A waste mine restoration structure based on titanium gypsum and a restoration method

Abstract

The present application relates to the technical field of abandoned mine restoration, and particularly relates to a kind of abandoned mine restoration structure and restoration method based on titanium gypsum, comprising drainage pressure relief layer, impermeable liner, liquid flow guide layer, mine slurry filler layer and sealing surface soil layer from bottom to top in pit are sequentially arranged;The method of the present application uses polyurethane waterproof layer to realize the waterproof guarantee of the bottom lining, a large amount of impermeable material resources is saved by using titanium gypsum as the main material of impermeable liner, the waterproof performance of impermeable material can be improved by mixing titanium gypsum with modified montmorillonite, the compression resistance of impermeable liner can be improved by adding a certain proportion of microsilica powder and zeolite powder;The waterproof performance of impermeable material can be improved by modifying montmorillonite powder and mixing with titanium gypsum for filling;The groundwater in the pit is drained by using the drainage pressure relief layer, the accumulated water in the pit is drained in real time by using the liquid flow guide layer, and the surface of the pit is green constructed by using the sealing surface soil layer.

Description

Technical Field

[0001] This invention relates to the field of abandoned mine restoration technology, specifically to an abandoned mine restoration structure and method based on titanium gypsum. Background Technology

[0002] In recent years, with the gradual development of society, the restoration of abandoned mines in my country is still in the exploratory stage. The difficulty of restoration varies depending on the type of mine, and the restoration of a large number of abandoned mines remains to be solved.

[0003] Titanium gypsum is a waste residue mainly composed of dihydrate gypsum produced during the sulfuric acid process for producing titanium dioxide. In order to treat acidic wastewater, lime or carbide slag is added to neutralize a large amount of acidic wastewater. It can be used to make unfired bricks and as a cement retarder.

[0004] Large-scale enterprises produce over one million tons of titanium gypsum annually, but almost the entire amount is not effectively utilized. Methods of disposing of titanium gypsum, such as landfilling, not only occupy large amounts of land and pollute the environment, but also impose a significant economic burden on titanium dioxide enterprises. Furthermore, landfill disposal is costly and inefficient, contradicting my country's principle of solid waste resource utilization. Therefore, how to rationally utilize titanium gypsum has become an urgent problem to be solved. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a structure and method for the restoration of abandoned mines based on titanium gypsum.

[0006] The technical solution of the present invention is: an abandoned mine restoration structure based on titanium gypsum, comprising a drainage and pressure relief layer, an impermeable lining layer, a liquid diversion layer, a sludge filling layer and a sealing topsoil layer arranged sequentially from bottom to top in the mine pit;

[0007] The drainage and pressure relief layer includes multiple backflow prevention and pressure relief wells, and radial drainage blind drains connected to the backflow prevention and pressure relief wells; the drainage and pressure relief method is as follows: the groundwater is pumped into the backflow prevention and pressure relief wells, the accumulated water is dispersed by the radial drainage blind drains, drainage ditches and water storage tanks are set at intervals outside the mine pit, the slope of the pit is reinforced, and the accumulated water at the bottom of the mine pit is drained.

[0008] The impermeable lining includes a bottom lining, a polyurethane waterproof layer disposed on the bottom lining, and an impermeable material laid on the polyurethane waterproof layer; the bottom lining is sprayed with a polyurea coating with a thickness of 3-6 mm.

[0009] The thickness of the impermeable material is 500-1500 mm. The preparation method is as follows: by mass percentage, 80-90% titanium gypsum, 3-5% composite montmorillonite powder, 1-2% silica powder and the balance zeolite powder are mixed to obtain the impermeable material.

[0010] The preparation method of the composite montmorillonite powder is as follows: montmorillonite is crushed, and 70-80% of montmorillonite powder, 0.5-1.5% of hexadecyltrimethylammonium bromide, and the remainder of high molecular weight surfactant are taken by mass percentage, mixed evenly, and then put into an extruder for extrusion treatment. After crushing, composite montmorillonite powder is obtained.

[0011] The liquid guiding layer includes a radial well connected to the drainage ditch and the water storage tank via a conduit, and a longitudinal blind pipe set along the boundary of the mine pit. Several longitudinal blind pipes are each connected to the main blind pipe, and the end of the main blind pipe is connected to the drainage ditch and the water storage tank along the slope.

[0012] The sludge filler layer is filled with a mixture of industrial solid waste and functional fillers in equal mass ratios;

[0013] The sealing topsoil layer includes a clay layer with a thickness of 200-1500 mm covering the upper surface of the sludge filler layer, and a topsoil layer with a thickness of 400-2000 mm covering the upper surface of the clay.

[0014] Furthermore, the extruder used in the preparation method of the composite montmorillonite powder is a screw extruder, and its process parameters are: set temperature 110~120℃, screw speed 45~85r / min, and extrusion time 10~12min.

[0015] Note: A screw extruder is used to extrude montmorillonite powder, hexadecyltrimethylammonium bromide, and a high molecular weight surfactant, which can quickly mix and extrude the powder to produce modified montmorillonite powder.

[0016] Furthermore, both the backflow prevention and pressure relief wells and the radial wells are constructed using reinforced concrete as the well body material.

[0017] Note: Using reinforced concrete as the well body material results in good structural stability, corrosion resistance, and wear resistance.

[0018] Furthermore, the functional filler comprises, by mass percentage: 30-40% bentonite, 5-15% dehydrated aluminum salt, 1-3% water, 10-20% aggregate, 3-5% antifreeze agent, and the balance cement.

[0019] Explanation: Adding bentonite increases the waterproofness of the filler, adding dehydrated aluminum salts improves the compactness of the filler, adding aggregates and cement increases the stabilization effect, and adding antifreeze ensures the repair effect of the mine in low-temperature weather.

[0020] Furthermore, the dehydrated aluminum salt is made of aluminum sulfate, aluminum chloride, potassium aluminum sulfate and ferric chloride in a mass ratio of 1-2:2-3:1:1, or a dehydrated crystalline salt of aluminum chloride, or a dehydrated crystalline salt of ferric sulfate, aluminum chloride and aluminum sulfate in an equal mass ratio.

[0021] Note: The use of dehydrated aluminum salts can improve the compactness of waterproof mortar and enhance the impermeability and water resistance of the filler through their own micro-expansion properties.

[0022] Furthermore, the aggregate is any one or a combination of two or more of the following: sea sand, river sand, stone powder, mineral sand, and quartz sand; the aggregate has two particle sizes, namely 50-55 mesh and 80-85 mesh, and the ratio of the two particle sizes is 2-3:1.

[0023] Note: Adding aggregate can enhance the stability of the filler.

[0024] Furthermore, the antifreeze is a mixture of calcium chloride, magnesium chloride, and sodium chloride in a mass ratio of 1 to 3:1:1;

[0025] The cement is selected from any one or more of the following: PII42.5 silicate cement, PC32.5 cement, P.O42.5R ordinary silicate cement, and low-alkalinity sulfoaluminate cement with a strength grade of 42.5.

[0026] Note: Using a mixture of calcium chloride, magnesium chloride, and sodium chloride can enhance the freeze-thaw resistance of the packing material, and its selection can give the packing material higher impermeability and flexural and compressive strength.

[0027] Furthermore, the bottom liner is made of stainless steel; the filling density of the waterproofing material is controlled to be 93-98%.

[0028] Note: Stainless steel is used to enhance the waterproofness, corrosion resistance, and compressive strength of the impermeable lining, and the filling compaction is controlled to enhance the impermeability of the titanium plaster.

[0029] Furthermore, a method for remediating abandoned mines based on titanium gypsum includes the following steps:

[0030] S1. First, a drainage and pressure relief layer is laid in the mine pit for drainage and pressure relief. The drainage and pressure relief method is as follows: the groundwater is pumped into the anti-backflow pressure relief well using a pump body, the accumulated water is dispersed using radial drainage blind pipes, drainage ditches and water storage tanks are set at intervals outside the mine pit, the slope of the pit is reinforced, and the accumulated water at the bottom of the mine pit is drained.

[0031] S2. Lay an impermeable lining on the drainage and pressure relief layer: Evenly lay the bottom lining inside the mine pit, spray a polyurea coating with a thickness of 3-6mm on the bottom lining, then lay a polyurethane waterproof layer on the bottom lining, and then lay an impermeable material with a thickness of 500-1500mm on the polyurethane waterproof layer.

[0032] S3. Lay a liquid diversion layer on the seepage-proof lining: Set up several radial wells on the side of the mine pit, and connect the drainage ditch and water storage tank to the radial wells through conduits. Set up several longitudinal blind pipes along the boundary of the mine pit, and connect the longitudinal blind pipes to the main blind pipe. The end of the main blind pipe is connected to the drainage ditch and water storage tank along the slope. After collecting the leachate through the longitudinal blind pipes, it is introduced into the main blind pipe and sent into the drainage ditch and water storage tank. Excess water is introduced into the radial wells through conduits.

[0033] S4. Industrial solid waste and functional fillers are mixed in equal mass ratios to obtain sludge filler, and the sludge filler is laid on the liquid guide layer to form a sludge filler layer.

[0034] S5. Lay a clay layer with a thickness of 200-1500mm on the sludge filler layer, and then cover the clay layer with a topsoil layer with a thickness of 400-2000mm to form the sealing topsoil layer.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] (1) The method of the present invention uses a polyurethane waterproof layer to achieve waterproof protection for the bottom lining, uses environmentally friendly materials, and protects the natural environment; by using titanium gypsum as the main material of the anti-seepage lining, a large amount of anti-seepage material resources are saved. In addition, the anti-seepage lining of most industrial solid waste landfills generally requires a large amount of clay resources, which wastes a lot of clay resources and has high economic costs. Using titanium gypsum as the raw material for the anti-seepage lining is abundant and makes full use of solid waste resources. It not only saves a lot of disposal costs for the titanium dioxide industry, but also saves a lot of raw materials and resources for mine restoration. By mixing titanium gypsum with modified montmorillonite, the waterproof performance of the anti-seepage material can be enhanced. Adding a certain proportion of microsilica powder and zeolite powder can enhance the compressive strength of the anti-seepage lining.

[0037] (2) The method of this invention utilizes titanium gypsum as an impermeable lining to repair abandoned mines, realizing the green concept of solid waste resource utilization. This will improve the local ecological environment quality for the construction of green mines and ecological civilization, and promote the development of the industry and local economy and the improvement of the social green concept. Hexadecyltrimethylammonium bromide is a cationic surfactant. By using hexadecyltrimethylammonium bromide and polymer surfactant to modify montmorillonite powder, the porosity of the montmorillonite surface can be changed. When mixed with titanium gypsum, it can enhance the waterproof performance of the impermeable material. The drainage and pressure relief layer is used to drain the groundwater in the mine pit to avoid affecting the subsequent landfill repair work. The liquid diversion layer is used to drain the water in the mine pit in real time. The topsoil layer is used to construct a green structure on the surface of the mine pit, maintain the natural environment and enhance the repair effect of abandoned mines. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0039] Among them, 1-drainage and pressure relief layer, 2-seepage-proof lining layer, 21-bottom lining sheet, 22-polyurethane waterproof layer, 3-liquid diversion layer, 4-mineral mud filler layer, and 5-sealing topsoil layer. Detailed Implementation

[0040] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.

[0041] Example 1

[0042] like Figure 1 The structure shown is a waste mine remediation structure based on titanium gypsum, which consists of a drainage and pressure relief layer 1, an impermeable lining layer 2, a liquid diversion layer 3, a sludge filling layer 4, and a sealing topsoil layer 5 arranged sequentially from bottom to top in the mine pit.

[0043] The drainage and pressure relief layer 1 includes multiple anti-backflow pressure relief wells and radial drainage blind trenches connected to the anti-backflow pressure relief wells;

[0044] The seepage-proof lining 2 includes a bottom lining 21, a polyurethane waterproof layer 22 disposed on the bottom lining 21, and a seepage-proof material laid on the polyurethane waterproof layer 22; the bottom lining 21 is sprayed with a polyurea coating with a thickness of 4.5mm.

[0045] The bottom liner 21 is made of stainless steel; the filling compactness of the waterproofing material is controlled to be 95.5%;

[0046] The impermeable material has a thickness of 1000mm and is prepared by mixing 85% titanium gypsum, 4% composite montmorillonite powder, 1.5% silica powder, and the remainder zeolite powder by weight percentage. The titanium gypsum in the impermeable lining 1 comes from a titanium dioxide production enterprise in Anhui Province. The abandoned mine is located in a prefecture-level city in Anhui Province. Taking a local iron ore mine remediation project that complies with local planning as an example, the lowest elevation of the bottom of the abandoned mine pit is -10m, the design elevation of the south side of the mine pit closure is +50m, the design elevation of the north side closure is +75m, the pit depth is approximately 50m, and the upper opening area is 16hm². 2 The lower area is 8.48 hm² 2 The total storage capacity is approximately 7.92 million cubic meters. 3 The effective utilization rate is approximately 0.9.

[0047] The preparation method of the composite montmorillonite powder is as follows: montmorillonite is crushed, and 75% of montmorillonite powder, 1% of hexadecyltrimethylammonium bromide, and the remainder of high molecular weight surfactant are taken by mass percentage, mixed evenly, and then put into an extruder for extrusion treatment. After crushing, composite montmorillonite powder is obtained.

[0048] The extruder used in the preparation method of the composite montmorillonite powder is a screw extruder, and its process parameters are: set temperature 115℃, screw speed 65r / min, and extrusion time 11min;

[0049] The liquid diversion layer 3 includes radial wells connected to the drainage ditch and water storage tank via conduits, and longitudinal blind pipes set along the mine pit boundary. Several longitudinal blind pipes are each connected to the main blind pipe, and the end of the main blind pipe is connected to the drainage ditch and water storage tank along the slope. The anti-backflow pressure relief well and radial wells are all made of reinforced concrete. The radial wells are 22.5m deep, with each layer overlapping by 12.5m. Two are set per layer below +20m elevation, and one is set per layer above +20m elevation. The top elevation of the well is +50m.

[0050] The sludge filler layer 4 is filled with a mixture of industrial solid waste and functional fillers in equal mass ratios; the design elevation of the sludge filler layer 4 is +62.5m; the industrial solid waste used is Class I industrial solid waste;

[0051] The functional filler comprises, by weight percentage: 35% bentonite, 10% dehydrated aluminum salt, 2% water, 15% aggregate, 4% antifreeze agent, and the balance cement.

[0052] The dehydrated aluminum salt is composed of aluminum sulfate, aluminum chloride, potassium aluminum sulfate, and ferric chloride in a mass ratio of 1.5:2.5:1:1.

[0053] The aggregate is sea sand; the aggregate has two particle sizes, namely 50-55 mesh and 80-85 mesh, and the ratio of the two particle sizes is 2.5:1.

[0054] The antifreeze is a mixture of calcium chloride, magnesium chloride, and sodium chloride in a mass ratio of 2:1:1;

[0055] The cement is selected by mixing equal mass proportions of PII42.5 Portland cement, PC32.5 cement, P.O42.5R ordinary Portland cement, and low-alkalinity sulfoaluminate cement with a strength grade of 42.5.

[0056] The sealing topsoil layer 5 includes a clay layer with a thickness of 850 mm covering the upper surface of the sludge filler layer 4, and a topsoil layer with a thickness of 1200 mm covering the upper surface of the clay.

[0057] This embodiment of a method for remediating abandoned mines based on titanium gypsum includes the following steps:

[0058] S1. First, a drainage and pressure relief layer is laid in the mine pit for drainage and pressure relief. The drainage and pressure relief method is as follows: the groundwater is pumped into the anti-backflow pressure relief well using a pump body, the accumulated water is dispersed using radial drainage blind pipes, drainage ditches and water storage tanks are set at intervals outside the mine pit, the slope of the pit is reinforced, and the accumulated water at the bottom of the mine pit is drained.

[0059] S2. Lay an impermeable lining on the drainage and pressure relief layer: Evenly lay the bottom lining inside the mine pit, spray a 4.5mm thick polyurea coating on the bottom lining, then lay a polyurethane waterproof layer on the bottom lining, and then lay an impermeable material with a thickness of 1000mm on the polyurethane waterproof layer.

[0060] S3. Lay a liquid diversion layer on the seepage-proof lining: Set up several radial wells on the side of the mine pit, and connect the drainage ditch and water storage tank to the radial wells through conduits. Set up several longitudinal blind pipes along the boundary of the mine pit, and connect the longitudinal blind pipes to the main blind pipe. The end of the main blind pipe is connected to the drainage ditch and water storage tank along the slope. After collecting the leachate through the longitudinal blind pipes, it is introduced into the main blind pipe and sent into the drainage ditch and water storage tank. Excess water is introduced into the radial wells through conduits.

[0061] S4. Industrial solid waste and functional fillers are mixed in equal mass ratios to obtain sludge filler, and the sludge filler is laid on the liquid guide layer to form a sludge filler layer.

[0062] S5. Lay a clay layer with a thickness of 850mm on the sludge filler layer, and then cover the clay layer with a topsoil layer with a thickness of 1200mm to form a sealing topsoil layer.

[0063] Example 2

[0064] The difference between this embodiment and Embodiment 1 is that the bottom liner 21 is coated with a polyurea coating with a thickness of 6mm.

[0065] Example 3

[0066] The difference between this embodiment and Embodiment 1 is that the bottom liner 21 is coated with a polyurea coating with a thickness of 3mm.

[0067] Example 4

[0068] The difference between this embodiment and Embodiment 1 is that the filling compactness of the impermeable material is controlled to be 98%; and the laying thickness of the impermeable material is 1500mm.

[0069] Example 5

[0070] The difference between this embodiment and Embodiment 1 is that the filling compactness of the impermeable material is controlled to be 93%; and the laying thickness of the impermeable material is 500mm.

[0071] Example 6

[0072] The difference between this embodiment and Embodiment 1 is that the extruder used in the preparation method of the composite montmorillonite powder is a screw extruder, and its process parameters are: set temperature 120℃, screw speed 85r / min, and extrusion time 12min.

[0073] Example 7

[0074] The difference between this embodiment and Embodiment 1 is that the extruder used in the preparation method of the composite montmorillonite powder is a screw extruder, and its process parameters are: set temperature 110℃, screw speed 45r / min, and extrusion time 10min.

[0075] Example 8

[0076] The difference between this embodiment and Embodiment 1 is that, by mass percentage, 90% titanium gypsum, 5% composite montmorillonite powder, 2% silica powder, and the remainder zeolite powder are mixed to obtain the impermeable material.

[0077] Example 9

[0078] The difference between this embodiment and Embodiment 1 is that, by mass percentage, 80% titanium gypsum, 3% composite montmorillonite powder, 1% silica powder, and the remainder zeolite powder are mixed to obtain the impermeable material.

[0079] Example 10

[0080] The difference between this embodiment and Embodiment 1 is that the montmorillonite is pulverized, and by mass percentage, 80% of the montmorillonite powder, 1.5% of the hexadecyltrimethylammonium bromide, and the remainder of the polymeric surfactant are taken, mixed evenly, and then fed into an extruder for extrusion processing. After pulverization, composite montmorillonite powder is obtained.

[0081] Example 11

[0082] The difference between this embodiment and Embodiment 1 is that the montmorillonite is pulverized, and by mass percentage, 70% of the montmorillonite powder, 0.5% of the hexadecyltrimethylammonium bromide, and the remainder of the polymeric surfactant are taken, mixed evenly, and then fed into an extruder for extrusion processing. After pulverization, composite montmorillonite powder is obtained.

[0083] Example 12

[0084] The difference between this embodiment and embodiment 1 is that the depth of the radial well is 25m, each layer overlaps by 15m, and the design elevation of the slurry filler layer 4 is +75m.

[0085] Example 13

[0086] The difference between this embodiment and embodiment 1 is that the depth of the radial well is 20m, each layer overlaps by 10m, and the design elevation of the slurry filler layer 4 is +50m.

[0087] Example 14

[0088] The difference between this embodiment and Embodiment 1 is that the functional filler, by mass percentage, comprises: 40% bentonite, 15% dehydrated aluminum salt, 3% water, 20% aggregate, 5% antifreeze agent, and the balance cement.

[0089] Example 15

[0090] The difference between this embodiment and Embodiment 1 is that the functional filler, by mass percentage, comprises: 30% bentonite, 5% dehydrated aluminum salt, 1% water, 10% aggregate, 3% antifreeze agent, and the balance cement.

[0091] Example 16

[0092] The difference between this embodiment and Embodiment 1 is that the dehydrated aluminum salt uses aluminum sulfate, aluminum chloride, potassium aluminum sulfate, and ferric chloride in a mass ratio of 2:3:1:1.

[0093] Example 17

[0094] The difference between this embodiment and Embodiment 1 is that the dehydrated aluminum salt uses aluminum sulfate, aluminum chloride, potassium aluminum sulfate, and ferric chloride in a mass ratio of 1:2:1:1.

[0095] Example 18

[0096] The difference between this embodiment and Embodiment 1 is that the dehydrated aluminum salt is a dehydrated crystalline salt of aluminum chloride, and the aggregate is river sand; the aggregate has two particle sizes, namely 50-55 mesh and 80-85 mesh, and the ratio of the two particle sizes is 3:1.

[0097] Example 19

[0098] The difference between this embodiment and Embodiment 1 is that the aggregate used is river sand; the aggregate has two particle sizes, namely 50-70 mesh and 80-130 mesh, and the ratio of the two particle sizes is 2:1.

[0099] Example 20

[0100] The difference between this embodiment and Embodiment 1 is that the antifreeze is a mixture of calcium chloride, magnesium chloride, and sodium chloride in a mass ratio of 3:1:1.

[0101] Example 21

[0102] The difference between this embodiment and Embodiment 1 is that the antifreeze is a mixture of calcium chloride, magnesium chloride, and sodium chloride in a mass ratio of 1:1:1.

[0103] Example 22

[0104] The difference between this embodiment and Embodiment 1 is that the cement used is PII42.5 silicate cement and PC32.5 cement in equal mass ratio.

[0105] Example 23

[0106] The difference between this embodiment and Embodiment 1 is that the cement used is PII42.5 silicate cement and P.O42.5R ordinary silicate cement in equal mass ratio.

[0107] Example 24

[0108] The difference between this embodiment and Embodiment 1 is that the sealing topsoil layer 5 includes a clay layer with a thickness of 1500mm covering the upper surface of the sludge filler layer 4, and a topsoil layer with a thickness of 2000mm covering the upper surface of the clay.

[0109] Example 25

[0110] The difference between this embodiment and Embodiment 1 is that the sealing topsoil layer 5 includes a 200mm thick layer of clay covering the upper surface of the sludge filler layer 4, and a 400mm thick layer of topsoil covering the upper surface of the clay.

[0111] Application example:

[0112] The radiation-proof fabric was tested for its performance in abandoned mine restoration using the methods described in Examples 1, 8-11, 14, 15, 24, 25 and Comparative Example 1. Fourteen equally sized areas were divided, and after one year of restoration, the soil was tested for heavy metals. The difference between Comparative Example 1 and Example 1 is that the impermeable lining used commercially available clay as the impermeable material. The selected data results are shown in Table 1 below.

[0113] Table 1: Performance Test Table of Abandoned Mine Restoration in Examples 1, 8-11, 14, 15, 24, 25 and Comparative Example 1

[0114]

[0115]

[0116] The titanium gypsum samples used in Examples 1-3, 6-15, 24, and 25 were selected for analysis, and the organic matter content ranged from 0.01% to 1.88%. The data results are shown in Table 2 below.

[0117] Table 2: Results of Organic Matter Content Analysis of Titanium Gypsum

[0118]

[0119] 1. Investigate the influence of the formulation parameters of the impermeable material on the remediation performance of abandoned mines:

[0120] As shown in Table 1, different proportions of the impermeable material have a certain impact on the remediation performance of abandoned mines. Comparing Example 1 and Comparative Example 1, Example 1 has the best remediation effect. As shown in Table 2, the titanium gypsum has a better organic matter content, which can not only achieve impermeability but also benefit mine remediation.

[0121] Compared with Examples 8 and 9, Example 8 showed the best repair performance.

[0122] 2. Investigating the effects of the formulation parameters of the composite montmorillonite powder on the remediation performance of abandoned mines:

[0123] As shown in Table 1, the ratio of composite montmorillonite powder has a certain impact on the remediation performance of abandoned mines. Comparing Examples 1, 10, and 11, Example 1 has the best remediation performance.

[0124] 3. Investigate the influence of the formulation parameters of the functional filler on the remediation performance of abandoned mines:

[0125] As shown in Table 1, there is no significant difference in the results between Example 1 and Examples 14 and 15, and Example 1 has the best repair performance.

[0126] 4. Investigate the impact of five process parameters for laying the topsoil layer on the remediation performance of abandoned mines:

[0127] As shown in Table 1, compared with Examples 24 and 25, the process parameters for laying the topsoil layer 5 have a certain impact on the restoration performance of abandoned mines, and Example 1 has the best restoration performance.

Claims

1. A structure for the remediation of abandoned mines based on titanium gypsum, characterized in that, It consists of a drainage and pressure relief layer (1), an anti-seepage lining layer (2), a liquid diversion layer (3), a sludge filling layer (4), and a sealing topsoil layer (5), arranged sequentially from bottom to top in the mine pit; The drainage and pressure relief layer (1) includes multiple anti-backflow pressure relief wells and radial drainage blind trenches connected to the anti-backflow pressure relief wells; The impermeable lining (2) includes a bottom lining sheet (21), a polyurethane waterproof layer (22) disposed on the bottom lining sheet (21), and an impermeable material laid on the polyurethane waterproof layer (22); the bottom lining sheet (21) is sprayed with a polyurea coating with a thickness of 3~6mm; the bottom lining sheet (21) is made of stainless steel; the filling compactness of the impermeable material is controlled to be 93~98%; The thickness of the impermeable material is 500~1500mm. The preparation method is as follows: by mass percentage, 80~90% titanium gypsum, 3~5% composite montmorillonite powder, 1~2% silica powder and the balance zeolite powder are mixed to obtain the impermeable material. The preparation method of the composite montmorillonite powder is as follows: montmorillonite is crushed, and 70-80% of montmorillonite powder, 0.5-1.5% of hexadecyltrimethylammonium bromide, and the remainder of high molecular weight surfactant are taken by mass percentage, mixed evenly, and then put into an extruder for extrusion treatment. After crushing, composite montmorillonite powder is obtained. The extruder used in the preparation method of the composite montmorillonite powder is a screw extruder, and its process parameters are: set temperature 110~120℃, screw speed 45~85r / min, and extrusion time 10~12min; The liquid guiding layer (3) includes a radial well connected to a drainage ditch and a water storage tank via a conduit, and a longitudinal blind pipe set along the boundary of the mine pit. Several longitudinal blind pipes are connected to the main blind pipe, and the end of the main blind pipe is connected to the drainage ditch and the water storage tank along the slope. The sludge filler layer (4) is filled with a mixture of industrial solid waste and functional fillers in equal mass proportions; The sealing topsoil layer (5) includes a clay layer with a thickness of 200-1500 mm covering the upper surface of the sludge filler layer (4), and a topsoil layer with a thickness of 400-2000 mm covering the upper surface of the clay.

2. The abandoned mine restoration structure based on titanium gypsum as described in claim 1, characterized in that, The backflow prevention and pressure relief wells and radial wells are all made of reinforced concrete.

3. The abandoned mine restoration structure based on titanium gypsum as described in claim 1, characterized in that, The functional filler comprises, by mass percentage: 30-40% bentonite, 5-15% dehydrated aluminum salt, 1-3% water, 10-20% aggregate, 3-5% antifreeze agent, and the balance cement.

4. The abandoned mine restoration structure based on titanium gypsum as described in claim 3, characterized in that, The dehydrated aluminum salt is made of aluminum sulfate, aluminum chloride, potassium aluminum sulfate and ferric chloride in a mass ratio of 1~2:2~3:1:1, or a dehydrated crystalline salt of aluminum chloride, or a dehydrated crystalline salt of ferric sulfate, aluminum chloride and aluminum sulfate in an equal mass ratio.

5. The abandoned mine restoration structure based on titanium gypsum as described in claim 3, characterized in that, The aggregate is any one or a combination of two or more of the following: sea sand, river sand, stone powder, mineral sand, and quartz sand; the aggregate has two particle sizes, namely 50-70 mesh and 80-130 mesh, and the ratio of the two particle sizes is 2-3:

1.

6. The abandoned mine restoration structure based on titanium gypsum as described in claim 3, characterized in that, The antifreeze is a mixture of calcium chloride, magnesium chloride, and sodium chloride in a mass ratio of 1~3:1:1; The cement is selected from any one or more of the following: PII42.5 silicate cement, PC32.5 cement, P.O42.5R ordinary silicate cement, and low-alkalinity sulfoaluminate cement with a strength grade of 42.

5.

7. A method for remediating abandoned mines based on titanium gypsum, using the remediation structure described in any one of claims 1-6, characterized in that, Includes the following steps: S1. First, a drainage and pressure relief layer (1) is laid in the mine pit for drainage and pressure relief. The drainage and pressure relief method is as follows: the groundwater is discharged into the anti-backflow pressure relief well by a pump body, the accumulated water is dispersed by radial drainage blind pipes, drainage ditches and water storage tanks are set at intervals outside the mine pit, the slope of the pit is reinforced, and the accumulated water at the bottom of the mine pit is drained. S2. Lay a seepage-proof lining (2) on the drainage and pressure relief layer (1): evenly lay the bottom lining (21) inside the mine pit, spray a polyurea coating with a thickness of 3~6mm on the bottom lining (21), then lay a polyurethane waterproof layer (22) on the bottom lining (21), and then lay a seepage-proof material with a thickness of 500~1500mm on the polyurethane waterproof layer (22). S3. Lay a liquid guiding layer (3) on the seepage-proof lining (2): Set up several radial wells on the side of the mine pit, and connect the drainage ditch and water storage tank to the radial wells through the guide pipe. Set up several longitudinal blind pipes along the boundary inside the mine pit, and connect the several longitudinal blind pipes to the main blind pipe respectively. The end of the main blind pipe is connected to the drainage ditch and water storage tank along the slope. After collecting the leachate through the longitudinal blind pipes, it is introduced into the main blind pipe and sent into the drainage ditch and water storage tank. Excess water is introduced into the radial well through the guide pipe. S4. Industrial solid waste and functional fillers are mixed in equal mass ratio to obtain sludge filler, and the sludge filler is laid on the liquid guide layer (3) to form a sludge filler layer (4). S5. Lay a clay layer with a thickness of 200~1500mm on the sludge filler layer (4), and then cover the clay layer with a topsoil layer with a thickness of 400~2000mm to form the sealing topsoil layer (5).

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