This standard is applicable to the determination of sulfur content in ferrosilicon. Determination range: 0.005_ 0.025%. This standard complies with GB 1467-78 "General Principles and General Provisions of Standards for Chemical Analysis Methods of Metallurgical Products". GB 4333.7-1984 Chemical Analysis Method for Ferrosilicon Determination of Sulfur Content by Chromatographic Separation and Barium Sulfate Gravimetric Method GB4333.7-1984 Standard Download Decompression Password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical analysis of ferrosiliconThe chromatographic separationdon-barium sulfategravimetric method .for the detevmination ofsulfur content
This standard is applicable to the determination of sulfur content in ferrosilicon. Determination range: 0.005～0.025%. This standard complies with GB1467--78 "General Principles and General Provisions of Chemical Analysis Methods for Metallurgical Products". 1 Method Summary
UDC 669.15' 782
: 548.21: 546
GB 4333.7--84
The sample is dissolved in bromine solution with nitric acid and hydrofluoric acid, and filtered after fuming with perchloric acid and dissolving salts with water. The filtrate is passed through an activated alumina chromatography column to remove most interfering elements, and the sulfate ions on the chromatography column are eluted with dilute ammonium hydroxide, and then the sulfur is determined by the barium sulfate gravimetric method.
2 Reagents and materials
Boric acid.
Nitric acid (specific gravity 1.42).
Hydrofluoric acid (specific gravity 1.15).
Perchloric acid (specific gravity 1.67).
Perchloric acid (1+100).
Glacial acetic acid (specific gravity 1.05).
Hydrochloric acid (1+1).
Hydrochloric acid (1+20).
Ammonium hydroxide (1M).
2.10 Ammonium hydroxide (0.1M).
2.11 Bromine (more than 99%).
2.12 Hydrogen peroxide (specific gravity 1.10).
Absolute ethanol (99.5%).
2.14 Ammonium nitrate solution (0.5%).
2.15 Silver nitrate solution (1%).
2.16 Chloride solution (10%): Filter through slow filter paper and set aside. 2.17 Methyl red ethanol solution (0.1%). 2.18 Sulfur standard solution: Weigh 1.1200g of potassium sulfate (superior purity) that has been dried to a constant amount at 105℃ in advance, place it in a beaker, add water to dissolve it, transfer it to a 500ml volumetric flask, dilute it with water to the scale, and mix it. 1ml of this solution is equivalent to 3.00mg of barium sulfate. 2.19 Activated alumina: Activated alumina with a particle size of less than 80 days should be soaked in 1M hydrochloric acid for several hours, then rinsed with clean water several times, and each time the fine particles that have not settled within 10s after shaking should be poured off and set aside. 2.20 Cotton wool.
National Bureau of Standards Issued on April 9, 1984
Implemented on March 1, 1985
3 Apparatus
3.1 Alumina chromatography separation apparatus (see figure). GB 4333.7-84
Connected to mechanical pump
1-dryer, 2-beaker; 3-absorbent cotton; 4-alumina; 5-soft plastic tube3.2 Preparation of chromatographic column: Put a small amount of absorbent cotton at the bottom of a 25ml burette, and then transfer the activated alumina (2.19) into the burette with a small amount of water, the height of which is 80-100mm, and put a small amount of absorbent cotton at the top of the activated alumina column. Wash and pass the chromatographic column with 50ml hydrochloric acid (2.8) three times, and then wash the chromatographic column twice with 30ml water, and discard the washing liquid. The following shall be carried out according to Section 5.3.5. Add 5 ml of barium chloride solution (2.16) dropwise. If no barium sulfate precipitate appears at the bottom of the cup, it is OK (otherwise, it should be washed repeatedly). The used chromatographic column can be regenerated by passing 20 ml of water and 10-15 ml of hydrochloric acid (2.8) through the chromatographic column for use. After analyzing about 18 samples, the alumina of the chromatographic column needs to be soaked in 1M hydrochloric acid for several hours before it can be used multiple times. , Sample
The sample should pass through a 120-mesh sieve.
5 Analysis steps
5.1 Sample amount
When the sulfur content in the sample is 0.010-0.025%, weigh 5.000 g of the sample. When the sulfur content is 0.005-0.010%, weigh two samples, each weighing 5.000 g of the sample.
5.2 Blank test
Carry out two blank tests with the sample and take the average value. 5.3 Determination
5.3.1 Place the sample (5.1) in a 600ml polytetrafluoroethylene beaker. Add 100ml nitric acid (2.2), 5ml bromine (2.11), and then add 1-2ml hydrofluoric acid (2.3). Heat on a low temperature electric hot plate until the reaction begins, remove, and add 50-60ml hydrofluoric acid (2.3) dropwise to slowly decompose it. Add 50ml perchloric acid (2.4), rinse the wall of the cup with a small amount of water, heat and evaporate until perchloric acid fumes appear and concentrate the solution volume to about 30ml. Remove and cool slightly, rinse the wall of the cup with a small amount of water, continue to heat until perchloric acid fumes appear, and make the solution volume about 20ml, remove and cool. Add 150ml water and 0.1g boric acid (2.1), heat to dissolve the salts, and keep warm for 20min. 5.3.2 Filter with medium-speed quantitative filter paper, and wash the polytetrafluoroethylene beaker and filter paper with perchloric acid (2.5) 4 to 5 times, control the volume of the solution to about 200 ml (combine the filtrate and washing liquid obtained from the two samples with a sulfur content of 0.005~0.010%), and accurately add 2.00 ml of sulfur standard solution (2.18).
Note: 2.00 ml of sulfur standard solution (2.18) should be added to both blank tests of the accompanying sample. 5.8.3 Pass the solution (5.3.2) through the chromatographic column, and control the flow rate at 10~15 ml/min. 5.3.4 After the solution has completely passed through the chromatographic column, wash the beaker with 50 ml of hydrochloric acid (2.8) three times and pass it through the chromatographic column. Wash the column twice with 30 ml of water, and discard the solution and washing liquid flowing out of the column. 5.3.5 Use 10 ml of ammonium hydroxide (2.9) and 35 ml of ammonium hydroxide (2.10) to elute the sulfate ions on the column, and control the flow rate at 5 ml/min. Collect the eluate in a 100 ml beaker (if there are impurities such as aluminum oxide, they must be filtered out, wash the beaker and filter paper with water 5 to 6 times, and concentrate the solution at low temperature to a volume of about 45 ml), add a drop of methyl red ethanol solution (2.17), and add hydrochloric acid (2.7) until a stable red color appears and an excess of 0.50 ml. 5.8.6 Add 1 ml of glacial acetic acid (2.6) and 5 drops of hydrogen peroxide (2.12) to reduce and complex the small amount of chromium ions under the band. After the blue color completely fades, add 10 ml of anhydrous ethanol (2.13) and stir. Heat to near boiling, add 5 ml of barium fluoride solution (2.16), and stir until a precipitate appears. Keep warm at 60-70℃ for 2h or let stand overnight. 5.8.7 Filter with 9cm slow quantitative filter paper. Use hot water to transfer all the precipitate onto the filter paper (generally need to rinse the beaker 6-7 times, about 2ml each time). Wash the filter paper and precipitate with ammonium nitrate solution (2.14) until there is no chloride ion (generally need to rinse 12-13 times, about 2ml each time), and check with silver nitrate solution (2.15). bZxz.net
5.$. Transfer the precipitate and filter paper to a platinum crucible that has been burned to a constant weight, ash at low temperature, burn in a high temperature furnace at 800-850℃ for more than 30min, take out, place in a desiccator, cool to room temperature, and weigh. Repeat burning to a constant weight (m). 5.4 Drawing of calibration curve
Take several portions of sulfur standard solution (2.18) (equivalent to 1-15 mg sulfuric acid, take two portions each), place in a 100 ml beaker, add 13.5 ml of ammonium hydroxide (2.9), add a drop of methyl red ethanol solution (2.17), neutralize with hydrochloric acid (2.7) until a stable red color appears and an excess of 0.5 ml, dilute with water to a volume of about 45 ml, and proceed as in 5.3.6 to 5.3.8. Draw a calibration curve with the amount of sulfur added (equivalent to the theoretical value of barium sulfate in milligrams) as the abscissa and the difference (i.e., the calibration value) obtained by subtracting the theoretical value from the average value of the measured barium sulfate (in milligrams) as the ordinate.
6 Calculation of analysis results
Calculate the percentage of sulfur according to the following formula:
s (%) =(ml=m2)=(m3=m×0.1374×100)Wherein: m1-the mass of barium sulfate measured in the sample, g; m
m2-the correction value obtained from the calibration curve in m, gm3-the mass of barium sulfate in the blank test (including the sulfur added in terms of barium sulfate) made with the sample, g; m4
? Allowable difference
the correction value obtained from the calibration curve in m3, gsSample weight, g
Conversion factor for converting barium sulfate to sulfur.
0.0050-0.0250
Additional Notes:
GB 4333.7-84
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by Shanghai Ferroalloy Factory. This standard was drafted by Shanghai No. 5 Iron and Steel Plant. The main drafters of this standard are Ding Zhongjia and Yang Longxing. From the date of implementation of this standard, the determination of sulfur content in the former Ministry of Metallurgical Industry Standard YB72-65 "Chemical Analysis Method of Ferrosilicon" will be invalid. 112
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