GB/T 15076.14-1994 Chemical analysis method of tantalum and niobium - Determination of oxygen content GB/T15076.14-1994 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method of tantalum and niobium
Determination of oxygen content
GB/T 15076.14--94
Part I Method 1 Pulse heated gas melting infrared absorption method 1 Subject content and scope of application
This standard specifies the method for the determination of oxygen content in pliers and saws. This standard is applicable to the determination of oxygen content in pliers and saws. Determination range: 0.005%~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 3 Principle of the method
The sample is melted at high temperature in an inert gas flow and graphite crucible, and oxygen is reduced to carbon monoxide and released. The inert gas is carried by an infrared absorption detector for measurement.
4 Reagents and materials
4.1 Nickel foil: oxygen content less than 0.001%, thickness 0.02~0.05mm. 4.2 Argon: purity greater than 99.99%.
4.3 Oxygen-containing molybdenum and saw standard samples, no less than two (different contents). 4.4 Graphite crucible: made of spectrally pure graphite, shape and size refer to Figure 1. Approved by the State Administration of Technical Supervision on May 9, 1994 and implemented on December 1, 1994
5 Instruments
GB/T15076.14—94
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Pulse heating inert gas melting-infrared absorption oxygen analyzer should meet the following indicators: pulse furnace heating temperature is higher than 3000C, sensitivity is about 0.5μg; drift is not more than 5%; the linear range of the detector is not less than 0~300μg. The schematic diagram of the gas path is shown in Figure 2.
1--gas; 2, 9--regulating valve, 3--deoxidizer; 4, 10--alkali asbestos; 5, 11--phosphorus pentoxide or magnesium perchlorate tube; 6, 16--flowmeter; 7, 8, 12, 15--solenoid valve, 13--pulse heating furnace; 14--dust collector; 17--infrared detector
6 Sample
6.1 Block and filament laboratory samples are made into small particles, washed with acetone or carbon tetrachloride, and air-dried. 6.2 Powdered laboratory samples are wrapped with nickel foil. 7 Analysis steps
7.1 Determination quantity
Weigh 3 samples, analyze them independently, and take the average value. 7.2 Test material
Weigh the samples according to Table 1, accurate to 0.0001g. 538
7.3 Blank test
Specimen type
Block, filament
GB/T 15076.14-94
Test material, g
0. 100 0 ~0. 250 0
Determine the blank value according to the same conditions and steps as the test sample analysis, repeat 3 times, and take the average value, which should not be greater than 51g. 7.4 Instrument calibration
7.4.1 Take a standard sample (4.3) with an oxygen content similar to that of the sample being tested, and operate according to the analysis conditions and steps of the sample, repeat 3 times, calculate the calibration coefficient according to formula (1), and take the average value. K-
Where: K is the mass of oxygen equivalent to the infrared absorption counts per unit: A. infrared absorption counts measured by the standard sample; B. infrared absorption counts measured by the blank test; C. ——The percentage of oxygen in the standard sample; ma-
The mass of a standard sample.
7.4.2 Take another standard sample (4.3) with an oxygen content similar to that of the sample to be tested and conduct verification analysis under the same conditions and steps as the sample analysis. The absolute value of the difference between the obtained result and its standard value should not be greater than the standard allowable difference. 7.5 Determination
7.5.1 Turn on the instrument power supply, pass fluorine gas, adjust the gas flow to 500mL/min, and after the instrument is stable, pass cooling water to the pulse furnace. 7.5.2 Put the sample into the sampler.
7.5.3 Place the graphite crucible in the pulse furnace and heat it for 15s with a current of 900~950A for degassing. 7.5.4 Put the sample into the graphite crucible and heat it for 12s with a current of 900A for analysis, and read the infrared absorption count. 8 Calculation and expression of analysis results
Calculate the percentage of oxygen according to formula (2):
(AB)XK
Wherein: A——the infrared absorption counts obtained by the test sample; B——the infrared absorption counts obtained by the blank test; K is the correction factor obtained by formula (1)?g/unit count; m——the mass of the sample, g.
The result should be expressed to 3 decimal places; if the oxygen content is less than 0.01%, it should be expressed to 4 decimal places. 9 Allowable difference
The difference between the analysis results of different laboratories should not be greater than the allowable difference listed in Table 2. 539
Oxygen content
0. 005 0 ~~0. 008 0
>0. 008 0~0. 020
>0. 020~0. 050
GB/T 15076.14—94
Part II Method 2 Pulse Heated Gas Melting-Coulometric Titration Subject Content and Scope of Application
This standard specifies the method for determining the oxygen content in molybdenum and saw. This standard is applicable to the determination of the oxygen content in molybdenum and saw. Determination range: ≥0.05%~0.6%. 11 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 12 Principles of the method
The sample is melted at high temperature in a fluorine gas flow and graphite crucible, and oxygen is reduced to carbon monoxide, which is converted into carbon dioxide through copper oxidation and reacts with a barium perchlorate absorption liquid with a pH value of about 9.5 to reduce the pH value. The pH value of the absorption liquid is restored by electrolysis. The oxygen content is calculated by counting the amount of electricity consumed by electrolysis.
13 Reagents and materials
13.1 Copper oxide, filamentous, burned in an oxygen flow at 900℃ for 1.5 to 2.0h before use. 13.2 Carbonic acid.
13.3 Perchloric acid wash solution (1+19).
13.4 Solution in the main cup (cathode pool): weigh 50g of crystalline barium perchlorate {Ba(C10)2·3H,0), dissolve in 1000mL of double distilled water, add 30mL of isopropanol, and mix well.
13.5 Solution in the secondary cup (anode pool): weigh 50g of crystalline barium perchlorate, dissolve in 250mL of double distilled water, and mix well. 13.6 Solution in the small cup (reference electrode pool): weigh 5g of crystalline barium perchlorate and 3g of sodium chloride and dissolve in 100mL of double distilled water. After dissolving, add a few drops of silver nitrate solution (50g/L), heat to 60-70℃, cool, and take the supernatant for later use. 13.7 Nickel foil: clean with carbon tetrachloride and blow dry. 13.8 Argon: purity greater than 99.99%.
13.9 Standard samples of oxygen-containing molybdenum and saw.
13.10 Graphite electrode: Spectral pure graphite electrode. See Figure 3 for shape and size.540
14 Instrument
Pulse heating inert gas melting-
GB/T15076.14--94
-Coulomb oxygen analyzer: It consists of two parts: pulse heater and coulomb analyzer. Pulse furnace heating temperature: higher than 3000℃. Sensitivity: 0.5μg.
Gas path flow chart is shown in Figure 4.
1--Fluorine gas cylinder; 2-pressure reducing valve; 3--pressure gauge; 4-copper or copper oxide purification furnace; 5-alkali asbestos purifier; 6phosphorus pentoxide dryer: 7, 8, 9--needle valve; 10, 11, 12---solenoid valve; 13PH solenoid valve: 14-pulse furnace; 15-dust trap; 16 degassing flowmeter: 17·buffer; 18-copper oxide conversion furnace, 19, 20 stop valve 21--analysis flowmeter; 22--absorption cell; 23-argon shield flowmeter 15 Sample
15.1 Powdered laboratory samples are wrapped with nickel box. 15.2 Block and filamentary laboratory samples are made into the required shape, cleaned with carbon tetrafluoride and blown dry. 16 Analysis steps
16.1 Determination quantity
GB/T 15076.14--94
Weigh 3 samples, measure them independently, and take the average value. 16.2 Test material
Weigh the samples according to Table 3, accurate to 0.0001g. Table 3
Specimen type
Block, filament
16.3 Blank test
Test material, name
0. 100 0~ 0.250 0
According to the sample analysis steps and the conditions of the test sample box, measure the blank three times continuously and take the average value, which shall not be greater than 15ug. 16.4 Calibration test
16.4.1 "End point positioning calibration
Perform "end point positioning" calibration on the main cup absorption liquid to make the pH value of the absorption liquid around 9.5. 16.4.2 Electric quantity calibration
A constant current source passes 1 coulomb of electricity through the absorption liquid. During electrolysis, the count should be 166±2, and each count is equivalent to 0.5×10-g oxygen.
16.4.3 Standard sample calibration
Measure the oxygen-containing standard sample under the same conditions as the test sample. The absolute value of the difference between its value and the standard value shall not be greater than the standard sample allowable difference. 16.5 Determination
16.5.1 Introduce argon gas, adjust the pressure gauge to about 9.8×10°Pa, the analytical gas flow rate is 240mL/min, and the fluorine bottle flow rate is 100mL/min.
Turn on the power supply for heating, so that the temperature of the purification furnace and the converter is about 600℃, and the system cold blank is not more than 2 electrical counts per minute. Cooling water is passed through the pulse furnace.
16.5.2 Place the graphite crucible in the pulse furnace for high-temperature degassing. 16.5.3 Place the sample (16.2) in the sampler, put it into the graphite crucible, and perform pulse heating. Refer to the conditions for determination in Table 4. When the system returns to the original blank, read the electrical count. Table 4
Tantalum, saw block, wire
17Calculation and expression of analysis results
Heating current
Calculate the percentage of oxygen according to the following formula:
Heating time
O(%)=(AB)×0. 5×10 *g
Wherein: A—the electrical count obtained when measuring the sample; B—the electrical count obtained when measuring the blank
The mass of the sample, g;
0.5×106——the mass of oxygen corresponding to each electrical count, g. 542
Argon gas flow rate
mL/min
180~240
180~240
180~240
Sample amount
0. 100 0 ~0. 250 0
GB/T15076.14—94
The result should be expressed to 2 decimal places; if the oxygen content is less than 0.1%, it should be expressed to 3 decimal places. 18 Allowable difference
The difference between the analysis results of different laboratories should not be greater than the allowable difference listed in Table 5. Table 5
Oxygen content
>0. 050~0. 10
>0. 10~0. 20
>0. 20~~0. 40
>0. 40~0. 60
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 Ningxia Nonferrous Metals Smelter.
The drafters of Method 1 of this standard are Tian Kongquan and Wang Shulan; the drafters of Method 2 are Wang Shulan and Tian Kongquan.
From the date of implementation of this standard, the former Ministry of Metallurgical Industry of the People's Republic of China Standard YB942 (6)-78 "Determination of oxygen content in molybdenum and sawdust (vacuum melting-
gas chromatography)" shall be invalid.
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