GB/T 4324.4-1984 Chemical analysis of tungsten - Malachite green photometric method for determination of antimony content
Some standard content:
National Standard of the People's Republic of China bZxz.net
Chemical analysis method of tungsten
Malachite green photometric method for thedetermlnation of anti niony contentUDC669.27:543
.42 :546.86
GB 4324.4—84
This standard is applicable to the determination of antimony content in tungsten powder, tungsten bar, tungsten monoxide, tungstic acid and ammonium tungstate. Determination range: 0.00005～0.005%. This standard complies with GB1467—78 "General Principles and General Provisions of Chemical Analysis Methods for Metallurgical Products". 1 Method Summary
The sample is dissolved in hydrogen peroxide and sodium hydroxide, and the tungsten is complexed with tartaric acid. Under the acidity of about 1.8N sulfuric acid, antimony is separated by precipitation with thioacetamide using (II) as a carrier. In 7N hydrochloric acid, antimony is reduced by stannous chloride and oxidized by sodium nitrite to form antimony chloride anion, which forms a complex with malachite green in a medium of about 2N hydrochloric acid. It is extracted with toluene and its absorbance is measured at a wavelength of 636nm by spectrophotometry.
2 Reagents
Thioacetamide.
Toluene.
Hydrogen peroxide (specific gravity 1.10).
Sulfuric acid (specific gravity 1.84), high-grade purity.
Sulfuric acid (1+1), high-grade purity.
Nitric acid (specific gravity 1.42), high-grade purity.
Hydrochloric acid (specific gravity 1.19), high-grade purity.
Hydrochloric acid (7N): Take 700ml of acid 2.7), add 500ml of water, mix. Perchloric acid (specific gravity 1.67).
Ammonium hydroxide (specific gravity 0.90).
Sodium hydroxide solution (10%), high-grade purity. Tartaric acid solution (50%): Weigh 500g of tartaric acid and dissolve it in 700ml of warm water, dilute it to 1000ml with water, and mix. Mercuric nitrate solution (1%): Weigh 1g of mercuric nitrate (Hg(NOs)2·H2O), place it in a 250ml beaker, add 100ml of water and a few drops of nitric acid (2.6), and dissolve it in warm water. 2.14 Mixed washing solution: Take 10ml of tartaric acid solution (2.12) and 10ml of sulfuric acid (2.5), place them in 80ml of water, mix, add about 0.2g of thioacetamide (2.1), and mix with a spoon. Prepare when needed. Stannous chloride solution (10%): Weigh 2 g of stannous chloride and dissolve it in 20 ml of hydrochloric acid (2.8 ml), mix it with a spoon. Prepare it when needed. 2.15
: Sodium nitrite solution (10%).
Urea solution (50%).
2.18 Malachite green solution (0.2%): Weigh 0.2 g of malachite green, dissolve it in 100 ml of water, filter it and use it. Bromothymol blue solution (0.1%): Weigh 0.1 g of bromothymol blue, place it in a 100 ml beaker, add 3.2 ml of 0.05 N sodium 2.18
hydrogen solution, grind it with a glass rod, add water to dissolve it and dilute it to 100 ml, mix it. National Bureau of Standards 1084-04-12 Issued
1985-03-01 Implementation
GB 4824.4—84
2.20 Antimony standard solution
2.20.1 Weigh 0.0250g of metallic antimony (99.9% or more), place in a 100ml beaker, add 5ml of sulfuric acid (2.4), heat to dissolve, cool, dilute with 20ml of water, add 20ml of sulfuric acid (2.4), cool, transfer to a 250ml volumetric flask, dilute to scale with water, and mix. This solution contains 100μg of antimony in 1ml.
2.20.2 Transfer 5.00ml of antimony standard solution (2.20.1), place in a 250ml volumetric flask, dilute to scale with hydrochloric acid (2.8), mix, this solution contains 2 antimony in 1ml.
3 Sample
The tungsten bar should be crushed and passed through a 120-mesh screen.
Analysis steps
4. 1 Quantity of determination
Three samples should be weighed for determination during analysis. The measured values should be within the allowable difference in the room and the average value should be taken. 4.2 Sample quantity
Weigh the sample quantity according to Table 1.
0,000050.0005
>0.0005 ~0. 001
0.001-0.002
>0.002~0.005
4.3 Empty test
Carry out an empty test with the sample.
4. 4 Determination
Sample amount, g
441, tungsten powder, tungsten rod
4.4.1.1 Place the sample (4.2) in a 200ml beaker, moisten it with 2-3ml water, add 2ml of hydrogen cyanide (2.3) and shake it continuously until the violent reaction subsides, then add 6 m1 hydrogen peroxide (2.3), heat slightly until the sample is completely decomposed (if necessary, add 4-10ml peroxide (2.3) 3, add 1ml sulfuric acid (2.5), 2ml nitric acid (2.6), heat at low temperature and boil for 1-1min, then evaporate until sulfuric acid smoke just appears, rinse the surface blood and the cup wall with a small amount of water, evaporate again until sulfuric acid smoke appears, remove and cool. 4.4.1.2 Add 10-15ml sodium hydroxide solution (2.11)), heat to dissolve the tungstic acid precipitate, add 20ml tartaric acid solution (2.12); boil for 5m, add hot water to dilute the volume to about 12/ml, add 4 drops of bromothymol blue solution (2.19), add ammonium hydroxide (2.10) and until the solution just turns light blue, add 15ml sulfuric acid (2.5) , 2m nitric acid solution (2.13), add hot water to a total volume of about 150ml, add 0.5-0.6g thioacetamide (2.1), stir to dissolve, heat at low temperature and boil for 2min, place at warm temperature for about 1h, filter with medium-speed quantitative filter paper, wash the beaker 3 times with hot mixed washing liquid (2.14), wash the precipitate 5-6 times, transfer the precipitate and the filter paper into the original beaker 1, add 2ml hydrochloric acid (2.7), 15-18ml nitric acid (2.6), 0.5ml pernitrogen acid (2.9), 2ml sulfuric acid (2.4), heat to dissolve the precipitate and destroy the filter paper, evaporate until sulfuric acid smoke appears, rinse the surface and the wall of the cup with a small amount of water, continue to evaporate sulfuric acid smoke and hydrogen wet salt (so that the residual sulfuric acid amount is about 0.1-0.2ml), remove and cool. Add 5ml hydrochloric acid (2.8), place for 5-10min to dissolve the salt.
4.4.1.8 Add 10 drops (about 0.5 ml) of stannous chloride solution (2.15), mix well, let stand for 2 to 5 min, add 20 drops (about 1 ml) of sodium nitrite solution (2.16), mix well, let stand for 2 to 4 min, add 20 drops (about 1 ml) of urea solution (2.17), stir until a large number of bubbles disappear (about 30 s), immediately transfer to a 100 ml separatory funnel, wash the beaker wall with 15 ml of water several times, and then transfer to the separatory funnel. 12
GB 4324. 4-B4
4.4.1.4 Immediately add 10.00ml toluene (2.2), 10 drops (about 0.5ml) malachite green solution <2.18), shake for 1min, let stand to separate, discard the aqueous phase, filter the organic phase through absorbent cotton into 2cm colorimetric III, measure its absorbance at a wavelength of 636nm with toluene (2.2) as reference on a spectrophotometer.
4.4.1.5 Subtract the absorbance of the blank prepared with the sample. Find the corresponding antimony amount from the working curve. 4.4.2 Tungsten trioxide, tungstic acid, ammonium paratungstate Place the sample (4.2) in a 200ml beaker, add 10ml water, 1ml sulfuric acid (2.5), 2ml nitric acid (2.6), heat at low humidity and boil for 5-10min, then evaporate until sulfuric acid smoke just appears, rinse the table and the cup wall with a small amount of water, evaporate again until sulfuric acid smoke appears, remove and cool. The following is carried out according to 4.4.1.2~4.4.1.5. 4.5 Drawing of working curve
Take 0.00, 0.25, 0.50, 1.00, 2.00, 3.00 ml of antimony standard solution (2.20.2) and place them in a group of 100 ml separating funnels respectively. Add hydrochloric acid (2.8) to a total volume of 5 ml. Add 10 drops (about 0.5 ml) of stannous chloride solution (2.15), mix well, let stand for 2 to 5 minutes, add 20 drops (about 1 ml) of sodium nitrite solution (2.16), mix well, let stand for 2 to 4 minutes, add 20 drops (about 1 ml) of urea solution (2.17), stir until a large number of bubbles disappear (about 30 seconds), and add 15 ml of water. The following is according to 4.4.1.4, measure its absorbance, and subtract the absorbance of the reagent blank. Draw a working curve with antimony excess as the horizontal axis and absorbance as the vertical axis. 5 Calculation of analysis results
Calculate the percentage of antimony as follows:
Sb (%)
where m
B is the amount obtained from the working curve, one more sample, name.
The difference in analysis results between experiments should not be greater than the allowable difference listed in Table 2. Table 2
0.00005 ~0.00010
>D.00010~0.00020
>0.00020 ~0. 00040
>0.0004 ~0,0008
> 0.0008 ~ 0.0012
>D.0012~0.0020
>0.0020 ~0.0030
2>0.0030~0,0050
Allowance
Additional Notes:
GB 4324.4—84
This standard was proposed by the Ministry of Metallurgical Industry of the People’s Republic of China. This standard was drafted by Zhuzhou Cemented Carbide Factory. This standard was drafted by the Iron and Steel Research Institute.
The drafters of this standard are Xi Jing and Ling Qi.
From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB895-77 "Chemical Analysis Method for Tungsten" will be invalid. 14
Lotus root 17bzw.cn crispy lotus root simple seed demon Dai Di Honghen travel science 5 fin lake
17izw.com crisp fresh Zi
dry seed iron bee vegetable crane Hong Mei
1 Ying 60 wing
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.