GB/T 3653.4-1988 Chemical analysis methods for ferroboron - EDTA volumetric method for determination of aluminum content
Some standard content:
National Standard of the People's Republic of China
Methods for chemical analysis of ferroboron
The EDTA volumetric method for thedetermination of aluminium contentSubject content and scope of application
This standard specifies the determination of aluminium content by the EDTA volumetric method. This standard is applicable to the determination of aluminium content in ferroboron. Determination range: 1.00% to 8.00%. 2 Summary of method
UDC 669.15'781
GB3653.488
Substitute GB 3653.4-83
The sample is dissolved with nitric acid and hydrofluoric acid. After filtering out the residue, the filtrate is placed in a 7ml/. hydrochloric acid medium and iron is extracted and removed with methyl isocyanate. The residue is melted with sodium pyrosulfate, and after leaching, it is combined with the main solution. Then, aluminum, manganese, residual iron and other impurities are separated with sodium hydroxide. Excess EDTA is added. Under the condition of pH 5.5, PAN is used as an indicator. After the excess EDTA is titrated back with copper sulfate standard solution, sodium fluoride is added to release the EDTA complexed with aluminum. Then, copper sulfate standard solution is used to titrate together. According to the consumption of standard solution, the percentage of aluminum is calculated. 3 Reagents
3+1 Sodium pyrosulfate
3.2 Sodium oxychloride.
3.3 Nitric acid (pl. 42 g/ml.).
3.4 Hydrochloric acid (p1.198/mL).
3.5 Hydrochloric acid (1+1).
3.6 Hydrochloric acid (7 mol/1.).
3.7 Hydrochloric acid (5+95).
3.8 Hydrofluoric acid (pl.15 g/mL),
3.9 Perfluoric acid (pl.67 B/mL).
3.10 Methyl isobutyl ketone.
3.11 Hydrogen peroxide (pl.10 g/nL).
3.12 Sodium hydroxide solution (100 g/L), 3.13 Sodium hydroamine solution (5 g/L).
3,14 Phenolic acid indicator; weigh 0.5 g phenolic acid and dissolve it in 600 ml ethanol, add 40 mL water, mix. 3.15 PANCI-(2-pyridylazo)-2-phenol indicator, PAN ethanol saturated solution (pour the upper clear liquid after standing for later use). 3.16 Acetic acid-sodium acetate buffer solution (pH 5.5): Weigh 200g sodium acetate (CHCO00Na·3H:0) and dissolve it in 500mL water, add 9mL glacial acetic acid (p 1.05 g/mL), dilute with water to 1000mL, and mix. 3.17 Aluminum standard solution: Weigh 0.2000g metal aluminum (99.98%) and place it in a 250mL beaker, add 5mL water, and add 5mL sodium hydroxide (3.12) in batches. After heating and dissolving, neutralize with hydrochloric acid (3.5) and add 10mL excess. After boiling and dissolving, cool and transfer to a 1000mL volumetric flask. Dilute with water to the mark and mix. 1 mL of this solution contains 0.000 2 g of aluminum, 3.18 Copper sulfate standard solution (0.01 mol/L); 3.18.1 Preparation: Weigh 2.496 8ε copper sulfate (CuS0,5H,0), place it in a 300 mL beaker, dissolve it in water, transfer it to a 1 000 mL container, add 1-2 drops of sulfuric acid (1.84 g/ml), dilute to degree with water, and mix. 3.18.2 Calibration: Pipette 20.00 mL of EDTA standard solution (3.19) into a 300 mL conical flask, add 50 mL of water and 2 drops of phenolic acid indicator (3.14). Add sodium hydroxide solution (3.12) until it turns red, then neutralize with hydrochloric acid (3.5) until it is just colorless, and add 1~2 drops of excess, then add 15 mL. 2. Acid-sodium acetate buffer solution (3.16), heat to boiling, remove, add 8~10 drops of PAN indicator (3.15) towards the heat, and titrate with copper sulfate standard solution (3.18) until it turns clear purple-red. Calculate the volume ratio coefficient of copper sulfate standard solution converted to EDTA standard solution according to formula (1): Where: &—volume ratio coefficient of copper sulfate standard solution converted to EDTA standard solution; FI—volume of EDTA standard solution transferred, mLF2—volume of copper sulfate standard solution consumed in titration, mL. 3.19 Standard solution of ethylenediaminetetraacetic acid disodium dihydrate (EDTA) (0.01 mol/L). 3.19.1 Preparation: Weigh 3.7226 g EDTA and place it in a 300 mL beaker. Add water to dissolve it, transfer it to a 1000 mL volumetric flask, dilute it to the mark with water, and mix well.
3.T9.2 Calibration: Pipette 15.00 mL of lead standard solution (3.17) into a 400 mL conical beaker, add 80 mL of water, 20.00 mL of LEDTA standard solution (3.19.1), add 2 drops of phenol indicator (3.11), neutralize with sodium hydroxide solution (3.12) until it turns red, then use hydrochloric acid (3.5) to make it just colorless, and add 1 to 2 drops of excess, add 15 mL of acetic acid-sodium acetate buffer solution (3.16), boil for 2 to 3 min, remove and proceed according to analysis step 5.3.6.
When making the calibration, make a reagent blank.
Calculate the titer of the EDTA standard solution to aluminum according to formula (2): 0. 000 2 × V
The titer of the ELTA standard solution to aluminum, 2/mL; - The volume of the standard solution removed, ml
The volume of the copper sulfate standard solution consumed when adding sodium fluoride and then back-titrating, mL- - The volume of the copper sulfate standard solution consumed when adding sodium fluoride and then back-titrating, m. - The volume ratio coefficient of the copper sulfate standard solution converted to the EDTA standard solution. 3.20 Sodium fluoride solution (50g/L).
4 Sample
The sample should pass through a 0.088mm sieve.
5 Analysis steps
5.1 Sample quantity
Weigh 0.1000 g of sample (when the aluminum and lead content of the sample is less than 1%, weigh 0.2000 g). (2)
5.2 Control white test
Carry out the empty self-test together with the sample.
Co 3653.488
5.3.1. Cover the sample in platinum blood, add 2~3mL water, add 5mL nitric acid (3.3) dropwise, after the reaction stops, add 2mL hydrofluoric acid (3.8), 5mL perchloric acid (3.9), heat to dissolve. Evaporate to 1~2mL, cool, add 10mL hydrochloric acid (3.5), heat to dissolve salts, remove the thermophilic solution and filter it into a 250mL beaker with quantitative filter paper, wash the residue with hot hydrochloric acid (3.7) 5~6 times, and then wash with water 2~3 times: 5.3.2 Heat and evaporate the filtrate to dryness, cool, add 10mL hydrochloric acid (3.6) to dissolve salts, wash into a 125mL pear-shaped separatory funnel with hydrochloric acid (3.6), add 25mL methyl isobutyl ketone (3.10), shake for 2 hours. min, after standing for stratification, put the water phase into the original beaker, add 10 mL of acid (3.6) to the separatory funnel, shake for 20, after standing for stratification, put the water phase back into the original beaker, discard the organic acid, add 3 mL of nitric acid (3.3) and 5 mL of perchloric acid (3.9) to the beaker, heat and evaporate until syrupy, cool, add 0 mL of hydrochloric acid (3.7) and 5 drops of chlorine peroxide (3.11), heat to dissolve the salts, cool (main storage). 5.3.3 Put the residue and filter paper in 3 mL of platinum, carbonize, burn in a 600℃ high temperature furnace for 2 min, take out and cool, add 2 mL of sodium hyaluronate (3.1), dry, melt at 80~90℃ for 5 min, take out and cool, add 15 mL of hot water to the platinum, heat to drain the molten block, wash into the original burnt container and combine with the main liquid. 5.3.4 Add 2 8 sodium hydroxide (3.2) to the test solution, wait for it to dissolve, add 3-5 drops of hydrogen peroxide (3.11), boil for 2 nit, remove; filter with quantitative filter paper while hot into a 100L closed beaker, clean the beaker with hot sodium hydroxide solution (3,13), wash the precipitate with 78 drops, and remove the precipitate.
5.3.5 Add 10-15 ml excess EDTA standard solution (3.19), 2 drops of phenolic acid indicator (3.11) to the filtrate, mix with hydrochloric acid (3.5) until it is colorless, and add 1-2 drops excess, add 15 mL acetic acid-sodium acetate buffer solution (3.16), boil for 2-3 minutes,5.3.6 Add 7-8 drops of PAN indicator (3.15), titrate with copper sulfate standard solution (3.18) until it turns clear purple, add 15 mL of sodium fluoride solution (3.20), boil for 2-3 min, remove, add 3-4 drops of PAN indicator (3.15), titrate with copper sulfate standard solution (3.18) until it turns clear purple as the end point. 6 Calculation of analysis results
Calculate the percentage of aluminum according to formula (3):
A1(%) = T + (VA
Wherein, r-the titer of aluminum with EDTA standard solution/mL+&--·-the volume ratio coefficient of copper sulfate standard solution converted to EDTA standard solution V--the volume of copper sulfate standard solution consumed when the test solution is back-titrated after adding sodium fluoride, mL. V--the volume of copper sulfate standard solution consumed when the blank accompanying the sample is back-titrated after adding sodium fluoride, mL+batch-sample volume, 8
7 Allowable difference
The difference in analysis results between laboratories should not be too large as shown in the following table: 3
Additional instructions:
1.00~2.00bZxz.net
22. 00~4. 00
This standard was drafted by Dingyang Ferroalloy Factory
The drafters of this international standard are Wang Qian and Liu Sulan. The level of this standard is marked
GB 3653.4—88
QB3653.4881
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