GB/T 4324.14-1984 Chemical analysis of tungsten - Determination of calcium content by atomic absorption spectrophotometry GB/T4324.14-1984 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method of tungsten
Atomic absorption spectrophotometric method for the determination of calcium contentUDC 669.27 :543
. 42 : 546. 41
GB4324.14—84
This standard is applicable to the determination of calcium content in calcium powder, tungsten strips, tungsten trioxide, tungsten acid and ammonium tungsten acid. The determination range is 0.0007～0.030%. This standard complies with GB1467-78 "General test rules and general provisions of chemical analysis method standards for metallurgical products". Method summary
The sample is decomposed with hydrogen peroxide, and a certain amount of potassium sodium tartrate is added as a complexing agent. In an ammonia medium, calcium is extracted with 8-hydroxyquinoline in an alcohol solution. The organic atom absorbs at a wavelength of 422.7nm using an oxygen-air-acetylene flame to determine calcium.
2 Reagents
: 2.1 Ammonium hydroxide (specific gravity 0.90), extra pure. 2.2 Hydrogen peroxide (specific gravity 1.10), premium pure. 2.3 8-Hydroxyquinoline in an alcohol solution: Weigh 1.5g of 8-hydroxyquinoline and dissolve it in 100ml of an alcohol solution and mix. 2.4 Potassium sodium tartrate solution (30%)
The purification method is as follows: Take 300 ml of potassium sodium tartrate solution (30%), cover it in a 500 ml separatory funnel, add 6 ml of sodium hydroxide solution (20%) and 50 ml of 8-hydroxyquinoline n-1-alcohol solution (3%), extract and shake for 5 minutes, let it stand to separate the layers, and transfer the aqueous phase to another 500 ml separatory funnel. Use the same method to extract again, and then use 1% alcohol to extract and wash several times (50 ml of n-1-alcohol each time) until the yellow color of the solution disappears. Store the purified potassium sodium tartrate solution in a plastic container for later use. 2.5 Calcium standard solution
2.5.1 Take 2.4970g of calcium carbonate (99.90%) which has been dried at 105℃ for 1h and cooled to room temperature in a desiccator, place it in a 300ml beaker, add 20ml of water, dissolve it with 20ml of hydrochloric acid (1+1), add 10ml, boil to remove carbon dioxide, cool, transfer to a 1000ml volumetric flask, dilute to scale with water, and mix. This solution contains 1.0mg calcium in 1ml. 2.5.2 Take 10.00ml of calcium standard solution (2.5.1), cover a 100ml volumetric flask, dilute to scale with water, and mix. This solution contains 100μg calcium in 1ml.
3 Instrument
Original absorption spectrophotometer. Equipped with a sample shielded air-acetylene water-cooled burner and a calcium cathode lamp. The absorption spectrophotometer used should meet the following indicators. Minimum sensitivity: 1. The absorbance of the highest concentration standard solution of the equidistant concentration standard solution used in the curve drawing should not be less than 0.250. [Linearity of curve drawing: "Among the equidistant concentration standard solutions used in the curve drawing, the difference in absorbance between the highest and second highest concentration standard solutions should not be less than 10.9 of the absorbance value of the lowest concentration standard solution minus the zero concentration solution. Minimum stability: 1. The absorbance obtained by multiple measurements of the highest concentration standard solution and the zero concentration solution used in the curve drawing, relative to the average absorbance of the highest concentration standard solution, should have a coefficient of variation of less than 1.5% and 0.6%, respectively. For the calculation of the minimum stability coefficient of variation, see GB promulgated by the National Bureau of Standards on April 12, 1984 and implemented on March 1, 1985. 4324.14—84
Appendix A (supplement).
The operating conditions and parameters of the H-700 modified original f-absorption spectrophotometer are shown in Appendix B (reference number). Sample
The pigeon strips should be crushed and passed through a 120 self-sieve.
Analysis steps
Measurement quantity
During analysis, a sample should be weighed for measurement, and the measurement should be within the room allowable error, and the average value should be taken. 52 Sample quantity
Take the sample according to the length
Sample
Blank test
Carry out a blank test with the commercial sample.
5. 4 Determination
0.001~0.010
0.010~0.020
20.020~0.030
5.4.1 Pigeon powder, tungsten bar, tungstic acid, ammonium paratungstate 5.4.11 Place the sample (5.2) in 100ml of burnt pine, drop 3~5ml of hydrogen peroxide (2.2), place it on an electric furnace for low-heat decomposition, and remove it after the sample is dissolved.
5.4.1.2 Add 2~3ml of potassium sodium tartrate solution (2.4), place it on an electric furnace and heat it until the solution is clear, drop 2ml of ammonium hydrocyanide (2.1, boil, remove and cool.||tt ||5.4.h.3 Add 15ml of ammonium hydroxide (2.1) and transfer it to a 100ml separatory funnel, add 10ml of 8-hydroxyguanidine alcohol solution (2.3), stir for 5min, let stand to separate, and discard the aqueous phase. 5.4.1.4 Place the organic phase on an absorption spectrophotometer at a wavelength of 422.7nm, shield the air-acetylene flame with oxygen, and adjust the temperature with water to measure the absorbance of calcium, and find the corresponding calcium concentration from the working curve. 5.4.2
Oxidation
Put the sample in a 100ml beaker, add 2~3ml of acid-free steel paint solution (2.4), add 10~2 0ml ammonium hydroxide (2.1), heat on the electric furnace to dissolve the sample, remove and cool. The following is carried out according to 5.4.1.3~5.4.1.4. 5.5 Drawing of working curve
5.5.1 Take 0.00, 0.10, 0.20, 0.30, 0.10, 0.50ml calcium standard solution (2.5.2), respectively put it in a pure 100ml separatory funnel, add 5ml water, 15ml ammonium hydroxide (2.1), 10ml 8-hydroxybenzoic acid alcohol solution (2.3), mix each reagent, extract and shake for 5min, stand and separate, and remove the aqueous phase. 5.5.2 Put the organic phase in the original! Absorbance spectrophotometer, F wavelength 422.7nm, use oxygen to shield the air-acetylene flame, adjust to zero with water, and measure the absorbance of calcium. With calcium concentration as the abscissa and absorbance (the absorbance of the alkali-removed reagent blank) as the ordinate, draw a line:
6 Calculation of analysis results
Calculate the percentage of the solution as follows:
ca(%) --
(m2mi)v
:×100
m× 106
GB 4324.14--84
Formula: m2—calcium concentration of the sample solution obtained from the working curve, μg/ml mz—calcium concentration of the blank prepared with the sample obtained from the T curve, μg/ml, total volume of test solution, ml,
—sample volume. g.
Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference shown in Table 2. Table 2
0.0007 -0.0025
0.0025 ~0.0060
>0.006~0.012
0.012~0.016
..016.03
Allowance
GB4324:14—84
Appendix A
Calculation of minimum stability coefficient of variation
(Supplement)
A.1 The formula for calculating the coefficient of variation of the absorbance readings of the highest concentration standard solution and the zero concentration solution is as follows: 100
武: Sc-
2(CC)
E (0-0)2
Percent variation coefficient of absorbance of the highest concentration standard solution, Percent variation coefficient of absorbance of zero concentration solution, - Average value of absorbance of the highest concentration standard solution; - Absorbance of the highest concentration standard solution
Average value of absorbance of zero concentration solution!
Absorbance of zero concentration solution,
Number of measurements.
Additional instructions
GB 4324.14—84
Appendix Bwww.bzxz.net
Working Condition Parameters of H-700 Modified Atomic Absorption Spectrophotometer (Reference)
Lamp Current
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by Zhuzhou Cemented Carbide Factory.
Burner Height
This standard was drafted by Baoji Nonferrous Metals Research Institute and Baoji Nonferrous Metals Processing Plant. The main drafter of this standard is Xu Jinwen.
Air Flow
Acetylene Flow
From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB895--77 "Tungsten Chemical Analysis Method" will be invalid. Wanxiezhi17bzw.cn crispy and simple type of color red mark travel science 5 fin lake
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