High-strength phosphogypsum roadbed material and preparation method thereof

Abstract

The application discloses a high-strength phosphogypsum roadbed material and a preparation method thereof, and relates to the technical field of roadbed materials.The method first carries out ultrasonic-assisted chelation purification on phosphogypsum, and then generates a magnesium-aluminum layered double hydroxide coating layer on the surface of the phosphogypsum through in-situ reaction, so as to realize deep passivation and stabilization of impurities.Meanwhile, graphene oxide-polymer nanohybrid reinforcing liquid is prepared, and basalt fibers are subjected to mild acid etching activation.Finally, modified phosphogypsum, slag powder, cement, activated fibers and nanohybrid reinforcing liquid and other components are mixed, stirred, pressed and formed according to a specific process and are maintained.The method remarkably improves the strength and structural stability of the phosphogypsum matrix through multi-step collaborative modification, and realizes high-value resource utilization of the phosphogypsum in roadbed engineering.

Description

Technical Field

[0001] This invention relates to the field of roadbed material technology, specifically to a high-strength phosphogypsum roadbed material and its preparation method. Background Technology

[0002] Phosphogypsum is a major industrial byproduct produced during the production of phosphate fertilizers. Its annual output is huge, and for a long time it has been mainly disposed of by open-air dumping. This not only occupies a lot of land resources, but also makes it easy for harmful components such as phosphorus, fluorine and heavy metals to migrate and spread due to rainwater leaching, causing a series of environmental problems such as soil pollution and water pollution. Therefore, the resource utilization of phosphogypsum has become an urgent industry problem to be solved. As a key consumable in transportation infrastructure construction, roadbed materials are in huge demand. Utilizing phosphogypsum as a resource for roadbed material production is one of the effective ways to achieve large-scale utilization. However, phosphogypsum itself has inherent defects such as low strength, poor water resistance, and poor volume stability. Furthermore, impurities such as eutectic phosphorus, fluorine, and heavy metals remaining on its surface further degrade the material's performance, limiting its direct application as a roadbed material. Although existing technologies have attempted to modify phosphogypsum by adding cement, slag, or other cementing materials, or to improve its performance through simple acid-base treatment or the addition of conventional admixtures, the modification effects are generally limited, making it difficult to significantly improve the mechanical strength of roadbed materials, thus failing to meet the stringent requirements of actual engineering construction for roadbed materials. Summary of the Invention

[0003] The purpose of this invention is to provide a high-strength phosphogypsum roadbed material and its preparation method, so as to solve the technical problem of insufficient mechanical strength of phosphogypsum roadbed materials mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A method for preparing a high-strength phosphogypsum roadbed material includes the following steps:

[0006] S1. Mix phosphogypsum, ethylenediaminetetramethylenephosphonic acid, aminotrimethylphosphonic acid and deionized water, and then subject the mixture to ultrasonic treatment and mechanical stirring to obtain a suspension.

[0007] S2. Add magnesium nitrate hexahydrate and aluminum nitrate nonahydrate to the suspension, stir and add sodium hydroxide solution dropwise to maintain the pH value of the system. After the reaction, filter and dry to obtain modified phosphogypsum.

[0008] S3. Mix the graphene oxide dispersion with carboxylated styrene-butadiene pyridine emulsion and silane coupling agent KH-550, add triethylamine to adjust the pH value and react to obtain the nano-hybrid enhancement solution;

[0009] S4. Immerse the basalt fiber in citric acid solution for acid etching, rinse and dry to obtain acid-etched basalt fiber;

[0010] S5. Mix the modified phosphogypsum, slag powder, cement and acid-etched basalt fiber evenly, then add phytic acid and polyethylene glycol and continue stirring. Finally, add the nano-hybrid reinforcing liquid and mix, then add water and continue stirring to obtain the mixture.

[0011] S6. Press the mixture into shape and then cure it to obtain high-strength phosphogypsum roadbed material.

[0012] In this invention, the mechanical strength of phosphogypsum subgrade material is synergistically improved from the following aspects: Firstly, by utilizing the cavitation effect of ultrasound combined with the strong coordination effect of a low-concentration chelating agent, the eutectic phosphorus, fluorine, and organic matter "impurity coatings" on the surface of phosphogypsum crystals are peeled off and sealed, exposing highly active dihydrate gypsum crystal faces, thereby eliminating the chemical poisoning effect of impurities on the hydration process of the cementitious system. Then, a magnesium-aluminum layered double hydroxide nano-protective layer is grown on the gypsum surface through in-situ synthesis technology. This process utilizes the anion exchange characteristics of LDHs to fix residual harmful ions within the interlayer lattice and reconstructs the originally smooth gypsum surface into a nanoscale rough structure with a high specific surface area. This transformation not only provides a large number of heterogeneous nucleation sites for subsequent cement hydration products but also significantly enhances the interfacial shear strength between phosphogypsum particles and the cementitious matrix through the dual effects of physical interlocking and chemical bonding. This ensures that the interfacial transition zone is no longer a weak point under pressure, thus achieving a significant improvement in overall compressive strength in both early and later stages. On the other hand, a hybrid nano-reinforcing liquid is formed by chemically grafting graphene oxide and carboxylated styrene-butadiene-pyridine emulsion using the silane coupling agent KH-550. The oxygen-containing groups on the surface of graphene oxide not only act as "molecular-level templates" to guide the hydration products to grow directionally along its high-modulus sheets, forming a regular needle-like reinforcing structure, but also form elastic connections between microcracks through the flexible bridging effect of polymer long chains. At the same time, basalt fibers, which have been gently activated by citric acid, form a strong mechanical anchor with the above-mentioned nano-hybrid liquid and cementitious matrix due to the micro- and nano-etched pits on their surface. When the material is subjected to external forces, the highly dense products induced by the graphene template are responsible for bearing the compressive stress, while the uniformly distributed and interface-stable basalt fibers dissipate energy to block the penetrating growth of microcracks. This "rigid-flexible" multi-scale reinforcement system enables the phosphogypsum roadbed material to have excellent fatigue resistance and overall structural stability while ensuring ultra-high compressive strength.

[0013] Researchers discovered in experiments that the surface of the magnesium-aluminum layered double hydroxide layer carries a positive charge, while the surfaces of graphene oxide and carboxylated styrene-butadiene-pyridine emulsion carry a negative charge. When these two come into contact, a transient localized flocculation phenomenon occurs due to extremely strong electrostatic attraction. This flocculation transforms the originally "single-layered spread" GO sheets, which have an ultra-high specific surface area, into "multi-layered agglomerates," causing them to lose their function as nanotemplates to induce the directional growth of hydration products, resulting in disordered crystal arrangement within the matrix. Simultaneously, the flocculation-induced agglomerates form macroscopic physical discontinuities within the material. These agglomerates have a loose structure and extremely poor interfacial bonding with the matrix, becoming stress concentration centers under pressure, inducing premature initiation and rapid propagation of microcracks. This, in turn, affects the improvement of the mechanical strength of phosphogypsum roadbed materials. To address this technical challenge, an interfacial buffer system composed of polyethylene glycol (PEG) and phytic acid was developed. The steric hindrance effect of PEG effectively shields electrostatic attraction, ensuring uniform spreading of graphene oxide on the surface of phosphogypsum particles to restore its nanotemplate-inducing function. Simultaneously, the strong chelating and bridging effects of phytic acid are utilized to construct a covalent "molecular lock" between the double hydroxide layer and the nano-reinforcing phase. This transforms unstable physical adsorption into high-strength chemical bonding, completely eliminating stress concentration defects caused by flocculation. Furthermore, by inducing hydration products to form a dense three-dimensional cross-linked network, the overall compressive strength and structural durability of the phosphogypsum roadbed material are further enhanced.

[0014] Preferably, in step S1, the mass ratio of ethylenediaminetetramethylenephosphonic acid to aminotrimethylphosphonic acid is 10:(4-6).

[0015] Preferably, in step S2, the mass ratio of magnesium nitrate hexahydrate to aluminum nitrate nonahydrate is 30:(13-15).

[0016] Preferably, in step S2, the reaction temperature is 60-65°C and the reaction time is 3-5 hours.

[0017] Preferably, in step S3, triethylamine is added to adjust the pH value to 8-8.5.

[0018] Preferably, in step S3, the reaction temperature is 55–60°C and the reaction time is 2–5 hours.

[0019] Preferably, in step S4, the mass concentration of the citric acid solution is 0.3 to 0.6 wt%.

[0020] Preferably, in step S5, the mass ratio of slag powder to cement is 12:(4-6).

[0021] Preferably, in step S5, the mass ratio of phytic acid to polyethylene glycol is 4:(2-3).

[0022] A high-strength phosphogypsum roadbed material is prepared by the method described above.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. Impurities on the surface of phosphogypsum are removed by ultrasound and chelating agents, and a magnesium-aluminum layered double hydroxide nano-protective layer is generated in situ. This not only fixes harmful ions but also transforms the gypsum surface into a rough structure with a high specific surface area. This significantly enhances the interfacial bonding force between the phosphogypsum particles and the cementitious matrix, resulting in a significant improvement in both the early and later compressive strength of the material.

[0025] 2. A nano-hybrid liquid formed by graphene oxide and polymers is used as a template to guide the directional growth of hydration products, forming a dense structure. Simultaneously, acid-etched basalt fibers prevent the propagation of microcracks through mechanical anchoring. This synergistic effect enables the material to possess high compressive strength while also exhibiting excellent fatigue resistance and structural stability.

[0026] 3. By introducing polyethylene glycol and phytic acid as interfacial buffers, the flocculation problem caused by electrostatic attraction of nano-reinforcing materials is effectively avoided, ensuring uniform dispersion of graphene oxide and its template function. Simultaneously, phytic acid forms strong chemical bonds at the interface, eliminating stress concentration points and further improving the overall strength and durability of the material. Attached Figure Description

[0027] Figure 1 This is a SEM image of the surface of the high-strength phosphogypsum roadbed material prepared in Example 4 of the present invention after demolding and curing.

[0028] Figure 2 XPS images of the high-strength phosphogypsum roadbed material prepared in Example 4 of this invention after demolding and curing. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] A method for preparing a high-strength phosphogypsum roadbed material includes the following steps:

[0032] Step 1: Take 10.0 kg of raw phosphogypsum dried to constant weight and place it in an ultrasonic reactor containing 15.0 L of deionized water. Add 10.0 g of ethylenediaminetetramethylenephosphonic acid and 5.5 g of aminotrimethylphosphonic acid. While performing ultrasonic treatment (frequency set to 45 kHz, power 800 W), simultaneously treat with low-speed mechanical stirring at 40 °C for 30 min to obtain a suspension.

[0033] Step 2: Add 300.0 g of magnesium nitrate hexahydrate and 145.0 g of aluminum nitrate nonahydrate to the above suspension, and start high-speed stirring (500 rpm); slowly add 2 mol / L NaOH solution, maintain the pH of the system at 10.2±0.1, and react at 63℃ for 4.5 h. After the reaction is completed, perform vacuum filtration and dry at 60℃ for 12 h to obtain modified phosphogypsum;

[0034] Step 3: Take 100.0 g of 1% (w / w) graphene oxide (GO) dispersion and mix it with 400.0 g of carboxylated styrene-butadiene pyridine emulsion (50% solid content). Add 4.0 g of silane coupling agent KH-550 and add an appropriate amount of triethylamine to adjust the pH to 8.3 to maintain system stability. Place the mixture in a 58℃ constant temperature water bath and reflux at 300 rpm for 3 h to obtain a nano-hybridized enhanced solution.

[0035] Step 4: Weigh 150.0 g of basalt fiber (12 mm in length), immerse it completely in a 0.5% citric acid solution, let it stand and soak for 15 min at room temperature, rinse with deionized water until neutral, and dry in an oven at 105℃ to obtain acid-etched basalt fiber.

[0036] Step 5: Place the modified phosphogypsum obtained in Step 2, 1.2 kg of S95 grade slag powder, 0.55 kg of PO 42.5 cement, and the acid-etched basalt fiber obtained in Step 4 into a mixer. First, spray in a solution consisting of 20.0 g of phytic acid and 14.0 g of polyethylene glycol (PEG-400) and dry mix for 3 min. Then, spray in the hybrid reinforcing liquid prepared in Step 3 and 1.1 kg of water while continuously stirring. Continue high-speed stirring for 8 min to obtain high-strength phosphogypsum subgrade material.

[0037] Example 2

[0038] A method for preparing a high-strength phosphogypsum roadbed material includes the following steps:

[0039] Step 1: Take 10.0 kg of raw phosphogypsum dried to constant weight and place it in an ultrasonic reactor containing 15.0 L of deionized water. Add 10.0 g of ethylenediaminetetramethylenephosphonic acid and 4.5 g of aminotrimethylphosphonic acid. While performing ultrasonic treatment (frequency set to 45 kHz, power 800 W), simultaneously treat with low-speed mechanical stirring at 40 °C for 30 min to obtain a suspension.

[0040] Step 2: Add 300.0 g of magnesium nitrate hexahydrate and 135.0 g of aluminum nitrate nonahydrate to the above suspension, start high-speed stirring (500 rpm); slowly add 2 mol / L NaOH solution, maintain the pH of the system at 10.2 ± 0.1, react at 63℃ for 4 h, after the reaction is completed, perform vacuum filtration and dry at 60℃ for 12 h to obtain modified phosphogypsum;

[0041] Step 3: Take 100.0 g of 1% (w / w) graphene oxide (GO) dispersion and mix it with 400.0 g of carboxylated styrene-butadiene pyridine emulsion (50% solid content). Add 4.0 g of silane coupling agent KH-550 and add an appropriate amount of triethylamine to adjust the pH to 8.3 to maintain system stability. Place the mixture in a 58℃ constant temperature water bath and reflux at 300 rpm for 3 h to obtain a nano-hybridized enhanced solution.

[0042] Step 4: Weigh 150.0 g of basalt fiber (12 mm in length), immerse it completely in a 0.4% citric acid solution, let it stand and soak for 15 min at room temperature, rinse with deionized water until neutral, and dry in an oven at 105℃ to obtain acid-etched basalt fiber.

[0043] Step 5: Place the modified phosphogypsum obtained in Step 2, 1.2 kg of S95 grade slag powder, 0.45 kg of PO 42.5 cement, and the acid-etched basalt fiber obtained in Step 4 into a mixer. First, spray in a solution consisting of 20.0 g of phytic acid and 12.0 g of polyethylene glycol (PEG-400) and dry mix for 3 min. Then, spray in the hybrid reinforcing liquid prepared in Step 3 and 1.1 kg of water while continuously stirring. Continue high-speed stirring for 8 min to obtain high-strength phosphogypsum subgrade material.

[0044] Example 3

[0045] A method for preparing a high-strength phosphogypsum roadbed material includes the following steps:

[0046] Step 1: Take 10.0 kg of raw phosphogypsum dried to constant weight and place it in an ultrasonic reactor containing 15.0 L of deionized water. Add 10.0 g of ethylenediaminetetramethylenephosphonic acid and 5.0 g of aminotrimethylphosphonic acid. While performing ultrasonic treatment (frequency set to 45 kHz, power 800 W), simultaneously treat with low-speed mechanical stirring at 40 °C for 30 min to obtain a suspension.

[0047] Step 2: Add 300.0 g of magnesium nitrate hexahydrate and 140.0 g of aluminum nitrate nonahydrate to the above suspension, start high-speed stirring (500 rpm); slowly add 2 mol / L NaOH solution, maintain the pH of the system at 10.2±0.1, react at 63℃ for 4 h, after the reaction is completed, perform vacuum filtration and dry at 60℃ for 12 h to obtain modified phosphogypsum;

[0048] Step 3: Take 100.0 g of 1% (w / w) graphene oxide (GO) dispersion and mix it with 400.0 g of carboxylated styrene-butadiene pyridine emulsion (50% solid content). Add 4.0 g of silane coupling agent KH-550 and add an appropriate amount of triethylamine to adjust the pH to 8.3 to maintain system stability. Place the mixture in a 58℃ constant temperature water bath and reflux at 300 rpm for 3.5 h to obtain a nano-hybridized enhanced solution.

[0049] Step 4: Weigh 150.0 g of basalt fiber (12 mm in length), immerse it completely in a 0.45% citric acid solution, let it stand and soak for 15 minutes at room temperature, rinse with deionized water until neutral, and dry in an oven at 105℃ to obtain acid-etched basalt fiber.

[0050] Step 5: Place the modified phosphogypsum obtained in Step 2, 1.2 kg of S95 grade slag powder, 0.5 kg of PO 42.5 cement, and the acid-etched basalt fiber obtained in Step 4 into a mixer. First, spray in a solution consisting of 20.0 g of phytic acid and 13.0 g of polyethylene glycol (PEG-400) and dry mix for 3 min. Then, spray in the hybrid reinforcing liquid prepared in Step 3 and 1.1 kg of water while continuously stirring. Continue high-speed stirring for 8 min to obtain high-strength phosphogypsum subgrade material.

[0051] Example 4

[0052] A method for preparing a high-strength phosphogypsum roadbed material includes the following steps:

[0053] Step 1: Take 10.0 kg of raw phosphogypsum dried to constant weight and place it in an ultrasonic reactor containing 15.0 L of deionized water. Add 10.0 g of ethylenediaminetetramethylenephosphonic acid and 6.0 g of aminotrimethylphosphonic acid. While performing ultrasonic treatment (frequency set to 45 kHz, power 800 W), simultaneously treat with low-speed mechanical stirring at 40 °C for 30 min to obtain a suspension.

[0054] Step 2: Add 300.0 g of magnesium nitrate hexahydrate and 150.0 g of aluminum nitrate nonahydrate to the above suspension, start high-speed stirring (500 rpm); slowly add 2 mol / L NaOH solution, maintain the pH of the system at 10.2 ± 0.1, react at 65℃ for 5 h, after the reaction is completed, perform vacuum filtration and dry at 60℃ for 12 h to obtain modified phosphogypsum;

[0055] Step 3: Take 100.0 g of 1% (w / w) graphene oxide (GO) dispersion and mix it with 400.0 g of carboxylated styrene-butadiene pyridine emulsion (50% solid content). Add 4.0 g of silane coupling agent KH-550 and add an appropriate amount of triethylamine to adjust the pH to 8.5 to maintain system stability. Place the mixture in a 60℃ constant temperature water bath and reflux at 300 rpm for 5 h to obtain a nano-hybridized enhanced solution.

[0056] Step 4: Weigh 150.0 g of basalt fiber (12 mm in length), immerse it completely in a 0.6% citric acid solution, let it stand and soak for 15 min at room temperature, rinse with deionized water until neutral, and dry in an oven at 105℃ to obtain acid-etched basalt fiber.

[0057] Step 5: Place the modified phosphogypsum obtained in Step 2, 1.2 kg of S95 grade slag powder, 0.6 kg of PO 42.5 cement, and the acid-etched basalt fiber obtained in Step 4 into a mixer. First, spray in a solution consisting of 20.0 g of phytic acid and 15.0 g of polyethylene glycol (PEG-400) and dry mix for 3 min. Then, spray in the hybrid reinforcing liquid prepared in Step 3 and 1.1 kg of water while continuously stirring. Continue high-speed stirring for 8 min to obtain high-strength phosphogypsum subgrade material.

[0058] Example 5

[0059] A method for preparing a high-strength phosphogypsum roadbed material includes the following steps:

[0060] Step 1: Take 10.0 kg of raw phosphogypsum dried to constant weight and place it in an ultrasonic reactor containing 15.0 L of deionized water. Add 10.0 g of ethylenediaminetetramethylenephosphonic acid and 4.0 g of aminotrimethylphosphonic acid. While performing ultrasonic treatment (frequency set to 45 kHz, power 800 W), simultaneously treat with low-speed mechanical stirring at 40 °C for 30 min to obtain a suspension.

[0061] Step 2: Add 300.0 g of magnesium nitrate hexahydrate and 130.0 g of aluminum nitrate nonahydrate to the above suspension, start high-speed stirring (500 rpm); slowly add 2 mol / L NaOH solution, maintain the pH of the system at 10.2 ± 0.1, react at 60℃ for 3 h, after the reaction is completed, perform vacuum filtration and dry at 60℃ for 12 h to obtain modified phosphogypsum;

[0062] Step 3: Take 100.0 g of 1% (w / w) graphene oxide (GO) dispersion and mix it with 400.0 g of carboxylated styrene-butadiene pyridine emulsion (50% solid content). Add 4.0 g of silane coupling agent KH-550 and add an appropriate amount of triethylamine to adjust the pH to 8.0 to maintain system stability. Place the mixture in a 55℃ constant temperature water bath and reflux at 300 rpm for 2 hours to obtain a nano-hybridized enhanced solution.

[0063] Step 4: Weigh 150.0 g of basalt fiber (12 mm in length), immerse it completely in a 0.3% citric acid solution, let it stand and soak for 15 min at room temperature, rinse with deionized water until neutral, and dry in an oven at 105℃ to obtain acid-etched basalt fiber.

[0064] Step 5: Place the modified phosphogypsum obtained in Step 2, 1.2 kg of S95 grade slag powder, 0.4 kg of PO 42.5 cement, and the acid-etched basalt fiber obtained in Step 4 into a mixer. First, spray in a solution consisting of 20.0 g of phytic acid and 10.0 g of polyethylene glycol (PEG-400) and dry mix for 3 min. Then, spray in the hybrid reinforcing liquid prepared in Step 3 and 1.1 kg of water while continuously stirring. Continue high-speed stirring for 8 min to obtain high-strength phosphogypsum subgrade material.

[0065] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that steps 1 and 2 are omitted in the preparation process of phosphogypsum roadbed material, and the modified phosphogypsum in step 5 is replaced with the original phosphogypsum.

[0066] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that steps 3 and 4 are omitted in the preparation of phosphogypsum roadbed material, and hybrid reinforcing liquid and acid-etched basalt fiber are not added in step 5.

[0067] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that phytic acid and polyethylene glycol are not added in step 5 of the preparation process of phosphogypsum roadbed material.

[0068] Performance testing:

[0069] 1. Compressive Strength Test: The mixtures prepared in each embodiment and comparative example were placed into 100mm×100mm×100mm cubic molds and statically pressed under a pressure of 20MPa. They were then placed in a standard curing chamber at a temperature of 20±2℃ and a relative humidity of ≥95% for 7 days and 28 days, respectively. After curing, the compressive strength was tested using a microcomputer-controlled electro-hydraulic servo pressure testing machine. The loading rate was set to 0.5MPa / s. Each sample was tested in triplicate, and the average value was taken as the final compressive strength value. The test results are shown in Table 1.

[0070] 2. Flexural Strength Test: Following the "Test Procedures for Inorganic Binder Stabilized Materials in Highway Engineering," prism-shaped specimens (100mm × 100mm × 400mm) were prepared from the materials of each embodiment and comparative example. The curing conditions were the same as those for the compressive strength test (7 days and 28 days). The flexural strength was tested using the three-point bending method. The support span was set to 300mm, and the loading rate was 0.05MPa / s. Each sample was tested in triplicate, and the average value was taken as the final flexural strength value. The test results are shown in Table 1.

[0071] 3. Freeze-thaw resistance test: 100mm×100mm×100mm cubic specimens were selected after 28 days of curing. The initial mass (m0) and initial compressive strength (f0) of the specimens were first measured. Then, a rapid freeze-thaw cycle test was conducted. The freeze-thaw cycle parameters were set as follows: freezing temperature -20±2℃, freezing time 4h; thawing temperature 20±2℃, thawing time 4h, completing one freeze-thaw cycle. A total of 25 freeze-thaw cycles were performed. After each cycle, the remaining mass (m1) and remaining compressive strength (f1) of the specimens were measured. The mass loss rate ((m0-m1) / m0×100%) and strength loss rate ((f0-f1) / f0×100%) were calculated to evaluate the freeze-thaw resistance of the material. The test results are shown in Table 1.

[0072] Table 1:

[0073]

[0074] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-strength phosphogypsum road base material, characterized by, The method comprises the following steps: S1, mixing phosphogypsum, ethylenediamine tetramethylene phosphonic acid, amino trimethylene phosphonic acid and deionized water, and performing ultrasonic treatment and mechanical stirring to obtain a suspension; S2, adding magnesium nitrate hexahydrate and aluminum nitrate nonahydrate to the suspension, stirring and adding sodium hydroxide solution dropwise to maintain the pH value of the system, and performing filtration and drying after reaction to obtain modified phosphogypsum; S3, mixing graphene oxide dispersion liquid with carboxyl styrene butadiene emulsion and silane coupling agent KH-550, adding triethylamine to adjust the pH value and performing reaction to obtain a nano hybrid reinforcing liquid; S4, immersing basalt fiber in a citric acid solution for acid etching, rinsing and drying to obtain acid-etched basalt fiber; S5, mixing modified phosphogypsum, slag powder, cement and acid-etched basalt fiber, and stirring uniformly, then adding phytic acid and polyethylene glycol to continue stirring, finally adding the nano hybrid reinforcing liquid to mix and stir, and adding water to continue stirring to obtain a high-strength phosphogypsum roadbed material.

2. The method of claim 1, wherein the high-strength phosphogypsum road base material is prepared by adding 0.1 to 0.5 parts by weight of the dispersant to 100 parts by weight of the phosphogypsum. In the step S1, the mass ratio of ethylenediamine tetramethylene phosphonic acid to amino trimethylene phosphonic acid is 10:(4-6).

3. The method of claim 1, wherein the high-strength phosphogypsum road base material is prepared by adding 0.1 to 0.5 parts by weight of the dispersant to 100 parts by weight of the phosphogypsum. In the step S2, the mass ratio of magnesium nitrate hexahydrate to aluminum nitrate nonahydrate is 30:(13-15).

4. The method of claim 1, wherein the high-strength phosphogypsum road base material is prepared by adding 0.1 to 0.5 parts by weight of the dispersant to 100 parts by weight of the phosphogypsum. In the step S2, the reaction temperature is 60-65℃, and the reaction time is 3-5h.

5. The method of claim 1, wherein the high-strength phosphogypsum road base material is prepared by adding 0.1 to 0.5 parts by weight of the dispersant to 100 parts by weight of the phosphogypsum. In the step S3, triethylamine is added to adjust the pH value to 8-8.

5.

6. The method of claim 1, wherein the high-strength phosphogypsum road base material is prepared by mixing 70 to 90 wt% of the phosphogypsum, 5 to 20 wt% of the cement, and 1 to 10 wt% of the superplasticizer. In the step S3, the reaction temperature is 55-60℃, and the reaction time is 2-5h.

7. The method of claim 1, wherein the high-strength phosphogypsum road base material is prepared by mixing 70 to 90 wt% of the phosphogypsum, 5 to 20 wt% of the cement, and 1 to 10 wt% of the superplasticizer. In the step S4, the mass concentration of the citric acid solution is 0.3-0.6wt%.

8. The method of claim 1, wherein the high-strength phosphogypsum road base material is prepared by adding 0.1 to 0.5 parts by weight of the dispersant to 100 parts by weight of the phosphogypsum. In the step S5, the mass ratio of slag powder to cement is 12:(4-6).

9. The method of claim 1, wherein the high-strength phosphogypsum road base material is prepared by mixing 70 to 90 wt% of the phosphogypsum, 5 to 20 wt% of the cement, and 1 to 10 wt% of the superplasticizer. In the step S5, the mass ratio of phytic acid to polyethylene glycol is 4:(2-3).

10. A high-strength phosphogypsum road base material, characterized by, Prepared by the method of any one of claims 1-9.

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