GB/T 3254.5-1998 Chemical analysis method for antimony trioxide - Determination of iron content

This standard specifies the determination method of iron content in antimony trioxide. This standard is applicable to the determination of iron content in antimony trioxide. Determination range: 0.000 20% to 0.010%. GB/T 3254.5-1998 Chemical analysis method for antimony trioxide Determination of iron content GB/T3254.5-1998 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 iron content
Antimony trioxide Determination of iron contentThis standard specifies the determination method of iron content in antimony trioxideGB/T3254.5--1998
This standard is applicable to the determination of iron content in antimony trioxide. Determination range: 0.00020%~~0.010%. 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 Standardization work guidelines 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 dissolved with hydrochloric acid and hydrobromic acid and evaporated to remove antimony. The residue is dissolved with hydrochloric acid. The acidity of the color development is controlled with sodium acetate solution. Hydroxylamine hydrochloride is added to reduce the high-valent iron to divalent iron to form a colored complex with o-phenanthroline. The absorbance is measured at a wavelength of 510 nml on a spectrophotometer. 4 Reagents
4.1 Hydrochloric acid (pl.19 g/ml).
4.2 Hydrobromic acid (p1.48 g/mL)
4.3 Nitric acid (p1.42 g/mL).
4.4 Hydrochloric acid (1+1).
4.5 Potassium sodium tartrate solution (100g/L): Weigh 100g potassium sodium tartrate (KNaC,H,0.·4H.O) and place in a 1000ml beaker, add 500mL water and heat to dissolve, add 20ml hydroxylamine hydrochloride solution, 20mL o-phenanthroline solution, boil for 2min. Remove and cool to room temperature, add 10ml potassium thiocyanate solution (200g/L), transfer to a 1000mL separatory funnel, add trifluoromethane (10ml each time) in batches, shake and extract until the organic layer is colorless. Discard the organic layer. Transfer the aqueous phase into a glass bottle and dilute to 1000ml with water, mix well. 4.6 Sodium acetate solution (300g/L): Weigh 300g of anhydrous sodium acetate and place it in a 1000mL beaker, add 650ml of water and heat to dissolve, after purification (purification method, see 4.5), dilute with water to 1000ml, and mix. 4.7 Hydroxylamine hydrochloride solution (100g/L): Weigh 100g of hydroxylamine hydrochloride and place it in a 1000mL beaker, add 500ml of water to dissolve, adjust the pH to about 7 with ammonia water (p0.90g/mL), add 20ml of o-phenanthroline solution (4.8), boil for 2min, remove and cool to room temperature. Add 20ml potassium thiocyanate solution (200g/L), transfer to 1000ml separatory funnel, add chloroform (10ml each time) in batches, shake and extract until the organic layer is colorless, discard the organic layer, transfer the aqueous phase into a glass bottle and dilute with water to 1000ml. Mix well. 4.8 o-Phenanthroline solution (2.5g/L).
Approved by the State Administration of Quality and Technical Supervision on July 75, 1998, implemented on February 1, 1999
GB/T 3254.5.-. 1998
4.9 Iron standard stock solution: Weigh 0.1000g pure iron (99.99%) into a 1100ml beaker, add 10ml nitric acid (11:. Heat slightly and dissolve until clear. Boil for 1min to drive off nitrogen oxides, remove and cool. Transfer to a 1000ml volumetric flask, wash the beaker with water and dilute to the mark, mix well. This solution contains 100g iron in 1ml. 4.10 Iron standard solution: Pipette 10.00 ml of the iron standard stock solution (4.9) into a 250 ml volumetric flask and dilute to the mark with water. Mix about 1 ml of this solution to contain 4 μg of iron.
5 Instruments
Spectrophotometer.
6 Analysis steps
6.1 Samples
Weigh the sample according to Table 1. Accurate to 0.0001 g: Table 1
Iron content, %
0. 000 20~- 0. 001 0
0. 001 00. 002 0
Sample quantity name
Independently conduct: times of determination and take the average value. 6.2 Empty self-test
Carry out empty self-test with the sample.
6.3 Determination
Iron content.%
≥ 0. 002 0~~ 0. 005 0
>0. 005 0~0. 010
Test material
6.3.1 Place the test material (6.1) in a 100ml beaker. Add 10ml of pannic acid (4.1). Heat at low temperature to dissolve and evaporate slowly to dryness. Remove and cool slightly, then add 5ml of hydrochloric acid (4.1) and 1ml of hydrobromic acid, evaporate slowly to dryness, remove and cool slightly; add 2ml of hydrochloric acid (4.4) and 1ml of nitric acid, evaporate to dryness at low temperature, cool slightly,
6.3.2 Add 2ml of hydrochloric acid (4.4) and 5ml of potassium sodium tartrate solution, heat and boil to dissolve the residue, remove and cool. 6.3.3 Transfer the test solution to a 25ml volumetric flask, add 5ml of sodium acetate solution, 2ml of hydroxylamine hydrochloride solution, and 2ml of o-phenanthroline solution, and mix well. Boil in a boiling water bath for 2 minutes, cool Cool to room temperature. Dilute to scale with water. Mix well. 6.3.4 Transfer part of the solution (6.3.3) into a 3 cm absorbent dish, using the blank test solution accompanying the sample as a reference. Measure the absorbance at a wavelength of 510 nm on a spectrophotometer. Find the corresponding amount of iron on the working line. 6.4. Plotting the curve
6.4.1 Transfer 0.1.00.2.00, 3.00.4.00.5.00.6.00 ml of the standard iron solution into a 25 ml volumetric flask, dilute to 10 ml with water, add 2 ml of hydrochloric acid (4.4), and proceed as in 6.3.3. 6.4.2 Transfer part of the solution (6.4.1) into a 3 cm absorbent dish, using the reagent blank as a reference, and measure the absorbance at a wavelength of 510 nm on a spectrophotometer. Plot the working curve with the amount of iron as the horizontal axis and the absorbance as the vertical axis. 7 Expression of analysis results
Calculate the percentage of iron according to formula (1):
Fe(%)×10*%
Where\…The amount of iron found from the working curve, g; m
The mass of the sample, g.
The result is expressed to three decimal places. If the iron content is less than 0.010%, it is expressed to four decimal places. 1:1
Allowable difference
GB/T3254.5—1998Www.bzxZ.net
The difference in the analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
Iron content
0.0010~~0.0050
>0. 005 0 0. 010
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