A method for preparing ecological slope protection materials by mixing biochar with multi-source solid waste

Abstract

The invention discloses a method for preparing ecological slope protection materials by adding biochar to multi-source solid wastes. The method comprises the following steps: pre-soaking the biochar obtained by pyrolysis, fully stirring saturated biochar particles, red mud powder, phosphogypsum powder, blast furnace slag particles, blast furnace slag powder, an activator and a foaming agent to prepare slurry, and then forming and curing the slurry according to the requirements of the slope protection project to prepare ecological slope protection water-permeable materials in various shapes. The method can convert biochar, red mud, phosphogypsum and blast furnace slag into cheap ecological slope protection materials with good water permeability, mechanical strength and low leaching properties, and realize large-scale disposal and resource utilization of bulk industrial solid wastes such as red mud, phosphogypsum and blast furnace slag.

Description

Technical Field

[0001] The invention relates to a method for preparing an ecological slope protection material by adding biochar into multi-source solid waste, and belongs to the field of ecological environment protection and solid waste resource utilization. Background Art

[0002] There is a lot of excavation in the construction of water conservancy, highways, railways, mining and other projects. Excavation causes serious damage to the original vegetation, forming a large number of exposed soil slopes and rock slopes, leading to serious ecological imbalance, such as soil erosion, landslides, mudslides, light and sound pollution, and destruction of the food chain. It often takes a long time for the slopes formed by these projects to restore the ecological balance by the power of nature itself. Although the soil slope can achieve ecological restoration in a relatively short time through artificial protection and greening, it is difficult to restore the original vegetation. With the strengthening of my country's economic strength and the improvement of people's environmental awareness, more and more attention has been paid to the protection and research of the ecological environment. In traditional slope protection projects, excessive use of hard materials such as mortar block stone and concrete is prone to internal instability, soil erosion, slope cracking and other problems, thereby affecting the overall structural stability of the slope protection, construction costs, and destroying the biological living environment and species diversity.

[0003] At present, there are few studies on the preparation of ecological slope protection materials by adding biochar to multi-source solid waste. In addition, due to the complexity of the composition of multi-source solid waste, the amount used is usually not very high. Not only can it not meet the requirements of the "three transformations" principle of solid waste, but it also cannot meet environmental requirements. Summary of the invention

[0004] In order to alleviate the problems of high stockpiles, low utilization rates and poor gelling activity of red mud, phosphogypsum and blast furnace slag, the present invention provides a method for preparing ecological slope protection materials by adding biochar to multi-source solid wastes, and optimizes red mud, phosphogypsum and blast furnace slag with biochar, activators and chemical foaming agents, providing a new method for the resource utilization of red mud, phosphogypsum and blast furnace slag, while achieving certain permeability, durability and environmental protection while reducing production costs.

[0005] The present invention mixes biochar into red mud, phosphogypsum and blast furnace slag with gelling activity, and adds an activator and a chemical foaming agent to prepare an ecological slope protection material. The red mud, phosphogypsum and blast furnace slag are rich in active ingredients such as SiO2, CaO, Al2O3, etc., which have the potential to be used as slope protection materials. When the activator is added, the red mud can be promoted to release more active substances, and the presence of the chemical foaming agent can make the mixture form a porous structure. The material not only has the excellent performance of concrete but also has the function of promoting plant growth, which is similar to adding the potential of vegetation slope protection to traditional slope protection materials.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing ecological slope protection materials by adding biochar to multi-source solid waste, the specific steps are as follows:

[0008] (1) crushing and drying the biomass, pyrolyzing it, grinding it and passing it through a 100-300 mesh sieve to obtain biochar;

[0009] (2) drying, grinding and sieving red mud, phosphogypsum and blast furnace slag respectively to obtain red mud powder, phosphogypsum powder, blast furnace slag particles and blast furnace slag powder;

[0010] (3) pre-soaking the biochar particles obtained in step (1) to a saturated state to obtain saturated biochar;

[0011] (4) The red mud powder, phosphogypsum powder, blast furnace slag particles, and blast furnace slag powder obtained in step (2) are mixed and then mixed with the saturated biochar obtained in step (3), and water, an activator, and a foaming agent are added to the solid mixture, and the mixture is fully stirred to obtain an ecological slope protection material.

[0012] The biomass in step (1) is one or more of tobacco waste, wood chips, coffee grounds, and corn stalks mixed in any proportion; the drying condition is drying at 105-120° C. for 24-48 hours; and the pyrolysis is carried out in a nitrogen atmosphere, heating to 300-600° C. at a heating rate of 5-10° C. / min and then pyrolyzing at a constant temperature for 2-4 hours.

[0013] The drying in step (2) is to dry the red mud, phosphogypsum and blast furnace slag in an electric constant temperature blast drying oven, respectively, and the red mud, phosphogypsum and blast furnace slag are dried in an electric constant temperature blast drying oven, respectively, wherein the drying temperature is 105-150°C.

[0014] The grinding and screening in step (2) is that the blast furnace slag is passed through a 20-40 mesh sieve to obtain blast furnace slag particles, and the red mud, phosphogypsum and blast furnace slag are passed through a 60-100 mesh sieve to obtain red mud powder, phosphogypsum powder and blast furnace slag powder.

[0015] The pre-soaking in step (3) is to mix the biochar particles and water in a mass ratio of 1:100 and then stir at 20±2°C for 6 to 8 hours.

[0016] The mass ratio of the red mud powder, phosphogypsum powder, blast furnace slag particles, blast furnace slag powder and saturated biochar particles in step (4) is 1-3:1-3:1-2:0.1-1:0.1-1.

[0017] The activator in step (4) is water glass with a modulus of 1.0 to 1.5, and the amount used is 5 to 10% of the mass of the solid mixture.

[0018] The foaming agent in step (4) is aluminum powder, aluminum hydroxide, etc. specially used for concrete, and the amount used is 1 to 3% of the mass of the solid mixture.

[0019] The amount of water used in step (4) is 40-60% of the mass of the solid mixture.

[0020] The stirring process in step (4) is under room temperature, the rotation speed is 300-450 rpm, and the stirring time is 10-20 min.

[0021] The red mud of the present invention is alkaline solid waste, phosphogypsum is acidic solid waste, the composition of blast furnace slag is similar to cement, and the biochar pyrolyzed at above 300°C is weakly alkaline and has excellent water retention capacity and adsorption performance. Combining the four to prepare ecological slope protection materials can not only ensure that the product is a neutral product, but also meet environmental standards.

[0022] The beneficial effects of the present invention are as follows:

[0023] (1) The water permeability coefficient of the ecological slope protection material obtained by the present invention is greater than 1 cm / s, the compressive strength is between 30 and 48 MPs, and the fluoride leaching concentration reaches the groundwater Class 3 standard.

[0024] (2) The present invention can dispose of red mud, phosphogypsum and blast furnace slag to the greatest extent, providing a new idea for the resource utilization of solid waste and the reduction of environmental pollution caused by the storage of pollutants.

[0025] (3) The present invention uses multi-source solid waste to prepare ecological slope protection materials, which not only reduces process costs, but also is simple to operate and convenient for large-scale use. Compared with existing ecological coagulant materials and their preparation methods, the present invention has lower costs and simpler operations. While meeting the requirements of slope protection permeable materials, the addition of biochar provides an excellent matrix for the rapid growth of organisms in the slope protection body, and improves the air permeability and water permeability. The present invention not only realizes the resource utilization of multi-source solid waste and biomass carbon fixation, but also achieves the purpose of reducing slope protection costs and improving benefits. It meets the strategic needs of synergistic efficiency of pollution reduction and carbon reduction, and produces good economic, social and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a process flow chart of the present invention;

[0027] Figure 2 is the XRD pattern of red mud powder;

[0028] Figure 3 is the XRD pattern of phosphogypsum powder;

[0029] Figure 4 XRD diagram of ecological slope protection materials;

[0030] Figure 5 Water permeability graph of Examples 1-5 and Comparative Example 1;

[0031] Figure 6Fluoride leaching concentration diagram of Examples 1-5 and Comparative Example 1;

[0032] Figure 7 Compressive strength diagram of Examples 1-5 and Comparative Example 1. DETAILED DESCRIPTION

[0033] In conjunction with the following examples, the present invention is further described in detail. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially. The water glass used in the embodiments of the present invention was purchased from Henan Borun Casting Material Co., Ltd., which is a transparent liquid water glass, and its model is BR2481.

[0034] Example 1

[0035] A method for preparing ecological slope protection materials by adding biochar to multi-source solid waste, such as Figure 1 As shown, the following steps are included:

[0036] (1) Tobacco waste from a tobacco company in Kunming, Yunnan Province was crushed and dried in an electric constant temperature forced air drying oven at 105°C for 24 h, then placed in a tubular furnace, heated to 300°C at a heating rate of 5°C / min in a nitrogen atmosphere, and pyrolyzed for 2 h. The biochar was ground in an agate mortar and passed through a 100-mesh sieve to obtain biochar for later use;

[0037] (2) The Bayer red mud produced by an aluminum company in Wenshan Prefecture, Yunnan Province was dried in an electric constant temperature blast drying oven at 105°C for 24 hours, and ground with an agate mortar and passed through a 60-mesh sieve to obtain red mud powder for later use;

[0038] (3) drying the phosphogypsum produced by a phosphogypsum company in Kunming, Yunnan Province at 105° C. for 24 h in an electric constant temperature blast drying oven, and grinding the phosphogypsum powder with an agate mortar to obtain a 60-mesh powder for later use;

[0039] (4) Blast furnace slag produced by a pig iron smelting company in Yunnan Province was dried in an electric constant temperature blast drying oven at 105° C. for 24 h, ground with an agate mortar and sieved through a 20-mesh sieve to obtain blast furnace slag particles for later use;

[0040] (5) Blast furnace slag produced by a pig iron smelting company in Yunnan Province was dried in an electric constant temperature blast drying oven at 105° C. for 24 h, ground with an agate mortar and sieved through a 60-mesh sieve to obtain blast furnace slag powder for later use;

[0041] (6) The biochar obtained in step (1) and water are placed in a beaker at a mass ratio of 1:100, stirred on a magnetic stirrer at 20±2°C for 6 h, and filtered with a vacuum pump filtration device under a 0.45 μm microporous filter membrane until all the soaked biochar is collected in the wet filter paper to obtain saturated biochar particles;

[0042] (7) The red mud powder obtained in step (2), the phosphogypsum powder obtained in step (3), the blast furnace slag particles obtained in step (4), the blast furnace slag powder obtained in step (5), and the saturated biochar particles in step (6) are mixed in a mass ratio of 1:1:1:0.1:0.1, and water, an activator water glass (1.0 modulus) and a chemical foaming agent special aluminum powder for concrete are added to the obtained solid mixture, wherein the amount of water used is 40% of the mass of the solid mixture, the amount of water glass used is 5% of the mass of the solid mixture, and the amount of special aluminum powder used for concrete is 1% of the mass of the solid mixture. The obtained mixture is placed in a stirrer at a rotation speed of 300 rpm at room temperature and stirred for 10 minutes to obtain an ecological slope protection material.

[0043] Example 2

[0044] A method for preparing ecological slope protection materials by adding biochar to multi-source solid wastes comprises the following steps:

[0045] (1) Tobacco waste from a tobacco company in Kunming, Yunnan Province was crushed and dried in an electric constant temperature forced air drying oven at 110°C for 36 h, then placed in a tubular furnace, heated to 400°C at a heating rate of 7°C / min in a nitrogen atmosphere, and pyrolyzed at this temperature for 3 h. The biochar was ground in an agate mortar and sieved through a 200-mesh sieve to obtain biochar for later use;

[0046] (2) The Bayer red mud produced by an aluminum company in Wenshan Prefecture, Yunnan Province was dried in an electric constant temperature blast drying oven at 125°C for 36 hours, and then ground with an agate mortar and sieved through an 80-mesh sieve to obtain red mud powder for later use;

[0047] (3) drying the phosphogypsum produced by a phosphogypsum company in Kunming, Yunnan Province at 120° C. for 36 h in an electric constant temperature blast drying oven, and grinding the phosphogypsum powder with an agate mortar to obtain 80 meshes for later use;

[0048] (4) Blast furnace slag produced by a pig iron smelting company in Yunnan Province was dried in an electric constant temperature blast drying oven at 125° C. for 24 h, ground with an agate mortar and sieved through a 30-mesh sieve to obtain blast furnace slag particles for later use;

[0049] (5) Blast furnace slag produced by a pig iron smelting company in Yunnan Province was dried in an electric constant temperature blast drying oven at 125° C. for 36 h, and ground with an agate mortar and sieved through an 80-mesh sieve to obtain blast furnace slag powder for later use;

[0050] (6) The biochar obtained in step (1) and water are placed in a beaker at a ratio of 1:100, stirred on a magnetic stirrer at 20±2°C for 7 h, and filtered with a vacuum pump under a 0.45 μm microporous filter membrane until all the soaked biochar is collected in the wet filter paper to obtain saturated biochar particles;

[0051] (7) The red mud powder obtained in step (2), the phosphogypsum powder obtained in step (3), the blast furnace slag particles obtained in step (4), the blast furnace slag powder obtained in step (5), and the saturated biochar particles obtained in step (6) are mixed in a ratio of 2:2:1.5:0.5:0.5, and water, an activator water glass (1.25 modulus) and a chemical foaming agent concrete-specific aluminum powder are added to the obtained solid mixture, wherein the amount of water used is 50% of the total mass of the solid mixture, the amount of water glass used is 7.5% of the total mass of the solid mixture, and the amount of concrete-specific aluminum powder used is 2% of the total mass of the solid mixture. The obtained mixture is placed in a stirrer at a rotation speed of 375 rpm at room temperature and stirred for 15 minutes to obtain a composite cementitious material.

[0052] Example 3

[0053] A method for preparing ecological slope protection materials by adding biochar to multi-source solid wastes comprises the following steps:

[0054] (1) Tobacco waste from a tobacco company in Kunming, Yunnan Province was crushed and dried in an electric constant temperature forced air drying oven at 120°C for 48 h, then placed in a tubular furnace, heated to 500°C at a heating rate of 10°C / min in a nitrogen atmosphere, and pyrolyzed at this temperature for 4 h. The biochar was ground in an agate mortar and sieved through a 300-mesh sieve to obtain biochar for later use;

[0055] (2) The Bayer red mud produced by an aluminum company in Wenshan Prefecture, Yunnan Province was dried in an electric constant temperature blast drying oven at 150° C. for 48 h, and ground with an agate mortar and sieved through a 100-mesh sieve to obtain red mud powder for later use;

[0056] (3) drying the phosphogypsum produced by a phosphogypsum company in Kunming, Yunnan Province at 150° C. for 48 h in an electric constant temperature blast drying oven, and grinding the phosphogypsum powder with an agate mortar to obtain 100 mesh;

[0057] (4) Blast furnace slag produced by a pig iron smelting company in Yunnan Province was dried in an electric constant temperature blast drying oven at 150° C. for 48 h, and ground with an agate mortar and sieved through a 40-mesh sieve to obtain blast furnace slag particles for later use;

[0058] (5) Blast furnace slag produced by a pig iron smelting company in Yunnan Province was dried in an electric constant temperature blast drying oven at 150° C. for 48 h, and ground with an agate mortar and sieved through a 100-mesh sieve to obtain blast furnace slag powder for later use;

[0059] (6) The biochar obtained in step (1) and water are placed in a beaker at a mass ratio of 1:100, stirred on a magnetic stirrer at 20±2°C for 8 h, and filtered with a vacuum pump under a 0.45 μm microporous filter membrane until all the soaked biochar is collected in the wet filter paper to obtain saturated biochar particles;

[0060] (7) The red mud powder obtained in step (2), the phosphogypsum powder obtained in step (3), the blast furnace slag particles obtained in step (4), the blast furnace slag powder obtained in step (5), and the saturated biochar particles obtained in step (5) are mixed in a mass ratio of 3:3:2:1:1, and water, an activator water glass (1.25 modulus) and a chemical foaming agent concrete-specific aluminum powder are added to the obtained solid mixture, wherein the amount of water used is 60% of the mass of the solid mixture, the amount of water glass used is 10% of the mass of the solid mixture, and the amount of concrete-specific aluminum powder used is 3% of the mass of the solid mixture. The obtained mixture is placed in a stirrer at a rotation speed of 450 rpm at room temperature and stirred for 20 minutes to obtain an ecological slope protection material.

[0061] Example 4

[0062] A method for preparing ecological slope protection materials by adding biochar to multi-source solid wastes comprises the following steps:

[0063] (1) Tobacco waste from a tobacco company in Kunming, Yunnan Province was crushed and dried in an electric constant temperature forced air drying oven at 105°C for 48 h, then placed in a tubular furnace and heated to 600°C at a heating rate of 5°C / min in a nitrogen atmosphere for constant temperature pyrolysis for 2 h, and ground in an agate mortar through a 200-mesh sieve to obtain biochar for use;

[0064] (2) The Bayer red mud produced by an aluminum company in Wenshan Prefecture, Yunnan Province was dried in an electric constant temperature blast drying oven at 105°C for 48 hours, and ground with an agate mortar and passed through a 60-mesh sieve to obtain red mud powder for later use;

[0065] (3) drying the phosphogypsum produced by a phosphogypsum company in Kunming, Yunnan Province at 150° C. for 24 h in an electric constant temperature blast drying oven, and grinding the phosphogypsum powder with an agate mortar to obtain 60 meshes for later use;

[0066] (4) Blast furnace slag produced by a pig iron smelting company in Yunnan Province was dried in an electric constant temperature blast drying oven at 105° C. for 48 h, and ground with an agate mortar and passed through a 20-mesh sieve to obtain blast furnace slag particles for later use;

[0067] (5) Blast furnace slag produced by a pig iron smelting company in Yunnan Province was dried in an electric constant temperature blast drying oven at 105° C. for 48 h, and ground with an agate mortar and passed through a 60-mesh sieve to obtain blast furnace slag powder for later use;

[0068] (6) The biochar obtained in step (1) and water are placed in a beaker at a mass ratio of 1:100, stirred on a magnetic stirrer at 20±2°C for 6 h, and filtered with a vacuum pump under a 0.45 μm microporous filter membrane until all the soaked biochar is collected in the wet filter paper to obtain saturated biochar particles;

[0069] (7) The red mud powder obtained in step (2), the phosphogypsum powder obtained in step (3), the blast furnace slag particles obtained in step (4), the blast furnace slag particles obtained in step (5), and the saturated biochar particles obtained in step (6) are mixed in a mass ratio of 2:2:1.5:0.5:0.5, and water, an activator water glass (1.5 modulus) and a chemical foaming agent concrete-specific aluminum powder are added to the obtained solid mixture, wherein the amount of water used is 40% of the mass of the solid mixture, the amount of water glass used is 5% of the mass of the solid mixture, and the amount of concrete-specific aluminum powder used is 3% of the mass of the solid mixture. The obtained mixture is placed in a stirrer at a rotation speed of 350 rpm at room temperature and stirred for 10 minutes to obtain an ecological slope protection material.

[0070] Example 5

[0071] A method for preparing ecological slope protection materials by adding biochar to multi-source solid wastes comprises the following steps:

[0072] (1) Coffee grounds from a coffee production plant in Kunming, Yunnan Province were crushed and dried in an electric constant temperature forced air drying oven at 110°C for 36 h, then placed in a tubular furnace and heated to 400°C at a heating rate of 7°C / min in a nitrogen atmosphere for constant temperature pyrolysis for 3 h, and ground in an agate mortar through a 200-mesh sieve to obtain biochar for use;

[0073] (2) The Bayer red mud produced by an aluminum company in Wenshan Prefecture, Yunnan Province was dried in an electric constant temperature blast drying oven at 125°C for 36 hours, and then ground with an agate mortar and sieved through an 80-mesh sieve to obtain red mud powder for later use;

[0074] (3) drying the phosphogypsum produced by a phosphogypsum company in Kunming, Yunnan Province at 120° C. for 36 h in an electric constant temperature blast drying oven, and grinding the phosphogypsum powder with an agate mortar to obtain 80 meshes for later use;

[0075] (4) Blast furnace slag produced by a pig iron smelting company in Yunnan Province was dried in an electric constant temperature blast drying oven at 125° C. for 24 h, ground with an agate mortar and sieved through a 30-mesh sieve to obtain blast furnace slag particles for later use;

[0076] (5) Blast furnace slag produced by a pig iron smelting company in Yunnan Province was dried in an electric constant temperature blast drying oven at 125° C. for 36 h, and ground with an agate mortar and sieved through an 80-mesh sieve to obtain blast furnace slag powder for later use;

[0077] (6) The biochar obtained in step (1) and water are placed in a beaker at a ratio of 1:100, stirred on a magnetic stirrer at 20±2°C for 7 h, and filtered with a vacuum pump under a 0.45 μm microporous filter membrane until all the soaked biochar is collected in the wet filter paper to obtain saturated biochar particles;

[0078] (7) The red mud powder obtained in step (2), the phosphogypsum powder obtained in step (3), the blast furnace slag particles obtained in step (4), the blast furnace slag powder obtained in step (5), and the saturated biochar particles obtained in step (6) are mixed in a ratio of 2:2:1.5:0.5:0.5, and water, an activator water glass (1.25 modulus) and a foaming agent aluminum hydroxide are added to the obtained solid mixture, wherein the amount of water used is 50% of the total mass of the solid mixture, the amount of water glass used is 7.5% of the total mass of the solid mixture, and the amount of aluminum hydroxide used is 2% of the total mass of the solid mixture. The obtained mixture is placed in a stirrer at a rotation speed of 375 rpm at room temperature and stirred for 15 minutes to obtain an ecological slope protection material.

[0079] Comparative Example 1

[0080] The raw materials and conditions in the preparation process of this embodiment are the same as those in Example 1, except that no biochar is added. The specific steps are as follows:

[0081] (1) The Bayer red mud produced by an aluminum company in Wenshan Prefecture, Yunnan Province was dried in an electric constant temperature blast drying oven at 105°C for 24 hours, and ground with an agate mortar and passed through a 60-mesh sieve to obtain red mud powder for later use;

[0082] (2) drying the phosphogypsum produced by a phosphogypsum company in Kunming, Yunnan Province at 105° C. for 24 h in an electric constant temperature blast drying oven, and grinding the phosphogypsum powder with an agate mortar to obtain a 60-mesh powder for later use;

[0083] (3) Blast furnace slag produced by a pig iron smelting company in Yunnan Province was dried in an electric constant temperature blast drying oven at 105° C. for 24 h, ground with an agate mortar and sieved through a 20-mesh sieve to obtain blast furnace slag particles for later use;

[0084] (4) Blast furnace slag produced by a pig iron smelting company in Yunnan Province was dried in an electric constant temperature blast drying oven at 105° C. for 24 h, ground with an agate mortar and sieved through a 60-mesh sieve to obtain blast furnace slag powder for later use;

[0085] (5) The red mud powder obtained in step (1), the phosphogypsum powder obtained in step (2), the blast furnace slag particles obtained in step (3), and the blast furnace slag powder obtained in step (4) are mixed in a mass ratio of 1:1:1:0.1, and water, an activator water glass, and a foaming agent aluminum powder are added to the obtained solid mixture, wherein the amount of water used is 40% of the total mass of the solid mixture, the amount of water glass (1.0 modulus) used is 5% of the total mass of the solid mixture, and the amount of aluminum powder used is 1% of the total mass of the solid mixture. The obtained mixture is placed in a stirrer at a rotation speed of 300 rpm at room temperature and stirred for 10 minutes to obtain an ecological slope protection material.

[0086] Figure 2 is the XRD pattern of the red mud powder obtained in Example 1, Figure 3 is the XRD diagram of phosphogypsum powder. Figure 4 XRD diagram of ecological slope protection materials. It can be seen from the figure that red mud and phosphogypsum contain certain active components that can promote hydration reaction to generate hydration products.

[0087] The ecological slope protection materials prepared in Examples 1 to 5 and Comparative Example 1 are mainly in the form of slurry and can be prepared into various styles according to the requirements of the slope protection project. The slurry is poured into a Φ50×50mm mold, and demolded after standing at room temperature for 24 hours to obtain a cylindrical test block. The test block is cured under standard curing conditions, and the compressive strength of the test block is measured at 7 days, 14 days, and 28 days. At the same time, on the 28th day, the water tank method and the solid waste leaching method ("Solid Waste Toxic Leaching Method Reversal Method" (GB5086.1-1997) and GB / T 7484-1987 "Determination of Fluoride in Water Quality Ion Selective Electrode Method") are used to test the water permeability coefficient and fluoride leaching concentration of the test block. The test data are shown in Table 1.

[0088] Table 1

[0089]

[0090] From Table 1 and Figure 5-7 It can be seen that the ecological slope protection material prepared from biochar, red mud, phosphogypsum and blast furnace slag has good water permeability, mechanical strength and low fluoride leaching concentration, which can not only meet the needs of various slope protection projects but also meet environmental requirements. By comparison, it can be seen that the changes in water permeability, fluoride leaching concentration and compressive strength of the ecological slope protection material are related to the addition of biochar, and the performance of the material is better after adding biochar.

[0091] The above descriptions are only some preferred embodiments of the present invention and are not intended to limit the present invention. For ordinary technicians in this field, as long as they are within the concept and principle of the present invention, there may be various modifications and changes, which all belong to the protection scope of the present invention.

Claims

1. A method for preparing ecological slope protection materials by adding biochar to multi-source solid waste, characterized in that: The specific steps are as follows: (1) crushing and drying the biomass, pyrolyzing it, grinding it and passing it through a 100-300 mesh sieve to obtain biochar; (2) drying, grinding and sieving red mud, phosphogypsum and blast furnace slag respectively to obtain red mud powder, phosphogypsum powder, blast furnace slag particles and blast furnace slag powder; The sieving is to pass the blast furnace slag through a 20-40 mesh sieve to obtain blast furnace slag particles, and pass the red mud, phosphogypsum, and blast furnace slag through a 60-100 mesh sieve to obtain red mud powder, phosphogypsum powder, and blast furnace slag powder; (3) pre-soaking the biochar particles obtained in step (1) to a saturated state to obtain saturated biochar; (4) The red mud powder, phosphogypsum powder, blast furnace slag particles, and blast furnace slag powder obtained in step (2) are mixed and then mixed with the saturated biochar obtained in step (3), and water, an activator, and a foaming agent are added to the solid mixture, and stirred to obtain an ecological slope protection material; the mass ratio of the red mud powder, phosphogypsum powder, blast furnace slag particles, blast furnace slag powder, and saturated biochar is 1-3:1-3:1-2:0.1-1:0.1-1.

2. The method for preparing ecological slope protection materials by adding biochar to multi-source solid waste according to claim 1, characterized in that: The biomass in step (1) is one or a mixture of any proportion of tobacco waste, wood chips, coffee grounds, and corn stalks.

3. The method for preparing ecological slope protection materials by adding biochar to multi-source solid waste according to claim 1, characterized in that: The drying in step (1) is performed at 105-120° C. for 24-48 hours; the pyrolysis is performed in a nitrogen atmosphere, heating the temperature to 300-600° C. at a heating rate of 5-10° C. / min and then pyrolyzing at a constant temperature for 2-4 hours.

4. The method for preparing ecological slope protection materials by adding biochar to multi-source solid waste according to claim 1, characterized in that: The pre-soaking in step (3) is to mix the biochar particles and water in a mass ratio of 1:100 and then stir at 20° C. for 6 to 8 hours.

5. The method for preparing ecological slope protection materials by adding biochar to multi-source solid waste according to claim 1, characterized in that: The activator in step (4) is water glass with a modulus of 1.0 to 1.5, and the amount used is 5 to 10% of the mass of the solid mixture.

6. The method for preparing ecological slope protection materials by adding biochar to multi-source solid waste according to claim 1, characterized in that: The foaming agent in step (4) is aluminum powder or aluminum hydroxide specially used for concrete, and the amount used is 1 to 3% of the mass of the solid mixture.

7. The method for preparing ecological slope protection materials by adding biochar to multi-source solid waste according to claim 1, characterized in that: The amount of water in step (4) is 40-60% of the mass of the solid mixture.

8. The method for preparing ecological slope protection materials by adding biochar to multi-source solid waste according to claim 1, characterized in that: The stirring in step (4) is carried out at room temperature, with a rotation speed of 300 to 450 rpm and stirring for 10 to 20 minutes.

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