GB/T 3653.3-1988 Chemical analysis method for ferroboron - Determination of silicon content by gravimetric method with perchloric acid dehydration GB/T3653.3-1988 standard download decompression password: www.bzxz.net

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Methods for chemical analysis ot ferroboronThe perchlnric acid dehydration-gravimetric methodfor ihe deletmination ot sllicon content1Subject content and scope of application
This method specifies the determination of silicon content by perchloric acid dehydration-gravimetric method. This standard is applicable to the determination of silicon content in ferroboron, with a determination range of 0.50% to 16.00%. 2 Method Summary
UDC 669. 15' 781
GE3653.3—88
Replace G 3653.3-83
The sample is dissolved with acid, the insoluble residue is filtered and burned, and melted with sodium carbonate and sodium peroxide as flux, leached with dilute hydrochloric acid, evaporated to a small volume, perchloric acid fume is added to condense the silicic acid, filtered and burned, the boron is evaporated with methanol, burned to constant weight, the silicon is removed with hydrofluoric acid, burned to constant weight, and the percentage of silicon is calculated.
3 Reagents
3.1 Sodium carbonate, anhydrous.
3.2 Sodium peroxide.
3.3 Hydrochloric acid (gl.19g/mL).
3.4 ​​Hydrochloric acid (5-95).
3.5 Nitric acid (pl.42 g/mL)
3. 6 Perchloric acid (pl1. 67 g/mL),
3. 7 Hydrofluoric acid (p1. 15 g/rmL).
3.8 Methanol.
3.9 Sulfuric acid (1+1).
3.10 Ammonium thiocyanate solution (5 mg/mL).
3.11 Silver nitrate solution (10 mg/mL).
4 Sample
The sample should not pass through a 0.088 mm sieve.
5 Analysis steps
5.1 Sample quantity
Weigh 0.500~1.000g of sample (when the silicon content of the sample is 0.50%~1.00%, take 1.000g; when the silicon content of the sample is 1.00%~16.00%, weigh 0.500g).
Approved by the Ministry of Metallurgical Industry of the People's Republic of China on September 8, 1988 and implemented on January 1, 1990
5.2 Concave test
Carry out a blank test together with the sample.
5.3 Sputtering
GB3653.388
5.3.1 Place the sample (5.1) in a 400-mL beaker, add 31 mL of hydrochloric acid (3.3) and 10 mL of nitric acid (3.5), and heat on a hot plate until the sample is completely dissolved. If the sample cannot be completely dissolved in the acid, it should be treated as follows: filter it with rapid quantitative filter paper in a 300mL beaker, wipe off the residue on the wall of the beaker with a wiper, wash the beaker with hot water, and wash the precipitate 3-5 times, save the filtrate, put the filter paper precipitate in a nickel crucible, bake it, carefully carbonize it, burn it to ashes, take it out and cool it slightly, add 1 part sodium carbonate (3.1) and 18 part sodium peroxide (3.2), stir it with a spoon, melt it in a high-temperature furnace at 850℃ for 5-8 minutes (operate at any time), take it out and cool it into the original beaker, pour the saved filtrate into the original beaker, wash the beaker, wait for the molten material to dissolve, wash it with hot water, take it out, add 10mL hydrochloric acid (3), heat it to a volume of 30-40 mL5.3.2 Add 30mL of pernitrogen acid (3.6), add Table IIIL, place on a hot plate, heat until thick perchloric acid smoke appears at the mouth of the cup, reflux, keep for 20 minutes, remove and cool, add 10mL of hydrochloric acid (3.3) and 100mL of hot water (above 80°C), heat to dissolve the salts, remove 5.3.3 Filter with medium-speed quantitative filter paper, wash the beaker, wash with acid (3.4) to precipitate iron ions [check with ammonium thiourea solution (3.10)]. Then wash with hot water until there is no chloride ion [check with silver nitrate solution (3.11)]. 5.3.4 Repeat the filtrate according to 5.3.2 and 5.3.3. 5.3.5 Place the two precipitates together with the filter paper in a platinum vortex, dry for ten minutes, carefully burn to ashes, and burn in a high-temperature furnace at 1000°C for 20 minutes. 5.3.6 Take it out, cool it down a little, add 5L of medium alcohol (3.8), evaporate it carefully on a low-overflow electric furnace, and then burn it in a high-temperature furnace at 1000℃ for 30min. Take it out and put it in a desiccator, cool it to room temperature, weigh it and burn it repeatedly until it reaches a constant weight (ml). 5.3.7 Moisten the impure silicon dioxide with water, add 8 drops of sulfuric acid (3.9) and 5mL of hydrofluoric acid (3.7) on a hot plate, heat it carefully to evaporate until the white smoke of sulfur trioxide disappears, place it in a high-temperature furnace at 1000℃ and burn it for 20min. Take it out, put it in a desiccator, cool it to room temperature, weigh it and burn it repeatedly until it reaches a constant weight (mz).
6 Calculation of analysis results
Calculate the percentage of silicon by the following formula:
si(%) = ((m1 - m) - (m,= m) × 0.467 4 mass of silicon dioxide and platinum, &;
where: ni
mass of residue and platinum,;
m3——mass of blank and platinum crucible accompanying the sample, B; tt||——mass of blank residue and platinum crucible; m—-sample weight-g;
0.4674—conversion factor of silicon dioxide to silicon. 7 Allowable difference
The difference in analysis results between laboratories should not be less than the allowable difference listed in the following table. Additional notes:
0.5U~~1.00
1.00-2.00
>2.00~.5. 00
5. 00~8. 00
>8. 00~-16. 00
This standard was drafted by Qiqihar Steel. The main drafters of this standard are Fan Lixiang and others.
GB3653. 3—88
The horizontal grade mark of this standard is GB3653.3-881.
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