JPH0666783A - Method and instrument for measuring concentration of nitric acid and hydrofluoric acid in stainless steel pickling liquid - Google Patents
Method and instrument for measuring concentration of nitric acid and hydrofluoric acid in stainless steel pickling liquidInfo
- Publication number
- JPH0666783A JPH0666783A JP22437592A JP22437592A JPH0666783A JP H0666783 A JPH0666783 A JP H0666783A JP 22437592 A JP22437592 A JP 22437592A JP 22437592 A JP22437592 A JP 22437592A JP H0666783 A JPH0666783 A JP H0666783A
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- Prior art keywords
- concentration
- acid
- nitric acid
- titration
- hydrofluoric acid
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、主としてステンレス鋼
洗浄後の酸混合液中に残存する硝酸と弗酸の濃度を分別
測定する方法およびその装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a method and apparatus for separately measuring the concentrations of nitric acid and hydrofluoric acid remaining in an acid mixture after cleaning stainless steel.
【０００２】[0002]
【従来の技術と考案が解決しようとする課題】ステンレ
ス鋼の酸洗浄液は、主として硝酸と弗酸の混合水溶液を
用いている。洗浄効果に顕著に寄与する成分は、他のイ
オン等と結合していない硝酸と弗酸であり、洗浄に適す
る濃度はステンレス鋼の種類により異なっている。従っ
て、洗浄効果を高めるためには、その濃度管理を常に適
性に行なう必要がある。2. Description of the Related Art As an acid cleaning solution for stainless steel, a mixed aqueous solution of nitric acid and hydrofluoric acid is mainly used. The components that significantly contribute to the cleaning effect are nitric acid and hydrofluoric acid that are not combined with other ions, and the concentration suitable for cleaning differs depending on the type of stainless steel. Therefore, in order to enhance the cleaning effect, it is necessary to always properly control the concentration.
【０００３】しかし硝酸と弗酸は解離定数の差が小さ
く、また洗浄液中には洗浄により溶解した鉄イオン、ク
ロムイオン、ニッケルイオンが共存するため、このよう
な系の中の硝酸、弗酸を選択的に分別定量するのは困難
である。However, nitric acid and hydrofluoric acid have a small difference in dissociation constants, and iron ions, chromium ions, and nickel ions dissolved by cleaning coexist in the cleaning liquid. It is difficult to selectively separate and quantify.
【０００４】とりわけｐＨ２程度からアルカリと反応す
る第二鉄イオン（Ｆｅ３＋）が共存するため、簡単に中
和滴定法を適用できない。そのため従来より、検出器と
してＦ−イオン電極とＮＯ３−イオン電極を用いたイオ
ンメーター方式が採用されている。Especially, since the ferric ion (Fe 3+ ) which reacts with alkali from the pH of about 2 coexists, the neutralization titration method cannot be easily applied. Therefore, conventionally, an ion meter system using an F − ion electrode and a NO 3 − ion electrode as a detector has been adopted.
【０００５】しかし一般的にイオン電極は不安定である
ため、測定の度に標準液で検量線を求める必要がある。
また、これらの装置は機構が複雑であり、実際の現場で
は安定に稼働していないのが実情である。However, since the ion electrode is generally unstable, it is necessary to obtain a calibration curve using a standard solution each time measurement is performed.
Moreover, the mechanism of these devices is complicated, and the actual situation is that they are not operating stably in the actual field.
【０００６】また、この方式では、酸洗浄液中に共存す
る硝酸鉄、弗化鉄等から解離するＮＯ３−イオン、Ｆ−
イオンも合わせたトータルのイオン濃度を測定してお
り、正確な硝酸、弗酸の濃度を知ることはできなかっ
た。Further, in this system, NO 3 − ions and F − which are dissociated from iron nitrate, iron fluoride and the like coexisting in the acid cleaning solution.
Since the total ion concentration including the ions was measured, it was not possible to know the exact concentrations of nitric acid and hydrofluoric acid.
【０００７】本発明は上記に鑑みてなしたもので、硝
酸、弗酸の濃度が選択的に測定できる濃度測定方法を提
供するものであり、また、機構が簡単なため使い易く、
しかも信頼性の高いデータが得られる濃度自動測定装置
を提供するものである。The present invention has been made in view of the above, and provides a concentration measuring method capable of selectively measuring the concentrations of nitric acid and hydrofluoric acid. Moreover, since the mechanism is simple, it is easy to use,
Moreover, the present invention provides an automatic concentration measuring device that can obtain highly reliable data.
【０００８】[0008]
【課題を解決するための手段】本発明のステンレス鋼酸
洗浄液中の硝酸、弗酸濃度測定方法は、上記の課題を解
決するために、ステンレス鋼洗浄後の酸混合液であるサ
ンプルに還元試薬を加えた上で濃度既知の中和滴定試薬
により滴定して全酸濃度を求め、前記サンプルを非水溶
媒系で濃度既知の置換滴定試薬により滴定して硝酸濃度
を求め、前記全酸濃度と前記硝酸濃度より弗酸濃度を求
めることを特徴とする。In order to solve the above-mentioned problems, a method for measuring the concentration of nitric acid and hydrofluoric acid in a stainless steel acid cleaning solution of the present invention is to reduce a sample which is an acid mixed solution after cleaning stainless steel to a reducing reagent. To determine the total acid concentration by titration with a known concentration neutralization titration reagent, to determine the nitric acid concentration by titrating the sample with a displacement titration reagent of known concentration in a non-aqueous solvent system, and the total acid concentration It is characterized in that the hydrofluoric acid concentration is obtained from the nitric acid concentration.
【０００９】また本発明の自動濃度測定装置は、撹拌装
置と排出管とを備えた反応容器と、該反応容器にサンプ
ルを供給する導入管と、該反応容器に還元試薬、中和滴
定試薬および置換滴定試薬を別々に供給するための３つ
のタンクと、該反応容器内の液の水素イオン指数を検出
するｐＨ検出器とを有することを特徴とする。Further, the automatic concentration measuring apparatus of the present invention comprises a reaction vessel equipped with a stirrer and a discharge tube, an introducing tube for supplying a sample to the reaction vessel, a reducing reagent, a neutralization titration reagent and It is characterized by having three tanks for separately supplying displacement titration reagents and a pH detector for detecting the hydrogen ion exponent of the liquid in the reaction vessel.
【００１０】[0010]
【作用】上記の構成よりなる本発明のステンレス鋼酸洗
浄液中の硝酸、弗酸濃度測定方法は、中和滴定法と置換
滴定法とを採用することにより、硝酸と弗酸の濃度の選
択的な測定を可能にした。すなわち濃度は以下の手順に
従って決定される。The method of measuring the concentration of nitric acid and hydrofluoric acid in the stainless steel acid cleaning solution of the present invention having the above-mentioned constitution employs the neutralization titration method and the displacement titration method to selectively select the nitric acid and hydrofluoric acid concentrations. It enabled various measurements. That is, the concentration is determined according to the following procedure.
【００１１】１．全酸（硝酸＋弗酸）濃度の測定 サンプルを一定量正確に採取して水を加え、還元試薬を
加えてＦｅ３＋イオンを還元したのち、濃度既知のＮａ
ＯＨ標準溶液等の中和滴定試薬により、ｐＨ検出器を用
いて滴定する。 1. A sample of the total acid (nitric acid + hydrofluoric acid) concentration was accurately sampled, water was added, and a reducing reagent was added to reduce Fe 3+ ions.
Titrate using a pH detector with a neutralizing titration reagent such as an OH standard solution.
【００１２】 Ｆｅ３＋ ＋ ｅ− → Ｆｅ２＋ （還元反応） ＨＮＯ３ ＋ＮａＯＨ→ ＮａＮＯ３ ＋Ｈ２Ｏ （中和反応） ＨＦ ＋ＮａＯＨ→ ＮａＦ ＋Ｈ２Ｏ （中和反応）Fe 3+ + e − → Fe 2+ (reduction reaction) HNO 3 + NaOH → NaNO 3 + H 2 O (neutralization reaction) HF + NaOH → NaF + H 2 O (neutralization reaction)
【００１３】２．硝酸濃度の測定 サンプルを一定量正確に採取し、エタノール等の非水溶
媒を加え、還元試薬を加えてＦｅ３＋イオンを還元した
のち、濃度既知のＣＨ３ＣＯＯＮａ標準溶液等の置換滴
定試薬を用いて滴定する。 2. A certain amount of nitric acid concentration measurement sample was accurately sampled, a non-aqueous solvent such as ethanol was added, a reducing reagent was added to reduce Fe 3+ ions, and then a displacement titration reagent such as a known CH 3 COONa standard solution was used. And titrate.
【００１４】硝酸、弗酸、酢酸の水系における解離定数
ｐＫａは次の通りである。The dissociation constant pKa of nitric acid, hydrofluoric acid and acetic acid in an aqueous system is as follows.
【００１５】 ＨＮＯ３ ： ほぼ完全解離 ＨＦ ： ３．１７ ＣＨ３ＣＯＯＮａ： ４．５６ エタノールやメタノール等の非水溶媒系においてはこの
ｐＫａ差は拡大する方向にあり、この系で滴定すると弗
酸は滴定されず、硝酸のみが滴定される。HNO 3 : Almost complete dissociation HF: 3.17 CH 3 COONa: 4.56 In a non-aqueous solvent system such as ethanol or methanol, this pKa difference tends to widen, and when titrated in this system, hydrofluoric acid is released. Not titrated, only nitric acid.
【００１６】 Ｆｅ３＋ ＋ ｅ− → Ｆｅ２＋ （還元反応） ＨＮＯ３ ＋ＣＨ３ＣＯＯＮａ→ ＣＨ３ＣＯＯＨ ＋ＮａＮＯ３ （置換反応）Fe 3+ + e − → Fe 2+ (reduction reaction) HNO 3 + CH 3 COONa → CH 3 COOH + NaNO 3 (replacement reaction)
【００１７】３．硝酸および弗酸の濃度の算出 上記１、２により得られた滴定試薬の消費量を用いて、
次式に従い、硝酸および弗酸の濃度を算出する。 3. Calculation of the concentration of nitric acid and hydrofluoric acid Using the consumption of the titration reagent obtained in the above 1 and 2,
The concentrations of nitric acid and hydrofluoric acid are calculated according to the following formula.
【００１８】 ＨＮＯ３（Ｎ）＝Ｂ×Ｎ２×ｆ２÷Ｓ ＨＦ （Ｎ）＝｛（ＡＮ１ｆ１）−（ＢＮ２ｆ２）｝
÷Ｓ ただし Ａ ：ＮａＯＨ標準溶液の消費量（ｍｌ） Ｂ ：ＣＨ３ＣＯＯＮａ標準溶液の消費量（ｍｌ） Ｎ１：ＮａＯＨ標準溶液の規定度（Ｎ） Ｎ２：ＣＨ３ＣＯＯＮａ標準溶液の規定度（Ｎ） ｆ１：ＮａＯＨ標準溶液の力価 ｆ２：ＣＨ３ＣＯＯＮａ標準溶液の力価 Ｓ ：サンプル採取量（ｍｌ）HNO 3 (N) = B × N 2 × f 2 ÷ S HF (N) = {(AN 1 f 1 ) − (BN 2 f 2 )}
÷ S where A: consumption of NaOH standard solution (ml) B: consumption of CH 3 COONa standard solution (ml) N 1 : normality of NaOH standard solution (N) N 2 : normality of CH 3 COONa standard solution (N) f 1 : titer of NaOH standard solution f 2 : titer of CH 3 COONa standard solution S: sampled amount (ml)
【００１９】[0019]
【実施例】次に本発明を図に基づいて詳細に説明する。The present invention will now be described in detail with reference to the drawings.
【００２０】図１は、本発明に係わる自動濃度測定装置
Ａを示す模式図である。FIG. 1 is a schematic view showing an automatic concentration measuring device A according to the present invention.
【００２１】濃度測定のための滴定反応は、自動濃度測
定装置Ａにおける反応容器１内で行なわれる。前記反応
容器１は底部からバルブ１１ａを備えた排出管１１が延
びているとともに、撹拌装置２が備えられている。反応
容器１には導入管４ａの一端が挿入され、導入管４ａの
他端は中和滴定試薬タンク４に接続されている。また反
応容器１には導入管５ａの一端が挿入され、導入管５ａ
の他端は置換滴定試薬タンク５に接続されている。さら
に反応容器１には導入管６ａの一端が挿入され、導入管
６ａの他端は還元試薬タンク６に接続されている。The titration reaction for measuring the concentration is carried out in the reaction container 1 of the automatic concentration measuring device A. The reaction vessel 1 is provided with a stirrer 2 as well as a discharge pipe 11 having a valve 11a extending from the bottom. One end of the introduction pipe 4a is inserted into the reaction container 1, and the other end of the introduction pipe 4a is connected to the neutralization titration reagent tank 4. Further, one end of the introduction pipe 5a is inserted into the reaction vessel 1 and the introduction pipe 5a
The other end of is connected to the displacement titration reagent tank 5. Further, one end of an introducing pipe 6a is inserted into the reaction container 1, and the other end of the introducing pipe 6a is connected to the reducing reagent tank 6.
【００２２】また反応容器１には計量管１０が挿入さ
れ、計量管１０はサンプル導入管７、非水溶媒導入管
８、水導入管９とそれぞれバルブ７ａ、８ａ、９ａを介
して接続している。A measuring pipe 10 is inserted into the reaction vessel 1, and the measuring pipe 10 is connected to the sample introducing pipe 7, the non-aqueous solvent introducing pipe 8 and the water introducing pipe 9 via valves 7a, 8a and 9a, respectively. There is.
【００２３】さらに反応容器１には、容器内の液の水素
イオン指数（ｐＨ）を検出するｐＨ検出器３が挿入され
ている。Furthermore, a pH detector 3 for detecting the hydrogen ion index (pH) of the liquid in the container is inserted in the reaction container 1.
【００２４】上記構成の自動濃度測定装置Ａにおいて、
サンプル導入管７から送られてきたサンプルは、計量管
１０により一定量計りとられて反応容器１に投入され
る。さらに投入されたサンプルにおける全酸濃度を測定
する際には、バルブ９ａを開栓して水を反応容器１に導
入し、硝酸濃度を測定する際には、バルブ８ａを開栓し
てエタノール等の非水溶媒を反応容器１に導入する。こ
のとき計量管１０の管内部に残存するサンプルも反応容
器１に洗い出されることになる。In the automatic concentration measuring device A having the above structure,
The sample sent from the sample introducing pipe 7 is weighed in a fixed amount by the measuring pipe 10 and put into the reaction container 1. Further, when measuring the total acid concentration in the added sample, the valve 9a is opened to introduce water into the reaction vessel 1. When measuring the nitric acid concentration, the valve 8a is opened to remove ethanol or the like. The non-aqueous solvent of 1 is introduced into the reaction vessel 1. At this time, the sample remaining inside the measuring tube 10 is also washed out into the reaction container 1.
【００２５】水あるいは非水溶媒が添加された前記サン
プルを撹拌しながら、還元試薬タンク６から還元試薬を
導入したのち、全酸濃度の測定の際には中和滴定試薬タ
ンク４から、硝酸濃度の測定の際には置換滴定試薬タン
ク５からそれぞれ滴定試薬を導入して滴定を行なう。After the reducing reagent was introduced from the reducing reagent tank 6 while stirring the sample to which water or a non-aqueous solvent had been added, the nitric acid concentration was measured from the neutralizing titration reagent tank 4 when measuring the total acid concentration. At the time of measurement, the titration reagent is introduced from the substitution titration reagent tank 5 to perform the titration.
【００２６】本発明の自動濃度測定装置Ａを用いてステ
ンレス鋼洗浄液であるサンプル中に残存する硝酸と弗酸
の濃度を下記（１）〜（３）に従って測定した。Using the automatic concentration measuring device A of the present invention, the concentrations of nitric acid and hydrofluoric acid remaining in the sample as the stainless steel cleaning liquid were measured according to the following (1) to (3).
【００２７】（１）全酸（硝酸＋弗酸）濃度の測定 サンプル０．５ｍｌを正確に採取して水を加えて約４０
ｍｌとし、次に０．１Ｎ−Ｎａ２Ｓ２Ｏ３１０ｍｌを加
えたのち、０．２Ｎ−ＮａＯＨ標準溶液等により、ｐＨ
検出器を用いて滴定を行なった。ＮａＯＨ標準溶液の消
費量は９．９５ｍｌであった。(1) Measurement of total acid (nitric acid + hydrofluoric acid) concentration 0.5 ml of a sample was accurately sampled and water was added to about 40 ml.
and ml, and then after the addition of 0.1N-Na 2 S 2 O 3 10ml, by 0.2 N-NaOH standard solution or the like, pH
Titration was performed using a detector. The consumption of NaOH standard solution was 9.95 ml.
【００２８】（２）硝酸濃度の測定 サンプル０．５ｍｌを正確に採取してエタノールを加え
て約４０ｍｌとし、０．１Ｎ−Ｎａ２Ｓ２Ｏ３１０ｍｌ
を加えたのち、０．２Ｎ−ＣＨ３ＣＯＯＮａ標準溶液に
よりｐＨ検出器を用いて滴定を行なった。ＣＨ３ＣＯＯ
Ｎａ標準溶液の消費量は５．０１ｍｌであった。(2) Measurement of nitric acid concentration Accurately collect 0.5 ml of a sample, add ethanol to about 40 ml, and add 0.1 N-Na 2 S 2 O 3 10 ml.
After the addition of, titration was conducted using a pH sensor by 0.2 N-CH 3 COONa standard solution. CH 3 COO
The consumption amount of Na standard solution was 5.01 ml.
【００２９】（３）硝酸および弗酸の濃度の算出 上記（１）、（２）により得られた滴定試薬の消費量を
用いて、硝酸および弗酸の濃度を計算し、以下の結果を
得た。(3) Calculation of nitric acid and hydrofluoric acid concentrations The nitric acid and hydrofluoric acid concentrations were calculated using the titration reagent consumptions obtained in (1) and (2) above, and the following results were obtained. It was
【００３０】 硝酸 ：２．００Ｎ 弗酸 ：１．９８Ｎ 上記結果が正確なものであることは、下記１〜６で行な
った試験により裏付けられる。Nitric acid: 2.00 N Hydrofluoric acid: 1.98 N The accuracy of the above results is confirmed by the tests conducted in the following 1 to 6.
【００３１】１．硝酸、弗酸および両者を混合した液の
水溶媒およびエタノール溶媒における０．２Ｎ−酢酸ナ
トリウム標準液による滴定 硝酸１．７６Ｎ溶液、弗酸１．５０Ｎ溶液を個々に０．
５ｍｌ正確に採取したもの、および各０．５ｍｌを正確
に採取して混合したものに水またはエタノールを加えて
約４０ｍｌとしたのち、ｐＨ検出器を用いて０．２Ｎ−
ＣＨ３ＣＯＯＮａ標準液による滴定を行なった。０．２
Ｎ−ＣＨ３ＣＯＯＮａ標準液の消費量を表１に示す。 1. Of nitric acid, hydrofluoric acid and a mixture of both
0.2N-acetic acid in water and ethanol
Thorium standard solution titrated nitric acid 1.76N solution, hydrofluoric acid 1.50N solution individually.
Water or ethanol was added to 5 ml accurately collected and 0.5 ml each accurately mixed and made up to about 40 ml, and then 0.2 N-using a pH detector.
Titration with CH 3 COONa standard solution was performed. 0.2
The consumption of N-CH 3 COONa standard solution shown in Table 1.
【００３２】[0032]
【表１】 [Table 1]
【００３３】水溶媒中では、硝酸、弗酸共に当量点が検
出され、両者を相当量含む混合液の測定値は測定誤差範
囲内で各々の測定値の和に等しい。ところがエタノール
溶媒中では、弗酸は酢酸ナトリウムとは反応せず、硝酸
と弗酸を混合した系においても硝酸のみの系とほぼ等し
い結果が得られた。すなわち、表１に示した結果は、こ
の手法により硝酸と弗酸の混合液中の硝酸を分別定量で
きることを示している。Equivalent points of both nitric acid and hydrofluoric acid are detected in the water solvent, and the measured value of the mixed solution containing both of them is equal to the sum of the measured values within the measurement error range. However, in an ethanol solvent, hydrofluoric acid did not react with sodium acetate, and even in a system in which nitric acid and hydrofluoric acid were mixed, almost the same results were obtained as in a system containing only nitric acid. That is, the results shown in Table 1 show that the nitric acid in the mixed liquid of nitric acid and hydrofluoric acid can be fractionally determined by this method.
【００３４】２．硝酸濃度測定の定量性および再現性の
確認 弗酸濃度を一定に保ち、硝酸濃度を変化させた調整サン
プルについて、エタノール溶媒中で前記と同様にして硝
酸濃度を測定し、測定値が理論濃度と一致するか調べ
た。結果を表２に示す。 2. Of quantitative and reproducible nitric acid concentration measurement
The nitric acid concentration was measured in an ethanol solvent in the same manner as described above for the adjusted samples in which the confirmed hydrofluoric acid concentration was kept constant and the nitric acid concentration was changed, and it was examined whether the measured value matches the theoretical concentration. The results are shown in Table 2.
【００３５】さらに表２のＮｏ．４の試料について濃度
測定を繰り返し５回おこない、測定結果の再現性を調べ
た。この結果を表３に示す。Further, in Table 2, No. The concentration measurement was repeated 5 times for the sample No. 4 and the reproducibility of the measurement results was examined. The results are shown in Table 3.
【００３６】[0036]
【表２】 [Table 2]
【００３７】[0037]
【表３】 [Table 3]
【００３８】表２に示した結果からわかるように、硝酸
の理論添加量と測定値は測定誤差の範囲内で良く一致し
ており、弗酸は検出されていないと考えることができ
る。As can be seen from the results shown in Table 2, the theoretical addition amount of nitric acid and the measured value are in good agreement within the range of measurement error, and it can be considered that hydrofluoric acid is not detected.
【００３９】また、表３に示したように繰り返し測定し
た場合の測定結果も安定しており、信頼度の高い測定が
可能であることがわかる。Further, as shown in Table 3, the measurement results of repeated measurement are stable, and it can be seen that highly reliable measurement is possible.
【００４０】３．弗酸が硝酸濃度測定に及ぼす影響の確
認 硝酸濃度を一定に保ち、弗酸濃度を変化させた調整サン
プルについて、エタノール溶媒中で前記と同様にして硝
酸濃度を測定し、弗酸濃度の影響を調べた。結果を表４
に示す。 3. To determine the effect of hydrofluoric acid on nitric acid concentration measurement
Maintaining the certification nitrate concentration constant, the adjustment sample with varying hydrofluoric acid concentration, the ethanol solvent and in the same manner by measuring the nitrate concentration, and the effect of hydrofluoric acid concentration. The results are shown in Table 4.
Shown in.
【００４１】[0041]
【表４】 [Table 4]
【００４２】表４に示した結果から、弗酸濃度が変化し
ても硝酸濃度の測定値には影響しないことがわかる。From the results shown in Table 4, it can be seen that changes in the concentration of hydrofluoric acid do not affect the measured value of nitric acid concentration.
【００４３】４．ステンレス鋼酸洗浄工程実液を用いた
弗酸濃度測定の定量性確認 ステンレス鋼酸洗浄工程後の実液に、それぞれ所定量の
弗酸を添加した調整サンプル０．５ｍｌを正確に採取し
て水を加えて約４０ｍｌとし、還元試薬として０．１Ｎ
−Ｎａ２Ｓ２Ｏ３１０ｍｌを加えてＦｅ３＋イオンを還
元したのち、０．２Ｎ−ＮａＯＨ標準液を用いて全酸濃
度を測定した。結果を表５に示す。 4. Stainless steel acid cleaning process using actual liquid
Quantitative confirmation of hydrofluoric acid concentration measurement To the actual liquid after the stainless steel acid washing step, 0.5 ml of the adjusted sample containing a predetermined amount of hydrofluoric acid was accurately sampled, and water was added to make about 40 ml. 0.1N
After reducing the Fe 3+ ions added -Na 2 S 2 O 3 10ml, was measured total acid concentration using a 0.2 N-NaOH standard solution. The results are shown in Table 5.
【００４４】[0044]
【表５】 [Table 5]
【００４５】表５に示したように、全酸測定値から算出
した弗酸添加量は、弗酸の理論添加量に良く一致してい
る。言い換えれば、全酸濃度の測定値は全酸濃度の理論
値と良く一致している。As shown in Table 5, the added amount of hydrofluoric acid calculated from the measured values of all acids is in good agreement with the theoretical added amount of hydrofluoric acid. In other words, the measured total acid concentration agrees well with the theoretical total acid concentration.
【００４６】５．ステンレス鋼酸洗浄工程実液を用いた
硝酸濃度測定の定量性確認 ステンレス鋼酸洗浄工程後の実液に、それぞれ所定量の
硝酸を添加した調整サンプル０．５ｍｌを正確に採取し
水を加えて約４０ｍｌとし、還元試薬として０．１Ｎ−
Ｎａ２Ｓ２Ｏ３１０ｍｌを加えたのち、０．２Ｎ−Ｎａ
ＯＨ標準液を用いて全酸濃度を測定した。結果を表６に
示す。 5. Stainless steel acid cleaning process using actual liquid
Quantitative confirmation of nitric acid concentration measurement Accurately collect 0.5 ml of the adjusted sample in which each predetermined amount of nitric acid was added to the actual liquid after the stainless steel acid washing step, add water to make about 40 ml, and use 0.1N as a reducing reagent. −
After addition of Na 2 S 2 O 3 10ml, 0.2N-Na
Total acid concentration was measured using OH standard solution. The results are shown in Table 6.
【００４７】[0047]
【表６】 [Table 6]
【００４８】表６に示したように、全酸測定値から算出
した硝酸添加量は、硝酸の理論添加量に良く一致してい
る。すなわち、全酸濃度の測定値は全酸濃度の理論値と
良く一致している。As shown in Table 6, the added amount of nitric acid calculated from the measured values of all acids is in good agreement with the theoretical added amount of nitric acid. That is, the measured value of the total acid concentration is in good agreement with the theoretical value of the total acid concentration.
【００４９】６．ステンレス鋼酸洗浄工程実液を用いた
硝酸濃度測定に弗酸が及ぼす影響の試験 ステンレス鋼酸洗浄工程後の実液に、それぞれ所定量の
弗酸を添加した調整サンプル０．５ｍｌを正確に採取
し、エタノールを加えて約４０ｍｌとし、０．１Ｎ−Ｎ
ａ２Ｓ２Ｏ３１０ｍｌを加えたのち、０．２Ｎ−ＣＨ３
ＣＯＯＮａ標準液を用いて硝酸濃度を測定した。結果を
表７に示す。 6. Stainless steel acid cleaning process using actual liquid
Test of the effect of hydrofluoric acid on nitric acid concentration measurement Accurately collect 0.5 ml of the adjusted sample in which a predetermined amount of hydrofluoric acid was added to the actual liquid after the stainless steel acid washing step, and add ethanol to make about 40 ml, 0.1N-N
After addition of a 2 S 2 O 3 10ml, 0.2N-CH 3
The nitric acid concentration was measured using COONa standard solution. The results are shown in Table 7.
【００５０】[0050]
【表７】 [Table 7]
【００５１】表７に示したように、弗酸を添加しても硝
酸の測定値は変化しなかった。すなわち、ステンレス鋼
酸洗浄工程後の実液の硝酸濃度測定において、弗酸濃度
は影響を与えないことが確認された。As shown in Table 7, addition of hydrofluoric acid did not change the measured value of nitric acid. That is, it was confirmed that the concentration of hydrofluoric acid did not affect the measurement of nitric acid concentration of the actual liquid after the stainless steel acid washing step.
【００５２】[0052]
【発明の効果】上記したように、本発明の濃度測定方法
によれば、ステンレス鋼酸洗浄液中の硝酸、弗酸の濃度
を選択的に測定することができ、また検出にはｐＨ検出
器を用いるため安定したデータが得られる。さらに本発
明の濃度測定装置は機構が簡単であるので操作やメンテ
ナンスが容易である。As described above, according to the concentration measuring method of the present invention, the concentrations of nitric acid and hydrofluoric acid in the stainless steel acid cleaning solution can be selectively measured, and a pH detector is used for detection. Since it is used, stable data can be obtained. Furthermore, the concentration measuring device of the present invention has a simple mechanism, and thus is easy to operate and maintain.
【００５３】[0053]
【００５４】[0054]
【図１】図１は、本発明に係る濃度自動測定装置を示す
模式図である。FIG. 1 is a schematic diagram showing an automatic concentration measuring apparatus according to the present invention.
【００５５】[0055]
Ａ ……濃度自動測定装置 １ ……反応容器 ２ ……撹拌装置 ３ ……ｐＨ検出器 ４ ……中和滴定試薬タンク ４ａ……導入管 ５ ……置換滴定試薬タンク ５ａ……導入管 ６ ……還元試薬タンク ６ａ……導入管 ７ ……サンプル導入管 ８ ……非水溶媒導入管 ９ ……水導入管 ７ａ，８ａ，９ａ……バルブ １０……計量管 １１……排出管 １１ａ……バルブ A: Automatic concentration measuring device 1 ... Reaction vessel 2 ... Stirring device 3 ... pH detector 4 ... Neutralization titration reagent tank 4a ... Introducing tube 5 ... Displacement titration reagent tank 5a ... Introducing tube 6 ... … Reducing reagent tank 6a …… Introduction pipe 7 …… Sample introduction pipe 8 …… Nonaqueous solvent introduction pipe 9 …… Water introduction pipe 7a, 8a, 9a …… Valve 10 …… Measuring pipe 11 …… Discharge pipe 11a …… valve
Claims (2)
した後の酸混合液において、残存する各酸の濃度を測定
する方法であって、 洗浄後の酸混合液であるサンプルに還元試薬を加えた上
で、濃度既知の中和滴定試薬により滴定して全酸濃度を
計測し、 前記サンプルを非水溶媒系で濃度既知の置換滴定試薬に
より滴定して硝酸濃度を計測し、 前記全酸濃度と前記硝酸濃度より弗酸濃度を算出するこ
とを特徴とするステンレス鋼酸洗浄液中の硝酸、弗酸の
濃度測定方法。1. A method for measuring the concentration of each remaining acid in an acid mixture after washing stainless steel with a mixture of nitric acid and hydrofluoric acid, which is reduced to a sample which is the acid mixture after washing. After adding the reagent, the total acid concentration is measured by titration with a neutralization titration reagent of known concentration, and the nitric acid concentration is measured by titrating the sample with a displacement titration reagent of known concentration in a non-aqueous solvent system, A method for measuring the concentrations of nitric acid and hydrofluoric acid in a stainless steel acid cleaning solution, which comprises calculating the hydrofluoric acid concentration from the total acid concentration and the nitric acid concentration.
薬を別々に供給するための３つのタンクと、 該反応容器内の液の水素イオン指数を検出するｐＨ検出
器とを有することを特徴とするステンレス鋼酸洗浄液中
の硝酸、弗酸の濃度自動測定装置。2. A reaction container equipped with a stirrer and a discharge pipe, an introduction pipe for supplying a sample to the reaction container, and a reducing reagent, a neutralization titration reagent and a displacement titration reagent are separately supplied to the reaction container. An automatic measuring device for the concentration of nitric acid and hydrofluoric acid in a stainless steel pickling solution, which comprises three tanks for the purpose of the above, and a pH detector for detecting the hydrogen ion index of the solution in the reaction vessel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22437592A JPH0666783A (en) | 1992-08-24 | 1992-08-24 | Method and instrument for measuring concentration of nitric acid and hydrofluoric acid in stainless steel pickling liquid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22437592A JPH0666783A (en) | 1992-08-24 | 1992-08-24 | Method and instrument for measuring concentration of nitric acid and hydrofluoric acid in stainless steel pickling liquid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0666783A true JPH0666783A (en) | 1994-03-11 |
Family
ID=16812774
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22437592A Pending JPH0666783A (en) | 1992-08-24 | 1992-08-24 | Method and instrument for measuring concentration of nitric acid and hydrofluoric acid in stainless steel pickling liquid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0666783A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1986006709A1 (en) * | 1985-05-09 | 1986-11-20 | Tachi-S Co., Ltd. | Seat body |
| WO1988005420A1 (en) * | 1987-01-23 | 1988-07-28 | Tachi-S Co., Ltd. | Trim cover for seat |
| WO2015070478A1 (en) * | 2013-11-15 | 2015-05-21 | 深圳市华星光电技术有限公司 | Potentiometric titration method for mixed acid solution |
| CN104730201A (en) * | 2015-03-04 | 2015-06-24 | 南昌航空大学 | Measurement method for content of hydrofluoric acid in titanium alloy pickling solution |
| CN105158407A (en) * | 2015-10-09 | 2015-12-16 | 天津市捷威动力工业有限公司 | Method for measuring HF content of electrolyte containing LiBOB |
| CN114019088A (en) * | 2021-10-27 | 2022-02-08 | 浙江容跃环保科技有限公司 | Full-automatic device for preparing mixed acid liquid |
-
1992
- 1992-08-24 JP JP22437592A patent/JPH0666783A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1986006709A1 (en) * | 1985-05-09 | 1986-11-20 | Tachi-S Co., Ltd. | Seat body |
| WO1988005420A1 (en) * | 1987-01-23 | 1988-07-28 | Tachi-S Co., Ltd. | Trim cover for seat |
| GB2208354A (en) * | 1987-01-23 | 1989-03-30 | Tachi S Co | Trim cover for seat |
| GB2208354B (en) * | 1987-01-23 | 1990-07-18 | Tachi S Co | Trim covers for seats |
| WO2015070478A1 (en) * | 2013-11-15 | 2015-05-21 | 深圳市华星光电技术有限公司 | Potentiometric titration method for mixed acid solution |
| CN104730201A (en) * | 2015-03-04 | 2015-06-24 | 南昌航空大学 | Measurement method for content of hydrofluoric acid in titanium alloy pickling solution |
| CN105158407A (en) * | 2015-10-09 | 2015-12-16 | 天津市捷威动力工业有限公司 | Method for measuring HF content of electrolyte containing LiBOB |
| CN114019088A (en) * | 2021-10-27 | 2022-02-08 | 浙江容跃环保科技有限公司 | Full-automatic device for preparing mixed acid liquid |
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