WO2024083132A1

WO2024083132A1 - Method for determining metallogenic mechanism of hydrothermal uranium ore

Info

Publication number: WO2024083132A1
Application number: PCT/CN2023/125058
Authority: WO
Inventors: 李子颖; 聂江涛; 郭建; 刘军港; 林锦荣; 秦明宽; 范洪海; 蔡煜琦; 唐湘生; 张玉燕; 刘文泉; 朱鹏飞; 黄宏业; 孙晔; 张杰林; 田明明; 黄志新; 刘鑫杨; 何升; 张明林
Original assignee: 核工业北京地质研究院
Priority date: 2022-10-19
Filing date: 2023-10-17
Publication date: 2024-04-25
Also published as: CN115356467A; CN115356467B

Abstract

The present invention relates to a method for analyzing rock mass in virtue of the physical and chemical properties of the rock mass, in particular to a method for determining the metallogenic mechanism of hydrothermal uranium ore. The method comprises: collecting an altered rock sample, an unaltered rock sample and a gangue mineral sample that are symbiotic with uranium ore in a hydrothermal uranium ore exploration area, wherein the gangue mineral sample at least comprises quartz, fluorite and calcite; performing component analysis on the altered rock sample, the unaltered rock sample and the gangue mineral sample to determine the components and redox characteristics of a metallogenic fluid; and determining the metallogenic mechanism of the hydrothermal uranium ore in the hydrothermal uranium ore exploration area on the basis of the components and the redox characteristics of the metallogenic fluid.

Description

Methods for determining the mineralization mechanism of hydrothermal uranium deposits

Technical Field

The present application relates to a method for analyzing a rock mass by means of its physical and chemical properties, and in particular to a method for determining the mineralization mechanism of hydrothermal uranium deposits.

Background technique

Determining the mineralization mechanism of uranium ore is the basis for uranium exploration. The mineralization fluid of hydrothermal uranium ore is an important carrier for the activation, migration, enrichment and unloading precipitation of ore-forming materials. Therefore, the mineralization mechanism of hydrothermal uranium ore can be determined with the help of mineralization fluid. In related technologies, fluid inclusions are usually used to analyze the mineralization fluid and then determine the mineralization mechanism. However, such methods are difficult to accurately determine the relevant characteristics of the original mineralization fluid, which makes it difficult to conduct a more accurate analysis of the mineralization mechanism of hydrothermal uranium ore.

Summary of the invention

In view of the above problems, the present application is proposed to provide a method for determining the mineralization mechanism of hydrothermal uranium ore that overcomes the above problems or at least partially solves the above problems.

An embodiment of the present application provides a method for determining the mineralization mechanism of a hydrothermal uranium ore, comprising: collecting altered rock samples, unaltered rock samples and gangue mineral samples coexisting with uranium ore in a hydrothermal uranium ore exploration area, wherein the gangue mineral samples include at least quartz, fluorite and calcite; performing component analysis on the altered rock samples, unaltered rock samples and gangue mineral samples to determine the components and redox characteristics of the ore-forming fluid; and determining the mineralization mechanism of the hydrothermal uranium ore in the hydrothermal uranium ore exploration area based on the components and redox characteristics of the ore-forming fluid.

The method for determining the mineralization mechanism of hydrothermal uranium ore according to the embodiment of the present application can more accurately determine the composition and redox characteristics of the original mineralizing fluid, thereby improving the accuracy of determining the mineralization mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of a method for determining a hydrothermal uranium mineralization mechanism according to an embodiment of the present application.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiment is one embodiment of the present application, not all embodiments. Based on the described embodiments of 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.

It should be noted that, unless otherwise defined, the technical terms or scientific terms used in this application should be the usual meanings understood by people with general skills in the field to which this application belongs. If the full text involves descriptions such as "first" and "second", the "first" and "second" descriptions are only used to distinguish similar objects, and cannot be understood as indicating or implying their relative importance, sequence, or implicitly indicating the number of technical features indicated. It should be understood that the data described by "first" and "second" can be interchangeable under appropriate circumstances. If "and/or" appears in the full text, its meaning includes three parallel solutions. Taking "A and/or B" as an example, it includes Solution A, or Solution B, or a solution that satisfies both A and B.

The embodiment of the present application provides a method for determining the reducibility of a hydrothermal uranium ore-forming fluid, referring to FIG1 , comprising:

Step S102: Collect altered rock samples, unaltered rock samples and gangue mineral samples coexisting with uranium ore in the hydrothermal uranium ore exploration area, wherein the gangue mineral samples at least include quartz, fluorite and calcite.

Step S104: Perform component analysis on the altered rock samples, the unaltered rock samples and the gangue mineral samples to determine the components and redox characteristics of the ore-forming fluid.

Step S106: Determine the hydrothermal uranium mineralization mechanism in the hydrothermal uranium exploration area based on the composition and redox characteristics of the ore-forming fluid.

Hydrothermal uranium ore refers to uranium-containing hydrothermal solutions of different origins and their mixed hydrothermal solutions, which are uranium-rich bodies formed by filling, replacement, etc. under suitable physical conditions and various favorable geological conditions. Hereinafter, these uranium-containing hydrothermal solutions and their mixed hydrothermal solutions are collectively referred to as ore-forming fluids. Common hydrothermal uranium deposits include granite-type uranium deposits, volcanic rock-type uranium deposits, etc.

During the growth of the ore body, part of the ore-forming fluid will be captured and encapsulated in the ore body to form fluid inclusions. The state of the ore-forming fluid when it is captured is determined by the pressure and temperature at the time of capture. However, after being captured, as the temperature and pressure decrease, it will present multiple phases, including gas, liquid, and solid. However, the ore-forming fluid will undergo various physical and chemical reactions during the mineralization process, resulting in the ore-forming fluid captured in the fluid inclusions not being able to fully represent the original ore-forming fluid.

To this end, this embodiment proposes to analyze the composition and redox characteristics of the ore-forming fluid with the help of altered rocks, unaltered rocks and gangue minerals, so as to more accurately determine the composition and redox characteristics of the original ore-forming fluid, and then more accurately determine the mineralization mechanism.

Specifically, in step S102, altered rock samples, unaltered rock samples, and gangue mineral samples coexisting with uranium ore in the hydrothermal uranium exploration area need to be collected.

Altered rock samples refer to rocks formed by water-rock interaction with ore-forming fluids in hydrothermal uranium exploration areas, while unaltered rock samples refer to fresh rocks that have not been altered in hydrothermal uranium exploration areas. Technical personnel in this field can distinguish altered rocks from unaltered rocks by observing the surface characteristics of rocks, and then collect altered rock samples and unaltered rock samples.

Gangue minerals refer to minerals composed of useless solid substances associated with useful minerals in ores (in this embodiment, useful minerals are uranium ore). Gangue minerals in this embodiment should include at least quartz, fluorite, and calcite, and each type of gangue mineral can be collected separately. As an example, in the process of collecting gangue minerals, for each type of gangue mineral, no less than 3 pieces need to be collected, each piece can be 3cm×6cm×9cm in size, and weigh no less than 1kg, to ensure that the samples used for component analysis can be successfully prepared.

In step S104, component analysis is performed on the altered rock samples, the unaltered rock samples, and the gangue mineral samples to determine the components and redox characteristics of the ore-forming fluid.

It can be understood that the difference between altered rocks and unaltered rocks is that the altered rocks are affected by the ore-forming fluid during the hydrothermal uranium mineralization process, resulting in differences in the content of some elements in the altered rocks and the unaltered rocks. Specifically, the content of some elements in the altered rocks is increased compared to the content of the elements in the unaltered rocks. The main reason for the increase is that some components of the ore-forming fluid migrate into the altered rocks during the mineralization process. Therefore, the components of the original ore-forming fluid can be determined with the help of the component analysis results of the altered rock samples and the unaltered rock samples. The specific method for component analysis of the altered rock samples and the unaltered rock samples can refer to the relevant test standards in this field, which will not be repeated here.

There are a large number of fluid inclusions in gangue mineral samples. Composition analysis of these gangue mineral samples is used to determine the gas, liquid, and solid components of the ore-forming fluids remaining in the fluid inclusions. This can effectively supplement and mutually verify the components of the ore-forming fluids determined by altered rock samples and unaltered rock samples. The combination of the two can more accurately and comprehensively restore the components of the original ore-forming fluids. Composition analysis of gangue mineral samples The specific method can also refer to the relevant test standards in the field, which will not be repeated here.

After the components of the ore-forming fluid are determined, the redox characteristics of the ore-forming fluid can be judged based on the determined components of the ore-forming fluid. For example, if the determined components of the ore-forming fluid include some typical reducing characteristic components, the ore-forming fluid can be determined to be reducing.

Next, in step S106, the hydrothermal uranium mineralization mechanism in the hydrothermal uranium exploration area can be determined according to the determined components and redox characteristics of the mineralizing fluid. The specific method of determining the mineralization mechanism with the help of the components and redox characteristics of the mineralizing fluid can be completed with reference to the relevant theories of hydrothermal uranium mineralization in the field. Since the components and redox characteristics of the original mineralizing fluid can be determined more accurately in this embodiment, the determined mineralization mechanism has higher accuracy.

In some embodiments, when determining the components of the ore-forming fluid, the element contents in the altered rock sample and the unaltered rock sample can be first determined based on the component analysis results, and then the migration of each element in the altered rock sample can be determined. Specifically, the migration of each element can be determined based on the difference in element contents between the altered rock sample and the unaltered rock sample, and finally the elements that migrate into the altered rock sample are determined as the components of the ore-forming fluid of the hydrothermal uranium ore.

In some embodiments, the migration of each element can be determined by separately determining the migration parameter M of each element in the altered rock sample. Specifically, the migration parameter M can be calculated using the following formula (1).
M＝(C1-C0)/C0 Formula (1)

Wherein, C1 is the content of an element in the altered rock sample, and C0 is the content of the element in the unaltered rock sample. When the migration parameter M is greater than 0, it is considered that the element has migrated into the altered rock sample. With the help of the above formula (1), the migration of each element can be judged more accurately and efficiently. At the same time, the migration parameter M calculated by the above formula (1) can also indicate the confidence of the judgment of the element migration to a certain extent. The higher the value, the higher the probability of the element migration.

In some embodiments, when collecting altered rock samples and unaltered rock samples, an altered zone in a hydrothermal uranium exploration area can be determined; and then multiple rock samples are continuously collected on the section of the altered zone, and the multiple rock samples include altered rock samples and unaltered rock samples. Specifically, altered rock samples can be collected from the edge to the center of the section where the altered zone is located, and unaltered rock samples can be collected outside the altered zone.

In such an embodiment, determining the migration of each element in the altered rock sample may specifically include: determining the comprehensive migration of each element on the profile. Compared with determining the element migration using only the element content in one altered rock sample, determining the element migration on the profile by using multiple altered rock samples continuously distributed on the altered zone is more convenient. Comprehensive migration profiles can increase accuracy.

In some embodiments, the comprehensive migration of elements on the profile of the alteration zone can be determined by separately determining the comprehensive migration parameter N of each element. The comprehensive migration parameter N is the sum of the migration parameters of multiple altered rock samples. Specifically, the following formula (2) can be used to calculate the comprehensive migration parameter N.
N＝M1+M2+…Mn Formula (2)

Wherein, M1-Mn are the migration parameters M of the n rock samples collected, and the migration parameters M can be calculated using the above formula (1). When calculating the migration parameters M of the n rock samples, the element content of the same unaltered rock sample can be used for calculation, or the element content of different unaltered rock samples can be selected for calculation, without limitation. In some other embodiments, other calculation formulas can be used to calculate the comprehensive migration parameter N, such as the average value, arithmetic mean value, etc. of the migration parameters M of multiple altered rock samples as the comprehensive migration parameter N, which will not be described in detail here.

After calculating the comprehensive migration parameter N using the above formula (2), if the comprehensive migration parameter N of an element is greater than the preset value, it can be considered that the element has migrated into the altered rock sample. It can be understood that the higher the preset value is set, the higher the accuracy is, but it may also cause some components to be omitted. Those skilled in the art can determine the preset value according to actual needs, and there is no limitation on this.

In some embodiments, when determining the element contents of altered rock samples and unaltered rock samples, the major element contents and trace element contents of the altered rock samples and unaltered rock samples can be determined respectively. In such embodiments, when determining the mineralizing fluid components, the major elements that migrate into the altered rock samples are determined as the major components of the mineralizing fluid, and the trace elements that migrate into the altered rock samples are determined as the trace components of the mineralizing fluid.

There are differences in the content analysis methods for major elements and trace elements in the art. For example, X-ray fluorescence spectrometer is usually used to measure major elements, and mass spectrometer is used to measure trace elements. For this reason, the major elements and trace elements are measured separately in this embodiment to ensure the efficiency and accuracy of the measurement. The specific distinction criteria for major elements and trace elements here can refer to the relevant standards in the art, and will not be repeated here.

The above describes a specific method for conducting component analysis on altered rock samples and unaltered rock samples to determine the components of ore-forming fluids. The following describes a specific method for conducting component analysis on gangue mineral samples to determine the components of ore-forming fluids.

In some embodiments, determining the components of the mineralizing fluid may also include: preparing each gangue mineral sample into an inclusion sheet sample, and then performing laser Raman analysis on the fluid inclusions in the inclusion sheet sample, and determining the gas phase component, liquid phase component and solid phase component of the mineralizing fluid based on the results of the laser Raman analysis.

The inclusion slice sample here can be a fluid inclusion slice well known to those skilled in the art. As described above, for each type of gangue mineral, no less than 3 pieces can be collected, and the size of each piece can be 3cm×6cm×9cm. The vein body can be delineated in each piece of gangue mineral collected. The vein body here refers to the development site of the gangue mineral. After the vein body is delineated, a sample of the inclusion slice can be collected at the vein body. The thickness can be 0.05-0.08mm. After double-sided polishing, 502 glue is used to glue the slices to make fluid inclusion slices. Similarly, no less than three fluid inclusion slices can be prepared for each type of gangue mineral. Those skilled in the art can prepare fluid inclusion samples of appropriate specifications and quantities in an appropriate manner according to the relevant requirements of the experimental equipment used in the actual component analysis, and there is no limitation on this.

In some embodiments, when performing laser Raman analysis on fluid inclusions in an inclusion sheet sample, multiple fluid inclusions can be first circled in the inclusion sheet sample, and the circled multiple fluid inclusions include at least fluid inclusions located in quartz, fluid inclusions located in fluorite, and fluid inclusions located in calcite to ensure the comprehensiveness of the analysis results, and then laser Raman analysis can be performed on each of the circled fluid inclusions separately.

Fluid inclusions can be circled under a microscope with the aid of a marking pen. Specifically, the distribution of fluid inclusions in the inclusion slice sample can be first determined using a microscope, and the fluid inclusions can be circled at locations where the fluid inclusions are concentrated and/or developed, thereby improving the efficiency of circled fluid inclusions.

In some embodiments, when delineating fluid inclusions, the diameter of the laser beam used in laser Raman spectroscopy needs to be taken into account to avoid delineating fluid inclusions that are too small (eg, smaller than the minimum diameter of the laser beam) and thus affecting the accuracy of the component analysis results.

In some embodiments, when multiple fluid inclusions are delineated in the inclusion sheet sample, the stability of the gas phase components in the delineated fluid inclusions can be determined using a microscope. If the gas phase components migrate, the fluid inclusions are re-delineated. It is understandable that if the gas phase components in the inclusions migrate during the laser Raman spectroscopy analysis, the analysis results may be inaccurate or even fail. Therefore, in this embodiment, after delineating the fluid inclusions, the fluid inclusions are continuously observed under a microscope for a period of time to determine the stability of the delineated fluid inclusions, so as to ensure the accuracy of the analysis results.

In some embodiments, when delineating multiple fluid inclusions in an inclusion sheet sample, it is necessary to delineate within a preset depth range of the inclusion sheet sample, and the preset depth range can be determined by referring to the parameters of the laser Raman spectrum used to ensure the accuracy of the analysis results. For different types of gangue minerals, the appropriate development depth may be different. For example, for calcite, its optical properties are relatively special, and inclusions shallower than 20 μm need to be selected as target inclusions to prevent the laser Raman spectrum curve from drifting and covering up the spectral peaks of the reducing characteristic components.

In the embodiments described above, laser Raman spectroscopy is used to perform component analysis on individual fluid inclusions in the gangue mineral sample to determine the composition of the ore-forming fluid. In some other embodiments, in addition and/or as an alternative, all the components in the fluid inclusions of the gangue mineral sample can be released and analyzed.

Specifically, in some embodiments, the collected gangue samples can be prepared into granular single mineral samples, and then the ion composition analysis of the granular single mineral samples is performed to determine the components of the ore-forming fluid. The single mineral sample refers to a sample containing only one type of gangue. In this embodiment, granular single mineral samples of quartz, style, and calcite need to be prepared separately.

Specifically, a suitable crushing device can be used to crush the collected gangue minerals, such as a jaw crusher. After the crushing is completed, the crushed gangue minerals can be screened. The screening can be completed using a standard sieve. As an example, an 80-mesh standard sieve can be used for screening. Then, the gangue can be selected from the sieved gangue minerals. It can be understood that the gangue minerals inevitably include some other impurities in addition to the gangue, so selection is required. The selection can be assisted by a binocular stereoscope and other devices. The purity of the gangue in the granular single mineral sample obtained after the selection should reach more than 99%, and the weight of each granular single mineral sample should be at least 1g to ensure that it contains a sufficient number of inclusions. Those skilled in the art can specifically choose what specifications of powder to prepare the gangue mineral according to the relevant requirements of the experimental equipment used in the actual component analysis, and there is no restriction on this.

In some embodiments, if it is necessary to prepare inclusion sheet samples and granular single mineral samples at the same time, the gangue mineral samples remaining after preparing the inclusion sheet samples can be used to prepare the granular single mineral samples, thereby reducing the amount of gangue minerals that need to be collected and improving efficiency.

In some embodiments, performing ion component analysis on a granular single mineral sample may specifically include: using a bursting method to release ion components in fluid inclusions of the granular single mineral sample; and performing ion component analysis on the ion components by means of ion chromatography. The bursting method can effectively release ion components in each fluid inclusion in the powdered sample, thereby completing ion component analysis.

It can be understood that in this embodiment, the components of all fluid inclusions in a single mineral sample can be analyzed at one time, which can effectively supplement and mutually verify the component analysis results of the above-mentioned laser Raman spectroscopy. The use of these two component analysis methods at the same time can further improve the comprehensiveness of the analysis. Of course, technical personnel in this field can also choose one of the methods to perform component analysis on the gangue mineral sample according to actual conditions.

In some embodiments, as described above, the redox characteristics of the ore-forming fluid can be determined based on the components of the ore-forming fluid. If the components of the ore-forming fluid include at least one reducing characteristic component, then the ore-forming fluid is determined to be The reducing characteristic components here can be determined by those skilled in the art based on the geochemical characteristics of the hydrothermal uranium exploration area, or based on historical experience, and there is no limitation on this.

In some embodiments, _the above-mentioned reducing characteristic components may specifically include _SO2 , CO, NO, _H2 , _H2S , _C2H6 , _C2H4 _{, C3H8} _, _C6H6 _, _FeS2 _, etc.

The present invention is described in detail above with reference to the accompanying drawings and embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. The contents not described in detail in the present invention can adopt the existing technology.

Claims

Methods for determining the mechanism of hydrothermal uranium mineralization include:

Collect altered rock samples, unaltered rock samples and gangue mineral samples coexisting with uranium ore in the hydrothermal uranium ore exploration area, wherein the gangue mineral samples include at least quartz, fluorite and calcite;

Performing component analysis on the altered rock sample, the unaltered rock sample and the gangue mineral sample to determine the components and redox characteristics of the ore-forming fluid;

Determining the hydrothermal uranium mineralization mechanism in the hydrothermal uranium exploration area based on the composition and redox characteristics of the ore-forming fluid; wherein determining the composition of the ore-forming fluid comprises:

Performing component analysis on the altered rock sample and the unaltered rock sample to determine the element contents of the altered rock sample and the unaltered rock sample;

Determining the migration of each element in the altered rock sample, wherein the migration of each element is determined based on the difference in element content between the altered rock sample and the unaltered rock sample;

determining the elements that migrate into the altered rock sample as components of the ore-forming fluid;

Wherein, collecting the altered rock sample and the unaltered rock sample comprises:

Determine the alteration zones in the hydrothermal uranium prospecting area;

Continuously collecting a plurality of rock samples on the cross section of the altered zone, wherein the plurality of rock samples include the altered rock samples and the unaltered rock samples;

Determining the migration of each element in the altered rock sample includes:

Determine the migration parameter M of each element in the altered rock sample respectively, the migration parameter M=(C1-C0)/C0, wherein C1 is the element content of the altered rock sample, and C0 is the element content of the unaltered rock sample;

Determine the comprehensive migration of each element on the profile, and determine the comprehensive migration parameter N of each element respectively. The comprehensive migration parameter N is the sum of the migration parameters M of multiple altered rock samples. When the comprehensive migration parameter N is greater than a preset value, it is considered that the element has migrated into the altered rock sample.
The method of claim 1, wherein determining the element contents of the altered rock sample and the unaltered rock sample comprises:

Determining the major element content and the trace element content of the altered rock sample and the unaltered rock sample;

Determining the composition of the ore-forming fluid comprises:

The major element that migrated into the altered rock sample is determined as the major component of the ore-forming fluid. The trace elements in the altered rock samples are determined to be trace components of the ore-forming fluid.
The method of claim 1, wherein determining the composition of the ore-forming fluid further comprises:

preparing each of the gangue mineral samples into inclusion sheet samples respectively;

performing laser Raman analysis on the fluid inclusions in the inclusion sheet sample;

Determining the composition of the ore-forming fluid comprises:

The gas phase components, liquid phase components and solid phase components of the ore-forming fluid are determined based on the results of the laser Raman analysis.
The method according to claim 3, wherein performing laser Raman analysis on the fluid inclusions in the inclusion sheet sample comprises:

Delineating a plurality of fluid inclusions in the inclusion sheet sample, wherein the plurality of fluid inclusions delineated include at least fluid inclusions located in quartz, fluid inclusions located in fluorite, and fluid inclusions located in calcite;

Laser Raman analysis was performed on each of the identified fluid inclusions.
The method according to claim 4, wherein delineating a plurality of fluid inclusions in the inclusion sheet sample comprises:

A plurality of fluid inclusions are delineated within a preset depth range of the inclusion sheet sample.
The method of claim 1, wherein determining the composition of the ore-forming fluid further comprises:

preparing the gangue mineral sample into a granular single mineral sample;

performing composition analysis on the granular single mineral sample;

Determining the composition of the ore-forming fluid comprises:

The components of the ore-forming fluid are determined based on the component analysis results.
The method according to claim 6, wherein preparing the gangue mineral sample into a granular single mineral sample comprises:

crushing the gangue mineral sample and sieving it using a sieve of a predetermined size;

Quartz, fluorite and calcite are selected from the sieved gangue mineral sample to obtain the granular single mineral sample.
The method according to claim 7, wherein the component analysis of the granular single mineral sample is The analysis includes:

Using a detonation method to release ionic components in fluid inclusions of the granular monomineral sample;

The ion components are analyzed for ion composition by means of ion chromatography.
The method according to any one of claims 1 to 8, wherein determining the redox characteristics of the ore-forming fluid comprises:

The redox characteristics of the ore-forming fluid are determined based on the components of the ore-forming fluid, wherein if the components of the ore-forming fluid include at least one reducing characteristic component, the ore-forming fluid is determined to be reducing.
The method according to claim 9, wherein the reducing characteristic component comprises:
SO 2 , CO, NO, H 2 , H 2 S, C 2 H 6 , C 2 H 4 , C 3 H 8 , C 6 H 6 , FeS 2 .