Estimation method of precipitation temperature of uraninite in granite type low temperature hydrothermal uranium deposit

Abstract

Embodiments of the present application relate to the application of thermal methods to test or analyze materials, and in particular to a method for estimating the precipitation temperature of pitchblende in granite-type low-temperature hydrothermal uranium deposits, which can include the following steps: S10: collecting vein ore samples containing primary pitchblende veins in the survey area; S20: processing the vein ore samples to obtain calcite single mineral samples and fluorite single mineral samples; S30: analyzing the calcite single mineral and fluorite single mineral samples to determine the carbon isotope composition of the calcite single mineral samples and the carbon isotope composition of the fluid inclusions in the fluorite single mineral samples; S40: determining the carbon isotope equilibrium temperature according to the carbon isotope composition; S50: determining the precipitation temperature of pitchblende in granite-type low-temperature hydrothermal uranium deposits according to the carbon isotope equilibrium temperature. The method provided by the embodiments of the present application can determine the precipitation temperature of pitchblende through the carbon isotope composition of the coeval calcite and fluorite, and the determined precipitation temperature is accurate and reliable.

Description

Technical Field

[0001] The embodiments of this application relate to the application of thermal methods for testing or analyzing materials, specifically to a method for estimating the precipitation temperature of pitchblende in granite-type low-temperature hydrothermal uranium deposits. Background Technology

[0002] The statements herein are provided merely as background information in relation to the present invention and do not necessarily constitute prior art.

[0003] Granite-type uranium deposits are one of the main types of uranium deposits in my country. Most of these deposits are hydrothermal uranium deposits. Pitchblende is the main mineral in granite-type uranium deposits. Pitchblende is not only the main mineral raw material for extracting uranium, but also an important mineral for prospecting. Summary of the Invention

[0004] A brief overview of this application is provided below to offer a basic understanding of certain aspects thereof. It should be understood that this overview is not an exhaustive summary of the application. It is not intended to identify key or essential parts of the application, nor is it intended to limit its scope. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description that follows.

[0005] This application provides a method for estimating the precipitation temperature of pitchblende in granite-type low-temperature hydrothermal uranium deposits, comprising the following steps: S10: collecting vein-like ore samples containing primary pitchblende veins in the exploration area, wherein the samples also contain calcite and purplish-black fluorite that mineralized concurrently with the pitchblende; S20: processing the vein-like ore samples to obtain calcite single-mineral samples and fluorite single-mineral samples; S30: analyzing the calcite single-mineral samples and fluorite single-mineral samples to determine the carbon isotope composition in the calcite single-mineral sample and the carbon isotope composition of fluid inclusions in the fluorite single-mineral sample; S40: determining the carbon isotope equilibrium temperature based on the carbon isotope composition; S50: determining the precipitation temperature of pitchblende in granite-type low-temperature hydrothermal uranium deposits based on the carbon isotope equilibrium temperature.

[0006] The method provided in the embodiments of this application can determine the carbon isotope equilibrium temperature by using the carbon isotope composition of calcite and fluorite from the same mineralization period as pitchblende, and determine the precipitation temperature of pitchblende in granite-type low-temperature hydrothermal uranium deposits based on the carbon isotope equilibrium temperature, and the obtained precipitation temperature is accurate and reliable. Attached Figure Description

[0007] Other objects and advantages of this application will become apparent from the following description of embodiments of this application with reference to the accompanying drawings, and will help to provide a comprehensive understanding of this application.

[0008] Figure 1This is a schematic diagram illustrating the process of estimating the precipitation temperature of pitchblende in granite-type low-temperature hydrothermal uranium deposits, provided in an embodiment of this application.

[0009] Figure 2 This is a schematic diagram illustrating the process of collecting vein-like ore samples in a survey area, as provided in an embodiment of this application.

[0010] Figure 3a This is a schematic cross-sectional view of a vein ore sample from the Xincun uranium deposit provided in an embodiment of this application.

[0011] Figure 3b This is a schematic diagram of the structure of the optical sheet of the Shinchon uranium deposit provided in an embodiment of this application.

[0012] Explanation of reference numerals in the attached figures:

[0013] 301. Calcite; 302. Pitchblende; 303. Fluorite.

[0014] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are shown only in a schematic manner without affecting the reader's understanding. Detailed Implementation

[0015] Exemplary embodiments of the invention will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of actual implementations are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the development of any such actual embodiment to achieve the developer's specific goals, such as complying with constraints related to the system and business, and these constraints may vary depending on the implementation. Furthermore, it should be understood that while development work can be very complex and time-consuming, such development work is merely a routine task for those skilled in the art who benefit from the content of this application.

[0016] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the device structure and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0017] For hydrothermal deposits, the composition of the ore-forming hydrothermal fluid, the content of different components, and the temperature of the hydrothermal fluid directly affect the mineralization process. The precipitation temperature can also affect the solubility and migration form of different components in the ore-forming hydrothermal fluid. Therefore, the precipitation temperature has an important influence on the mineralization process of hydrothermal deposits and is an important parameter of hydrothermal mineralization.

[0018] Currently, the precipitation temperature of pitchblende is mostly determined using fluid inclusion hot-and-cold stage microthermography and hydrothermal alteration thermometry. However, both methods have significant drawbacks and limitations, making it difficult to accurately determine the precipitation temperature.

[0019] The hot-and-cold stage microthermometry method for fluid inclusions requires the fabrication of fluid inclusion slides. Furthermore, at low temperatures, fluid inclusions are in a liquid phase, making microthermometry difficult. Moreover, because the experimental environment of the hot-and-cold stage differs from the high-pressure underground environment during ore formation, pressure correction is required when determining the precipitation temperature. This method is not only time-consuming and labor-intensive, but also cumbersome. Since the precipitation temperature is determined by observing changes in the fluid phase within the fluid inclusions, it requires highly specialized knowledge and experience from technicians to obtain accurate data. The obtained temperatures are susceptible to subjective influence, lacking objectivity and accuracy.

[0020] When using hydrothermal alteration thermometers to obtain precipitation temperatures, it is necessary to find minerals that are from the same mineralization period as the uranium deposit, whose genesis is related to hydrothermal activity, and which are suitable for use with mineral thermometers. However, for granitic uranium deposits, the associated minerals from the same mineralization period are mostly fluorite, calcite, and other minerals that are not suitable for use with mineral thermometers. Even for chloritized and illitetized hydrothermal alteration minerals that are suitable for use with mineral thermometers, the temperatures obtained by the hydrothermal alteration thermometer method reflect the temperature of hydrothermal alteration before mineralization, rather than the precipitation temperature of pitchblende during the mineralization period.

[0021] To address at least one aspect of the aforementioned technical problems, embodiments of this application provide a method for estimating the precipitation temperature of pitchblende in granite-type low-temperature hydrothermal uranium deposits, such as... Figure 1 As shown, it illustrates a schematic diagram of the process for estimating the precipitation temperature of pitchblende in granite-type low-temperature hydrothermal uranium deposits provided by an embodiment of this application.

[0022] The method may include the following steps: S10: Collect vein-like ore samples containing primary pitchblende veins in the survey area, wherein the samples also contain calcite and purplish-black fluorite that mineralized concurrently with the pitchblende; S20: Process the vein-like ore samples to obtain calcite single-mineral samples and fluorite single-mineral samples; S30: Analyze the calcite single-mineral samples and fluorite single-mineral samples to determine the carbon isotope composition in the calcite single-mineral sample and the carbon isotope composition of the fluid inclusions in the fluorite single-mineral sample; S40: Determine the carbon isotope equilibrium temperature based on the carbon isotope composition; S50: Determine the pitchblende precipitation temperature of granite-type low-temperature hydrothermal uranium deposits based on the carbon isotope equilibrium temperature.

[0023] The method provided in the embodiments of this application can determine the carbon isotope equilibrium temperature by analyzing the carbon isotope composition of calcite and fluorite from the same mineralization period as pitchblende, and then determine the precipitation temperature of pitchblende in granite-type low-temperature hydrothermal uranium deposits based on the carbon isotope equilibrium temperature. The obtained precipitation temperature is accurate and reliable. Furthermore, the precipitation temperature estimation method provided in the embodiments of this application is less affected by subjective human factors, and the determined precipitation temperature has high reliability.

[0024] In some embodiments, step S40 may further include the following steps: S41: performing carbon isotope equilibrium fractionation calculations on the carbon isotope composition of the calcite single mineral sample and the carbon isotope composition of the fluid inclusions in the fluorite single mineral sample to determine the temperature of carbon isotope equilibrium.

[0025] The carbon in calcite is in the form of CO3 in the mineral CaCO3 crystals. 2- The carbon in fluorite exists in the form of CO2 within fluid inclusions; therefore, it can be determined based on CO3. 2- Carbon isotope equilibrium fractionation calculations were performed using the fractionation coefficient and fractionation equation of CO2 to determine the temperature of carbon isotope equilibrium. Since calcite and purplish-black fluorite are symbiotic, the carbon isotopes in the fluorite fluid inclusions can reach equilibrium with those in the calcite mineral. Therefore, carbon isotope equilibrium fractionation calculations can be performed, providing a prerequisite for estimating the precipitation temperature of pitchblende using carbon isotope equilibrium calculations.

[0026] In some embodiments, in step S41, carbon isotope equilibrium fractionation calculation can be performed as follows: T(°C) = 20 + (10.17 - ε(calcite-fluorite)) / 0.0063, where T can represent the temperature of carbon isotope equilibrium, and ε(calcite-fluorite) can represent the difference between the carbon isotope composition in the calcite single mineral sample and the carbon isotope composition of the fluid inclusions in the fluorite single mineral sample.

[0027] In some embodiments, the carbon isotope equilibrium temperature determined in step S50 is the precipitation temperature of pitchblende in granite-type low-temperature hydrothermal uranium deposits. Since fluorite and calcite are minerals that formed during the same period as pitchblende and are associated with it, the temperature at which fluorite and calcite reach carbon isotope equilibrium can represent the precipitation temperature of pitchblende.

[0028] The estimation method provided in the embodiments of this application is relatively simple to operate, does not require technicians with strong work experience, is less affected by personal subjective factors, and the precipitation temperature obtained is relatively objective.

[0029] In some embodiments, such as Figure 2The diagram illustrates the process of collecting vein-like ore samples in a survey area according to an embodiment of this application. Step S10 may further include the following steps: S11: When collecting samples, determine the radioactivity of the samples; S12: For samples with high radioactivity, determine that they belong to pitchblende; S13: For samples that have been determined to be pitchblende, determine the mineral types and structural relationships; S14: Determine that pitchblende samples containing calcite and purplish-black fluorite are vein-like ore samples.

[0030] In some embodiments, step S14 may further include the following: preparing a probe sheet from the collected sample to determine the structural relationship between calcite, purplish-black fluorite and pitchblende; based on the structural relationship, the pitchblende sample including calcite and purplish-black fluorite may be determined to be a vein ore sample.

[0031] The samples obtained through the above steps are more likely to be identified as vein ore samples, and the samples identified in the above manner are more likely to be reliable for subsequent temperature estimation.

[0032] In some embodiments, in step S11, the intensity of radioactivity can be determined using a gamma radiation meter.

[0033] In some embodiments, in step S14, the structural relationship between calcite, purplish-black fluorite and pitchblende can be as follows: when pitchblende coexists with fluorite and calcite and crystallizes simultaneously, the three minerals will crystallize and precipitate in a regular manner in a certain direction and in a certain order, and pitchblende will be sandwiched between fluorite and calcite.

[0034] In some embodiments, step S20 may further include the following steps: S21: cutting a smooth section of the vein-like ore sample; S22: micro-drilling the smooth section to obtain a single fluorite mineral sample in association with purplish-black fluorite, pitchblende, and calcite.

[0035] In some embodiments, in step S21, the vein-shaped ore sample can be cut along the direction perpendicular to the vein and ground into a smooth slide without a cover glass, which can be observed under a microscope.

[0036] In some embodiments, step S22 may further include the following: determining the borehole diameter of the micro-drill based on the grain size of the target purplish-black fluorite mineral in the cut section. Processing the cut section in this way yields a single fluorite mineral sample, facilitating subsequent processing.

[0037] In some embodiments, in step S22, after micro-drilling the light sheet, calcite single mineral samples and fluorite single mineral samples can be obtained through processes such as washing, heavy liquid and manual selection with binoculars, wherein the purity of calcite and fluorite in the calcite single mineral samples and fluorite single mineral samples is >99%.

[0038] In some embodiments, step S30 may include the following: collecting the fluorite single mineral sample obtained using step S22 to a predetermined size, and performing analysis on the fluorite single mineral sample of the predetermined size.

[0039] In some embodiments, in step S30, when determining the carbon isotope composition of a fluorite single mineral sample, a heating explosion method can be used to extract the fluid from the fluid inclusions in the fluorite; when determining the carbon isotope composition of a calcite single mineral sample, the calcite single mineral sample can be dissolved with orthophosphoric acid and carbon dioxide can be extracted for analysis, and the carbon isotope composition can be determined using a MAT-253 gas isotope mass spectrometer.

[0040] In some embodiments, during step S30, when analyzing a single fluorite mineral sample, only CO2 in the fluid inclusions of the single fluorite mineral sample can be extracted to determine the carbon isotopes of the fluid inclusions. Extracting only CO2 from the fluid inclusions of the single fluorite mineral sample while removing other gaseous components, including methane, can improve the accuracy of the temperature estimation results.

[0041] The following section uses the Xincun deposit as an example to explain in detail the process of estimating the precipitation temperature of pitchblende using the estimation method provided in the embodiments of this application.

[0042] First, vein-like ore samples containing pitchblende, as well as calcite and fluorite mineralized concurrently with pitchblende, were collected from the Xincun deposit. Figure 3a As shown, it illustrates a cross-sectional schematic diagram of a vein ore sample from the Xincun uranium deposit provided in an embodiment of this application. The cross-section of the vein ore sample shows visible dark green veins of vein ore, purplish-black fluorite 303, and calcite 301.

[0043] Next, the obtained vein-like ore samples are processed to prepare cut sections, which can be observed under a microscope. Figure 3bThe diagram shows a schematic representation of the structure of the Xincun uranium deposit provided in an embodiment of this application. Observation reveals that the vein's periphery contains fluorite 303, followed by pitchblende 302-fluorite 303 assemblages, and then calcite 301-purple-black fluorite 303 assemblages. Calcite 301 is located in the middle of the vein and also contains purplish-black fluorite 303. According to the spatial distribution of different mineral veins, the mineral precipitation sequence is fluorite 303, pitchblende 302, and calcite 301. This regular vein crystallization sequence geologically indicates that pitchblende 302, fluorite 303, and calcite 301 are products of crystallization and precipitation from the same hydrothermal activity, representing a mineral symbiotic relationship.

[0044] Next, the single mineral samples of calcite and fluorite were analyzed to determine their carbon isotope composition. The example carbon isotope data of calcite and fluorite are shown in Table 1 below.

[0045] Table 1. Example data on carbon isotopes in calcite and fluorite.

[0046]

[0047] Next, based on the carbon isotope composition of calcite and fluorite, the equilibrium temperature of carbon isotopes was calculated. Without considering the error of the original relation, the calculated equilibrium temperature of carbon isotopes was 40℃-80℃.

[0048] Finally, the precipitation temperature of pitchblende in the Xincun uranium deposit can be determined to be 40℃-80℃.

[0049] Regarding the embodiments of this application, it should also be noted that, without conflict, the embodiments of this application and the features in the embodiments can be combined with each other to obtain new embodiments.

[0050] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A method for estimating the precipitation temperature of pitchblende in granite-type low-temperature hydrothermal uranium deposits, characterized in that, It includes the following steps: S10: Collect vein-shaped ore samples containing primary pitchblende veins in the survey area, wherein the samples also contain calcite and purplish-black fluorite that were formed at the same time as the pitchblende. S20: Process the vein-like ore sample to obtain a calcite single mineral sample and a fluorite single mineral sample. S30: Analyze the calcite single mineral sample and the fluorite single mineral sample to determine the carbon isotope composition of the calcite single mineral sample and the carbon isotope composition of the fluid inclusions in the fluorite single mineral sample. S40: Determine the carbon isotope equilibrium temperature based on the carbon isotope composition. S50: Determine the precipitation temperature of pitchblende in the granite-type low-temperature hydrothermal uranium deposit based on the carbon isotope equilibrium temperature; S41: Perform carbon isotope equilibrium fractionation calculations on the carbon isotope composition of the calcite single mineral sample and the carbon isotope composition of the fluid inclusions in the fluorite single mineral sample to determine the temperature of carbon isotope equilibrium. In step S41, the carbon isotope equilibrium fractionation calculation is performed as follows: T(℃) = 20 + (10.17 - ε(calcite-fluorite)) / 0.0063, where T represents the temperature of carbon isotope equilibrium and ε(calcite-fluorite) represents the difference between the carbon isotope composition in the calcite single mineral sample and the carbon isotope composition of the fluid inclusions in the fluorite single mineral sample. The determined carbon isotope equilibrium temperature is the pitchblende precipitation temperature of the granite-type low-temperature hydrothermal uranium deposit.

2. The method according to claim 1, characterized in that, Step S10 also includes the following steps: S11: When collecting samples, a radioactivity measurement is performed on the samples; S12: For samples with high radioactivity, it is determined that they belong to pitchblende. S13: To determine that it is pitchblende, identify the types of its minerals and their structural relationships; S14: The pitchblende sample containing calcite and purplish-black fluorite was identified as a vein ore sample.

3. The method according to claim 2, characterized in that, Step S14 also includes: The collected samples were made into probe sheets to determine the structural relationship between the calcite, the purplish-black fluorite and the pitchblende. Based on the structural relationship, the pitchblende sample including calcite and purplish-black fluorite was determined to be a vein ore sample.

4. The method according to claim 1, characterized in that, Step S20 also includes: S21: Cut the vein-like ore sample into a polished section; S22: Micro-drilling is performed on the light sheet to obtain a single mineral sample of fluorite coexisting with the purplish-black fluorite, the pitchblende, and the calcite.

5. The method according to claim 4, characterized in that, In step S22, The borehole diameter of the micro-drill is determined based on the particle size of the target purplish-black fluorite in the optical disc.

6. The method according to claim 4, characterized in that, Collect the fluorite single mineral sample obtained in step S22 to a predetermined size, and analyze the fluorite single mineral sample of the predetermined size.

7. The method according to claim 1, characterized in that, In step S30, When analyzing the fluorite single mineral sample, only CO2 is extracted from the fluid inclusions in the fluorite single mineral sample to determine the carbon isotopes of the fluid inclusions in the fluorite single mineral sample.

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