JPH0466954B2 - - Google Patents
Info
- Publication number
- JPH0466954B2 JPH0466954B2 JP59154470A JP15447084A JPH0466954B2 JP H0466954 B2 JPH0466954 B2 JP H0466954B2 JP 59154470 A JP59154470 A JP 59154470A JP 15447084 A JP15447084 A JP 15447084A JP H0466954 B2 JPH0466954 B2 JP H0466954B2
- Authority
- JP
- Japan
- Prior art keywords
- alkali
- unbleached pulp
- pulp
- washing
- added
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 claims description 35
- 239000003513 alkali Substances 0.000 claims description 29
- 238000005406 washing Methods 0.000 claims description 26
- 238000010411 cooking Methods 0.000 claims description 18
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- 239000007788 liquid Substances 0.000 claims description 11
- 239000002699 waste material Substances 0.000 claims description 8
- 239000002655 kraft paper Substances 0.000 claims description 6
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 5
- 238000004061 bleaching Methods 0.000 claims description 5
- 238000000926 separation method Methods 0.000 claims description 5
- 235000011121 sodium hydroxide Nutrition 0.000 claims description 5
- 239000000725 suspension Substances 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 3
- 229920001021 polysulfide Polymers 0.000 claims description 3
- 239000005077 polysulfide Substances 0.000 claims description 3
- 150000008117 polysulfides Polymers 0.000 claims description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 description 11
- 238000000354 decomposition reaction Methods 0.000 description 11
- 229920005610 lignin Polymers 0.000 description 11
- 150000008442 polyphenolic compounds Chemical class 0.000 description 11
- 235000013824 polyphenols Nutrition 0.000 description 11
- 239000000126 substance Substances 0.000 description 6
- 238000004140 cleaning Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 238000006073 displacement reaction Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 210000000988 bone and bone Anatomy 0.000 description 3
- 238000010790 dilution Methods 0.000 description 3
- 239000012895 dilution Substances 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 230000003749 cleanliness Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 239000007844 bleaching agent Substances 0.000 description 1
- 150000001720 carbohydrates Chemical class 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000011121 hardwood Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012978 lignocellulosic material Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Landscapes
- Paper (AREA)
Description
(A) 産業上の利用分野
本発明はアルカリ性蒸解未漂白パルプの洗浄度
を向上させる方法に関するものであり、更に詳し
くはアルカリ性蒸解未漂白パルプ中に残存する、
リグニン分解物、ポリフエノール類等の漂白剤消
費物質を減少させる方法に関するものである。
(B) 従来技術
従来、リグノセルロース物質の主脱リグニン工
程である蒸解工程で分解されたリグニン分解物や
ポリフエノール類等を分離する方法として、蒸解
に用いた薬剤の回収を兼ねて洗浄液による希釈と
置換、脱水等を組合わせた向流洗浄方法が用いら
れている。しかしこの方法では向流洗浄の最終段
の洗浄液として加温された水が用いられる為、リ
グニン分解物やポリフエノール類の水に対する溶
解度が低く、特にクラフト蒸解、ポリサルフアイ
ド蒸解、ソーダ蒸解等のアルカリ蒸解後のパルプ
では、洗浄の進行と共に系のPHが低下する為著し
く溶解度が低下し、リグニン分解物やポリフエノ
ール類の一部はパルプ繊維内に再吸着して除去が
不可能になる。このため従来技術に於いては、こ
れらの物質が漂白工程で漂白剤を消費し、又廃液
汚染度を増加させるという欠点を有していた。
(C) 発明の目的
本発明者は、蒸解廃液分離の為めの洗浄後のパ
ルプ繊維内に残留するリグニン分解物、ポリフエ
ノール類を除去する方法について検討した結果、
これらの物質がアルカリに対する溶解度の高いこ
とを利用して、未漂白パルプにアルカリを添加す
ることによつて、これら物質の大巾な除去効率の
向上が可能であることを見出し、本発明を完成す
るに到つた。
(D) 発明の構成
即ち、本発明は、アルカリ性蒸解後の未漂白パ
ルプに、アルカリ処理後のパルプ懸濁液のPHが
9.5以上になるようにアルカリを添加して、100℃
以下の温度で反応処理し、しかる後に洗浄脱水し
パルプ繊維内に残留するリグニン分解物、ポリフ
エノール類を除去する未漂白パルプの処理方法に
関するものである。
本発明は、凡ての未漂白パルプに適用可能であ
るが、洗浄工程でリグニン分解物やポリフエノー
ル類の再吸着が生じ易いアルカリ性蒸解パルプ、
即ち、クラフト法、ポリサルフアイド法、ソーダ
法、クラフト−アントラキノン法、ポリサルフア
イド−アントラキノン法、ソーダ−アントラキノ
ン法等の方法で製造された未漂白パルプに於いて
特に除去効果が大きく好ましい。
通常の向流洗浄工程では、洗浄の最終段の洗浄
液として温水が使用される為、洗浄度が上るに従
つて系のPHが低下し、リグニン分解物やポリフエ
ノール類の除去効率が低下してくる。
本発明は、リグニン分解物、ポリフエノール類
のアルカリによる溶解が重要な要素の１つであ
り、PHが高いほどフエノール性水酸基の解離は進
んでこれらの物質の抽出は容易になるが、未漂白
パルプのアルカリ処理後のPHが9.5位いからカツ
パー価（パルプ中のリグニン分解物、ポリフエノ
ル類の濃度はカツパー価（JISP8211−1976）に
ほぼ比例する。）の低下が大きくなる。より大き
なカツパー価低下の効果を得る為にはアルカリ処
理後のPH10以上が好ましい。
未漂白パルプに添加するアルカリは、反応後の
PHが9.5以上になるものが必要で、苛性ソーダ、
炭酸ソーダ、それらの混合物が使用可能であり、
アルカリ法パルプ化工程で得られる、白液、緑液
ならびにそれらの酸化物等の単独又は混合物も使
用可能で、その工場の状況に合せて添加するアル
カリを決めればよい。
反応はアルカリに対する溶解度と拡散によつて
支配されるので、温度が高い程反応速度は速い。
100℃の範囲で反応処理することが望ましく、100
℃以上では特殊な反応容器を必要とし、炭水化物
の崩壊が生じて収率が低下し、又加熱の為の熱源
を要するので100℃未満の温度で反応処理を実施
する。
本発明のアルカリ添加場所としては、アルカリ
性蒸解終了後の未漂白パルプであれば漂白工程前
のどの段階のパルプにも適用可能であり、例え
ば、蒸解廃液分離前の未漂白パルプに添加しても
よく、分離の為の向流洗浄機の第２段目及び／又
は第３段目の洗浄水、加圧置換洗浄機の置換洗浄
温水に添加してもよく、分離洗浄後のパルプに添
加して反応処理してもよいカツパー価の減少は、
短時間処理でも認められ、処理開始５分後には１
ポイントのカツパー価減少がみられるが、大きな
減少効果を得る為には15分以上、好ましくは30分
〜120分の帯留時間があればよく、その為め反応
容器を設けることが望ましい。
本発明は上記に示したケ所の１つにアルカリを
添加し、処理すれば、品質の低下を来たすことな
くカツパー価の減少効果は得られる。中でも好ま
しい方法は蒸解廃液分離後の未漂白パルプにアル
カリを添加し、反応容器で処理する方法であり、
より大きな効果を得ることが出来る。更に、本発
明は、アルカリの添加ケ所を複数にしてもよく、
例えば、廃液分離用の洗浄機の洗浄水と反応容器
にそれぞれアルカリを添加し処理してもよく、こ
の場合は単一ケ所の添加処理よりもより大きなカ
ツパー価の減少が得られる。
本発明の処理中のパルプ濃度は、特に制限は無
い。通常の黒液洗浄工程で用いられるドラム型洗
浄機の出口シート濃度、あるいは置換洗浄機の出
口濃度はいずれも10〜20％であるが、この濃度で
処理することが出来る。
又、添加するアルカリとの混合を容易にする為
に稀釈水を添加することも可能である。しかし過
度の稀釈はアルカリ添加率が上り不利となる。
逆に濃度を上げればアルカリ添加率は下がる
が、特殊な脱水機が必要となるので設備費の点で
不利となる。
従つて４〜20％更に好ましくは６〜20％が適当
である。
本発明処理後の洗浄は、通常のドラム型洗浄
機、又は置換洗浄機で行なうことが出来る。更に
処理後の洗浄によつて得られる液は、前工程で
ある向流式洗浄工程の洗浄水として用いることよ
り、最終的には回収ボイラーで燃焼させる。その
結果、添加したアルカリは緑液として回収され
る。
又、処理により溶出除去されたリグニン分解物
やポリフエノール類等の有機物は熱源として使用
される。
上記理由により次工程である漂白工程での有機
物の溶解抽出量が減少し、漂白工程の排水負荷が
低減する。
(E) 実施例
以下実施例によつて本発明を更に詳しく説明す
る。
実施例 １
国産広葉樹チツプを用い、液比2.7、活性アル
カリ添加率16％（Na2Oとして絶乾チツプ重量当
り）、最高温度170℃、保持時間45分でクラフト法
蒸解を得られた未漂白パルプを向流３段ドラムウ
オツシヤーで最終段洗浄水に50℃温水を用いて洗
浄した。洗浄後の未漂白パルプのカツパー価は
19.0で、パルプ付着水のPHは9.0であつた。
該パルプに苛性ソーダを0.2％、0.5％、1.0％、
1.5％（対パルプ絶乾重量％）をそれぞれ添加し、
濃度12％、温度80℃で30分反応処理した。処理後
のパルプ懸濁液のPHと、カツパー価を第１表に示
す。
比較例 １
苛性ソーダ添加率（対パルプ絶乾重量％）を０
％、0.1％とした他は、パルプのロツトを含め実
施例１と全て同じ処理をした、処理後のパルプ懸
濁液のPHと、カツパー価を第１表に示す。
(A) Industrial Application Field The present invention relates to a method for improving the cleanliness of alkaline-cooked unbleached pulp, and more specifically, the present invention relates to a method for improving the cleanliness of alkaline-cooked unbleached pulp.
This invention relates to a method for reducing bleach-consuming substances such as lignin decomposition products and polyphenols. (B) Prior art Conventionally, as a method for separating lignin decomposition products and polyphenols, etc., decomposed in the cooking process, which is the main delignification process of lignocellulosic materials, dilution with a washing liquid was used to also recover the chemicals used in cooking. A countercurrent cleaning method is used that combines water displacement, dehydration, etc. However, in this method, heated water is used as the washing liquid in the final stage of countercurrent washing, so the solubility of lignin decomposition products and polyphenols in water is low, especially in alkaline cooking such as kraft cooking, polysulfide cooking, and soda cooking. In the subsequent pulp, as the washing progresses, the pH of the system decreases, resulting in a significant decrease in solubility, and some of the lignin decomposition products and polyphenols are re-adsorbed within the pulp fibers, making it impossible to remove them. Therefore, in the prior art, these substances consumed bleaching agents in the bleaching process and also increased the degree of contamination of the waste liquid. (C) Purpose of the Invention The present inventor investigated a method for removing lignin decomposition products and polyphenols remaining in pulp fibers after washing for separating cooking waste liquid, and found that
Taking advantage of the high solubility of these substances in alkali, we discovered that by adding alkali to unbleached pulp, it was possible to greatly improve the removal efficiency of these substances, and completed the present invention. I came to the point. (D) Structure of the Invention That is, the present invention provides that unbleached pulp after alkaline cooking has a pH value of the pulp suspension after alkaline treatment.
Add alkali to 9.5 or higher and heat to 100℃
The present invention relates to a method for treating unbleached pulp, which involves reaction treatment at the following temperature, followed by washing and dehydration to remove lignin decomposition products and polyphenols remaining in the pulp fibers. The present invention is applicable to all unbleached pulps, but is applicable to alkaline pulps, which tend to re-adsorb lignin decomposition products and polyphenols during the washing process.
That is, it is particularly preferred because of its great removal effect on unbleached pulp produced by methods such as the Kraft method, polysulfide method, soda method, Kraft-anthraquinone method, polysulfide-anthraquinone method, and soda-anthraquinone method. In a normal countercurrent cleaning process, hot water is used as the final cleaning solution, so as the degree of cleaning increases, the pH of the system decreases, and the removal efficiency of lignin decomposition products and polyphenols decreases. come. In the present invention, dissolution of lignin decomposition products and polyphenols by alkali is one of the important factors. If the pH of the pulp after alkali treatment is around 9.5, the Katsupar number (the concentration of lignin decomposition products and polyphenols in the pulp is approximately proportional to the Katsupar number (JISP8211-1976)) will decrease significantly. In order to obtain a greater effect of reducing the Katsupar value, the pH after alkali treatment is preferably 10 or higher. The alkali added to unbleached pulp is
You need something with a pH of 9.5 or higher, such as caustic soda,
carbonated soda, mixtures thereof can be used,
White liquor, green liquor, and their oxides obtained in the alkaline pulping process can be used singly or in mixtures, and the alkali to be added may be determined depending on the conditions of the factory. Since the reaction is governed by solubility in alkali and diffusion, the higher the temperature, the faster the reaction rate.
It is desirable to carry out the reaction treatment in the range of 100℃.
If the temperature is higher than 100°C, a special reaction vessel is required, the carbohydrate collapses and the yield is reduced, and a heat source is required for heating, so the reaction treatment is carried out at a temperature below 100°C. The alkali addition site of the present invention can be applied to pulp at any stage before the bleaching process as long as it is unbleached pulp after alkaline cooking. For example, the alkali can be added to unbleached pulp before separation of cooking waste liquid. It is often added to the second and/or third stage washing water of a countercurrent washing machine for separation, the displacement washing hot water of a pressure displacement washing machine, and it can be added to the pulp after separation washing. The reduction in Katsupar number that may be treated by reaction is
It is observed even in short-term treatment, and 1% after 5 minutes of starting treatment.
Although a reduction in the Kuppar number of points is observed, in order to obtain a large reduction effect, a retention time of 15 minutes or more, preferably 30 minutes to 120 minutes is sufficient, and it is therefore desirable to provide a reaction vessel. In the present invention, by adding an alkali to one of the above-mentioned locations and performing the treatment, the effect of reducing the cut par value can be obtained without deteriorating the quality. Among these, the preferred method is to add alkali to the unbleached pulp after separating the cooking waste and treat it in a reaction vessel.
You can get a bigger effect. Furthermore, in the present invention, the alkali may be added at a plurality of locations,
For example, alkali may be added to the washing water of a washing machine for waste liquid separation and the reaction vessel for treatment, and in this case, a greater reduction in the Kuppar number can be obtained than when the alkali is added at a single point. There are no particular limitations on the pulp concentration during the treatment of the present invention. The sheet density at the exit of a drum-type washing machine or the density at the exit of a displacement washing machine used in a normal black liquor washing process is both 10 to 20%, and processing can be performed at this density. It is also possible to add dilution water to facilitate mixing with the alkali to be added. However, excessive dilution is disadvantageous as it increases the alkali addition rate. Conversely, if the concentration is increased, the alkali addition rate will be lowered, but a special dehydrator will be required, which is disadvantageous in terms of equipment costs. Therefore, a suitable amount is 4 to 20%, more preferably 6 to 20%. Cleaning after the treatment of the present invention can be carried out using a conventional drum-type washer or a displacement washer. Furthermore, the liquid obtained by washing after the treatment is used as washing water in the countercurrent washing step, which is the previous step, and is finally burned in a recovery boiler. As a result, the added alkali is recovered as green liquor. In addition, organic substances such as lignin decomposition products and polyphenols that are eluted and removed by the treatment are used as a heat source. For the above reasons, the amount of organic matter dissolved and extracted in the next bleaching step is reduced, and the wastewater load of the bleaching step is reduced. (E) Examples The present invention will be explained in more detail with reference to Examples below. Example 1 An unbleached product obtained by kraft cooking using Japanese hardwood chips with a liquid ratio of 2.7, an active alkali addition rate of 16% (as Na 2 O per bone dry chip weight), a maximum temperature of 170°C, and a holding time of 45 minutes. The pulp was washed in a countercurrent three-stage drum washer using 50°C hot water as the final washing water. The cut par value of unbleached pulp after washing is
19.0, and the pH of the water adhering to the pulp was 9.0. Add caustic soda to the pulp at 0.2%, 0.5%, 1.0%,
Add 1.5% (% by absolute dry weight of pulp),
The reaction was carried out at a concentration of 12% and a temperature of 80°C for 30 minutes. Table 1 shows the PH and Katsupar value of the pulp suspension after treatment. Comparative Example 1 Addition rate of caustic soda (absolute dry weight% of pulp) is 0
Table 1 shows the PH and cut par number of the pulp suspension after treatment, which was treated in the same manner as in Example 1, including the pulp lot, except that the pulp lot was changed to 0.1%.
【表】
本発明により、処理後のPHを9.5以上にするこ
とによつてカツパー価の低下が大きくなることが
解る。
実施例 ２
タスマニア産コーカリチツプを用い、液比３、
活性アルカリ添加率17％（Na2Oとして絶乾チツ
プ重量当り）、最高温度170℃、保持時間45分でク
ラフト法蒸解を行い未漂白パルプを得た。
結果を第２表に示す。
該未漂白パルプを用いて、パルプ濃度12％、苛
性ソーダ添加率1.0％、温度80℃で30分間処理し、
水洗した。得られたパルプの結果を第２表に示
す。
比較例 ２
実施例２と同一チツプを用い、液比３、活性ア
ルカリ添加率18.5％（Na2Oとして絶乾チツプ重
量当り）、最高温度170℃、保持時間45分でクラフ
ト法蒸解を行つた。得られた未漂白パルプの結果
を第２表に示す。[Table] According to the present invention, it can be seen that the reduction in the Katsupar value becomes greater by increasing the pH after treatment to 9.5 or higher. Example 2 Using Kokali chips from Tasmania, liquid ratio 3,
Unbleached pulp was obtained by Kraft cooking at an active alkali addition rate of 17% (as Na 2 O, based on the weight of bone dry chips), a maximum temperature of 170°C, and a holding time of 45 minutes. The results are shown in Table 2. The unbleached pulp was treated at a pulp concentration of 12%, a caustic soda addition rate of 1.0%, and a temperature of 80°C for 30 minutes,
Washed with water. The results of the obtained pulp are shown in Table 2. Comparative Example 2 Using the same chips as in Example 2, Kraft cooking was carried out at a liquid ratio of 3, an active alkali addition rate of 18.5% (as Na 2 O per bone dry chip weight), a maximum temperature of 170°C, and a holding time of 45 minutes. . The results for the unbleached pulp obtained are shown in Table 2.
【表】
〓注：粘度はパルプ中のセルロースの重
合度の指標で、処理中に繊〓
[Table] 〓Note: Viscosity is an indicator of the degree of polymerization of cellulose in the pulp.
Claims (1)
法、クラフト−アントラキノン法、ポリサルフア
イド−アントラキノン法、ソーダ−アントラキノ
ン法よりなる群から選ばれた蒸解法で蒸解終了し
た漂白工程前の未漂白パルプに、アルカリ処理後
のパルプ懸濁液のPHが9.5以上になるようにアル
カリを添加して100℃以下で処理し、しかる後洗
浄脱水することを特徴とする未漂白パルプの処理
方法。 ２ アルカリを、蒸解廃液を分離する洗浄装置を
通過した未漂白パルプに添加する特許請求の範囲
第１項記載の未漂白パルプの処理方法。 ３ アルカリを、蒸解廃液を分離する洗浄装置の
洗浄水に添加混合する特許請求の範囲第１項記載
の未漂白パルプの処理方法。 ４ アルカリを、蒸解廃液の分離前の未漂白パル
プに添加する特許請求の範囲第１項記載の未漂白
パルプの処理方法。 ５ 未漂白パルプに添加するアルカリが、苛性ソ
ーダ、炭酸ソーダ、白液、緑液、酸化白液、酸化
緑液の単独又は混合物である特許請求の範囲第１
項〜第４項記載の未漂白パルプの処理方法。[Scope of Claims] 1. Unbleached pulp before the bleaching process completed by a cooking method selected from the group consisting of the Kraft method, polysulfide method, soda method, Kraft-anthraquinone method, polysulfide-anthraquinone method, and soda-anthraquinone method. A method for treating unbleached pulp, which comprises adding an alkali so that the pH of the pulp suspension after alkali treatment is 9.5 or higher, treating at 100°C or less, and then washing and dewatering. 2. The method for treating unbleached pulp according to claim 1, wherein an alkali is added to the unbleached pulp that has passed through a washing device that separates cooking waste. 3. The method for treating unbleached pulp according to claim 1, wherein the alkali is added to and mixed with washing water of a washing device for separating cooking waste liquid. 4. The method for treating unbleached pulp according to claim 1, wherein an alkali is added to the unbleached pulp before separation of the cooking waste. 5. Claim 1, wherein the alkali added to the unbleached pulp is caustic soda, soda carbonate, white liquor, green liquor, oxidized white liquor, or oxidized green liquor alone or in a mixture.
A method for treating unbleached pulp according to items 4 to 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15447084A JPS6134296A (en) | 1984-07-25 | 1984-07-25 | Treatment of unbleached pulp |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15447084A JPS6134296A (en) | 1984-07-25 | 1984-07-25 | Treatment of unbleached pulp |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6134296A JPS6134296A (en) | 1986-02-18 |
| JPH0466954B2 true JPH0466954B2 (en) | 1992-10-26 |
Family
ID=15584949
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15447084A Granted JPS6134296A (en) | 1984-07-25 | 1984-07-25 | Treatment of unbleached pulp |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6134296A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4641629B2 (en) * | 2001-01-26 | 2011-03-02 | 日本製紙株式会社 | Cellulose fiber material pulp bleaching method |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0351388A (en) * | 1989-07-19 | 1991-03-05 | Mitsubishi Paper Mills Ltd | Method for washing digested pulp prior to oxygen bleaching |
| JP6494919B2 (en) * | 2014-03-27 | 2019-04-03 | 大阪瓦斯株式会社 | Nanocarbon dispersant |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5214326A (en) * | 1975-07-25 | 1977-02-03 | Hitachi Ltd | Data processor unit |
| JPS5218281A (en) * | 1975-08-03 | 1977-02-10 | Hitachi Koki Co Ltd | Cutter for vibration cutting tool |
| JPS5237082A (en) * | 1975-09-18 | 1977-03-22 | Nissan Motor Co Ltd | Tire air pressure alarming device for automobiles |
| JPS5237083A (en) * | 1975-09-18 | 1977-03-22 | Osaka Gas Co Ltd | A differential pressure measuring device for reaction pipes |
-
1984
- 1984-07-25 JP JP15447084A patent/JPS6134296A/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5214326A (en) * | 1975-07-25 | 1977-02-03 | Hitachi Ltd | Data processor unit |
| JPS5218281A (en) * | 1975-08-03 | 1977-02-10 | Hitachi Koki Co Ltd | Cutter for vibration cutting tool |
| JPS5237082A (en) * | 1975-09-18 | 1977-03-22 | Nissan Motor Co Ltd | Tire air pressure alarming device for automobiles |
| JPS5237083A (en) * | 1975-09-18 | 1977-03-22 | Osaka Gas Co Ltd | A differential pressure measuring device for reaction pipes |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4641629B2 (en) * | 2001-01-26 | 2011-03-02 | 日本製紙株式会社 | Cellulose fiber material pulp bleaching method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6134296A (en) | 1986-02-18 |
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