GB/T 4700.3-1984 Chemical analysis methods for silicon-calcium alloys - EDTA titration method for determination of aluminum content

GB/T 4700.3-1984 Chemical analysis method for silicon-calcium alloys - Determination of aluminum content by EDTA titration GB/T4700.3-1984 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical analysis of calcium -siliconThe EDTA titrimetric method for thedetermination of aluminitm contentThis standard is applicable to the determination of alumina content in calcium -silicon alloys. Determination range: 0.50~3.00%. This standard complies with GB1467"78 "General principles and provisions of the standard for chemical analysis methods of metallurgical products". Summary of methods
DC 669.782
5891:543
244.6-546.621
GB 4700.3-84
The sample is dissolved in nitric acid and chlorofluoric acid. In a strong acidic medium of pl5, add 1% FDTA to complex the solution, and use diphenol orange as an indicator: use a standard solution to determine the excess FDTA, add sodium hydroxide to complex the solution and release an equivalent amount of FDT, which can be titrated with a zinc standard solution. According to the consumption, calculate the percentage of aluminum. 2 Reagents
2.1 Pyrosulfate.
2.2 Hydrofluoric acid (specific gravity 1.15)
2.3 Nitric acid (specific gravity 1.40).
Hydrochloric acid (batch weight 1.19),
Hydrochloric acid (+)
Hydrochloric acid (+100).
Sulfuric acid (1 -5).
Ammonium hydroxide (11).
Sodium hydride solution (30%), store in plastic bottle. Sodium fluoride solution (3%), store in plastic bottle. Hexamethylenetetramine solution (25%).
Hexamethylenetetramine solution (1.5%). Additive (0.1%): weigh 0.1g portion, add 60ml of alcohol solution: grind with water to 100ml, mix, 2.13
Acid sulphuric acid: [Dihydrogen phenol is added to sodium chloride and ground, mix buffer solution: dilute Take 500g of ammonium acetate, add water to dissolve, and dilute to 1000ml (adjust to pH 52.5 with hydrogen or acid). 2.16 EDTA solution (0.015M): weigh 5.5836g of ethylenediaminetetraacetic acid (CmHN2,Na,-2H,O) which has been pre-dried at 80℃, pour into water, transfer to a 1000ml container, dilute with water to 300 degrees, and arrange. 3 samples. The sample should pass through a 0.1251mm sieve: National standard 198±-10 -04 IssuedbzxZ.net
198509-01 Implementation
4 Analysis steps
4.1 Sample α
Weigh 0.5000g of sample.
4.2 Blank test
Carry out a blank test with the previous sample.
4.3 Determination
GB 4700.3-84
4.3.1 Heat the sample (4.1) to 14 °C, add 30 ml of water, 10 ml of nitric acid (2.3), and add chlorofluoric acid (2.2) dropwise until the sample is completely decomposed. Add 1 ml of water. Heat the mixture to make it about 10 ml. 4.3.2 Remove the sample and rinse it with sulfuric acid (2.7) until it is completely cooled. Heat the solution until it is more concentrated than the existing sulfuric acid. Remove the sample from the cooling tube, rinse the tube with water, and then evaporate the sulfuric acid fumes under low heat. Repeat the washing and evaporation twice. 4.3.3 Remove the sample from the cooling tube, add 20 ml of hydrochloric acid (2.5) and 40 ml of hot water. Heat to dissolve the soluble salts and burn. Rinse the tube with hot acid (2.) 5 to 6 times and burn 1600 ml of the filtrate (rejected liquid). 4.3.4 Filter the residue into a precipitate, incinerate at low temperature, burn at 70-80℃, then add potassium sulfate and calcine at 700-100℃ for 10-15min
4.3.5 Take out the crucible and cool it, put it into 50ml hot water to melt and dissolve it, filter it, wash the residue and paper with hot water for 1-6 times, and add the filtrate (1.3.3). 4.3.6 Take about 100ml of the above solution and grind it to 3 with ammonia (2.8), add 25-30ml of 3-4 stream hydrochloric acid (2.5)! Heat the liquid (2.11) until it is clear, remove the beaker, let it stand at 80-90℃ for 15-20mia, remove the beaker, mix, wash the precipitate with the liquid (2.12) 8-10 times, blow the precipitate water into the original beaker, flush the filter paper with 20ml hot water (2.5) and decompose the precipitate, wash the filter paper with water, and heat to decompose the oxide completely. 4.3.7 Add 10-15ml of the original hot water (4.3.6) to 100ml hot water, heat to boiling, remove the beaker, slowly pour the liquid into the beaker containing 10ml sodium hydroxide solution (2.9), heat to boiling for 2-3min, remove and cool. Transfer the liquid to a 250ml container, fill it up to the mark with water, and mix. After standing, filter. 4.3.8 Take 200.00 ml of the filtrate (4.3.7), place in a 500 mL sodium hydroxide solution, add 10 ml hydrochloric acid (2.4), 40 ml EDTA solution (2.1), and add 2-3 drops of phenolic acid indicator (2.13). Rinse with hydrochloric acid (2.4) until the pink color disappears. Add 15 ml buffer solution (2.15) and titrate for 3-4 minutes. Remove the cone, cool to room temperature, add 0.1 g of diphenol orange indicator (2.11), and zinc standard solution (2.17) until the color changes from yellow to red. 4.3.9 Add 30 ml of sodium hydroxide solution (2.0), titrate for 3 minutes, remove the cone, add 0.1 g of diphenol orange indicator (2.14), and titrate with zinc standard solution (2.17) until the solution changes from yellow to orange-red. The colors of the endpoints of the two titrations should be consistent. Record the volume of the zinc standard solution that was added the second time! 5 Calculation of the analysis results
According to the formula:
Al(）
(F:V) × 0.0004047
Wherein: the volume of the zinc standard solution that was removed by titration, m is the volume of the standard solution removed when the test number is empty. ml, me--test ht, g:
-test change [the titer of the group
0.00047-zinc standard solution (0.1500M), ml, analysis results are expressed as decimals
Allowable difference
GB4700.3-84
The correlation between the analysis results should not be greater than the allowable correlation values ​​listed in the following table.
0.50~1.0m
31.00 -3.00
Additional remarks:
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China.
This standard was drafted by the Alloy Steel Plant of the Capital Iron and Steel Company. From the date of implementation of this standard, the original Ministry of Metallurgical Industry Standard YB579-65 "Chemical Analysis Method of Silicon Calcium Alloy" will be used as a separate document. %
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