GB/T 4324.20-1984 Chemical analysis of tungsten - Tantalum reagent photometric method for the determination of vanadium content
Some standard content:
National Standard of the People's Republic of China
Chemical analysis method of tungsten
Determination of molybdenum content by photometric method with molybdenum reagent
Methods for chemical analysis of tungstenThe N-benzoyl-N-phenylhydroxylaminephotometric method forthedeterminationof vanadiun content
UDC 669.27: 543
-42:546.881
GB4324.20--84
This standard is applicable to the determination of vanadium content in pigeon powder, tungsten bar, tungsten trioxide, tungstic acid and ammonium pigeon acid. Determination range: 0.00030-0.040%. This standard complies with GB1467-78 "General Principles and General Term Standards for Chemical Analysis Methods of Metallurgical Products". 1 Method Summary
The sample is dissolved in sulfuric acid-ammonium sulfate or sodium hydroxide, and the main component and trace amount of vanadium and vanadium are complexed with sodium tartrate and a small amount of phosphoric acid. In the presence of acetate buffer (nH4.5-5.0), a small amount of tin (V) is used as a carrier, and the reagent: "chloromethane is used to extract and separate trace amounts of vanadium in pigeons. In a 1.5N sulfuric acid medium, vanadium (V) and the reagent form an orange-yellow complex, which is extracted with a trichloroethane-ethanol mixed reagent cup and its absorbance is measured.
2 Reagents
2.1 Sodium hydroxide.
Sulfuric acid (specific gravity 1.84).
Sulfuric acid (1+1).
Hydrochloric acid (specific gravity 1.19). bzxZ.net
2.5 Acid (1 +1).
Nitric acid (specific gravity 1.42).
Perchloric acid (specific gravity 1.67).
Phosphoric acid (specific gravity 1.70)
Ammonium hydroxide (specific gravity 0.90).
Ammonium hydroxide (1+1).
Chloroform.
Sodium hydroxide solution (10%).
Sodium hydroxide solution (20%)
Sulfuric acid-ammonium sulfate mixture: press 2 Ni sulfuric acid (specific gravity 1.84), 1 ammonium sulfate ratio mix, set aside. Sodium tartrate solution (20%).
Potassium tartrate solution (0.1%).
Urea solution (20%).
Sodium nitrite solution (0.2%).
Sodium ethyl dithiocarbamate (copper reagent) solution (4%). Prepare when needed. N-benzoyl N-phenylhydroxylamine (palladium reagent) solution (0.2%): weigh 0.5g of molybdenum reagent and dissolve it in 200ml of chloroform and 50ml of ethanol, mix and put it in a brown bottle. National Bureau of Standards 1984: 04-12 Issued
1985-03-01 Implementation
GB 4324.20—84
2.21 Acetic acid buffer solution (pl14.1): Take 11.8ml acetic acid, add 4.2g anhydrous sodium acetate, dissolve with a small amount of water, transfer to a 500ml volumetric flask, dilute to scale with water, and mix. 2.22 Pot (TV) solution: Weigh 0.2962g tin chloride (SnCl·5H,0), dissolve with hydrochloric acid (1+9). Transfer to a 200ml volumetric flask, dilute to scale with acid (1+9), and mix. 1ml of this solution will be 500μ tin (IV). 2.23 Phenol solution (0.05%): Prepare with alcohol (1+4). 2.24 Standard solution
2.24.1 Take), 1785g vanadium pentoxide (reference reagent), place in a 100ml cup, add, 4 2 m1 sodium hydroxide solution (2.13), completely dissolve in the heating jacket, acidify with 10ml sulfuric acid (1+3), add a few drops of nitric acid (2.6), evaporate all the sulfuric acid fumes, take a cup and cool it slightly, rinse the cup and the wall with a little water, emit sulfuric acid fumes again, drive out all the nitric acid, cool it, transfer it to a 200ml volumetric flask, dilute it with water to the mark and mix it. This solution contains 5g per ml.
2.24.2 Transfer 20ml of standard bath solution (2.24.1), place it in a 200ml volumetric flask, dilute it with water to the mark, mix it, and this solution contains 50μg vanadium
2.24.3 Transfer 20.00ml of vanadium standard solution (2.24.2), place it in a 100ml volumetric flask: 1, dilute it with water to the mark, mix it. This solution contains 10 per ml,
3 The sample
strips should be crushed and passed through a 120! sieve.
4 Analysis steps
4. 1 Determination quantity
Three samples should be weighed for determination during analysis. The determination value should be within the allowable difference in the room, and the average value should be taken. 4.2 Sample quantity
Weigh 1000~1.000g sample
4.3 White test
Carry out micro-vacuum test with the sample.
4.4 Determination
4.4.1 Crane powder, woven strips
4.4.1.1 Place the sample (4.2) in a 100ml beaker. Add 10~12ml sulfuric acid and ammonium sulfate mixed solution (2.14) and heat and dissolve it on a high-temperature electric furnace. When the test solution is clear (when taking the sample, it often turns into an acid state when heated and dissolved at high temperature, and a yellow precipitate is observed. There is no powder in the package, and it is ready), evaporate the sulfuric acid! When the temperature is not too high, cool it down slightly, add sodium chlorite solution (2.12) [When weighing 1.0g of sample, add 10ml sodium oxychloride solution (2.13), heat until it is partially dissolved, add 15ml sodium chlorite solution (2.5), heat on the hot plate until the gold is dissolved [If there is still insoluble matter, add appropriate amount of sodium chlorite solution (2.1) until the solution is positive). Fill with 14 drops of phosphoric acid (2.8), cool it down slightly. 4. 4.1.2 Add 1 ml tin (IV) Solution (2,92), transfer to a 125mD shaped separatory funnel, add water to make the volume about 40ml, add 2-3 drops of phenol violet solution (2.), at this time the test solution is purple [if it turns to yellow, it means that the amount of alkali is insufficient, and ammonium hydroxide (2.9) can be added to adjust the purple color, add 1 drop of loading acid (2.5) until the test solution turns slightly purple, then add 1 drop, add 10ml acetate buffer solution (2.21), at this time the volume is about ml (pH 1.5), add 3 ml copper test solution (2.19), mix, wait for a while (about 4-5 minutes). 10 ml of system (2.11), stir for 1.5 minutes, let stand for stratification, put the organic phase into the original beaker. Add 2 ml copper test solution (2.19) to the aqueous phase, add 1 ml trichloroethane (2.11), shake for 1 minute, put the organic phase into the original beaker. Finally, add 5 ml of methyl chloride (2.11) + water, shake for 1 minute, put the organic phase into the original beaker, and discard the aqueous phase. 4.4.1.3 Steam 1 cup of organic phase on a hot plate In the next step, add 3ml nitric acid (2.6) and 1ml perchloric acid (2.7), heat to fully oxidize and destroy organic matter, evaporate the perchloric acid fumes until ten percent, remove, cool slightly, add 1ml sulfuric acid (2.3) to decompose the cyclohexane, rinse the surface and cup with a little water, evaporate with solitary heat, remove the sulfuric acid fumes for a while, remove, cool slightly, rinse with a little water, evaporate until the sulfuric acid fumes are gone. After a while, add 2.00ml sulfuric acid (2.3) and heat slightly to dissolve the contents in the cup. Transfer with water to a 125ml pear-shaped separatory funnel and make the final volume GB 4824.2084
The volume is 20ml.
4.4.1.4 Add potassium permanganate solution (2.16) dropwise until the test solution turns light red and does not fade, add 1ml urea solution (2.17), add sodium nitrite solution (2.18) dropwise until the light purple red just fades, add 1 more drop, add 1ml phosphoric acid (2.8) (add both reagents briefly and mix thoroughly), add 10.00ml sodium chloride solution (2.20), shake vigorously for 2min, let stand and separate, and the organic phase is separated by deionization. Move the cotton wool into the 2cm colorimetric medium.
4.4.1.5 Take the blank sample made with the sample as reference, measure its absorbance at a wavelength of 44nm on the spectrophotometer, and find the corresponding vanadium content on the above curve.
4.4.2 Tungsten trioxide, tungstic acid, and ammonium tungstate Place the sample (4.2) in a 100ml beaker, add 5ml sodium hydroxide solution (2.12), 5ml water, heat to dissolve, add 15ml sodium tartrate solution (2.15), 4 drops of phosphoric acid (2.8), and cool slightly. The following is carried out according to 4.4.1.2-4.4.1.5. 4.5 Drawing of working curve
Pipette 0.00, 0.25, 0.50, 1.00, 2.00, 4.10, 6.00 ml of vanadium standard solution (2.24.3) and place them in a set of 125 ml pear-shaped separatory funnels. Add 2.00 ml of sulfuric acid (2.3) and water to make the volume 20 ml. Follow 4.4.1.4. Take the empty reagent as reference and measure its absorbance. Take the vanadium content as the horizontal coordinate and the light intensity as the vertical coordinate to make a working curve. 5. Calculation of analysis results
Calculate the vanadium content according to the following formula:
Where: mr
allowable coupon
the vanadium content found from the working curve,
sample volume, 8.
The difference between the experimental results and the analytical results should not be greater than the allowable difference listed in the table. %
0.0005-0 1015
20.6015~0.0030
:-0. 0030 - 0. 0070
*0.007-0,016
-0.015-0.h
Additional remarks:
This standard was proposed by the Ministry of Metallurgy of the People's Republic of China. This standard was drafted by Zhuzhou Cemented Carbide! Fushan. This standard was drafted by the Iron and Steel Research Institute.
The main drafters of this standard are Zhang Yueluo and Sun Guangui. Since the implementation of this standard, the original metallurgical industry standard YB895-77 "Calcium Chemical Analysis Method" will be invalid.
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