Artificial soil body prepared based on waste slag stone of stone processing plant and preparation method of artificial soil body

Abstract

The invention belongs to the field of solid waste resource utilization, and discloses an artificial soil body prepared based on waste slag stone of a stone processing plant and a preparation method of the artificial soil body. The artificial soil body comprises a parent material layer, a leaching layer and a surface soil layer, and the preparation method of the artificial soil body comprises the following steps: (1) material treatment: mechanically crushing waste slag stones into multi-stage particle sizes, and mixing the crushed waste slag stones with mellow soil according to a specific mass ratio; (2) function synergistic enhancement: adding a water-retaining agent, an organic compound fertilizer and a compound microbial agent into different soil layer materials; and (3) structure construction: filling a mixed material according to layered design, and completing soil activation through spraying infiltration and microbial liquid spraying. According to the invention, through the synergistic effect of the particle size grading ratio of the slag stones, the mellow soil and the functional additive, the profile structure of natural soil is simulated, and the porosity, the water binding capacity and the microbial activity are optimized, so that the problems of low resource utilization efficiency of the waste slag stones, environmental problems caused by traditional landfill and scarcity of soil resources in engineering greening are solved.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization technology, specifically relating to an artificial soil body prepared from waste slag from a stone processing plant and its preparation method. Background Technology

[0002] During railway construction, the excavated earth and rock from tunnel excavation and roadbed excavation, after being processed at quarries, generate approximately 10% (by weight) of fine-particle waste. This waste, due to its small particle size range, high compressibility, low load-bearing capacity, and extremely low shear strength, deviates significantly from the design standards for foundation filling materials, making it difficult to directly apply in engineering operations. Traditional disposal methods, such as stockpiling and landfilling, not only occupy substantial land resources but also potentially cause soil erosion and water loss due to rainwater runoff and wind erosion, posing a potential threat to the local ecosystem. Furthermore, the disposal of waste slag is not only related to environmental protection but also directly impacts the economic and social benefits of railway construction. On the one hand, large quantities of waste slag require significant storage space, increasing construction costs; on the other hand, the stockpiling and landfilling of waste slag can adversely affect the living environment and health of surrounding residents, potentially leading to social conflicts and disputes. Therefore, exploring an efficient and environmentally friendly method for utilizing waste slag has become an urgent technical challenge.

[0003] It is worth noting that while these fine-particle waste rock fragments are not suitable for traditional engineering applications, their unique physicochemical properties offer new insights for the field of ecological restoration. The clay content in the waste rock fragments endows them with excellent aeration and a pore structure similar to natural soil, providing favorable conditions for subsequent soil improvement and reconstruction. Through scientific proportioning and technological innovation, these seemingly useless waste materials can be transformed into reconstructed soils with specific functions. This not only effectively addresses the problem of scarce soil resources but also enables the resource utilization of waste, reducing its negative impact on the ecological environment. However, applying waste rock fragments to soil reconstruction still faces many technical challenges. These include matching the functional requirements of the waste rock fragments with those of the target soil, the applicability of the waste rock fragments' characteristics in reconstructed soil, and their environmental impact. Therefore, it is necessary to conduct targeted research on artificial soil construction based on the performance requirements of the soil and the characteristics of the waste rock fragments. This is not only an innovation and development of traditional soil reconstruction technology but also an important way to achieve resource recycling and promote ecological civilization. Through scientific proportioning and process optimization, waste slag can be transformed into valuable reconstructed soil, which can not only solve the problem of waste slag disposal, but also provide high-quality soil materials for agriculture, forestry, urban greening and other fields, achieving a win-win situation for economic and social benefits. Summary of the Invention

[0004] The purpose of this invention is to address the prominent problems of land encroachment caused by waste slag from the stone processing industry, environmental pollution caused by traditional landfill disposal, and difficulties in vegetation restoration due to the scarcity of natural soil resources in the field of greening engineering. This invention provides an ecologically functional artificial soil based on waste slag from stone processing plants and its preparation method. It effectively solves problems such as excessive water permeability of stony substrates, lack of organic matter, and difficulty in plant establishment, significantly improves vegetation coverage and ecosystem stability, and reduces the cost of soil transportation and solid waste disposal pressure, ultimately achieving the goal of a circular ecological economy of "treating waste with waste and turning waste into soil".

[0005] This invention provides a method for preparing artificial soil based on waste slag from a stone processing plant, comprising the following steps:

[0006] S1 mechanically crushes the waste slag and sieves it into particles of 2-5 mm, 0.25-2 mm, and <0.25 mm.

[0007] S2 mixes slag with particle sizes of 2-5 mm, 0.25-2 mm and <0.25 mm in a mass ratio of 2-4:1.5-3.5:1 to form the first layer as the parent material matrix; at the same time, a water-retaining agent is added and fully mixed with the parent material matrix to obtain a parent material layer with a height of about 20-30 cm.

[0008] S3 mixes 0.25-2 mm slag with the original soil at a mass ratio of 4-8:1 to form a second layer, which serves as the leaching layer matrix; at the same time, a water-retaining agent is added and fully mixed with the leaching layer matrix to obtain the leaching layer.

[0009] S4 involves uniformly mixing 0.25-2 mm and < 0.25 mm slag with the original soil at a mass ratio of 0.2-0.8 : 0.5-2 : 0.5-2 to construct a third layer as the topsoil matrix; commercial organic compound fertilizer is added and thoroughly mixed with the topsoil matrix to obtain the topsoil layer, i.e., the vegetation planting layer;

[0010] S5 lays the second layer on top of the first layer, and the third layer on top of the second layer. Water is then used to soak the soil, and its moisture content is controlled to be no less than 25%.

[0011] In a specific implementation,

[0012] In S1, slag with particle sizes of 2-5 mm, 0.25-2 mm and <0.25 mm are mixed evenly in a mass ratio of 3:2.5:1.

[0013] In a specific implementation,

[0014] In S2, apply the water-retaining agent at a rate of 1-3 kg / mu (e.g., 2 kg / mu) and mix it thoroughly with the parent material matrix;

[0015] The height of the parent material layer is 15-35 cm, more preferably 20-30 cm.

[0016] In a specific implementation,

[0017] In S3, 0.25-2 mm slag and original soil are mixed evenly at a mass ratio of 5-6:1;

[0018] Apply the water-retaining agent at a rate of 3-7 kg / mu (e.g., 5 kg / mu) and mix it thoroughly with the leaching layer matrix;

[0019] The thickness of the leaching layer is 5-30 cm, preferably 10-20 cm.

[0020] Preferably, the water-retaining agent is a superabsorbent resin.

[0021] In a specific implementation,

[0022] Mix the 0.25-2 mm and < 0.25 mm slag and the original soil at a mass ratio of 0.5:1:1 until they are homogeneous;

[0023] Add commercial organic compound fertilizer at a rate of 20-60 kg / mu (e.g., 40 kg / mu) and mix thoroughly with the topsoil substrate;

[0024] The topsoil layer thickness is 3-15 cm, preferably 5-10 cm.

[0025] In the preferred embodiment,

[0026] S6 controls the soil moisture content to be no less than 25%;

[0027] Optionally, it also includes

[0028] S6 applies microbial inoculants to the topsoil layer at a rate of 2.5-6.5 kg / mu (e.g., 4.5 kg / mu);

[0029] In a preferred embodiment, the microbial flora of the microbial agent includes Pseudomonas sp., Stenotrophomonas sp., Bacillus halotolerans, Bacillus siamensis, and Aspergillus japonicus; more preferably, the preservation numbers of Pseudomonas and Stenotrophomonas are CG MCC No. 12894 and CGMCC No. 12897, respectively; the preservation numbers of Stenotrophomonas and Bacillus siamensis are CGMCC No. 19502 and CGMCC No. 19505, respectively; and the preservation number of Aspergillus japonicus is CGMCC No. 7700.

[0030] The present invention also provides artificial soil obtained by the preparation method described above.

[0031] Further, the application of the aforementioned artificial soil as a soil material in agriculture, forestry, and urban greening is provided.

[0032] It also provides the application of the artificial soil as a soil material in plant cultivation, or in soil improvement or vegetation restoration.

[0033] This invention innovatively adopts a three-pronged approach: "geological soil formation process simulation - modular design of matrix functions - directional regulation of biological activity." Referencing the structural differentiation characteristics of natural soil vertical profiles and the properties of waste slag, it biomimetically constructs layered heterogeneous soil suitable for vegetation growth. By introducing water-retaining agents, organic compound slow-release fertilizers, and compound functional microbial agents, it overcomes the technical bottlenecks of traditional simple slag backfilling, such as loose soil structure, poor water and fertilizer retention capacity, and low microbial activity. This results in a near-natural soil system that combines physical stability, slow nutrient release, and biological adaptability, promoting integrated innovation in solid waste resource utilization and ecological governance technologies. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the soil layers.

[0035] Figure 2 This is a comparison diagram of the physical properties of slag and topsoil.

[0036] Figure 3 This is a comparison chart of the chemical properties of slag and topsoil. Different lowercase letters indicate that the same index shows significant differences between slag and topsoil (P < 0.05).

[0037] Figure 4 This represents the characteristics of vegetation growth height changing over time. Detailed Implementation

[0038] The technical solution of the present invention will be further illustrated by the following examples:

[0039] I. Material preparation and soil layer construction of artificial soil

[0040] The substrate includes: waste slag (from the China Railway Fourth Bureau's slag and gravel processing plant, mechanically crushed and screened according to particle sizes of 2-5 mm, 0.25-2 mm, and <0.25 mm); mature soil (limestone parent material, collected from Jianshui County, Yunnan Province); considering the water retention, fertilizer retention, and stability and enhancement of biological activity of the newly constructed artificial soil, this study also selected a water-retaining agent (highly absorbent resin, Beijing Jinqiao Chemical), organic compound fertilizer (Stanley Agricultural Group Co., Ltd.), and the soil-improving microbial agent developed by the inventor (authorization announcement number: CN 115477559 B). The microbial community of the microbial agent includes Pseudomonas sp., Stenotrophomonas sp., Bacillus halotolerans, Bacillus siamensis, and Aspergillus japonicus. The preservation numbers for *Pseudomonas* and *Oligotrophomonas* are CG MCC No. 12894 and CGMCC No. 12897, respectively; the preservation numbers for *Salmonella* and *Bacillus sicca* are CGMCC No. 19502 and CGMCC No. 19505, respectively; and the preservation number for *Aspergillus japonicus* is CGMCC No. 7700.

[0041] By mixing the above materials according to different parameters, artificial soil materials can be obtained. Simultaneously, a near-natural artificial soil structure can be constructed according to a layered design (topsoil layer, leached layer, parent material layer). Figure 1 The mixture is then filled in layers, and the soil is activated by spraying and soaking with microbial liquid.

[0042] II. Pore structure and water-holding capacity characteristics of soil formed by mixing crushed stone and topsoil with different particle sizes.

[0043] To clarify the pore structure and water-holding capacity characteristics of artificial soil constructed based on materials such as slag and gravel, the physicochemical properties of the slag and gravel and the prepared soil were first determined. For example... Figure 2 As shown, the proportion of slag particles gradually decreases with decreasing particle size (from 35% to 10%). Waste slag with a particle size of 2-10 mm accounts for a relatively high proportion (65%), while slag with a particle size smaller than 0.25 mm accounts for a relatively low proportion (10%). The proportion of 2-10 mm aggregates in the topsoil is approximately 69%, indicating that the topsoil is mainly composed of silt. The particle size distribution of the slag is similar to that of the original soil aggregates.

[0044] like Figure 3 As shown, there are significant differences in the chemical properties between slag and topsoil (P<0.05). Comparative analysis revealed that the organic carbon and total nitrogen content of topsoil was significantly higher than that of slag (P<0.05), approximately 8.3 times and 3.34 times that of slag, respectively. Slag also showed significantly higher levels of trace elements such as phosphorus, potassium, calcium, and magnesium than topsoil (P<0.05), providing a material basis for the release of nutrients from the artificial soil in later stages.

[0045] Based on the physical and chemical properties of the slag and topsoil, three mixing ratios were set for 0.25-2 mm slag, < 0.25 mm slag, and topsoil in the topsoil layer: 0.5:1:1, 1:2:1, and 2:4:1, respectively. Two mixing ratios were set for 0.25-2 mm slag and topsoil in the leaching layer: 4:1 and 8:1, respectively. One mixing ratio was set for 2-5 mm, 0.25-2 mm, and < 0.25 mm slag in the parent material layer: 3:2.5:1. Considering the stability and improvement of the water and fertilizer retention of the newly constructed artificial soil, commercial organic compound fertilizer, water-retaining agent, and microbial inoculum were added to mixing ratios 1, 3, 5, 7, 9, and 11. This ensured that the carbon, nitrogen, and phosphorus content of the topsoil reached or approached the tertiary level of soil nutrients, while simultaneously improving the water-holding capacity, nutrient release capacity, and biological activity of the topsoil. Details of the mixing ratios are shown in Table 1.

[0046] In the above treatment, waste slag, topsoil, water-retaining agent, and organic compound fertilizer were thoroughly mixed according to the different material ratio parameters in Table 1 to obtain an artificial soil mixture. The mixture was then transferred to a PVC pipe (12 cm diameter, 60 cm height), and the heights of the topsoil layer, leaching layer, and parent material layer were controlled to be 5-10 cm, 15-20 cm, and 20-30 cm, respectively. Water was sprayed onto the soil from top to bottom to ensure thorough saturation. Subsequently, microbial inoculum was sprayed onto the topsoil layer. The preparation method of the microbial inoculum is based on the authorized patent: CN115477559 B. After allowing the soil to settle naturally for 7 days, a ring cutter (100 cm³ volume) was used to... 3 The immersion method and the drying method were used to determine the soil bulk density, non-capillary porosity, capillary water holding capacity, total porosity and natural water content of the topsoil layer of artificial soil under different treatments.

[0047] Table 1. Material Proportioning of Artificial Soil

[0048]

[0049] Note: "-" in the table indicates an addition amount of 0; the ratio of topsoil to slag is by mass.

[0050] As shown in Table 2, although the bulk density of the artificial soil was relatively high, the artificial soils of configurations 1, 2, 3, and 4 were close to or exceeded the control group in terms of water retention and porosity. Furthermore, the artificial soils with added microbial inoculants, water-retaining agents, and commercial compound fertilizers had significantly higher natural moisture content than those without these materials.

[0051] Table 2. Soil physical characteristics of artificial soils with different mix proportions

[0052]

[0053] III. The Impact of Artificial Soil on the Growth of Potted Plants

[0054] PVC pipes with a diameter of 12 cm and a height of 60 cm were selected as potting containers. Following the requirements for the newly constructed soil substrate (Table 1), different soil layers were constructed. The heights of the topsoil layer, leaching layer, and parent material layer of the artificial soil were set to 10 cm, 20 cm, and 30 cm, respectively. After the three soil layers were filled, the soil was irrigated by spraying to ensure thorough saturation. Microbial inoculum was then sprayed onto the topsoil layer. After 7 days of natural settling, 50 tall fescue seeds were sown in each pot, and the topsoil was tilled to cover the seeds (0.5-1 cm thick). Each treatment was replicated in triplicate. Regular watering was conducted, and the growth of the tall fescue was observed 50 days after planting.

[0055] Table 3 shows that as the ratio of topsoil to slag and topsoil increased, the growth of tall fescue gradually deteriorated. The vegetation growth effects of the artificial soil mixtures in configurations 1, 2, 3, and 4 were close to or exceeded those of the control group, indicating that artificial soil can be used as a substrate for herbaceous vegetation growth. Considering both maximizing the utilization of slag resources and the growth effect of potted plants, this study selected configuration 3 to construct the artificial soil mixture to further investigate its impact on vegetation growth under field conditions.

[0056] Table 3. Effects of different artificial soil types on tall fescue growth

[0057]

[0058] IV. The Impact of Artificial Soil on Vegetation Growth under Field Conditions

[0059] In Jianshui County, Yunnan Province, six 1 m × 1 m bare land plots (soil type: calcareous red soil) were selected. Three plots were used as control plots, and the remaining three plots were excavated with a profile depth controlled to 0.6 m. Based on the principles of potted vegetation growth effect and maximizing the utilization of slag resources, this embodiment selected the artificial soil configuration method 3 (Table 1) for field vegetation planting experiment, and tall fescue was sown at 13-17 catties per mu.

[0060] like Figure 4 As shown, after two months of continuous observation, the tall fescue is growing well. Figure 4 This indicates that artificial soil prepared from waste slag from stone processing plants can effectively meet the growth needs of vegetation.

Claims

1. A method for preparing artificial soil based on waste slag from a stone processing plant, characterized in that, It includes the following steps: S1 mechanically crushes the waste slag and sieves it into particles of 2-5 mm, 0.25-2 mm and <0.25 mm. S2 mixes slag with particle sizes of 2-5 mm, 0.25-2 mm and <0.25 mm in a mass ratio of 2-4:1.5-3.5:1 to form the first layer as the parent material matrix; at the same time, a water-retaining agent is added and thoroughly mixed with the parent material matrix to obtain a parent material layer with a height of about 20-30 cm. S3 mixes 0.25-2 mm slag with the original soil at a mass ratio of 4-8:1 to form a second layer, which serves as the leaching layer matrix; at the same time, a water-retaining agent is added and thoroughly mixed with the leaching layer matrix to obtain the leaching layer. S4 involves uniformly mixing 0.25-2 mm and < 0.25 mm slag with the original soil at a mass ratio of 0.2-0.8 : 0.5-2 : 0.5-2 to construct a third layer as the topsoil matrix; commercial organic compound fertilizer is added and thoroughly mixed with the topsoil matrix to obtain the topsoil layer, i.e., the vegetation planting layer; S5 lays the second layer on top of the first layer, and the third layer on top of the second layer. Water is then used to soak the soil, and its moisture content is controlled to be no less than 25%.

2. The preparation method according to claim 1, characterized in that, In S1, slag with particle sizes of 2-5 mm, 0.25-2 mm, and <0.25 mm are mixed evenly in a mass ratio of 3:2.5:1; The original soil was limestone parent material.

3. The preparation method according to claim 1, characterized in that, In S2, apply the water-retaining agent at a rate of 1-3 kg / mu (e.g., 2 kg / mu) and mix it thoroughly with the parent material matrix; The height of the parent material layer is 15-35 cm, more preferably 20-30 cm.

4. The preparation method according to claim 1, characterized in that, In S3, 0.25-2 mm slag and original soil are mixed evenly at a mass ratio of 5-6:1; Apply the water-retaining agent at a rate of 3-7 kg / mu (e.g., 5 kg / mu) and mix it thoroughly with the leaching layer matrix; The thickness of the leaching layer is 5-30 cm, preferably 10-20 cm; Preferably, the water-retaining agent is a superabsorbent resin.

5. The preparation method according to claim 1, characterized in that, Mix the 0.25-2 mm and < 0.25 mm slag and the original soil at a mass ratio of 0.5:1:1 until they are homogeneous; Add commercial organic compound fertilizer at a rate of 20-60 kg / mu (e.g., 40 kg / mu) and mix thoroughly with the topsoil substrate; The topsoil layer thickness is 3-15 cm, preferably 5-10 cm.

6. The preparation method according to claim 1, characterized in that, S6 controls the soil moisture content to be no less than 25%; Optionally, it also includes S6 applies microbial inoculants to the topsoil at a rate of 2.5-6.5 kg / mu (e.g., 4.5 kg / mu).

7. The preparation method according to claim 6, characterized in that, Preferably, the microbial flora of the microbial agent includes Pseudomonas sp., Stenotrophomonas sp., Bacillus halotolerans, Bacillus siamensis, and Aspergillus japonicus; more preferably, the preservation numbers of Pseudomonas and Stenotrophomonas are CG MCC No. 12894 and CGMCC No. 12897, respectively; the preservation numbers of Stenotrophomonas and Bacillus siamensis are CGMCC No. 19502 and CGMCC No. 19505, respectively; and the preservation number of Aspergillus japonicus is CGMCC No. 7700.

8. Artificial soil obtained by the preparation method according to any one of claims 1 to 7.

9. The application of the artificial soil as described in claim 8 as a soil material in agriculture, forestry, and urban greening.

10. The use of the artificial soil as described in claim 8 as a soil material in plant cultivation, or in soil improvement or vegetation restoration.

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