Method for restoring soil in waste metal mine area by indocalamus

Abstract

The invention relates to the technical field of soil improvement and soil pollution treatment, and particularly discloses a method for repairing waste metal mine area soil through indocalamus. The soil is improved by adopting a composite soil passivator comprising a phosphate fertilizer, a calcium-containing substance, a clay mineral and a compost, so that the content of heavy metals in a waste metal mine area reaches the efficient growth and development range of the indocalamus, and meanwhile, a scientific planting method of the indocalamus is combined; furthermore, the soil environment of the waste metal mine area can be well repaired.

Description

Technical Field

[0001] The invention relates to the technical field of soil improvement and soil pollution control, and in particular to a method for repairing soil in abandoned metal mining areas by using indocalamus japonica. Background Art

[0002] With the continuous increase in mining activities, the problem of ecological environmental damage is becoming increasingly serious, among which soil pollution and degradation are particularly prominent. Soil improvement technology plays a vital role in mine ecological restoration. Mining activities often cause serious damage to the ecological environment, especially the damage to the soil environment, which directly affects the stability and sustainability of the ecosystem. Therefore, the application of soil improvement technology is crucial to the success of mine ecological restoration.

[0003] Existing mine soil improvement technologies include physical improvement technology, chemical improvement technology and biological improvement technology. Physical improvement technology mainly improves soil quality by changing the physical properties of the soil. Chemical improvement technology mainly changes the chemical properties of the soil by adjusting the acidity and alkalinity of the soil or applying fertilizers. Biological improvement technology mainly improves soil quality by increasing the biological activity in the soil. However, heavy metal pollution in metal mine soil is mainly multi-element complex pollution of heavy metal elements Pb, Zn, Cd, Cu, Cr and metalloid As. A single improvement technology cannot effectively improve the soil environment in metal mining areas. In addition, when plants are stressed by heavy metals, their respiration not only provides energy for normal life activities, but also provides additional energy to adapt to heavy metal stress. At this time, the plant changes from normal metabolism to metabolism in a defensive state, and normal growth is inhibited.

[0004] However, bamboo plants have good tolerance and enrichment capacity for heavy metals, and have the characteristics of large biomass, simple cultivation and high economic benefits. They have high application potential and development value in the restoration of heavy metal contaminated soil. Therefore, it is necessary to study the method of bamboo plants for soil restoration in abandoned metal mining areas. Summary of the invention

[0005] The purpose of the present invention is to overcome the problem of poor soil environment in metal mining areas in the prior art and to provide a method for repairing soil in abandoned metal mining areas using indigo bamboo. The method can better enrich heavy metals and repair the soil environment in the metal mining areas.

[0006] In order to achieve the above-mentioned object, the present invention provides a method for repairing soil in abandoned metal mining areas by using indigo bamboo, which method comprises improving the soil in the abandoned metal mining area and planting indigo bamboo;

[0007] (1) Soil improvement in abandoned metal mining areas includes:

[0008] The composite soil passivator is laid on the soil surface of the abandoned metal mining area with a laying thickness of 25-35cm. After the laying is completed, the soil is turned over with a turning depth of 40-50cm to complete the soil improvement treatment;

[0009] The composite soil passivator comprises phosphate fertilizer, calcium-containing substances, clay minerals and compost; the dosage of the composite soil passivator is 100-500 kg / mu, and the mass ratio of the phosphate fertilizer, calcium-containing substances, clay minerals and compost is 1:0.1-10:1-20:5-50;

[0010] (2) The cultivation of Indocalamus includes:

[0011] 10-30 days after the soil improvement of the abandoned metal mining area is completed, the pit planting method is used to plant indocalamus in the soil of the abandoned metal mining area, and the planting density is 120-300 pieces / mu.

[0012] By adopting the above technical scheme, the soil is improved by using a composite soil passivator including phosphate fertilizer, calcium-containing substances, clay minerals and compost, so that the heavy metal content in the abandoned metal mining area reaches the range of efficient growth and development of bamboo. At the same time, combined with the scientific planting method of bamboo, the soil environment of the abandoned metal mining area can be further better restored. DETAILED DESCRIPTION

[0013] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0014] On one hand, the present invention provides a method for repairing soil in abandoned metal mining areas by using indigo bamboo, the method comprising improving the soil in the abandoned metal mining areas and planting indigo bamboo;

[0015] (1) Soil improvement in abandoned metal mining areas includes:

[0016] The composite soil passivator is laid on the soil surface of the abandoned metal mine area with a laying thickness of 25-35cm. After the laying is completed, the soil is turned over with a turning depth of 40-50cm to complete the soil improvement treatment;

[0017] The composite soil passivator comprises phosphate fertilizer, calcium-containing substances, clay minerals and compost; the dosage of the composite soil passivator is 100-500 kg / mu, and the mass ratio of the phosphate fertilizer, calcium-containing substances, clay minerals and compost is 1:0.1-10:1-20:5-50;

[0018] (2) The cultivation of Indocalamus includes:

[0019] 10-30 days after the soil improvement of the abandoned metal mining area is completed, the pit planting method is used to plant indocalamus in the soil of the abandoned metal mining area, and the planting density is 120-300 pieces / mu.

[0020] In the present invention, in order to improve the improvement effect of the composite soil passivator on the soil environment, preferably, the dosage of the composite soil passivator is 200-400 kg / mu.

[0021] In the present invention, in order to make the phosphate fertilizer, calcium-containing substance, clay mineral and compost in the composite soil passivator have a better coordination effect and further improve the improvement effect of the composite soil passivator, preferably, the mass ratio of the phosphate fertilizer, calcium-containing substance, clay mineral and compost is 1:0.2-8:2-15:8-40.

[0022] In the present invention, reasonable control of the planting density of Indocalamus truncatum can further improve the survival rate of Indocalamus truncatum, thereby achieving the effect of improving the soil environment of abandoned metal mining areas. Preferably, the planting density of Indocalamus truncatum is 150-250 pieces / mu.

[0023] In the present invention, preferably, the phosphate fertilizer is selected from at least one of superphosphate, hydroxyapatite and calcium hydrogen phosphate.

[0024] In the present invention, preferably, the calcium-containing substance is selected from at least one of quicklime, slaked lime, limestone and calcium chloride.

[0025] In the present invention, preferably, the clay mineral is selected from at least one of sepiolite, bentonite and bentonite.

[0026] In the present invention, preferably, the compost is obtained by composting organic waste; the organic waste is selected from animal excrement, residential garbage and plant waste.

[0027] Composting refers to a biochemical process that utilizes microorganisms widely found in nature to controllably promote the conversion of degradable organic matter in solid waste into stable humus. According to the present invention, preferably, the composting includes aerobic composting of organic waste, including the following steps:

[0028] (1) mixing animal feces, household garbage and plant waste as compost materials and crushing them to a particle size of 30-60 mm, adding nitrogen to the materials so that the C / N ratio is 26-30:1, and then adding zeolite and standing for 5-8 hours; wherein the mass ratio of the animal feces, household garbage and plant waste is 1:6-10:1-10; the moisture content of the compost material after standing is preferably 50wt%-60wt%, for example, it can be 50wt%, 52wt%, 54wt%, 56wt%, 58wt%, 60wt% and the like and any range between these values;

[0029] (2) placing the material obtained in step (1) into a fermentation chamber of an aerobic composting device for fermentation for 5-10 days, wherein the temperature in the aerobic composting device is preferably 60-70° C.

[0030] In the present invention, the composting treatment method can be used to obtain compost with suitable performance, which promotes the improvement of abandoned metal mining areas by composite soil passivation agents. Preferably, the performance indicators of the compost include: pH value of 6-8, EC value of 3-5mS / cm, bulk density of 1.5-3.5g / cm 3 , particle size is 25-45mm.

[0031] In the present invention, preferably, the performance indicators of the compost include: pH value of 6.5-7.5, EC value of 3.5-4.5mS / cm, bulk density of 2-3g / cm 3 , particle size is 35-40mm.

[0032] In the present invention, preferably, the pit planting method for planting indocalamus includes: digging planting holes in the improved soil of abandoned metal mines, backfilling the topsoil, and then planting indocalamus seedlings.

[0033] In the present invention, digging a planting hole can include digging a hole around the predetermined planting point before planting the indigo bamboo. The size of the planting hole should be determined according to the size of the indigo bamboo, and it is required to accommodate all the roots of the indigo bamboo and spread them out. Avoid planting too deep or too shallow, which will hinder the growth of the indigo bamboo.

[0034] By adopting the technical scheme of the present invention, by regulating the type and amount of each passivator in the composite soil passivator and adopting a suitable indocalamus planting method, the survival rate of indocalamus is not less than 85% after soil restoration for half a year and one year, and the soil pH of the abandoned metal mine area after restoration for one year is 6.23-6.52, the concentrations of heavy metals Cd, Pb, Zn and metalloid As are greatly reduced, and the soil environment is greatly improved.

[0035] The present invention will be described in detail below through examples.

[0036] The abandoned metal mining area was divided into a number of square plots with an area of ​​1 mu (side length of about 25.8 m), and soil remediation work was carried out in different plots according to the method described in the embodiment.

[0037] Preparation Example 1

[0038] This preparation example is used to illustrate the method for preparing composts a1 and a2.

[0039] The preparation of compost a1 includes: mixing animal feces, residential garbage and plant waste according to a weight ratio of 1:6:5, crushing the mixture to a particle size of 40 mm, adding nitrogen to the mixture so that the C / N ratio is 26:1, adding zeolite and standing for 5 hours, wherein the water content of the compost after standing is 54wt%; placing the standing material in a fermentation chamber of an aerobic composting device at 60°C and fermenting for 10 days to obtain compost a1; after identification, the pH value of the compost a1 is 6.62, the EC value is 3.5mS / cm, and the bulk density is 2.1g / cm 3 , particle size is 38mm;

[0040] The preparation of compost a2 includes: mixing animal feces, residential garbage and plant waste according to a weight ratio of 1:10:4, crushing the mixture to a particle size of 50 mm, adding nitrogen to the mixture so that the C / N ratio is 28:1, adding zeolite and standing for 4 hours, wherein the water content of the compost after standing is 56wt%; placing the standing material in a fermentation bin of an aerobic composting device at 65°C and fermenting for 8 days to obtain compost a2; after identification, the pH value of the compost a2 is 6.51, the EC value is 3.8mS / cm, and the bulk density is 2.3g / cm 3 , particle size is 40mm.

[0041] Preparation Example 2

[0042] This preparation example is used to illustrate the composite soil passivators A1-A5 and B1-B3.

[0043] The composite soil passivator A1 comprises superphosphate, quicklime, sepiolite and compost a1, and the mass ratio of superphosphate, quicklime, sepiolite and compost a1 is 1:0.2:2:8;

[0044] The composite soil passivator A2 comprises calcium phosphate, quicklime, sepiolite and compost a2, and the mass ratio of calcium phosphate, quicklime, sepiolite and compost a2 is 1:5:10:20;

[0045] The composite soil passivator A3 comprises calcium phosphate, quicklime, sepiolite and compost a1, and the mass ratio of calcium phosphate, quicklime, sepiolite and compost a1 in the composite soil passivator is 1:0.1:1:5;

[0046] The composite soil passivator A4 comprises calcium phosphate, quicklime, sepiolite and compost a1, and the mass ratio of calcium phosphate, quicklime, sepiolite and compost a1 is 1:10:20:50;

[0047] The composite soil passivator A5 comprises hydroxyapatite, slaked lime, bentonite and compost a1, and the mass ratio of the apatite, slaked lime, bentonite and compost a1 is 1:0.2:2:8;

[0048] The composite soil passivator B1 includes superphosphate, quicklime and sepiolite, and the mass ratio of superphosphate, quicklime and sepiolite is 1:0.2:2;

[0049] The composite soil passivator B2 includes superphosphate, quicklime and compost a1, and the mass ratio of superphosphate, quicklime and compost a1 is 1:0.2:8;

[0050] The composite soil passivator B3 includes superphosphate, quicklime, sepiolite and compost a1, and the mass ratio of the amounts of superphosphate, quicklime, sepiolite and compost a1 is 1:15:0.5:1.

[0051] Example 1

[0052] This embodiment is used to illustrate the method of using Indocalamus japonica to repair soil in abandoned metal mining areas.

[0053] (1) Soil improvement in abandoned metal mining areas includes:

[0054] The composite soil passivator A1 was spread on the soil surface of the abandoned metal mine area at a dosage of 200 kg / mu, with a thickness of 25 cm. After the spreading, the soil was turned over to a depth of 40 cm to complete the soil improvement treatment;

[0055] (2) The cultivation of Indocalamus includes:

[0056] Fifteen days after the soil improvement of the abandoned metal mining area was completed, the pit planting method was used to plant Indocalamus fasciata in the soil of the abandoned metal mining area, with a planting density of 150 pieces per mu.

[0057] Example 2

[0058] This embodiment is used to illustrate the method of using Indocalamus japonica to repair soil in abandoned metal mining areas.

[0059] (1) Soil improvement in abandoned metal mining areas includes:

[0060] The composite soil passivator A2 with a dosage of 400kg / mu was spread on the soil surface of the abandoned metal mine area with a thickness of 30cm. After the spreading was completed, the soil was turned over with a depth of 45cm to complete the soil improvement treatment;

[0061] (2) The planting of indigo bamboo includes: 15 days after the soil improvement of the abandoned metal mining area is completed, indigo bamboo is planted in the soil of the abandoned metal mining area using the hole planting method, and the planting density is 150 pieces / mu.

[0062] Example 3

[0063] A method similar to that of Example 1 was used, except that composite soil passivator A3 was used instead of composite soil passivator A1.

[0064] Example 4

[0065] A similar method to Example 1 was used, except that an equal weight portion of composite soil passivator A4 was used to replace composite soil passivator A1.

[0066] Example 5

[0067] A similar method to Example 1 was used, except that an equal weight portion of composite soil passivator A5 was used to replace composite soil passivator A1.

[0068] Example 6

[0069] A method similar to that of Example 1 was used, except that the amount of composite soil passivator A1 was 100 kg / mu.

[0070] Example 7

[0071] A method similar to that of Example 1 was adopted, except that the dosage of composite soil passivator A1 was 500 kg / mu.

[0072] Comparative Example 1

[0073] A method similar to that of the embodiment is adopted, except that an equal weight portion of composite soil passivator B1 is used to replace composite soil passivator A1.

[0074] Comparative Example 2

[0075] A method similar to that of the embodiment is adopted, except that the composite soil passivator B2 is used in equal parts by weight to replace the composite soil passivator A1.

[0076] Comparative Example 3

[0077] A method similar to that of the embodiment is adopted, except that the composite soil passivator B3 is used in equal parts by weight to replace the composite soil passivator A1.

[0078] Test Example 1

[0079] The number of surviving bamboos was recorded half a year and one year after the soil remediation methods described in the embodiment and the comparative example were applied, and the survival rate of the bamboos was calculated, as shown in Table 1.

[0080] Test method: Plant survival rate = (number of surviving plants / total number of planted plants) x 100%.

[0081] Table 1

[0082] Example No. Survival rate after half a year / % Survival rate after one year / % Example 1 92.1 91.3 Example 2 90.3 89.4 Example 3 88.6 86.3 Example 4 86.2 85.4 Example 5 91.7 90.1 Example 6 87.2 86.1 Example 7 86.0 85.4 Comparative Example 1 56.2 51.0 Comparative Example 2 58.3 54.1 Comparative Example 3 63.2 59.4

[0083] Test Example 2

[0084] The effects of the soil remediation methods described in the above embodiments and comparative examples were verified, and the physical and chemical properties of the soil in the scrap metal mine area before and after the application of the method were detected, as shown in Table 2.

[0085] Test method:

[0086] 1. Soil pH determination: Take 1.0g soil sample, add 5ml deionized water (soil-water ratio is 1:5), mix well, put into a constant temperature oscillator, oscillate at 220r / min at room temperature for 1 hour, take out and let it stand for 30min, and then measure: redox potential meter.

[0087] 2. Total amount of Zn, Cd and Pb: According to GB / T17141.1997, three-acid digestion (HNO 3 -HClO 4 -HF), determination: flame atomic absorption spectrophotometry.

[0088] 3. Soil As analysis: According to GB / T17141.1997, digestion was performed with aqua regia and determination was performed using a dual-channel atomic fluorescence spectrophotometer.

[0089] Table 2

[0090]

[0091] It can be seen from the results in Table 1 and Table 2 that, compared with Comparative Examples 1-3, the abandoned metal mining areas repaired by the soil remediation methods required in Examples 1-7 of the present invention have a higher survival rate of planted indocalamus, and the repaired abandoned coal mining areas have suitable pH and Eh, and the contents of heavy metals Cd, Pb, Zn and metalloid As in the soil are greatly reduced. In particular, the soil environment obtained by the repair method required in Examples 1 and 2 is more excellent.

[0092] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for remediating soil in abandoned metal mining areas using Indocalamus sibiricum, characterized in that: The method includes soil improvement and planting of Indocalamus japonica in abandoned metal mining areas; (1) Soil improvement in abandoned metal mining areas includes: The composite soil passivator is laid on the soil surface of the abandoned metal mining area with a laying thickness of 25-35cm. After the laying is completed, the soil is turned over with a turning depth of 40-50cm to complete the soil improvement treatment; The composite soil passivator comprises phosphate fertilizer, calcium-containing substances, clay minerals and compost; the dosage of the composite soil passivator is 100-500 kg / mu, and the mass ratio of the phosphate fertilizer, calcium-containing substances, clay minerals and compost is 1:0.1-10:1-20:5-50; (2) The planting of indigo bamboo includes: 10-30 days after the soil improvement of the abandoned metal mining area is completed, indigo bamboo is planted in the soil of the abandoned metal mining area by using the hole planting method, and the planting density is 120-300 pieces / mu.

2. The method according to claim 1, wherein: The dosage of the composite soil passivator is 200-400kg / mu; Preferably, the mass ratio of the phosphate fertilizer, calcium-containing substance, clay mineral and compost is 1:0.2-8:2-15:8-40.

3. The method according to claim 1 or 2, wherein: The planting density of Indocalamus is 150-250 pieces per mu.

4. The method according to any one of claims 1 to 3, wherein: The phosphate fertilizer is selected from at least one of superphosphate, hydroxyapatite and calcium hydrogen phosphate.

5. The method according to any one of claims 1 to 4, wherein: The calcium-containing substance is selected from at least one of quicklime, slaked lime, limestone and calcium chloride.

6. The method according to any one of claims 1 to 5, wherein: The clay mineral is selected from at least one of sepiolite, bentonite and bentonite.

7. The method according to any one of claims 1 to 6, wherein: The compost is obtained by composting organic waste; the organic waste is selected from animal excrement, residential garbage and plant waste.

8. The method according to any one of claims 1 to 7, wherein: The performance indicators of the compost include: pH value of 6-8, EC value of 3-5mS / cm, bulk density of 1.5-3.5g / cm 3 , particle size is 25-45mm.

9. The method according to any one of claims 1 to 8, wherein: The performance indicators of the compost include: pH value of 6.5-7.5, EC value of 3.5-4.5mS / cm, bulk density of 2-3g / cm 3 , particle size is 35-40mm.

10. The method according to any one of claims 1 to 9, wherein: The hole planting method for planting bamboo includes: digging planting holes in the improved soil of abandoned metal mines, backfilling the topsoil, and then planting bamboo seedlings.

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