GB/T 4373.2-1984 Chemical analysis method for arsenic - Malachite green photometric method for determination of antimony content GB/T4373.2-1984 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical analysis of arsenicThe malachite green photometric methodfor the determination of antimony contentThis standard is applicable to the determination of antimony content in arsenic. Determination range: 0.010~0.450%. UDC 669.778 : 543
.42:546.86
GB4373.2-84
This standard complies with GB1467-78 "General Principles and General Provisions of Standards for Chemical Analysis Methods of Metallurgical Products" Method Summary
The sample is heated and dissolved in sulfuric acid and then evaporated to dryness, dissolved in hydrochloric acid, reduced with stannous chloride in a separatory funnel, and antimony is oxidized to pentavalent by sodium nitrite. In a medium of about 1.5N hydrochloric acid, malachite green is added to develop color, extracted with benzene, and its absorbance is measured at a wavelength of 625mm on a spectrophotometer. 2 Reagents
2.1 Sulfuric acid (specific gravity 1.84).
2.2 Hydrochloric acid (2+1).
2.3 Sodium nitrite solution (10%).
2.4 Urea solution (50%).
2.5 Stannous chloride solution: weigh 10g of stannous chloride, place it in a 250ml beaker, add 67ml of hydrochloric acid (specific gravity 1.19) to dissolve it, dilute it to 100ml with water, and mix it.
2.6 Malachite green solution (0.1%): weigh 0.10g of malachite green, place it in a 150ml beaker, add 50ml of ethanol and 50ml of water to dissolve it, filter it into a brown bottle, and mix it. 2.7 Antimony standard stock solution: Weigh 0.5000g pure antimony (99.9% or more), place in a 250ml beaker, add 10ml sulfuric acid (2.1), cover with table III l, heat on an electric stove to dissolve, continue heating until sulfuric acid smoke is emitted and evaporated until the solution volume is about 2ml, remove and cool to table temperature, add a small amount of hydrochloric acid (2.2) to dissolve the salts and transfer to a 1000ml volumetric flask 1, wash the tableware and beaker with hydrochloric acid (2.2) several times, and transfer to the volumetric flask, dilute to the scale with hydrochloric acid (2.2), and mix well. This solution contains 0.50mg antimony in 1ml. 2.8 Antimony standard solution: Transfer 4.00ml antimony standard stock solution (2.7), place in a 500ml volumetric flask, dilute to the scale with hydrochloric acid (2.2), and mix well. This solution contains 0.004mg antimony in 1ml. 2.9 Benzene.
2.10 Anhydrous ethanol.
3 Instrument
Spectrophotometer.
4 Sample
4.1 Arsenic samples shall be sieved through a 80-mesh sieve, and the diameter of the sieve shall not be greater than 2mm. 4.2 After processing, the sample shall be stored in a desiccator and weighed for analysis on the same day, and the sample shall be weighed according to the ratio of the sieve to the sieve:3:【. National Bureau of Standards Issued on April 30, 1984
19850401 Implementation
5 Analysis steps
5.1 Determination quantity
GB4373-2-84
Weigh two samples for determination and take the average value. 5.2 Sample quantity
Weigh the sample
antimony quantity according to Table 1,
0.01 ~0. 08
0.08 ~ 0. 20
~0.20 ~0.45
5.3 Blank test
Carry out a blank test together with the sample.
5.4 Determination
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Pipette the solution, ml
5.4.1 Place the sample (5.2) in a 100ml beaker, add 5ml sulfuric acid (2.1), cover with a watch glass, heat to dissolve the sample, continue heating and evaporating until nearly dry, remove and cool. Add 20-30ml hydrochloric acid (2.2) to dissolve the salts, transfer to a 100ml volumetric flask, wash the beaker with hydrochloric acid (2.2) and transfer to the volumetric flask, dilute to the mark with hydrochloric acid (2.2), and mix. 5.4.2 Transfer the solution according to Table 1 to a 150ml separatory funnel [add 3.00ml hydrochloric acid (2.2) when transferring 4.00ml solution], add stannous chloride solution (2.5) dropwise until the yellow color of the solution fades and 2 drops are added in excess, and let stand for 5min. 5.4.3 Add 2ml sodium nitrite solution (2.3), mix, and let stand for 10-15min. Add 2ml urea solution (2.4) and shake to drive away a large number of bubbles, add 25ml water, add 1.00ml malachite green solution (2.6), and mix. Immediately add 10.0ml benzene (2.9), shake for 30s, let stand for stratification, and discard the aqueous phase. Transfer the organic phase to a 25ml dry colorimetric tube. 5.4.4 Add 5 drops of anhydrous ethanol (2.10) and transfer part of the solution to a 1cm colorimetric tube III. 5.4.5 Using the blank accompanying the sample as a reference, measure its absorbance at a wavelength of 625nm on a spectrophotometer. Find the corresponding antimony amount from the curve in .1.
5.5 Drawing of the working curvewww.bzxz.net
Pipette 0.00, 1.00, 2.00, 3.00, and 4.00ml of the antimony standard solution (2.8) and place them in a 150ml separating funnel respectively, add hydrochloric acid (2.2) to a solution volume of 7ml, add 2 drops of stannous chloride solution (2.5), and let stand for 5min. The following is carried out according to 5.4.3 to 5.4.4. Using the reagent blank as a reference, measure its absorbance. Draw a working curve with the antimony amount as the horizontal axis and the absorbance as the vertical axis. 6 Calculation of analysis results
Calculate the percentage of antimony as follows:
Sb (%)
Antimony amount found from the working curve, mg?
Where: m,--
Sample amount, g;
V—volume of the removed solution, ml.
Analysis results are expressed to three decimal places. 296
m/×10
Allowance
GB4373.2-84
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
0.010 ~ 0.040
0.040 ~ 0.080
0.080 ~ 0.200
0.200 ~ 0.450
Additional remarks:
This standard was proposed by China Nonferrous Metals Industry Corporation. This standard was drafted by the Hunan Shuikoushan Mining Bureau. This standard was drafted by the Research Institute of the Hunan Shuikoushan Mining Bureau. The main drafters of this standard were Ling Zonggan and Liu Binbin.
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