GB/T 4324.29-1984 Chemical analysis of tungsten - Gravimetric determination of the amount of residue after chlorination and volatilization GB/T4324.29-1984 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method of tungsten
Gravimetric method for the determination ofresidue content after chlorination and volatilization
Methods for chemical analysis of tungstenThe gravimetric method for the determination ofresidue content after chlorination and volatilizationLDC 669.27:543
GB 4324.29--84
This standard is applicable to the determination of the residue content after chlorination and volatilization in tungsten oxide, tungsten powder and carbide. Measurement range: 0.02～0.20%. This standard complies with (B1467-78 "General Principles and General Provisions of Chemical Analysis Methods for Metallurgical Products". 1 Method Summary
The sample is passed through hydrogen chloride gas at 750-800℃ to make the volatile components escape and then the residual content is determined by gravimetric method. 2 Reagents and materials
2.1 Sulfuric acid (specific gravity 1.84).
2.2 Hydrochloric acid-sodium chloride mixture: 2 parts hydrochloric acid (specific gravity 1.19) and 1 part sodium chloride are mixed according to the mass ratio. 3 Instruments
The schematic diagram of the device for determining the residual amount after chlorination is shown in the figure below. 1 Hydrogen monoxide gas generator, 2 integrated buffer plug; * 3 integrated drying bottle (containing concentrated sulfuric acid) 4 integrated flow meter, 5 flask (or nest flask) height 10mm, 1 width 15mm, bottom width 10mm,: 1 length 85mm, bottom 80mm: 6 type protection: effective length is about 300mm: 7-quartz reaction piece diameter 19-20mm, length t50mm, 8-thermocouple high temperature
4 Analysis steps
4.1 Determination quantity
When analyzing, weigh a sample for determination. The measured value should be within the allowable difference, and the average value should be taken. 4.2 Sample quantity
Weigh 3000~5.000g sample.
Powder and carbonized pigeon should be burned at 750~800℃ to become tungsten trioxide. National Bureau of Standards 19840412 Issued
1985-03-01 Implementation
4. 3 Determination
GB 4324.29--B4
4.3.1 Turn on the electric tube furnace (6) to heat the quartz reaction tube (7); make the temperature rise and maintain it at 750~800C. .32·Put the sample (4.2) in a platinum boat or a quartz boat (5), open the separating funnel of the hydrogen chloride gas generator [pre-filled with sulfuric acid (2.1)], add sulfuric acid dropwise to the conical flask pre-filled with a mixture of hydrochloric acid and sodium oxide, and adjust the flow rate of the hydrogen chloride gas to about 250ml/min, and pass it through a gas drying bottle pre-filled with concentrated sulfuric acid. Push the platinum boat containing the sample into the high temperature area of ​​the reaction tube, and connect the ammonium fluoride gas to allow the volatile components to escape. 4.3.3. After 1.5 to 2 hours from the start of chlorination to the completion of chlorination, unplug the reaction tube, immediately pull the platinum boat to the low temperature area, cool it slightly (do not leave the platinum boat in the high temperature area without hydrogen gas), take it out, and place it in a desiccator (if the residue absorbs water seriously, take it out from the reaction tube The platinum boat can be immediately loaded into a pre-dried glass casing with a ground stopper, plugged with a ground stopper, placed in a desiccator, cooled to room temperature, and weighed together with the glass tube), cooled to room temperature, and weighed (to ensure complete chlorination, the original platinum boat can be pushed back into the high temperature area of ​​the reaction tube after weighing, and nitrided with hydrogen peroxide gas for 15 minutes. After the gas is stopped, the platinum boat is immediately pulled to the low temperature area, cooled slightly and taken out, placed in a desiccator and cooled to room temperature, and weighed. Repeat this operation until constant weight is obtained). ||tt| |4.3.Put the platinum boat with residue in water and boil for 5mm, take it out, cool it, wash it, rinse it with distilled water and wipe it, put it in the original reaction tube and burn it for 5min, take it out, put it in a desiccator, cool it to room temperature, and weigh it (the empty platinum boat can also be repeatedly washed, burned and weighed until the weight is constant).
Calculation of analysis results
Calculate the white content of the residue after chlorination and volatilization according to the following formula: batch
Residue after chlorination and volatilization (%)
Formula: m,-
Allowable difference
Mass of chlorinated residue and platinum boat, name,
Mass of platinum boat, g,
Sample size,bZxz.net
The difference in analysis results between experimental baskets should not be greater than the allowable difference listed in the table below. Residue after chlorination and volatilization
0.02--0.05
>0.05~0.12
>0.12～0.20
Additional remarks:
This standard is proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard is drafted by Zhuzhou Cemented Carbide Factory.m
Allowance
The main drafter of this standard is Wang Jishen.
From the date of implementation of this standard, the original standard YB895-77 "Chemical Analysis Method of Tungsten" of the Ministry of Metallurgical Industry will be invalid.102
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