GB 4374.2-1984 Chemical analysis method for magnesium powder and aluminum-magnesium alloy powder 1,10-phenanthroline photometric method for determination of iron content GB4374.2-1984 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical analysis of magnesium powders and aluminium -magnesium aloy powders The 1,10-phenanthroline photometric method for the determination of iron content This standard is applicable to the determination of iron content in magnesium powders and aluminium -magnesium alloy powders. Determination range: 0.010～1.00%. This standard complies with GB1467--78 "General Principles and General Provisions for Chemical Analysis Methods for Metallurgical Products". Method summary
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GB 43T4.2 ---84
The sample is dissolved in hydrochloric acid. In an acidic solution with a pH of 3 to 5, hydroxylamine hydrochloride is used to reduce iron. Iron (II) and 1,10-phenanthroline form a wine-red complex. The absorbance is measured at a wavelength of 510 nm using a spectrophotometer. The test solution contains 1 mg of copper, zinc, silicon, and manganese respectively, which do not interfere with the determination. 2
Reagents and materials
2.1 Hydrochloric acid (1+1)
2.2 Hydroxylamine hydrochloride solution (10%).
2.3 Sodium acetate solution (15%).
2.4 1,10-phenanthroline solution (0.25%). 2.5 Magnesium matrix solution: Weigh 2.000g pure magnesium (99.99%), place in a 200ml beaker, add a small amount of water and slowly add 40ml hydrochloric acid (2.1), after it is completely dissolved, dilute with water to about 80ml, and boil for 5min. Remove, cool to room temperature, transfer to a 100ml volumetric flask, dilute with water to the mark, and mix. This solution contains 20mg magnesium in 1ml. 2.6 Aluminum matrix solution: Weigh 9.000g blue aluminum chloride (AlC13·6H,O), place in a 200ml beaker, add 80ml water, after it is completely dissolved, filter into a 100ml volumetric flask, dilute with water to the mark, and mix. This solution contains 10mg aluminum in 1ml. 2.7 Iron standard stock solution: Weigh 0.1000g pure iron (99.9% or more), place in a 200ml beaker, add 50ml water, 25ml hydrochloric acid (2.1) and 1ml nitric acid (specific gravity 1.42), heat to dissolve, boil and drive off nitrogen oxides. Cool, transfer to a 1000ml volumetric flask, dilute to scale with water, and mix. This solution contains 0.1mg iron per ml. 2.8 Iron standard solution: Transfer 100.0ml iron standard stock solution (2.7), place in a 500ml volumetric flask, dilute to scale with water, and mix. This solution contains 20μg iron per ml.
2.9 Congo red test paper (cut into small pieces without burrs). 3 Instruments
Spectrophotometer.
Analysis steps
4.1 Determination quantity
Measure two samples in parallel and take the average value. Issued by the National Bureau of Standards on April 30, 1984
Implemented on April 1, 1985
4.2 Sample quantity
Weigh the sample according to Table 1.
Iron content,
0.010~0.10
>0.10 ~1.00
4.3 Blank test
GB 4374.2 --84
Sample content,
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Weigh the sample (4.2) according to Table 1 and place it in a 200ml beaker. The following shall be carried out according to 4.4.2, 4.4.3 (without adding 1,10 nitrogen non-solution), and 4.4.4.
4.4 Determination
4.4.1 Place the sample (4.2) in a 200ml beaker. 4.4.2 Add a small amount of water and 4 ml of hydrochloric acid (2.1). After the sample is completely dissolved, dilute it with water to about 40 ml, boil for 5 minutes, remove it, cool it to room temperature, and transfer it to a 100 ml volumetric flask. 4.4.3 Add 4 ml of hydroxylamine hydrochloride solution (2.2) and 5 ml of 1.10-phenanthroline solution (2.4), and put it into a small piece of Congo red test paper (2.9).
4.4.4 Use sodium acetate solution (2.3) to adjust the solution to the star red color of the Congo red test paper and add 5 ml in excess, dilute it with water to the scale, and mix it. Let it stand for 10 minutes.
4.4.5 Transfer part of the solution (4.4.4) to a 2 cm colorimetric blood, use the empty test solution (4.3) as a reference, and measure its absorbance at a spectrophotometric wavelength of 510 nm. Find the corresponding iron content from the death curve. 4.5 Drawing of working curve
4.5.1 Drawing of working curve of iron in magnesium powder4.5.1.1 According to the sample volume (4.2), transfer an appropriate amount of magnesium matrix solution (2.5) (the amount of magnesium should be equivalent to that contained in the sample volume), place it in a 100ml volumetric flask, and add 0.00, 1.00, 2.00, 3.00, 4.00, and 5.00ml of iron standard solution (2.8) respectively. The following is carried out according to 4.4.3~4.4.4.
4.5.1.2 Transfer part of the solution (4.5.1.1) into a 2cm colorimetric H, use the compensation solution (the one without iron standard solution in 4.5.1.1) as a reference, and measure its absorbance at a wavelength of 510nm on a spectrophotometer. Draw a curve with the amount of iron as the horizontal axis and the absorbance as the vertical axis! . 4.5.2 Drawing of working curve of iron in aluminum-magnesium alloy powder 4.5.2.1 According to the sample volume (4.2), transfer appropriate amount (the amount of aluminum and magnesium should be equivalent to that contained in the sample volume) of aluminum matrix solution (2.6) and magnesium matrix solution (2.5), place them in a 100ml volumetric flask, and add 0.00, 1.00, 2.00, 3.00, 4.00, 5.00ml of iron standard solution (2.8) respectively. The following is carried out according to 4.4.3 to 4.4.4. 4.5.2.2 Transfer part of the solution (4.5.2.1) into 2cm colorimetric III, use the compensation solution (4.5.2.11 without adding iron standard solution) as reference, and measure its absorbance at a wavelength of 510nm on a spectrophotometer. Draw a curve with the amount of iron as the horizontal axis and the absorbance as the vertical axis. 5
Calculation of analysis results
Calculate the percentage of iron as follows:
Fe (%) =
Where: m, the amount of iron found from the curve above, gm-sample weight, g.
Allowable difference
GB.4374.2--84
The difference in analysis results between laboratories should not be large" Table 2 lists the allowable difference. Table 2
0.010~0.050
0.050~0.150
0.15~0.50
>0.50 ~1.00
Additional remarks:
This standard is proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard is drafted by the Northeast Light Alloy Processing Plant. This standard is drafted by the Northeast Light Alloy Processing Plant and the Northwest Aluminum Processing Plant. The main drafters of this standard are Guan Wenxiang and Wang Yejun. 150
Allowable difference
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