Waste mine pit resource utilization mining method based on sludge solidification

Abstract

The invention provides a waste mine pit resource utilization mining method based on sludge solidification, and relates to the technical field of mine exploitation and resource recovery, and the method comprises the steps of sludge and water body composition analysis, layered water body extraction, wastewater heavy metal treatment, multi-stage filtration and centrifugal separation, solidified body putting and gradual slow release, multi-stage stirring, and layered exploitation. And waste rock and tailings are backfilled. According to the method, environment-friendly treatment and resource mining of the waste mine pit sludge are effectively achieved, environmental pollution is reduced, the recovery rate of mineral resources is increased, and good economic and social benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of mining and resource recovery, and in particular to a mining method for resource utilization of abandoned mines based on sludge solidification. Background Art

[0002] With the continuous advancement of mining activities, the number of abandoned mines is increasing. These mines often accumulate a large amount of silt and water, which creates an environmental burden and wastes resources. The silt in abandoned mines is usually rich in mineral components, but due to its high water content and unstable structure, it is difficult to effectively extract the minerals in it through traditional dredging and resource recovery methods. In addition, the water in the silt can easily lead to mud loss, resulting in low utilization of curing agents and minerals during curing and mining, causing serious environmental problems and resource losses.

[0003] Current sludge treatment methods are mainly concentrated in the fields of soil solidification and sludge dehydration, and usually use pumping, sedimentation, landfill and other methods for preliminary treatment. However, these methods often lack systematic resource recovery methods, especially for sludge containing valuable minerals, traditional treatment methods cannot achieve its resource mining. At the same time, problems such as uneven penetration of curing agents and difficulty in controlling release during the solidification process also affect the treatment effect, making it difficult to improve the resource utilization rate of the mine. In addition, wastewater treatment and water resource waste in the process of abandoned mine treatment are also an environmental protection problem that needs to be solved urgently.

[0004] Therefore, in response to the solidification and resource-based mining needs of abandoned mine sludge, a systematic and environmentally friendly treatment method is urgently needed to achieve layered solidification, layer-by-layer mining and waste recycling of sludge, which can not only improve the recovery efficiency of mineral resources, but also effectively reduce the impact of the treatment process on the environment, and meet the requirements of modern mining area environmental governance and sustainable resource development. Summary of the invention

[0005] The present invention provides a mining method for resource utilization of abandoned mines based on sludge solidification, aiming to solve the problems of difficulty in recovering mineral resources, poor solidification effect, waste of water resources and environmental pollution in the existing abandoned mine treatment process. Through systematic sludge treatment and layer-by-layer mining process, efficient utilization of mineral resources and environmentally friendly restoration of abandoned mines can be achieved.

[0006] The present invention provides a mining method for resource utilization of abandoned mines based on sludge solidification, comprising the following steps:

[0007] S1. Take samples of sludge and water in abandoned mines, measure the thickness of sludge layer and accumulated water, and analyze the mineral composition;

[0008] S2, extract the water from the upper surface of the sludge layer by layer, and each extraction is carried out when the water body returns to a stable state after the previous pumping disturbance;

[0009] S3, placing the extracted water into a wastewater pool, adding adsorbent to remove heavy metals in the water; after the heavy metal content in the wastewater reaches the standard after sedimentation, the upper wastewater is discharged;

[0010] S4. Use a pump equipped with a multi-stage filtration device to extract water from the sludge layer by layer, and use a moisture sensor to monitor the moisture content of the sludge in real time;

[0011] S5, adding a curing agent into the sludge layer;

[0012] S6. Use a multi-stage mixing device equipped with a drill bit to mix the silt layer;

[0013] S7. After the sludge is completely solidified, the sludge is mined directly from the surface using a top-down layered mining method, and the waste rock and tailings generated during the mining process are collected;

[0014] S8 The waste rock, tailings, cementitious materials and waste water generated during the mining process are filled into the mining pit.

[0015] Preferably, the adsorbent in S3 is at least selected from lime.

[0016] Preferably, S4 also includes: the water extracted by the water pump is further centrifuged, the liquid phase after centrifugal separation enters the wastewater pool, and the solid phase is used for mineral recovery; the water pump is selected from a submerged slag pump and / or a slurry pump; the water pump also has a filter screen according to the composition of the sludge; in the present invention, the water pump selects filter screens of different specifications according to the composition of the sludge, and combines centrifugal separation technology to extract water from the sludge to retain the solid components for mineral extraction; the height of extracting water from the sludge layer by layer is 4-5 meters, and when the water content sensor measures the water content in the sludge to be 65%-70%, the extraction of the next layer begins.

[0017] Preferably, S5 also includes: the selection of the curing agent is based on the mineral composition; the curing agent is processed into particles with a three-layer structure, with gelatin between each layer, ensuring that the first layer is fully released within the first day, the second layer is released from the second to third days, and the third layer is released from the fourth to sixth days.

[0018] The curing agent in the present invention is divided into three layers from the outside to the inside. The first layer is a quick-release layer, the main purpose of which is to quickly reduce the moisture content of the sludge, start the curing process, and seal the heavy metal ions in the water. The ingredients are calcium chloride (inorganic salt), bentonite (adsorbent) and aluminum sulfate (accelerator) (calcium chloride: 50-60wt%, bentonite: 20-30wt%, aluminum sulfate: 10-20wt%); the second layer is a medium-speed release layer, which mainly uses a more stable and slow-release curing agent to gradually strengthen the curing effect, and further stabilize the sealed heavy metals, while enhancing the mechanical strength of the cured body. The ingredients are cement (cementitious material), calcium phosphate (seals heavy metals) and sodium silicate (waterproofing agent) (cement: 4 5-50wt%, calcium phosphate: 30-35wt%, sodium silicate: 15-20wt%); the third layer is a slow release layer, which is mainly used for the final reinforcement and long-term stable heavy metal sealing. The ingredients are volcanic ash and / or fly ash (to extend the reaction time of the curing agent and provide a lasting reinforcement effect), sodium silicate (waterproofing agent) and calcium sulfate (slowly releasing hydrate) (volcanic ash: 40-50wt%, fly ash: 30-40wt%, sodium silicate: 5-10wt%, calcium sulfate: 5-10wt%).

[0019] The first layer is released quickly, with the purpose of quickly absorbing water, adsorbing heavy metals, and quickly accelerating the curing process. At this time, the curing agent needs to have a strong reaction ability to quickly consume the water in the sludge and start curing.

[0020] The second layer releases more slowly, focusing on strengthening the structure and maintaining control of moisture and heavy metals. The curing process is still ongoing, but the release rate is slowed down to ensure that the cured body gradually stabilizes.

[0021] The third layer is gradually released over a long period of time. This layer is responsible for long-term sealing, maintaining the overall stability of the solidified body, and preventing moisture and pollutants from penetrating into the solidified layer again, thereby avoiding the re-release of heavy metals.

[0022] The amount of curing agent added is based on the moisture content, which is 3%-5% of the sludge.

[0023] The three-layer slow-release curing agent design can ensure the gradual release of the curing agent in the sludge, thereby achieving a more uniform and effective curing process and adapting to the different curing requirements of the sludge. The curing process of the sludge is gradual. If all the curing agent is released at one time, it may lead to over-curing or too fast reaction, which will affect the curing effect. The three-layer slow-release design can ensure that the curing agent is continuously released at different time stages, adapt to the curing requirements at different stages, and make the whole process more uniform. In addition, the slow release rate can make the chemical reaction between the curing agent and the sludge proceed for a long time, and there will be no problem of local overreaction caused by early release too fast, which enhances the durability of the curing effect. The three-layer slow-release design controls the release rate of the curing agent so that the curing process can be completed step by step according to the different parts and depth requirements of the sludge, avoiding the situation where the surface hardens prematurely while the interior is not fully cured. In addition, in some cases, if the curing agent is released all at once, it may cause waste of curing agent due to the dilution effect of water or the incomplete curing of part of the sludge. Through layered slow release, the curing agent can be released on demand, improving its utilization rate and avoiding unnecessary waste.

[0024] Preferably, S6 also includes: a drill bit is provided at the front end of the stirring device, and a stirring level is designed every 4 to 5 meters according to the thickness of the sludge layer to form a multi-stage stirring structure; from top to bottom of the entire stirring device, the diameter of the stirring paddle blades gradually decreases, and the rotation speed of the stirring paddle gradually increases.

[0025] Preferably, S7 also includes: using equipment with less disturbance, such as an excavator, when excavating the upper layer of solidified sludge, and using equipment with greater disturbance, such as rock drilling and blasting, to complete mineral excavation when excavating the lower layer of solidified sludge.

[0026] Preferably, the wastewater in S8 is selected from wastewater discharged from a wastewater pond.

[0027] The beneficial effects brought about by the technical solution provided by the present invention include at least:

[0028] (1) Improve the recovery rate of mineral resources. The present invention can effectively extract the mineral components contained in the sludge by systematically layering and solidifying the sludge, avoiding the loss of mineral resources in traditional sludge treatment methods and greatly improving the mineral recovery rate.

[0029] (2) Improved curing effect and structural stability. The present invention uses a specific curing agent and achieves uniform curing through multi-stage slow release and layered stirring. The multi-stage design of the stirring equipment ensures uniform distribution of the curing agent at different levels, making the structure of the sludge layer more stable after curing, which is convenient for subsequent mining operations.

[0030] (3) Reduce environmental pollution and improve water resource utilization. The present invention can effectively remove heavy metals from water bodies through the use of heavy metal adsorbents and multi-stage wastewater treatment, so that the discharged water meets environmental protection standards and reduces heavy metal pollution in mining areas. In addition, after the heavy metals are removed from the wastewater generated during the treatment process, it can be reused for mixing cementitious materials and backfilling pits, thus realizing the recycling of water resources.

[0031] (4) Reduce the energy and material costs of sludge treatment. Through layered pumping and multi-stage filtration, the moisture content of the sludge is reduced layer by layer, avoiding high-temperature drying or excessive mechanical dehydration that consumes a lot of energy, and significantly reducing the treatment cost. At the same time, the components of the curing agent are made of alternative materials such as volcanic ash and fly ash, which further saves resources and improves the cost-effectiveness of the curing agent.

[0032] (5) Improve the safety and environmental protection of the mining process. The present invention adopts a layer-by-layer pumping and layered mining method, which effectively reduces the safety hazards caused by sludge instability during the mining process. In addition, the waste rock and tailings generated by mining are mixed with cementitious materials and wastewater and backfilled into the mining pit, which reduces the environmental impact caused by the transportation and accumulation of mining waste, and ensures the ecological restoration of the mining area.

[0033] (6) Promote sustainable development of mining areas. The systematic treatment method of the present invention can not only effectively recover mineral resources, but also realize the resource utilization of mining waste and the ecological restoration of mining pits, which is helpful to build green mines and promote sustainable development and environmental protection of mining areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of 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 creative work.

[0035] Figure 1 is a flow chart of the method of the present invention;

[0036] Figure 2 This is a contour map of the silt layer thickness distribution of Example 1 of the present invention. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is described below.

[0038] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0039] In the embodiments of the present invention, sometimes a subscript such as W1 may be mistakenly written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are consistent.

[0040] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0041] The present invention provides a mining method for resource utilization of abandoned mines based on sludge solidification, which realizes stable solidification of sludge in abandoned mines and efficient recovery of mineral resources through systematic sludge treatment, layered water extraction, heavy metal removal, graded mining and waste filling. The specific process is as follows: Figure 1 As shown, the following steps are included:

[0042] S1 Analysis of the composition of sludge and water. Sampling and analysis of sludge and water in abandoned mines, using sonar technology to measure the thickness of the sludge layer and the water layer, and conducting mineral composition analysis. Special attention is paid to the metal mineral components contained in the sludge and the heavy metal content in the water, providing data support for subsequent treatment processes.

[0043] The present invention determines the basic conditions of water and sludge in the mine through preliminary analysis of sludge and water, and provides a basis for the selection of curing agent and adsorbent and the design of treatment process.

[0044] S2 Extract water in layers. Extract water from the upper surface of the sludge layer by layer, use a pump to let the water stand still after each extraction, and let the water return to a stable state before the next extraction, to ensure the stability of each layer of water and achieve the effect of layered extraction.

[0045] The layer-by-layer pumping method of the present invention can avoid the disturbance of the silt layer structure caused by large-scale pumping, maintain the stability of each layer of silt in the mine, and facilitate subsequent solidification and layered mining operations.

[0046] S3 Wastewater heavy metal treatment. The extracted water is placed in a wastewater pool, and adsorbents such as lime are added to remove heavy metals in the water. Insoluble precipitates are generated by the adsorbents and heavy metal ions in the water to form a sludge layer. After the wastewater is allowed to settle, the heavy metal content in the upper layer of wastewater is measured and discharged only after it meets the discharge standards. The precipitate can be stored for future use and further used in the S8 step as a filling material for the mine.

[0047] The present invention ensures the environmentally friendly discharge of wastewater by absorbing heavy metals, avoids heavy metal pollution of the surrounding environment, and at the same time recycles the sediment as a resource, reducing the amount of waste to be processed.

[0048] S4 Multi-stage filtration and centrifugal separation. According to the particle size and moisture content of the sludge, select the appropriate filter screen, and combine with centrifugal separation technology to extract the moisture in the sludge layer by layer. The depth of each pumping is controlled at 4-5 meters, and the moisture content is monitored in real time. When the moisture content drops to 65%-70%, the next layer is extracted. The wastewater after centrifugal separation enters the wastewater pool again, and the separated solid minerals enter the mineral recovery process.

[0049] The multi-stage filtration and centrifugal separation of the present invention can effectively reduce the moisture content of the sludge, retain mineral particles, reduce the interference of water on the subsequent solidification effect, and improve the recovery rate of mineral resources. In view of the fact that it is time-consuming and labor-intensive to directly drain the sludge, and the solidification effect is poor, which is not enough to support later mining, the scheme of initial draining and using a curing agent is selected. In addition, considering the reasons such as saving electricity used for extracting sludge, the requirements for initial dehydration of sludge, and facilitating the stirring of the later curing agent, a layered pumping design with a moisture content of 65%-70% is selected. When too much water is extracted, the sludge will be greatly disturbed, which may cause the instability of the sludge layer or excessive dilution. If the depth of each pumping is controlled at 4-5 meters, it can avoid excessive pumping at one time, thereby reducing the risk of disturbance of the sludge layer. In this way, the water extraction process of each layer can be ensured to be relatively stable, ensuring the stability of the sludge layer. And the depth of each pumping is maintained at 4-5 meters, which can make the operation more controllable. Compared with pumping at great depths, gradual, layered pumping is easier to adjust during construction and can detect potential problems in a timely manner, avoiding unnecessary operational errors caused by excessive depth.

[0050] S5 Curing agent delivery and gradual release. Curing agent is delivered to the sludge layer. The composition of the curing agent is selected according to the mineral types in the sludge. If necessary, volcanic ash or fly ash can be added for resource utilization. The curing agent adopts a three-layer structure design, and each layer is separated by gelatin. The first layer is released within one day, the second layer is released from the second to third day, and the third layer is slowly released from the fourth to sixth day.

[0051] The gradual slow release design of the curing agent of the present invention can ensure the stability and durability of the curing process, enhance the curing effect, gradually improve the strength of the sludge layer, and avoid uneven curing or insufficient strength caused by rapid release of the curing agent. The present invention uses a curing agent to convert liquid sludge into a firm and stable solid structure through a chemical reaction, providing convenience for subsequent mining processes, avoiding pit collapse or fragmentation, and maintaining its curing effect for a long time to meet the requirements of long-term mining.

[0052] S6 Multi-stage mixing. The sludge layer is mixed using a multi-stage mixing device equipped with a drill. The mixing levels are designed according to the thickness of the sludge layer, usually every 4 to 5 meters. The design of the mixing paddle gradually reduces the blade diameter from top to bottom and gradually increases the speed to ensure uniform distribution of the curing agent at different depths and enhance the mixing effect. The drill bit can be used to loosen the sludge to allow the curing agent to fully penetrate.

[0053] The multi-stage mixing design of the present invention can ensure the uniform distribution of the curing agent, prevent the curing effect at different depths from being inconsistent, thereby affecting the layout of mining equipment, and the excellent multi-layer curing effect of multi-stage mixing will directly serve the later stratified mining. The drill bit assists in breaking and loosening the silt structure, making it easier for the curing agent to penetrate into the deep silt and improve the curing strength.

[0054] S7 Layered mining. After the silt layer is completely solidified, the top-down layered mining method is adopted. For the shallow layer, light equipment such as excavators are used to prevent excessive disturbance of the solidified layer; in the deep layer, drilling rigs or blasting are used to complete mineral extraction. The waste rock and tailings generated during the mining process are collected for subsequent backfilling and resource utilization.

[0055] In order to avoid the collapse of the silt layer caused by dynamic disturbance, the present invention adopts layered mining, which not only protects the stability of the ore body structure and ensures that the solidified layer is not damaged during the mining process, but also can extract mineral resources at different levels in stages, further improving the resource recovery efficiency.

[0056] S8 Backfilling of waste rock and tailings. The waste rock and tailings collected during the mining process are mixed with cementitious materials and treated wastewater to make filling materials and backfill them into the mining pit. This step uses waste materials to fill the mining pit, avoids tailings accumulation, and further stabilizes the mining pit structure to achieve ecological restoration of the mining area.

[0057] The present invention utilizes waste materials for backfilling, which, on the one hand, reduces the demand for transporting solid waste, reduces environmental pollution, and realizes the internal circulation of solid waste in abandoned mines; on the other hand, it restores the mining pit to a stable state, ensuring the safety of the mining area.

[0058] The following is a further detailed description of the mining method for resource utilization of abandoned mines based on sludge solidification described in the present invention through a specific example.

[0059] Example 1

[0060] Take a mine in the Democratic Republic of the Congo as an example. The ore body began to be developed around the 1940s. By the 1960s and 1980s, the shallow high-grade oxide ore resources were basically exhausted and the open pit mining was stopped. However, combined with the existing exploration results, it is estimated that the total amount of resources is 1,955,455 tons, the amount of copper metal is 92,324 tons (average grade 4.72%), and the amount of cobalt metal is 5,550 tons (average grade 0.28%), which still has a high mining value. At present, the ore body mining pit has become a pond with water accumulation for many years, and a large amount of silt has accumulated at the bottom of the pit. The existence of these water bodies and silt seriously affects the development and utilization of deep resources. Whether it is open-pit or underground mining, it is inevitable to involve the drainage and dredging of the mining pit. Drainage and dredging have become an important prerequisite and key link for the resumption of mining in the mine.

[0061] The traditional dredging method is to drain the water from the pit, stir the sludge at the bottom of the pit into a slurry and pump it out, but there are many problems, including but not limited to:

[0062] (1) Since the sludge discharged from the pumping pipeline is in a liquefied state and its mechanical properties are similar to those of tailings, and the sludge contains minerals, it cannot be mixed with tailings. Therefore, a separate storage site that meets the requirements of a tailings pond must be built, which is equivalent to building a new independent tailings pond;

[0063] (2) After the expansion of the smelter is completed, the piled sludge needs to be removed for utilization. The drained and solidified sludge needs to be broken up, liquefied, and pumped again. The two dredging operations will incur huge unnecessary costs. According to incomplete estimates, it will cost at least US$10 million more.

[0064] In view of the above problems, the present invention provides a mining method for resource utilization of abandoned mines based on sludge solidification, which is applied to the dredging and mining of the abandoned mines, and the steps are as follows:

[0065] First, the silt and water in the abandoned mine were sampled and analyzed, and the thickness of the silt layer and accumulated water was measured using sonar technology. Figure 2 The thickness distribution contour map of the silt layer is shown. The water storage capacity is 3.444 million cubic meters, the silt volume is 1.955 million cubic meters, and the deepest part is over 20 meters.

[0066] According to the contour map of the silt layer thickness distribution, the extraction plan was determined. Three floating pump stations were used to extract water from the upper surface of the silt layer by layer at a depth of 10 meters. Each extraction was carried out every 24 to 48 hours. The extracted water was transported to the wastewater pool through a rubber hose. Lime was added to the wastewater pool to remove heavy metals in the water. The wastewater in the wastewater pool was sampled regularly for chemical composition measurement. After the heavy metal content in the wastewater reached the standard after sedimentation, the upper wastewater was discharged.

[0067] The submersible slag pump is used in series with the horizontal slurry pump. The submersible slag pump is placed in the sludge and suspended by a lifting device during dredging to ensure that the submersible slag pump is completely submerged in water at a depth of 4.5 to 5.0 meters. The horizontal slurry pump acts as a relay pump to discharge the mixed mud. The discharged solid-liquid mixture is centrifuged, and the solid component enters the mining site for metal refining, while the liquid component is discharged into the wastewater pool. The water content sensor is used to monitor the extraction process. When the water content reaches 65%-70%, the next layer of extraction begins.

[0068] After all the silt layers have been processed, a curing agent is added to the silt layer. Since the water content is low at this time, multi-layer slow-release volcanic ash and fly ash can be added to the curing agent. According to the silt contour map, a mixer equipped with a drill is used to drill into the bottom of the silt layer. A total of three mixing levels are designed. From top to bottom, the diameter of the stirring blade gradually decreases, and the speed of the stirring blade gradually increases to fully stir the mud and mix it evenly.

[0069] After the silt is completely solidified, the top-down stratified mining method is adopted to mine layer by layer from the surface of the silt. When excavating the upper solidified silt, equipment with less disturbance such as excavators is used; when excavating the lower solidified silt, equipment with greater disturbance such as rock drilling and blasting is used to complete the mining of deep minerals. During the mining process, waste rock and tailings are collected, and after the mining is completed, cement and fly ash are combined with wastewater to fill the mining pit.

[0070] According to statistics, a mine in the Democratic Republic of the Congo has recovered 118 tons of minerals in sludge by using this method, with a utilization rate of 84% and a cumulative profit of more than 8.4 million yuan. In addition, since there is no need to build a dump for storing sludge, the indirect costs obtained by shortening the construction period and saving equipment costs have exceeded 60 million yuan. In addition, the mine has utilized more than 200,000 tons of tailings, realizing the solid waste cycle in the mine pit and obtaining greater economic benefits.

[0071] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A mining method for resource utilization of abandoned mines based on sludge solidification, characterized in that the steps include: S1. Take samples of sludge and water in abandoned mines, measure the thickness of sludge layer and accumulated water, and analyze the mineral composition; S2, extract the water from the upper surface of the sludge layer by layer, and each extraction is carried out when the water body returns to a stable state after the previous pumping disturbance; S3, placing the extracted water into a wastewater pool, adding adsorbent to remove heavy metals in the water; after the heavy metal content in the wastewater reaches the standard after sedimentation, the upper wastewater is discharged; S4. Use a pump equipped with a multi-stage filtration device to extract water from the sludge layer by layer, and use a moisture sensor to monitor the moisture content of the sludge in real time; S5, adding a curing agent into the sludge layer; S6. Use a multi-stage mixing device equipped with a drill bit to mix the silt layer; S7. After the sludge is completely solidified, the sludge is mined directly from the surface using a top-down layered mining method, and the waste rock and tailings generated during the mining process are collected; S8 The waste rock, tailings, cementitious materials and waste water generated during the mining process are filled into the mining pit.

2. The method according to claim 1, characterized in that The adsorbent in S3 is at least selected from lime.

3. The method according to claim 1, characterized in that S4 also includes: the water pumped out by the water pump is further centrifuged, the liquid phase after centrifugal separation enters the wastewater pool, and the solid phase is used for mineral recovery.

4. The method according to claim 3, characterized in that: S4 also includes: the water pump is selected from a submersible slag pump and / or a slurry pump; the water pump also has a filter screen according to the composition of the sludge; the height of extracting water from the sludge layer by layer is 4-5 meters, and when the water content sensor measures the water content of the sludge to be 65%-70%, the extraction of the next layer begins.

5. The method according to claim 1, characterized in that: S5 also includes: selecting a curing agent based on mineral components; processing the curing agent into particles with a three-layer structure, with gelatin between each layer, wherein the first layer is completely released within the first day, the second layer is released from the second to third days, and the third layer is released from the fourth to sixth days.

6. The method according to claim 1, characterized in that The solidifying agent in S5 is added at 3wt%-5wt% of the sludge amount.

7. The method according to claim 5, characterized in that The first layer of the curing agent comprises calcium chloride, bentonite and aluminum sulfate; the second layer comprises cement, calcium phosphate and sodium silicate; and the third layer comprises volcanic ash and / or fly ash, sodium silicate and calcium sulfate.

8. The method according to claim 1, characterized in that S6 also includes: a drill bit is provided at the front end of the mixing equipment, and a mixing level is designed every 4 to 5 meters according to the thickness of the silt layer to form a multi-stage mixing structure; from top to bottom, the diameter of the mixing paddle blades gradually decreases, and the rotation speed of the mixing paddle gradually increases.

9. The method according to claim 1, characterized in that: S7 also includes: when excavating the upper layer of solidified sludge, equipment with less disturbance, such as excavators, is used; when excavating the lower layer of solidified sludge, equipment with greater disturbance, such as rock drilling and blasting, is used to complete mineral excavation.

10. The method according to claim 1, characterized in that The wastewater in S8 is selected from the wastewater discharged from the wastewater pool.

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