Phosphogypsum stabilizer for phosphogypsum roads and method for laying phosphogypsum roads

Abstract

The application provides a phosphogypsum stabilizer for phosphogypsum road and a laying method of the phosphogypsum road, and belongs to the technical field of solid waste resource utilization. The phosphogypsum stabilizer for phosphogypsum road comprises a first component, a second component and a third component which are independently packaged respectively; wherein the first component comprises 350-490 mass parts of blast furnace slag powder, 50-200 mass parts of slag powder, 50-200 mass parts of fly ash, 10-50 mass parts of silica ash, 1-3 mass parts of calcium lignin sulfonate, 1-3 mass parts of hydroxypropyl methyl cellulose and 1-3 mass parts of sodium dodecyl benzene sulfonate; the second component comprises 40-80 mass parts of desulfurization gypsum and 40-80 mass parts of titanium gypsum; and the third component comprises 30-60 mass parts of carbide slag powder and 5-20 mass parts of anhydrous sodium sulfate. The phosphogypsum stabilizer has excellent road performance, low cost, simple preparation and convenient application, and can be used to stabilize and solidify phosphogypsum by comprehensively utilizing various solid wastes without using cement.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, and more specifically, to a phosphogypsum stabilizer for phosphogypsum roads and a method for laying phosphogypsum roads. Background Technology

[0002] Phosphogypsum is an acidic solid waste produced during the wet-process production of phosphoric acid, with its main component being calcium sulfate dihydrate (CaSO4·2H2O). Approximately 4.5 to 5.5 tons of phosphogypsum are generated for every ton of phosphoric acid produced (calculated as P2O5), resulting in global annual emissions in the hundreds of millions of tons. The large-scale stockpiling of phosphogypsum not only occupies land, but also contains soluble phosphorus (P2O5) and fluorides (F2O5). - Trace amounts of heavy metals and acidic substances pose a serious threat to groundwater and soil after being leached by rainwater.

[0003] Using phosphogypsum in road engineering, especially as a road raw material, is one of the most effective ways to utilize its resources on a large scale. However, the acidity, low strength, poor water stability, and presence of harmful impurities in phosphogypsum necessitate stabilization and solidification treatment before it can be used.

[0004] Currently, the stabilization technology for phosphogypsum mainly uses cement and / or curing agents as stabilizers, neutralizing the acidity of phosphogypsum and providing cementitious properties through ordinary silicate cement. For example, Chinese patent CN104909695A discloses a method for preparing a hydraulic road base material made of phosphogypsum, which uses the acid-base neutralization reaction between calcium oxide in cement and phosphogypsum to achieve the harmless treatment of phosphogypsum, and uses a curing agent (containing various organic polymer materials and various nanomaterials) to improve the performance of the road subgrade. However, this method has some intractable drawbacks: such curing is costly, especially the curing agent, which is expensive and has poor economic benefits; the soluble phosphorus and phosphorus in phosphogypsum can seriously delay cement hydration, resulting in low early strength and difficulty in meeting construction schedule requirements; it is prone to drying shrinkage cracks, and its long-term durability is questionable.

[0005] Currently, phosphogypsum is mainly produced in China's heavy industrial bases, which also contain numerous heavy industrial enterprises that generate large amounts of solid waste requiring treatment and disposal. Achieving the co-utilization of phosphogypsum and other solid wastes within these heavy industrial bases is crucial for improving the overall utilization rate of solid waste and reducing its utilization costs.

[0006] It should be noted that the information in the background section above is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a phosphogypsum stabilizer and a method for paving phosphogypsum roads. This method can stabilize and solidify phosphogypsum by comprehensively utilizing various solid wastes without the need for cement, thereby realizing the resource utilization of phosphogypsum.

[0008] According to a first aspect of the present invention, a phosphogypsum stabilizer for phosphogypsum roads is provided, comprising a first component, a second component, and a third component, each packaged separately.

[0009] The first component comprises 350-490 parts by weight of blast furnace slag powder, 50-200 parts by weight of slag powder, 50-200 parts by weight of fly ash, 10-50 parts by weight of silica fume, 1-3 parts by weight of calcium lignosulfonate, 1-3 parts by weight of hydroxypropyl methylcellulose, and 1-3 parts by weight of sodium dodecylbenzenesulfonate.

[0010] The second component comprises 40-80 parts by weight of desulfurized gypsum and 40-80 parts by weight of titanium gypsum;

[0011] The third component includes 30-60 parts by weight of carbide slag powder and 5-20 parts by weight of sodium sulfate.

[0012] According to one embodiment of the present invention, the first component comprises 390-460 parts by weight of blast furnace slag powder, 80-150 parts by weight of slag powder, 80-150 parts by weight of fly ash, 20-45 parts by weight of silica fume, 1.5-2.5 parts by weight of calcium lignosulfonate, 1.5-2.5 parts by weight of hydroxypropyl methylcellulose, and 1.5-2.5 parts by weight of sodium dodecylbenzenesulfonate.

[0013] According to one embodiment of the present invention, the blast furnace slag powder is of grade S95, with a specific surface area of ​​not less than 420 m² / kg and a moisture content of not more than 1%.

[0014] According to one embodiment of the present invention, the specific surface area of ​​the slag powder is not less than 420 m². 2 / kg, moisture content not greater than 1%.

[0015] According to one embodiment of the present invention, the fly ash is Class II fly ash produced by a coal-fired power plant, and the 28-day strength activity index of the fly ash is not less than 75%.

[0016] According to one embodiment of the present invention, the silica fume has a silica content of not less than 85%; the specific surface area of ​​the silica fume is not less than 12 m². 2 / g.

[0017] According to one embodiment of the present invention, the dry basis content of calcium sulfate dihydrate in desulfurized gypsum is not less than 80%, and the dry basis content of calcium sulfate hemihydrate is not greater than 10%.

[0018] The dry basis content of calcium sulfate dihydrate in titanium gypsum is not less than 85%;

[0019] The calcium hydroxide content of the calcium carbide slag powder is not less than 80%;

[0020] The sodium sulfate content of sodium sulfate is not less than 99%.

[0021] According to one embodiment of the present invention, the first component consists of 420 parts by weight of blast furnace slag powder, 110 parts by weight of slag powder, 100 parts by weight of fly ash, 30 parts by weight of silica fume, 2 parts by weight of calcium lignosulfonate, 2 parts by weight of hydroxypropyl methylcellulose, and 2 parts by weight of sodium dodecylbenzenesulfonate.

[0022] The second component consists of 60 parts by mass of desulfurized gypsum and 60 parts by mass of titanium gypsum;

[0023] The third component consists of 45 parts by weight of carbide slag powder and 12 parts by weight of sodium sulfate.

[0024] According to one embodiment of the present invention, the soluble phosphorus content in the phosphogypsum to be stabilized does not exceed 1% by mass, and the soluble fluorine content does not exceed 0.5% by mass.

[0025] According to a second aspect of the present invention, a method for paving phosphogypsum roads is provided, employing a road mixing method, comprising:

[0026] Step S1: Determine the dosage and optimal moisture content of the phosphogypsum stabilizer based on the phosphogypsum to be stabilized.

[0027] Step S2: Lay the phosphogypsum to be stabilized on the roadbed and level it. Spray water onto the surface of the phosphogypsum according to the optimum moisture content.

[0028] Step S3: Thoroughly mix the first, second, and third components of the phosphogypsum stabilizer to form the stabilizer to be used; spread the stabilizer to be used on the leveled surface of the phosphogypsum to be stabilized.

[0029] Step S4: Use a road mixer to mix the phosphogypsum to be stabilized and the stabilizer to be used evenly. Mix the road mixer 2-4 times, and then use a grader to level the surface.

[0030] Step S5: Use a bulldozer or loader to compact the phosphogypsum base 3-4 times, then use a double-drum roller to compact it 3-4 times, then use a single-drum vibratory roller to compact it 4-6 times, and finally use a rubber-tired roller to compact it 1-2 times.

[0031] Step S6: Sprinkle water and cover the compacted phosphogypsum road for maintenance for more than 14 days.

[0032] According to one embodiment of the present invention, the amount of the phosphogypsum stabilizer is 8% to 15% of the mass of the phosphogypsum to be stabilized.

[0033] According to one embodiment of the present invention, the phosphogypsum to be stabilized is aged phosphogypsum or modified phosphogypsum, the pH value of the phosphogypsum is 5-8, and the water content is not more than 25%.

[0034] According to a third aspect of the present invention, a method for paving phosphogypsum roads is provided, employing a plant-mixing construction process, comprising:

[0035] Step S1: Determine the dosage and optimal moisture content of the phosphogypsum stabilizer based on the phosphogypsum to be stabilized.

[0036] Step S2: Use a soil stabilization mixer to mix the phosphogypsum to be stabilized, the phosphogypsum stabilizer, and the amount of water added according to the optimum moisture content, and stir until uniform.

[0037] Step S3: Transport vehicles are used to transport the mixed stabilized phosphogypsum mixture to the construction site;

[0038] Step S4: Use a paver to spread the stabilized phosphogypsum mixture onto the leveled subgrade or underlying layer surface;

[0039] Step S5, then use a double-drum roller to compact 3-4 times, then use a single-drum vibratory roller to compact 4-6 times, and finally use a rubber-tired roller to compact 1-2 times.

[0040] Step S6: Sprinkle water and cover the compacted phosphogypsum road for maintenance for more than 14 days.

[0041] According to one embodiment of the present invention, the amount of the phosphogypsum stabilizer is 8% to 15% of the mass of the phosphogypsum to be stabilized.

[0042] According to one embodiment of the present invention, the phosphogypsum to be stabilized is aged phosphogypsum or modified phosphogypsum, the pH value of the phosphogypsum is 5-8, and the water content is not more than 25%.

[0043] First, the main components of the phosphogypsum stabilizer of this invention are all bulk industrial solid wastes, eliminating the need for cement production. This "waste-to-waste" approach results in extremely low costs, achieving resource recycling and yielding significant environmental and economic benefits. In particular, in certain heavy industrial base areas, phosphogypsum stabilizers can be produced at low cost using solid wastes generated within these areas, such as blast furnace slag (solid waste from steel plants), furnace slag (solid waste from steel plants), fly ash (solid waste from thermal power plants), silica fume (solid waste from ferroalloy plants or silicon smelting plants), desulfurization gypsum (solid waste from thermal power plants), titanium gypsum (solid waste from titanium dioxide plants), and carbide slag (solid waste from polyethylene or polyvinyl chloride chemical plants). This enables the on-site resource-based synergistic utilization of various solid wastes. The phosphogypsum stabilizer produced from solid wastes in this region can stabilize and solidify the phosphogypsum (solid waste from phosphoric acid plants) generated in the heavy industrial base area, allowing the stabilized and solidified phosphogypsum to be used for paving phosphogypsum roads and meeting some of the road needs within the heavy industrial base area. Therefore, the phosphogypsum stabilizer and phosphogypsum road paving method of the present invention can realize the local resource utilization of various solid wastes in some areas, reducing the high costs caused by cross-regional allocation of solid wastes.

[0044] Secondly, this invention constructs a ternary synergistic activation system of "alkali activation (carbide slag powder) - sulfate activation (sodium sulfate + desulfurized gypsum + titanium gypsum) - pozzolanic effect (blast furnace slag powder / furnace slag powder / fly ash / silica fume)". When this phosphogypsum stabilizer is mixed with the phosphogypsum to be stabilized, the carbide slag powder provides a continuous high-alkali environment to neutralize the acidity of the phosphogypsum; sodium sulfate provides early-stage sulfate ions, rapidly generating the ettringite framework to improve the early strength of the phosphogypsum path; desulfurized gypsum and titanium gypsum provide mid-to-late-stage sulfate ions, making the ettringite growth more continuous and stable; titanium gypsum has a smaller particle size and a greater dissolution rate than desulfurized gypsum, quickly taking over from sodium sulfate to provide sufficient sulfate ions for the phosphogypsum path, ensuring the continuous development of the phosphogypsum path strength; desulfurized gypsum can guarantee a sustained supply of sulfate ions in the phosphogypsum path. During the paving process of the phosphogypsum road of this invention, various industrial solid wastes can be fully activated in an alkaline environment to generate a large amount of CSH gel, CASH gel, and ettringite, which interweave into an extremely dense network structure. This not only improves the early strength of the phosphogypsum road but also ensures the continuous development of its strength and achieves the coating of impurities in the phosphogypsum.

[0045] Titanium gypsum, being highly acidic and containing numerous impurities, is typically avoided as a substandard raw material in solid waste utilization. This invention reveals that impurities such as iron and aluminum it contains may participate in reactions under alkaline conditions to regulate the hydration process. Furthermore, the difference in dissolution rates between titanium gypsum and desulfurized gypsum provides a gradual and continuous supply of sulfate ions, avoiding premature setting or insufficient late-stage reaction problems that may occur with single-gypsum systems, thus achieving optimized control of the hydration process. Moreover, during the compaction of phosphogypsum roads, titanium gypsum, with its smaller particle size, can fill the voids in the phosphogypsum, improving the compaction rate of the phosphogypsum road.

[0046] Furthermore, the strongly alkaline environment provided by the phosphogypsum stabilizer of this invention can convert soluble phosphorus and phosphorus into stable hydroxyapatite and calcium fluoride precipitates; simultaneously, the dense network of hydration products provides excellent physical encapsulation and adsorption of impurities. This ensures that phosphogypsum roads have low leaching toxicity and improves environmental safety.

[0047] Furthermore, the phosphogypsum stabilizer of this invention enables phosphogypsum roads to possess excellent performance. On one hand, the abundant hydration products generated by the synergistic effect of the various components give phosphogypsum roads high early strength and high later strength. On the other hand, the phosphogypsum stabilizer of this invention can improve the crack resistance of phosphogypsum roads, with an effect no less than that of commonly used stabilizing materials such as cement. In the phosphogypsum stabilizer of this invention, hydroxypropyl methylcellulose has a water-retaining effect, which can reduce the evaporation of water in the phosphogypsum road, thereby effectively reducing the plastic shrinkage cracks in the phosphogypsum road. Calcium lignosulfonate has a strong dispersing effect, which can ensure the uniform hydration of the phosphogypsum stabilizer and reduce the risk of local stress concentration. Sodium dodecylbenzenesulfonate can reduce the surface tension of water, trapping introduced air during the mixing process and forming a large number of tiny, independent, and uniformly distributed closed bubbles; these tiny bubbles can accommodate the water that expands during freezing, releasing internal pressure, thereby improving the ability of phosphogypsum roads to resist freeze-thaw cycles. At the same time, the heat release during the hydration process of the phosphogypsum stabilizer of this invention is milder than that of cement, reducing the risk of temperature cracks in phosphogypsum roads. On the other hand, the phosphogypsum stabilizer of the present invention can improve the water stability and durability of phosphogypsum roads. The phosphogypsum stabilizer of the present invention can form a dense gel structure, which can effectively reduce the risk of water intrusion into phosphogypsum roads.

[0048] Furthermore, in this invention, the first, second, and third components of the phosphogypsum stabilizer are individually packaged during storage, achieving physical separation. Before using the phosphogypsum stabilizer to cure the phosphogypsum, the first, second, and third components are thoroughly mixed, and then thoroughly mixed with the phosphogypsum to be stabilized. The independent packaging of the first, second, and third components fundamentally eliminates the pre-hydration reaction caused by moisture absorption during storage and transportation, significantly extending the product's shelf life. This not only facilitates the large-scale application and formulation of the phosphogypsum stabilizer but also ensures the performance of phosphogypsum roads during long-term construction projects.

[0049] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0050] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0051] Figure 1 The results show the unconfined compressive strength of each cured phosphogypsum sample.

[0052] Figure 2 The softening coefficient test results are for each solidified phosphogypsum sample.

[0053] Figure 3 The results show the freeze-thaw resistance coefficient of each solidified phosphogypsum sample.

[0054] Figure 4 The splitting tensile strength test results are for each cured phosphogypsum sample. Detailed Implementation

[0055] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that the invention will be thorough and complete, and the concept of the exemplary embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted. Furthermore, the drawings are merely illustrative of the invention and are not necessarily drawn to scale.

[0056] In this invention, unless otherwise specified, the moisture content of a material refers to the mass content of free water contained in the material.

[0057] This invention provides a phosphogypsum stabilizer for phosphogypsum roads, comprising a first component, a second component, and a third component, each packaged separately. The first component comprises 350-490 parts by weight of blast furnace slag powder, 50-200 parts by weight of slag powder, 50-200 parts by weight of fly ash, 10-50 parts by weight of silica fume, 1-3 parts by weight of calcium lignosulfonate, 1-3 parts by weight of hydroxypropyl methylcellulose, and 1-3 parts by weight of sodium dodecylbenzenesulfonate. The second component comprises 40-80 parts by weight of desulfurized gypsum and 40-80 parts by weight of titanium gypsum. The third component comprises 30-60 parts by weight of calcium carbide slag powder and 5-20 parts by weight of sodium sulfate.

[0058] The first, second, and third components of the phosphogypsum stabilizer provided by this invention are packaged separately. In use, the first, second, and third components are first thoroughly mixed to form the phosphogypsum stabilizer to be used. Then, the phosphogypsum stabilizer to be used is thoroughly mixed with the phosphogypsum to be stabilized, water is added, and the mixture is compacted and cured to achieve stable solidification of the phosphogypsum to be stabilized. After stabilization and solidification using the phosphogypsum stabilizer provided by this invention, phosphogypsum roads can be formed, meeting the engineering requirements for roads. Thus, the phosphogypsum stabilizer of this invention can stabilize and solidify phosphogypsum by utilizing various solid wastes, eliminating the need for cement, thus replacing high-cost cement and achieving resource utilization of various solid wastes.

[0059] In one embodiment of the present invention, the first component, the second component, and the third component are each packaged in a coated polypropylene woven bag.

[0060] In one embodiment of the present invention, the specific surface area of ​​the blast furnace slag powder is not less than 420 m² / kg. This ensures the rapid release of the active components of the blast furnace slag powder, improving the early strength of phosphogypsum roads.

[0061] In one embodiment of the present invention, the blast furnace slag powder is of grade S95, with a specific surface area of ​​not less than 420 m² / kg and a moisture content of not more than 1%.

[0062] In one embodiment of the present invention, the mass coefficient of the blast furnace slag powder is not less than 1.7, and the alkalinity coefficient is not less than 1.1. This ensures the quality of the active components of the blast furnace slag powder and guarantees the density of the gel network formed during the solidification of phosphogypsum.

[0063] The calculation method for the quality coefficient K1 of blast furnace slag powder is: K1=[W(CaO)+W(MgO)+W(Al2O3)] / [W(SiO2)+W(MnO)+W(TiO2)].

[0064] The method for calculating the basicity coefficient K2 of blast furnace slag powder is as follows:

[0065] K2=[W(CaO)+W(MgO)] / [W(SiO2)+W(Al2O3)].

[0066] W(CaO) is the calcium oxide content in blast furnace slag powder determined by chemical composition analysis.

[0067] W(MgO) represents the magnesium oxide content in blast furnace slag powder determined by chemical composition analysis.

[0068] W(Al2O3) represents the alumina content in blast furnace slag powder determined by chemical composition analysis.

[0069] W(SiO2) represents the silica content in blast furnace slag powder determined by chemical composition analysis.

[0070] W(MnO) represents the manganese oxide content in blast furnace slag powder determined by chemical composition analysis.

[0071] W(TiO2) represents the titanium oxide content in blast furnace slag powder determined by chemical composition analysis.

[0072] In one embodiment of the present invention, the moisture content of the blast furnace slag powder does not exceed 1%.

[0073] In one embodiment of the present invention, the specific surface area of ​​the slag powder is not less than 420 m². 2 / kg, moisture content not greater than 1%.

[0074] In one embodiment of the present invention, the loss on ignition of the slag powder is no more than 10%, the content of free calcium oxide is no more than 5%, the fineness (residue on a 45μm square-hole sieve) is no more than 25%, and the basicity coefficient is no less than 1. This ensures that the slag powder has sufficient fine particles to participate in the reaction and improves the gradation.

[0075] In one embodiment of the present invention, the fly ash is bituminous fly ash, with a loss on ignition of no more than 5%, a fineness (residue on a 45μm square-hole sieve) of no more than 25%, and a sulfur trioxide content of no more than 3%. In one example, the fly ash is Class II fly ash produced by a coal-fired power plant, and the 28-day strength activity index of the fly ash is no less than 75%.

[0076] In one embodiment of the present invention, the silica content of the silica fume is not less than 85%; the specific surface area of ​​the silica fume is not less than 12 m². 2 / g.

[0077] In one example, the silica fume is Grade 85 silica fume produced from the smelting of ferrosilicon alloys. This allows for a reduction in the quality requirements of the silica fume, thereby lowering the cost of phosphogypsum stabilizers, while ensuring that the phosphogypsum road surface meets the required standards.

[0078] In one embodiment of the present invention, the dry basis content of calcium sulfate dihydrate in the desulfurized gypsum is not less than 80%, and the dry basis content of calcium sulfate hemihydrate is not greater than 10%.

[0079] In one example, the dry basis content of calcium sulfate dihydrate in desulfurized gypsum is not less than 90%.

[0080] In one embodiment of this disclosure, the dry basis content of calcium sulfate dihydrate in titanium gypsum is not less than 85%.

[0081] In one embodiment of the present invention, the free acid content of titanium gypsum does not exceed 0.8% to avoid excessive acidity and impurities in titanium gypsum affecting the effect of phosphogypsum stabilizer.

[0082] In one embodiment of the present invention, the calcium hydroxide content of the carbide slag powder is not less than 80% to ensure that the carbide slag powder provides sufficient alkaline active substances.

[0083] In one embodiment of this disclosure, the sodium sulfate content of sodium sulfate is not less than 99%.

[0084] In one embodiment of the present invention, the first component comprises 390-460 parts by weight of blast furnace slag powder, 80-150 parts by weight of slag powder, 80-150 parts by weight of fly ash, 20-45 parts by weight of silica fume, 1.5-2.5 parts by weight of calcium lignosulfonate, 1.5-2.5 parts by weight of hydroxypropyl methylcellulose, and 1.5-2.5 parts by weight of sodium dodecylbenzenesulfonate. Thus, this phosphogypsum stabilizer provides road construction phosphogypsum with stabilization and curing properties comparable to or better than cement in terms of strength, crack resistance, water resistance, and frost resistance, completely replacing cement and thereby improving the synergistic utilization of various solid wastes and reducing the paving cost of phosphogypsum roads.

[0085] In one example, the first component consists of 420 parts by weight of blast furnace slag powder, 110 parts by weight of slag powder, 100 parts by weight of fly ash, 30 parts by weight of silica fume, 2 parts by weight of calcium lignosulfonate, 2 parts by weight of hydroxypropyl methylcellulose, and 2 parts by weight of sodium dodecylbenzenesulfonate.

[0086] The second component consists of 60 parts by mass of desulfurized gypsum and 60 parts by mass of titanium gypsum;

[0087] The third component consists of 45 parts by weight of carbide slag powder and 12 parts by weight of sodium sulfate.

[0088] In one embodiment of the present invention, the soluble phosphorus content in the phosphogypsum to be stabilized does not exceed 1% by mass, and the soluble fluorine content does not exceed 0.5% by mass. This reduces the environmental risk of phosphogypsum roads. Of course, in practical engineering applications, the phosphogypsum stabilizer of the present invention can also be used to stabilize and solidify phosphogypsum with excessive soluble phosphorus by adding calcium carbide slag powder or lime powder.

[0089] This invention also provides a method for laying phosphogypsum roads, specifically a method for laying phosphogypsum roads using the road mixing method. The method for laying phosphogypsum roads includes:

[0090] Step S1: Determine the dosage of phosphogypsum stabilizer and the optimal moisture content based on the phosphogypsum to be stabilized.

[0091] Step S2: Lay the phosphogypsum to be stabilized on the roadbed and level it; spray water onto the surface of the phosphogypsum according to the optimum moisture content;

[0092] Step S3: Thoroughly mix the first, second, and third components of the phosphogypsum stabilizer to form the stabilizer to be used; spread the stabilizer to be used on the leveled surface of the phosphogypsum to be stabilized.

[0093] Step S4: Use a road mixer to mix the phosphogypsum to be stabilized and the stabilizer to be used evenly. Mix the road mixer 2-4 times, and then use a grader to level the surface.

[0094] Step S5: Use a bulldozer or loader to compact the phosphogypsum base 3-4 times, then use a double-drum roller to compact it 3-4 times, then use a single-drum vibratory roller to compact it 4-6 times, and finally use a rubber-tired roller to compact it 1-2 times.

[0095] Step S6: Sprinkle water and cover the compacted phosphogypsum road for maintenance for more than 14 days.

[0096] In the construction of the phosphogypsum road of the present invention, a phosphogypsum layer to be stabilized is first laid, then water is sprayed onto the road surface via a spraying method, and then the phosphogypsum stabilizer to be used is spread on the phosphogypsum layer. During the road mixing process, the phosphogypsum layer, the stabilizer layer, and the sprayed water are mixed evenly to form a mixture layer. After compaction and curing of this mixture layer, a phosphogypsum road can be obtained. The phosphogypsum stabilizer of the present invention has a slightly wider dosage range when stabilizing and solidifying phosphogypsum, thus the road mixing method can be used to improve road construction efficiency and reduce road construction costs.

[0097] In one example of the present invention, the amount of the phosphogypsum stabilizer is 8% to 15% of the mass of the phosphogypsum to be stabilized. In practical applications, the specific amount of phosphogypsum stabilizer can be determined through laboratory pre-tests.

[0098] In one example of the present invention, the phosphogypsum to be stabilized is aged phosphogypsum with a moisture content of no more than 25%. When the moisture content of the phosphogypsum is too high, the phosphogypsum can be dried to remove water.

[0099] In one embodiment of the present invention, when using a road mixer for road mixing, the mixing depth is not less than the thickness of the phosphogypsum layer.

[0100] This invention also provides another method for laying phosphogypsum roads, specifically a method for laying phosphogypsum roads using a plant-mixing method. This method for laying phosphogypsum roads includes:

[0101] Step S1: Determine the dosage of phosphogypsum stabilizer and the optimal moisture content based on the phosphogypsum to be stabilized.

[0102] Step S2: Use a soil stabilization mixer to mix the phosphogypsum to be stabilized, the phosphogypsum stabilizer, and the amount of water added according to the optimum moisture content, and stir until uniform.

[0103] Step S3: Transport vehicles are used to transport the mixed stabilized phosphogypsum mixture to the construction site;

[0104] Step S4: Use a paver to spread the stabilized phosphogypsum mixture onto the leveled roadbed surface;

[0105] Step S5, then use a double-drum roller to compact 3-4 times, then use a single-drum vibratory roller to compact 4-6 times, and finally use a rubber-tired roller to compact 1-2 times.

[0106] Step S6: Sprinkle water and cover the compacted phosphogypsum road for maintenance for more than 14 days.

[0107] In one example of the present invention, the amount of the phosphogypsum stabilizer is 8% to 15% of the mass of the phosphogypsum to be stabilized. In practical applications, the specific amount of phosphogypsum stabilizer can be determined through laboratory pre-tests.

[0108] In one example of the present invention, the phosphogypsum to be stabilized is aged phosphogypsum with a moisture content of no more than 25%. When the moisture content of the phosphogypsum is too high, the phosphogypsum can be dried to remove water.

[0109] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto. Unless otherwise specified, all parts refer to parts by weight.

[0110] Preparation of phosphogypsum stabilizer

[0111] Example 1

[0112] Preparation of phosphogypsum stabilizer 1.

[0113] The first component of phosphogypsum stabilizer 1 comprises 42 parts by weight of blast furnace slag powder, 11 parts by weight of blast furnace slag powder, 10 parts by weight of fly ash, 3 parts by weight of silica fume, 0.2 parts by weight of calcium lignosulfonate, 0.2 parts by weight of hydroxypropyl methylcellulose, and 0.2 parts by weight of sodium dodecylbenzene sulfonate; the second component comprises 6 parts by weight of desulfurized gypsum and 6 parts by weight of titanium gypsum; the third component comprises 4.5 parts by weight of calcium carbide slag powder and 1.2 parts by weight of sodium sulfate. The first component, after premixing, is packaged in coated polypropylene woven bags. The second component, after premixing, is packaged in coated polypropylene woven bags. The third component, after premixing, is packaged in coated polypropylene woven bags.

[0114] Among them, the specific surface area of ​​blast furnace slag powder is 460m². 2 / kg, with a mass coefficient of 1.72, an alkalinity coefficient of 1.18, and a moisture content of 0.9%.

[0115] The loss on ignition of the slag powder was 8.7%, the content of free calcium oxide was 2.9%, the fineness (residue on a 45μm square hole sieve) was 23%, and the alkalinity coefficient was 1.06.

[0116] The fly ash is bituminous fly ash, with a loss on ignition of 4.8%, a fineness (residue on a 45μm square-hole sieve) of 19%, and a sulfur trioxide content of 2.1%.

[0117] Silica fume is grade 85 silica fume produced during the smelting of ferrosilicon alloys.

[0118] The desulfurized gypsum contains 94% calcium sulfate dihydrate, is white with a slight yellow tint, has a pH of 6.7, and a water content of 7%.

[0119] The titanium gypsum is light yellow in color, contains 0.7% free acid, has a pH value of 4.2, and a water content of 11.7%.

[0120] The calcium hydroxide content of the calcium carbide slag powder is 84%, and the water content is 11%.

[0121] Example 2

[0122] Preparation of phosphogypsum stabilizer 2.

[0123] The first component of phosphogypsum stabilizer 2 comprises 45 parts by weight of blast furnace slag powder, 10 parts by weight of blast furnace slag powder, 12 parts by weight of fly ash, 2.5 parts by weight of silica fume, 0.15 parts by weight of calcium lignosulfonate, 0.25 parts by weight of hydroxypropyl methylcellulose, and 0.2 parts by weight of sodium dodecylbenzene sulfonate; the second component comprises 5 parts by weight of desulfurized gypsum and 7 parts by weight of titanium gypsum; the third component comprises 5 parts by weight of calcium carbide slag powder and 1 part by weight of sodium sulfate. The first component, after premixing, is packaged in coated polypropylene woven bags. The second component, after premixing, is packaged in coated polypropylene woven bags. The third component, after premixing, is packaged in coated polypropylene woven bags.

[0124] The components used in phosphogypsum stabilizer 2 are obtained from the same batch as the components of phosphogypsum stabilizer 1.

[0125] Example 3

[0126] Preparation of phosphogypsum stabilizer 3.

[0127] The first component of phosphogypsum stabilizer 3 comprises 39 parts by weight of blast furnace slag powder, 15 parts by weight of blast furnace slag powder, 8 parts by weight of fly ash, 4.5 parts by weight of silica fume, 0.25 parts by weight of calcium lignosulfonate, 0.15 parts by weight of hydroxypropyl methylcellulose, and 0.25 parts by weight of sodium dodecylbenzene sulfonate; the second component comprises 7 parts by weight of desulfurized gypsum and 5 parts by weight of titanium gypsum; the third component comprises 4 parts by weight of calcium carbide slag powder and 1.5 parts by weight of sodium sulfate. The first component, after premixing, is packaged in coated polypropylene woven bags. The second component, after premixing, is packaged in coated polypropylene woven bags. The third component, after premixing, is packaged in coated polypropylene woven bags.

[0128] The components used in phosphogypsum stabilizer 3 are obtained from the same batch as the components of phosphogypsum stabilizer 1.

[0129] Example 4

[0130] Preparation of phosphogypsum stabilizer 4.

[0131] The first component of phosphogypsum stabilizer 4 comprises 46 parts by weight of blast furnace slag powder, 8 parts by weight of blast furnace slag powder, 15 parts by weight of fly ash, 2 parts by weight of silica fume, 0.1 parts by weight of calcium lignosulfonate, 0.2 parts by weight of hydroxypropyl methylcellulose, and 0.3 parts by weight of sodium dodecylbenzene sulfonate; the second component comprises 4 parts by weight of desulfurized gypsum and 7 parts by weight of titanium gypsum; the third component comprises 5.5 parts by weight of calcium carbide slag powder and 1.5 parts by weight of sodium sulfate. The first component, after premixing, is packaged in coated polypropylene woven bags. The second component, after premixing, is packaged in coated polypropylene woven bags. The third component, after premixing, is packaged in coated polypropylene woven bags.

[0132] The components used in phosphogypsum stabilizer 4 are obtained from the same batch as the components of phosphogypsum stabilizer 1.

[0133] Example 5

[0134] Preparation of phosphogypsum stabilizer 5.

[0135] The first component of phosphogypsum stabilizer 5 comprises 42 parts by weight of blast furnace slag powder, 11 parts by weight of blast furnace slag powder, 15 parts by weight of fly ash, 2 parts by weight of silica fume, 0.2 parts by weight of calcium lignosulfonate, 0.5 parts by weight of hydroxypropyl methylcellulose, and 0.1 parts by weight of sodium dodecylbenzene sulfonate; the second component comprises 5 parts by weight of desulfurized gypsum and 8 parts by weight of titanium gypsum; the third component comprises 4.5 parts by weight of calcium carbide slag powder and 1.2 parts by weight of sodium sulfate. The first component, after premixing, is packaged in coated polypropylene woven bags. The second component, after premixing, is packaged in coated polypropylene woven bags. The third component, after premixing, is packaged in coated polypropylene woven bags.

[0136] The components used in phosphogypsum stabilizer 5 are obtained from the same batch as the components of phosphogypsum stabilizer 1.

[0137] Comparative Example 1

[0138] Preparation of phosphogypsum stabilizer 6.

[0139] The first component of phosphogypsum stabilizer 6 comprises 42 parts by weight of blast furnace slag powder, 11 parts by weight of blast furnace slag powder, 10 parts by weight of fly ash, 3 parts by weight of silica fume, and 0.2 parts by weight of calcium lignosulfonate, without the addition of hydroxypropyl methylcellulose and sodium dodecylbenzene sulfonate; the second component comprises 6 parts by weight of desulfurized gypsum and 6 parts by weight of titanium gypsum; the third component comprises 4.5 parts by weight of calcium carbide slag powder and 1.2 parts by weight of sodium sulfate. The first component, after premixing, is packaged in coated polypropylene woven bags. The second component, after premixing, is packaged in coated polypropylene woven bags. The third component, after premixing, is packaged in coated polypropylene woven bags.

[0140] The components used in phosphogypsum stabilizer 6 are obtained from the same batch as the components of phosphogypsum stabilizer 1.

[0141] Comparative Example 2

[0142] Preparation of phosphogypsum stabilizer 7.

[0143] The first component of phosphogypsum stabilizer 7 comprises 42 parts by weight of blast furnace slag powder, 11 parts by weight of blast furnace slag powder, 10 parts by weight of fly ash, 3 parts by weight of silica fume, 0.2 parts by weight of calcium lignosulfonate, and 0.2 parts by weight of hydroxypropyl methylcellulose, without the addition of sodium dodecylbenzene sulfonate; the second component comprises 13 parts by weight of desulfurized gypsum, without the addition of titanium gypsum; the third component comprises 4.5 parts by weight of calcium carbide slag powder and 1.2 parts by weight of sodium sulfate. The first component, after premixing, is packaged in coated polypropylene woven bags. The second component, after premixing, is packaged in coated polypropylene woven bags. The third component, after premixing, is packaged in coated polypropylene woven bags.

[0144] The components used in phosphogypsum stabilizer 7 are obtained from the same batch as the components of phosphogypsum stabilizer 1.

[0145] Comparative Example 3

[0146] Preparation of phosphogypsum stabilizer 8.

[0147] The components and dosages of phosphogypsum stabilizer 8 are the same as those of phosphogypsum stabilizer 1. The only difference is that the first, second, and third components of phosphogypsum stabilizer 1 are packaged separately in coated polypropylene woven bags; while the components of phosphogypsum stabilizer 8 are packaged separately in coated polypropylene woven bags after being mixed evenly.

[0148] The performance of phosphogypsum stabilizers 1 to 8, ordinary silicate cement (as phosphogypsum stabilizer 9), and ordinary silicate cement + lime (mass ratio of 5:1, as phosphogypsum stabilizer 10) was tested.

[0149] Among them, phosphogypsum stabilizers 1 to phosphogypsum stabilizers 8 are temporarily stored in an environment with a temperature not exceeding 30°C and a humidity not exceeding 25% after being packaged in coated polypropylene woven bags, and the time of starting use is no more than 15 days away from the time of being packaged.

[0150] In the testing, the phosphogypsum came from a phosphoric acid plant with an initial moisture content of 18%, a pH of 3.2, a soluble phosphorus content (calculated as phosphorus pentoxide) of 0.85%, and a soluble fluoride content (calculated as fluoride ions) of 0.32%. After being spread out and weathered, the moisture content of the phosphogypsum decreased to 4.5%. This weathered phosphogypsum was used as the test phosphogypsum to be stabilized.

[0151] Sample preparation

[0152] The phosphogypsum to be stabilized was cured using phosphogypsum stabilizer 1 to obtain cured phosphogypsum sample 1. The specific preparation process is as follows:

[0153] 1) Through experiments, the optimal moisture content of the mixture was determined when using phosphogypsum stabilizer 1 to solidify the phosphogypsum to be stabilized.

[0154] 2) The first, second and third components of phosphogypsum stabilizer 1 are thoroughly mixed to form phosphogypsum stabilizer 1 to be used.

[0155] 3) Thoroughly mix the phosphogypsum stabilizer 1 to be used with the phosphogypsum to be stabilized, and add water during the mixing process according to the optimum moisture content to obtain the mixture to be compacted. The mass of the phosphogypsum stabilizer 1 to be used is 10% of the mass of the phosphogypsum to be stabilized.

[0156] 4) The mixture to be compacted was compacted and shaped using a press static pressing method, and after standard curing, a cured phosphogypsum sample 1 was obtained.

[0157] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 2 was used to cure the phosphogypsum to be stabilized, thus obtaining cured phosphogypsum sample 2.

[0158] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 3 was used to cure the phosphogypsum to be stabilized, thus obtaining cured phosphogypsum sample 3.

[0159] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 4 was used to cure the phosphogypsum to be stabilized, thus obtaining cured phosphogypsum sample 4.

[0160] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 5 was used to cure the phosphogypsum to be stabilized, thus obtaining cured phosphogypsum sample 5.

[0161] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 6 was used to cure the phosphogypsum to be stabilized, thus obtaining cured phosphogypsum sample 6.

[0162] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 7 was used to cure the phosphogypsum to be stabilized, thus obtaining cured phosphogypsum sample 7.

[0163] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 8 was used to cure the phosphogypsum to be stabilized, and cured phosphogypsum sample 8 was obtained.

[0164] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 9 was used to cure the phosphogypsum to be stabilized, thus obtaining cured phosphogypsum sample 9.

[0165] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 10 was used to cure the phosphogypsum to be stabilized, thereby obtaining cured phosphogypsum sample 10.

[0166] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 1 was used to cure the phosphogypsum to be stabilized, resulting in cured phosphogypsum sample 11. The mass of phosphogypsum stabilizer 1 used was 6% of the mass of the phosphogypsum to be stabilized.

[0167] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 1 was used to cure the phosphogypsum to be stabilized, resulting in cured phosphogypsum sample 12. The mass of phosphogypsum stabilizer 1 used was 8% of the mass of the phosphogypsum to be stabilized.

[0168] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 1 was used to cure the phosphogypsum to be stabilized, resulting in cured phosphogypsum sample 13. The mass of phosphogypsum stabilizer 1 used was 12% of the mass of the phosphogypsum to be stabilized.

[0169] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 1 was used to cure the phosphogypsum to be stabilized, resulting in cured phosphogypsum sample 14. The mass of phosphogypsum stabilizer 1 used was 15% of the mass of the phosphogypsum to be stabilized.

[0170] A portion of phosphogypsum stabilizer 1 was placed in an accelerated aging chamber for aging without opening the film-coated polypropylene woven bag. The environment inside the accelerated aging chamber was 45℃ and 75% relative humidity. After 15 days of accelerated aging, the unopened phosphogypsum stabilizer 1 was designated as phosphogypsum stabilizer 11; after 30 days of accelerated aging, the unopened phosphogypsum stabilizer 1 was designated as phosphogypsum stabilizer 12.

[0171] A portion of the phosphogypsum stabilizer 8 was placed in an accelerated aging chamber for aging without opening the film-coated polypropylene woven bag. The phosphogypsum stabilizer 8 without opening the packaging was used as phosphogypsum stabilizer 13 after 15 days of accelerated aging; the phosphogypsum stabilizer 8 without opening the packaging was used as phosphogypsum stabilizer 14 after 30 days of accelerated aging.

[0172] The caking state of phosphogypsum stabilizers 11 to 14 was examined. The results showed that phosphogypsum stabilizer 11 remained in powder form; the second component of phosphogypsum stabilizer 12 showed slight caking, while the remaining components remained essentially in powder form; phosphogypsum stabilizer 13 showed mild caking with low caking strength; and phosphogypsum stabilizer 14 showed large caking lumps, some of which were quite hard and difficult to break.

[0173] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 11 was used to cure the phosphogypsum to be stabilized, resulting in cured phosphogypsum sample 15. The mass of the phosphogypsum stabilizer 11 used was 10% of the mass of the phosphogypsum to be stabilized.

[0174] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 12 was used to cure the phosphogypsum to be stabilized, resulting in cured phosphogypsum sample 16. The mass of the phosphogypsum stabilizer 12 used was 10% of the mass of the phosphogypsum to be stabilized.

[0175] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 13 was used to cure the phosphogypsum to be stabilized, resulting in cured phosphogypsum sample 17. The mass of phosphogypsum stabilizer 13 used was 10% of the mass of the phosphogypsum to be stabilized.

[0176] Following the preparation method of cured phosphogypsum sample 1, phosphogypsum stabilizer 14 was used to cure the phosphogypsum to be stabilized, resulting in cured phosphogypsum sample 18. The mass of phosphogypsum stabilizer 14 used was 10% of the mass of the phosphogypsum to be stabilized.

[0177] The unconfined compressive strength of cured phosphogypsum specimens 1 to 18 was tested. The test results are available in [link to test results]. Figure 1 See Table 1.

[0178] Table 1: Unconfined compressive strength of cured phosphogypsum specimens

[0179]

[0180] according to Figure 1 As shown in Table 1, the 7-day unconfined compressive strength of cured phosphogypsum samples 1-8, 13, and 14 is superior to that of cured phosphogypsum samples 9 and 10. This indicates that the phosphogypsum stabilizer provided by this invention can improve the early strength of phosphogypsum roads compared to conventional phosphogypsum stabilizers such as cement or cement / lime. The 28-day and 90-day unconfined compressive strengths of each cured phosphogypsum sample also demonstrate that the phosphogypsum stabilizer provided by this invention allows for the continuous development of the strength of phosphogypsum roads, and the long-term strength of phosphogypsum roads can reach a level comparable to or superior to that of cement-modified phosphogypsum roads, thus meeting the engineering requirements for phosphogypsum roads in terms of strength.

[0181] Comparing the unconfined compressive strengths of cured phosphogypsum samples 15 to 18, it can be seen that the first, second, and third components of the phosphogypsum stabilizer of the present invention, when packaged separately, can maintain a considerable shelf life under high temperature and high humidity conditions, with a relatively slow rate of performance degradation. It can be understood that under conventional cool, dry storage conditions, this phosphogypsum stabilizer can maintain high activity for a long time. In contrast, phosphogypsum stabilizer 8 (with the first, second, and third components pre-mixed) shows a more significant performance decline under high temperature and high humidity conditions. This indicates that the separate packaging of the first, second, and third components of the phosphogypsum stabilizer of the present invention is beneficial for extending the shelf life of the phosphogypsum stabilizer.

[0182] The softening coefficients of cured phosphogypsum samples 1 to 18 were tested. The test results are available in the [link to test results]. Figure 2 .according to Figure 2It can be seen that the 7-day softening coefficients of cured phosphogypsum samples 1-8 and 13-16 are all superior to or comparable to those of cured phosphogypsum samples 9 / 10. The 28-day and 90-day softening coefficients of cured phosphogypsum samples 1-8, 13, and 14 are also superior to or comparable to those of cured phosphogypsum samples 9 / 10. Furthermore, the softening coefficients of cured phosphogypsum samples 1-14 all show a good development trend. This indicates that the phosphogypsum stabilizer of the present invention provides stable phosphogypsum road surfaces with good water resistance, meeting engineering requirements.

[0183] Comparing the softening coefficients of cured phosphogypsum samples 15 to 18, it can be seen that the softening coefficient of the phosphogypsum samples stabilized and cured by phosphogypsum stabilizer 8 decreased significantly, indicating that they underwent significant deterioration during accelerated aging and storage.

[0184] The frost resistance coefficients of cured phosphogypsum samples 1 to 17 were tested. The test results are available in the [link to test results]. Figure 3 .according to Figure 3 It can be seen that the 28-day freeze-thaw resistance coefficients of cured phosphogypsum samples 1 to 15 are roughly equivalent, all not less than 85%; the 90-day freeze-thaw resistance coefficients of cured phosphogypsum samples 1 to 14 are roughly equivalent, all not less than 93%. The freeze-thaw resistance coefficients of cured phosphogypsum samples 1, 2, 6, 7, 9, 13, and 14 are all not less than 96%. This indicates that the phosphogypsum road stabilized and cured by the phosphogypsum stabilizer provided by this invention can have high freeze-thaw resistance and can meet engineering requirements. Comparing the freeze-thaw resistance coefficients of cured phosphogypsum samples 15 to 17, it can be seen that the freeze-thaw resistance coefficient of the phosphogypsum samples stabilized and cured by phosphogypsum stabilizer 8 decreases significantly, indicating that it has undergone significant deterioration during accelerated aging storage.

[0185] The splitting tensile strength of cured phosphogypsum specimens 1 to 14 was tested. The test results are available in [link to test results]. Figure 4 And Table 2.

[0186] Table 2: Splitting strength of cured phosphogypsum samples

[0187]

[0188] according to Figure 4As shown in Table 2, the 28-day splitting tensile strength of cured phosphogypsum samples 1, 2, 3, 6, 13, and 14 is better than or comparable to that of cured phosphogypsum samples 9 / 10. Similarly, the 90-day splitting tensile strength of cured phosphogypsum samples 1, 3, 4, 6, 7, 13, and 14 is better than or comparable to that of cured phosphogypsum samples 9 / 10. Furthermore, the splitting tensile strength of cured phosphogypsum samples 1 through 14 all show a good development trend. This indicates that the phosphogypsum stabilizer of the present invention provides stable phosphogypsum road surfaces with good crack resistance, meeting engineering requirements.

[0189] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention described herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not invented herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the appended claims.

Claims

1. A phosphogypsum stabilizer for phosphogypsum roads, characterized in that, It includes three separately packaged components: the first component, the second component, and the third component. The first component comprises 350-490 parts by weight of blast furnace slag powder, 50-200 parts by weight of slag powder, 50-200 parts by weight of fly ash, 10-50 parts by weight of silica fume, 1-3 parts by weight of calcium lignosulfonate, 1-3 parts by weight of hydroxypropyl methylcellulose, and 1-3 parts by weight of sodium dodecylbenzenesulfonate. The second component comprises 40-80 parts by weight of desulfurized gypsum and 40-80 parts by weight of titanium gypsum; The third component includes 30-60 parts by weight of carbide slag powder and 5-20 parts by weight of sodium sulfate. The dry basis content of calcium sulfate dihydrate in the titanium gypsum is not less than 85%. The phosphogypsum to be stabilized contains no more than 1% soluble phosphorus and no more than 0.5% soluble fluorine by mass. The phosphogypsum to be stabilized is aged phosphogypsum or modified phosphogypsum with a pH value of 5-8 and a water content of no more than 25%. The amount of phosphogypsum stabilizer used is 8%-15% of the mass of the phosphogypsum to be stabilized.

2. The phosphogypsum stabilizer for phosphogypsum roads according to claim 1, characterized in that, The first component comprises 390-460 parts by weight of blast furnace slag powder, 80-150 parts by weight of slag powder, 80-150 parts by weight of fly ash, 20-45 parts by weight of silica fume, 1.5-2.5 parts by weight of calcium lignosulfonate, 1.5-2.5 parts by weight of hydroxypropyl methylcellulose, and 1.5-2.5 parts by weight of sodium dodecylbenzenesulfonate.

3. The phosphogypsum stabilizer for phosphogypsum roads according to claim 1, characterized in that, The specific surface area of ​​the blast furnace slag powder is not less than 420 m² / kg, and the moisture content is not greater than 1%.

4. The phosphogypsum stabilizer for phosphogypsum roads according to claim 1, characterized in that, The specific surface area of ​​the slag powder is not less than 420 m². 2 / kg, moisture content not greater than 1%.

5. The phosphogypsum stabilizer for phosphogypsum roads according to claim 1, characterized in that, The fly ash is Class II fly ash produced by a coal-fired power plant, and the 28-day strength activity index of the fly ash is not less than 75%.

6. The phosphogypsum stabilizer for phosphogypsum roads according to claim 1, characterized in that, The silica content of the silica fume is not less than 85%; the specific surface area of ​​the silica fume is not less than 12 m². 2 / g.

7. The phosphogypsum stabilizer for phosphogypsum roads according to claim 1, characterized in that, The dry basis content of calcium sulfate dihydrate in desulfurized gypsum is not less than 80%, and the dry basis content of calcium sulfate hemihydrate is not greater than 10%. The calcium hydroxide content of the calcium carbide slag powder is not less than 80%; The sodium sulfate content of sodium sulfate is not less than 99%.

8. The phosphogypsum stabilizer for phosphogypsum roads according to claim 1, characterized in that, The first component consists of 420 parts by weight of blast furnace slag powder, 110 parts by weight of slag powder, 100 parts by weight of fly ash, 30 parts by weight of silica fume, 2 parts by weight of calcium lignosulfonate, 2 parts by weight of hydroxypropyl methylcellulose, and 2 parts by weight of sodium dodecylbenzenesulfonate. The second component consists of 60 parts by mass of desulfurized gypsum and 60 parts by mass of titanium gypsum; The third component consists of 45 parts by weight of carbide slag powder and 12 parts by weight of sodium sulfate.

9. A method for paving phosphogypsum roads, employing a road-mixing construction process, characterized in that, include: Step S1: Determine the amount and optimal moisture content of the phosphogypsum stabilizer according to any one of claims 1 to 8, based on the phosphogypsum to be stabilized. Step S2: Lay the phosphogypsum to be stabilized on the roadbed and level it. Spray water onto the surface of the phosphogypsum according to the optimum moisture content. Step S3: Thoroughly mix the first, second, and third components of the phosphogypsum stabilizer to form the stabilizer to be used; spread the stabilizer to be used on the leveled surface of the phosphogypsum to be stabilized. Step S4: Use a road mixer to mix the phosphogypsum to be stabilized and the stabilizer to be used evenly. Mix the road mixer 2-4 times, and then use a grader to level the surface. Step S5: Use a bulldozer or loader to compact the phosphogypsum base 3-4 times, then use a double-drum roller to compact it 3-4 times, then use a single-drum vibratory roller to compact it 4-6 times, and finally use a rubber-tired roller to compact it 1-2 times. Step S6: Sprinkle water and cover the compacted phosphogypsum road for maintenance for more than 14 days.

10. A method for paving phosphogypsum roads, employing a plant-mixing construction process, characterized in that... include: Step S1: Determine the amount and optimal moisture content of the phosphogypsum stabilizer according to any one of claims 1 to 8, based on the phosphogypsum to be stabilized. Step S2: Use a soil stabilization mixer to mix the phosphogypsum to be stabilized, the phosphogypsum stabilizer, and the amount of water added according to the optimum moisture content, and stir until uniform. Step S3: Transport vehicles are used to transport the mixed stabilized phosphogypsum mixture to the construction site; Step S4: Use a paver to spread the stabilized phosphogypsum mixture onto the leveled subgrade or underlying layer surface; Step S5, then use a double-drum roller to compact 3-4 times, then use a single-drum vibratory roller to compact 4-6 times, and finally use a rubber-tired roller to compact 1-2 times. Step S6: Sprinkle water and cover the compacted phosphogypsum road for maintenance for more than 14 days.

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