JPH05279978A - Bleaching of lignocellulose substance - Google Patents
Bleaching of lignocellulose substanceInfo
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- JPH05279978A JPH05279978A JP10240192A JP10240192A JPH05279978A JP H05279978 A JPH05279978 A JP H05279978A JP 10240192 A JP10240192 A JP 10240192A JP 10240192 A JP10240192 A JP 10240192A JP H05279978 A JPH05279978 A JP H05279978A
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- pulp
- chlorine
- bleaching
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- bleached
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、リグノセルロース物質
の漂白方法に関する。さらに詳しく述べれば、本発明
は、リグノセルロース物質から得られるパルプを塩素漂
白を含む多段漂白シーケンスで漂白する際に、該パルプ
を塩素漂白に先立ち塩素漂白段からのろ液を混合して処
理した後前記多段漂白する方法に関する。FIELD OF THE INVENTION The present invention relates to a method for bleaching lignocellulosic material. More specifically, the present invention relates to treating pulp obtained from a lignocellulosic material by bleaching the pulp from a chlorine bleaching stage prior to chlorine bleaching when bleaching it in a multi-stage bleaching sequence including chlorine bleaching. The present invention also relates to the method for multi-stage bleaching.
【０００２】[0002]
【従来技術】リグノセルロース物質を多くの用途に使用
するためには、蒸解のような化学的作用によってリグノ
セルロース物質をパルプとした後、或いは機械的作用に
よってパルプとした後、さらに該パルプを漂白して白色
度を高める必要がある。例えば、クラフトパルプは、包
装資材のように強度を必要とする用途に使う場合を除い
て、通常、塩素、次亜塩素酸塩（ハイポ）、二酸化塩
素、酸素、過酸化水素、苛性ソーダ等の漂白剤及び漂白
助剤により漂白して、未晒パルプの着色原因物質である
残留リグニン等を除去した後に使用されるのが一般的で
ある。BACKGROUND OF THE INVENTION In order to use a lignocellulosic material for many purposes, the lignocellulosic material is made into a pulp by a chemical action such as digestion, or is made into a pulp by a mechanical action, and then the pulp is bleached. It is necessary to increase the whiteness. For example, kraft pulp is usually bleached with chlorine, hypochlorite (hypo), chlorine dioxide, oxygen, hydrogen peroxide, caustic soda, etc., except when it is used for applications requiring strength such as packaging materials. It is generally used after bleaching with a bleaching agent and a bleaching aid to remove residual lignin, which is a coloring-causing substance of unbleached pulp.
【０００３】強度を要求される化学パルプの漂白におい
ては、パルプの繊維自体の強度を高く保つために、炭水
化物（セルロース等）の分解におよぼす影響を最小にす
るように、過激な一段の漂白を避け、温和に漂白剤と漂
白条件を変えていく多段漂白工程（シーケンス）を採る
のが一般的である。In the bleaching of chemical pulp requiring strength, in order to keep the strength of the pulp fiber itself high, a radical one-step bleaching is performed so as to minimize the influence on the decomposition of carbohydrates (such as cellulose). It is common to avoid this and use a multi-stage bleaching process (sequence) that gently changes the bleaching agent and the bleaching conditions.
【０００４】通常、多段漂白シーケンスにおいては、最
初に塩素でパルプ中に含有されるリグニンを塩素化し、
リグニンに可溶性を付加した後、次にアルカリでリグニ
ンを溶解抽出して、パルプからリグニンを分離する。そ
の後さらに、次亜塩素酸塩、二酸化塩素等を用いて、残
留する少量のリグニンを分解除去し、白色度の高いパル
プを得る。Usually, in a multi-stage bleaching sequence, the lignin contained in the pulp is first chlorinated with chlorine,
After solubilizing the lignin, the lignin is then dissolved and extracted with alkali to separate the lignin from the pulp. After that, a small amount of residual lignin is decomposed and removed using hypochlorite, chlorine dioxide or the like to obtain a pulp with high whiteness.
【０００５】塩素処理を（Ｃ）、アルカリ処理を
（Ｅ）、次亜塩素酸塩処理を（Ｈ）、二酸化塩素処理を
（Ｄ）、過酸化水素処理を（Ｐ）として表わすと、これ
らの漂白剤を組み合わせた漂白シーケンスとしては、使
用する漂白剤および／または漂白助剤の順序に従い、Ｃ
−Ｅ−Ｈ−Ｅ−Ｄ、Ｃ−Ｅ−Ｄ−Ｅ−Ｄ、Ｃ−Ｅ−Ｈ−
Ｐ−Ｄ等をもっとも一般的なものとして挙げることがで
きる。Chlorine treatment is represented by (C), alkali treatment is represented by (E), hypochlorite treatment is represented by (H), chlorine dioxide treatment is represented by (D), and hydrogen peroxide treatment is represented by (P). As a bleaching sequence in which bleaching agents are combined, C
-E-H-E-D, C-E-D-E-D, C-E-H-
PD and the like can be mentioned as the most general ones.
【０００６】通常、ハンター白色度で80〜90％の完全漂
白パルプを得るには、5 段或いは6段の漂白段が必要で
あったが、近年塩素段では、塩素と二酸化塩素を併用す
る塩素化の方法、即ち、Ｃ／Ｄ、ＣD 或いはＤc 等の方
法、或いは塩素段に続くアルカリ抽出段においては、酸
素（Ｅo ）、又は過酸化水素（Ｅp ）又は次亜塩素酸塩
（ＥH ）或いはそれらを同時に併用する（例えばＥpo
）技術が開発されたこと、さらには酸素漂白技術との
組合せ等によって、漂白段を３段ないし４段に短縮出来
るようになった。Usually, in order to obtain a fully bleached pulp having a Hunter whiteness of 80 to 90%, 5 or 6 bleaching stages were required. In recent years, however, in chlorine stages, chlorine and chlorine dioxide are used in combination. In the method of oxidization, that is, the method such as C / D, C D or Dc, or the alkali extraction stage subsequent to the chlorine stage, oxygen (Eo), hydrogen peroxide (Ep) or hypochlorite (E H) is used. ) Or using them together (eg Epo
) Technology has been developed, and in combination with oxygen bleaching technology, the bleaching stage can be shortened to 3 or 4 stages.
【０００７】その例として、1986 Pulping Coference P
roceedings、153頁,167頁,489頁及び491 頁には、Ｃ／Ｄ
−ＥPO−Ｄ、Ｃ／Ｄ−ＥPO−Ｄ−Ｐ、Ｏ2 −Ｃ／Ｄ−Ｅ
O −Ｄ及びＣD −Ｅo −Ｄ等のシーケンスが、1987 Pul
ping Coference Proceedings15 頁にはＣ−Ｅo −Ｈ−
Ｐ、ＣD −Ｅo −Ｈ−Ｄ、Ｃ−Ｅo −Ｈ−Ｈ等のシーケ
ンスが提案され、一部のシーケンスは実機で稼働してい
る。As an example, 1986 Pulping Coference P
roceedings, pages 153, 167, 489 and 491, C / D
-E PO -D, C / D-E PO -D-P, O 2 -C / D-E
Sequence such as O -D and C D -Eo -D is, 1987 Pul
ping Coference Proceedings Page 15 has C-Eo-H-
P, C D -Eo -H-D , the sequence of such C-Eo -H-H have been proposed and some of the sequence is running real machine.
【０００８】最近、漂白排水中に含まれる有機塩素化合
物、例えばジベンゾ- パラ- ジオキサン（通称ダイオキ
シン）などの毒性が問題にされている。ダイオキシンの
人体に対する影響は、まだ明らかにされているわけでは
ないが、有機塩素化合物を削減するため、種々の方法が
採用されている。Recently, the toxicity of organic chlorine compounds contained in bleaching wastewater, such as dibenzo-para-dioxane (commonly called dioxins), has been a problem. Although the effects of dioxins on the human body have not yet been clarified, various methods have been adopted to reduce the amount of organic chlorine compounds.
【０００９】最近開発された修正連続蒸解（Modified C
ontinuous Cooking 、以下MCC と称する）法は、木材チ
ップをクラフト法で蒸解する際に、1)蒸解中にアルカリ
濃度を比較的均一にする、2)特に脱リグニンが最も進行
する段階の初期において、水硫化イオン（ＳＨ- ）濃度
をできるだけ高くする、3)特に、蒸解後期において、蒸
解液中に存在する溶解リグニン濃度を低くする、4)蒸解
初期及び後期において温度を低くする等によって、パル
プ品質の指標となるパルプ粘度は、通常のクラフト蒸解
から得られるパルプ並の水準においてリグニン量が30％
程度少ない未晒パルプを製造することができる（1987 P
ulping Coference Proceedings,P249 ）。[0009] Recently developed Modified C
ontinuous Cooking (hereinafter referred to as MCC) method, when cooking wood chips by the craft method, 1) to make the alkali concentration relatively uniform during cooking, 2) especially in the early stage of the stage where delignification is most advanced, Pulp quality by increasing the hydrosulfide ion (SH-) concentration as much as possible, 3) reducing the concentration of dissolved lignin existing in the cooking liquor, especially in the latter half of the cooking, and 4) lowering the temperature in the early and later stages of cooking. The pulp viscosity, which is an index of, is 30% of the lignin content at the same level as the pulp obtained from ordinary kraft cooking.
It is possible to produce a small amount of unbleached pulp (1987 P
ulping Coference Proceedings, P249).
【００１０】その結果、漂白段に持ち込まれるパルプ中
の残留リグニン量は減少しているので、漂白排水の汚濁
負荷量、とりわけ有機塩素の排出量を通常より大幅に低
減できるといわれている（EUCEPA Symposium preprints
p16 (1980), Paperi yaa Puu 65(4):227(1983),Tappi
J.66(9):97(1983) ）。As a result, the amount of residual lignin in the pulp brought into the bleaching stage is reduced, and it is said that the pollution load amount of bleaching wastewater, especially the emission amount of organic chlorine, can be significantly reduced compared to usual (EUCEPA Symposium preprints
p16 (1980), Paperi yaa Puu 65 (4): 227 (1983), Tappi
J. 66 (9): 97 (1983)).
【００１１】また、近年開発された酸素漂白法は、未晒
パルプのリグニン量をほぼ半減できるので、その後に続
く塩素段での塩素添加率を一層減少させることができ、
その結果排水中に含まれる有機塩素化合物の量も低減で
きる。そのため、わが国も含め世界の紙パルプを製造す
る主要国において多数の酸素漂白装置が稼働しており、
今後益々稼働数が増加するものと予想されている。In addition, the oxygen bleaching method developed in recent years can reduce the amount of lignin in unbleached pulp by almost half, so that the chlorine addition rate in the subsequent chlorine stage can be further reduced,
As a result, the amount of organic chlorine compounds contained in the waste water can be reduced. Therefore, a large number of oxygen bleaching devices are operating in major countries that manufacture paper pulp in the world, including Japan,
It is expected that the number of operating units will increase more and more in the future.
【００１２】前記した酸素漂白法（Ｏ2 段）は、従来の
塩素系の漂白法と組み合わされ、完全漂白パルプのみな
らず、半晒パルプの製造に応用されている。例えば、特
公昭47-7202 号公報にはＯ2 −Ｃ／Ｄ−Ｅの漂白シーケ
ンスが、特公昭47-10241号公報にはＣ／Ｄ−Ｏ2 −Ｄ−
Ｅ−Ｄの漂白シーケンスが、特公昭47-44441号公報には
Ｏ2 −Ｄc −Ｏ2 −Ｅの漂白シーケンスが、特公昭51-1
7605号公報にはＯ2 −Ｄ／Ｃ−Ｅ−Ｄの漂白シーケンス
がそれぞれ提案されている。The above-mentioned oxygen bleaching method (O 2 stage) is combined with the conventional chlorine bleaching method and is applied not only to the completely bleached pulp but also to the semi-bleached pulp. For example, Japanese Patent Publication No. 47-7202 discloses an O 2 -C / DE bleaching sequence, and Japanese Patent Publication No. 47-10241 discloses C / D-O 2 -D-.
Bleaching sequence of E-D is the bleaching sequence O 2 -Dc -O 2 -E in JP-B-47-44441, JP-B-51-1
In Japanese Patent No. 7605, an O 2 -D / C-E-D bleaching sequence is proposed.
【００１３】さらに、漂白段に入るパルプの残留リグニ
ン量を大幅に減少させるためには、ＭＣＣ法による蒸解
と酸素漂白法（Ｏ2 段）を組み合わせる方法が考えられ
る。例えば1987 Pulping Coference Proceedings ,453
頁には、ＭＣＣ蒸解されたパルプを酸素漂白した後、Ｃ
／Ｄ−Ｅo −Ｄの３段で、白色度90％ISO の漂白パルプ
を得ることができ、塩素添加率を大幅に低減できたと述
べられている。Further, in order to greatly reduce the amount of residual lignin in the pulp entering the bleaching stage, a method of combining the digestion by the MCC method and the oxygen bleaching method (O 2 stage) can be considered. For example, 1987 Pulping Coference Proceedings, 453
The page shows MCC cooked pulp after oxygen bleaching and then C
It is stated that the bleached pulp having a whiteness of 90% ISO can be obtained in the three stages of / D-Eo-D, and the chlorine addition rate can be greatly reduced.
【００１４】また、ＭＣＣ蒸解を稼働している外国の工
場では、針葉樹パルプを酸素漂白した後、（ＣＤ）−Ｅ
−Ｄ−Ｅ−Ｄのシーケンスで白色度90％ISO の漂白パル
プを製造しているが、この方法により、有機塩素化合物
の量を2.4kg/ton パルプから1.6kg/ton パルプに低減で
きると報告されている（Svensk Papperstidn.87(10):30
(1984)453 頁、Oxgen Delignification Symposium Proc
eedings,88頁(1985)）。In a foreign factory operating MCC digestion, softwood pulp is bleached with oxygen and then (CD) -E.
-The production of bleached pulp with 90% whiteness ISO in the sequence of D-E-D. It is reported that this method can reduce the amount of organic chlorine compounds from 2.4kg / ton pulp to 1.6kg / ton pulp. (Svensk Papperstidn.87 (10): 30
(1984) p. 453, Oxgen Delignification Symposium Proc
eedings, page 88 (1985)).
【００１５】従来から酸素段において、パルプに残留す
るリグニン量の指標となるカッパー価を酸素段に受け入
れるパルプのカッパー価の半分以下にすると、パルプ粘
度が大幅に低下し、パルプ強度が著しく低下するので、
半分以上の脱リグニン量を酸素段で得ることは困難であ
った。Conventionally, in the oxygen stage, when the Kappa number, which is an index of the amount of lignin remaining in the pulp, is set to be less than half of the Kappa number of the pulp accepted in the oxygen stage, the pulp viscosity is significantly reduced and the pulp strength is significantly reduced. So
It was difficult to obtain more than half the delignification amount in the oxygen stage.
【００１６】しかしながら、酸素漂白段の前で二酸化窒
素を用いて前処理すると、酸素段での脱リグニン性が向
上することが報告されており、この方法は、まだ実機ス
ケールでは稼働していないが、パイロットプラントのテ
ストでは、通常の酸素漂白に較べてカッパー価を酸素漂
白前の36％に減少でき、有機塩素化合物の量を41％減少
できたと報告されている（紙と周辺技術、季刊１号、198
8 ）。However, it has been reported that the pre-treatment with nitrogen dioxide before the oxygen bleaching stage improves the delignification property in the oxygen stage, and this method has not been operated on an actual scale yet. In a pilot plant test, it was reported that the Kappa number could be reduced to 36% before oxygen bleaching and the amount of organic chlorine compounds could be reduced by 41% compared to normal oxygen bleaching (paper and peripheral technology, quarterly 1 Issue, 198
8).
【００１７】ところが、この前処理法は、毒性のある二
酸化窒素を使う点に問題がある。また酸素漂白の前段
に、亜硫酸或いは硫酸で前処理すると、二酸化窒素前処
理と同様に酸素段での脱リグニン性が向上することも報
告されている（「 The Bleaching of Pulp 」 3rd Editio
n TAPPI PRESS 、177 頁）。しかしながらこの方法も、
硫黄バランスの関係で排酸を回収ボイラー送りとして系
内に回収することが困難なためほとんど実用化されてい
ない。However, this pretreatment method has a problem in using toxic nitrogen dioxide. It has also been reported that pretreatment with sulfurous acid or sulfuric acid prior to oxygen bleaching improves delignification in the oxygen stage, similar to nitrogen dioxide pretreatment ("The Bleaching of Pulp" 3rd Editio).
n TAPPI PRESS, p. 177). However, this method also
Due to the balance of sulfur, it is difficult to collect waste acid in the system as a recovery boiler feed, so it has not been practically used.
【００１８】塩素段で塩素添加率を低下させる方法とし
ては、塩素段で二酸化塩素を併用し、その使用比率を増
加させることを挙げることができる。近年、わが国のパ
ルプ製造工場では、二酸化塩素の使用比率を増加させて
操業されている例が多く報告されているが、工場の既設
の設備で二酸化塩素を発生させる能力には限度があり、
必要な二酸化塩素の量が限定されること、及び二酸化塩
素の製造コストが高いことから、塩素に対して30％以上
の二酸化塩素の使用比率に増加させることは経済的では
ない。As a method of reducing the chlorine addition rate in the chlorine stage, it is possible to use chlorine dioxide in combination in the chlorine stage and increase the use ratio thereof. In recent years, many pulp mills in Japan have been reported to operate with an increased proportion of chlorine dioxide used, but there is a limit to the ability of the existing facilities of the mill to generate chlorine dioxide,
Due to the limited amount of chlorine dioxide required and the high production cost of chlorine dioxide, it is not economical to increase the use ratio of chlorine dioxide to 30% or more with respect to chlorine.
【００１９】また、塩素段での塩素添加率を減少させ、
塩素段での脱リグニン不足を補うため、次のアルカリ抽
出段で、酸素（ＥO ）、過酸化水素（ＥP ）、ハイポ
（ＥH） 等のいずれかを併用する方法があるが、酸素
を使う場合には、パルプとの混合が重要なため特殊なミ
キサーが必要であり、過酸化水素は高価であり、ハイポ
の場合には、粘度低下が大きくなるという欠点がある。Further, the chlorine addition rate in the chlorine stage is reduced,
In order to compensate for the lack of delignification in the chlorine stage, there is a method of using oxygen (E O ), hydrogen peroxide (E P ), hypo (E H ), etc. together in the next alkali extraction stage. When using, a special mixer is required because mixing with pulp is important, hydrogen peroxide is expensive, and in the case of hypo, there is a drawback that the viscosity decrease becomes large.
【００２０】したがって簡便な方法で、塩素添加率をさ
らに減少し得る方法、言い替えれば、簡単な前処理によ
って、塩素段での脱リグニン性を一層向上させる方法が
望まれている。Therefore, there is a demand for a simple method capable of further reducing the chlorine addition rate, in other words, a method for further improving the delignification property in the chlorine stage by a simple pretreatment.
【００２１】[0021]
【発明が解決しようとする課題】本発明者等は、前記し
た問題点について鋭意検討した結果、リグノセルロース
物質から得られたパルプを多段漂白するに際し、塩素漂
白に先立ち塩素漂白段からのろ液を用いて特定されたpH
及び温度においてパルプを前処理した後に塩素漂白する
と塩素段での脱リグニン性が著しく向上するという驚く
べき事実を見出し、本発明を完成するに至った。DISCLOSURE OF THE INVENTION The inventors of the present invention have diligently studied the above-mentioned problems, and as a result, when bleaching pulp obtained from a lignocellulosic material in multiple stages, prior to chlorine bleaching, filtrate from the chlorine bleaching stage is used. PH specified using
The present inventors have completed the present invention by finding the surprising fact that chlorine bleaching after pretreatment of pulp at temperature and temperature significantly improves delignification in the chlorine stage.
【００２２】この結果、塩素段での塩素添加率を減少さ
せることができるので、排水中の有機塩素化合物の量を
大幅に低減できる。即ち、本発明は、塩素漂白段での脱
リグニンが向上するので、各漂白段での薬品添加率或い
はとりわけ塩素段での薬品添加率を通常の漂白法の水準
以下に下げても、通常の漂白法並のパルプ白色度を得る
ことが出来、薬品コストの低減ができる。また、塩素段
での薬品添加率を下げた場合、排水中への有機塩素化合
物の量を減少できる他に、漂白パルプの退色性も改善で
き、パルプの強度も向上できる。またＭＣＣ蒸解法との
組み合わせ、通常のクラフト法と酸素漂白法の組合せ、
或いはＭＣＣ蒸解法と酸素漂白法との組合せによって得
られるリグノセルロース物質からのパルプをを本発明に
よって漂白する場合には、排水への汚濁負荷量がもっと
も減少するばかりではなく、塩素段からの塩素化合物の
排出量自体が減少するので、排水の質の面でも大きく改
善され、さらにパルプ白色度の向上、薬品添加率の大幅
な低減が具現化可能となる。As a result, since the chlorine addition rate in the chlorine stage can be reduced, the amount of organic chlorine compounds in the waste water can be greatly reduced. That is, the present invention, since delignification in the chlorine bleaching stage is improved, even if the chemical addition rate in each bleaching stage or especially the chemical addition rate in the chlorine stage is lowered below the level of the ordinary bleaching method, Pulp whiteness comparable to that of the bleaching method can be obtained, and chemical costs can be reduced. Further, when the chemical addition rate in the chlorine stage is lowered, the amount of the organic chlorine compound in the waste water can be reduced, and the bleaching pulp can be improved in the discoloring property and the pulp strength can be improved. In addition, combination with MCC cooking method, combination of ordinary craft method and oxygen bleaching method,
Alternatively, when the pulp from the lignocellulosic material obtained by the combination of the MCC cooking method and the oxygen bleaching method is bleached according to the present invention, not only is the pollution load on the wastewater reduced most, but the chlorine from the chlorine stage is also reduced. Since the discharge amount of the compound itself is reduced, the quality of the waste water is greatly improved, and further, the whiteness of the pulp is improved and the chemical addition rate is significantly reduced.
【００２３】従って、本発明の目的は、排水汚濁負荷が
少なく、薬品添加率が低減でき、強度と退色性が向上し
た漂白パルプを製造し得る漂白法を提供することにあ
る。Therefore, it is an object of the present invention to provide a bleaching method capable of producing a bleached pulp which has a low wastewater pollution load, a reduced chemical addition rate, and improved strength and discoloration.
【００２４】[0024]
【発明が解決するための手段】本発明は、リグノセルロ
ース物質より得られたパルプを塩素、苛性ソーダ、次亜
塩素酸塩（ハイポ）、二酸化塩素、酸素、過酸化水素か
らなる多段漂白シーケンスの組合せにより漂白する方法
において、塩素漂白に先立ち塩素漂白段からのろ液を用
いて該パルプをpH2 〜5 の範囲及び温度40〜80℃の範囲
に維持して混合保持した後、洗浄、脱液することなく、
前記多段漂白シーケンスの塩素段で漂白することを特徴
とするリグノセルロース物質の漂白方法である。DISCLOSURE OF THE INVENTION The present invention provides a combination of a pulp obtained from a lignocellulosic material with a multi-stage bleaching sequence consisting of chlorine, caustic soda, hypochlorite (hypo), chlorine dioxide, oxygen and hydrogen peroxide. In the method of bleaching by means of the method described above, the pulp from the chlorine bleaching stage is used to maintain the pH in the range of pH 2 to 5 and the temperature in the range of 40 to 80 ° C. while mixing and holding, followed by washing and deliquoring. Without
A method for bleaching a lignocellulosic material, which comprises bleaching in a chlorine stage of the multi-stage bleaching sequence.
【００２５】本発明で用いられるリグノセルロース物質
は、通常のクラフトパルプ（ＫＰ）、アルカリパルプ
（ＡＰ）、サルファイトパルプ（ＳＰ）等の化学パルプ
は勿論、修正連続蒸解（ＭＣＣ）法で得られたアルカリ
性パルプ、通常のクラフト法で蒸解後、酸素漂白された
パルプ、及び前記ＭＣＣ法で蒸解後、酸素漂白された化
学パルプのいずれでも良い。更には木材（針葉樹及び広
葉樹）パルプ、非木材パルプのいずれにも適用可能であ
ることは言うまでもない。The lignocellulosic material used in the present invention can be obtained by a modified continuous cooking (MCC) method as well as ordinary chemical pulp such as kraft pulp (KP), alkaline pulp (AP) and sulfite pulp (SP). The alkaline pulp, the pulp that has been digested by the ordinary Kraft method and then oxygen-bleached, and the chemical pulp that has been digested by the MCC method and then oxygen-bleached may be used. Further, it goes without saying that it can be applied to both wood (softwood and hardwood) pulp and non-wood pulp.
【００２６】本発明の、塩素段で使われる塩素化合物
は、塩素および二酸化塩素で、それらは単独或いは任意
の割合で併用して使用できる。塩素段における塩素と二
酸化塩素の添加方法は、両者を混合しても良く、二酸化
塩素添加後数秒以内に塩素を添加してもよい。また二酸
化塩素の一部を添加し、その後二酸化塩素の残りと塩素
を混合し添加してもよい。The chlorine compounds used in the chlorine stage of the present invention are chlorine and chlorine dioxide, which can be used alone or in combination at any ratio. Regarding the method of adding chlorine and chlorine dioxide in the chlorine stage, both may be mixed, or chlorine may be added within a few seconds after the addition of chlorine dioxide. Alternatively, a part of chlorine dioxide may be added, and then the rest of chlorine dioxide and chlorine may be mixed and added.
【００２７】活性塩素量で表わされる塩素化合物の対絶
乾パルプ添加率は、未晒パルプ中に含有されるのリグニ
ン量に比例し、1 〜5 ％の範囲内で適宜選択して用いら
れる。塩素段における反応温度は30℃〜60℃の範囲、反
応時のパルプ濃度は1 〜10％の範囲、反応時間は5 〜60
分の範囲、終ｐＨは2 〜4 の範囲である。塩素段の漂白
工程が終了した後で、公知の方法によりパルプは洗浄と
脱水或いは圧縮が行なわれ、次の工程へ送られる。The addition rate of chlorine compounds to the absolute dry pulp, which is represented by the amount of active chlorine, is proportional to the amount of lignin contained in the unbleached pulp, and is appropriately selected and used within the range of 1 to 5%. The reaction temperature in the chlorine stage is in the range of 30 to 60 ° C, the pulp concentration during the reaction is in the range of 1 to 10%, and the reaction time is in the range of 5 to 60%.
The range of minutes, the final pH is in the range of 2-4. After the chlorine stage bleaching step is completed, the pulp is washed and dehydrated or compressed by a known method, and then sent to the next step.
【００２８】本発明の塩素段に先立ちパルプを前処理す
る工程で使われる液は、前記の塩素段からのろ液であ
り、この液に含まれる塩素化合物の種類は問わないが、
pHは2〜5 の範囲、好ましくは2 〜4 の範囲である。pH2
未満ではヘミセルロースのような多糖類が溶出し、セ
ルロースの一部が加水分解を受けるので繊維の損傷が発
生し、pHが5 を超えると脱リグニンを促進する効果がな
くなるので適さない。The liquid used in the step of pretreating pulp prior to the chlorine stage of the present invention is the filtrate from the above chlorine stage, and the kind of chlorine compound contained in this liquid is not limited,
The pH is in the range 2-5, preferably in the range 2-4. pH2
When it is less than the above value, polysaccharides such as hemicellulose are eluted and a part of the cellulose is hydrolyzed to cause fiber damage, and when the pH exceeds 5, the effect of promoting delignification is lost, which is not suitable.
【００２９】前処理工程における温度は、高いほど脱リ
グニンの促進の点では効果があるが、パルプの品質の点
から40〜80℃、好ましくは50〜60℃の範囲である。塩素
段を40℃以下の温度で操業している場合には、この塩素
段からのろ液を本発明のパルプの前処理工程に用いよう
とすれば、加温が必要である。しかしながら、今日、通
常の蒸解、洗浄工程を経てきた未晒パルプの温度は、一
般に40〜60℃の範囲にあり、更に、公知の酸素漂白法で
処理されたパルプの温度は、60〜80℃の範囲にあるの
で、前記前処理における温度を確保するにはスタートア
ップの時だけ加温が必要となる。温度が40℃未満では、
前処理を施した効果が得られにくくなるので、その場合
は加温をする必要があり、80℃を超える温度では、パル
プ品質の悪化並びに熱経済的にコスト高を招くので適さ
ない。The higher the temperature in the pretreatment step, the more effective it is in promoting delignification, but it is in the range of 40 to 80 ° C., preferably 50 to 60 ° C. from the viewpoint of pulp quality. When the chlorine stage is operated at a temperature of 40 ° C. or lower, heating is necessary if the filtrate from the chlorine stage is to be used in the pretreatment process of the pulp of the present invention. However, today, the temperature of unbleached pulp that has undergone the usual cooking and washing steps is generally in the range of 40 to 60 ° C, and the temperature of pulp treated by the known oxygen bleaching method is 60 to 80 ° C. Therefore, heating is required only at the time of start-up to secure the temperature in the pretreatment. At temperatures below 40 ° C,
Since it is difficult to obtain the effect of pretreatment, it is necessary to heat in that case, and a temperature of higher than 80 ° C. is not suitable because it deteriorates the pulp quality and increases the cost economically in a thermo-economic manner.
【００３０】前記前処理工程におけるパルプ濃度は、中
濃度乃至高濃度の範囲が望ましいが、濃度は高いほどパ
ルプ同士の接触が増加し、塩素段での脱リグニンを阻害
する成分が除去され易いが、濃度が高すぎると濾液とパ
ルプの混合が悪化しするので所望の効果が得られない。
また、パルプ濃度が低すぎても所望の効果が得られな
い。本発明における望ましいパルプ濃度は10〜20％の範
囲で、この中から適宜他の条件との組合せで選択して用
いられる。The pulp concentration in the pretreatment step is preferably in the range of medium to high concentration, but the higher the concentration, the more the contact between pulps increases, and the component that inhibits delignification in the chlorine stage is easily removed. However, if the concentration is too high, the desired effect cannot be obtained because the mixing of the filtrate and pulp deteriorates.
Further, even if the pulp concentration is too low, the desired effect cannot be obtained. The desirable pulp concentration in the present invention is in the range of 10 to 20%, and the pulp concentration is appropriately selected from these and used in combination with other conditions.
【００３１】さらに、前記前処理工程における保持時間
は、30〜120 分間である。保持時間が30分未満では反応
が十分でなく、120分を超える保持時間では、設備的に
コスト高を招くので適さない。この前処理段でのパルプ
のフローはアップフローでもダウンフローでも良い。本
発明ではこの前処理の後で混合接触させた液は除去しな
いで、即ち前処理を施したパルプは洗浄を行なうことな
く、続く塩素段に送られる。この工程で洗浄、脱液を行
うと、塩素段での漂白性が低下するばかりではなく、液
中に溶出したヘミセルロースのような多糖類がパルプ繊
維より外れて系外に排出されるので、収率が低下する欠
点もあり、洗浄、脱液をしてはならない。Further, the holding time in the pretreatment step is 30 to 120 minutes. If the holding time is less than 30 minutes, the reaction is not sufficient, and if the holding time is more than 120 minutes, the cost of the equipment is increased, which is not suitable. The pulp flow in this pretreatment stage may be upflow or downflow. In the present invention, the liquid mixed and contacted after the pretreatment is not removed, that is, the pretreated pulp is sent to the subsequent chlorine stage without washing. If washing and deliquoring are performed in this step, not only the bleaching property in the chlorine stage is deteriorated, but also polysaccharides such as hemicellulose eluted in the liquid are released from the pulp fiber and discharged out of the system. There is also the drawback of lowering the rate, so do not wash or drain.
【００３２】本発明の漂白系のアルカリ抽出段に使用さ
れるアルカリ及びその添加率は、公知のものから選ぶこ
とが出来る。アルカリとして苛性ソーダを用いる場合、
パルプ絶乾重量当りのアルカリ添加率は、NaOH表示で0.
5 〜3 ％の範囲である。The alkali used in the bleaching alkali extraction stage of the present invention and its addition rate can be selected from known ones. When using caustic soda as the alkali,
The alkali addition rate per absolute dry weight of pulp is 0 in NaOH display.
It is in the range of 5 to 3%.
【００３３】アルカリ抽出段で酸素を併用する場合は、
酸素ガス或いは酸素富化ガスのいずれも使用可能であ
り、公知の方法で加圧下または大気圧下で行わされる。
一般に酸素の添加率は、パルプの絶乾重量当り0.5 〜3
％の範囲である。反応温度は、40〜70℃の範囲、反応時
のパルプ濃度は、5 〜20％の範囲、反応時間は、30〜12
0 分の範囲、終ｐＨは、8 〜12 の範囲である。また、
過酸化水素或いはハイポをアルカリ抽出段で併用しても
良い。アルカリ抽出を終了したパルプは、その後公知の
方法で洗浄或いは圧縮脱液が行なわれ、続いて次の工程
へ送られる。When oxygen is also used in the alkali extraction stage,
Either oxygen gas or oxygen-enriched gas can be used, and it is performed under pressure or atmospheric pressure by a known method.
Generally, the oxygen addition rate is 0.5 to 3 per absolute dry weight of pulp.
% Range. The reaction temperature is in the range of 40 to 70 ° C, the pulp concentration during the reaction is in the range of 5 to 20%, and the reaction time is in the range of 30 to 12
The range of 0 minutes and the final pH are in the range of 8 to 12. Also,
Hydrogen peroxide or hypo may be used together in the alkali extraction stage. The pulp that has been subjected to the alkali extraction is then washed or dewatered by compression by a known method, and then sent to the next step.
【００３４】本発明の漂白系の次亜塩素酸塩（ハイポ）
段で使用される次亜塩素酸塩は、ナトリウム塩、カルシ
ュウム塩等の公知の次亜塩素酸塩から選ぶことができ、
次亜塩素酸塩の添加率は、パルプの絶乾重量当り0.1 〜
2 ％の範囲、反応温度は、30〜70℃の範囲、反応時のパ
ルプ濃度は3 〜20% の範囲、反応時間は、15〜200 分の
範囲であり、初期ｐＨは10前後が最適である。反応後公
知の方法で洗浄或いは圧縮脱液が行われる。Bleaching system hypochlorite (hypo) of the present invention
The hypochlorite used in the stage can be selected from known hypochlorites such as sodium salt and calcium salt,
The addition rate of hypochlorite is 0.1 ~ per dry weight of pulp.
2% range, reaction temperature is 30 ~ 70 ° C, pulp concentration during reaction is 3 ~ 20%, reaction time is 15 ~ 200 minutes, and initial pH is around 10. is there. After the reaction, washing or compression deliquoring is performed by a known method.
【００３５】本発明の漂白系の二酸化塩素段で使用され
る二酸化塩素は、公知の二酸化塩素発生法より得られる
二酸化塩素が用いられ、二酸化塩素の添加率は、二酸化
塩素換算でパルプの絶乾重量当り0.2 〜3 ％の範囲、反
応温度は、40〜90℃の範囲、反応時のパルプ濃度は、3
〜20％の範囲、反応時間は、15〜300 分の範囲である。
終ｐＨが2 〜6 の範囲に入るように補助アルカリを加え
ても良い。二酸化塩素段後は、前記の段と同様に公知の
方法で洗浄或いは圧縮脱液が行なわれる。As the chlorine dioxide used in the bleaching chlorine dioxide stage of the present invention, chlorine dioxide obtained by a known chlorine dioxide generation method is used, and the addition rate of chlorine dioxide is such that the pulp is completely dried in terms of chlorine dioxide. The range is 0.2 to 3% by weight, the reaction temperature is 40 to 90 ° C, and the pulp concentration during the reaction is 3
The reaction time is in the range of 15 to 300 minutes.
An auxiliary alkali may be added so that the final pH falls within the range of 2 to 6. After the chlorine dioxide stage, washing or compression deliquoring is performed by a known method as in the above stage.
【００３６】本発明の漂白方法は、単独の漂白工程とし
て行なうことが出来ることは勿論のこと、従来の漂白シ
ーケンスにおける工程の一部として代替してもよい。
尚、高い白色度のパルプを要求されない場合には、処理
工程が塩素段とアルカリ抽出段だけで良いことは言うま
でもない。The bleaching method of the present invention can of course be carried out as a single bleaching step, or may be replaced as a part of the steps in the conventional bleaching sequence.
Needless to say, when a pulp having a high whiteness is not required, the treatment step only needs to be a chlorine stage and an alkali extraction stage.
【００３７】[0037]
【実施例】以下に実施例を挙げて本発明をより具体的に
に説明するが、勿論本発明はこれによってなんら限定さ
れるものではない。 以下に示す実施例において、パル
プの漂白条件及びパルプの物理的性質の測定は、次の操
作手段によった。The present invention will be described in more detail with reference to the following examples, but of course the present invention is not limited thereto. In the examples shown below, the bleaching conditions of the pulp and the physical properties of the pulp were measured by the following operating means.
【００３８】（１）塩素段からのろ液による前処理 酸素漂白された広葉樹クラフトパルプ（国内材と外材の
混合材、混合比率50/50 ）の絶乾重量50ｇをプラスチッ
ク袋に採り、塩素段の濾液をパルプ濃度が15％になるよ
うに添加し、よく撹拌後50℃の恒温槽につけ、90分間保
持した。(1) Pretreatment with a filtrate from a chlorine stage An oxygen-bleached hardwood kraft pulp (mixed material of domestic and external materials, mixing ratio 50/50) was placed in a plastic bag with an absolute dry weight of 50 g, and the chlorine stage was used. The filtrate was added so that the pulp concentration would be 15%, stirred well, and placed in a constant temperature bath at 50 ° C. and kept for 90 minutes.
【００３９】（２）塩素漂白段 塩素段のろ液で前処理した後洗浄、脱液していないパル
プ、及び塩素段からのろ液で処理されていないパルプ絶
乾重量50ｇ夫々をプラスチック袋に採り、カッパー価に
比例（カッパー価×0.2 ％）した所定の有効塩素量（塩
素量と二酸化塩素量の総和）を加え、更にパルプ濃度が
10％になるように所定量の水を加え、よく撹拌後50℃の
恒温槽に浸漬し、30分間保持した。反応終了後試料を取
り出し、遠心脱水洗浄した。(2) Chlorine bleaching stage Pulp that has not been washed and deliquored after being pretreated with the filtrate of the chlorine stage and pulp that has not been treated with the filtrate from the chlorine stage with an absolute dry weight of 50 g is put in a plastic bag. The amount of effective chlorine (sum of chlorine and chlorine dioxide) proportional to the Kappa number (Kappa number x 0.2%) was added to the pulp concentration.
A predetermined amount of water was added so as to be 10%, well stirred, immersed in a constant temperature bath at 50 ° C., and kept for 30 minutes. After completion of the reaction, the sample was taken out and subjected to centrifugal dehydration washing.
【００４０】（３）アルカリ抽出段 遠心脱水洗浄したＣ段パルプをプラスチック袋に採り、
カッパー価に比例（カッパー価×0.1 ％）した所定のア
ルカリ量を加え、更にパルプ濃度が10％になるよう所定
量の水を加え、よく撹拌した後、パルプを袋から取出し
て2 リットル容量の縦型式オートクレーブの中へ袋から
取り出してパルプを入れ、60℃まで加温後酸素を1.5kg/
cm2 になるまで圧入した。10分間加圧下で撹拌した後、
大気圧まで減圧した後、更に50分間反応させた。反応終
了後試料を取り出し、遠心脱水洗浄した。(3) Alkali Extraction Stage Centrifugal dehydration washed C-stage pulp is put in a plastic bag,
Add a prescribed amount of alkali proportional to the kappa number (kappa number x 0.1%), and then add a prescribed amount of water so that the pulp concentration becomes 10%, mix well, remove the pulp from the bag, and remove Remove the pulp from the bag into the vertical type autoclave, put the pulp in it, and warm it to 60 ° C, then add 1.5 kg of oxygen.
Pressed until it reached cm2. After stirring under pressure for 10 minutes,
After reducing the pressure to atmospheric pressure, the reaction was continued for another 50 minutes. After completion of the reaction, the sample was taken out and subjected to centrifugal dehydration washing.
【００４１】（４）次亜塩素酸塩（ハイポ）段 遠心脱水洗浄したアルカリ抽出した後のパルプをプラス
チック袋に採り、次亜塩素酸ソーダを絶乾パルプ重量当
り0.3 ％添加し、初期ｐＨが9.5 〜10になるように所定
量のアルカリを添加し、更にパルプ濃度が10％になるよ
う所定量の水を加え、よく撹拌後45℃の恒温槽で、2 時
間保持した。反応終了後試料を取り出し、遠心脱水洗浄
した。(4) Hypochlorite (hypo) stage Centrifugal dehydration washed alkali-extracted pulp was put in a plastic bag, and sodium hypochlorite was added at 0.3% based on the weight of absolutely dry pulp, and the initial pH was adjusted. A predetermined amount of alkali was added so that the pulp concentration was 9.5 to 10, and further a predetermined amount of water was added so that the pulp concentration became 10%. After well stirring, the mixture was kept in a constant temperature bath at 45 ° C for 2 hours. After completion of the reaction, the sample was taken out and subjected to centrifugal dehydration washing.
【００４２】（５）二酸化塩素段 遠心脱水洗浄した次亜塩素酸塩段からのパルプをプラス
チック袋に採り、二酸化塩素基準でパルプの絶乾重量当
り0.3 ％の二酸化塩素を添加し、更にパルプ濃度が10％
になるよう所定量の水を加え、よく撹拌後70℃の恒温槽
で、3 時間保持した。反応終了後試料を取り出し、遠心
脱水洗浄した。(5) Chlorine dioxide stage Pulp from the hypochlorite stage that has been centrifugally dehydrated and washed is put in a plastic bag, and 0.3% of chlorine dioxide is added to the dry weight of pulp based on chlorine dioxide. Is 10%
A predetermined amount of water was added to the mixture so that it was well stirred, and the mixture was kept in a constant temperature bath at 70 ° C for 3 hours. After completion of the reaction, the sample was taken out and subjected to centrifugal dehydration washing.
【００４３】（６）パルプの物理的性質の測定 白色度：遠心脱水洗浄したパルプを、離解後Tappi 試験
法 T205os-71（JIS P 8209）に従って坪量250g/m2 の手
抄きシートを作製し、JIS P 8123に従って測定した。 粘度：遠心脱水洗浄したパルプを、手で細かくほぐした
後、Tappi 試験法 T 230に従って測定した。 裂断長及び比引裂き強さ：遠心脱水洗浄したパルプをPF
I ミルでフリーネス450ml （カナダ標準フリーネス）に
叩解し、前記と同様な方法によって坪量60g/ｍ2のシー
トを作製し、製紙用パルプの強さ試験法（JIS P 8123）
に従って測定した 。退色試験：漂白後のパルプを105 ℃の送風循環式恒温
槽で2 時間加熱して退色させた後、白色度の測定の場合
と同様に、JIS P 8123に従って退色前後の白色度を測定
し、クベルカ・ムンクの式に従って色戻り（ＰＣ価）を
算出した。 カッパー価：Scan試験法 C-1:77に従って測定した。(6) Measurement of Physical Properties of Pulp Whiteness: The pulp that had been dewatered by centrifugal separation was used to prepare a hand-made sheet having a basis weight of 250 g / m 2 according to Tappi test method T205os-71 (JIS P 8209) after disintegration. , JIS P 8123. Viscosity: Centrifugal dewatered and washed pulp was loosened by hand and then measured according to Tappi test method T230. Breaking length and specific tear strength: PF for pulp that has been centrifugally dehydrated and washed
It is beaten to 450 ml (Canada standard freeness) with an I mill, and a sheet with a basis weight of 60 g / m 2 is prepared by the same method as described above, and a strength test method for papermaking pulp (JIS P 8123).
Was measured according to. Discoloration test: After bleached pulp is heated for 2 hours in an air circulation type constant temperature bath at 105 ° C to discolor, the whiteness before and after discoloration is measured according to JIS P 8123, as in the case of whiteness measurement. Color reversion (PC value) was calculated according to the Kubelka-Munk equation. Kappa number: measured according to Scan test method C-1: 77.
【００４４】実施例１及び比較例１〜３ 実施例１及び比較例１〜３は、通常のクラフト法によっ
て蒸解し、その未晒パルプを酸素漂白した広葉樹クラフ
トパルプ（カッパー価：10.2、国内材：外材＝50:50 の
混合材）を４段で完全漂白した場合の実験を示す。実施
例１は、酸素漂白後のクラフトパルプを塩素段からのろ
液で温度50℃で前処理し、洗浄、脱液せずに続いて前記
した手法によりＣ−Ｅ／Ｏ−Ｈ−Ｄのシーケンスで漂白
した例であり、比較例１は、温度30℃で、比較例２は、
温度100 ℃で前記パルプをそれぞれ実施例１と同じく前
記ろ液で前処理し、洗浄、脱液せずに前記と同じ漂白シ
ーケンスで漂白した例である。また、比較例３は、同じ
酸素漂白した広葉樹クラフトパルプを塩素段からのろ液
で前処理せずに、実施例１と同じシーケンスで漂白した
例である。実施例１及び比較例１〜３で得られた結果を
表１に示す。Example 1 and Comparative Examples 1 to 3 In Example 1 and Comparative Examples 1 to 3, hardwood kraft pulp (kappa number: 10.2, domestic timber) prepared by digesting by a normal kraft method and bleaching the unbleached pulp with oxygen : External material = 50:50 mixed material) is an experiment when completely bleached in 4 steps. In Example 1, the kraft pulp after oxygen bleaching was pretreated with a filtrate from a chlorine stage at a temperature of 50 ° C., washed and not deliquored, and then the C / E / O-H-D product was obtained. It is an example of bleaching in a sequence, Comparative Example 1 is at a temperature of 30 ° C., and Comparative Example 2 is
In this example, the pulp was pretreated at the temperature of 100 ° C. with the filtrate as in Example 1 and was bleached in the same bleaching sequence as above without washing and deliquoring. Comparative Example 3 is an example in which the same oxygen bleached hardwood kraft pulp was bleached in the same sequence as in Example 1 without pretreatment with the filtrate from the chlorine stage. The results obtained in Example 1 and Comparative Examples 1 to 3 are shown in Table 1.
【００４５】[0045]
【表１】 [Table 1]
【００４６】実施例２及び比較例４〜６ 実施例２は、実施例１と同様に酸素漂白した広葉樹晒ク
ラフトパルプ（カッパー価：9.3 、国内材：国外材＝5
0:50 ）を用い、塩素段からのろ液を用いてｐＨ3.0 で
前処理し、洗浄、脱液せずに続いて前記した手法により
Ｃ−Ｅ／Ｏ−Ｈ−Ｄのシーケンスで漂白した例であり、
比較例４は、パルプの前処理をpH1.5 で行い、比較例５
は、パルプの前処理をpH6.0 で行い、それぞれ実施例２
と同じく前処理後洗浄、脱液をせずに前記と同じ漂白シ
ーケンスで漂白した例である。また、比較例６は、同じ
広葉樹クラフトパルプを実施例２と同じ条件で、塩素段
ろ液で前処理した後、充分に洗浄、脱液し、その後、実
施例２と同じシーケンスで漂白した例である。実施例２
及び比較例４〜６で得られた結果を表２に示す。Example 2 and Comparative Examples 4 to 6 In Example 2, as in Example 1, oxygen bleached hardwood bleached kraft pulp (kappa number: 9.3, domestic material: foreign material = 5) was used.
0:50) with a filtrate from the chlorine stage at a pH of 3.0, followed by washing and deliquoring, followed by bleaching in the C-E / O-H-D sequence by the procedure described above. Is an example of
In Comparative Example 4, the pulp was pretreated at pH 1.5, and Comparative Example 5 was used.
Was subjected to a pretreatment of pulp at pH 6.0, and each was treated in Example 2
Similarly to the above, this is an example of bleaching in the same bleaching sequence as described above without washing and deliquoring after pretreatment. Further, Comparative Example 6 is an example in which the same hardwood kraft pulp was pretreated with a chlorine stage filtrate under the same conditions as in Example 2, thoroughly washed and drained, and then bleached in the same sequence as in Example 2. Is. Example 2
Table 2 shows the results obtained in Comparative Examples 4 to 6.
【００４７】[0047]
【表２】 [Table 2]
【００４８】実施例３及び比較例７ 実施例３及び比較例７は、国内材と国外材（50:50)の混
合物をＭＣＣ法によってクラフト蒸解し、その未晒パル
プを酸素漂白して得られた広葉樹パルプ（カッパー価：
8.9)をＣ−Ｅ／Ｏ−Ｈ−Ｄのシーケンスで漂白した場合
の実験を示す。実施例３は、酸素漂白後のパルプを塩素
段からのろ液で前処理し、洗浄、脱液せずに漂白した
例、比較例７は、酸素漂白後のパルプを塩素段からのろ
液で前処理せずに漂白した例である。実施例３及び比較
例７で得られた結果を表３に示す。Example 3 and Comparative Example 7 Example 3 and Comparative Example 7 were obtained by kraft cooking a mixture of domestic wood and foreign wood (50:50) by the MCC method, and bleaching the unbleached pulp with oxygen. Hardwood pulp (Kappa number:
The experiment when 8.9) is bleached in the sequence of CE / OHD is shown. Example 3 is an example in which pulp after oxygen bleaching was pretreated with a filtrate from a chlorine stage and was bleached without washing and deliquoring. In Comparative Example 7, pulp after oxygen bleaching was filtered from a chlorine stage. This is an example of bleaching without pretreatment. The results obtained in Example 3 and Comparative Example 7 are shown in Table 3.
【００４９】[0049]
【表３】 [Table 3]
【００５０】表１〜表３から明らかな如く、本発明方法
は、塩素段における脱リグニンを促進するので、同じ薬
品添加率を用いると、クラフト法ー酸素漂白パルプ（実
施例１及び２）及びＭＣＣ法ー酸素漂白パルプ（実施例
３）ともパルプの白色度が高く仕上がり、退色性が著し
く改善され、パルプ粘度、パルプ強度（引張り強度及び
引裂強度）が向上する。それ故、二者択一的に、本発明
法では従来法からのパルプと同じ白色度及びパルプ強度
を有するパルプを得る場合、薬品使用量が大幅に減少で
きるので、薬品コストを低減できる。そして、この薬品
使用量の減少を塩素段に添加する塩素に限定すれば、排
水中への有機塩素化合物の量の発生を減少し得るので排
水の質を大きく改善することができる。As is apparent from Tables 1 to 3, since the method of the present invention promotes delignification in the chlorine stage, using the same chemical addition rate, Kraft process-oxygen bleached pulp (Examples 1 and 2) and The MCC method-oxygen bleached pulp (Example 3) has a high pulp whiteness and is finished, the fading property is significantly improved, and the pulp viscosity and pulp strength (tensile strength and tear strength) are improved. Therefore, in the alternative, in the method of the present invention, when a pulp having the same whiteness and pulp strength as the pulp from the conventional method is obtained, the amount of chemicals used can be significantly reduced, and the chemical cost can be reduced. If the reduction in the amount of chemicals used is limited to chlorine added to the chlorine stage, the generation of the amount of organic chlorine compounds in the wastewater can be reduced, so that the quality of the wastewater can be greatly improved.
【００５１】[0051]
【発明の効果】以上の説明から明らかなように、本発明
は従来法と比較して、パルプの白色度及び強度が優れ、
更に完全漂白パルプの場合は退色し難いパルプを得るこ
とができ、二者択一的に、同じ白色度のパルプとする
と、薬品使用量が大幅に減少するので、これを塩素段に
適用すれば、排水中への有機塩素化合物の量の排出を減
少し得る方法を提供するという効果を奏する。As is apparent from the above description, the present invention is superior in whiteness and strength of pulp as compared with the conventional method,
Furthermore, in the case of completely bleached pulp, it is possible to obtain a pulp that is difficult to discolor, and alternatively, if pulp with the same whiteness is used, the amount of chemicals used is greatly reduced. And, it is effective to provide a method capable of reducing the discharge of the amount of the organic chlorine compound into the waste water.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 内田 洋介 東京都江東区東雲１丁目10番６号 王子製 紙株式会社中央研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yosuke Uchida 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. Central Research Laboratory
Claims (1)
プを塩素、苛性ソーダ、次亜塩素酸塩（ハイポ）、二酸
化塩素、酸素、過酸化水素からなる多段漂白シーケンス
の組合せにより漂白する方法において、塩素漂白に先立
ち塩素漂白段からのろ液を用いて該パルプをｐＨ２〜５
の範囲及び温度40〜80℃の範囲に維持して混合保持した
後、洗浄、脱液することなく、前記多段漂白シーケンス
の塩素段で漂白することを特徴とするリグノセルロース
物質の漂白方法。1. A method of bleaching pulp obtained from a lignocellulosic material by a combination of a multi-step bleaching sequence consisting of chlorine, caustic soda, hypochlorite (hypo), chlorine dioxide, oxygen and hydrogen peroxide. Prior to this, the pulp was adjusted to pH 2-5 using the filtrate from the chlorine bleaching stage.
The method for bleaching a lignocellulosic substance, which comprises bleaching in a chlorine stage of the multistage bleaching sequence without washing and deliquoring after mixing and holding the mixture in the range and the temperature of 40 to 80 ° C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4102401A JP2812056B2 (en) | 1992-03-30 | 1992-03-30 | Method for bleaching lignocellulosic material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4102401A JP2812056B2 (en) | 1992-03-30 | 1992-03-30 | Method for bleaching lignocellulosic material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05279978A true JPH05279978A (en) | 1993-10-26 |
| JP2812056B2 JP2812056B2 (en) | 1998-10-15 |
Family
ID=14326429
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4102401A Expired - Fee Related JP2812056B2 (en) | 1992-03-30 | 1992-03-30 | Method for bleaching lignocellulosic material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2812056B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104179056A (en) * | 2013-05-23 | 2014-12-03 | 中国制浆造纸研究院 | Wheat straw pulp elemental-chlorine-free bleaching wastewater recycling method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57121691A (en) * | 1980-11-27 | 1982-07-29 | Mo Och Domsjoe Ab | Delignifying and/or bleaching of cellulose pulp |
| JPS6112992A (en) * | 1984-06-26 | 1986-01-21 | 新王子製紙株式会社 | Bleaching of lignocellulose substance |
-
1992
- 1992-03-30 JP JP4102401A patent/JP2812056B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57121691A (en) * | 1980-11-27 | 1982-07-29 | Mo Och Domsjoe Ab | Delignifying and/or bleaching of cellulose pulp |
| JPS6112992A (en) * | 1984-06-26 | 1986-01-21 | 新王子製紙株式会社 | Bleaching of lignocellulose substance |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104179056A (en) * | 2013-05-23 | 2014-12-03 | 中国制浆造纸研究院 | Wheat straw pulp elemental-chlorine-free bleaching wastewater recycling method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2812056B2 (en) | 1998-10-15 |
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