A tailings sand soil conditioner, a method for ecological restoration of tailings sand, and applications thereof

Abstract

The present invention belongs to the technical field of mine tailings restoration, and specifically relates to a tailings soil conditioner, a mine tailings ecological restoration method and application. The tailings soil conditioner comprises raw materials in the following weight ratio: 100-120 parts of rice straw, 1-5 parts of rhizobia, and 30-35 parts of humic acid fertilizer; after applying the soil conditioner in the mine tailings area, leguminous plants are planted. The tailings soil conditioner can be used for mine tailings ecological restoration and reducing the metal content in the soil, and has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of mine tailings restoration, and particularly relates to a tailings soil conditioner, a mine tailings ecological restoration method and application thereof. Background Art

[0002] There are various reasons for soil pollution, such as metal pollution, organic matter pollution, inorganic matter pollution, etc. Among them, the tailings produced by metal mining have low nutrient content, poor water retention performance and high heavy metal content, which become one of the main reasons for soil pollution. At present, there are many tailings after copper-molybdenum, lead-zinc and other metal mining. Since tailings are not suitable for vegetation growth, the ecological environment in the mining areas is poor. How to improve the ecological environment of these tailings areas has become a research hotspot.

[0003] Hao Xiuzhen et al. (Hao Xiuzhen, Zhou Dongmei, Qian Haiyan. Effects of Amendments on the Properties of Mixed Soil of Copper Mine Tailings and Vegetable Garden Soil and the Growth of Ryegrass [J]. Rural Eco-Environment, 2003.) used montmorillonite, straw and chicken manure as amendments to study the effects of different amendments on the properties of mixed soil of copper tailings and vegetable garden soil and the growth of ryegrass. The results showed that adding montmorillonite had no significant effect on the growth of ryegrass at different growth stages. After treatment with straw and chicken manure, although it was not conducive to the growth of ryegrass (the first and second crops) at the beginning stage, but as time went on, the biomass of the third and fourth crops of blackberry grass increased significantly, showing a good aftereffect. Mei Juan et al. (Mei Juan. Research on the Restoration, Treatment and Utilization of Farmland Polluted by Lead-Zinc Mine Tailings [D]. Shanxi University.) studied the restoration methods of farmland polluted by zinc mine tailings in the Guangxi Dajiang River Basin. They studied the improvement effects of three improvement treatment methods (single application of lime-sodium hydroxide or combined application with organic fertilizer and silkworm excrement) on heavy metal polluted soil and the biomass of plants such as Pennisetum hydridum, and finally concluded that the combined application of lime-sodium hydroxide and silkworm excrement had the best improvement effect.

[0004] The above-mentioned mine tailings soil improvement methods use organic matter or natural substances as the main amendments. Although the methods are relatively environmentally friendly, the nutrient components in organic matter or natural substances are relatively limited and lack biological activity. Therefore, the improvement effect cannot fully meet the requirements. In recent years, probiotics such as lactic acid bacteria and photosynthetic bacteria have been used for composting organic matter to obtain a soil conditioner with sufficient fertility and easy-to-absorb nutrients. However, the types of available probiotics are few, which limits the development of microbial-natural substance repair agents. Therefore, the present invention studies a new microbial use that can be used to improve the quality of mine tailings, and develops a tailings soil conditioner based on microorganisms and natural substances. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a tailings soil conditioner, a mine tailings ecological restoration method and application thereof.

[0006] The first object of the present invention is to provide a tailings sand soil conditioner, comprising raw materials in the following parts by weight:

[0007] 100 - 120 parts of straw, 1 - 5 parts of rhizobia, 30 - 35 parts of humic acid fertilizer;

[0008] The above materials are mixed to obtain the tailings sand soil conditioner.

[0009] Preferably, the above tailings sand soil conditioner comprises raw materials in the following parts by weight:

[0010] 100 parts of straw, 1 part of rhizobia, 30 parts of humic acid fertilizer.

[0011] Preferably, for the above tailings sand soil conditioner, the rhizobia is Rhizobium leguminosarum H10 CGMCC No. 11878, and the leguminous plant is pea.

[0012] The second object of the present invention is to provide an application of the above tailings sand soil conditioner, and the tailings sand soil conditioner is used to reduce the heavy metal content in the soil.

[0013] Preferably, for the application of the above tailings sand soil conditioner, the tailings sand soil conditioner is used to repair the ecology of tailings sand.

[0014] The third object of the present invention is to provide a method for ecological restoration of tailings sand. After applying the soil conditioner described in claim 1 to the tailings sand area, leguminous plants are planted.

[0015] Preferably, for the above method for ecological restoration of tailings sand, the restoration method is as follows:

[0016] Step 1, prepare the tailings sand soil conditioner and leguminous plants

[0017] Prepare materials according to the mass ratio of 100 - 120 parts of straw, 1 - 5 parts of rhizobia, and 30 - 35 parts of humic acid fertilizer, and prepare leguminous plants;

[0018] Step 2, dig planting pits in the tailings sand area;

[0019] Step 3, move the prepared tailings sand soil conditioner and leguminous plants into the planting pits, and fill the pits with the soil from the tailings sand area;

[0020] Step 4, water to moisten the soil in the tailings sand area;

[0021] Repeat the above steps 1 - 4 once a year, and measure the metal content in the soil every year until the environmental standard is reached.

[0022] Preferably, in the above method for ecological restoration of mine tailings, in step 1, the method for preparing the tailings soil conditioner is as follows: Mix the above materials according to the mass ratio of 100-120 parts of straw (the straw is crushed into straw fragments of 2-3 cm), 1-5 parts of rhizobia, and 30-35 parts of humic acid fertilizer;

[0023] In step 3, the method for transferring the tailings soil conditioner and the plants into the planting pits is as follows:

[0024] Sprinkle the tailings soil conditioner into the planting pits, plant leguminous plant seedlings with a planting height of 15-20 cm in each planting pit, and fill the pits with soil from the mine tailings area.

[0025] Preferably, in the above method for ecological restoration of mine tailings, in step 1, the preparation methods for the tailings soil conditioner and the leguminous plants are as follows:

[0026] Make a three-layer structure net bag. The outermost layer contains straw fragments of 2-3 cm crushed from straw, the middle layer contains humic acid fertilizer, and the inner layer is sprinkled with pea rhizobia H10 inoculant. The roots of the leguminous plant seedlings are wrapped in the inner layer, and the seedling leaves are located outside the net bag to form a plant system to be planted;

[0027] In step 3, plant the plant systems one by one into the planting pits, and fill the pits with soil from the mine tailings area.

[0028] Preferably, the application of the above tailings soil conditioner further includes step 5:

[0029] After harvesting the leguminous plants, use EM bacteria to decompose the leguminous plant straws, return them to the field, and sprinkle grass seeds;

[0030] Half a month before planting leguminous plants in the second year, harvest the grass and return it to the field. Then, repeat the operations of steps 1-4 once after half a month;

[0031] Repeat the operation methods of the above two paragraphs, and measure the metal content in the soil every year until it meets the environmental standards, and finally plant grass seeds.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The humic acid fertilizers used in the examples and experiments of the present invention are sodium humate (specifically, the super sodium humate product of Jinan Xinfuyuan Chemical Co., Ltd., which is a good agricultural fertilizer and is often used as an aquaculture fertilizer in the prior art) or potassium humate (specifically, the ore-source fulvic acid potassium product of Shandong Xinhongyan New Materials Co., Ltd., in which the humic acid content is about 55%, the fulvic acid content is about 50%, the potassium chloride content is about 1%, and the pH is 8-10). Potassium humate can promote the rooting of flowers and fruit trees, improve the soil, increase soil fertility, and can supplement the carbon source for the mine tailings soil and is environmentally friendly.

[0034] Straw is soft in texture, can keep warm and moisturize, can make up for the defects of ore tailings not being heat-preserving and moisture-retaining, improve the living environment of vegetation, promote the growth of vegetation, and reduce the vegetation mortality rate. In addition, straw contains protein, fat and fiber, which can supplement the nitrogen source for the ore tailings soil.

[0035] Rhizobium leguminosarum H10 CGMCC No.11878 (CN106754484A, this strain is prior art, and the present invention has developed a new use for this strain) grows together with leguminous plants, utilizes nutrients with each other, enhances the vitality of leguminous plants, and moreover, the fruits of leguminous plants after maturity are rich in nutrients such as protein. After multiple crops of planting, the heavy metal content gradually decreases, and the environment of the ore tailings area is revegetated and the ecology is restored. The soil metal degradation experiment found that Rhizobium leguminosarum H10 CGMCC No.11878 can degrade copper, molybdenum and barium metals.

[0036] The present invention mixes humic acid and straw for use, supplements the two main elements of carbon source and nitrogen source required for the growth of microorganisms, and increases the fertility of the ore tailings soil.

[0037] 2. When the present invention uses the tailings soil conditioner to repair the ecology of the ore tailings area, the straw, humic acid fertilizer and rhizobia are placed in an outer, middle and inner three-layer structure, which is an improvement made by fully considering the physical and biochemical characteristics of each material. Although the crushed straw contains a lot of nutrient elements, most of them are macromolecules and are not easily absorbed. Therefore, in this embodiment, it is placed in the outermost layer to first play the role of heat preservation and moisture preservation. With the growth of plants and the action of Rhizobium leguminosarum H10 and various microorganisms in the environment, the nutrient components in the straw are gradually degraded into small molecule substances that can be absorbed by plants. Therefore, the "outer, middle and inner three-layer structure" is a design of nutrient slow release.

[0038] The present invention places Rhizobium leguminosarum H10 in the innermost layer, which is in direct contact with the transplanted pea roots, facilitating the attachment of the bacteria to the roots and forming a symbiotic system as early as possible. The humic acid fertilizer is placed in the middle layer. On the one hand, it provides nutrients, and on the other hand, it separates the plant roots from the straw. Because although the crushed straw can keep warm and moisturize, the moisture is likely to exist in the shape of liquid droplets. If it is in direct contact with the plant roots, there will be a risk of soaking the roots. Moreover, it is difficult for the roots to attach to the crushed straw and grow. The particle size of the humic acid fertilizer is small, and it also has the function of heat preservation and moisture preservation, and the moisture has good dispersibility in the humic acid fertilizer. After the roots attach to Rhizobium leguminosarum H10 and the humic acid fertilizer, the viscosity becomes larger and it is easy to attach to the crushed straw.

[0039] In the present invention, the surface area of the straw pulverized material is large, and it can keep warm and retain moisture, providing a more suitable environment for the root systems of leguminous plants, facilitating the absorption of nutrients by the root systems, and also facilitating the establishment of the symbiotic system between pea rhizobia and peas. The humic acid fertilizer increases the soil fertility in the area of the original ore tailings, which is beneficial to the survival and growth of transplanted leguminous plants. In the embodiments of the present invention, pea rhizobia H10 are used to form a symbiotic system with Longwan No. 6. The two are mutually beneficial and complementary, promoting the survival of leguminous plants in the ore tailings area, facilitating the environmental revegetation in the ore tailings area, and restoring the ecology. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Results of the treatment of molybdenum by rhizobia and leguminous plants;

[0041] Figure 2 Results of the treatment of copper by rhizobia and leguminous plants;

[0042] Figure 3 Results of the treatment of barium by rhizobia and leguminous plants;

[0043] Figure 4 Schematic diagram of the method for restoring the ecology of copper-molybdenum ore tailings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] In order to enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and the accompanying drawings.

[0045] In the description of the present invention, unless otherwise specified, the reagents used are commercially available, and the methods used are conventional techniques in the art.

[0046] Example 1

[0047] A tailings sand soil conditioner, comprising the following raw materials in parts by weight:

[0048] 100 parts of straw, 1 part of rhizobia, and 30 parts of humic acid fertilizer. After mixing the above materials, a tailings sand soil conditioner is obtained. After applying the soil conditioner in the ore tailings area and then planting leguminous plants, the ecology of the ore tailings area can be improved and the metal content can be reduced.

[0049] Example 2

[0050] A tailings sand soil conditioner, comprising the following raw materials in parts by weight:

[0051] 120 parts of straw, 5 parts of rhizobia, and 35 parts of humic acid fertilizer. After mixing the above materials, a tailings sand soil conditioner is obtained. After applying the soil conditioner in the ore tailings area and then planting leguminous plants, the ecology of the ore tailings area can be improved and the metal content can be reduced.

[0052] Example 3

[0053] A tailings sand soil conditioner, comprising raw materials in the following weight ratio:

[0054] 110 parts of rice straw, 3 parts of rhizobia, and 33 parts of humic acid fertilizer. After mixing the above materials, a tailings sand soil conditioner is obtained. After applying the soil conditioner in the tailings sand area and then planting leguminous plants, the ecology of the tailings sand area can be improved and the metal content can be reduced.

[0055] Experiment 1

[0056] 1. Experimental materials

[0057] Bacterial agent: Pea rhizobia H10 CGMCC No. 11878 bacterial agent. Referring to the method in Example 2 of Chinese Patent CN106754484A, a pea rhizobia H10 bacterial agent is prepared and stored at 4°C for later use.

[0058] Leguminous plant: Pea variety Longwan No. 6.

[0059] Test soil: Garden soil.

[0060] Added metals: Molybdenum disulfide, copper dichloride dihydrate, and barium sulfate anhydrous. The addition amount of the three metals in the garden soil is 100 mg / kg.

[0061] 2. Experimental method

[0062] Blank control: 1 kg of garden soil is placed in 1 flower pot.

[0063] Metal control soil: 1 kg of garden soil, added with molybdenum disulfide, copper dichloride dihydrate, and barium sulfate anhydrous. The addition amount of molybdenum, copper, and barium metal ions in the garden soil is set to 100 mg / kg, mixed evenly and placed in 1 flower pot.

[0064] Probiotic control group: On the basis of 1 kg of blank control garden soil, add 5 g of pea rhizobia H10 bacterial agent, mix evenly, and place in 1 flower pot.

[0065] Plant control group: 1 kg of blank control garden soil is placed in 1 flower pot, and a 15-cm-high Longwan No. 6 pea seedling is transplanted. All the roots of the seedling are buried in the soil.

[0066] Compound control group: On the basis of 1 kg of blank control garden soil, add 5 g of pea rhizobia H10 bacterial agent, mix evenly, and place in 1 flower pot. Then, a 15-cm-high Longwan No. 6 pea seedling is transplanted with roots. All the roots of the seedling are buried in the soil.

[0067] Probiotic group: On the basis of 1 kg of metal control soil, add 5 g of pea rhizobia H10 bacterial agent, mix evenly, and place in 1 flower pot.

[0068] Plant group: 1 kg of metal control soil was placed in 1 flowerpot, and a 15-cm-high Longwan No. 6 seedling was transplanted. All the roots of the seedling were buried in the soil.

[0069] Composite group: On the basis of 1 kg of metal control soil, 5 g of pea rhizobia H10 inoculant was added and mixed evenly. Then it was placed in 1 flowerpot, and a 15-cm-high Longwan No. 6 seedling with roots was transplanted. All the roots of the seedling were buried in the soil.

[0070] Each of the above groups was watered thoroughly every 7 days. On the 0th day, the 1st month, and the 2nd month after the experiment was configured, the contents of molybdenum ions, copper ions, and barium ions were measured respectively. The results are shown in Table 1 and Figures 1-3 .

[0071] Table 1 Test results of molybdenum, copper, and barium contents

[0072]

[0073] The results showed that after the treatment with pea rhizobia H10 inoculant, Longwan No. 6, and their combination, the contents of molybdenum, copper, and barium in the soil were significantly reduced.

[0074] Example 4

[0075] According to Figures 1-3 the experimental results, the combined effect of pea rhizobia H10 inoculant and Longwan No. 6 had the most significant effect on reducing the contents of molybdenum, copper, and barium in the soil. Therefore, in the ecological restoration of the copper-molybdenum tailings area (the soil in the mining area with a large amount of tailings), we adopted the method of combining these two factors.

[0076] A method for ecological restoration of copper-molybdenum tailings includes the following steps:

[0077] First, mixing of tailings soil conditioner:

[0078] Mix the above materials according to the mass ratio of 100 parts of straw, 1 part of rhizobia, and 30 parts of humic acid fertilizer.

[0079] Second, dig planting pits in the copper-molybdenum tailings area of Huitongshan Copper Mine in Guazhou County, Gansu Province. The depth of the pits is 8 cm and the width is 15 cm. The row spacing of the planting pits is 20 cm and the plant spacing is 8 cm.

[0080] Third, sprinkle the tailings soil conditioner into the planting pits, 300 g for each planting pit. Plant two 15-cm-high Longwan No. 6 seedlings in each planting pit, fill the pits with the soil in the tailings area, and the leaves of the seedlings are outside the pits.

[0081] Fourth, water to moisten the soil in the tailings area.

[0082] After 2 months of planting, the first crop of Longwan No. 6 was harvested, and the copper content in the soil decreased from the original 285.2 mg / kg to 197.7 mg / kg.

[0083] Repeat the steps 1 to 4 in the second year. Harvest the second crop of Longwan No. 6 after 2 months, and the copper content in the soil is reduced to 112.4 mg / kg.

[0084] Repeat the steps 1 to 4 in the third year. Harvest the second crop of Longwan No. 6 after 2 months, and the copper content in the soil is reduced to 72.5 mg / kg.

[0085] When the metal content of the soil in the tailings area meets the standard, the soil fertility is continuously improved, and grass seeds such as ryegrass can be planted to increase the greening area of the tailings area.

[0086] Example 5

[0087] According to Figures 1-3 the experimental results, the combined effect of the pea rhizobium H10 inoculant and Longwan No. 6 has the most significant effect on reducing the contents of molybdenum, copper and barium in the soil. Therefore, when carrying out ecological restoration in the tailings area of copper molybdenum ore (the soil in the mining area with a large amount of tailings), we adopt the method of combining these two factors.

[0088] A method for ecological restoration of copper molybdenum tailings includes the following steps:

[0089] First, the production of the plant system:

[0090] For the principle of producing the plant system, refer to Figure 4 , make a three-layer net bag. The outermost layer is filled with straw crushed into straw fragments of 2-3 cm, the middle layer is filled with humic acid fertilizer, and the inner layer is sprinkled with the pea rhizobium H10 inoculant. The root systems of two Longwan No. 6 seedlings with a height of 15 cm are wrapped in the inner layer, and the seedling leaves are outside the net bag, forming a plant system to be planted. Two seedlings are placed because the growth environment in the tailings area is relatively harsh, so two seedlings are planted in one pit to reduce the vacant area caused by dead seedlings.

[0091] Second, dig planting pits in the tailings area of Huitongshan Copper Mine in Guazhou County, Gansu Province. The pits are 8 cm deep and 15 cm wide. The row spacing of the planting pits is 20 cm, and the plant spacing is 8 cm.

[0092] Third, plant the plant systems one by one into the planting pits, and fill the pits with the soil in the tailings area.

[0093] Fourth, water to make the soil moist.

[0094] Harvest the first crop of Longwan No. 6 after 2 months of planting, and the copper content in the soil is reduced from the original 291.0 mg / kg to 164.4 mg / kg.

[0095] Repeat the steps 1 to 4 in the second year. Harvest the second crop of Longwan No. 6 after 2 months, and the copper content in the soil is reduced to 98.1 mg / kg.

[0096] In the third year, repeat the steps from the first to the fourth once. After 2 months, harvest the second crop of Longwan No. 6, and the copper content in the soil is reduced to 66.3 mg / kg.

[0097] When the metal content of the soil in the tailings area meets the standard, the soil fertility is continuously improved, and grass seeds such as ryegrass can be planted to increase the greening area of the tailings area.

[0098] Example 6

[0099] This example also adopts the method of the combined action of pea rhizobia H10 bactericide and Longwan No. 6.

[0100] A method for ecological restoration of copper-molybdenum tailings includes the following steps:

[0101] The steps from the first to the fourth are carried out with reference to Example 5.

[0102] Fifth, after harvesting the leguminous plants, use EM bacteria to decompose the plant straw (refer to the straw decomposition operation conditions of the prior art, mix EM bacteria with the crushed material of plant straw with a particle size of about 3 cm, compost for 30 days, the compost height is 2 m, and cover a layer of plastic film on the compost surface), return the decomposed material to the field, and sprinkle ryegrass seeds. Ryegrass is easy to grow and not easy to die. Moreover, the decomposed material of leguminous plants provides nutrients for the growth of ryegrass, which is beneficial to restoring the vegetation coverage rate of the tailings area.

[0103] Harvest the first crop of Longwan No. 6 after 2 months of planting, and the copper content in the soil is reduced from the original 299.7 mg / kg to 143.1 mg / kg.

[0104] In the first half of the month before planting leguminous plants in the second year, harvest the ryegrass and return it to the field. Half a month after returning it to the field, repeat the steps from the first to the fourth once. After 2 months, harvest the second crop of Longwan No. 6, and the copper content in the soil is reduced to 84.3 mg / kg.

[0105] In the first half of the month before planting leguminous plants in the third year, harvest the ryegrass and return it to the field. Half a month after returning it to the field, repeat the steps from the first to the fourth once. After 2 months, harvest the second crop of Longwan No. 6, and the copper content in the soil is reduced to 40.2 mg / kg.

[0106] It should be noted that when the present invention involves a numerical range, it should be understood that any value between the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the adopted step method is the same as that of the embodiment, in order to prevent repetition, the present invention describes the preferred embodiments. Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0107] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. An ecological restoration method for mine tailings, characterized in that, Including: Step 1: Prepare the tailings sand soil conditioner and leguminous plants as follows: Make a three-layer net bag. The outermost layer contains straw crushed into straw fragments of 2-3 cm. The middle layer contains humic acid fertilizer. The inner layer is sprinkled with pea rhizobia H10 inoculant. The root system of the leguminous plant seedlings is wrapped in the inner layer, and the seedling leaves are located outside the net bag to form a plant system to be planted. Among them, the materials are prepared according to the mass ratio of 100-120 parts of straw, 1-5 parts of rhizobia, and 30-35 parts of humic acid fertilizer. Step 2: Dig planting pits in the tailings sand area. Step 3: Plant the plant systems one by one into the planting pits and fill the pits with the soil from the tailings sand area. Step 4: Water to moisten the soil in the tailings sand area. Repeat the above steps 1-4 once a year, and measure the metal content in the soil every year until the environmental standards are met.

2. The ecological restoration method of mine tailings according to claim 1, characterized in that, It includes raw materials with the following parts by weight ratio: 100 parts of straw, 1 part of rhizobia, and 30 parts of humic acid fertilizer.

3. The ecological restoration method of mine tailings according to claim 1, characterized in that, The rhizobia are pea rhizobia H10 CGMCC No.11878, and the leguminous plant is pea.

4. The ecological restoration method for mine tailings according to claim 1, characterized in that The tailings sand soil conditioner is used to reduce the heavy metal content in the soil.

5. The ecological restoration method of mine tailings according to claim 1, wherein, The tailings sand soil conditioner is used to repair the ecology of the tailings sand.

6. The ecological restoration method of mine tailings according to claim 1, wherein, It also includes Step 5: After harvesting the leguminous plants, use EM bacteria to decompose the leguminous plant straws, return them to the field, and sprinkle grass seeds. Half a month before planting leguminous plants in the second year, harvest the grass and return it to the field. Then, continue to repeat the operations of steps 1-4 once half a month later. Repeat the operation methods of the above two paragraphs, measure the metal content in the soil every year until the environmental standards are met, and finally plant grass seeds.

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