Method for rapidly measuring content of black powder in engine ignition powder

Abstract

The invention discloses a method for rapidly measuring the content of black powder in engine ignition powder. According to the characteristics that potassium nitrate in black powder and ignition powder is easily dissolved in water and other components such as carbon, sulfur, magnesium powder and polytetrafluoroethylene resin powder are insoluble in water, water is adopted as an extracting agent, the content of potassium nitrate in the raw material black powder is accurately measured firstly, and then the content of potassium nitrate in the ignition powder is accurately measured; and calculating the content of the black powder in the ignition powder. The method has the advantages of convenient detection process, rapidness, environmental protection, low cost, high detection precision, small error and accurate and consistent detection result.

Description

Technical Field

[0001] The invention belongs to the field of black powder content analysis, and in particular relates to a method for quickly determining the black powder content in engine ignition powder. Background Art

[0002] The engine is the core component of the propulsion system. The main role of the propulsion system ignition powder in the engine is: the ignition powder undergoes combustion reaction to generate high-temperature combustion products. The ignition powder combustion products transfer heat to the propellant surface through heat conduction, convection and radiation heat exchange, igniting the engine propellant, so that the engine starts working. The composition, amount and ratio of the ignition powder are the main factors affecting the ignition energy of the ignition powder.

[0003] The ignition powder is composed of black powder (HY-5, 12g±ag), magnesium powder (5g±bg) and polytetrafluoroethylene resin powder (5g±cg). The specific process is: black powder baking → three components weighing → mixing evenly → wrapping ignition powder package → assembling finished product → finished product inspection. However, during the finished product inspection, since this product is a high-tech product, this type of engine ignition powder has particularity and specificity. In order to standardize the test method, make the test data comparable, guide the manufacture and acceptance of engine ignition powder, and meet the needs of high-tech product production technical indicators, the present invention studies the test method of engine ignition powder components. Summary of the invention

[0004] The invention aims to provide a method for quickly determining the content of black powder in engine ignition powder, which has the advantages of convenient detection process, rapidness, environmental protection, low cost and accurate and consistent detection results.

[0005] The technical solution of the present invention is as follows:

[0006] A method for quickly determining the content of black powder in engine ignition powder comprises the following steps:

[0007] S1. Determination of potassium nitrate content in black powder

[0008] Weigh 1.5000g of black powder sample and place it in a 150mL beaker, add water to make the sample into a paste, add 50-80mL of water to soak for 15-30min, stir, filter with quantitative filter paper into a 250mL beaker with constant weight, wash the residue with water, collect the filtrate and add diphenylamine sulfuric acid solution to check until it does not appear blue; place the beaker containing the filtrate on an electric heater to heat and evaporate the water, then place the beaker in an oven at 100℃~110℃ to dry for 1.5-3h, take out the beaker and place it in a desiccator to cool for 20-40min, weigh until constant weight, take the last measured value as the measurement result, and get the total mass of the beaker and potassium nitrate;

[0009] The potassium nitrate content is expressed as mass fraction w (KNO3), and the value is expressed in %, calculated according to formula (1):

[0010]

[0011] Where:

[0012] m3 is the mass of the hollow beaker S1, in grams (g);

[0013] m4-the value of the mass of the beaker and potassium nitrate in S1, in grams (g);

[0014] m2 is the numerical value of the mass of the black powder sample, in grams (g);

[0015] ω(KNO3) is the mass fraction of potassium nitrate in black powder, expressed in %.

[0016] S2. Determination of potassium nitrate content in ignition powder

[0017] Weigh 3.0000g of sample and place it in a 150mL beaker. Add water to mix the black powder in the ignition powder into a paste. Add 50-80mL of water to soak for 15-30min, stir, filter with quantitative filter paper into a 250ml beaker with constant weight, wash the residue with water, collect the filtrate and add diphenylamine sulfuric acid solution to check until it does not appear blue; place the beaker containing the filtrate on an electric heater to heat and evaporate the water; then place the beaker in an oven at 100℃~110℃ to dry for 1.5-3h, take out the beaker and place it in a desiccator to cool for 20-40min, weigh until constant weight, take the last measured value as the measurement result, and get the total mass of the beaker and potassium nitrate;

[0018] S3. Result calculation

[0019] The black powder content is expressed as mass fraction ω(HY), and the value is expressed in %, calculated according to formula (2):

[0020]

[0021] Where:

[0022] m6-S2 is the numerical value of the mass of the hollow beaker, in grams (g);

[0023] m7-The value of the mass of the beaker and potassium nitrate in S2, in grams (g);

[0024] m5 is the value of the sample mass, in grams (g);

[0025] ω(KNO3) is the mass fraction of potassium nitrate in black powder, expressed in %.

[0026] Furthermore, in S1 and S2, the amount of soaking water is preferably 50 to 60 ml.

[0027] Furthermore, in S1 and S2, the filtrate is collected using a drip plate.

[0028] Furthermore, in S1 and S2, the mass fraction of the diphenylamine sulfuric acid solution is 0.1% to 0.2%, preferably 0.1% to 0.15%.

[0029] Furthermore, the diphenylamine sulfuric acid solution is prepared by dissolving diphenylamine in concentrated sulfuric acid. For example, 0.2 g of diphenylamine is dissolved in 100 mL of concentrated sulfuric acid to prepare the diphenylamine sulfuric acid solution.

[0030] Furthermore, in S1 and S2, the electric heaters used are continuously adjustable.

[0031] Furthermore, in S1 and S2, the drying temperature is preferably 105°C to 110°C.

[0032] Furthermore, in S1 and S2, the drying time is preferably 2 to 2.5 hours.

[0033] Furthermore, in S1 and S2, the cooling time is preferably 25 to 30 minutes.

[0034] The beneficial effects of the present invention are:

[0035] (1) The present invention only needs water as an extractant. By first determining the potassium nitrate content in the raw material black powder and then determining the potassium nitrate content in the ignition powder, the black powder content in the ignition powder can be calculated. This method is first introduced in China and is simple, effective and technically stable.

[0036] (2) The detection process of the present invention is convenient, rapid, environmentally friendly, low in cost, high in detection accuracy, small in error, and the detection results are accurate and consistent. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below with reference to specific embodiments, but the present invention is not limited thereto.

[0038] Example 1

[0039] Method for detecting the content of black powder in engine ignition powder: 1 Principle

[0040] Black powder is composed of potassium nitrate, carbon and sulfur. Only potassium nitrate can be dissolved in water. Therefore, water can be used to extract the potassium nitrate in the sample, weigh it, and calculate the black powder content in the ignition powder.

[0041] 2 Reagents and materials

[0042] 2.1 The water used in the laboratory should meet the specifications of Grade III water in GB / T 6682.

[0043] 2.2 Sulfuric acid: H2SO4, GB / T625.

[0044] 2.3 Diphenylamine: (C6Hs)2NH, GB / T 681.

[0045] 2.4 Diphenylamine sulfuric acid solution: Weigh 0.2 g of diphenylamine and dissolve it in 100 mL of sulfuric acid.

[0046] 2.5 Color-changing silica gel: HG / T 2765.4.

[0047] 2.6 Medium-speed quantitative filter paper: GB / T 1914.

[0048] 3. Instruments, equipment and test equipment

[0049] 3.1 Analytical balance: graduation value 0.1 mg.

[0050] 3.2 Continuously adjustable electric heater.

[0051] 3.3 Oven: Maximum temperature 200℃, control accuracy ±2℃.

[0052] 3.4 Dryer: diameter 180mm~240mm, filled with color-changing silica gel.

[0053] 3.5 Funnel: diameter 70mm~80mm.

[0054] 3.6 Funnel rack: two holes or multiple holes.

[0055] 3.7 Beaker: 150mm, 250mm.

[0056] 3.8 Drip board.

[0057] 3.9 dropper.

[0058] 4. Sample preparation

[0059] Place a sample of ignition powder (about 22g) in a mortar and grind it carefully and evenly, put it into a weighing bottle, and place it in a desiccant-free dryer for later use.

[0060] 5. Determination Procedure

[0061] 5.1 Determination of potassium nitrate content in black powder

[0062] Weigh 1.5g (accurate to 0.0001g) of black powder (black powder used in ignition powder preparation) sample and place it in a 150mL beaker, add a small amount of water to make the sample into a paste, add 50mL water to soak for 20min, stir, filter with quantitative filter paper into a 250mL beaker with constant weight, wash the residue with water, collect the filtrate with a drip plate, add diphenylamine sulfuric acid solution (0.2g diphenylamine dissolved in 100mL concentrated sulfuric acid) and check until it does not appear blue. Place the beaker containing the filtrate on a continuously adjustable electric heater to heat (after the solution boils, the heating temperature should not be too high) and evaporate to near dryness. Place the beaker in an oven at 105℃~110℃ to dry for 2h, take out the beaker and place it in a desiccator to cool for 30min, weigh until constant weight (the so-called constant weight means that the difference between the results of two consecutive weighing operations is not greater than 0.0003g), and take the last measured value as the measurement result.

[0063] The potassium nitrate content is expressed as mass fraction w(KNO3), the value is expressed in %, and is calculated according to formula (1).

[0064]

[0065] Where:

[0066] m3 is the mass of the empty beaker in grams (g);

[0067] m4 is the value of the mass of the beaker and potassium nitrate, in grams (g);

[0068] m2 is the numerical value of the mass of the black powder sample, in grams (g);

[0069] ω(KNO3) is the mass fraction of potassium nitrate in black powder, expressed in %.

[0070] 5.2 Determination of potassium nitrate content in ignition powder

[0071] Weigh 3.0g (accurate to 0.0001g) of the sample and place it in a 150mL beaker. Add a small amount of water to make the black powder in the ignition powder into a paste. Add 50mL of water to soak for 20min, stir, filter with quantitative filter paper into a 250ml beaker with constant weight, wash the residue with water, collect the filtrate with a drip plate, add diphenylamine sulfuric acid solution (0.2g diphenylamine dissolved in 100mL sulfuric acid) and check until it does not appear blue. Place the beaker containing the filtrate on a continuously adjustable electric heater to heat (after the solution boils, the heating temperature should not be too high) and evaporate to near dryness. Place the beaker in an oven at 105℃~110℃ to dry for 2h, take out the beaker and place it in a desiccator to cool for 30min, weigh until constant weight (the so-called constant weight means that the difference between the results of two consecutive weighing operations is not greater than 0.0003g), and take the last measured value as the measurement result.

[0072] 6 Result calculation

[0073] The black powder content is expressed as mass fraction ω(HY), the value is expressed in %, and is calculated according to formula (2).

[0074]

[0075] Where:

[0076] m6 is the mass of an empty beaker in grams (g);

[0077] m7 is the value of the mass of a beaker and potassium nitrate, in grams (g);

[0078] m5 is the value of the sample mass, in grams (g);

[0079] ω(KNO3) is the mass fraction of potassium nitrate in black powder, expressed in %.

[0080] The ignition powder of a certain engine is composed of black powder (HY-5, 12g±ag), magnesium powder (5g±bg) and polytetrafluoroethylene resin powder (5g±cg), among which black powder is composed of potassium nitrate, carbon and sulfur. Therefore, the ignition powder of a certain engine includes five components: potassium nitrate, carbon, sulfur, magnesium powder and polytetrafluoroethylene resin powder. Through analytical tests, it is found that among the five components of potassium nitrate, carbon, sulfur, magnesium powder and polytetrafluoroethylene resin powder, only potassium nitrate is easily soluble in water, while the four components of carbon, sulfur, magnesium powder and polytetrafluoroethylene resin powder are not soluble in water. The potassium nitrate in the sample can be extracted with water, weighed, and the black powder content in the ignition powder can be calculated.

[0081] The determination method of the present invention shows that the determination result is accurate.

Claims

1. A method for rapidly determining the content of black powder in engine ignition powder, characterized in that: The steps include: S1. Determination of potassium nitrate content in black powder Weigh 1.5000g of black powder sample and place it in a 150mL beaker, add water to make the sample into a paste, add 50-80mL of water to soak for 15-30min, stir, filter with quantitative filter paper into a 250mL beaker with constant weight, wash the residue with water, collect the filtrate and add diphenylamine sulfuric acid solution to check until it does not appear blue; place the beaker containing the filtrate on an electric heater to heat and evaporate the water, then place the beaker in an oven at 100℃~110℃ to dry for 1.5-3h, take out the beaker and place it in a desiccator to cool for 20-40min, weigh until constant weight, take the last measured value as the measurement result, and get the total mass of the beaker and potassium nitrate; The potassium nitrate content is expressed as mass fraction w (KNO3), and the value is expressed in %, calculated according to formula (1): Where: m3 is the mass of the hollow beaker S1, in grams (g); m4-the value of the mass of the beaker and potassium nitrate in S1, in grams (g); m2 is the numerical value of the mass of the black powder sample, in grams (g); ω(KNO3) is the mass fraction of potassium nitrate in black powder, expressed in %. S2. Determination of potassium nitrate content in ignition powder Weigh 3.0000g of sample and place it in a 150mL beaker. Add water to mix the black powder in the ignition powder into a paste. Add 50-80mL of water to soak for 15-30min, stir, filter with quantitative filter paper into a 250ml beaker with constant weight, wash the residue with water, collect the filtrate and add diphenylamine sulfuric acid solution to check until it does not appear blue; place the beaker containing the filtrate on an electric heater to heat and evaporate the water; then place the beaker in an oven at 100℃~110℃ to dry for 1.5-3h, take out the beaker and place it in a desiccator to cool for 20-40min, weigh until constant weight, take the last measured value as the measurement result, and get the total mass of the beaker and potassium nitrate; S3. Result calculation The black powder content is expressed as mass fraction ω(HY), and the value is expressed in %, calculated according to formula (2): Where: m6-S2 is the numerical value of the mass of the hollow beaker, in grams (g); m7-The value of the mass of the beaker and potassium nitrate in S2, in grams (g); m5 is the value of the sample mass, in grams (g); ω(KNO3) is the mass fraction of potassium nitrate in black powder, expressed in %.

2. The method for rapidly determining the content of black powder in engine ignition powder according to claim 1, characterized in that: In S1 and S2, the amount of soaking water is 50 to 60 ml.

3. The method for rapidly determining the content of black powder in engine ignition powder according to claim 1, characterized in that: In S1 and S2, the filtrate was collected using a drip plate.

4. The method for rapidly determining the content of black powder in engine ignition powder according to claim 1, characterized in that: In S1 and S2, the mass fraction of the diphenylamine sulfuric acid solution is 0.1% to 0.2%.

5. The method for rapidly determining the content of black powder in engine ignition powder according to claim 1, characterized in that: In S1 and S2, the mass fraction of the diphenylamine sulfuric acid solution is 0.1% to 0.15%.

6. The method for rapidly determining the content of black powder in the engine ignition powder according to claim 4 or 5, characterized in that: In S1 and S2, the diphenylamine sulfuric acid solution is prepared by dissolving diphenylamine in concentrated sulfuric acid.

7. The method for rapidly determining the content of black powder in engine ignition powder according to claim 1, characterized in that: In S1 and S2, the electric heater used can be continuously adjusted.

8. The method for rapidly determining the content of black powder in engine ignition powder according to claim 1, characterized in that: In S1 and S2, the drying temperature is 105°C to 110°C.

9. The method for rapidly determining the content of black powder in engine ignition powder according to claim 1, characterized in that: In S1 and S2, the drying time is 2 to 2.5 hours.

10. The method for rapidly determining the content of black powder in engine ignition powder according to claim 1, characterized in that: In S1 and S2, the cooling time is 25 to 30 minutes.

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