YB/T 178.5-2000 Chemical analysis methods for silicon-aluminium alloys and silicon-barium-aluminium alloys - Determination of phosphorus content by phosphomolybdenum blue spectrophotometry

This standard specifies the determination of phosphorus content by phosphomolybdenum blue spectrophotometry. This standard is applicable to the determination of phosphorus content in silicon aluminum alloys and silicon-barium aluminum alloys. Determination range: 0.010% (m/m) ~ 0.050% (m/m). YB/T 178.5-2000 Chemical analysis method for silicon aluminum alloys and silicon-barium aluminum alloys Determination of phosphorus content by phosphomolybdenum blue spectrophotometry YB/T178.5-2000 Standard download decompression password: www.bzxz.net

YB/T 178. 5--2000
Silicon aluminum alloy and silicon barium aluminum alloy are used as efficient deoxidation, desulfurization or grain refinement additives. This standard is formulated to match the product standards.
During the formulation of this standard, the phosphorus molybdenum blue spectrophotometry was used to conduct comprehensive condition tests, focusing on the color development acidity of phosphorus, the wavelength of measurement, and the interference elements and their elimination. YB/T178 includes the following parts under the general title of "Chemical Analysis Methods for Silicon Aluminum Alloys and Silicon Barium Aluminum Alloys", and this standard is Part 5.
Determination of silicon content by weight method of perchloric acid dehydration
Determination of barium content by weight method of barium sulfate
Determination of aluminum content by EDTA titration
Determination of manganese content by sodium periodate spectrophotometry Determination of phosphorus content by phosphorus button blue spectrophotometry
Determination of carbon content by infrared absorption
7) Determination of sulfur content by infrared absorption
This standard is proposed and managed by the Metallurgical Information Standards Research Institute. This standard is drafted by Shanghai Baosteel Group Corporation. The main drafters of this standard are: Liu Xiaoping, Chen Yuyuan, Zhu Yuefang, and Wang Ronggang. 671
1 Scope
Standard of Ferrous Metallurgy Industry of the People's Republic of China Method for Chemical Analysis of Silicon-Aluminiumalloy and Silicon-Barium-Aluminium Alloy The molybdeum blue spectrophotometric methodfor the determination of phosphorus content
Method for chemical analysis of silicon-aluminiumalloy and silicon-barium-aluminium alloyThe molybdeum blue spectrophotometric methodfor the determination of phosphorus contentThis standard specifies the determination of phosphorus content by molybdenum blue spectrophotometry. This standard is applicable to the determination of phosphorus content in silicon-aluminium alloy and silicon-barium-aluminium alloy. Determination range: 0.010% (m/m)~0.050% (m/m). 2 Referenced standards
YB/T178.5--2000
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. The versions shown are valid at the time of publication of this standard. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T4010—1994 Collection and preparation of samples for chemical analysis of ferroalloys 3 Method Summary
The sample is dissolved in nitric acid and hydrofluoric acid, treated with perchloric acid fuming to oxidize phosphorus to orthophosphoric acid, and in a medium of about 0.5 mol/L hydrochloric acid, hydroxylamine hydrochloride and ascorbic acid are used as reducing agents to reduce the generated phosphomolybdic heteropoly acid to phosphomolybdic blue, and the absorbance is measured at a wavelength of 825 nm on a spectrophotometer.
4 Reagents and materials
In the analysis, unless otherwise specified, only recognized analytical reagents and distilled water or water of equivalent purity are used. 4.1 Nitric acid (p=1.42g/ml).
4.2 Hydrofluoric acid (p=1.15g/mL).
4.3 Perchloric acid (p=1.67g/mL).
4.4 Hydrochloric acid (1+4): dilute with hydrochloric acid (o=1.19g/mL) with water. 4.5 Ammonium molybdate solution (15g/L).
4.6 Hydroxylamine hydrochloride solution (40g/1.).
4.7 Ascorbic acid solution (20g/L): prepare freshly before use. 4.8 Phosphorus standard solutionwww.bzxz.net
4.8.1 Phosphorus standard solution (100μg/ml.): weigh 0.4394g of potassium dihydrogen phosphate (reference reagent) that has been dried at 105℃ for 2h and cooled to room temperature in a 200mL beaker, add 50mL of water to dissolve, transfer to a 1000ml volumetric flask, dilute to scale with water, and mix well. This solution contains 100μg of phosphorus in 1.00mL. Approved by the State Metallurgical Industry Bureau on July 26, 2000, 672
Implemented on December 1, 2000
, 4.8.2 Phosphorus standard solution (4μg/ml.) YB/T 178.5—2000
Pipette 20.00mL of phosphorus standard solution (4.9.1) into a 500mL volumetric flask, dilute to the mark with water, and mix. This solution contains 4μg phosphorus in 1.00mL.
5 Instruments and equipment
In the analysis, only common laboratory instruments and equipment are used. 6 Sample preparation
Sample preparation shall be carried out in accordance with the provisions of GB/T4010. The sample shall pass through a 0.125mm sieve and be stored in a sealed dry container for no more than 6 months.
7 Analysis steps
Safety instructions: Usually in the presence of ammonia, nitrogen oxides or organic matter, the emission of perchloric acid fumes may cause an explosion. Hydrofluoric acid can severely burn the human body, and safety measures should be taken when using it. 7.1 Sample quantity
Weigh 0.20g of sample, accurate to 0.0001g. 7.2 Blank test
Perform a blank test with the sample.
7.3 Determination
7.3.1 Place the sample (7.1) in a 200mL polytetrafluoroethylene beaker, add 10mL nitric acid (4.1), slowly add 5ml of hydrofluoric acid (4.2), heat at low temperature on an electric furnace until the sample is completely dissolved, then add 10mL of perchloric acid (4.3), and continue heating until it smokes and is nearly dry. Note: If the sample contains arsenic, add 2 mL of hydrobromic acid (p=1.49 g/mL) and 5 mL of hydrochloric acid (p=1.19 g/ml) before adding perfluoric acid. 7.3.2 Remove, cool, add 20 mL of water, heat until the salts are dissolved, cool to room temperature, transfer to a 100 mL volumetric flask, dilute to scale with water, and mix (if there is precipitation, dry filter). 7.3.3 Take 20.00 mL of solution (7.3.2) in a 50 mL volumetric flask, add 10 mL of hydrochloric acid (4.4), add 5 mL of ammonium molybdate solution (4.5), mix well, add 4 mL of hydroxylamine hydrochloride solution (4.6), 4 mL of ascorbic acid solution (4.7), mix well, place in a boiling water bath and heat for 5 min, cool to room temperature with running water, dilute to scale with water, and mix well. 7.3.4 Measurement
Use the blank test solution as a reference, use 2 cm absorbent tube, and measure the absorbance at a wavelength of 825 nm on a spectrophotometer. Find the corresponding phosphorus content on the calibration curve.
7.4 Drawing of calibration curve
Pipette 0, 1.00, 2.00, 3.00, 4.00, 5.00, 6.00, 7.00 ml of phosphorus standard solution (4.8.2) into 8 50 ml volumetric flasks, add water to 20 ml, and operate according to 7.3.3. Use the standard solution without phosphorus as a reference, and measure the absorbance according to 7.3.4. Draw a calibration curve with phosphorus content as the horizontal axis and absorbance as the vertical axis. 8 Calculation of analysis results
Calculate the mass percentage of phosphorus P (%) according to formula (1) =
Wherein: m.—phosphorus content found from the calibration curve, g; m—sample volume, g
V,—volume of the test solution taken, mL;
-total volume of the test solution, mL.
Analysis results should be expressed to three decimal places. 9 Allowable difference
YB/T178.5--2000
The difference between two independent analysis results should not be greater than the allowable difference listed in Table 1. Table 1
Phosphorus content
0. 010~0.030
≥0.030～0.050
Test report
The test report should include the following contents:
a) Identification of the test material, laboratory and analysis date; b) The degree of compliance with the provisions of this standard;
c) Analysis results and their expression;
d) Abnormal phenomena observed during the determination;
e) Operations that may affect the analysis results but are not included in this standard, or optional operations. 674
Allowance
%(m/m)
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