This standard is applicable to the determination of iron content in metallic vanadium. Determination range: 0.004 0% to 0.03%. This standard complies with GB 1467-78 "General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products". GB/T 8639.5-1988 Chemical Analysis Method for Vanadium - Determination of Iron Content by Isoamyl Alcohol Extraction Spectrophotometry GB/T8639.5-1988 Standard Download Decompression Password: www.bzxz.net

National Standard of the People's Republic of China
Vanadium- Determination of
iron content--- Isoamyl alcohol extractionspectrophotometric method
This standard is applicable to the determination of iron content in metallic vanadium. Determination range: 0.0040%～0.03%. UDC 669. 292
GB 8639.5--88
This standard complies with GB1467-78 "General Principles and General Provisions for Chemical Analysis Methods for Metallurgical Products". 1
Method Summary
The sample is decomposed with nitric acid and sulfuric acid, and vanadium, iron and other elements are reduced with sodium sulfite and hydroxylamine hydrochloride. The pH is adjusted to 4-6 with sodium acetate, 4,7-diphenyl-1,10-phenanthroline is added for color development, and is extracted with isoamyl alcohol. The absorbance is measured at a wavelength of 540nm on a spectrophotometer. 2 Reagents
The water used for preparing solutions and analysis is double distilled water. 2.1
Isoamyl alcohol.
Nitric acid (1+1), ultrapure.
Sulfuric acid (1+1, ultrapure.
Sodium sulfite solution (6%).
Hydroxyamine hydrochloride solution (10%).
Sodium acetate solution (50%).
Phenanthroline solution (0.01 mol/L): Weigh 0.334 g of o-phenanthroline and dissolve it in 100 mL of anhydrous ethanol and mix well. 2.8www.bzxz.net
Standard iron solution:
2.8.1 Weigh 0.1000 g of pure iron (purity>99.99%), place it in a 100 mL beaker, add 5 mL of aqua regia, heat to dissolve, then add 10 mL of sulfuric acid (p1.84 g/mL) and evaporate until white sulfur trioxide smoke appears, cool, add 50 mL of water, heat to dissolve the salts, and after cooling, transfer it to a 1000 mL volumetric flask and dilute it with water To the mark, mix well. This solution contains 100μg iron in 1mL. 2.8.2 Pipette 10.00mL of the standard iron solution (2.8.1), place it in a 100mL volumetric flask, dilute to the mark with water, and mix well. This solution contains 10μg iron in 1mL.
3 Instrument
Spectrophotometer.
4 Sample
The sample should pass through a 0.351mm sieve.
Approved by China National Nonferrous Metals Industry Corporation on January 11, 1988 and implemented on January 1, 1989
5 Analysis steps
5.1 Sample quantity
Weigh more than 0.5000 of the sample.
5.2 Blank test
Perform a blank test with the sample.
5.3 Determination
GB 8639.5-88
5.3.1 Place the sample (5.1) in a 100mL beaker, add 10mL nitric acid (2.2), cover the beaker, wait for the reaction to slow down, add 10mL sulfuric acid (2.3), heat until sulfuric acid smoke appears for 1 minute, remove and cool, add about 50mL water along the wall of the beaker, heat to dissolve the salt. Remove and cool, transfer to 100 mL volumetric flask, dilute to the mark with water and mix. 5.3.2 Pipette 10.00mL of the test solution (5.3.1) into a 100mL beaker, add 5mL of sodium sulfite solution (2.4), heat to near boiling, add 5mL of hydroxylamine hydrochloride solution (2.5) and continue to heat to near boiling, remove, immediately adjust the pH to 4-6 with sodium acetate solution (2.6), let stand until the blue color disappears, and cool. Transfer to a 125mL separatory funnel so that its volume is about 50-60mL, mix well, add 1.0mL of 4,7-diphenyl-1,10-phenanthroline solution (2.7), and mix. Immediately add 10.00mL of isoamyl alcohol (2.1), shake thoroughly for 1min, let stand to separate, discard the aqueous phase, and filter the organic phase into 1 cm colorimetric tube. 5.3.3 Measure the absorbance at a wavelength of 540nm on the spectrophotometer with water as the reference, subtract the absorbance of the accompanying sample blank, and find the corresponding iron content from the working curve.
5.4 Drawing of working curve
Take 5 portions of the accompanying sample blank solution. 10.00mL each, place them in 100mL beakers, add 0, 0.20, 0.50, 1.00, 1.50mL of the iron standard solution (2.8.2), add 5mL of sodium sulfite solution (2.4), and proceed as in 5.3.2. Measure the absorbance at a wavelength of 540nm on the spectrophotometer with water as the reference, subtract the absorbance of the accompanying sample blank, and draw the working curve with the iron content as the horizontal axis and the absorbance as the vertical axis.
6 Calculation of analysis results
Calculate the percentage of iron according to formula (1):
Fe(%) = m ×10-1
Wherein: m,—
The amount of iron found from the working curve, ug; the amount of sample, ug,
—the sample split ratio.
The analysis results are expressed to four decimal places. 7 Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table. Table 1
0. 004 0~~0. 015
>0. 015~0, 030
Additional remarks:
This standard was drafted by Jinzhou Ferroalloy Plant. This standard was drafted by Nanjing Ferroalloy Plant.
The main drafters of this standard are Dai Xiuying and Ge Shunying. 330
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