A chamber liquid collection process for ionic rare earth in-situ leaching

Abstract

The present invention discloses a chamber liquid collection process for in-situ leaching of ionic rare earths, which relates to the field of ionic rare earth mining technology. The process comprises: S1, excavating a liquid collection tunnel along the ridgeline at the foot of the ionic rare earth mine to the middle of the horizontal projection of the mountain; S2, supporting the liquid collection tunnel; S3, excavating a chamber at the middle of the horizontal projection of the mountain and at the end of the liquid collection tunnel, and supporting the chamber; S4, excavating a diversion element horizontally and upwardly around the chamber, excavating a vertical downward drainage trough at the opening of the diversion element to the chamber bottom, and excavating a liquid collection trench circumferentially around the chamber bottom and in the middle of the bottom of the liquid collection tunnel; S5, performing anti-seepage and anti-blocking treatment on the diversion element, drainage trough, liquid collection trench, chamber, and liquid collection tunnel. This chamber liquid collection process for in-situ leaching of ionic rare earths has low production costs and high leachate recovery rates.

Description

Technical Field

[0001] The present invention relates to the technical field of ionic rare earth mining, in particular to a liquid collection process for an ionic rare earth in-situ leaching chamber. Background Art

[0002] Ionic rare earth minerals are adsorbed on the surface of clay minerals in an ionic state. They have extensive industrial applications and are a critical strategic resource. The adsorbed rare earth ions in ionic rare earth ores can be exchanged for cations in an electrolyte solution. Currently, ionic rare earth ores are primarily mined using in-situ leaching (ISL). This process can be summarized as follows: injection holes are drilled on the mine surface and a leaching agent (ammonium sulfate or magnesium sulfate solution) is injected into the holes. The ammonium sulfate or magnesium sulfate solution migrates downward under the influence of hydraulic head, capillary forces, and gravity, and reacts with the adsorbed rare earth ions on the ore body to form a leachate. The exchanged rare earth ions migrate with the solution and, through a liquid collection system at the foot of the mountain, the solution ultimately converges into a collection tank. The rational design of the collection system is crucial to the recovery rate of ionic rare earth resources and the environmental friendliness of the ISL process.

[0003] Liquid collection projects generally include several methods, such as diversion holes, diversion holes combined with cut grooves, liquid collection tunnels, and liquid collection trenches. These methods are generally used in combination, and the combination varies depending on the geological conditions of the mine. For barefoot ionic rare earth mines (i.e., with bedrock exposed at the erosion base) with a good natural liquid collection base, a combination of diversion holes and liquid collection trenches can achieve good liquid collection results, with a liquid collection rate exceeding 80%. However, for ionic rare earth mines with complex geological conditions (for example, fully covered ionic rare earth mines with no bedrock exposed at the erosion base), the liquid collection effect of a combination of diversion holes and liquid collection trenches is less than ideal (with a liquid collection rate of only around 50%). Therefore, a combination of diversion holes, liquid collection trenches, and liquid collection tunnels is often used. This combination can increase the liquid collection rate to over 80%, but it requires the excavation of a diversion hole construction platform and large-scale mountain excavation, which not only increases production costs but also causes the loss of some rare earth resources. The large amount of soil piles generated also damages the ecological environment to a certain extent.

[0004] Ionic rare earth mines located under complex geological conditions account for a significant proportion (over 80%) of my country's ionic rare earth mines. Existing in-situ leaching processes, however, suffer from low leachate recovery rates and severe leakage, leading to the loss of rare earth resources and environmental pollution. While the Chinese patent "Artificial Floor Leaching Process with Comprehensive Interception Function (Patent No.: CN201711138165.5)" significantly improves leachate recovery, it places stringent requirements on equipment and proficiency, resulting in high construction costs and the continued presence of large-scale mountain excavation. To balance leachate recovery, environmental protection, and production costs, a new chamber leachate collection process for ionic rare earth in-situ leaching has been proposed. This process avoids large-scale excavation of ionic rare earth mines, achieving leachate recovery rates exceeding 90% and reducing leachate collection construction costs by over 50%. Summary of the Invention

[0005] The purpose of the present invention is to provide an ionic rare earth in-situ leaching chamber liquid collection process to solve the problems existing in the above-mentioned prior art, with low production cost and high leachate recovery rate.

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

[0007] The present invention provides a chamber liquid collection process for ionic rare earth in-situ leaching, comprising the following steps:

[0008] S1, at the foot of the ionic rare earth mine, a liquid collection tunnel is excavated along the ridge line to the middle of the horizontal projection of the mountain;

[0009] S2, supporting the liquid collecting roadway;

[0010] S3, excavating a chamber at the middle of the horizontal projection of the mountain and at the end of the liquid collection roadway, and supporting the liquid collection roadway and the chamber;

[0011] S4, excavating a diversion element horizontally and obliquely upward around the chamber, excavating a vertical downward drainage groove at the opening of the diversion element to the bottom of the chamber, and excavating a liquid collection groove around the bottom of the chamber and between the bottom of the liquid collection roadway;

[0012] S5, performing anti-seepage and anti-blocking treatment on the guide element, the drainage trough, the liquid collecting ditch, the chamber and the liquid collecting tunnel.

[0013] Preferably, in S2, the liquid collection tunnel and the chamber are both located in the semi-weathered layer below the ore body and above the bedrock, and the distance between the liquid collection tunnel and the chamber and the bottom surface of the ore body is not greater than 2m.

[0014] Preferably, in S2, the bottom surface of the liquid collecting tunnel and the bottom surface of the chamber maintain a slope of 3‰-7‰ with the horizontal plane.

[0015] Preferably, in S2, the cross-section of the liquid collection channel is trapezoidal, and the upper base of the liquid collection channel is 0.8m-1m, the lower base width is 1m-1.2m, and the height is 1.8m-2m; the cross-section of the chamber is arched or cylindrical, the projection surface of the chamber on the horizontal plane is a circle of 2m-2.5m, and the distance between the highest point of the inner top surface of the chamber and the inner bottom surface of the chamber is 2.5m.

[0016] Preferably, in S3, the liquid collecting tunnel is supported and protected by logs, and the chamber is supported and supported by logs and beams, and protected by wire mesh.

[0017] Preferably, in S4, the guide element maintains a slope of 3‰-7‰ with the horizontal plane, and the guide element includes a guide hole and two grooves, one end of the two grooves are connected to the guide hole, the two grooves are "V" shaped, and the angle between the two grooves is 120°-160°.

[0018] Preferably, in S4, the guide holes are opened around the outer circumference of the chamber, and the end of the groove away from the guide holes extends in a direction away from the center of the chamber, and the distance between adjacent grooves gradually increases from approaching to away from the chamber.

[0019] Preferably, in S4, when constructing the diversion hole and the groove, a kilometer drill and a high-pressure water jet are used to break the ground together, and the kilometer drill has a built-in direction-changing gear.

[0020] Preferably, in S5, during the anti-seepage treatment, a high-pressure pump is used for grouting at the bottom of the guide element for anti-seepage, and a concrete canvas is used for the bottom of the chamber and the liquid collecting tunnel for anti-seepage.

[0021] Preferably, in S5, during the anti-blocking treatment, an isolation layer is first erected with logs and formwork at the bottom of the chamber and the liquid collecting tunnel after the anti-seepage treatment, and then fluffy materials are filled in the upper gaps of the isolation layer.

[0022] Compared with the prior art, the present invention has achieved the following technical effects:

[0023] The present invention provides a chamber-based liquid collection process for ionic rare earth in-situ leaching. At the foot of the ionic rare earth mine, a liquid collection tunnel is excavated along the ridgeline to the middle of the horizontal projection of the mountain. The tunnel is supported, and a chamber is excavated at the middle of the horizontal projection of the mountain and at the end of the tunnel. A diversion element is excavated horizontally and upwardly around the chamber, and a vertical downward drainage trough is excavated at the opening of the diversion element to the bottom of the chamber. A liquid collection trench is excavated circumferentially around the bottom of the chamber and in the middle of the bottom of the collection tunnel. The diversion element, drainage trough, collection trench, chamber, and collection tunnel are treated with anti-seepage and anti-blocking treatment. This process is simple, does not require large-scale mountain excavation or large-scale equipment, and reduces engineering workload by over 50% compared to existing interception processes for ionic rare earth in-situ leaching under complex geological conditions, thereby lowering production costs. Through the above process, an effective seepage free surface is formed inside the ore body to intercept the leachate flowing through the seepage free surface, thereby realizing efficient collection of the leachate, making the leachate recovery rate reach more than 90%, and improving the economic benefits of the ionic rare earth mine. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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.

[0025] Figure 1 It is a longitudinal sectional view of the arrangement structure of the ionic rare earth in-situ leaching chamber liquid collection process provided by the present invention;

[0026] Figure 2 This is a main view of the liquid collection tunnel arranged in the ionic rare earth in-situ leaching chamber liquid collection process provided by the present invention;

[0027] Figure 3 This is a front view of the flow guide element arranged in the ionic rare earth in-situ leaching chamber liquid collection process provided by the present invention;

[0028] Figure 4 It is a top view of the arrangement structure of the ionic rare earth in-situ leaching chamber liquid collection process provided by the present invention;

[0029] In the figure: 1-topsoil layer, 2-ore body, 3-semi-weathered layer, 4-bedrock, 5-liquid collecting tunnel, 6-chamber, 7-diversion element, 8-liquid collecting ditch, 9-diversion hole, 10-groove, 11-drainage trough. DETAILED DESCRIPTION

[0030] 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.

[0031] The purpose of the present invention is to provide a chamber liquid collection process for ionic rare earth in-situ leaching to solve the technical problems of difficult recovery of leachate from in-situ leaching of ionic rare earth mines under complex geological conditions and large engineering workload of interception process.

[0032] 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.

[0033] like Figures 1-4 As shown, this embodiment provides an ionic rare earth in-situ leaching chamber liquid collection process, which is mainly targeted at fully covered ionic rare earth mines without a good natural liquid collection bottom plate. Ionic rare earth mines under complex geological conditions include fully covered ionic rare earth mines where no unweathered bedrock 4 is exposed on the erosion base surface at the bottom of the ore body 2 and the burial depth of the bedrock 4 is unknown; and barefoot ionic rare earth mines where bedrock 4 is exposed on the erosion base surface but is far from the bottom of the ore body 2. From the outside to the inside, the ionic rare earth mine is composed of the topsoil layer 1, the ore body 2, the semi-weathered layer 3, and the base layer 4. The ionic rare earth in-situ leaching chamber liquid collection process includes the following steps:

[0034] S1, depending on the occurrence location of the ionic rare earth ore body 2, a liquid collection tunnel 5 is excavated at the foot or mountainside of the ionic rare earth mine. The liquid collection tunnel 5 enters horizontally along the ridge line. The liquid collection tunnel 5 and the chamber 6 are both located in the semi-weathered layer 3 below the ore body 2 and above the bedrock 4, and the distance between the liquid collection tunnel 5 and the chamber 6 and the bottom surface of the ore body 2 is not more than 2m, so as to shorten the seepage path of the leachate in the ore-free layer. The bottom surface of the liquid collection tunnel 5 maintains a slope of 3‰-7‰ with the horizontal plane, preferably 3‰, to facilitate the discharge of the collected leachate to the outside of the mountain. The cross-section of the liquid collection tunnel 5 is trapezoidal, with an upper bottom of 0.8m to 1m, preferably 0.8m, a lower bottom of 1m to 1.2m, preferably 1m, and a height of 1.8m, which is convenient for the transportation of earthwork and the entry and exit of personnel. The liquid collection tunnel 5 is excavated to the middle of the horizontal projection surface of the ore body 2;

[0035] S2, after the liquid collection tunnel 5 is excavated, logs are used to support the sides and top of the liquid collection tunnel 5. Logs are used to support and erect beams. Plates are used to connect and secure adjacent pillars and beams. Weeds are inserted into the gaps between the plate and the wall of the liquid collection tunnel 5.

[0036] S3: Excavate chamber 6 at the end of liquid collection tunnel 5. To ensure construction safety, excavate chamber 6 in two stages. With liquid collection tunnel 5 as the axis of symmetry, excavate one side of liquid collection tunnel 5 first. After forming chamber 6 with a semicircular horizontal projection, immediately support it with logs and set up beams. Stainless steel wire mesh is laid between the beams at the top of chamber 6. The gap between the stainless steel wire mesh and the wall of chamber 6 is filled with weeds. After completing construction on one side, proceed to the other side using the same steps.

[0037] S4, using the improved drill bit and drilling rig, vertically dig the diversion element 7 on the wall of the chamber 6 or on the horizontal section of the wall of the chamber 6, and keep the slope of the diversion element 7 with the horizontal plane at 3‰ to 7‰, wherein the diameter of the diversion hole 9 is 0.1m, the thickness of the groove 10 (i.e., the distance between the two inner walls of the groove 10) is 0.01m to 0.03m, preferably 0.02m, the width of the groove 10 is 0.4m to 0.6m, preferably 0.5m, the spacing between adjacent diversion holes 9 on the wall of the chamber 6 is 0.5m to 0.7m, preferably 0.6m, and the depth of the groove 10 depends on the projection range of the overlying ore body 2. Generally, it exceeds the projection range of the ore body 2 by 1m to 3m. From the direction close to the chamber 6 to the direction away from the chamber 6, the grooves 10 are scattered around the chamber 6. After the diversion hole 9 is excavated, a drainage groove 11 is excavated vertically downward at the mouth of the diversion hole 9. The drainage groove 11 is 0.1m to 0.15m wide, preferably 0.15m, and 0.1m deep. The drainage groove 11 is excavated to the bottom of the chamber 6, and then a liquid collection ditch 8 is excavated at the bottom of the chamber 6 along the bottom of the chamber 6. The liquid collection ditch 8 is 0.3m wide and 0.3m deep. The liquid collection ditch 8 converges at the middle position of the bottom of the liquid collection roadway 5 and extends along the center line of the bottom of the liquid collection roadway 5 to the entrance and exit of the liquid collection roadway 5;

[0038] S5, after the above process is completed, the diversion hole 9, the groove 10, the chamber 6, the liquid collecting ditch 8 and the liquid collecting roadway 5 are treated for anti-seepage. The diversion hole 9 and the groove 10 are treated with high-pressure grouting for anti-seepage. The slurry is made of a mixture of plugging king and water in a mass ratio of 1:3. The main components of the plugging king are sulphoaluminate cement, quartz sand powder, calcium chloride, lithium chloride, hydroxypropyl methylcellulose, water reducer, etc. The bottom of the chamber 6, the liquid collecting ditch 8 and the liquid collecting roadway 5 are covered with concrete canvas for anti-seepage. The main components of the concrete canvas are The drainage trough 11 is made of polyethylene, polypropylene and polyvinyl chloride fibers, calcium aluminate cement, etc., and the wall of the drainage trough 11 is hung with wire mesh, and then concrete is sprayed for anti-seepage. After the anti-seepage treatment, the chamber 6 and the liquid collection tunnel 5 are treated to prevent blocking. Logs and wooden boards are used to build an air barrier at the bottom of the chamber 6 and the liquid collection tunnel 5. The air barrier and the top of the chamber 6 and the liquid collection tunnel 5 are filled with weeds, branches and other fluffy materials. After all the processes are completed, the entrance and exit of the liquid collection tunnel 5 are blocked with drill blocks and concrete, leaving only the discharge outlet of the liquid collection ditch 8.

[0039] Specifically, the cross-sectional shape of the chamber 6 is cylindrical or arched, and the projection surface of the chamber 6 on the horizontal plane is a circle of 2m-2.5m, preferably 2m, and the distance between the highest point of the top surface of the chamber 6 and the inner bottom surface of the chamber 6 is 2.5m, which meets the mechanical construction requirements of the guide element 7. The design of the shape and the selection of the size of the chamber 6 take into account stability, cost, the construction of the guide holes 9 and the grooves 10, and the expansion of the intercepting area as much as possible. The shape and size can be appropriately adjusted according to the geotechnical conditions during the actual construction process, and the purpose remains unchanged.

[0040] In S4, the slope between the diversion element 7 and the horizontal plane is maintained at 3‰-7‰. The diversion element 7 includes a diversion hole 9 and two grooves 10. The grooves 10 are located in the upper semicircular arc of the diversion hole 9 (in actual construction, the diversion hole 9 is a long hole drilled from outside the mountain to inside the mountain, and the grooves 10 are grooves opened in the upper semicircular arc of the diversion hole 9). One end of the two grooves 10 is connected to the diversion hole 9. The two grooves 10 are "V"-shaped, and the angle between the two grooves 10 is 120°-160°. The diversion hole 9 and the grooves 10 are integrally formed by an improved drill bit and drilling rig. There is no need to first excavate the diversion hole 9 and then form grooves 10 on both sides of the diversion hole 9.

[0041] The ionic rare earth in-situ leaching chamber liquid collection process in this embodiment is used:

[0042] (1) Simple process and easy implementation. This embodiment does not require large-scale mountain excavation and large-scale equipment construction, and the engineering workload is reduced by more than 50% compared with the existing interception process for ionic rare earth in-situ leaching under complex geological conditions.

[0043] (2) High construction efficiency and good anti-seepage effect. This embodiment uses a drilling rig with integrated diversion holes 9 and grooves 10. The excavation efficiency of the diversion holes 9 and grooves 10 is increased by more than 50%. Different anti-seepage materials are used for different processes, and leachate leakage is reduced by more than 30%, thereby reducing environmental pollution caused by leachate leakage.

[0044] (3) High leachate recovery rate and low implementation cost. This embodiment achieves a leachate recovery rate of over 90%, and the implementation cost is reduced by 50% compared to the existing interception process for ionic rare earth in-situ leaching under complex geological conditions, thereby improving the economic benefits of ionic rare earth mines.

[0045] This specification 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. An ionic rare earth in-situ leaching chamber liquid collection process, characterized by: The following steps are involved: S1, at the foot of the ionic rare earth mine, a liquid collection tunnel is excavated along the ridge line to the middle of the horizontal projection of the mountain; S2, supporting the liquid collecting roadway; S3, excavating a chamber in the middle of the horizontal projection of the mountain and at the end of the liquid collection roadway, and supporting the chamber; the chamber is excavated in a side-by-side manner, with the liquid collection roadway as the axis of symmetry, and excavated first on one side of the liquid collection roadway to form the chamber with a semicircular horizontal projection. After that, logs are immediately used to support and set up beams, stainless steel wire mesh is laid between the beams at the top of the chamber, and the gap between the stainless steel wire mesh and the chamber wall is filled with weeds. After the construction on one side of the chamber is completed, the other side of the chamber is constructed according to the same steps; S4, excavating a diversion element horizontally and obliquely upward around the chamber, excavating a vertical downward drainage groove at the opening of the diversion element to the bottom of the chamber, and excavating a liquid collection groove around the bottom of the chamber and between the bottom of the liquid collection roadway; S5, performing anti-seepage and anti-blocking treatment on the guide element, the drainage trough, the liquid collecting ditch, the chamber and the liquid collecting tunnel.

2. The ionic rare earth in-situ leaching chamber liquid collection process according to claim 1, characterized in that: In S3, the liquid collection tunnel and the chamber are both located in the semi-weathered layer below the ore body and above the bedrock, and the distance between the liquid collection tunnel and the chamber and the bottom surface of the ore body is not greater than 2m.

3. The ionic rare earth in-situ leaching chamber liquid collection process according to claim 1, characterized in that: In S3, the bottom surface of the liquid collecting tunnel and the bottom surface of the chamber maintain a slope of 3‰-7‰ with the horizontal plane.

4. The ionic rare earth in-situ leaching chamber liquid collection process according to claim 1, characterized in that: In S3, the cross-section of the liquid collection channel is trapezoidal, and the upper base of the liquid collection channel is 0.8m-1m, the lower base width is 1m-1.2m, and the height is 1.8m-2m; the cross-section of the chamber is arched, the projection surface of the chamber on the horizontal plane is a circle of 2m-2.5m, and the distance between the highest point of the inner top surface of the chamber and the inner bottom surface of the chamber is 2.5m.

5. The ionic rare earth in-situ leaching chamber liquid collection process according to claim 1, characterized in that: In S3, the liquid collecting tunnel is supported and protected by logs.

6. The ionic rare earth in-situ leaching chamber liquid collection process according to claim 1, characterized in that: In S4, the guide element maintains a slope of 3‰-7‰ with the horizontal plane, and the guide element includes a guide hole and two grooves. One end of the two grooves is connected to the guide hole, the two grooves are "V" shaped, and the angle between the two grooves is 120°-160°.

7. The ionic rare earth in-situ leaching chamber liquid collection process according to claim 6, characterized in that: In S4, the guide holes are opened around the outer circumference of the chamber, and the end of the groove away from the guide holes extends in a direction away from the center of the chamber. From approaching to away from the chamber, the distance between adjacent grooves gradually increases.

8. The ionic rare earth in-situ leaching chamber liquid collection process according to claim 6, characterized in that: In S4, when constructing the diversion hole and the groove, a kilometer drill and a high-pressure water jet are used to break the soil, and the kilometer drill has a built-in direction-changing gear.

9. The ionic rare earth in-situ leaching chamber liquid collection process according to claim 1, characterized in that: In S5, during the anti-seepage treatment, a high-pressure pump is used to inject grout at the bottom of the guide element for anti-seepage, and a concrete canvas is used to cover the bottom of the chamber and the liquid collecting tunnel for anti-seepage.

10. The ionic rare earth in-situ leaching chamber liquid collection process according to claim 1, characterized in that: In S5, during the anti-blocking treatment, an isolation layer is first erected with logs and templates at the bottom of the chamber and the liquid collecting tunnel after the anti-seepage treatment, and then fluffy materials are filled in the gaps above the isolation layer.

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