GB/T 15076.1-1994 Chemical analysis method of tantalum and niobium - Determination of tantalum content in niobium
Some standard content:
National Standard of the People's Republic of China
Chemical analysis methods for molybdenum saws
Determination of molybdenum content in saws
Methods for chemical analysis of tantalum and niobium-Deterimihation of tantalum content in niobiumGB/T 15076.194
Part I Method 1 Chromatographic separation 5-Br-PADAP spectrophotometry 1 Subject content and scope of application
This standard specifies the method for the determination of molybdenum content in tantalum. This standard is applicable to the determination of molybdenum content in saws, and also to the determination of molybdenum content in its hydroxide and carbide. Determination range: 0.015%~0.2%.
2 Reference standards
GB1.4 Guidelines for standardization work Provisions for the preparation of chemical analysis methods GB1467 General principles and general provisions for chemical analysis methods for metallurgical products GB7729 General principles for spectrophotometric methods for chemical analysis of metallurgical products 3 Principles of the method
The sample is dissolved in hydrofluoric acid and nitric acid, and separated from molybdenum and other impurities by paper chromatography. It is melted with potassium pyrosulfate and leached with tartaric acid. In the sulfuric acid medium, molybdenum forms a colored complex with 2-[(5-bromo-2-pyridine)-azo}-5-diethylaminophenol, and its absorbance is measured at a wavelength of 562nm on a spectrophotometer.
4 Reagents and materials
4.1 Potassium pyrosulfate.
4.2 Hydrofluoric acid (pl.14g/mL).
4.3 Nitric acid (p1.42g/mL).
4.4 Butanone.
4.5 Hydrofluoric acid (1+1).
4.6 Developing agent: butanone + hydrofluoric acid + nitric acid (90+5+5). 4.7 Tartaric acid solution (150g/1).
4.8 Tartaric acid solution (60g/L).
4.9 Potassium pyrosulfate solution (100g/L): Weigh 10g of potassium pyrosulfate (4.1) and place it in a 30ml porcelain crucible, melt it on a blowtorch until transparent, and cool it. Place it in a 150mL beaker filled with 80mL water, heat it to dissolve the frit, wash out the crucible with water, and cool it. Transfer it to a 100mL volumetric flask, dilute it to the mark with water, and mix it well.
4.10 Color developer solution: weigh 0.03g 2-[(5-bromo-2-pyridine)azo]-5-diethylaminophenol (5-Br-PADAP) in a 200mL beaker, add 20mL anhydrous ethanol to dissolve, transfer to a 200mL brown volumetric flask, dilute to scale with sulfuric acid (1+9), and mix well. 4.11 Molybdenum standard stock solution: weigh 0.1000g metal molybdenum powder and place in 50mL porcelain, burn in a high-temperature furnace at 600℃ for 30min, take out, and cool. Add 6g potassium pyrosulfate, first heat on a high-temperature electric furnace until white sulfur trioxide smoke appears, melt on a blowtorch until transparent, take out, and cool. Transfer the pile into a 600mL beaker containing 400mL tartaric acid solution (300g/L), heat to dissolve the sinter, remove it, wash out the snails with tartaric acid solution (300g/L), and cool it. Transfer the solution into a 1000mL volumetric flask, dilute to the mark with tartaric acid solution (300g/L), and mix. This solution contains 100μg in 1mL.
4.12 Molybdenum standard solution: Transfer 20.00mL of molybdenum standard storage solution (4.11) into a 100mL volumetric flask, dilute to the mark with water, and mix. This solution contains 20μg of molybdenum in 1mL.
4.13 Chromatographic paper: Medium-speed chromatography filter paper, 220mm×280mm, 2/3 of its length is soaked in ammonium nitrate solution (100g/L), dried and set aside. 5 Instruments and devices
5.1 Spectrophotometer.
5.2 Humidity control box: a circular, sealable container with a lid made of polyethylene welded together, 35 cm high and 40 cm in diameter. 5.3 Chromatographic layer: two 1000 mL wide-mouth polyethylene bottles, cut off the small diameter part of the bottle mouth, as the bottom and lid respectively. 5.4 Neutralizer: a large dryer with concentrated ammonia water (p0.90 g/mL) placed under the sieve plate. 5.5 Sprayer: filled with acid solution (30 g/L). 6 Analysis steps
6.1 Determination quantity
Weigh two samples, measure them independently, and take the average value. 6.2 Samples
Weigh the sample according to Table 1, accurate to 0.0001 g. Table 1
Molybdenum content
0. 015~~ 0. 070
>0. 070~0. 200
6.3 Blank test
Test sample (6.2)
Carry out a blank test together with the test sample.
6.4 Determination
Total volume of test solution
Volume of test solution
Amount of potassium pyrosulfate
Amount of tartaric acid
6.4.1 Place the test sample (6.2) in a 30mL platinum crucible, add a few drops of water to moisten it, add 1~2mL of hydrofluoric acid (4.2), add nitric acid (4.3) dropwise, wait until the violent reaction stops, heat on a low-temperature electric furnace until it is completely dissolved, continue to evaporate the solution to 0.5~1mL, remove it, and cool it. 6.4.2 Use a plastic pipette to apply the test solution in a strip shape to the part of the color paper (4.13) that is not soaked in ammonium nitrate, so that the edge of the coated strip is 3 cm away from the bottom edge of the color paper and the width of the coated strip is 2.5 to 3 cm. Dry at low temperature. Wash the crucible twice with hydrofluoric acid (4.5), 0.5 ml each time; wash the floor with butanone (4.4) 3 times, 0.5 mL each time, apply the washing solution to the coated strip in turn, dry the coated strip while applying, and roll the color paper into a cylinder. 6.4.3 Place the paper sheet (6.4.2) vertically with the coated strip at the bottom in the humidity control box (5.2), and place a 500 mL beaker containing 400 mL boiling water in the box. Wet the paper tube for 20 to 25 minutes. (This item can be omitted in areas with humid climates). 6.4.4 Take out the paper tube and immediately put it into the chromatographic layer tube (5.3) containing the developer (4.6) with a liquid layer height of 1 cm. After sealing, develop it at room temperature above 15℃ for about 3 hours. When the front edge of the developer rises to about 2 cm from the lower end, take it out and dry it. Put it on the screen plate of the neutralizer (5.4) and neutralize it until no white smoke comes out on the paper.
6.4.5 Use a sprayer (5.5) to spray the acid solution to make the saw belt color, and dry it. Cut the molybdenum belt from the bottom of the developer front to 3 cm wide, put it in a 479
GB/T 15076.1—94
30ml, porcelain crucible, carbonize it on an electric furnace, burn it at 600℃ in a high-temperature furnace until it turns white, carefully take it out, and cool it. 6.4.6 Add potassium pyrosulfate (4.1) according to Table 1, heat to remove moisture, melt it on a blowtorch until it is transparent, and cool it. Add tartaric acid solution (4.4) according to Table 1, heat at low temperature until the frit is completely dissolved, blow the wall with water, remove and cool. 6.4.6.1 Transfer the test solution (6.4.6) required for color development in full into a 25mL colorimetric tube according to Table 1, dilute to 10mL with water, and mix. 6.4.6.2 Transfer the test solution (6.4.6) required for color development in liquid separation into a 25mL volumetric flask according to Table 1, dilute to scale with water, and mix. Take 5.00mL and place it in a 25mL colorimetric tube, dilute to 10mL with water, and mix. 6.4.7 Add 5mL of color developer solution (4.10) to the colorimetric tube, dilute to scale with water, mix, and leave for 50min. 6.4.8 Transfer part of the test solution into a 1cm absorbent tube, use the reagent blank as reference, and measure its absorbance at a wavelength of 562nm on a spectrophotometer.
6.4.9 Subtract the absorbance of the blank solution accompanying the sample and find the corresponding amount of molybdenum from the working curve. 6.5 Drawing of working curve
6.5.1 Take 0, 0.50, 1.00, 2.00, 3.00, 4.00 ml of molybdenum standard solution (4.12) and place them in 25 ml colorimetric tubes respectively, make up to 5 ml with tartaric acid solution (4.8), add 4 ml of potassium pyrosulfate solution (4.9), dilute to 10 ml with water and mix well. The following operations are carried out according to 6.4.7 and 6.4.8.
6.5.2 Draw the working curve with molybdenum content as the horizontal axis and absorbance as the vertical axis. 7
Calculation and expression of analysis results
Calculate the percentage of molybdenum according to the following formula:
Where: mi
Ta(%)-mi : V. X10 e
Amount obtained from the working curve, ug;
Total volume of test solution, mL;
Volume of test solution taken, mL;
8Allowance difference
Mass of the sample, 8.
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
Molybdenum content
0. 015~~0.040
>0. 040~~0. 080
>0.080~0.130
0. 130~0. 200
Allowable difference
Part II Method 2 Chromatographic separation Pyrogallic acid spectrophotometry 9 Subject content and scope of application
This standard specifies the method for determining the content of nb in saws. This standard is applicable to the determination of molybdenum content in saws, with a determination range of 0.2%~3%. 10 Reference standards
GB1.4 Guidelines for standardization work Provisions for the preparation of chemical analysis method standards 480
GB/T 1 5076. 1-94
GB1467 General principles and general provisions for chemical analysis method standards for metallurgical products GB7729 General principles for spectrophotometric methods for chemical analysis of gold products 11 Principle of the method
The sample is dissolved in hydrofluoric acid and nitric acid. Molybdenum and other impurities are separated by paper chromatography. It is melted with potassium pyrosulfate and leached with ammonium oxalate, and molybdenum and pyrogallic acid form a yellow complex in a phosphoric acid medium. Its absorbance is measured at a wavelength of 400nm on a spectrophotometer. 12 Reagents and materials
Potassium pyrosulfate.
Ammonium oxalate.
Nitric acid (p1.42g/mL).
Sulfuric acid (pl.84g/mL)).
Phosphoric acid (pl.70g/mL).
Butanone.
Hydrofluoric acid (1+1).
12.8Developing agent: 4-methyl-pentanone-{2］+butanone+hydrofluoric acid+nitric acid (44+44+8+4). 12.9Acid solution (50g/L).
12.10Pyrogallic acid solution (200g/L): Prepare immediately before use. 12.11Molybdenum standard storage solution: Weigh 0.2000g of tantalum powder, place it in a 30mL porcelain crucible, burn it in a 600C high-temperature furnace for 30min, take it out, and cool it. Add 8g of potassium pyrosulfate (12.1), heat it on a high-temperature electric furnace until white sulfur trioxide smoke is emitted, transfer it to a 850℃ high-temperature furnace to melt until it is transparent, take it out, and cool it. Weigh 4g of ammonium oxalate into a 300mL beaker, add about 50mL of water, heat to boiling on an electric stove, transfer the oxalate into the beaker, continue heating and stirring to dissolve the sintered mass, and remove it. Wash out the sinter with water, add 2mL of phosphoric acid (12.5), continue heating and stirring on an electric stove to make the solution clear, and remove it. Cool slightly, transfer the solution into a 100mL volumetric flask, dilute with water to nearly the mark, mix, cool, dilute with water to the mark, and mix. This solution contains 2mg of tantalum in 1mL. 12.12 Molybdenum standard solution: Transfer 25.00mL of molybdenum standard storage solution (12.11) into a 100mL volumetric flask, add 1.5ml of phosphoric acid (12.5), dilute to the mark with ammonium oxalate solution (40g/L), and mix. This solution contains 500μg of tantalum in 1mL. 12.13 Molybdenum standard solution: Pipette 20.00mL of molybdenum standard solution (12.12) into a 50mL volumetric flask, add 1.0mL of phosphoric acid (12.5), dilute to the mark with ammonium oxalate solution (40g/L), and mix well. This solution contains 200μg in 1mL. 12.14 Chromatographic paper: Medium-speed chromatography filter paper 220mm×280mm, soak the chromatographic paper 2/3 along the length (280mm) with ammonium nitrate solution (100g/L), dry and set aside.
13 Instruments and equipment
13.1 Spectrophotometer.
13.2 Chromatographic box: A sealed container with a lid made of polyethylene or polyvinyl fluoride. 13.3 Neutralizer: A medium-sized desiccator can be used instead, and the lower part of the sieve plate is filled with ammonia water (p0.90g/ml). 13.4 Sprayer: Acid solution (12.9) is contained inside. 14 Analysis steps
14.1 Determination quantity
Weigh two samples, measure independently and take the average value. 14.2 Samples
Weigh the samples according to Table 1. Accurate to 0.0001g. 481
Silver content
0.20~0.50
>0. 50~1. 00
>1. 00~2. 00
>2. 00 ~3. 00
14.3 Blank test
Carry out a blank test along with the sample.
14.4 Determination
GB/T 1 5076.1—94bzxZ.net
Potassium pyrosulfate
Ammonium oxalate
Pyrogallic
Seed powder solution
Total
Absorption
Left-hand curve
14.4.1 Place the sample (14.2) in a 30mL platinum crucible, add 2mL hydrofluoric acid (12.7), drop about 0.3mL nitric acid (12.3), slowly heat until the sample is completely dissolved, continue heating to evaporate the test solution to 0.5~0.8mL. 14.4.2 Use a plastic pipette to absorb the test solution (14.4.1) and apply it to the part of the color paper (12.14) that has not been soaked with ammonium nitrate solution. The coating should be 3cm away from the bottom of the paper and the coating width should be 2~3cm. Dry at low temperature. Wash the paper twice with hydrofluoric acid (12.7), about 0.4 mL each time, and wash the paper three times with butanone (12.6), about 0.5 mL each time. Apply the washing solution to the original coated strip in turn, and dry the coated strip while applying. Roll the chromatographic paper into a round roll. 14.4.3 If the part of the chromatographic paper soaked with ammonium nitrate solution is too dry, place the paper roll (14.4.2) in a steam bath or relatively humid air to rehydrate it. Put the paper roll vertically into the chromatographic box (13.2) containing about 1 cm of developer (12.8) with the coated strip at the bottom, seal it and develop it at room temperature above 15℃ for about 3 hours. 14.4.4 When the front edge of the developer rises to 2 cm from the top of the paper, take it out and dry it. Put it on the screen plate of the neutralizer (13.3) and neutralize it until there is no white smoke on the paper. Spray the acid solution (12.9) with a sprayer (13.4) to make the buttons and saws develop color, and dry it. Cut the molybdenum strip 1 cm above the orange-yellow roller strip, place it in 30 mL porcelain, carbonize it on an electric furnace, and ash it in a 600°C high-temperature furnace. Take it out and cool it. 14.4.5 Add potassium pyrosulfate (12.1) to the porcelain (14.4.4) according to Table 1, drive off the water at the high-temperature furnace mouth, melt it at 750°C until it is transparent, take it out and cool it. Add 5 drops of sulfuric acid (12.4) to the porcelain. 14.4.6 Weigh ammonium oxalate (12.2) according to Table 1 and place it in a 100 mL beaker, add 10~20 ml of water, and heat it to boiling. Transfer the porcelain (14.4.5) into the beaker, add phosphoric acid (12.5) according to Table 1, heat it on the electric furnace and shake it until the frit is dissolved, take it out, wash it out with water, and continue to heat and stir it to make the solution clear. After cooling slightly, transfer the test solution into the corresponding volumetric flask, mix well, cool to a solution temperature of about 40°C, add pyrogallic acid solution (12.10) according to Table 1, dilute to nearly the mark with water, mix well, cool, dilute to the mark with water, mix well. 14.4.7 Let stand for 15 minutes, transfer part of the solution into the corresponding absorption dish according to Table 1, and measure its absorbance at a wavelength of 400nm on a spectrophotometer with water as a reference.
14.4.8 Subtract the absorbance of the blank solution accompanying the sample, and find the concentration of the button from the corresponding working curve according to Table 1. 14.5 Drawing of working curve
14.5.1 Working curve 1
14.5.1.1 Take 0, 0.50, 1.00, 1.50, 2.00, 2.50mL of standard solution (12.13) and place them in a group of 100mL beakers respectively. 14.5.1.2 Add 1g potassium pyrosulfate (12.1), 2g ammonium oxalate (12.2), 1mL phosphoric acid (12.5), and 15mL water to each beaker and heat to dissolve. Transfer the solutions to a set of 50mL volumetric flasks. 14.5.1.3 Add 10mL pyrogallic acid solution (12.10) to the volumetric flask (14.5.1.2), mix well, cool, dilute to the mark with water, and mix well. Let stand for 15 minutes.
14.5.1.4 Transfer part of the solution (14.5.1.3) to 2cm absorption III, use water as reference, and measure its absorbance at a wavelength of 400nm on a spectrophotometer.
14.5.1.5 Subtract the absorbance of the reagent blank solution, and draw a working curve with the concentration of the button as the horizontal axis and the absorbance as the vertical axis. 482
14.5.2 Working curve 1
GB/T 1 5076. 1—94
14.5.2.1 Take 0, 0.40, 0.80, 1.20, 1.60, 2.00mL of molybdenum standard solution (12.12) and place them in a group of 100mL beakers respectively. Then operate according to 14.5.1.2~14.5.1.3. 14.5.2.2 Pour part of the solution into 1cm absorption blood, use water as reference, and measure its absorbance at a wavelength of 400nm on a spectrophotometer. Then draw the working curve according to 14.5.1.5. 14.5.3 Working curve II
14.5.3.1 Take 0, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00 ml of molybdenum standard solution (12.12) and place them in a group of 100 ml beakers respectively. Then proceed as in 14.5.1.2. 14.5.3.2 Add 5 ml of pyrogallic acid solution (12.10) to the volumetric flask (14.5.3.1), mix well, cool, dilute to the mark with water, mix well. Leave for 15 min. Then proceed as in 14.5.2.2. 15 Calculation and description of analysis results
The percentage content is calculated as follows:
Ta(%)→: V×10-
Where: c-
The concentration of molybdenum found from the working curve, ug/mL, V—Total volume of test solution, mL;
m—Mass of test material, g.
16 Allowable difference
The difference between the analysis results of laboratories should not be greater than the allowable difference listed in Table 4. Table 4
Molybdenum content
>0.20~0.50
>0. 50~1. 20
>1. 20~3. 00
Additional remarks:
This standard was proposed by China Nonferrous Metals Industry Corporation. This standard was drafted by Ningxia Nonferrous Metals Smelter. This standard method 1 was drafted by Ningxia Nonferrous Metals Smelter. Zhang Lanfen was the main drafter of this standard method 1. This standard method 2 was drafted by Zhuzhou Cemented Carbide Factory. Pan Zhengfei was the main drafter of this standard method 2. X100
From the date of implementation of this standard, the former Ministry of Metallurgical Industry of the People's Republic of China issued the Ministry of Standard YB942 (10) - 78 "Determination of Molybdenum Content in Saw (Paper Chromatography - Pyrogallic Acid Absorbance Method)" shall be invalid.
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