Iron phosphate-based high-entropy glass-ceramics and methods of making the same
By preparing ferric phosphate-based high-entropy glass-ceramic solidified bodies, and utilizing the Fe2O3-P2O5-B2O3 glass phase and high-entropy monazite phase, the problem of solidifying multiple actinide nuclides in high-level radioactive waste was solved, achieving efficient and simple solidification results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHWEAT UNIV OF SCI & TECH
- Filing Date
- 2026-04-03
- Publication Date
- 2026-05-26
AI Technical Summary
Existing technologies are not efficient and convenient for simultaneously solidifying multiple actinide nuclides in high-level radioactive waste, and existing preparation methods are complex and difficult to achieve large-scale production.
The solidified iron phosphate-based high-entropy glass-ceramic is prepared by a one-step melt heat treatment method, combining the Fe2O3-P2O5-B2O3 glass phase and the high-entropy monazite phase to form an amorphous phase and a crystalline phase, which contains a variety of actinide nuclides.
This method enables efficient solidification of various actinide nuclides, simplifies the process, reduces production costs, improves preparation efficiency, and ensures the structural integrity of the solidified body.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of glass ceramics (or microcrystalline glass) and relates to a ferrophosphate-based high-entropy glass ceramic and its preparation method, which is suitable for the simultaneous curing of multiple (sub)actinide nuclides in HLW. Background Technology
[0002] The large-scale development of nuclear energy has also brought with it the significant challenge of the safe disposal of high-level radioactive waste (HLW). Currently, the internationally accepted solution for HLW treatment and disposal is "solidification-deep geological disposal," which involves first solidifying the HLW into a specific substrate before deep geological landfilling. Common solidification methods include vitrification, glass-ceramic solidification, and ceramic solidification.
[0003] Glass-ceramic curing combines the advantages of both glass and ceramic curing. Currently, the main glass phases used in glass-ceramic curing are borosilicate glass and phosphate glass. Because borosilicate glass has insufficient tolerance for sulfates and phosphates, it is prone to developing a "yellow phase," making ferrophosphate glass a gradually emerging alternative substrate for high-level radioactive waste curing. Ferrophosphate glass has a lower melting temperature and higher solubility, enabling it to contain certain high-concentration radioactive waste components, such as actinides and rare earth elements. The ceramic crystalline phases in glass-ceramic curing bodies include pyrochlore, perovskite, and monazite. Among these, monazite, a mineral that can exist stably in nature for a long time, often exhibits isomorphous substitutions of Ce and La by elements such as U, Th, and Pu, showing potential for curing long-lived lanthanides and actinides, and is therefore considered an ideal candidate curing matrix.
[0004] Currently, the main methods for preparing glass ceramics include the "melt-quench" method, the two-step heat treatment method, and the powder sintering method. Among them, although the "melt-quench" method is technically mature, simple rapid cooling often makes it difficult to form uniform microcrystals; the two-step heat treatment method is relatively complex; and the powder sintering method is complex and difficult to produce on a large scale.
[0005] High-entropy materials are multi-component materials composed of five or more elements in near-equiatomic ratios. Currently, various high-entropy ceramics have been studied for nuclear solidification, demonstrating superior chemical / irradiation stability compared to single-component ceramics, enabling the synergistic solidification of multiple nuclides. In recent years, high-entropy glass ceramics have attracted attention: in the capacitor field, through the synergistic effect of high-entropy strategies and multiphase structure design, high-entropy glass ceramic materials with ultra-high energy storage density, excellent efficiency, and fast discharge performance have been successfully developed; in the field of industrial waste treatment, the preparation of high-entropy glass ceramics using solid waste as the main raw material not only exhibits good performance but also improves the utilization rate of solid waste resources. High-entropy glass ceramics (HLWs) contain a large number of actinide nuclides with complex and diverse compositions, which can themselves serve as a source of entropy for high-entropy glass ceramics. Therefore, high-entropy glass ceramics can be considered a potential carrier for the one-step solidification of multiple nuclides. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of the prior art and to provide a high-entropy glass-ceramic solidified body that can simultaneously cure multiple (sub)actinide nuclides in HLW by utilizing the chemical flexibility of glass, the high chemical stability and high entropy of ceramics.
[0007] To achieve the above objectives of this invention, the following technical solution is adopted: A ferric phosphate-based high-entropy glass-ceramic solidified body, with the general chemical formula (100- x ()( y Fe2O3-(90- y (P₂O₅-10B₂O₃)-0.5 x P2O5-( x / 2 n ()( Ln 2O3) (mol%), of which x The total molar ratio of lanthanide oxides ( x =0, 5, 10, 15, 20, 25, 30 mol%), y =15~35 mol%.
[0008] Furthermore, this high-entropy glass-ceramic solidified body comprises an amorphous phase and a crystalline phase, wherein the glassy phase is Fe2O3-P2O5-B2O3-based glass, and the crystalline phase consists only of a high-entropy monazite phase, the chemical formula of which is ( Ln 1 / n )PO4, in which Ln =La, Ce, Nd, Sm, Eu, Gd, Dy, Ho, Er, n If n is an integer and 5 ≤ n ≤ 7, it can be ( Ln 1 / 5 )PO4、( Ln 1 / 6 )PO4、( Ln 1 / 7 )PO4.
[0009] Furthermore, the preparation method of this iron phosphate-based high-entropy glass-ceramic solidified body includes the following steps: Step 1: Weigh the raw materials according to the following ratio: 20.4-30 parts by weight of Fe2O3, 55.3-60 parts by weight of P2O5, 6.8-10 parts by weight of B2O3, and 0-17.4 parts by weight of lanthanide oxides.
[0010] Step 2: Ball mill the various raw materials to obtain a uniformly mixed material, and then dry it.
[0011] Step 3: The mixture is placed in a corundum crucible and placed in a high-temperature furnace. The temperature is increased to the melting temperature at a rate of 4℃ / min and held. Then, the temperature is decreased to the nucleation temperature at the same rate and held. Next, the temperature is increased to the crystallization temperature at a rate of 4℃ / min and held. Finally, the mixture is cooled in the furnace to obtain a solidified iron phosphate-based high-entropy glass-ceramic.
[0012] Furthermore, in step 1, the lanthanide oxide can be any five or more of the following: La2O3, CeO2, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Dy2O3, Ho2O3, and Er2O3.
[0013] Furthermore, the ball milling method in step 2 can be either dry ball milling or wet ball milling. The grinding media can be either zirconia balls or alumina balls, and the dispersant in wet ball milling can be either anhydrous ethanol or acetone.
[0014] Furthermore, in step 2, the mass ratio of raw material: grinding media: (dispersant) is 1:1.5:(1.5), and the ball milling time is 6~12h.
[0015] Furthermore, the sintering technology used in step 3 can be either microwave sintering or traditional solid-state sintering.
[0016] Furthermore, in step 3, the melting temperature is 1200℃~1400℃, the nucleation temperature is 550℃~630℃, the crystallization temperature is 690℃~890℃, and the holding time is 60min~120min.
[0017] Compared with the prior art, the present invention has the following advantages: (1) The iron phosphate-based high-entropy glass-ceramic solidified body prepared by the present invention has excellent adaptability to high-level radioactive waste with complex composition. It can simultaneously solidify multiple (sub)actinide nuclides in HLW into the ceramic phase of the glass-ceramic, and has strong containment capacity.
[0018] (2) The iron phosphate-based high-entropy glass-ceramic solidified body prepared by the present invention has good composition controllability, good interface bonding between the high-entropy ceramic phase and the iron phosphate glass phase, and uniform component distribution, which is conducive to ensuring the structural integrity of the solidified body during long-term treatment.
[0019] (3) The present invention uses a one-step melting heat treatment process to prepare iron phosphate-based high-entropy glass ceramic solidified body, which simplifies the process flow, shortens the production cycle, reduces labor and equipment costs, and improves preparation efficiency. Attached Figure Description
[0020] Figure 1 The above are XRD patterns of the iron phosphate-based high-entropy glass-ceramic solidified bodies prepared in Examples 1-7 of this invention. Figure 2 This is a SEM image of the iron phosphate-based high-entropy glass-ceramic solidified body prepared in Example 5 of the present invention. Figure 3 The image shown is a SEM-EDS image of the iron phosphate-based high-entropy glass-ceramic solidified body prepared in Example 5 of this invention. Detailed Implementation
[0021] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.
[0022] Examples 1-7: A ferric phosphate-based high-entropy glass-ceramic solidified body, designed with the chemical formula (100- x (30Fe₂O₃-60P₂O₅-10B₂O₃)-0.5 x P2O5-0.1 x La2O3-0.2 x CeO2-0.1 x Nd₂O₃-0.1 x Sm2O3-0.1 x Gd₂O₃) (mol%), of which x The total molar ratio of lanthanide oxides ( x =0, 5, 10, 15, 20, 25, 30 mol%), y = 30 mol%. The designed solidified body composition consists of an amorphous phase of Fe2O3-P2O5-B2O3 glass phase and a crystalline phase of high-entropy monazite phase. Ln 1 / 5 )PO4( Ln =La、Ce 、 Nd 、 Sm 、 Gd). The specific oxide ratios in Examples 1-7 are shown in Table 1, and the preparation process includes the following steps: (1) Ingredients: Fe2O3, H3BO3, NH4H2PO4, La2O3, CeO2, Nd2O3, Sm2O3 and Gd2O3 are used as raw materials and are mixed according to stoichiometric ratio.
[0023] (2) Mixing: The raw materials, zirconia balls, and anhydrous ethanol were loaded into a ball mill jar and wet-milled for 6 hours using a planetary ball mill, and then dried at 60°C. Zirconia balls were used as the grinding medium and anhydrous ethanol was used as the dispersant. The mass ratio of raw materials:zirconia balls:anhydrous ethanol was 1:1.5:1.5. The ball milling speed was 400 r / min and the ball milling time was 6 hours.
[0024] (3) Firing: The mixture was placed in an alumina crucible and heated to 1200℃ in a muffle furnace at a heating rate of 4℃ / min. After holding at this temperature for 120 min, it was cooled to the nucleation temperature at a rate of 4℃ / min and held for 60 min. Then, it was heated to the crystallization temperature at a rate of 4℃ / min and held for 60 min. Finally, it was cooled in the furnace to obtain a solidified iron phosphate-based high-entropy glass-ceramic. The nucleation and crystallization temperatures used in specific examples 1 to 7 are shown in Table 2.
[0025] Table 1. Molar ratios of the oxides in Examples 1-7 above Example serial number <![CDATA[Fe2O3]]> <![CDATA[P2O5]]> <![CDATA[B2O3]]> <![CDATA[La2O3]]> <![CDATA[CeO2]]> <![CDATA[Nd2O3]]> <![CDATA[Sm2O3]]> <![CDATA[Gd2O3]]> 1 Ln0 0 30.0 60.0 10.0 0.0 0.0 0.0 0.0 0.0 2 Ln5 5 28.4 59.2 9.5 0.5 1.0 0.5 0.5 0.5 3 Ln10 10 26.7 58.4 8.9 1.0 2.0 1.0 1.0 1.0 4 Ln15 15 25.1 57.6 8.4 1.5 3.0 1.5 1.5 1.5 5 Ln20 20 23.5 56.9 7.8 2.0 3.9 2.0 2.0 2.0 6 Ln25 25 22.0 56.1 7.3 2.4 4.9 2.4 2.4 2.4 7 Ln30 30 20.4 55.3 6.8 2.9 5.8 2.9 2.9 2.9 Table 2. Nucleation and crystallization temperatures used in Examples 1-7 above. Example serial number Nucleation temperature / °C Crystallization temperature / ℃ 1 Ln0 580 780 2 Ln5 580 780 3 Ln10 590 790 4 Ln15 590 790 5 Ln20 610 740 6 Ln25 590 740 7 Ln30 590 740 The phase composition, microstructure and chemical composition of the iron phosphate-based high-entropy glass-ceramic solidified bodies prepared by one-step melt heat treatment in Examples 1 to 7 were characterized. Figure 1 The iron phosphate-based high-entropy glass-ceramic cured bodies prepared in Examples 1-7 above ( x XRD patterns of (0~30 mol%). Figure 2 The iron phosphate-based high-entropy glass-ceramic solidified body prepared in Example 5 ( x =20 mol%) SEM image. Figure 3 The iron phosphate-based high-entropy glass-ceramic solidified body prepared in Example 5 ( x =20 mol%) SEM-EDS image. The results show that the phase composition of this high-entropy glass-ceramic solidified body consists of a ferrophosphate glass phase and a high-entropy monazite phase (La). 1 / 5 Ce 1 / 5 Nd 1 / 5 Sm 1 / 5 Gd 1 / 5 )PO4 composition; high-entropy monazite phase grains are relatively uniform in size and evenly distributed; multiple Ln Elements can be simultaneously and controllably dissolved in the high-entropy monazite phase.
Claims
1. A ferrophosphate-based high-entropy glass-ceramic solidified body, characterized in that: The glassy phase is Fe2O3-P2O5-B2O3-based glass, and the ceramic crystal phase is monazite, with five or more different substances dissolved in equal amounts in the monazite ceramic phase. Ln element.
2. The iron phosphate-based high-entropy glass-ceramic cured body as described in claim 1, characterized in that, The ceramic crystalline phase in the solidified body is only the high-entropy monazite ceramic phase, whose chemical formula is ( Ln 1 / n )PO4, in which Ln =La, Ce, Nd, Sm, Eu, Gd, Dy, Ho, Er, n It is an integer and 5≤ n ≤7, can be ( Ln 1 / 5 )PO4、( Ln 1 / 6 )PO4、( Ln 1 / 7 )PO4.
3. The iron phosphate-based high-entropy glass-ceramic solidified body as described in claim 1, characterized in that, Its preparation method is as follows: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error.] Ln Iron, boron, and phosphorus raw materials are mixed and ground in a set ratio, and then melted, nucleated, and crystallized in a high-temperature furnace in sequence before being cooled in the furnace to obtain an iron phosphate-based high-entropy glass-ceramic solidified body.
4. The iron phosphate-based high-entropy glass-ceramic cured body as described in claim 1, characterized in that, The general chemical formula of iron phosphate-based high-entropy glass-ceramic solidified bodies is (100- x ()( y Fe2O3-(90- y (P₂O₅-10B₂O₃)-0.5 x P2O5-( x / 2 n ()( Ln 2O3) (mol%), of which x The total molar ratio of lanthanide oxides ( x =0, 5, 10, 15, 20, 25, 30 mol%), y =15~35 mol%.
5. The iron phosphate-based high-entropy glass-ceramic solidified body as described in claim 3, characterized in that, The raw materials containing phosphorus are NH4H2PO4, the raw materials containing boron are H3BO3, the raw materials containing iron are Fe2O3, and the raw materials containing high-entropy lanthanide elements include La2O3, CeO2, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Dy2O3, Ho2O3, and Er2O3.
6. The iron phosphate-based high-entropy glass-ceramic solidified body as described in claim 3, characterized in that, The mixing method used is either dry ball milling or wet ball milling: raw materials containing phosphorus, boron, iron, and high-entropy elements, grinding media, and dispersant (wet ball milling) are added to a ball mill jar and ball milled to obtain a uniformly mixed material. The ball milling speed is 400 r / min and the ball milling time is 6~12 h.
7. The iron phosphate-based high-entropy glass-ceramic solidified body as described in claim 3, characterized in that, The sintering technique is a one-step melt heat treatment method, which uses either microwave sintering or traditional solid-state sintering. The uniformly mixed dry powder material is placed in a corundum crucible and heated to the melting temperature in a high-temperature furnace at a heating rate of 4℃ / min. After holding at this temperature for a certain time, it is cooled to the nucleation temperature at a rate of 4℃ / min and held at this temperature for a certain time. Then, it is heated to the crystallization temperature at a rate of 4℃ / min and held at this temperature for a certain time. Finally, it is cooled in the furnace to obtain the sample.
8. The iron phosphate-based high-entropy glass-ceramic solidified body as described in claim 6, characterized in that, The grinding media can be either zirconia balls or alumina balls, and the dispersant during wet ball milling can be either anhydrous ethanol or acetone.
9. The iron phosphate-based high-entropy glass-ceramic solidified body as described in claim 7, characterized in that, The melting temperature is 1200℃~1400℃, the nucleation temperature is 550℃~630℃, the crystallization temperature is 690℃~890℃, and the holding time is 60min~120min.