GB/T 4701.11-1988 Chemical analysis methods for ferrotitanium - Combustion neutralization titration method for determination of sulfur content

GB/T 4701.11-1988 Chemical analysis method for ferrotitanium - Determination of sulfur content by combustion neutralization titration GB/T4701.11-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical analysis of ferrotitaniunThe cmbustion-neutralizatlon tltration nethodfor the determinatlon of sulfur content
Methods for chemical analysis of ferrotitaniunThe cmbustion-neutralizatlon tltration nethodfor the determinatlon of sulfur contentThis standard is applicable to the determination of sulfur content in ferrotitaniun. Determination range: ≤0.070%. UDC 669. 15' 295
GB 4701. 11—88
This standard complies with GB1467-78 "General Measurement and General Provisions of Chemical Analysis Methods for Metallurgical Products". 1 Summary of the method
The sample is burned in an oxygen stream to oxidize all sulfur into sulfur dioxide, which is absorbed in peroxide to become sulfuric acid, and titrated with a sodium hydroxide standard solution.
2 Reagents and materials
The reagents used in this standard are all distilled water that has been boiled to drive out all carbon dioxide and cooled. 2.1 Oxygen: purity greater than 99.5%.
2.2 High temperature combustion tube: Φ×Lmm20~24×6002.3 Porcelain boat, pre-burned in a high temperature combustion tube at 1400℃ with oxygen for 5 minutes, cooled and set aside. 2.4 High purity iron: powder, sulfur content less than 0.0010%. 2. 5 Silica gel, activated alumina or magnesium perchlorate2.6 Alkali or sodium hydroxide: granular.
2.7 Chromic acid saturated sulfuric acid: add potassium dichromate or anhydrous chromic acid to sulfuric acid (p1. 84 g/mL) to saturate it, and use the supernatant. 2.8 Absorption liquid: transfer 3.5mL peroxide (30%). Dilute to 1000mL with water and filter evenly. 2.9 Mixed indicator: weigh 0.1250g methyl red and 0.0830g soft methyl blue, dissolve in anhydrous ethanol and dilute to 100mL. 2.1D Aminosulfonic acid standard solution
Weigh about 0.1000 g (accurate to 0.1 ng) of aminosulfonic acid (NH,SO,H) with a purity greater than 99.90% that has been dried in a vacuum sulfuric acid dryer for about 48 hours in a 300mL beaker, dissolve it completely with 30mL of water, transfer it to a 500mL brown volumetric flask, dilute to the mark with water, and mix.
2.11 Sodium hydroxide standard solution: c(NaOH)=0.005 mol/L, 2.11.1 Preparation
Weigh 0.2000g of sodium hydroxide and dissolve it in 1000mL of water, add 1mL of newly prepared saturated barium hydroxide solution, mix well, and leave it in an atmosphere of carbon dioxide for 2 to 3 days. Take the upper clear liquid when using. 2.11.2 Calibration
Pipette 20.00mL aminomagnetic acid standard solution (2.10) into a 250mL conical flask, add 100mL water, add 10 drops of bromothymol blue indicator (0.1%), and immediately titrate with sodium hydroxide standard solution (2.11.1) until the solution changes from yellow to pure blue and remains unchanged for 30 seconds. Www.bzxZ.net
Approved by the Ministry of Metallurgical Industry of the People's Republic of China on February 2, 1988 and implemented on March 1, 1989
GB 4701. 11-88
2.11. Perform a micro-blank test with 120mL water starting from the addition of 10 drops of bromothymol blue indicator (0.1%) as in 2.11.2. The concentration of the sodium hydroxide standard solution is calculated according to formula (1), 1000×m××
97. 093 X (V, -V.)
wherein: r—
mXfx40
97. 093 × (, -V.)
the molar concentration of the sodium hydroxide standard solution, mol/L, m—the weighed amount of aminosulfonic acid, 8
a—the purity of aminosulfonic acid, % (bo/m); …the volume of the sodium hydroxide standard solution consumed during the calibration, mL, V. —the volume of the sodium hydroxide standard solution consumed during the blank test during calibration, mL, 97.093-
the molar mass of aminosulfonic acid, B/mal.
3 Instruments and loading
3.1 Sulfur determination device See Figure 1:
1-Oxygen cylinder 12-Oxygen pressure gauge + 3-Flowmeter = 4-Warm flushing bottle 15-Gas washing bottle, containing chromic acid and sulfuric acid 6-Drying tower, containing soda lime or sodium hydroxide (granular), 7-Gas washing bottle, containing sulfuric acid (μ 1.84 8/mL); 18-Drying tower, containing shoe glue and activated alumina; 9-Two-way piston; 10-High temperature comfort furnace (about 800 mm long); 11-Automatic temperature control group (with thermoelectric generator), controlling the furnace temperature at 1400 ~ 1450℃: 12-High temperature combustion tube 13-Energy boat; 11-Silica gel plug 15-Drying tube; 16-Absorption bottle (without floating beads); 17-Reference solution, 18-Volume burette
3. 2 Absorption bottle as shown in Figure 2;
4 Sample
The sample should all pass through a 0.125mm sieve.
5 Analysis steps
5.1 Sample record
Weigh 0.5000g of sample.
5.2 Blank test
GE 47 01. 11 8 8
Perform a blank test on the porcelain boat (2.3) pre-coated with 1g of high-purity iron (2.4) according to 5.3. 5.3 Determination
5.3.1 Connect the various parts of the sulfur determination device and check the airtightness, and heat the high-temperature combustion tube (12) to raise the temperature inside the tube to 1400~1450℃. 5.3.2 Transfer 40mL of absorption liquid (2.8) to the absorption bottle (16), add 5 drops of mixed indicator (2.9), and pass oxygen at a flow rate of 700~900mL/min for about 5min to drive out the carbon dioxide in the solution. If the solution is reddish purple at this time, add sodium hydroxide standard solution (2.11) until the solution is full of green.
5.3.3 Place the sample 5.1) in the porcelain boat (2.3), cover it with B high purity iron (2.4), and 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 burn the sample for 5 mln, 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 (2.11) until the solution changes from red-purple to bright green. Then, pass oxygen at a flow rate of 1000~1200 mL/min, controlled by the two-way piston (9) for 5 min. If the solution is red-purple, continue to titrate with sodium hydroxide standard solution (2.11) until it turns bright green. Stop passing oxygen, and then use the above absorption liquid to wash the drying tube GB 4701.11-88
(15) and the pipes at the connecting parts, and introduce it into the absorption bottle. If the solution is red-purple, continue to titrate with sodium hydroxide standard solution (2.11) until it turns bright green.
6 Calculation of analysis results
Calculate the percentage of sulfur according to formula (2):
s(%)--F):ex0.01603
Wherein, V,-
7 Allowable difference
The volume of sodium hydrofluoride standard solution consumed when titrating the sample solution, mL; The volume of sodium hydroxide standard solution consumed when titrating the blank test solution, mL; The maximum concentration of the substance in the sodium hydroxide standard solution, mol/L; Sample plate, 81
-1.00mL1.000mot/LThe molar mass of sulfur equivalent to the sodium hydroxide standard solution, g/mol. The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table. Sulfur
>0. 006 -~ 0. 015
>0. 015~ 0. 025
>0. 025 ~0. 045
>0. 046~0. 070
Additional remarks:
This standard was drafted by Hunan Ferroalloy Factory.
The main drafters of this standard are Zhang Yulan and Yin Dajian.
From the date of implementation of this standard, the Ministry of Metallurgical Industry Standard YB581-65 "Chemical Analysis Method of Ferrotitanium" will be invalidated. The level mark of this standard is GB4701.11-88I (2)
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