Sand barrier material, its preparation method and application

Abstract

The present application relates to a kind of sand barrier materials prepared from solid waste treatment product and its preparation method and application.The sand barrier material provided by the present application includes brick and coating made on at least two front surfaces of the brick;Wherein, the raw materials in the brick and the coating are mainly the products after organic solid waste treatment, which fully utilizes the characteristics of organic solid waste rich in organic matter and nutrients and high water content, combines with inorganic solid waste, and constructs special structure of mud brick sand barrier.Under the huge demand of desertification prevention and control, the material can provide a continuous disposal and utilization outlet for solid waste in desertification area and its surrounding towns, and the material can continuously provide nutrients, improve the physicochemical properties of sand particles, promote water and fertilizer conservation, realize rapid greening in sand barrier square, and realize the synergy of solid waste recycling and desertification prevention and control.

Description

Technical Field

[0001] The present invention specifically relates to a sand barrier material prepared from solid waste treatment products, a preparation method thereof, and an application thereof. Background Art

[0002] Desertification is a major environmental issue currently receiving widespread global attention. Wind-blown sand and drought are key characteristics of desert environments. Sand barriers are a key means of sand fixation in my country. Installing sand barriers on sandy land or dune surfaces effectively controls the intensity of surface sand flow and alters surface erosion, thereby achieving windbreaks and sand fixation. Sand barriers are not only a primary measure for controlling sand drift but also a crucial precursor to revegetation, playing a positive role in the restoration process. Installing sand barriers on sandy land or dune surfaces can achieve significant sand fixation and windbreaks, achieving significant sand control results. Sand barriers can be categorized by their raw materials: biomass (straw, wheat straw, rice straw, branches, etc.), mineral materials (clay, stones, etc.), and other materials (nylon mesh, sand bags, etc.). Among them, sand barriers made primarily of biomass materials, also known as grass grids, are primarily constructed using straw laid out in a grid pattern on the sand. The straw is then inserted into the sand using a shovel or other device to form a fixed structure. This prevents wind and sand from blowing, improves sand structure, increases fertility, and promotes vegetation growth. These structures have been widely used in desertification control. However, the straw and other materials used in grass grids generally come at a cost, and with the increasing demand for sand control, material costs are rising in some areas. Sand barriers made primarily of stone, also known as stone grids, offer excellent stability, but their availability is limited, their cost is high, and they are unable to improve sand structure or provide nutrients. Plants within the grids grow slowly, and their compatibility with the environment is poor. Sand barriers made primarily of clay are called clay sand barriers. Clay can improve sand grain structure and provide nutrients, but its availability is limited and expensive. There are two common methods for laying clay sand barriers: piling the material into small ridges on the sand surface, or spreading the clay flat over the sand in a dense structure. Both methods offer limited wind erosion resistance and high construction costs. The flat clay method also impedes the infiltration of precipitation, worsening moisture conditions in the dunes and hindering plant growth. Other materials, such as nylon mesh and sand bags, also face high raw material and construction costs. Furthermore, they are not easily degradable and cannot improve sand grain structure or provide nutrients. Therefore, developing a new, efficient, multifunctional, and inexpensive sand barrier material and sand control method with a stable and sustainable source to address the shortcomings of restoration methods such as grass grids and stone grids is an effective way to reduce the cost of desertification control and improve long-term effectiveness.

[0003] There is a huge demand for the treatment and disposal of organic solid wastes such as municipal sludge, restaurant kitchen waste, and garden waste in my country's cities and towns. These solid wastes are continuously generated and contain organic matter and nutrients that can improve the structure of sand or soil, increase nutrients, and improve water retention capacity. Land utilization of their treatment products is the main way to utilize resources. my country's deserts are mainly distributed in the Three North Regions, which also have a large number of towns. The organic solid wastes generated by them are used in synergistic desert control, which can serve as a sustainable and stable disposal outlet for the organic solid waste treatment products of these towns. Therefore, sand control products processed with their treatment products as the main raw materials have great cost advantages and can further reduce the cost of desert control. However, due to the different properties of desert soil and sludge stabilization products, how to prepare and use them so that they can meet the basic needs of sand control and fixation while improving the water and fertilizer retention effect of the desert, meeting plant growth, and ensuring long-term greening is still a difficult problem that needs to be solved. Summary of the Invention

[0004] The sand barrier material provided by the present invention can not only realize the efficient utilization of urban solid waste, but also the prepared sand barrier material has better water and fertilizer retention effect and sand control effect.

[0005] The method for preparing the sand barrier material provided by the present invention is simple to operate and does not require complicated equipment and complicated operations.

[0006] The sand control method provided by the present invention has excellent and long-lasting sand control effect.

[0007] The sand barrier material provided by the present invention comprises a brick and a coating formed on at least two front sides of the brick; wherein the brick is pressed from the following raw materials: the raw materials, calculated by weight, include 20-40 parts of a stabilized organic solid waste product A, 5-10 parts of phosphogypsum, 10-15 parts of fly ash, 10-15 parts of steel slag, and 0.1-1 part of a microbial agent;

[0008] The coating is prepared from a slurry formed by mixing the following raw materials with water. The raw materials, calculated by weight, include 30-50 parts of organic solid waste stabilized treatment product B, 10-15 parts of fly ash, 5-10 parts of cement, and 0.3-0.6 parts of plant seeds A.

[0009] The organic solid waste stabilization product A and the organic solid waste stabilization product B are coarse particles and fine particles obtained after screening the organic solid waste stabilization product; wherein the organic solid waste stabilization product is a product after organic solid waste treatment, has a moisture content of 35-45%, a particle size of less than 3 cm, a humus content of 25-45%, and a pH value of 6-8; based on the dry weight of the organic solid waste stabilization product, the organic matter mass proportion is 30-50%, and the total nutrient mass proportion is greater than 1%;

[0010] The particle size of the organic solid waste stabilization product A is greater than 1 mm, the moisture content is 40-50%, and the organic matter mass proportion is 40-60% based on the dry weight of the organic solid waste stabilization product A;

[0011] The particle size of the organic solid waste stabilized product B is less than 1 mm, and more than 50% of the particle size is less than 0.3 mm, the moisture content is 25-35%, and the organic matter mass accounts for 20-30% based on the dry weight of the organic solid waste stabilized product B;

[0012] The front side refers to the side consisting of the length and height when the bricks are laid as a checkered sand barrier.

[0013] According to the sand barrier material described above, the phosphogypsum is in powder form, has a particle size of <0.1 mm, an organic matter content of <0.5%, a phosphorus content of >0.5%, and a pH of 6-8.

[0014] According to the sand barrier material described above, the fly ash particle size is 10-100 μm, of which more than 50% of the particle size is less than 30 μm.

[0015] According to the sand barrier material described above, the particle size of the steel slag is less than 200 μm.

[0016] The sand barrier material is prepared from the microbial agent, which is prepared from Bacillus subtilis and actinomycetes in a mass ratio of (1-2): (1-2).

[0017] According to the sand barrier material described above, the thickness of the coating is 0.5-2 cm.

[0018] Based on the sand barrier material described above, the specifications of the bricks are (20-50cm)×(5-15cm)×(15-30cm).

[0019] Based on the sand barrier material described above, the organic solid waste stabilization treatment product is the product of urban organic solid waste after aerobic fermentation and / or anaerobic digestion and drying treatment, and the urban organic solid waste includes sludge, kitchen waste, garden waste, and straw.

[0020] Based on the sand barrier material described above, the plant seeds A are drought-resistant plant seeds.

[0021] In the above-mentioned sand barrier material, the plant seeds A are selected from one or more of Artemisia ordosica, Artemisia scoparia, Achnatherum splendens, Bermuda grass, Lolium and Aconiti sphaerocarpa.

[0022] The present invention also provides a method for preparing a sand barrier material, wherein the sand barrier material is the above-mentioned sand barrier material, comprising the following steps:

[0023] S1, screening the organic solid waste stabilization product to obtain a coarse-grained organic solid waste stabilization product A and a fine-grained organic solid waste stabilization product B;

[0024] S2, the organic solid waste stabilization treatment product A, phosphogypsum, fly ash, steel slag and microbial agent are mixed, and then a brick blank is obtained by pressing;

[0025] S3, the mud obtained by mixing the organic solid waste stabilization treatment product B, fly ash, cement, plant seeds A and water is uniformly sprayed or applied on at least two front surfaces of the brick blank, the brick blank is re-pressed, and then naturally cured, so that the sand barrier material is obtained.

[0026] According to the preparation method, the pressure during the pressing of the brick blank is 20-40 Mpa.

[0027] According to the preparation method, the water content of the mud is 70-85%, the re-pressing pressure is 10-20 Mpa, and the curing time is greater than 5 days.

[0028] The sand control method provided by the application comprises the following steps:

[0029] The sand barrier material is used to construct a mud square grid sand barrier.

[0030] Plant seeds B are sowed in the mud square grid sand barrier to realize re-greening.

[0031] According to the sand control method, the distance between adjacent two sand barrier materials is 0-3 cm.

[0032] According to the preparation method, the sand barrier material is placed on the surface of sand particles or partially buried in the sand particles, and the burying depth is 5-15 cm.

[0033] According to the preparation method, the sowed plant seeds B are coated seeds or naked seeds.

[0034] The sand barrier material provided by the application is mainly made of municipal sludge, kitchen waste, agricultural and forestry waste, fly ash, steel slag and other products after treatment of municipal organic solid waste, fully utilizes the characteristics of rich organic matter and nutrient substances and high water content of the organic solid waste, combines with inorganic solid waste, constructs a special structure mud brick sand barrier, and provides a continuous disposal and utilization outlet for solid waste in desertification areas and surrounding towns under the huge demand of desertification control.

[0035] The preparation method of the sand barrier material provided by the application only needs simple operations such as mixing, pressing and brushing, and is low in cost and convenient to operate.

[0036] The sand control method provided by the present invention has excellent and lasting water and fertilizer conservation effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The present invention provides a method for preparing the sand barrier material. DETAILED DESCRIPTION

[0038] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0039] In view of the problems of high material cost and poor water and fertilizer retention in existing sand barriers, the present invention uses the organic solid waste stabilization treatment products obtained after the treatment of organic solid waste such as sludge, kitchen waste, and garden waste as the main raw materials, compounded with raw materials such as phosphogypsum, fly ash, steel slag, and microbial agents, and prepared into bricks with a coating. The bricks are laid on the sand surface or trenched on the sand surface to form mud grids for sand control. This method has the effects of preventing and fixing sand, retaining water and improving sand, and providing nutrients. It can effectively reduce the cost of sand fixation and has a good sand control effect.

[0040] The humus content in the present invention is measured according to the NY / T 1867-2010 "Determination of soil humus composition" standard.

[0041] The organic matter quality in the present invention is measured according to the standard GB 9834-88 "Determination of soil organic matter".

[0042] The total nutrients in this invention refer to the total content of N+P2O5+K2O. The total N (calculated as N), total P (calculated as P2O5) and total K (calculated as K2O) are measured in accordance with the NY / T 525-2021 "Organic Fertilizer" standard.

[0043] The pH value of the product of organic solid waste stabilization treatment in the present invention is determined as follows: 5.00 g of air-dried sample is placed in a 100 mL beaker, 50.0 mL of water is added (boiled for 10 minutes to remove carbon dioxide and then sealed and stored at room temperature), stirred for 15 minutes, allowed to stand for 30 minutes, and then measured with a pH meter.

[0044] The method for determining the phosphorus content in phosphogypsum of the present invention refers to JC / T 2073-2011 "Determination of phosphorus and fluorine in phosphogypsum".

[0045] The pH of phosphogypsum in the present invention is determined according to the pH determination requirements in GB / T 23456-2018 "Phosphogypsum".

[0046] The sand barrier material provided by the present invention comprises a brick and a coating formed on at least two front sides of the brick;

[0047] The bricks are pressed from the following raw materials, each of which is calculated by weight, including 20-40 parts of organic solid waste stabilized treatment product A, 5-10 parts of phosphogypsum, 10-15 parts of fly ash, 10-15 parts of steel slag, and 0.1-1 part of microbial agent;

[0048] The coating is prepared from a slurry formed by mixing the following raw materials with water. The raw materials, calculated by weight, include 30-50 parts of organic solid waste stabilized treatment product B, 10-15 parts of fly ash, 5-10 parts of cement, and 0.3-0.6 parts of plant seeds A.

[0049] The organic solid waste stabilization product A and the organic solid waste stabilization product B are coarse particles and fine particles obtained after screening the organic solid waste stabilization product; the organic solid waste stabilization product is a product after organic solid waste treatment, having a moisture content of 35-45%, a particle size of less than 3 cm, a humus content of 25-45%, and a pH value of 6-8; based on the dry weight of the organic solid waste stabilization product, the organic matter content is 30-50%, and the total nutrients content is greater than 1%;

[0050] The particle size of the organic solid waste stabilization product A is greater than 1 mm, the moisture content is 40-50%, and the organic matter mass proportion is 40-60% based on the dry weight of the organic solid waste stabilization product A;

[0051] The particle size of the organic solid waste stabilization product B is less than 1 mm, and more than 50% of the particle size is less than 0.3 mm. The moisture content is 25-35%. Based on the dry weight of the organic solid waste stabilization product B, the organic matter mass accounts for 20-30%;

[0052] The front side refers to the surface composed of length and height when the bricks are laid as a checkered sand barrier.

[0053] The raw materials used in the present invention are mainly municipal sludge, restaurant kitchen waste, agricultural and forestry waste, fly ash, steel slag and other solid wastes. The characteristics of organic solid waste rich in organic matter and nutrients and high water content are fully utilized, and combined with inorganic solid waste to construct mud brick sand barriers. Under the huge demand for desertification prevention and control, it can provide a continuous disposal and utilization outlet for solid waste in desertified areas and their surrounding towns, and can continuously provide nutrients, improve the physical and chemical properties of sand particles, promote water and fertilizer conservation, achieve rapid greening within the sand barrier grid, and realize the synergy of solid waste recycling and desertification prevention and control.

[0054] The sand barrier material mud brick is divided into two layers of inner and outer layers. The inner layer: taking the stabilized product of organic solid waste coarse material as the main raw material, and compounding phosphogypsum, fly ash, steel slag, microbial agent and the like, the components thereof are basically municipal solid waste or industrial solid waste except the microbial agent, the cost is low, and the preparation is reasonable, the fly ash, the steel slag and the particles in the stabilized product of organic solid waste can form a gel product, effectively ensuring the rigidity of the sand barrier material, prolonging the service life and strengthening the long-term wind and sand resistance; the stabilized product of organic solid waste also contains a large amount of humic acid and organic matter, and has a slow-release effect with microorganisms, which can continuously supply nutrients to sand particles to promote the rapid growth of plants and improve the sand particle structure, and further sand fixation. The outer layer: taking the stabilized product of organic solid waste fine material, fly ash and cement as the main material, has good bonding effect and stability, can form a hard shell to ensure the stability of the structure of the inner layer material, and the seeds contained in the outer layer will gradually fall off from the surface with the wind and sand erosion, which can be used to supplement the grass seeds in the square, and the outer layer is also mainly made of municipal solid waste, which is low in cost and fully utilizes the municipal solid waste.

[0055] The sand barrier material provided by the application can effectively make up for the limited service life of the grass square, slow release of nutrients and slow improvement of sand particles, and has low cost and fully utilizes municipal solid waste.

[0056] Researches show that when the phosphogypsum is in powder form, the particle size is less than 0.1 mm, the organic matter content is less than 0.5%, the phosphorus content is greater than 0.5%, the pH is 6-8, the fly ash particle size is 10-100 μm and more than 50% of the particle size is less than 30 μm, and the particle size of the steel slag is less than 200 μm, the performance of the prepared sand barrier material can be further improved.

[0057] In some specific embodiments of the application, the microbial agent is prepared by compounding Bacillus subtilis and actinomycetes at a mass ratio of (1-2):(1-2).

[0058] The steel slag is composed of various oxides formed by the oxidation of impurities such as silicon, manganese, phosphorus and sulfur in pig iron in the smelting process, and salts formed by the reaction of these oxides with solvents. The content of alkaline substances such as CaO, magnesium oxide, manganese oxide and iron aluminum oxide in the steel slag is rich, which can reach more than 40%. These alkaline substances have a certain water hardness activity, which can further improve the strength and durability of the brick.

[0059] In some embodiments of the present invention, the brick size is (20-50 cm) x (5-15 cm) x (15-30 cm), i.e., the brick length is 20-50 cm, the width is 5-15 cm, and the height is 15-30 cm. The coating thickness is typically 0.5-2 cm, and can be, for example, 0.5 cm, 1 cm, 1.5 cm, 2 cm, or any range between any two of the aforementioned values.

[0060] The organic solid waste stabilization treatment product used in the present invention can be obtained by aerobic fermentation process and / or anaerobic digestion process through various combinations of raw materials, and there is no special limitation on the method of obtaining it. In some specific embodiments of the present invention, the organic solid waste stabilization treatment product is the product of urban organic solid waste after aerobic fermentation and / or anaerobic digestion drying treatment, wherein the urban organic solid waste includes sludge, kitchen waste, garden waste, and straw. Furthermore, the organic solid waste stabilization treatment product is the product of municipal sludge with a moisture content of 60-80% mixed with auxiliary materials and then subjected to aerobic fermentation and anaerobic digestion treatment, wherein the auxiliary materials include crushed garden waste or straw, and the amount of the auxiliary materials used is 10-30% of the mass of the municipal sludge with a moisture content of 60-80% based on dry weight.

[0061] It is understandable that the plant seeds A in the outer layer of the sand barrier material are preferably drought-resistant plant seeds, such as one or more of Artemisia ordosica, Artemisia scabra, Achnatherum splendens, Bermuda grass, Ryegrass and Aconite sphagnum.

[0062] The present invention also provides a method for preparing a sand barrier material, wherein the sand barrier material is the above-mentioned sand barrier material, see Figure 1 , specifically including the following steps:

[0063] S1, screening the organic solid waste stabilization product to obtain a coarse-grained organic solid waste stabilization product A and a fine-grained organic solid waste stabilization product B;

[0064] S2, mixing the organic solid waste stabilization treatment product A, phosphogypsum, fly ash, steel slag and microbial agent, and pressing to obtain bricks;

[0065] S3, the slurry obtained by mixing the organic solid waste stabilized treatment product B, fly ash, cement, plant seeds A and water is evenly sprayed or applied on at least two front sides of the brick, and then naturally cured after re-pressing to obtain the sand barrier material.

[0066] In some embodiments of the present invention, the pressure during brick pressing is 20-40 MPa. In other embodiments of the present invention, the slurry moisture content is 70-85%, the re-pressing pressure is 10-20 MPa, and the curing time is greater than 5 days.

[0067] The present invention also provides a sand control method, comprising the following steps: using the above-mentioned sand barrier material to construct a mud grid sand barrier; and then sowing plant seeds B in the mud grid sand barrier to achieve greening.

[0068] When constructing a mud grid sand barrier, the horizontal and vertical spacing between each row is 1-2 meters, and the distance between two adjacent sand barrier materials is 0-3 cm. In other words, the sand barrier materials can be laid continuously or with certain gaps left. It can be laid manually or mechanically.

[0069] When laying, the sand barrier material can be placed on the surface of the sand or partially buried in the sand, with the burial depth usually being 5-15 cm.

[0070] When sowing, plant seeds B can be coated seeds or directly sown clean seeds.

[0071] The sand control method provided by the present invention can provide good three-dimensional support, effectively restrain the displacement of soil particles, better fix quicksand, increase the roughness of the sand surface, reduce wind speed, and prevent wind and sand erosion. It has a low loss rate, a long service life, and low maintenance costs. It can effectively compensate for the shortcomings of grass grids, which have a limited service life but slow nutrient release, slow sand improvement effect, and poor durability.

[0072] The sand barrier and sand control method prepared by the solid waste treatment product of the present invention are described in detail below with reference to specific embodiments.

[0073] The stabilized organic solid waste products A and B used in the following examples and comparative examples were prepared by the following method: municipal sludge with a moisture content of 60-80% was mixed with pulverized garden waste and straw, followed by aerobic fermentation. The resulting stabilized organic solid waste products had a moisture content of 40.6%, a particle size of <3 cm, a humus content of 38.7%, a pH of 7.3, and, on a dry weight basis, an organic matter content of 43.6% and a total nutrient content (N + P2O5 + K2O) of 5.27%. The fermented products were sieved using a 1 mm pore size sieve to obtain coarse-grained stabilized organic solid waste product A and fine-grained stabilized organic solid waste product B.

[0074] Testing of the coarse-grained organic solid waste stabilization product A showed a moisture content of 45.9%, with an organic matter content of 51.2% by dry weight. Testing of the fine-grained organic solid waste stabilization product B showed a moisture content of 29.1%, with more than 50% of the particles having a diameter less than 0.3 mm, and an organic matter content of 27.8% by dry weight.

[0075] Phosphogypsum, pH 7.47, powder, no lump, particle size <0.1 mm, organic matter content 0.43wt%, phosphorus content 0.85wt%.

[0076] Fly ash, particle size 10-100μm, wherein, more than 50% particle size <30μm.

[0077] Steel slag is a basic fine particle smelting slag obtained by further grinding and screening of smelting waste of a smelting plant, particle size <200μm, rich in CaO, magnesium oxide, manganese oxide and iron-aluminum oxide and other basic substances (total mass ratio of basic substances is 45.3%).

[0078] Microbial agent is a microbial agent mixed by Bacillus subtilis and actinomycetes at a mass ratio of 1:1; wherein the Bacillus subtilis and the actinomycetes are both conventional microbial agents, and the viable bacterial count is ≥1×10 10 cfu / g.

[0079] Cement is ordinary portland cement.

[0080] Plant seed A is a mixture of dog tooth grass and meadow grass seeds at a mass ratio of 1:1.

[0081] Example 1

[0082] The present embodiment provides a sand barrier material prepared from a solid waste treatment product and a preparation method thereof, specifically as follows:

[0083] (1) Brick preparation: 30 parts of organic solid waste stabilized treatment product A, 8 parts of phosphogypsum, 12 parts of fly ash, 12 parts of steel slag, and 0.5 parts of microbial agent are fully mixed and then put into a brick press for pressing under a pressure of 30Mpa to obtain a brick blank with a size of 30cm (length) x 10cm (width) x 20cm (height).

[0084] (2) Coating preparation: 40 parts of organic solid waste stabilized treatment product B, 12 parts of fly ash, 9 parts of cement, and 0.5 parts of plant seeds are mixed with an appropriate amount of water to prepare a slurry, which is uniformly applied to the two faces composed of the length and height of the brick blank, and then the brick blank is subjected to re-pressing under a pressure of 15Mpa using a brick press, and then placed in a well-ventilated and dry place for natural curing for 20 days to obtain a formed sand barrier material (i.e. mud brick), and the coating thickness is 1±0.3cm.

[0085] Example 2

[0086] The present embodiment provides a sand barrier material prepared from a solid waste treatment product and a preparation method thereof, specifically as follows:

[0087] (1) Brick preparation: 25 parts of organic solid waste stabilized treatment product A, 5 parts of phosphogypsum, 15 parts of fly ash, 12 parts of steel slag, and 1 part of microbial agent were fully mixed, placed in a brick press, and pressed at a pressure of 30 MPa to obtain bricks of 30 cm (length) × 10 cm (width) × 20 cm (height).

[0088] (2) Coating preparation: 50 parts of organic solid waste stabilized treatment product B, 10 parts of fly ash, 5 parts of cement, and 0.6 parts of plant seeds were mixed with an appropriate amount of water to form a slurry. The slurry was evenly applied on the two sides of the brick, which consisted of the length and height. A brick press was used to press the bricks under a pressure of 15 MPa. The bricks were then placed in a well-ventilated and dry place for natural curing for 20 days to obtain a formed sand barrier material (i.e., mud brick). The coating thickness was 1±0.3 cm.

[0089] Example 3

[0090] This embodiment provides a sand barrier material prepared from solid waste treatment products and a preparation method thereof, as follows:

[0091] (1) Brick preparation: 35 parts of organic solid waste stabilized treatment product A, 10 parts of phosphogypsum, 10 parts of fly ash, 15 parts of steel slag, and 0.1 parts of microbial agent were fully mixed, placed in a brick press, and pressed at a pressure of 30 MPa to obtain bricks of 30 cm (length) × 10 cm (width) × 20 cm (height).

[0092] (2) Coating preparation: 30 parts of organic solid waste stabilized treatment product B, 14 parts of fly ash, 8 parts of cement, and 0.3 parts of plant seeds were mixed with an appropriate amount of water to form a slurry. The slurry was evenly applied on the two sides of the brick, which consisted of the length and height. A brick press was used to press the bricks under a pressure of 15 MPa. The bricks were then placed in a well-ventilated and dry place for natural curing for 20 days to obtain a formed sand barrier material (i.e., mud brick). The coating thickness was 1±0.3 cm.

[0093] Comparative Example 1

[0094] This comparative example provides a sand barrier material prepared from a solid waste treatment product and a preparation method thereof. The difference between the comparative example and Example 1 is that no cement is added during the coating preparation, as follows:

[0095] (1) Brick preparation: 30 parts of organic solid waste stabilized treatment product A, 8 parts of phosphogypsum, 12 parts of fly ash, 12 parts of steel slag, and 0.5 parts of microbial agent were fully mixed, placed in a brick press, and pressed at a pressure of 30 MPa to obtain bricks of 30 cm (length) × 10 cm (width) × 20 cm (height).

[0096] (2) Coating preparation: 40 parts of organic solid waste stabilized treatment product B, 12 parts of fly ash, and 0.5 parts of plant seeds were mixed with an appropriate amount of water to form a slurry. The slurry was evenly applied on the two sides of the brick, which consisted of the length and height. The brick was pressed under a pressure of 15 MPa using a brick press. The brick was then placed in a well-ventilated and dry place for natural curing for 20 days to obtain a formed square barrier material (i.e., mud brick). The coating thickness was 1±0.3 cm.

[0097] Comparative Example 2

[0098] This embodiment provides a sand barrier material prepared from solid waste treatment products and a preparation method thereof. The difference between this embodiment and embodiment 1 is that the sand barrier material is prepared using a conventional method, that is, the organic solid waste stabilization treatment product is directly used to make bricks without screening, and the brick surface is not coated. The details are as follows:

[0099] After fully mixing 30 parts of organic solid waste stabilized treatment product, 8 parts of phosphogypsum, 12 parts of fly ash, 12 parts of steel slag, and 0.5 parts of microbial agent, put them into a brick press and press them under a pressure of 30 MPa to obtain bricks of 30 cm (length) × 10 cm (width) × 20 cm (height). The bricks are placed in a well-ventilated and dry place for natural curing for 20 days to obtain formed sand barrier materials (i.e., mud bricks).

[0100] Field experiment:

[0101] (1) Ten pieces of sand barrier materials from the above-mentioned embodiment and comparative example were selected, and their average masses were measured. The materials were then placed side by side on the windward side of the sand dune. After being left naturally for one year, their average masses were measured again, and the average loss rate was calculated, as shown in Table 1.

[0102] Table 1 Simulation experiment results

[0103]

[0104] As can be seen from Table 1, the loss rate of the sand barrier materials prepared in the embodiments of the present invention is all below 12%, while the loss rate of the sand barrier materials prepared in Comparative Example 1 is as high as over 20%, and the loss rate of the sand barrier materials prepared in Comparative Example 2 is over 40%, indicating that the wind erosion resistance of the sand barrier materials prepared by the present invention is significantly better than that of the comparative example, and is more conducive to long-term sand fixation.

[0105] (2) The sand barrier bricks of the above embodiment and comparative example were laid in a 1.5m×1.5m grid in the same area of ​​the desert. In spring, the same amount of sand barrier bricks (12g / m 2) of Achnatherum splendens seeds. One year later, the average plant height within the grid, the biomass (i.e., total dry weight) of all plants within the grid, the moisture content of the sand (mixed at a depth of 10 cm), and the organic matter content of the sand (mixed at a depth of 10 cm) were measured and are shown in the following table:

[0106] Table 2 Experimental results

[0107]

[0108] From the above results, it can be seen that when the sand barrier material in the embodiment of the present invention is used as a sand barrier, the plant height, total plant biomass, water content and organic matter content in the grid are significantly higher than those in the control example, indicating that the sand barrier material provided by the present invention has good water and fertilizer retention effects.

[0109] Sand control application 1:

[0110] Municipal sludge with a moisture content of 75.4% was mixed with auxiliary materials (crushed garden waste and straw, at a dry weight ratio of 15% of the municipal sludge) and fermented to produce a stabilized organic solid waste product. The product had a moisture content of 38.1%, a particle size of <3 cm, a humus content of 30.2%, a pH of 6.8, an organic matter content of 35.2% by weight, and a total nutrient content (N+P2O5+K2O) of 3.5% by weight. The fermented product was sieved using a 1mm pore size sieve to produce a coarse-grained organic solid waste stabilized product A and a fine-grained organic solid waste stabilized product B. The coarse-grained organic solid waste stabilized product A had a moisture content of 41.3% and an organic matter content of 40.9% by weight. The fine-grained organic solid waste stabilized product B was tested to have a moisture content of 32.2%, 62.7% of the particles were less than 0.3 mm in size, and the organic matter content was 24.2% on a dry weight basis. The remaining raw materials were the same as in the above example.

[0111] The sand barrier material (mud bricks) prepared from the above raw materials according to the method described in Example 1 was laid horizontally and vertically in parallel rows, with 1.5m between each row. Adjacent mud bricks were closely adjacent and partially buried in the sand to a depth of 5cm. The mud bricks were manually laid to form a mud grid sand barrier. The organic matter content of the sand in the surface layer (mixed to a depth of 10cm) within the grid was 0.68%. After laying, coated Achnatherum splendens seeds were sown in the mud grid. After three months, the green coverage rate within the grid was 61%, and after one year, the green coverage rate within the grid was 93%. At this time, the organic matter content of the surface sand (mixed to a depth of 10cm) was 1.54%.

[0112] Sand control application 2:

[0113] The municipal sludge with a water content of 70.3% is mixed with auxiliary materials (crushed garden waste and straw, the amount of which is 20% of the mass of the municipal sludge in dry weight) and then subjected to aerobic fermentation treatment to obtain a stabilized product of organic solid waste. The water content of the product is 42.2%, the particle size is less than 3 cm, the humus content is 40.3%, the pH value is 7.1, the mass fraction of organic matter is 48.5% in dry weight, and the mass fraction of total nutrients (N+P2O5+K2O) is 4.3%. The product after fermentation is sieved by a sieve with a hole diameter of 1 mm to obtain coarse-grained organic solid waste stabilized product A and fine-grained organic solid waste stabilized product B. The coarse-grained organic solid waste stabilized product A is detected, and the water content is 47.6%, and the mass fraction of organic matter is 55.3% in dry weight. The fine-grained organic solid waste stabilized product B is detected, and the water content is 27.8%, the particle size of 58.1% is less than 0.3 mm, and the mass fraction of organic matter is 29.5% in dry weight. The remaining raw materials are the same as in the above examples.

[0114] The above raw materials are prepared into sand barrier materials (mud bricks) according to the method described in Example 1, and are laid in parallel along the horizontal and vertical directions, with a spacing of 2 m between each row in the horizontal and vertical directions, and a spacing of 2 cm between two adjacent mud bricks. The bricks are directly placed on the sand surface, and the mud grid sand barrier is manually laid. The organic matter content of the sand in the surface layer (10 cm deep mixed) in the grid is 0.68%. After laying, the Anemone vitifolium seeds are sown in the mud grid, and after 3 months, the greening coverage rate in the grid is 58%, and after 1 year, the greening coverage rate in the grid is 91%, and at this time, the organic matter content of the surface sand soil (10 cm deep mixed) is 1.27%.

[0115] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A sand barrier material, characterized in that: The invention comprises a brick and a coating formed on at least two front sides of the brick; The bricks are pressed from the following raw materials, which, by weight, include 20-40 parts of organic solid waste stabilized treatment product A, 5-10 parts of phosphogypsum, 10-15 parts of fly ash, 10-15 parts of steel slag, and 0.1-1 part of microbial agent; The coating is prepared from a slurry formed by mixing the following raw materials with water. The raw materials, calculated by weight, include 30-50 parts of organic solid waste stabilized treatment product B, 10-15 parts of fly ash, 5-10 parts of cement, and 0.3-0.6 parts of plant seeds A. The organic solid waste stabilization product A and the organic solid waste stabilization product B are coarse particles and fine particles obtained after screening the organic solid waste stabilization product; wherein the organic solid waste stabilization product is a product after organic solid waste treatment, has a moisture content of 35-45%, a particle size of less than 3 cm, a humus content of 25-45%, and a pH value of 6-8; based on the dry weight of the organic solid waste stabilization product, the organic matter mass proportion is 30-50%, and the total nutrient mass proportion is greater than 1%; The particle size of the organic solid waste stabilization product A is greater than 1 mm, the moisture content is 40-50%, and the organic matter mass proportion is 40-60% based on the dry weight of the organic solid waste stabilization product A; The particle size of the organic solid waste stabilized product B is less than 1 mm, and more than 50% of the particle size is less than 0.3 mm, the moisture content is 25-35%, and the organic matter mass accounts for 20-30% based on the dry weight of the organic solid waste stabilized product B; The front side refers to the side consisting of the length and height when the bricks are laid as a checkered sand barrier.

2. The sand barrier material according to claim 1, characterized in that: The phosphogypsum is in powder form, has a particle size of <0.1 mm, an organic matter content of <0.5%, a phosphorus content of >0.5%, and a pH of 6-8; and / or The fly ash particle size is 10-100 μm, of which more than 50% has a particle size of less than 30 μm; and / or The particle size of the steel slag is less than 200 μm.

3. The sand barrier material according to claim 1 or 2, characterized in that: The microbial agent is prepared by mixing Bacillus subtilis and actinomycetes in a mass ratio of (1-2): (1-2).

4. The sand barrier material according to claim 1 or 2, characterized in that: The thickness of the coating is 0.5-2 cm.

5. The sand barrier material according to claim 1 or 2, characterized in that: The specifications of the bricks are (20-50 cm)×(5-15 cm)×(15-30 cm).

6. The sand barrier material according to claim 1, characterized in that: The organic solid waste stabilization treatment product is a product of urban organic solid waste after aerobic fermentation and / or anaerobic digestion and drying treatment, and the urban organic solid waste includes sludge, restaurant kitchen waste, garden waste, and straw.

7. The sand barrier material according to claim 1 or 2, characterized in that: The plant seeds A are drought-tolerant plant seeds; and / or The plant seeds A are selected from one or more of Artemisia ordosica, Artemisia scabra, Achnatherum splendens, Bermuda grass, Lolium perenne and Stapelia serrata.

8. A method for preparing a sand barrier material, characterized in that: The sand barrier material is the sand barrier material according to any one of claims 1 to 7, comprising the following steps: S1, screening the organic solid waste stabilization product to obtain a coarse-grained organic solid waste stabilization product A and a fine-grained organic solid waste stabilization product B; S2, mixing the organic solid waste stabilization treatment product A, phosphogypsum, fly ash, steel slag and microbial agent, and pressing to obtain bricks; S3, the slurry obtained by mixing the organic solid waste stabilized treatment product B, fly ash, cement, plant seeds A and water is evenly sprayed or applied on at least two front sides of the brick, and then naturally cured after re-pressing to obtain the sand barrier material.

9. The method for preparing the sand barrier material according to claim 8, characterized in that: The pressure during brick pressing is 20-40Mpa; and / or The slurry has a moisture content of 70-85%, a re-compression pressure of 10-20 MPa, and a curing time of more than 5 days.

10. A method for sand control, characterized in that: The following steps are involved: A mud grid sand barrier is constructed using the sand barrier material according to any one of claims 1 to 7 or the sand barrier material prepared by the preparation method according to claim 8 or 9; Plant seeds B are sown in the mud grid sand barrier to achieve regreening.

11. The sand control method according to claim 10, characterized in that: When constructing mud grid sand barriers, the horizontal and vertical intervals between each row are 1-2m, and the distance between two adjacent sand barrier materials is 0-3cm; and / or the sand barrier materials are placed on the surface of the sand or partially buried in the sand, with a burial depth of 5-15cm.

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