Method for pit backfilling and ecological restoration by using pyrite slag solid waste
By modifying and vegetation repairing the sulfide slag, it is converted into pit backfill and ecological restoration materials, the environmental pollution and resource utilization problems in sulfide slag treatment are solved, and the stability and ecological restoration effect of the mine are achieved.
Patent Information
- Application Number
- CN202510473410.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-16
- Publication Date
- 2025-07-08
AI Technical Summary
The treatment and utilization of sulfhydryl slag poses a risk of environmental pollution, and there is insufficient backfill materials for traditional mine pits, making it difficult to achieve effective ecological restoration and resource utilization.
By conducting environmental risk assessment and modification treatment of thioferite slag, it is converted into functional materials for pit backfill and ecological restoration, including crushing, screening, pH adjustment, organic matter addition and gelling material mixing, combining anti-seepage treatment and vegetation restoration, we ensure the stability of the backfill area and the ecological restoration effect.
It has realized the resource utilization of solid waste, reduced environmental pollution, improved regional environmental quality, reduced engineering costs, and ensured the long-term and stability of ecological restoration.
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Figure FT_1
Abstract
Description
Technical Field
[0001] The present invention relates to a method for using pyrite cinder solid waste for mine backfilling and ecological restoration, belonging to the technical field of mining solid waste treatment and ecological restoration. Background Art
[0002] Pyrite cinder is a solid waste generated during the mining and smelting of pyrite. Its main components are elements such as iron, sulfur, silicon, and aluminum, and it also contains a small amount of heavy metals (such as cadmium, lead, zinc, etc.). Due to its complex chemical composition and harmful substances, traditional treatment methods are mostly open-air stacking, landfilling, or using as auxiliary materials for building materials. This not only occupies a large amount of land resources but also may cause serious pollution to the surrounding environment. For example, the sulfur element in pyrite cinder is easily oxidized to sulfuric acid under natural conditions, resulting in soil acidification, which in turn affects plant growth and soil microbial activity. In addition, the heavy metal elements in pyrite cinder may seep into groundwater or surface water under the scouring of rainwater, causing water pollution and threatening the ecosystem and human health.
[0003] A mine pit is a huge cavity left after the mining of mineral resources. Its existence not only destroys the surface landscape but also may trigger geological disasters (such as collapses, landslides, etc.). Mine backfilling can play a role in slope reduction and foot pressure, and is also an important measure to ensure slope stability. Traditional mine backfilling materials can use natural earth and rock or mine waste rock, which have problems such as insufficient volume, difficult material extraction, and high costs. Therefore, it is of great significance to develop a method that can not only achieve mine backfilling but also carry out ecological restoration.
[0004] In recent years, with the increasingly strict environmental protection requirements and the progress of resource utilization technologies, the comprehensive utilization of pyrite cinder has become a research hotspot. Pyrite cinder generally belongs to the second-class solid waste. In the existing technology, it is mainly used in fields such as building materials, roadbed filling, or cement admixtures. However, with the market fluctuations in related industries such as construction, the demand for building materials and the like has decreased sharply, resulting in problems such as difficult consumption of solid waste stocks and low efficiency. And in the field of mine treatment and ecological restoration, there are a large number of earthwork volume requirements that are difficult to solve. As a large amount of solid waste, pyrite cinder can be used as a mine backfilling material and ensure slope stability. Moreover, pyrite cinder is rich in elements such as iron and silicon, and has the potential to improve soil, adsorb pollutants, and promote plant growth to a certain extent. Therefore, the present invention establishes a method for using pyrite cinder for mine backfilling and ecological restoration, which can not only realize the resource utilization of solid waste but also provide a new solution for the treatment of mine geological environment. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide a method for using pyrite slag solid waste for mine pit backfilling and ecological restoration. This restoration method conducts an environmental risk assessment and modification treatment on the pyrite slag to enable it to have the dual functions of mine pit backfilling and ecological restoration. By crushing, screening, and modifying the pyrite slag, it is transformed into a functional material that can be used for mine pit backfilling and ecological restoration, reducing the environmental risks brought by solid waste storage. After considering issues such as the groundwater level and the compatibility between the pyrite slag and the pit body, the modified pyrite slag is used for mine pit backfilling to improve the stability and safety of the backfilled area and prevent the occurrence of geological disasters. Soil improvement and vegetation restoration are carried out in the backfilled area to repair the ecosystem damaged by mining activities and improve the regional environmental quality.
[0006] To solve the above problems, the specific technical solution of the present invention is as follows: A method for using pyrite slag solid waste for mine pit backfilling and ecological restoration, including the following steps: 1) Conduct an environmental risk assessment on the pyrite slag solid waste. Through leaching experiments, detect relevant indicators of the pyrite slag, clarify whether the results meet the solid waste standards, and judge whether the environmental risk is acceptable; 2) Judge the relationship between the groundwater level and the bottom elevation of the backfilled mine pit: If the groundwater level is below the bottom elevation of the backfilled mine pit, there is no need to consider it, and backfilling can be carried out directly; if the groundwater level is above the bottom elevation of the backfilled mine pit, the water level needs to be first lowered to a position 0.5 m below the bottom of the mine pit, and then anti-seepage treatment and backfilling work are carried out; 3) Judge the compatibility problem between the pyrite slag and the pit body; If the amount of slag is more than the capacity of the mine pit, decentralized landfill, reduction treatment, and resource utilization are carried out; if the amount of slag is less than the capacity of the mine pit, backfilling operations are carried out on the bottom of the mine pit, and operations are carried out in accordance with the management specifications of the storage site, and backfilling can be carried out in multiple times according to the actual situation; 4) The pyrite slag that meets the requirements of steps 1) to 3) is used for mine pit backfilling. After backfilling is completed, the backfilled area is closed to prevent rainwater from entering the backfilled area, and a barrier layer and a covering soil layer are set up; 5) In the mine pit backfilled area, carry out ecological restoration work, including soil improvement and vegetation restoration.
[0007] The specific steps of step 1) are as follows: Detect the heavy metal concentration and pH value indicators of the pyrite slag through leaching experiments. If the solid waste standards are met, the pyrite slag can be crushed and screened for pretreatment and then backfilled; if not, a background investigation is carried out based on the results of the concentration detection to judge whether the environmental risk is acceptable, and corresponding measures such as solidification / stabilization treatment, modification treatment, or landfill treatment are taken.
[0008] The steps of the modification treatment are as follows: 1.1) pH adjustment: Mix the pretreated pyrite cinder with alkaline substances to adjust its pH value to neutral or weakly alkaline, so as to reduce its impact on soil acidification; 1.2) Organic matter addition: Add organic matter to the pyrite cinder to improve its adsorption capacity and water retention performance. The addition amount of organic matter is 5% - 10% of the weight of the pyrite cinder; 1.3) Cementitious material addition: Mix the pyrite cinder with cementitious materials in a certain proportion to improve its strength and stability, which is suitable for mine pit backfilling.
[0009] The anti-seepage treatment step in step 2) is as follows: Select cohesive soil for backfilling. The backfilling height is 1 m, backfilled in two layers, each layer not more than 0.5 m, and the compaction coefficient is not less than 0.90. The saturated permeability coefficient after being treated by compaction and other measures is not more than 1.0×10-7 cm / s.
[0010] In step 3), if the amount of slag is more than the capacity of the mine pit, the decentralized backfilling is as follows: Combine with surrounding abandoned mine pits, low-lying areas or subsidence areas, and disperse the treatment of the slag to ensure that the backfilling amount matches the capacity of the mine pit; The reduction treatment is as follows: Reduce the volume and increase the landfill density through mechanical compaction; The resource utilization is as follows: Part of the pyrite cinder can be used as raw materials for building materials to produce cement and bricks, realizing resource recycling and reducing the treatment cost at the same time; If the amount of slag is less than the capacity of the mine pit, carry out bottom backfilling and take temporary repair measures. After the backfilling is completed, cover with 200 mm of soil, sow grass seeds for temporary repair, and subsequent multiple backfillings can be carried out without landfill closure.
[0011] In step 4), the barrier layer uses modified compacted clay materials, and its anti-seepage performance should be at least equivalent to a permeability coefficient of 1.0×10-7 cm / s, and the thickness is not less than 0.50 m; Covering soil layer: The thickness should meet the requirements of the "TD / T 1036 Quality Control Standards for Land Reclamation", which can not only effectively prevent the pyrite cinder from being exposed on the ground surface, reduce the environmental risks brought by weathering and rain erosion, but also provide sufficient soil support for vegetation growth.
[0012] Step 5) specifically includes the following steps: 5.1) Plant selection: After landfill closure, preferably select plant varieties with strong resistance to pests and diseases, adapted to harsh environments such as barren soil, high survival rate and strong reproduction ability for vegetation restoration to ensure the long-term effectiveness and stability of the restoration effect. The selected plants are native plants adapted to the natural geographical conditions of the mining area; 5.2) Land category: The restored land category should be forest land, including arbor forest land and shrub forest land; 5.3) Seedling specifications and planting methods: Should meet the requirements of "GB 6000 Quality Grading of Nursery Stock for Main Afforestation Tree Species" and "GB / T 15776 Afforestation Technical Regulations".
[0013] The beneficial effects of the present invention are: 1. Significant environmental benefits: The present invention effectively reduces the pollution of the environment caused by solid waste storage by using pyrite slag for mine backfilling and ecological restoration, while repairing the ecosystem destroyed by mining activities and significantly improving the regional environmental quality.
[0014] 2. High resource utilization efficiency: The present invention converts pyrite slag into functional materials through modification, thereby achieving efficient resource utilization of solid waste and reducing the use of natural soil and stone resources.
[0015] 3. Reduced project costs: Using pyrite slag as backfill material reduces the comprehensive cost of mine backfill and ecological restoration, which has significant economic benefits.
[0016] 4. Long-lasting ecological restoration effect: It not only achieves short-term ecological restoration effects, but also ensures the long-term stability of the restoration area and the continuous improvement of ecological functions. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a flow chart of the repair method of the present invention. DETAILED DESCRIPTION
[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.
[0019] Take the “Pyrite slag backfilling project for a historical abandoned mine in Fushun City” as an example: a historical abandoned mine in Fushun is about 1.00km long from east to west and about 0.30km wide from north to south, covering an area of about 0.30km 2 The mine capacity is about 9 million m 3 The volume of a certain abandoned pyrite slag pile is about 3.5 million m 3 In this embodiment, the abandoned mine pit is backfilled with pyrite slag according to the following method.
[0020] like Figure 1 As shown, a method for using pyrite slag solid waste for mine backfilling and ecological restoration comprises the following steps: 1) Conduct environmental risk assessment on pyrite slag solid waste, test the heavy metal concentration, pH value and other indicators of pyrite slag through leaching experiments, clarify whether the results meet the solid waste standards, and determine whether the environmental risks are acceptable; After detection, some pyrite cinder does not meet the Class I solid waste standard. According to the results of concentration detection, environmental risk assessment is carried out, and the unsatisfied cinder is taken for modification and solidification treatment measures. The modification treatment measures are as follows: Through pH adjustment: Mix the pretreated pyrite cinder with alkaline substances (such as lime, calcium hydroxide, etc.) to adjust its pH value to neutral or weakly alkaline (pH 6.5 - 8.0) to reduce its impact on soil acidification; Organic matter addition: Add organic matter (such as humic acid, biochar, etc.) to the pyrite cinder to improve its adsorption capacity and water retention performance. The addition amount of organic matter is 5% - 10% of the weight of pyrite cinder; Cementitious material addition: Mix the pyrite cinder with cementitious materials (such as cement, fly ash, etc.) in a certain proportion to improve its strength and stability; 2) Judge the relationship between the groundwater level and the bottom elevation of the backfilled pit: The on-site groundwater level is higher than the bottom elevation of the pit. Therefore, before backfilling, take precipitation measures to lower its water level to a position 0.5 m below the bottom of the pit, and then carry out anti-seepage treatment and backfilling work; 3) Judge the compatibility problem between pyrite cinder and the pit body; 3.1) When the amount of cinder is less than the capacity of the pit, carry out bottom backfilling and temporary vegetation restoration: Manage it according to the storage site, set an anti-seepage layer, choose cohesive soil for backfilling, the backfilling height is 1 m and it is backfilled in two layers, each layer is 0.5 m, the compaction coefficient is not less than 0.90, and the saturated permeability coefficient after being compacted and treated by artificial modification and other measures is not greater than 1.0×10 -7 cm / s; 3.2) Temporary vegetation restoration: Optimally select herbaceous plants with strong stress resistance and adapted to infertile soil; The selected plant is alfalfa. Alfalfa is sown, and the soil covering is about 200 mm, making temporary restoration preparations for subsequent backfilling, providing basic conditions and meeting environmental protection requirements at the same time; 4) The subsequent pyrite cinder can continue to be used for pit backfilling. When the pit is filled or no longer undertakes new storage and landfill tasks, the closure operation should be started within 2 years, the backfilled area should be closed to prevent rainwater, etc. from entering the backfilled area, and a barrier layer and a covering soil layer should be set; 4.1) The barrier layer uses modified compacted clay-like materials to prevent the pyrite cinder from being exposed to the ground surface for a long time, and its anti-seepage performance should be at least equivalent to a permeability coefficient of 1.0×10 -5 cm / s, and the thickness is not less than 0.50 m.
[0021] 4.2) The thickness of the covering soil layer is not less than 0.5 m, providing sufficient soil support for vegetation growth and reducing environmental risks brought by weathering and rain erosion.
[0022] 4.3) After landfill closure, the land category is restored to forest land, and the selected plants are Robinia pseudoacacia and Amorpha fruticosa. Robinia pseudoacacia and Amorpha fruticosa are interplanted at a row spacing of 1:1, with a row spacing of 1.5 m × 1.5 m, and 1-year-old grade-I seedlings with a ground diameter of 1 cm are used.
[0023] 4.4) Drainage ditches are set around the backfilled pit area after landfill closure to drain the upstream water collection to the downstream and then out of the site to ensure that there is no long-term water accumulation in the site.
[0024] The present invention establishes a method for using pyrite slag for pit backfilling and ecological restoration, which can not only realize the resource utilization of solid waste, but also provide a new solution for geological environment treatment.
Claims
1. A method for using pyrite slag solid waste for mine backfilling and ecological restoration, characterized in that It includes the following steps: 1) Conduct an environmental risk assessment on pyrite slag solid waste. Detect relevant indicators of pyrite slag through leaching experiments, clarify whether the results meet the solid waste standards, and judge whether the environmental risk is acceptable; 2) Judge the relationship between the groundwater level and the bottom elevation of the backfilled pit: If the groundwater level is below the bottom elevation of the backfilled pit, there is no need to consider it, and backfilling can be carried out; If the groundwater level is above the bottom elevation of the backfilled pit, the water level needs to be first lowered to a position 0.5 m below the bottom of the pit, and then anti-seepage treatment and backfilling work are carried out; 3) Judge the compatibility problem between pyrite slag and the pit body; If the amount of slag is more than the capacity of the pit, decentralized landfill, reduction treatment and resource utilization are carried out; If the amount of slag is less than the capacity of the pit, backfilling operation is carried out on the bottom of the pit, and it is operated according to the management specifications of the storage site, and backfilling can be carried out in multiple times according to the actual situation; 4) The pyrite slag that meets the requirements of steps 1) to 3) is used for pit backfilling. After the backfilling is completed, the backfilled area is closed to prevent rainwater from entering the backfilled area, and a barrier layer and a covering soil layer are set; 5) In the pit backfilled area, ecological restoration work is carried out, including soil improvement and vegetation restoration.
2. The method for using pyrite slag solid waste for mine pit backfilling and ecological restoration according to claim 1, wherein The specific steps of step 1) are as follows: Detect the heavy metal concentration and pH value indicators of pyrite slag through leaching experiments. If the solid waste standards are met, the pyrite slag can be crushed and screened for pretreatment and then backfilled; If not, a background investigation is carried out according to the results of the concentration detection to judge whether the environmental risk is acceptable, and corresponding measures such as solidification / stabilization treatment, modification treatment or landfill treatment are taken.
3. The method for using pyrite slag solid waste for mine pit backfilling and ecological restoration according to claim 2, characterized in that, The steps of the modification treatment are as follows: 1.1) pH adjustment: Mix the pretreated pyrite slag with alkaline substances to adjust its pH value to neutral or weakly alkaline to reduce its impact on soil acidification; 1.2) Organic matter addition: Add organic matter to pyrite slag to improve its adsorption capacity and water retention performance. The addition amount of organic matter is 5% - 10% of the weight of pyrite slag; 1.3) Cementitious material addition: Mix pyrite slag with cementitious materials in a certain proportion to improve its strength and stability, which is suitable for pit backfilling.
4. The method for using pyrite slag solid waste for mine backfilling and ecological restoration according to claim 1, characterized in that, The anti-seepage treatment steps in step 2) are as follows: Select cohesive soil for backfilling. The backfilling height is 1 m and it is backfilled in two layers, with each layer not exceeding 0.5 m. The compaction coefficient is not less than 0.90, and the saturated permeability coefficient after treatment by compaction and other measures is not greater than 1.0×10 -7 cm / s.
5. The method for using pyrite slag solid waste for mine backfilling and ecological restoration according to claim 1, wherein In step 3), if the amount of slag is more than the capacity of the pit, the decentralized backfilling is as follows: Combine with surrounding abandoned pits, low-lying areas or subsidence areas to disperse the treatment of the slag to ensure that the backfilling amount matches the capacity of the pit; The reduction treatment is as follows: Reduce the volume and increase the landfill density through mechanical compaction; The resource utilization is as follows: Part of the pyrite slag can be used as raw materials for building materials to produce cement and bricks, realizing resource reuse and reducing the treatment cost at the same time; If the amount of slag is less than the capacity of the pit, bottom backfilling of the pit is carried out and temporary repair measures are taken. After the backfilling is completed, cover with 200 mm of soil and sow grass seeds for temporary repair. If the site is not closed, multiple backfillings can be carried out subsequently.
6. The method for using pyrite slag solid waste for mine backfilling and ecological restoration according to claim 1, wherein, In step 4), the barrier layer is made of modified compacted clay materials, and its anti-seepage performance should be at least equivalent to a permeability coefficient of 1.0×10 -7 cm / s and the thickness should be not less than 0.50 m; Covering soil layer: The thickness should meet the requirements of the "TD / T 1036 Quality Control Standards for Land Reclamation", which can not only effectively prevent pyrite slag from being exposed on the ground surface, reduce the environmental risks brought by weathering and rain erosion, but also provide sufficient soil support for vegetation growth.
7. The method for using pyrite slag solid waste for mine backfilling and ecological restoration according to claim 1, wherein The specific steps of step 5) are as follows: 5.1) Plant selection: After landfill closure, plant varieties with strong resistance to pests and diseases, adaptability to harsh environments such as infertile soil, high survival rates, and strong reproductive abilities are preferably selected for vegetation restoration to ensure the long-term effectiveness and stability of the restoration effect. The plants selected are native plants adapted to the natural geographical conditions of the mining area. 5.2) Land category: The restored land category should be forest land, including arbor forest land and shrub forest land. 5.3) Seedling specifications and planting methods: They should meet the requirements of "GB 6000 Quality Grading of Nursery Stocks for Main Afforestation Tree Species" and "GB / T 15776 Afforestation Technical Regulations".