Ecological soil prepared from ardealite and method thereof

Abstract

The invention relates to the technical field of ardealite resource utilization, in particular to ecological soil prepared from ardealite and a method of the ecological soil, the ardealite is modified by an alkaline substance, and then clayey soil is added, so that the acid corrosion performance of the ardealite is reduced, the viscosity is enhanced, and the requirement for granulation is met; coal gangue, a biological matrix, a compound microbial agent and the like are supplemented to prepare an additive, and the additive is added into the modified particles to be mixed and aged, so that the properties of the soil are enhanced, free heavy metals in the ecological soil can be solidified and stabilized, the migration rate of the heavy metals is reduced, and environmental pollution caused by direct utilization of the ecological soil is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of phosphogypsum resource utilization, and in particular to ecological soil prepared by utilizing phosphogypsum and a method thereof. Background Art

[0002] Phosphogypsum is an acidic solid waste produced by the wet phosphoric acid process. Its main component is calcium sulfate dihydrate, and it also contains arsenic, cadmium, lead, chromium, mercury, thallium, F - Therefore, storing and disposing of phosphogypsum not only consumes significant land resources but also causes secondary environmental pollution. Currently, the largest volume of phosphogypsum is being utilized and consumed in the production of building materials. However, as market demand for building materials decreases, the consumption of phosphogypsum is gradually decreasing, creating a need for new disposal methods.

[0003] Phosphogypsum contains nutrients such as calcium, phosphorus, and sulfur required for plant growth. Using it in mine management and ecological restoration can meet certain ecological needs. For example, patent application number 202110685016.0 discloses that solid waste slag is crushed and mixed with cohesive and adhesive clay to form a solid waste slag powder adhesive. The clay is an organic composite soil with colloidal characteristics; the clay is derived from sludge, silt, sediment, etc. Gypsum, phosphogypsum, fly ash, or coal gangue are also added to the solid waste slag powder adhesive to solve the technical problem that the solid waste slag powder does not have soil properties.

[0004] Another example: Patent application number 202311389019.5 discloses the use of solid waste coal gangue and phosphogypsum to transform rocky desertification into black soil, with the mixed uncured modified phosphogypsum C2 material as the cementitious solidifying material, and the mixture is mixed in a mass ratio of B1 material: C2 material of 30-70:70-30, laid on the rocky desertification land and compacted, with a thickness of 200-2000mm, to form a modified phosphogypsum shale gangue layer, named "greenable concrete" layer, which constitutes a stable layer for transforming "rocky desertification land" into "black soil"; the curing and recrystallization characteristics of the modified phosphogypsum not only meet the requirements of the stability and anti-penetration of the bottom layer of the rocky desertification land, but also ensure that the plant roots can grab the elements such as phosphorus, sulfur, calcium, magnesium, and potassium in the phosphogypsum, and can also ensure that the plant roots are fully extended to the longitudinal stone interlayer below.

[0005] However, due to the poor pH value, bulk density, water retention, air permeability, electrical conductivity, salt content and other soil property indicators of phosphogypsum, it is not suitable for use in mine management and ecological restoration to repair topsoil, that is, it cannot be directly used as ecological soil. Summary of the Invention

[0006] Based on the above technical problems, the present invention provides an ecological soil prepared using phosphogypsum and a method thereof.

[0007] The specific technical solutions are:

[0008] One of the purposes of the present invention is to provide a method for preparing ecological soil using phosphogypsum, comprising the following steps:

[0009] (1) mixing phosphogypsum and alkaline material at a mass ratio of 10:0.1-1 to obtain modified phosphogypsum; mixing the modified phosphogypsum and clay soil at a mass ratio of 10:0.5-3 to prepare granules, sieving, and obtaining modified granules with a particle size of 1-5 mm;

[0010] (2) crushing the coal gangue into particles with a particle size of less than 5 mm to obtain coal gangue particles; mixing the coal gangue particles with the biological matrix and the composite microbial agent in a mass ratio of 100:1-10:0.1-1, and aging under natural conditions for 1-7 days to obtain an additive;

[0011] (3) The modified particles are mixed with additives in a mass ratio of 10:1-10 and aged for 1-7 days under natural conditions.

[0012] Phosphogypsum is modified with alkaline substances and then mixed with clay soil to obtain modified particles. At the same time, coal gangue is crushed and mixed with biological matrix and composite microbial agent, and then aged to prepare additives. The additives are then mixed with the modified particles and aged to obtain ecological soil, which enhances the soil properties, enhances the stable solidification of free heavy metals in the ecological soil, and reduces the mobility of heavy metals.

[0013] Preferably, the biomatrix is a mixture of one or more of bio-organic fertilizer, straw, sawdust, dead branches, dead leaves, and distiller's grains in any mass ratio. More preferably, the straw is a mixture of one or two of wheat straw and corn straw in equal mass ratios.

[0014] Preferably, the composite microbial agent is a mixture of Thiobacillus ferrooxidans, Bacillus subtilis, Bacillus laterosporus, Bacillus megaterium, Paenibacillus gelatinosa, Bacillus mucilaginosus, and Aspergillus niger in equal mass ratios.

[0015] Preferably, the alkaline substance is one or more of lime, lime nitrogen slag, carbide slag, etc. mixed in equal mass ratio.

[0016] Preferably, the mass ratio of the phosphogypsum to the alkaline substance is 10:0.4.

[0017] Preferably, the mass ratio of the modified phosphogypsum to the clay soil is 10:1.

[0018] Preferably, the mass ratio of the coal gangue particles to the biological matrix and the composite microbial agent is 100:5:0.3.

[0019] Preferably, the mass ratio of the modified particles to the additive is 10:5.

[0020] The clay soil used in the invention is clay yellow mud, sludge and mud discharged from sewage treatment plants, etc.

[0021] The second purpose of the present invention is to provide ecological soil prepared by the above method.

[0022] Compared with the prior art, the technical effects created by the present invention are embodied in:

[0023] The invention uses phosphogypsum as the main raw material, supplemented by alkaline substances, coal gangue, biological matrix and composite microbial agents, so as to promote the synergistic complementarity of trace elements in phosphogypsum and trace elements in coal gangue, which can meet the nutritional needs of plant growth, enhance soil properties, and solidify and stabilize free heavy metals in ecological soil, reduce the migration rate of heavy metals, and avoid environmental pollution caused by direct use of ecological soil.

[0024] The invention has a simple process flow, is easy to operate, has a low production cost, and can increase the consumption of phosphogypsum. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The invention facilitates those skilled in the art to fully understand the technical solution of the invention. Now, in combination with the content of the technical solution and the provided drawings, the following description is made of the provided drawings.

[0026] Figure 1 This is a process flow chart created for the present invention.

[0027] Figure 2 This is a photo of the ecological soil obtained in Example 1 being used to plant strawberry plants.

[0028] Figure 3 This is the test report for the ecological soil sample obtained in Example 1 for third-party testing. DETAILED DESCRIPTION

[0029] In order to facilitate those skilled in the art to correctly understand the present invention and enable those skilled in the art to fully understand the technical content of the present invention, the technical solution of the present invention is further explained below in combination with specific implementation methods and drawings. However, this explanation does not limit the scope of protection required for the present invention. The scope of protection of the present invention by those skilled in the art cannot be limited to the following explanations. Any equivalent replacement or change made by any those skilled in the art or persons familiar with the technology in this field based on the present invention and the technical solution and inventive concept of the present invention should be covered within the scope of protection of the present invention.

[0030] like Figure 1 As shown, in certain embodiments, a method for preparing ecological soil using phosphogypsum comprises the following steps:

[0031] (1) mixing phosphogypsum with an alkaline substance in a mass ratio of 10:0.1-1, for example, 10:0.1, 10:0.3, 10:0.6, 10:0.7, 10:0.9, 10:1, etc., to obtain modified phosphogypsum; mixing the modified phosphogypsum with clay soil in a mass ratio of 10:0.5-3, for example, 10:0.5, 10:1, 10:1.3, 10:1.7, 10:2, 10:3, etc., to prepare particles, sieve, and obtain modified particles with a particle size of 1-5 mm;

[0032] (2) crushing the coal gangue into particles with a particle size of less than 5 mm to obtain coal gangue particles; mixing the coal gangue particles with the biological matrix and the composite microbial agent in a mass ratio of 100:1-10:0.1-1, for example, 100:1:0.1, 100:1:0.2, 100:1:0.3, 100:1:0.5, 100:3:0.4, 100:3:0.5, 100:3:0.1, 100:5:0.1, 100:5:0.5, 100:5:0.4, 100:10:0.1, 100:10:0.3, 100:10:0.5, 10:1:0.1, etc., and aging under natural conditions for 1-7 days, for example, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, etc., to obtain an additive;

[0033] (3) The modified particles and the additives are mixed in a mass ratio of 10:1-10, for example, 10:1, 5:1, 10:3, 4:1, 5:2, 2:1, 5:3, 1:1, etc., and aged under natural conditions for 1-7 days, for example, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, etc.

[0034] By modifying phosphogypsum with alkaline substances and then adding clay soil, the acid corrosion resistance of phosphogypsum is reduced and its viscosity is enhanced to meet the needs of granulation. Additives are then prepared with coal gangue, biological matrix, composite microbial agents, etc., and added to the modified granules for mixing and aging, which enhances the soil properties and can solidify and stabilize the free heavy metals in the ecological soil, reduce the migration rate of heavy metals, and avoid environmental pollution caused by direct use of ecological soil.

[0035] In certain embodiments, the biological matrix is one or more of biological organic fertilizer, straw, sawdust, dead branches, dead leaves, and distiller's grains mixed in any mass ratio.

[0036] In certain embodiments, the straw is a mixture of one or both of wheat straw and corn straw in an equal mass ratio.

[0037] In certain embodiments, the composite microbial agent is a mixture of Thiobacillus ferrooxidans, Bacillus subtilis, Bacillus laterosporus, Bacillus megaterium, Paenibacillus gelatinosa, Bacillus colloids, and Aspergillus niger in equal weight ratios, which can enhance the solidification and stabilization effect on heavy metals.

[0038] The alkaline substance in the invention is one or more of lime, lime nitrogen slag, carbide slag and the like mixed in equal mass ratios.

[0039] In order to better verify the technical effects of the present invention, the researchers of the present invention conducted the following experimental studies:

[0040] The phosphogypsum used in the present invention is sourced from a wet-process phosphoric acid production enterprise in Guizhou Province, and its physical and chemical properties are shown in Table 1 below:

[0041] Table 1 (Unit: %)

[0042]

[0043] The clay soil adopted in the invention is sticky yellow mud.

[0044] The coal gangue used in the present invention is solid waste discharged from a coal mining enterprise in Guizhou Province. Its main components and contents are shown in Table 2 below:

[0045] Table 2

[0046]

[0047] Example 1

[0048] The method for preparing ecological soil by using phosphogypsum comprises the following steps:

[0049] (1) mixing phosphogypsum and lime nitrogen slag at a mass ratio of 10:0.2 to obtain modified phosphogypsum; mixing the modified phosphogypsum with clay soil (sticky yellow mud) at a mass ratio of 10:2 to prepare granules, sieving, and obtaining modified granules with a particle size of 1-5 mm;

[0050] (2) Grinding the coal gangue into particles with a particle size of less than 5 mm to obtain coal gangue particles; mixing the coal gangue particles with a biological matrix (corn straw) and a composite microbial agent in a mass ratio of 100:1:0.1, and aging under natural conditions for 3 days to obtain an additive;

[0051] (3) The modified particles are mixed with the additives in a mass ratio of 10:2 and aged for 7 days under natural conditions. The composite microbial agent is a mixture of Thiobacillus ferrooxidans, Bacillus subtilis, Bacillus laterosporus, Bacillus megaterium, Paenibacillus jelly, Bacillus colloidus, and Aspergillus niger in equal mass ratios.

[0052] Example 2

[0053] On the basis of Example 1, the rest are the same as Example 1, including the following steps:

[0054] (1) Phosphogypsum and lime nitrogen slag are mixed and modified in a mass ratio of 10:0.3 to obtain modified phosphogypsum; the modified phosphogypsum is mixed with clay soil (sticky yellow mud) in a mass ratio of 10:2 to prepare particles, and the particles are sieved, and the particle size is between 1-5 mm to obtain modified particles;

[0055] (2) Grinding the coal gangue into particles with a particle size of less than 5 mm to obtain coal gangue particles; mixing the coal gangue particles with a biomatrix (corn straw) and a composite microbial agent in a mass ratio of 100:5:0.3, and aging under natural conditions for 3 days to obtain an additive;

[0056] (3) The modified particles are mixed with the additives in a mass ratio of 10:3 and aged for 7 days under natural conditions.

[0057] Example 3

[0058] On the basis of Example 1, the rest are the same as Example 1, including the following steps:

[0059] (1) Phosphogypsum and lime nitrogen slag are mixed and modified in a mass ratio of 10:0.4 to obtain modified phosphogypsum; the modified phosphogypsum is mixed with clay soil (sticky yellow mud) in a mass ratio of 10:1 to prepare particles, and the particles are sieved, and the particle size is between 1-5 mm to obtain modified particles;

[0060] (2) Grinding the coal gangue into particles with a particle size of less than 5 mm to obtain coal gangue particles; mixing the coal gangue particles with a biomatrix (corn straw) and a composite microbial agent in a mass ratio of 100:5:0.3, and aging under natural conditions for 3 days to obtain an additive;

[0061] (3) The modified particles are mixed with the additives in a mass ratio of 10:4 and aged for 7 days under natural conditions.

[0062] Example 4

[0063] On the basis of Example 1, the rest is the same as Example 1, including the following steps:

[0064] (1) Phosphogypsum and lime nitrogen slag are mixed and modified in a mass ratio of 10:0.4 to obtain modified phosphogypsum; the modified phosphogypsum is mixed with clay soil (sticky yellow mud) in a mass ratio of 10:1 to prepare particles, and the particles are sieved, and the particle size is between 1-5 mm to obtain modified particles;

[0065] (2) Grinding the coal gangue into particles with a particle size of less than 5 mm to obtain coal gangue particles; mixing the coal gangue particles with a biomatrix (corn straw) and a composite microbial agent in a mass ratio of 100:5:0.3, and aging under natural conditions for 3 days to obtain an additive;

[0066] (3) The modified particles are mixed with the additives in a mass ratio of 10:5 and aged for 7 days under natural conditions.

[0067] Example 5

[0068] On the basis of Example 3, other aspects are the same as Example 3, and the composite microbial agent is a mixture of Thiobacillus ferrooxidans, Bacillus laterosporus, Paenibacillus gelatinosa, Bacillus gelatinosa, and Aspergillus niger in equal mass ratios.

[0069] Example 6

[0070] On the basis of Example 3, other aspects are the same as Example 3, and the composite microbial agent is a mixture of Thiobacillus ferrooxidans, Bacillus laterosporus, Paenibacillus gelatinosa, and Aspergillus niger in equal mass ratios.

[0071] Example 7

[0072] On the basis of Example 3, other aspects are the same as Example 3, and the composite microbial agent is a mixture of Thiobacillus ferrooxidans, Bacillus laterosporus, and Paenibacillus gelatinosa in equal mass ratios.

[0073] Experiment 1: Soil property detection

[0074] The soil properties of the ecological soil samples obtained in Examples 1 to 7 were tested, and the test results (average of 3 times) were recorded in Table 3.

[0075] Table 3

[0076]

[0077] Table 3 shows that changes in the ecological soil preparation process parameters have little impact on soil properties such as organic matter, permeability, porosity, soil aeration, and pH. This indicates that the ecological soil obtained by the present invention meets the soil property indicators and satisfies the requirements of the "Green Planting Soil" standard (CJ / T 340-2016).

[0078] Test 2: Heavy metal curing effect detection

[0079] The ecological soil samples obtained in Examples 1 to 7 were analyzed for heavy metal indicators according to the Greening Planting Soil (CJ / T 340-2016). The results are shown in Table 4 below:

[0080] Table 4 (unit: mg / kg)

[0081]

[0082] Note: The data of Example 1 is obtained by providing samples to a third party for testing (such as Figure 3 ), Examples 2 to 7 were obtained by laboratory testing (average value of 3 times).

[0083] It can be seen from Table 4 that with the increase of lime nitrogen slag and biological matrix, and controlling the dosage of composite microbial agents within an appropriate range, it will help to improve the efficiency and effect of heavy metal solidification in ecological soil, reduce the mobility of heavy metals in ecological soil, and improve the safety of ecological soil use.

[0084] Experiment 3: Ecological soil for potted plant research

[0085] The ecological soil obtained in Example 1 was used for the potted strawberry test. The growth of the potted strawberries was as follows: Figure 2 Shown: The strawberry plants are tall, strong and growing evenly.

[0086] Other matters not covered by the present invention may be implemented by referring to the prior art or known attempts by those skilled in the art.

Claims

1. A method for preparing ecological soil using phosphogypsum, characterized in that: The following steps are involved: (1) mixing phosphogypsum and an alkaline substance in a mass ratio of 10:0.1-1 to obtain modified phosphogypsum; The modified phosphogypsum and clay soil are mixed in a mass ratio of 10:0.5-3, granulated, and sieved, wherein the particle size of the particles is between 1-5 mm to obtain modified particles; (2) crushing the coal gangue into particles with a particle size of less than 5 mm to obtain coal gangue particles; mixing the coal gangue particles with the biological matrix and the composite microbial agent in a mass ratio of 100:1-10:0.1-1, and aging under natural conditions for 1-7 days to obtain an additive; (3) The modified particles are mixed with additives in a mass ratio of 10:1-10 and aged for 1-7 days under natural conditions.

2. The method for preparing ecological soil using phosphogypsum as claimed in claim 1, characterized in that: The biological matrix is one or more of biological organic fertilizer, straw, sawdust, dead branches, dead leaves, and distiller's grains mixed in any mass ratio.

3. The method for preparing ecological soil using phosphogypsum as claimed in claim 2, characterized in that: The straw is a mixture of one or two of wheat straw and corn straw in an equal mass ratio.

4. The method for preparing ecological soil using phosphogypsum as claimed in claim 1, characterized in that: The composite microbial agent is a mixture of Thiobacillus ferrooxidans, Bacillus subtilis, Bacillus laterosporus, Bacillus megaterium, Paenibacillus gelatinosa, Bacillus colloids and Aspergillus niger in equal weight ratios.

5. The method for preparing ecological soil using phosphogypsum as claimed in claim 1, characterized in that: The alkaline substance is one or more of lime, lime nitrogen slag and carbide slag mixed in equal mass ratio.

6. The method for preparing ecological soil using phosphogypsum as claimed in claim 1, characterized in that: The mass ratio of the phosphogypsum to the alkaline substance is 10:0.

4.

7. The method for preparing ecological soil using phosphogypsum as claimed in claim 1, characterized in that: The mass ratio of the modified phosphogypsum to the clay soil is 10:

1.

8. The method for preparing ecological soil using phosphogypsum as claimed in claim 1, wherein: The mass ratio of the coal gangue particles to the biological matrix and the composite microbial agent is 100:5:0.

3.

9. The method for preparing ecological soil using phosphogypsum as claimed in claim 1, characterized in that: The mass ratio of the modified particles to the additive is 10:

5.

10. Ecological soil prepared according to the method according to any one of claims 1 to 9.

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