This standard is applicable to the determination of silicon content in ferrosilicon. Determination range: 30.00-98.00%. This standard complies with GB 1467-78 "General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products". GB 4333.1-1984 Chemical Analysis Method for Ferrosilicon Determination of Silicon Content by Perchloric Acid Dehydration Gravimetric Method GB4333.1-1984 Standard Download Decompression Password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical analysis of ferrosiliconThe perchloric acid dehydration-gravimetricmethod for the determination of silicon contentThis standard applies to the determination of silicon content in ferrosilicon. Determination range: 30.00～98.00%. This standard complies with GB1467-78 "General Principles and General Provisions of Standards for Chemical Analysis Methods of Metallurgical Products". 1 Summary of Methods
UDC 669.15' 782
: 543.21 :546
GB 4333.1--84
The sample is melted with a sodium carbonate-sodium peroxide mixed flux to convert silicon into silicate, acidified with hydrochloric acid, and dehydrated with silicate by secondary fuming with perchloric acid. After filtering and washing, the precipitate is burned at 1050-1100℃ to constant weight, hydrofluoric acid is added to volatilize silicon tetrafluoride, and then burned to constant weight. The percentage of silicon is calculated from the mass difference before and after hydrofluoric acid treatment. 2 Reagents
2.1 Sodium carbonate-sodium peroxide mixed flux: 1 part of anhydrous sodium carbonate and 2 parts of sodium peroxide are mixed and used. 2.2 Hydrochloric acid (specific gravity 1.19). wwW.bzxz.Net
2.3 Hydrochloric acid (1+1).
2.4 Hydrochloric acid (5+95).
2.5 Perchloric acid (specific gravity 1.67).
2.6 Ammonium hydroxide (specific gravity 0.90).
2.7 Hydrofluoric acid (specific gravity 1.15).
2.8 Sulfuric acid (1+1).
2.9 Silver nitrate solution (2%).
3 Sample
The sample should pass through a 120-day sieve.
4 Analysis steps
4.1 Sample quantity
Weigh 0.3000g of sample (when the silicon content of the sample is 50% or less, weigh 0.2000g of sample). 4.2 Blank test
Carry out a blank test with the sample.
4.3 Determination
4.3.1 Place the sample (4.1) in an iron (nickel) crucible that has been pre-filled with 8g of sodium carbonate-sodium peroxide mixed flux (2.1), stir evenly, and then cover with 2g of mixed flux (2.1). Place the crucible on a low-temperature electric heating plate, cover the crucible, heat and bake until the flux is brown, melt it in a high-temperature furnace or blowtorch at 850-900℃ until it is completely melted, continue melting for 2 minutes, and cool. After washing the outer wall with water, place it in a 250ml plastic beaker, add 100ml hot water, cover it with table blood, wait for the reaction to stop, use hot water to clean the crucible and cover with a wiping stick and take out. Slowly transfer the liquid into a 600ml glass beaker containing 35ml hydrochloric acid (2.2), wash the plastic beaker and table III with water, add the washing liquid into the glass beaker, stir until the solution is clear. 4.3.2 Add 80ml perchloric acid (2.5), cover table III with a gap, place on an electric hot plate or low-temperature electric furnace 1, heat until white perchloric acid smoke is emitted (about reflux for 20 minutes), until the residue becomes a paste, remove and cool. Add 20ml hydrochloric acid (2.3) along the wall of the cup, rinse the table and the wall of the cup with a little hot water, add 100ml hot water (80℃ or above), and stir to dissolve the salts. 4.3.3 Filter the solution into a 600ml beaker with medium-speed quantitative filter paper while it is still hot, transfer the precipitate to the filter paper, carefully scrub the glass rod and the wall of the cup with a wiping stick, clean the beaker and the glass rod with hot hydrochloric acid (2.4), wash the precipitate until there is no iron (nickel) ion (about 5 to 6 times), and then wash it with hot water until there is no chloride ion [check with silver nitrate solution (2.9)]. Keep the filter paper and precipitate. 4.3.4 Transfer the filtrate and washing solution into the original beaker, add 20ml perchloric acid (2.5), and proceed as in 4.3.2 and 4.3.3. 4.3.5 Place the two precipitates together with the filter paper (4.3.3, 4.3.4) in a crucible, add 4 drops of ammonium hydroxide (2.6), and bake in an oven at about 150℃ until nearly ten. Carefully heat at 500-600℃ to carbonize the filter paper. Gradually heat until the carbon is completely oxidized, cover it, and place it in a high-temperature furnace at F1100-1150℃ to burn for 30min, take it out, cool it slightly, place it in a desiccator, cool it to room temperature, weigh it, and burn it repeatedly until the constant weight (m,).
4.3.6 Moisten the impure silicon dioxide with a few drops of water, add 4 drops of sulfuric acid (2.8) and 6ml of hydrofluoric acid (2.7), place it on an electric hot plate or low-temperature electric furnace, evaporate it until sulfuric acid fumes appear, cool it slightly, add 4ml of hydrofluoric acid (2.7), and continue heating and evaporating until sulfuric acid fumes disappear. Place the crucible in a 950℃ high temperature furnace and burn for 30 minutes, take it out and place it in a desiccator. Cool to room temperature, weigh it, and burn it repeatedly until the weight is constant (m2).
5 Calculation of analysis results
Calculate the percentage of silicon according to the following formula:
Si (%) =[(ml-m2)-(m=-m)x0.4675 ×100m
Where: mt
The mass of the platinum crucible and precipitate before hydrofluoric acid treatment, g, the mass of platinum and residue after hydrofluoric acid treatment, g, m3--The mass of the blank and platinum crucible with the sample before hydrofluoric acid treatment, g; m4-The mass of the residue and platinum crucible with the sample blank after hydrofluoric acid treatment, g, m -
6 Allowable difference
Sample weight, g,
The conversion factor of silicon dioxide to silicon. %
Additional Notes:
GB 4333.1—84
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by Shanghai Ferroalloy Factory. This standard was drafted by Shanghai Ferroalloy.
The main drafters of this standard are Dong Dafu and Qian Boyuan. From the date of implementation of this standard, the determination of silicon content in the former Ministry of Metallurgical Industry Standard YB72-65 "Chemical Analysis Method of Ferrosilicon" will be invalid. 91
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