This standard specifies the determination of sulfur content in nickel-chromium and nickel-chromium-iron alloys by combustion-potassium iodate titration. This standard is applicable to the determination of sulfur content in nickel-chromium and nickel-chromium-iron alloys. Determination range: 0.003% to 0.025%. JB/T 6326.11-1992 Chemical analysis method for nickel-chromium and nickel-chromium-iron alloys Determination of sulfur content by combustion-potassium iodate titration JB/T6326.11-1992 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Chemical Analysis Method of Chromium and Nickel-Chromium-Iron Alloy
Determination of Sulfur Content by Combustion Potassium Iodide Titration
1 Subject Content and Scope of Application
This standard specifies the determination of sulfur content in nickel-chromium and nickel-chromium-iron alloys by combustion potassium iodate titration. JB/T
This standard is applicable to the determination of sulfur content in nickel-chromium and nickel-chromium-iron alloys. Determination range: 0.003% to 0.025%. 2 Reference Standards
GB1467 General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products 3 Summary of Methods
The sample is burned in a high-temperature furnace with oxygen, and the generated sulfur dioxide is absorbed by starch-potassium iodide solution and then titrated with potassium iodate standard solution. 4 Reagents and Instruments
4.1 Anhydrous Calcium Fluoride.
4.2 Potassium Iodide.
4.3 Sodium Hydroxide.
Alkali Asbestos.
Flux: tin granules + reduced iron powder (1+1). 4.6·Glass wool.
Sulfuric acid (density p1.84g/ml).
Hydrochloric acid (1+99). www.bzxz.net
Starch-potassium iodide absorption solution, weigh 9g starch, mix it into a paste with a small amount of water, add 500ml boiling water, stir, boil and dissolve, 4.9
Cool, add 15g potassium iodide, 500ml water, mix well. ·4.10 Preparation and calibration of potassium iodate standard solution. 4.10.1 Weigh 0.2225g potassium iodate (4.2) and dissolve it in water, add 1g sodium hydroxide (4.3), stir and dissolve, transfer to a 1000ml volumetric flask, dilute to the mark with water, and mix well. This is the stock solution. 4.10.2 Take 50 ml of potassium iodate standard solution (4.10.1) in a 1000 ml volumetric flask, dilute to scale with water, and mix well. 4.10.3 Calibration of potassium iodate standard solution: Weigh three standard samples with similar content to the test sample in triplicate, and calibrate according to the analytical steps. Calculate the titer of potassium iodate standard solution according to the following formula. cm
VV×100
Wherein: T-titration degree of potassium iodate standard solution on sulfur, g/mlC-percentage of sulfur in standard sample;
Sample volume, g:
Average volume of potassium iodate standard solution consumed when titrating standard sample, ml; Approved by the Ministry of Machinery and Electronics Industry on June 26, 1992, 26
Implementation on January 1, 1993
JB/T6326.11-92
Average volume of potassium iodate standard solution consumed when titrating blank test, ml; See the figure for instruments and devices.
Diagram of instruments and devices for determining sulfur
1—oxygen cylinder, 2—oxygen meter; 3—buffer bottle; 4—gas washing bottle; containing one-third volume of sulfuric acid (4.7); 5—gas purification tower, with alkali asbestos (4.4) on the upper layer and anhydrous calcium chloride (4.1) on the lower layer, glass wool (4.6) in the middle, and glass wool at the bottom and top. 6—tube guard,
9—low sulfur absorption cup;
7 automatic temperature controller,
8 flow meter:
11—porcelain tube, 600mm long, 23mm inner diameter
10 burette, 25ml;
12 porcelain boat, 88mm; 97mm
Analysis steps
5.1 Sample quantity
Weigh 1.000g of sample.
5.2 Blank test
Carry out a blank test together with the sample.
5.3 Determination
5.3.1 Raise the furnace temperature to 1250~1300℃. 13-spherical drying tube, filled with absorbent cotton. 5.3.2 Add 50-70ml hydrochloric acid (4.8) and 2ml starch-potassium iodide solution (4.9) to the low-sulfur absorption cup, and pass oxygen (flow rate is 1.0~1.5L/min). Titrate with potassium iodate standard solution (4.10.2) until it turns light blue, and turn off the oxygen. 5.3.3 Place the sample in a porcelain boat that has been pre-burned with oxygen at 1200℃, evenly spread 2g of flux (4.5) on the sample, put the porcelain boat containing the sample into the porcelain tube, and push the porcelain boat to the highest temperature in the furnace with a long hook of nickel-chromium wire. Immediately plug the rubber stopper, preheat for about 1 minute, pass oxygen (flow rate 1.0 ~ 1.5L/min), and pass the combustion gas into the low-sulfur absorption cup. When the light blue color in the absorption cup begins to fade, immediately titrate with potassium iodate standard solution (4.10.2) to keep the absorption solution surface blue. When the absorption solution fades slowly, the titration speed should also be reduced until the color of the absorption solution returns to its original color. 5.3.4 Turn off the oxygen, open the rubber stopper, pull out the porcelain boat with a long hook, and read the volume ml of potassium iodate standard solution consumed in the titration. 6
Calculation of analysis results
Calculate the percentage of sulfur according to the following formula:
s (%) =T: =V)×100
Titer of potassium iodate standard solution on slag. g/ml; where: T
-volume of potassium iodate standard solution consumed by titration sample, ml; y
-volume of potassium iodate standard solution consumed by blank test, ml; sample size, g.
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