Uranium ore grade separation method based on γ radiation field numerical matrix decomposition

Abstract

The invention discloses a uranium ore grade sorting method based on the decomposition of a gamma radiation field numerical matrix. In the process of ore transportation, the method uses an array detection system to measure the gamma counting rate of the ore; the gamma counting rate of the ore of each detector is deducted from the background to obtain a net counting rate, and the counting rate curves are respectively constructed; a gamma radiation field intensity distribution numerical matrix is ​​established according to the counting rate curve; the gamma radiation field intensity distribution numerical matrix is ​​decomposed to obtain a decomposition coefficient, and an equation group with the central field intensity of the gamma radiation field as an unknown variable is constructed according to the decomposition coefficient, and the central field intensity of each gamma radiation field is obtained by solving; the central field intensity of the gamma radiation field is compared with a standard source to calculate the uranium content of each ore, and the standard source is the central field intensity of the gamma radiation field of an ore with a known uranium content, and the uranium ore grade is divided and classified according to the uranium content. The invention uses an array detection system to measure and decompose the gamma radiation field, and can realize real-time detection of the uranium ore content and classification.

Description

Technical Field

[0001] The invention belongs to the technical field of rapid separation of uranium ore elements, and in particular relates to a uranium ore grade separation method based on gamma radiation field numerical matrix decomposition. Background Art

[0002] Uranium ore resources are characterized by uneven mineralization, with medium and low-grade ores accounting for the majority and high waste rock content. The increase in the depletion rate of mined ore and the decrease in the grade of the original ore are the main problems faced by uranium mining. The use of pre-sorting technology to treat the original ore can simplify the subsequent hydrometallurgical process to achieve the purpose of reducing costs and making full use of resources. Ore sorting technology uses the differences in physical characteristics such as optical properties, electrical properties, magnetic properties, radioactivity, and radiation characteristics between ore and waste rock in the original ore to achieve separation. Most of the existing uranium ore sorting methods are radioactive sorting, but traditional radioactive sorting methods are all for single block uranium ore, and by improving the system's radiation shielding ability and increasing the spacing between the ores to be sorted to avoid the mutual influence between different ores when measuring the gamma ray intensity. This method has the disadvantages of complex operation, slow sorting speed and small processing capacity. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a uranium ore grade sorting method based on γ radiation field numerical matrix decomposition. The method adopts an array γ radiation detector to quickly measure the counting rate generated by the uranium ore at different positions when the uranium ore passes through the detection area, so as to solve the problem that the counting rate change of the ore sample has a great influence on the prediction accuracy of the grade classification, realize the decomposition of the γ radiation field generated by multiple ore samples, and can quickly and effectively quantify and classify the uranium ore samples, overcome the influence of the simultaneous measurement of multiple ore samples on the classification, and improve the classification speed.

[0004] The present invention is realized by the following technical scheme: a uranium ore grade separation method based on γ radiation field numerical matrix decomposition comprises the following steps:

[0005] Step S1: During the ore transportation process, the gamma count rate of the ore is measured by using the array detection system;

[0006] Step S2: subtract the background from the ore gamma counting rate of each detector to obtain the net counting rate, and construct the counting rate curves respectively;

[0007] Step S3: establishing a numerical matrix of the γ radiation field intensity distribution according to the count rate curve;

[0008] Step S4: Decomposing the numerical matrix of the γ radiation field intensity distribution to obtain decomposition coefficients, constructing an equation group with the γ radiation field center intensity as an unknown variable according to the decomposition coefficients, and solving to obtain the center intensity of each γ radiation field;

[0009] Step S5: Calculate the uranium content of each ore by comparing the center field intensity of the gamma radiation field with a standard source, where the standard source is the center field intensity of the gamma radiation field of an ore with a known uranium content, and classify the uranium ore grade according to the uranium content.

[0010] Further preferably, the array detection system consists of a plurality of detectors arranged in an array, a digital pulse multi-channel spectrum analyzer and a high voltage supply module.

[0011] Further preferably, in step S1, the ore gamma count rate refers to the count rate in a characteristic spectrum of gamma rays of the uranium ore.

[0012] Further preferably, the array detection system adopts an energy spectrum counting rate in the energy range of [0.4MeV, 2.5MeV].

[0013] Further preferably, in step S2, is the distance coordinate of the jth measuring point, j is the measuring point number; represents the net count rate of the characteristic spectrum of the i-th detector at the j-th measurement point, , K is the total number of measurement points, When the ore moves to the The net count rate of the characteristic spectrum of each measuring point of the i-th detector is connected in sequence, and the net count rate of the characteristic spectrum of each measuring point of the i-th detector is obtained. The counting curve of each detector is .

[0014] In step S3, all count rate curves are sorted according to the order of the detectors and combined to obtain a numerical matrix of the gamma radiation field intensity distribution.

[0015] In step S4, the decomposition coefficient is obtained according to equation (1):

[0016] ;

[0017] in, represents the decomposition coefficient of the characteristic spectrum of the jth measuring point of the i-th detector, It represents the counting rate when the ore moves to the top of the i-th detector.

[0018] In step S4, the equation group with the center field intensity of the gamma radiation field as an unknown variable is:

[0019] ;

[0020] in, is the central field strength of the γ radiation field of ore a, is the central field strength of the γ radiation field of ore b, represents the net count rate of the characteristic spectrum of the i-th detector at the j+1-th measurement point, It represents the net count rate of the characteristic spectrum of the i-th detector at the j+2-th measurement point, represents the decomposition coefficient of the characteristic spectrum of the j+1th measuring point of the i-th detector, Represents the decomposition coefficient of the characteristic spectrum of the j+2th measurement point of the i-th detector.

[0021] The present invention obtains the γ radiation field intensity distribution data of the uranium ore and uses the corresponding decomposition algorithm to calculate the central field intensity of the γ radiation field of a single ore and compares it with the counting rate of the uranium ore with standard content, thereby realizing online detection and classification of the uranium content of the ore.

[0022] Compared with the radioactive sorting method for a single piece of uranium ore, the present invention decomposes the gamma radiation field intensity of multiple radioactive sources. There is no need to arrange uranium ores at a certain distance and add radiation shielding devices. It can also greatly improve the sorting speed, thereby having the advantages of increasing ore processing capacity and reducing equipment costs. It can also realize real-time classification of uranium ore content through computer programming. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 is a flow chart of the method of Example 1;

[0025] Figure 2 It is the count rate curve diagram of Example 1;

[0026] Figure 3 It is the decomposition coefficient distribution diagram of Example 1;

[0027] Figure 4 This is the field intensity distribution diagram of the dual-source gamma radiation field of Example 1;

[0028] Figure 5 is a gamma radiation field intensity distribution diagram of the decomposed radioactive source 1 of Example 1;

[0029] Figure 6 This is the γ radiation field intensity distribution diagram of the decomposed radioactive source 2 in Example 1. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0031] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0032] Example 1

[0033] According to the radioactive characteristics, uranium series elements are divided into uranium group and radium group radioactive elements. 238 U to 230 Th is a uranium group nuclide, and the gamma rays it emits are concentrated in the low energy region and have a very low emission probability. The gamma rays produced by radium group nuclides mainly come from 214 Pb and 214 The gamma rays of Bi and radium are concentrated in the middle and high energy regions and have a large emission probability. They are the main research objects of gamma spectrum measurement. The main decay products of uranium and their gamma ray energies are shown in Table 1.

[0034] Table 1 Uranium series decay products and gamma ray energy

[0035]

[0036] The energy peaks and Compton plateau count rates of the medium and low energy rays measured by the array detection system are very large, and the energy peaks and Compton plateaus of high energy and low energy differ by 2 orders of magnitude on the energy spectrum. The gamma counts in the low energy zone will seriously interfere with the ore quantification, so the low energy zone count rate does not participate in the uranium ore quantification. Under the premise of ensuring a high total count rate, the lower limit of the energy zone for rapid quantification of uranium ore with the gamma energy spectrum is 0.4MeV, and the maximum energy of the main characteristic peaks of the uranium series is 2.446 MeV. In this embodiment, the array detection system also uses an energy spectrum count rate with an energy range of [0.4MeV, 2.5MeV] for uranium ore quantification, and the consistency of each detector in the system is good.

[0037] The array detection system consists of multiple detectors arranged in an array, a digital pulse multi-channel spectrum analyzer and a high-voltage supply module.

[0038] like Figure 1 As shown, the uranium ore grade separation method based on the γ radiation field numerical matrix decomposition of this embodiment includes the following steps:

[0039] Step S1: During the ore transportation process, the gamma count rate of the ore is measured by using an array detection system; the detector of the array detection system is a sodium iodide detector;

[0040] Step S2: subtract the background from the ore gamma counting rate of each detector to obtain the net counting rate, and construct the counting rate curves respectively;

[0041] Step S3: establishing a numerical matrix of the γ radiation field intensity distribution according to the count rate curve;

[0042] Step S4: Decomposing the numerical matrix of the γ radiation field intensity distribution to obtain decomposition coefficients, constructing an equation group with the γ radiation field center intensity as an unknown variable according to the decomposition coefficients, and solving to obtain the center intensity of each γ radiation field;

[0043] Step S5: Calculate the uranium content of each ore by comparing the center field intensity of the gamma radiation field with a standard source, where the standard source is the center field intensity of the gamma radiation field of an ore with a known uranium content, and classify the uranium ore grade according to the uranium content.

[0044] The key factors causing the change of energy spectrum counts at each measuring point include: the content of uranium in the ore, the interaction between the radiation and the air, the detector and other media in the device. In this embodiment, the energy spectrum count rate in the energy range of [0.4MeV, 2.5MeV] is selected as the characteristic spectrum band of the reaction uranium series nuclide content.

[0045] In step S1, the gamma counting rate refers to the counting rate in the characteristic spectrum of gamma rays of the uranium ore.

[0046] In step S2, it is assumed that is the distance coordinate of the jth measuring point, j is the measuring point number, represents the net count rate of the characteristic spectrum of the i-th detector at the j-th measurement point, , K is the total number of measurement points, When the ore moves to the The net count rate of the characteristic spectrum of each measuring point of the i-th detector is connected in sequence, and the net count rate of the characteristic spectrum of each measuring point of the i-th detector is obtained. The counting curve of each detector is .

[0047] In this implementation case, two uranium ores with the same content are placed in parallel, and the simulated ores pass through the measurement area of ​​the array detection system at a uniform speed and are processed according to the above method. The count rate curve example results of each detector are as follows: Figure 2 As shown, Figure 2 The count rate curves of detector 3 and detector 5 coincide with each other, the count rate curves of detector 2 and detector 6 coincide with each other, and the count rate curves of detector 1 and detector 7 coincide with each other.

[0048] The process of establishing the γ radiation field intensity distribution numerical matrix according to the count rate curve is as follows: all the count rate curves are sorted according to the detector sequence, and combined to obtain the γ radiation field intensity distribution numerical matrix.

[0049] The process of decomposing the numerical matrix of the γ radiation field intensity distribution and obtaining the field intensity of a single ore (i.e. the uranium content of the ore) is as follows:

[0050] According to equation (1), the decomposition coefficient is obtained:

[0051] ;

[0052] in, represents the decomposition coefficient of the characteristic spectrum of the jth measuring point of the i-th detector, Indicates that the ore moves to the The count rate when the detector is directly above the

[0053] The physical meaning of the decomposition coefficient is: the counting rate when the ore moves to the top of the i-th detector The counting rate of each detector as the ore moves away from the detector ratio.

[0054] The decomposition coefficient is a parameter that describes the distribution of the field intensity of the gamma radiation field. It represents the ratio of the counting rate at different measuring points to the counting rate at the center of the detector. It is based on the principle of field source interchangeability in radioactivity measurement, that is, the field intensity at any position of the radiation field has a definite functional relationship with the central field intensity. The decomposition coefficient is a set of constants that are only related to the relative position of the source and the detector.

[0055] During the counting rate curve measurement process, the distance between the measuring points is determined according to the size of the uranium ore to be separated and the detector. When the ore passes through the detection area, all the counting rate curves form a γ radiation field intensity distribution numerical matrix. Then, according to the relative position between the ores, the decomposition coefficients corresponding to each area in the γ radiation field intensity distribution numerical matrix can be determined, and the equation group with the central field intensity of the γ radiation field as the unknown number is constructed, and the solution is obtained using the "least square method";

[0056] ;

[0057] in, is the central field strength of the γ radiation field of ore a, is the central field strength of the γ radiation field of ore b, represents the net count rate of the characteristic spectrum of the i-th detector at the j+1-th measurement point, It represents the net count rate of the characteristic spectrum of the i-th detector at the j+2-th measurement point, represents the decomposition coefficient of the characteristic spectrum of the j+1th measuring point of the i-th detector, Represents the decomposition coefficient of the characteristic spectrum of the j+2th measurement point of the i-th detector.

[0058] In this embodiment, according to the above method, the numerical matrix of the gamma radiation field intensity distribution is constructed for the obtained count rate curve, and then the decomposition coefficient is calculated according to equation (1): The calculation results are as follows Figure 3 As shown in the figure, the measured dual-source γ radiation field intensity distribution is as follows Figure 4 Then, the least square method is used to calculate according to equation (2), that is, the gamma radiation field strength of the dual source is decomposed into the gamma radiation field strength of two single sources. The decomposition result is as follows: Figure 5 and Figure 6 shown.

[0059] The embodiments described above are only descriptions of the preferred methods of the present application, and are not intended to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements made to the technical solutions of the present application by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present application.

Claims

1. A uranium ore grade separation method based on γ radiation field numerical matrix decomposition, characterized in that: The following steps are involved: Step S1: During the ore transportation process, the gamma count rate of the ore is measured by using the array detection system; Step S2: subtract the background from the ore gamma counting rate of each detector to obtain the net counting rate, and construct the counting rate curves respectively; Step S3: establishing a numerical matrix of the γ radiation field intensity distribution according to the count rate curve; Step S4: Decomposing the numerical matrix of the γ radiation field intensity distribution to obtain decomposition coefficients, constructing an equation group with the γ radiation field center intensity as an unknown variable according to the decomposition coefficients, and solving to obtain the center intensity of each γ radiation field; Step S5: Calculate the uranium content of each ore by comparing the center field intensity of the gamma radiation field with a standard source, where the standard source is the center field intensity of the gamma radiation field of an ore with a known uranium content, and classify the uranium ore grade according to the uranium content.

2. The uranium ore grade separation method based on γ radiation field numerical matrix decomposition according to claim 1 is characterized in that: The array detection system is composed of a plurality of detectors arranged in an array, a digital pulse multi-channel spectrum analyzer and a high-voltage supply module.

3. The uranium ore grade separation method based on γ radiation field numerical matrix decomposition according to claim 1 is characterized in that: In step S1, the ore gamma-ray count rate refers to the count rate in the characteristic spectrum of the uranium ore gamma-ray.

4. The uranium ore grade separation method based on γ radiation field numerical matrix decomposition according to claim 1 is characterized in that: The array detection system adopts an energy spectrum counting rate in the energy range of [0.4MeV, 2.5MeV].

5. The uranium ore grade separation method based on γ radiation field numerical matrix decomposition according to claim 1 is characterized in that: In step S2, it is assumed that is the distance coordinate of the jth measuring point, where j is the measuring point number; represents the net count rate of the characteristic spectrum of the i-th detector at the j-th measurement point, , K is the total number of measurement points, When the ore moves to the The net count rate of the characteristic spectrum of each measuring point of the i-th detector is connected in sequence, and the net count rate of the characteristic spectrum of each measuring point of the i-th detector is obtained. The counting curve of each detector is .

6. The uranium ore grade separation method based on γ radiation field numerical matrix decomposition according to claim 1 is characterized in that: In step S3, all count rate curves are sorted according to the order of the detectors and combined to obtain a numerical matrix of the γ radiation field intensity distribution.

7. The uranium ore grade separation method based on γ radiation field numerical matrix decomposition according to claim 5 is characterized in that: In step S4, the decomposition coefficient is obtained according to equation (1): ； in, represents the decomposition coefficient of the characteristic spectrum of the jth measuring point of the i-th detector, It represents the counting rate when the ore moves to the top of the i-th detector.

8. The uranium ore grade separation method based on γ radiation field numerical matrix decomposition according to claim 7 is characterized in that: In step S4, the equation group with the center field intensity of the gamma radiation field as an unknown variable is: ； in, is the central field strength of the γ radiation field of ore a, is the central field strength of the γ radiation field of ore b, represents the net count rate of the characteristic spectrum of the i-th detector at the j+1-th measurement point, It represents the net count rate of the characteristic spectrum of the i-th detector at the j+2-th measurement point, represents the decomposition coefficient of the characteristic spectrum of the j+1th measuring point of the i-th detector, Represents the decomposition coefficient of the characteristic spectrum of the j+2th measurement point of the i-th detector.

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