Curing agent for enhancing mechanical properties of land, and preparation method and application thereof

Abstract

The invention particularly relates to a curing agent for enhancing mechanical properties of land, a preparation method and application thereof, and the curing agent is prepared from the following components in parts by mass: 10-15 parts of red mud, 30-40 parts of slag and 3-6 parts of modified nylon fiber. The preparation method of the modified nylon fiber comprises the following steps: S101, treating the nylon fiber through a metal salt solution; s102, nylon fibers are treated through alkali liquor; s103, combining graphene on the outer side of the nylon fiber; s104, nylon fibers are combined with graphene and impregnated with epoxy resin. According to the prepared soil stabilizer, solid waste is effectively utilized, and the prepared stabilizer can effectively improve the mechanical strength of solidified soil.

Description

Technical Field

[0001] The present invention relates to the technical field of soil solidification, and specifically to a solidifying agent for enhancing the mechanical properties of land, a preparation method thereof, and an application thereof. Background Technique

[0002] Past industrial development has neglected the harm to the environment, resulting in serious soil pollution problems, especially heavy metal soil pollution. Heavy metal pollution can endanger human health and the ecological environment through migration with groundwater. Moreover, the adverse impact of heavy metals on the mechanical strength of soil poses a huge challenge to the reconstruction of polluted sites. The solidification / stabilization technology is a proven and efficient method for treating polluted soil, which is easy to implement and has a relatively low cost. It can not only reduce the leaching concentration of heavy metals but also enhance the soil strength. In the past, cement and lime were usually used as solidifying agents. However, the widespread use of traditional solidifying agents such as cement or lime has increased production costs and carbon emissions, highlighting the importance of finding economic and environmentally friendly alternatives.

[0003] Red mud is an industrial solid waste discharged during the extraction of alumina in the aluminum industry. Due to its high alkalinity and particle size characteristics, it has great potential in repairing polluted soil. A large amount of red mud is piled up in the open air, which not only occupies land but also pollutes the soil and groundwater. Ground granulated blast-furnace slag is a by-product of the steel smelting process and has high hydration and cementation properties in an alkali-activated state, and can be used as a substitute for lime as a solidifying agent for polluted soil. Adding the above two materials to polluted soil can not only improve the compressive strength of the soil but also reduce the leaching rate of heavy metals in the soil. Many studies have confirmed the efficient role of this composite cementitious material system in soil remediation and road engineering.

[0004] In view of the problems raised in the above background technique, those skilled in the art propose a soil solidifying agent based on slag and red mud, and adding modified nylon fibers to enhance the solidification effect on lead-polluted soil. Summary of the Invention

[0005] The purpose of the present invention is to provide a solidifying agent for enhancing the mechanical properties of land, a preparation method thereof, and an application thereof, so as to solve the problems raised in the above background technique.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A solidifying agent for enhancing the mechanical properties of land includes the following components by mass: 10-15 parts of red mud, 30-40 parts of slag, and 3-6 parts of modified nylon fiber;

[0008] The preparation method of the modified nylon fiber includes the following steps:

[0009] S101. Put nylon fibers into a mixed solution of calcium chloride with a concentration of 2 - 4 mol / L and copper chloride with a concentration of 0.5 - 2 mol / L, heat to 40 - 60 °C and soak for 0.5 - 2 h. Then take out the nylon fibers and wash them with sufficient deionized water. The washed nylon fibers are vacuum-dried once at 20 - 40 °C for 2 - 5 h;

[0010] S102. Put the nylon fibers vacuum-dried once in step S101 into a sodium hydroxide solution with a concentration of 1 - 4 mol / L and soak for 0.5 - 1 h. After soaking, wash with sufficient deionized water and vacuum-dry twice at 40 - 80 °C for 1 - 2 h;

[0011] S103. Place the nylon fibers vacuum-dried twice in step S102 in the graphene dispersion and stir magnetically for 1 - 3 h. Then evaporate and dry the graphite dispersion at 50 - 80 °C until the deionized water is completely evaporated to obtain pretreated nylon fibers. The graphene dispersion also includes polyvinylpyrrolidone, sodium carboxymethyl cellulose, and sodium dodecylbenzenesulfonate;

[0012] S104. Put the pretreated nylon fibers obtained in step S103 into epoxy resin for impregnation, and obtain modified nylon fibers after curing.

[0013] Further, the mass ratio of the nylon fibers to the mixed solution of calcium chloride and copper chloride in step S101 is 1:(30 - 50).

[0014] Further, the mass ratio of the nylon fibers vacuum-dried once in step S101 to the sodium hydroxide solution in step S102 is 1:(20 - 50).

[0015] Further, the mass ratio of sodium dodecylbenzenesulfonate, graphene, polyvinylpyrrolidone, sodium carboxymethyl cellulose, deionized water in the graphene dispersion to the nylon fibers vacuum-dried twice in step S102 added to the graphene dispersion is 1:(25 - 50):(10 - 50):(10 - 100):(1000 - 2000):(100 - 500).

[0016] Further, the epoxy resin in step S104 contains a curing agent and inorganic fillers. The mass ratio of the inorganic fillers, curing agent to the epoxy resin is 1:(1.5 - 2.5):(5 - 10), and the curing is carried out at 60 °C.

[0017] Further, the curing agent is polyetheramine, and the inorganic filler is nano calcium carbonate with a particle size of 100 - 200 nm.

[0018] Further, the nano calcium carbonate is processed through the following steps:

[0019] S201. Ultrasonically disperse the nano calcium carbonate in deionized water, then add octylphenol polyoxyethylene ether, continuously stir for 0.5 - 1 h, add a mixed solution of stearic acid and absolute ethanol, heat to 50 - 75 °C and continue stirring for 1 - 2 h, and then perform centrifugal separation to obtain a crude product;

[0020] S202. After washing the crude product obtained by centrifugal separation in step S201 with sufficient absolute ethanol, perform vacuum drying at 20 - 30 °C for 4 - 6 h;

[0021] Further, the mass ratio of octylphenol polyoxyethylene ether, stearic acid, nano calcium carbonate, absolute ethanol, and deionized water in step S101 is 1:(10 - 40):(100 - 200):(500 - 800):(3000 - 5000).

[0022] A preparation method of a curing agent for enhancing the mechanical properties of soil includes the following steps:

[0023] S1. Mix red mud and slag in a certain proportion and calcine at 500 - 800 °C for 1 - 4 h;

[0024] S2. Incorporate modified nylon fibers into the red mud and slag calcined in step S1 in a certain proportion and continuously stir in a blender for 10 min to obtain a curing agent.

[0025] An application of a curing agent for enhancing the mechanical properties of soil in the solidification of lead - contaminated soil.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The curing agent prepared by the present invention uses solid wastes such as red mud and slag as raw materials, improving the utilization of solid wastes. By adding nylon fibers in the present invention, the strength of the solidified soil is effectively improved;

[0028] 2. The modified nylon fiber used in the present invention is compounded with graphene, further improving the solidification strength of the soil. Its outer side is impregnated with epoxy resin, and the epoxy resin contains inorganic fillers, increasing the internal friction angle and cohesion of the soil, thereby further enhancing the mechanical properties of the soil. Description of the Drawings

[0029] Figure 1 is the process flow chart for preparing the curing agent of the present invention;

[0030] Figure 2 is the process flow chart for preparing the modified nylon fiber of the present invention;

[0031] Figure 3This is the process flow diagram of the treatment process of nano calcium carbonate in the present invention. Specific embodiments

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] Please refer to Figures 1 to 3 , the present invention provides:

[0034] Example 1

[0035] A preparation method of a curing agent for enhancing the mechanical properties of soil, comprising the following steps:

[0036] S1. Mix 12 g of red mud and 35 g of slag in proportion and calcine at 700 °C for 3.5 h;

[0037] S2. Incorporate 5 g of modified nylon fiber into the red mud and slag calcined in step S1, and continuously stir in a blender for 10 min to obtain a curing agent;

[0038] The above-mentioned modified nylon fiber is prepared by the following steps:

[0039] S101. Put 6.4 g of nylon fiber into a mixed solution of calcium chloride with a concentration of 3 mol / L and copper chloride with a concentration of 1 mol / L, heat to 55 °C and soak for 1.5 h. The amount of the mixed solution of calcium chloride and copper chloride is 225 g. Then take out the nylon fiber and wash it with sufficient deionized water. The washed nylon fiber is vacuum dried at 30 °C for 4 h for the first time;

[0040] S102. Put 5.8 g of nylon fiber vacuum dried for the first time in step S101 into a sodium hydroxide solution with a concentration of 3 mol / L and soak for 0.8 h. The amount of the sodium hydroxide solution is 212 g. After soaking, wash it with sufficient deionized water and vacuum dry it at 55 °C for 1.2 h for the second time;

[0041] S103. Place 5.5 g of nylon fibers that have undergone secondary vacuum drying in step S102 into the graphene dispersion and stir magnetically for 2.5 h. Then, evaporate and dry the graphite dispersion at 60 °C until all the deionized water has evaporated to obtain pretreated nylon fibers. The graphene dispersion also includes polyvinylpyrrolidone, sodium carboxymethylcellulose, and sodium dodecylbenzenesulfonate. The dosage of sodium dodecylbenzenesulfonate is 0.015 g, the dosage of graphene is 0.6 g, the dosage of polyvinylpyrrolidone is 0.3 g, the dosage of sodium carboxymethylcellulose is 1.2 g, and the dosage of deionized water in the graphene solution is 22.5 g;

[0042] S104. Place the pretreated nylon fibers obtained in step S103 into epoxy resin for impregnation, and obtain modified nylon fibers after curing;

[0043] The epoxy resin in the above step S104 contains a curing agent and inorganic fillers. The mass ratio among the inorganic fillers, the curing agent, and the epoxy resin is 1:2:8. The curing agent is polyetheramine, and the curing is carried out at 60 °C;

[0044] The above curing agent is polyetheramine, and the inorganic filler is nano calcium carbonate. The particle size of the nano calcium carbonate is 150 nm;

[0045] The above nano calcium carbonate is processed through the following steps:

[0046] S201. Ultrasonically disperse 3.8 g of nano calcium carbonate into 98 g of deionized water, then add 0.025 g of octylphenol polyoxyethylene ether. After continuously stirring for 0.6 h, add a mixed solution of 0.75 g of stearic acid and 14 g of absolute ethanol, heat to 55 °C and continue stirring for 1.5 h, and then perform centrifugal separation to obtain a crude product;

[0047] S202. After washing the crude product obtained by centrifugal separation in step S201 with sufficient absolute ethanol, perform vacuum drying at 25 °C for 4.5 h.

[0048] Example 2

[0049] A preparation method of a curing agent for enhancing the mechanical properties of soil includes the following steps:

[0050] S1. Mix 10 g of red mud and 30 g of slag in proportion and calcine at 500 °C for 1 h;

[0051] S2. Incorporate 3 g of modified nylon fibers into the red mud and slag that have been calcined in step S1, and continuously stir in a blender for 10 min to obtain a curing agent;

[0052] The above modified nylon fibers are prepared through the following steps:

[0053] S101. Put 3.8 g of nylon fiber into a mixed solution of calcium chloride with a concentration of 2 mol / L and copper chloride with a concentration of 0.5 mol / L, heat it to 40 °C and soak for 0.5 h. The amount of the mixed solution of calcium chloride and copper chloride is 114 g. Then take out the nylon fiber and wash it with sufficient deionized water. The washed nylon fiber is vacuum dried at 20 °C for 2 h once;

[0054] S102. Put the 3.6 g of nylon fiber that has been vacuum dried once in step S101 into a sodium hydroxide solution with a concentration of 1 mol / L and soak for 0.5 h. The amount of the sodium hydroxide solution is 72 g. After soaking, wash it with sufficient deionized water and vacuum dry it at 40 °C for 1 h twice;

[0055] S103. Put the 3.4 g of nylon fiber that has been vacuum dried twice in step S102 into a graphene dispersion liquid and stir magnetically for 1 h. Then evaporate and dry the graphite dispersion liquid at 50 °C to completely evaporate the deionized water to obtain pretreated nylon fiber. The graphene dispersion liquid also includes polyvinylpyrrolidone, sodium carboxymethylcellulose and sodium dodecylbenzenesulfonate. The amount of sodium dodecylbenzenesulfonate is 0.034 g, the amount of graphene is 0.85 g, the amount of polyvinylpyrrolidone is 0.34 g, the amount of sodium carboxymethylcellulose is 0.34 g, and the amount of deionized water in the graphene dispersion liquid is 34 g;

[0056] S104. Put the pretreated nylon fiber obtained in step S103 into epoxy resin for impregnation, and obtain modified nylon fiber after curing;

[0057] The epoxy resin in the above step S104 contains a curing agent and an inorganic filler. The mass ratio between the inorganic filler, the curing agent and the epoxy resin is 1:1.5:5, and the curing is carried out at 60 °C;

[0058] The above curing agent is polyetheramine, and the inorganic filler is nano calcium carbonate, and the particle size of the nano calcium carbonate is 100 nm;

[0059] The above nano calcium carbonate is processed through the following steps:

[0060] S201. Ultrasonically disperse 3.8 g of nano calcium carbonate into 114 g of deionized water, then add 0.038 g of octylphenol polyoxyethylene ether, continuously stir for 0.5 h, add a mixed solution of 0.38 g of stearic acid and 19 g of absolute ethanol, heat to 50 °C and continue to stir for 1 h, and then centrifuge to obtain a crude product;

[0061] S202. After washing the crude product obtained by centrifugation in step S201 with sufficient absolute ethanol, vacuum dry it at 20 °C for 4 h.

[0062] Example 3

[0063] A preparation method of a curing agent for enhancing the mechanical properties of soil, comprising the following steps:

[0064] S1. Mix 15 g of red mud and 40 g of slag in proportion and calcine at 800 °C for 4 h;

[0065] S2. Incorporate 6 g of modified nylon fiber into the red mud and slag calcined in step S1, and continuously stir in a blender for 10 min to obtain the curing agent;

[0066] The above-mentioned modified nylon fiber is prepared through the following steps:

[0067] S101. Put 7.8 g of nylon fiber into a mixed solution of calcium chloride with a concentration of 4 mol / L and copper chloride with a concentration of 2 mol / L, heat to 60 °C and soak for 2 h. The amount of the mixed solution of calcium chloride and copper chloride is 390 g. Then take out the nylon fiber and wash it with sufficient deionized water. The washed nylon fiber is vacuum-dried at 40 °C for 5 h for the first time;

[0068] S102. Put 6.9 g of nylon fiber vacuum-dried for the first time in step S101 into a sodium hydroxide solution with a concentration of 4 mol / L and soak for 1 h. The amount of the sodium hydroxide solution is 345 g. After soaking, wash it with sufficient deionized water and vacuum-dry it at 80 °C for 2 h for the second time;

[0069] S103. Put 6.2 g of nylon fiber vacuum-dried for the second time in step S102 into a graphene dispersion liquid and stir magnetically for 3 h. Then evaporate and dry the graphite dispersion liquid at 80 °C until the deionized water is completely evaporated to obtain pretreated nylon fiber. The graphene dispersion liquid also includes polyvinylpyrrolidone, sodium carboxymethylcellulose and sodium dodecylbenzenesulfonate. The amount of sodium dodecylbenzenesulfonate is 0.0124 g, the amount of graphene is 0.62 g, the amount of polyvinylpyrrolidone is 0.62 g, the amount of sodium carboxymethylcellulose is 1.24 g, and the amount of deionized water in the graphene dispersion liquid is 24.8 g;

[0070] S104. Put the pretreated nylon fiber obtained in step S103 into epoxy resin for impregnation, and obtain the modified nylon fiber after curing;

[0071] The epoxy resin in the above step S104 contains a curing agent and an inorganic filler. The mass ratio between the inorganic filler, the curing agent and the epoxy resin is 1:2.5:10, and the curing is carried out at 60 °C;

[0072] The curing agent is polyetheramine, and the inorganic filler is nano calcium carbonate with a particle size of 200 nm;

[0073] The above nano calcium carbonate is processed through the following steps:

[0074] S201. Ultrasonically disperse 4.6 g of nano calcium carbonate into 115 g of deionized water, then add 0.023 g of octylphenol polyoxyethylene ether. After continuously stirring for 1 h, add a mixed solution of 0.92 g of stearic acid and 18.4 g of absolute ethanol, heat to 75 °C and continue stirring for 2 h, and then centrifuge to obtain the crude product;

[0075] S202. Wash the crude product obtained by centrifugation in step S201 with sufficient absolute ethanol, and then vacuum dry it at 30 °C for 6 h.

[0076] Example 4

[0077] A preparation method of a curing agent for enhancing the mechanical properties of soil, comprising the following steps:

[0078] S1. Mix 14 g of red mud and 32 g of slag in proportion and calcine at 600 °C for 2.5 h;

[0079] S2. Incorporate 4.5 g of modified nylon fiber into the red mud and slag calcined in step S1, and continuously stir in a blender for 10 min to obtain the curing agent;

[0080] The above-mentioned modified nylon fiber is prepared through the following steps:

[0081] S101. Put 6.8 g of nylon fiber into a mixed solution of calcium chloride with a concentration of 3 mol / L and copper chloride with a concentration of 1.5 mol / L, heat to 50 °C and soak for 0.8 h. The amount of the mixed solution of calcium chloride and copper chloride is 275 g. Then take out the nylon fiber and wash it with sufficient deionized water. The washed nylon fiber is vacuum dried at 30 °C for 3.5 h for the first time;

[0082] S102. Put 5.8 g of nylon fiber that has been vacuum dried for the first time in step S101 into a sodium hydroxide solution with a concentration of 3 mol / L and soak for 1 h. The amount of the sodium hydroxide solution is 208 g. After soaking, wash it with sufficient deionized water and vacuum dry it at 55 °C for 2 h for the second time;

[0083] S103. Place 5.2 g of nylon fiber that has been vacuum dried for the second time in step S102 in the graphene dispersion and stir magnetically for 2 h. Then evaporate and dry the graphite dispersion at 65 °C until the deionized water is completely evaporated to obtain the pretreated nylon fiber. The graphene dispersion also includes polyvinylpyrrolidone, sodium carboxymethyl cellulose, and sodium dodecylbenzenesulfonate. The amount of sodium dodecylbenzenesulfonate is 0.017 g, the amount of graphene is 0.77 g, the amount of polyvinylpyrrolidone is 0.59 g, the amount of sodium carboxymethyl cellulose is 1.36 g, and the amount of deionized water in the graphene dispersion is 30.6 g;

[0084] S104. Immerse the pretreated nylon fibers obtained in step S103 into epoxy resin, and after curing, obtain modified nylon fibers;

[0085] The epoxy resin in the above step S104 contains a curing agent and inorganic fillers, and the mass ratio among the inorganic fillers, the curing agent and the epoxy resin is 1:2:8, and the curing is carried out at 60 °C;

[0086] The above curing agent is polyetheramine, and the inorganic filler is nano calcium carbonate, and the particle size of the nano calcium carbonate is 200 nm;

[0087] The above nano calcium carbonate is processed through the following steps:

[0088] S201. Ultrasonically disperse 4.2 g of nano calcium carbonate into 125 g of deionized water, then add 0.028 g of octylphenol polyoxyethylene ether, continuously stir for 0.7 h, add a mixed solution of 0.98 g of stearic acid and 18.2 g of absolute ethanol, heat to 66 °C and continue to stir for 1.4 h, and then perform centrifugal separation to obtain a crude product;

[0089] S202. After washing the crude product obtained by centrifugal separation in step S201 with sufficient absolute ethanol, perform vacuum drying at 20 °C for 5 h.

[0090] Comparative Example 1

[0091] The difference between Comparative Example 1 and Example 1 is that step S101 is omitted in the preparation of the modified nylon fibers, and the remaining steps are exactly the same as those in Example 1.

[0092] Comparative Example 2

[0093] The difference between Comparative Example 2 and Example 1 is that step S102 is omitted in the preparation of the modified nylon fibers, and the remaining steps are exactly the same as those in Example 1.

[0094] Comparative Example 3

[0095] The difference between Comparative Example 3 and Example 1 is that step S103 is omitted in the preparation of the modified nylon fibers, and the remaining steps are exactly the same as those in Example 1.

[0096] Comparative Example 4

[0097] The difference between Comparative Example 4 and Example 1 is that the treatment process of the nano calcium carbonate through step S201 and step S202 is cancelled in the epoxy resin, and the remaining steps are exactly the same as those in Example 1.

[0098] Comparative Example 5

[0099] The difference between Comparative Example 5 and Example 1 is that the addition of the nano calcium carbonate is completely cancelled in the epoxy resin, and the remaining steps are exactly the same as those in Example 1.

[0100] The components of the red mud and slag used in the examples and comparative examples of the present invention are shown in Table 1 below:

[0101] Table 1: Composition Table of Red Mud and Slag

[0102] CaO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> MgO <![CDATA[SO3]]> <![CDATA[Na2O]]> Others Red mud 6.18 21.69 20.49 37.96 0.63 0.41 6.32 6.32 Slag 42.68 28.97 14.87 0.39 7.64 2.53 0.53 2.39

[0103] The red mud used in the present invention is Bayer red mud. The selected red mud passes through a 1 mm sieve. The slag selected has a surface area greater than 400 m 2 / kg of S95 grade slag. The average length of the nylon fibers used is 2 cm, and the average diameter is 0.7 mm.

[0104] A total of 9 groups of solidifying agents were prepared through Examples 1-4 and Comparative Examples 1-5. Using these 9 groups of solidifying agents, a simulation test was carried out on lead-contaminated loess. The specific test process is as follows:

[0105] For each group of loess, take 320 g, 5 g of lead nitrate, and 70 g of deionized water. Dissolve the lead nitrate in the deionized water and pour it into each group of loess respectively. The loess used is taken from Dongshan in Taiyuan, with a maximum dry density of 1.81, an optimum moisture content of 20.8, a liquid limit of 30.3, and a plastic limit of 11.5. After stirring evenly, put it into a sealed bag and let it stand for 14 days to be used as the simulated high-concentration lead-contaminated soil in this experiment;

[0106] Respectively take 9 groups of the above lead-contaminated loess and add the 9 groups of solidifying agents prepared in Examples 1-4 and Comparative Examples 1-5. The weight of the solidifying agent added to each group is 40 g, and stir evenly; then use an electric hydraulic demolding machine to prepare cylindrical specimens by the static pressure forming method; after static pressure forming, wait for 1 hour to demold, put it into a polyethylene sealed bag (to avoid moisture loss), and transfer it to a curing box with a temperature of 20 °C and a relative humidity not lower than 90% for standard curing. The curing age is 28 days and 90 days; after the curing is completed, conduct an unconfined compressive strength test;

[0107] An unconfined compressive strength test was carried out on the solidified soil with curing ages of 28 d and 90 d. The test standard is ASTM D4219. The test uses a YHS-229WJ-50kN electronic universal testing machine, and the axial strain rate is controlled at 1 mm / min; the test results are shown in Table 2 below:

[0108] Table 2: Unconfined Compressive Strength Test Table of 9 Groups of Lead-Contaminated Loess Added with Solidifying Agents Prepared in Examples 1-4 and Comparative Examples 1-5 at 28 d and 90 d

[0109] Unconfined compressive strength at 28d (MPa) Unconfined compressive strength at 90d (MPa) Example 1 0.438 0.764 Example 2 0.416 0.715 Example 3 0.404 0.723 Example 4 0.449 0.759 Comparative Example 1 0.376 0.618 Comparative Example 2 0.381 0.633 Comparative Example 3 0.345 0.578 Comparative Example 4 0.352 0.571 Comparative Example 5 0.308 0.517

[0110] From the data of Example 1 and Comparative Examples 1-2 in Table 2 above, it can be seen that after the nylon fiber is treated in steps S101 and S102 of the present invention, the reinforcement effect of the nylon fiber in the soil is effectively improved; from the data of Example 1 and Comparative Example 3, it can be seen that the nylon fiber also improves its reinforcement effect in the soil after being compounded with graphene; in the present invention, the outer layer of the nylon fiber is impregnated with epoxy resin, and the epoxy resin coats the nylon fiber, improving the bonding effect between the nylon fiber and graphene. In addition, inorganic fillers are provided in the epoxy resin. From the comparison between Comparative Examples 4-5 and Example 1, it can be seen that the addition of inorganic fillers further improves the reinforcement effect of the modified nylon fiber on the soil.

[0111] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A curing agent for enhancing the mechanical properties of soil, characterized in that, It comprises the following components by mass parts: 10 - 15 parts of red mud, 30 - 40 parts of slag, and 3 - 6 parts of modified nylon fiber; The preparation method of the modified nylon fiber comprises the following steps: S101. Put the nylon fiber into a mixed solution of calcium chloride with a concentration of 2 - 4 mol / L and copper chloride with a concentration of 0.5 - 2 mol / L, heat it to 40 - 60 °C and soak for 0.5 - 2 h. Then take out the nylon fiber and wash it with sufficient deionized water. The washed nylon fiber is vacuum-dried for 2 - 5 h at 20 - 40 °C for the first time; S102. Put the nylon fiber that has been vacuum-dried for the first time in step S101 into a sodium hydroxide solution with a concentration of 1 - 4 mol / L and soak for 0.5 - 1 h. After soaking, wash it with sufficient deionized water and vacuum-dry it for 1 - 2 h at 40 - 80 °C for the second time; S103. Place the nylon fiber that has been vacuum-dried for the second time in step S102 in the graphene dispersion and stir magnetically for 1 - 3 h. Then evaporate and dry the graphite dispersion at 50 - 80 °C until the deionized water is completely evaporated to obtain the pretreated nylon fiber. The graphene dispersion also includes polyvinylpyrrolidone, sodium carboxymethylcellulose, and sodium dodecylbenzenesulfonate; S104. Put the pretreated nylon fiber obtained in step S103 into epoxy resin for impregnation, and obtain the modified nylon fiber after curing.

2. The curing agent for enhancing the mechanical properties of soil according to claim 1, characterized in that In step S101, the mass ratio between the nylon fiber and the mixed solution of calcium chloride and copper chloride is 1:(30 - 50).

3. The curing agent for enhancing the mechanical properties of soil according to claim 1, characterized in that, In step S102, the mass ratio between the nylon fiber that has been vacuum-dried for the first time in step S101 and the sodium hydroxide solution is 1:(20 - 50).

4. The curing agent for enhancing the mechanical properties of soil according to claim 1, characterized in that In step S103, the mass ratio between sodium dodecylbenzenesulfonate, graphene, polyvinylpyrrolidone, sodium carboxymethylcellulose, deionized water in the graphene dispersion and the nylon fiber that has been vacuum-dried for the second time in step S102 and added to the graphene dispersion is 1:(25 - 50):(10 - 50):(10 - 100):(1000 - 2000):(100 - 500).

5. The curing agent for enhancing the mechanical properties of soil according to claim 1, characterized in that, The epoxy resin in step S104 contains a curing agent and inorganic filler. Among them, the mass ratio between the inorganic filler, the curing agent and the epoxy resin is 1:(1.5 - 2.5):(5 - 10), and the curing is carried out at 60 °C.

6. The curing agent for enhancing the mechanical properties of soil according to claim 5, wherein The curing agent is polyetheramine, and the inorganic filler is nano calcium carbonate with a particle size of 100 - 200 nm.

7. The curing agent for enhancing the mechanical properties of soil according to claim 6, characterized in that, The nano calcium carbonate is processed through the following steps: S201. Ultrasonically disperse the nano calcium carbonate into deionized water, then add octylphenol polyoxyethylene ether. After continuously stirring for 0.5 - 1 h, add a mixed solution of stearic acid and absolute ethanol, heat to 50 - 75 °C and continue stirring for 1 - 2 h, and then centrifuge to obtain the crude product; S202. After washing the crude product obtained by centrifugation in step S201 with sufficient absolute ethanol, vacuum-dry it at 20 - 30 °C for 4 - 6 h.

8. The curing agent for enhancing the mechanical properties of soil according to claim 7, characterized in that, In the step S101, the mass ratio between octylphenol polyoxyethylene ether, stearic acid, nano calcium carbonate, absolute ethanol and deionized water is 1:(10 - 40):(100 - 200):(500 - 800):(3000 - 5000).

9. A preparation method of a curing agent for enhancing the mechanical properties of soil as described in any one of claims 1 - 8, characterized in that, The method comprises the following steps: S1. Mix red mud and slag in proportion and calcine at 500 - 800 °C for 1 - 4 h; S2. Incorporate modified nylon fibers into the red mud and slag calcined in step S1 in proportion, and continuously stir in a blender for 10 min to obtain a curing agent.

10. Application of a curing agent for enhancing the mechanical properties of soil according to any one of claims 1 - 8 in the solidification of lead - contaminated soil.

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