GB/T 20209-2026Fireworks - Aluminium-magnesium alloy powder (English PDF)

5.2.1 Sieving Method (Arbitration Method)

5.2.1.1 Method Principle A certain amount of sample is placed on a standard sieve and, with the aid of vibration, passes through a standard sieve with a certain mesh size. The amount of material remaining on (below) the sieve is then weighed. The amount of material on (or below) the sieve of that mesh size is used to calculate the content of the material.

5.2.1.2 Equipment and Instruments 5.2.1.2.1 Test sieves. Test sieves shall conform to the requirements of GB/T 6003.1.The sieve frame size is phi200mm×50mm, and the test sieve assembly... The screen aperture range is 24µm (550 mesh) and above. 5.2.1.2.2 Vibrating sieve. An eccentric vibrating sieve vibrating machine (i.e., during the sieve vibrating process, the test sieve can be made to rock in a circular motion and vibrate up and down). (Shaking) The frequency is 290 times/min, and the vibration is 145 times. 5.2.1.2.3 Antistatic soft brush. 5.2.1.2.4 Electronic balance. accuracy 0.0001g. 5.2.1.2.5 Stopwatch. Accuracy is 0.01s.

5.2.1.3 Determination Procedure (Method 1 - Mechanical Sieving Method) 5.2.1.3.1 Select the appropriate test sieve group based on the technical conditions of aluminum-magnesium alloy powder. 5.2.1.3.2 Stir the sample thoroughly and weigh 10.00g of the sample, accurate to 0.0001g. 5.2.1.3.3 Place the sample on the upper sieve, cover it with the pressure cap, and fasten the test sieve group to the vibrating sieve machine. Vibrate for 10 minutes. 5.2.1.3.4 Remove the test sieve group and weigh the aluminum-magnesium alloy powder of the material on the upper sieve and the material under the lower sieve.

5.2.1.4 Determination Procedure (Method 2 - Manual Sieving Method) 5.2.1.4.1 Select the appropriate test sieve group based on the technical conditions of aluminum-magnesium alloy powder. 5.2.1.4.2 Stir the sample thoroughly and weigh 10.00g of the sample, accurate to 0.0001g. 5.2.1.4.3 Place the sample on the upper sieve and gently brush and manually sieve the sample with a clean soft brush. 5.2.1.4.4 After the samples on the upper sieve are sieved, the samples on the lower sieve are manually sieved according to 5.2.1.4.3. 5.2.1.4.5 Remove the test sieve group and weigh the aluminum-magnesium alloy powder of the material on the upper sieve and the material under the lower sieve.

5.2.1.5 Calculation of Measurement Results 5.2.1.5.1 Calculate the mass fraction of aluminum-magnesium alloy powder on the upper sieve according to formula (1). 5.2.1.5.2 Calculate the mass fraction of aluminum-magnesium alloy powder in the undersize material according to formula (2).

5.2.2 Laser Diffraction Method

5.2.2.1 Method Principle When a laser beam irradiates metal powder particles dispersed in a liquid medium, scattering occurs, and particles of different sizes produce unique scattering effects. Characterizing the scattering pattern. The instrument receives scattered light signals through detectors distributed at different angles, and then uses optical theory and mathematical models to analyze these scattered light signals. The optical signal is used to deduce the particle size distribution of the powder sample based on volume.

5.2.2.2 Equipment and Instruments 5.2.2.2.1 Laser Particle Size Analyzer. Suitable for particle size determination of micron-sized samples, equipped with solvent-based or micro-sample cell injection system, providing accurate particle size measurement. The deviation should not be less than 0.5% (D50 deviation of national or international standard). 5.2.2.2.2 Ultrasonic disperser. frequency not less than 15kHz.

5.2.2.3 Reagents and Materials Anhydrous ethanol (AR).

5.2.2.4 Measurement Procedure 5.2.2.4.1 Stir the sample thoroughly, take about 0.3g of the sample into a 50mL beaker, add 20mL of anhydrous ethanol, and ultrasonically disperse until the powder is dispersed. No aggregation was observed, indicating that this is test solution A. 5.2.2.4.2 Set the sample parameters and input the sample information on the operating software according to the instrument's instruction manual. 5.2.2.4.3 Add anhydrous ethanol as the circulating medium, adjust the stirring speed and the injection pump speed, and test the instrument background. 5.2.2.4.4 After measuring an effective background, add test solution A to the injection system using a dropper to make the occlusion 5%~30%. 5.2.2.4.5 Click the "Start" button on the operating software to begin the measurement. 5.2.2.4.6 After the measurement is completed, check and record the results (D10 and D90).

5.2.2.5 Expression of Measurement Results Two results were measured for each sample in parallel, with an allowable difference of no more than 0.2 µm. The arithmetic mean of the results was taken and the results were retained to two decimal places.

5.3 Determination of Aluminum Content

5.3.1 Method Summary The sample was dissolved in hydrochloric acid. Under conditions of pH 2.5-2.8, aluminum and other metal ions complexed with disodium ethylenediaminetetraacetate. When the concentration is 5-6, excess disodium ethylenediaminetetraacetate is titrated with zinc standard solution, then aluminum is replaced with sodium fluoride, releasing a fixed amount of ethylenediamine. The aluminum content was determined by titrating the released ethylenediaminetetraacetic acid disodium salt with a zinc standard solution.

5.3.2 Reagents and Materials

5.3.2.1 Hydrochloric acid (1 4).

5.3.2.2 Ammonia (1 4).

5.3.2.3 Disodium ethylenediaminetetraacetate solution (50g/L). Dissolve 50g of disodium ethylenediaminetetraacetate in 1000mL of water.

5.3.2.4 Hydrochloric acid-potassium chloride solution (pH 2.5).

16.80 mL of concentrated hydrochloric acid to a 1000 mL volumetric flask, dilute to the mark with water, and mix well;

b) Weigh 14.90g of potassium chloride (KCl) into a 500mL beaker, add an appropriate amount of water to dissolve it, and then transfer it to a 1000mL volumetric flask. Dilute with water to the mark and mix well;

33.5 mL of hydrochloric acid [5.3.2.4a)] and 250 mL of potassium chloride solution [5.3.2.4b)] into a 1000 mL volumetric flask, and dilute with water. Dilute to the mark and mix well.

5.3.2.5 Acetic acid-sodium acetate solution (pH 5.5). Weigh.200g of sodium acetate (or 121g if anhydrous sodium acetate), and place... In a 500mL beaker, dissolve the contents in an appropriate amount of water, then add 9.00mL of glacial acetic acid. Transfer the solution to a 1000mL volumetric flask and dilute to the mark with water. Mix well.

5.3.2.6 Saturated sodium fluoride solution.

5.3.2.7 Thymol blue ethanol solution (1g/L). Weigh 0.1g of thymol blue, dissolve it in 100mL of ethanol (1.4), and mix well.

5.3.2.8 Xylenol orange solution (2g/L). Weigh 0.2g of xylenol orange and dissolve it in 100mL of water.

5.3.2.9 Zinc standard solution. Weigh 2.000g of pure zinc (99.99% or higher), place it in a 300mL beaker, moisten with a small amount of water, and slowly add... Approximately 20 mL of concentrated hydrochloric acid was heated and evaporated until the zinc granules were completely dissolved. After cooling, the pH was adjusted to 5 with ammonia water, and the solution was transferred to a 1000 mL volumetric flask. Dilute with water to the mark and mix well.

5.3.2.10 Concentrated zinc solution. Weigh approximately 4.000g of pure zinc (99.99% or higher), place it in a 300mL beaker, moisten it with a small amount of water, and slowly add the solution. Approximately 20 mL of concentrated hydrochloric acid was heated and evaporated until the zinc granules were completely dissolved. After cooling, the pH was adjusted to 5 with ammonia water, and the solution was transferred to a 1000 mL volumetric flask. Dilute with water to the mark and mix well.

5.3.3.1 Weigh approximately

0.15 g of the sample and place it in a 250 mL beaker. Add 15 mL of hydrochloric acid (1.4), cover with a glass dish, and heat until completely dissolved. Dissolve, rinse the cup and glass with a wash bottle, cool, and then make up to 100 mL in a volumetric flask. Shake well.

5.3.3.2 Transfer 25 mL of the solution to a 300 mL Erlenmeyer flask using a pipette, add 2 drops of thymol blue solution, and neutralize with ammonia (1.4). Once the red color of the solution disappears, add 10 mL of hydrochloric acid-potassium chloride solution and 10 mL of disodium ethylenediaminetetraacetate solution, boil for 2 minutes, and rinse with water. Wash the bottle walls, remove it, and let it cool.

5.3.3.3 Add 10 mL of acetate-sodium acetate solution and 6-8 drops of xylenol orange solution, and titrate with concentrated zinc solution until the solution turns red as the endpoint. (Volume of zinc standard solution not considered).

5.3.3.4 Add 25 mL of saturated sodium fluoride solution, boil for 4 min, remove from heat, cool, add 6 drops of xylenol orange solution, and then use zinc standard solution. The titration endpoint is reached when the solution turns red (consistent with the color of the previous titration). The volume of zinc standard solution consumed at this point is V. Two parallel determinations are performed. The results were obtained from a sample of samples, and the average value was taken.

5.3.4 Calculation of Analysis Results Calculate the mass fraction of aluminum using formula (3).

5.3.5 Precision The difference between analytical results from different laboratories should not exceed the allowable difference listed in Table 2. Table

2 Precision of Experimental Results Aluminum mass fraction /% Tolerance /% 35.00~55.00 0.30

5.3.6 Quality Assurance When abnormal test results occur, a zinc standard solution can be used to replace the sample for analysis. The analytical method can be judged by analyzing the results of the standard solution. The accuracy.

5.4.1 Reagents and Materials

5.4.1.1 Hydrochloric acid (1 4).

0.02 mol/L.

5.4.1.3 Potassium sodium tartrate. 5% aqueous solution.

5.4.1.4 Triethanolamine.

1.1 aqueous solution.

5.4.1.5 Ammonia water. 1 part ammonia solution.

5.4.1.6 Copper reagent.

5.4.1.7 Ammonia-Ammonium Chloride Buffer. Dissolve 54g of ammonium chloride in 350mL of concentrated ammonia solution, then dilute with distilled water to a volume of 1000mL. Inside the bottle.

5.4.1.8 KB Indicator. Grind 1g of Acid Blue K, 2g of Naphthol Green B and 20g of Potassium Chloride into a fine powder and put it into a small wide-mouth bottle.

5.4.2 Analysis Steps Prepare the sample solution according to 5.3.3.1, and transfer 25 mL of the solution to a 300 mL Erlenmeyer flask using a pipette, or directly from the remaining solution in 5.3.3.2. Transfer 25 mL of the sample solution to a 300 mL Erlenmeyer flask. Add 15 mL of 5% potassium sodium tartrate solution and 20 mL of triethanolamine. Solution (1.1), adjusted to pH~10 with

1.1 ammonia solution, added 20 mL of ammonia-ammonium chloride buffer solution,

0.1 g of copper reagent, allowed to stand for 10 min, then added... Add a small amount of KB indicator and titrate with EDTA standard solution (c~0.02mol/L) until the endpoint is reached (blue color).

5.4.3 Calculation of Analysis Results Calculate the mass fraction of magnesium using formula (4).

5.5 Determination of Aluminum-Magnesium Activity

5.5.1 Method Summary The active aluminum and magnesium in the aluminum-magnesium alloy powder sample react with hydrochloric acid to release hydrogen gas. The mass fraction of active aluminum and magnesium is calculated based on the volume of hydrogen gas. Measurement range. Mass fraction of active aluminum magnesium >= 78%.

5.5.2 Reagents

5.5.2.1 Sodium hydroxide solution (200 g/L).

5.5.2.2 Hydrochloric acid (1 4).

5.5.2.3 Blocking solution. 250 g/L sodium chloride solution, using 1 g/L methyl orange solution as an indicator, and adjusting the solution indicator with hydrochloric acid (5.5.2.2). Red and saturated with hydrogen.

5.5.3 Instruments

5.5.3.1 A schematic diagram of the gas measuring instrument is shown in Figure 1. Figure

5.5.3.3 Mercury barometer (accurate to

0.01 kPa).

5.5.4 Analysis Steps

5.5.4.1 Weigh 0.0700g~0.0800g of the sample, accurate to 0.0001g, place the sample in a weighing tube, and transfer it into a pre-filled reaction medium. Place the hydrochloric acid into an Erlenmeyer flask and tighten the rubber stopper.

5.5.4.2 Rotate the gas measuring tube piston to connect the gas measuring tube with the piston's vent. Raise the leveling bottle to expel as much air as possible from the gas measuring tube. Rotate the gas measuring tube piston... Adjust the gas measuring tube stopper to connect the gas measuring tube to the reaction flask, and let it stand for 10 minutes.

5.5.4.3 Adjust the temperature of the cooling water in the water tank to match the temperature of the water in the gas measuring pipe jacket. Check the starting point approximately every 7 minutes. Keeping the reading constant, record the ambient air pressure (P1), temperature (t), and starting point reading.

Note. The optimal measurement temperature is 20°C±2°C.

5.5.4.4 Gently shake the conical flask to allow the sample to react with the sodium hydroxide solution or hydrochloric acid. Place the conical flask in a water trough and repeat approximately every 10 minutes. Shake once. After the reaction is complete, remove the conical flask and let it stand for 10 minutes. Record the endpoint reading approximately every 7 minutes; if the two readings are consistent, record them. The ambient air pressure, temperature, and endpoint readings were measured at this time. Two parallel measurements were performed, and the average value was taken.

Note. Correction is required when the temperature changes.

5.5.5 Calculation of Analysis Results Calculate the mass fraction of active aluminum magnesium according to formula (5).

5.5.6 Permissible Difference The difference between analytical results from different laboratories should not exceed the allowable difference listed in Table 3.

5.5.7 Quality Assurance Before each sample analysis, the gas measuring instrument should be tested for leaks to ensure that there is no gas leakage or entry during the analysis process.

5.6 Determination of Iron Content

5.6.1 Method Summary The sample was dissolved in hydrochloric acid, and ferric iron was reduced with hydroxylamine hydrochloride. The pH of the test solution was controlled at 3.5-4.5.Ferric ions reacted with o-phenanthroline to produce a colorimetric reaction. The absorbance was measured at a wavelength of 510 nm using a spectrophotometer. The measurement range of this method is 0.001% to 3.5%.

5.6.2 Reagents

5.6.2.1 Hydrochloric acid (5 1).

5.6.2.2 Hydrochloric acid (1 1).

5.6.2.3 Sodium hydroxide solution (200 g/L, stored in a plastic bottle).

5.6.2.4 Nickel chloride (NiCl2·6H2O) solution (1g/L).

5.6.2.5 Hydrogen peroxide (

5.6.2.6 Hydroxylamine hydrochloride solution (10 g/L).

5.6.2.7 o-Phenanthroline solution (

2.5 g of o-Phenanthroline (C12H8N2·H2O) or 3 g of o-Phenanthroline hydrochloride. Dissolve (C12H8N2·HCl·H2O) in warm water and cool. Dilute with water to 1000 mL and mix well.

5.6.2.8 Buffer solution. Weigh 272g of sodium acetate (CH3COONa·3H2O), dissolve it in 500mL of water, filter, and then add 240mL of water. Dilute glacial acetic acid (rho=1.05g/mL) with water to 1000mL and mix well.

5.6.2.9 Mixed Solution. Mix hydroxylamine hydrochloride solution, o-phenanthroline solution, and buffer solution in a volume ratio of (1.1.3) and store in brown water. In colored bottles, the storage period shall not exceed 4 weeks.

5.6.2.10 The iron standard storage solution shall be handled in accordance with the following method.

a) Weigh 1.4045 g of ferrous ammonium sulfate [(NH4)2Fe(SO4)2·6H2O] into a 100 mL beaker, add a small amount of water and Add 20 mL of hydrochloric acid (5.6.2.2), and after dissolving, transfer the solution to a 1000 mL volumetric flask. Dilute to the mark with water and mix well. 1 mL of the solution contains

0.2 mg of iron.

b) Weigh 0.2860 g of ferric oxide that has been pre-calcined at 600 °C, place it in a 100 mL beaker, and add 30 mL of hydrochloric acid. (5.6.2.2) Heat until completely dissolved, cool, transfer to a 1000 mL volumetric flask, dilute to the mark with water, and mix well. This solution... 1 mL contains

0.2 mg of iron.

5.6.2.11 Iron Standard Solution. Transfer

50.00 mL of the iron standard stock solution to a 1000 mL volumetric flask, dilute to the mark with water, and mix well. 1 mL of the solution contains

0.01 mg of iron (prepare fresh before use).

5.6.3 Instruments Spectrophotometer.

5.6.4 Analysis Steps

5.6.4.1 Number of measurements Perform two independent measurements and take the average value.

5.6.4.2 Blank Test Perform a blank test along with the sample.

5.6.4.3 Measurement 5.6.4.3.1 Weigh 0.5000g of the sample, accurate to 0.0001g. Place the weighed sample in a 250mL beaker, cover with a watch glass, and divide. Add 15 mL of hydrochloric acid, wait for a vigorous reaction, then slowly heat until completely dissolved. Add 7-8 drops of hydrogen peroxide and heat to remove the fumes. Excess hydrogen peroxide [when the iron mass fraction is less than 0.01%, add 7-8 drops of nickel chloride solution to aid dissolution, continue heating until a paste is formed, then add...] [Dissolve salts by gently heating in 20 mL of water, then cool. If insoluble matter remains, filter using fast-acting metering filter paper and wash with hot water. Filter and wash solution.] Collect in a 250mL beaker. 5.6.4.3.2 The samples with different iron contents were brought to volume according to Table 4. 5.6.4.3.3 Add 25 mL of the mixed solution and dilute to the mark with water, then mix well. Let stand for 30 mi...