GB/T 5686.2-1985 Chemical analysis methods for manganese-silicon alloys - Gravimetric determination of silicon content GB/T5686.2-1985 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis methods of silicomanganese alloy
Gravimetric method for the determination of silicon content
Methods for chelcal analysis of silicomanganese alloy The gravimetric method for the determination of silicon content This standard is applicable to the determination of silicon content in silicomanganese alloy. Determination range: 8.0～30.00%. UDC 669.74° 782
GB 5686.2-85
This standard complies with GB1467-78 "General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products". This standard is equivalent to the international standard IS04158-1978 "Ferrosilicon, ferrosilicomanganese and ferrosilicochrome - Determination of silicon content - Gravimetric method". 1 Summary of the method
The sample is oxidized and melted with sodium peroxide to convert it into silicate, and then extracted with acid. Dehydrate the silicate twice by evaporation in a perchloric acid medium, and weigh the impure silicon dioxide. Volatilize the silicon dioxide twice with hydrofluoric acid-sulfuric acid, weigh the residue, and determine the pure silicon hydride. 2 Reagents
2.1 Sodium peroxide.
2.2 Sodium carboxylate (anhydrous)
2.3 Ammonium hydroxide (n0.90 g/ml)
2.4 Perfluoric acid (p1.61g/ml)*.
2.5 Aminoacid (n1.14g/mD)
2.6 Hydrochloric acid (p1.19g/ml).
Hydrochloric acid (1-9).
2.8 Sulfuric acid (p1.84/m1).
2.9 Sulfuric acid (1+1).
2.10 Silver nitrate solution (1%).
s Apparatus
3.1 Exhaust, weighing 40 ml, iron crucible, nickel crucible or zirconium scale free. 3.2 Beaker, for dissolving melt, made of polyethylene, stainless steel or high purity nickel. 8.3 Platinum, volume 40 ml.
3.4 ​​Glass funnel with ribbed structure, left diameter 75 mm. 4 Sample
The sample should pass through a 0.125 mm sieve.
5 Analysis steps
*When heating the molten acid to smoke, care should be taken to prevent danger. National Bureau of Standards 1985-12-04
1986-10-01
5.1 Sample
Weigh 1.0000 g of sample.
5.2 Blank test
Carry out a blank test with the sample.
5.3 Determination
GB5686.2-85
5.3.1 Place the sample (5.1) in a glass (3.1) containing 10~12g of sodium peroxide (2.1), mix carefully, and cover with 3g of sodium peroxide (2.1) or 3g of sodium carbonate (2.2) to prevent sample loss. Place the sample and flux on a 350~400℃ electric hot plate, heat the whole melt until it turns black, use a crucible stacker to clamp the crucible and rotate it on the flame. To avoid deflagration, heat it slowly first, then heat it strongly until it is completely melted, and keep the molten product in a red-hot state for 5 minutes, then cool the crucible. 5.3.2 Place the crucible in a beaker (3.2) containing 200 ml of water, cover with a lid, wait until there are no bubbles, take out the crucible and wash it with hot water, collect the washing liquid in the same beaker, transfer the alkaline solution into a 600 ml beaker containing 30 ml of hydrochloric acid (2.6), stir the solution, and add 100 ml of pernitrogen acid (2.4) after the salts are dissolved.
5.3.3 Place the beaker on a high-temperature electric hot plate until perchloric acid fumes are emitted, continue heating until the fuming residue begins to crystallize and becomes viscous, remove and cool, slowly add 20 ml of hydrochloric acid (2.6) and a few milliliters of hot water along the inner wall of the beaker to soak, stir and dilute with 250 ml of boiling water, stir well and let stand.
5.3.4 Filter the silica onto a 12.5 cm ordinary quantitative filter paper in a grooved glass funnel (3.4). Keep the filtrate, wipe the beaker with a rag and warm water, wash the filter paper with warm hydrochloric acid (2.7) until there is no yellow color of iron salt, and finally wash it several times with hot water until there is no ammonium ion [check with silver nitrate solution (2.10) for drip test]. The filter paper must be thoroughly washed to remove the traces of perchloric acid that can cause combustion when burned.
Transfer the filtrate and washing solution to the beaker used for initial dehydration. Add 20ml of perchloric acid (2.4), and then carry out the second dehydration and leaching according to Section 5.3.3. Filter and wash the precipitate with new filter paper according to Section 5.3.4, but use cold water instead of hot water for the final wash.
5.3.5 Place the two filter papers containing the silica precipitate in the platinum blood (3.3). Add 4 drops of ammonium hydroxide (2.3) to the filter paper E*. Initially dry and burn in a high temperature furnace not exceeding 400°C. Allow to cool. Add 1 ml sulfuric acid (2,9) and evaporate to dryness without sulfuric acid smoke, then burn at 1100°C to constant weight, cool in a desiccator, and weigh the plate containing impure silicon dioxide. 5.3.6 Wet the impure silicon monocyanide with a few drops of water. Add about 10 ml hydrofluoric acid (2.5) and 2 to 3 drops of sulfuric acid (2.8), evaporate to below, and no sulfuric acid smoke is released. Carry out a second evaporation under the same conditions, but use 2 ml hydrofluoric acid. Burn in a high temperature furnace at 1100°C to constant weight, cool in a desiccator, and weigh the platinum blood containing impurities. 6 Calculation of analysis results
Calculate the percentage of silicon by the following formula:
si (%) --onm=m2 (mm) x0.4674 x100mowww.bzxz.net
Wherein: m——the mass of impure silicon monoxide and platinum measured in 5.3.5, gm2——the mass of impurities and platinum measured in 5.3.6, gsm3——the mass of impure silicon monoxide and platinum measured in the blank test, g1m——the mass of impurities and platinum measured in the blank test, g; m. Sample volume, g!
0.4674——the conversion factor of silicon dioxide to silicon. 7 Tolerance
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table. In order to reduce the risk of silicon dioxide being removed from platinum when perchlorate volatilizes. Additional Notes:
B ~ 15
15 ~ 30
GB5686.285
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by Nanjing Ferroalloys.
From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB79-65 "Chemical Analysis Method of Silicon Manganese Alloy" will be invalid.%
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