Processes and equipment for solidifying and resource-based treatment of hazardous impurities in industrial solid waste phosphogypsum

Abstract

This invention provides a process and equipment for the solidification and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum, relating to the field of solid waste treatment technology, including the following steps: Step S1, Raw material composition: Main components: Ca(OH)2 (40-60wt%), Al(OH)3 (20-30wt%); Rare earth source: one or more of La2(CO3)3, Ce(NO3)3, NdCl3, Y2O3 (5-15wt%); Dispersant: Ethanol, Polyethylene glycol (PEG-400) (1-5wt%). This scheme ultimately achieves LDH adsorption of PO4 in the solidification stage. 3‑ A stable interlayer structure is formed. The high temperature during the calcination stage causes REPO4 nanoparticles to embed into the gypsum lattice, which enhances mechanical properties and effectively solidifies soluble phosphorus, fluorine and heavy metal impurities in phosphogypsum, thus achieving its harmless treatment and high-value resource utilization.

Description

Technical Field

[0001] This invention relates to the field of solid waste treatment, and in particular to a process and equipment for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum. Background Technology

[0002] Phosphogypsum is a large industrial solid waste generated during the wet process of phosphoric acid production. The soluble phosphates in it can cause phosphorus enrichment in the soil. During the storage process, rainwater leaches phosphogypsum, producing acidic leachate water that carries a large amount of phosphates, fluorides, and heavy metal ions into groundwater or surface water, leading to water quality deterioration. Resource-based treatment of phosphogypsum is the fundamental way to solve its environmental pollution problem.

[0003] In related technologies, phosphogypsum contains soluble phosphorus, fluorine, and heavy metal impurities, which can pollute the environment. This problem can be effectively solved through harmless treatment and high-value resource utilization. However, existing treatment technologies, such as physical separation methods involving washing and flotation, consume large amounts of water and achieve a soluble phosphorus recovery rate of less than 50%. Chemical solidification methods, using lime neutralization and phosphate precipitants, involve costly additives and poor long-term stability, with phosphorus leaching rates rebounding to 50% within three years. Furthermore, when utilizing these materials for resource utilization, product strength decreases, market acceptance is low, and it is difficult to achieve a synergistic effect of harmless treatment and high-value resource utilization.

[0004] Therefore, it is necessary to provide processes and equipment for the solidification and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a process and equipment for solidifying and recycling harmful impurities in industrial solid waste phosphogypsum, which solves the problem of defects in existing phosphogypsum recycling technologies in related technologies.

[0006] To solve the above-mentioned technical problems, the process for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum provided by the present invention includes the following steps;

[0007] Step S1, Raw material composition:

[0008] Main components: Ca(OH)2 (40-60wt%), Al(OH)3 (20-30wt%);

[0009] Rare earth source: one or more of La2(CO3)3, Ce(NO3)3, NdCl3, and Y2O3 (5-15wt%);

[0010] Dispersant: Ethanol, polyethylene glycol (PEG-400) (1-5wt%);

[0011] Step S2, Mechanochemical Stepwise Ball Milling:

[0012] Raw material pretreatment: rare earth oxides (such as Y2O3) are premixed with 5% citric acid solution;

[0013] Primary ball milling: Ca(OH)2 and Al(OH)2 are added in proportion and dry ball milling is used to construct the Ca-Al LDH matrix;

[0014] Rare earth doping: Adding rare earth salts such as La, Ce, and Nd to control the RE:Ca:Al molar ratio (0.5-2:4-6:1-3).

[0015] Secondary ball milling: Increasing the rotational speed triggers a solid-phase reaction, promoting RE 3+ Embedded LDH layer;

[0016] Dispersant enhancement: Add ethanol / PEG-400 (1-5wt%) and continue ball milling to improve material dispersibility;

[0017] Product: Ca / Al / RE LDH;

[0018] Step S3, application of phosphogypsum curing:

[0019] Phosphogypsum raw material crushing and screening: Powder the phosphogypsum to 80-120 mesh;

[0020] Mixed curing: Add LDH curing agent at a mass ratio of 3-10%, add water to adjust the slurry to a solid content of 60%, stir at 200 rpm, and react for 2-4 hours. The dual effects of LDH adsorption and REPO4 precipitation are achieved.

[0021] Calcination for resource utilization: After solidification, the material is calcined at 150-180℃ for 1.5-2 hours to produce β-hemihydrate gypsum with a compressive strength ≥10MPa.

[0022] Preferably, the raw material pretreatment acid activation time is 15 min, the ball milling speed is 200 rpm to break Y2O3 agglomeration and improve reaction activity, the primary ball milling speed is 300-400 rpm, and the time is 30-40 min. The rare earth doping adopts batch feeding, first adding La / Ce, then adding Nd / Y.

[0023] Preferably, the secondary ball milling speed is 500-600 rpm, the time is 40-60 min, the mechanical force induces ion replacement, and the dispersant strengthening time is 20-30 min.

[0024] Equipment for solidifying and recycling harmful impurities in industrial solid waste phosphogypsum, including a treatment vessel, a sealing cover, a drive mechanism, an addition mechanism, and an air intake mechanism;

[0025] The driving mechanism includes a rotating shaft that is vertically rotatably connected to the inside of the sealing cover. A connecting frame is fixed on the circumferential side of the rotating shaft. A rotating ring is fixed on the surface of the connecting frame. Two sets of teeth are fixed on the circumferential side of the rotating ring.

[0026] The adding mechanism includes a mounting plate fixed to the inner wall of the processing vessel. A swing frame is rotatably connected to the top of the mounting plate. A first rotating shaft is vertically rotatably connected to the inner side of the mounting plate. A rotating gear is fixed to the bottom end of the first rotating shaft. A first drive frame is fixed to the top end of the first rotating shaft. The peripheral side of the top of the first drive frame is located inside the swing frame. A mounting bracket is fixed to the top of the mounting plate. A dispensing tube is provided inside the mounting bracket. The adding mechanism is arranged in a circular array of four sets.

[0027] Preferably, the air intake mechanism includes a cam with a keyway connected to the surface of the rotating shaft, two support frames are fixedly provided on the top of the sealing cover, an air cylinder is provided on the inner side of each of the two support frames, a sliding bracket is slidably connected on the inner side of each of the two air cylinders, a piston is fixedly provided at one of the two sliding brackets at their opposite ends, a rotating wheel is rotatably connected on the inner side of the opposite side of each of the two sliding brackets, the two rotating wheels are in contact with the peripheral surface of the cam, and a spring is sleeved on the surface of each of the two sliding brackets.

[0028] Preferably, the sealing cap is fixed to the top of the processing vessel, and each of the two air cylinders has an air outlet pipe connected to one side of the cylinders that are separated from each other. The two air outlet pipes are connected to four delivery pipes, and each of the two air cylinders has an air extraction pipe connected to its front side.

[0029] Preferably, a water filling mechanism is vertically rotatably connected to the inner side of the mounting plate. The water filling mechanism includes a second rotating shaft vertically rotatably connected to the inside of the mounting plate. A rotating seat is fixed at the bottom end of the second rotating shaft. A nozzle is provided on the inner side of the rotating seat. A second drive frame is fixed at the top end of the second rotating shaft. The peripheral side of the top of the second drive frame is located inside the swing frame.

[0030] Preferably, the bottom of the sealing cover is rotatably connected to a feeding mechanism, the feeding mechanism including a rotating rod rotatably connected to the bottom of the sealing cover, a feeding disc fixed on the surface of the rotating rod, a feeding pipe vertically arranged on the inner side of the sealing cover, pulleys fixed on the circumferential sides of the rotating rod and the rotating shaft, belts sleeved on the surfaces of the two pulleys, a protective cover fixed on the top of the sealing cover, a hopper fixed on the top of the protective cover, and the feeding pipe communicating with the hopper.

[0031] Preferably, a stirring mechanism is fixedly provided on the surface of the rotating shaft. The stirring mechanism includes two connecting members fixedly provided on the surface of the rotating shaft. A stirring paddle and a scraper are fixedly provided on the surface of the two connecting members. A drive motor for driving the rotating shaft to rotate is provided on the top of the protective cover.

[0032] Preferably, a support bracket is provided on the peripheral side of the processing vessel, a first connecting plate is fixedly provided on the top of the support bracket, a second connecting plate is fixedly provided on the inner side of the support bracket, the first connecting plate and the second connecting plate are fixedly connected to the peripheral side of the processing vessel, and a discharge pipe is connected to the bottom of the processing vessel.

[0033] Compared with related technologies, the process for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum provided by this invention has the following beneficial effects:

[0034] High-energy ball milling induces solid-phase reactions, avoiding wastewater generation in solution synthesis. Mixing rare earth elements adjusts the charge density of the LDH layers, enhancing the simultaneous adsorption capacity for multi-anionic impurities. Primary ball milling forms a porous Ca-Al LDH matrix, while secondary ball milling forces the RE... 3+ Interlayer insertion and gradient addition of dispersant; dry ball milling for the first 60 minutes to ensure mechanical strength; addition of ethanol for the next 30 minutes to maintain material hardness above 4H while increasing porosity by 20%; LDH adsorbs PO4 during the curing stage. 3- A stable interlayer structure is formed. The high temperature during the calcination stage causes REPO4 nanoparticles to embed into the gypsum lattice, which enhances mechanical properties and effectively solidifies soluble phosphorus, fluorine and heavy metal impurities in phosphogypsum, thus achieving its harmless treatment and high-value resource utilization. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0036] Figure 1 The optimal structural schematic diagram provided for this invention;

[0037] Figure 2 This is a schematic diagram of the right view of the processing vessel provided by the present invention;

[0038] Figure 3 for Figure 1 The diagram shows a cross-sectional view of the processing vessel.

[0039] Figure 4 A schematic diagram of the driving mechanism, adding mechanism, and water adding mechanism provided by the present invention;

[0040] Figure 5 for Figure 4 The diagram shows the structure of the adding mechanism and the water adding mechanism;

[0041] Figure 6 A schematic diagram showing the state in which the rotating shaft provided by the present invention drives the rotating ring and the tooth assembly to rotate clockwise through the connecting frame;

[0042] Figure 7 This is a schematic diagram of the intake mechanism provided by the present invention;

[0043] Figure 8 for Figure 7 The diagram shows a structural schematic of the cross-sectional view of the air cylinder.

[0044] Figure 9 This is a schematic diagram showing the state of the rotating shaft driving the cam to rotate clockwise, as provided by the present invention.

[0045] Figure 10 This is a schematic diagram of the dispensing mechanism provided by the present invention;

[0046] Figure 11 for Figure 10 The diagram shows the structural schematic of the bottom view of the feeding tray.

[0047] Figure 12 This is a schematic diagram of the stirring mechanism provided by the present invention.

[0048] Explanation of icon numbers:

[0049] 1. Processing vessel; 2. Sealing cap;

[0050] 3. Drive mechanism; 31. Rotating shaft; 32. Connecting frame; 33. Rotating ring; 34. Gear assembly;

[0051] 4. Adding mechanism; 41. Mounting plate; 42. Swing frame; 43. First rotating shaft; 44. Rotating gear; 45. First drive frame; 46. Mounting bracket; 47. Dispensing tube;

[0052] 5. Intake mechanism; 51. Cam; 52. Support frame; 53. Air cylinder; 54. Sliding bracket; 55. Piston; 56. Rotary wheel; 57. Spring;

[0053] 6. Water filling mechanism; 61. Second rotating shaft; 62. Rotating seat; 63. Nozzle; 64. Second drive frame;

[0054] 7. Feeding mechanism; 71. Rotating rod; 72. Feeding tray; 73. Feeding pipe; 74. Pulley; 75. Belt; 76. Hopper;

[0055] 8. Protective cover;

[0056] 9. Stirring mechanism; 91. Connecting parts; 92. Stirring paddle; 93. Scraper; 94. Drive motor;

[0057] 10. Support bracket; 11. First connecting plate; 12. Second connecting plate; 13. Discharge pipe. Detailed Implementation

[0058] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0059] This invention provides a process for solidifying and recycling harmful impurities in industrial solid waste phosphogypsum.

[0060] First embodiment:

[0061] The process for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum includes the following steps;

[0062] Step S1, Raw material composition:

[0063] Main components: Ca(OH)2 (40-60wt%), Al(OH)3 (20-30wt%);

[0064] Rare earth source: one or more of La2(CO3)3, Ce(NO3)3, NdCl3, and Y2O3 (5-15wt%);

[0065] Dispersant: Ethanol, polyethylene glycol (PEG-400) (1-5wt%);

[0066] Step S2, Mechanochemical Stepwise Ball Milling:

[0067] Raw material pretreatment: rare earth oxides (such as Y2O3) are premixed with 5% citric acid solution;

[0068] Primary ball milling: Ca(OH)2 and Al(OH)2 are added in proportion and dry ball milling is used to construct the Ca-Al LDH matrix;

[0069] Rare earth doping: Adding rare earth salts such as La, Ce, and Nd to control the RE:Ca:Al molar ratio (0.5-2:4-6:1-3).

[0070] Secondary ball milling: Increasing the rotational speed triggers a solid-phase reaction, promoting RE 3+ Embedded LDH layer;

[0071] Dispersant enhancement: Add ethanol / PEG-400 (1-5wt%) and continue ball milling to improve material dispersibility;

[0072] Product: Ca / Al / RE LDH;

[0073] Step S3, application of phosphogypsum curing:

[0074] Phosphogypsum raw material crushing and screening: Powder the phosphogypsum to 80-120 mesh;

[0075] Mixed curing: Add LDH curing agent at a mass ratio of 3-10%, add water to adjust the slurry to a solid content of 60%, stir at 200 rpm, and react for 2-4 hours. The dual effects of LDH adsorption and REPO4 precipitation are achieved.

[0076] Calcination for resource utilization: After solidification, the material is calcined at 150-180℃ for 1.5-2 hours to produce β-hemihydrate gypsum with a compressive strength ≥10MPa.

[0077] The raw material pretreatment acid activation time is 15 min, and the ball milling speed is 200 rpm to break the Y2O3 agglomeration and improve the reaction activity. The primary ball milling speed is 300-400 rpm and the time is 30-40 min. The rare earth doping adopts batch feeding, first adding La / Ce, then adding Nd / Y.

[0078] The secondary ball milling speed is 500-600 rpm, the time is 40-60 min, mechanical force induces ion replacement, and the dispersant strengthening time is 20-30 min.

[0079] In this embodiment, high-energy ball milling induces a solid-phase reaction, avoiding wastewater generation in solution synthesis. Mixing rare earth elements adjusts the charge density of the LDH layers, enhancing the simultaneous adsorption capacity for multi-anionic impurities. Primary ball milling forms a porous Ca-AlLDH matrix, while secondary ball milling forces the RE... 3+ Interlayer insertion and gradient addition of dispersant; dry ball milling for the first 60 minutes to ensure mechanical strength; addition of ethanol for the next 30 minutes to maintain material hardness above 4H while increasing porosity by 20%; LDH adsorbs PO4 during the curing stage. 3- A stable interlayer structure is formed. The high temperature during the calcination stage causes REPO4 nanoparticles to embed into the gypsum lattice, which enhances mechanical properties and effectively solidifies soluble phosphorus, fluorine and heavy metal impurities in phosphogypsum, thus achieving its harmless treatment and high-value resource utilization.

[0080] The present invention also provides equipment for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum.

[0081] First embodiment:

[0082] Please see Figures 1 to 9 Equipment for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum, including a treatment vessel 1, a sealing cover 2, a drive mechanism 3, an addition mechanism 4, and an air intake mechanism 5.

[0083] The drive mechanism 3 includes a rotating shaft 31 that is vertically rotatably connected to the inside of the sealing cover 2. A connecting frame 32 is fixedly provided on the circumferential side of the rotating shaft 31. A rotating ring 33 is fixedly provided on the surface of the connecting frame 32. Two sets of teeth 34 are fixedly provided on the circumferential side of the rotating ring 33.

[0084] The adding mechanism 4 includes a mounting plate 41 fixed to the inner wall of the processing vessel 1. A swing frame 42 is rotatably connected to the top of the mounting plate 41. A first rotating shaft 43 is vertically rotatably connected to the inner side of the mounting plate 41. A rotating gear 44 is fixed to the bottom end of the first rotating shaft 43. A first drive frame 45 is fixed to the top end of the first rotating shaft 43. The peripheral side of the top of the first drive frame 45 is located inside the swing frame 42. A mounting bracket 46 is fixed to the top of the mounting plate 41. A dispensing tube 47 is provided inside the mounting bracket 46. The adding mechanism 4 is arranged in a circular array of four sets.

[0085] The air intake mechanism 5 includes a cam 51 with a keyway connected to the surface of the rotating shaft 31. Two support frames 52 are fixedly mounted on the top of the sealing cover 2. Air cylinders 53 are provided on the inner side of each of the two support frames 52. Sliding brackets 54 are slidably connected to the inner side of each of the two air cylinders 53. A piston 55 is fixedly mounted on one of the two sliding brackets 54 at the opposite end. A rotating wheel 56 is rotatably connected to the inner side of the opposite side of each of the two sliding brackets 54. The two rotating wheels 56 are in contact with the peripheral side of the cam 51. Springs 57 are sleeved on the surface of each of the two sliding brackets 54.

[0086] The sealing cap 2 is fixed to the top of the processing vessel 1. The two air cylinders 53 are connected to an air outlet pipe on opposite sides. The two air outlet pipes are connected to four delivery pipes 47. The front of the two air cylinders 53 is connected to an air extraction pipe.

[0087] Please combine Figures 4 to 6 Start the drive motor 94. The drive motor 94 rotates and drives the rotating shaft 31 to rotate clockwise. The clockwise rotation of the rotating shaft 31 drives the rotating ring 33 and the tooth set 34 to rotate clockwise through the connecting frame 32. When the two sets of tooth sets 34 come into contact with the two opposing rotating gears 44 and continue to rotate, the two rotating gears 44 rotate counterclockwise and drive the first drive frame 45 to rotate through the first rotating shaft 43. The rotation of the first drive frame 45 drives the two swing frames 42 to swing in opposite directions. The swing of the two swing frames 42 drives the two dispensing pipes 47 to swing, thereby dispensing LDH curing agent into the treatment vessel 1 in a swinging manner.

[0088] Preferably, the dispensing tube 47 is used to dispense LDH curing agent. The adding mechanisms 4 are arranged in pairs facing each other. When the rotating shaft 31 rotates one revolution, the two sets of adding mechanisms 4 are intermittently driven to perform oscillating dispensing work through the two tooth groups 34, thereby oscillating to add LDH curing agent at four different positions. When the two dispensing tubes 47 in each set of adding mechanisms 4 are working, the oscillation direction is opposite.

[0089] Please combine Figures 7 to 9 When the rotating shaft 31 rotates clockwise, it will simultaneously drive the cam 51 to rotate clockwise. When the protruding part of the cam 51 contacts the rotating wheel 56, it will push the sliding bracket 54 to slide inside the air cylinder 53 through the rotating wheel 56. The sliding bracket 54 will then drive the piston 55 to slide on the inner wall of the air cylinder 53, thereby delivering the gas through the air outlet pipe to the delivery pipe 47.

[0090] Preferably, each vent pipe is connected to a set of dispensing pipes 47 of the adding mechanism 4. The dispensing pipe 47 is provided with a bend position. After dispensing, the LDH curing agent will stay at the bend position. Then, the LDH curing agent will be blown into the processing vessel 1 by the airflow delivered by the vent pipe. One-way valves are provided on the surface of the vent pipe, the extraction pipe and the dispensing pipe 47.

[0091] Furthermore, when the rotating shaft 31 drives the cam 51 to rotate one revolution, it will drive the two air cylinders 53 to perform an air intake action once.

[0092] In this embodiment, when the rotating shaft 31 rotates clockwise, it drives the rotating ring 33 and the two sets of toothed teeth 34 to rotate clockwise through the connecting frame 32. The clockwise rotation of the two sets of toothed teeth 34 drives the two dispensing pipes 47 in each group of adding mechanisms 4 to swing in opposite directions. The rotation of the rotating shaft 31 also drives the cam 51 to rotate. The rotation of the cam 51 causes the two air cylinders 53 to deliver airflow to the dispensing pipes 47 in each group of adding mechanisms 4 through the air outlet pipe. The airflow is used to swing and blow the LDH curing agent in the dispensing pipe 47 into the processing vessel 1, which can make the curing agent more evenly dispersed, improve the mixing effect of the curing agent and phosphogypsum raw material, improve the curing efficiency of impurities, and fully disperse the curing agent and phosphogypsum raw material. The β-hemihydrate gypsum produced after calcination has stable compressive strength, which can meet the application standards of building materials and realize true high-value resource utilization.

[0093] Second embodiment:

[0094] Please see Figure 2 , Figure 5 , Figure 6 , Figure 9 and Figure 10A water filling mechanism 6 is vertically rotatably connected to the inner side of the mounting plate 41. The water filling mechanism 6 includes a second rotating shaft 61 vertically rotatably connected to the inside of the mounting plate 41. A rotating seat 62 is fixed at the bottom end of the second rotating shaft 61. A nozzle 63 is provided on the inner side of the rotating seat 62. A second drive frame 64 is fixed at the top end of the second rotating shaft 61. The peripheral side of the top of the second drive frame 64 is located inside the swing frame 42.

[0095] The bottom of the sealing cover 2 is rotatably connected to a feeding mechanism 7. The feeding mechanism 7 includes a rotating rod 71 rotatably connected to the bottom of the sealing cover 2. A feeding disc 72 is fixed on the surface of the rotating rod 71. A feeding tube 73 is vertically arranged on the inner side of the sealing cover 2. Pulleys 74 are fixed on the circumferential sides of the rotating rod 71 and the rotating shaft 31. A belt 75 is sleeved on the surface of the two pulleys 74. A protective cover 8 is fixed on the top of the sealing cover 2. A hopper 76 is fixed on the top of the protective cover 8. The feeding tube 73 is connected to the hopper 76.

[0096] Preferably, the feeding mechanism 7 is arranged in a ring array with two sets, which are used to add phosphogypsum raw materials to different positions of the processing vessel 1. The two feeding plates 72 are installed at opposite angles. When the two feeding plates 72 rotate, they will intermittently feed phosphogypsum raw materials into the processing vessel 1 through the two feeding pipes 73 in sequence.

[0097] Preferably, the surface of the feeding tray 72 is provided with a notch. When the notch of the feeding tray 72 coincides with the feeding pipe 73, the phosphogypsum raw material in the hopper 76 falls into the processing vessel 1.

[0098] Please combine Figure 5 and Figure 6 When the swing frame 42 rotates, it will drive the second drive frame 64 to rotate around the second rotating shaft 61. The rotation of the second drive frame 64 will drive the rotating seat 62 and the nozzle 63 to rotate through the second rotating shaft 61. When the swing frame 42 drives the dispensing pipe 47 to swing back and forth once to dispense LDH curing agent, the nozzle 63 will swing back and forth at the same time to spray water.

[0099] Please combine Figure 2 , Figure 9 and Figure 10 When the rotating shaft 31 rotates, it will simultaneously drive the two pulleys 74 on the surface to rotate. Through the belt 75 and the pulleys 74 on the surface of the rotating rod 71, it will simultaneously drive the two feeding discs 72 to rotate. Through the rotation of the two feeding discs 72, the two feeding pipes 73 will intermittently feed phosphogypsum raw materials into the processing vessel 1 from different positions.

[0100] In this embodiment, when the swing frame 42 drives the dispensing pipe 47 to swing back and forth to dispense the curing agent, it will simultaneously drive the second drive frame 64 to rotate, thereby causing the second rotating shaft 61 to drive the nozzle 63 to swing back and forth to spray water. The swing-type blowing and dispensing of the curing agent is synchronized with the swing-type spraying of water. At the same time, through the rotation of the two feeding discs 72, the two feeding pipes 73 are intermittently dispensing phosphogypsum raw materials into the treatment vessel 1 from different positions, so that the three are uniformly mixed in the vessel. The uniform mixing of phosphogypsum raw materials, curing agent and water can make the LDH curing agent play its role fully, avoid impurity residues caused by excessively high or low local curing agent concentration, and ensure that the leaching concentration of phosphorus, fluorine and heavy metals after curing is consistently lower than the national standard limit. At the same time, the uniform slurry results in more uniform crystal growth during subsequent low-temperature calcination, and the strength fluctuation of the produced β-hemihydrate gypsum is smaller, and the compressive strength is very stable, which can meet the quality requirements for use as a building material.

[0101] Third embodiment:

[0102] Please see Figure 1 , Figure 2 and Figure 12 A stirring mechanism 9 is fixedly provided on the surface of the rotating shaft 31. The stirring mechanism 9 includes two connecting parts 91 fixedly provided on the surface of the rotating shaft 31. A stirring paddle 92 and a scraper 93 are fixedly provided on the surface of the two connecting parts 91. A drive motor 94 for driving the rotating shaft 31 to rotate is provided on the top of the protective cover 8.

[0103] The processing vessel 1 is provided with a support bracket 10 on its peripheral side. A first connecting plate 11 is fixedly provided on the top of the support bracket 10, and a second connecting plate 12 is fixedly provided on the inner side of the support bracket 10. The first connecting plate 11 and the second connecting plate 12 are fixedly connected to the peripheral side of the processing vessel 1, and a discharge pipe 13 is connected to the bottom of the processing vessel 1.

[0104] Please combine Figure 12 Start the drive motor 94. The drive motor 94 rotates and drives the rotating shaft 31 to rotate clockwise. The clockwise rotation of the rotating shaft 31 drives the stirring paddle 92 to rotate through the connector 91, thereby stirring and mixing the phosphogypsum raw material, LDH curing agent and water that are added in sequence. When the rotating shaft 31 rotates, it also drives the two scraper plates 93 to rotate through the connector 91 to clean the inner wall of the treatment vessel 1.

[0105] In this embodiment, the rotation of the drive motor 94 drives the rotating shaft 31 to rotate clockwise. The clockwise rotation of the rotating shaft 31 drives the stirring paddle 92 to rotate through the connecting piece 91, thereby stirring and mixing the added phosphogypsum raw materials, LDH curing agent and water. This can quickly disperse and mix the newly added phosphogypsum raw materials, curing agent and water, avoiding problems such as local material agglomeration or uneven slurry concentration.

[0106] Please refer to the reference again. Figures 1 to 12 The working principle of the equipment for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum provided by the present invention is as follows:

[0107] Step S1: Start the drive motor 94. The drive motor 94 rotates, causing the rotating shaft 31 to rotate clockwise. The clockwise rotation of the rotating shaft 31 drives the stirring paddle 92 to rotate through the connecting piece 91.

[0108] In step S2, when the rotating shaft 31 rotates, it will simultaneously drive the two pulleys 74 on the surface to rotate. Through the belt 75 and the pulleys 74 on the surface of the rotating rod 71, it will simultaneously drive the two feeding discs 72 to rotate. Through the rotation of the two feeding discs 72, the two feeding pipes 73 will intermittently feed phosphogypsum raw materials into the processing vessel 1 from different positions.

[0109] In step S3, the clockwise rotation of the rotating shaft 31, through the connecting frame 32, will drive the rotating ring 33 and the toothed assembly 34 to rotate clockwise. When the two sets of toothed assemblies 34 come into contact with the two opposing rotating gears 44 and continue to rotate, the two rotating gears 44 will rotate counterclockwise, and through the first rotating shaft 43, drive the first drive frame 45 to rotate. The rotation of the first drive frame 45 will drive the two swing frames 42 to swing in opposite directions. The swing of the two swing frames 42 will then drive the two dispensing tubes 47 to swing, thereby dispensing LDH curing agent into the processing vessel 1 in a swinging manner.

[0110] In step S4, when the rotating shaft 31 rotates clockwise, it will simultaneously drive the cam 51 to rotate clockwise. When the protruding position of the cam 51 contacts the rotating wheel 56, it will push the sliding bracket 54 to slide inside the air cylinder 53 through the rotating wheel 56. The sliding bracket 54 will then drive the piston 55 to slide on the inner wall of the air cylinder 53, thereby delivering the gas through the outlet pipe to the delivery pipe 47, and delivering the LDH curing agent in the delivery pipe 47 into the processing vessel 1 through airflow oscillation.

[0111] In step S5, when the swing frame 42 rotates, it will drive the second drive frame 64 to rotate around the second rotating shaft 61. The rotation of the second drive frame 64 drives the rotating seat 62 and the nozzle 63 to rotate through the second rotating shaft 61. When the swing frame 42 drives the dispensing pipe 47 to swing back and forth once to dispense LDH curing agent, the nozzle 63 will swing back and forth to spray water at the same time. Through the rotation of the stirring paddle 92, the added phosphogypsum raw materials, curing agent and water can be quickly dispersed and mixed.

[0112] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A process for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum, characterized in that, Includes the following steps; Step S1, Raw material composition: Main components: Ca(OH)2 (40-60wt%), Al(OH)3 (20-30wt%); Rare earth source: one or more of La2(CO3)3, Ce(NO3)3, NdCl3, and Y2O3 (5-15wt%); Dispersant: Ethanol, polyethylene glycol (PEG-400) (1-5wt%); Step S2, Mechanochemical Stepwise Ball Milling: Raw material pretreatment: rare earth oxides (such as Y2O3) are premixed with 5% citric acid solution; Primary ball milling: Ca(OH)2 and Al(OH)2 are added in proportion and dry ball milling is used to construct the Ca-Al LDH matrix; Rare earth doping: Adding rare earth salts such as La, Ce, and Nd to control the RE:Ca:Al molar ratio (0.5-2:4-6:1-3). Secondary ball milling: Increasing the rotational speed triggers a solid-phase reaction, promoting RE 3+ Embedded LDH layer; Dispersant enhancement: Add ethanol / PEG-400 (1-5wt%) and continue ball milling to improve material dispersibility; Product: Ca / Al / RE LDH; Step S3, application of phosphogypsum curing: Phosphogypsum raw material crushing and screening: Powder the phosphogypsum to 80-120 mesh; Mixed curing: Add LDH curing agent at a mass ratio of 3-10%, add water to adjust the slurry to a solid content of 60%, stir at 200 rpm, and react for 2-4 hours. The dual effects of LDH adsorption and REPO4 precipitation are achieved. Calcination for resource utilization: After solidification, the material is calcined at 150-180℃ for 1.5-2 hours to produce β-hemihydrate gypsum with a compressive strength ≥10MPa.

2. The process for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum according to claim 1, characterized in that, The raw material pretreatment acid activation time is 15 min, and the ball milling speed is 200 rpm to break the Y2O3 agglomeration and improve the reaction activity. The primary ball milling speed is 300-400 rpm and the time is 30-40 min. The rare earth doping adopts batch feeding, first adding La / Ce, then adding Nd / Y.

3. The process for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum according to claim 1, characterized in that, The secondary ball milling speed is 500-600 rpm, the time is 40-60 min, mechanical force induces ion replacement, and the dispersant strengthening time is 20-30 min.

4. Equipment for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum, characterized in that, The resource recovery processing equipment is used in the resource recovery process as described in any one of claims 1-3, and includes a processing vessel, a sealing cap, a driving mechanism, an adding mechanism, and an air intake mechanism; The driving mechanism includes a rotating shaft that is vertically rotatably connected to the inside of the sealing cover. A connecting frame is fixed on the circumferential side of the rotating shaft. A rotating ring is fixed on the surface of the connecting frame. Two sets of teeth are fixed on the circumferential side of the rotating ring. The adding mechanism includes a mounting plate fixed to the inner wall of the processing vessel. A swing frame is rotatably connected to the top of the mounting plate. A first rotating shaft is vertically rotatably connected to the inner side of the mounting plate. A rotating gear is fixed to the bottom end of the first rotating shaft. A first drive frame is fixed to the top end of the first rotating shaft. The peripheral side of the top of the first drive frame is located inside the swing frame. A mounting bracket is fixed to the top of the mounting plate. A dispensing tube is provided inside the mounting bracket. The adding mechanism is arranged in a circular array of four sets.

5. The equipment for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum according to claim 4, characterized in that, The air intake mechanism includes a cam connected to the surface of the rotating shaft via a keyway. Two support frames are fixedly mounted on the top of the sealing cover. An air cylinder is provided on the inner side of each of the two support frames. A sliding bracket is slidably connected to the inner side of each of the two air cylinders. A piston is fixedly mounted on one of the two sliding brackets at their opposite ends. A rotating wheel is rotatably connected to the inner side of the opposite side of each of the two sliding brackets. The two rotating wheels are in contact with the peripheral surface of the cam. A spring is sleeved on the surface of each of the two sliding brackets.

6. The equipment for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum according to claim 5, characterized in that, The sealing cap is fixed to the top of the processing vessel. Each of the two air cylinders has an outlet pipe connected to one side of the cylinder. The two outlet pipes are connected to four delivery pipes. Each of the two air cylinders has an extraction pipe connected to its front side.

7. The equipment for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum according to claim 4, characterized in that, A water-filling mechanism is vertically rotatably connected to the inner side of the mounting plate. The water-filling mechanism includes a second rotating shaft vertically rotatably connected to the inside of the mounting plate. A rotating seat is fixed at the bottom end of the second rotating shaft. A nozzle is provided on the inner side of the rotating seat. A second drive frame is fixed at the top end of the second rotating shaft. The peripheral side of the top of the second drive frame is located inside the swing frame.

8. The equipment for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum according to claim 4, characterized in that, The bottom of the sealing cover is rotatably connected to a feeding mechanism. The feeding mechanism includes a rotating rod rotatably connected to the bottom of the sealing cover. A feeding disc is fixed on the surface of the rotating rod. A feeding pipe is vertically arranged on the inner side of the sealing cover. Pulleys are fixed on the circumferential sides of the rotating rod and the rotating shaft. A belt is fitted on the surface of the two pulleys. A protective cover is fixed on the top of the sealing cover. A hopper is fixed on the top of the protective cover. The feeding pipe is connected to the hopper.

9. The equipment for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum according to claim 8, characterized in that, A stirring mechanism is fixedly provided on the surface of the rotating shaft. The stirring mechanism includes two connecting parts fixedly provided on the surface of the rotating shaft. A stirring paddle and a scraper are fixedly provided on the surface of the two connecting parts. A drive motor for driving the rotating shaft to rotate is provided on the top of the protective cover.

10. The equipment for solidifying and resource-based treatment of harmful impurities in industrial solid waste phosphogypsum according to claim 4, characterized in that, The processing vessel is provided with a support bracket on its peripheral side. A first connecting plate is fixedly installed on the top of the support bracket, and a second connecting plate is fixedly installed on the inner side of the support bracket. The first connecting plate and the second connecting plate are fixedly connected to the peripheral side of the processing vessel, and a discharge pipe is connected to the bottom of the processing vessel.

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