A method for rapidly and harmlessly treating phosphogypsum

Abstract

The application discloses a method for rapidly and harmlessly treating phosphogypsum, and particularly relates to the harmless treatment technical field of industrial solid waste. The method comprises the following steps: mixing raw materials with an alkaline neutralizing agent, a trapping agent and an activating agent, adding a phosphorus solidifying agent and a fluorine solidifying agent, mixing, carbonizing and aging, and obtaining harmless phosphogypsum. The method adopts the alkaline neutralizing agent to rapidly neutralize free acid and improve the pH of the system; the trapping agent adsorbs heavy metals; the activating agent promotes As, Cd and the like to form a difficult-to-dissolve iron oxide gel or a precipitate; the phosphorus solidifying agent and the fluorine solidifying agent perform deep chemical precipitation to form a stable iron-calcium-phosphate / ferric fluoride composite solidified body. The functions of the agents are clear, and the agents have synergistic effects; the solidification effect of the agents on high water-solubility phosphorus, fluorine and various heavy metals is far better than that of a single or simply compounded agent system; and the leaching concentration can be reduced to a level far lower than the national standard.

Description

Technical Field

[0001] This invention relates to the field of industrial solid waste harmless treatment technology, specifically to a method for rapid harmless treatment of phosphogypsum. Background Technology

[0002] Phosphogypsum is a major industrial byproduct of wet-process phosphoric acid production, with approximately 4-5 tons of phosphogypsum produced for every ton of phosphoric acid produced. Because it contains residual phosphoric acid, fluorides, heavy metals (such as As, Cd, Pb, etc.), and radioactive nuclides, direct storage without effective treatment can easily lead to soil acidification, groundwater fluoride pollution, and ecological risks. It has been included in the "National Hazardous Waste List (2021 Edition)" (some highly polluting batches). Therefore, harmless treatment of phosphogypsum to meet relevant standards such as "GB / T32124-2024 Phosphogypsum" or "HJ / T 300-2007 Solid Waste Leaching Toxicity Leaching Method" is a prerequisite for its resource utilization.

[0003] Currently, the harmless treatment technologies for phosphogypsum are mainly divided into two categories: source control methods and end-of-pipe treatment methods. For example, Chinese patent CN119259663A proposes a source co-treatment method that simultaneously adds alkaline solid waste materials such as steel slag and red mud to the wet phosphoric acid filtration stage along with carbide slag. By optimizing washing conditions and two-stage liquid-phase reactions, the soluble phosphorus and fluorine content in phosphogypsum is reduced. Although this method can effectively improve the recovery rate of phosphorus and fluorine, it must be embedded in the phosphoric acid production process, relies on specific equipment modifications, and cannot be applied to historically stockpiled or dried phosphogypsum. Furthermore, it requires a supporting filtrate reuse system, resulting in high engineering complexity and making it difficult to promote and apply in existing stockpiles.

[0004] For stockpiled dry-based phosphogypsum, existing technologies mostly employ a combination of chemical stabilization and aging. For example, CN118954987A discloses a two-stage aging process: first, lime is used to neutralize the acidity, then a composite agent of calcium chloride and polyphosphate is added. After 20-30 hours of initial aging, a further 1-20 days of long-term static aging is required to release and solidify the eutectic phosphorus and fluorine. While this method can bring phosphogypsum up to the Class I general industrial solid waste standard, the treatment cycle is too long, it requires a large site area, the cost of polyphosphate is high, and the long-term aging process is significantly affected by environmental temperature and humidity, making it difficult to meet the needs of rapid industrial disposal.

[0005] To shorten treatment time, CN118403886A proposes a rapid, dry, and harmless treatment method. This method involves dry-mixing a multi-component agent, including a pH adjuster, passivating agent, particulate adsorbent (such as bentonite or red mud), and modified asbestos, with phosphogypsum. After biaxial vibration stirring, only 24 hours of controlled-humidity aging are required to achieve the required standards. While this method is simple, it has significant drawbacks: First, it relies on special adsorbent materials such as modified asbestos, resulting in a complex preparation process and potential health and environmental risks. Second, the pure dry-mix system lacks a liquid phase medium, leading to insufficient contact between the agents and pollutants, and limited solidification efficiency for highly polluting phosphogypsum (e.g., soluble phosphorus >100 mg / L, soluble fluorine >200 mg / L). Third, some agents (such as polyaluminum chloride and organic polymeric flocculants) are costly, hindering large-scale application.

[0006] Therefore, in response to the common problems of existing end-of-pipe treatment technologies, such as long treatment cycles, incomplete solidification of high concentrations of soluble phosphorus and fluorine, reliance on special or expensive agents, and poor process adaptability, there is an urgent need to develop a new method for the harmless treatment of phosphogypsum that is highly adaptable to raw materials, fast in processing, low in agent cost, has a thorough solidification effect, and is easy to promote industrially, so as to meet the urgent needs of current phosphogypsum stockpile management and large-scale disposal. Summary of the Invention

[0007] Therefore, the present invention provides a method for the rapid and harmless treatment of phosphogypsum to solve the problems in the prior art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] According to the present invention, a method for rapid and harmless treatment of phosphogypsum is provided, the method comprising:

[0010] Step 1: Test the phosphogypsum raw material for phosphorus, fluorine and heavy metals, weigh the phosphogypsum, weigh the solid reagents alkaline neutralizer, scavenger and activator according to the proportion, and put them into the mixer for mixing and reaction to obtain one-time stirred phosphogypsum.

[0011] Step 2: Add phosphorus fixative and fluorine fixative to the phosphogypsum obtained in Step 1, and then mix and react it in a mixer to obtain the treated phosphogypsum.

[0012] Step 3: The treated phosphogypsum obtained in Step 2 is aged to obtain harmless phosphogypsum.

[0013] In step one, the alkaline neutralizing agent is a calcium-containing composition, the trapping agent is fly ash, and the activator is an iron-containing composition; in step two, the phosphorus fixative is a polyferric composition, and the fluorine fixative is a calcium-containing composition.

[0014] In this invention, the phosphogypsum raw material has a soluble phosphorus content >100mg / L and a soluble fluorine content >200mg / L, which belongs to the category of high phosphorus and high fluorine content phosphogypsum raw materials in this field.

[0015] Furthermore, the amount of alkaline neutralizing agent added is 0.8-2% of the mass of phosphogypsum, and the effective calcium oxide content is ≥70%. The alkaline neutralizing agent is calcium oxide or a mixture of calcium oxide and soluble silicate; as an example, CaO:Na2SiO3 = (5-10):1 is preferred.

[0016] Furthermore, the amount of the trapping agent added is 1-10% of the mass of phosphogypsum.

[0017] Furthermore, the amount of activator added is 0.05-0.5% of the mass of phosphogypsum. As an example, ferric chloride is preferred as the activator.

[0018] Furthermore, the amount of phosphorus-fixing agent added is 1-3% of the mass of phosphogypsum.

[0019] Furthermore, the total iron content in the phosphorus-fixing agent is ≥10%. As an example, the phosphorus-fixing agent is preferably liquid polyferric sulfate, and the total iron content of the liquid polyferric sulfate is ≥10%.

[0020] Furthermore, the amount of the fluoride-fixing agent added is 1-5% of the mass of phosphogypsum. As an example, the fluoride-fixing agent is preferably a calcium chloride solution with a calcium chloride content of 30-50%.

[0021] Furthermore, in steps one and two, the mixer speed is 100-200 rpm, and the mixing time is 5-15 minutes.

[0022] Furthermore, the aging time in step three is 2-3 days.

[0023] Furthermore, the carbonation aging environment in step three is a CO2-rich atmosphere.

[0024] In the carbonation and aging device of the "treated phosphogypsum" obtained in step two, spread it evenly or form a material layer of a certain thickness (thickness 0.5-2 meters).

[0025] Industrial flue gas with a CO2 volume fraction of 5-20% (after dust removal and desulfurization pretreatment) is introduced into the device, and the flue gas introduction rate is controlled to maintain the CO2 concentration in the device within the range of 1-10% (v / v).

[0026] The relative humidity inside the device is controlled between 60% and 85%. This humidity range ensures that a liquid water film exists in the pores of the material to dissolve CO2, while avoiding excessive moisture that could cause the material to clump together.

[0027] Carry out at room temperature (15-40℃). The total carbonation and aging time is 2-3 days.

[0028] During the aging process, intermittent aeration or low-flow-rate continuous aeration is used, combined with intermittent turning (once every 12-24 hours) to break the surface crust and promote the diffusion of CO2 into the interior of the material.

[0029] The present invention has the following advantages:

[0030] This invention employs an alkaline neutralizing agent to rapidly neutralize free acid and raise the system's pH; a trapping agent to adsorb heavy metals; an activator to promote the formation of sparingly soluble iron oxide gels or precipitates such as As and Cd; and a phosphorus-fixing agent (liquid polyferric sulfate) and a fluoride-fixing agent (calcium chloride) to undergo deep chemical precipitation, forming a stable iron-calcium-phosphate / fluoride composite solidified body. Each agent has a clearly defined function and synergistic effect, demonstrating significant solidification effects on highly water-soluble phosphorus, fluoride, and various heavy metals. It is particularly suitable for pollution scenarios with high phosphorus (e.g., soluble phosphorus > 100 mg / L) and high fluoride (e.g., soluble fluoride > 200 mg / L), reducing the leaching concentration to levels far below national standards.

[0031] In the core reagents of this invention, the trapping agent is made from bulk solid waste fly ash, achieving "waste treatment with waste"; the alkaline neutralizing agent (calcium oxide or a mixture of calcium oxide and soluble silicate), activator (ferric chloride), phosphorus fixative (liquid polyferric sulfate), and fluoride fixative (calcium chloride) are all widely available and inexpensive common industrial chemicals. The overall reagent cost is low, and it does not use expensive or complexly modified special adsorbents, possessing significant economic advantages and being easy to promote industrially.

[0032] This invention employs a three-step method of "two-stage stirring + enhanced aging," with a total processing time of only 2-3 days. The entire process is carried out at ambient temperature and pressure, requiring only conventional stirring equipment and eliminating the need for high-temperature and high-pressure reactors, specialized twin-shaft vibrating mixers, or complex solid-liquid separation systems. The process is simple, with low equipment investment and operating / maintenance costs, easy operation, and readily adaptable to existing sites for technical modification and implementation.

[0033] This invention innovatively places the traditional aging process in a CO2-rich atmosphere. This not only promotes the deep stabilization of pollutants (especially fluorine) but also mineralizes and sequesters alkaline components such as free calcium in the product, forming a calcium carbonate coating layer that further strengthens the physical barrier. This step upgrades a simple "detoxification" technology to a synergistic "detoxification + carbon sequestration" technology, contributing to carbon neutrality while addressing environmental pollution, thus enhancing the technology's environmental value and potential economic benefits. Attached Figure Description

[0034] To more clearly illustrate the embodiments of the present invention or the technical solutions in 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 merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0035] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0036] Figure 1 The flowchart shows a method for rapid and harmless treatment of phosphogypsum provided in Embodiment 1 of the present invention. Detailed Implementation

[0037] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Calcium oxide: Class III conforming to HG / T4205-2024 "Industrial Calcium Oxide";

[0039] Fly ash: Complies with Grade II of GB / T1596-2017 "Fly ash for cement and concrete";

[0040] Sodium silicate: Qualified product L-250-37 of liquid sodium silicate conforming to GB / T4209-2022 "Industrial Sodium Silicate";

[0041] Ferric chloride: Qualified Class II anhydrous ferric chloride that conforms to GB / T1621-2023 "Industrial Ferric Chloride";

[0042] Liquid polyferric sulfate: A qualified liquid product conforming to GB / T14591-2016 "Water Treatment Agent Polyferric Sulfate";

[0043] Calcium chloride: Anhydrous calcium chloride type II conforming to GB / T26520-2021 "Industrial Calcium Chloride".

[0044] Unless otherwise specified in the embodiments of this invention, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available products; different manufacturers and models of raw materials do not affect the implementation of the technical solution or the achievement of the technical effect of this invention.

[0045] Example 1

[0046] This embodiment provides a method for the rapid and harmless treatment of phosphogypsum, the process of which is as follows: Figure 1 As shown:

[0047] S1. The phosphogypsum raw material was tested. The soluble phosphorus content was 147 mg / L, the soluble fluorine content was 271 mg / L, and the heavy metal content exceeded the standard and was unqualified. 600g of phosphogypsum, 10.8g of calcium oxide (effective calcium oxide content 80%, the same below), 2g of Na2SiO3, 24g of fly ash, and 1.2g of anhydrous ferric chloride were weighed and poured into a mixer and mixed evenly to obtain a single-stage phosphogypsum.

[0048] S2. Add 12g of liquid polyferric sulfate (12% total iron, the same applies below) and 10.8g of 40% calcium chloride solution to the phosphogypsum that was stirred once in step S1 to obtain the treated phosphogypsum.

[0049] S3. The treated phosphogypsum obtained in step S2 is aged for 3 days under carbonation aging conditions to obtain harmless phosphogypsum.

[0050] Carbonation aging conditions: Spread the treated phosphogypsum obtained in step S2 to a thickness of 1.5m, and introduce industrial flue gas containing 10% CO2 volume fraction after dust removal and desulfurization pretreatment. Maintain the CO2 concentration in the device at about 5% (v / v), control the relative humidity in the device at about 70%, and stir once every 24 hours. The total carbonation aging time at room temperature is 2-3 days.

[0051] Example 2

[0052] This embodiment provides a method for the rapid and harmless treatment of phosphogypsum:

[0053] S1. Test the phosphogypsum raw material. The soluble phosphorus content is 67mg / L, the soluble fluorine content is 71mg / L, and the heavy metal content is within the qualified range. Weigh 600g of phosphogypsum, 4.8g of calcium oxide, 6g of fly ash, and 0.6g of anhydrous ferric chloride. Pour them into a mixer and mix well to obtain a single-stage phosphogypsum.

[0054] S2. Add 7.2g of liquid polyferric sulfate and 3g of 40% calcium chloride solution to the phosphogypsum that was stirred once in step S1 to obtain the treated phosphogypsum.

[0055] S3. The treated phosphogypsum obtained in step S2 is aged for 3 days under carbonation aging conditions (aging conditions are the same as in Example 1) to obtain harmless phosphogypsum.

[0056] Example 3

[0057] This embodiment provides a method for the rapid and harmless treatment of phosphogypsum:

[0058] S1. Test the phosphogypsum raw material. The soluble phosphorus content is 104 mg / L, the soluble fluorine content is 189 mg / L, and the heavy metal content is within the qualified range. Weigh 600g of phosphogypsum, 6g of calcium oxide, 0.6g of Na2SiO3, 18g of fly ash, and 0.9g of anhydrous ferric chloride. Pour them into a mixer and mix well to obtain a single-stage phosphogypsum.

[0059] S2. Add 10.8g of liquid polyferric sulfate and 7.5g of 40% calcium chloride solution to the phosphogypsum that was stirred once in step S1 to obtain the treated phosphogypsum.

[0060] S3. The treated phosphogypsum obtained in step S2 is aged for 3 days under carbonation aging conditions (aging conditions are the same as in Example 1) to obtain harmless phosphogypsum.

[0061] Comparative Example 1

[0062] This comparative example provides a method for the rapid and harmless treatment of phosphogypsum:

[0063] In step one, fly ash is replaced with an equal amount of bentonite, and everything else is exactly the same as in Example 1.

[0064] Comparative Example 2

[0065] This comparative example provides a method for the rapid and harmless treatment of phosphogypsum:

[0066] In step two, liquid polyferric sulfate is replaced with sodium dipolyphosphate, otherwise it is completely consistent with Example 1.

[0067] Comparative Example 3

[0068] This comparative example provides a method for the rapid and harmless treatment of phosphogypsum:

[0069] In step two, no liquid polyferric sulfate is added; otherwise, it is completely consistent with Example 1.

[0070] Comparative Example 4

[0071] This comparative example provides a method for the rapid and harmless treatment of phosphogypsum:

[0072] In step three, the aging process involves placing the product in a dry and ventilated environment for three days, without using carbonation aging. Otherwise, it is completely consistent with Example 1.

[0073] Comparative Example 5

[0074] This comparative example provides a method for the rapid and harmless treatment of phosphogypsum:

[0075] No trapping agents, activators, or fluoride fixatives were added; the alkali neutralizers were 24g of calcium oxide and 4.5g of Na2SiO3, and 33g of liquid polyferric sulfate was used. Everything else was exactly the same as in Example 1.

[0076] Comparative Example 6

[0077] This comparative example provides a method for the rapid and harmless treatment of phosphogypsum:

[0078] No trapping agents or activators were added; the alkali neutralizing agent used was 18g of calcium oxide, 3.3g of Na2SiO3, 9.0g of 40% calcium chloride solution, and 24g of liquid polyferric sulfate. Everything else was exactly the same as in Example 1.

[0079] Comparative Example 7

[0080] This comparative example provides a method for the rapid and harmless treatment of phosphogypsum:

[0081] No activator was added; the alkali neutralizer used was 18g of calcium oxide, 3.3g of Na2SiO3, 9.0g of 40% calcium chloride solution, 24g of fly ash, and 27g of liquid polyferric sulfate. Everything else was exactly the same as in Example 1.

[0082] Comparative Example 8

[0083] This comparative example provides a method for the rapid and harmless treatment of phosphogypsum:

[0084] The same as in Example 2 was used for phosphogypsum; 100 parts of dry phosphogypsum, 6 parts of particulate adsorbent (3 parts diatomaceous earth, 3 parts red mud), 0.4 parts of passivating agent (0.2 parts potassium aluminum sulfate, 0.1 parts calcium chloride, 0.1 parts polyaluminum chloride), and several parts of pH adjuster (to adjust the pH of the leachate to 6) were accurately weighed. 9) 0.6 parts of the supplement (take asbestos powder, and add 0.2% charcoal powder, 0.2% silica, 0.5% epoxidized linseed oil, 0.3% sodium lauryl sulfate, 0.4% silane coupling agent KH792, and appropriate amount of deionized water. Stir at 400 rpm and 40°C for 30 minutes, then remove and dry to obtain modified asbestos) for later use.

[0085] 100 parts of the above-mentioned dry phosphogypsum, 0.4 parts of passivating agent, 0.6 parts of supplement agent, and several parts of pH adjuster were poured into a biaxial vibrating mixer and stirred for 7 minutes. Then, 6 parts of particulate adsorbent were added and stirred for 7 minutes. The thoroughly mixed material was placed under the conditions of temperature (24±3℃) and humidity (55±5%) for 24 hours to obtain harmless phosphogypsum.

[0086] Comparative Example 9

[0087] This comparative example provides a method for the rapid and harmless treatment of phosphogypsum:

[0088] The phosphogypsum was treated in the same way as in Example 1; other methods were used in accordance with the method of Comparative Example 8 to obtain harmless phosphogypsum.

[0089] Experimental Example 1

[0090] The harmless phosphogypsum obtained in Examples 1-3 and Comparative Examples 1-9 was tested, and the results are shown in Table 1.

[0091] pH value of leachate: GB / T 15555.12-1995;

[0092] Total phosphorus concentration in leachate: GB / T32124-2024;

[0093] Fluoride concentration in leachate: GB / T32124-2024;

[0094] Heavy metal leaching concentration: atomic absorption spectrometry.

[0095] Table 1. Test Results of Harmless Phosphogypsum

[0096]

[0097] Table 1 shows that the trapping agent not only plays a role in fixing fluorine and phosphorus but also has a significant effect on the solidification of heavy metals. The activator promotes the solidification of phosphorus and fluorine in high-fluorine and high-phosphorus phosphogypsum. Through multiple solidification processes involving trapping agents, activators, and solidifying agents, harmless phosphogypsum is effectively obtained. The total phosphorus content in Comparative Example 7 (lacking only the activator) was not significantly improved compared to Comparative Example 6 (lacking both the activator and the trapping agent), proving that the phosphorus-fixing contribution of the activator cannot be replaced by simply adding an alkali neutralizer or phosphorus-fixing agent; the activator (ferric chloride) is indispensable. In Comparative Example 5, lacking all three, the fluoride content reached as high as 23.86%. In Comparative Example 6, after adding the fluoride-fixing agent (calcium chloride), the fluoride content decreased to 14.52 but still exceeded the standard. This shows that only when all three are present (Example 1) can the fluoride content be reduced to a reasonable range. In Comparative Example 1, fly ash was replaced with bentonite. Although both have adsorption effects, all indicators exceeded the standard, indicating that the core function of fly ash in this system is not simply physical adsorption, but rather its porous structure of Fe... 3+ / Ca 2+ Hydrolysis and precipitation provide nucleation sites, and their own slightly alkaline nature helps maintain a locally high pH environment. As a structural framework, it prevents the semi-dry process materials from agglomerating, ensuring uniform mass transfer. In Comparative Example 2, replacing the phosphorus-fixing agent with liquid polyferric sulfate did not achieve the expected results, indicating that to achieve phosphorus fixation in a short time, a special phosphorus-fixing agent is required. Ordinary phosphorus-fixing agents not only fail to accelerate the process but may even cause problems due to the complexation of Ca.2+ Interference with precipitation occurs. As shown in Comparative Example 3, the absence of a phosphorus-fixing agent resulted in better performance than the addition of sodium dipolyphosphate. Comparative Example 4 demonstrates that even with the same chemical curing steps, the lack of a carbonation step leads to inconsistent fluoride leaching concentrations. Comparative Examples 8 and 9 show that existing technologies are effective for low-content dry-based phosphogypsum but less effective for high-content dry-based phosphogypsum.

[0098] Experiment Example 2

[0099] 28-day compressive strength:

[0100] The harmless phosphogypsum obtained in Examples 1-3 and Comparative Examples 1-9 was pressed into 40×40×40 mm test blocks with 5% cement and tested after standard curing for 28 days (GB / T 17671).

[0101] Cl - Content (water solubility): silver nitrate titration method (GB / T 176).

[0102] The results are shown in Table 2.

[0103] Table 2 Compressive strength and Cl - Content Results Table

[0104]

[0105] Table 2 shows that carbonation aging to form carbonate precipitates from remaining calcium salts can improve the compressive strength of phosphogypsum blocks. Adding silicates has a certain effect on improving the compressive strength of the blocks, while free fluorine in phosphogypsum significantly reduces the compressive strength. The fluoride concentration in Example 2 is the lowest among the three examples, yet its compressive strength is not the highest. This is because Na2SiO3 was not added in Example 2, and Na2SiO3 has a significant positive effect on subsequent compressive strength, further enhancing it. Although sodium dipolyphosphate affects the subsequent curing of fluorides by the fluorinating agent, resulting in a high free fluorine content, it has a positive effect on enhancing subsequent compressive strength. The interaction between the various agents not only minimizes the content of phosphorus, fluorine, and heavy metals but also increases the compressive strength of the blocks in subsequent applications.

[0106] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for the rapid and harmless treatment of phosphogypsum, characterized in that, The method includes: Step 1: Weigh the alkaline neutralizer, trapping agent and activator according to the proportion, and put them into the mixer for mixing and reaction to obtain a single-stage phosphogypsum. Step 2: Add phosphorus fixative and fluorine fixative to the phosphogypsum obtained in Step 1, and then mix and react it in a mixer to obtain the treated phosphogypsum. Step 3: The treated phosphogypsum obtained in Step 2 is aged to obtain harmless phosphogypsum. In step one, the alkaline neutralizing agent is a calcium-containing composition, the trapping agent is fly ash, and the activator is ferric chloride; in step two, the phosphorus-fixing agent is liquid polyferric sulfate, and the fluorine-fixing agent is a calcium-containing composition; in step three, the aging process is carbonation aging, the aging environment is a CO2-rich atmosphere with a CO2 concentration of 1-10% (v / v), the relative humidity is controlled at 60-85%, and intermittent stirring is carried out during the aging process; the phosphogypsum raw material has a soluble phosphorus content >100mg / L and a soluble fluorine content >200mg / L.

2. The method for rapid and harmless treatment of phosphogypsum according to claim 1, characterized in that, The amount of alkaline neutralizing agent added is 0.8-2% of the mass of phosphogypsum, and the effective calcium oxide content is ≥70%.

3. The method for rapid and harmless treatment of phosphogypsum according to claim 1, characterized in that, The amount of the trapping agent added is 1-10% of the mass of phosphogypsum.

4. The method for rapid and harmless treatment of phosphogypsum according to claim 1, characterized in that, The amount of activator added is 0.05-0.5% of the mass of phosphogypsum.

5. The method for rapid and harmless treatment of phosphogypsum according to claim 1, characterized in that, The amount of phosphorus-fixing agent added is 1-3% of the mass of phosphogypsum.

6. The method for rapid and harmless treatment of phosphogypsum according to claim 5, characterized in that, The total iron content in the phosphorus fixative is ≥10%.

7. The method for rapid and harmless treatment of phosphogypsum according to claim 1, characterized in that, The amount of the fluoride-fixing agent added is 1-5% of the mass of phosphogypsum.

8. The method for rapid and harmless treatment of phosphogypsum according to claim 1, characterized in that, In steps one and two, the mixer speed is 100-200 rpm, and the mixing time is 5-15 minutes.

9. The method for rapid and harmless treatment of phosphogypsum according to claim 1, characterized in that, The aging time in step three is 2-3 days.

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