Method for co-cementation of radionuclides by red mud-lithium slag and forming device

Abstract

This invention provides a method and apparatus for the co-solidification of radionuclides using red mud and lithium slag, relating to the field of radioactive pollution control. The method for co-solidifying radionuclides using red mud and lithium slag includes the following steps: S1, mixing dried red mud and lithium slag at a mass ratio of 60%~80% red mud and 20%~40% lithium slag, and adding 1%~5% (by mass of red mud) of a phosphate-based auxiliary solidifying agent to the mixture; S2, placing the dried red mud, lithium slag, and auxiliary solidifying agent in a ball mill. The method for co-solidifying radionuclides using red mud and lithium slag provided by this invention involves mixing red mud and lithium slag at a certain mass ratio and sintering at 1000℃ for 2 hours. Boron reacts fully with aluminum and silicon oxides in the red mud to form a three-dimensional network structure, reducing the leaching rates of uranium and thorium to below 0.05 Bq / L and 0.1 Bq / L, respectively, which is more than 99% lower than that of the original red mud. Compared with traditional technologies, this process reduces the sintering temperature to 1000℃ and achieves long-term stabilization of radionuclides solely through the synergistic reaction between red mud and lithium slag.

Description

Technical Field

[0001] This invention relates to the field of radioactive pollution control, and in particular to a method and molding apparatus for the synergistic solidification of radionuclides by red mud and lithium slag. Background Technology

[0002] Red mud is a large amount of solid waste generated during the alumina production process in the aluminum industry. Because it contains metal oxides such as iron, aluminum, and silicon, as well as trace amounts of naturally occurring radioactive elements like uranium and thorium, long-term open-air storage not only occupies significant land resources but also poses a serious threat to soil, groundwater, and the ecological environment due to rainwater runoff and the migration of alkaline leachate and radioactive nuclides. Furthermore, the specific activity of uranium and thorium in red mud is significantly higher than the limits for ordinary industrial solid waste.

[0003] Traditional radioactive contamination remediation technologies, such as cement solidification, asphalt solidification, or high-temperature vitrification, can partially reduce the risk of radionuclide leaching, but they have significant drawbacks: cement solidification bodies are prone to microcracks due to long-term hydration reactions, and radionuclides may be released secondary through these cracks; vitrification technology requires temperatures above 1300℃, resulting in extremely high energy costs and making it difficult to promote on a large scale; in addition, the high alkalinity of red mud requires additional neutralization treatment, further increasing the complexity and economic burden of environmental remediation.

[0004] As a byproduct of lithium resource development, the core value of the lithium beneficiation tailings from the Jardalite lies in its rich content of natural boron. There is room for research and development on how to utilize the lithium beneficiation tailings to treat radioactive elements in red mud.

[0005] Therefore, it is necessary to provide a method for the synergistic solidification of radionuclides using red mud and lithium slag to solve the above-mentioned technical problems. Summary of the Invention

[0006] This invention provides a method for the synergistic solidification of radionuclides using red mud and lithium slag, which solves the problem of high energy consumption and cost associated with existing vitrification technologies that require temperatures above 1300℃.

[0007] To solve the above-mentioned technical problems, the present invention provides a method for the synergistic solidification of radionuclides using red mud and lithium slag, comprising the following steps:

[0008] S1. Mix the dried red mud with lithium slag and add phosphate-based auxiliary curing agents to the mixture;

[0009] S2. Place the dried red mud, lithium slag and auxiliary curing agent into a ball mill and add deionized water to form an activated slurry.

[0010] S3. The activated slurry is processed into block materials using a molding device. These block materials are then transferred to a high-temperature sintering furnace and heated to 800-1200℃ to generate a borosilicate alumina glass phase, which contains UO2. 2+ and Th4+ Fixed inside the glass phase;

[0011] S4. The sintered bulk material is crushed into particles and then placed in a high-pressure reactor. A citric acid solution with a concentration of 3% to 8% is added, and a hydrothermal reaction is carried out at a temperature of 180 to 220°C and a pressure of 1.5 to 2.5 MPa to form a dense metaborate passivation layer on the surface of the borosilicate alumina glass phase particles.

[0012] Preferably, the phosphate-based curing agent in S1 is sodium phosphate.

[0013] Preferably, the phosphate-based auxiliary curing agent added to the mixture in S1 is 3% of the mass of the red mud.

[0014] Preferably, the borosilicate aluminum glass phase material after reaction in S4 is used in building materials.

[0015] The present invention also provides a molding apparatus for the method of co-solidifying radionuclides with red mud and lithium slag, comprising: a support;

[0016] A support box structure is mounted on the support platform;

[0017] The mold is detachably mounted on the carrier box structure, and the mold has multiple mold cavities.

[0018] A molding device, comprising a mounting frame, a hydraulic cylinder, a pressure plate, and multiple pressure heads, wherein the hydraulic cylinder is mounted on the support via the mounting frame and suspended above the mold, the pressure plate is mounted on the output end of the hydraulic cylinder, and the multiple pressure heads are mounted on the bottom of the pressure plate and correspond one-to-one with the multiple mold cavities;

[0019] A material holding device, comprising a material holding box, a pressure cap, a valve, and multiple discharge pipes, wherein the multiple discharge pipes are spaced apart and connected to the bottom of the material holding box, and the valve is used to control the connection status of the multiple discharge pipes;

[0020] A moving device, the moving device being used to drive the material holding device to move horizontally;

[0021] In use, the material container is detachably connected to the output end of the moving device, and the pressure cap is placed inside the material container and located on the material inside the material container; when the moving device drives the material container to be suspended above the mold, the multiple discharge pipes correspond one-to-one with the multiple mold cavities.

[0022] Preferably, the discharge pipe communicates with the interior of the holding box through the discharge hole. The valve includes a fixing frame, a connecting frame, a lifting component, multiple extension pipes, and multiple sealing blocks. The lifting component is installed on the holding box through the fixing frame. The multiple extension pipes, multiple sealing blocks, and multiple discharge pipes are arranged in a one-to-one correspondence. The top end of the extension pipe extends into the interior of the discharge pipe. The sealing block is installed on the top end of the extension pipe through a connecting rod and seals the discharge hole. The connecting frame connects the multiple extension pipes and is connected to the output end of the lifting component.

[0023] The inner diameter of the upper end of the discharge pipe is larger than the diameter of the sealing block, and the inner diameter of the lower end is the same as the outer diameter of the extension pipe.

[0024] Preferably, the moving device includes a drive cylinder and a drive plate. The drive cylinder is installed at the bottom of the support, the bottom end of the drive plate is connected to the drive cylinder, and the top end of the drive plate passes through the support through a strip hole.

[0025] The material container is detachably connected to the drive plate.

[0026] Preferably, it also includes two sliding frames, each sliding frame including a slide rail and an assembly frame. The two slide rails are installed on the support and located on both sides of the bearing box structure. The bottom end of the assembly frame is slidably installed on the slide rail, and the top of the assembly frame is provided with an assembly hole.

[0027] Connecting blocks are installed on both sides of the material container, and an assembly shaft is installed on the top of the connecting blocks. When the material container is detachably connected to the drive plate, the assembly shaft is inserted into the assembly hole.

[0028] Preferably, the carrier box structure includes a box body, two sliding rods, and multiple mounting blocks. The two sliding rods are installed on the support at intervals through the mounting blocks, and the box body is sleeved on the sliding rods.

[0029] The molding device also includes a vibration device, which drives the box body to reciprocate along the slide bar.

[0030] Preferably, an elliptical ring is installed at the bottom of the box body, the vibration device includes a rotating shaft, a gear and a drive rod, the top end of the rotating shaft passes through the support and is rotatably connected to the support, and the top end of the rotating shaft extends into the interior of the elliptical ring, the drive rod is horizontally installed on the rotating shaft, the length of the drive rod is between the maximum diameter and the minimum diameter of the elliptical ring, and the gear is installed at the bottom end of the rotating shaft;

[0031] The forming device also includes a toothed plate, one end of which is connected to the drive plate and the other end of which meshes with the gear.

[0032] Compared with related technologies, the method and molding apparatus for co-solidifying radionuclides using red mud and lithium slag provided by this invention have the following beneficial effects:

[0033] This invention provides a method for the synergistic solidification of radionuclides using red mud and lithium slag. The core value of the Jalda stone lithium tailings, a byproduct of lithium resource development, lies in its rich content of natural boron. This boron component exists stably in the form of borosilicate minerals and can synergistically react with aluminum and silicon oxides in the red mud under high-temperature conditions to generate a dense borosilicate-aluminum glassy phase network structure. This structure not only locks in radionuclides such as uranium and thorium through a dual mechanism of chemical bonding and lattice encapsulation, but also significantly improves the mechanical strength and environmental stability of the solidified product. Furthermore, the carboxylic acid groups of citric acid chelate with the particle surface, forming a dense metaborate passivation layer that effectively seals the microporous structure of the material surface, blocking the penetration pathways of water and ions, and further reducing the leaching risk of radionuclides in complex environments.

[0034] After mixing red mud and lithium slag in a certain mass ratio, the mixture is ball-milled to micron-sized particles and sintered at 1000℃ for 2 hours. Boron reacts fully with aluminum and silicon oxides in the red mud to form a three-dimensional network structure. The leaching rates of uranium and thorium can be reduced to below 0.05 Bq / L and 0.1 Bq / L, respectively, which is more than 99% lower than that of the original red mud.

[0035] Compared to traditional technologies, this process lowers the sintering temperature to 1000℃, achieving long-term stabilization of radionuclides solely through the synergistic reaction of red mud and lithium slag. This technological approach achieves the dual goals of long-term solidification of radionuclides and high-value utilization of solid waste through the synergistic effect of "treating waste with waste," effectively managing radioactive pollutants. Attached Figure Description

[0036] Figure 1 A flowchart illustrating the steps of the method for co-solidifying radionuclides using red mud and lithium slag provided by the present invention.

[0037] Figure 2 This is a schematic diagram of the molding device provided by the present invention;

[0038] Figure 3 for Figure 2 A cross-sectional view of the forming apparatus shown;

[0039] Figure 4 for Figure 3 The enlarged schematic diagram of part A shown below;

[0040] Figure 5 This is a schematic diagram of the material holding device provided by the present invention;

[0041] Figure 6 for Figure 2The front view of the molding apparatus shown;

[0042] Figure 7 This is a schematic diagram of the working state of the material holding device provided by the present invention, wherein... Figure 7 Image (a) is a schematic diagram showing the material container positioned between the pressure plate and the mold. Figure 7 (b) is a schematic diagram showing the state in which the pressure plate is about to push the activated slurry in the material container into the mold cavity;

[0043] Figure 8 A schematic diagram showing the state of the pressing device provided by the present invention applying pressure to the activated slurry in the mold cavity;

[0044] Figure 9 This is a schematic diagram of the working state of the vibration device provided by the present invention, wherein, Figure 9 Image (a) shows a schematic diagram of the box moving upwards as driven by the vibration device. Figure 9 (b) is a schematic diagram of the state in which the vibration device drives the box to move downward.

[0045] Numbering on the map:

[0046] 1. Support; 11. Strip hole;

[0047] 2. Carrier box structure; 21. Box body; 22. Slide rod; 23. Mounting block; 24. Elastic element; 211. Elliptical ring;

[0048] 3. Mold; 31. Mold cavity;

[0049] 4. Pressing device; 41. Mounting bracket; 42. Hydraulic cylinder; 43. Pressing plate; 44. Pressing head; 45. Positioning rod;

[0050] 5. Material holding device; 51. Material holding box; 52. Pressure cap; 53. Valve; 54. Discharge pipe;

[0051] 511. Connecting block; 512. Assembly shaft; 521. Groove; 501. Discharge hole;

[0052] 531. Fixing frame; 532. Connecting frame; 533. Lifting component; 534. Extension pipe; 535. Sealing block;

[0053] 6. Moving device; 61. Drive cylinder; 62. Driving plate; 63. Limiting rod;

[0054] 7. Sliding frame; 71. Slide rail; 72. Assembly frame;

[0055] 8. Vibration device; 81. Rotating shaft; 82. Gear; 83. Drive rod;

[0056] 9. Toothed plate. Detailed Implementation

[0057] 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.

[0058] This invention provides a method for the synergistic solidification of radionuclides using red mud and lithium slag.

[0059] Please refer to the following: Figure 1 In one embodiment of the present invention, the step includes the following steps:

[0060] S1. Mix dried red mud and lithium slag at a mass ratio of 60%~80% red mud and 20%~40% lithium slag, and add 1%~5% of the red mud mass of phosphate auxiliary solidifying agent to the mixture.

[0061] S2. Place the dried red mud, lithium slag and auxiliary curing agent into a ball mill and add deionized water to form an activated slurry, wherein the solid-liquid mass ratio is 1:1~1:3.

[0062] S3. The activated slurry is used to prepare block materials in a molding device. The block materials are then transferred to a high-temperature sintering furnace and heated to 800-1200℃ at a heating rate of 4-6℃ / min, and held for 1-3 hours to generate a borosilicate aluminate glass phase. UO2 is then... 2+ and Th 4+ Fixed inside the glass phase;

[0063] S4. The sintered bulk material is crushed into particles of 5-20 mm and then placed in a high-pressure reactor. A citric acid solution with a concentration of 3%-8% is added, and the liquid-solid ratio is controlled at 3:1. A hydrothermal reaction is carried out at a temperature of 180-220℃ and a pressure of 1.5-2.5 MPa for 1-3 hours to form a dense metaborate passivation layer on the surface of the borosilicate alumina glass phase particles.

[0064] In step S3, the alumina (Al2O3) and silica (SiO2) in the red mud undergo a melt copolymerization reaction with the boron oxide (B2O3) in the lithium slag to generate a dense borosilicate alumina glass phase Al-Si-BO network structure. When the activated slurry is used to prepare block materials, the molding pressure is 10~30 MPa. In the reaction process of step S4, the carboxylic acid groups of citric acid chelate with the particle surface to form a dense metaborate passivation layer, which effectively seals the microporous structure of the material surface, blocks the penetration path of water and ions, and further reduces the leaching risk of nuclides in complex environments.

[0065] After the reaction was completed, radionuclide leaching tests were conducted on the treated materials. The results showed that the leaching concentration of uranium was stable at 0.05~0.1 Bq / L, and the leaching concentration of thorium decreased to 0.1~0.2 Bq / L, both of which were significantly lower than the limit requirements of the "Radioactive Waste Safety Management Standard" (GB 9133-2022).

[0066] In this invention, the core value of the lithium tailings from the Jalda stone process, as a byproduct of lithium resource development, lies in its rich content of natural boron. This boron component exists stably in the form of borosilicate minerals and can undergo a synergistic reaction with aluminum and silicon oxides in red mud under high-temperature conditions to generate a dense borosilicate aluminum glass phase network structure. This structure can not only lock radioactive nuclides such as uranium and thorium through a dual mechanism of chemical bonding and lattice encapsulation, but also significantly improve the mechanical strength and environmental stability of the solidified product. Furthermore, the carboxylic acid groups of citric acid chelate with the particle surface to form a dense metaborate passivation layer, effectively sealing the microporous structure of the material surface, blocking the penetration paths of water and ions, and further reducing the leaching risk of nuclides in complex environments.

[0067] After mixing red mud and lithium slag in a certain mass ratio, the mixture is ball-milled to micron-sized particles and sintered at 1000℃ for 2 hours. Boron reacts fully with aluminum and silicon oxides in the red mud to form a three-dimensional network structure. The leaching rates of uranium and thorium can be reduced to below 0.05 Bq / L and 0.1 Bq / L, respectively, which is more than 99% lower than that of the original red mud.

[0068] Compared to traditional technologies, this process lowers the sintering temperature to 1000℃, achieving long-term stabilization of radionuclides solely through the synergistic reaction of red mud and lithium slag. This technological approach achieves the dual goals of long-term solidification of radionuclides and high-value utilization of solid waste through the synergistic effect of "treating waste with waste," effectively managing radioactive pollutants.

[0069] Preferably, the phosphate-based curing agent in S1 is sodium phosphate.

[0070] Preferably, the phosphate-based auxiliary curing agent added to the mixture in S1 is 3% of the mass of the red mud.

[0071] The borosilicate aluminum glass phase material after reaction in S4 is used in building materials.

[0072] Material mechanical property tests show that the compressive strength of the final product reaches 25~35 MPa, meeting the strength requirements of building wall materials and roadbed aggregates. Combined with hydrothermal strengthening treatment, reacting with 5% citric acid solution at 220℃ and 2.5 MPa for 2 hours can form a passivation layer on the material surface, further blocking the migration path of nuclides. The final product can be directly used in radiation protection buildings, industrial site remediation or road engineering, achieving 100% resource utilization of red mud and lithium slag. The processing cost is reduced by 40%~60% compared with the traditional vitrification process, combining environmental safety and economic feasibility.

[0073] The present invention also provides the following comparative embodiments:

[0074] Example 1:

[0075] Red mud and lithium slag were mixed at a mass ratio of 60%:40%, with 3% sodium phosphate as an auxiliary curing agent (based on the mass of the red mud). The ball milling process parameters were: solid-liquid ratio 1:2, milling time 6 hours, rotation speed 400 rpm, and median particle size D50 of the slurry was 10 μm. The molding pressure was 20 MPa, the sintering temperature was 1000℃, and the holding time was 2 hours. Hydrothermal intensification was achieved using a 5% citric acid solution with a liquid-to-solid ratio of 3:1, a reaction temperature of 220℃, a pressure of 2.5 MPa, and a time of 3 hours.

[0076] index result Uranium leaching concentration (Bq / L) 0.05 Thorium leaching concentration (Bq / L) 0.1 Compressive strength (MPa) 35 Processing cost reduction (%) 60 Resource utilization rate (%) 100

[0077] Example 2:

[0078] Red mud and lithium slag were mixed at a mass ratio of 70%:30%, with 3% sodium phosphate as an auxiliary curing agent added by weight of the red mud. The ball milling process parameters were: solid-liquid ratio 1:2, milling time 4 hours, rotation speed 400 rpm, and median particle size D50 of the slurry was 12 μm. The molding pressure was 20 MPa, the sintering temperature was 1000℃, and the holding time was 2 hours. Hydrothermal intensification was achieved using a 5% citric acid solution with a liquid-to-solid ratio of 3:1, a reaction temperature of 200℃, a pressure of 2 MPa, and a time of 3 hours.

[0079] index result Uranium leaching concentration (Bq / L) 0.08 Thorium leaching concentration (Bq / L) 0.15 Compressive strength (MPa) 28 Processing cost reduction (%) 50 Resource utilization rate (%) 100

[0080] Example 3:

[0081] Red mud and lithium slag were mixed at a mass ratio of 80%:20%, with 3% sodium phosphate as an auxiliary curing agent added by weight of the red mud. The ball milling process parameters were: solid-liquid ratio 1:2, milling time 4 hours, rotation speed 400 rpm, and median particle size D50 of the slurry was 15 μm. The molding pressure was 20 MPa, the sintering temperature was 800℃, and the holding time was 2 hours. Hydrothermal intensification was achieved using a 5% citric acid solution with a liquid-to-solid ratio of 3:1, a reaction temperature of 200℃, a pressure of 2 MPa, and a time of 3 hours.

[0082] index result Uranium leaching concentration (Bq / L) 0.12 Thorium leaching concentration (Bq / L) 0.25 Compressive strength (MPa) 22 Processing cost reduction (%) 40 Resource utilization rate (%) 100

[0083] Three examples systematically verified the influence of process parameters on the radionuclide solidification effect and material properties by adjusting the ratio of red mud to lithium slag, sintering temperature, and hydrothermal conditions. Example 1, using a 60%:40% ratio of red mud to lithium slag, combined with sintering at 1000℃ and high-intensity hydrothermal treatment, achieved optimal radionuclide stabilization and the highest compressive strength, while significantly reducing processing costs and demonstrating the best overall performance. Example 2, increasing the red mud ratio to 70%, showed a slight decrease in radionuclide solidification efficiency at the same sintering temperature due to the relatively reduced boron content in the lithium slag, but still met engineering application requirements, demonstrating the process's adaptability. Example 3, using an 80% red mud ratio and low-temperature sintering at 800℃, was limited by insufficient boron content and incomplete glass phase formation, resulting in increased radionuclide leaching risk and lower material strength, confirming the crucial role of sintering temperature and lithium slag ratio in the completeness of the reaction.

[0084] Overall, the lithium slag ratio, sintering temperature, and hydrothermal intensity are the core parameters for balancing the radionuclide solidification effect and cost: increasing the lithium slag ratio (≥30%) and sintering temperature (≥1000℃) can significantly enhance the formation efficiency of the borosilicate alumina glass phase, while sufficient hydrothermal reaction further strengthens the passivation barrier. Although there are gradient differences in the performance of the final product under different conditions, all embodiments achieved 100% resource utilization of red mud and lithium slag, proving that the technology can be flexibly adjusted to adapt to diverse environmental protection and engineering needs.

[0085] The present invention also provides a molding apparatus.

[0086] The molding device is used in step S3 of the method for co-solidifying radionuclides with red mud and lithium slag to prepare block materials from activated slurry.

[0087] The molding apparatus provided by this invention is not limited to the step S3 of the method for co-curing radionuclides with red mud and lithium slag to prepare block materials from activated slurry. It can also be used to prepare block materials from slurry in other fields, such as pressing ceramic materials into square blanks or pressing building materials into square blocks. When used in different fields, the size of the mold cavity 31 and the pressing head 44 can be adjusted according to specific needs.

[0088] Please see Figure 2 A molding device, comprising: a support 1;

[0089] The carrier box structure 2 is installed on the support 1;

[0090] Mold 3, which is detachably mounted on the carrier box structure 2, and has multiple mold cavities 31;

[0091] The molding device 4 includes a mounting frame 41, a hydraulic cylinder 42, a pressure plate 43, and multiple pressure heads 44. The hydraulic cylinder 42 is mounted on the support 1 via the mounting frame 41 and suspended above the mold 3. The pressure plate 43 is mounted on the output end of the hydraulic cylinder 42. The multiple pressure heads 44 are mounted on the bottom of the pressure plate 43 and correspond one-to-one with the multiple mold cavities 31.

[0092] The material holding device 5 includes a material holding box 51, a pressure cover 52, a valve 53, and a plurality of discharge pipes 54. The plurality of discharge pipes 54 are spaced apart and connected to the bottom of the material holding box 51. The valve 53 is used to control the connection state of the plurality of discharge pipes 54.

[0093] The moving device 6 is used to drive the material holding device 5 to move horizontally;

[0094] In use, the material container 51 is detachably connected to the output end of the moving device 6, and the pressure cover 52 is placed inside the material container 51 and located on the material inside the material container 51; when the moving device 6 drives the material container 51 to be suspended above the mold 3, the multiple discharge pipes 54 correspond one-to-one with the multiple mold cavities 31.

[0095] This molding device is mainly used in small-scale applications such as laboratories. The shape and area of ​​the pressure cap 52 are the same as the cross-sectional properties and area of ​​the inner cavity of the material container 51.

[0096] In use, the activated slurry is loaded into the material container 51, then the pressure cap 52 is installed into the material container 51 and positioned on the activated slurry. The material container 51 is then assembled with the output end of the moving device 6. The moving device 6 drives the material container 51 between the mold 3 and the pressure plate 43. At this time, each discharge pipe 54 is aligned with the mold cavity 31. Figure 7 (a);

[0097] Then the hydraulic cylinder 42 pushes the pressure plate 43 so that its pressure head 44 abuts against the pressure cap 52, such as Figure 7 (b) Then open valve 53 to connect multiple discharge pipes 54 with the inside of the material box 51. Hydraulic cylinder 42 pushes down pressure plate 43, pressure plate 43 pushes down pressure cover 52, and pressure cover 52 squeezes the activated slurry inside the material box 51 through the discharge pipes 54 into the corresponding mold cavity 31. After the hydraulic cylinder 42 pushes down pressure plate 43 for the preset stroke, close valve 53.

[0098] Hydraulic cylinder 42 lifts the pressure plate 43 to separate it from the pressure cap 52. Then, moving device 6 drives the material holding device 5 to separate from the mold 3. Hydraulic cylinder 42 pushes the pressure plate 43 down, and the pressure head 44 at the bottom of the pressure plate 43 enters the corresponding mold cavity 31, applying a preset pressure to the activated slurry in the mold cavity 31. Figure 8Then, mold 3 is removed from box 21, and mold 3 can be transferred to a high-temperature sintering furnace for sintering.

[0099] Thus, this equipment can automatically inject a preset activation slurry into the mold and perform molding operation within a preset pressure range. Furthermore, the molding device 4 can discharge the activation slurry into the mold cavity 31 and apply a preset pressure to the activation slurry in the mold cavity 31, thus simplifying the equipment structure.

[0100] The mold 3 includes a mold box and a partition frame. The partition frame is set inside the mold box and divides the inner cavity of the mold box into multiple mold cavities 31, which are 16 in this embodiment.

[0101] The invention also includes a control module, the input ends of the hydraulic cylinder 42 and the moving device 6 are both electrically connected to the control module, which is used to control the extension and retraction of the hydraulic cylinder 42 and the output pressure, and to control the movement stroke of the moving device 6, etc.

[0102] Among them, mold 3 is placed directly inside box 21.

[0103] In one embodiment, the separator and the mold box are detachable. The separator is placed directly inside the mold box. After baking and molding, the separator is removed to facilitate the removal of the molded slurry.

[0104] In another embodiment, the separator is integrated with the mold box, and the molded slurry is ejected by providing an ejection structure at the bottom of the mold box;

[0105] When the divider and the mold box are detachable, an ejector structure can also be installed at the bottom of the mold box.

[0106] Preferably, a plurality of grooves 521 are provided on the top of the pressure cover 52. When the pressure cover 52 is located below the pressure plate 43, the plurality of grooves 521 are arranged in a one-to-one correspondence with the plurality of pressure heads 44. When the hydraulic cylinder 42 pushes down the pressure plate 43, the pressure head 44 can be embedded into the groove 521 accordingly, thereby improving the stability of the assembly.

[0107] Please see Figure 3 and Figure 4In this embodiment, the discharge pipe 54 is connected to the interior of the material container 51 through the discharge hole 501. The valve component 53 includes a fixing frame 531, a connecting frame 532, a lifting component 533, multiple extension pipes 534, and multiple sealing blocks 535. The lifting component 533 is installed on the material container 51 through the fixing frame 531. The multiple extension pipes 534, multiple sealing blocks 535, and multiple discharge pipes 54 are arranged in a one-to-one correspondence. The top end of the extension pipe 534 extends into the interior of the discharge pipe 54. The sealing block 535 is installed on the top end of the extension pipe 534 through a connecting rod and blocks the discharge hole 501. The connecting frame 532 connects the multiple extension pipes 534 and is connected to the output end of the lifting component 533.

[0108] The upper inner diameter of the discharge pipe 54 is larger than the diameter of the sealing block 535, and the lower inner diameter is the same as the outer diameter of the extension pipe 534.

[0109] The upper end of the discharge pipe 54 is connected to the lower end through a tapered part.

[0110] When the material container 51 moves between the mold 3 and the pressure plate 43, the discharge pipe 54 is set one-to-one with the mold cavity 31. At this time, the lifting component 533 pushes down the connecting frame 532, and the connecting frame 532 drives multiple extension pipes 534 to descend, so that their bottom ends enter the mold cavity 31 and their top ends drive the sealing block 535 into the discharge pipe 54. The top end enters the lower end of the discharge pipe 54, and the discharge hole 501 is connected to the discharge pipe 54. Thus, when the pressure plate 43 pushes down the pressure cover 52, the internal material can enter the mold cavity 31 in sequence through the discharge hole 501, the discharge pipe 54 and the extension pipe 534.

[0111] After the material discharge is completed, the lifting component 533 lifts the connecting frame 532, causing the extension tube 534 to move upward, so that its bottom end moves out of the mold cavity 31, and the top end drives the sealing block 535 to seal the discharge hole 501.

[0112] This allows for the simultaneous sealing or unsealing of multiple discharge pipes 54; and by setting an extension pipe 534, the extension pipe 534 can extend into the mold cavity 31, allowing the material to be introduced into the mold cavity 31 more stably, avoiding material splashing, etc.

[0113] As an optional embodiment, the lifting component 533 is an electric push cylinder, which is mounted on the fixed frame 531 and its output end is connected to the connecting frame 532. The electric push cylinder can quickly control the connection state of the discharge pipe 54. The input end of the electric push cylinder is connected to the output end of the control module, and the control module controls the start-up state and stroke of the electric push cylinder.

[0114] As another optional embodiment, the lifting component 533 includes a nut and a bolt. The nut is installed on the fixed frame 531, and the bolt passes through the nut and is rotatably connected to the connecting frame 532 and threadedly connected to the nut. A knob is installed on the top of the bolt to facilitate turning the bolt. The operator manually turns the bolt to drive the extension pipe 534 to rise or fall through the connecting frame 532, thereby controlling the connection state of the discharge pipe 54.

[0115] Preferably, the top of the sealing block 535 is set in a conical shape to prevent the activating slurry from remaining on the top of the sealing block 535.

[0116] Please refer to 3. In this embodiment, the moving device 6 includes a drive cylinder 61 and a drive plate 62. The drive cylinder 61 is installed at the bottom of the support 1. The bottom end of the drive plate 62 is connected to the drive cylinder 61. The top end of the drive plate 62 passes through the support 1 through the strip hole 11.

[0117] The material container 51 is detachably connected to the drive plate 62.

[0118] When it is necessary to move the container 51, the drive cylinder 61 drives the drive plate 62 to move horizontally, and the drive plate 62 drives the container 51 to move, thereby realizing the horizontal movement of the container 51.

[0119] Preferably, the moving device 6 further includes a limiting rod 63, which is horizontally installed in the strip hole 11. The driving plate 62 is sleeved on the limiting rod 63 to form a sliding connection, thereby moving the driving plate 62 along the limiting rod 63 and improving the stability of the driving plate 62 when it moves.

[0120] Please see Figure 3 and Figure 5 As an optional method in this embodiment, an insertion port is provided at the bottom of the fixing frame 531, and an insertion block is provided at the top of the driving plate 62. During assembly, the insertion port is inserted into the insertion block to achieve detachable assembly.

[0121] As another optional approach in this embodiment, mounting holes can be made on the fixing frame 531 and the driving plate 62 respectively, and detachable installation can be carried out using bolts and nuts.

[0122] In other embodiments, the moving device 6 may also be configured as a motor and lead screw structure or a belt conveyor, etc.

[0123] As a preferred embodiment, the molding device further includes two sliding frames 7, each sliding frame 7 including a slide rail 71 and an assembly frame 72. The two slide rails 71 are installed on the support 1 and located on both sides of the bearing box structure 2. The bottom end of the assembly frame 72 is slidably installed on the slide rail 71, and the top of the assembly frame 72 is provided with an assembly hole.

[0124] Connecting blocks 511 are installed on both sides of the material container 51, and an assembly shaft 512 is installed on the top of the connecting block 511. When the material container 51 is detachably connected to the drive plate 62, the assembly shaft 512 is inserted into the assembly hole.

[0125] When the container 51 is installed with the drive plate 62, the bottom end of the fixing bracket 531 is inserted into the drive plate 62, and the mounting shaft 512 is inserted into the mounting hole accordingly. When the drive cylinder 61 drives the drive plate 62 to move the container 51, the mounting bracket 72 can support the container 51 and slide along the slide rail 71. The sliding bracket 7 can assist in supporting the container 51 and improve the stability of the container 51 in use.

[0126] Preferably, two connecting blocks 511 are installed on each side of the material container 51, and two assembly holes are opened on each corresponding assembly frame 72.

[0127] Please see Figure 2 The carrier box structure 2 includes a box body 21, two sliding rods 22, and multiple mounting blocks 23. The two sliding rods 22 are installed on the support 1 at intervals through the mounting blocks 23, and the box body 21 is sleeved on the sliding rods 22.

[0128] The molding device also includes a vibration device 8, which is used to drive the box 21 to reciprocate along the slide bar 22.

[0129] By setting up a vibration device 8, after the activation slurry is injected into the corresponding mold cavity 31 through the extension tube 534, the vibration device 8 drives the box body 21 to vibrate, thereby driving the mold 3 to vibrate back and forth, so that the activation slurry inside the box body 21 can be more flat and compacted in the mold 3, in preparation for subsequent pressurization.

[0130] Preferably, the carrier box structure 2 further includes multiple elastic elements 24, which are sleeved on both ends of the slide rod 22 and located between the box body 21 and the mounting block 23. The elastic element 24 provides elastic buffering to improve the stability of the box body 21 during reciprocating vibration.

[0131] The elastic element 24 is an elastic component such as a spring or a leaf spring.

[0132] Please see Figure 6 and Figure 9As an optional embodiment, an elliptical ring 211 is installed at the bottom of the box 21. The vibration device 8 includes a rotating shaft 81, a gear 82, and a drive rod 83. The top end of the rotating shaft 81 passes through the support 1 and is rotatably connected to the support 1. The top end of the rotating shaft 81 extends into the interior of the elliptical ring 211. The drive rod 83 is horizontally installed on the rotating shaft 81. The length of the drive rod 83 is between the maximum diameter and the minimum diameter of the elliptical ring 211. The gear 82 is installed at the bottom end of the rotating shaft 81.

[0133] The forming device also includes a toothed plate 9, one end of which is connected to the drive plate 62, and the other end of which meshes with the gear 82.

[0134] When the extension tube 534 injects the activated slurry into the corresponding mold cavity 31, the drive cylinder 61 drives the material holding device 5 to separate from the mold 3 and the pressing device 4 through the drive plate 62. During this process, the drive plate 62 simultaneously drives the toothed plate 9 to move, the toothed plate 9 drives the gear 82 to rotate, the gear 82 drives the rotating shaft 81 to rotate, the rotating shaft 81 drives the drive rod 83 to rotate, and the drive rod 83 rotates along the inner side of the elliptical ring 211. When the drive rod 83 acts on the side wall corresponding to the short diameter of the elliptical ring 211 in sequence, it pushes the elliptical ring 211 to move back and forth, thereby driving the box body 21 to vibrate back and forth along the slide rod 22. During the process of the moving device 6 driving the material holding box 51 to separate from the mold 3, the toothed plate 9 is driven to move and drive the vibration device 8 to drive the box body 21 to vibrate, so that no additional drive equipment is required, simplifying the equipment.

[0135] That is, during the process of switching the function of the molding device 4 from discharging the activated slurry into the mold cavity 31 to applying a preset pressure to the activated slurry in the mold cavity 31, the reciprocating vibration function of the material container 51 is realized.

[0136] In this example, as a preferred embodiment, a one-way bearing is installed on the rotating shaft 81, and the gear 82 is installed on the one-way bearing;

[0137] When the moving device 6 drives the material holding device 5 to move between the mold 3 and the pressing device 4, the toothed plate 9 drives the gear 82 to move the rotating shaft 81 through the one-way bearing. When the moving device 6 drives the material holding device 5 to separate from the mold 3, the toothed plate 9 drives the gear 82 to move the rotating shaft 81 through the one-way bearing.

[0138] As another alternative to this embodiment, the toothed plate 9 can be replaced with a motor and a frame. The motor is mounted on the support 1 via the frame, and the output shaft of the motor is connected to the rotating shaft 81, so that the rotating shaft 81 can be driven to rotate by the motor.

[0139] In this embodiment, the molding device 4 also includes a plurality of positioning rods 45. The bottom end of the positioning rod 45 passes through the top of the mounting frame 41 and is connected to the pressure plate 43. The positioning rods 45 limit the pressure plate 43 in the horizontal direction when it is raised or lowered, thereby improving the stability of the pressure plate 43.

[0140] The working principle of the molding device provided by this invention is as follows:

[0141] In use, the activated slurry is loaded into the material container 51, then the pressure cap 52 is installed into the material container 51 and positioned on the activated slurry. The material container 51 is then assembled with the output end of the moving device 6. The moving device 6 drives the material container 51 between the mold 3 and the pressure plate 43. At this time, each discharge pipe 54 is aligned with the mold cavity 31. Figure 7 (a);

[0142] Then the hydraulic cylinder 42 pushes the pressure plate 43 so that its pressure head 44 abuts against the pressure cap 52, such as Figure 7 (b) Then open valve 53 to connect multiple discharge pipes 54 with the inside of the material box 51. Hydraulic cylinder 42 pushes down pressure plate 43, pressure plate 43 pushes down pressure cover 52, and pressure cover 52 squeezes the activated slurry inside the material box 51 through the discharge pipes 54 into the corresponding mold cavity 31. After the hydraulic cylinder 42 pushes down pressure plate 43 for the preset stroke, close valve 53.

[0143] Hydraulic cylinder 42 lifts the pressure plate 43 to separate it from the pressure cap 52. Then, moving device 6 drives the material holding device 5 to separate from the mold 3. Hydraulic cylinder 42 pushes the pressure plate 43 down, and the pressure head 44 at the bottom of the pressure plate 43 enters the corresponding mold cavity 31, applying a preset pressure to the activated slurry in the mold cavity 31. Figure 8 Then, mold 3 is removed from box 21, and subsequently transferred to a high-temperature sintering furnace for firing.

[0144] When the extension tube 534 injects the activated slurry into the corresponding mold cavity 31, the drive cylinder 61 drives the material holding device 5 to separate from the mold 3 and the pressing device 4 through the drive plate 62. During this process, the drive plate 62 simultaneously drives the toothed plate 9 to move, the toothed plate 9 drives the gear 82 to rotate, the gear 82 drives the rotating shaft 81 to rotate, the rotating shaft 81 drives the drive rod 83 to rotate, and the drive rod 83 rotates along the elliptical ring 211. When the drive rod 83 acts on the side wall corresponding to the short diameter of the elliptical ring 211 in sequence, it pushes the elliptical ring 211 to move back and forth, thereby driving the box 21 to vibrate back and forth along the slide rod 22. During the process of the moving device 6 driving the material holding box 51 to separate from the mold 3, the toothed plate 9 moves and drives the vibration device 8 to vibrate the box 21, so that the activated slurry inside the box 21 can be more flat and compacted in the mold 3, in preparation for subsequent pressurization.

[0145] That is, during the process of switching the function of the molding device 4 from discharging the activated slurry into the mold cavity 31 to applying a preset pressure to the activated slurry in the mold cavity 31, the reciprocating vibration function of the material container 51 is realized.

[0146] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for the synergistic solidification of radionuclides using red mud and lithium slag, characterized in that, Includes the following steps: S1. Mix the dried red mud with lithium slag and add phosphate-based auxiliary curing agents to the mixture; S2. Place the dried red mud, lithium slag and auxiliary curing agent into a ball mill and add deionized water to form an activated slurry. S3. The activated slurry is processed into block materials using a molding device. These block materials are then transferred to a high-temperature sintering furnace and heated to 800-1200℃ to generate a borosilicate alumina glass phase, which contains UO2. 2+ and Th 4+ Fixed inside the glass phase; S4. The sintered bulk material is crushed into particles and then placed in a high-pressure reactor. A citric acid solution with a concentration of 3% to 8% is added, and a hydrothermal reaction is carried out at a temperature of 180 to 220°C and a pressure of 1.5 to 2.5 MPa to form a dense metaborate passivation layer on the surface of the borosilicate alumina glass phase particles.

2. The method for co-solidifying radionuclides with red mud and lithium slag according to claim 1, characterized in that, The phosphate-based curing agent in S1 is sodium phosphate.

3. The method for co-solidifying radionuclides with red mud and lithium slag according to claim 1, characterized in that, The phosphate-based auxiliary curing agent added to the mixture in S1 is 3% of the mass of the red mud.

4. The method for co-solidifying radionuclides with red mud and lithium slag according to claim 1, characterized in that, The borosilicate aluminum glass phase material after reaction in S4 is used in building materials.

5. A molding apparatus, characterized in that, Step S3 of the method for co-solidifying radionuclides with red mud and lithium slag as described in any one of claims 1-4 includes: a support platform; A support box structure is mounted on the support platform; The mold is detachably mounted on the carrier box structure, and the mold has multiple mold cavities. A molding device, comprising a mounting frame, a hydraulic cylinder, a pressure plate, and multiple pressure heads, wherein the hydraulic cylinder is mounted on the support via the mounting frame and suspended above the mold, the pressure plate is mounted on the output end of the hydraulic cylinder, and the multiple pressure heads are mounted on the bottom of the pressure plate and correspond one-to-one with the multiple mold cavities; A material holding device, comprising a material holding box, a pressure cap, a valve, and multiple discharge pipes, wherein the multiple discharge pipes are spaced apart and connected to the bottom of the material holding box, and the valve is used to control the connection status of the multiple discharge pipes; A moving device, the moving device being used to drive the material holding device to move horizontally; In use, the material container is detachably connected to the output end of the moving device, and the pressure cap is placed inside the material container and located on the material inside the material container; when the moving device drives the material container to be suspended above the mold, the multiple discharge pipes correspond one-to-one with the multiple mold cavities.

6. The molding apparatus according to claim 5, characterized in that, The discharge pipe communicates with the interior of the material container through the discharge hole. The valve includes a fixing frame, a connecting frame, a lifting component, multiple extension pipes, and multiple sealing blocks. The lifting component is installed on the material container through the fixing frame. The multiple extension pipes, multiple sealing blocks, and multiple discharge pipes are arranged in a one-to-one correspondence. The top end of the extension pipe extends into the interior of the discharge pipe. The sealing block is installed on the top end of the extension pipe through a connecting rod and seals the discharge hole. The connecting frame connects the multiple extension pipes and is connected to the output end of the lifting component. The inner diameter of the upper end of the discharge pipe is larger than the diameter of the sealing block, and the inner diameter of the lower end is the same as the outer diameter of the extension pipe.

7. The molding apparatus according to claim 5, characterized in that, The moving device includes a drive cylinder and a drive plate. The drive cylinder is installed at the bottom of the support, the bottom end of the drive plate is connected to the drive cylinder, and the top end of the drive plate passes through the support through a strip hole. The material container is detachably connected to the drive plate.

8. The molding apparatus according to claim 7, characterized in that, It also includes two sliding frames, each of which includes a slide rail and an assembly frame. The two slide rails are mounted on the support and located on both sides of the bearing box structure. The bottom end of the assembly frame is slidably mounted on the slide rail, and the top of the assembly frame is provided with an assembly hole. Connecting blocks are installed on both sides of the material container, and an assembly shaft is installed on the top of the connecting blocks. When the material container is detachably connected to the drive plate, the assembly shaft is inserted into the assembly hole.

9. The molding apparatus according to claim 8, characterized in that, The carrier box structure includes a box body, two sliding rods, and multiple mounting blocks. The two sliding rods are installed on the support platform at intervals through the mounting blocks, and the box body is sleeved on the sliding rods. The molding device also includes a vibration device, which drives the box body to reciprocate along the slide bar.

10. The molding apparatus according to claim 9, characterized in that, An elliptical ring is installed at the bottom of the box. The vibration device includes a rotating shaft, a gear, and a drive rod. The top end of the rotating shaft passes through the support and is rotatably connected to the support. The top end of the rotating shaft extends into the interior of the elliptical ring. The drive rod is horizontally installed on the rotating shaft. The length of the drive rod is between the maximum and minimum diameter of the elliptical ring. The gear is installed at the bottom end of the rotating shaft. The forming device also includes a toothed plate, one end of which is connected to the drive plate and the other end of which meshes with the gear.

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