GB/T 4701.6-1984 Chemical analysis methods for ferrotitanium - Determination of aluminum content by 8-hydroxyquinoline volumetric method
Some standard content:
National Standard of the People's Republic of China
Methods for chemical analysis of ferrotitaniumThe B-hydoxyquinoline volumetric method forthe determination of aluminium contentThis standard applies to the determination of aluminium content in ferrotitanium. The determination range is 3.00-12.00%. UDC 669.16'295
: 543.24: 546
GB 4701.6—84
This standard complies with GB1467-78 "General Principles and General Provisions for Standards of Chemical Analysis Methods for Metallurgical Products". 1 Summary of the method
The sample is dissolved in hydrochloric acid, oxidized with nitric acid, and iron and titanium are separated by alkali. Take part of the filter cloth, acidify with hydrochloric acid, adjust to slightly alkaline, add 8-hydroxyquinoline to precipitate aluminium, and filter. Dissolve the precipitate with hydrochloric acid, add an excess of potassium bromate standard solution, then add potassium iodide to generate iodine, use starch as an indicator, titrate with sodium thiosulfate standard solution, and calculate the aluminum content. 2 Reagents
2.1 Sodium peroxide.
2.2 Nitric acid (specific gravity 1,42).
2.3 Ammonium hydroxide (1+1).
2.4 Hydrochloric acid (1 + 1).
2.5 Hydrochloric acid (1+2).
2.B Hydrochloric acid (1+3).
2.7 Tar acid solution (50%).
2.B Potassium iodide solution (10%).
2.9 Starch solution (0,5%).
2.10 Alkaline solution, dissolve 300g sodium hydroxide in 200ml 20% ammonium phosphate solution and 800ml water, mix with a spoon. 2.11 8-Hydroxyquinoline solution (2%): Weigh 2g 8-hydroxyquinoline, dissolve in 10ml acetic acid, dilute to 100ml with water, mix well, and store in a brown bottle. Each time this solution is used, take a certain amount, add ammonium hydroxide (2.3) dropwise to neutralize until a small amount of white precipitate is produced and no longer dissolves, heat to dissolve the precipitate, filter immediately, and use the filtrate. When the aluminum content in the test solution is 0.01g, 15ml 8-hydroxyquinoline solution should be added.
2.12 Indigo disulfonate sodium solution (0.25%): Dissolve 0.25g indigo disulfonate sodium in 100ml hot water, and filter if there is insoluble matter after cooling before use.
2.13 Sodium thiosulfate standard solution (about 0.1N) 2.18.1 Preparation
Weigh 26g sodium thiosulfate (NaS,O,·5H,O) and 0.2g anhydrous sodium carbonate, place in a 500ml beaker, add appropriate amount of water without carbon dioxide to dissolve them, transfer to a 1000ml container bottle, add 10ml isopentanol, dilute to the scale with water without carbon dioxide, mix well, and calibrate after leaving for two days.
2. 13,2 Calibration
Weigh 1.0000g potassium iodate (standard reagent) dried at 120~140℃, place in a 300ml beaker, add appropriate amount of water to dissolve, transfer to a 250ml volumetric flask, dilute to scale with water, and mix. Transfer 25.00ml of the solution to a 500ml conical flask with a grinding stopper, add 2g potassium iodide and 5nl sulfuric acid (1+5), immediately cover the stopper and shake gently, place in a dark place for about 5min, titrate with sodium thiosulfate standard solution (2.13.1) until light yellow, add 5ml of swirl solution (2.9), and continue titrating until the blue disappears, which is the end point.
Do a blank test during the test.
Calculate the equivalent concentration of sodium thiosulfate standard solution according to the following formula. C
m×100
35.67 (V-Vol)
Where: C…The concentration of sodium thiosulfate standard solution, mbZxz.net
Weigh the mass of potassium iodate (reference reagent), g. The volume of sodium thiosulfate standard solution consumed during calibration, ml; The volume of sodium thiosulfate standard solution consumed during blank test, nl: The gram equivalent of potassium iodate.
2.14 Potassium bromate standard solution (about 0.1N). 2.14.1 Preparation
Weigh 2.8g potassium bromate, 12g potassium bromide and 1g potassium hydroxide, place in a 500ml beaker, add appropriate amount of water to dissolve, transfer to a 1000ml volumetric flask, dilute to the scale with water, and mix well. 2.14.2 Calibration
Pipette 25.00ml potassium bromate standard solution (2.14.1) and place it in a 500ml conical flask with a ground stopper. Add 1g potassium iodide and 5ml hydrochloric acid (2+1). Immediately cover the stopper and shake gently. Place in a dark place for 2~3min. Add sodium thiosulfate standard solution (2.13) until it turns light yellow. Add 5ml starch solution (2.9) and continue to titrate until the blue color disappears. This is the end point. Perform a blank test from time to time.
Calculate the concentration of potassium bromate standard solution according to the following formula. C =
Concentration of potassium bromate standard solution, N,
Where: C.
C.(V.-Vo.)
Concentration of sodium thiosulfate standard solution after calibration, N, Va
3Sample
Volume of sodium thiosulfate standard solution consumed during calibration, ml: Volume of sodium thiosulfate standard solution consumed in blank test, ml Volume of potassium bromate standard solution pipetted, ml. The sample should pass through a 0.125mm sieve.
Rate analysis steps
4.1 Sample size
Weigh 0.5000g of sample.
4.2 Blank test
Perform a blank test with the sample.
4.3 Determination
4.3.1 Place the sample (4.1) in a 200ml beaker, add 30ml hydrochloric acid (2.6), cover with a watch glass, place on an electric stove and heat until the sample is completely dissolved. Add 2ml nitric acid (2.2) to oxidize iron and other substances, continue heating to concentrate the volume to 10-15ml, add it dropwise to a 500ml beaker containing 150ml hot alkaline solution (2.10), wash the original beaker, precipitate iron and titanium, dilute with hot water to about 300ml, heat to boiling, add 0.5-2g sodium peroxide (2.1), continue boiling for about 5min, precipitate manganese. GB 4701.6-84
4.3.2 Cool to room temperature, transfer to a 500ml volumetric flask, dilute to scale with water, and mix. Filter with a quantitative filter paper. 4.3.3 Take 50.00~100.00ml of the filtrate and place it in a 250ml beaker, add hydrochloric acid (2.4) to make it acidic (pl1~2), add 10ml of tartaric acid solution (2.7), and neutralize it with ammonium hydroxide (2.3) to pH7~8. 4.8.4 Heat the solution (4.3.3) to 80℃, add 8-quinoline solution (2,11) while stirring to make aluminum form 8-hydroxyquinoline aluminum precipitation, then adjust the pH to 7~8 with ammonium hydroxide (2.3), keep it warm and let it stand for 20 minutes. 3.5 Filter it with medium-speed fixed mouse filter paper, wash it with warm water 2~3 times, and then rinse it with water. ..6 Dissolve the precipitate (4.3.5) several times with 40ml hot hydrochloric acid (2.5), wash the filter paper several times with warm water, cool the solution to room temperature, add 23 drops of sodium indigo disulfonate solution (2.12), accurately add potassium bromate standard solution (2.14) until the blue color of the solution disappears and the color of bromine appears on the tablet, and add 10ml potassium iodide solution (2.8) in excess of 1-2ml, titrate with sodium thiosulfate standard solution (2.13) until it turns light yellow, add 5ml starch solution (2.9), and continue titrating until the blue color disappears, which is the end point. 5 Calculation of analysis results
Calculate the percentage of aluminum according to the following formula:
[(V, - Vs +K) - (Vos -Vo4 -K)] -C( ×0.002248Al (%)
Wu Zhong: C
Concentration of potassium bromate standard solution after calibration, N, - volume of potassium bromate standard solution added during determination, ml; ×100 ....(3)
-The volume of sodium thiosulfate standard solution consumed in titrating excess potassium bromate standard solution during the determination, ml; The volume of potassium bromate standard solution added in the blank test, mEThe volume of sodium thiosulfate standard solution consumed in titrating excess potassium bromate standard solution during the blank test, ml: The ratio of sodium thiosulfate standard solution to potassium bromate standard solution; Sample volume, g1
Test solution split ratio
Milligram equivalent of aluminum.
The analysis results are expressed to two decimal places. 6 Tolerance
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table. Aluminum
3.00 ~6.00
26.00~12.00
Additional remarks:
This standard is proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by Jinzhou Ferroalloy Factory of the Ministry of Metallurgical Industry. From the date of implementation of this standard, the former Ministry of Metallurgical Industry standard YB581-65 "Chemical Analysis Method of Ferrotitanium" will be invalid.
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