JP3290580B2 - Analysis method of iron ion concentration in pickling liquid in stainless steel pickling process - Google Patents
Analysis method of iron ion concentration in pickling liquid in stainless steel pickling processInfo
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- JP3290580B2 JP3290580B2 JP34290895A JP34290895A JP3290580B2 JP 3290580 B2 JP3290580 B2 JP 3290580B2 JP 34290895 A JP34290895 A JP 34290895A JP 34290895 A JP34290895 A JP 34290895A JP 3290580 B2 JP3290580 B2 JP 3290580B2
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- iron
- concentration
- pickling
- solution
- aqueous solution
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Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ステンレス鋼帯な
どステンレス鋼の酸洗に用いられる酸洗液中の鉄イオン
濃度の分析方法に関する。The present invention relates to a method for analyzing the concentration of iron ions in a pickling solution used for pickling stainless steel such as a stainless steel strip.
【０００２】[0002]
【従来の技術】熱間加工後のステンレス鋼帯の表面に存
在する酸化物を除去する方法の一つとして酸洗法があ
る。この酸洗方法においては、弗酸および硝酸を含む混
酸の水溶液が用いられる場合が一般的である。さらに、
上記混酸水溶液による酸洗工程の前工程、後工程におい
て硫酸水溶液による酸洗工程を設けることが必要な場合
がある。2. Description of the Related Art Pickling is one method for removing oxides present on the surface of a stainless steel strip after hot working. In this pickling method, an aqueous solution of a mixed acid containing hydrofluoric acid and nitric acid is generally used. further,
In some cases, it is necessary to provide a pickling step using a sulfuric acid aqueous solution in a step before and after the pickling step using the mixed acid aqueous solution.
【０００３】このような酸洗液の酸洗能力は、その中に
含まれる遊離弗酸、遊離硝酸、遊離硫酸の濃度に依存す
る。すなわち、ステンレス鋼帯を上記酸洗液で酸洗を行
うにつれて、ステンレス鋼帯表面より鉄イオン、その他
の金属イオンが水酸化物として溶出し、それと共に遊離
弗酸、遊離硝酸、遊離硫酸の濃度は減少し、酸洗液の酸
洗能力は低下する。[0003] The pickling ability of such a pickling solution depends on the concentration of free hydrofluoric acid, free nitric acid and free sulfuric acid contained therein. That is, as the stainless steel strip is pickled with the above pickling solution, iron ions and other metal ions are eluted from the stainless steel strip surface as hydroxides, and the concentration of free hydrofluoric acid, free nitric acid, and free sulfuric acid is also increased. And the pickling ability of the pickling solution decreases.
【０００４】このため、前記した混酸水溶液による酸洗
工程と硫酸水溶液による酸洗工程の両者を設けたステン
レス鋼帯の酸洗工程においては、遊離弗酸濃度、遊
離硝酸濃度、遊離硫酸濃度、混酸水溶液中の鉄イオ
ン濃度、硫酸水溶液中の鉄イオン濃度を分析する必要
がある。この場合、従来の分析方法では、は鉄−アセ
チルアセトン錯体退色吸光光度法により、、は水酸
化ナトリウム水溶液による中和滴定法により、は鉄−
サリチル酸錯体吸光光度法により、は過マンガン酸カ
リウムによる滴定法により分析を行っている。[0004] Therefore, in the pickling process of a stainless steel strip provided with both the above-mentioned pickling process using a mixed acid aqueous solution and the pickling process using a sulfuric acid aqueous solution, the concentration of free hydrofluoric acid, the concentration of free nitric acid, the concentration of free sulfuric acid, It is necessary to analyze the iron ion concentration in the aqueous solution and the iron ion concentration in the sulfuric acid aqueous solution. In this case, according to the conventional analysis method, iron-acetylacetone complex is subjected to fading absorption spectrophotometry;
Analysis is performed by salicylic acid complex spectrophotometry and by titration with potassium permanganate.
【０００５】また、一般に、本発明の目的である硫酸鉄
に帰属する鉄イオンの分析方法としては、以下の方法が
よく知られている。すなわち、前記の酸洗工程における
従来の分析方法として、硫酸鉄含有硫酸水溶液中にＯ−
フェナントロリンの希釈液を添加し、過マンガン酸カリ
ウムを用いて滴定を行い、終点を紫から赤色に変色した
点と規定して、使用した過マンガン酸カリウムの量から
硫酸鉄の濃度を測定する方法や、硫酸鉄含有硫酸水溶液
中に過マンガン酸カリウムを滴下しつつ、自動電位差計
により終点を自動検知し、使用した過マンガン酸カリウ
ムの量から硫酸鉄の濃度を測定する方法がある。In general, the following method is well known as a method for analyzing iron ions belonging to iron sulfate, which is the object of the present invention. That is, as a conventional analysis method in the above pickling step, O-
A method for measuring the concentration of iron sulfate from the amount of potassium permanganate used, by adding a dilute solution of phenanthroline, performing titration with potassium permanganate, and defining the end point as a point at which the color changed from purple to red. Alternatively, there is a method in which an end point is automatically detected by an automatic potentiometer while potassium permanganate is dropped into an aqueous solution of sulfuric acid containing iron sulfate, and the concentration of iron sulfate is measured from the amount of potassium permanganate used.
【０００６】しかし、前記の酸洗工程における従来の分
析方法においては、各々の成分濃度を別個の方法で分析
していたため分析装置が大型となり、これが自動分析装
置の開発の阻害要因ともなっていた。However, in the conventional analysis method in the above pickling step, each component concentration is analyzed by a separate method, so that the analyzer becomes large, which has been a hindrance to the development of an automatic analyzer.
【０００７】[0007]
【発明が解決しようとする課題】本発明は、前記問題点
を解決し、ステンレス鋼酸洗工程における酸洗液中の鉄
イオン濃度、特に硫酸酸洗液中の鉄イオン濃度および弗
酸・硝酸混酸酸洗液中の鉄イオン濃度の両者を、同一の
分析方法で、小型化した自動分析装置で測定可能な分析
方法を提供することを目的とする。DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and provides an iron ion concentration in a pickling solution in a stainless steel pickling process, in particular, an iron ion concentration in a sulfuric acid pickling solution and hydrofluoric acid / nitric acid. It is an object of the present invention to provide an analysis method capable of measuring both the iron ion concentration in a mixed pickling solution with a downsized automatic analyzer using the same analysis method.
【０００８】[0008]
【課題を解決するための手段】本発明は、硫酸水溶液お
よび弗酸・硝酸混酸水溶液による酸洗工程を有するステ
ンレス鋼酸洗工程における酸洗液中の鉄イオン濃度の分
析方法であって、前記硫酸酸洗工程で循環する硫酸水溶
液試料中に過酸化水素水を添加した後得られる水溶液
と、前記混酸酸洗工程で循環する混酸水溶液試料の両者
を、各々、鉄−サリチル酸錯体吸光光度法により分析す
ることを特徴とするステンレス鋼酸洗工程における酸洗
液中の鉄イオン濃度の分析方法である。SUMMARY OF THE INVENTION The present invention provides a method for analyzing the iron ion concentration in a pickling solution in a stainless steel pickling process having a pickling process using an aqueous sulfuric acid solution and an aqueous mixed solution of hydrofluoric acid and nitric acid. Both the aqueous solution obtained after adding the hydrogen peroxide solution to the sulfuric acid aqueous solution sample circulating in the sulfuric acid pickling step and the mixed acid aqueous solution sample circulated in the mixed acid pickling step were each subjected to iron-salicylic acid complex spectrophotometry. This is a method for analyzing the concentration of iron ions in a pickling solution in a stainless steel pickling step, characterized by analyzing.
【０００９】前記した本発明においては、添加する過酸
化水素水の濃度が、0.06〜0.25 w/v％であり、過酸化水
素水添加後、前記吸光光度法による分析迄の試料の保存
時間が３分以内であることが好ましい。In the above-mentioned present invention, the concentration of the hydrogen peroxide solution to be added is 0.06 to 0.25 w / v%, and the storage time of the sample after the addition of the hydrogen peroxide solution until the analysis by the absorptiometric method. Preferably, it is within 3 minutes.
【００１０】[0010]
【発明の実施の形態】以下、本発明をより詳細に説明す
る。本発明者らは、前記問題点を解決するために、鋭意
検討し、混酸水溶液中の鉄濃度と同じ分析方法が可能な
硫酸水溶液中の硫酸鉄の分析方法を模索した。このた
め、前記した混酸水溶液による酸洗工程と硫酸水溶液に
よる酸洗工程の両者を設けたステンレス鋼帯の酸洗工程
における混酸水溶液循環槽（以下混酸槽と記す）および
硫酸水溶液循環槽（以下硫酸槽と記す）の混酸水溶液中
および硫酸水溶液中の鉄イオンの形態およびその濃度を
分析した結果、下記の結果が得られた。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. In order to solve the above-mentioned problems, the present inventors have conducted intensive studies and sought a method for analyzing iron sulfate in a sulfuric acid aqueous solution, which method can perform the same analysis method as the iron concentration in a mixed acid aqueous solution. For this reason, a mixed acid aqueous solution circulating tank (hereinafter referred to as a mixed acid tank) and a sulfuric acid aqueous solution circulating tank (hereinafter referred to as a sulfuric acid aqueous solution) in the pickling step of a stainless steel strip provided with both the above-described pickling step using a mixed acid aqueous solution and the pickling step using a sulfuric acid aqueous solution. As a result of analyzing the form and concentration of iron ions in the mixed acid aqueous solution and the aqueous sulfuric acid solution (hereinafter referred to as a tank), the following results were obtained.
【００１１】混酸槽における鉄イオンの形態および各濃
度： ２価の鉄・・・ 0.09 wt％、３価の鉄・・・ 3.01 wt％ 硫酸Ｉ槽における鉄イオンの形態および各濃度： ２価の鉄・・・ 5.4 wt％、３価の鉄・・・ 0.06 wt％ 硫酸II槽における鉄イオンの形態および各濃度： ２価の鉄・・・ 6.8 wt％、３価の鉄・・・ 0.09 wt％ これにより、混酸水溶液中では鉄イオンは３価の鉄イオ
ンが支配的であり、硫酸水溶液中では鉄イオンは２価の
鉄イオンが支配的であることが分かった。Form and each concentration of iron ions in the mixed acid tank: divalent iron: 0.09 wt%, trivalent iron: 3.01 wt% Form of iron ions and each concentration in the sulfuric acid I tank: divalent iron Iron: 5.4 wt%, trivalent iron: 0.06 wt% Form and concentration of iron ions in the sulfuric acid II tank: divalent iron: 6.8 wt%, trivalent iron: 0.09 wt % From this, it was found that in the mixed acid aqueous solution, the iron ion is dominated by trivalent iron ion, and in the sulfuric acid aqueous solution, the iron ion is dominated by divalent iron ion.
【００１２】以上得られた結果から、硫酸水溶液中の２
価の鉄イオンを３価の鉄イオンに酸化することが可能で
あれば、混酸水溶液中の鉄イオン濃度と同様の分析方
法、すなわち前記した鉄−サリチル酸錯体吸光光度法に
より硫酸水溶液中の２価の鉄イオン濃度の分析が可能と
なる。本発明によれば、硫酸鉄含有硫酸水溶液中に過酸
化水素水を添加し、２価の鉄イオンを３価の鉄イオンと
することにより、ステンレス酸洗工程における硫酸水溶
液中の鉄イオン濃度と、混酸水溶液中の鉄イオン濃度
を、同一の分析方法で分析することが可能となった。From the results obtained above, it can be seen that 2%
If it is possible to oxidize the divalent iron ion to the trivalent iron ion, the same analysis method as the iron ion concentration in the mixed acid aqueous solution, that is, the divalent iron ion in the sulfuric acid aqueous solution can be obtained by the above-described iron-salicylic acid complex absorption spectrophotometry. Analysis of the iron ion concentration of the iron. According to the present invention, a hydrogen peroxide solution is added to an aqueous solution of sulfuric acid containing iron sulfate to convert divalent iron ions into trivalent iron ions. The iron ion concentration in the mixed acid aqueous solution can be analyzed by the same analysis method.
【００１３】本発明における硫酸鉄含有硫酸水溶液に添
加する過酸化水素水の濃度は、0.06〜0.25 w/v％である
ことが好ましい。これは、0.06 w/v％未満では鉄イオン
濃度が高くなるにしたがい、２価の鉄イオンの３価の鉄
イオンへの変換率が低下し、逆に0.25 w/v％超えの場合
退色効果が大きくなり、３価の鉄イオンへの変換率が試
料の保存時間と共に低下してしまい、Ｆｅ2+イオンの濃
度分析値の精度の低下が生じるためである。The concentration of the hydrogen peroxide solution added to the aqueous solution of sulfuric acid containing iron sulfate in the present invention is preferably 0.06 to 0.25 w / v%. This is because when the iron ion concentration increases below 0.06 w / v%, the conversion rate of divalent iron ions to trivalent iron ions decreases, and conversely, when the iron ion concentration exceeds 0.25 w / v%, the fading effect occurs. And the conversion rate to trivalent iron ions decreases with the storage time of the sample, and the accuracy of the concentration analysis value of Fe 2+ ions decreases.
【００１４】前記退色効果によるＦｅ2+イオンの濃度分
析値の精度の低下の防止のために、本発明においては、
過酸化水素水を添加した分析用試料は、過酸化水素水添
加後３分以内に、鉄−サリチル酸錯体吸光光度法により
測定することが好ましい。In order to prevent a decrease in the accuracy of the analytical value of the concentration of Fe 2+ ions due to the fading effect, in the present invention,
The analysis sample to which the hydrogen peroxide solution has been added is preferably measured by iron-salicylic acid complex absorption spectrophotometry within 3 minutes after the addition of the hydrogen peroxide solution.
【００１５】[0015]
【実施例】以下、本発明を実施例に基づいて具体的に説
明する。なお、以下、本実施例においては、２価の鉄の
３価の鉄への変換率を、変換率と略記する。 （実施例１）Ｆｅ2+イオン濃度（以下Ｆｅ2+濃度と記
す）を変えた２価の鉄の標準サンプル液の各々に、濃度
の異なる過酸化水素水を添加し、鉄−サリチル酸錯体吸
光光度法により、変換率を調査した。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. Hereinafter, in the present embodiment, the conversion rate of divalent iron to trivalent iron is abbreviated as conversion rate. (Example 1) Hydrogen peroxide solutions having different concentrations were added to each of divalent iron standard sample solutions having different Fe 2+ ion concentrations (hereinafter referred to as Fe 2+ concentrations), and iron-salicylic acid complex absorption was performed. The conversion was investigated by photometry.
【００１６】Ｆｅ3+イオンはサリチル酸と紫色のキレー
ト錯化合物を形成するため、これを利用して波長 520nm
の光を用いて吸光光度法によりＦｅ3+イオン濃度（以下
Ｆｅ 3+濃度と記す）を測定する。具体的な測定手順の例
を、下記および図１に示す。 （１）サリチル酸呈色液の調製： (a)0.45M/lのKCl と0.06N のHCl とから成る緩衝液と、
(b) 2.4w/v％硝酸アルミニウムから成るマスキング剤
と、(c) 0.5w/v％サリチル酸ナトリウムから成る呈色液
とを等量ずつ混合し、水で10倍に希釈する。Fe3+The ions are salicylic acid and purple
To form a complex compound with a wavelength of 520 nm
By the spectrophotometric method using3+Ion concentration (below
Fe 3+Concentration). Example of specific measurement procedure
Is shown below and in FIG. (1) Preparation of salicylic acid color solution: (a) a buffer solution consisting of 0.45 M / l KCl and 0.06 N HCl;
(b) Masking agent consisting of 2.4 w / v% aluminum nitrate
And (c) a color solution comprising 0.5% w / v sodium salicylate
Are mixed in equal amounts, and diluted 10 times with water.
【００１７】（２）分析用試料の調製：測定試料33μl
、過酸化水素水１ml、サリチル酸呈色液10ml、希釈水9
0mlをメスフラスコに分取し、１分間混合・攪拌する。 （３）吸光光度法による測定：（２）で得られた溶液の
一部を、石英ガラス製吸収セル（５mm）に採取し、波長
520nmにおける吸光度を測定し、予め作成した検量線に
より試料中のＦｅ3+濃度を求める。(2) Preparation of sample for analysis: 33 μl of sample to be measured
, 1 ml of hydrogen peroxide solution, 10 ml of salicylic acid color solution, 9 dilution water
Dispense 0 ml into a volumetric flask, mix and stir for 1 minute. (3) Measurement by absorption spectrophotometry: A part of the solution obtained in (2) was collected in a quartz glass absorption cell (5 mm), and the wavelength was measured.
The absorbance at 520 nm is measured, and the Fe 3+ concentration in the sample is determined from a previously prepared calibration curve.
【００１８】図２、図３および図４に２価の鉄の標準サ
ンプル液（Ｆｅ2+濃度：2.5wt ％、5.0wt ％、10.0wt
％）に濃度の異なる過酸化水素水を添加した時の、過酸
化水素水の濃度と変換率との関係を示す。図２、図３お
よび図４から、Ｆｅ2+濃度が低い場合は、過酸化水素水
の濃度が低い場合でも変換率は95％以上が達成されるが
（図２）、Ｆｅ2+濃度がステンレス鋼帯の酸洗工程にお
ける硫酸槽硫酸水溶液中のＦｅ2+濃度（５〜10wt％）程
度の場合は、過酸化水素水の濃度が 0.03w/v％では変換
率は44％と低下することが示される（図４）。FIGS. 2, 3 and 4 show a standard sample solution of divalent iron (Fe 2+ concentration: 2.5 wt%, 5.0 wt%, 10.0 wt%).
%) Shows the relationship between the concentration of the hydrogen peroxide solution and the conversion rate when hydrogen peroxide solutions having different concentrations are added. 2, 3 and 4, when Fe 2+ concentration is low, the conversion rate even when the low concentration of hydrogen peroxide is achieved at least 95% (Fig. 2), the Fe 2+ concentration When the concentration of Fe 2+ in the sulfuric acid aqueous solution in the sulfuric acid tank (about 5 to 10 wt%) in the pickling process of the stainless steel strip is about 0.03 w / v%, the conversion rate decreases to 44%. (FIG. 4).
【００１９】すなわち、変換率80％以上を達成するため
には、硫酸水溶液へ添加する過酸化水素水の濃度は、0.
06 w/v％以上であることが好ましい（図２〜４）。一
方、図４に示されるように、過酸化水素水の濃度が 0.2
5w/v％の場合、過酸化水素水添加後の試料の保存時間と
ともに変換率が低下し、過酸化水素水の濃度の上限値は
0.25 w/v％であることが好ましい。That is, in order to achieve a conversion rate of 80% or more, the concentration of the hydrogen peroxide solution added to the aqueous sulfuric acid solution should be 0.1%.
It is preferably at least 06 w / v% (FIGS. 2 to 4). On the other hand, as shown in FIG.
In the case of 5 w / v%, the conversion rate decreases with the storage time of the sample after adding the hydrogen peroxide solution, and the upper limit of the concentration of the hydrogen peroxide solution is
Preferably, it is 0.25 w / v%.
【００２０】（実施例２）次に、前記の実験で明らかに
なった退色効果の影響を調べるために、Ｆｅ3+濃度を変
えた３価の鉄の標準サンプル液の各々に、濃度が0.125w
t ％の過酸化水素水を添加し、過酸化水素水添加後の試
料の保存時間が分析値に及ぼす影響を調べた。Example 2 Next, in order to examine the effect of the fading effect clarified in the above experiment, each of the trivalent iron standard sample solutions having different Fe 3+ concentrations had a concentration of 0.125. w
The addition of t% of hydrogen peroxide solution and the effect of the storage time of the sample after the addition of the hydrogen peroxide solution on the analysis value were examined.
【００２１】図５に得られた結果を示す。図５における
縦軸の（鉄濃度分析値／真の鉄濃度）×100 ％の指標に
おいて、鉄濃度分析値は実施例１で示した鉄−サリチル
酸錯体吸光光度法により分析した分析値を示し、真の鉄
濃度は薬品の保証値より算出した値による分析値であ
る。なお、図５において、試料の保存時間が短時間の場
合、鉄濃度分析値が真の鉄濃度より若干高い値となって
いるが、これは存在する不純物としての２価の鉄イオン
が３価に変換されたためと推定される。FIG. 5 shows the obtained results. In the index of (iron concentration analysis value / true iron concentration) × 100% on the vertical axis in FIG. 5, the iron concentration analysis value indicates the analysis value analyzed by the iron-salicylic acid complex absorption spectrophotometric method shown in Example 1. The true iron concentration is an analysis value based on a value calculated from the guaranteed value of the chemical. In FIG. 5, when the storage time of the sample is short, the iron concentration analysis value is slightly higher than the true iron concentration. It is estimated that it has been converted to.
【００２２】図５に示される結果から、過酸化水素水添
加後の試料の保存時間が３分を超えると、鉄−サリチル
酸錯体吸光光度法による分析値が低下し、試料の保存時
間は３分以内が好ましいことが分かった。以上の実施例
１および実施例２から、ステンレス鋼帯の酸洗工程に
おける硫酸槽の硫酸水溶液中のＦｅ2+イオンを主体とす
る鉄イオンの分析方法としては、過酸化水素水添加・鉄
−サリチル酸錯体吸光光度法が好適であること、この
場合、添加する過酸化水素水の濃度は、0.06〜0.25 w/v
％の範囲が好適であり、過酸化水素水添加後、前記吸光
光度法による分析迄の試料の保存時間が３分以内である
ことが好ましいことが分かった。From the results shown in FIG. 5, when the storage time of the sample after addition of the hydrogen peroxide solution exceeds 3 minutes, the analytical value by the iron-salicylic acid complex absorption spectrophotometric method decreases, and the storage time of the sample is 3 minutes. Was found to be preferable. From the above Examples 1 and 2, the method of analyzing iron ions mainly composed of Fe 2+ ions in a sulfuric acid aqueous solution in a sulfuric acid tank in a pickling process of a stainless steel strip is as follows. That the salicylic acid complex absorption spectrophotometry is suitable, in this case, the concentration of the added hydrogen peroxide solution is 0.06 to 0.25 w / v
% Was suitable, and it was found that the storage time of the sample after the addition of the aqueous hydrogen peroxide and before the analysis by the absorption spectrophotometry was preferably within 3 minutes.
【００２３】（実施例３）本発明による分析法を用い
て、前記した混酸水溶液による酸洗工程と硫酸水溶液に
よる酸洗工程の両者を設けたステンレス鋼帯の酸洗工程
における硫酸槽の硫酸水溶液中の鉄イオン濃度を分析し
た。図６に、従来の過マンガン酸カリウムによる滴定法
（手分析）によって得られた鉄イオン濃度と、本発明に
よる過酸化水素水添加・鉄−サリチル酸錯体吸光光度法
により分析した鉄イオン濃度を対比して示す。Example 3 An aqueous sulfuric acid solution in a sulfuric acid tank in a stainless steel strip pickling step provided with both the above-mentioned pickling step using an aqueous mixed acid solution and the pickling step using an aqueous sulfuric acid solution using the analysis method according to the present invention. The iron ion concentration in was analyzed. FIG. 6 shows a comparison between the iron ion concentration obtained by the conventional titration method using potassium permanganate (manual analysis) and the iron ion concentration analyzed by the hydrogen peroxide solution added / iron-salicylic acid complex absorption spectrophotometry according to the present invention. Shown.
【００２４】なお、この場合の過酸化水素水の濃度は、
0.125w/v％、前記した試料の保存時間は、３分以内とし
た。また、本実施例においては、本発明による分析は、
試料採取、分析用試料の調製、測定、検量線に基づく鉄
濃度の算出は全て自動測定装置により行った。図６か
ら、本発明の方法による分析値は、実操業において、従
来法による分析値と問題のないレベルで一致しているこ
とが分かる。In this case, the concentration of the hydrogen peroxide solution is as follows:
The storage time of the sample was 0.125 w / v% and the storage time was 3 minutes or less. In this example, the analysis according to the present invention
Sampling, preparation of the sample for analysis, measurement, and calculation of the iron concentration based on the calibration curve were all performed by an automatic measuring device. From FIG. 6, it can be seen that the analytical values according to the method of the present invention match the analytical values according to the conventional method at an acceptable level in actual operation.
【００２５】（実施例４）実施例３の酸洗工程の混酸槽
の混酸水溶液中の鉄イオン濃度を、鉄−サリチル酸錯体
吸光光度法により分析した。なお、この場合は、実施例
３の自動測定装置の分析用試料の調製装置において、試
料溶液中に、弗化鉄イオンを分解するために硝酸アルミ
ニウム溶液を添加、混合し、分析を行った。Example 4 The iron ion concentration in the mixed acid aqueous solution in the mixed acid tank in the pickling step of Example 3 was analyzed by an iron-salicylic acid complex absorption spectrophotometry. In this case, an analysis was performed by adding and mixing an aluminum nitrate solution to the sample solution in the sample preparation apparatus of the automatic measurement apparatus of Example 3 in order to decompose iron fluoride ions.
【００２６】鉄−サリチル酸錯体吸光光度法により分析
した混酸水溶液中のＦｅ3+濃度30.6wt％は、精度保証さ
れている別の吸光光度計により分析した鉄濃度30.4wt％
とほぼ一致した。The Fe 3+ concentration of 30.6 wt% in the mixed acid aqueous solution analyzed by the iron-salicylic acid complex absorption spectrophotometry was 30.4 wt% of the iron concentration analyzed by another absorption spectrophotometer whose accuracy was guaranteed.
Almost matched.
【００２７】[0027]
【発明の効果】本発明によれば、硫酸水溶液酸洗工程お
よび弗酸・硝酸混酸水溶液酸洗工程を有するステンレス
鋼酸洗工程における硫酸水溶液中の鉄イオン濃度と弗酸
・硝酸混酸水溶液中の鉄イオン濃度の両者を、同一の分
析方法で、精度良く自動分析が可能となり、またこの結
果、自動分析装置全体の小型化が可能となり、その工業
的価値は大きい。According to the present invention, the iron ion concentration in a sulfuric acid aqueous solution and the concentration of iron ion in a hydrofluoric acid / nitric acid mixed aqueous solution in a stainless steel pickling process having a sulfuric acid aqueous solution pickling step and a hydrofluoric / nitric acid mixed acid aqueous pickling step. Automatic analysis of both the iron ion concentration and the same analysis method can be performed with high accuracy, and as a result, the entire automatic analyzer can be reduced in size, and its industrial value is great.
【図１】本発明の具体的な分析手順を示す工程図であ
る。FIG. 1 is a process chart showing a specific analysis procedure of the present invention.
【図２】過酸化水素水の濃度と変換率との関係を示すグ
ラフである。FIG. 2 is a graph showing a relationship between a concentration of a hydrogen peroxide solution and a conversion rate.
【図３】過酸化水素水の濃度と変換率との関係を示すグ
ラフである。FIG. 3 is a graph showing a relationship between a concentration of a hydrogen peroxide solution and a conversion rate.
【図４】過酸化水素水の濃度と変換率との関係を示すグ
ラフである。FIG. 4 is a graph showing a relationship between a concentration of a hydrogen peroxide solution and a conversion rate.
【図５】過酸化水素水添加後の試料の保存時間と分析値
の関係を示すグラフである。FIG. 5 is a graph showing a relationship between a storage time of a sample after addition of a hydrogen peroxide solution and an analysis value.
【図６】ステンレス鋼帯酸洗工程における硫酸水溶液中
の鉄イオン濃度の、本発明方法による分析値と従来法に
よる分析値との対比を示すグラフである。FIG. 6 is a graph showing a comparison between an analytical value obtained by the method of the present invention and an analytical value obtained by the conventional method, for the iron ion concentration in the aqueous sulfuric acid solution in the pickling step of a stainless steel strip.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平７−294509（ＪＰ，Ａ) 特開 昭51−95939（ＪＰ，Ａ) 特開 昭57−39180（ＪＰ，Ａ) 特開 平２−183146（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01N 31/00 C23G 1/08 C23G 3/02 G01N 21/77 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-7-294509 (JP, A) JP-A-51-95939 (JP, A) JP-A-57-39180 (JP, A) JP-A-2- 183146 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) G01N 31/00 C23G 1/08 C23G 3/02 G01N 21/77
Claims (2)
による酸洗工程を有するステンレス鋼酸洗工程における
前記酸洗液中の鉄イオン濃度の分析方法であって、前記
硫酸酸洗工程で循環する硫酸水溶液試料中に過酸化水素
水を添加した後得られる水溶液と、前記混酸酸洗工程で
循環する混酸水溶液試料の両者を、各々、鉄−サリチル
酸錯体吸光光度法により分析することを特徴とするステ
ンレス鋼酸洗工程における酸洗液中の鉄イオン濃度の分
析方法。1. A method for analyzing the concentration of iron ions in a pickling solution in a stainless steel pickling process having a pickling process using a sulfuric acid aqueous solution and a hydrofluoric acid / nitric acid mixed acid aqueous solution, wherein the iron ions are circulated in the sulfuric acid pickling process. An aqueous solution obtained after adding a hydrogen peroxide solution to a sulfuric acid aqueous solution sample and a mixed acid aqueous solution sample circulating in the mixed acid pickling step are each analyzed by an iron-salicylic acid complex absorption spectrophotometric method. Method for analyzing iron ion concentration in pickling liquid in stainless steel pickling process.
0.25 w/v％であり、過酸化水素水添加後、前記吸光光度
法による分析迄の試料の保存時間が３分以内であること
を特徴とする請求項１記載のステンレス鋼酸洗工程にお
ける酸洗液中の鉄イオン濃度の分析方法。2. The concentration of the hydrogen peroxide solution to be added is 0.06 to 0.06.
2. The stainless steel pickling process according to claim 1, wherein the storage time of the sample from the addition of the hydrogen peroxide solution to the analysis by the spectrophotometric method is within 3 minutes after the addition of the hydrogen peroxide solution. Analysis method for iron ion concentration in washing liquid.
Priority Applications (1)
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|---|---|---|---|
| JP34290895A JP3290580B2 (en) | 1995-12-28 | 1995-12-28 | Analysis method of iron ion concentration in pickling liquid in stainless steel pickling process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34290895A JP3290580B2 (en) | 1995-12-28 | 1995-12-28 | Analysis method of iron ion concentration in pickling liquid in stainless steel pickling process |
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| Publication Number | Publication Date |
|---|---|
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