GB/T 15080.6-1994 Chemical analysis methods for antimony concentrates - Determination of selenium content
Some standard content:
UDC669.754 :543.06
National Standard of the People's Republic of China
GB/T15080.1~15080.9--94
Methods for chemical analysis of antimony concentrates
Published on 1994-05-11
Implemented on 1994-12-01
Published by the State Administration of Technical Supervision
National Standard of the People's Republic of China
Methods for chemical analysis of antimony concentrates
Selenium content【
Antimony concentrates-Determinationof selenium content
1 Subject content and scope of application
This standard specifies the method for determining the selenium content in antimony concentrate. This standard is applicable to the determination of selenium content in antimony concentrate. Determination range: 0.0015%~~0.2%. 2 Reference standards
GB1.4 Guidelines for standardization work Provisions for the preparation of chemical analysis methods GB1467 General principles and general provisions for chemical analysis methods for metallurgical products GB7729 General principles for spectrophotometric methods for chemical analysis of metallurgical products 3 Summary of methods
GB/T15080.6-94
The sample is decomposed with nitric acid and sulfuric acid. In a hydrochloric acid medium, sodium hypophosphite is used to reduce selenium (IV) to monomer selenium. Arsenic is used as a carrier and benzene is used to float arsenic-selenium precipitation to separate selenium from antimony and other coexisting impurities. Potassium bromate is added to oxidize the monomer selenium. After removing the excess potassium bromate, selenium (V) and selenium reagent form a colored complex, which is extracted with toluene and the absorbance is measured at a wavelength of 430nm on a spectrophotometer. 4 Reagents
4.1 Potassium nitrate.
4.2 Sodium hypophosphite.
4.3 Nitric acid (ol.42 g/mL).
4.4 Benzene.
4.5 Toluene.
4.6 Ammonia water (p0.90g/mL).
4.7 Sulfuric acid: Take 500mL sulfuric acid (p1.84g/mL) and place it in a 1000mL beaker, add 1g sodium bromide, mix well, heat and smoke until the sulfuric acid becomes colorless, and cool.
4.8 Hydrochloric acid (1+1).
4.9 Hydrochloric acid (1+2).
4.10 Ammonia water (1+1).
4.11 Ammonia water (1+4).
4.12 Arsenic solution (3.8g/L): Weigh 0.5g of dioxide and dissolve it in 10mL of sodium hydroxide solution (100g/L), add 50mL of water and 5mL of hydrochloric acid (4.8), dilute to 100mL with water, and mix well. 4.13: Cupric chloride solution (20 g/L) Weigh 2 g of copper chloride (CuCl2·2H2O), dissolve it in hydrochloric acid (4.8), dilute it to 100 mL with hydrochloric acid (4.8), and mix well.
Approved by the State Administration of Technical Supervision on May 11, 1994, and implemented on December 1, 1994
4.14 Potassium bromate solution (10 g/L).
GB/T 15080.6—94
4.15 Disodium ethylenediaminetetraacetic acid (EDTA) solution (50 g/L). 4.16 3,3'-Diaminobenzidine (selenium reagent) solution (5 g/L), prepare it when needed. 4.17 Selenium standard stock solution: Weigh 0.1000g selenium (99.99%) and place it in a 100mL beaker, add 5mL nitric acid (4.3), heat in a boiling water bath to dissolve and evaporate to dryness, cool, add water to dissolve selenium dioxide, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix. This solution contains 100 μg selenium per ml.
4.18 Selenium standard solution: Transfer 10.00mL selenium standard stock solution (4.17) to a 200mL volumetric flask, dilute to scale with water, and mix. This solution contains 5μg selenium per ml.
4.19 Metacresol purple indicator (1/L), prepared with ethanol. 5 Instruments
Spectrophotometer.
6 Samples
6.1 The sample particle size should be less than 0.100mm.
6.2 The sample should be dried at 100-105℃ for 1h, and then placed in a desiccator to cool to room temperature. 7 Analysis steps
7.1 Sample
Weigh the sample according to Table 1, accurate to 0.0001g. Table 1
Selenium content, %
0.001 5~~0. 010
>0.010~0.050
>0. 050~0. 200
7.2 Blank test
Carry out a blank test along with the sample.
7.3 Determination
Sample amount, g
Transfer solution volume, mL
7.3.1 Place the sample (7.1) in a 300mL conical flask, moisten with a small amount of water, add 30mL nitric acid (4.3), heat and dissolve on a low-temperature electric hot plate, and evaporate to about 10mL, remove and cool, add 1~~1.5g potassium nitrate (4.1) and 10mL sulfuric acid (4.7), heat to drive off nitrogen oxides, cover the surface with blood, dissolve for 1h at a temperature that does not make white sulfuric acid smoke come out of the bottle mouth and keeps the solution slightly boiling, remove and cool. 7.3.2 Add 10mL water and 10mL hydrochloric acid (4.8) and heat to boil, remove and cool to room temperature, transfer to a 50mL volumetric flask, dilute to scale with hydrochloric acid (4.8), mix well, and dry filter. 7.3.3 Pipette the solution according to Table 1 into a 100mL beaker, dilute to 20mL with hydrochloric acid (4.8), add 0.20mL of monument solution (4.12), 1mL of cupric chloride solution (4.13), 1~~2g of sodium hypophosphite (4.2), mix well, heat until selenium coprecipitates and keep for about 30s, remove and cool.
7.3.4 Transfer the test solution (7.3.3) into a 125mL separatory funnel, wash the beaker with about 10mL of hydrochloric acid (4.8) in batches, and add the washing liquid into the separatory funnel. Add 15mL of benzene (4.4), shake for 1min, let stand to separate, and discard the aqueous phase. Add 10mL of hydrochloric acid (4.8) and 10mL of water in sequence to wash the organic phase once each time, shake for 15s each time, let stand to separate, and discard the aqueous phase. 7.3.5 Add 10 ml of hydrochloric acid (4.9) and 0.25 ml of potassium bromate solution (4.14), shake for 1 min to completely dissolve the arsenic and selenium precipitate in the aqueous phase, let stand to separate the layers, and put the aqueous phase into the original beaker. Add 10 ml of water to the separatory funnel, shake for 15 s, wash the organic phase, add the washing liquid to the beaker, and discard the organic phase.
GB/T 15080.6---94
7.3.6 Add 0.8 ml of arsenic solution (4.12) to the beaker containing the aqueous phase, reduce the excess potassium bromate, and add 2 ml of LEDTA solution (4.15).
7.3.7 Add 2 drops of m-cresol purple indicator (4.19), adjust the solution to light red (pH 1-3) with nitrogen water (4.6), add 3 mL of selenium reagent solution (4.16), heat in a boiling water bath for 5 min to develop color, and cool. 7.3.8 Adjust the acidity of the solution to pH 6.0-8.0 with ammonia water (4.10) and (4.11) respectively. Transfer to a 60 mL separatory funnel, wash the beaker with water, and add the washing liquid to the separatory funnel, with a total volume of about 35 mL, add 15.0 mL of toluene (4.5), shake for 1 min, let stand to separate, and discard the aqueous phase. 7.3.9 Filter part of the solution (7.3.8) through absorbent cotton, transfer to a 2 cm colorimetric tube, use the blank solution accompanying the sample as a reference, measure the absorbance at a wavelength of 430 nm on a spectrophotometer, and find the corresponding amount of selenium from the working curve. 7.4 Drawing of working curve
7.4.1 Take 0, 1.00, 2.00, 4.00, 6.00, 8.00, 10.00mL of selenium standard solution (4.18) and place them in a group of 100mL beakers respectively, dilute to 20mL with water, add 2 drops of hydrochloric acid (4.8), and perform the following operations according to 7.3.7 and 7.3.8. 7.4.2 Filter part of the solution (7.4.1) through absorbent cotton and transfer it into a 2cm cuvette. Take the reagent blank as reference and measure the absorbance at a wavelength of 430nm on a spectrophotometer. Draw the working curve with the amount of selenium as the horizontal axis and the absorbance as the vertical axis. 8 Expression of analysis results
Calculate the percentage of selenium according to the following formula:
Se(%) = mt : V. : 10~6
-× 100
Wherein: m~-—the amount of selenium found from the working curve, μg; V. Total volume of solution, mL;
V,—volume of solution transferred, mL;
mass of the sample, g.
The analysis result is expressed to three decimal places, less than 0.010% is expressed to four decimal places. 9 Allowable difference
The difference between the analysis results of laboratories should not be greater than the allowable difference listed in Table 2. Table 2
Selenium contentwwW.bzxz.Net
>0. 005 0~0. 010 0
>0.010~~0.030
>0. 030~0. 050
>0. 050~0. 100
>0. 100~0. 200
Allowable difference
Additional instructions:
GB/T15080.6—94
This standard is proposed by China Nonferrous Metals Industry Corporation. This standard is under the technical jurisdiction of Beijing Research Institute of Mining and Metallurgy. This standard is drafted by Xikuangshan Mining Bureau and Hunan Nonferrous Metals Research Institute. This standard was drafted by Xikuangshan Mining Bureau.
The main drafters of this standard are Zheng Chunheng and Zeng Fusheng. 22
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