Artificial soil and preparation method and application thereof

Abstract

The invention relates to artificial soil and a preparation method and application thereof, and relates to the technical field of ecological environment. The artificial soil is prepared from the following raw materials: alumina dehydrated slime, sand and organic matters, and the mass ratio of the alumina dehydrated slime to the sand to the organic matters is (93-98): (1-4): (0.1-2). The invention further provides a preparation method of the artificial soil, resource utilization of waste can be achieved, the ecological restoration cost can be reduced, remarkable economic benefits and ecological benefits can be created, and the preparation method has wide application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of ecological environment, and particularly relates to an artificial soil and its preparation method and application. Background Art

[0002] For every 1 ton of alumina produced, 1.0 - 2.5 tons of ore mud will be discharged. The disposal of bauxite tailing mud restricts the sustainable development of the alumina industry.

[0003] A large amount of stockpiled tailing mud not only occupies a large area of land, but also brings risks of dam break and ecological environment in karst areas where fissures, pipelines and sinkholes are relatively developed. Although a few comprehensive utilization technologies of tailing mud have been developed at present, including recovering valuable metal resources, preparing building and environmental protection materials, manufacturing microcrystalline glass, etc., these technologies have problems such as off-site transportation and small consumption. Technologies that can consume a large amount of ore mud are still very lacking. Summary of the Invention

[0004] In order to solve the above technical problems, the object of the present invention is to provide an artificial soil and its preparation method and application. The preparation method of the artificial soil of the present invention is simple, which can not only realize the resource utilization of waste, reduce the cost of ecological restoration, but also create significant economic and ecological benefits, and has broad application prospects.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] The first object of the present invention is to provide an artificial soil, which comprises the following raw materials: dehydrated bauxite mud, sand, organic matter. Further, the mass ratio of the dehydrated bauxite mud, the sand, and the organic matter is 93 - 98:1 - 4:0.1 - 2.

[0007] The beneficial effect of the present invention is that bauxite mud is a solid waste generated during the mining and beneficiation of bauxite, and its main components are fine-grained mineral particles and rock debris. The mud usually has a high mineral content, but its particle structure is dense, and its air permeability and water retention are poor, which has certain limitations when directly used for plant growth. By adding a small amount of sand to the mud, the coarse-grained structure of the sand can improve the air permeability and drainage of the mud and prevent soil compaction. Through reasonable proportioning and adding additives, artificial soil with excellent performance can be prepared from the mud. The present invention can not only realize the resource utilization of waste, reduce the cost of soil improvement, but also create significant economic and ecological benefits, and has broad application prospects.

[0008] On the basis of the above technical solution, the present invention can also be improved as follows.

[0009] Further, the particle size of the bauxite dewatered sludge is 5 μm to 1.2 mm; the particle size of the sand is 0.6 mm to 2 mm.

[0010] Further, the mass ratio of the bauxite dewatered sludge, the sand, and the organic matter is 95 - 96.9:3 - 4:0.1 - 1.

[0011] The beneficial effect of adopting the above further scheme is that through reasonable proportioning and adding additives, artificial soil with excellent performance can be prepared using the sludge.

[0012] The second object of the present invention is to provide a method for preparing artificial soil, including the following steps: adding sand and organic matter to the bauxite dewatered sludge for cultivation to obtain artificial soil.

[0013] Further, the humidity during the cultivation is 60% - 80%.

[0014] Further, the humidity during the cultivation is 70%.

[0015] Further, the temperature during the cultivation is 20°C - 30°C, and the time is 50d - 70d.

[0016] Further, the temperature during the cultivation is 25°C, and the time is 60d.

[0017] The third object of the present invention is to provide an application of the artificial soil, using the artificial soil for land reclamation in soil - scarce areas, plant planting, urban greening, ecological restoration, soilless cultivation, and / or landscape design.

[0018] The beneficial effect of the present invention is that preparing artificial soil from the sludge not only has a large consumption capacity but also has a cost advantage. Taking the Pingguo bauxite mine area as an example, the sludge storage tank built with an investment of more than 200 million yuan can only be used for five years, and the annual cost of treating the sludge is more than 50 million yuan. The cost of preparing artificial soil from the sludge is less than half of the traditional disposal technology. In addition, the artificial soil prepared from the sludge can be used for backfilling and reclamation of goaf areas, which can improve the ecological environment of the mining area while consuming a large amount of sludge, and is a win - win solution for in - situ large - scale ecological disposal of tailing sludge and solving the serious shortage of ecological reclamation soil sources in the mining area. The artificial soil prepared from the sludge can also be used for rocky desertification control in karst areas, cultivation of flower seedlings, and other application scenarios.

[0019] Further, the plant includes at least one of ryegrass, celosia argentea, and sweet clover. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the ryegrass grown for 30 days in Examples 1 - 4 of the present invention;

[0021] Figure 2 It is the vegetation restoration situation of the disposal area in Example 5 of the present invention. Detailed implementation mode

[0022] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention. For those without specific technical or conditions indicated in the examples, the techniques or conditions described in the literature in this field or according to the product specifications are followed. For the reagents or instruments without the manufacturer indicated, they are all conventional products that can be purchased through regular channels.

[0023] Example 1: Preparation of artificial soil I

[0024] Add sand and organic fertilizer (from a certain farm in Guilin, with a pH value of 6.5, composed of plant ash and decomposed chicken manure. The contents of nitrogen, phosphorus, potassium and organic matter in the fertilizer are 1.67%, 2.42%, 1.03% and 35% respectively) to the dehydrated bauxite sludge (from a certain alumina company in Xipingguo, mainly composed of Al2O3 (39.9%), SiO2 (23.6%), Fe2O3 (9.3%), TiO2 (6.8%), CaO (0.5%), Na2O (0.8%) and MgO (2.3%)). Cultivate at a humidity of 70% and a temperature of 25°C for 60 days. The mass ratio of dehydrated bauxite sludge, sand and organic fertilizer is 96.7:3:0.3 to obtain artificial soil.

[0025] Examples 2 - 4:

[0026] Examples 2 - 4 are the same as Example 1, and the difference is only in the mass percentage of the raw materials of the artificial soil, and the rest of the conditions are the same as those in Example 1. The composition ratios of the artificial soil in Examples 2 - 4 are shown in Table 1:

[0027] Table 1

[0028] Group Bauxite dewatered sludge Sand Organic fertilizer Example 2 98.7％ 1％ 0.3％ Example 3 97.7％ 2％ 0.3％ Example 4 95.7％ 4％ 0.3％

[0029] Comparative examples 1 - 6:

[0030] Comparative examples 1 - 6 are the same as Example 1, and the difference is only in the mass percentage of the raw materials of the artificial soil, and the rest of the conditions are the same as those in Example 1. The composition ratios of the artificial soil in Comparative examples 1 - 6 are shown in Table 2:

[0031] Table 2

[0032]

[0033]

[0034] Example 5: Application of artificial soil

[0035] A 3m×6m bare plot was selected in a soil - scarce area in the southwest for a two - year land reclamation experiment. An excavator was used to mix bauxite dewatered sludge (from a certain alumina company in Xipingguo, mainly composed of Al2O3 (39.9%), SiO2 (23.6%), Fe2O3 (9.3%), TiO2 (6.8%), CaO (0.5%), Na2O (0.8%) and MgO (2.3%)) with sand and organic fertilizer (taken from a certain farm in Guilin, with a pH value of 6.5, composed of plant ash and decomposed chicken manure. The contents of nitrogen, phosphorus, potassium and organic matter in the fertilizer were 1.67%, 2.42%, 1.03% and 35% respectively). The mixture was turned over and piled up 3 - 4 times and stacked for 30 days, where the mass ratio of bauxite dewatered sludge, sand and organic fertilizer was 96.7:3:0.3. One month later, Celosia argentea and Melilotus officinalis were planted in the test area by seeding and intercropping methods.

[0036] The land reclamation effect was evaluated annually through vegetation surveys. The quadrat method was used for vegetation surveys, and the vegetation coverage of each quadrat was observed. The vegetation restoration situation in the disposal area during the test period was as Figure 2 shown. After two years, the vegetation coverage of the quadrats increased from 26.0% to 92.0%, and the number of species in the vegetation quadrats increased from 5.00 to 10.3.

[0037] Test example: Ryegrass growth test

[0038] Perennial ryegrass seeds with plump grains, no pests and consistent size were selected, disinfected in a 10% (volume fraction) sodium hypochlorite solution for 2 hours, and then rinsed 3 times with deionized water to remove residual sodium hypochlorite for standby. For the growth test, they were randomly divided into 10 groups. 1 kg of the soils of Examples 1 - 4 and Comparative Examples 1 - 6 were accurately weighed into flowerpots for each group. 60 ryegrass seeds were evenly sown in each group, and three parallel experiments were set up for each group. All flowerpots were placed in a greenhouse at 25 - 30 °C, with a light duration of 14 hours, and the soil moisture content was maintained at about 70% of the field capacity.

[0039] The germination rate of ryegrass was measured at 15 days, and the plant height of the tallest ryegrass in each pot was measured at 25 days. The dry weight of the plants was measured after drying the washed plants to a constant weight. The growth status of ryegrass growing on the dewatered sludge substrate with different sand addition rates for 30 days was as Figure 1 shown ( Figure 1 from left to right in it, the artificial soils with sand addition amounts of 1%, 2%, 3% and 4% were used, that is, the artificial soils prepared in Example 2, Example 3, Example 1 and Example 4). The effects of different sand addition rates on the biomass of ryegrass growing on the dewatered sludge substrate for 30 days are shown in Table 3.

[0040] Table 3

[0041] Ryegrass biomass (mg / pot) Germination rate (%) Plant height (cm) Dry weight (mg) Example 1 569±22.4 93.3±3.33 12.6±0.91 589±14.8 Example 2 109±6.32 42.7±2.26 6.01±0.49 109.8±9.62 Example 3 182±15.6 69.3±4.11 7.68±0.47 169±11.0 Example 4 425±32.7 81.6±6.32 9.11±0.96 462±12.5 Comparative example 1 89.4±6.33 27.3±3.43 5.31±2.12 89.6±11.2 Comparative example 2 366±9.24 69.6±5.26 8.36±1.98 389±13.5 Comparative example 3 425±12.0 92.8±4.52 13.5±0.93 597±14.8 Comparative example 4 192±7.52 53.7±5.45 8.18±0.87 215±14.8 Comparative example 5 542±12.9 90.8±4.12 8.82±1.2 456±15.1 Comparative example 6 459±17.2 89.3±5.77 10.2±0.6 569±10.4

[0042] It can be seen from Table 3 that:

[0043] The organic fertilizer significantly increased the biomass of ryegrass, but the best effect was achieved when 3% sand was added. The reason may be that the sand increased the porosity of the sludge, which was more conducive to drainage and ventilation. In addition, in the results of germination rate, plant height, and dry weight, the data of Example 1 were significantly better than those of Comparative Examples 1-6. It can be seen that the solution of this application is the best.

[0044] In summary, the present invention can not only realize the resource utilization of waste, reduce the cost of soil improvement, but also create significant economic and ecological benefits, and has broad application prospects.

[0045] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. An artificial soil, characterized in that, The artificial soil comprises the following raw materials: dehydrated bauxite sludge, sand, and organic matter, and the mass ratio of the dehydrated bauxite sludge, the sand, and the organic matter is 93-98:1-4:0.1-2.

2. The artificial soil according to claim 1, characterized in that, The particle size of the dehydrated bauxite sludge is 5 μm-1.2 mm; the particle size of the sand is 0.6 mm-2 mm.

3. The artificial soil according to claim 2, characterized in that, The mass ratio of the dehydrated bauxite sludge, the sand, and the organic matter is 95-96.9:3-4:0.1-1.

4. A method for preparing an artificial soil according to any one of claims 1 to 3, characterized in that, The preparation method comprises the following steps: adding sand and organic matter to the dehydrated bauxite sludge for cultivation to obtain the artificial soil.

5. The preparation method of an artificial soil according to claim 4, characterized in that, The humidity during the cultivation is 60%-80%.

6. The preparation method of an artificial soil according to claim 4, wherein The humidity during the cultivation is 70%.

7. A method for preparing an artificial soil according to claim 4, characterized in that The temperature during the cultivation is 20°C-30°C, and the time is 50 d-70 d.

8. The preparation method of an artificial soil according to claim 7, wherein, The temperature during the cultivation is 25°C, and the time is 60 d.

9. Application of an artificial soil, characterized in that, The artificial soil according to any one of claims 1-3 is used for land reclamation, plant planting, urban greening, ecological restoration, soilless cultivation, and / or landscape design.

10. The application of an artificial soil according to claim 9, characterized in that, The plant includes at least one of ryegrass, celosia, and sweet clover.

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