GB/T 8639.4-1988 Chemical analysis of vanadium - O-phenanthroline photometric method for the determination of iron content

This standard is applicable to the determination of iron content in metallic vanadium. Determination range: 0.030% to 0.30%. This standard complies with GB 1467-78 "General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products". GB/T 8639.4-1988 Chemical Analysis Method for Vanadium - Determination of Iron Content by O-Phenanthroline Photometric Method GB/T8639.4-1988 Standard Download Decompression Password: www.bzxz.net

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Vanadium -- Determination of iron content Phenanthrline spectrophotometric method
Vanadium -- Determination of iron content Phenanthrline spectrophotometric method This standard is applicable to the determination of iron content in metallic vanadium. Determination range: 0.030%~~0.30%. UDC 669. 292
GB8639.4-88
This standard complies with GB1467-78 "General Principles and General Provisions of Standards for Chemical Analysis Methods of Metallurgical Products". 1 Method Summary
The sample is decomposed with nitric acid-sulfuric acid, and trivalent iron is reduced to divalent with hydroxylamine hydrochloride, while pentavalent vanadium is reduced to tetravalent. At pH 5~~6, o-phenanthroline and iron () form a cuminous red complex, and its absorbance is measured at a wavelength of 510nm on a spectrophotometer. 2 Reagents
2.1 Nitric acid (1+1).
2.2 Sulfuric acid (1+1).
2.3 Hydroxylamine hydrochloride solution (10%).
2.4 Acetic acid-ammonium acetate buffer solution (pH=6): Weigh 50g ammonium acetate and dissolve it in 40mL water, add 1mL glacial acetic acid, dilute to 100mL with water, and mix well.
2.5 O-phenanthroline solution (0.5%): Weigh 0.5g o-phenanthroline and dissolve it in 10mL anhydrous ethanol, dilute to 100mL with water, and mix well.
2.6 Iron standard solution:
2.6.1 Weigh 0.1000g pure iron (purity>99.99%), place it in a 100mL beaker, add 5mL aqua regia, heat to dissolve, then add 10mL sulfuric acid to evaporate until white sulfur trioxide smoke appears, cool, add 50mL water, heat to dissolve the salts, and cool. Transfer to a 100mL volumetric flask, dilute to the mark with water, and mix. This solution contains 100 μg of iron in 1mL. 2.6.2 Transfer 10.00mL of the standard iron solution (2.6.1) to a 100mL volumetric flask, dilute to the mark with water, and mix. This solution contains 10μg of iron in 1mL.
3 Instrument
Spectrophotometer.
4 Sample
The sample should pass through a 0.351mm sieve.
5 Analysis steps
5.1 Sample quantity
Weigh 0.2000g of sample.
China Nonferrous Metals Industry CorporationApproved on January 11, 1988, implemented on January 1, 1989
5.2 Blank test
Perform a blank test with the sample.
5.3 Determination
GB 8639.4—88
5.3.1 Place the sample (5.1) in a 100mL beaker, add 5mL nitric acid (2.1), cover with blood, add 10mL sulfuric acid (2.2) after the reaction slows down, heat until sulfuric acid smoke appears for 1min, remove and cool, add 50mL water, heat to dissolve the salt, remove and cool, transfer to a 100mL volumetric flask, dilute to the mark with water, and mix. 5.3.2 Transfer 10.00mL of the test solution (5.3.1) to a 50mL volumetric flask, add 5mL hydroxylamine hydrochloride solution (2.3), heat in a boiling water bath for 2-3min, remove, immediately add 10mL acetic acid-ammonium acetate buffer solution (2.4), shake until the blue color disappears completely, and immediately cool to room temperature with running water.
5.3.3 Add 10mL of o-phenanthroline solution (2.5), dilute to the mark with water, and mix. Transfer part of the solution into a 2cm colorimetric tube. 5.3.4 Take the blank solution accompanying the sample as a reference, measure its absorbance at a wavelength of 510nm on a spectrophotometer, and find the corresponding amount of iron from the working curve.
5.4 Drawing of the working curve
Take five portions of the blank solution accompanying the sample, 10.00mL each, and place them in 50mL volumetric flasks respectively, add 0, 1.00, 3.00, 5.00, and 7.00mL of the iron standard solution (2.6.2), and add 5mL of hydroxylamine hydrochloride solution (2.3), and proceed as per 5.3.2~~5.3.3. Take the zero concentration solution as a reference, and measure its absorbance at a wavelength of 510nm on a spectrophotometer. With the amount of iron as the horizontal axis and the absorbance as the vertical axis, draw a working curve.
6 Calculation of analysis results
Calculate the percentage of iron according to formula (1):
Fe(%) = m ×10-
Wherein: m.—
The amount of iron found from the working curve, ug; m. Sample volume, g;
T——Test solution split ratio.
Analysis results are expressed to two decimal places. 7 Allowable difference
× 100
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table: Iron
0.030~0.12
>0. 12 ~～~0. 30
Additional notes:
This standard was drafted by Jinzhou Ferroalloy Factory. This standard was drafted by Nanjing Ferroalloy Factory.
The main drafters of this standard are Dai Xiuying and Ge Shunying. 328
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