JB/T 9220.2-1999 JB/T 9220.2-1999 Chemical analysis of acidic slag from foundry cupola - Determination of silicon dioxide by gravimetric method with perchloric acid dehydration JB/T9220.2-1999 Standard download decompression password: www.bzxz.net

JB/T9220.2
Determination of Oxidation by Perfluoric Acid Dehydration Gravimetric Method
This standard is a revision of JB/Z284.2-87 "Silicon Content in Acidic Slag of Casting Cupola Furnaces". During the revision, editorial changes were made to the original standard, and the main technical content remained unchanged. This standard replaces J13/Z284.2-87 from the date of implementation. This standard was proposed by the National Technical Committee for Foundry Standardization and is under the jurisdiction of the drafting units of this standard: Shanghai Diesel Engine Factory, Nanchang Diesel Engine Factory, Guiyang Foundry, Shenyang Foundry, Shanghai Tractor Company, Huafeng Steel, Wuxi Diesel Engine, Changzhou Diesel Engine, etc. The main drafters of this standard: Wang Zhihan, etc. 426
1 Scope
Standard of the Machinery Industry of the People's Republic of China
Chemical analysis methods for acid slay of cupola-Determination of silica by gravimetrice methodusing perchloric acid dewateringJB/T 9220.2
Replaces JB/Z281.2:-87
This standard specifies the determination of silica content in chemical analysis methods. Determination range: 35.00%~60.00%. This standard is applicable to the analysis of the composition of acid slag of cupola-casting furnace. 2 Test conditions
The sample is dissolved in alkali, leached with hydrochloric acid, and silicon is converted into silicic acid. The silicic acid is dehydrated by evaporating and smoking with perchloric acid, filtered and washed, and then burned into silicon dioxide. In the presence of sulfuric acid, it is treated with hydrofluoric acid to generate silicon tetrafluoride from silicon dioxide and volatilize and remove. Calculate the percentage of silicon dioxide from the mass difference before and after silicon removal.
3 Reagent preparation
3.1 Anhydrous sodium carbonate.
3.2 Mixture: Mix 2 parts of anhydrous sodium carbonate (3.1) with 1 part of sodium tetraborate. 3.3 Hydrochloric acid (density 1.19 g/ml).
3.4 ​​Hydrochloric acid (1+1).
Hydrochloric acid (5+95).
Perchloric acid (density 1.67 g/ml).
3.7 Ammonium thiocyanate solution: (5%).
Silver nitrate solution: (1%).
3.9 Anhydrous ethanol.
Sulfuric acid (density 1.84 g/mL).
Hydrofluoric acid (density 1.15 g/mL).
4 Analysis steps
4.1 Sample quantity
Weigh 0.5000g sample.
4.2 Blank test
Perform blank test with the sample
4.3 Determination
4.3.1 Place the sample (4.1) in a 30mL platinum crucible, add 5g mixed solvent (3.2), stir, cover, and bake on a hot plate at low temperature Approved by the State Bureau of Machinery Industry on June 24, 1999 and implemented on January 1, 2000
JB/T 9220.2 --1999
After a while, place the platinum crucible in a high-temperature furnace at 950℃ and melt it for 10-15min. Note: When the sample does not contain fluorine, 5g of anhydrous sodium carbonate (3.1) can be directly added to melt it. 4.3.2 Take it out and cool it. Put it in porcelain evaporator III and soak it with 10ml of hot hydrochloric acid (3.3). When the melt is dissolved, wash the platinum crucible and the crucible cover with hot water, add 30ml of perchloric acid (3.6), heat it slightly until the melt is completely dissolved, and then heat it until white perchloric acid smoke comes out. Cover it with table III and continue heating to reflux the perchloric acid for about 10min.
4.3.3 Remove and cool slightly, add 50mL hot water, stir, and heat again (but do not boil) to dissolve soluble salts, filter with medium-speed quantitative filter paper and a small amount of quantitative filter paper pulp, carefully wipe off the precipitate adhering to the wall with a wiper, wash the evaporator and filter paper with hot hydrochloric acid (3.5), and wash the precipitate and filter paper until there is no iron ion [check with ammonium thiocyanate solution (3.7)], and then wash with hot water until there is no chloride ion [check with silver nitrate solution (3.8)].
4.3.4 Transfer the filtrate and washing liquid into the original evaporator, heat and concentrate until white perchloric acid smoke is emitted, cover with a filter, and reflux for 100 minutes, and then filter and wash according to 4.3.3.
4.3.5 Place the precipitate obtained twice together with the filter paper and pulp in a platinum crucible, dry, ash, cover part of the amber with a platinum pot lid, and burn in a high-temperature furnace at 950°C for 15~20min. 4.3.6 Take it out and cool it slightly, add 1ml hydrochloric acid (3.3) and 1ml anhydrous ethanol (3.9), evaporate carefully on a hot plate at low temperature, repeat times, and then burn in a high-temperature furnace at 950°C for 10min, take it out and cool it slightly, place it in a desiccator, weigh it after cooling to room temperature, and repeat the burning until constant weight: Note: When the sample does not contain fluorine, use anhydrous sodium carbonate to melt it, and the boron removal step of adding hydrochloric acid and ethanol can be omitted. 4.3.7 Add water to moisten the precipitate along the inner wall of the glass, add 2 drops of sulfuric acid (3.10), 3 ml of hydrofluoric acid (3.11), evaporate to near dryness, add 3 ml of hydrofluoric acid (3.11) to evaporate to dryness, and continue heating until the white smoke of sulfuric acid is completely driven out, place it in a high-temperature furnace at 950°C and burn for 10 minutes, take it out and cool it slightly, place it in a desiccator, weigh it after cooling it to room temperature, and repeat the burning until constant weight. 5 Calculation of analysis results
Calculate the percentage of silicon dioxide according to formula (1): Si0, (mm) = (mm) x 100% - Www.bzxZ.net
Formula fmr
Mass of platinum pan and precipitate before hydrofluoric acid treatment, g: ma--Mass of platinum crucible and residue after hydrofluoric acid treatment, g; Mass of platinum crucible and blank precipitate before hydrofluoric acid treatment·g: m
Mass of platinum crucible and blank residue after hydrofluoric acid treatment,; m Sample weight, g.
6 Tolerance
The difference in analysis results between laboratories should not exceed the tolerances listed in Table 1. When calibrated with standard samples, the result deviation should not exceed 1/2 of the tolerances listed in Table 1
Silicon oxide content
35. 00~~60. 00
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