Vietnam: What is the test method for determining TNT explosives qualified for inclusion in the national stockpile?
- Sampling to perform test methods to determine how TNT explosives qualify for inclusion in the national stockpile in Vietnam?
- What are the criteria to be implemented to determine whether TNT explosives qualify for inclusion in the national stockpile in Vietnam?
- What is the methodology for determining whether TNT explosives qualify for inclusion in national stockpiles in Vietnam?
Sampling to perform test methods to determine how TNT explosives qualify for inclusion in the national stockpile in Vietnam?
Regarding the sampling of TNT explosives specified in Subsection 3.1 Section 3 of the National Technical Regulation QCVN 15:2012/BTC on State Reserves for Industrial Explosive Materials - Explosive Trinitrotoluene (TNT) shall be as follows:
Samples were randomly taken at different locations or at different packages in the same batch of TNT, with the number of packages specified in the table below.
Each package takes 0.3 kg, mixes well and then divides according to the principle of quarters to have a representative sample. The sample is divided into 2 equal parts that are preserved according to the regulations for testing:
- 1/2 of the sample used for testing;
- 1/2 of samples for storage at state-designated industrial explosive materials testing laboratories.
The sample retention time is equal to the guaranteed time of TNT explosives.
Specify the number of packages depending on the volume of TNT batch and packaging specifications
Vietnam: What is the test method for determining TNT explosives qualified for inclusion in the national stockpile?
What are the criteria to be implemented to determine whether TNT explosives qualify for inclusion in the national stockpile in Vietnam?
In Section 3 of the National Technical Regulation QCVN 15:2012/BTC, it is necessary to determine according to the following criteria:
- Bonded determination
- Determination of melting temperature
- Acidity determination
- Determination of water content and volatile substances
- Determination of the amount of insoluble residue in acetes
- Determining bioavailability
What is the methodology for determining whether TNT explosives qualify for inclusion in national stockpiles in Vietnam?
In Section 3 of the National Technical Regulation QCVN 15:2012/BTC guiding the method of conducting as follows:
* Bonded determination
The method of determining the bonding of TNT explosives is determined by eye.
* Determination of melting temperature
- Follow the principle of gradually increasing the ambient temperature of the capillary containing the sample to determine the melting temperature until the sample is completely molten. The average temperature at the time the sample begins to melt and has flown completely liquid is the melting point of the sample.
- Method of conduct:
+ Using a porcelain mortar to crush the sample, it is necessary to determine the melting temperature.
+ Seal one end of the glass capillary, the other end is open.
+ Insert the crushed sample into the capillary, use a copper rod to compact the sample in the capillary until the height of the sample compressed in the capillary reaches (1 ÷ 2) mm.
+ Place the capillary containing the sample in the middle cell, 2 white capillaries placed in the remaining 2 blank cells in the measuring unit of the machine.
+ Adjust the lens of the machine so that it is easy to observe the sample in the capillary.
+ Increase the temperature of the machine to 75 0C, then gradually increase the temperature of the machine with a heating rate of 1 0C / min. Observe and record the temperature at the time the sample begins to have liquid flow (T1) and complete liquid flow (T2).
* Determination of acidity
- The acidity of TNT is determined by acid-base titration with the indicator phenolphthalein.
- Method of conduct
+ The 25g TNT scale has been dried to a constant volume with an accuracy of up to 0.1 mg and put in a 250 ml triangle jar. Add to the jar 100 ml of distilled water, stir gently and put the jar in the water heat.
Bring to a constant boil and stir occasionally until the TNT is completely liquid, place on the stove and stir well for another 5 min. Remove the jar from the water heat, stirring with a stirrer until the temperature drops to room temperature.
+ Drip into the mixture (2 ÷ 3) drops of phenolftalein indicator (pay attention not to shake strongly) and use NaOH 0.1 N solution to titrate this solution until the solution turns pale pink (exists about 30 s). Record the volume of 0.1 N NaOH solution consumed during titration.
* Determination of water content and volatile substances
- Follow the principle that the test sample is dried at (60 ÷ 65) 0C for 4 hours. From the mass reduction calculated the water content and volatile substances contained in the sample.
- Method of conduct:
+ The cage box after rinsing is washed with a mixture of K2Cr2O7/H2SO4 solution and distilled water, dried at (100 ÷ 105) 0C for about 1 h, cooled in a dehumidifier of about 30 min. The scale determines the volume of the cage box that has been dried (G1).
+ Weigh 10 g of finely ground sample into the cage box, spread the sample evenly on the bottom of the cage box. Weigh the volume of the cage box and the sample before drying (G2).
+ Dry the sample container in the drying cabinet at (60 ÷ 65) 0C for 4 h, cool in a silicalgel desiccant of about 30 min. The scale determines the volume of the cage box and the sample after drying (G3).
Note: The scales are accurate to 0.1mg
* Determination of the amount of insoluble residue in acetone
- Determine according to the principle that the content of insoluble impurities in the acetone of TNT is determined by the mass method, after dissolution and filtration through a foam filter cup.
- Method of conduct:
+ Prepare a styrofoam filter cup: rinse the styrofoam filter cup with a mixture of K2Cr2O7/ H2SO4 solution, distilled water, hot acid and dried at (100 ÷ 105) 0C for 1 h. Cool the filter cup in a dehumidifier containing silicagel 0.5 h. The scale determines the volume of the styrofoam filter cup that has been dried (G1).
+ Weigh 10 g of crushed TNT (G) explosive sample and put into a styrofoam filter cup. Until the acid has been heated to (40 ÷ 50) 0C for about 1/2 of the volume of the foam filter cup, place the filter cup in a vacuum tank.
Stir gently with a glass chopstick until the TNT dissolves, then open the vacuum pump to suck out all the TNT/acetone solution in the hopper. Continue to use hot acid to rinse glass chopsticks and foam filter cups until a drop of solution from the foam filter cup is dripped onto the watch glass, when the solvent flies away leaving no marks.
+ Lift the foam filter cup from the vacuum pump, dry at (100 ÷ 105) 0C for 1 h, cool in a dehumidifier for about 15 min. The scale determines the volume of foam filter cups and impurities (G2).
Note: The scales are accurate to 0.1mg.
* Determination of viability
The determination of the viability of TNT explosives is carried out in accordance with TCVN 6423:1998 Industrial explosive materials - Determination of the bioavailability of lead bombs (Trauzel method).
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