Sand barrier material as well as preparation method and application thereof

Abstract

The invention relates to a sand barrier material prepared from solid waste treatment products and a preparation method and application thereof. The sand barrier material provided by the invention comprises a green brick and coatings manufactured on at least two front surfaces of the green brick, the raw materials in the green brick and the coating are mainly products obtained after organic solid waste treatment, the characteristics that organic solid waste is rich in organic matter and nutrient substances and high in water content are fully utilized, the organic solid waste is combined with inorganic solid waste, the mud brick sand barrier of a special structure is constructed, and under the huge desertification prevention and control requirement, the effect is achieved. The material can provide a continuous disposal and utilization way for solid wastes in desertification regions and cities and towns around the desertification regions, and can continuously provide nutrient substances, improve the physical and chemical properties of sand grains, promote water and fertilizer retention, and realize rapid greening in sand barrier grids and coordination of solid waste recycling and desertification control.

Description

Technical Field

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

[0002] Desertification is one of the major environmental issues that has attracted widespread global attention. Wind and sand activities and drought are important characteristics of desert environments. Setting up sand barriers for engineering sand fixation is an important means of desertification control in my country. By setting up sand barriers on the surface of sandy land or sand dunes, the intensity of surface wind and sand flow can be effectively controlled and the surface erosion and accumulation conditions can be changed, thereby achieving the purpose of wind and sand fixation. Sand barriers are not only the main measure to control sand flow, but also an important leading measure to restore vegetation. They play an active role in the process of vegetation restoration. By setting up sand barriers on the surface of sandy land or sand dunes, the purpose of wind and sand fixation can be achieved, and the effect of sand control is significant. According to the different raw materials of sand barriers, they can be divided into: biomass materials (straw, wheat straw, rice straw, branches, etc.), mineral materials (clay, stones, etc.) and other materials (nylon nets, sand bags, etc.). Among them, the sand barrier made of biomass materials is also called grass grid. The grass grid mainly uses straw and other materials to lay out in a grid shape on the sand, and then inserts the straw into the sand with a shovel or device to form a fixed structure. It can prevent wind and fix sand, improve sand structure, increase fertility, and promote vegetation growth. It has been widely used in desertification control. However, the straw and other materials used in the grass grid generally require a certain cost, and with the increase in the demand for sand control, the material cost in some areas has a certain upward trend. The sand barrier made of stone as the main material is also called stone grid. Stone has good stability, but the material conditions are restricted and the cost is high. It cannot improve the sand structure and provide nutrients. The plants in the grid grow slowly and have poor compatibility with the environment. Sand barriers made of clay as the main material are called clay sand barriers. Clay can improve the structure of sand grains and provide certain nutrients, but the conditions for obtaining clay materials are also very limited and the cost is high. There are generally two ways to lay clay sand barriers: piling clay materials on the sand surface into small ridges, and spreading clay on the sand surface with a compact structure. Both methods have insufficient wind erosion resistance and high construction costs. The clay paving method will also affect the infiltration of precipitation, worsening the moisture conditions of the sand dunes, which is not conducive to plant growth. Other materials such as nylon nets and sand bags also face the problem of high raw material and construction costs, and the materials are not easy to degrade, cannot improve the structure of sand grains and provide nutrients. Therefore, developing a new type of sand barrier material and sand control method with a stable and continuous source, high efficiency, multifunctionality, and low cost to make up for 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 control effects.

[0003] There is a huge demand for the treatment and disposal of organic solid wastes such as municipal sludge, kitchen waste, and garden waste in my country's cities and towns, because these solid wastes are continuously produced and contain organic matter and nutrients, which can improve the structure of sand or soil, increase nutrients, and improve water retention capacity. The land use of their treatment products is the main way of resource utilization. my country's deserts are mainly distributed in the three northern regions, where there are also a large number of towns. The organic solid wastes produced by them are used in synergistic desert control, which can serve as a sustainable and stable disposal outlet for the treatment products of organic solid waste in these cities and 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, while being able to achieve the basic needs of sand control and fixation, can also improve the desert's water and fertilizer retention effects, meet plant growth, and ensure 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 lasting sand control effect.

[0007] The sand barrier material provided by the present invention comprises a brick blank and a coating made on at least two front sides of the brick blank; wherein the brick blank is pressed from the following raw materials, which, by weight, comprise 20-40 parts of an 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 parts of a microbial agent;

[0008] The coating is prepared from a slurry formed by mixing the following raw materials with water, wherein the raw materials, by weight, include 30-50 parts of organic solid waste stabilized 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, and has a moisture content of 35-45%, a particle size of <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 accounts for 30-50%, and the total nutrient mass accounts for >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 accounts for 40-60% based on the dry weight of the organic solid waste stabilization product A;

[0011] 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%, and the organic matter mass accounts for 20-30% based on the dry weight of the organic solid waste stabilization 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, with 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 <30 μm.

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

[0016] Based on the sand barrier material described above, the microbial agent 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] From 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] According to the sand barrier material described above, the plant seeds A are drought-resistant plant seeds.

[0021] According to the sand barrier material described above, the plant seeds A are selected from one or more of Artemisia ordosica, Artemisia sphaerocephala, Achnatherum splendens, Cynodon dactylon, Lolium perenne and Staphlomis sphaerocephala.

[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 treatment product to obtain a coarse-grained organic solid waste stabilization treatment product A and a fine-grained organic solid waste stabilization treatment product B;

[0024] S2, mixing the organic solid waste stabilization treatment product A, phosphogypsum, fly ash, steel slag and microbial agent, and pressing to obtain a brick;

[0025] S3, the slurry obtained by mixing the organic solid waste stabilization 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.

[0026] According to the preparation method described above, the pressure during the pressing of the bricks is 20-40Mpa.

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

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

[0029] Using the sand barrier material described above or the sand barrier material prepared by the above preparation method to construct a mud grid sand barrier;

[0030] Plant seeds B are sown in the mud grid sand barrier to achieve regreening.

[0031] According to the sand control method described above, 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;

[0032] According to the preparation method described above, the sand barrier material is placed on the surface of sand grains or partially buried in the sand grains, with a burial depth of 5-15 cm.

[0033] According to the preparation method described above, the plant seeds B sown are coated seeds or clean seeds.

[0034] The sand barrier material provided by the present invention mainly uses as raw materials the products of treatment of urban organic solid wastes such as municipal sludge, restaurant kitchen waste, agricultural and forestry wastes, fly ash, and steel slag. The material makes full use of the characteristics of organic solid wastes that are rich in organic matter and nutrients and have a high water content, and combines them with inorganic solid wastes to construct mud brick sand barriers with special structures. Under the huge demand for desertification prevention and control, it can not only provide a continuous disposal and utilization outlet for solid wastes in desertified areas and their surrounding cities, but also the material can continuously provide nutrients, improve the physical and chemical properties of sand particles, promote water and fertilizer retention, achieve rapid regreening within the sand barrier grid, and realize efficient coordination of solid waste recycling and desertification prevention and control.

[0035] The method for preparing the sand barrier material provided by the present invention can be realized by simple operations such as mixing, pressing, and brushing, and is low-cost and easy 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 invention discloses a method for preparing the sand barrier material. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination 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 creative work are 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 them into coated bricks, which are laid into mud grids by paving on the sand surface or digging trenches on the sand surface for sand control. This method has the effects of preventing and fixing sand, retaining water and improving sand, and providing nutrients, 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 standard NY / T 1867-2010 "Determination of soil humus composition".

[0041] The organic matter quality in the present invention is measured according to GB 9834-88 "Soil organic matter determination method".

[0042] The total nutrients in the present invention refer to N+P 2 O 5 +K 2 O content, total N (in N), total P (in P 2 O 5 Total K (in K 2 O) Measured in accordance with NY / T 525-2021 Organic Fertilizer.

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

[0044] The method for determining the phosphorus content in phosphogypsum of the present invention refers to JC / T 2073-2011 "Method for determining 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 product A, 5-10 parts of phosphogypsum, 10-15 parts of fly ash, 10-15 parts of steel slag, and 0.1-1 parts of microbial agent;

[0048] The coating is prepared from a slurry formed by mixing the following raw materials with water, wherein the raw materials, 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] Among them, the organic solid waste stabilization treatment product A and the organic solid waste stabilization treatment product B are coarse particles and fine particles obtained after screening the organic solid waste stabilization treatment product; wherein, the organic solid waste stabilization treatment product is the product after organic solid waste treatment, and its moisture content is 35-45%, the particle size is <3cm, the humus content is 25-45%, and the pH value is 6-8; based on the dry weight of the organic solid waste stabilization treatment product, the organic matter mass accounts for 30-50%, and the total nutrient mass accounts for >1%;

[0050] The particle size of the organic solid waste stabilization product A is >1 mm, the moisture content is 40-50%, and the organic matter mass accounts for 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%, and the organic matter mass accounts for 20-30% based on the dry weight of the organic solid waste stabilization product B;

[0052] The front side refers to the surface composed of length and height when the bricks are laid as a square 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 being rich in organic matter and nutrients and having a 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 retention, achieve rapid greening within the sand barrier grid, and realize the synergy of solid waste recycling and desertification prevention and control.

[0054] The mud brick of the sand barrier material is divided into two layers, inner and outer. The inner layer: the main raw material is the stabilized product of organic solid waste, combined with phosphogypsum, fly ash, steel slag, microbial agents, etc. Its components, except for the microbial agents, are basically urban solid waste or industrial solid waste, with low cost and reasonable formulation. The particles and water in the fly ash, steel slag and the stabilized product of organic solid waste can form a gel product, which effectively ensures the rigidity of the sand barrier material, prolongs its life, and strengthens its long-term resistance to wind and sand; the stabilized product of organic solid waste also contains a large amount of humic acid and organic matter, which has a slow-release effect when combined with microorganisms, can continuously supplement nutrients for sand grains to promote rapid plant growth, improve sand grain structure, and further fix sand. Outer layer: The main materials are fine materials, fly ash and cement, which are stabilized products of organic solid waste. They have good bonding and stability, and can form a hard outer shell to ensure the stability of the inner material structure. The seeds contained in the outer layer will gradually fall off from the surface as the wind and sand erode, and can be used to supplement the grass seeds in the grid. The outer layer also uses urban solid waste as the main raw material, which is low in cost and makes full use of urban solid waste.

[0055] The sand barrier material provided by the present invention can effectively make up for the shortcomings of limited service life of grass grids, slow release of nutrients, and slow sand improvement effect, and has low cost and makes full use of urban solid waste.

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

[0057] In some specific embodiments of the present invention, the microbial agent is prepared from Bacillus subtilis and actinomycetes in a mass ratio of (1-2): (1-2).

[0058] Steel slag is composed of various oxides formed by oxidation of impurities such as silicon, manganese, phosphorus, and sulfur in pig iron during the smelting process, as well as 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 oxides in steel slag is rich, reaching more than 40%. These alkaline substances have certain hydraulic activity, which can further improve the strength and durability of bricks.

[0059] In some specific embodiments of the present invention, the specifications of the brick are (20-50 cm) × (5-15 cm) × (15-30 cm), that is, the length of the brick is 20-50 cm, the width is 5-15 cm, and the height is 15-30 cm. The thickness of the coating is usually 0.5-2 cm, for example, 0.5 cm, 1 cm, 1.5 cm, 2 cm, and the range between any two of the above 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 of raw materials in various combinations, and the method of obtaining it is not particularly limited. 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 and drying treatment, wherein the urban organic solid waste includes sludge, kitchen waste, garden waste, and straw. Further, the organic solid waste stabilization treatment product is the product of municipal sludge with a moisture content of 60-80% and auxiliary materials after 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% by 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 sphaerocephala, Achnatherum splendens, Cynodon dactylon, Ryegrass and Stapelia sphaerocephala.

[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 treatment product to obtain a coarse-grained organic solid waste stabilization treatment product A and a fine-grained organic solid waste stabilization treatment 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 a brick;

[0065] S3, the slurry obtained by mixing the organic solid waste stabilization 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 specific embodiments of the present invention, the pressure during the pressing of the brick is 20-40 MPa. In some other specific embodiments of the present invention, 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.

[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 regreening.

[0068] When constructing mud grid sand barriers, the horizontal and vertical spacing between each row is 1-2m, and the distance between two adjacent sand barrier materials is 0-3cm, that is, 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, and the burial depth is usually 5-15cm.

[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, block the erosion of wind and sand, have low loss rate, long service life and low maintenance cost. It can effectively make up for the shortcomings of the grass grid with limited service life, slow release of nutrients, 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 crushed garden waste and straw, and then subjected to aerobic fermentation to obtain a stabilized organic solid waste product. The moisture content was 40.6%, the particle size was less than 3 cm, the humus content was 38.7%, the pH value was 7.3, and the organic matter mass accounted for 43.6% on a dry weight basis. The total nutrients (N+P 2 O 5 +K 2The fermented product was sieved with a 1 mm pore size sieve to obtain a coarse-grained organic solid waste stabilization product A and a fine-grained organic solid waste stabilization product B.

[0074] The coarse-grained organic solid waste stabilization treatment product A was tested to have a moisture content of 45.9%, and the organic matter mass accounted for 51.2% on a dry weight basis. The fine-grained organic solid waste stabilization treatment product B was tested to have a moisture content of 29.1%, and more than 50% of the particle size was less than 0.3 mm. On a dry weight basis, the organic matter mass accounted for 27.8%.

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

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

[0077] Steel slag is the alkaline fine-grained smelting slag obtained by further grinding and screening the smelting waste of the smelter. The particle size is <200μm and it is rich in alkaline substances such as CaO, magnesium oxide, manganese oxide and iron and aluminum oxides (the total mass ratio of alkaline substances is 45.3%).

[0078] The microbial agent was a mixture of Bacillus subtilis and actinomycetes in a mass ratio of 1:1; Bacillus subtilis and actinomycetes were both conventional agents, and the number of viable bacteria was ≥1×10 10 cfu / g.

[0079] The cement is ordinary Portland cement.

[0080] Plant seeds A are prepared by mixing Cynodon dactylon and Achnatherum splendens seeds in a mass ratio of 1:1.

[0081] Example 1

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

[0083] (1) Preparation of brick blanks: 30 parts of organic solid waste stabilization 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 brick blanks of 30 cm (length) × 10 cm (width) × 20 cm (height).

[0084] (2) Preparation of coating: 40 parts of organic solid waste stabilization 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 form a slurry. The slurry is evenly applied on the two sides of the length and height of the brick. The brick is pressed at 15 MPa using a brick press. The brick is 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) with a coating thickness of 1±0.3 cm.

[0085] Example 2

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

[0087] (1) Preparation of brick blanks: 25 parts of organic solid waste stabilization 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 a brick blank of 30 cm (length) × 10 cm (width) × 20 cm (height).

[0088] (2) Coating preparation: Add 50 parts of organic solid waste stabilization product B, 10 parts of fly ash, 5 parts of cement, and 0.6 parts of plant seeds, add an appropriate amount of water and mix them into mud. Apply the mud evenly on the two sides of the brick, which are the length and height. Use a brick press to press the bricks at a pressure of 15 MPa. Then, place the bricks 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 is 1±0.3 cm.

[0089] Example 3

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

[0091] (1) Preparation of brick blanks: 35 parts of organic solid waste stabilization 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 a brick blank of 30 cm (length) × 10 cm (width) × 20 cm (height).

[0092] (2) Preparation of coating: Add 30 parts of organic solid waste stabilization product B, 14 parts of fly ash, 8 parts of cement, and 0.3 parts of plant seeds, add appropriate amount of water and mix them into mud. Apply the mud evenly on the two sides of the brick, which are the length and height. Use a brick press to press the bricks at a pressure of 15 MPa. Then, place the bricks 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 is 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, which is different from Example 1 in that cement is not added during the preparation of the coating, as follows:

[0095] (1) Preparation of brick blanks: 30 parts of organic solid waste stabilization 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 brick blanks of 30 cm (length) × 10 cm (width) × 20 cm (height).

[0096] (2) Preparation of coating: 40 parts of organic solid waste stabilization product B, 12 parts of fly ash, and 0.5 parts of plant seeds are mixed with an appropriate amount of water to form a slurry. The slurry is evenly applied on the two sides of the length and height of the brick. A brick press is used to press the bricks at a pressure of 15 MPa. The bricks are 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 is 1±0.3 cm.

[0097] Comparative Example 2

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

[0099] After fully mixing 30 parts of organic solid waste stabilization 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) 10 pieces of sand barrier materials of the above-mentioned embodiment and comparative example were selected respectively, and their average masses were measured. Then, they were 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] It can be seen from Table 1 that the loss rate of the sand barrier materials prepared in the embodiments of the present invention is 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-mentioned embodiment and comparative example were laid in a test grid in the same area of ​​the desert in the form of 1.5m×1.5m. In spring, the same amount of sand barrier bricks (12g / m 2 ) of Achnatherum splendens seeds, and one year later, the average plant height in the grid, the biomass of all plants in the grid (i.e., total dry weight), 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 as 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, calculated on a dry weight basis, with an amount of 15% of the mass of municipal sludge) and fermented to obtain a stabilized organic solid waste product. The moisture content was 38.1%, the particle size was <3 cm, the humus content was 30.2%, the pH value was 6.8, the organic matter mass accounted for 35.2% on a dry weight basis, and the total nutrients (N+P 2 O 5 +K 2 O) accounts for 3.5% by mass. The above fermented products were sieved with a sieve with an aperture of 1 mm to obtain coarse-grained organic solid waste stabilization product A and fine-grained organic solid waste stabilization product B. The coarse-grained organic solid waste stabilization product A was tested to have a moisture content of 41.3%, and the mass proportion of organic matter was 40.9% on a dry weight basis. The fine-grained organic solid waste stabilization product B was tested to have a moisture content of 32.2%, 62.7% of the particle size was less than 0.3 mm, and the mass proportion of organic matter was 24.2% on a dry weight basis. The remaining raw materials are the same as those in the above embodiment.

[0111] The sand barrier material (mud brick) prepared by the above raw materials according to the method described in Example 1 was laid in parallel horizontally and vertically, with a spacing of 1.5m between each row horizontally and vertically, and two adjacent mud bricks were closely adjacent to each other, and the bricks were partially buried in the sand, with a burial depth of 5cm. They were artificially laid as mud square sand barriers, and the organic matter content of the sand on the surface of the square (mixed at a depth of 10cm) was 0.68%. After the laying was completed, Achnatherum splendens coated seeds were sown in the mud square. After 3 months, the green coverage rate in the square was 61%, and after 1 year, the green coverage rate in the square was 93%. At this time, the organic matter content of the surface sand (mixed at a depth of 10cm) was 1.54%.

[0112] Sand control application 2:

[0113] Municipal sludge with a moisture content of 70.3% was mixed with auxiliary materials (crushed garden waste and straw, calculated on a dry weight basis, with an amount of 20% of the municipal sludge mass) and subjected to aerobic fermentation treatment to obtain a stabilized organic solid waste product. The moisture content was 42.2%, the particle size was <3 cm, the humus content was 40.3%, the pH value was 7.1, the organic matter mass accounted for 48.5% on a dry weight basis, and the total nutrients (N+P 2 O 5 +K 2 O) accounts for 4.3% by mass. The above fermented products were sieved with a sieve with an aperture of 1 mm to obtain coarse-grained organic solid waste stabilization product A and fine-grained organic solid waste stabilization product B. The coarse-grained organic solid waste stabilization product A was tested to have a moisture content of 47.6%, and on a dry weight basis, the mass proportion of organic matter was 55.3%. The fine-grained organic solid waste stabilization product B was tested to have a moisture content of 27.8%, 58.1% of the particle size was less than 0.3 mm, and on a dry weight basis, the mass proportion of organic matter was 29.5%. The remaining raw materials are the same as those in the above embodiment.

[0114] The above raw materials were prepared into sand barrier materials (mud bricks) according to the method described in Example 1, and they were laid in parallel horizontally and vertically, with a spacing of 2m between each row horizontally and vertically, and a gap of 2cm between two adjacent mud bricks. The bricks were directly placed on the surface of the sand and artificially laid into mud grid sand barriers. The organic matter content of the sand on the surface layer (10cm depth mixed) in the grid was 0.68%. After the laying was completed, coated seeds of Achnatherum splendens were sown in the mud grid. After 3 months, the green coverage rate in the grid was 58%, and after 1 year, the green coverage rate in the grid was 91%. At this time, the organic matter content of the surface sand (10cm depth mixed) was 1.27%.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

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 brick is pressed from the following raw materials, which are calculated by weight and include 20-40 parts of organic solid waste stabilized product A, 5-10 parts of phosphogypsum, 10-15 parts of fly ash, 10-15 parts of steel slag, and 0.1-1 parts of microbial agent; The coating is prepared from a slurry formed by mixing the following raw materials with water, wherein the raw materials, by weight, include 30-50 parts of organic solid waste stabilized 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, and has a moisture content of 35-45%, a particle size of <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 accounts for 30-50%, and the total nutrient mass accounts for >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 accounts for 40-60% based on the dry weight of the organic solid waste stabilization product A; 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%, and the organic matter mass accounts for 20-30% based on the dry weight of the organic solid waste stabilization 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, with 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% of the particle size is 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 from 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 (20-50cm)×(5-15cm)×(15-30cm).

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, 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 sphaerocephala, Achnatherum splendens, Cynodon dactylon, Lolium perenne and Staphlomis sphaerocephala.

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 treatment product to obtain a coarse-grained organic solid waste stabilization treatment product A and a fine-grained organic solid waste stabilization treatment product B; S2, mixing the organic solid waste stabilization treatment product A, phosphogypsum, fly ash, steel slag and microbial agent, and pressing to obtain a brick; S3, the slurry obtained by mixing the organic solid waste stabilization 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 water content of the mud is 70-85%, the re-compression pressure is 10-20Mpa, and the curing time is 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 described in any one of claims 1 to 7 or the sand barrier material prepared by the preparation method described in 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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