Phosphogypsum rapid grouting forming road stable base and preparation method thereof

Abstract

The present application relates to the technical field of bulk solid waste and road, and provides a phosphogypsum rapid grouting forming road stable base and a preparation method thereof, the preparation method comprising: paving phosphogypsum ceramsite with a softening coefficient greater than or equal to 85%, to form a road stable base aggregate skeleton with a skeleton porosity greater than or equal to 30%; and using a grouting method to pour modified phosphogypsum slurry with a fluidity greater than or equal to 140 mm and a water consumption of 35-55% into the aggregate.The present application first uses a specific phosphogypsum ceramsite and a specific phosphogypsum slurry to rapidly and efficiently construct a road stable base by using a grouting method, and the road stable base after construction is well formed, stable in quality, and has the characteristics of rapid opening to traffic.The road stable base has the characteristics of no mixing and same-cycle life, is convenient for full recycling and reuse, and has very important significance for the large-scale and high-quality application of industrial solid waste phosphogypsum.

Description

Technical Field

[0001] This invention relates to the fields of comprehensive utilization of bulk solid waste and road technology, and in particular to a rapid grouting and molding method for road stabilization base course made of phosphogypsum. Background Technology

[0002] The majority of road base courses are semi-rigid, with the vast majority being cement-stabilized crushed stone base courses. This results in a huge consumption of natural aggregates and cementitious materials, and the extraction of natural aggregates is becoming increasingly difficult.

[0003] Wuhan University of Technology, in its patent application CN113123187A, provides a method for constructing a pebbly-interlocked pavement base course using waste concrete. Specifically, the pebbles form an interlocking skeleton, providing load-bearing capacity for the pavement base structure. A high-flow-state filler (self-compacting fine aggregate concrete or mortar) fills the voids between the pebbles, and after hardening, it stabilizes the pebbly skeleton, reducing horizontal displacement and creep of the pebbly-interlocked pavement base material. The formed pebbly skeleton effectively prevents the continuous propagation and development of cracks throughout the base course, thus improving the inherent cracking defects of traditional semi-rigid base courses and effectively balancing good mechanical and durability properties. From a raw material perspective, this method not only proposes a method for recycling waste concrete, but also ensures that the pavement base course does not rely on natural aggregates. However, the high-flow-state filler (self-compacting fine aggregate concrete or mortar) used in this method requires a large amount of fine aggregate and cement. This fine aggregate consists of manufactured sand or fine stone and recycled fine aggregate generated during the preparation of pebbles from waste concrete (within 10mm), which limits the further development of this pebbly-interlocked pavement base course. Furthermore, before filling with high-flow self-compacting fine aggregate concrete or mortar, it is necessary to stack the single-graded waste concrete aggregate and spread it evenly using pavers and graders; after filling with high-flow self-compacting fine aggregate concrete or mortar, it is also necessary to use a vibratory roller for compaction; this results in low road construction efficiency and long time to open to traffic, further limiting the further development of this type of aggregate interlocking pavement base course.

[0004] Therefore, this invention is proposed. Summary of the Invention

[0005] Gypsum, a component of industrial solid waste, is also a raw material for the production of inorganic cementitious materials, and its abundant reserves have led to increasing attention as a substitute for cement, natural gypsum, or natural aggregates. This invention provides a rapid grouting method for forming a road stabilized base course using phosphogypsum. For the first time, specific phosphogypsum ceramsite and a specific phosphogypsum slurry are used in a rapid and efficient grouting method for road stabilized base course construction (i.e., grouting molding). This not only solves the problem of excessive reliance on natural aggregates and cement in traditional semi-rigid base courses, but also produces a well-formed, stable road stabilized base course that allows for rapid traffic opening. Because the resulting road stabilized base course has a homogeneous structure, it has a uniform lifespan, facilitating full recycling and reuse. This is of great significance for the large-scale, high-quality application of industrial solid waste phosphogypsum.

[0006] Specifically, in a first aspect, the present invention provides a method for preparing a road stabilization base course using a phosphogypsum grouting method, comprising:

[0007] Paving with phosphogypsum ceramsite with a softening coefficient of ≥85% forms a road stabilized base aggregate skeleton with a skeleton porosity of ≥30%.

[0008] A modified phosphogypsum slurry with a flowability greater than or equal to 140 mm and a water content of 35-55% was injected into the skeleton using a grouting method.

[0009] After grouting, the surface is leveled and smoothed to facilitate the construction of the upper layer.

[0010] According to the preparation method of the road stabilization base layer formed by phosphogypsum grouting provided by the present invention, the modified phosphogypsum slurry is made by mixing high-temperature modified phosphogypsum with a fineness of 80-200 mesh as the main raw material with water; in order to achieve a balance between the pouring fluidity and water consumption of the modified phosphogypsum slurry, the present invention preferably uses high-temperature modified phosphogypsum with a fineness of 150-200 mesh as the main raw material.

[0011] When adding water and mixing, after adding water for the first time until the mixture is uniform, continue mixing at a stirring speed of ≥1200 rpm until the water content of the resulting slurry is 35-55% and the fluidity is greater than or equal to 140 mm.

[0012] Preferably, at the end of the first water addition, the amount of water added is 15-18% of the mixture.

[0013] The time from mixing with water to grouting and molding of the high-temperature modified phosphogypsum does not exceed 45 minutes.

[0014] In this invention, the water content of the modified phosphogypsum slurry needs to be strictly controlled. If too little water is added, the hydration reaction cannot be fully activated to stimulate its gelling activity and necessary working performance. If too much water is added, the modified phosphogypsum will be formed by crystallization, resulting in a significant decrease in structural density, reduced application performance, reduced strength, and failure to meet the softening coefficient requirements.

[0015] Generally, the mixing time for modified phosphogypsum grout is greater than or equal to 3 minutes.

[0016] According to the preparation method of the phosphogypsum grouting method for road stabilization base provided by the present invention, the high-temperature modified phosphogypsum has a pH value ≥7.0, a hemihydrate gypsum content ≥65%, soluble phosphorus ≤0.2%, soluble fluorine ≤0.1%, a 2-hour compressive strength ≥5.0MPa, and a flexural strength ≥2.0MPa.

[0017] According to the preparation method of the road stabilization base layer formed by phosphogypsum grouting provided by the present invention, the high-temperature modified phosphogypsum is obtained by calcining industrial solid waste phosphogypsum at a temperature above 120°C.

[0018] When the soluble phosphorus and fluorine in the industrial solid waste phosphogypsum exceed the standard, the calcination temperature is above 400℃; when the heavy metals in the industrial solid waste phosphogypsum exceed the standard, the calcination temperature is above 800℃.

[0019] Preferably, the calcination temperature of 800°C or above involves mixing the phosphogypsum premix with high-temperature ceramsite, using the residual heat of the ceramsite for combustion, and then continuing the mixing and calcination process. The coarse aggregate of the ceramsite is then separated to obtain a residue with a ceramsite powder content of ≤30wt%, which is then further processed to obtain the final product.

[0020] According to the preparation method of the road stabilization base layer formed by phosphogypsum grouting provided by the present invention, the temperature of the high-temperature modified phosphogypsum during water mixing is less than or equal to 45°C.

[0021] During mixing, the temperature of the high-temperature modified phosphogypsum is crucial to the ease of mixing and the achievement of grouting fluidity. If water is added during mixing, the temperature of the high-temperature modified phosphogypsum will be too high. Even if the grouting method is achieved, the fluidity will not meet the standard, which will significantly reduce the density of the road stabilized base course and affect its application.

[0022] According to the preparation method of the phosphogypsum grouting method for road stabilization base provided by the present invention, the calcination time is greater than or equal to 48 hours.

[0023] Because high-temperature modified phosphogypsum with a fineness of 80-200 mesh is used, the aging time after calcination plays an important role in ensuring smooth mixing and achieving a flowability of over 140 mm under the specified water content. The longer the aging time, the more stable the high-temperature modified phosphogypsum, and the higher the homogeneity of the mixed slurry.

[0024] According to the preparation method of the modified phosphogypsum grouting method for road stabilization base provided by the present invention, the modified phosphogypsum slurry further includes additives;

[0025] The content of the additive is 0.1% to 0.3%;

[0026] The admixtures include one or more of the following: retarder, water-reducing agent, and waterproofing agent.

[0027] According to the preparation method of the phosphogypsum grouting method for road stabilization base provided by the present invention, the particle shape coefficient of the phosphogypsum ceramsite is less than or equal to 2.0.

[0028] The particle shape coefficient of the phosphogypsum ceramsite is very important for the filling of the slurry; the smaller the particle shape coefficient, the better the overall structure.

[0029] According to the preparation method of the phosphogypsum grouting method for road stabilization base provided by the present invention, the compressive strength of the phosphogypsum ceramsite is greater than or equal to 5.0 MPa, the particle size is 5-31.5 mm, and single-graded is preferred;

[0030] Preferably, the phosphogypsum ceramsite is made by mixing and grinding gypsum powder, gypsum retarder and water as the main raw materials, and then immediately adding water to granulate to obtain aggregate blanks. The aggregate blanks are then air-dried, allowed to stand and harden.

[0031] Alternatively, the phosphogypsum ceramsite is prepared by using gypsum powder, gypsum retarder and water as the main raw materials, and then mixing them at a high speed of 1200 rpm for no less than 3 minutes before adding water for granulation to obtain aggregate blanks. The aggregate blanks are then air-dried, allowed to stand, and hardened.

[0032] Secondly, this invention also provides a road stabilized base course prepared by the phosphogypsum grouting method described above. The road stabilized base course is simple to construct, requiring no large-scale mixing system or site on-site. Construction only requires layout, formwork erection, granulation, and grouting. The process is simple and easy to operate. Furthermore, the 2-hour compressive strength of the formed road stabilized base course reaches over 90% of its 24-hour compressive strength, with a softening coefficient ≥85% and a 24-hour compressive strength ≥3.5 MPa.

[0033] This invention provides a rapid grouting method for forming a road stabilized base course using phosphogypsum and its preparation. The method involves spreading phosphogypsum ceramsite with a softening coefficient greater than or equal to 85% to form a road stabilized base course aggregate with a porosity greater than or equal to 30%. A modified phosphogypsum slurry with a flowability greater than or equal to 140 mm and a water content less than or equal to 55% is then injected into the aggregate using a grouting method. This invention achieves, for the first time, rapid and efficient construction of a road stabilized base course using specific phosphogypsum skeleton materials and specific phosphogypsum slurry through grouting. Compared to existing road stabilized base courses, the advantages of this invention include:

[0034] (1) The full application of phosphogypsum in road base courses solves the problem of large-scale and high-quality comprehensive utilization of phosphogypsum solid waste.

[0035] (2) After the phosphogypsum is modified, it can be used as both a cementing material and a binder. This solves the environmental pollution problem and also addresses the issues of the multi-faceted nature of traditional road stabilization base materials, short lifespan, and difficulty in secondary utilization.

[0036] (3) It solves the problem of high demand for mixing equipment and site and large investment in supporting infrastructure in the application of traditional road stabilized base materials, making road base construction more convenient.

[0037] (4) It solves the problem of the traditional road base material's need for natural resources such as mineral aggregates and cement.

[0038] (5) Complete solid waste resource utilization and closed-loop recycling.

[0039] (6) Construction is faster, molding is faster, early strength is higher, and curing is not required. Opening to traffic earlier can greatly shorten the effective construction period of the project. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0041] Figures 1-5 This is a schematic diagram of different time points from the start of grouting to the end of grouting in the rapid grouting molding of the phosphogypsum road stabilization base provided in Embodiment 1C of the present invention.

[0042] Figure 6 This is a schematic diagram of the internal structure of the phosphogypsum rapid grouting and molding road stabilization base layer after molding, according to Embodiment 1C of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0044] The following is combined Figures 1-6 This invention describes a rapid grouting and molding method for road stabilization base course using phosphogypsum and its preparation method.

[0045] The gypsum powder in this invention contains 80% building gypsum, 8% anhydrous gypsum, and 4% dihydrate gypsum, with a particle size of 80–200 μm.

[0046] The minerals in this invention are derived from industrial tailings, waste residues, etc., and their main mineral components include: SiO2 53-70%, Al2O3 12-26% and CaO 3-5%; the remaining components are mainly NaO2, FeO, MgO and Fe2O3, accounting for 8-24%.

[0047] Example 1A High-Temperature Modified Phosphogypsum

[0048] A method for preparing high-temperature modified phosphogypsum, the process of which is as follows:

[0049] (1) Crush and sieve the phosphogypsum to break up the small clumps in the original phosphogypsum.

[0050] (2) The powder with small agglomerates is pretreated by water washing;

[0051] (3) After the phosphogypsum is washed, it is naturally dehydrated and dried until no obvious water seeps out. Then it is sent to a calcination system at 120℃ for calcination for ≥15min.

[0052] (4) The calcined phosphogypsum is passed through a ball mill to make it fine to 150-200 mesh;

[0053] (5) The ball-milled modified phosphogypsum was transported to an aging chamber for aging treatment for ≥48 hours. The obtained high-temperature modified phosphogypsum was tested, and the test results were as follows: hemihydrate gypsum >70%, dihydrate gypsum 8%, anhydrous gypsum 1%, pH value 7, and fineness 150-200 mesh. Furthermore, the high-temperature modified phosphogypsum had soluble phosphorus ≤0.2%, soluble fluorine ≤0.1%, 2-hour compressive strength ≥5.0 MPa, and flexural strength ≥2.0 MPa.

[0054] Example 2A High-Temperature Modified Phosphogypsum

[0055] A method for preparing high-temperature modified phosphogypsum, the process of which is as follows:

[0056] (1) Crush and sieve the phosphogypsum to break up the small clumps in the original phosphogypsum.

[0057] (2) The powder with small agglomerates is pretreated by water washing;

[0058] (3) After the phosphogypsum is washed, it is naturally dehydrated and dried until no obvious water seeps out. Then it is sent to a calcination system at 240℃ for calcination for ≥15min.

[0059] (4) The calcined phosphogypsum is passed through a ball mill to achieve a fineness of 150-200 mesh;

[0060] (5) The ball-milled modified phosphogypsum was transported to an aging chamber for aging treatment for ≥48 hours. The obtained high-temperature modified phosphogypsum was tested, and the test results were as follows: the modified phosphogypsum contained 86% hemihydrate gypsum, 2% dihydrate gypsum, and 8% anhydrous gypsum, with a pH value of 7.2, a fineness of 150-200 mesh, and the soluble phosphorus content ≤0.2%, soluble fluorine content ≤0.1%, 2-hour compressive strength ≥5.0 MPa, and flexural strength ≥2.0 MPa.

[0061] Example 3A High-Temperature Modified Phosphogypsum

[0062] A method for preparing high-temperature modified phosphogypsum, the process of which is as follows:

[0063] (1) Phosphogypsum is pretreated by heating to obtain a phosphogypsum premix with a temperature of 70°C, a free water content of 10% and an organic matter content of 15%, wherein the mass content of calcium sulfate dihydrate in the phosphogypsum premix is ​​60%.

[0064] Mix 65% waste soil, 30% sludge, 5% phosphogypsum and the remaining minerals according to the specified ratio, age, granulate, and calcine at high temperature (calcination temperature is 1100℃).

[0065] (2) Add the phosphogypsum premix from step (1) to the ceramsite obtained after high-temperature calcination in step (1). At this time, ensure that the temperature of the ceramsite is above 800°C when it is added. After combustion using the residual heat of the ceramsite, continue mixing and calcination, and then separate the coarse aggregate of ceramsite with an average particle size of more than 2.36 mm, so that the content of ceramsite powder in the obtained residue is 5%. Further grind, cool and age the obtained residue for 96 hours to obtain the high-temperature modified phosphogypsum. When grinding, adjust the mesh size of the ball mill filter so that the fineness of the modified phosphogypsum after grinding reaches the standard requirement of 150-200 mesh.

[0066] The SiO2 content of this ceramsite is 65%, and the density of the ceramsite is 450 kg / m³. 3 The average particle size is 30 mm, the porosity is 45%, and the mass ratio of phosphogypsum premix to the ceramsite is 1:1. Without external heating, the two continue to burn for 10 seconds. The mixing and calcination time is controlled at 10 minutes. After a brief rise, the material temperature gradually reaches 400-600℃.

[0067] The high-temperature modified phosphogypsum was tested, and the results showed that it contained 82% β-type gypsum and 5% silicate; the pH value of the high-temperature modified phosphogypsum was above 7 and the fineness reached 150-200 mesh; and the strength of the high-temperature modified phosphogypsum reached grade 3.0.

[0068] Example 1B: Phosphogypsum Ceramsite

[0069] A method for preparing phosphogypsum ceramsite involves mixing and grinding 100 parts of gypsum powder, 0.03 parts of gypsum retarder (sodium citrate), 0.03 parts of gypsum water-reducing agent (polycarboxylate water-reducing agent), 0.05 parts of gypsum waterproofing agent (methyl silicone resin), and 10 parts of water as raw materials. Immediately after grinding, 17 parts of water are added for granulation to obtain aggregate blanks, which are then air-dried, allowed to stand, and hardened to obtain the final product.

[0070] Example 2B: Phosphogypsum Ceramsite

[0071] A method for preparing phosphogypsum ceramsite involves using 100 parts gypsum powder, 0.03 parts gypsum retarder (sodium polyphosphate), 0.03 parts gypsum water-reducing agent (polycarboxylate water-reducing agent), 0.05 parts gypsum waterproofing agent (calcium stearate), and 12 parts water as raw materials. The mixture is then subjected to high-speed forced mixing at a speed of 1200 rpm for at least 3 minutes, followed by the addition of 17 parts water for granulation to obtain aggregate blanks. These blanks are then air-dried, allowed to stand, and hardened to obtain the final product.

[0072] The phosphogypsum ceramsite prepared in Examples 1B-2B was tested using the following methods:

[0073] Cylinder compressive strength: GB / T 17431.2-2010.

[0074] Softening coefficient: determined in accordance with relevant national standards.

[0075] The test results are as follows:

[0076]

[0077] Example 1C

[0078] A method for preparing a rapid grouting and molding road stabilization base course using phosphogypsum includes:

[0079] (1) Inspection and cleaning before the construction of the base layer

[0080] (2) Measurement, layout and model erection

[0081] (3) Aggregate: The phosphogypsum ceramsite of Example 1B is laid to form a road stabilized base aggregate skeleton with a skeleton porosity of 35%;

[0082] (4) The high-temperature modified phosphogypsum prepared in Example 1A, along with a retarder, water-reducing agent, waterproofing agent, and water, were mixed in the following proportions. After the first addition of water until the mixture was homogeneous, it was further mixed at a stirring speed of 1200 rpm until the water content of the resulting slurry was 55% and the fluidity was 140 mm, thus obtaining the modified phosphogypsum slurry. At the end of the first water addition, the water volume was 17% of the mixture, and the mixing time was 3 minutes. The amounts of the retarder, water-reducing agent, and waterproofing agent added were all 1%.

[0083] (5) The modified phosphogypsum slurry after mixing is transported by external pressure pump to the aggregate skeleton of the road stabilized base course for grouting. Grouting is carried out by moving from one side of the road base course to the other until the slurry is full, with continuous grouting on both sides, and then gradually filling the remaining area. The grouting process in the laboratory pilot stage is as follows: Figures 1-5 As shown. Figure 6 This is a diagram of its internal structure after molding.

[0084] (6) Smooth the surface and allow it to cure until the strength reaches ≥2.5MPa, meeting the specifications.

[0085] (7) Acceptance and handover, opening to traffic or construction of the underlying layer.

[0086] Example 2C

[0087] It is basically the same as Example 1C, except that the phosphogypsum ceramsite in Example 1B is replaced with the phosphogypsum ceramsite in Example 2B.

[0088] Example 3C

[0089] It is basically the same as Example 1C, except that the high-temperature modified phosphogypsum prepared in Example 1A is replaced with the high-temperature modified phosphogypsum prepared in Example 2A.

[0090] Example 4C

[0091] It is basically the same as Example 1C, except that the high-temperature modified phosphogypsum prepared in Example 1A is replaced with the high-temperature modified phosphogypsum prepared in Example 3A.

[0092] Example 5C

[0093] It is basically the same as Example 1C, except that the water content in the modified phosphogypsum slurry is increased but reduced to 50%.

[0094] Example 6C

[0095] It is basically the same as Example 1C, except that the water content in the modified phosphogypsum slurry is increased but reduced to 45%.

[0096] Example 7C

[0097] It is basically the same as Example 1C, except that the water content in the modified phosphogypsum slurry is increased but reduced to 40%.

[0098]

[0099] Comparative Example 1

[0100] It is basically the same as Example 1C, except that the mixing time is adjusted so that its fluidity is 100 mm.

[0101]

[0102] Comparative Example 2

[0103] It is basically the same as Example 1C, except that the phosphogypsum ceramsite is replaced with phosphogypsum ceramsite with a softening coefficient of 70% and a similar size.

[0104] Example 1C 1.67 5.5 Dense, without honeycomb or pitted surface Comparative Example 2 1.52 2.0 Dense, without honeycomb or pitted surface

[0105] Comparative Example 3

[0106] It is basically the same as Example 1C, except that the porosity of the aggregate in the road stabilization base course is controlled at 20% during paving.

[0107] Example 1C 1.67 5.5 Dense, without honeycomb or pitted surface Comparative Example 3 1.60 3.4 Slow infusion rate

[0108] Comparative Example 4

[0109] It is basically the same as Example 1C, except that the water content of the modified phosphogypsum slurry is reduced to 30%.

[0110] Comparative Example 5

[0111] It is basically the same as Example 1C, except that the water content of the modified phosphogypsum slurry is increased to 65%.

[0112]

[0113]

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a road stabilization base course using phosphogypsum grouting, characterized in that, include: The paving softening coefficient is greater than or equal to 85% of phosphogypsum ceramsite, the compressive strength of the phosphogypsum ceramsite is greater than or equal to 5.0 MPa, the particle size is 5~31.5 mm, and the gradation is single-graded, forming a road stabilized base aggregate skeleton with a skeleton porosity greater than or equal to 30%. A modified phosphogypsum slurry with a flowability greater than or equal to 140 mm and a water content of 35-55% was injected into the skeleton using a grouting method. The modified phosphogypsum slurry is made by mixing high-temperature modified phosphogypsum with a fineness of 80-200 mesh as the main raw material with water. When adding water, after the first addition of water and mixing until uniform, the mixture is stirred at a speed of ≥1200 rpm until the water content of the resulting slurry is 35-55% and the fluidity is greater than or equal to 140 mm. When the first addition of water is completed, the amount of water added is 15-18% of the mixture. The time from adding water to mixing the high-temperature modified phosphogypsum to casting and molding does not exceed 45 minutes.

2. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 1, characterized in that, The pH value of the high-temperature modified phosphogypsum is ≥ 7.0, and the mass content of hemihydrate gypsum is ≥65%, soluble phosphorus ≤0.2%, soluble fluorine ≤0.1%, 2-hour compressive strength ≥5.0MPa, and flexural strength ≥2.0MPa.

3. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 1 or 2, characterized in that, The high-temperature modified phosphogypsum is obtained by calcining industrial solid waste phosphogypsum at a temperature above 120°C. When the soluble phosphorus and fluorine in the industrial solid waste phosphogypsum exceed the standard, the calcination temperature is above 400℃; when the heavy metals in the industrial solid waste phosphogypsum exceed the standard, the calcination temperature is above 800℃.

4. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 3, characterized in that, The calcination temperature of 800℃ or above involves mixing phosphogypsum premix with high-temperature ceramsite, using the residual heat of the ceramsite for combustion, and then continuing the mixing and calcination process. The coarse aggregate of the ceramsite is then separated to obtain a residue with a ceramsite powder content of ≤30wt%, which is then further processed to obtain the final product.

5. The method for preparing a road stabilization base course using phosphogypsum grouting according to any one of claims 1, 2, or 4, characterized in that, When adding water and mixing, the temperature of the high-temperature modified phosphogypsum is less than or equal to 45°C.

6. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 3, characterized in that, When adding water and mixing, the temperature of the high-temperature modified phosphogypsum is less than or equal to 45°C.

7. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 3, characterized in that, The calcination process results in an aging time of 48 hours or more.

8. The method for preparing a road stabilization base course using phosphogypsum grouting according to any one of claims 1, 2, 4, 6-7, characterized in that, The modified phosphogypsum slurry also includes additives; The content of the additive is 0.1~0.3%; The admixtures include one or more of the following: retarder, water-reducing agent, and waterproofing agent.

9. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 3, characterized in that, The modified phosphogypsum slurry also includes additives; The content of the additive is 0.1~0.3%; The admixtures include one or more of the following: retarder, water-reducing agent, and waterproofing agent.

10. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 5, characterized in that, The modified phosphogypsum slurry also includes additives; The content of the additive is 0.1~0.3%; The admixture includes one or more of the following: retarder, water-reducing agent, and waterproofing agent.

11. The method for preparing a road stabilized base course using phosphogypsum grouting according to any one of claims 1, 2, 4, 6-7, 9-10, characterized in that, The particle shape coefficient of the phosphogypsum ceramsite is less than or equal to 2.

0.

12. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 3, characterized in that, The particle shape coefficient of the phosphogypsum ceramsite is less than or equal to 2.

0.

13. The method for preparing a road stabilization base course using the phosphogypsum grouting method according to claim 5, characterized in that, The particle shape coefficient of the phosphogypsum ceramsite is less than or equal to 2.

0.

14. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 8, characterized in that, The particle shape coefficient of the phosphogypsum ceramsite is less than or equal to 2.

0.

15. The method for preparing a road stabilization base course using phosphogypsum grouting according to any one of claims 1, 2, 4, 6-7, 9-10, and 12-14, characterized in that, The phosphogypsum ceramsite is made by mixing gypsum powder, gypsum retarder and water as the main raw materials, grinding them together, and then immediately adding water to granulate them to obtain aggregate blanks. The aggregate blanks are then air-dried, left to stand, and hardened. Alternatively, the phosphogypsum ceramsite is prepared by using gypsum powder, gypsum retarder and water as the main raw materials, and then mixing them at a high speed of 1200 rpm for no less than 3 minutes before adding water for granulation to obtain aggregate blanks. The aggregate blanks are then air-dried, allowed to stand, and hardened.

16. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 3, characterized in that, The phosphogypsum ceramsite is made by mixing gypsum powder, gypsum retarder and water as the main raw materials, grinding them together, and then immediately adding water to granulate them to obtain aggregate blanks. The aggregate blanks are then air-dried, left to stand, and hardened. Alternatively, the phosphogypsum ceramsite is prepared by using gypsum powder, gypsum retarder and water as the main raw materials, and then mixing them at a high speed of 1200 rpm for no less than 3 minutes before adding water for granulation to obtain aggregate blanks. The aggregate blanks are then air-dried, allowed to stand, and hardened.

17. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 5, characterized in that, The phosphogypsum ceramsite is made by mixing gypsum powder, gypsum retarder and water as the main raw materials, grinding them together, and then immediately adding water to granulate them to obtain aggregate blanks. The aggregate blanks are then air-dried, left to stand, and hardened. Alternatively, the phosphogypsum ceramsite is prepared by using gypsum powder, gypsum retarder and water as the main raw materials, and then mixing them at a high speed of 1200 rpm for no less than 3 minutes before adding water for granulation to obtain aggregate blanks. The aggregate blanks are then air-dried, allowed to stand, and hardened.

18. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 8, characterized in that, The phosphogypsum ceramsite is made by mixing gypsum powder, gypsum retarder and water as the main raw materials, grinding them together, and then immediately adding water to granulate them to obtain aggregate blanks. The aggregate blanks are then air-dried, left to stand, and hardened. Alternatively, the phosphogypsum ceramsite is prepared by using gypsum powder, gypsum retarder and water as the main raw materials, and then mixing them at a high speed of 1200 rpm for no less than 3 minutes before adding water for granulation to obtain aggregate blanks. The aggregate blanks are then air-dried, allowed to stand, and hardened.

19. The method for preparing a road stabilization base course using phosphogypsum grouting according to claim 11, characterized in that, The phosphogypsum ceramsite is made by mixing gypsum powder, gypsum retarder and water as the main raw materials, grinding them together, and then immediately adding water to granulate them to obtain aggregate blanks. The aggregate blanks are then air-dried, left to stand, and hardened. Alternatively, the phosphogypsum ceramsite is prepared by using gypsum powder, gypsum retarder and water as the main raw materials, and then mixing them at a high speed of 1200 rpm for no less than 3 minutes before adding water for granulation to obtain aggregate blanks. The aggregate blanks are then air-dried, allowed to stand, and hardened.

20. The road stabilized base course prepared by the method of phosphogypsum grouting molding of any one of claims 1 to 19, characterized in that, The road stabilized base course has a 2-hour compressive strength of more than 90% of its 24-hour compressive strength, a softening coefficient of ≥85%, and a 24-hour compressive strength of ≥3.5MPa.

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