Vertical antifouling barrier material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of vertical barrier materials, and particularly relates to a vertical antifouling barrier material and a preparation method and application thereof.The antifouling barrier material is prepared from, by mass, 10-15 parts of bentonite, 3-15 parts of gelling agent and 70-87 parts of in-situ soil, the gelling agent is prepared from activated red mud, blast furnace slag powder, silica fume and water glass, and the water glass is prepared from sodium silicate, sodium silicate and sodium silicate. By replacing cement with the gelling agent component, the adsorption capacity, the pollutant intercepting capacity and the early strength of the vertical antifouling barrier material are improved, a low-permeability antifouling barrier can be formed in a high-concentration organic pollution solution and a heavy metal pollution solution, pollutants are prevented from horizontally migrating along with underground water, and the pollution resistance of the vertical antifouling barrier material is improved. And thus, effective isolation management and control of the polluted site are realized. The vertical antifouling barrier material provided by the invention can be applied to a polluted site in which the underground water heavy metal concentration is greater than or equal to 20mg / L or the organic matter concentration is greater than or equal to 400mu g / 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 moved out of urban residential areas, leaving behind a large number of industrial pollution sites; at the same time, some chemical companies in production have also caused varying degrees of pollution around the sites due to insufficient management. The heavy metal and organic pollutants in these polluted sites can have strong mobility with the flow of groundwater, and isolation and control measures must be adopted to reduce the safety risks of pollutants to nearby residents and the surrounding environment.

[0003] Vertical barrier walls are widely used in risk prevention and control technologies for contaminated sites. Although they cannot directly eliminate the source of pollution, they can effectively control the migration of pollutants in contaminated sites, reduce and eliminate the negative impact 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 embedded geomembrane vertical barriers according to the type of materials. Vertical barriers containing bentonite, such as soil-cement-bentonite vertical isolation walls, are collectively referred to as bentonite-based vertical barrier barriers. They are widely used in anti-seepage and anti-pollution projects in contaminated sites due to their simple construction and low cost.

[0004] Bentonite is the main functional material of bentonite-based barrier. Its main mineral component, montmorillonite, undergoes strong volume expansion when it comes into contact with water, blocking the pores through which contaminated groundwater flows in the soil. Under the action of high concentrations of heavy metals, organic polluted liquids, and acid-base solutions, montmorillonite undergoes chemical erosion, and its expansion performance deteriorates significantly, resulting in the barrier being unable to meet the requirements of the permeability coefficient being less than 1×10 m / s 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, there is an urgent need to develop a vertical barrier material to overcome the shortcomings in practical applications. Summary of the invention

[0005] In view of the problem that the vertical barrier materials mentioned in the background technology have poor chemical compatibility in the prior art 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 a preparation method and method thereof. By adding activated red mud, blast furnace slag powder, silica fume and water glass instead of cement in 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, thereby blocking the horizontal migration of pollutants with groundwater, thereby achieving effective isolation and control of polluted 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 a better 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, and then mixing the activated red mud with water glass and 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: Mix bentonite and water to obtain bentonite slurry;

[0013] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 specification is 200 mesh.

[0016] Furthermore, in the step 1, the gelling agent and water are mixed at 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 polluted 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. The inventor of the present invention innovatively uses activated red mud, blast furnace slag powder, silica fume and water glass to replace traditional cement as gelling agent components, aiming at the problems of poor chemical compatibility of existing vertical barrier materials and easy erosion of bentonite minerals in high-concentration heavy metal and organic pollution solutions, resulting in failure of anti-pollution barriers. The strong adsorption capacity and low permeability of activated red mud, blast furnace slag powder and silica fume can be used to enhance the interception capacity of vertical anti-pollution barrier materials for pollutants, and form a double guarantee of interception with bentonite, ensuring that the vertical barrier material of the present invention can have a strong interception capacity in high-concentration heavy metal and organic pollution sites. At the same time, the particle size of the gelling agent is controlled by screening to ensure the reaction activity and reaction efficiency of the gelling agent.

[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 ineffective by high-concentration heavy metal and organic pollutant contaminated liquids; 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 extremely strong stability in high-concentration heavy metal and organic contaminated solutions, thereby ensuring that it meets the permeability requirements of the "Technical Specifications for Geotechnical Engineering of Sanitary Landfills for Domestic Waste" and the "Catalogue of Technologies for Remediation of Contaminated Sites (First Batch)" to be less than 1×10 -9 On the other hand, the combination of activated red mud, blast furnace slag powder, silica fume and water glass can form early strength and durability that is superior to cement, which can further enhance the application effect of vertical anti-pollution barrier materials in polluted sites that are controlled while being produced, strengthen the ability of vertical anti-pollution barriers to resist dry-wet cycles and freeze-thaw cycles, and improve the durability and service life of vertical anti-pollution barriers.

[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 picture 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, including bentonite, gelling agent and in-situ soil, wherein the raw materials are recorded by mass fraction as follows: 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 includes activated red mud, granulated blast furnace slag powder, silica fume and water glass, and the mass ratio is 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: stirring and mixing red mud and alkali metal hydroxide or carbonate, calcining the mixture at high temperature, cooling and sieving to obtain activated red mud, stirring and mixing the activated red mud with water glass and 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;

[0030] Specifically, the Bayer process red mud is uniformly mixed with alkali metal hydroxide or carbonate, wherein the alkali metal hydroxide is such as sodium hydroxide. The obtained mixture is calcined and activated, the calcination temperature is 600°C, the calcination time is 1h, and the activated red mud is obtained by cooling and sieving. The activated red mud obtained is uniformly mixed with granulated blast furnace slag powder, silica fume, and water glass in proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill and then dried and sieved. The ball milling time is 0.5h, the drying temperature is 105°C, and the sieve size is 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:5, and stirred at a speed of 1000 rpm for 15 minutes to obtain a gelling agent slurry.

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

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

[0033] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 one and step two 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 polluted 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, including bentonite, gelling agent and in-situ soil, wherein the raw materials are recorded by mass fraction as follows: 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 includes activated red mud, granulated blast furnace slag powder, silica fume and water glass, and the mass ratio is 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, and then mixing the activated red mud with water glass and 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 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, and then 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 proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill and then dried and sieved. The ball milling time is 0.5 hours, the drying temperature is 105°C, and the sieve size is 200 meshes. The obtained gelling agent and water are 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.

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

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

[0043] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 one and step two 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, including bentonite, gelling agent and in-situ soil, wherein the raw materials are recorded by mass fraction as follows: 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 includes activated red mud, granulated blast furnace slag powder, silica fume and water glass, and the mass ratio is 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, and then mixing the activated red mud with water glass and 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 red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the obtained mixture is calcined and activated at a calcination temperature of 700°C and a calcination time of 2.5 hours, and then 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 proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill and then dried and sieved. The ball milling time is 0.5 hours, the drying temperature is 105°C, and the sieve size is 200 meshes. The obtained gelling agent and water are mixed in a mass ratio of 1:4, and stirred at a speed of 2500 rpm for 15 minutes to obtain a gelling agent slurry.

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

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

[0053] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 one and step two 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 polluted 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, including bentonite, gelling agent and in-situ soil, wherein the raw materials are recorded by mass fraction as follows: 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 includes activated red mud, granulated blast furnace slag powder, silica fume and water glass, and the mass ratio is 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, and then mixing the activated red mud with water glass and 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 red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the obtained mixture is calcined and activated at a calcination temperature of 700°C and a calcination time of 1 hour, and then 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 proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill and then dried and sieved. The ball milling time is 0.5h, the drying temperature is 105°C, and the sieve size is 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:4, and stirred at a speed of 1000 rpm for 20 minutes to obtain a gelling agent slurry.

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

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

[0063] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 one and step two 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, including bentonite, gelling agent and in-situ soil, wherein the raw materials are recorded by mass fraction as follows: 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 includes activated red mud, granulated blast furnace slag powder, silica fume and water glass, and the mass ratio is 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, and then mixing the activated red mud with water glass and 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 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 2.5 hours, and then 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 proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill and then dried and sieved. The ball milling time is 0.5 hours, the drying temperature is 105°C, and the sieve size is 200 meshes. The obtained gelling agent and water are mixed in a mass ratio of 1:5, and stirred at a speed of 1500 rpm for 15 minutes to obtain a gelling agent slurry.

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

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

[0073] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 one and step two 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 polluted 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, including bentonite, gelling agent and in-situ soil, wherein the raw materials are recorded by mass fraction as follows: 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 includes activated red mud, granulated blast furnace slag powder, silica fume and water glass, and the mass ratio is 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 screening to obtain activated red mud, then mixing the activated red mud with water glass and 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 red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the obtained mixture is calcined and activated at a calcination temperature of 850°C and a calcination time of 2 hours, and then 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 proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill and then dried and sieved. The ball milling time is 0.5 hours, the drying temperature is 105°C, and the sieve size is 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:3, and stirred at a speed of 2000 rpm for 10 minutes to obtain a gelling agent slurry.

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

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

[0083] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 one and step two 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 operating chemical enterprises where the heavy metal concentration in groundwater is greater than or equal to 20 mg / L and the organic pollutant concentration 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 or used and no corresponding changes are made in the preparation method. Specifically, the raw materials are as follows by mass fraction: 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] The difference between this comparative example and Example 1 is that the proportion of the vertical anti-fouling barrier material components is different and the specific parameters in the preparation method are different, specifically: 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 includes activated red mud, granulated blast furnace slag powder, silica fume, and water glass, and the mass ratio is 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, and then mixing the activated red mud with water glass and 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 red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the obtained mixture is calcined and activated at a calcination temperature of 850°C and a calcination time of 2 hours, and then 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 proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill and then dried and sieved. The ball milling time is 0.5 hours, the drying temperature is 105°C, and the sieve size is 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:3, and stirred at a speed of 2000 rpm for 10 minutes to obtain a gelling agent slurry.

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

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

[0098] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 one and step two 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] The difference between this comparative example and Example 1 is that the vertical anti-fouling barrier material component ratio is different and the specific parameters in the preparation method are different, specifically: 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 includes activated red mud, granulated blast furnace slag powder, silica fume and water glass, and the mass ratio is 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, and then mixing the activated red mud with water glass and 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 red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the obtained mixture is calcined and activated at a calcination temperature of 850°C and a calcination time of 2 hours, and then 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 proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill and then dried and sieved. The ball milling time is 0.5 hours, the drying temperature is 105°C, and the sieve size is 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:3, and stirred at a speed of 2000 rpm for 10 minutes to obtain a gelling agent slurry.

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

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

[0107] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 one and step two 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] 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, 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 includes activated red mud, granulated blast furnace slag powder, silica fume, and water glass, and the mass ratio is 70:20:10:1. The following steps are included:

[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, and then mixing the activated red mud with water glass and 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 red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the obtained mixture is calcined and activated at a calcination temperature of 1000°C and a calcination time of 2 hours, and then 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 proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill and then dried and sieved. The ball milling time is 0.5h, the drying temperature is 105°C, and the sieve size is 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:3, and stirred at a speed of 2000 rpm for 10 minutes to obtain a gelling agent slurry.

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

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

[0115] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 one and step two 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 comprises 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, and then mixing the activated red mud with water glass and 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 red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the obtained mixture is calcined and activated at a calcination temperature of 400°C and a calcination time of 2 hours, and then 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 proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill and then dried and sieved. The ball milling time is 0.5 hours, the drying temperature is 105°C, and the sieve size is 200 meshes. The obtained gelling agent and water are mixed in a mass ratio of 1:3, and stirred at a speed of 2000 rpm for 10 minutes to obtain a gelling agent slurry.

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

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

[0123] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 one and step two 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 and stir 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: Mix bentonite and water to obtain bentonite slurry;

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

[0132] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 one and step two 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, and then mixing the activated red mud with water glass and 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 red mud is uniformly mixed with alkali metal hydroxide or carbonate, and the obtained mixture is calcined and activated at a calcination temperature of 600°C and a calcination time of 1 hour, and then 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 proportion to obtain a gelling agent. The granulated blast furnace slag powder and silica fume are first ball milled in a ball mill and then dried and sieved. The ball milling time is 0.5h, the drying temperature is 105°C, and the sieve size is 200 mesh. The obtained gelling agent and water are mixed in a mass ratio of 1:5, and stirred at a speed of 2000 rpm for 10 minutes to obtain a gelling agent slurry.

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

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

[0141] Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry 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 one and step two with the in-situ soil according to the mass fractions of 10% bentonite, 3% gelling agent and 87% in-situ soil.

[0143] The above-mentioned embodiments and comparative examples were subjected to 3-day unconfined compressive strength test and flexible wall permeability test, wherein the unconfined compressive strength test standard refers to 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 refers to 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, and the test solution is 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 of examples and comparative examples

[0145]

[0146] The test data in Table 1 show that the vertical antifouling 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, which meets the use requirements of the vertical antifouling barrier.

[0147] The use of material composition ratios, gelling agent dosages and preparation parameters beyond those of the present invention will reduce the reactivity of the gelling agent, and the geopolymerization reaction cannot be fully carried out, and sufficient gelling products cannot be formed to fill the in-situ soil pores, which ultimately manifests as insufficient early strength of the formed vertical anti-fouling barrier material and a permeability coefficient that cannot meet the service requirement of less than or equal to 1×10 m / s.

[0148] It is obvious 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 regarded as exemplary and non-restrictive from any point of view. In addition, it should be understood that although this specification is described in accordance with the implementation methods, it does not include only one technical solution. This narrative of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in the embodiments can also be appropriately combined to form other implementation methods that can be understood by 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 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.

2. A vertical anti-fouling barrier material according to claim 1, characterized in that: 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.

3. A vertical anti-fouling barrier material according to claim 2, characterized in that: 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.

4. A vertical anti-fouling barrier material according to claim 1, characterized in that: The bentonite is calcium-based bentonite or modified calcium-based bentonite, and the red mud is Bayer red mud.

5. A method for preparing a vertical antifouling barrier material as claimed in any one of claims 1 to 4, 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, stirring and mixing the activated red mud with water glass and 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; Step 2: Mix bentonite and water to obtain bentonite slurry; Step 3: Mix the in-situ soil, gelling agent slurry and bentonite slurry in proportion to obtain a vertical anti-fouling barrier material.

6. A method for preparing a vertical anti-fouling barrier material according to claim 5, 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.

7. A method for preparing a vertical anti-fouling barrier material according to claim 6, characterized in that: In the step 1, the pretreatment of the granulated blast furnace slag powder and silica fume includes ball milling, drying and screening. The ball milling time is 0.5 to 1 hour, the drying temperature is 100 to 110° C., and the sieve specification is 200 mesh.

8. A method for preparing a vertical anti-fouling barrier material according to claim 7, characterized in that: 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.

9. A method for preparing a vertical anti-fouling barrier material according to claim 5, characterized in that: 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.

10. Application of a vertical anti-fouling barrier material prepared according to claims 1-4 or claims 5-9 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.

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