Treatment method for accelerating rapid sedimentation and consolidation of bauxite mud

Abstract

The invention belongs to the technical field of rapid consolidation and sedimentation of tailing mud, and provides a treatment method for accelerating rapid sedimentation and consolidation of bauxite mud, which comprises the following steps: laying a lower sand cushion layer at the bottom of a to-be-treated area; one end of a second branch pipe is embedded in the lower cushion layer; one end, far away from the lower cushion layer, of the second branch pipe is communicated with a vacuum pump; a plurality of sand wells are vertically arranged in the to-be-treated area at certain intervals, the bottoms of the sand wells penetrate into the lower sand cushion layer, then the to-be-treated area is filled with bauxite mud, and it is ensured that the top of each sand well is higher than the landfill depth of the bauxite mud; an upper-layer sand cushion layer is laid on the top of the bauxite mud, the top of the sand well extends into the upper-layer sand cushion layer, and a sealing film is laid on the top of the upper-layer sand cushion layer; and starting the vacuum pump to discharge air and water in the bauxite mud. According to the invention, the bauxite mud can be efficiently, economically and environment-friendly treated and resourcefully utilized.

Description

Technical Field

[0001] The invention belongs to the technical field of rapid consolidation and sedimentation of tailings slurry, and in particular relates to a treatment method for accelerating rapid sedimentation and consolidation of bauxite slurry. Background Art

[0002] Bauxite mud, as an important by-product in the processing of bauxite, mainly consists of a large amount of clay and metal oxides, which has extremely high industrial utilization potential and environmental protection treatment challenges. Traditionally, this type of mud is often simply piled up in tailings ponds in the open air. However, with the increasing scale of bauxite mining and processing, the stock of mud in tailings ponds continues to accumulate, bringing a series of problems that need to be solved urgently.

[0003] The bauxite mud in the closed tailings pond exhibits a series of unique physical and mechanical properties. Its water content is extremely high, and its compressibility and porosity are also significant, resulting in the overall low strength and low permeability of the mud. What is more complicated is that the particle size of the mud is extremely small and the plasticity index remains high, making it difficult for the soil particles to form a stable and solid structural skeleton. This characteristic not only increases the difficulty of sedimentation and consolidation of the mud, but also seriously threatens the overall stability of the tailings pond. With the continuous increase in the stock of mud, the problem of land resource occupation by tailings ponds has become increasingly prominent. A large amount of land resources are used to stack these difficult-to-handle muds, which not only wastes precious land resources, but also exacerbates the contradiction between man and nature. What is more serious is that the tailings pond is at risk of dam collapse and leakage at any time. Once an accident occurs, it will cause immeasurable damage to the surrounding environment and residents' lives.

[0004] In order to accelerate the separation of soil and water in bauxite mud and improve the consolidation and drainage efficiency, a variety of methods have been widely used or studied. The following are several common methods for accelerating the consolidation and drainage of mud:

[0005] 1. Adding flocculants: This method adds an appropriate amount of flocculants to the sludge, and uses the bridging effect of the flocculants to cause multiple particles to adsorb on the polymer substances, thereby forming larger flocs. These flocs have better sedimentation properties and can achieve rapid sedimentation and effective dehydration of the sludge;

[0006] 2. Filter pressing: Filter pressing is a physical method to remove water from sludge by applying pressure. During the filtration process, the sludge is placed on a filter cloth or filter screen, and the water in the sludge is squeezed out by applying external pressure, thereby achieving solid-liquid separation. Filter pressing has the advantages of large processing capacity, high efficiency, and small footprint;

[0007] 3. Sludge solidification: Sludge solidification is a method of changing the physical and chemical properties of sludge by adding a solidifying agent. Commonly used solidifying agents include cement, fly ash, lime and other materials, which can be used alone or in combination. By chemically reacting or physically interacting with substances such as water in the sludge, the solidifying agent can convert the sludge into a stable and harmless solid substance. Sludge solidification can not only effectively reduce the water content of the sludge and improve its mechanical strength, but also reduce pollution and damage to the environment;

[0008] However, these methods have obvious shortcomings in actual operation, which limits their further promotion and application.

[0009] 1. Adding flocculants: In actual industrial applications, the effect evaluation, safety considerations and environmental performance verification are still insufficient. First, the effect of flocculants is easily affected by water quality conditions (such as pH value, temperature, ionic strength, etc.), resulting in unstable treatment effects. Secondly, in order to obtain the best treatment effect, key parameters such as dosage and mixing time need to be precisely controlled, which increases the complexity and cost of the operation. In addition, the use of flocculants may also cause certain corrosion to the treatment equipment, further increasing the difficulty and cost of actual application;

[0010] 2. Filter press method: Filter press equipment is more expensive than other separation equipment, which increases the initial investment pressure of the enterprise. At the same time, during long-term use, the filter press equipment needs to be kept clean and regularly maintained to ensure its normal operation and extend its service life. This not only increases the operating costs of the enterprise, but may also lead to a decrease in processing efficiency. In addition, the filter press method consumes a lot of resources when processing sludge, and the effect is not obvious, especially for bauxite sludge with high water content and high viscosity, its treatment effect is even more limited;

[0011] 3. Sludge solidification: The solidification effect is affected by many factors, such as the selection, dosage, reaction conditions, etc. of the curing agent, which makes it difficult to ensure the stability and consistency of the curing effect. In addition, the cost of some curing agents is too high, which increases the processing cost of the enterprise. What is more serious is that some harmful substances or waste gases may be generated during the solidification process of the sludge, causing secondary pollution to the environment, which violates the original intention of environmental protection treatment.

[0012] In summary, the existing methods for accelerating the consolidation and drainage of bauxite mud have obvious shortcomings, which limits their application in the field of bauxite mud treatment. Therefore, there is an urgent need for a treatment method for accelerating the rapid sedimentation and consolidation of bauxite mud to achieve efficient, economical and environmentally friendly treatment and resource utilization of bauxite mud. Summary of the invention

[0013] The purpose of the present invention is to provide a method for accelerating the rapid sedimentation and consolidation of bauxite mud, so as to solve the above-mentioned problems and achieve the purpose of efficient, economical and environmentally friendly treatment and resource utilization of bauxite mud.

[0014] To achieve the above object, the present invention provides the following scheme: a method for accelerating the rapid sedimentation and consolidation of bauxite mud, the operating steps comprising:

[0015] Laying a lower sand cushion layer at the bottom of the area to be treated;

[0016] One end of the second branch pipe is buried in the lower cushion layer, and one end of the second branch pipe away from the lower cushion layer is connected to the vacuum pump;

[0017] A number of sand wells are vertically arranged at certain intervals in the area to be treated, and the bottoms of the sand wells are deep into the lower sand cushion layer. After that, the bauxite mud is filled into the area to be treated, and it is ensured that the top of the sand well is higher than the landfill depth of the bauxite mud;

[0018] An upper sand cushion layer is laid on the top of the bauxite mud so that the top of the sand well extends into the upper sand cushion layer, and a sealing membrane is laid on the top of the upper sand cushion layer;

[0019] Start the vacuum pump to discharge the air and water in the bauxite mud.

[0020] Preferably, a first geotextile is laid on the top and bottom of the lower sand cushion layer, respectively, and the bottom of the sand well penetrates the first geotextile on the top of the lower sand cushion layer and penetrates into the lower sand cushion layer.

[0021] Preferably, a second geotextile is laid on the top and bottom of the upper sand cushion layer, respectively, the top of the sand well penetrates the second geotextile at the bottom of the upper sand cushion layer and extends into the upper sand cushion layer, and the sealing membrane is laid on the second geotextile at the top of the upper sand cushion layer.

[0022] Preferably, the material of the lower sand cushion layer and the upper sand cushion layer is standard sand, or fine sand with a permeability coefficient exceeding 0.0 cm / s.

[0023] Preferably, the circumferential side wall of the sand well needs to be wrapped with a geotextile, and the interface between the sand well and the first geotextile and the second geotextile needs to be wrapped with an additional geotextile for a second time.

[0024] Preferably, the ratio of the diameter of the sand well to the radius of the area to be treated is 0.1;

[0025] The interval between two adjacent sand wells is 2m.

[0026] Preferably, a sealing trench is dug on the land outside the area to be treated, and the edge of the sealing film is pressed into the sealing trench to form a closed space.

[0027] Preferably, the thickness of the upper sand cushion layer and the lower sand cushion layer is 5 cm.

[0028] Preferably, the edge of the second geotextile at the bottom of the upper sand cushion layer exceeds the edge of the area to be treated.

[0029] Preferably, the air inlet end of the vacuum pump is connected to one end of a first branch pipe, and the other end of the first branch pipe is connected to an end of the second branch pipe away from the lower sand cushion layer through a water-gas separation tank.

[0030] Compared with the prior art, the present invention has the following advantages and technical effects:

[0031] 1. Efficient sedimentation acceleration: The present invention constructs a stable vacuum environment in the sand well and cushion system, and utilizes the strong suction effect of vacuum negative pressure to quickly discharge the gas and free water in the pores of the sludge. This process significantly accelerates the close arrangement and sedimentation of the sludge particles, achieves a significant reduction in water content (from more than 200% in the normal state to about 60%), greatly shortens the sedimentation cycle, and improves the processing efficiency.

[0032] 2. Simplified equipment and convenient operation: Compared with traditional processing technology, the equipment configuration adopted by the present invention is more streamlined, the operation process is simple and easy, and the dependence on complex equipment and high maintenance costs are reduced. This not only simplifies the complexity of technical implementation, but also improves the flexibility and reliability of operation.

[0033] 3. Significant environmental benefits: During the entire treatment process, the treatment method of the present invention does not generate any additional engineering waste or harmful pollutants, effectively avoiding environmental pollution problems, and significantly reducing subsequent environmental treatment costs and management burdens, demonstrating good environmental friendliness.

[0034] 4. Significant improvement in foundation performance: The physical and mechanical properties of the sludge foundation treated by the present invention have been significantly improved. The shear strength of the cross plate is as high as 26kPa, which fully meets the stringent requirements of the subsequent secondary consolidation on foundation strength. This result not only verifies the excellent performance of this method in accelerating sludge settlement, but also further enhances the stability and durability of the foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0036] Figure 1 It is a schematic diagram of the construction system of the present invention;

[0037] Among them, 1. bauxite mud; 2. sand well; 3. lower sand cushion layer; 4. vacuum pump; 5. first branch pipe; 6. connecting valve; 7. water-gas separation tank; 8. sealing membrane; 9. upper sand cushion layer; 10. sealing ditch; 11. first geotextile; 12. second branch pipe; 13. second geotextile. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0039] 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.

[0040] Reference Figure 1 The present invention provides a method for accelerating the rapid sedimentation and consolidation of bauxite mud, and the operation steps include:

[0041] Laying a lower sand cushion layer 3 at the bottom of the area to be treated;

[0042] One end of the second branch pipe 12 is buried in the lower sand cushion layer 3, and one end of the second branch pipe 12 away from the lower sand cushion layer 3 is connected to the vacuum pump 4;

[0043] A plurality of sand wells 2 are vertically arranged at a certain interval in the area to be treated, and the bottoms of the plurality of sand wells 2 are deep into the lower sand cushion layer 3. Afterwards, the bauxite mud 1 is filled into the area to be treated, and it is ensured that the top of the sand well 2 is higher than the landfill depth of the bauxite mud;

[0044] An upper sand cushion layer 9 is laid on the top of the bauxite mud 1, so that the top of the sand well 2 extends into the upper sand cushion layer 9, and a sealing film 8 is laid on the top of the upper sand cushion layer 9;

[0045] The vacuum pump 4 is started to discharge the air and water in the bauxite mud 1.

[0046] The main function of the lower sand cushion layer 3 is to act as a horizontal drainage plate; the main function of the vacuum pump 4 is to create a negative pressure environment in the entire drainage system through the lower sand cushion layer 3; the main function of the sand well 2 is to transmit vacuum in the drainage system; the main function of the upper sand cushion layer 9 is to horizontally conduct vacuum negative pressure. Overall, the present invention has achieved significant technical effects in the field of efficient sedimentation treatment of bauxite tailings slurry through innovatively improved vacuum preloading technology, and provides a new solution for research and application in related fields that is efficient, environmentally friendly, economical, and strengthens foundation performance.

[0047] At the same time, the bauxite mud is subjected to continuous vacuum negative pressure during consolidation and drainage, and the mud particles are rearranged, causing the mud to transform into an over-consolidated state, and the large pores are transformed into a denser small and medium pore structure, which makes the bauxite mud sample have obvious structural properties, that is, there is additional compression resistance caused by the initial soil skeleton structure, and therefore it exhibits compaction behavior.

[0048] To further optimize the solution, a drainage port is provided at the bottom of the lower sand cushion layer 3 , and one end of the second branch pipe 12 is extended into the lower sand cushion layer 3 through the drainage port.

[0049] To further optimize the solution, the first geotextile 11 is laid on the top and bottom of the lower sand cushion layer 3 respectively, and the bottom of the sand well 2 penetrates the first geotextile 11 on the top of the lower sand cushion layer 3 and penetrates into the lower sand cushion layer 3.

[0050] A first geotextile 11 is laid at the bottom of the lower sand cushion layer 3 as the first isolation layer. The main function of the first geotextile 11 on the top of the lower sand cushion layer 3 is to separate the lower sand cushion layer 3 from the upper structure to form a second isolation layer.

[0051] To further optimize the solution, a second geotextile 13 is laid on the top and bottom of the upper sand cushion layer 9 respectively, the top of the sand well 2 passes through the second geotextile 13 at the bottom of the upper sand cushion layer 9 and extends into the upper sand cushion layer 9, and the sealing membrane 8 is laid on the second geotextile 13 at the top of the upper sand cushion layer 9.

[0052] The second geotextile 13 at the bottom of the upper sand cushion layer 9 is used to isolate it from the bauxite mud 1, and the main function of the second geotextile 13 at the top of the upper sand cushion layer 9 is to separate it from the external environment.

[0053] To further optimize the solution, the material of the lower sand cushion layer 3 and the upper sand cushion layer 9 is standard sand, or fine sand with a permeability coefficient exceeding 0.01 cm / s.

[0054] As a further optimization plan, the circumferential side walls of the sand well 2 need to be wrapped with geotextiles, and the interfaces between the sand well 2 and the first geotextile 11 and the second geotextile 13 need to be wrapped with geotextiles for a second time.

[0055] Wrapping the outer wall of the sand well 2 with geotextile and additionally covering the interfaces between the sand well 2 and the upper sand cushion layer 9 and the lower sand cushion layer 3 with geotextile can prevent fine particles of bauxite mud from penetrating into the sand well 2 during the vacuuming process, causing clogging of the sand well 2 and hindering the vacuum transmission efficiency.

[0056] The vacuum transmission efficiency of the sand well 2 is high, the drainage rate is faster, and at the same time, the sand well 2 has a good anti-bending effect, which can better ensure the continuity of the drainage channel. This allows the sand well 2 to always ensure the vacuum degree during the consolidation process at a place far away from the drain outlet, so that the place far away from the drain outlet still shows a good consolidation effect.

[0057] Further optimizing the scheme, the ratio of the diameter of the sand well 2 to the radius of the area to be treated is 0.1;

[0058] The interval between two adjacent sand wells 2 is 2m.

[0059] To further optimize the solution, a sealing trench 10 is dug on the land outside the area to be treated, and the edge of the sealing film 8 is pressed into the sealing trench 10 to form a closed space.

[0060] According to the further optimization scheme, the thickness of the upper sand cushion layer 9 and the lower sand cushion layer 3 is 5 cm.

[0061] In a further optimized solution, the edge of the second geotextile 13 at the bottom of the upper sand cushion layer 9 exceeds the edge of the area to be treated.

[0062] To further optimize the solution, the air inlet end of the vacuum pump 4 is connected to one end of the first branch pipe 5 , and the other end of the first branch pipe 5 is connected to an end of the second branch pipe 12 away from the lower sand cushion layer 3 through the water-gas separation tank 7 .

[0063] The first branch pipe 5 and the second branch pipe 12 are respectively provided with connecting valves 6 .

[0064] Start the vacuum pump 4 to extract the air in the water-gas separation tank 7, generate negative pressure in the water-gas separation tank 7, and transfer it to the lower sand cushion layer 3 through the second branch pipe 12, and then transfer it to the upper sand cushion layer 9 through a number of sand wells 2. Under the action of vacuum negative pressure, the air and water in the bauxite mud 1 are quickly discharged from the second branch pipe 12 to the water-gas separation tank 7.

[0065] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0066] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for accelerating the rapid sedimentation and consolidation of bauxite mud, characterized in that: The steps include: Laying a lower sand cushion layer (3) at the bottom of the area to be treated; One end of a second branch pipe (12) is buried in the lower cushion layer (3), and one end of the second branch pipe (12) away from the lower cushion layer (3) is connected to a vacuum pump (4); A plurality of sand wells (2) are vertically arranged at a certain interval in the area to be treated, and the bottoms of the plurality of sand wells (2) are deeply embedded in the lower sand cushion layer (3). Afterwards, the bauxite mud (1) is filled into the area to be treated, and it is ensured that the top of the sand well (2) is higher than the landfill depth of the bauxite mud; An upper sand cushion layer (9) is laid on the top of the bauxite mud (1), so that the top of the sand well (2) extends into the upper sand cushion layer (9), and a sealing film (8) is laid on the top of the upper sand cushion layer (9); The vacuum pump (4) is started to discharge the air and water in the bauxite mud (1).

2. A method for accelerating the rapid sedimentation and consolidation of bauxite mud according to claim 1, characterized in that: The first geotextile (11) is laid on the top and bottom of the lower sand cushion layer (3), respectively, and the bottom of the sand well (2) penetrates the first geotextile (11) on the top of the lower sand cushion layer (3) and penetrates into the lower sand cushion layer (3).

3. A method for accelerating the rapid sedimentation and consolidation of bauxite mud according to claim 2, characterized in that: A second geotextile (13) is laid on the top and bottom of the upper sand cushion layer (9), respectively; the top of the sand well (2) passes through the second geotextile (13) at the bottom of the upper sand cushion layer (9) and extends into the upper sand cushion layer (9); and the sealing membrane (8) is laid on the second geotextile (13) at the top of the upper sand cushion layer (9).

4. The method for accelerating the rapid sedimentation and consolidation of bauxite mud according to claim 1, characterized in that: The materials of the lower sand cushion layer (3) and the upper sand cushion layer (9) are standard sand or fine sand with a permeability coefficient exceeding 0.01 cm / s.

5. The method for accelerating the rapid settling and consolidation of bauxite mud according to claim 3, characterized in that: The circumferential side wall of the sand well (2) needs to be wrapped with a geotextile, and the interface between the sand well (2) and the first geotextile (11) and the second geotextile (13) needs to be wrapped with an additional geotextile for a second time.

6. The method for accelerating the rapid settling and consolidation of bauxite mud according to claim 1, characterized in that: The ratio of the diameter of the sand well (2) to the radius of the area to be treated is 0.1; The interval between two adjacent sand wells (2) is 2m.

7. The method for accelerating the rapid settling and consolidation of bauxite mud according to claim 1, characterized in that: A sealing groove (10) is dug on the land outside the area to be treated, and the edge of the sealing film (8) is pressed into the sealing groove (10) to form a closed space.

8. The method for accelerating the rapid settling and consolidation of bauxite mud according to claim 1, characterized in that: The thickness of the upper sand cushion layer (9) and the lower sand cushion layer (3) is 5 cm.

9. The method for accelerating the rapid settling and consolidation of bauxite mud according to claim 3, characterized in that: The edge of the second geotextile (13) at the bottom of the upper sand cushion layer (9) exceeds the edge of the area to be treated.

10. The method for accelerating the rapid settling and consolidation of bauxite mud according to claim 1, characterized in that: The air inlet end of the vacuum pump (4) is connected to one end of a first branch pipe (5), and the other end of the first branch pipe (5) is connected to an end of the second branch pipe (12) away from the lower sand cushion layer (3) through a water-gas separation tank (7).

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