This standard specifies the determination of boron content by alkali titration. This standard is applicable to the determination of boron content in ferroboron. Determination range: 3.00%~26.00%. GB/T 3653.1-1988 Chemical analysis method of ferroboron Determination of boron content by alkali titration GB/T3653.1-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methuds for chemical analysis nf ferrohoronThe alkalimetric methad for thedetermination of boron cantent1 Subject content and scope of application
This standard specifies the determination of boron content by alkalimetric titration. This standard is applicable to the determination of boron content in ferroboron. Determination range: 3.0%~26.00%. 2 Method summary
UDC 669. 15'787
GB 3653.1
Replaces 3653. 1- 83
The sample is dissolved in potassium carbonate sodium-sodium peroxide and then precipitated with water, and iron, manganese, nickel, etc. are separated by dry filtration. Take part of the filter and add citric acid to conceal the aluminum. Using an acidometer as an indicator, adjust the test solution to pH 6.9. Add mannitol and titrate with sodium hydroxide standard solution until pH 6.9 is the end point.
3 Reagents
3.1 Sodium potassium carbonate.
3.2 Sodium peroxide.
3.3 Glycerol.
3.4 ​​Citric acid solution (20 8/L).
3. 5 Salt (1+1),
3.6 Methyl red indicator (1g/L).
3.7 Sodium hydroxide solution (100g/L).
3. 8 Ethanol.
3.9 Boron standard solution: Weigh 11.1320g of standard acetic acid, place in a 500mL beaker, add 200mL of water, dissolve, transfer to a 500ml volumetric flask, dilute to scale with water, and mix. This solution contains 0.0040% boron in 1mL. 3.10 Sodium hydroxide standard solution (NaOH)—0.1mol/l. 3. 10. 1 PreparationWww.bzxZ.net
Weigh 4g of sodium hydroxide, dissolve in 250mL of water, add 10mL of barium hydroxide solution (100g/L), boil for 1-2min, cool, and dilute to 1L with water. Mix well. After the acetic acid precipitate sinks, siphon the upper clear liquid into another bottle and use it after calibration. 3.10.2 Calibration
Pipette 5.00mL of boron standard solution (3.9) into a 250mL beaker, add 100mL of water and 1mL of citric acid solution (3.4), insert an electric plate, connect the acidity meter, start the electromagnetic stirrer, and adjust the solution to pH 6.9 with sodium hydroxide solution (3.7). Add 20g of H-Nitrol (3.3). Titrate with sodium hydroxide standard solution (3.10) to pH 6.9, which is the end point. The titration degree T (/mL) of sodium hydroxide standard solution to boron is calculated according to formula (1): Approved by the Ministry of Metallurgical Industry of the People's Republic of China on December 20, 1988 and implemented on January 1, 1990
GB3653.1---88
In the formula, s—the volume of boron standard solution pipetted during titration, mL; .-1mL boron standard solution content, g/ml. VI—the volume of sodium hydroxide standard solution used during titration, ml. 4 Instruments
Acidity meter, glass electrode, argon dioxide, electromagnetic stirrer. 5 Sample
The sample should pass through a 0.088 rm sieve.
6 Analysis steps
6.1 Sample quantity
Weigh the sample.
6.2 Blank test
Carry out a blank test with the sample.
6.3 Determination
6.3.1 Place the sample (6.1) in a nickel (iron) crucible containing 1g of potassium sodium carbonate (3.1), stir with a plastic rod, place in a high-temperature furnace at 500-600°C, heat until the sample and flux just turn red, take out and cool. Add 6g of sodium peroxide (3.2) to the top of the furnace, wait until the peroxide turns into a boron, then place in the middle of the high-temperature furnace (furnace temperature 800-850°C), take out and cool. 6.3.2 Place the crucible containing the melt in a 300ml quartz beaker containing 120mL of water, heat it, add 2mL of ethanol (3.8), boil for 3-5min, take out and wash (if a little melt is found to stick to the bottom, use a few drops of hydrochloric acid (3.5), heat it slightly to dissolve it, and then merge it into the main solution). Cool, transfer to a 500mL volumetric flask, dilute to scale with water, stir, and let stand for a while. 6.3.3 Filter with double-layer fast filter paper 1, transfer 100.0mL of filtrate, place in a 300mL quartz beaker or a boron-free glass beaker, add 10mL citric acid solution (3.4). Add 2 drops of methyl red indicator (3.6), neutralize with hydrochloric acid (3.5) until it turns red, cover with surface III, heat and boil for 10 minutes, cool to room temperature, add water to make the test solution volume about 120mL, connect the electrode and acidity meter, and start the stirrer. Adjust to pH 6.9 with sodium hydroxide solution (3.7), add 20g mannitol (3.3), and under continuous stirring, use sodium hydroxide standard solution (3.10) to determine the pH to 6.9, which is the end point.
7 Calculation of results
The percentage content of boron R (%) is calculated according to formula (2): (VV) XT
Wherein: V2--
8 Allowable difference
The volume of sodium hydroxide standard solution consumed by titrating the test solution, mL; The volume of sodium hydroxide standard solution consumed by titrating the blank with the sample, mL; The titer of sodium hydroxide standard solution on boron g/mLt sample volume +
-test fraction ratio.
The difference in the analysis results between the experimental cases should not be greater than the allowable difference listed in the following table, (2)
>10. 00--15. 00
-15. 00~~20. 00
Additional instructions:
This standard was drafted by Benxi Iron and Steel Company. The drafter of this standard is responsible for the original meaning.
GB 3653. 1
This standard is equivalent to the United Nations standard TOCT 14021.178 "Determination of iron by chemical analysis method". The level of this standard is marked GB3563.1-88
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