This standard specifies the determination method of phosphorus content in niobium. This standard is applicable to the determination of phosphorus content in niobium, the determination range is: 0.001% ~ 0.05%. GB/T 15076.7-1994 Chemical analysis method of tantalum and niobium Determination of phosphorus content in niobium GB/T15076.7-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method of molybdenum saw
Determination of phosphorus content in niobium
Methods for chemical analysis of tantalum and niobium--Determination of phospherus content in niobium1 Subject content and scope of application
This standard specifies the method for determining the phosphorus content in saws. This standard is applicable to the determination of phosphorus content in mirrors, with a determination range of 0.001% to 0.05%. 2 Reference standards
GB1.4 Guidelines for standardization work Provisions for the preparation of chemical analysis method standards GB1467 General principles and general provisions for chemical analysis method standards for metallurgical products GB7729 General principles for spectrophotometric methods for chemical analysis of metallurgical products 3 Principle of the method
GB/T 15076.7-94
The sample is dissolved in nitric acid and hydrofluoric acid, and potassium fluoride is formed with potassium nitrate. Phosphorus reacts with ammonium in a medium containing nitric acid and hydrofluoric acid (Lc(HNO,)=0.9mol/L,c(HF)=0.07mol/L] to form phosphomolybdic heteropoly acid, which is extracted with 4-methyl-pentanone-[2] and reduced to phosphomolybdic blue with stannous chloride. Its absorbance is measured at a wavelength of 625nm on a spectrophotometer. 4 Reagents
4.1 Nitric acid (pl.42g/mL).
4.2 Hydrofluoric acid (p1.14g/mL).
4.3 4-Methyl-pentanone-[2] (MIBK). 4.4 Sulfuric acid (1+17).
4.5 Potassium permanganate solution (20g/L).
4.6 Potassium nitrate solution (200g/L). bZxz.net
4.7 Sodium nitrite solution (100g/L).
4.8 Ammonium hydroxide solution (100g/1).
4.9 Leaching solution: Take 60mL nitric acid (4.1) in a plastic bottle, add 3mL of newly opened hydrofluoric acid (4.2), and add water to 1000mL. The acidity of the leaching solution is Lc(HNO,)0.9mol/L, c(HF)=0.07mol/L). 4.10 Niobium solution: Weigh 1.000g of metal saw powder (without phosphorus) in a 100mL platinum dish, add 10mL nitric acid (4.1), and add 5ml of hydrofluoric acid (4.2) in batches to completely dissolve the saw powder. Add 10mL potassium nitrate solution (4.6) and mix with a spoon. Place in a boiling water bath and evaporate the solution until there is no mobile liquid phase. The salts are transparent and crystalline. Remove the platinum blood, add 100mL of leaching solution (4.9), stir with a plastic rod to completely dissolve the salts, and transfer to a polyethylene bottle. Prepare on the same day.
GB/T 15076.7-94
4.11 Stannous chloride solution (20g/L): weigh 1g of stannous chloride (SnCl2·2H20) and place it in a 100mL beaker, add 25mL of hydrochloric acid (2+1), heat to dissolve, cool, add water to 50mL, and mix. Prepare on the spot when used. 4.12 Phosphorus standard stock solution: Weigh 0.4264g of diammonium hydrogen phosphate (reference reagent) that has been pre-dried at 105C for 1h and cooled to room temperature in a desiccator, place it in a 200mL beaker, add 50mL of water to dissolve, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix well. This solution contains 100pg phosphorus in 1mL.
4.13 Phosphorus standard solution: Transfer 10.00mL of phosphorus standard stock solution (4.12) to a 100mL volumetric flask, dilute to scale with water, and mix well. This solution contains 10μg phosphorus in 1mL.
5 Instruments
Spectrophotometer.
6 Analysis steps
6.1 Determination quantity
Weigh two samples, measure them independently, and take the average value. 6.2 Test sample
Weigh 0.1g of the sample, accurate to 0.0001g. 6.3 Blank test
Perform a blank test with the test sample.
6.4 Determination
6.4.1Place the test sample (6.2) in a 30mL platinum crucible, add 1mL of nitric acid (4.1), and add a total of 0.5ml of hydrofluoric acid (4.2) dropwise. After the violent reaction stops, place the crucible in a boiling water bath and heat until the test sample is completely dissolved. Add potassium permanganate solution (4.5) dropwise until the solution turns purple-red and continues to heat for 1min. Remove the crucible, add 1mL of potassium nitrate solution (4.6), and add sodium nitrite solution (4.7) dropwise until the test solution is colorless. Continue to evaporate the test solution on the water bath until there is just no mobile liquid phase and the salts are transparent crystals, then remove the crucible. 6.4.2 Add 10mL of leaching solution (4.9) to the crucible, stir with a plastic rod to completely dissolve the salts, transfer the test solution to a 25mL volumetric flask, wash the crucible twice with 10mL of leaching solution (4.9), add the washing solution to the volumetric flask, dilute to the scale with leaching solution (4.9), and mix well. Transfer the test solution to a 60mL separatory funnel according to Table 1, and add leaching solution (4.9) to 20mL. Table 1
Phosphorus content
0.001~0.010
>0. 010~0. 020
>0. 020~0. 030
≥0.0300.040
>0. 040~0. 050
Volume of test solution
Niobium solution
6.4.3 Add 3mL of ammonium sulfate solution (4.8) to the separatory funnel, mix well, and let stand for 5min. Add 10.00mL of MIBK (4.3), shake for 1min, and let stand to separate. Discard the aqueous phase. Add 5mL of sulfuric acid (4.4), shake 10~15 times, let stand to separate, and discard the aqueous phase. The following operations must be performed below 25 (hours.
6.4.4 Add 2mL of stannous chloride solution (4.11) to the separatory funnel (6.4.3), shake 10 times. Leave for 10 minutes, and remove the aqueous phase. Immediately transfer part of the organic phase to a 1cm dry absorption dish, and measure its absorbance at a wavelength of 625nm using MIBK as a reference on a spectrophotometer. Note: The color development batch needs to be controlled to ensure that this operation is completed within 5 minutes. 6.4.5 Subtract the absorbance of the blank solution accompanying the sample and find the corresponding phosphorus amount from the working curve. 509
6.5 Drawing of working curve
GB/T 15076. 7-94
6.5.1 Take 0, 0.05, 0.10, 0.20, 0.40, 0.60, 0.80, 1.00 mL of phosphorus standard solution (4, 13) and place them in a set of 60 mL separatory funnels respectively. Add the ion solution (4.10) according to Table 1 and add the leaching solution (4.9) to 20 mL. Follow the steps in 6.4.3 and 6.4.4. 6.5.2 Subtract the reagent blank Absorbance, with phosphorus as the horizontal axis and absorbance as the vertical axis, draw a working curve. 7 Calculation and expression of analysis results
Calculate the percentage of phosphorus according to the following formula:
P(%)=mV×10-6
Where: mt--—phosphorus amount found from the working curve, μg; V.—total volume of test solution, mL;
V——volume of test solution taken, mL;
mu-—— The mass of the test material, g.
8 Allowable difference
The difference in the analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
Phosphorus content
0. 0010~0. 0050
>0. 005~ 0. 012
>0. 012~0. 050
Additional remarks:
This standard is proposed by China Nonferrous Metals Industry Corporation. This standard is drafted by Ningxia Nonferrous Metals Smelter. This standard is drafted by Beijing Nonferrous Metals Research Institute. The main drafter of this standard is Shi Qingzhang.
Allowable difference
From the date of implementation of this standard, the former Ministry of Metallurgical Industry of the People's Republic of China Standard YB942 (12)-78\Determination of phosphorus content in sawdust (ethyl acetate extraction spectrophotometry)" shall be invalid. 510
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