Ardealite harmless treatment device, treatment process and application of ardealite harmless treatment device

Abstract

The invention relates to the technical field of ardealite building new material production, in particular to an ardealite innocent treatment device and process and application of the ardealite innocent treatment device and process. The ardealite innocent treatment device comprises an aggregate bin, a powder bin, a powder stirrer, a conveyor, a mixing stirrer, a discharging bin, a water storage tank, an ardealite solidified body bin and an ardealite solidifying and air-drying all-in-one machine; the phosphogypsum raw material crusher and the phosphogypsum curing and air-drying all-in-one machine are arranged in the treatment device, phosphogypsum harmless treatment is achieved through the device with the structure, phosphogypsum crushing, harmless treatment and other procedures are added to an existing stirring station, and phosphogypsum is subjected to crushing and harmless treatment by arranging the phosphogypsum raw material crusher, the phosphogypsum curing and air-drying all-in-one machine and other devices in the treatment device; the ardealite harmless treatment technology is designed, the ardealite can be uniformly mixed with other building materials, the product quality is improved, the ardealite harmless treatment technology is designed, the material formed by the technology forms a set of complete new technology capable of being popularized from manufacturing to application, and the industrial and large-scale application performance is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of production of new phosphogypsum building materials, and in particular to a phosphogypsum harmless treatment device, a treatment process and applications thereof. Background Art

[0002] Phosphogypsum is a byproduct of the wet process of phosphoric acid production from phosphate rock. Every ton of phosphoric acid produced generates approximately 5 tons of phosphogypsum. Unused phosphogypsum is primarily stockpiled, occupying significant land. Residual impurities such as acid, phosphorus, fluorine, and organic matter can also pollute the land and groundwater with rainwater. 54% of phosphogypsum stockpiles present ecological and environmental risks. Therefore, the safe disposal and comprehensive utilization of phosphogypsum, coupled with the need for scale-up, are pressing challenges.

[0003] The primary comprehensive utilization of phosphogypsum is in the manufacture of building materials, including cement retarders, gypsum board, gypsum blocks, and gypsum mortar, but its comprehensive utilization rate is relatively low. In contrast, highway construction is a stable, multi-site, long, and extensive project. The increasing shortage of traditional raw materials has led to increasingly expensive and difficult-to-obtain natural aggregates. Using phosphogypsum as a road material not only allows for rapid and large-scale utilization of phosphogypsum, but also promotes the green and sustainable development of road infrastructure, which is of great practical significance.

[0004] The invention (Application No. 202311277836.1), filed on September 28, 2023, relates to a phosphogypsum curing agent, a phosphogypsum solidified body, and their applications. The invention mentions a phosphogypsum solidified body, wherein the mass ratio of phosphogypsum to phosphogypsum curing agent is 100:25-40. The phosphogypsum solidified body is used in road bases, riverbank slopes, pool bottoms, or the base of roller-compacted earth-rock dams. Current mixing plants consist solely of an aggregate silo, a powder tank, a mixing silo, a discharge silo, a stirrer, and an admixture silo. Due to the unique properties of the phosphogypsum solidified body, the phosphogypsum and phosphogypsum curing agent must be mixed sequentially. Therefore, the use of phosphogypsum in the preparation of new materials cannot be achieved with current mixing plants. Adaptive modification is required based on the physical and chemical properties of the phosphogypsum raw material and the production mix ratio of the phosphogypsum-based new material.

[0005] The invention applied for on February 7, 2025 (publication number CN 119858239 A) discloses a phosphogypsum mixing station, which includes a powder batching machine, an aggregate batching machine, a curing agent metering device, a conveying device, a mixing main unit and a finished product silo. The powder batching machine, the aggregate batching machine and the curing agent metering device put the materials into the first conveying device according to the mix ratio, which can realize accurate measurement and stable conveying of each material. Then, each material enters the mixing main unit for continuous vibration stirring, and then the finished material is transferred to the finished product silo through the second conveying device. In this process, the anti-segregation mechanism can greatly reduce the segregation of the finished product. In the present invention, each batching mechanism can be stacked according to the actual site, and the continuous stirring of the mixing main unit can greatly improve the production efficiency.

[0006] Although this mixing station is also designed for phosphogypsum, it is not suitable for the production of the new phosphogypsum material described in "A phosphogypsum curing agent, phosphogypsum solidified body and its application" for two reasons: First, phosphogypsum contains a lot of impurities. The main components of phosphogypsum are SO3 and CaO, accounting for 86.86%~93.95% of the dry basis mass fraction. It also contains varying amounts of impurities such as P2O5, Fe2O3, F, etc. In addition, phosphogypsum also contains some organic carbon, unreacted apatite, heavy metals and radioactive nuclides. Among them, there are three types of impurities that have a greater impact on the quality of phosphogypsum products, namely P2O5, soluble fluorides and organic impurities; impurities with greater impact on the environment include heavy metals, radionuclides, and soluble phosphorus and fluorides. Although the impurities in phosphogypsum are relatively low in content, they will have a significant impact on the quality of phosphogypsum products and even directly determine whether phosphogypsum can be processed into certain products. This patent (publication number CN 119858239 A) does not involve pre-treatment equipment for phosphogypsum in the mixing station. If phosphogypsum is directly used to make building materials for mixing, the building materials will continuously emit harmful substances due to the poor water stability and easy expansion of phosphogypsum when absorbing water. Long-term contact with phosphogypsum may cause human disease or death. Therefore, strictly speaking, it does not meet environmental protection standards.

[0007] Second, the composition of phosphogypsum fluctuates greatly. Different manufacturers use different phosphate rocks and have different production process controls. The moisture content, particle size, particle morphology and impurity content of the final phosphogypsum are all different, causing the phosphogypsum to often clump tightly and cannot be directly mixed with aggregates, powders and other roadbed materials, and needs to be processed in advance.

[0008] If the phosphogypsum is processed in advance and then mixed into the mixing station, new problems will arise, such as increased costs and how to transport the raw materials to the mixing station. How to design an integrated, multifunctional, complete set of large-scale phosphogypsum harmless treatment equipment and treatment process is a technical problem that needs to be solved urgently. Summary of the Invention

[0009] To solve the above-mentioned technical problems, the purpose of the present invention is to provide a harmless treatment device, treatment process, and application of phosphogypsum. This technology focuses on the resource utilization of bulk industrial solid waste. Based on the research on high-quality water-stabilization and long-term solidification technology of harmful impurities in phosphogypsum, it develops a new equipment system for the resource utilization of phosphogypsum from raw materials to finished products. It clarifies the technical process for the entire harmless treatment process of phosphogypsum building materials from mixing stations to road construction, and ensures the application performance of the developed new phosphogypsum-based materials in industrial-scale scenarios such as roads, backfill, and underground filling. As a component of solving the problem of large-scale application of phosphogypsum, efficient and harmless treatment technology for phosphogypsum has an important theoretical basis and applied research significance.

[0010] In order to achieve the above object, the technical solution of the present invention is as follows: A harmless treatment device for phosphogypsum includes an aggregate silo, a powder silo, a powder mixer, a conveyor, a mixer, a discharge silo, and a water reservoir. The conveyor is connected to the discharge end of the aggregate silo and the feed end of the mixer, the powder silo is connected to the powder mixer, the powder mixer is connected to the feed end of the mixer, the discharge silo is connected to the discharge end of the mixer, and the water reservoir is connected to the mixer. The invention is characterized in that it further comprises a phosphogypsum solidified body silo placed at the upstream end of the aggregate silo, a phosphogypsum solidified air-drying integrated machine connected to the phosphogypsum solidified body silo and located at the upstream end thereof, and a phosphogypsum raw material crusher located at the upstream end of the phosphogypsum solidified air-drying integrated machine, wherein the phosphogypsum solidified body is harmless phosphogypsum formed by the thorough mixing reaction of phosphogypsum and a curing agent. The phosphogypsum solidification and air-drying integrated machine mainly consists of a diluter, an atomizer, a stirring and dispersing tank and a dryer, and is mainly used for the harmlessness of phosphogypsum. The dryer is sleeved on the outer periphery of the stirring and dispersing tank, the diluter is installed on the frame outside the stirring and dispersing tank, the atomizer is connected between the diluter and the stirring and dispersing tank, and a raw material inlet and a solidified body outlet are provided on the stirring and dispersing tank. The phosphogypsum raw material crusher is connected to the raw material inlet, and the solidified body outlet is placed at the feed end of the phosphogypsum solidified body silo.

[0011] The phosphogypsum curing and air-drying machine is also connected to an admixture dosing machine for filling the phosphogypsum curing agent and supplying it to the diluter.

[0012] Furthermore, the phosphogypsum raw material crusher adopts a hammer crusher or a hammer crusher for crushing sticky materials.

[0013] Furthermore, a propulsion stirring blade and a blade drive are installed in the diluter. The blade drive is installed on the top of the diluter. The shaft end of the propulsion stirring blade is connected to the blade drive, and the stirring end is deep into the diluter.

[0014] Furthermore, the atomizer includes an ultrasonic atomizer body, an atomizer tube, and an atomizer nozzle. The fluid inlet of the ultrasonic atomizer body is connected to the diluter, the fluid channel of the ultrasonic atomizer body is connected to the atomizer tube, and the atomizer tubes are provided in two or more groups and are evenly arranged along the length direction of the stirring and dispersing tank. The atomizer nozzle is fixed at the front end of the atomizer tube and placed in the stirring and dispersing tank.

[0015] Furthermore, a spiral-ribbon stirring blade is installed on the stirring shaft in the stirring and dispersing tank.

[0016] Furthermore, the phosphogypsum solidified body silo includes a funnel-shaped silo body and a rotary vibration arch-breaking assembly. The funnel-shaped silo body is divided into an outer shell layer and an inner shell layer. The cross-section of the inner shell layer is an inverted trapezoidal shape. The rotary vibration arch-breaking assembly is installed at the discharge port of the inner shell layer to control the vibration arch-breaking discharge of the phosphogypsum solidified body.

[0017] Furthermore, there is at least one group of aggregate silos, which are arranged side by side with the funnel-shaped silo body. The starting end of the conveyor is placed below the discharge port of the funnel-shaped silo body and extends along the setting direction of the aggregate silo and extends to the feed end of the mixer.

[0018] Furthermore, the mixing mixer is composed of two groups of mixing cylinders stacked up and down, the additive dosing machine and the water reservoir are connected to the upper mixing cylinder, the end of the conveyor is connected to the upper mixing cylinder, and the outlet of the lower mixing cylinder is connected to the discharge bin.

[0019] A harmless treatment process for phosphogypsum comprises the following steps: S1. Test the moisture content of the phosphogypsum raw material. When the moisture content is less than 15%, use a hammer crusher with a discharge particle size of 0.1-2mm. When the moisture content of the phosphogypsum raw material is greater than 15%, use a hammer crusher that can crush sticky materials with a discharge particle size of 0.1-5mm. S2. Use a crusher to crush the phosphogypsum raw materials and transport them to a phosphogypsum solidification and air-drying machine for harmless treatment; S3. Add 5 to 10 parts of water to each part of the curing agent liquid and dilute it in an admixture doser. After dilution, supply the diluter. Turn on the propeller stirring blade to stir during dilution. Then, turn on the atomizer to spray the curing agent into the stirring and dispersing tank. The atomized particle size is less than 10 microns and the atomization rate is 40 ml / min. The atomization spraying and stirring and dispersing are performed simultaneously. After the phosphogypsum is uniformly solidified and harmless, turn on the dryer to dry it. The drying temperature range is 50° C. to 300° C. After drying, a solidified phosphogypsum body with a moisture content of less than 15% is formed. S4, the mixing and dispersing tank discharges the solidified phosphogypsum solidified body and inputs it into the phosphogypsum solidified body silo, S5. Simultaneously open the phosphogypsum solidification material bin and the aggregate bin. The aggregate bin is loaded with construction aggregates. The solidified phosphogypsum solidification material and construction aggregates are discharged onto the conveyor according to the metered amount. The conveyor transports the mixed materials to the mixing mixer. S6, the powder silo and powder mixer are running at the same time, mixing cement and other powders according to the measurement and then feeding them into the mixer. S7. All materials, admixtures and water are mixed and passed through upper and lower mixing tanks to be fully mixed. After mixing, the phosphogypsum-based new material is obtained, and the phosphogypsum-based new material is discharged into the unloading bin.

[0020] On the other hand, the application of harmless phosphogypsum-based new materials obtained by harmless treatment process in roadbed construction includes the following steps: S1. Use a transport vehicle with a short bed to load the phosphogypsum-based new materials from the unloading bin. S2. During transportation, tarpaulin should be used to cover the material. When the ambient temperature is higher than 30°C, the time from mixing to transportation to on-site paving should not exceed 2 hours. If it exceeds 3 hours, it should be disposed of as waste. When the ambient temperature is lower than 30°C and higher than 15°C, the time from mixing to transportation to on-site paving should not exceed 3 hours. When the ambient temperature is lower than 15°C, the time from mixing to transportation to on-site paving should exceed 4 hours. S3. When unloading, the transport vehicle increases the unloading angle and is equipped with a vibrator to assist in unloading. S4. When paving, adopt the method of two-layer continuous paving construction, and equip each layer with independent paving and rolling equipment. Ensure sufficient paving thickness. After rolling and forming, the paving thickness of each layer should be no less than 160mm. During the paving process, keep the paver speed controlled at 1.0-3.0m / min. Maintain transverse joints during paving. During construction, the distance between the front and rear pavers should not be greater than 10m, and the adjacent construction sections should overlap by 30cm to 40cm in the longitudinal direction. When the width of the stable layer is 11~12m, the length of each flow operation section should be 300m; when the width of the stable layer is greater than 12m, the length of the operation section should be shortened accordingly. S5. When rolling, compact according to the process of steady pressure - strong vibration - weak vibration - steady pressure, and compact according to the compaction direction of first the outside and then the inside. During hot construction, if the roadbed material becomes loose or moves during the rolling process, it should be moistened with water mist and stirred evenly, and adjusted to the moisture content of the factory before compaction. S6. During curing, after the phosphogypsum stabilization layer is compacted and passes the compaction inspection, it shall be covered and cured within 2 hours. The curing time is 7 to 14 days.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. Combining the existing pavement base water-stabilizing material mixing station equipment, the phosphogypsum machine pavement base material equipment is improved, and the design is combined with the existing equipment to reduce equipment costs.

[0022] 2. To address the process requirements for solidifying phosphogypsum, improving water stability, and reducing pollutant leaching, a solidification and dehydration unit was added after grinding. This integrated system utilizes essential components such as propeller agitation and dilution, ultrasonic atomization, ribbon agitation, and heat pipe dehydration. Key technologies for each step have been identified, enabling efficient processing of phosphogypsum from raw material to solidified form. After solidification, the harmful components are decomposed, resulting in a new phosphogypsum-based material.

[0023] 3. Aiming at the problem of arching and easy clogging of materials in the existing phosphogypsum silo, a new gypsum solidification silo is designed at the discharge port of this equipment. The characteristic of the axis trajectory of the Leroy triangle when rotating is a circular motion is utilized, and the stirring shaft is installed to the axis of the Leroy triangle. It rotates continuously around the center point while rotating, thereby generating a vibration effect, realizing stirring and vibration at the same time, improving the silo structure, and improving the discharge efficiency of the discharge port compared with the original equipment, and the material falls more smoothly.

[0024] 4. Taking into full consideration the characteristics of phosphogypsum, such as high impurities, large fluctuations in composition, and easy agglomeration, phosphogypsum raw material crushers, phosphogypsum solidification and air-drying machines and other equipment are installed in the production equipment to carry out harmless pretreatment of phosphogypsum to ensure that it can be evenly mixed with other roadbed materials and improve product quality.

[0025] 5. Some existing mixing plants do not treat impurities in phosphogypsum. Direct mixing causes the roadbed material to emit harmful substances, which does not meet environmental standards. This invention reduces the generation of harmful substances by pre-treating the phosphogypsum, making the produced phosphogypsum-based new material more environmentally friendly and less harmful to the environment and human health.

[0026] 6. Based on the physical and chemical properties of phosphogypsum and its harmless properties, combined with the existing road paving application process, the application technology of new phosphogypsum-based materials in roadbed construction is proposed. It is adapted to the existing engineering technology, can reduce the consumption of natural aggregates and road construction costs, promote the high-value utilization of phosphogypsum, and provide a theoretical and practical basis for phosphogypsum road paving. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the top view of the layout 1 of the harmless treatment device for phosphogypsum; Figure 2 A schematic diagram of the three-dimensional structure of the layout 1 of the harmless treatment device for phosphogypsum; Figure 3 This is a schematic diagram of the main structure of the layout 2 of the harmless treatment device for phosphogypsum; Figure 4 This is a schematic diagram of the planar structure of pouring phosphogypsum raw materials into the phosphogypsum raw material crusher; Figure 5 This is a schematic diagram of the top view of the structure of the phosphogypsum curing and air-drying machine; Figure 6 This is a cross-sectional structural diagram of the phosphogypsum curing and air-drying machine; Figure 7 This is a simplified side view of the atomizer installed on the stirring dispersion tank; Figure 8 This is a schematic diagram of the main structure of the admixture dosing machine; Figure 9 It is a schematic diagram of the main structure of the mixing mixer; Figure 10 These are the vector diagrams and streamline diagrams of the phosphogypsum curing and air-drying machine analyzed using ANSYS software, where a is the longitudinal section velocity cloud diagram, b is the longitudinal section velocity streamline diagram, c is the longitudinal section two-phase cloud diagram, and d is the cross-section cloud diagram vector diagram. DETAILED DESCRIPTION

[0028] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific embodiments.

[0029] like Figure 1 — Figure 10 As shown, a harmless treatment device for phosphogypsum includes an aggregate silo 1, a powder silo 2, a powder mixer 3, a conveyor 4, a mixing mixer 5, a discharge silo 6 and a water reservoir 7. The conveyor 4 is connected to the discharge end of the aggregate silo 1 and the feed end of the mixing mixer 5, the powder silo 2 is connected to the powder mixer 3, the powder mixer 3 is connected to the feed end of the mixing mixer 5, the discharge silo 6 is connected to the discharge end of the mixing mixer 5, and the water reservoir 7 is connected to the mixing mixer 5.

[0030] On the basis of the above existing mixing station, it also includes a phosphogypsum solidified body silo 8 placed at the upstream end of the aggregate silo 1, a phosphogypsum solidified body air-drying integrated machine 9 connected to the phosphogypsum solidified body silo and located at its upstream end, and a phosphogypsum raw material crusher 10 located at the upstream end of the phosphogypsum solidified body air-drying integrated machine. The phosphogypsum solidified body silo is also connected to the outside of the phosphogypsum solidified body air-drying integrated machine, which is used to fill the phosphogypsum solidifying agent and supply it to the diluter.

[0031] The admixture dosing machine 11 includes a curing agent mixing tank 11-1, a curing agent mother liquid tank 11-2, a temporary storage tank 11-3, and a reduction metering scale 11-4. After the phosphogypsum curing agent and water are mixed in proportion, the phosphogypsum raw material is supplied for curing and stirring the phosphogypsum.

[0032] The admixture dosing machines 11 are divided into two groups. The first group, located next to the integrated phosphogypsum curing and air-drying machine 9, fills, dilutes, and stores a specialized curing agent used for curing and air-drying phosphogypsum. This curing agent is described in patent application publication number CN 117303846 A. The second group of admixtures is commonly used in existing slurry mixing plants. The modified admixture dosing machine, designed next to the mixer 5, supplies the mixer with common slurry admixtures, including lubricants, fluid loss additives, flocculants, thickeners, water reducers, weighting agents, retarders, and defoamers.

[0033] The structural layout of the entire mixing station is as follows Figures 1 to 3 As shown, the entire mixing station can be Figure 1 、 Figure 2 The layout shown is more space-saving and occupies less area. Figure 3 As shown, a straight-line layout is used to facilitate equipment installation.

[0034] The phosphogypsum raw material crusher 10 utilizes a hammer crusher, a machine that uses high-speed rotating hammers to impact the material, crushing it along vulnerable areas such as natural cracks, bedding planes, and cleavage planes. The hammers are freely suspended on a turntable and driven by the hammers to rotate, crushing the material. The hammer crusher utilizes a grate-less design, allowing the output particle size to be adjusted by adjusting the grate gap. This grate-less design prevents wet material from clogging the discharge port. The hammer crusher is suitable for a wide range of materials. When processing wet materials, the rotor is equipped with a scraper system to scrape away wet material adhering to the cavity wall, preventing clogging. Based on the characteristics of phosphogypsum in a particular region, a hammer crusher based on this principle is most suitable for crushing phosphogypsum raw materials with a moisture content of less than 15%. The requirements for 0.6mm sieve openings are ≥80% and 2.36mm sieve openings are ≥90%.

[0035] The phosphogypsum raw material crusher 10 can also employ a hammer crusher for crushing sticky and wet materials. Fresh phosphogypsum has a moisture content greater than 25%, making it a sticky and wet material prone to clogging. To improve the hammer crusher's adaptability to sticky and wet materials, a hammer crusher for crushing sticky and wet materials is employed. The crusher's housing houses a rotor, with a crawler-type rotating strike plate mounted in front of the rotor, serving as a crushing plate. This strike plate prevents material from accumulating at the crushing chamber entrance. Material adhering to the strike plate is swept away by the hammers. The strike plate is driven by a separate motor via a rotating shaft. A pad is located at the bottom of the strike plate to withstand the impact of the hammers. When material is fed onto the rotating strike plate, it is forced into the rotor's range of action. To prevent clogging, a grate screen is typically not provided beneath the rotor. Instead, a cleaning device is provided behind the rotor, consisting of a vertical, closed chain belt with a transverse scraper mounted on it. Driven by a separate motor, the chain belt rakes away material accumulated behind the rotor after crushing for easy removal, while also scraping off material adhering to the housing wall. The hammer crusher for crushing sticky and wet materials meets the requirements of 0.6mm sieve hole ≥80%; 2.36mm sieve hole ≥90%.

[0036] The phosphogypsum curing and air-drying machine 9 primarily consists of a diluter 90, an atomizer 91, a mixing and dispersing tank 92, and a dryer 93. The dryer 93 is mounted on the outer periphery of the mixing and dispersing tank 92. The diluter 90 is mounted on a frame outside the mixing and dispersing tank 92. The atomizer 91 is connected between the diluter 90 and the mixing and dispersing tank. The mixing and dispersing tank 92 is provided with a raw material inlet and a solidified material outlet. The phosphogypsum raw material crusher 10 is connected to the raw material inlet, and the solidified material outlet is located at the feed end of the phosphogypsum solidified material silo 8. After the raw phosphogypsum is crushed to the target particle size, it enters the mixing and dispersing tank 92. A curing agent of 0.3% to 1% is required to stabilize harmful substances in the phosphogypsum and improve its water stability. Therefore, the curing agent is sprayed into the mixing and dispersing tank using the atomizer 91. Because the curing agent content is low and difficult to mix evenly, the curing agent needs to be diluted first. The curing agent dilution liquid is added to the mixing and dispersion tank in the form of a spray. After mixing evenly, the moisture content of the phosphogypsum is controlled to below 15%. A dryer is used to control the moisture content before it can be used as the raw material for the next pavement base material.

[0037] In this embodiment, the phosphogypsum curing agent composition is as described in application publication number CN 117303846 A, namely, the phosphogypsum curing agent composition is: 65.02-91.23% phosphogypsum slag cement, 5.47-16.25% admixtures, 0.55-3.84% modifier, and 2.74-15.6% anti-seepage agent. The admixtures include adsorbents, precipitants, coagulants, and complexing agents; the modifiers include surfactants and hydrophobic modifiers. When using the curing agent, a propeller-type stirring blade and a blade drive are installed in the diluter. The blade drive is mounted on the top of the diluter, and the propeller-type stirring blade shaft end is connected to the blade drive, with the stirring end extending into the diluter. The curing agent is diluted with water and then poured into the diluter. Since the curing agent is a low-viscosity fluid with a viscosity of less than 2 Pa·s, it is continuously stirred by the propeller-type stirring blade to achieve uniform mixing before being supplied to the atomizer.

[0038] In this embodiment, the atomizer 91 includes an ultrasonic atomizer body 91-1, an atomizer tube 91-2, and an atomizer nozzle 91-3. The fluid inlet of the ultrasonic atomizer body 91-1 is connected to the diluter 90, and the fluid channel of the ultrasonic atomizer body is connected to the atomizer tube 91-2. The atomizer tubes 91-2 are provided in two or more groups and are evenly arranged along the length direction of the stirring and dispersing tank. The number of atomizer tubes is determined by the volume of the stirring and dispersing tank. The atomizer nozzle is fixed at the front end of the atomizer tube and placed in the stirring and dispersing tank.

[0039] The atomization rate is related to the volume of the stirring and dispersing tank. The phosphogypsum solidification and air-drying machine is calculated based on a stirring efficiency of 1t / h and a curing agent dosage of 0.5%. The curing agent spray flow rate should be 80ml / min, and the spray is diluted with water at a ratio of 1:5. If 10 nozzles are installed, the target flow rate of each nozzle is about 40ml / min.

[0040] Considering the atomization flow rate and particle size requirements of this project, the atomized particles need to be below 10μm for industrial production, and an atomization speed of about 40ml / min is required. Therefore, the ultrasonic atomization principle is used to atomize the curing agent liquid in this project. The maximum viscosity of the material that can be effectively processed by ultrasound is 4000 cps, and the upper temperature limit is about 65°C.

[0041] In this embodiment, to stabilize and detoxify the phosphogypsum, a diluted curing agent spray is uniformly dispersed within the phosphogypsum powder, ensuring maximum contact between the phosphogypsum powder and the curing agent, thereby completing the required mixing and reaction process in the shortest possible time. A helical ribbon stirring blade 92-2 is mounted on the stirring shaft 92-1 within the stirring and dispersing tank 92. The helical ribbon stirring blade is bolted to the stirring arm, facilitating replacement and adjustment of the stirring blade or stirring arm after wear and tear. As the helical ribbon stirring shaft rotates, its internal rotating shaft rotates axially, thereby driving the stirring blade to rotate, stirring and mixing the powder and liquid within the container. As the rotating shaft rotates, the material also rotates around the rotating shaft within the container, forming a vortex. Because the material rotates in the same direction as the rotating shaft, this results in localized material misalignment and reduced friction, resulting in uniform mixing of the localized materials, making it suitable for the curing and stirring of phosphogypsum.

[0042] The structural design of the mixing and dispersing tank 92, as shown by the vector diagram and streamlines, shows that the material is fully agitated, moving in the direction of rotation. The mixture also rotates with the main flow after entering the nozzle. The two-phase cloud diagram shows that the two materials are distributed relatively evenly overall, but there are localized areas of high concentration near the blades. In future implementation, in-tank sampling will be used to achieve a mixing uniformity coefficient of variation (CV) of ≤5% for parameter adjustment.

[0043] The dryer 90 is mounted on the outer periphery of the mixing and dispersing tank 92. Dryer 90 utilizes a conduit-type dehydration system. Because dihydrate phosphogypsum gradually converts to β-hemihydrate phosphogypsum after reaching 120°C, a dehydrator capable of controlling the dehydration temperature below 120°C is required. Furthermore, to conserve energy and reduce carbon emissions, indirect heating through heat conduction is preferred. The drying process requires little or no air to remove moisture, significantly reducing heat loss due to airflow and improving heat utilization. Furthermore, to achieve integrated curing and dehydration, the dehydration system needs to be integrated into the curing machine. Therefore, a heat-conducting dehydration system is selected, with a dehydration temperature range of 50°C to 300°C.

[0044] Furthermore, the solidified phosphogypsum silo 8 comprises a funnel-shaped silo body and a rotary vibrating arch-breaking assembly. The funnel-shaped silo body comprises an outer shell and an inner shell, the inner shell having an inverted trapezoidal cross-section. The rotary vibrating arch-breaking assembly is mounted at the discharge port of the inner shell to control the vibrating arch-breaking discharge of the solidified phosphogypsum. The specific structure of the solidified phosphogypsum silo has been previously patented; specifically, reference is made to a rotary vibrating arch-breaking device for the silo under publication number CN 117228174 A.

[0045] In this embodiment, the aggregate silo 1 is calculated based on the capacity of the phosphogypsum solidified body silo 8 and the phosphogypsum solidification and air-drying integrated machine 9. Four groups of aggregate silos 1 are arranged side by side in the funnel-shaped silo body. The starting end of the conveyor is placed below the discharge port of the funnel-shaped silo body and extends along the setting direction of the aggregate silo, extending all the way to the feed end of the mixing machine.

[0046] Furthermore, the mixing mixer 5 comprises two stacked mixing tanks. The second-layer admixture doser 11 and water reservoir 7 are connected to the upper mixing tank. The end of the conveyor 4 is connected to the upper mixing tank 5-1, and the outlet of the lower mixing tank 5-2 is connected to the discharge silo. This double mixing process ensures thorough mixing of the solidified phosphogypsum with building aggregates, cement, and other materials. However, the addition of water during mixing can cause phosphogypsum to adhere to the mixing tank walls, resulting in uneven mixing. The mixing shaft can also be modified to be movable, and a speed-changing mechanism can be used to control the forward and reverse motion of the unidirectional motor. This ensures stable control and output of mechanical motion. The spacing between the stirring blades and the mixing tank walls can be flexibly adjusted to accommodate varying material particle size requirements and mixing needs. Example 2

[0047] Based on the above phosphogypsum harmless treatment device, a phosphogypsum harmless treatment process is generated, which includes the following steps: S1. Phosphogypsum should be thoroughly aired and crushed before construction. The moisture content of the phosphogypsum should be controlled to ≤ 15%, preferably ≤ 12%, and the particle size should be ≤ 5mm, preferably ≤ 3mm. Before mixing, test the moisture content of the phosphogypsum and adjust the mixer ratio based on the test results. When the moisture content of the phosphogypsum raw material is less than 15%, use a hammer crusher with a discharge particle size of 0.1-2mm. When the moisture content of the phosphogypsum raw material is greater than 15%, use a hammer crusher that crushes sticky materials with a discharge particle size of 0.1-5mm. S2. Using a crusher to crush the phosphogypsum raw material and transport it to a phosphogypsum solidification and air-drying machine; S3. Add 5 to 10 parts of water to each part of the curing agent liquid and dilute it in an admixture doser. After dilution, supply the diluter. Turn on the propeller stirring blade to stir during dilution. Then, turn on the atomizer to spray the curing agent into the stirring and dispersing tank. The atomized particle size is less than 10 microns and the atomization rate is 40 ml / min. The atomization spraying and stirring and dispersing are performed simultaneously. After the phosphogypsum is uniformly solidified, turn on the dryer to dry it. The drying temperature range is 50° C. to 300° C. After drying, a solidified phosphogypsum body with a moisture content of less than 15% is formed. S4. The upper cover of the stirring and dispersing tank can be opened. After mixing for a certain period of time, the cover can be opened to take samples from various places. After the requirements are met, the stirring and dispersing tank will discharge the phosphogypsum solidified body and input it into the phosphogypsum solidified body silo; S5. Simultaneously open the phosphogypsum solidified body silo and the aggregate silo, the aggregate silo is loaded with construction aggregates, and discharge the phosphogypsum solidified body and construction aggregates onto a conveyor according to metering. The conveyor transports the mixed materials to the mixing mixer; S6. The powder silo and powder mixer are operated simultaneously. Cement and other powder materials are mixed according to the measurement and then fed into the mixer. The phosphogypsum and cement silos should be kept airtight and equipped with mechanical and vibrating arch-breaking devices to prevent arching. A metering device with an accuracy of ±0.5% should also be used. S7. All materials, admixtures and water are mixed and passed through upper and lower mixing tanks to be fully mixed. After mixing, the phosphogypsum-based new material is obtained, and the phosphogypsum-based new material is discharged into the unloading bin.

[0048] It should be noted that when mixing, if the ambient temperature is higher than 30℃, the temperature of the mixing equipment should not be higher than 70℃. When the ambient temperature is lower than 15℃, the temperature of the mixing equipment should not be lower than 10℃. If the temperature is too high or too low, temperature adjustment measures should be taken. Example 3

[0049] The application of the new phosphogypsum-based material obtained by the harmless treatment process in roadbed construction includes the following steps: S1. Using a transport vehicle with a short bed, the transport vehicle loads the harmless phosphogypsum-based new material from a discharge bin. During the loading process, the segregation of the mixture should be reduced by adjusting the position of the carriage.

[0050] S2. Use tarpaulin to cover the material during transportation to reduce water evaporation and mixing leakage. When the ambient temperature is higher than 30°C, the time from mixing to transportation to on-site paving should not exceed 2 hours, and if it exceeds 3 hours, it should be disposed of as waste. When the ambient temperature is lower than 30°C and higher than 15°C, the time from mixing to transportation to on-site paving should not exceed 3 hours, and if it exceeds 4 hours, it should be disposed of as waste. When the ambient temperature is lower than 15°C, the time from mixing to transportation to on-site paving should exceed 4 hours, and if it exceeds 5 hours, it should be disposed of as waste.

[0051] S3. During unloading, the phosphogypsum mixture has a high moisture content and is easily adhered to the side wall of the transport vehicle, making it difficult to unload onto the paver or subbase. It is advisable to use a transport vehicle with a short bed to increase the unloading angle as much as possible. If conditions permit, a vibrator can be installed on the transport vehicle to assist in unloading.

[0052] S4. When paving, adopt a two-layer continuous paving construction method. Each layer is equipped with independent paving and rolling equipment. Do not use one set of equipment to construct the upper and lower structural layers back and forth. Ensure sufficient paving thickness (for example, the maximum paving thickness of persulfate gypsum stabilized artificial aggregate mixture should not exceed 200mm). After rolling and forming, the paving thickness of each layer should be no less than 160mm. During the paving process, keep the paver speed controlled at 1.0-3.0m / min; When paving the mixture, it should be kept continuous. If the interruption time exceeds 2 hours for some reason, transverse joints should be set. Longitudinal joints should be avoided during paving. When paving in two sections, the longitudinal joints should be rolled more tightly. If longitudinal joints exist, they should be connected vertically. Slanting is strictly prohibited. When using multiple pavers for paving, the models and wear levels of the pavers should be the same. During construction, the front and rear spacing of the pavers should not be greater than 10m, and adjacent construction sections should overlap by 30cm-40cm in the longitudinal direction. When the width of the stabilized layer is 11-12m, the length of each continuous operation section should be 300m. When the width of the stabilized layer is greater than 12m, the length of the operation section should be shortened accordingly. The following factors should be comprehensively considered to reasonably determine the length of the daily construction operation section. 8) A dedicated person should be assigned behind the paver to eliminate aggregate segregation and phosphogypsum agglomeration, promptly remove segregated or agglomerated areas, and fill them with good mixed materials. The following factors should be comprehensively considered to reasonably determine the length of the daily construction work section. A dedicated person should be assigned behind the paver to eliminate aggregate segregation and phosphogypsum agglomeration, promptly remove segregated or agglomerated areas, and fill them with good mixture.

[0053] S5. When rolling, compaction should be carried out in the order of steady pressure - strong vibration - weak vibration - steady pressure, and the compaction direction should be from the outside first to the inside. A dedicated person should be assigned to direct the compaction to prevent leakage and wheel marks. If soft and elastic phenomena occur, the mixed material in that part should be dug out in time and replaced with roadbed material with a moisture content that meets the design requirements for rolling. During hot construction, if the roadbed material becomes loose or shifts during rolling, it should be moistened with water mist and stirred evenly, adjusted to the factory moisture content, and then compacted; When rolling, it is advisable to set up and fix the side formwork. Small rollers and flat plate compactors should be used for initial compaction within 30 cm of facilities such as inspection wells and curbstones, and near the formwork on both sides of the roadbed, and then double steel wheel rollers and rubber wheel rollers should be used for compaction.

[0054] S6. During curing, after the phosphogypsum stabilization layer is rolled and passed the compaction inspection, it shall be covered and cured within 2 hours. The curing time is 7 days. When the average daily temperature is below 10℃, in rainy season and other unfavorable weather conditions, the curing time shall be extended to 14 days. The total curing period should be extended to 2 days before the start of the upper layer construction. Except for sprinkler trucks and small commuter vehicles, no vehicles are allowed to pass during this period. Tracked engineering vehicles are strictly prohibited from pressing directly. Ensure that the stabilization material layer is thermally insulated and moisturized. When the climate is hot and dry, cooling work should be done. If necessary, the film can be temporarily lifted and covered, and water can be sprinkled on the geotextile for cooling. Necessary insulation measures should be taken during the construction period in winter.

[0055] Supplementary explanation: In step S4, the paving equipment requirements are as follows: 1) A crawler-type hydraulic fully automatic auxiliary spreading machine should be selected, equipped with an automatic leveling system and measures to prevent material segregation. 2) A reverse blade should be installed in the middle of the spiral spreader to reduce longitudinal segregation. The spiral spreader should be equipped with a rubber front baffle to reduce vertical segregation. 3) When paving the persulfate gypsum stabilized artificial aggregate mixture, a rubber baffle should be installed in front of the paver scraper (including the widened side plate). The height of the bottom of the rubber baffle from the top surface of the underlying layer should not exceed 10mm. 4) During the paving process, the vibrator and rammer must be turned on for the paver. The vibration frequency of the vibrator shall not be lower than 30Ihz, the impact frequency of the rammer shall not be lower than 20Hz, and the stroke shall not be lower than 6mm.

[0056] In step S6, the curing can be carried out by using film covering, impermeable geotextile, wet sand, asphalt emulsion or watering with a sprinkler truck. The requirements for watering curing are: the number of watering times per day should be determined according to the climate, and the surface of the stabilizing material should always be kept moist; Film covering and curing: Before covering the film, the surface moisture of the base layer stabilized by the thiophosphate gypsum cementitious material should be observed and kept moist. The base layer should not be frequently placed in a dry-wet cycle. The film can be opened only after curing for 1 to 2 days before the construction of the upper structural layer. Geotextile health care: It is advisable to use a permeable geotextile to cover the entire cross-section of the stabilizing material layer. After laying the geotextile, pay attention to watering. The number of watering times per day should be determined according to the climate. Take care to prevent the geotextile from being damaged.

[0057] The above describes in detail the harmless treatment device, treatment process, and application of phosphogypsum provided by the present invention. The description of the specific embodiments is intended only to facilitate understanding of the method and core concept of the present invention. It should be noted that the present invention is applicable not only to road materials but also to various fields such as underground filling, mine backfilling, and site leveling. Those skilled in the art will appreciate that improvements and modifications to the present invention can be made without departing from the principles of the present invention, and such improvements and modifications fall within the scope of protection of the claims.

Claims

1. A harmless treatment device for phosphogypsum, comprising an aggregate silo, a powder silo, a powder mixer, a conveyor, a mixer, a discharge silo, and a water reservoir, wherein the conveyor is connected to the discharge end of the aggregate silo and the feed end of the mixer, the powder silo is connected to the powder mixer, the powder mixer is connected to the feed end of the mixer, the discharge silo is connected to the discharge end of the mixer, and the water reservoir is connected to the mixer. It is characterized in that The invention also includes a phosphogypsum solidified body silo located at the upstream end of the aggregate silo, a phosphogypsum solidified air-drying integrated machine connected to the phosphogypsum solidified body silo and located at the upstream end thereof, and a phosphogypsum raw material crusher located at the upstream end of the phosphogypsum solidified air-drying integrated machine. The phosphogypsum solidified body is harmless phosphogypsum formed by the thorough mixing reaction of phosphogypsum and a curing agent. The phosphogypsum solidification and air-drying integrated machine mainly consists of a diluter, an atomizer, a stirring and dispersing tank, and a dryer, and is mainly used for harmless treatment of phosphogypsum. The dryer is sleeved on the outer periphery of the stirring and dispersing tank, the diluter is installed on the frame outside the stirring and dispersing tank, the atomizer is connected between the diluter and the stirring and dispersing tank, and the stirring and dispersing tank is provided with a raw material inlet and a solidified body outlet. The phosphogypsum raw material crusher is connected to the raw material inlet, and the solidified body outlet is placed at the feed end of the phosphogypsum solidified body silo. The phosphogypsum curing and air-drying machine is also connected to an admixture dosing machine for filling the phosphogypsum curing agent and supplying it to the diluter.

2. The harmless treatment device for phosphogypsum according to claim 1, characterized in that: The phosphogypsum raw material crusher adopts a hammer crusher or a hammer crusher for crushing sticky materials.

3. The harmless treatment device for phosphogypsum according to claim 1, characterized in that: A propulsion stirring blade and a blade drive are installed in the diluter. The blade drive is installed on the top of the diluter. The shaft end of the propulsion stirring blade is connected to the blade drive, and the stirring end is deep into the diluter.

4. The harmless treatment device for phosphogypsum according to claim 3, characterized in that: The atomizer includes an ultrasonic atomizer body, an atomizer tube, and an atomizer nozzle. The fluid inlet of the ultrasonic atomizer body is connected to the diluter, the fluid channel of the ultrasonic atomizer body is connected to the atomizer tube, and the atomizer tubes are provided in two or more groups and are evenly arranged along the length direction of the stirring and dispersing tank. The atomizer nozzle is fixed at the front end of the atomizer tube and placed in the stirring and dispersing tank.

5. The harmless treatment device for phosphogypsum according to claim 4, characterized in that: A spiral ribbon stirring blade is installed on the stirring shaft in the stirring and dispersing tank.

6. The harmless treatment device for phosphogypsum according to claim 1, characterized in that: The phosphogypsum solidified body silo includes a funnel-shaped silo body and a rotary vibration arch-breaking component. The funnel-shaped silo body is divided into an outer shell layer and an inner shell layer. The cross-section of the inner shell layer is an inverted trapezoidal shape. The rotary vibration arch-breaking component is installed at the discharge port of the inner shell layer to control the vibration arch-breaking discharge of the phosphogypsum solidified body.

7. The harmless treatment device for phosphogypsum according to claim 6, characterized in that: There is at least one group of aggregate silos, which are arranged side by side in the funnel-shaped silo body. The starting end of the conveyor is placed below the discharge port of the funnel-shaped silo body and extends along the setting direction of the aggregate silo to the feed end of the mixer.

8. The harmless treatment device for phosphogypsum according to claim 7, characterized in that: The mixing mixer consists of two groups of mixing cylinders stacked up and down, the additive dosing machine and the water reservoir are connected to the upper mixing cylinder, the end of the conveyor is connected to the upper mixing cylinder, and the outlet of the lower mixing cylinder is connected to the discharge bin.

9. A harmless treatment process for phosphogypsum, characterized by: Contains the following steps, S1. Test the moisture content of the phosphogypsum raw material. When the moisture content is less than 15%, use a hammer crusher with a discharge particle size of 0.1-2mm. When the moisture content of the phosphogypsum raw material is greater than 15%, use a hammer crusher that can crush sticky materials with a discharge particle size of 0.1-5mm. S2. Use a crusher to crush the phosphogypsum raw materials and transport them to a phosphogypsum solidification and air-drying machine for harmless treatment; S3. Add 5 to 10 parts of water to each part of the curing agent liquid and dilute it in an admixture doser. After dilution, supply the diluter. Turn on the propeller stirring blade to stir during dilution. Then, turn on the atomizer to spray the curing agent into the stirring and dispersing tank. The atomized particle size is less than 10 microns and the atomization rate is 40 ml / min. The atomization spraying and stirring and dispersing are performed simultaneously. After the phosphogypsum is detoxified, turn on the dryer to dry it. The drying temperature range is 50° C. to 300° C. After drying, a solidified phosphogypsum with a moisture content of less than 15% is formed. S4, the mixing and dispersing tank discharges the phosphogypsum solidified body and inputs it into the phosphogypsum solidified body silo, S5. Open the phosphogypsum solidified body silo and the aggregate silo at the same time. The aggregate silo is loaded with building aggregates. Put the phosphogypsum solidified body and building aggregates on the conveyor according to the measurement. The conveyor transports the mixed materials to the mixing mixer. S6, the powder silo and powder mixer are running at the same time, mixing cement and other powders according to the measurement and then feeding them into the mixer. S7. All materials, admixtures and water are mixed and passed through upper and lower mixing tanks to be fully mixed. After mixing, the phosphogypsum-based new material is obtained, and the phosphogypsum-based new material is discharged into the unloading bin.

10. Application of the phosphogypsum-based new material obtained by the harmless treatment process according to claims 1 to 9 in roadbed construction, wherein the application steps include: S1. Use a short truck to load the harmless phosphogypsum-based new materials from the unloading bin. S2. During transportation, tarpaulin should be used to cover the material. When the ambient temperature is higher than 30°C, the time from mixing to transportation to on-site paving should not exceed 2 hours. If it exceeds 3 hours, it should be disposed of as waste. When the ambient temperature is lower than 30°C and higher than 15°C, the time from mixing to transportation to on-site paving should not exceed 3 hours. When the ambient temperature is lower than 15°C, the time from mixing to transportation to on-site paving should exceed 4 hours. S3. When unloading, the transport vehicle increases the unloading angle and is equipped with a vibrator to assist in unloading. S4. When paving, adopt the method of two-layer continuous paving construction, and equip each layer with independent paving and rolling equipment. Ensure sufficient paving thickness. After rolling and forming, the paving thickness of each layer should be no less than 160mm. During the paving process, keep the paver speed controlled at 1.0-3.0m / min. Maintain transverse joints during paving. During construction, the distance between the front and rear pavers should not be greater than 10m, and the adjacent construction sections should overlap by 30cm to 40cm in the longitudinal direction. When the width of the stable layer is 11~12m, the length of each flow operation section should be 300m; when the width of the stable layer is greater than 12m, the length of the operation section should be shortened accordingly. S5. When rolling, compact according to the process of steady pressure - strong vibration - weak vibration - steady pressure, and compact according to the compaction direction of first the outside and then the inside. During hot construction, if the roadbed material becomes loose or moves during the rolling process, it should be moistened with water mist and stirred evenly, and adjusted to the moisture content of the factory before compaction. S6. During curing, after the phosphogypsum stabilization layer is compacted and passes the compaction inspection, it shall be covered and cured within 2 hours. The curing time is 7 to 14 days.

Images