JP3945178B2 - Calcium-based scale inhibitor composition and water-based calcium scale preventive method - Google Patents
Calcium-based scale inhibitor composition and water-based calcium scale preventive method Download PDFInfo
- Publication number
- JP3945178B2 JP3945178B2 JP2001098697A JP2001098697A JP3945178B2 JP 3945178 B2 JP3945178 B2 JP 3945178B2 JP 2001098697 A JP2001098697 A JP 2001098697A JP 2001098697 A JP2001098697 A JP 2001098697A JP 3945178 B2 JP3945178 B2 JP 3945178B2
- Authority
- JP
- Japan
- Prior art keywords
- calcium
- scale
- water
- salt
- acid
- 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
Description
【０００１】
【発明の属する技術分野】
本発明は、相乗効果を奏する２種類のホスホン酸を必須成分として含有するカルシウム系スケールの防止剤組成物および上記組成物によるカルシウム系スケースの防止方法に関する。さらに詳しくは、カルシウム硬度３００ｍｇ／立以上、または／およびｐＨが９．６以上の水系においてもカルシウム系スケールの発生を防止するのに有用な組成物およびカルシウム系スケールの防止方法に関する。
【０００２】
【従来の技術】
各種工業水系において、水中の硬度成分と溶存炭酸塩によって生じる炭酸カルシウムを主とするカルシウム系スケールが発生し、様々な障害をもたらすことが広く知られており、この発生を防止またはできるだけ抑制することが望まれている。
このため従来から上記水系に添加してカルシウム系スケールの発生を防止または抑制する薬剤が種々提案されており、中でも有機ホスホン酸類が広く知られている（例えば特開昭６４−７７６９３号公報参照）。
しかしこれらホスホン酸類が効果を発揮し得る水質には上限があって、カルシウム硬度が非常に高い水系やｐＨが高い水系では薬剤の適用限界を越え、例え添加量を増やしても多大なスケール障害をもたらす場合が少なくない。特に湿式排煙脱硫工程水や製紙工業の脱墨工程水などでは水質変動が激しく、カルシウム硬度とｐＨが高いために安定したスケール防止効果を発揮する薬剤が望まれている。
水質変動の要因を例えば脱墨工程において挙げると、
▲１▼脱墨しようとする古紙原料から持ち込まれるカルシウム成分の量によって、水系のカルシウム硬度が変動する
▲２▼高濃度のパルプスラリーを希釈するために使用する水が循環使用されるため、循環回数の多寡によりカルシウム硬度およびｐＨが変動する
▲３▼漂白工程におけるアルカリ添加量により、脱墨工程のｐＨが変動する
ことが考えられる。
こうした変動要因をホスホン酸類の水質上限以下に制御することは該プロセスの性質から実質的に不可能であって、特にこうした水系では適用水質範囲の広いスケール防止方法が望まれている。
【０００３】
【発明が解決しようとする課題】
こうした課題を解決する目的で、例えば有機ホスホン酸類とアクリル酸系もしくはマレイン酸系共重合体、およびクエン酸からなるカルシウム系スケール防止剤（特開平５−４０９６号公報）が提案されているが、高い添加濃度が必要である上、カルシウム硬度が高く、且つｐＨが高い水系での効果が良くないという問題点がある。
【０００４】
本発明は上記の状況下になされたものであり、特に高硬度の水系や高ｐＨの水系においても優れたスケール防止効果を発現することができる適用範囲の広いカルシウム系スケールの防止剤組成物およびカルシウム系スケールの防止方法を提供するものである。
【０００５】
【課題を解決するための手段】
本発明の製紙工業の脱墨工程における水系添加用カルシウム系スケールの防止剤組成物は、１−ヒドロキシエチリデン−１，１−ジホスホン酸またはその塩と、２−ホスホノブタン−１，２，４−トリカルボン酸またはその塩との配合割合が１：９〜９：１であることを特徴とする。
また、本発明のカルシウム系スケールの防止方法は、カルシウム硬度が炭酸カルシウムとして３００ｍｇ／立以上、Ｍ−アルカリ度が３００ｍｇ／立以上、または／およびｐＨが９．６以上の製紙工業の脱墨工程における水系、あるいは水質変動により上記条件となる水系に対して、１−ヒドロキシエチリデン−１，１−ジホスホン酸またはその塩と、２−ホスホノブタン−１，２，４−トリカルボン酸またはその塩との配合割合が１：９〜９：１である組成物を添加することを特徴とする。
【０００６】
【発明の実施の形態】
本発明のカルシウム系スケールの防止剤組成物は、１−ヒドロキシエチリデン−１，１−ジホスホン酸（以下ＨＥＤＰとも記す。）またはその塩と、２−ホスホノブタン−１，２，４−トリカルボン酸（以下ＰＢＴＣとも記す。）またはその塩とを必須成分として配合して１剤としたものであり、ＨＥＤＰとＰＢＴＣの配合比は１：９〜９：１が好ましく、１：３〜３：１がさらに好ましい。尚、ホスホン酸塩としてはナトリウム塩、カリウム塩等のアルカリ金属塩、アンモニウム塩等である。
【０００７】
本発明の前記組成物は、ＨＥＤＰまたはその塩や、ＰＢＴＣまたはその塩の単独での使用に比べ相乗効果によって低添加量で効果を発揮する。さらに水質変動が大きい条件下であってもカルシウム系スケールの生成を抑制し得る。そして、本発明の相乗効果が奏される限り、ポリマー類、有機酸類、キレート剤類、本発明のＨＥＤＰ、ＰＢＴＣ以外の各種ホスホン酸類等の他の任意の成分を配合したり、併用しても差し支えない。このようにさらに配合する任意の成分としては例えば、ポリマーとしてアクリル酸と２−ヒドロキシー３−アリルオキシー１−プロパンスルホン酸との共重合体およびその塩、有機酸類としてクエン酸、リンゴ酸、グルコン酸およびそのアルカリ金属塩、キレート剤類としてエチレンジアミン四酢酸およびそのアルカリ金属塩、その他のホスホン酸類としてエチレンジアミンテトラメチレンホスホン酸およびその塩が挙げられる。
【０００８】
本発明の水系でのカルシウム系スケールの防止方法は、前記組成物をスケール障害が発生する工程の前段階に添加することが望ましい。本発明の前記組成物が効果を発揮する水中濃度は水質条件に依存するため、特に制限されないが、通常は水中濃度０．１ｍｇ／立から数十ｍｇ／立の少量で足りる。また添加方法としても特に制限はなく、添加は間欠的でもよいし、連続的でもよいが、スケールが発生する場所の前段階に添加することが望ましい。
【０００９】
〔本発明による組成物（実施例）と、本発明によらない組成物（比較例）との性能の比較試験〕
試験片を懸垂した炭酸カルシウムの過飽和水溶液に、上記実施例、比較例の各組成物を個々に添加し、その後の水質変化と、試験片へのスケール付着速度によって性能を比較した。用いた試験片は、３０×５０ｍｍ、厚さ１ｍｍのＳＵＳ３０４製であり、試験前にトルエンによる脱脂処理を行った。
具体的には、純水をベースとして塩化カルシウム水溶液を添加し、所定のカルシウム濃度に調製したあと、上記実施例、比較例の各組成物を添加し、続いて炭酸水素ナトリウム溶液を添加してアルカリ度を調製し、最後に水酸化ナトリウム溶液を添加してｐＨを調整した。この炭酸カルシウム過飽和水溶液を４０℃の恒温水槽に移し、マグネチックスターラーで１時間攪拌し、攪拌後、検液を０．２２μｍのフィルターで濾過し、濾液のカルシウム硬度をＪＩＳ０１０１の方法によって測定した。スケール付着速度は試験片を過飽和水溶液に一定時間浸漬し、浸漬後に取り出して１Ｎ塩酸水溶液に浸漬し、試験片に付着した炭酸カルシウムスケールを溶解し、溶解後のカルシウム硬度を上記と同様に測定し、この測定結果から換算してスケール付着量を求めた。スケールの付着速度はこのスケール付着量と試験片の表面積、試験期間から次式によって求めた。
スケール付着速度＝スケール付着量（ｇ）／試験期間（日）／試験片の表面積（ｍ2）
【００１０】
試験条件および試験結果をまとめて表−１に示す。
【００１１】
【表１】
〈相乗効果および高ｐＨにおける効果〉
ＨＥＤＰ単独処理では比較例１、２および比較例６、７に示すようにカルシウム硬度３００ｍｇ／立において、ｐＨが９．８を越えると添加濃度を高めても防止効果を得ることが困難である。
ＰＢＴＣ単独処理においても比較例３、４および比較例８〜１０に示すように、これも上記と同様である。これに対して、本発明の組成物は実施例１、２および８、９から明らかな通り、高ｐＨでも優れたスケール防止効果を示し、ｐＨ１０．６においてさえ低添加濃度で効果があり、単独添加の比較例と比較すると相乗効果が認められた。そこでＨＥＤＰとＰＢＴＣの配合割合を変えてその効果を比較したところ（実施例３〜７）、ｐＨ条件が極めて過酷な試験条件であったｐＨ１０．６においてさえ、１：９〜９：１という広い範囲で相乗効果が認められた。
【００１３】
〈高カルシウム硬度における効果〉
カルシウム硬度が高い条件におけるスケール防止効果を調べる目的から、カルシウム硬度９００ｍｇＣａＣＯ3／立、Ｍ−アルカリ度９００ｍｇＣａＣＯ3／立、ｐＨ９．６の条件で試験した結果、合計添加濃度が６ｍｇ／立という低濃度においてもほとんどスケール付着がない効果を示した（実施例１０）。
【００１４】
〈本発明によるカルシウム系スケールの防止方法の実施例〉
新聞古紙と雑誌古紙の混合物を原料とする某製紙工場の脱墨工程において、フローテーターの後工程にある過酸化水素漂白塔出口からシックナーに至る工程でスケール障害があった。すなわち過酸化水素漂白塔スラリーに対して２０ｍｇ／立となるようにスラリー希釈水にＨＥＤＰ塩を連続添加していたにも拘わらず、過酸化水素漂白塔以降の配管およびシックナーにスケールが発生し、パルプスラリーの流量が低下したり、シックナーが閉塞して処理不能になる障害があった。このため定期的に脱墨工程の運転を止めて酸洗浄をしていたが、度々不定期に洗浄をしなければならない状況であった。シックナーの絞り水の水質を測定したところ、次に示すように高ｐＨの系であった。
カルシム硬度 ：２９０ｍｇＣａＣＯ3／立
Ｍ−アルカリ度：６３０ｍｇＣａＣＯ3／立
ｐＨ ：１０．９
温度 ：３５℃
この系に対し、本発明のＨＥＤＰとＰＢＴＣの配合比率が１：１の実施例の組成物を合計有効成分として２０ｍｇ／立を同じ要領で連続添加した。この結果、シックナーにおける目詰まりは著しく減少し、定期洗浄までの期間中に突発的な洗浄をする必要がなくなった。また、定期的運転停止時に観察した配管内のスケール付着量も著しく低下していた。シックナーの絞り水が連続的に流れるシックナー下部の貯槽に、前述の比較試験で用いたのと同じ試験片を浸漬してスケール付着速度を測定したところ、ＨＥＤＰ単独処理時のスケール付着速度が７０ｇ／ｍ2／日であったのに対し、本発明によるＨＥＤＰ／ＰＢＴＣの併用処理では３ｇ／ｍ2／日であった。
この処理効果によって脱墨工程は洗浄のための不定期の運転停止がなく、安定な操業が可能になった。
【００１５】
【発明の効果】
請求項１により、高硬度のカルシウム硬度または／および高ｐＨの製紙工業の脱墨工程における水系に対して、少ない添加量でカルシウム系スケールの発生を防止する組成物を提供することができる。又、請求項２により、高硬度のカルシウム硬度または／および高ｐＨの製紙工業の脱墨工程における水系に少量、添加し、カルシウム系スケールの発生を大幅に抑制し、水系の運転を安定に行うことができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a calcium-based scale inhibitor composition containing two kinds of phosphonic acids having synergistic effects as essential components, and a method for preventing calcium-based case by the above composition. More specifically, the present invention relates to a composition useful for preventing the occurrence of calcium-based scale even in an aqueous system having a calcium hardness of 300 mg / rise or higher, or / and a pH of 9.6 or higher, and a method for preventing calcium-based scale.
[0002]
[Prior art]
In various industrial water systems, it is widely known that calcium-based scales mainly composed of calcium carbonate generated by hardness components in water and dissolved carbonates are generated, causing various obstacles. Prevent or suppress this generation as much as possible. Is desired.
For this reason, various agents have been proposed so far to prevent or suppress the generation of calcium-based scale by adding to the aqueous system, and among them, organic phosphonic acids are widely known (see, for example, JP-A-64-76993). .
However, there is an upper limit to the water quality that these phosphonic acids can exert their effects on. The water system with extremely high calcium hardness and water system with high pH exceeds the application limit of the drug. There are many cases to bring. In particular, wet flue gas desulfurization process water and deinking process water in the paper industry have drastic fluctuations in water quality, and since calcium hardness and pH are high, a chemical that exhibits a stable scale prevention effect is desired.
For example, in the deinking process, the causes of water quality fluctuations
(1) The calcium hardness of the water system varies depending on the amount of calcium component brought from the used paper raw material to be deinked. (2) Since the water used for diluting the high-concentration pulp slurry is recycled, it is circulated. Calcium hardness and pH fluctuate depending on the number of times. (3) It is conceivable that the pH of the deinking process varies depending on the amount of alkali added in the bleaching process.
Control of these fluctuation factors below the upper limit of water quality of phosphonic acids is substantially impossible due to the nature of the process, and in particular in such water systems, a scale prevention method with a wide range of applicable water quality is desired.
[0003]
[Problems to be solved by the invention]
In order to solve such problems, for example, a calcium-based scale inhibitor (Japanese Patent Laid-Open No. 5-4096) comprising an organic phosphonic acid and an acrylic acid- or maleic acid-based copolymer and citric acid has been proposed. In addition to the need for a high concentration of addition, there is a problem that the effect in an aqueous system having high calcium hardness and high pH is not good.
[0004]
The present invention has been made under the above-described circumstances, and has a wide application range of calcium-based scale inhibitor composition capable of exhibiting an excellent scale prevention effect even in a high-hardness aqueous system and a high-pH aqueous system. A method for preventing a calcium-based scale is provided.
[0005]
[Means for Solving the Problems]
The calcium-based scale inhibitor composition for aqueous addition in the deinking process of the paper industry of the present invention comprises 1-hydroxyethylidene-1,1-diphosphonic acid or a salt thereof and 2-phosphonobutane-1,2,4-tricarboxylic acid. The compounding ratio with an acid or a salt thereof is 1: 9 to 9: 1.
Further, the method for preventing calcium-based scale of the present invention is a deinking process in the paper industry where the calcium hardness is 300 mg / standing or more as calcium carbonate, the M-alkaliness is 300 mg / standing or more, and / or the pH is 9.6 or more. Of 1-hydroxyethylidene-1,1-diphosphonic acid or a salt thereof and 2-phosphonobutane-1,2,4-tricarboxylic acid or a salt thereof with respect to an aqueous system or an aqueous system that satisfies the above conditions due to water quality fluctuations A composition having a ratio of 1: 9 to 9: 1 is added.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The calcium-based scale inhibitor composition of the present invention comprises 1-hydroxyethylidene-1,1-diphosphonic acid (hereinafter also referred to as HEDP) or a salt thereof, and 2-phosphonobutane-1,2,4-tricarboxylic acid (hereinafter referred to as “HELP”). PBTC) or a salt thereof as an essential component to form one agent, and the blending ratio of HEDP and PBTC is preferably 1: 9 to 9: 1, and more preferably 1: 3 to 3: 1. preferable. Examples of the phosphonate include alkali metal salts such as sodium salt and potassium salt, ammonium salt and the like.
[0007]
The composition of the present invention exhibits an effect at a low addition amount due to a synergistic effect as compared with the use of HEDP or a salt thereof, or PBTC or a salt thereof alone. Furthermore, the formation of calcium-based scale can be suppressed even under conditions where the water quality fluctuation is large. And as long as the synergistic effect of the present invention is exhibited, other optional components such as polymers, organic acids, chelating agents, various phosphonic acids other than HEDP and PBTC of the present invention may be blended or used together. There is no problem. As optional components to be further blended in this way, for example, a copolymer of acrylic acid and 2-hydroxy-3-allyloxy-1-propanesulfonic acid and a salt thereof as a polymer, and citric acid, malic acid, and gluconic acid as organic acids And its alkali metal salts, ethylenediaminetetraacetic acid and its alkali metal salts as chelating agents, and ethylenediaminetetramethylenephosphonic acid and its salts as other phosphonic acids.
[0008]
In the method for preventing calcium-based scale in an aqueous system of the present invention, it is desirable to add the composition to a stage prior to the process of causing scale failure. The concentration in water at which the composition of the present invention exhibits an effect depends on the water quality conditions, and is not particularly limited. However, a water concentration of 0.1 mg / standing to several tens mg / standing is usually sufficient. The addition method is not particularly limited, and the addition may be intermittent or continuous, but it is desirable to add it before the place where the scale is generated.
[0009]
[Comparison test of performance of composition according to the present invention (Example) and composition not according to the present invention (Comparative Example)]
The compositions of the above Examples and Comparative Examples were individually added to a supersaturated aqueous solution of calcium carbonate in which a test piece was suspended, and the performance was compared based on the subsequent change in water quality and the rate of scale adhesion to the test piece. The test piece used was made of SUS304 having a size of 30 × 50 mm and a thickness of 1 mm, and degreased with toluene before the test.
Specifically, after adding a calcium chloride aqueous solution based on pure water and adjusting to a predetermined calcium concentration, each composition of the above Examples and Comparative Examples was added, and then a sodium bicarbonate solution was added. The alkalinity was adjusted, and finally the sodium hydroxide solution was added to adjust the pH. This calcium carbonate supersaturated aqueous solution was transferred to a constant temperature water bath at 40 ° C. and stirred for 1 hour with a magnetic stirrer. After stirring, the test solution was filtered with a 0.22 μm filter, and the calcium hardness of the filtrate was measured by the method of JIS0101. The scale adhesion rate was determined by immersing the test piece in a supersaturated aqueous solution for a certain period of time, taking it out and immersing it in a 1N hydrochloric acid aqueous solution, dissolving the calcium carbonate scale attached to the test piece, and measuring the calcium hardness after dissolution in the same manner as described above. From this measurement result, the scale adhesion amount was determined. The scale deposition rate was determined from the scale deposition amount, the surface area of the test piece, and the test period according to the following equation.
Scale adhesion rate = scale adhesion amount (g) / test period (days) / surface area of test piece (m 2 )
[0010]
The test conditions and test results are summarized in Table-1.
[0011]
[Table 1]
<Synergistic effect and effect at high pH>
In the HEDP single treatment, as shown in Comparative Examples 1, 2 and Comparative Examples 6 and 7, at a calcium hardness of 300 mg / stand, when the pH exceeds 9.8, it is difficult to obtain the prevention effect even if the addition concentration is increased.
In the PBTC single treatment, as shown in Comparative Examples 3 and 4 and Comparative Examples 8 to 10, this is also the same as described above. On the other hand, as is clear from Examples 1, 2, 8 and 9, the composition of the present invention exhibits an excellent scale prevention effect even at a high pH, and is effective even at a pH of 10.6 at a low addition concentration. A synergistic effect was observed when compared with the comparative example of addition. Thus, when the effects were compared by changing the blending ratio of HEDP and PBTC (Examples 3 to 7), even at pH 10.6 where the pH conditions were extremely severe test conditions, a wide range of 1: 9 to 9: 1 was obtained. A synergistic effect was observed in the range.
[0013]
<Effect on high calcium hardness>
For the purpose of investigating the scale prevention effect under the condition of high calcium hardness, as a result of testing under the conditions of calcium hardness 900 mg CaCO 3 / standing, M-alkalinity 900 mg CaCO 3 / standing, pH 9.6, the total added concentration is a low concentration of 6 mg / standing (Example 10) which showed the effect with almost no scale adhesion.
[0014]
<Examples of the method for preventing calcium-based scale according to the present invention>
In the deinking process of a paper mill using a mixture of used newspaper and magazine paper, there was a scale hindrance in the process from the hydrogen peroxide bleaching tower outlet to the thickener in the post-process of the flotator. That is, although the HEDP salt was continuously added to the slurry dilution water so as to be 20 mg / standing with respect to the hydrogen peroxide bleaching tower slurry, a scale was generated in the pipe and thickener after the hydrogen peroxide bleaching tower, There were obstacles in which the flow rate of the pulp slurry was reduced or the thickener was blocked and became unprocessable. For this reason, the operation of the deinking process was periodically stopped and the acid cleaning was performed. However, it was often necessary to perform the cleaning irregularly. As a result of measuring the water quality of the thickener's squeezed water, it was a high pH system as shown below.
Calcium hardness: 290 mg CaCO 3 / standing M-alkalinity: 630 mg CaCO 3 / standing pH: 10.9
Temperature: 35 ° C
To this system, 20 mg / stand was continuously added in the same manner as the total active ingredient of the composition of the example in which the blending ratio of HEDP and PBTC of the present invention was 1: 1. As a result, clogging in the thickener is remarkably reduced, and there is no need for sudden cleaning during the period until the regular cleaning. In addition, the amount of scale adhesion in the pipes observed at the time of periodic shutdown was significantly reduced. When the scale adhesion rate was measured by immersing the same specimen as used in the above-mentioned comparative test in a storage tank under the thickener where the squeezed water of the thickener continuously flows, the scale adhesion rate during the HEDP single treatment was 70 g / While it was m 2 / day, it was 3 g / m 2 / day in the combined treatment of HEDP / PBTC according to the present invention.
Due to this treatment effect, the deinking process can be operated stably without an irregular shutdown for cleaning.
[0015]
【The invention's effect】
According to the first aspect, it is possible to provide a composition that prevents the occurrence of calcium-based scale with a small addition amount with respect to the aqueous system in the deinking process of the paper industry with high hardness or / and high pH. Further, according to claim 2, a small amount is added to the aqueous system in the deinking process of high hardness calcium hardness and / or high pH paper industry, and the generation of calcium scale is greatly suppressed, and the aqueous system is stably operated. be able to.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001098697A JP3945178B2 (en) | 2001-03-30 | 2001-03-30 | Calcium-based scale inhibitor composition and water-based calcium scale preventive method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001098697A JP3945178B2 (en) | 2001-03-30 | 2001-03-30 | Calcium-based scale inhibitor composition and water-based calcium scale preventive method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002292398A JP2002292398A (en) | 2002-10-08 |
| JP3945178B2 true JP3945178B2 (en) | 2007-07-18 |
Family
ID=18952327
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001098697A Expired - Lifetime JP3945178B2 (en) | 2001-03-30 | 2001-03-30 | Calcium-based scale inhibitor composition and water-based calcium scale preventive method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3945178B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4520424B2 (en) * | 2006-04-10 | 2010-08-04 | 伯東株式会社 | Cleaning method for paper and pulp manufacturing process |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2325829C2 (en) * | 1973-05-22 | 1982-04-01 | Henkel KGaA, 4000 Düsseldorf | Sequestrants |
| JPS58199877A (en) * | 1982-05-03 | 1983-11-21 | ナルコ・ケミカル・カンパニ− | Composition and method of preventing corrosion of ferrous metal |
| JPS63258697A (en) * | 1987-04-16 | 1988-10-26 | Hakutou Kagaku Kk | Corrosion inhibitor also for suppressing scale of metals in aqueous system |
| JP3928182B2 (en) * | 1995-09-29 | 2007-06-13 | 栗田工業株式会社 | Corrosion prevention and scale prevention method for open circulation cooling water system |
| JP4043551B2 (en) * | 1997-05-23 | 2008-02-06 | 栗田工業株式会社 | Scale inhibitor and scale prevention method |
-
2001
- 2001-03-30 JP JP2001098697A patent/JP3945178B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JP2002292398A (en) | 2002-10-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7252769B2 (en) | Use of cerium salts to inhibit manganese deposition in water systems | |
| JP4298927B2 (en) | Scaling and corrosion inhibiting composition | |
| CA1039613A (en) | Method and composition of inhibiting scale | |
| JPH0848875A (en) | Composition for water treatment | |
| US7285221B2 (en) | Composition for preventing of slime and method for preventing slime | |
| JPH07155558A (en) | Method of preventing formation of scale and/or dispersing iron in reverse osmosis device | |
| FR2556335A1 (en) | COMPOSITION AND METHOD FOR INHIBITING TARTAR FORMATION | |
| JP3945178B2 (en) | Calcium-based scale inhibitor composition and water-based calcium scale preventive method | |
| JP5717760B2 (en) | Method for scale removal and reduction | |
| FR2533549A1 (en) | COMPOSITION AND METHOD FOR INHIBITING TARTAR FORMATION | |
| US4216087A (en) | Scrubber scale prevention | |
| TW202132228A (en) | Agent for preventing calcium-based scale in water systems, and scale prevention method | |
| JP4520424B2 (en) | Cleaning method for paper and pulp manufacturing process | |
| JP2006225742A (en) | Boiler water system treatment agent and method for treating boiler water system using the same | |
| JP2004293028A (en) | Scale inhibitor and scale inhibitory method for barium sulfate in water system | |
| JP2000117292A (en) | Calcium oxalate scale inhibitor for use in paper pulp production process | |
| JP3273956B2 (en) | Calcium sulfate scale inhibitor and method of prevention | |
| JP6835106B2 (en) | Water treatment agent | |
| JPH0892888A (en) | Scale preventing agent and prevention of scale in deinking process of wastepaper | |
| JP5396811B2 (en) | Boiler water treatment agent and water treatment method | |
| JP2011206723A (en) | Scale inhibition method | |
| JP4373591B2 (en) | Scaling suppression method in waste paper deinked pulp manufacturing process | |
| JP5119214B2 (en) | Slime control method in water system | |
| TW202313189A (en) | Cleaning agent, cleaning liquid and cleaning method for aromatic polyamide reverse osmosis membranes | |
| JP4176179B2 (en) | Scale control method in pulp bleaching process |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20070116 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20070223 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20070320 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20070402 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 Ref document number: 3945178 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100420 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110420 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120420 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120420 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130420 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140420 Year of fee payment: 7 |
|
| EXPY | Cancellation because of completion of term |