This standard is applicable to the determination of sulfur content in manganese silicon alloy. Determination range: 0.015% ~ 0.045%. This standard complies with GB 1467-78 "General Principles and General Provisions of Chemical Analysis Methods for Metallurgical Products". GB/T 5686.8-1988 Chemical Analysis Method for Manganese Silicon Alloy Combustion Neutralization Titration Method for Determination of Sulfur Content GB/T5686.8-1988 Standard Download Decompression Password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method of silicomanganese ailoy
Determination of sulfur content by combustion-neutralization titration method
Methods for chemical analysis of silicomanganese ailoyThe combustion-neutralization titration methodfor the determination of sulfur contentThis standard is applicable to the determination of sulfur content in silicomanganese ailoy. Determination range: 0.015%~0.045%UDC669.74°782
GB5686.8-88
This standard complies with GB【467--78 "General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products". 1 Method Summary
The sample is burned with oxygen at high temperature to oxidize all sulfur into sulfur dioxide, which is absorbed in hydrogen peroxide solution to become sulfuric acid, which is titrated with sodium hydroxide standard solution.
2 Reagents and materials
The water used in this standard is distilled water that has been boiled to drive out carbon dioxide and cooled. 2.1 Oxygen: purity greater than 99.5%.
2.2 High temperature combustion tube: Φ×L, mm; 20~24×600. 2.3 Porcelain boat: pre-burn in a high temperature combustion tube at 1400C with oxygen for 5 minutes, cool and set aside. 2.4 High purity vanadium pentoxide: sulfur content less than 0.0015%. 2.5 Tin particles: sulfur content less than 0.0015%.
2.6 Silica gel, activated alumina or magnesium perchlorate. 2.7
Soda lime or sodium hydroxide: granular. bzxZ.net
2.8 Chromic acid saturated sulfuric acid: add potassium dichromate or anhydrous chromic acid to sulfuric acid (p1.84g/mL) to saturate it, and use the upper clear solution.
Absorption solution: transfer 3.5mL hydrogen peroxide (30%) and dilute it to 1000mL with water, mix. 2.10 Mixed indicator: Weigh 0.125g methyl red and 0.083g methylene blue, dissolve in anhydrous ethanol and dilute to 100mL. 2.71 Aminosulfonic acid standard solution
Weigh about 0.1000g (accurate to 0.1mg) of aminosulfonic acid (NH,S0,H) with a purity greater than 99.90% that has been dried in a vacuum sulfuric acid dryer for about 48h in a 300mL beaker, dissolve it completely with 30mL water, transfer it to a 500mL brown volumetric flask, dilute to the mark with water, and mix well.
2.12 Sodium hydroxide standard solution: c (NaOH) = 0.005mol/L2.12.1 Preparation
Weigh 0.2000g sodium hydroxide and dissolve it in 1000mL water, add 1mL of newly prepared saturated barium hydroxide solution, mix well, isolate carbon dioxide and place for 2~~3 days, and take the upper clear solution when using. 2.12.2 Calibration
Pipette 20.00mL of aminosulfonic acid standard solution (2.11) into a 250mL conical flask, add 100mL of water, add 10 drops of bromothymol blue indicator (0.1%), and immediately titrate with sodium hydroxide standard solution (2.12.1) until the solution changes from yellow to blue and remains color-fast for 30 seconds.
2.12.3 Perform a blank test with 120mL of water starting from the addition of 10 drops of bromothymol blue indicator (0.1%) as in 2.12.2. The concentration of the sodium hydroxide standard solution is calculated according to formula (1): 1000×m·f×00
c = 97.093 X (V.- V.)
m·fx40
97.093× (VV)
Wherein: c——the molar concentration of the sodium hydroxide standard solution, mol/L; m
the amount of aminosulfonic acid, g;
f——the purity of aminosulfonic acid, % (m/m); V,-——the volume of the sodium hydroxide standard solution consumed during calibration, mL; V.-——the volume of the sodium hydroxide standard solution consumed in the blank test during calibration, mL; 97.093——the molar mass of aminosulfonic acid, nom/mol. 3 Instruments and devices
3.1 Sulfur determination device See Figure 1:
1-Oxygen cylinder; 2-Oxygen pressure gauge; 3-Flowmeter; 4-Buffer bottle: 5-Gas washing bottle, filled with chromic acid saturated sulfuric acid; 6-Drying tower, filled with soda lime or sodium hydroxide (granular); 7-Gas washing bottle, filled with sulfuric acid (p1.84g/mL); 8-Drying tower, filled with silica gel and activated alumina; 9-Two-way piston, 10-High temperature combustion furnace (about 300mm long); 11-Automatic temperature controller (with thermocouple), control the furnace temperature at 14001450℃ 12-High temperature combustion tube; 13-Porcelain boat; 14-Silica gel plug; 15-Desiccant tube; 16-Absorption bottle (without floating beads); 17-Reference solution; 18-Micro burette 3.2 Absorption bottle See Figure 2:
GB 5686.8—88
All manganese silicon alloy samples should pass through a 0.125 mm sieve. 5 Analysis steps
5.1 Sample quantity
Weigh 0.5000 g of sample.
5.2 Blank test
Perform a blank test according to 5.3 on a porcelain boat (2.3) pre-filled with 0.25 g of vanadium pentoxide (2.4) or 0.5 g of tin particles (2.5). 5.3 Determination
5.3.1 Connect all parts of the sulfur determination device and check for airtightness, and heat the high-temperature combustion tube (12) to raise the temperature inside the tube to 1400-~1450°C. 5.3.2 Transfer 40mL of absorption liquid (2.9) to the absorption bottle (16), add 5 drops of mixed indicator (2.10), and pass oxygen at a flow rate of 700~~900mL/min for about 5min to drive out all the carbon dioxide in the solution. If the solution is reddish purple at this time, add sodium hydroxide standard solution (2.12) until the solution is bright green.
5.3.3 Place the sample (5.1) in the porcelain boat (2.3), then push it into the central high-temperature part of the high-temperature combustion tube (12), plug the silicone plug (14) (pay special attention to the seal), and pass oxygen slightly to prevent the absorption liquid from flowing back. 5.3.4 Pass oxygen at a flow rate of 200 mL/min to allow the sample to burn for 3 min. Then, introduce oxygen at a flow rate of 700~~900 mL/min (inlet flow rate) into the absorption bottle (16) to absorb sulfur dioxide. After burning for 10 min, titrate with sodium hydroxide standard solution (2.12) until the solution changes from reddish purple to bright green. Then, intermittently pass oxygen for 5 min at an oxygen flow rate of 1000~1200 mL/min controlled by the two-way piston (9). If the solution is reddish purple, continue to titrate with sodium hydroxide standard solution (2.12) until it turns bright green. Stop passing oxygen, wash the drying tube 319
GB5686.8--—88
and the pipes at the connecting parts with the above absorption liquid, and introduce it into the absorption bottle. If the solution is reddish purple, continue to titrate with sodium hydroxide standard solution (2.12) until it turns bright green.
Calculation of analysis results
Calculate the percentage of sulfur according to formula (2): s(%) = (:-V) :c×0. 016 03 × 100mo
Wherein: V,——the volume of sodium hydroxide standard solution consumed when titrating the sample solution, mL; V,-——-the volume of sodium hydroxide standard solution consumed when titrating the blank test solution, mL; -the molar concentration of sodium hydroxide standard solution, mol/L; me
0. 016 03-
Allowance difference
-sample volume, nom;
～1.00mL1.000mol/L sodium hydroxide standard solution is equivalent to the molar mass of sulfur.g/mol. The difference in the analysis results between laboratories should not be greater than the allowable difference listed in the table below:
0.015~0.025
>0. 025~0. 045
Additional Notes:
This standard was drafted by Nanjing Ferroalloy Factory.
The main drafters of this standard are Wang Rude and He Jun.
From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB79-165 "Chemical Analysis Method of Manganese Silicon Alloy" will be invalid. 320
(2)
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