Detection analysis and prospecting indication method for altered minerals in granite type uranium deposit

Abstract

The invention relates to the field of geological mineral products, discloses a detection analysis and prospecting indication method for altered minerals in a granite type uranium deposit, and particularly relates to identification of components of red altered substances which are widely developed in Northern Guangdong cotton pit uranium deposits and research on prospecting indication significance of uranium deposits. Through the technologies of a polarizing microscope, a scanning electron microscope, laser Raman, an electron probe, LA-ICP-MS and the like, it is revealed that red substances in the cotton pit uranium deposit are mainly composed of hematite, goethite and a small amount of magnetite. Researches find that hematite in different forms is closely related to the enrichment degree of uranium, self-shaped and semi-self-shaped hematite is rich in uranium mineral inclusion, and disseminated hematite contains uranium in an adsorption form. According to the method, a theoretical basis is provided for prospecting of the granite type uranium ore, and particularly, the uranium mineralization potential is predicted through the crystal morphology of iron oxide (hydroxide) and element geochemical characteristics.

Description

Technical Field

[0001] The invention relates to the technical field of geological exploration, in particular to a detection and analysis method for altered minerals in granite-type uranium deposits and a prospecting indication method. Background Art

[0002] Granite-type uranium deposits are one of the important sources of uranium resources worldwide. In the formation process of uranium deposits, there is often a lot of hydrothermal alteration, mainly including "green" alteration and "red" alteration. Green alteration mainly includes hydromicitization and chloritization, and "red" alteration mainly includes hematite. However, these are all macroscopic descriptions. From a microscopic point of view, hydromicitization may represent a variety of clay minerals, and hematite may also include different types of iron oxides and iron hydroxides. Specifically, the indicative significance of different alteration minerals for uranium mineralization is different. Therefore, it is necessary to identify microscopic alteration minerals based on the macroscopic hydrothermal alteration characteristics. However, traditional mineralogical and geochemical analysis methods have limitations in accurately determining the composition of alteration minerals and their relationship with uranium mineralization. In addition, the trace elements and rare earth element characteristics rich in iron oxides (hydroxides) such as hematite, goethite and magnetite are of great significance for revealing the properties and evolution of uranium mineralization fluids.

[0003] In order to solve the above problems, the present invention provides a method for detecting, analyzing and prospecting altered minerals in granite-type uranium deposits. Summary of the invention

[0004] The purpose of the present invention is to provide a method for detecting and analyzing altered minerals in granite-type uranium deposits and for prospecting indication, so as to solve the problems in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for detecting and analyzing altered minerals in a granite-type uranium deposit and for prospecting indication, comprising the following steps:

[0006] a. Collect altered minerals and ore samples from granite-type uranium deposits;

[0007] b. Pre-treating the collected samples to prepare thin sheets or probe sheets;

[0008] c. Observe the samples under a microscope to preliminarily determine the type, morphology and symbiotic relationship of the altered minerals;

[0009] d. Detailed mineralogical and geochemical analysis of selected alteration minerals, including the use of scanning electron microscopy (SEM), laser Raman spectroscopy, electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS);

[0010] e. Based on the analysis results, identify and quantify the contents of major elements, trace elements and rare earth elements in altered minerals;

[0011] f. Analyze the genesis of altered minerals and their relationship with uranium mineralization, and further indicate the prospecting direction of uranium deposits.

[0012] Optionally, the mineralogical and geochemical analysis in step d specifically includes a detailed analysis of iron oxides (hydroxides) such as hematite, goethite and magnetite to explore their trace element and rare earth element characteristics.

[0013] Optionally, when analyzing the element content in the altered minerals in step e, special attention is paid to the content of granite-loving elements such as U, Mo, W and transition metal elements such as Cr, V, Co, Ni, and the distribution pattern of rare earth elements.

[0014] Optionally, in step f, the genesis of the altered minerals and their relationship with uranium mineralization are analyzed to identify the properties and evolution process of the uranium mineralization fluid, thereby providing a theoretical basis for further prospecting for uranium deposits.

[0015] Beneficial effects: Improve detection accuracy: Use advanced mineralogical, morphological and geochemical analysis techniques to accurately identify and determine the types and components of altered minerals, thereby improving detection accuracy.

[0016] Revealing the causal relationship: By analyzing the genesis of altered minerals, the intrinsic relationship between them and uranium mineralization is revealed, providing a new perspective for the study of the genesis of uranium deposits.

[0017] Guiding the direction of mineral exploration: Based on the geochemical characteristics of altered minerals, further indicating the prospecting direction of uranium deposits and improving the efficiency of mineral exploration. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Microscopic characteristics of iron oxides (hydroxides) in the Mianhuakeng uranium deposit (reflected light photograph);

[0019] Figure 2 Raman spectra of hematite and goethite in the Mianhuakeng uranium deposit;

[0020] Figure 3 Raman spectrum of a mixture of hematite and magnetite at the Mianhuakeng uranium deposit;

[0021] Figure 4 Mineralogical characteristics of iron oxides (hydroxides) in the Mianhuakeng uranium deposit (backscattered photograph);

[0022] Figure 5 Variable diagram of iron oxide (hydroxide) FeO and UO2 (a), Al2O3 (b) and SiO2 (c) in Mianhuakeng uranium deposit;

[0023] Figure 6 Illustration of rare earth element distribution of iron oxides in the Mianhuakeng uranium deposit. DETAILED DESCRIPTION

[0024] The following describes the preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0025] Example 1

[0026] A method for detecting and analyzing altered minerals in granite-type uranium deposits and for prospecting indication

[0027] The present invention provides a comprehensive detection and analysis method for altered minerals in granite-type uranium deposits and a prospecting indication method. The method combines a variety of advanced mineralogical and geochemical analysis techniques to accurately determine the composition of altered minerals, reveal their relationship with uranium mineralization, and provide a scientific basis for prospecting uranium deposits.

[0028] 1. Detailed technical solution

[0029] 1. Sample collection and pretreatment

[0030] Sample collection

[0031] Select geologically representative areas from granite-type uranium deposits for systematic sample collection. Considering the close relationship between altered minerals and uranium mineralization, focus should be placed on rock samples that show obvious alteration phenomena (such as red alteration). During the sampling process, it is necessary to record in detail the specific location of the sampling point, lithological characteristics, alteration phenomena and other information, which will provide indispensable basic data for subsequent analysis.

[0032] Sample pretreatment

[0033] The collected samples are carefully cleaned to thoroughly remove dirt and impurities on the surface. Subsequently, the samples are professionally ground in a laboratory environment. The samples will be carefully made into thin slices (mainly for observation under an optical microscope) and probe slices (specially for electron probe and laser ablation analysis). During the grinding process, it is necessary to ensure that the flatness of the sample meets the highest standards, so as to effectively avoid any errors in the subsequent analysis process. In addition, in order to fully ensure the accuracy and reliability of the analysis results, each sample needs to be strictly numbered and properly preserved to prevent confusion between samples.

[0034] (II) Preliminary mineralogical observation

[0035] Optical microscope observation

[0036] The carefully prepared thin sections are placed under an optical microscope for careful observation. By adjusting the magnification and lighting conditions of the microscope, the types and forms of the altered minerals and their symbiotic relationships can be clearly observed. In this process, the morphological characteristics of the minerals (such as color, luster, cleavage, etc.) and symbiotic relationships (such as inclusion relationships, filling relationships, etc.) can be recorded in detail. This information is of great reference value for subsequent analysis.

[0037] Preliminary determination and recording

[0038] During the observation process, it is necessary to record the morphological characteristics of each altered mineral in detail and preliminarily judge their potential relationship with uranium mineralization. For example, the enrichment of hematite may indicate the presence of uranium mineralization, because hematite is often one of the important carriers of uranium. At the same time, we should also pay close attention to the distribution of altered minerals, especially the distribution characteristics in bedding and cracks. This information will provide important clues and basis for subsequent analysis.

[0039] (III) Detailed mineralogical and geochemical analysis

[0040] Scanning electron microscopy (SEM) analysis

[0041] Advanced scanning electron microscopy technology is used to perform high-resolution imaging analysis on selected altered minerals. SEM technology can not only provide microscopic morphological information of altered minerals (such as particle size, shape, surface texture, etc.), but also accurately determine the elemental composition of the mineral surface through energy dispersive spectroscopy (EDS). Through SEM analysis, we can deeply observe the microstructural characteristics of iron oxides such as hematite and goethite, and preliminarily determine their elemental composition, laying the foundation for subsequent in-depth research.

[0042] Laser Raman spectroscopy

[0043] Laser Raman spectroscopy is used to further verify the types of altered minerals. By measuring the Raman scattering spectrum of minerals under laser irradiation and comparing it with known standard spectra, we can accurately identify the chemical composition and structural characteristics of minerals. Laser Raman spectroscopy has significant advantages in confirming the presence of iron oxides such as hematite and goethite, and can effectively eliminate the interference of other similar minerals to ensure the accuracy and reliability of the analysis results.

[0044] Electron Probe Mass Spectrometry (EPMA) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) Analysis

[0045] The electron probe analysis technique is used to accurately determine the content of major elements in altered minerals. Characteristic X-ray spectra are generated by bombarding the mineral surface with high-energy electron beams, and their wavelengths and intensities are measured to determine the type and content of the elements. At the same time, laser ablation inductively coupled technology (LA-ICP-MS) is used to accurately determine trace and rare earth elements in altered minerals. The determination of major, trace and rare earth elements is of great significance for revealing the origin and evolution process of altered minerals, and also provides valuable clues for subsequent prospecting work.

[0046] During the EPMA analysis, we need to pay special attention to the content changes of granite-loving elements such as U, Mo, and W, which are closely related to uranium mineralization. By comparing and analyzing the content characteristics of these elements, we can further infer the possible sources of ore-forming materials and provide important basis for revealing the genetic mechanism of uranium mineralization.

[0047] Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is an advanced micro-area in-situ analysis technology with wide applications in geology, mineralogy and geochemistry. This technology combines the high spatial resolution of the laser ablation system with the high sensitivity of inductively coupled plasma mass spectrometry (ICP-MS), enabling rapid and accurate analysis of trace elements in solid samples.

[0048] In the study of uranium deposits, LA-ICP-MS technology has shown its unique advantages. By conducting in-situ micro-area analysis of minerals in uranium deposits, the properties, sources and evolution of ore-forming fluids can be revealed, providing important information for the study of the genesis and mechanism of ore deposits.

[0049] Taking the Mianhuakeng uranium deposit in northern Guangdong as an example, researchers used LA-ICP-MS technology to analyze trace elements and rare earth elements in iron oxides (hydroxides). In this process, the laser beam is precisely focused on a tiny area of ​​the mineral sample, and the sample material is converted into aerosols through ablation, which are then introduced into the ICP-MS system for elemental analysis. This method not only realizes the quantitative detection of trace elements in minerals, but also retains the spatial distribution information of the samples, allowing researchers to accurately determine the occurrence state and distribution law of the elements.

[0050] In the study of the Mianhuakeng uranium deposit, the application of LA-ICP-MS technology revealed the enrichment characteristics of trace elements such as U, Mo, W, Cu, and Zn in iron oxides (hydroxides), as well as the distribution pattern of rare earth elements. This elemental information is of great significance for understanding the properties of the ore-forming fluids, the source of materials, and the hydrothermal process of the deposit. For example, through LA-ICP-MS analysis, it was found that hematite and goethite in the Mianhuakeng uranium deposit were enriched in granite-philic elements such as U, Mo, and W, suggesting that its ore-forming materials may mainly come from the surrounding granite. At the same time, the distribution pattern of rare earth elements also indicates the characteristics of CO32-rich ore-forming fluids.

[0051] In addition, LA-ICP-MS technology can also help researchers identify different forms of iron oxides (hydroxides) and explore their origins and their significance for uranium mineralization. For example, in the Mianhuakeng uranium deposit, LA-ICP-MS analysis revealed the differences in elemental composition between disseminated hematite and euhedral-subhedral hematite, indicating that they may have different origins and uranium enrichment mechanisms.

[0052] In summary, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) technology plays an important role in the study of uranium deposits. It can not only provide accurate trace element and rare earth element data, but also retain the spatial distribution information of samples, providing strong support for the study of the genesis and mineralization mechanism of ore deposits. With the continuous development and improvement of technology, LA-ICP-MS technology will play a more important role in future geological research.

[0053] In addition, we also need to pay attention to the distribution form of rare earth elements in altered minerals. Rare earth elements have unique geochemical properties, and their distribution form can reflect the properties and evolution process of ore-forming fluids. By analyzing the distribution form of rare earth elements in altered minerals, we can further understand the temperature, oxygen fugacity, salinity and other parameters of ore-forming fluids, providing key information for revealing the fluid source and evolution process of uranium mineralization.

[0054] (IV) Genesis analysis and prospecting indication

[0055] Analysis of the origin of altered minerals

[0056] Based on the detailed mineralogical and geochemical analysis results, combined with the regional geological background and geological characteristics of the ore deposits, the genesis of the altered minerals is analyzed in depth. By analyzing the formation conditions, evolution process and symbiotic relationship of the altered minerals with other minerals,

[0057] Analysis of the genesis of altered minerals is a key step in understanding the formation mechanism of uranium deposits and guiding prospecting. Based on the results of detailed mineralogical and geochemical analysis, we can further explore the genesis of altered minerals, as shown in the following examples.

[0058] Analysis of hematite genesis:

[0059] Formation environment: The formation of hematite is usually closely related to hydrothermal fluid activity. In granite-type uranium deposits, hematite may be formed in the process of oxidation of Fe2+ in hydrothermal fluid to Fe3+. This oxidation reaction is often accompanied by the reduction of U(VI) and the precipitation of uranium minerals.

[0060] Relationship between morphology and uranium mineralization: Euhedral and subeuhedral hematite is often rich in uranium mineral inclusions, indicating that it plays a key role in the uranium mineralization process. Disseminated hematite contains uranium in the form of adsorption, which may be related to the adsorption of uranium in the fluid on the surface of hematite.

[0061] Analysis of the origin of goethite:

[0062] Formation mechanism: The formation of goethite may be related to the leaching of oxidizing groundwater. During the flow of groundwater, the oxygen in the fluid may react with the iron in the rock to form goethite.

[0063] Geochemical characteristics: The geochemical characteristics of goethite, especially its trace element and rare earth element contents, can provide important information about the properties and evolution of the ore-forming fluids.

[0064] Analysis of the genesis of other altered minerals:

[0065] In addition to hematite and goethite, other alteration minerals may also exist in granite-type uranium deposits, such as purple-black fluorite, pyrite, microcrystalline quartz, chlorite, calcite, etc. The genesis and geochemical characteristics of these minerals are also of great significance for understanding the formation mechanism of uranium deposits.

[0066] Comprehensive cause analysis:

[0067] By comparing and analyzing the genetic characteristics of different altered minerals, we can further reveal the fluid source, evolution process and ore-forming material source of uranium mineralization. This information is crucial for guiding mineral prospecting.

[0068] Prospecting indication and direction determination

[0069] Based on the results of genetic analysis and geochemical characteristics research of altered minerals, we can further indicate the prospecting direction of uranium deposits.

[0070] Alteration mineral-rich areas:

[0071] Areas rich in altered minerals such as hematite and goethite are often potential uranium mineralization targets. These areas should be taken as key exploration targets for further analysis and verification.

[0072] Geochemical anomaly areas:

[0073] By analyzing the elemental geochemical characteristics of altered minerals (such as the changes in the content of granite-loving elements such as U, Mo, and W) and the distribution patterns of rare earth elements, we can identify geochemically anomalous areas that may hide undiscovered uranium ore bodies.

[0074] Comprehensive prospecting strategy:

[0075] Combining the regional geological structure, the characteristics of magmatic activity, and the genesis and geochemical characteristics of altered minerals, we can formulate a comprehensive prospecting strategy. Through drilling verification, tunnel exposure and other means, we can further determine the specific location and scale of the uranium ore body. The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0076] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for detecting and analyzing altered minerals in granite-type uranium deposits, characterized in that: The following steps are involved: a. Collect altered rock or ore samples from granite-type uranium deposits; b. Pre-processing the collected samples to prepare thin sheets and probe sheets; c. Use polarizing microscope to make preliminary mineralogical observation on the prepared thin sections to determine the altered mineral types, assemblages and paragenesis; d. Use scanning electron microscopy (SEM) to perform morphological analysis of altered minerals; e. Identify the composition of altered minerals by laser Raman spectroscopy; f. Use electron probe microprobe (EPMA) technology to analyze the content of major elements in altered minerals; g. Use laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) technology to analyze the trace elements and rare earth elements content of altered minerals. h. Analyze the genesis of altered minerals and their relationship with uranium mineralization, and indicate the direction of prospecting for uranium deposits.

2. The method for detecting, analyzing and prospecting altered minerals in a granite-type uranium deposit according to claim 1, characterized in that: It also includes identifying granite-loving elements such as U, Mo, and W enriched in altered minerals based on the results of EPMA and LA-ICP-MS analysis, thereby inferring the source of the mineralizing materials.

3. A method for identifying the main types of altered minerals in granite-type uranium deposits, comprising: The morphological characteristics of altered minerals were observed by SEM; Combined with the results of laser Raman spectroscopy analysis, the main types of altered minerals were identified, including but not limited to hematite, goethite and magnetite.

4. The method according to claim 3, characterized in that It also includes further distinguishing the morphology of hematite and identifying disseminated and euhedral-subhedral hematite.

5. A method for determining the origin of altered minerals in granite-type uranium deposits, characterized in that: include: Analyze the geochemical characteristics of altered minerals in different forms, including major elements, trace elements and rare earth elements; Determine the nature of the ore-forming fluid based on the rare earth element distribution pattern; Combining mineral paragenesis and fluid conditions, the formation mechanism of altered minerals can be inferred.

6. A method for prospecting and indicating granite-type uranium deposits, characterized in that: The different forms of altered minerals, especially hematite, are used as prospecting signs. The uranium contained in the impregnated hematite is stored in the form of adsorption, and the uranium contained in the sub-automorphic hematite is stored in the form of uranium mineral microinclusions, thus indicating the potential and distribution characteristics of uranium mineralization.

7. The method according to claim 6, characterized in that It also includes using the occurrence state and enrichment characteristics of uranium in altered minerals, combined with the regional geological background, to predict the scale of uranium ore bodies.

8. A method for improving the prospecting efficiency of granite-type uranium deposits, characterized in that: By using the detection and analysis technology described in any one of claims 1 to 7, key altered minerals and their characteristics can be quickly identified, thereby narrowing the scope of mineral exploration and improving the success rate of mineral exploration.

9. The method according to any one of claims 1 to 8, characterized in that The method is not only applicable to granite-type uranium deposits, but can also be extended to the detection and analysis of altered minerals and prospecting indication in other types of uranium deposits.

10. The method according to any one of claims 1 to 9, characterized in that The method combines multidisciplinary cross-analysis of mineralogy, petrography and geochemistry, providing a scientific basis for a deep understanding of the genesis of uranium deposits and guiding prospecting practices.

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