A method for determining the concentration of hydroxylamine nitrate

Abstract

The application discloses a method for determining the concentration of hydroxylamine nitrate, preparing verification set and correction set samples in the concentration range of spent fuel reprocessing process, collecting near-infrared absorption spectra of the verification set and the correction set, establishing a quantitative correction model and verifying to obtain a quantitative model, performing near-infrared spectrum detection on a solution of the spent fuel reprocessing process, not needing to pretreat the solution, and simultaneously obtaining the concentration of hydroxylamine nitrate by processing the absorption spectra of the corresponding wavelengths by the quantitative model; the method is simple, improves the analysis efficiency, and is high in accuracy; and the method provides effective data support for online detection of the concentration of hydroxylamine nitrate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of analytical chemistry, and particularly relates to a method for determining the concentration of hydroxylamine nitrate. BACKGROUND

[0002] The spent fuel reprocessing of a nuclear power reactor generally adopts a PUREX (Plutonium Uranium Redox Extraction) process, which mainly utilizes the high extractability of hydroxylamine nitrate to uranium and plutonium and the easy oxidation-reduction property of plutonium to realize the extraction and separation of uranium and plutonium. In the plutonium purification cycle, the hydroxylamine nitrate-hydrazine nitrate-nitric acid solution is used as a reducing agent and a stripping agent to realize the separation and purification of plutonium, and the content of the solution directly affects the reduction and stripping efficiency of plutonium and ultimately determines the yield of plutonium. Therefore, the concentration of the related components in the solution needs to be accurately measured.

[0003] The detection methods of hydroxylamine nitrate generally include acid-base titration, oxidation-reduction titration, diazo coupling colorimetric spectrophotometry, high performance liquid chromatography, and automatic potentiometric titration. These detection methods have complicated operation steps, high requirements for manual operation, and are difficult to realize direct online analysis. SUMMARY

[0004] In view of the above technical problems existing in the prior art, the purpose of the present application is to provide a method for online, rapid and accurate detection of the concentration of hydroxylamine nitrate in the spent fuel reprocessing process.

[0005] To achieve the above-mentioned purpose of the application, the technical scheme adopted by the present application is as follows: a method for determining the concentration of hydroxylamine nitrate, comprising the following steps:

[0006] (1) According to the concentration range of hydroxylamine nitrate in the spent fuel reprocessing process, calibration set and verification set samples within the concentration range are prepared;

[0007] (2) With air as a reference, near-infrared spectrum detection is performed on the calibration set and verification set samples, respectively, and the absorption spectrum of the samples is collected;

[0008] (3) A quantitative calibration model is established according to the collected absorption spectrum of the calibration set samples, and the absorption spectrum of the verification set samples is verified by the quantitative calibration model to obtain a quantitative model;

[0009] (4) Near-infrared spectrum detection is performed on the solution of the spent fuel reprocessing process, and the absorption spectrum of the corresponding wavelength is processed by the quantitative model to obtain the concentration of hydroxylamine nitrate in the solution.

[0010] The beneficial effects brought by the technical scheme of the present application are that the method for determining the concentration of hydroxylamine nitrate establishes a quantitative correction model according to the near-infrared absorption spectrum of the collected calibration set sample, corrects the quantitative correction model to obtain a quantitative model by using the near-infrared absorption spectrum of the validation set sample, detects the near-infrared spectrum of the spent fuel reprocessing process solution, does not need to pretreat the solution, inputs the absorption spectrum of the corresponding wavelength into the quantitative model for processing to obtain the concentration of hydroxylamine nitrate in the spent fuel reprocessing process solution, the method improves the analysis efficiency, has high accuracy, does not need manual quantitative operation, and provides effective data support for online detection of the concentration of hydroxylamine nitrate. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is a method flowchart for determining the concentration of hydroxylamine nitrate according to the present application;

[0012] Figure 2 is a near-infrared spectrum diagram of four different concentrations of hydroxylamine nitrate solution according to the present application;

[0013] Figure 3 is a quantitative model for determining the concentration of hydroxylamine nitrate according to the method of the present application. DETAILED DESCRIPTION

[0014] The present application will be described in detail below in combination with the drawings and examples.

[0015] Referring to the drawings Figure 1 The present application provides a method for determining the concentration of hydroxylamine nitrate, which comprises the following steps:

[0016] (1) According to the concentration range of hydroxylamine nitrate in the spent fuel reprocessing process, calibration set and validation set samples in the concentration range are prepared;

[0017] (2) The calibration set and validation set samples are respectively detected by near-infrared spectrum detection with air as a reference, and the absorption spectrum of the sample is collected;

[0018] (3) A quantitative correction model is established according to the collected absorption spectrum of the calibration set sample, and the absorption spectrum of the collected validation set sample is verified by the quantitative correction model to obtain a quantitative model;

[0019] (4) The spectrum of the spent fuel reprocessing process solution is detected, the absorption spectrum of the corresponding wavelength is collected, and the concentration of hydroxylamine nitrate in the solution is obtained by processing the absorption spectrum through the quantitative model.

[0020] Preferably, in the step (1), 31 different concentration samples are prepared, wherein 26 samples of the calibration set have a hydroxylamine nitrate concentration ranging from 0.1 to 0.99 mol / L, and 5 samples of the validation set have the same concentration range as the calibration set but different specific concentrations from the calibration set samples.

[0021] Preferably, in the step (2), the instrument resolution is set to 4 cm -1 with air as the reference, 32 accumulations, and a 1 mm quartz cuvette as the measuring cell, and the absorption spectrum of the above samples is collected.

[0022] Referring to the accompanying drawings Figure 2 , the spectrum shows a clear change trend between 4250 and 4840 cm -1 , which contains the first-order frequency doubling and frequency combination of the chemical bond stretching vibration of the hydrogen-containing group, indicating that the near-infrared spectrum can be used to detect the concentration of hydroxylamine nitrate.

[0023] Preferably, in the step (3), a quantitative calibration model for determining the concentration of hydroxylamine nitrate is established according to the absorption spectrum of the above calibration set samples combined with the partial least squares (PLS).

[0024] The parameters for establishing the quantitative calibration model are shown in Table 1. The root mean square error of cross-validation (RMSECV) of the calibration model for hydroxylamine nitrate is 0.0016, the determination coefficient R 2 is 99.89, and the detection range is 0.1-1 mol / L.

[0025] Table 1: Parameters of the quantitative calibration model

[0026]

[0027] Referring to the accompanying drawings Figure 3 , the prediction results of the quantitative model of the embodiment of the present application for hydroxylamine nitrate in the sample have good correlation with the reference values.

[0028] Preferably, in the step (4), the concentration of hydroxylamine nitrate in the spent fuel reprocessing process solution is determined by using the above established quantitative model, and the results are shown in Table 2.

[0029] Table 2: Measurement results of samples

[0030]

[0031] As can be seen from Table 2, the relative deviation of the prediction of hydroxylamine nitrate by the quantitative model of the embodiment of the present application is less than 2.5%. The prediction results of the model have no significant difference from the actual values, indicating that the quantitative model of the embodiment of the present application has high accuracy and can be used for quantitative detection of the content of hydroxylamine nitrate in actual processes.

[0032] It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

Claims

1. A method for determining the concentration of hydroxylamine nitrate, characterized in that: Includes the following steps: (1) Based on the concentration range of hydroxylamine nitrate in the spent fuel reprocessing process, prepare calibration and validation set samples within the concentration range; (2) Using air as a reference, near-infrared spectroscopy was performed on the calibration set and validation set samples respectively, and the absorption spectra of the samples were collected. The wavelength range of the near-infrared spectroscopy was 4424-4600 cm⁻¹. -1 ; (3) Establish a quantitative calibration model based on the absorption spectra of the collected calibration set samples, and verify the quantitative calibration model using the absorption spectra of the collected validation set samples to obtain the quantitative model; (4) Perform spectral detection on the spent fuel reprocessing process solution, and process the collected absorption spectra at the corresponding wavelengths using the quantitative model to obtain the concentration of hydroxylamine nitrate in the solution.

2. The method for determining the concentration of hydroxylamine nitrate according to claim 1, characterized in that: In step (1), the concentrations of the calibration set and the validation set samples are different.

3. The method for determining the concentration of hydroxylamine nitrate according to claim 1, characterized in that: In step (2), air is used as a reference, and the instrument resolution is set to 4cm. -1 A 1mm quartz cuvette was used as the measurement cell to collect the absorption spectra of the calibration set and validation set samples.

4. The method for determining the concentration of hydroxylamine nitrate according to claim 1, characterized in that: In step (3), a quantitative correction model for the determination of hydroxylamine nitrate concentration is established based on the absorption spectrum of the above-mentioned calibration set samples combined with partial least squares method.

Images