A vertical anti-fouling barrier material and its preparation method and application

Abstract

The present invention belongs to the technical field of vertical barrier materials, and specifically relates to a vertical anti-pollution barrier material, its preparation method, and application, wherein the anti-pollution barrier material comprises the following components in parts by mass: 10 to 15 parts of bentonite, 3 to 15 parts of gelling agent, and 70 to 87 parts of in-situ soil, wherein the gelling agent comprises activated red mud, blast furnace slag powder, silica fume, and water glass. By using the gelling agent component instead of cement, the adsorption capacity, pollution interception capacity, and early strength of the vertical anti-pollution barrier material are improved, and the material can form a low-permeability anti-pollution barrier in high-concentration organic and heavy metal contaminated solutions, blocking the horizontal migration of pollutants with groundwater, thereby achieving effective isolation and control of contaminated sites. The vertical anti-pollution barrier material provided by the present invention can be used in contaminated sites where the concentration of heavy metals in groundwater is greater than or equal to 20 mg / L, or the concentration of organic matter is greater than or equal to 400 μg / L.

Description

Technical Field

[0001] The present invention belongs to the technical field of vertical barrier materials, and in particular relates to a vertical anti-fouling barrier material and a preparation method and application thereof. Background Art

[0002] In recent years, with the development of industrialization and urbanization, a large number of chemical companies have relocated from urban residential areas, leaving behind numerous industrially contaminated sites. At the same time, inadequate management at some active chemical plants has also led to varying degrees of pollution around their sites. Heavy metal and organic pollutants from these contaminated sites can be highly mobile as they flow through groundwater, necessitating the implementation of containment and control measures to minimize the safety risks posed to nearby residents and the surrounding environment.

[0003] Vertical barrier walls are a widely used risk control technology for contaminated sites. Although they cannot directly eliminate the source of pollution, they can effectively control the migration of pollutants within contaminated sites and reduce and eliminate the negative impacts of contaminated sites on human health and the surrounding environment. Vertical anti-pollution barriers can be divided into soil-bentonite, cement-bentonite, soil-cement-bentonite, cement concrete, sheet piles, and geomembrane-embedded vertical barriers based on material type. Vertical barriers containing bentonite, such as soil-cement-bentonite vertical isolation walls, are collectively referred to as bentonite-based vertical barrier walls. Due to their ease of construction and low cost, they are widely used in anti-seepage and anti-pollution projects at contaminated sites.

[0004] Bentonite is the primary functional material of bentonite-based barriers. Its main mineral component, montmorillonite, undergoes a strong volume expansion upon contact with water, blocking the pores through which contaminated groundwater can flow through the soil. High concentrations of heavy metals, organic contaminants, and acidic and alkaline solutions chemically erode the montmorillonite, significantly degrading its expansion properties. This results in the barrier failing to meet the permeability requirements of less than 1 × 10 m / s as stipulated in the "Technical Specifications for Geotechnical Engineering of Municipal Waste Sanitary Landfills" and the "Catalogue of Technologies for Remediation of Contaminated Sites (First Batch)." Therefore, the development of a vertical barrier material is urgently needed to overcome these limitations in practical applications. Summary of the Invention

[0005] In response to the problems mentioned in the background technology that the existing vertical barrier materials have poor chemical compatibility and are easily corroded and fail in high-concentration heavy metal and organic polluted groundwater, the present invention provides a vertical anti-pollution barrier material and its preparation method and method. By adding activated red mud, blast furnace slag powder, silica fume and water glass instead of cement to the gelling agent, the adsorption capacity and pollution interception capacity of the vertical anti-pollution barrier material are improved, and a low-permeability anti-pollution barrier can be formed in high-concentration organic pollution solutions and heavy metal pollution solutions, blocking the horizontal migration of pollutants with groundwater, thereby realizing effective isolation and control of contaminated sites.

[0006] In order to achieve the above-mentioned purpose, the present invention provides the following technical solution: a vertical anti-fouling barrier material, comprising the following components by mass fraction: 10 to 15 parts of bentonite, 3 to 15 parts of a gelling agent, and 70 to 87 parts of in-situ soil, wherein the gelling agent comprises activated red mud, blast furnace slag powder, silica fume and water glass.

[0007] Furthermore, the mass ratio of activated red mud, blast furnace slag powder, silica fume, and water glass in the gelling agent is 60-70:20-25:10-15:1-5. The mass ratio of activated red mud, blast furnace slag powder, silica fume, and water glass in the present invention directly affects the early strength and anti-seepage performance of the prepared vertical anti-fouling barrier material, and the above mass ratio is an optimal implementation range.

[0008] Furthermore, the particle size of the gelling agent is less than or equal to 0.075 mm, and the specific surface area of ​​the gelling agent is greater than or equal to 400 m 2 In the present invention, controlling the particle size of the gelling agent can effectively ensure the reaction activity and reaction efficiency of the gelling agent.

[0009] Furthermore, the bentonite is calcium-based bentonite or modified calcium-based bentonite, and the red mud is Bayer process red mud.

[0010] The present invention also provides a method for preparing a vertical anti-fouling barrier material, comprising the following steps:

[0011] Step 1: mixing red mud with alkali metal hydroxide or carbonate, calcining the mixture at high temperature, cooling and sieving to obtain activated red mud, then mixing the activated red mud with water glass, pre-treated granulated blast furnace slag powder, and silica fume in proportion to obtain a gelling agent, and mixing the gelling agent with water to obtain a gelling agent slurry;

[0012] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0013] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0014] Furthermore, in the step 1, the calcination temperature is 600-900° C., and the calcination time is 1-3 hours.

[0015] Furthermore, the pretreatment of the granulated blast furnace slag powder and silica fume in step 1 includes ball milling, drying and sieving, the ball milling time is 0.5 to 1 hour, the drying temperature is 100 to 110° C., and the sieve size is 200 mesh.

[0016] Furthermore, in the step 1, the gelling agent and water are mixed in a mass ratio of 1:3 to 1:6, the stirring time is 10 to 20 minutes, and the stirring speed is 1000 to 3000 rpm.

[0017] Furthermore, in the step 2, bentonite and water are mixed at a mass ratio of 1:10, the stirring time is 10 to 20 minutes, and the stirring speed is 1000 to 3000 rpm.

[0018] The present invention also provides an application of a vertical anti-pollution barrier material in a contaminated site where the concentration of heavy metals in groundwater is greater than or equal to 20 mg / L, or the concentration of organic matter is greater than or equal to 400 μg / L.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. To address the problems of existing vertical barrier materials, such as poor chemical compatibility and the susceptibility of bentonite minerals to corrosion in high-concentration heavy metal and organic contaminated solutions, leading to the failure of the anti-pollution barrier, the inventors innovatively replaced traditional cement with activated red mud, blast furnace slag powder, silica fume, and water glass as gelling agent components. Leveraging the strong adsorption capacity and low permeability of activated red mud, blast furnace slag powder, and silica fume, they enhance the vertical anti-pollution barrier material's ability to intercept pollutants. Together with bentonite, they provide a dual guarantee of interception, ensuring that the vertical barrier material of the present invention has a strong interception capacity in sites contaminated by high concentrations of heavy metals and organic matter. Furthermore, the particle size of the gelling agent is controlled by screening, ensuring its reactivity and efficiency.

[0021] 2. Since the gelled products of activated red mud, blast furnace slag powder, silica fume and water glass have a more uniform and dense structure than cement hydration products, they will not be corroded and rendered ineffective by high-concentration heavy metal and organic pollutant contaminated solutions; the alkaline substances produced by the gelling reaction of the former are less than those of the latter, which can reduce the dissolution of bentonite minerals in the alkaline environment. Therefore, the vertical barrier material of the present invention can still have strong stability in high-concentration heavy metal and organic contaminated solutions, thereby ensuring that it meets the permeability coefficient requirements of less than 1×10 -9 m / s requirement. On the other hand, the combination of activated red mud, blast furnace slag powder, silica fume, and water glass can produce early strength and durability superior to cement. This can further enhance the application of vertical anti-pollution barrier materials in polluted sites where production and management are simultaneously underway, strengthen the ability of vertical anti-pollution barriers to resist dry-wet cycles and freeze-thaw cycles, and improve their durability and service life.

[0022] 3. The main components used in the gelling agent of the present invention are products of solid waste resource utilization, especially red mud, granulated blast furnace slag and silica fume, which can not only alleviate the impact of solid waste on the environment, but also realize the resource utilization of solid waste, which is low-carbon and environmentally friendly.

[0023] 4. The preparation method provided by the present invention has simple process, low energy consumption, low engineering cost, and is easy to promote in engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a sample diagram of a vertical anti-fouling barrier material in the present invention. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is described in detail below through specific embodiments.

[0026] Example 1

[0027] This embodiment provides a vertical anti-fouling barrier material comprising bentonite, a gelling agent, and in-situ soil. The raw materials, by mass, are: 10% bentonite, 3% gelling agent, and 87% in-situ soil. The bentonite used in this embodiment is sodium-modified calcium-based bentonite. The gelling agent comprises activated red mud, granulated blast furnace slag powder, silica fume, and water glass, in a mass ratio of 70:20:10:1.

[0028] This embodiment also provides a method for preparing a vertical anti-fouling barrier material, comprising the following steps:

[0029] Step 1: red mud and alkali metal hydroxide or carbonate are stirred and mixed, the mixture is calcined at high temperature, cooled and sieved to obtain activated red mud, and the activated red mud is then stirred and mixed with water glass, pre-treated granulated blast furnace slag powder, and silica fume in proportion to obtain a gelling agent, and the gelling agent is mixed and stirred with water to obtain a gelling agent slurry;

[0030] Specifically, Bayer process red mud is uniformly mixed with alkali metal hydroxide or carbonate, such as sodium hydroxide. The resulting mixture is calcined and activated at a temperature of 600°C for 1 hour, cooled, and sieved to obtain activated red mud. The activated red mud is then uniformly mixed with granulated blast furnace slag powder, silica fume, and water glass in a suitable proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled for 0.5 hours at a drying temperature of 105°C, using a 200 mesh screen, and then dried and sieved. The resulting gelling agent is then mixed with water in a mass ratio of 1:5 and stirred at 1000 rpm for 15 minutes to obtain a gelling agent slurry.

[0031] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0032] Specifically, calcium-based bentonite and water were mixed in a mass ratio of 1:10, and then stirred at a speed of 1000 rpm for 15 minutes to obtain bentonite slurry.

[0033] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0034] Specifically, the vertical barrier material is obtained by mixing the gelling agent slurry and bentonite slurry obtained in step 1 and step 2 with the in-situ soil according to the mass fractions of 10% bentonite, 3% gelling agent and 87% in-situ soil.

[0035] The vertical anti-pollution barrier material provided in this embodiment can be used to block contaminated sites left behind by relocated chemical companies where the heavy metal concentration in groundwater is greater than or equal to 20 mg / L.

[0036] Example 2

[0037] This embodiment provides a vertical anti-fouling barrier material comprising bentonite, a gelling agent, and in-situ soil. The raw materials, by mass, are: 15% bentonite, 15% gelling agent, and 70% in-situ soil. The bentonite used in this embodiment is sodium-modified calcium-based bentonite. The gelling agent comprises activated red mud, granulated blast furnace slag powder, silica fume, and water glass, in a mass ratio of 70:22:12:2.

[0038] This embodiment also provides a method for preparing a vertical anti-fouling barrier material, comprising the following steps:

[0039] Step 1: mixing red mud with alkali metal hydroxide or carbonate, calcining the mixture at high temperature, cooling and sieving to obtain activated red mud, then mixing the activated red mud with water glass, pre-treated granulated blast furnace slag powder, and silica fume in proportion to obtain a gelling agent, and mixing the gelling agent with water to obtain a gelling agent slurry;

[0040] Specifically, Bayer process red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the obtained mixture is calcined and activated at a calcination temperature of 800°C and a calcination time of 1.5 hours. The mixture is cooled and sieved to obtain activated red mud. The obtained activated red mud is uniformly mixed with granulated blast furnace slag powder, silica fume, and water glass in a proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill for 0.5 hours, dried, and sieved. The ball milling time is 105°C, and the drying temperature is 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:5, and stirred at 2000 rpm for 15 minutes to obtain a gelling agent slurry.

[0041] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0042] Specifically, calcium-based bentonite and water were mixed in a mass ratio of 1:10, and then stirred at a speed of 2000 rpm for 15 minutes to obtain bentonite slurry.

[0043] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0044] Specifically, the vertical barrier material is obtained by mixing the gelling agent slurry and bentonite slurry obtained in step 1 and step 2 with the in-situ soil according to the mass fractions of 15% bentonite, 15% gelling agent and 70% in-situ soil.

[0045] The vertical anti-pollution barrier material can be used to block polluted sites of operating chemical enterprises where the heavy metal concentration in groundwater is greater than or equal to 20 mg / L.

[0046] Example 3

[0047] This embodiment provides a vertical anti-fouling barrier material comprising bentonite, a gelling agent, and in-situ soil. The raw materials, by mass, are: 10% bentonite, 3% gelling agent, and 87% in-situ soil. The bentonite used in this embodiment is sodium-modified calcium-based bentonite. The gelling agent comprises activated red mud, granulated blast furnace slag powder, silica fume, and water glass, in a mass ratio of 68:22:10:3.

[0048] This embodiment also provides a method for preparing a vertical anti-fouling barrier material, comprising the following steps:

[0049] Step 1: mixing red mud with alkali metal hydroxide or carbonate, calcining the mixture at high temperature, cooling and sieving to obtain activated red mud, then mixing the activated red mud with water glass, pre-treated granulated blast furnace slag powder, and silica fume in proportion to obtain a gelling agent, and mixing the gelling agent with water to obtain a gelling agent slurry;

[0050] Specifically, Bayer process red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the resulting mixture is calcined and activated at a calcination temperature of 700°C for 2.5 hours. The mixture is cooled and sieved to obtain activated red mud. The obtained activated red mud is uniformly mixed with granulated blast furnace slag powder, silica fume, and water glass in a proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill for 0.5 hours, dried at a drying temperature of 105°C, and screened with a sieve size of 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:4 and stirred at 2500 rpm for 15 minutes to obtain a gelling agent slurry.

[0051] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0052] Specifically, calcium-based bentonite and water were mixed in a mass ratio of 1:10, and then stirred at a speed of 2500 rpm for 15 minutes to obtain bentonite slurry.

[0053] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0054] Specifically, the vertical barrier material is obtained by mixing the gelling agent slurry and bentonite slurry obtained in step 1 and step 2 with the in-situ soil according to the mass fractions of 10% bentonite, 3% gelling agent and 87% in-situ soil.

[0055] The vertical anti-pollution barrier material can be used to block contaminated sites left behind by relocated chemical companies where the concentration of organic pollutants in groundwater is greater than or equal to 400 μg / L.

[0056] Example 4

[0057] This embodiment provides a vertical anti-fouling barrier material comprising bentonite, a gelling agent, and in-situ soil. The raw materials, by mass, are: 15% bentonite, 15% gelling agent, and 70% in-situ soil. The bentonite used in this embodiment is sodium-modified calcium-based bentonite. The gelling agent comprises activated red mud, granulated blast furnace slag powder, silica fume, and water glass, in a mass ratio of 68:24:12:4.

[0058] This embodiment also provides a method for preparing a vertical anti-fouling barrier material, comprising the following steps:

[0059] Step 1: mixing red mud with alkali metal hydroxide or carbonate, calcining the mixture at high temperature, cooling and sieving to obtain activated red mud, then mixing the activated red mud with water glass, pre-treated granulated blast furnace slag powder, and silica fume in proportion to obtain a gelling agent, and mixing the gelling agent with water to obtain a gelling agent slurry;

[0060] Specifically, Bayer process red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the resulting mixture is calcined and activated at a temperature of 700°C for 1 hour. The mixture is cooled and sieved to obtain activated red mud. The obtained activated red mud is uniformly mixed with granulated blast furnace slag powder, silica fume, and water glass in a proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill for 0.5 hour, dried at a temperature of 105°C, and screened with a sieve size of 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:4 and stirred at 1000 rpm for 20 minutes to obtain a gelling agent slurry.

[0061] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0062] Specifically, calcium-based bentonite and water were mixed in a mass ratio of 1:10, and then stirred at a speed of 1000 rpm for 20 minutes to obtain bentonite slurry.

[0063] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0064] Specifically, the vertical barrier material is obtained by mixing the gelling agent slurry and bentonite slurry obtained in step 1 and step 2 with the in-situ soil according to the mass fractions of 15% bentonite, 15% gelling agent and 70% in-situ soil.

[0065] The vertical anti-pollution barrier material can be used to block polluted sites of operating chemical enterprises where the concentration of organic pollutants in groundwater is greater than or equal to 400 μg / L.

[0066] Example 5

[0067] This embodiment provides a vertical anti-fouling barrier material comprising bentonite, a gelling agent, and in-situ soil. The raw materials, by mass, are: 10% bentonite, 3% gelling agent, and 87% in-situ soil. The bentonite used in this embodiment is sodium-modified calcium-based bentonite. The gelling agent comprises activated red mud, granulated blast furnace slag powder, silica fume, and water glass, in a mass ratio of 65:24:12:5.

[0068] This embodiment also provides a method for preparing a vertical anti-fouling barrier material, comprising the following steps:

[0069] Step 1: mixing red mud with alkali metal hydroxide or carbonate, calcining the mixture at high temperature, cooling and sieving to obtain activated red mud, then mixing the activated red mud with water glass, pre-treated granulated blast furnace slag powder, and silica fume in proportion to obtain a gelling agent, and mixing the gelling agent with water to obtain a gelling agent slurry;

[0070] Specifically, Bayer process red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the resulting mixture is calcined and activated at a temperature of 800°C for 2.5 hours. The mixture is cooled and sieved to obtain activated red mud. The activated red mud is uniformly mixed with granulated blast furnace slag powder, silica fume, and water glass in a proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill for 0.5 hours, dried at a temperature of 105°C, and screened with a sieve size of 200 mesh. The resulting gelling agent and water are mixed in a mass ratio of 1:5, and stirred at 1500 rpm for 15 minutes to obtain a gelling agent slurry.

[0071] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0072] Specifically, calcium-based bentonite and water were mixed in a mass ratio of 1:10, and then stirred at a speed of 1500 rpm for 15 minutes to obtain bentonite slurry.

[0073] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0074] Specifically, the vertical barrier material is obtained by mixing the gelling agent slurry and bentonite slurry obtained in step 1 and step 2 with the in-situ soil according to the mass fractions of 10% bentonite, 3% gelling agent and 87% in-situ soil.

[0075] The vertical anti-pollution barrier material can be used to block contaminated sites left behind by relocated chemical enterprises where the concentration of heavy metals in groundwater is greater than or equal to 20 mg / L and the concentration of organic pollutants is greater than or equal to 400 μg / L.

[0076] Example 6

[0077] This embodiment provides a vertical anti-fouling barrier material comprising bentonite, a gelling agent, and in-situ soil. The raw materials, by mass, are: 15% bentonite, 15% gelling agent, and 70% in-situ soil. The bentonite used in this embodiment is sodium-modified calcium-based bentonite. The gelling agent comprises activated red mud, granulated blast furnace slag powder, silica fume, and water glass, in a mass ratio of 60:25:15:5.

[0078] This embodiment also provides a method for preparing a vertical anti-fouling barrier material, comprising the following steps:

[0079] Step 1: mixing red mud with alkali metal hydroxide or carbonate, calcining the mixture at high temperature and then cold-sieving to obtain activated red mud, then mixing the activated red mud with water glass, pre-treated granulated blast furnace slag powder, and silica fume in proportion to obtain a gelling agent, and mixing the gelling agent with water to obtain a gelling agent slurry;

[0080] Specifically, Bayer process red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the resulting mixture is calcined and activated at a calcination temperature of 850°C for 2 hours, cooled and sieved to obtain activated red mud. The obtained activated red mud is uniformly mixed with granulated blast furnace slag powder, silica fume, and water glass in a proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill for 0.5 hours, dried at a drying temperature of 105°C, and screened with a sieve size of 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:3, and stirred at 2000 rpm for 10 minutes to obtain a gelling agent slurry.

[0081] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0082] Specifically, calcium-based bentonite and water were mixed in a mass ratio of 1:10, and then stirred at a speed of 2000 rpm for 10 minutes to obtain bentonite slurry.

[0083] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0084] Specifically, the vertical barrier material is obtained by mixing the gelling agent slurry and bentonite slurry obtained in step 1 and step 2 with the in-situ soil according to the mass fractions of 15% bentonite, 15% gelling agent and 70% in-situ soil.

[0085] The vertical anti-pollution barrier material can be used to block polluted sites of chemical enterprises in operation where the concentration of heavy metals in groundwater is greater than or equal to 20 mg / L and the concentration of organic pollutants is greater than or equal to 400 μg / L.

[0086] Comparative Example 1

[0087] The difference between this comparative example and Example 1 is that no gelling agent is added and the preparation method is modified accordingly. Specifically, the raw materials are as follows by mass: 15% sodium-modified calcium-based bentonite and 85% in-situ soil.

[0088] The method for preparing the vertical anti-fouling barrier material comprises the following steps:

[0089] (1) Bentonite and water were mixed in a mass ratio of 1:10 and stirred at 2500 rpm for 10 minutes to obtain bentonite slurry;

[0090] (2) The in-situ soil and bentonite slurry are fully mixed to obtain the vertical anti-fouling barrier material.

[0091] Comparative Example 2

[0092] This comparative example differs from Example 1 in the composition ratio of the vertical anti-fouling barrier material and the specific parameters used in the preparation method. Specifically, the composition is: 10% bentonite, 1% gelling agent, and 89% in-situ soil. The bentonite used in this comparative example is sodium-modified calcium-based bentonite. The gelling agent comprises activated red mud, granulated blast furnace slag powder, silica fume, and water glass in a mass ratio of 70:20:10:1.

[0093] The preparation method of the vertical anti-fouling barrier material comprises the following steps:

[0094] Step 1: mixing red mud with alkali metal hydroxide or carbonate, calcining the mixture at high temperature, cooling and sieving to obtain activated red mud, then mixing the activated red mud with water glass, pre-treated granulated blast furnace slag powder, and silica fume in proportion to obtain a gelling agent, and mixing the gelling agent with water to obtain a gelling agent slurry;

[0095] Specifically, Bayer process red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the resulting mixture is calcined and activated at a calcination temperature of 850°C for 2 hours, cooled and sieved to obtain activated red mud. The obtained activated red mud is uniformly mixed with granulated blast furnace slag powder, silica fume, and water glass in a proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill for 0.5 hours, dried at a drying temperature of 105°C, and screened with a sieve size of 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:3, and stirred at 2000 rpm for 10 minutes to obtain a gelling agent slurry.

[0096] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0097] Specifically, calcium-based bentonite and water were mixed in a mass ratio of 1:10, and then stirred at a speed of 2000 rpm for 10 minutes to obtain bentonite slurry.

[0098] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0099] Specifically, the vertical barrier material is obtained by mixing the gelling agent slurry and bentonite slurry obtained in step 1 and step 2 with the in-situ soil according to the mass fractions of 15% bentonite, 3% gelling agent and 87% in-situ soil.

[0100] Comparative Example 3

[0101] This comparative example differs from Example 1 in the composition ratio of the vertical anti-fouling barrier material and the specific parameters used in the preparation method. Specifically, the composition is 10% bentonite, 18% gelling agent, and 72% in-situ soil. The bentonite used in this comparative example is sodium-modified calcium-based bentonite. The gelling agent comprises activated red mud, granulated blast furnace slag powder, silica fume, and water glass in a mass ratio of 70:20:10:1.

[0102] The preparation method of the vertical anti-fouling barrier material comprises the following steps:

[0103] Step 1: mixing red mud with alkali metal hydroxide or carbonate, calcining the mixture at high temperature, cooling and sieving to obtain activated red mud, then mixing the activated red mud with water glass, pre-treated granulated blast furnace slag powder, and silica fume in proportion to obtain a gelling agent, and mixing the gelling agent with water to obtain a gelling agent slurry;

[0104] Specifically, Bayer process red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the resulting mixture is calcined and activated at a calcination temperature of 850°C for 2 hours, cooled and sieved to obtain activated red mud. The obtained activated red mud is uniformly mixed with granulated blast furnace slag powder, silica fume, and water glass in a proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill for 0.5 hours, dried at a drying temperature of 105°C, and screened with a sieve size of 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:3, and stirred at 2000 rpm for 10 minutes to obtain a gelling agent slurry.

[0105] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0106] Specifically, calcium-based bentonite and water were mixed in a mass ratio of 1:10, and then stirred at a speed of 2000 rpm for 10 minutes to obtain bentonite slurry.

[0107] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0108] Specifically, the vertical barrier material is obtained by mixing the gelling agent slurry and bentonite slurry obtained in step 1 and step 2 with the in-situ soil according to the mass fractions of 10% bentonite, 18% gelling agent and 72% in-situ soil.

[0109] Comparative Example 4

[0110] This comparative example differs from Example 1 in that the specific parameters used in the preparation method for the vertical anti-fouling barrier material are different: specifically, 10% bentonite, 3% gelling agent, and 87% in-situ soil. The bentonite used in this comparative example is sodium-modified calcium-based bentonite. The gelling agent comprises activated red mud, granulated blast furnace slag powder, silica fume, and water glass in a mass ratio of 70:20:10:1. The preparation process includes the following steps:

[0111] Step 1: mixing red mud with alkali metal hydroxide or carbonate, calcining the mixture at high temperature, cooling and sieving to obtain activated red mud, then mixing the activated red mud with water glass, pre-treated granulated blast furnace slag powder, and silica fume in proportion to obtain a gelling agent, and mixing the gelling agent with water to obtain a gelling agent slurry;

[0112] Specifically, Bayer process red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the resulting mixture is calcined and activated at a calcination temperature of 1000°C for 2 hours. The mixture is then cooled and sieved to obtain activated red mud. The activated red mud is then uniformly mixed with granulated blast furnace slag powder, silica fume, and water glass in a proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled for 0.5 hours, dried at 105°C, and sieved through a 200 mesh screen. The resulting gelling agent is then mixed with water in a mass ratio of 1:3 and stirred at 2000 rpm for 10 minutes to obtain a gelling agent slurry.

[0113] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0114] Specifically, calcium-based bentonite and water were mixed in a mass ratio of 1:10, and then stirred at a speed of 2000 rpm for 10 minutes to obtain bentonite slurry.

[0115] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0116] Specifically, the vertical barrier material is obtained by mixing the gelling agent slurry and bentonite slurry obtained in step 1 and step 2 with the in-situ soil according to the mass fractions of 10% bentonite, 3% gelling agent and 87% in-situ soil.

[0117] Comparative Example 5

[0118] The difference between this comparative example and Example 1 is that the specific parameters in the preparation method of the vertical anti-fouling barrier material are different. Specifically, the method includes the following steps:

[0119] Step 1: mixing red mud with alkali metal hydroxide or carbonate, calcining the mixture at high temperature, cooling and sieving to obtain activated red mud, then mixing the activated red mud with water glass, pre-treated granulated blast furnace slag powder, and silica fume in proportion to obtain a gelling agent, and mixing the gelling agent with water to obtain a gelling agent slurry;

[0120] Specifically, Bayer process red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the resulting mixture is calcined and activated at a calcination temperature of 400°C for 2 hours. The mixture is cooled and sieved to obtain activated red mud. The obtained activated red mud is uniformly mixed with granulated blast furnace slag powder, silica fume, and water glass in a proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill for 0.5 hours, dried at a drying temperature of 105°C, and screened with a sieve size of 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:3, and stirred at 2000 rpm for 10 minutes to obtain a gelling agent slurry.

[0121] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0122] Specifically, calcium-based bentonite and water were mixed in a mass ratio of 1:10, and then stirred at a speed of 2000 rpm for 10 minutes to obtain bentonite slurry.

[0123] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0124] Specifically, the vertical barrier material is obtained by mixing the gelling agent slurry and bentonite slurry obtained in step 1 and step 2 with the in-situ soil according to the mass fractions of 10% bentonite, 5% gelling agent and 85% in-situ soil.

[0125] Comparative Example 6

[0126] The difference between this comparative example and Example 1 is that the raw materials of the gelling agent in the vertical anti-fouling barrier material are different and the specific parameters in the preparation method are different. Specifically, the gelling agent is cement, and specifically, the cement is ordinary 42.5 grade cement.

[0127] The preparation method comprises the following steps:

[0128] Step 1: Mix cement and water to obtain a gelling agent slurry;

[0129] Specifically, cement and water were mixed in a mass ratio of 1:5, and stirred at a speed of 2000 rpm for 15 minutes to obtain a gelling agent slurry.

[0130] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0131] Specifically, calcium-based bentonite and water were mixed in a mass ratio of 1:10, and then stirred at a speed of 2000 rpm for 10 minutes to obtain bentonite slurry.

[0132] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0133] Specifically, the vertical barrier material is obtained by mixing the gelling agent slurry and bentonite slurry obtained in step 1 and step 2 with the in-situ soil according to the mass fractions of 10% bentonite, 3% gelling agent and 87% in-situ soil.

[0134] Comparative Example 7

[0135] The difference between this comparative example and Example 1 is that the ratio of the raw materials of the gelling agent in the vertical anti-fouling barrier material is different and the specific parameters in the preparation method are different. Specifically, the gelling agent includes activated red mud, granulated blast furnace slag powder, silica fume, and water glass, and the mass ratio is 55:25:20:5.

[0136] The preparation method comprises the following steps:

[0137] Step 1: mixing red mud with alkali metal hydroxide or carbonate, calcining the mixture at high temperature, cooling and sieving to obtain activated red mud, then mixing the activated red mud with water glass, pre-treated granulated blast furnace slag powder, and silica fume in proportion to obtain a gelling agent, and mixing the gelling agent with water to obtain a gelling agent slurry;

[0138] Specifically, Bayer process red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the resulting mixture is calcined and activated at a calcination temperature of 600°C for 1 hour, cooled and sieved to obtain activated red mud. The obtained activated red mud is uniformly mixed with granulated blast furnace slag powder, silica fume, and water glass in a proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill for 0.5 hour, dried at a drying temperature of 105°C, and screened with a sieve size of 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:5, and stirred at 2000 rpm for 10 minutes to obtain a gelling agent slurry.

[0139] Step 2: Mixing bentonite and water to obtain bentonite slurry;

[0140] Specifically, calcium-based bentonite and water were mixed in a mass ratio of 1:10, and then stirred at a speed of 2000 rpm for 10 minutes to obtain bentonite slurry.

[0141] Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

[0142] Specifically, the vertical barrier material is obtained by mixing the gelling agent slurry and bentonite slurry obtained in step 1 and step 2 with the in-situ soil according to the mass fractions of 10% bentonite, 3% gelling agent and 87% in-situ soil.

[0143] The above examples and comparative examples were subjected to three-day unconfined compressive strength tests and flexible wall permeability tests. The unconfined compressive strength test standard was based on the "Standard Test Method for Unconfined Compressive Strength of Cohesive Soil" (ASTM D2166-06) published by the American Society of Civil Engineers; the flexible wall permeability test standard was based on the "Standard Test Methods for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter" (ASTM D5084-10) published by the American Society of Civil Engineers. The test solution was lead nitrate (Pb(NO3)2) solution. The experimental results are shown in Table 1 below:

[0144] Table 1: Results of 3-day unconfined compressive strength test and flexible wall penetration test for Examples and Comparative Examples

[0145]

[0146] The test data in Table 1 show that the vertical anti-fouling barrier material formed according to the material composition ratio and preparation parameters of the present invention has an early strength greater than 170 kPa and a permeability coefficient lower than 1×10 m / s, meeting the use requirements of the vertical anti-fouling barrier.

[0147] The use of material composition ratios, gelling agent dosages, and preparation parameters that exceed those of the present invention will reduce the reactivity of the gelling agent, prevent the geopolymerization reaction from proceeding fully, and fail to form sufficient gelling products to fill the in-situ soil pores. Ultimately, the resulting vertical anti-fouling barrier material will have insufficient early strength and a permeability coefficient that cannot meet the service requirement of less than or equal to 1×10 m / s.

[0148] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be viewed as exemplary and non-restrictive in all respects. Furthermore, it should be understood that although this specification is described in terms of implementation methods, it does not encompass only one technical solution. This narrative is provided for clarity only, and those skilled in the art should consider the specification as a whole. The technical solutions in the embodiments may also be appropriately combined to form other implementation methods that are understandable to those skilled in the art.

Claims

1. A vertical anti-fouling barrier material, characterized in that: The invention comprises the following components in parts by weight: 10 to 15 parts of bentonite, 3 to 15 parts of a gelling agent and 70 to 87 parts of in-situ soil, wherein the gelling agent comprises activated red mud, blast furnace slag powder, silica fume and water glass; the mass ratio of the activated red mud, blast furnace slag powder, silica fume and water glass in the gelling agent is 60 to 70:20 to 25:10 to 15:1 to 5; the particle size of the gelling agent is less than or equal to 0.075 mm, and the specific surface area of ​​the gelling agent is greater than or equal to 400 m 2 / kg, the bentonite is calcium-based bentonite or modified calcium-based bentonite, and the red mud is Bayer process red mud.

2. A method for preparing a vertical anti-fouling barrier material as claimed in claim 1, characterized in that: The following steps are involved: Step 1: stirring and mixing red mud and an activator, calcining the mixture at high temperature, cooling and sieving to obtain activated red mud, then stirring and mixing the activated red mud with water glass, pre-treated granulated blast furnace slag powder, and pre-treated silica fume in proportion to obtain a gelling agent, and mixing the gelling agent with water to obtain a gelling agent slurry, wherein the pretreatment of the granulated blast furnace slag powder and silica fume includes ball milling, drying and sieving, the ball milling time is 0.5 to 1 hour, the drying temperature is 100 to 110° C., the sieve size is 200 mesh, the gelling agent and water are mixed in a mass ratio of 1:3 to 1:6, the stirring time is 10 to 20 minutes, and the stirring speed is 1000 to 3000 rpm; Step 2: Mixing bentonite and water to obtain bentonite slurry; Step 3: The in-situ soil, gelling agent slurry and bentonite slurry are fully mixed in proportion to obtain a vertical anti-fouling barrier material.

3. The method for preparing a vertical anti-fouling barrier material according to claim 2, characterized in that: In the step 1, the calcination temperature is 600-900° C., and the calcination time is 1-3 hours; and the activator is an alkali metal hydroxide or carbonate.

4. The method for preparing a vertical anti-fouling barrier material according to claim 3, characterized in that: In the step 2, bentonite and water are mixed in a mass ratio of 1:10, the stirring time is 10 to 20 minutes, and the stirring speed is 1000 to 3000 rpm.

5. Application of a vertical anti-pollution barrier material prepared according to claim 1 or claims 2-4 in risk management of contaminated sites, characterized in that: The vertical anti-pollution barrier material can be used to block contaminated sites where the concentration of heavy metals in groundwater is greater than or equal to 20 mg / L, or the concentration of organic pollutants is greater than or equal to 400 μg / L.

Images