Method for determining contents of cyclo-hexogen and aluminum powder in PBX explosive

Abstract

The invention discloses a method for determining the content of cyclo-hexogen and aluminum powder in a PBX explosive, and belongs to the technical field of explosive component measurement. The method comprises the following steps: dividing m to-be-tested PBX explosive samples into m1 calibration set samples and m2 verification set samples; collecting near infrared data of all samples; preprocessing all collected near-infrared data, and then screening variables in a full spectrum by adopting a joint interval partial least square method; establishing a correction model by adopting a cross test method, and selecting an optimal model variable according to a minimum value of a root-mean-square error of data cross validation of the samples in the correction set to obtain a hexogen recommendation model and an aluminum powder recommendation model; respectively predicting the content of the hexogen and the content of the aluminum powder in the verification set sample according to the hexogen recommendation model and the aluminum powder recommendation model, and selecting an optimal model according to the minimum value of the root-mean-square error predicted by the verification set. The method is suitable for determining the contents of cyclo-hexogen and aluminum powder in the PBX explosive, and is convenient to operate and rapid and accurate in analysis.

Description

Technical Field

[0001] This invention relates to the field of explosives composition technology, and more specifically, to a method for determining the content of RDX and aluminum powder in PBX explosives. Background Technology

[0002] PBX explosives endow blended explosives with superior overall performance, such as higher energy density, excellent mechanical properties, and higher safety performance. PBX explosives generally contain RDX, aluminum powder, and binders; the detection of their component content is an essential testing item for explosive production and quality assurance.

[0003] The content of RDX and aluminum powder in PBX explosives is usually determined by liquid chromatography and chemical titration, respectively. These methods are cumbersome, time-consuming and labor-intensive, and the use of large amounts of organic solvents poses safety hazards and environmental pollution problems.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for determining the content of RDX and aluminum powder in PBX explosives, so as to solve or improve the above-mentioned technical problems.

[0006] This invention can be implemented as follows: In a first aspect, the present invention provides a method for determining the content of RDX and aluminum powder in PBX explosives, comprising the following steps: The m PBX explosive samples to be tested are divided into m1 calibration set samples and m2 validation set samples, m1+m2=m, m1>m2; the components of the PBX explosive samples to be tested include RDX, aluminum powder and binder; Near-infrared data were collected for all PBX explosive samples; All the acquired near-infrared data were preprocessed, and then the variables in the full spectrum were screened using the joint interval partial least squares method. A calibration model was established using cross-validation. The optimal model variables were selected based on the minimum root mean square error of the cross-validation data of the calibration set samples, resulting in the RDX recommended model and the aluminum powder recommended model. The contents of RDX and aluminum powder in the validation set samples are predicted using the RDX recommendation model and the aluminum powder recommendation model, respectively. The optimal model is selected based on the minimum root mean square error of the validation set prediction.

[0007] In an optional embodiment, the PBX explosive sample contains 54% to 71.3% RDX and 20.7% to 37.5% aluminum powder.

[0008] In an optional implementation, m1:m2 is 6:4 to 8:2.

[0009] In an optional implementation, m1:m2 is 7:3.

[0010] In an optional implementation, the near-infrared spectral data are obtained using infrared diffuse reflectance scanning and in quartz sample cup-rotation mode.

[0011] In an optional implementation, the near-infrared data acquisition range is 10000 cm. -1 ~4000cm -1 The number of scans ranges from 16 to 64, with a near-infrared resolution of 4 cm. -1 ~16cm -1 .

[0012] In an optional implementation, the near-infrared data acquisition range is 10000 cm. -1 ~4000cm -1 The number of scans was 32, and the near-infrared resolution was 8cm. -1 .

[0013] In optional implementations, the preprocessing methods for near-infrared data include at least one of the following: first derivative, second derivative, standard variable transformation, and multivariate scattering correction.

[0014] In an optional implementation, the Hexogene recommended model by selecting 4300cm. -1 ~4600cm -1 5200cm -1 ~5500cm -1 5800cm -1 ~6100cm -1 and 7300cm -1 ~7600cm -1 The spectral data within the band was modeled.

[0015] In an optional implementation, the aluminum powder recommended model is determined by selecting 4300 cm⁻¹. -1 ~4900cm -1 5200cm -1 ~5500cm -1 and 5500cm -1 ~5800cm -1 The spectral data within the band was modeled.

[0016] The beneficial effects of this invention include: This invention provides a method for determining the content of RDX and aluminum powder in PBX explosives. The method is simple, easy to operate, and allows for rapid and convenient data processing, significantly saving experimental time and chemical reagents. Furthermore, the method avoids the use of solvents, reducing pollution and achieving a simple, rapid, and accurate determination of the RDX and aluminum powder content in PBX explosives. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The curve showing the relationship between the actual and predicted values ​​of rhein content in the experimental example; Figure 2 The curve shows the relationship between the actual and predicted values ​​of aluminum powder content in the experimental example. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0020] The method for determining the content of RDX and aluminum powder in PBX explosives provided by the present invention will be described in detail below.

[0021] This invention provides a method for determining the content of RDX and aluminum powder in PBX explosives, comprising the following steps: The m PBX explosive samples to be tested are divided into m1 calibration set samples and m2 validation set samples, m1+m2=m, m1>m2; the components of the PBX explosive samples to be tested include RDX, aluminum powder and binder; Near-infrared data were collected for all PBX explosive samples; All the acquired near-infrared data were preprocessed, and then the variables in the full spectrum were screened using the joint interval partial least squares method. A calibration model was established using cross-validation. The optimal model variables were selected based on the minimum root mean square error of the cross-validation data of the calibration set samples, resulting in the RDX recommended model and the aluminum powder recommended model. The contents of RDX and aluminum powder in the validation set samples are predicted using the RDX recommendation model and the aluminum powder recommendation model, respectively. The optimal model is selected based on the minimum root mean square error of the validation set prediction.

[0022] In this invention, the PBX explosive sample contains 54% to 71.3% RDX and 20.7% to 37.5% aluminum powder.

[0023] The method provided by this invention is applicable to testing PBX explosives containing the above-mentioned amounts of RDX and aluminum powder in addition to the binder, in order to obtain accurate test results.

[0024] In this invention, the calibration set is used to establish a calibration model, and the validation set is used to test the accuracy of the model. In some optional embodiments, m1:m2 can be 6:4 to 8:2, such as 6:4, 7:3, or 8:2. In some preferred embodiments, m1:m2 is 7:3. By dividing the PBX explosive samples to be tested into calibration set samples and validation set samples according to the above ratio, it is beneficial to improve the accuracy of modeling and obtain more accurate measurement results.

[0025] In this invention, near-infrared spectral data are obtained using infrared diffuse reflectance scanning and in quartz sample cup-rotation mode. This method helps ensure uniform exposure of the sample during spectral acquisition, avoids spectral deviations caused by local component differences, and improves the representativeness of the detection.

[0026] In some optional implementations, the near-infrared data acquisition range is 10000 cm. -1 ~4000cm -1 The number of scans can be 16 to 64 (e.g., 16, 24, 32, 40, 48, 56, or 64), with a near-infrared resolution of 4 cm. -1 ~16cm -1 (e.g., 4cm) -1 8cm -1 12cm -1 Or 16cm -1 wait).

[0027] In some preferred embodiments, the near-infrared data acquisition range is 10000 cm. -1 ~4000cm -1 The number of scans was 32, and the near-infrared resolution was 8cm. -1 .

[0028] It should be noted that aluminum powder has virtually no absorption in the near-infrared spectral region, but it can cause significant noise, affecting the spectral identification of other components in PBX explosives. Therefore, when using near-infrared spectroscopy to determine the content of RDX and aluminum powder in PBX explosives, it is necessary to select appropriate spectral preprocessing methods and effective spectral ranges, extract effective information, eliminate interfering information, and establish a small analytical error to avoid affecting the measurement results.

[0029] In some alternative implementations, the preprocessing of near-infrared data may include at least one of first derivative, second derivative, standard variable transformation (SNV), and multivariate scattering correction (MSC).

[0030] In some alternative implementations, the Hexogene recommended model by selecting 4300cm -1 ~4600cm -1 5200cm -1 ~5500cm -1 5800cm -1 ~6100cm -1 and 7300cm -1 ~7600cm -1 The spectral data within the band was modeled.

[0031] In some alternative implementations, the aluminum powder recommended model is achieved by selecting 4300 cm⁻¹. -1 ~4900cm -1 5200cm -1 ~5500cm -1 and 5500cm -1 ~5800cm -1 The spectral data within the band was modeled.

[0032] As described above, the method provided by this invention is simple, easy to operate, and provides rapid and convenient data processing, significantly saving experimental time and chemical reagents. The determination process avoids the use of solvents, reducing pollution and achieving a simple, rapid, and accurate determination of the RDX and aluminum powder content in PBX explosives.

[0033] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0034] Example 1 This embodiment provides a method for determining the content of RDX and aluminum powder in PBX explosives, including the following steps: (1) Preparation of PBX explosive samples.

[0035] Eighty PBX explosive samples were prepared. The RDX content in these samples ranged from 54% to 71.3%, and the aluminum powder content ranged from 20.7% to 37.5%. The RDX, aluminum powder, and binder were uniformly mixed in each PBX explosive sample.

[0036] The Kennard-Stone method was used to divide 80 PBX explosive samples into calibration and validation sets at a ratio of 7:3, resulting in 56 calibration set samples and 24 validation set samples.

[0037] (2) Collect near-infrared spectral data of each PBX explosive sample prepared.

[0038] The near-infrared spectroscopy acquisition method was diffuse reflectance scanning, with the quartz sample cup-rotation mode selected. The near-infrared spectroscopy acquisition range was 10000 cm⁻¹. -1 ~4000cm -1 The number of scans was 32, and the near-infrared resolution was 8cm. -1 .

[0039] (3) Establish a calibration model.

[0040] The spectrum was preprocessed using the first derivative, and the variables in the full spectrum were screened using the joint interval partial least squares method. A calibration model was established using the cross-validation method, and the optimal model variables were selected based on the minimum root mean square error of the calibration set cross-validation. The recommended models for Rhesin and aluminum powder were obtained respectively. Specifically, the determination of the recommended model for RDX includes: dividing the full spectrum of PBX explosive into 20 sub-intervals, calculating the model for 4 joint intervals, calculating the root mean square value of cross-validation error (RMSECV) using leave-one-out cross-validation, and establishing and predicting the model using the preferred interval. The final selected interval is [2,5,7,12] (4300 cm⁻¹). -1 ~4600cm -1 5200cm -1 ~5500cm -1 5800cm -1 ~6100cm -1 and 7300cm -1 ~7600cm -1 Modeling spectral data for (band) results in the minimum RMSECV, as shown in Table 1.

[0041] Table 1. Model RMSECV values ​​of RDX content in PBX explosives for different interval selections.

[0042] The determination of the aluminum powder recommended model includes: dividing the full spectrum of the selected PBX explosive into 20 sub-intervals, calculating the model for 3 joint intervals, calculating the root mean square value of cross-validation error (RMSECV) using leave-one-out cross-validation, and establishing and predicting the model using the preferred interval. The final selected interval is [2,5,6] (4300cm). -1 ~4900cm -1 5200cm -1 ~5500cm -1 and 5500cm -1 ~5800cm -1 Spectral data within the band are modeled, at which point RMSECV is minimized, as shown in Table 2.

[0043] Table 2. RMSECV values ​​of aluminum powder content in PBX explosives under different range selections

[0044] (4) Selection and verification of the optimal model Based on the aforementioned RDX and aluminum powder recommendation models, the contents of RDX and aluminum powder in the validation set samples are predicted respectively. The optimal model is selected based on the minimum root mean square error of the validation set prediction.

[0045] The final determined optimal model for Hexos is: R 2 cal (Correlation coefficient for the calibration set, the same below) = 0.9905, RMSEC (Root mean square value of the correction set error, the same below) = 0.4681, R 2 test (Validation set determination coefficient, the same below) = 0.9734, RMSEP (Root mean square error of validation set, the same below) = 0.6240; the final optimal model for aluminum powder is: R 2 cal =0.9913, RMSEC =0.4361, R 2 test =0.9836, RMSEP =0.4921; indicating that the model has good correlation.

[0046] Example 2 The difference between this embodiment and Embodiment 1 is that: Eighty PBX explosive samples were divided into 48 calibration set samples and 32 validation set samples. Near-infrared data acquisition range was 10000 cm⁻¹. -1 ~4000cm -1The number of scans was 16, and the near-infrared resolution was 4cm. -1 .

[0047] Example 3 The difference between this embodiment and Embodiment 1 is that: Eighty PBX explosive samples were divided into 64 calibration set samples and 16 validation set samples. Near-infrared data acquisition range was 10000 cm⁻¹. -1 ~4000cm -1 The number of scans was 64, and the near-infrared resolution was 16cm. -1 .

[0048] Test case The results of RDX and aluminum powder content determined according to Example 1 above were compared with those of PBX explosive samples determined by liquid chromatography and chemical titration methods in the prior art to demonstrate the accuracy of the determination method of the present invention. The results are shown in Table 3 and below. Figure 1 and Figure 2 As shown.

[0049] The method for determining the rhein content in PBX explosive samples by liquid chromatography includes: accurately weighing 0.1 g (accurate to 0.0001 g) of PBX explosive into a 100 mL volumetric flask, adding 60 mL of acetone, soaking and dissolving for about 12 h, then dissolving by sonication for 1 min, continuing to soak for 48 h, adding acetone to make up to volume, mixing well, filtering with a 0.22 μm organic system filter membrane, and using the filtrate as the sample solution. The determination is performed under the following chromatographic conditions: Dikma C18 column (5 μm, 4.6 mm × 150 mm), mobile phase of methanol-water-acetonitrile (volume ratio of 22:64:14), column temperature of 35 ℃, flow rate of 0.7 mL / min, injection volume of 10 μL, detection wavelength of 220 nm, and quantification using the external standard method.

[0050] The method for determining the aluminum powder content in PBX explosive samples by chemical titration includes: Weighing 0.15 g of PBX explosive into a 300 mL Erlenmeyer flask, adding a small amount of water to moisten it, adding 10 mL of nitric acid, shaking well, and then adding 5 mL of perchloric acid, shaking well again. The Erlenmeyer flask is placed on a continuously adjustable electric heater with an asbestos mesh and the temperature is gradually increased until the sample is completely dissolved and white perchloric acid fumes are emitted. It is then removed and cooled to room temperature. 50 mL of water, 50.00 mL of 0.05 mol / L disodium ethylenediaminetetraacetate standard solution, and two drops of dimethyl yellow indicator solution are added. The solution is adjusted with ammonia water until it changes from red to light yellow, and the pH value is approximately 3.5. The solution is boiled for 3 minutes, cooled to room temperature under running water, and 10 mL of hexamethylenetetramine solution is added to adjust the pH value to 5-6. The solution is then shaken well. Add two to three drops of xylenol orange indicator to the above solution, and titrate with zinc salt standard titration solution until the solution changes from yellow to red as the endpoint. Record the volume of zinc salt standard titration solution consumed.

[0051] The aluminum powder content is calculated as follows: W(Al) = [(c1v1-c2v2)×26.98 / (m×1000)]×100.

[0052] Wherein, c1 is the molar concentration of the disodium ethylenediaminetetraacetate standard titration solution, in mol / L; v1 is the volume of disodium ethylenediaminetetraacetate standard titration solution added, in mL; c2 is the molar concentration of the zinc salt standard titration solution, in mol / L; v2 is the volume of zinc salt standard titration solution consumed in the titration, in mL; 26.98 is the molar mass of aluminum, in g / mol; and m is the mass of the sample, in g.

[0053] Error = [(predicted value - actual value) / actual value] × 100%, with the value rounded to two decimal places.

[0054] Table 3. Actual and predicted values ​​of RDX and aluminum powder content in the validation set samples.

[0055] In Table 3, for the same sample, the true value of RDX is the result obtained by liquid chromatography, and the predicted value of RDX is the result obtained by the method of Example 1; the true value of aluminum powder is the result obtained by chemical titration, and the predicted value of aluminum powder is the result obtained by the method of Example 1. The error is the difference between the true value and the predicted value.

[0056] As can be seen from Table 3, the results obtained by the method provided by the present invention are basically consistent with the true values, indicating that the method provided by the present invention can accurately determine the content of RDX and aluminum powder in PBX explosives.

[0057] Similarly, comparing the results obtained by the methods provided in Examples 2-3 with the true values ​​obtained by liquid chromatography and chemical titration, it is shown that the test results of RDX and aluminum powder are basically consistent, and the error corresponding to Example 1 is smaller than the error corresponding to Example 2 and Example 3.

[0058] Comparative Example 1 This comparative example provides an explosive containing 50% RDX and 40% aluminum powder, with the balance being a binder.

[0059] The test was conducted according to the test method provided in Example 1. The results showed that the measured values ​​of RDX and aluminum powder were significantly different from the true values ​​of RDX and aluminum powder obtained by liquid chromatography and chemical titration.

[0060] Comparative Example 2 This comparative example provides an explosive containing 80% RDX and 10% aluminum powder, with the balance being a binder.

[0061] The test was conducted according to the test method provided in Example 1. The results showed that the measured values ​​of RDX and aluminum powder were significantly different from the true values ​​of RDX and aluminum powder obtained by liquid chromatography and chemical titration.

[0062] Based on the results of Comparative Examples 1 and 2, it is demonstrated that the method provided by this invention is only applicable to PBX explosives with a RDX content of 54% to 71.3% and an aluminum powder content of 20.7% to 37.5%.

[0063] In summary, this invention provides a method for determining the content of RDX and aluminum powder in PBX explosives. This method is simple, easy to operate, and allows for rapid and convenient data processing, significantly saving experimental time and chemical reagents. Furthermore, the method avoids the use of solvents, reducing pollution and achieving a simple, rapid, and accurate determination of the RDX and aluminum powder content in PBX explosives.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining the content of RDX and aluminum powder in PBX explosives, characterized in that, Includes the following steps: The m PBX explosive samples to be tested are divided into m1 calibration set samples and m2 validation set samples, where m1 + m2 = m and m1 > m2; the components of the PBX explosive samples to be tested include RDX, aluminum powder and binder. Near-infrared data were collected for all PBX explosive samples; All the acquired near-infrared data were preprocessed, and then the variables in the full spectrum were screened using the joint interval partial least squares method. A calibration model was established using cross-validation. The optimal model variables were selected based on the minimum root mean square error of the cross-validation data of the calibration set samples, resulting in the RDX recommended model and the aluminum powder recommended model. The RDX and aluminum powder content in the validation set samples are predicted based on the RDX recommendation model and aluminum powder recommendation model, respectively. The optimal model is selected based on the minimum root mean square error of the validation set prediction.

2. The method according to claim 1, characterized in that, The PBX explosive sample contained 54% to 71.3% RDX and 20.7% to 37.5% aluminum powder.

3. The method according to claim 1, characterized in that, The ratio of m1:m2 is 6:4 to 8:

2.

4. The method according to claim 3, characterized in that, The ratio of m1 to m2 is 7:

3.

5. The method according to claim 1, characterized in that, Near-infrared spectral data were obtained using infrared diffuse reflectance scanning and in quartz sample cup-rotation mode.

6. The method according to claim 1, characterized in that, Near-infrared data acquisition range is 10000cm -1 ~4000cm -1 The number of scans ranges from 16 to 64, with a near-infrared resolution of 4 cm. -1 ~16cm -1 .

7. The method according to claim 6, characterized in that, Near-infrared data acquisition range is 10000cm -1 ~4000cm -1 The number of scans was 32, and the near-infrared resolution was 8cm. -1 .

8. The method according to claim 1, characterized in that, Preprocessing methods for near-infrared data include at least one of the following: first derivative, second derivative, standard variable transformation, and multivariate scattering correction.

9. The method according to claim 1, characterized in that, The Hexogen recommended model selects 4300cm. -1 ~4600cm -1 5200cm -1 ~5500cm -1 5800cm -1 ~6100cm -1 and 7300cm -1 ~7600cm -1 The spectral data within the band was modeled.

10. The method according to claim 1, characterized in that, The recommended aluminum powder model selects 4300cm -1 ~4900cm -1 5200cm -1 ~5500cm -1 and 5500cm -1 ~5800cm -1 The spectral data within the band was modeled.

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