JP3799989B2

JP3799989B2 - Method for producing deinked pulp from waste paper with high ash content

Info

Publication number: JP3799989B2
Application number: JP2000330453A
Authority: JP
Inventors: 信一内山; 洋二磯部; 和夫島倉; 季凌; 悌幸松田
Original assignee: Oji Holdings Corp; Oji Paper Co Ltd
Current assignee: New Oji Paper Co Ltd; Oji Holdings Corp
Priority date: 2000-10-30
Filing date: 2000-10-30
Publication date: 2006-07-19
Anticipated expiration: 2020-10-30
Also published as: JP2002138380A

Description

【０００１】
【発明の属する技術分野】
本発明は、高灰分印刷古紙から脱墨パルプを製造する方法に関し、さらに詳しくは高灰分印刷古紙を脱墨再生する工程における脱墨パルプ製造能力、灰分除去性能を向上せしめて、低灰分印刷古紙からの脱墨パルプと同等乃至それ以下に灰分含有量が低減されている高灰分印刷古紙からの脱墨パルプの製造を可能とした脱墨パルプの製造方法に関する。
【０００２】
【従来の技術】
従来の脱墨パルプの製造設備においては、古紙原料の灰分含有量に関係なく、離解・除塵・漂白・脱墨の各工程にしたがった脱墨パルプの製造が行われている。また、従来の脱墨パルプの製造設備では、製品パルプの灰分を下げる必要がある場合には、灰分除去装置を洗浄設備として最終工程に組み入れるのが主流であった。
しかしながら、古紙原料の灰分が高くなると歩留が悪化し、原料古紙量が増えるため、設備処理能力以上の処理が求められることとなり、その結果、設備の脱墨性能が著しく低下して製品の残灰分が大きくなってしまう問題があった。
たとえば、コート印刷古紙の脱墨方法については特開平２−２２１４８０号公報に記載されているが、コート紙の脱墨方法に伴う排水の処理問題や製品中の残存灰分については全く記載がない。
【０００３】
また、印刷用紙・情報用紙に配合する古紙再生パルプは高白色度が求められるので、従来から色上古紙等の高白色度の古紙を原料に使用することがあった。しかし、古紙灰分が高く、既存設備での対応が難しく設備を新設する必要があるので、現状では効果的に使用できているとは言えない。このような理由から、1998年の紙・板紙への古紙利用は５５％であるのに対して、印刷・情報用紙への古紙利用は１８％にとどまっているのが現状である〔（財）古紙再生促進センターによる推定値〕。
このことは、都市近郊では印刷工場も多く存在し、都市型の工場では郊外型の工場に比べて印刷損紙が集まりやすいが、高灰分印刷古紙を低灰分印刷古紙と同様に処理する方法が確立されていなかったため、有効利用が進まなかったことが理由であると考えられる。
【０００４】
更に、都市型の工場の場合、排水量・ＣＯＤ負荷などの規制が極めて厳しい現状があるのに対して、高灰分印刷古紙を処理すると排水中の固形分濃度が上昇するためにＣＯＤカット率の低下を招き、ＣＯＤ負荷が上昇する。排水中の固形分を低下させるためには希釈水量を増やせば良いが、それに伴って排水量も増加するので得策ではない。従って、都市型の工場では、高灰分印刷古紙を処理するためには排水処理装置を増強することを求められこととなる。
【０００５】
【発明が解決しようとする課題】
本発明は、高灰分印刷古紙の脱墨方法における上記のような問題を解消させ、従来方法より洗浄水量が少なくても従来方法と同等以上の白色度の脱墨パルプを得ることができる方法を提供することを目的とするものである。
【０００６】
【課題を解決するための手段】
上記の目的を達成することができる本発明は、基本的には離解した印刷古紙を脱墨工程に送るに先立って、灰分除去工程で原料の灰分濃度を低減せしめる処理を行うことを特徴とする方法であり、以下の各発明を包含する。
【０００７】
（１）灰分を全固形分中１５〜３５ｗｔ％含有する高灰分印刷古紙を離解する離解工程、離解した古紙懸濁液を原料濃度２〜４ｗｔ％に希釈する希釈工程、希釈した原料懸濁液を紙料入口ゾーン、置換洗浄ゾーン及び仕上がりゾーンを有するドラムタイプの灰分除去装置に導入して灰分を優先的に除去すると共に、原料濃度を５〜９ｗｔ％に濾過濃縮して灰分を全固形分中７〜２５ｗｔ％まで減少させる灰分除去工程、及び灰分除去工程から得られる原料を除塵・過酸化水素漂白・脱墨の順序で処理する脱墨パルプ製造工程を有することを特徴とする高灰分印刷古紙から脱墨パルプを製造する方法。
【０００８】
(2) 前記灰分除去工程において発生する灰分含有濾液を処理して固形分濃度０．１ｗｔ％以下である低固形分濃度の濾液を得る濾液処理工程をさらに有しており、該低固形分濃度の濾液を前記離解工程、希釈工程、灰分除去工程及び脱墨パルプ製造工程の少なくとも１工程に希釈水及び／又は洗浄水として循環し使用することを特徴とする(1) 記載の高灰分印刷古紙から脱墨パルプを製造する方法。
【０００９】
(3) 前記濾液処理工程は、前記灰分除去工程において発生する灰分含有濾液中の固形分を浮上分離する工程であることを特徴とする(2) 記載の高灰分印刷古紙から脱墨パルプを製造する方法。
【００１０】
【発明の実施の形態】
本発明の脱墨方法が処理対象とする高灰分印刷古紙は、灰分を１５％以上含有する印刷古紙であり、一般的には灰分を１５〜３５％含有する印刷古紙である。灰分１５％未満であれば、通常のチラシ込み新聞と同等の灰分量であり、通常設備で処理できる。しかし、本発明の方法によれば、これらの古紙も高灰分印刷古紙と一緒に処理することが可能である。
高灰分印刷古紙の例としては、塗工紙（アート紙、コート紙、軽量コート紙）に印刷がされている灰分を１５〜３５％含む印刷古紙及び非塗工紙であるが灰分を１５％〜３５％含む模造古紙等が挙げられる。
【００１１】
本発明の脱墨方法における前記離解工程は、固形分濃度１２〜１８％になるように原料古紙と希釈水を入れ、更に薬品（水酸化ナトリウム）を対パルプ０〜１．０重量％、好ましくは０．０１〜０．５重量％を加え、離解時間１０〜３０分、好ましくは１０〜２５分、更に好ましくは１０〜１８分、離解温度１０〜５０℃、好ましくは３０〜５０℃で離解する原料古紙離解工程である。
【００１２】
本発明の脱墨方法における前記希釈工程は、前記離解工程で離解した古紙原料を次の灰分除去工程へ移送するため希釈する工程である。希釈工程における希釈水としては、後記濾液処理工程から得られる灰分量が全固形分中７〜２５ｗｔ％まで減少されている処理水を使用することが好ましい。
【００１３】
本発明の脱墨方法における前記灰分除去工程は、原料中の灰分を優先的に除去し、繊維分のロスを最小限に止めるための洗浄工程である。一般的には、エキストラクター、フォールウォッシャー（商品名：栄工機製）、ダブルニップシックナー（商品名：石川島産業機械製）等の既存の装置を使用して行うことができる。本発明の方法においては、上記フォールウォッシャーを使用して実験を行っている。
【００１４】
上記フォールウォッシャーは、紙料入口ゾーン、置換洗浄ゾーン、仕上がりゾーンの３ゾーンを有するドラムタイプの洗浄機である。従来のドラムタイプの洗浄機は、紙料がマット状に形成されてしまいワイヤーとの接触回数が減少することにより洗浄効果が発揮されにくくなるデメリットがあったが、フォールウォッシャーはマットを形成させないように強力な高速攪拌羽根を取りつけてある。また、紙料処理には入口濃度を２〜４％の濃度で使用できるため、処理後の排水量を減少させることができる。また繊維分のロスも少ないという特徴がある。（「紙パ技協誌」53巻第９号第64〜67頁、特に65頁図１、特開平８−176985号公報、特開平９−188986号公報参照）
【００１５】
本発明の方法における脱墨パルプ製造工程は、除塵・漂白・脱墨の各工程からなる。除塵はスクリーン・クリーナーで原料中の異物を取り除く工程である。本発明の方法の実施にはスリットスクリーン（１段目0.25ｍｍスリット、２段目0.20ｍｍスリット）を使用した。クリーナーは重量異物を取り除くものである。
【００１６】
漂白は薬品を使用してパルプを白くする工程である。古紙再生には一般的には過酸化水素、ハイドロサルファイド、二酸化チオ尿素、ハイポ等が使用される。本発明の実施例では過酸化水素を使用している。
過酸化水素漂白工程は、過酸化水素対パルプ０．７〜３．５重量％、水酸化ナトリウム対パルプ１．５〜３．０重量％、珪酸ナトリウム対パルプ０／５〜１．０重量％（水酸化ナトリウム換算）で、漂白時間は１〜４時間、漂白パルプ濃度は２０〜３５％、漂白温度は５０〜７５℃で行われる。
【００１７】
脱墨工程は、フローテーターで空気にインキを吸着させてインキを系外に除去する工程である。フローテーターでの処理濃度は０．７〜１．５％、フローテーターでの処理温度は１０〜５０℃、好ましくは３０〜４５℃であり、脱墨剤は対パルプ０〜０．３重量％添加して行われる。
【００１８】
濾液処理工程は、灰分除去工程で発生する濾液の固形分を除去するための処理工程である。処理水は離解工程、希釈工程、灰分除去工程及び上記除塵・漂白・脱墨の各工程の希釈水及び／又は洗浄水として再利用することが好ましい。
濾液処理は浮上分離法によって行うことが好ましく、本発明の実施例ではポセイドンサターン（商品名：相川鉄工製）を使用している。ポセイドンサターンはセル本体を竪型円筒形とし、セル内に吹き込まれる微細気泡の単位当りの密度を高め、気泡と懸濁固形分（ＳＳ）との接触・付着機会を大きくすることにより固形分分離性能を高めようとしたものである。（「紙パ技協誌」第53巻第６号第52〜61頁、特に59頁図13、特表平９−503434号公報、特表平11−502761号公報参照。）
【００１９】
灰分除去工程で発生する濾液は、固形分濃度が１重量％であり、一般的に洗浄水として使用することができず、排水となることが多かった。本発明の方法では、灰分除去工程で発生する濾液を濾液処理工程で固形分の浮上分離処理をすることで処理水の固形分濃度を０．１重量％以下とすることができることから、この処理水を離解工程及び希釈工程の希釈水、灰分除去工程の洗浄水、除塵工程、漂白工程及び脱墨工程における希釈水及び／又は洗浄水等として再利用することが可能となり、それによって洗浄水の固形分濃度が低下するので節水が可能となった。
【００２０】
【実施例】
以下、本発明を実施例に基いてより詳細に説明する。なお、特に断らない限り、原料濃度は灰分込みの固形分濃度を意味し、薬品添加率は重量％である。
【００２１】
〔測定方法〕
各工程の原料灰分をＴＡＰＰＩ２１１に準じて測定した。
製品パルプの白色度は分光白色度測色計（スガ試験機製）で測定した。
【００２２】
実施例１
コート紙を主体とする高灰分上質印刷古紙（灰分含有量２６．２％）１００％の原料をパルパーに仕込み原料濃度１５％、水酸化ナトリウム添加率対パルプ０．３％、離解時間１５分、離解温度３５℃で離解した（離解工程）。離解後、離解原料を３．６％に希釈し（希釈工程）、次いで、灰分除去装置（フォールウォッシャー：栄工機製）に導入し、原料濃度７．４％まで濃縮した（灰分除去工程）。灰分除去装置の濾液（固形分濃度１．０％）は濾液処理装置（ポセイドンサターン：相川鉄工製）で処理し、固形分濃度０．１％の処理水を得た。
得られた処理水は、古紙の離解工程における希釈水、離解後の離解原料の希釈工程における希釈水、灰分除去工程における灰分除去装置の洗浄水及び後記脱墨パルプ製造工程における洗浄水として使用した。
【００２３】
灰分除去工程から得られる灰分除去後のパルプスラリ−は３％に希釈後、脱墨パルプ製造設備（王子製紙春日井工場の既存古紙再生パルプ製造設備）にて処理し製品パルプを製造した。漂白条件は、過酸化水素添加率対パルプ２．５％、水酸化ナトリウム対パルプ添加率２．３％、珪酸ナトリウム添加率対パルプ水酸化ナトリウム換算０．７％、パルプ濃度２８％、漂白時間２時間３０分、漂白温度６５℃で行った。脱墨条件は、フローテーター処理濃度１．２％、フローテーター処理温度４２℃、脱墨剤添加率０．２５％で行った。脱墨剤は脂肪酸系脱墨剤「ＤＩ−１０５０」（商品名：花王製）を使用した。
【００２４】
比較例１
コート紙を主体とする高灰分上質印刷古紙（灰分含有量２６．２％）１００％の原料をパルパーに仕込み原料濃度１５％、水酸化ナトリウム添加率対パルプ０．３％、離解時間１５分、離解温度３５℃で離解した（離解工程）。離解後の離解原料を３．６％に希釈し（希釈工程）、パルプスラリ−は３％に希釈後、実施例１と同一の既存の脱墨パルプ製造設備（王子製紙春日井工場の既存古紙再生パルプ製造設備）にて処理し製品パルプを製造した。漂白条件、脱墨条件は実施例１と同条件で行った。
以上の結果を表１に示す。
【００２５】
【表１】

【００２６】
表１中、洗浄水原単位とは、製品パルプ１ＡＤＴ（エアードライトン：水分１０％含む）を製造するのに使用する洗浄水の総量である。
【００２７】
実施例２
灰分を１５％以上含む模造古紙を主体とする高灰分上質印刷古紙（灰分含有量１５．９％）１００％の原料をパルパーに仕込み原料濃度１５％、水酸化ナトリウム添加率対パルプ０．３％、離解時間１５分、離解温度３５℃で離解した（離解工程）。離解後の離解原料を３．０％に希釈し（希釈工程）、次いで、灰分除去装置（フォールウォッシャー：栄工機製）に導入し、原料濃度６．８％まで濃縮した（濃縮工程）。灰分除去装置の濾液は白水処理装置（ポセイドンサターン：相川鉄工製）で処理し、固形分濃度０．１％の処理水を得た。
得られた処理水は、古紙の離解工程における離解の希釈水、離解後の離解原料の希釈工程における希釈水、灰分除去工程における灰分除去装置の洗浄水及び後記脱墨パルプ製造工程の洗浄水として使用した。
【００２８】
灰分除去工程から得られる灰分除去後のパルプスラリ−は３％に希釈後、脱墨パルプ製造設備（王子製紙春日井工場の既存古紙再生パルプ製造設備）にて処理し、製品パルプを製造した。漂白条件は過酸化水素添加率対パルプ１．５％、水酸化ナトリウム対パルプ添加率１．８％、珪酸ナトリウム添加率対パルプ水酸化ナトリウム換算０．６％、パルプ濃度２８％、漂白時間２時間３０分、漂白温度６０℃で行った。脱墨条件はフローテーター処理濃度１．２％、フローテーター処理温度４０℃、脱墨剤添加率０．２５％で行った。脱墨剤は脂肪酸系脱墨剤「ＤＩ−１０５０」（商品名：花王製）を使用した。
【００２９】
比較例２
灰分を１５％以上含む模造古紙を主体とする高灰分上質印刷古紙（灰分含有量１５．９％）１００％の原料をパルパーに仕込み原料濃度１５％、水酸化ナトリウム添加率対パルプ０．３％、離解時間１５分、離解温度３５℃で離解した（離解工程）。離解後の離解原料を３．６％に希釈し（希釈工程）、パルプスラリ−は３％に希釈後、実施例２と同一の既存の脱墨パルプ製造設備（王子製紙春日井工場の既存古紙再生パルプ製造設備）にて処理して製品パルプを製造した。漂白条件、脱墨条件は実施例２と同条件で行った。
以上の結果を表２に示す。
【００３０】
【表２】

【００３１】
実施例３
灰分を３０％以上含む塗工紙を主体とする高灰分上質印刷古紙（灰分含有量３１．９％）１００％の原料をパルパーに仕込み原料濃度１５％、水酸化ナトリウム添加率対パルプ０．３％、離解時間１５分、離解温度３５℃で離解した（離解工程）。離解後の離解原料を３．８％に希釈し（希釈工程）、次いで、灰分除去装置（フォールウォッシャー：栄工機製）に導入し、原料濃度７．８％まで濃縮した（灰分除去工程）。灰分除去装置の濾液は白水処理装置（ポセイドンサターン：相川鉄工製）で処理し、固形分濃度０．１％の処理水を得た。
得られた処理水は、古紙の離解工程における希釈水、離解後の離解原料の希釈工程における希釈水、灰分除去工程における灰分除去装置の洗浄水及び後記脱墨パルプ製造工程の洗浄水として使用した。
【００３２】
灰分除去後のパルプスラリ−は３％に希釈後、脱墨パルプ製造設備（王子製紙春日井工場の既存古紙再生パルプ製造設備）にて処理して製品パルプを製造した。漂白条件は、過酸化水素添加率対パルプ３．０％、水酸化ナトリウム対パルプ添加率２．４％、珪酸ナトリウム添加率対パルプ水酸化ナトリウム換算０．８％、パルプ濃度３０％、漂白時間２時間３０分、漂白温度６８℃で行った。脱墨条件はフローテーター処理濃度１．４％、フローテーター処理温度４４℃、脱墨剤添加率０．２５％で行った。脱墨剤は脂肪酸系脱墨剤脂肪酸系脱墨剤「ＤＩ−１０５０」（商品名：花王製）を使用した。
【００３３】
比較例３
灰分を３０％以上含む塗工紙を主体とする高灰分上質印刷古紙（灰分含有量３１．９％）１００％の原料をパルパーに仕込み原料濃度１５％、水酸化ナトリウム添加率対パルプ０．３％、離解時間１５分、離解温度３５℃で離解した（離解工程）。離解後の離解原料を３．８％に希釈し（希釈工程）、パルプスラリ−は３％に希釈後、実施例２と同一の既存の脱墨パルプ製造設備（王子製紙春日井工場の既存古紙再生パルプ製造設備）にて処理して製品パルプを製造した。漂白条件、脱墨条件は実施例３と同条件で行った。
以上の結果を表３に示す。
【００３４】
【表３】

【００３５】
【発明の効果】
上記表１，２及び３に示したように、本発明によれば、離解後に灰分除去を行うことで製品パルプの灰分は１．２〜２．２％低下し、製品パルプ白色度は３．５〜３．８％上昇した。洗浄水原単位は２２〜６０ｍ³／ＡＤＴ削減でき、比率としては１８〜４４％削減することができた。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing deinked pulp from high ash printed waste paper, and more specifically, improved low deinked pulp production capacity and ash removal performance in a process of deinking and recycling high ash printed waste paper, thereby reducing low ash printed waste paper. It is related with the manufacturing method of the deinking pulp which enabled manufacture of the deinking pulp from the waste paper of high ash content in which the ash content was reduced to the same or less than the deinking pulp from
[0002]
[Prior art]
In conventional deinked pulp manufacturing equipment, deinked pulp is manufactured in accordance with the steps of disaggregation, dust removal, bleaching, and deinking regardless of the ash content of the waste paper raw material. In addition, in conventional deinked pulp manufacturing equipment, when it is necessary to lower the ash content of product pulp, it has been the mainstream to incorporate an ash removal device into the final process as a cleaning equipment.
However, if the ash content of the waste paper raw material becomes high, the yield deteriorates and the amount of raw paper waste increases, which requires processing that exceeds the equipment processing capacity. There was a problem that the ash became large.
For example, the method of deinking coated printed paper is described in Japanese Patent Application Laid-Open No. Hei 2-221480, but there is no description of the wastewater treatment problem associated with the deinking method of coated paper and the residual ash content in the product.
[0003]
Further, since recycled paper pulp used in printing paper and information paper is required to have high whiteness, conventionally, high whiteness wastepaper such as colored wastepaper has been used as a raw material. However, since the amount of waste paper ash is high and it is difficult to cope with existing equipment, it is necessary to newly install equipment, so it cannot be said that it can be used effectively at present. For these reasons, the use of used paper for paper and paperboard in 1998 was 55%, while the use of used paper for printing and information paper was only 18%. Estimated value by Recycled Paper Recycling Promotion Center].
This is because there are many printing factories in the suburbs of cities, and it is easier to collect printing waste paper in urban factories than in suburban factories, but there is a method of treating high ash printed waste paper in the same way as low ash printed waste paper. The reason is that effective use did not progress because it was not established.
[0004]
Furthermore, in the case of urban factories, the regulations on wastewater volume and COD load are extremely strict, but when high-ash printed waste paper is processed, the solid content concentration in the wastewater increases, resulting in a decrease in the COD cut rate. And the COD load increases. In order to reduce the solid content in the wastewater, the amount of diluted water may be increased, but the amount of wastewater increases accordingly, which is not a good idea. Therefore, in an industrial factory, it is required to reinforce a wastewater treatment device in order to process high ash printed waste paper.
[0005]
[Problems to be solved by the invention]
The present invention eliminates the above-mentioned problems in the deinking method for high-ash printed waste paper, and provides a method capable of obtaining deinked pulp having a whiteness equal to or higher than that of the conventional method even if the amount of washing water is smaller than that of the conventional method. It is intended to provide.
[0006]
[Means for Solving the Problems]
The present invention capable of achieving the above-mentioned object is basically characterized in that, prior to sending the disaggregated printed paper to the deinking process, a process for reducing the ash concentration of the raw material in the ash removal process is performed. The method includes the following inventions.
[0007]
(1) A disaggregation step for disaggregating high-ash printed waste paper containing 15 to 35 wt% of ash in the total solid content, a dilution step for diluting the disaggregated waste paper suspension to a raw material concentration of 2 to 4 wt%, and a diluted raw material suspension Is introduced into a drum-type ash content removal device having a paper material inlet zone, a replacement washing zone and a finish zone to remove ash content preferentially, and filter and concentrate the raw material concentration to 5 to 9 wt% to reduce the ash content to the total solid content. High ash printing characterized by having an ash removal process for reducing the content to 7 to 25 wt%, and a deinked pulp manufacturing process for processing the raw material obtained from the ash removal process in the order of dust removal, hydrogen peroxide bleaching, and deinking A method for producing deinked pulp from waste paper.
[0008]
(2) The method further comprises a filtrate treatment step of treating the ash-containing filtrate generated in the ash removal step to obtain a filtrate having a low solid content concentration of 0.1 wt% or less, and the low solid content concentration The recycled high-ash content paper according to (1), wherein the filtrate is used as dilution water and / or washing water in at least one of the disaggregation step, dilution step, ash removal step and deinking pulp manufacturing step. To produce deinked pulp from
[0009]
(3) The filtrate treatment step is a step of levitating and separating the solid content in the ash-containing filtrate generated in the ash removal step, wherein the deinked pulp is produced from the high ash printed waste paper according to (2) how to.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The high ash printed waste paper to be treated by the deinking method of the present invention is a printed waste paper containing 15% or more of ash, and generally a printed waste paper containing 15 to 35% of ash. If the ash content is less than 15%, the amount of ash content is the same as that of ordinary newspapers with leaflets, and can be processed with normal equipment. However, according to the method of the present invention, these waste papers can be treated together with the high ash printed waste paper.
Examples of high ash printed waste paper include printed waste paper containing 15-35% ash printed on coated paper (art paper, coated paper, lightweight coated paper) and non-coated paper, but 15% ash Examples include imitation waste paper containing ~ 35%.
[0011]
In the de-inking step in the deinking method of the present invention, raw waste paper and dilution water are added so that the solid content concentration is 12 to 18%, and further, chemical (sodium hydroxide) is added to 0 to 1.0% by weight of pulp, preferably Is added at 0.01 to 0.5% by weight, and the disaggregation time is 10 to 30 minutes, preferably 10 to 25 minutes, more preferably 10 to 18 minutes, and the disaggregation temperature is 10 to 50 ° C, preferably 30 to 50 ° C. This is a waste paper disaggregation process.
[0012]
The dilution step in the deinking method of the present invention is a step of diluting the used paper raw material that has been disaggregated in the disaggregation step to transfer it to the next ash removal step. As dilution water in the dilution step, it is preferable to use treated water in which the amount of ash obtained from the filtrate treatment step described later is reduced to 7 to 25 wt% in the total solid content.
[0013]
The ash removal step in the deinking method of the present invention is a washing step for preferentially removing ash in the raw material and minimizing fiber loss. Generally, it can be performed using an existing apparatus such as an extractor, a fall washer (trade name: manufactured by Eiko Co., Ltd.), a double nip thickener (trade name: manufactured by Ishikawajima Industrial Machinery Co., Ltd.). In the method of the present invention, an experiment is performed using the fall washer.
[0014]
The fall washer is a drum type washing machine having three zones of a paper inlet zone, a replacement washing zone, and a finishing zone. The conventional drum type washer has the demerit that it becomes difficult for the cleaning effect to be exerted by reducing the number of contact with the wire because the stock is formed in a mat shape, but the fall washer does not form a mat A powerful high-speed stirring blade is attached. Moreover, since the entrance concentration can be used at a concentration of 2 to 4% for the paper processing, the amount of waste water after the processing can be reduced. There is also a feature that there is little loss of fiber. (Refer to "Paper Technology Association Vol. 53, No. 9, pages 64-67, especially page 65, Fig. 1, JP-A-8-176985, JP-A-9-188986")
[0015]
The deinked pulp manufacturing process in the method of the present invention comprises dust removal, bleaching, and deinking processes. Dust removal is a process of removing foreign substances in the raw material with a screen cleaner. A slit screen (first stage 0.25 mm slit, second stage 0.20 mm slit) was used in carrying out the method of the present invention. The cleaner removes heavy foreign matter.
[0016]
Bleaching is the process of using chemicals to whiten the pulp. Generally, hydrogen peroxide, hydrosulfide, thiourea dioxide, hypo, etc. are used for recycling used paper. In the embodiment of the present invention, hydrogen peroxide is used.
The hydrogen peroxide bleaching step consists of hydrogen peroxide to pulp 0.7 to 3.5 wt%, sodium hydroxide to pulp 1.5 to 3.0 wt%, sodium silicate to pulp 0/5 to 1.0 wt% In terms of sodium hydroxide, the bleaching time is 1 to 4 hours, the bleaching pulp concentration is 20 to 35%, and the bleaching temperature is 50 to 75 ° C.
[0017]
The deinking step is a step of removing the ink out of the system by adsorbing the ink to the air with a floatator. The treatment concentration in the flotator is 0.7 to 1.5%, the treatment temperature in the flotator is 10 to 50 ° C, preferably 30 to 45 ° C, and the deinking agent is 0 to 0.3% by weight with respect to the pulp. It is done by adding.
[0018]
The filtrate treatment step is a treatment step for removing the solid content of the filtrate generated in the ash removal step. The treated water is preferably reused as dilution water and / or washing water in the disaggregation step, dilution step, ash content removal step, and the dust removal / bleaching / deinking step.
The filtrate treatment is preferably carried out by a flotation separation method, and Poseidon Saturn (trade name: manufactured by Aikawa Tekko) is used in the examples of the present invention. Poseidon Saturn has a cell-shaped cylindrical body, increases the density per unit of fine bubbles blown into the cell, and increases the chance of contact and adhesion between bubbles and suspended solids (SS) to separate solids. It is intended to improve performance. (See "Paper Paper Technical Journal" Vol. 53, No. 6, pp. 52-61, especially Fig. 59, Fig. 13, JP 9-503434 and JP 11-502761.)
[0019]
The filtrate generated in the ash removal step has a solid content concentration of 1% by weight, and generally cannot be used as washing water, and often becomes drainage. In the method of the present invention, the solid content concentration of the treated water can be reduced to 0.1% by weight or less by subjecting the filtrate generated in the ash removal step to the floating separation treatment of the solid content in the filtrate treatment step. Water can be reused as dilution water in the disaggregation step and dilution step, washing water in the ash removal step, dust removal step, bleaching step and deinking step, and / or washing water, etc. As the solid content is reduced, water saving is possible.
[0020]
【Example】
Hereinafter, the present invention will be described in more detail based on examples. Unless otherwise specified, the raw material concentration means the solid content concentration including ash, and the chemical addition rate is wt%.
[0021]
〔Measuring method〕
The raw material ash content in each step was measured according to TAPPI 211.
The whiteness of the product pulp was measured with a spectral whiteness colorimeter (manufactured by Suga Test Instruments).
[0022]
Example 1
High-ash high-quality printed waste paper mainly composed of coated paper (ash content 26.2%) 100% raw material is charged into a pulper, raw material concentration 15%, sodium hydroxide addition rate vs. pulp 0.3%, disaggregation time 15 minutes, Disaggregation was performed at a disaggregation temperature of 35 ° C. (disaggregation step). After the disaggregation, the disaggregated raw material was diluted to 3.6% (dilution step), then introduced into an ash removal device (Fall Washer: manufactured by Eiko), and concentrated to a raw material concentration of 7.4% (ash removal step). The filtrate (solid content concentration 1.0%) of the ash removal device was treated with a filtrate treatment device (Poseidon Saturn: manufactured by Aikawa Tekko Co., Ltd.) to obtain treated water with a solid content concentration of 0.1%.
The obtained treated water was used as dilution water in the disintegration process of waste paper, dilution water in the dilution process of the disaggregation raw material after disaggregation, washing water in the ash removal apparatus in the ash removal process, and washing water in the deinking pulp manufacturing process described later. .
[0023]
The pulp slurry after ash removal obtained from the ash removal step was diluted to 3%, and then processed at a deinking pulp manufacturing facility (existing waste paper recycled pulp manufacturing facility at Oji Paper Kasugai Mill) to produce a product pulp. The bleaching conditions were: hydrogen peroxide addition rate to pulp 2.5%, sodium hydroxide to pulp addition rate 2.3%, sodium silicate addition rate to pulp sodium hydroxide equivalent 0.7%, pulp concentration 28%, bleaching time 2 hours 30 minutes at a bleaching temperature of 65 ° C. The deinking conditions were a flow rate of 1.2%, a flow rate of 42 ° C., and a deinking agent addition rate of 0.25%. The deinking agent used was a fatty acid-based deinking agent “DI-1050” (trade name: manufactured by Kao).
[0024]
Comparative Example 1
High-ash high-quality printed waste paper mainly composed of coated paper (ash content 26.2%) 100% raw material is charged into a pulper, raw material concentration 15%, sodium hydroxide addition rate vs. pulp 0.3%, disaggregation time 15 minutes, Disaggregation was performed at a disaggregation temperature of 35 ° C. (disaggregation step). The disaggregated raw material after disaggregation is diluted to 3.6% (dilution process), the pulp slurry is diluted to 3%, and the same existing deinked pulp manufacturing equipment as in Example 1 (existing recycled paper from Oji Paper's Kasugai Mill) The product pulp was produced by processing at the production facility. Bleaching conditions and deinking conditions were the same as in Example 1.
The results are shown in Table 1.
[0025]
[Table 1]

[0026]
In Table 1, the washing water intensity is the total amount of washing water used to produce product pulp 1ADT (air dryton: containing 10% moisture).
[0027]
Example 2
High ash high quality printing waste paper (mainly ash content 15.9%) consisting mainly of imitation waste paper containing 15% or more of ash content into a pulper, raw material concentration 15%, sodium hydroxide addition rate vs. pulp 0.3% The disaggregation time was 15 minutes and the disaggregation temperature was 35 ° C. (disaggregation process). The disaggregated raw material after disaggregation was diluted to 3.0% (dilution step), then introduced into an ash removal device (fall washer: manufactured by Eiko), and concentrated to a raw material concentration of 6.8% (concentration step). The filtrate of the ash removal device was treated with a white water treatment device (Poseidon Saturn: manufactured by Aikawa Tekko Co., Ltd.) to obtain treated water with a solid content concentration of 0.1%.
The treated water thus obtained is used as dilution water in the disintegration process of waste paper, dilution water in the dilution process of the disaggregation raw material after disaggregation, washing water in the ash removal apparatus in the ash removal process, and washing water in the deinking pulp manufacturing process described later. used.
[0028]
The pulp slurry after ash removal obtained from the ash removal step was diluted to 3%, and then processed at a deinking pulp manufacturing facility (existing recycled paper pulp manufacturing facility at Oji Paper Kasugai Mill) to produce a product pulp. Bleaching conditions were hydrogen peroxide addition rate to pulp 1.5%, sodium hydroxide to pulp addition rate 1.8%, sodium silicate addition rate to pulp sodium hydroxide equivalent 0.6%, pulp concentration 28%, bleaching time 2 The time was 30 minutes and the bleaching temperature was 60 ° C. The deinking conditions were a flow rate of 1.2%, a flow rate of 40 ° C., and a deinking agent addition rate of 0.25%. The deinking agent used was a fatty acid-based deinking agent “DI-1050” (trade name: manufactured by Kao).
[0029]
Comparative Example 2
High ash high quality printing waste paper (mainly ash content 15.9%) consisting mainly of imitation waste paper containing 15% or more of ash content into a pulper, raw material concentration 15%, sodium hydroxide addition rate vs. pulp 0.3% The disaggregation time was 15 minutes and the disaggregation temperature was 35 ° C. (disaggregation process). The disaggregated raw material after the disaggregation is diluted to 3.6% (dilution process), the pulp slurry is diluted to 3%, and the same existing deinked pulp manufacturing equipment as in Example 2 (the existing recycled paper pulp of Oji Paper Kasugai Mill) The product pulp was produced by processing at the production facility. Bleaching conditions and deinking conditions were the same as in Example 2.
The results are shown in Table 2.
[0030]
[Table 2]

[0031]
Example 3
High ash high quality printed waste paper (mainly ash content 31.9%) consisting mainly of coated paper containing ash content of 30% or more is charged into a pulper, the raw material concentration is 15%, sodium hydroxide addition rate is 0.3% of pulp %, The disaggregation time was 15 minutes, and the disaggregation temperature was 35 ° C. (disaggregation step). The disaggregated raw material after the disaggregation was diluted to 3.8% (dilution step), and then introduced into an ash removal device (fall washer: manufactured by Eiko) and concentrated to a raw material concentration of 7.8% (ash removal step). The filtrate of the ash removal device was treated with a white water treatment device (Poseidon Saturn: manufactured by Aikawa Tekko Co., Ltd.) to obtain treated water with a solid content concentration of 0.1%.
The obtained treated water was used as dilution water in the disintegration process of waste paper, dilution water in the dilution process of the disaggregation raw material after disaggregation, washing water in the ash removal apparatus in the ash removal process, and washing water in the deinking pulp manufacturing process described later. .
[0032]
The pulp slurry after ash removal was diluted to 3% and then processed at a deinking pulp manufacturing facility (existing recycled paper pulp manufacturing facility at Oji Paper Kasugai Mill) to produce a product pulp. The bleaching conditions were hydrogen peroxide addition rate to pulp 3.0%, sodium hydroxide to pulp addition rate 2.4%, sodium silicate addition rate to pulp sodium hydroxide equivalent 0.8%, pulp concentration 30%, bleaching time It was carried out at a bleaching temperature of 68 ° C. for 2 hours and 30 minutes. The deinking conditions were as follows: the concentration of the flotator treatment was 1.4%, the flotation treatment temperature was 44 ° C, and the deinking agent addition rate was 0.25%. As the deinking agent, a fatty acid-based deinking agent, a fatty acid-based deinking agent “DI-1050” (trade name: manufactured by Kao Corporation) was used.
[0033]
Comparative Example 3
High ash high quality printed waste paper (mainly ash content 31.9%) consisting mainly of coated paper containing ash content of 30% or more is charged into a pulper, the raw material concentration is 15%, sodium hydroxide addition rate is 0.3% of pulp %, The disaggregation time was 15 minutes, and the disaggregation temperature was 35 ° C. (disaggregation step). The disaggregated raw material after the disaggregation is diluted to 3.8% (dilution step), the pulp slurry is diluted to 3%, and the same existing deinked pulp production equipment as in Example 2 (the existing recycled paper pulp of Oji Paper Kasugai Mill) The product pulp was produced by processing at the production facility. Bleaching conditions and deinking conditions were the same as in Example 3.
The above results are shown in Table 3.
[0034]
[Table 3]

[0035]
【The invention's effect】
As shown in Tables 1, 2 and 3, according to the present invention, the ash content of the product pulp is reduced by 1.2 to 2.2% by removing the ash content after disaggregation, and the product pulp whiteness is 3. It rose by 5 to 3.8%. The basic unit of washing water could be reduced by 22 to 60 m ³ / ADT, and the ratio could be reduced by 18 to 44%.

Claims

The step of macerating the high ash printed waste paper containing 15～35Wt% in the total solid content of ash, dilution step for diluting the waste paper suspension was macerated in the raw material concentration 2～4Wt%, and a stock suspension was diluted stock It is introduced into a drum-type ash removal device having an inlet zone, a displacement washing zone, and a finishing zone to remove ash preferentially, and the raw material concentration is filtered and concentrated to 5 to 9 wt% to remove the ash from 7 to Removed from high-ash printed waste paper, characterized by having an ash removal process that reduces to 25 wt% and a deinked pulp manufacturing process that processes the raw material obtained from the ash removal process in the order of dust removal, hydrogen peroxide bleaching, and deinking. A method for producing black pulp.

The method further comprises a filtrate treatment step of treating the ash-containing filtrate generated in the ash removal step to obtain a low solid concentration filtrate having a solid concentration of 0.1 wt% or less, and the low solid concentration filtrate is 2. The deinking process from the high ash printed waste paper according to claim 1, wherein the dewatering process, the diluting process, the ash removing process, and the deinked pulp manufacturing process are circulated and used as dilution water and / or washing water. A method for producing pulp.

3. The method for producing deinked pulp from high-ash printed waste paper according to claim 2, wherein the filtrate treatment step is a step of floating and separating solids in the ash-containing filtrate generated in the ash removal step. "