Rapidly prototyped bentonite-based barrier and control material and method of manufacture

Abstract

The application discloses a kind of bentonite-based control materials of rapid prototyping and preparation method, including the following raw materials are made: bentonite, fly ash, blast furnace slag and excitation agent, wherein, the mass ratio of bentonite and fly ash is 1:0.2-0.4, based on the total mass of bentonite and fly ash, the addition amount of blast furnace slag is 10-20%, and the addition amount of excitation agent is 13.33-16.69%.After water glass and sodium hydroxide are dissolved in water, the excitation agent is prepared by adding modifier, the excitation agent is added to the dry powder sample mixed with fly ash and blast furnace slag, stirring, stuffing, adding bentonite and stirring into shape.The application uses water glass, phosphate and the like as excitation agent, uses industrial solid waste as supplementary admixture for required calcium, silicon, aluminum and other elements, the obtained control material has good compressive strength, good chemical compatibility, can realize rapid control function, and the penetration performance is two orders of magnitude lower than the national standard requirement after maintenance for 7d.

Description

Technical Field

[0001] This invention relates to a rapidly prototyping bentonite-based barrier material and its preparation method, belonging to the field of contaminated site barrier technology. Background Technology

[0002] In recent years, the chemical industry has developed rapidly. Whether it's accidental chemical explosions or leaks, or the numerous industrial sites left behind by industrial enterprises undergoing transformation and relocation, all cause serious pollution to the original soil and groundwater. Especially in major environmental emergencies requiring emergency response, if effective measures cannot be taken quickly to prevent the spread of pollution, these high-concentration pollutants will rapidly diffuse through the environmental media, causing even more severe impacts on the natural environment and the safety of people's lives and property. Therefore, developing a material that can be rapidly molded and effectively control pollutants is crucial.

[0003] Currently, the most widely used method in the field of contaminated site containment technology is cement-based containment materials. Traditional cement barrier walls are expensive to construct, have poor impermeability, and their overall performance is easily affected by high concentrations of pollutants, resulting in a significant decrease in their containment effect. Soil-bentonite barrier walls are more economical than cement-based barrier walls, but the walls are weak and prone to shrinkage cracks, which greatly reduces their containment effectiveness. HDPE geomembrane barrier walls have good impermeability, but they are difficult to construct, costly, and have a long construction period. Therefore, there is an urgent need to develop a barrier wall material that can achieve rapid containment, has high bentonite wall strength, low cost, and outstanding impermeability. Summary of the Invention

[0004] Objectives of the invention: The first objective of this invention is to provide a high-strength bentonite-based resistance control material that can be rapidly formed. The second objective of this invention is to provide a method for preparing the rapidly formed bentonite-based resistance control material.

[0005] Technical solution: The present invention discloses a rapidly prototyping bentonite-based resistance control material, comprising the following raw materials: bentonite, fly ash, blast furnace slag, and activator, wherein the mass ratio of bentonite to fly ash is 1:0.2-0.4, the amount of blast furnace slag added is 10-20% of the total mass of bentonite and fly ash, and the amount of activator added is 13.33-16.69% of the total mass of bentonite and fly ash.

[0006] Preferably, the mass ratio of bentonite to fly ash is 1:0.2.

[0007] Preferably, the amount of blast furnace slag added is 15% of the total mass of bentonite and fly ash.

[0008] Preferably, the amount of activator added is 14.21% of the total mass of bentonite and fly ash.

[0009] Preferably, the bentonite is calcium-based bentonite with a mesh size of 40-300.

[0010] Preferably, the fly ash is grade I steel slag or high-calcium fly ash, preferably fly ash #4, grade I steel slag or fly ash #1.

[0011] Preferably, the blast furnace slag is S105 grade slag powder.

[0012] Preferably, the activator solution is prepared by dissolving water glass and sodium hydroxide in deionized water and then adding a modifier.

[0013] More preferably, the modifier is a phosphate substance.

[0014] More preferably, the phosphate is one or more of dihydrogen phosphate, hexametaphosphate, tripolyphosphate, or pyrophosphate.

[0015] More preferably, the modulus of the water glass is 2.4.

[0016] More preferably, the mass ratio of water glass to sodium hydroxide is 16.8:0.473 to 2.365, more preferably 16.8:1.689, and the mass ratio of water glass to modifier is 16.8:1.4 to 4.2, more preferably 16.8:1.4.

[0017] A method for preparing a rapid prototyping bentonite-based resistance control material according to the present invention includes the following steps:

[0018] (1) Ball mill, sieve and dry bentonite, fly ash and blast furnace slag respectively;

[0019] (2) Mix the fly ash obtained in step (1) with blast furnace slag to obtain a dry powder sample;

[0020] (3) Water glass and sodium hydroxide are dissolved in deionized water, dissolved by ultrasonication in a water bath, a modifier is added and dissolved by ultrasonication in a water bath, stirred in a water bath, and aged to obtain an activator;

[0021] (4) Add the activator obtained in step (3) to the dry powder sample in step (2) and stir, then let it sit to obtain a slurry;

[0022] (5) Add the bentonite obtained in step (1) to the slurry obtained in step (4), stir quickly, pour into a mold to form, and let it cure naturally.

[0023] Preferably, in step (1), the ball milling time is 6-8 hours, the material is passed through a 40-200 mesh sieve, the drying temperature is 95-110℃, and the drying time is 24-36 hours.

[0024] Preferably, in step (2), the mixing time is more than 10 minutes.

[0025] Preferably, in step (3), the temperature of the water bath is 35-45℃, the time for ultrasonic dissolution in the water bath is 8-15 min, the time for continued ultrasonic dissolution in the water bath is 10-30 min, the time for stirring in the water bath is 8-15 min, and the time for aging is 20-50 min.

[0026] Preferably, in step (4), the stirring time is 5 to 10 minutes and the curing time is 2 to 10 minutes.

[0027] Preferably, in step (5), the rapid stirring time is 8 to 10 minutes.

[0028] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0029] (1) The main materials used in this invention are calcium-based bentonite, which has very abundant reserves in China, and fly ash, an industrial solid waste. Compared with traditional cement-based control materials, it is more green and low-carbon and realizes the rational utilization of solid waste resources. At the same time, the production cost is further reduced, achieving the advantages of cost reduction and efficiency improvement.

[0030] (2) The barrier material activator of the present invention performs joint activation modification on bentonite-fly ash #1-blast furnace slag mixture. In an alkaline environment, the glass in the mixture dissolves and Si-O-Si breaks, eventually forming hydration cementitious products such as CSH, CAH and CASH. These hydration cementitious products greatly improve the overall compressive strength of bentonite-based barrier materials, and also make the barrier materials more stable and more adaptable to the external environment of dry and wet cycles, thereby improving the universality of barrier control and solving the disadvantage of the weak soil-bentonite barrier wall.

[0031] (3) The activator of the barrier material in this invention needs to be mixed with blast furnace slag and fly ash first. The activator can be fully activated and dissolved by acting directly on the solid waste mixture (solid waste particles can be well activated and dissolved when the pH value is greater than 12). When calcium-based bentonite is added to the activator together with the solid waste mixture, the pH of the activator will decrease and part of the activator will combine with the calcium-based bentonite, thereby affecting the activation and dissolution of the solid waste mixture and reducing the overall performance of the material). After the curing is completed, calcium-based bentonite is added and mixed to finally form a high-performance bentonite-based barrier material.

[0032] (3) The present invention modifies the water glass and sodium hydroxide to form an activator by dissolving phosphate substances in the activator of the barrier material, thereby obtaining a modified activator with a better activating effect, which further improves the overall performance of the bentonite-based barrier material.

[0033] (4) This invention utilizes phosphate-based modifiers dissolved in the barrier material activator to increase the double electric layer thickness of bentonite particles, separate bentonite aggregates, and reduce pore size through ion exchange, chemical adsorption, and steric stabilization. This results in improved calcium-based bentonite with higher expansibility, better dispersibility, and impermeability. It further enhances the expansion performance of bentonite (modification and alkali activation must be carried out simultaneously; otherwise, a dense internal structure cannot be formed). Simultaneously, the bentonite structure fills the pores of the hydrated gel material after water absorption. During the expansion process, the modified bentonite fully fills each pore, and under the dual effects of the hydration gel skeleton binding and bentonite expansion, the interior of the barrier material gradually becomes denser. Therefore, the impermeability of the barrier material is greatly improved, exceeding the national standard value of 1 x 10. -11 The speed decreased by two orders of magnitude.

[0034] (5) The high-strength bentonite-based barrier material provided by the present invention has good chemical compatibility, acid and alkali resistance, and high salt resistance.

[0035] (6) The preparation method of the high-strength bentonite-based barrier material that can be rapidly controlled by the present invention is simple and widely applicable. It can be used as a vertical barrier material and as a horizontal barrier material.

[0036] (7) This invention uses water glass, phosphate, etc. as activators and modifiers, and industrial solid waste as a supplementary admixture to obtain the required calcium, silicon, aluminum, and other elements. The resulting barrier material has good compressive strength, good chemical compatibility, and can achieve rapid barrier function. After 7 days of curing, the permeability reaches 0.97 x 10. -9 The compressive strength is 0.93 MPa after 24 hours of curing, 2.5 MPa after 3 days of curing, and 8.8 MPa after 28 days. It is two orders of magnitude lower than the national standard requirement. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating the overall process of a rapid prototyping method for preparing bentonite-based resistance control materials according to the present invention. Detailed Implementation

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0039] The fly ash #1 used in the following experiments was purchased from Guyue Mineral Products Co., Ltd., and the other fly ash was purchased from Hebei Zongrun Mineral Products Co., Ltd. The types, components and contents of all fly ash are shown in Table 1 below.

[0040] The blast furnace slag is S105 grade slag powder, purchased from Lingshou County Dehang Mineral Products Co., Ltd., and the component content is shown in Table 1 below;

[0041] The calcium-based bentonite was purchased from Zhenjiang Mufeng Bentonite Company, with a particle size of 40-200 mesh.

[0042] The steel slag was purchased from Gongyi Yuanheng Water Purification Materials Factory.

[0043] 2.4 The water glass was purchased from Tianjin Huasheng Chemical Reagent Co., Ltd.

[0044] Analytical grade sodium hexametaphosphate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0045] Analytical grade sodium hydroxide was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0046] Table 1. Types of fly ash, content of components, and content of each component (%)

[0047]

[0048] Note: Fly ash #1 is gray-green high-calcium fly ash, fly ash #2 is gray low-calcium fly ash, fly ash #3 is black low-calcium fly ash, and fly ash #4 is white high-calcium fly ash.

[0049] Example 1

[0050] 1. According to the mass percentage of calcium-based bentonite to fly ash #1 of 1:0.2, take 116.67g of calcium-based bentonite and 23.33g of fly ash #1, totaling 140g. The amount of blast furnace slag added is 15% of the total amount of calcium-based bentonite and fly ash #1 (140g). The amount of 2.4mold water glass used is 12% of the total amount of calcium-based bentonite and fly ash #1 (140g). The amount of analytical grade sodium hydroxide used is 1.206% of the total amount of calcium-based bentonite and fly ash #1 (140g). The amount of sodium hexametaphosphate used is 1% of the total amount of calcium-based bentonite and fly ash #1 (140g).

[0051] In this process, calcium-based bentonite, fly ash #1, and blast furnace slag were first dried at 105℃, then ground using a planetary ball mill for 6 hours. The ground samples were then sieved through a 200-mesh sieve. The coarse particles that did not pass through the sieve were subjected to a second high-speed grinding and sieving. The collected 200-mesh samples were dried again at 105℃ for 24 hours to obtain powder samples of calcium-based bentonite, fly ash #1, and blast furnace slag.

[0052] Accurately weighed GGBS and fly ash #1 powder were uniformly mixed in a stirrer for 10 minutes to obtain a dry powder sample. A measured amount of 2.4-mold water glass was added to 70 mL of ultrapure water for dissolution. Simultaneously, accurately weighed analytical grade sodium hydroxide was added. The mixture was ultrasonically dispersed in a 40°C water bath with appropriate stirring aided by a glass rod until completely dissolved. Then, accurately weighed analytical grade sodium hexametaphosphate was added. The dissolution of sodium hydroxide and sodium hexametaphosphate releases a large amount of heat, promoting the interaction between sodium hydroxide, sodium hexametaphosphate, and 2.4-mold water glass. The mixture was then ultrasonically broken down and dissolved at 40°C for 10 minutes, followed by another 10 minutes of ultrasonic dispersion and dissolution in a water bath with a glass rod. Stirring with a glass rod until completely dissolved, then magnetically stirred at 40℃ (800 r / min) for 5 minutes. After dissolution, age at room temperature for 30 minutes. Finally, pour the stirred resistance material activation solution into a stirrer and mix with the dry powder sample. Stir for 10 minutes, then add the weighed calcium-based bentonite to the slurry and continue stirring for 10 minutes. After mixing evenly, let it sit for 8 minutes. Finally, pour it into a circular mold (50 mm inner diameter, 50 mm height) and cure to obtain the bentonite-based resistance material. Naturally cure for 24 h and 72 h. The preparation process is as follows. Figure 1 As shown.

[0053] 2. Take calcium-based bentonite and fly ash #1 at mass percentages of 1:0, 1:0.4, 1:0.6, and 1:1 respectively, keeping the mass of other components the same as in step 1. Repeat the experimental process of step 1 to obtain 4 groups of bentonite-based resistance control materials, and allow them to cure naturally for 24h and 72h respectively.

[0054] Unconfined compressive strength tests were conducted on the bentonite-based resistance materials that had undergone natural curing for 24 hours and 72 hours, as obtained from the aforementioned five sets of experiments. The performance test results are shown in Table 2. (Unconfined compressive strength = pressure / area under stress)

[0055] Table 2. Unconfined compressive strength of bentonite-based resistance materials prepared with different mass percentages of calcium-based bentonite and fly ash.

[0056] Proportion 1：0 1：0.2 1：0.4 1：0.6 1：1 1-day unconfined compressive strength (Pa) 715820.3 930439.2 754273.9 651193.7 626809.3 3-day unconfined compressive strength (Pa) 1386233 2496075.5 1972445.5 1701261.3 1408967

[0057] As shown in Table 2, with the increase of the mass percentage of calcium-based bentonite to fly ash #1, the unconfined compressive strength showed a trend of first increasing and then decreasing. When the mass percentage of calcium-based bentonite to fly ash #1 was in the range of 1:0-0.4, the 1-day unconfined compressive strength was better, and the 1-day unconfined compressive strength exceeded 0.73 MPa. Especially when the ratio was 1:0.2, the 1-day unconfined compressive strength reached as high as 0.93 MPa. However, at 3 days, The unconfined compressive strength of calcium-based bentonite with a mass percentage of 1:0 (i.e., without fly ash #1) is significantly lower. However, the unconfined compressive strength of calcium-based bentonite with a mass percentage of 1:0.2-0.4 (with fly ash #1) is still better. This shows that a mass percentage of 1:0.2-0.4 (with fly ash #1) is more suitable, with 1:0.2 being the optimal value. Its 1-day and 3-day unconfined compressive strengths are far superior to other groups.

[0058] Example 2

[0059] The experimental procedure was the same as in Example 1, except that the mass ratio of calcium-based bentonite to fly ash was 1:0.2, totaling 140g. The amount of blast furnace slag added was 15% of the total 140g of calcium-based bentonite and fly ash, the amount of 2,4-mold water glass was 12% of the total 140g of calcium-based bentonite and fly ash, the amount of analytical grade sodium hydroxide was 1.206% of the total 140g of calcium-based bentonite and fly ash, and the amount of sodium hexametaphosphate was 1% of the total 140g of calcium-based bentonite and fly ash. The fly ash used was fly ash #2, fly ash #3, fly ash #4, grade I steel slag, and grade II steel slag, compared with the same amount of fly ash #1 in Example 1. Bentonite-based resistance control materials were prepared and naturally cured for 72h. The unconfined compressive strength test was the same as in Example 1, and the results are shown in Table 3.

[0060] Table 3 Unconfined compressive strength of bentonite-based resistance materials prepared from different fly ash samples

[0061]

[0062]

[0063] As shown in Table 3, only fly ash #4, grade I steel slag, grade II steel slag, and fly ash #1 used in Example 1 have an unconfined compressive strength higher than 0.71 MPa in 1 day. The unconfined compressive strength of the other two types is significantly lower. By 3 days, the unconfined compressive strength of grade II steel slag is much lower than that of fly ash #4, grade I steel slag, and fly ash #1 used in Example 1. It is evident that fly ash #4, grade I steel slag, and fly ash #1 are better choices, especially fly ash #1 used in Example 1, whose unconfined compressive strength in 1-3 days exceeds that of the other groups.

[0064] Example 3

[0065] The experimental procedure is the same as in Example 1, except that the mass ratio of calcium-based bentonite to fly ash #1 is 1:0.2, totaling 140g. The amount of blast furnace slag added is 15% of the total 140g of calcium-based bentonite and fly ash #1, the amount of 2,4-mold water glass used is 12% of the total 140g of calcium-based bentonite and fly ash #1, the amount of analytical grade sodium hydroxide used is 1.206% of the total 140g of calcium-based bentonite and fly ash #1, and the amount of sodium hexametaphosphate used is 1% of the total 140g of calcium-based bentonite and fly ash #1. The difference lies in the timing of the addition of sodium hexametaphosphate during the preparation process, as detailed below:

[0066] Accurately weighed GGBS and fly ash #1 powder were uniformly mixed in a mixer for 10 minutes to obtain a dry powder sample. Then, accurately weighed sodium hexametaphosphate and calcium-based bentonite powder were mixed in dry powder to obtain a mixed sample. A measured amount of 2.4-mold water glass was dissolved in 70 mL of ultrapure water, along with accurately weighed analytical grade sodium hydroxide. The solution was ultrasonically dispersed in a 40°C solution with appropriate stirring using a glass rod until completely dissolved. The dissolution of sodium hydroxide released a large amount of heat, promoting the interaction between the sodium hydroxide and the 2.4-mold water glass. The solution was then ultrasonically broken down and dissolved at 40°C for 10 minutes with stirring using a glass rod until completely dissolved. Following this, magnetic stirring at 40°C (800 rpm) was performed for 5 minutes. After complete dissolution, the solution was aged at room temperature for 30 minutes. Finally, the stirred resistance material activation solution was poured into a stirrer and mixed with the dry powder sample. After stirring for 10 minutes, a measured amount of calcium-based bentonite was added to the slurry, and stirring was continued for another 10 minutes. After thorough mixing, the mixture was left to stand for 8 minutes. Finally, it was poured into a circular mold (50 mm inner diameter, 50 mm height) and cured to obtain the bentonite-based resistance material. Natural curing was performed for 24 h and 72 h. The unconfined compressive strength test was the same as in Example 1, and the results are shown in Table 4.

[0067] Example 4

[0068] The experimental procedure is the same as in Example 1, except that the mass ratio of calcium-based bentonite to fly ash #1 is 1:0.2, totaling 140g. The amount of blast furnace slag added is 15% of the total 140g of calcium-based bentonite and fly ash #1, the amount of 2,4-mold water glass used is 12% of the total 140g of calcium-based bentonite and fly ash #1, the amount of analytical grade sodium hydroxide used is 1.206% of the total 140g of calcium-based bentonite and fly ash #1, and the amount of sodium hexametaphosphate used is 1% of the total 140g of calcium-based bentonite and fly ash #1. The difference lies in the timing of the addition of calcium-based bentonite during the preparation process, as detailed below:

[0069] Accurately weighed hot GGBS, hot fly ash #1, and calcium-based bentonite powder were mixed evenly in a mixer for 10 minutes to obtain a dry powder sample. A measured amount of 2.4-mold water glass was dissolved in 70 mL of ultrapure water, along with accurately weighed analytical grade sodium hydroxide. The solution was ultrasonically dispersed in a 40°C water bath and stirred with a glass rod until completely dissolved. Then, accurately weighed analytical grade sodium hexametaphosphate was added. The dissolution of sodium hydroxide and sodium hexametaphosphate released a large amount of heat, promoting the interaction between sodium hydroxide, sodium hexametaphosphate, and 2.4-mold water glass. The solution was then ultrasonically broken down and dissolved at 40°C for 10 minutes, followed by ultrasonic dispersion and dissolution in a water bath for 10 minutes, with stirring with a glass rod until completely dissolved. Then, it was magnetically stirred at 40°C (800 rpm) for 5 minutes. After dissolution, it was aged at room temperature for 30 minutes. Finally, the stirred resistance material activation solution was poured into a stirrer and mixed with the dry powder sample. After stirring for 10 minutes, the mixture was left to stand for 8 minutes. Finally, it was poured into a circular mold (50 mm inner diameter, 50 mm height) and cured to obtain the bentonite-based resistance material. The material was then naturally cured for 24 h and 72 h. The 1-day and 3-day unconfined compressive strength tests were the same as in Example 1, and the results are shown in Table 4.

[0070] Table 4 Unconfined compressive strength of sodium hexametaphosphate or calcium-based bentonite added at different times

[0071] Preparation method Example 1 Example 3 Example 4 1-day unconfined compressive strength (Pa) 930439.2 788899.2 711995.6 3-day unconfined compressive strength (Pa) 2496075.5 2047142.9 1916693.1

[0072] As shown in Table 4, although the unconfined compressive strength of the bentonite-based resistance materials prepared by adding sodium hexametaphosphate or calcium-based bentonite at different times was greater than 0.71 MPa, the unconfined compressive strength increased by 0.14 MPa when sodium hexametaphosphate was added to the activation solution of the resistance material compared to when it was added directly to calcium-based bentonite. However, when calcium-based bentonite was directly mixed with GGBS and fly ash #1, even with the addition of sodium hexametaphosphate to the activation solution of the resistance material, the unconfined compressive strength of the prepared bentonite-based resistance material decreased significantly by more than 0.22 MPa. This indicates that the addition time of sodium hexametaphosphate and calcium-based bentonite has a significant impact on the performance of the prepared bentonite-based resistance materials. Acid-base tests on the materials revealed the following pH values: Example 1: 12.39; Example 3: 11.34; Example 4: 10.93.

[0073] Example 5

[0074] The experimental procedure was the same as in Example 1, except that the mass ratio of calcium-based bentonite to fly ash #1 was 1:0.2, totaling 140g. The addition amounts of blast furnace slag were 0%, 5%, 10%, 20%, and 25% of the total 140g of calcium-based bentonite and fly ash #1, respectively. The amount of 2,4-mold water glass was 12% of the total 140g of calcium-based bentonite and fly ash #1. The amount of analytical grade sodium hydroxide was 1.206% of the total 140g of calcium-based bentonite and fly ash #1, and the amount of sodium hexametaphosphate was 1% of the total 140g of calcium-based bentonite and fly ash #1. The unconfined compressive strength test was the same as in Example 1, and the results are shown in Table 5.

[0075] Table 5 Unconfined compressive strength measured at different times under different GGBS addition amounts

[0076]

[0077]

[0078] As shown in Table 5, within 1-3 days, the unconfined compressive strength of the prepared bentonite-based resistance control material first increased and then decreased with the increase of GGBS addition. When the GGBS addition was 10-20%, the 1-day unconfined compressive strength of the prepared bentonite-based resistance control material exceeded 0.74 MPa. After 3 days, when the GGBS addition was 10-20%, the unconfined compressive strength of the prepared bentonite-based resistance control material exceeded 1.78 MPa, which was higher than other addition amounts. This indicates that the GGBS addition was best controlled at 10-25%, with 15% showing the best effect.

[0079] Example 6

[0080] The experimental procedure was the same as in Example 1, except that the mass ratio of calcium-based bentonite to fly ash #1 was 1:0.2, totaling 140g. The amount of blast furnace slag added was 15% of the total 140g of calcium-based bentonite and fly ash #1, the amount of 2,4-mold water glass was 12% of the total 140g of calcium-based bentonite and fly ash #1, the amount of analytical grade sodium hydroxide was 1.206% of the total 140g of calcium-based bentonite and fly ash #1, and the amount of sodium hexametaphosphate was 0%, 1%, 2%, 3%, 4%, and 5% of the total 140g of calcium-based bentonite and fly ash #1. The unconfined compressive strength test was the same as in Example 1, and the results are shown in Table 6.

[0081] Table 6. Unconfined compressive strength measured at different times under different sodium hexametaphosphate additions.

[0082]

[0083] As shown in Table 6, within 1-3 days, the unconfined compressive strength of the prepared bentonite-based resistance materials first increased and then decreased with the increase of sodium hexametaphosphate (GGBS) addition. Furthermore, within 1 day, when the GGBS addition was 1-3%, the unconfined compressive strength of the prepared bentonite-based resistance materials exceeded 0.79 MPa. After 3 days, when the GGBS addition was 1-3%, the unconfined compressive strength of the prepared bentonite-based resistance materials exceeded 2 MPa, higher than other addition amounts. This indicates that controlling the GGBS addition to 1-3% is more appropriate, with 1% showing the best effect.

[0084] Example 7

[0085] The experimental procedure was the same as in Example 1, except that the mass ratio of calcium-based bentonite to fly ash #1 was 1:0.2, totaling 140g. The amount of blast furnace slag added was 15% of the total 140g of calcium-based bentonite and fly ash #1. The amount of 2,4-mold water glass used was 12% of the total 140g of calcium-based bentonite and fly ash #1. The amounts of sodium hexametaphosphate used were 0%, 1%, 2%, 3%, 4%, and 5% of the total 140g of calcium-based bentonite and fly ash #1. The unconfined compressive strength test was the same as in Example 1, and the results are shown in Table 6. To more accurately determine the optimal dosage of sodium hydroxide, the dosage was calculated based on the SiO2 / Na2O ratio. The calculated dosages of analytical grade sodium hydroxide were set to 0 g, 0.215 g, 0.473 g, 0.788 g, 1.182 g, 1.689 g, 2.365 g, and 3.311 g, respectively. This corresponds to 0%, 0.154%, 0.338%, 0.563%, 0.844%, 1.206%, 1.689%, and 2.365% of the total amount of calcium-based bentonite and fly ash #1 (140 g). The results are shown in Table 7.

[0086] Table 7. Effect of activators with different SiO2 / Na2O ratios on unconfined compressive strength of resistive materials.

[0087]

[0088] As shown in Table 7, within 1-3 days, the unconfined compressive strength of the prepared bentonite-based resistance materials first increased and then decreased with increasing SiO2 / Na2O mass ratio. Within one day, when the SiO2 / Na2O mass ratio was 1.2-2.0, the unconfined compressive strength of the prepared bentonite-based resistance materials exceeded 0.84 MPa. After 3 days, when the SiO2 / Na2O mass ratio was 1.2-2.0, the unconfined compressive strength of the prepared bentonite-based resistance materials exceeded 2 MPa, higher than other addition amounts. This indicates that controlling the SiO2 / Na2O mass ratio at 1.2-2.0 is more suitable, with the best effect at a mass ratio of 1.4, at which point the sodium hydroxide addition amount is 1.689 g.

[0089] Example 8

[0090] The experimental procedure is the same as in Example 1, except that the molding die is replaced with a ring cutter with an edge. The test—a variable head permeability test—is conducted according to the test methods in industry standard JTG 3430-2020 "Specifications for Geotechnical Testing of Highways". The inner diameter of the ring cutter is 61.8 mm, and the height is 40 mm. The permeability coefficient of the permeable stone should be greater than 1×10⁻³ cm / s. The formula for calculating the variable head permeability coefficient is:

[0091]

[0092] In the formula k t denoted as t℃, where t is the permeability coefficient of the sample (cm / s), and a is the inner diameter and area of ​​the variable head pipe (cm²). 2 L is the sample height, H1 is the starting head, H2 is the ending head, and A is the cross-sectional area of ​​the water passage (cm²). 2 The results are shown in Table 8.

[0093] Table 8. Permeability of bentonite-based barrier materials under different curing times (National Standard: 1×10⁻⁶) -7 cm / s)

[0094]

[0095] As shown in Table 8, this embodiment tested the permeability of bentonite-based barrier materials under different curing times. Specifically, the initial permeability coefficient (after 6 hours of curing) of the bentonite-based barrier material reached 4.47 × 10⁻⁶ after 12 hours of curing. -8 The permeability was cm / s, which is an order of magnitude lower than the national standard requirement. However, after 7 days of curing, the permeability parameter reached 6.76 × 10⁻⁶ cm / s. -9 The permeability is reduced by two orders of magnitude compared to the national standard requirement, and even after 7 days of infiltration, the permeability parameter can still reach 1.1 × 10⁻⁶ cm / s. -9 The permeability coefficient is reduced by two orders of magnitude compared to the national standard requirement, making this material suitable for some sudden emergency containment scenarios. Furthermore, it can be seen that the permeability coefficient decreases further with increasing curing time, reaching a minimum of 0.97 × 10⁻⁶ after 28 days of infiltration. -9 The flow rate is cm / s, which is two orders of magnitude lower than the national standard, indicating that the bentonite-based barrier material has excellent seepage prevention performance.

Claims

1. A quick-forming bentonite-based barrier and control material, characterized in that, The bentonite-based control material is prepared by the following steps: The bentonite-based control material is prepared by the following steps: (1) ball milling, sieving and drying bentonite, fly ash and blast furnace slag respectively; (2) mixing the fly ash and blast furnace slag obtained in step (1) to obtain a dry powder sample; (3) dissolving water glass and sodium hydroxide in deionized water, ultrasonic dissolving in a water bath, continuing ultrasonic dissolving in a water bath after adding a modifier, water bath stirring, aging to obtain an activator; (4) adding the activator obtained in step (3) to the dry powder sample in step (2) and stirring, then steaming to obtain a slurry; (5) adding the bentonite obtained in step (1) to the slurry obtained in step (4), quickly stirring, pouring into a mold and naturally curing.

2. The rapid prototyped bentonite-based barrier and control material of claim 1, wherein, The bentonite is calcium-based bentonite with a mesh size of 40-300.

3. The rapid prototyped bentonite-based barrier and control material of claim 1, wherein, The blast furnace slag is S105 grade slag powder.

4. The rapid prototyped bentonite-based barrier and control material of claim 1, wherein, The phosphate substance is one or more of dihydrogen phosphate, hexametaphosphate, tripolyphosphate or pyrophosphate.

5. A method of preparing the quick-forming bentonite-based barrier and control material according to any one of claims 1 to 4, characterized in that, The bentonite-based control material is prepared by the following steps: (1) ball milling, sieving and drying bentonite, fly ash and blast furnace slag respectively; (2) mixing the fly ash and blast furnace slag obtained in step (1) to obtain a dry powder sample; (3) dissolving water glass and sodium hydroxide in deionized water, ultrasonic dissolving in a water bath, continuing ultrasonic dissolving in a water bath after adding a modifier, water bath stirring, aging to obtain an activator; (4) adding the activator obtained in step (3) to the dry powder sample in step (2) and stirring, then steaming to obtain a slurry; (5) adding the bentonite obtained in step (1) to the slurry obtained in step (4), quickly stirring, pouring into a mold and naturally curing.

6. The preparation method according to claim 5, characterized in that, In step (1), the ball milling time is 6-8 h, the sieving is performed through a mesh of 40-200, the drying temperature is 95-110 ℃, and the drying time is 24-36 h; in step (2), the mixing time is more than 10 min.

7. The preparation method according to claim 5, characterized in that, In step (3), the water bath temperature is 35-45 ℃, the ultrasonic dissolving time in a water bath is 8-15 min, the continuing ultrasonic dissolving time in a water bath is 10-30 min, the water bath stirring time is 8-15 min, and the aging time is 20-50 min; in step (4), the stirring time is 5-10 min, and the steaming time is 2-10 min; in step (5), the quick stirring time is 8-10 min.

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