This standard is applicable to the determination of sulfur content in ferromolybdenum. GB/T 5059.10-1988 Chemical analysis of ferromolybdenum - Determination of sulfur content by potassium iodate titration method for combustion GB/T5059.10-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical anatysis of ferronymdium
Determining sulfur content by potassium iodate titration
Methods for chemical anatysis of ferronymdium The combustion-potassium iodate titratlon method for thedetermining sulfur content in ferronymdium This standard is applicable to the determination of sulfur content in ferronymdium. Determination range: 0.015%~0.250%. UDC 669.15'28
GB 5059. 10
This standard complies with CB1467-78 "General Principles and General Provisions for Chemical Analysis Methods of 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 a hydrochloric acid absorption blanket, and a starch solution containing potassium iodide is used as an indicator and titrated with a potassium iodate standard solution. 2 Reagents and Materials
The water used in this standard is 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 overflow combustion tube: Φ×L, mm: 20~24×600. 2.3 Porcelain plate: pre-burned in a high-temperature combustion tube at 1400 for 5 minutes with oxygen, cooled and used. 2.4 High-purity iron: powdered, sulfur content less than 0.001 0%. 2.5 Vanadium pentoxide, powdered, content less than 0.001 0%. 2.6 Silica gel, activated alumina or perchloric acid bond. 2.7 Soda lime or hydroxide (granular).
2.8 Chromic acid saturated sulfuric acid: add potassium dichromate or chromic anhydride to sulfuric acid (p1.84 g/mL) to make it simmer, and use the upper part to avoid clear solution.
2.9 Starch solution: weigh 1.0g of starch into a 300mL beaker, add about 5mL of water, and adjust. Add about 50mL of boiling water, stir constantly, boil on an electric stove for about 1min, remove and cool. Take another 1.5g of potassium iodide and dissolve it in 10mL of water, add this solution to the starch solution, dilute with water to 100mL, and mix well. 2.10 Collection liquid or reference solution: transfer 60mL of hydrochloric acid (1.5+98.5), add 2mL of starch solution (2.9), 2~3 drops of potassium iodate standard solution (2.11), and make the falling liquid light blue. Prepare two bottles of this solution when using, one of which is used as the absorption liquid during determination, and the other is used as the reference liquid for judging the titration end point.
2.11 Potassium iodate standard solution
2.11.1 Preparation
Weigh 0.2225g potassium iodate standard reagent, 1g potassium iodide and 0.10g sodium hydroxide and dissolve them in water, dilute to 1000mL and mix.
2.11.2 Calibration
Weigh 0.5000g of a standard sample with a known content similar to the sample composition and perform the test according to 5.3. 2.11.3 Blank testwwW.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 5059.10—88
Perform a blank test on a porcelain boat (2.3) pre-filled with 1g of high-purity iron (2.4) and 0.25g of vanadium oxide (2.5) according to 5.3, and take the average value for basic evaluation.
Calculate the sulfur titration of potassium iodate standard solution according to formula (1): T
Wherein:
(= V)× 100
-Titer of potassium iodate standard solution for sulfur, g/mL; sample, 81
Sulfur content of standard sample, %:
Volume of potassium iodate standard solution consumed in titration standard test, mL; ki
Volume of potassium iodate standard solution consumed in titration blank test, mL, V. -
3 Instruments and devices
3.1 Sulfur titration device See Figure 1,
1—Oxygen cylinder, 2--Oxygen pressure gauge; 3—Flowmeter; 4—Flush bottle 1 5—gas washing bottle, containing chromic acid and saturated sulfuric acid; 6—drying tower, containing soda lime or sodium hydroxide (granular); 7—gas washing bottle, containing alkaline acid (p1.84g/mL); 8—coal drying tower, containing silica gel and activated alumina; 9—two-way piston; 10—high temperature combustion (about 300mm long); 11—automatic overflow controller (with thermoelectric regulator), controlling the furnace temperature at 1400~1450℃; 112 high temperature combustion tube; 13—porcelain boat + 14—rubber plug; 15—dehydrating tube (containing degreasing trap); 16—absorption bottle (without floating beads); 17 reference storage; 18—micro burette 3.2 Absorption bottle See Figure 2:
4 Sample
The sample should all pass through the 0.125mm sieve.
5 Analysis steps
5.1 Sample quantity
Weigh 0.5000g sample.
5.2 Blank test
Carry out a blank test according to 2.11.3.
5.3 Determination
GB 5059.10-88
5.3.1 Connect the sulfur-fixing device and all parts, and check the airtightness. Heat the high-temperature combustion tube (12) to raise the temperature inside the tube to 1400~1450. Transfer 40mL of the absorption liquid (2.10) into the absorption bottle (16). 5.3.2 Transfer the sample (5.1) into the porcelain boat (2.3) pre-filled with high-purity liquid (2.4), cover it with 0.25g of monocalcium pentoxide (2.5), push it into the high-temperature part of the center of the high-temperature combustion tube (12), tighten the silica gel (11) (special seal), and slowly pass oxygen to prevent the absorption liquid from reflux.
5. 3.3 Pass oxygen through the flow hood at a rate of about 600 mL/min to burn the sample, and introduce the generated sulfur dioxide into the collection bottle (16). While comparing with the reference solution (2.10), titrate with potassium iodate standard solution (2.11.2) until the test solution and the reference solution have the same light blue color, which is the end point. Then, pass oxygen through the two-way piston (9) at an oxygen flow rate of 900~1 000 ml/min for 3 minutes. If the absorption solution fades, continue to titrate with potassium iodate standard solution (2.11.2) to the end point.
Calculation of analysis results
Calculate the percentage of sulfur according to formula (2): GB 5059.10-88
S(%)=A,-X×T
-The volume of iodic acid standard solution consumed in titration of the sample, mL; or
I--The volume of potassium iodate standard solution consumed in titration of blank test, mLtThe titer of potassium iodate standard solution on sulfur, g/mLtT
-Sample sample, g.
7 Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table. Bowl
0.015-~0.025
>0. 025~~0. 045
>0. 045 ~ 0. 070
*0. 070~0. 120
>0. 1200. 250
Additional remarks:
This standard was drafted by Hunan Ferroalloy Factory.
The main drafters of this standard are Zhang Yulan and Kaidajian. Allowance
From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB580:65 "Chemical Analysis Method of Ferromolybdenum" will be invalid. GB 5059. 10. 88 1
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