This standard specifies the determination method of selenium content in antimony trioxide. This standard is applicable to the determination of selenium content in antimony trioxide. Determination range: 0.000 50% to 0.040%. GB/T 3254.6-1998 Chemical analysis method for antimony trioxide Determination of selenium content GB/T3254.6-1998 Standard download decompression password: www.bzxz.net

1 Scope
National Standard of the People's Republic of China
Chemical analysis method of antimony trioxide
Determination of selenium content
Antimony trioxide Determination of selenium contentThis standard specifies the method for determining the selenium content in antimony trioxide. GB/T 3254. 6--1998
This standard is applicable to the determination of selenium content in antimony trioxide. Determination range: 0.00050%~0.040%. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB1.4--88 Guidelines for Standardization Work Provisions for the Preparation of Chemical Analysis Methods GB1467-78 General Principles and General Provisions for Chemical Analysis Methods for Metallurgical Products GB7729---87 General Principles for Spectrophotometric Methods for Chemical Analysis of Metallurgical Products 3 Method Summary
The sample is decomposed with hydrochloric acid and ammonium persulfate, and arsenic is added to remove excess ammonium persulfate. The main component antimony is masked with ammonium citrate-oxalic acid-triethanolamine, and NazEDTA is used to eliminate the interference of impurity elements such as lead, copper, and iron. The colored complex formed by selenium (V) and selenium reagent is extracted with methanol, and its absorbance is measured at a wavelength of 430nm on a spectrophotometer. 4 Reagents
4.1 Toluene.
4.2 Hydrochloric acid (pl.19g/mL).
4.3 Nitric acid (pl.42g/ml).
Ammonia water (p0.90g/mL).
Hydrochloric acid (1+1).
Ammonia water (1+4).
Ammonium persulfate solution (200g/L).
3Silver nitrate solution (10g/L).
4.9Arsenic solution (10g/L): Weigh 1.32g of arsenic trioxide and dissolve it in 20mL of sodium hydroxide solution (100g/L), dilute it to 100mL with water, and mix well.
4.70Oxalic acid solution (50g/L).
4.11Triammonium citrate solution (500g/L.). 4.32 Diethanolamine (1+1),
4.13 Disodium ethylenediaminetetraacetate (EDTA) solution (50 g/L) Approved by the State Administration of Quality and Technical Supervision on July 15, 199846
Implemented on February 1, 1999
GB/T 3254. 6--- 1998
4.143,3 Diaminobenzidine (selenium reagent) solution (5 g/L). Prepare it before use. 4.15 Selenium standard stock solution: Weigh 0.1000 g pure selenium into a 100 ml beaker, add 5 ml nitric acid (4.3), heat to dissolve in a boiling water bath and evaporate to dryness, cool; add water to dissolve selenium dioxide, transfer to a 1000 ml volumetric flask, dilute to scale with water, mix well, this solution contains 100 g selenium per ml.
4.16 Selenium standard solution: Pipette 10.00 ml of selenium standard storage solution (4.15) into a 200 ml volumetric flask. Dilute to the mark with water and irrigate evenly. This solution contains 5 μg of selenium per mL.
4.17 Metacresyl violet ethanol solution (1 g/L). 5 Instruments
Spectrophotometer.
6 Analysis steps
6.1 Test materials
Weigh the sample according to Table 1, accurate to 0.0001 g. Table 1
Selenium content, %
0. 000 50~0. 003 0
>0. 003 0~ 0. 008 0
>0. 008 0~0. 020
≥0.020~0.040
Carry out two independent determinations and take the average value. 6.2 Blank test
Carry out a blank test with the sample.
6.3 DeterminationWww.bzxZ.net
Sample amount·g
6.3.1 Place the sample (6.1) in a 100ml beaker, add 5ml hydrochloric acid (4.2), 3ml ammonium persulfate solution, and 0.1ml silver nitrate solution, shake gently to dissolve most of the sample, heat at low temperature to dissolve and boil for 30s, remove and cool. 6.3.2 Add 1mL arsenic solution, 5.0mL oxalic acid solution, 10.0mL ammonium citrate solution, 2.0mL triethanolamine, and 2mL EDTA solution, and mix well.
6.3.3 Add 0.1mL m-cresol violet ethanol solution, and adjust the solution to light red (pH 1-3) with ammonia water (4.4). Add 3mL selenium reagent solution, heat in a boiling water bath for 5min, color, and remove and cool. 6.3.4 Adjust the acidity of the solution to pH 6.0-8.0 with ammonia water (4.4). Transfer to a 125mL separatory funnel, wash the beaker with a small amount of water. Add the washing liquid to the separatory funnel, add 15.0mL methyl methacrylate, shake for 1min, let stand to separate, and discard the aqueous phase. 6.3.5 Filter part of the solution (6.3.4) through cotton wool and transfer it into a 2 cm absorbent dish. Using the blank test solution accompanying the sample as a reference, measure the absorbance of the solution at a wavelength of 430 nm on a spectrophotometer and find out the corresponding amount of selenium from the working curve. 6.4 Drawing of the working curve
6.4.1 Transfer 0, 1.00, 2.00, 4.00, 6.00, and 8.00 mL of the selenium standard solution to a set of 100 ml beakers, dilute with water to 20 ml, add 2 drops of hydrochloric acid (4.5), and proceed as in 6.3.3 to 6.3.4. 6.4.2 Filter part of the solution (6.4.1) through cotton wool and transfer it into a 2 cm absorbent dish. Using the reagent blank solution as a reference, measure the absorbance of the solution at a wavelength of 430 nm on a spectrophotometer. The working curve is drawn with the amount of selenium as the horizontal axis and the absorbance as the vertical axis. The expression of the analysis results
The percentage of selenium is calculated according to formula (1):
GB/T32546-1998
Se(%)=
Wherein: m is the amount of selenium found from the working curve, ug: m—the mass of the sample·g.
m×10-
The result is expressed to three decimal places. If the selenium content is less than 0.010%, it is expressed to four decimal places. The difference between the analysis results of laboratories should not be greater than the allowable difference listed in Table 2. Table 2 | | tt | 040
Allow difference
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