An in-situ leaching method for large dip-angle sandstone-type uranium orebody

Abstract

A method for in-situ leaching of large dip angle sandstone-type uranium ore bodies. Step 1: Inject the leaching agent underground. Step 2: Design a well pattern suitable for in-situ leaching of large dip angle ore bodies. On the basis of a regular geometric square, arrange injection well A1 and pumping well 3 in the middle. Add injection well B2 along the strike direction of the ore body. Step 3: Install single-well filters into injection well 1 and pumping well 3. Step 4: Maintain the maximum injection volume of injection well 2. Step 5: Control the leaching agent injection parameters in Step 1.

Description

Technical Field

[0001] The present invention belongs to the method for extracting uranium resources, and particularly relates to a technical method for extracting large dip-angle uranium resources of in-situ leachable sandstone type in the field of uranium mining and metallurgy. Background Art

[0002] The in-situ leaching uranium extraction technology is the main extraction method for natural uranium production in China at present, and a third-generation natural uranium extraction technology system represented by the "CO2 + O2" in-situ leaching uranium extraction technology has been formed.

[0003] According to the theory of in-situ leaching uranium extraction technology, when using the in-situ leaching uranium extraction technology, it is generally required that the ore body shape is a horizontal layer or a gently inclined ore body with an inclination angle less than 10°, and the ore body has good horizontal continuity and a large transverse width. Under such conditions, it is convenient to arrange injection and production wells, so that the leaching agent can effectively flow in the ore layer position of the ore-bearing aquifer, which is conducive to achieving the injection-production balance and realizing the effective leaching of the ore body. The above goals can be achieved by using conventional in-situ leaching extraction technologies. For example, the well pattern arrangement of the well-site in-situ leaching process generally adopts regular geometric shapes such as regular hexagons and regular pentagons, etc., to achieve the injection-production balance during the leaching process.

[0004] For in-situ leachable sandstone-type ore bodies with a large dip angle (the ore body dip angle is generally greater than 20°), due to the large change in the occurrence space position of the ore body, there are still some key technical problems in how to realize the uniform flow of the leaching agent in the ore layer position of the ore-bearing aquifer, effectively leach the target ore layer to obtain a higher uranium concentration in the leaching solution, and reasonably control the balance of injection and production liquid volumes.

[0005] To solve the above problems, obtain a higher uranium concentration in the leaching solution (greater than 30 mg / L), realize the effective in-situ leaching and extraction of large dip-angle sandstone-type uranium resources, and further improve the recovery of uranium resources. Combining with actual mining experience, a technical method suitable for the in-situ leaching and mining of large dip-angle sandstone-type uranium ore bodies is specifically proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a technical method suitable for the in-situ leaching and mining of large dip-angle sandstone-type uranium ore bodies, and realize the effective leaching of large dip-angle sandstone-type uranium ore bodies by adopting technologies such as optimizing the well pattern arrangement of the well field, determining an economical and effective well spacing, and optimizing the single-well design.

[0007] The technical solution of the present invention is as follows: A method for in-situ leaching and mining of large dip-angle sandstone-type uranium ore bodies,

[0008] Step 1: Inject the leaching agent into the ground;

[0009] Step 2: Design a well pattern suitable for the in-situ leaching and mining of large dip-angle ore bodies; on the basis of a regular geometric square, arrange injection well A1, and arrange production well 3 in the middle; add injection well B2 along the strike direction of the ore body;

[0010] Step 3: Install the single-well filter into the injection well 1 and the pumping well 3;

[0011] Step 4: Maintain the maximum injection volume of the injection well 2;

[0012] Step 5: Control the leaching agent injection parameters in Step 1.

[0013] In the said Step 1, CO2 and O2 are used as the leaching agent; the leaching agent is injected underground.

[0014] Adjust the CO2 concentration to control the pH of the groundwater to be 6 - 8.

[0015] In the said Step 2, the injection well B2, the pumping well 3, and the injection well A1 are located at the same plane position.

[0016] In the said Step 2, the distance between the injection well A1 and the injection well B2 is 30m, the distance between the injection well B2 and the pumping well 3 is 30m, and the distance between the injection well A1 and the pumping well 3 is 42.4m.

[0017] In the said Step 2, the ratio of the sum of the number of the injection well A1 and the injection well B2 to the number of the controlled pumping well 3 is 2.6:1.

[0018] In the said Step 3, ensure that the included angle between the connection line between the single-well filters installed in the injection well 1 and the pumping well 3 respectively and the ore body strike is less than 5°.

[0019] In the said Step 4, maintain the maximum injection volume of the injection well 2 under the pressure of 1.6MPa.

[0020] In the said Step 4, adjust the injection volumes of the injection well 2 and the other surrounding injection wells to control the ratio of the injection volumes of the two to be 1.2 - 1.5.

[0021] In the said Step 5, control the oxygen concentration standard to be 450mg / L and the carbon dioxide injection concentration standard to be 100mg / L.

[0022] The remarkable effect of the present invention lies in: by designing a new well type layout, the problem of the extraction and injection balance in the in-situ leaching of steeply inclined ore bodies is solved. Through the reasonable design of the single-well filter and the effective adjustment of the leaching extraction and injection ratio and the leaching agent injection parameters, the uranium ore body is effectively leached, realizing the in-situ leaching of the steeply inclined sandstone-type uranium ore body. Brief Description of the Drawings

[0023] Figure 1 It is a schematic diagram suitable for the in-situ leaching of steeply inclined sandstone-type uranium ore bodies;

[0024] In the figure: injection well A1, injection well B2, pumping well 3 Detailed Embodiments

[0025] The following elaborates on the preferred embodiments of the present invention in conjunction with the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the scope of protection of the present invention more clearly defined.

[0026] The following further describes a method for in-situ leaching of large dip sandstone-type uranium ore bodies of the present invention in combination with a specific mining example of a large dip ore body in the Qianjiadian Qian II uranium deposit:

[0027] Step 1: According to the ore type of the large dip sandstone ore body in the Qianjiadian Qian II uranium deposit, use CO2 and O2 as leaching agents. Inject the leaching agent underground and adjust the CO2 concentration to control the pH of groundwater to be 6 - 8.

[0028] Step 2: Design a well pattern suitable for in-situ leaching of large dip ore bodies. On the basis of a regular geometric square, injection wells A1 are arranged around, and a pumping well 3 is arranged in the middle. Injection wells B2 are added along the strike direction of the ore body, and are located at the same plane position as the pumping well 3 and the injection wells A1.

[0029] Design the distance between injection well A1 and injection well B2 to be 30m, the distance between injection well B2 and pumping well 3 to be 30m, and the distance between injection well A1 and pumping well 3 to be 42.4m. Under the condition of the entire complete well pattern, the ratio of the sum of the numbers of injection wells A1 and injection wells B2 to the number of controlled pumping wells 3 is 2.6:1.

[0030] Step 3: Design method for the position of the single-well filter in the large dip ore body.

[0031] Install the single-well filter into injection well 1 and pumping well 3, and ensure that the connection line between the single-well filters installed in injection well 1 and pumping well 3 respectively forms an angle less than 5° with the strike of the ore body.

[0032] Step 4: Method for controlling the pumping and injection ratio. Keep the maximum injection volume of injection well 2 increasing along the strike of the ore body under a pressure of 1.6 MPa, and adjust the injection volumes of the other injection wells around injection well 2 to control the ratio of their injection volumes to be between 1.2 and 1.5.

[0033] Step 5: Control the leaching agent injection parameters in Step 1. Control the oxygen concentration standard to be 450 mg / L and the carbon dioxide injection concentration standard to be 100 mg / L. Appropriately adjust the injection parameters according to the leaching operation in the later stage.

[0034] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A method for in-situ leaching of large dip angle sandstone type uranium ore bodies, characterized in that: Step 1: Inject the leaching agent underground; Step 2: Design a well pattern suitable for in-situ leaching of large dip angle ore bodies; on the basis of a regular geometric square, arrange injection well A (1), and arrange a pumping well (3) in the middle; add injection well B (2) along the strike direction of the ore body; injection well B (2) is located at the same plane position as pumping well (3) and injection well A (1); the distance between injection well A (1) and injection well B (2) is 30m, the distance between injection well B (2) and pumping well (3) is 30m, and the distance between injection well A (1) and pumping well (3) is 42.4m; Step 3: Install single-well filters into injection well A (1) and pumping well (3); ensure that the included angle between the connection line between the single-well filters installed in injection well A (1) and pumping well (3) and the strike of the ore body is less than 5°; Step 4: Maintain the maximum injection volume of injection well B (2); Step 5: Control the leaching agent injection parameters in Step 1.

2. The in-situ leaching method for large dip angle sandstone-type uranium orebody according to claim 1, characterized in that: In the said Step 1, CO2 and O2 are used as leaching agents; the leaching agents are injected underground.

3. A method for in-situ leaching of large dip-angle sandstone-type uranium ore bodies according to claim 2, characterized in that: Adjust the CO2 concentration to control the pH of groundwater to be 6 - 8.

4. A method for in-situ leaching of large dip angle sandstone type uranium ore bodies according to claim 1, characterized in that: In the said Step 2, the ratio of the sum of the numbers of injection well A (1) and injection well B (2) to the number of controlled pumping well (3) is 2.6:

1.

5. A method for in-situ leaching of a large dip sandstone-type uranium orebody according to claim 1, characterized in that: In the said Step 4, maintain the maximum injection volume of injection well B (2) at a pressure of 1.6MPa.

6. A method for in-situ leaching of large dip angle sandstone-type uranium ore bodies according to claim 5, characterized in that: In the said Step 4, adjust the injection volumes of injection well B (2) and the other surrounding injection wells so that the ratio of the two injection volumes is controlled within 1.2 - 1.

5.

7. A method for in-situ leaching of large dip angle sandstone type uranium orebody according to claim 1, characterized in that: In the said Step 5, control the oxygen concentration standard to be 450mg / L, and the carbon dioxide injection concentration standard to be 100mg / L.

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