GB/T 4324.22-1984 Chemical analysis of tungsten - Formaldehyde oxime spectrophotometric method for determination of manganese content

GB/T 4324.22-1984 Chemical analysis method for tungsten - Formaldehyde oxime spectrophotometric method for determination of manganese content GB/T4324.22-1984 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Melts for chemical analysis of tungstenThe formaldoxime photometric methodfor maaganese content
UDC669.271543
.42:546.711
GB 4324.22—84
This standard is applicable to the determination of manganese content in pigeon powder, tungsten bars, tungsten trioxide, pigeon acid and ammonium paratungstate. Determination range: 0.0005~0.020%. This standard complies with GB1467-78 "General provisions and general rules of chemical analysis methods for metallurgical products". 1. Method summary
The sample is dissolved with sodium hydroxide and hydrogen peroxide, citric acid is used as the main component, hydrochloric acid is used for leaching, and methyl isocyanate complex is extracted to separate it. The remaining impurities are masked with potassium cyanide, and the solution pI is controlled at 110-11. The color is developed with aldehyde hydrochloric acid and the absorbance is measured.
Reagents and materials Www.bzxZ.net
Hydrochloric acid (specific gravity 1.19), high purity.
Hydrochloric acid (3+2), high purity.
Hydrochloric acid (1+1), high purity.
Ammonium hydroxide (specific gravity 0.90), high purity.
Ammonium hydroxide (specific gravity 1), high purity.
Peroxide (specific gravity 1.10).
Non-isocyanate.
Sodium thiocyanate solution (15%), high purity. Citric acid solution (70%).
Potassium thiocyanate solution (50%).
Potassium cyanide solution (4%).
Formaldehyde hydrochloride solution
Formaldehyde hydrochloride solution (8%): ​​
Weigh 7.0g hydroxylamine hydrochloride and dissolve it in water, add 8g formaldehyde hydrochloride, mix, add 8ml hydrochloric acid (2.1), dilute with water to 100ml, and mix.
2.12.2 Formaldehyde hydrochloride solution (2%): Take 2ml formaldehyde hydrochloride solution (2.12.1), add 2ml ammonium hydroxide solution (2.4), dilute with water to 8nl, and mix. Prepare when needed.
2.13 Wide range pH test paper (pH1~14).
2.14 Single distilled water or ion exchange water. 2.15 Manganese standard solution
2.15.1 Take 0.4000g of manganese (99.99%) which has been previously washed with phosphorus sulfuric acid, rinsed with ethyl alcohol and then dried, and put it in a 250ml beaker. Add 50ml sulfuric acid (14%), heat to dissolve, dilute with water, and add 12ml sulfuric acid (specific gravity 1.84), cool, transfer to a 1000ml volumetric flask, dilute to the mark with water, and mix. This solution contains 400μg manganese in 1ml. 2.15.2 Take 10.00ml of manganese standard solution (2.15.1), place it in a 1000nl volumetric flask, dilute with water to about 500ml, add 1Uml sulfuric acid (ratio 1.84), cool, dilute with water to the mark, and mix. This solution contains 4μg manganese in 1ml. 3 Sample
3.1 Tungsten bars should be crushed and pass through a 120 mesh. 3.2 Factory pigeon bars, tin powder, first oxidize in an electric furnace for 30min and then move to a high-temperature furnace and burn at 750 for 30min to make its hydrogen bloom into calcium trioxide. 4 Analysis steps
Measurement quantity
During the analysis, two samples should be weighed for measurement. The measured value should be within the indoor allowable difference and the half mean value should be taken. 4.2 Sample quantity
Weigh 0.10001.000g of sample.
1.3 Blank test
Carry out a blank test with the sample.
4.4 Determination
4.4.1 Place the sample (4.2) in a 150ml polytetrafluoroethylene beaker, add 3ml sodium hydroxide solution (2.8), place it on a low-temperature electric stove with an asbestos board for heating, and add 5 drops of hydrogen peroxide (2.6) after the sample is basically dissolved. Continue heating until it is completely dissolved and evaporated. Drive away all the hydrogen peroxide and cool.
4.4.2 Rinse with a small amount of water, add 7ml citric acid solution (2.9), mix, heat on a low-temperature electric stove until it is slightly boiling, remove and cool to room temperature.||t t||4.4.3 Add 1ml hydrochloric acid (2.2) dropwise, mix well, boil for a while in a low-temperature electric furnace, remove and cool. 4.4.4 Transfer to a 60ml separatory funnel, add 1ml potassium thiocyanate solution (2.10), stir, add 10ml methyl isocyanate (2.7), shake for 2min, let stand to separate, transfer the aqueous phase to another 60ml separatory funnel, add 4 drops of hydrochloric acid (2.2), mix well, then shake with 10ml 1-hydroxyethyl ether (2.7) for 2min, let stand to separate, transfer the aqueous phase to a 235ml volumetric flask. The temperature during extraction should not be lower than 20℃. 4.4.5 Add 8-10 ml ammonium hydroxide (2.4) to adjust the solution pH to 10-11, add 2 ml potassium cyanide solution (2.11), mix well, add 1 ml formaldehyde hydrochloride solution (2.12.2), dilute to scale with water, mix well, place in a 60-70℃ water bath for 20 minutes to develop color, and cool.
Transfer part of the solution to a 3 cm colorimetric tube, use water as a reference, and measure its absorbance at a wavelength of 455 nm on a spectrophotometer. 4.4. Subtract the absorbance of the blank made with the sample in sequence. Find the corresponding manganese content from the working curve. 4.5 Drawing of working curve
Take 0.00, 1.00, 2.00, 3.00, 4.00, 5.00 ml of manganese standard solution (2.15.2) and put them into 25 ml volumetric bottles respectively. Add ammonium hydroxide (2.5) dropwise to make the solution pH 10-11 (check with wide pH test paper), add 2 ml of potassium cyanide solution (211), mix well, add 1 m formaldehyde cyanate solution (2.12.2), dilute to scale with water, mix well, place in a 60-70℃ water bath for 20 minutes to develop color, cool, and proceed as in 4.4.6. Subtract the absorbance of the reagent blank. Draw the working curve with the manganese content as the horizontal axis and the absorbance as the vertical axis.
5 Sieve of analysis results
Calculate the percentage of manganese in tungsten dioxide, tungstic acid and ammonium paratungstate according to formula (1): 5.1
Formula fm
-The amount of manganese found from the working curve, g, sample weight, K.
5.2 Calculate the percentage of manganese in tungsten powder and tungsten bar according to formula (2): 74
Wu Zhong: m
Allowable difference
GB 4324.22-84
Mn(%) =
-The amount of manganese found from the working curve, g: Sample weight: g
Conversion factor for converting tungsten trioxide to tungsten. m ×0.7930
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table.
0.00050-.00150
0.06150--0.00250
>0.0025~0.0050
20,0050~0.0080
≥0,0080~0.0200
Additional remarks:
This standard is proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard is drafted by Zhuzhou Cemented Carbide Factory. This standard is drafted by South Bureau Cemented Carbide Factory
Allowance
The main drafters of this standard are Sun Jingyong, Zheng Xiuyi and Shu Xiaodan. From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB895-77 "Chemical Analysis Method of Tungsten" will be invalidated. Lotus root 17bzw.cn crisp lotus root simple seed demon Dai Yan red mark travel science 5 fin lake || tt || 17izw.com crisp fresh essence || tt || dry seed fertile bee vegetable crane boom charm || tt || 1 Ying 60 wing
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