GB/T 4699.1-1984 Chemical analysis methods for silicon-chromium alloys - Gravimetric determination of silicon content GB/T4699.1-1984 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical analysis of silicochromiumThe gravimetric method for the determinationof silicon content
Not applicable to the determination of silicon content in chromium alloys. Determination range: 8.00～9500. UDC66982
:5/ 26 543.21
GR 4699.1
ES04158-1978
This standard is equivalent to the general principles and general provisions of the international standard [S01158--1978 "Silicon, ferrochromium-Determination of silicon content-Gravimetric method" and [S01158--1978 "General principles and general provisions of the standard for chemical analysis of metallurgical products"]. Method summary
Oxidize the sample with sodium peroxide to make it melt, convert it into corona salt, incubate it with gastric acid, evaporate it in perchloric acid medium, dehydrate the corona salt twice, weigh its non-oxidized content. Reagents
2.1 Sodium peroxide,
2.2 Sodium carbonate (anhydrous).
Ammonium hydroxide (specific gravity 0.90)
Perchloric acid (specific gravity 1.673).
Oxyfluoric acid (specific gravity 1.15).
Acid (specific gravity 1.19). Www.bzxZ.net
Hydrochloric acid (1+9)
Sulfuric acid (specific gravity 1.84).
Xuanwu (１１)
2.10Silver nitrate solution (1%)
3.1 ml, silicon-free iron crucible, nickel or.3 .2 Melt is burned, polyolefin, stainless steel is changed to high nickel 3.3, volume ml
3.4 Glass with grooves is smooth,
diameter 75mm
3.5 Glass is burned, volume GU1ml or 800ml. 3.6 High temperature mixing furnace
dryer.
When the perchloric acid is slightly excited, the amount of juice is always reduced. National Bureau of Standards 1984-10-04
1985 0901 implementation
The sample should pass through a 0.125mm sieve.
5 Analysis steps
5.1 Sample size
GB 4699.1-84
Silicon content is less than or equal to 50%, weigh 0.5000g of sample. Silicon content is less than 25%, weigh 1.000g of sample. Silicon content is greater than 50%, weigh 0.2500g of sample. 5.2 Blank test
Carry out a blank test with the sample.
5.3 Determination
5.3.1 Place the sample (5.1) in a glass (3. 1) Mix carefully. To prevent loss of sample, cover with 3 g sodium peroxide (2.1) or 3 g sodium carbonate (2.2). Place the crucible containing sample and flux on a 350-400℃ electric heating plate and heat until the molten material turns black. Hold the crucible with crucible tongs and rotate it over the flame. To avoid explosion, heat slowly first, then heat strongly until it is completely melted, and keep the molten product red hot for about 5 minutes. Cool the crucible. 5.3.2 Place the crucible in a beaker containing 200 ml water ( 3.2) towel, cover with a tableware, wait until no bubbles appear, take out the diseased, wash with hot water, collect the washing liquid and add it to the same beaker, transfer the alkaline solution to the beaker (3.5) containing 30ml hydrochloric acid (2.6), stir the solution, wait for the salt to dissolve, and add 100ml perchloric acid (2.4). 5.3.3 Place the beaker on a high temperature electric heating plate until the perfluoric acid smoke is generated, continue heating until the residual flow of smoke begins to form and becomes viscous, remove and cool, and slowly add 20ml of perfluoric acid along the inner wall of the beaker. l Hydrochloric acid (2.6) is diluted with 1 ml of hot water, stirred and diluted with 250 ml of boiling water, stirred and condensed.
5.3.4 Filter the carbon dioxide through a grooved glass funnel (3.4) on ordinary fixed filter paper. Keep the filtrate and wipe the beaker with a wipe and wet water. Wash the filter paper with warm hydrochloric acid (2.7) until there is no yellow color of iron and chromium salts, and finally wash it several times with hot water until there is no chlorine ion [check with silver nitrate solution (2.10) for drip test]. The filter paper must be thoroughly washed to remove traces of perchloric acid that can cause combustion when burned.
Transfer the filtrate and washing liquid to the beaker used for the initial dehydration. Evaporate to about 250 ml. Add 20 ml of perfluorinated aldehyde. (2.4), and then carry out the second dehydration and extraction according to 5.3.3. Filter and wash the precipitate with new filter paper as in 5.3.4, but use cold water instead of hot water for the final wash.
5.3.3 Place the two filter papers containing the silica precipitate in the platinum solution (3.3). Add 4 drops of ammonium hydroxide (2.3) on the filter paper*, initially dry and burn in a high temperature furnace (3.6) not exceeding 400°C. Allow to cool. Add 1m sulfuric acid (2.9), simmer to ten, no sulfuric acid fumes are emitted, then burn to constant weight at 1100°C, cool in a desiccator, and weigh the pot containing the impure silica. 5.3.6 Moisten the impure silicon monoxide with a few drops of water. Add about 10 ml of hydrofluoric acid (2.5) and 2 to 3 drops of sulfuric acid (2.8), evaporate to ten, and no sulfuric acid fumes are emitted. Perform the second evaporation under the same conditions, but use 2 ml of hydrofluoric acid. Burn in a high temperature furnace (3.6) at 1100℃ until the weight is constant, cool in a desiccator, and weigh the platinum dish containing impurities. 6
Calculation of analysis results
Calculate the silicon content according to the following formula:
S; (3) =
((mj-m2))-(mg-m))×D.4674o
The mass of impure monoxide and platinum blood measured in 5.3.5, g: In the formula:
, this is for the danger of alkali-free perchlorate volatilizing to produce less sensitive silicon oxide in the heat. ×100
GB 4699,1-8±
—5,3. The mass of the impurities measured in the blank test is the mass of the impurities measured in the blank test and the mass of the impurities measured in the blank test. gm
The mass of the impurities measured in the blank test and the mass of the platinum III is the mass of the sample, g
0.4674—
Allowable difference
The conversion factor for silicon dioxide conversion is the conversion factor. The values ​​of the experimental cases are not allowed to collide with each other. The following table lists the values. 50.00
Additional remarks:
This international standard is issued by the Ministry of Industry of the People's Republic of China. The Shanghai Ferroalloy Factory is responsible for the implementation of this standard. From the implementation of this standard, the original Ministry of Industry Standard YH577-65 "Methods for Chemical Analysis of Alloys" will be invalid.
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