GB/T 8639.3-1988 Chemical analysis of vanadium - CAS-TPC photometric method for determination of aluminum content
Some standard content:
National Standard of the People's Republic of China
Vanadium- Determination of
aluminium content-- CAS-TPC
spectrophotometric method
This standard is applicable to the determination of aluminum content in metallic vanadium. Determination range: 0.003%～0.10%. UDC 669. 292
GB 8639.388
This standard complies with GB1467--78 "General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products". Method summary
The sample was dissolved in nitric acid and sulfuric acid. Under the acidity of 0.6 mol/L sulfuric acid, vanadium, iron and other elements were extracted and separated using copper iron reagent-chloroform. In the acetic acid-sodium acetate medium of pH 5.8, chrome blue S and tetradecylpyridine chloride were added to make it color with aluminum, and its absorbance was measured at a wavelength of 630 nm on a spectrophotometer.
2 Reagents
The water used for preparing solutions and analysis was double distilled water. 2.1 Chloroform.
2.2 Nitric acid (p1.42g/mL), high purity. 2.3 Nitric acid (1+1), high purity.
Sulfuric acid (1+1), high purity.
2.5 Hydrochloric acid (1+19), high purity.
2.6 Ascorbic acid solution (1%), prepared before use. 2.7www.bzxz.net
Nitrogen water (1+1), high purity.
2.8 Copper iron reagent solution (6%). Prepare it before use and filter it before use. 2.9 O-phenanthroline solution (1%): Weigh 1g o-phenanthroline, dissolve it in 100mL warm water and add 2-3 drops of hydrochloric acid (p1.19g/mL), and mix it.
2.10 CAS (0.03%)-TPC (0.2%) solution: Weigh 0.3g chrome azurol S (CAS) and 2g tetradecylpyridinium chloride (TPC) respectively and dissolve them in a small amount of water, then combine them, transfer them into a 1000mL volumetric flask, dilute them with water to the mark, and mix them. 2.11 Acetic acid-sodium acetate buffer solution: Weigh 150g sodium acetate (CH.CONa*3H,0) and dissolve it in 400mL water, add 6mL glacial acetic acid, transfer them into a 1000mL volumetric flask, dilute them with water to the mark, and mix them. The pH of this solution is 5.8. 2.12 2,4-dinitrophenol solution (0.1%): Weigh 0.1g 2,4-dinitrophenol and dissolve it in 100mL ethanol, mix well. 2.13 Shao standard solution:
2.13.1 Weigh 0.1000g pure aluminum (purity ≥ 99.9%), place it in a 250mL polyethylene beaker, add 10mL sodium hydroxide solution (20%), place it in a boiling water bath and heat to dissolve, add 100mL water, acidify with hydrochloric acid (1+1) and add 5mL in excess, transfer to a 1000mL volumetric flask, dilute to the mark with water, and mix well. 1mL of this solution contains 100μg aluminum. 2.13.2 Pipette 10.00 mL of aluminum standard solution (2.13.1) into a 500 mL volumetric flask, add 2 mL of hydrochloric acid (1+1), dilute with water to the scale, and mix. This solution contains 2 g aluminum in 1 mL. 3 Instruments
Spectrophotometer.
4 Sample
The sample should pass through a 0.351 mm sieve.
5 Analysis steps
5.1 Sample quantity
Weigh the sample according to Table 1.
Content range, %
0.003~0.04
0. 040. 10
5.2 Blank test
Carry out a blank test with the sample.
5.3 Determination
GB 8639.3--88
Weigh the sample, name
5.3.1 Place the sample (5.1) in a 200mL beaker, cover with surface blood, add 10mL nitric acid (2.3), wait for the reaction to slow, add 40mL sulfuric acid (2.4), heat until the sample is dissolved, and heat until sulfuric acid smoke appears for 3~4min, remove and cool slightly, slowly add 60~70mL water, heat to dissolve the salts. Remove, cool to room temperature, transfer to a 250mL volumetric flask, dilute to scale with water, and mix well. 5.3.2 Pipette 10.00 mL of test solution (5.3.1) into a 125 mL separatory funnel, add 10 mL of cupferron (2.8) and 15 mL of trifluoromethane (2.1), oscillate immediately for 1 to 2 min, let stand to separate layers, and discard the organic phase; then add 5 mL of cupferron (2.8) and 10 mL of chloroform (2.1), oscillate immediately for 1 to 2 min, let stand to separate layers, and discard the organic phase; add 10 mL of chloroform (2.1), oscillate immediately for 1 to 2 min, let stand to separate layers, and discard the organic phase; then add 5 mL of chloroform (2.1), oscillate for 1 to 2 min, let stand to separate layers, and discard the organic phase. 5.3.3 Transfer the aqueous phase (5.3.2) into a 100 mL beaker, heat at low temperature until sulfuric acid fumes start to appear, remove the beaker, and immediately add 2-3 mL of nitric acid (2.2) along the wall of the beaker, continue heating until sulfuric acid fumes start to appear, remove the beaker, cool slightly, add 10-15 mL of water, heat to dissolve the salts, remove the beaker, and cool to room temperature.
5.3.4 Transfer the test solution (5.3.3) into a 50mL volumetric flask, adjust the volume to about 15~~20mL, add 2~~3 drops of 2,4-dinitrophenol (2.12), adjust the solution to light yellow with ammonia (2.7), then add hydrochloric acid (2.5) until the light yellow color just disappears, add 2mL o-phenanthroline (2.9), 2mL ascorbic acid (2.6) and 5.0mL CAS-TPC solution (2.10), mix well, add 5mL acetic acid-sodium acetate buffer solution (2.11), dilute to the mark with water, mix well, and let stand for 15 minutes. 5.3.5 Transfer part of the solution (5.3.4) into 0.5cm or 1cm colorimetric blood, use the accompanying sample blank as reference, and measure its absorbance at a wavelength of 630nm on a spectrophotometer. Find the corresponding aluminum content from the working curve. 5.4 Drawing of working curve
Pipette 0, 0.50, 1.00, 2.00.3.00, 4.00.5.00mL of aluminum standard solution (2.13.2) and place them in a set of 50mL volumetric flasks respectively. Adjust the volume to about 15-20mL. Then follow the steps in 5.3.4 and transfer part of the solution into a 0.5cm or 1cm colorimetric tube. Take the reagent blank as reference and measure its absorbance at a wavelength of 630nm on a spectrophotometer. Draw the working curve with the aluminum content as the horizontal axis and the absorbance as the vertical axis.
6 Calculation of analysis results
Calculate the percentage of aluminum according to formula (1):
Wherein: m,
GB8639.3—88
Al(%) =- m X 10-
-the amount of aluminum found from the working curve, d;"-test solution fraction ratio;
m.-sample volume, g.
The analysis results are expressed to three decimal places. 7
Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
0. 003~-0. 008 0
>0. 008 0 ~~ 0. 015
>0. 015~0. 040
>0. 040~0. 100
Additional remarks:
This standard was drafted by Jinzhou Ferroalloy Factory. This standard was drafted by Jinzhou Ferroalloy Factory.
The main drafters of this standard are Wu Yuelian and Di Fengtong. 326
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