to 1000 aldehyde compounds. It is also a method for producing a granulating agent for iron making, which comprises a step of producing an acrylic acid (salt) -based polymer by polymerizing acrylic acid (salt) containing mass ppm as an essential component.
The present invention is described in detail below.
[0016]
The granulating agent for iron making according to the present invention comprises an acrylic acid (salt) polymer as an essential component.
The acrylic acid (salt) -based polymer in the present invention means an acrylic acid-based polymer and / or a salt thereof, and one kind or two or more kinds of such polymers may be used.
[0017]
The content of the acrylic acid (salt) -based polymer in the granulating agent for iron making of the present invention is appropriately set depending on the type of acrylic acid (salt) -based polymer, the performance desired for the granulating agent for iron making, and the like. However, it is preferably 0.1 parts by weight or more and preferably 300 parts by weight or less with respect to 100 parts by weight of water in the granulating agent for iron making. More preferably, it is 5 parts by weight or more and 250 parts by weight or less. In addition, the granulation treatment agent for iron making of the present invention is within the range not impairing the effects of the present invention, or other components such as quick lime, etc. The conventionally well-known granulation additive etc. may be included.
[0018]
As the above granulating agent for iron making, (1) an acrylic acid (salt) -based polymer obtained by polymerizing acrylic acid (salt) containing 5 to 1000 ppm by mass of an aldehyde compound as an essential component, (2) An acrylic acid (salt) -based polymer having a structural unit derived from acrylic acid (salt) of 10% by mass or more is an essential component, and a compound derived from an aldehyde compound is contained in an amount of 100 to 50000 mass ppm. . In addition, the form of (1) and the form of (2) may be combined. In this specification, acrylic acid (salt) means (meth) acrylic acid and / or a salt thereof.
[0019]
In the acrylic acid (salt) polymer in the form of (1) above, when the aldehyde compound contained in the acrylic acid (salt) is less than 5 ppm by mass, the molecular weight distribution of the acrylic acid (salt) polymer is sufficient. Since it cannot be narrowed, the action as a dispersant, that is, the action of dispersing fine iron ore tends to be reduced, and the pseudo-granulating property is not improved. If it exceeds 1000 ppm by mass, the polymerizability of acrylic acid (salt) will decrease and the remaining amount will increase, so the pure content of acrylic acid (salt) polymer will decrease and the effect of improving granulation will decrease. It will be. Preferably, it is 20 mass ppm or more, and is 800 mass ppm or less. More preferably, it is 50 mass ppm or more and 500 mass ppm or less.
[0020]
As the aldehyde compound, a low molecular weight aldehyde having a molecular weight of 30 to 500 is suitable, and examples thereof include furfural, benzaldehyde, formaldehyde, acetaldehyde, acrolein, and crotonaldehyde. These may be one type or two or more types. Among these, furfural is preferable.
[0021]
In the acrylic acid (salt) polymer in the form of (2) above, if the structural unit derived from acrylic acid (salt) is less than 10% by mass, the pseudo-granulating property is insufficient in the granulation treatment. Preferably, it has 30% by mass or more of structural units derived from acrylic acid (salt) with respect to 100% by mass of all structural units constituting the acrylic acid (salt) polymer, and more preferably 50% by mass or more. I have it.
[0022]
The granulating agent for iron making in the form of (2) above contains 100 to 50000 ppm by mass of a compound derived from an aldehyde compound, and furfural is suitable as the aldehyde compound. Moreover, also in the granulation processing agent for iron manufacture of the form of (1), it is preferable to contain 100-50000 mass ppm of the compound derived from an aldehyde compound. Examples of the compound derived from such an aldehyde compound include an aldehyde compound and a compound produced by the reaction of the aldehyde compound. For example, as a compound derived from furfural, benzoic acid, benzoic acid ester, furfuric acid, furfuric acid Examples thereof include an ester and an acrylic acid (salt) -based polymer having a structure terminal represented by the following formula (2). These may be one type or two or more types. Among these, an acrylic acid (salt) polymer having a structure terminal represented by the following formula (2) is preferable.
[0023]
[Chemical 2]

[0024]
As a method for producing a granulating agent for iron making which essentially comprises the above acrylic acid (salt) polymer, acrylic acid (salt) containing 5 to 1000 mass ppm of an aldehyde compound is essentially polymerized to produce acrylic acid. A method for producing a granulating agent for iron making comprising a step of producing a (salt) -based polymer is suitable, and acrylic acid (salt) is not sufficiently refined, so aldehyde compounds, etc. It is preferable to use those containing impurities, that is, crude acrylic acid (salt).
[0025]
The weight average molecular weight of the acrylic acid (salt) polymer in the present invention is preferably 1000 or more, and preferably 1000000 or less. If it is less than 1000, the action as a dispersant may be reduced, and if it exceeds 1000000, the viscosity of the granulating agent for iron making may be increased. More preferably, it is 3000 or more and 100000 or less. In the present specification, the weight average molecular weight is a value measured under the following measurement conditions.
[0026]

[0027]
The acrylic acid (salt) polymer preferably has a dispersity of 3.0 or less. When the degree of dispersion exceeds 3.0, the action of dispersing the fine iron ore tends to be small, and the action of making pseudo particles tends to decrease. More preferably, it is 2.5 or less. The dispersity is a value calculated by weight average molecular weight / number average molecular weight, and represents a molecular weight distribution. The number average molecular weight is measured by the same method as the weight average molecular weight.
[0028]
A method for producing a granulating agent for iron making comprising an acrylic acid (salt) -based polymer as an essential component, wherein the method for producing a granulating agent for iron making comprises an aldehyde compound in an amount of 5 to 1000 ppm by mass. A method for producing a granulating agent for iron making comprising a step of producing an acrylic acid (salt) polymer by polymerizing an acid (salt) as an essential component is an aldehyde contained in acrylic acid (salt) as a raw material. Since a compound reacts during superposition | polymerization and the compound derived from the aldehyde compound mentioned above produces | generates, the granulation processing agent for iron manufacture of this invention can be manufactured. A method for producing such a granulating agent for iron making is also one aspect of the present invention.
[0029]
In the manufacturing method of the said granulating agent for iron manufacture, it superposes | polymerizes using the monomer component which makes acrylic acid (salt) essential which contains 5-1000 mass ppm of aldehyde compounds as an essential component. Although it is preferable to use crude acrylic acid (salt) as acrylic acid (salt) in the present invention, the aldehyde compound becomes 5-1000 mass ppm with respect to acrylic acid (salt) after producing acrylic acid (salt). You may use what was added so. In addition, the content of acrylic acid (salt) in the monomer component is appropriately set depending on the performance desired for the acrylic acid (salt) polymer, but is 100% by mass based on the total monomer components. And preferably 10% by mass or more. More preferably, it is 30 mass% or more, More preferably, it is 50 mass% or more.
[0030]
Preferred examples of the acrylate include alkali metal salts such as sodium and potassium acrylates; alkaline earth metal salts such as calcium and magnesium; ammonium salts; and organic amic salts such as monoethanolamine and triethanolamine. These salts may be one kind or two or more kinds. Among these, alkali metal salts such as sodium and potassium are preferable, and sodium salts are more preferable.
As said aldehyde compound and its preferable form, it is the same as that in the granulating agent for iron manufacture mentioned above, and a furfural is preferable.
[0031]
The acrylic acid (salt) also preferably contains methoxyhydroquinone and / or phenothiazine, and these contents include 40 to 160 mass ppm of methoxyhydroquinone and 0.1 to 0.5 mass ppm of phenothiazine. It is preferable that When the content of methoxyhydroquinone is less than 40 ppm by mass, the storage stability of acrylic acid (salt) is low and there is a risk of sudden polymerization due to storage conditions. When the content exceeds 160 ppm by mass, the polymerizability decreases, A large amount of residual monomer may remain. If the content of phenothiazine is less than 0.1 ppm by mass, the storage stability of acrylic acid (salt) may be reduced, and if it exceeds 0.5 ppm by mass, the polymerizability will be reduced and the residual single amount May leave a lot of body. Moreover, you may add an acetic acid in the range which does not exceed 5 mass% in order to reduce the viscosity of the solution after superposition | polymerization. More preferable contents are 50 to 120 mass ppm for methoxyhydroquinone, 0.2 to 0.4 mass ppm for phenothiazine, and 0.5 to 5% for acetic acid.
[0032]
The monomer component may contain other copolymerizable monomer copolymerizable with acrylic acid (salt) in addition to acrylic acid (salt). Other copolymerizable monomers include polymerizable monomers having a carboxyl group such as methacrylic acid, maleic acid, fumaric acid, itaconic acid, and salts thereof; vinyl sulfonic acid, methallyl sulfonic acid, allyl sulfone. Acid, polymerizable monomers having a sulfonic acid group such as 3- (meth) allyloxy-2-hydroxypropanesulfonic acid, and salts thereof; methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic (Meth) acrylic acid (N, N-dimethylaminoethyl), (meth) acrylic acid (N, N-diethylaminoethyl), (meth) acrylic acid aminoethyl, etc. ) Acrylic acid alkyl ester; (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N (Meth) acrylamide and its derivatives such as N-dimethyl (meth) acrylamide; vinyl acetate; (meth) acrylonitrile; base-containing monomers such as N-vinyl-2-pyrrolidone, vinylpyridine, vinylimidazole; N-methylol ( (Meth) acrylamide monomers having crosslinkability such as (meth) acrylamide, N-butoxymethyl (meth) acrylamide; vinyltrimethoxysilane, vinyltriethoxysilane, γ- (meth) acryloylpropyltrimethoxysilane, vinyltris ( Silane monomers in which hydrolyzable groups such as 2-methoxyethoxy) silane and allyltriethoxysilane are directly bonded to silicon atoms; epoxy groups such as glycidyl (meth) acrylate and glycidyl ether (meth) acrylate Monomer having; 2- Monomers having an oxazoline group such as isopropenyl-2-oxazoline and 2-vinyl-2-oxazoline; Monomers having an aziridine group such as 2-aziridinylethyl (meth) acrylate and (meth) acryloylaziridine; Monomers having halogen groups such as vinyl fluoride, vinylidene fluoride, vinyl chloride, vinylidene chloride; (meth) acrylic acid, ethylene glycol, diethylene glycol, propylene glycol, 1,3-butylene glycol, neopentyl glycol, 1 Polyfunctional (meth) acrylic acid ester having a plurality of unsaturated groups in the molecule, such as esterified products with polyhydric alcohols such as 1,6-hexanediol, trimethylolpropane, pentaerythritol and dipentaerythritol; methylenebis (meth) acrylamide Intramolecular Polyfunctional (meth) acrylamide having a plurality of unsaturated groups; polyfunctional allyl compounds having a plurality of unsaturated groups in the molecule such as diallyl phthalate, diallyl maleate, diallyl fumarate; allyl (meth) acrylate; divinylbenzene It is done. These may be used alone or in combination of two or more. Among these, polymerizable monomers having a carboxyl group such as maleic acid, fumaric acid, and itaconic acid are preferable.
[0033]
As another example of the above-mentioned copolymerization monomer, the following general formula (3);
YO (R ¹ O) mR ² (3)
(In the formula, Y represents an alkenyl group having 2 to 8 carbon atoms. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. R ¹ O represents 2 to 18 carbon atoms. Represents one or a mixture of two or more oxyalkylene groups, wherein m is the average number of moles added of the oxyalkylene group and represents a number of 1 to 1000). System monomers are preferred.
[0034]
In the general formula (3), the number of carbon atoms of the oxyalkylene group R ¹ O is 2 to 18, preferably 2 to 8, and more preferably 2 to 4. In addition, in an oxyalkylene group having 2 to 18 carbon atoms, that is, in any two or more alkylene oxide adducts selected from oxides having 2 to 18 carbon atoms such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide and the like. The addition form of these alkylene oxides may be any of random addition, block addition, alternating addition, and the like.
[0035]
As the unsaturated (poly) alkylene glycol ether monomer, one having an oxyethylene group as an essential component in an oxyalkylene group is preferable in order to secure a balance between hydrophilicity and hydrophobicity. More preferably, 50 mol% or more of all oxyalkylene groups are oxyethylene groups, more preferably 90 mol% or more are oxyethylene groups, and 95 mol% or more are oxyethylene groups. Particularly preferred. In the general formula (3), the average added mole number m of the oxyalkylene group is 1 to 1000, preferably 2 to 500, more preferably 5 to 500, still more preferably 10 to 500, and particularly preferably 15. ~ 500, most preferably 20-300. When the average number of added moles is less, the hydrophilicity of the resulting polymer may be lowered and the dispersion performance may be lowered, and when it exceeds 1000, the copolymerization reactivity may be lowered.
[0036]
In the general formula (3), R ² may be a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and the hydrocarbon group having 1 to 30 carbon atoms may have 1 to 30 carbon atoms. Benzene such as alkyl groups (aliphatic alkyl groups or alicyclic alkyl groups), phenyl groups having 6 to 30 carbon atoms, alkylphenyl groups, phenylalkyl groups, phenyl groups substituted with (alkyl) phenyl groups, naphthyl groups, etc. Examples thereof include an aromatic group having a ring. As the number of carbon atoms in the hydrocarbon group increases, the hydrophobicity increases and the dispersibility decreases. Therefore, the number of carbon atoms when R ² is a hydrocarbon group is preferably 1 to 22, more preferably 1 to 18 1 to 12 is more preferable, 1 to 4 is particularly preferable, and R ² is most preferably a hydrogen atom.
[0037]
In the said General formula (3), as a carbon atom number of the alkenyl group shown by Y, it is 2-8, 3-8 are preferable and 3-5 are more preferable. Such alkenyl groups include vinyl, allyl, methallyl, 3-butenyl, 3-methyl-2-butenyl, 2-methyl-3-butenyl, 2-methyl-2-butenyl, 1 , 1-dimethyl-2-propenyl group and the like. Among these, an allyl group, a methallyl group, and a 3-methyl-3-butenyl group are preferable.
[0038]
The unsaturated (poly) alkylene glycol ether monomer represented by the general formula (3) is an alkylene oxide in an unsaturated alcohol such as allyl alcohol, methallyl alcohol, and 3-methyl-3-buten1-ol. It can be produced by adding 1 to 1000 mol. Specifically, (poly) ethylene glycol allyl ether, (poly) ethylene glycol methallyl ether, (poly) ethylene glycol 3-methyl-3-butenyl ether, (poly) ethylene (poly) propylene glycol allyl ether, (poly ) Ethylene (poly) propylene glycol methallyl ether, (poly) ethylene (poly) propylene glycol 3-methyl-3-butenyl ether, (poly) ethylene (poly) butylene glycol allyl ether, (poly) ethylene (poly) butylene glycol Examples include methallyl ether and (poly) ethylene (poly) butylene glycol 3-methyl-3-butenyl ether.
[0039]
The content of the other copolymerizable monomer may satisfy the above-mentioned ratio of acrylic acid (salt) in all monomer components. Since the water-soluble monomer tends to inhibit the water solubility of the resulting polymer, the proportion is preferably set in a range that does not impair the water solubility.
[0040]
In the method for producing a granulating agent for iron making, the polymerization method and polymerization conditions for polymerizing the monomer component are not particularly limited, and conventionally known methods are applied depending on the molecular weight of the desired polymer. However, it is preferable to use a peroxide as the polymerization initiator. Thereby, coloring of the polymer obtained can be suppressed.
[0041]
Examples of the peroxide include hydrogen peroxide; persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; benzoyl peroxide, lauroyl peroxide, peracetic acid, di-t-butyl peroxide, cumene hydroperoxide Organic peroxides such as are preferred. These may be used alone or in combination of two or more. The method for adding the peroxide is not particularly limited, but considering its decomposability, it is preferable to continuously drop more than half, preferably the entire amount, of the total amount used. A redox polymerization initiator composed of a combination of hydrogen peroxide and ascorbic acid, t-butyl hydroperoxide and Rongalite, potassium persulfate and metal salts, ammonium persulfate, sodium hydrogensulfite and the like can also be suitably used.
[0042]
When the monomer component is polymerized, 2,2′-azobis (2-amidinopropane) hydrochloride, 4,4′-azobis-4-cyanovaleric acid, azo is used as a polymerization initiator other than peroxide. Azo compounds such as bisisobutyronitrile and 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile); carbon tetrachloride, isopropyl alcohol, and toluene can also be used. These may be used alone or in combination of two or more.
[0043]
When polymerizing the monomer component, a chain transfer agent may be used as necessary. As the chain transfer agent, sulfite, bisulfite, hypophosphite, mercaptopropionic acid, and thioglycolic acid are suitable. These may be used alone or in combination of two or more.
[0044]
As the polymerization concentration when polymerizing the monomer components, the polymer concentration is preferably 75% by mass or less when all the monomer components have been charged. More preferably, it is 70 mass% or less. If it exceeds 75% by mass, the polymerization viscosity may be too high.
[0045]
The product containing the acrylic acid (salt) -based polymer obtained by the above-described method for producing a granulating agent for iron making can be used as it is as a granulating agent for iron making. One or more other components may be added. A granulating agent for iron making containing an acrylic acid (salt) -based polymer produced by such a production method is used to granulate (pseudo-granulate) fine iron ore and the like in the production of sintered ore as a raw material for iron making. In addition, it is effective even with low addition. Further, when producing pellets as raw materials for iron making, it is excellent in the action of pelletizing fine iron ore and the like, and is effective even with low addition.
[0046]
The amount used when granulating (pseudo-granulating or pelletizing) a raw material for iron making such as a sintering raw material or pellet raw material containing fine iron ore with the granulating agent for iron making of the present invention is as follows. May be set as appropriate according to the granulation property (type) of the ore (iron ore), the type of acrylic acid (salt) polymer, the granulator used, etc. Preferably, the acrylic acid (salt) -based polymer in the granulating agent for iron making is 0.001 part by weight or more with respect to 100 parts by weight of the raw material, fuel, etc., and 2 parts by weight or less. It is preferable to do so. If the amount is less than 0.001 part by weight, the effects of the present invention may not be sufficiently exhibited. If the amount exceeds 2 parts by weight, the amount of iron granulation treatment agent added to the sintered raw material is large. Therefore, there is a risk that a large mass of the sintered raw material may be formed, and problems such as the inside of the mass of the sintered raw material becoming unsintered may occur. More preferably, the acrylic acid (salt) -based polymer with respect to 100 parts by weight of the sintering raw material is 0.005 parts by weight or more, and 1 part by weight or less.
[0047]
The granulating agent for iron making of the present invention can be used in combination with fine particles having an average particle size of 0.1 to 200 μm as an anti-fracturing agent for pseudo particles and pellets. The collapse preventing agent is preferably added in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the iron-making raw material. Examples of the collapse preventing agent include calcium carbonate, fly ash, bentonite, kaolin clay, dolomite, silica fume and anhydrous gypsum, and calcium carbonate and fly ash are particularly preferable.
[0048]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited only to these examples. Unless otherwise specified, “parts” means “parts by weight”.
[0049]
Example 1
In a 2.5-liter SUS separable flask equipped with a thermometer, a reflux condenser, and a stirrer, 193.0 g of ion-exchanged water was charged, and the temperature was raised to the boiling point reflux state while stirring. Next, while maintaining the reflux state, 450 g of an 80 mass% aqueous solution of sodium acrylate containing 300 mass ppm of furfural, 300 mass ppm of benzaldehyde, and 80 mass ppm of methoxyhydroquinone was added over a period of 180 minutes. 3g over 90 minutes, 153.3% aqueous 15% sodium persulfate solution over 190 minutes, and 333.3g 48% sodium hydroxide over 180 minutes, each from a continuous dropping nozzle at a uniform rate. It was dripped. After all the addition was completed, the boiling point reflux state was maintained for 40 minutes to complete the polymerization. Thereafter, while maintaining the boiling point reflux state for 30 minutes, 62.5 g of a 48 mass% sodium hydroxide aqueous solution was gradually added dropwise with stirring, and neutralization was performed so that the final neutralization degree was 95%. . The weight average molecular weight and the degree of dispersion of the acrylic acid (salt) polymer thus obtained were measured as follows. The results are shown in Table 2.
Moreover, the obtained polymer aqueous solution is extract | collected so that it may become 21 parts in conversion of solid content, This is diluted with ion-exchange water, By making it 5250 parts, the granulation processing agent for iron manufacture concerning this invention (1) Got. On the other hand, a sintering raw material (raw material for iron making) having the composition shown in Table 1 was prepared.
[0050]
[Table 1]

[0051]
70000 parts of the above sintered raw material was put into a drum mixer and pre-stirred for 1 minute at a rotation speed of 24 min ⁻¹ . Then, 5250 parts of the granulating agent for iron making (1) prepared in advance according to the present invention was sprayed on the sintered raw material over about 1.5 minutes using a spray bottle while stirring at the same rotational speed. The ratio of the polymer compound to the sintering raw material, that is, the ratio of the polymer compound contained in the granulating agent for iron making (1) of the present invention was 0.03%. After spraying, the granulation operation was performed by further stirring for 3 minutes at the same rotational speed.
The obtained pseudo particles were dried and classified using a sieve to obtain the GI index of the pseudo particles having a granulated particle size of 0.25 mm or less. The results are shown in Table 3 together with the physical properties of the polymer compound used.
[0052]
(Dispersity)
The number average molecular weight was measured by the same method as the above weight average molecular weight, and calculated by the following formula.
Dispersity = weight average molecular weight / number average molecular weight
(GI index measurement method)
The pseudo particles obtained by the granulation operation were dried at 80 ° C. for 1 hour and then classified using a sieve to obtain the particle size (pseudo particle size) and the average particle size. The GI index of the granulated pseudo particles is one of the evaluation methods disclosed in Steel Manufacturing Research No. 288 (1976), page 9, and indicates the ratio of fine particles adhering around the core particles. The GI index was measured according to the method described in Steel Manufacturing Research No. 288 (1976), page 9. The GI index (pseudo graining index) of pseudo particles of 0.25 mm or less was calculated by the following formula.
GI index = [{(ratio of raw material less than 0.25 mm before granulation) − (ratio of raw material less than 0.25 mm after granulation)} / (ratio of raw material less than 0.25 mm before granulation) ] × 100
[0054]
Example 2 and Reference Example 1
An acrylic acid (salt) polymer was obtained in the same manner as in Example 1 except that the amount of furfural contained in sodium acrylate in Example 1 was changed as shown in Table 2. Table 2 shows the weight average molecular weight and the degree of dispersion measured in the same manner as in Example 1. Further, the GI index of the pseudo particles was determined in the same manner as in Example 1. The results are shown in Table 3. Further, the content of an acrylic acid (salt) polymer having a terminal structure of the above formula (2) in the polymer was measured using proton NMR. The results are shown in Table 2.
[0055]
[Table 2]

[0056]
Comparative Example 1
In addition to 70000 parts of the sintered raw material, 840 parts of quicklime was added, and the GI index of the pseudo particles was the same as in Example 1 except that 5600 parts of distilled water was used instead of 5250 parts of the granulating agent for iron making (1). Asked. The results are shown in Table 3.
[0057]
[Table 3]

[0058]
【The invention's effect】
The granulating agent for iron making according to the present invention has the above-described configuration, and the effect of dispersing the fine iron ore can be improved and sufficiently made into pseudo particles. It is excellent in the action of granulating fine iron ore in production, and is effective even with low addition.

Claims (5)

A granulating agent for iron making comprising an acrylic acid (salt) polymer as an essential component,
The acrylic acid (salt) polymer is a crude acrylic acid (salt) containing 5-1000 mass ppm of an aldehyde compound and / or an acrylic acid (salt) and then the aldehyde compound is converted to acrylic acid (salt). A granulation treatment agent for iron making, characterized in that it is polymerized with an essential addition of 5 to 1000 ppm by mass . A granulating agent for iron making comprising an acrylic acid (salt) polymer as an essential component,
The acrylic acid (salt) -based polymer has a structural unit derived from acrylic acid (salt) of 10% by mass or more,
The iron-making granulation treatment agent contains 100 to 50000 ppm by mass of a compound derived from an aldehyde compound. The granulation treatment agent for iron making according to claim 1 or 2, wherein the aldehyde compound is furfural. A method for producing a granulating agent for iron making comprising an acrylic acid (salt) polymer as an essential component,
The manufacturing method of the granulation treatment agent for iron making comprises producing crude acrylic acid (salt) and / or acrylic acid (salt) containing 5-1000 mass ppm of aldehyde compound, and then converting the aldehyde compound to acrylic acid (salt). Production of a granulating agent for iron making, characterized by comprising a step of producing an acrylic acid (salt) -based polymer by polymerizing as an essential component added to 5 to 1000 ppm by mass Method. The said aldehyde compound is a furfural, The manufacturing method of the granulation processing agent for iron manufacture of Claim 4 characterized by the above-mentioned.