JB/T 9220.3-1999 JB/T 9220.3-1999 Chemical analysis of acidic slag from foundry cupola - Determination of ferrous oxide content by potassium dichromate volumetric method JB/T9220.3-1999 Standard download decompression password: www.bzxz.net

JB/T 9220.3
This standard is a revision of JB/7.284.3--87 "Chemical analysis method of acidic slag of foundry cupola furnace - determination of ferrous oxide content by potassium dichromate volumetric method". During the revision, the original standard was edited, and the main technical content remained unchanged. This standard replaces JB/7.284.3-87 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Foundry Standardization. The drafting units of this standard are: Shanghai Diesel Engine Factory, Nanchang Diesel Engine Factory, Guiyang Foundry, Shenyang Foundry, Shanghai Tractor Engine Co., Ltd., Huagang Steel, Wuxi Diesel Engine Factory, Changzhou Diesel Engine Factory, etc. The main drafters of this standard are: Shi Zhihan, etc. 429
1 Scope
Standard of the Machinery Industry of the People's Republic of China
Chemical analysis methods for acid slay of cupola-Determination of ferrous oxide by volumetricmethod using potassium dichromateJB/T9220.3.1999
Replaces JB/7.284.3.- 87
This standard specifies the determination of ferrous oxide in chemical analysis methods. Determination range: 1.00% to 20.00%. This standard is applicable to the analysis of the composition of acid slag of cupola. 2 Test conditions
The sample is decomposed by heating at low temperature with hydrochloric acid-hydrofluoric acid in a carbon dioxide atmosphere. The titration is carried out in a sulfuric acid-phosphorus medium. In order to eliminate the interference of fluoride ions, add saturated boric acid solution to generate a stable complex of fluoroboric acid, use sodium diphenylamine sulfonate as an indicator, and titrate with potassium dichromate standard solution.
The sulfur content of less than 0.8 mg in the titration solution does not interfere with the determination. 3 Reagent preparation
3.1 Sodium bicarbonate.
3.2 Hydrochloric acid-hydrofluoric acid mixed acid: Add 100 ml of water, 100 ml of hydrochloric acid (density 1.19 g/ml), and 20 ml of hydrofluoric acid (density 1.15 g/ml) in a plastic cup and mix well.
3.3 Sulfuric acid-phosphoric acid mixed acid: sulfuric acid (density 1.84g/mL) + phosphoric acid (density 1.70g/ml.) + water (150+150+700), mix well,
3.4 ​​Saturated boric acid solution
3.5 Sodium diphenylamine sulfonate solution (0.12%): weigh 0.12g sodium diphenylamine sulfonate and dissolve it in 100mL water towel, add 2 drops of sulfuric acid (density 1.84g/ml), mix well.
3.6 Potassium dichromate standard solution (0.02000N): weigh 0.9806g standard potassium dichromate (pre-dried at 150C for 1h, placed in a desiccator and cooled to room temperature) and dissolve it in water and transfer it to a 1000mL volumetric flask, dilute it with water to the scale, and mix well. 4 Instruments
Reduction device See Figures 1 and 2.
Approved by the State Bureau of Machinery Industry on June 24, 1999 430
Implemented on January 1, 2000
5 Analysis steps
5.1 Sample quantity
Reduction device
Weigh the sample quantity according to Table 1.
Ferrous oxide content, %
1.00～5.00
≥5. 00～20.00
5.2 Determination
JB/T 9220.3—1999
Glass
Figure 2 Reduction tube
Sample quantity…
5.2.1 Place the sample (5.1) in a 500mL conical flask filled with a small amount of water and shake the sample to avoid caking. 5.2.2 Add 1-2g sodium bicarbonate (3.1), 25ml water, and then add 50ml hydrochloric acid-hydrofluoric acid mixture (3.2), and place the reduction tube with saturated sodium bicarbonate solution on a hot plate to heat and decompose the sample at low temperature until a white precipitate is produced in the solution. Note: If there is no reduction tube, a porcelain cover can be used.
5.2.3 Remove, quickly cool with running water, unplug the reduction tube, immediately add 100ml water, 25ml sulfuric acid-phosphoric acid mixture (3.3), 25ml boric acid saturated solution (3.4), add 5-7 drops of sodium diphenylamine sulfonate solution (3.5), and immediately titrate with potassium dichromate standard solution (3.6) until purple-red is the end point.
Note: Unplug the reduction tube until the end of titration, which is required to be controlled within 2min. 5 Calculation of analysis results
Calculate the percentage of ferrous oxide according to formula (1): FeOWww.bzxZ.net
Wherein: V-
×100%
m X 1000
-The volume of potassium dichromate standard solution consumed in titration, ml. The equivalent concentration of potassium dichromate standard solution; - Sample volume·g:
7Tolerance
The amount of ferrous oxide.
The difference in the analysis results between the experimental spaces should not be greater than the tolerances listed in Table 2. When calibrating with standard samples, the deviation should not exceed 1/2 of the 431
tolerances listed in Table 2.
Ferrous oxide content
1.00~3.00
>3. 00~5. 00
>5. 00 ~~ 7. 00
JB/T9220.3-1999
Ferrous oxide content
7. 00~10. 00
>10.00~20.00)
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