GB/T 4333.3-1988 Chemical analysis method for ferrosilicon - Determination of manganese content by potassium periodate photometric method GB/T4333.3-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method for ferrosilicon
Potassium periodate photometric method for determination of manganese content
Mcthods for chemical analysis af ferrosiliconThe potassluru periodnte photometric methodfor tht determination of mangancse contcni1Subject content and scope of application
This standard specifies the potassium periodate photometric method for the determination of manganese content. This standard is applicable to the determination of medium-chain content in ferrosilicon. Determination range: 0.100% to 0.800%. 2 Method Summary
UDC 669.15782
543.42:546
GB 4333.3-88
Replaces GB 4333. 3-$1bzxz.net
Dissolve the sample with nitric acid and hydrofluoric acid, and then oxidize manganese into purple-red permanganate with potassium periodate in a sulfuric acid-phosphoric acid mixed acid medium, and measure its absorbance at a wavelength of 530nm on a spectrophotometer. 3 Reagents
3. 1 Nitric acid (pl 42 g/mL),
3. 2 Hydrofluoric acid (pl. 15 g/mL),
3.3 Sulfuric acid (1-1).
3.4 ​​Sulfuric acid and phosphoric acid mixture: slowly add 500 mL of sulphuric acid (p 1.84 g/ml) to 1000 mL of water. Cool, add 500 mL of phosphoric acid (p 1.70 g/mL) and mix.
3.5 Potassium periodate solution (50 mg/mL) weigh 5 g of potassium periodate, put them in a 250 mL beaker, add 60 mL of water and 15 mL of nitric acid (3.1). Dissolve in warm water, cool, transfer to a 100 mL volumetric flask, dilute to the mark with water, and mix well. 3.6 Sodium nitrite solution (10 mg/mL).
3.7 Manganese standard solution:
3.7.1 Treatment of electrolytic manganese; immerse the electrolytic manganese with sulfuric acid (5+95), heat until the surface manganese oxide dissolves, take it out, rinse it repeatedly with water, then wash it 5 times with anhydrous ethanol, and dry it at room temperature.
3.7.2 Preparation of manganese standard solution:
3.7.2.1 Weigh 5000g of treated electrolytic manganese (99.95% or more) and place it in a 250mL beaker. Add 20mL of sulfuric acid (3.3). Heat at low temperature to dissolve and evaporate to a volume of about 3~5mL. Remove, cool to room temperature, transfer to a 1000mL container bottle, dilute to scale with water, mix, and this solution contains 500μg manganese in 1mL.
3. 7. 2. 2 Transfer 20. 00mL of manganese standard solution (3. 7. 2. 1) and place it in a 100mL volumetric flask. Dilute to scale with water and mix. This solution contains 500μg manganese in 1mL:
4 Sample
The sample should pass through a 0. 125 mm sieve.
Approved by the Ministry of Metallurgical Industry of the People's Republic of China on September 8, 1988 and implemented on January 1, 1990
5 Analysis steps
5.1 Sample quantity
Weigh 0.2000g of sample.
5.2 Blank test
Carry out a blank test with the sample.
5.3 Determination
GB 4333. 388
5.3.1 Place the sample (5.1) in a 100mE sodium hydroxide or polytetrafluoroethylene beaker, add 10mI nitric acid (3.1), add 8~5mL of fluoric acid (3.2) dropwise while shaking until the sample is completely dissolved, add 1mL of sulfuric acid (3.3), heat at low temperature to evaporate until it becomes acidic for 2 minutes, remove and cool. Add 20mL sulfuric acid-phosphoric acid mixture (3.4), heat until the salts are dissolved, remove and transfer to a 200mL conical flask. 5.3.2 Add 10mL potassium periodate solution (3.5), adjust the solution volume to about 60~70mL with water, boil at low temperature for 3min, remove, cool to room temperature, transfer to a 100mL volumetric flask, dilute to scale with water, mix well, this is the color solution. 5.3.3 Transfer part of the color solution to a 2cm colorimetric dish (use a 1cm colorimetric dish when the manganese content is greater than 0.300%). Use the reference solution [add sodium nitrite solution (3.6) to the remaining color solution while shaking until the purple-red color just fades as a reference, and measure its absorbance at a wavelength of 530nm on a spectrophotometer.
5.3.4 Subtract the absorbance of the accompanying sample blank and find the corresponding manganese maximum from the working curve. 5.4 Drawing of the working curve
When the manganese content is less than 0.300%, transfer 0, 2.00, 3.00, 4.00, 5.00, 6.00 mL of manganese standard solution (3.7.2.2); when the manganese content is greater than 0.300%, transfer 0, 1.20, 1.60, 2.00, 2.40, 2.80, 3.20 mL of manganese standard solution (3.7.2.1) and respectively place them in 200 mL conical flasks, add 20 mL of sulfuric acid-phosphoric acid mixture (3.4), and proceed as in 5.3.2 to 5.3.3. The absorbance measured should be subtracted from the absorbance of the reagent blank when drawing the working curve. Draw the working curve with the manganese content as the horizontal axis and the absorbance as the vertical axis. 6 Calculation of analysis results
Calculate the percentage of manganese by the following formula:
4×100
Mn(%)=
Where:
--Manganese content found on the working curve, 8!
nSample volume, 8.
7 Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table. %
0. 100~-0.250
20.3506.350
>0.350~0.550
2-0. 550 -- 0. 800
Additional remarks:
This standard was drafted by Xinyu Iron and Steel Plant, and the main drafters of this standard are Chen Xiuzhen and others. GB4333.3—88
This standard level mark GB4333.3—881
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