GB/T 4699.3-1984 Chemical analysis methods for silicon-chromium alloys - Molybdenum blue photometric method for determination of phosphorus content

GB/T 4699.3-1984 Chemical analysis methods for silicon-chromium alloys - Determination of phosphorus content by molybdenum blue photometric method GB/T4699.3-1984 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical analysis of siticochromiumThe molybdenum blue photumetric methodfor the determination of phosphorus contentThis standard is suitable for the determination of phosphorus in Taiwan alloys. The determination range is: 0.010~0.060UDC 669.782.5' 26
543.4 : 546
GB 4699.3--84Www.bzxZ.net
This standard complies with the General Principles and General Provisions of Chemical Method Standards for Metallurgical Products (H146-78). Method Summary
The sample is dissolved in nitric acid and oxygen, and the hydrogen peroxide is oxidized to form phosphorus aldehyde. The odor is removed by nitrogenous acid and sodium chloride, and sodium sulfate is used to remove the odor. Ammonium ions and sodium sulfate are added to react. The phosphorus absorption is measured with a decimeter photometer. Sodium chloride: 2.2 High density ammonium hydroxide (specific gravity 1.67) 2.3 Hydrogen hydride (specific gravity 1.15) 2.4 Nitric acid (specific gravity 1.42) 2.5 Nitric acid (specific gravity 1.19) 2.6 Ammonium sulfate solution (0%) 2.7 Developer solution 2.7.1 Weigh 20g ammonium hydroxide (NI2Mo244H2O3) and dissolve it in 100ml warm water and 700ml sulfuric acid (1 +1). Dilute to 1000 ml in water, about 2.7.2 Weigh 1.55 ml of the collected water, dilute to 1000 ml, and mix. 2.7.3 Method: 25.09 ml of the tube liquid (3.7.1), 10 ml of hydrazine sulfate liquid (2.7.2) and 65 ml of water, mix well, and take 25 ml of this solution each time.
2.8 Standard solution: weigh n.1394 g of micro-boil at 11°C until the volume is reached and store : Take 1% potassium hydrogen phosphate (KH2PO4) from the mold, transfer it into 1000ml of the container and dilute it with water until it is mixed. This solution contains 0.1mg phosphorus in 1ml. 3
The sample is placed on a 0.125mm tube.
Analysis steps
4.1 The sample is taken and the test sample is 5000% tested. The standard is relatively complete. National Bureau of Standards 1984-10 04 Issued
1985-09-01 Implementation
4.2 Air force test
Carry out air force test with the sample.
GB 4699.3-84
4.3.1 Place the sample (4.1) in 100ml platinum, add 20ml nitric acid (2.4), place it in a cold water bath, and add 5-10ml hydrofluoric acid (2.3) drop by drop to decompose. 4.3.2 Add 15ml perfluoric acid (2.2) and heat to evaporate until smoke appears. When the liquid turns red, wash the solution with running water and transfer it to a 300ml beaker. Heat to evaporate until white smoke appears. Keep heating for about 10 minutes while the vapor of perchloric acid (2.2) refluxes along the wall of the beaker. 3.3 While heating the solution, add 5ml hydrochloric acid (2.5) to volatilize the chromium. Continue heating to remove the chromium oxide. Add 5ml hydrochloric acid (2.5) repeatedly. Then, add about 1g sodium oxide (2.1) while heating to volatilize the chromium. Repeat the operation of adding sodium nitride until the chromium chloride color release hydrogen no longer appears. Continue to produce white smoke to remove chlorine. Note: When removing chromium, in order to prevent the addition of small salts, the residual clearing agent should be completely decomposed when the chromium is removed. 4.3.4 After the natural cooling period, add 40ml of water to dissolve the soluble salts, filter the filter paper into a 250ml volumetric flask: 1: add a small amount of pulp, wash the filter paper 4 to 5 times with warm water, cool to room temperature with running water to the water release rate scale, and mix with a spoon. 4.3.5 Take 25.00ml of solution (4.3.4) and transfer it to a 10ml flask, add 10ml of sodium bisulfite solution (2.6), heat in a boiling water bath until it dissolves, immediately add 25ml of developer solution (2.7.3), heat in a boiling water bath for 15min, cool to room temperature in running water, dilute with water to the mark, mix 4.3.6 Transfer part of the colorimetric solution (4.3.5) to a suitable half of the colorimetric medium, compare it with the reference in the test space, measure the photometric value at 825nm: draw a line, and check the phase of the comparison. Drawing of working curve
Pipette 0, 1.00, 2.00, 3.00, 4.00, 5.00 ml of phosphorus standard bath solution (2.8), place in 100 ml beakers, add 5 ml of high acid (2.2) to each beaker, heat and then produce high light intensity of 1:1, and proceed as per 1.3.4~4.3.5, taking reagent blank as reference, and measure absorbance at the same ratio and wavelength as in 4.3.6. Draw a curve with phosphorus content as the horizontal axis and absorbance as the vertical axis. 6
Calculation of analysis results
Calculate the percentage of phosphorus by the following formula:
Where: m--phosphorus content obtained from the working curve, mgmp-sample amount, g
-test wavelength ratio,
Analysis results are expressed to three decimal places. Allowable error
tnp*7 ×1000
The difference between the analysis results of the experimental cases should not be greater than the allowable error listed in the following table.
-0.0: 0--0.040
0.040 ~ 0.066.
GB 4699.3 --a4
Additional remarks:
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. Shanghai Ferroalloy was responsible for drafting. From the implementation of this standard, the original Ministry of Metallurgical Industry Standard YH577-65 "Chemical Analysis Method of Silicon Chromium Alloy" will be invalidated.
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