A sandstone-type uranium ore plug-shaped core in-situ leaching test method and system

Abstract

The present invention discloses an in-situ leaching test method and system for sandstone-type uranium ore plug-shaped cores, which relates to the technical field of uranium ore leaching seepage test. The method comprises: obtaining a first parameter, a second parameter, a chemical element content, and a pore parameter before leaching based on the uranium ore core; using a preset leaching method, performing an in-situ leaching test on the plug-shaped core, and drawing a permeability change curve; determining the first parameter, the second parameter, the chemical element content, and the pore parameter after leaching; judging whether the preset leaching method meets the preset leaching requirements based on the permeability change curve and the pore parameters before and after leaching; and determining the changes in each parameter based on the first parameter, the second parameter, and the chemical element content before and after leaching. The present invention can not only realize in-situ leaching of sandstone-type uranium ore plug-shaped cores, simulate the in-situ leaching process of uranium in actual ore layers, but also meet the permeability test requirements of the plug-shaped cores during the leaching process.

Description

Technical Field

[0001] The invention relates to the technical field of uranium ore leaching and seepage testing, in particular to an in-situ leaching test method and system for a sandstone-type uranium ore plug-shaped core. Background Art

[0002] In-situ uranium leaching (ISL) is a mining process that involves preparing a specific amount of leaching agent on the surface and injecting it into the underground ore body through a drilled hole. The leaching solution selectively dissolves the uranium in the ore during its seepage underground. The resulting leachate is then lifted to the surface, where it is extracted and recovered. Due to the complex geological characteristics of uranium mines, the invisibility of underground fluid flow and leaching reactions, the ISL process is unpredictable. This requires extensive research under indoor experimental conditions to understand the leaching properties and seepage characteristics of uranium ores.

[0003] Uranium ore leaching tests typically use loose uranium ore samples. Specifically, field-collected bulk uranium ore samples are crushed to their natural size or ground to the desired particle size. These tests typically include agitation leaching and column leaching. Agitation leaching tests use a fixed liquid-to-solid ratio or other test conditions, including leaching agent type, concentration, and temperature, over a shorter leaching time to examine the uranium ore's leaching rate and changes in its composition before and after leaching. Column leaching tests use a fixed leaching agent type and concentration over a longer leaching time to examine the uranium ore's leaching rate, liquid-to-solid ratio, and changes in its composition before and after leaching. The advantage of using loose uranium ore samples for leaching tests is that suitable leaching test conditions can be screened to examine the leaching rate of uranium ore and the changes in material composition before and after leaching. However, the disadvantage is that the original physical structure of the uranium ore sample is destroyed, and it is impossible to know the changes in the material structure of the sample during the leaching process. In addition, the leaching performance of loose samples cannot represent the leaching performance in uranium ore formations.

[0004] Currently, some experiments use plug-shaped core samples for permeability testing, which can quickly grasp the permeability of the core. However, the disadvantage is that the solution passage time is short, only the changes in the seepage conditions are considered, and the leaching process of the core is not examined. As a result, it is impossible to know the changes in parameters such as the material composition of the uranium ore, the uranium concentration of the leachate, the impurity ion content and the leaching rate. Summary of the Invention

[0005] The purpose of the present invention is to provide a sandstone-type uranium ore plug-shaped core in situ leaching test method and system, which can not only realize the in situ leaching of sandstone-type uranium ore plug-shaped cores, simulate the in situ uranium leaching process in the actual ore layer, but also meet the permeability test requirements of the plug-shaped cores during the leaching process.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] An in-situ leaching test method for a sandstone-type uranium ore plug-shaped core, the method comprising:

[0008] obtaining a uranium ore core, and using the uranium ore core to prepare a plug-shaped core, a block core, and a powdered core;

[0009] Performing a CT scan test on the plug-shaped core to obtain first parameters before leaching; the first parameters include: connected pore parameters, throat radius, and mineral particle size parameters; the connected pore parameters include the size, number, and distribution of connected pores; and the mineral particle size parameters include the size and distribution of mineral particle sizes;

[0010] Performing process mineralogy analysis on the block core to obtain a second parameter before leaching; the second parameter includes: uranium mineral content and clay mineral content;

[0011] The powdered core is subjected to a complete chemical analysis test to obtain the content of chemical elements before leaching; the chemical elements include: uranium, U 4+ 、U 6+ 、Ca、Mg、Al、Fe、Fe 2+ 、Fe 3+ , C and S;

[0012] Determining pore parameters of the plug-shaped core before leaching; the pore parameters include pore volume and porosity;

[0013] Using a preset leaching method, an in-situ leaching test is performed on the plunger-shaped core to draw a permeability change curve;

[0014] Determining a first parameter after leaching, a second parameter after leaching, and a content of chemical elements after leaching based on the plug-shaped core after the in-situ leaching test;

[0015] determining pore parameters of the plug-shaped core after leaching;

[0016] Determining whether the preset leaching method meets the preset leaching requirements based on the permeability change curve, the pore parameters before leaching, and the pore parameters after leaching;

[0017] According to the first parameter before leaching, the second parameter before leaching, the content of the chemical element before leaching, the first parameter after leaching, the second parameter after leaching, and the content of the chemical element after leaching, the changes in the first parameter, the second parameter, and the content of the chemical element when the in-situ leaching test is performed on the plug-shaped core using the preset leaching method are determined.

[0018] Optionally, determining the pore parameters of the plug-shaped core before leaching specifically includes:

[0019] Determining the structural parameters of the plunger-shaped core before leaching; the structural parameters include: length, diameter, and particle skeleton volume;

[0020] The pore parameters of the plug-shaped core before leaching are determined according to the structural parameters of the plug-shaped core before leaching.

[0021] Optionally, determining the pore parameters of the plug-shaped core after leaching specifically includes:

[0022] determining structural parameters of the plunger core after leaching;

[0023] The pore parameters of the plug-shaped core after leaching are determined based on the structural parameters of the plug-shaped core after leaching.

[0024] Optionally, determining the first parameter after leaching, the second parameter after leaching, and the content of chemical elements after leaching based on the plug-shaped core after the in-situ leaching test specifically includes:

[0025] Perform CT scanning on the plug-shaped core after the in-situ leaching test to obtain the first parameters after leaching;

[0026] Using the plug-shaped core after the in-situ leaching test, leached block core and leached powder core are prepared;

[0027] Conduct process mineralogy analysis and testing on the leached block core to obtain the second parameter after leaching;

[0028] The powdered core after leaching is subjected to a complete chemical analysis test to obtain the content of chemical elements after leaching.

[0029] A sandstone-type uranium ore plug-shaped core in-situ leaching test system, the system comprising:

[0030] A core acquisition module, used to obtain uranium ore cores and use the uranium ore cores to prepare plug-shaped cores, block cores and powdered cores;

[0031] a module for determining first parameters before leaching, configured to perform a CT scan test on the plunger core to obtain first parameters before leaching; the first parameters include: connected pore parameters, throat radius, and mineral particle size parameters; the connected pore parameters include the size, number, and distribution of connected pores; and the mineral particle size parameters include the size and distribution of mineral particle sizes;

[0032] a module for determining a second parameter before leaching, configured to perform a process mineralogy analysis on the block core to obtain a second parameter before leaching; the second parameter includes: a content of uranium minerals and a content of clay minerals;

[0033] The element content determination module before leaching is used to perform a full chemical analysis test on the powdered core to obtain the content of chemical elements before leaching; the chemical elements include: uranium, U 4+ 、U 6+ 、Ca、Mg、Al、Fe、Fe 2+ 、Fe 3+ , C and S;

[0034] a pore parameter determination module before leaching, used to determine the pore parameters of the plunger-shaped core before leaching; the pore parameters include pore volume and porosity;

[0035] a leaching module, configured to conduct an in-situ leaching test on the plunger-shaped core using a preset leaching method and draw a permeability change curve;

[0036] a post-leaching parameter determination module, for determining a first parameter after leaching, a second parameter after leaching, and the content of chemical elements after leaching based on the plug-shaped core after the in-situ leaching test;

[0037] a post-leaching pore parameter determination module, configured to determine the pore parameters of the plunger core after leaching;

[0038] a judgment module, configured to judge whether the preset leaching method meets the preset leaching requirements based on the permeability change curve, the pore parameters before leaching, and the pore parameters after leaching;

[0039] The comparison module is used to determine, based on the first parameter before leaching, the second parameter before leaching, the content of the chemical element before leaching, the first parameter after leaching, the second parameter after leaching, and the content of the chemical element after leaching, how the first parameter, the second parameter, and the content of the chemical element change when the plunger-shaped core is subjected to an in-situ leaching test using the preset leaching method.

[0040] Optionally, the pre-leaching pore parameter determination module specifically includes:

[0041] a pre-leaching structural parameter determination unit, configured to determine the structural parameters of the plunger-shaped core before leaching; the structural parameters comprising: length, diameter, and particle skeleton volume;

[0042] The pre-leaching pore parameter determination unit is used to determine the pre-leaching pore parameters of the plug-shaped core according to the pre-leaching structural parameters of the plug-shaped core.

[0043] Optionally, the post-leaching pore parameter determination module specifically includes:

[0044] a post-leaching structural parameter determination unit, configured to determine the structural parameters of the plunger-shaped core after leaching;

[0045] The post-leaching pore parameter determination unit is used to determine the post-leaching pore parameters of the plug-shaped core according to the post-leaching structural parameters of the plug-shaped core.

[0046] Optionally, the post-leaching parameter determination module specifically includes:

[0047] a first parameter determination unit after leaching, configured to perform a CT scan test on the plug-shaped core after the in-situ leaching test to obtain the first parameter after leaching;

[0048] A core preparation unit is used to prepare leached block core and leached powder core using the plug-shaped core after the in-situ leaching test;

[0049] A post-leaching second parameter determination unit is used to perform process mineralogy analysis on the block core after leaching to obtain the post-leaching second parameter;

[0050] The element content determination unit after leaching is used to perform a full chemical analysis test on the powdered core after leaching to obtain the content of chemical elements after leaching.

[0051] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0052] The invention discloses an in-situ leaching test method and system for a sandstone-type uranium ore plug-shaped core. The method comprises: obtaining a uranium ore core, and using the uranium ore core to prepare a plug-shaped core, a block core, and a powder core; performing a CT scanning test on the plug-shaped core to obtain a first parameter before leaching; the first parameter comprises a connected pore parameter, a throat radius, and a mineral particle size parameter; the connected pore parameter comprises the size, number, and distribution of the connected pores; the mineral particle size parameter comprises the size and distribution of the mineral particle size; performing a process mineralogy analysis test on the block core to obtain a second parameter before leaching; the second parameter comprises the content of uranium minerals and the content of clay minerals; performing a full chemical analysis test on the powder core to obtain the content of chemical elements before leaching; the chemical elements comprise: uranium, U 4+ 、U 6+ 、Ca、Mg、Al、Fe、Fe 2+ 、Fe 3+, C and S; determine the pore parameters of the plug-shaped core before leaching; the pore parameters include pore volume and porosity; use a preset leaching method to conduct an in situ leaching test on the plug-shaped core and draw a permeability change curve; determine the first parameter after leaching, the second parameter after leaching and the content of chemical elements after leaching based on the plug-shaped core after the in situ leaching test; determine the pore parameters of the plug-shaped core after leaching; judge whether the preset leaching method meets the preset leaching requirements based on the permeability change curve, the pore parameters before leaching and the pore parameters after leaching; determine the changes in the first parameter, the second parameter and the content of chemical elements when the in situ leaching test is conducted on the plug-shaped core using the preset leaching method based on the first parameter before leaching, the second parameter before leaching, the content of chemical elements before leaching, the first parameter after leaching, the second parameter after leaching and the content of chemical elements after leaching. The present invention can not only realize in-situ leaching of plug-shaped cores of sandstone-type uranium ore and simulate the in-situ leaching process of uranium in actual ore layers, but also meet the permeability test requirements of the plug-shaped cores during the leaching process. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, 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 any creative work.

[0054] Figure 1 A schematic flow chart of an in-situ leaching test method for a sandstone-type uranium ore plug core provided by an embodiment of the present invention;

[0055] Figure 2 Schematic diagram of the structure of the in-situ leaching test system for sandstone-type uranium ore plug-shaped cores provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0057] The purpose of the present invention is to provide a sandstone-type uranium ore plug-shaped core in situ leaching test method and system, aiming to realize in situ leaching of sandstone-type uranium ore plug-shaped cores, simulate the in situ uranium leaching process in the actual ore layer, and meet the permeability test requirements of the plug-shaped cores during the leaching process.

[0058] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0059] Figure 1 Schematic diagram of the in-situ leaching test method for sandstone-type uranium ore plug core provided in Example 1 of the present invention. Figure 1 As shown, the in-situ leaching test method of the sandstone-type uranium ore plug core in this embodiment includes:

[0060] Step 101: Obtain uranium ore cores, and use the uranium ore cores to prepare plug-shaped cores, block-shaped cores, and powdered cores.

[0061] Step 102: Perform a CT scan test on the plug-shaped core to obtain first parameters before leaching. The first parameters include: connected pore parameters, throat radius, and mineral particle size parameters. The connected pore parameters include the size, number, and distribution of connected pores, and the mineral particle size parameters include the size and distribution of mineral particle sizes.

[0062] Step 103: Performing process mineralogical analysis on the block core to obtain the second parameter before leaching; the second parameter includes: the content of uranium minerals and the content of clay minerals.

[0063] Step 104: Perform a complete chemical analysis on the powdered core to obtain the content of chemical elements before leaching; the chemical elements include: uranium, U 4+ 、U 6+ 、Ca、Mg、Al、Fe、Fe 2+ 、Fe 3+ , C and S.

[0064] Step 105: Determine the pore parameters of the plug-shaped core before leaching; the pore parameters include pore volume and porosity.

[0065] Step 106: Using a preset leaching method, perform an in-situ leaching test on the plug-shaped core and draw a permeability change curve.

[0066] Step 107: Determine the first parameter after leaching, the second parameter after leaching, and the content of chemical elements after leaching based on the plug-shaped core after the in-situ leaching test.

[0067] Step 108: Determine the pore parameters of the plug-shaped core after leaching.

[0068] Step 109: judging whether the preset leaching method meets the preset leaching requirements based on the permeability change curve, the pore parameters before leaching, and the pore parameters after leaching.

[0069] Step 110: Determine changes in the first parameter, the second parameter, and the content of the chemical element when an in-situ leaching test is performed on the plug-shaped core using a preset leaching method based on the first parameter before leaching, the second parameter before leaching, the content of the chemical element before leaching, the first parameter after leaching, the second parameter after leaching, and the content of the chemical element after leaching.

[0070] As an optional embodiment, determining the pore parameters of the plug-shaped core before leaching specifically includes:

[0071] Determine the structural parameters of the plug-shaped core before leaching; structural parameters include: length, diameter and particle skeleton volume.

[0072] The pore parameters of the plug-shaped core before leaching were determined based on the structural parameters of the plug-shaped core before leaching.

[0073] As an optional embodiment, determining the pore parameters of the plug-shaped core after leaching specifically includes:

[0074] Determine the structural parameters of the plug-shaped core after leaching.

[0075] The pore parameters of the plug-shaped core after leaching are determined based on the structural parameters of the plug-shaped core after leaching.

[0076] As an optional implementation, step 107 specifically includes:

[0077] The plug-shaped cores after the in-situ leaching test were subjected to CT scanning test to obtain the first parameters after leaching.

[0078] Leached block cores and leached powder cores were prepared using the plug cores after the in-situ leaching test.

[0079] The process mineralogy analysis test is carried out on the block core after leaching to obtain the second parameter after leaching.

[0080] The powdered core after leaching is subjected to a complete chemical analysis test to obtain the content of chemical elements after leaching.

[0081] Specifically, the technical solution of the present invention can be divided into four stages: pre-leaching treatment, in-situ leaching test, post-leaching treatment and in-situ leaching comprehensive evaluation.

[0082] 1. Pre-leaching treatment

[0083] (1) Obtain uranium ore cores and divide them into two parts: plug cores and loose cores (loose cores include block cores and powder cores). The plug cores and loose cores must come from the same piece of uranium ore, so that the test data before and after leaching are meaningful for comparison.

[0084] (2) Loose cores are used for mineralogical and chemical analysis of uranium ore. This analysis is completed before the leaching test to obtain the initial mineralogical and chemical composition of the uranium ore.

[0085] (3) Before the leaching test, the in-situ CT scanning analysis of the plunger core was completed to obtain a three-dimensional digital core and obtain the initial pore structure characteristics, mineral particle size characteristics and other parameters of the core.

[0086] More specifically, pre-leaching treatment includes:

[0087] 1.1 Obtaining uranium ore cores: Obtain uranium ore cores through drilling projects, conduct core cataloging, and select appropriate cores for testing based on the uranium content in the ore.

[0088] 1.2 Prepare a plug-shaped core: Select a complete, undamaged, and crack-free uranium ore core and use a core drill to produce a plug-shaped core. Typical plug-shaped core diameters include 10 mm, 25 mm, 38 mm, 50 mm, and 70 mm. The length-to-diameter ratio of the plug-shaped core should be greater than 1. Measure the plug-shaped core's length L, diameter d, and mass m1.

[0089] 1.3 Preparation of process mineralogical analysis test samples: After the preparation of the plunger core is completed, the remaining uranium ore core is collected and the relatively complete block core is prepared into corresponding sample specifications according to the different requirements of process mineralogical analysis test for process mineralogical analysis test.

[0090] 1.4 Preparation of chemical analysis test samples: After the preparation process of the mineralogical analysis test samples is completed, the remaining cores are crushed and ground to 200 mesh to prepare powdered samples (i.e., powdered cores) for chemical analysis test.

[0091] 1.5 Process Mineralogical Analysis and Testing: Based on the block cores, electron microscopy, electron probe, scanning electron microscopy and plasma mass spectrometry were carried out to analyze the mineral composition, major element composition, trace element content and uranium occurrence of the cores. The characteristic mineral composition and geochemical characteristics of uranium minerals, clay minerals, gangue minerals, etc. that affect leaching were identified. The content of uranium minerals, clay minerals and other minerals was obtained, and these contents were used for the subsequent calculation of leaching rates.

[0092] 1.6 Chemical analysis test: Based on the powdered core, a chemical analysis test was carried out to obtain U (uranium), U 4+ / U 6+ 、Ca、Mg、Al、Fe、Fe 2+ / Fe 3+The content of key chemical elements such as C and S provides basic data for chemical reactions in the uranium leaching process. The total uranium metal content in the core is calculated based on the uranium grade of the original ore and the core mass.

[0093] M 总 =m1×C1.

[0094] Among them, M 总 is the total uranium metal content in the core, in g; m1 is the initial core mass, in g; C1 is the uranium content in the original ore where the core is located, in %.

[0095] 1.7 Pre-leaching CT Scan Test: A pre-leaching CT scan test was performed on the plunger core to obtain a three-dimensional digital core. The CT scan grayscale image was thresholded and the core pore radius distribution map was processed using the maximum sphere algorithm to obtain parameters such as connected pores, throat radius, and mineral particle size. This accurately characterizes the initial pore structure and mineral particle size characteristics of the uranium ore. The size, number, and distribution of connected pores and the size of the throat radius can explain the ore's pore structure characteristics, while the size and distribution of mineral particle size can explain the mineral particle size characteristics.

[0096] 2. In situ leaching test

[0097] The plug-shaped core is used for in-situ leaching test. Before the test begins, the appropriate leaching agent is selected and prepared according to the mineralogical and chemical composition of the uranium ore. During the in-situ leaching test, the permeability changes of the core are tracked in a timely manner to evaluate the effect of the leaching agent on the permeability of the core; and the leachate is collected for relevant analysis and testing to obtain the pH, uranium concentration, and Ca, Mg, Fe, Al, SO4 2- and Cl - Based on these parameters, the liquid meter leaching rate of the core, as well as the uranium concentration and impurity ion concentration change curve can be calculated to evaluate the leaching performance of uranium ore.

[0098] More specifically, in situ leaching tests include:

[0099] Leaching tests and seepage tests under different conditions were carried out using an in-situ leaching test device for sandstone-type uranium deposits.

[0100] 2.1 Porosity test: Use an automatic porosity meter to obtain the particle skeleton volume of the plunger core (this is the skeleton volume before leaching, i.e. Vs). Based on the length and diameter of the core, the pore volume and porosity of the core are calculated. The calculation formulas for pore volume and porosity are as follows:

[0101] Vb=L×π(1 / 2d) 2 .

[0102]

[0103] Where Vb is the total volume of the core, in cm 3 ; L is the length of the core, in cm; d is the diameter of the core, in cm; P is the porosity of the core, in %; Vp is the pore volume of the core, in cm 3 ; Vs is the particle skeleton volume of the core, in cm 3 Vb, P, and Vp are unknown quantities, while Vs, L, and d are known quantities. Vs is obtained from the porosity automatic determination instrument, and L and d are measured in step 1.2.

[0104] 2.2 Gas Permeability Testing: Gas permeability testing of plunger cores (pre-leaching cores) is performed using an automated permeability meter. This method offers the advantages of rapid testing and non-destructive testing. Because in-situ leaching tests involve passing liquid through the core, which has a much greater density and viscosity than gas, and the test cycle is long and the physical-chemical reactions are complex, gas permeability testing can be used to quickly assess the core's permeability, providing a foundation for permeability evaluation in in-situ leaching tests.

[0105] 2.3 Place the plunger core in the in-situ leaching core holder. By matching plunger cores of different diameters with in-situ leaching core holders of different diameters, different test conditions and test objectives such as different leaching intensities and seepage rates can be achieved.

[0106] 2.4 Fill the intermediate container with the prepared leaching agent solution. There are two ways to prepare the leaching agent: ① In the first method, when acid or alkaline leaching is used, a certain type and concentration of acid or alkali is mixed with formation water to obtain a leaching agent solution, which can be directly injected into the intermediate container. ② In the second method, when neutral leaching is used, the intermediate container needs to be connected to a gas-liquid mixing container, which needs to be connected to a CO2 gas cylinder and an O2 gas cylinder. The CO2 and O2 are thoroughly mixed with the formation water under a certain pressure, and the mixed solution is injected into the intermediate container under the same pressure to maintain the pressure.

[0107] 2.5 Surrounding rock pressure application method: A constant pressure and constant flow pump injects distilled water into the annulus of the in-situ leaching core holder through the annular pressure pipeline. The annular pressure is monitored and maintained at the required pressure. This pressure is determined based on the core's burial depth in the formation and the test purpose.

[0108] 2.6 Inlet Pressure Application Method: ① Set the parameters of a constant pressure and constant flow pump to inject the leachate solution from intermediate container X into the in-situ leaching core holder's inlet pipeline at a specific flow rate, and monitor the inlet pressure. The intermediate container maintains a constant pressure throughout the leachate solution injection process. ② Two intermediate containers are used. When the solution in one intermediate container X is depleted, the other intermediate container Y is automatically switched to the next container. This cycle is repeated throughout the test to ensure continuous injection of the leachate solution into the core and the continuity of the leaching process.

[0109] 2.7 After the leachate solution flows out of the outlet pipe of the in-situ leaching core holder, a certain back pressure can be set and monitored.

[0110] 2.8 The leachate (the leachate after passing through the core) flows into the automatic seepage calculation system. After the flow rate stabilizes, the permeability change data of the core during the leaching process is calculated and a permeability change curve, i.e., a time-permeability curve, is drawn.

[0111]

[0112] Among them, K is the permeability of the core, in mD; Q is the flow rate of liquid through the core per unit time, in cm 3 / s; μ is the viscosity of the liquid, which is the same before and after flowing through the core, and the unit is Pa·s; L is the length of the core, and the unit is cm; ΔP is the pressure difference before and after the liquid passes through the core, and the unit is MPa; A is the cross-sectional area of ​​the liquid passing through the core, and the unit is cm 2 .

[0113] 2.9 According to the test objectives and the flow rate changes during the leaching process, determine the frequency of collecting the leachate, record the volume of the leachate, and use equipment such as pH meter, potentiometer, conductivity meter, etc. to monitor parameters such as potential and conductivity in real time.

[0114] 2.10 Conduct chemical analysis and testing on the uranium concentration and impurity ion concentration of the leachate, calculate the liquid meter leached uranium metal amount, liquid meter leaching rate, and impurity ion leaching of the core, and draw the change curve of uranium leaching rate, uranium concentration and impurity ion concentration.

[0115]

[0116] Among them, E 液计 is the liquid leaching rate of the core, in %; M 液计 is the amount of uranium metal leached out by liquid meter, in g; M 总 is the total uranium metal content in the core, in g; V is the volume of the leachate, in L; ρ u is the uranium concentration of the leachate, in g / L.

[0117] 3. Post-leaching treatment

[0118] (1) After the in-situ leaching test, the core was promptly subjected to in-situ CT scanning and analysis. The three-dimensional digital cores before and after leaching were compared to obtain the changes in the core pore structure and mineral particle size, which were used to evaluate the effect of the leaching agent on the material structure of the uranium ore.

[0119] (2) After the in-situ CT scanning analysis after leaching, the mineralogical analysis and chemical analysis of the leached core are carried out to obtain the mineral composition and chemical composition of the uranium ore after leaching. By comparing them with the initial mineral composition and chemical composition of the uranium ore, the slag leaching rate of the core can be calculated and the effect of the leaching agent on the mineral composition and chemical composition of the uranium ore can be evaluated.

[0120] More specifically, post-leaching treatment includes:

[0121] 3.1 CT scanning test after leaching: CT scanning test was performed on the plug-shaped core after leaching to obtain the three-dimensional digital core after leaching. The porosity, pore structure characteristics and mineral particle size characteristics of the core after leaching were analyzed and compared with the state before leaching.

[0122] 3.2 Process mineralogical analysis and test after leaching: After completing the post-leaching CT scan test, first cut a part of the plunger-shaped core after leaching to prepare a process mineralogical analysis test sample with the same specifications as the sample in step 1.3. Then, carry out process mineralogical analysis and test, using the same analysis method as step 1.3 before leaching, and compare before and after to obtain the changes in the mineral composition, major element composition, trace element content and uranium occurrence state of the core before and after leaching.

[0123] 3.3 Full chemical analysis test after leaching: After completing the process mineralogical analysis test after leaching, the remaining post-leaching core samples are crushed and ground to 200 mesh to prepare powder samples, the same as the method in step 1.4. Then, a full chemical analysis test is carried out, using the same analysis method as step 1.4 before leaching, and a before-and-after comparison is performed to obtain the changes in the key chemical element content of the core before and after leaching, and the slag-based leached uranium metal content and slag-based leaching rate are calculated based on the uranium metal content of the core before and after leaching.

[0124]

[0125] Among them, E 渣计 is the slag leaching rate of the core, in %; M 渣计 is the amount of uranium metal leached from the slag, in g; M 总is the total uranium metal content in the core, in g; m2 is the core mass after leaching, in g; C2 is the uranium grade of the core after leaching, in %; m1 is the initial core mass, in g; C1 is the uranium content in the original ore where the core is located, in %.

[0126] 4. Comprehensive evaluation of in-situ leaching

[0127] The permeability and leaching properties were comprehensively evaluated by comparing the mineral composition, chemical composition, pore structure, and leachate analysis of uranium ore before and after leaching.

[0128] More specifically, the comprehensive in situ leaching evaluation includes:

[0129] A comprehensive in situ leaching evaluation method for sandstone-type uranium ore cores was developed based on comparative analysis of process mineralogy, chemical elements, and CT scan tests before and after leaching, as well as real-time tracking and analysis of the leachate during the leaching process. This method compares the changes in pore structure and permeability of the cores before and after leaching, comprehensively evaluating the core's permeability. (During the in situ leaching test, the changes in the core permeability curve indicate whether the leaching process increased or decreased the core's permeability, thereby determining the suitability of the selected leaching method.) Comparative analysis of changes in the core's mineralogy and chemical composition before and after leaching, as well as changes in the leachate's chemical composition, comprehensively evaluates the core's leaching performance. (During the in situ leaching test, the changes in the uranium leaching rate, uranium concentration, and impurity ion concentration curves indicate the impact of the leaching process on the uranium leaching rate, uranium concentration, and impurity ion concentration, thereby determining the suitability of the selected leaching method.) This method maximizes the reproduction of the uranium ore's original seepage and leaching conditions in the stratum, providing reliable parameter guidance for practical production in in situ uranium mines.

[0130] The beneficial effects of the present invention are:

[0131] 1. Without destroying the original structure of the uranium ore sample, the core leaching rate, uranium concentration, impurity ion concentration and other parameter changes can be obtained in situ. In addition, the core permeability changes can be observed in real time during leaching, simulating the actual in-situ uranium leaching process in the ore layer to the greatest extent possible, which is more in line with the idea of ​​in-situ uranium leaching.

[0132] 2. Previous leaching test methods were unable to compare before and after leaching. The present invention can compare and analyze samples before and after leaching, solving the problem of being unable to know the underground leaching process during in-situ uranium leaching.

[0133] 3. In the past, leaching tests and seepage tests were conducted independently, and there was no correlation between the leaching data and the seepage data. The present invention can combine the respective advantages of leaching tests and seepage tests, simultaneously obtain leaching performance and permeability, and analyze the correlation between the two parameters. This is also the analysis of the impact of seepage changes on leaching effect that needs to be solved in the in-situ uranium leaching process.

[0134] Figure 2 Schematic diagram of the structure of the sandstone-type uranium ore plug-shaped core in-situ leaching test system provided by the embodiment of the present invention. Figure 2 As shown, the sandstone-type uranium ore plug-shaped core in-situ leaching test system in this embodiment includes:

[0135] The core acquisition module 201 is used to obtain uranium ore cores and use the uranium ore cores to prepare plug-shaped cores, block cores and powdered cores.

[0136] The module 202 for determining the first parameters before leaching is used to perform a CT scan test on the plunger core to obtain the first parameters before leaching. The first parameters include: connected pore parameters, throat radius, and mineral particle size parameters. The connected pore parameters include the size, number, and distribution of the connected pores, and the mineral particle size parameters include the size and distribution of the mineral particle size.

[0137] The second parameter determination module 203 before leaching is used to perform process mineralogical analysis on the block core to obtain the second parameter before leaching; the second parameter includes: the content of uranium minerals and the content of clay minerals.

[0138] The element content determination module 204 before leaching is used to perform a full chemical analysis test on the powdered core to obtain the content of chemical elements before leaching; the chemical elements include: uranium, U 4+ 、U 6+ 、Ca、Mg、Al、Fe、Fe 2+ 、Fe 3+ , C and S.

[0139] The pre-leaching pore parameter determination module 205 is used to determine the pore parameters of the plug-shaped core before leaching; the pore parameters include pore volume and porosity.

[0140] The leaching module 206 is used to perform an in-situ leaching test on the plug-shaped core using a preset leaching method and draw a permeability change curve.

[0141] The post-leaching parameter determination module 207 is used to determine the first parameter after leaching, the second parameter after leaching and the content of chemical elements after leaching based on the plug-shaped core after the in-situ leaching test.

[0142] The post-leaching pore parameter determination module 208 is used to determine the pore parameters of the plug-shaped core after leaching.

[0143] The judgment module 209 is used to judge whether the preset leaching method meets the preset leaching requirements according to the permeability change curve, the pore parameters before leaching, and the pore parameters after leaching.

[0144] The comparison module 210 is used to determine changes in the first parameter, the second parameter, and the content of the chemical element when an in-situ leaching test is performed on the plug-shaped core using a preset leaching method based on the first parameter before leaching, the second parameter before leaching, the content of the chemical element before leaching, the first parameter after leaching, the second parameter after leaching, and the content of the chemical element after leaching.

[0145] As an optional embodiment, the pre-leaching pore parameter determination module 205 specifically includes:

[0146] The pre-leaching structural parameter determination unit is used to determine the structural parameters of the plug-shaped core before leaching; the structural parameters include: length, diameter and particle skeleton volume.

[0147] The pore parameter determination unit before leaching is used to determine the pore parameters of the plug-shaped core before leaching according to the structural parameters of the plug-shaped core before leaching.

[0148] As an optional embodiment, the post-leaching pore parameter determination module 208 specifically includes:

[0149] The post-leaching structural parameter determination unit is used to determine the structural parameters of the plug-shaped core after leaching.

[0150] The post-leaching pore parameter determination unit is used to determine the post-leaching pore parameters of the plug-shaped core according to the post-leaching structural parameters of the plug-shaped core.

[0151] As an optional embodiment, the post-leaching parameter determination module 207 specifically includes:

[0152] The first parameter determination unit after leaching is used to perform a CT scanning test on the plunger-shaped core after the in-situ leaching test to obtain the first parameter after leaching.

[0153] The core preparation unit is used to prepare leached block core and leached powder core using the plug-shaped core after the in-situ leaching test.

[0154] The post-leaching second parameter determination unit is used to perform process mineralogy analysis and testing on the block core after leaching to obtain the post-leaching second parameter.

[0155] The element content determination unit after leaching is used to perform a full chemical analysis test on the powdered core after leaching to obtain the content of chemical elements after leaching.

[0156] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0157] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A sandstone-type uranium ore plug-shaped core in-situ leaching test method, characterized in that: The method comprises: obtaining a uranium ore core, and using the uranium ore core to prepare a plug-shaped core, a block core, and a powdered core; Performing a CT scan test on the plug-shaped core to obtain first parameters before leaching; the first parameters include: connected pore parameters, throat radius, and mineral particle size parameters; the connected pore parameters include the size, number, and distribution of connected pores; and the mineral particle size parameters include the size and distribution of mineral particle sizes; Performing process mineralogy analysis on the block core to obtain a second parameter before leaching; the second parameter includes: uranium mineral content and clay mineral content; The powdered core is subjected to a complete chemical analysis test to obtain the content of chemical elements before leaching; the chemical elements include: uranium, U 4+ 、U 6+ 、Ca、Mg、Al、Fe、Fe 2+ 、Fe 3+ , C and S; Determining pore parameters of the plug-shaped core before leaching; the pore parameters include pore volume and porosity; Using a preset leaching method, an in-situ leaching test is performed on the plunger-shaped core to draw a permeability change curve; Determining a first parameter after leaching, a second parameter after leaching, and a content of chemical elements after leaching based on the plug-shaped core after the in-situ leaching test; determining pore parameters of the plug-shaped core after leaching; Determining whether the preset leaching method meets the preset leaching requirements based on the permeability change curve, the pore parameters before leaching, and the pore parameters after leaching; Determining, based on the first parameter before leaching, the second parameter before leaching, the content of the chemical element before leaching, the first parameter after leaching, the second parameter after leaching, and the content of the chemical element after leaching, how the first parameter, the second parameter, and the content of the chemical element change when an in-situ leaching test is performed on the plug-shaped core using the preset leaching method; The first parameter after leaching, the second parameter after leaching and the content of chemical elements after leaching are determined based on the plug-shaped core after the in-situ leaching test, specifically including: Perform CT scanning on the plug-shaped core after the in-situ leaching test to obtain the first parameters after leaching; Using the plug-shaped core after the in-situ leaching test, leached block core and leached powder core are prepared; Conduct process mineralogy analysis and testing on the leached block core to obtain the second parameter after leaching; The powdered core after leaching is subjected to a complete chemical analysis test to obtain the content of chemical elements after leaching.

2. The in-situ leaching test method for sandstone-type uranium ore plug core according to claim 1, characterized in that: Determining the pore parameters of the plug-shaped core before leaching specifically includes: Determining the structural parameters of the plunger-shaped core before leaching; the structural parameters include: length, diameter, and particle skeleton volume; The pore parameters of the plug-shaped core before leaching are determined according to the structural parameters of the plug-shaped core before leaching.

3. The in-situ leaching test method for sandstone-type uranium ore plug core according to claim 2, characterized in that: The determining of the pore parameters of the plug-shaped core after leaching specifically includes: determining structural parameters of the plunger core after leaching; The pore parameters of the plug-shaped core after leaching are determined based on the structural parameters of the plug-shaped core after leaching.

4. A sandstone-type uranium ore plug-shaped core in-situ leaching test system, characterized in that: The system comprises: A core acquisition module, used to obtain uranium ore cores and use the uranium ore cores to prepare plug-shaped cores, block cores and powdered cores; a module for determining first parameters before leaching, configured to perform a CT scan test on the plunger core to obtain first parameters before leaching; the first parameters include: connected pore parameters, throat radius, and mineral particle size parameters; the connected pore parameters include the size, number, and distribution of connected pores; and the mineral particle size parameters include the size and distribution of mineral particle sizes; a module for determining a second parameter before leaching, configured to perform a process mineralogy analysis on the block core to obtain a second parameter before leaching; the second parameter includes: a content of uranium minerals and a content of clay minerals; The element content determination module before leaching is used to perform a full chemical analysis test on the powdered core to obtain the content of chemical elements before leaching; the chemical elements include: uranium, U 4+ 、U 6+ 、Ca、Mg、Al、Fe、Fe 2+ 、Fe 3+ , C and S; a pore parameter determination module before leaching, used to determine the pore parameters of the plunger-shaped core before leaching; the pore parameters include pore volume and porosity; a leaching module, configured to conduct an in-situ leaching test on the plunger-shaped core using a preset leaching method and draw a permeability change curve; a post-leaching parameter determination module, for determining a first parameter after leaching, a second parameter after leaching, and the content of chemical elements after leaching based on the plug-shaped core after the in-situ leaching test; a post-leaching pore parameter determination module, configured to determine the pore parameters of the plunger core after leaching; a judgment module, configured to judge whether the preset leaching method meets the preset leaching requirements based on the permeability change curve, the pore parameters before leaching, and the pore parameters after leaching; a comparison module for determining, based on the first parameter before leaching, the second parameter before leaching, the content of the chemical element before leaching, the first parameter after leaching, the second parameter after leaching, and the content of the chemical element after leaching, changes in the first parameter, the second parameter, and the content of the chemical element when the plunger core is subjected to an in-situ leaching test using the preset leaching method; Among them, the post-leaching parameter determination module specifically includes: a first parameter determination unit after leaching, configured to perform a CT scan test on the plug-shaped core after the in-situ leaching test to obtain the first parameter after leaching; A core preparation unit is used to prepare leached block core and leached powder core using the plug-shaped core after the in-situ leaching test; A post-leaching second parameter determination unit is used to perform process mineralogy analysis on the block core after leaching to obtain the post-leaching second parameter; The element content determination unit after leaching is used to perform a full chemical analysis test on the powdered core after leaching to obtain the content of chemical elements after leaching.

5. The sandstone-type uranium ore plug-shaped core in-situ leaching test system according to claim 4, characterized in that: The pre-leaching pore parameter determination module specifically includes: a pre-leaching structural parameter determination unit, configured to determine the structural parameters of the plunger-shaped core before leaching; the structural parameters comprising: length, diameter, and particle skeleton volume; The pre-leaching pore parameter determination unit is used to determine the pre-leaching pore parameters of the plug-shaped core according to the pre-leaching structural parameters of the plug-shaped core.

6. The sandstone-type uranium ore plug-shaped core in-situ leaching test system according to claim 5, characterized in that: The post-leaching pore parameter determination module specifically includes: a post-leaching structural parameter determination unit, configured to determine the structural parameters of the plunger-shaped core after leaching; The post-leaching pore parameter determination unit is used to determine the post-leaching pore parameters of the plug-shaped core according to the post-leaching structural parameters of the plug-shaped core.

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