A lead borosilicate glass curing substrate, its preparation method and application

Abstract

This invention relates to the field of radioactive waste treatment, specifically to a lead borosilicate glass-cured substrate, its preparation method, and its application. The substrate, based on 100% oxide mass percentage, comprises the following components: PbO: 55%–75%, B2O3: 9%–16%, SiO2: 12%–20%; MgO: 1%–7%; TeO2: 0–11%; Al2O3: 0–5%; Li2O: 0–1%. The substrate of this invention can process complex source term radioactive waste at a relatively low melting temperature and exhibits good containment capacity. Specifically, the preparation steps are as follows: the substrate raw materials are mixed, melted at 900℃–1050℃, then cooled, and crushed to obtain a lead borosilicate glass-cured substrate. This substrate is then mixed with radioactive waste at an oxide mass ratio of (76–84):(16–24), held at 1000℃–1150℃, and then cooled to obtain a glass-cured body.

Description

Technical Field

[0001] This invention relates to the field of radioactive waste treatment, specifically to a lead borosilicate glass curing substrate, its preparation method, and its application. Background Technology

[0002] Nuclear energy, as a highly efficient and clean energy source, has become an important component of my country's energy system. Currently, the safe and sustainable utilization of nuclear energy mainly adopts the "closed-cycle" nuclear fuel technology route. However, the process of extracting useful nuclides during spent fuel reprocessing generates high-level radioactive waste liquid containing fission products, secondary actinides, and transuranium elements. This waste liquid has high specific activity, high heat release rate, long half-life, and high biological toxicity. Its safe and efficient treatment and disposal has become crucial to the sustainable development of nuclear power in my country.

[0003] Currently, the main treatment for high-level radioactive waste liquid is to solidify it and then carry out deep geological treatment. Among them, glass solidification is the only high-level radioactive waste liquid solidification technology that has been engineered and applied. At high temperature, the high-level radioactive waste liquid is evaporated, calcined and melted with glass substrate, and cast into a glass solidified body that is inclusive of various elements and has stable properties.

[0004] There are two common glass systems used for solidifying high-level radioactive waste: borosilicate glass and ferrophosphate glass. When borosilicate glass substrates are fused with high-level radioactive waste, the melting temperature is generally around 1150℃. Temperatures above 1000℃ generally cause the migration of volatile nuclides such as Tc / Re, Ru, and Cs, posing a challenge to downstream exhaust gas treatment. While the melting temperature of ferrophosphate glass can be lowered to around 1000℃, it has stringent requirements for glass composition and melting processes, and its long-term durability behavior is not yet clear, failing to effectively guarantee the safe solidification of key nuclides. Therefore, it currently remains largely in the laboratory research stage and is not widely used.

[0005] In view of this, it is indeed necessary to provide a technical solution to the above problems. Summary of the Invention

[0006] One of the objectives of this invention is to provide a lead borosilicate glass curing substrate that addresses the shortcomings of existing technologies. This substrate can process complex source term radioactive waste at a lower melting temperature and has a better containment rate.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A lead borosilicate glass curing substrate, comprising the following components by weight percentage of oxides:

[0009] PbO: 55%–75 wt%,

[0010] B2O3: 9%–16 wt%,

[0011] SiO2: 12%–20 wt%,

[0012] MgO: 1%–7 wt%

[0013] TeO2: 0–11 wt%,

[0014] Al2O3: 0–5 wt%,

[0015] Li2O: 0-1 wt%;

[0016] Among them, PbO, SiO2, MgO, and TeO2 are introduced in the form of oxides; B2O3 is introduced in the form of B2O3 or H3BO3; Al2O3 is introduced in the form of Al2O3, Al(OH)3, or Al2(CO3)3; and Li2O is introduced in the form of Li2CO3.

[0017] The second objective of this invention is to provide a method for preparing the lead borosilicate glass curing substrate described above, comprising the following steps: mixing PbO, B2O3, SiO2, MgO, TeO2, Al2O3, and Li2O according to the mass ratio of oxides to obtain a mixture; melting the mixture at 900℃~1050℃ to obtain a glass melt; pouring the glass melt into a mold and cooling it to obtain the lead borosilicate glass curing substrate.

[0018] Preferably, the melting time is 0.5 to 5 hours.

[0019] The third objective of this invention is to provide a method for treating radioactive waste, comprising the following steps: mixing granular or powdered glass-cured substrate with radioactive waste at an oxide mass ratio of (76-84):(16-24), heat-treating at 1000℃-1150℃ to obtain a glass melt, pouring the glass melt into a mold and cooling to obtain a glass-cured body, thereby completing the curing treatment of radioactive waste;

[0020] Wherein, the glass-cured substrate is the lead borosilicate glass-cured substrate described above or the lead borosilicate glass-cured substrate prepared by the preparation method of the lead borosilicate glass-cured substrate described above.

[0021] Preferably, the heat preservation time is 0.5 to 5 hours.

[0022] Preferably, the insulation temperature is higher than the melting temperature in the preparation of the glass-cured substrate, with a temperature difference of 100℃ to 200℃.

[0023] Preferably, the insulation temperature is 1050℃~1100℃.

[0024] Preferably, the mass ratio of the vitrified substrate to the radioactive waste is (78-82):(18-22).

[0025] The beneficial effects of this invention are as follows: The lead borosilicate glass curing substrate provided by this invention uses PbO, B2O3, and SiO2 to form a glass network, which serves as the basic framework of the glass curing body, ensuring that the maximum temperature during the glass curing process of radioactive waste does not exceed 1100℃. Simultaneously, a certain amount of MgO is added as a glass network modifier. Compared to single lead borosilicate glass curing bodies, the curing body of this invention has a higher waste containment rate, effectively containing various elements in radioactive waste, and can handle radioactive waste with complex source terms, rather than just a single nuclide. Furthermore, the addition of MgO also enhances the chemical stability and mechanical strength of the glass curing body. Attached Figure Description

[0026] Figure 1 These are actual images of the glass-cured bodies after waste treatment in Examples 1 and 2 of the present invention.

[0027] Figure 2 These are actual images of the glass-cured bodies after waste treatment in Examples 3 and 4 of the present invention.

[0028] Figure 3 These are actual images of the glass-cured bodies after waste treatment in Examples 5 and 6 of the present invention.

[0029] Figure 4 This is a photograph of the glass-cured body after waste treatment in Embodiment 7 of the present invention.

[0030] Figure 5 The images shown are actual photos of the glass-cured substrates of Comparative Examples 1 and 2 of this invention.

[0031] Figure 6 The image shows a physical picture of the glass-cured substrate and the glass-cured body of Comparative Example 3 of the present invention.

[0032] Figure 7 The XRD diffraction patterns of Examples 1 to 7 of this invention are shown.

[0033] Figure 8 The XRD diffraction patterns are for comparative examples 1 and 2. Detailed Implementation

[0034] To make the technical solution and advantages of the present invention clearer, the present invention and its beneficial effects will be described in further detail below, but the embodiments of the present invention are not limited thereto.

[0035] The "radioactive waste" mentioned in this invention refers to waste containing radioactive nuclides, mainly in liquid form.

[0036] The first aspect of the present invention provides a lead borosilicate glass curing substrate, comprising the following components based on 100% oxide by mass percentage: PbO: 55%–75 wt%, B2O3: 9%–16 wt%, SiO2: 12%–20 wt%; MgO: 1%–7 wt%; TeO2: 0–11 wt%; Al2O3: 0–5 wt%; Li2O: 0–1 wt%.

[0037] Among them, PbO, SiO2, MgO, and TeO2 are introduced in the form of oxides; B2O3 is introduced in the form of B2O3 or H3BO3; Al2O3 is introduced in the form of Al2O3, Al(OH)3, or Al2(CO3)3; and Li2O is introduced in the form of Li2CO3.

[0038] The glass-curing substrate of the present invention uses PbO, B2O3, and SiO2 as the main components to obtain a substrate with a low melting temperature. At the same time, the addition of MgO results in a glass-curing substrate with high containment capacity for various elements in radioactive waste, capable of treating waste liquids from complex sources, exhibiting higher waste containment capacity, and the treated waste has good chemical stability, which is beneficial to subsequent disposal requirements.

[0039] The mass of PbO added can be 55% to 75%, specifically 55% to 60%, 60% to 65%, 65% to 70%, or 70% to 75%. Preferably, the mass of PbO added is 55% to 66%.

[0040] The added mass of B2O3 can be 9% to 16%, specifically 9% to 10%, 10% to 12%, 12% to 14%, or 14% to 16%. Preferably, the added mass of B2O3 is 12% to 16%. For B2O3, H3BO3 can be added as a raw material during preparation, and it will appear as B2O3 in the lead borosilicate glass curing substrate after preparation.

[0041] The mass of SiO2 added can be 12% to 20%, specifically 12% to 14%, 14% to 16%, 16% to 18%, or 18% to 20%. Preferably, the mass of SiO2 added is 15% to 20%.

[0042] The glass-curing substrate developed based on PbO-B2O3-SiO2 has a lower melting temperature than lead-free glass-curing substrates. This reduces the migration of volatile nuclides when handling radioactive waste and makes the process easier.

[0043] In addition, some auxiliary additives are added to effectively enhance the glass network structure and chemical durability, forming a vitrified body with high containment capacity for various elements in radioactive waste and a low melting temperature. The inventors have found that using MgO as a glass network modifier is more effective in improving the stability and mechanical strength of the vitrified body. Research shows that an addition amount of 1% to 7% helps improve waste containment, while excessive amounts can lead to crystallization of the glass substrate. Specifically, the amount of MgO added can be 1% to 2%, 2% to 3%, 3% to 4%, 4% to 5%, 5% to 6%, or 6% to 7%. Preferably, the amount of MgO added is 3.5% to 6%.

[0044] Furthermore, this invention also discovers that the addition of TeO2, which simultaneously acts as a glass network former and a glass network modifier in the PbO-B2O3-SiO2 glass network, can further reduce the melting heat treatment temperature for waste inclusion in the glass substrate. Simultaneously, it works with MgO to suppress glass crystallization tendency, enhance glass stability, and improve the waste inclusion rate of the glass substrate. Preferably, the amount of TeO2 added can be 0% to 11%, specifically 0% to 2%, 2% to 4%, 4% to 6%, 6% to 8%, or 8% to 11%. More preferably, the amount of TeO2 added can be 0% to 7%.

[0045] Furthermore, the glass-cured substrate of the present invention can further incorporate Li2O as a glass network modifier. Controlling its content at a certain level can reduce the degree of polymerization of the glass network and help improve waste containment. Preferably, the amount of Li2O added is 0–1 wt%. For Li2O, Li2CO3 can be added as a raw material during preparation, and it will appear as Li2O in the lead-borosilicate glass-cured substrate after preparation.

[0046] Al2O3 can also be added to the system. Al2O3 is a glass network intermediate and can enhance the chemical stability of the glass-cured body. Preferably, the amount of Al2O3 added can be 0% to 5%. Al2O3 can be added as a raw material during preparation, using Al2O3, Al(OH)3, or Al2(CO3)3. After preparation, it appears as Al2O3 in the lead borosilicate glass-cured substrate.

[0047] Preferably, the lead borosilicate glass curing substrate comprises the following components, based on 100% by mass percentage of oxides:

[0048] PbO: 55% ~ 66wt%, B2O3: 12% ~ 16wt%, SiO2: 15% ~ 20wt%, MgO: 3.5 ~ 6wt%, TeO2: 0 ~ 7wt%, Al2O3: 0 ~ 5wt%, Li2O: 0 ~ 1wt%.

[0049] More preferably, the lead borosilicate glass curing substrate comprises the following components, based on 100% by mass percentage of oxides:

[0050] PbO: 55% ~ 66wt%, B2O3: 12% ~ 16wt%, SiO2: 15% ~ 20wt%, MgO: 3.5 ~ 6wt%, TeO2: 3 ~ 7wt%, Al2O3: 0% ~ 5wt%, Li2O: 0% ~ 1wt%.

[0051] Furthermore, the present invention also provides a method for preparing the lead borosilicate glass curing substrate, comprising the following steps: mixing PbO, B2O3, SiO2, MgO, TeO2, Al2O3 and Li2O according to the mass ratio to obtain a mixture; melting the mixture at 900℃~1050℃ to obtain a glass melt; pouring the glass melt into a mold and cooling it to obtain the lead borosilicate glass curing substrate.

[0052] Compared to the preparation of conventional borosilicate glass-cured substrates, the preparation method of the glass-cured substrate of the present invention can be carried out at a lower melting temperature, which can reduce the migration of volatile nuclides during subsequent radioactive waste treatment. At the same time, the resulting cured body also has good chemical stability, which is beneficial to the long-term disposal requirements of high-level radioactive waste glass-cured bodies.

[0053] Specifically, the melting temperature can be 900℃~950℃, 950℃~1000℃, or 1000℃~1050℃. The glass-cured substrate of the present invention can be melted at 900℃, which is a relatively low melting temperature, reducing the difficulty of the process and facilitating temperature control during subsequent waste treatment.

[0054] The melting time can be 0.5 to 5 hours. The specific melting time can be reasonably adjusted according to the content of each raw material and the melting temperature. However, it is important to avoid melting the time too short, which would affect the formation of the glass network and the chemical stability. At the same time, it is also important to avoid melting the temperature too long, which would result in excessive energy consumption and increased production costs.

[0055] The lead borosilicate glass-cured substrate obtained above is used for the treatment of radioactive waste, primarily for the treatment of waste liquid. To test the superiority of the lead borosilicate glass-cured substrate for treating radioactive waste, non-radioactive elements were used to simulate radioactive nuclides to prepare simulated high-level radioactive waste liquid. The main components included were La₂O₃: 12-14 wt%, MoO₃: 12-14 wt%, ZrO₂: 11-13 wt%, Nd₂O₃: 10-12 wt%, Na₂O: 10-12 wt%, Ce₂O₃: 6-7 wt%, Cs₂O: 6-7 wt%, and Fe₂O₃: [The text abruptly ends here, so the translation stops as well.] 4.5–5 wt%, BaO: 4.5–5 wt%, NiO: 3–3.5 wt%, SrO: 2–2.5 wt%, MnO: 1.5–2 wt%, Y2O3: 1–1.5 wt%, TeO2: 1–1.5 wt%, others: 3.5–4 wt%; wherein, other components include Cr2O3, Rb2O, Al2O3, K2O, CaO, CdO, Ag2O, SnO2, TiO2, MgO, and PbO with a content greater than 0.

[0056] Therefore, a third aspect of the present invention provides a method for treating radioactive waste, comprising the following steps: mixing granular or powdered vitrified substrate with radioactive waste at a mass ratio of (76-84):(16-24), holding the mixture at 1000℃-1150℃ to obtain a glass melt, pouring the glass melt into a mold and cooling it to obtain a vitrified body, thereby completing the solidification treatment of the radioactive waste; wherein, the vitrified substrate is the lead borosilicate glass substrate described above or the lead borosilicate glass substrate prepared by the above-described method for preparing the lead borosilicate glass substrate.

[0057] Thanks to the lower melting temperature during the preparation of the glass-cured substrate of this invention, when mixed with radioactive waste, it can be heat-preserved at a relatively low temperature of 1050℃ to 1100℃. Compared with the temperature of 1150℃ during conventional borosilicate glass processing, the melting temperature is lower, which can reduce the migration of volatile nuclides and reduce energy consumption; the waste containment rate can reach up to 24wt%, which is 50% higher than the containment rate of 16wt% of conventional borosilicate glass substrates.

[0058] Specifically, the mass ratio of the glass-cured substrate to radioactive waste by oxides includes, but is not limited to, 76:24, 77:23, 78:22, 79:21, 80:20, 81:19, 82:18, 83:17, and 84:16. Preferably, the mass ratio of the glass-cured substrate to radioactive waste is (78-82):(18-22). When the proportion of radioactive waste is 24%, the glass-cured substrate of this invention, after curing the waste, can still ensure a low total elemental leaching value and good chemical stability. However, if the proportion of waste is too high and the proportion of the glass-cured substrate is too low, the chemical stability of the cured glass will be poor, failing to meet long-term disposal requirements.

[0059] In some embodiments, the holding temperature is higher than the melting temperature during the preparation of the glass-cured substrate, with a temperature difference of 100℃ to 200℃. Setting the holding temperature relatively high ensures that the glass-cured substrate is completely molten, thereby better and more uniformly integrating waste into the glass system and ensuring the curing effect. Based on the melting temperature during the preparation of the glass-cured substrate, the holding temperature is preferably 1050℃ to 1100℃.

[0060] Of course, the heat preservation time also needs to be controlled during the process. The heat preservation time should be controlled to 0.5 to 5 hours. On the one hand, this can avoid the time being too short, which would prevent all the waste from being completely solidified. On the other hand, it can also avoid the time being too long, which would increase energy consumption and increase the migration of volatile nuclides.

[0061] The present invention and its beneficial effects will be further described in detail below with reference to specific embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0062] Example 1

[0063] A lead borosilicate glass curing substrate, based on 100% oxide by mass percentage, comprises the following components: PbO: 55wt%, B2O3: 14wt%, SiO2: 15wt%, MgO: 5wt%, TeO2: 11wt%, Al2O3: 0wt%, Li2O: 0wt%; wherein, B2O3 is introduced as a raw material in the form of H3BO3.

[0064] The preparation method of this lead borosilicate glass cured substrate is as follows:

[0065] Taking 100g of the mixture as a reference, PbO, B2O3, SiO2, MgO, and TeO2 are mixed evenly according to the above mass ratio to obtain a mixture. The mixture is placed in a 100mL corundum crucible and melted in a muffle furnace at 950℃ for 1 hour to obtain a glass melt. The crucible is quickly removed and the glass melt is poured into a metal mold. After cooling, it is crushed to obtain a lead borosilicate glass cured substrate.

[0066] The obtained lead borosilicate glass-cured substrate was used to treat simulated high-level radioactive waste. The treatment method was as follows: granular or powdered glass-cured substrate and radioactive waste (the simulated high-level radioactive waste) were mixed and weighed at an oxide mass ratio of 78:22. 100g of the total amount was placed in a 100mL corundum crucible and heated in a muffle furnace at 1100℃ for 1 hour to obtain a glass melt. The glass melt was poured into a metal mold and cooled to obtain a glass-cured body, thus completing the curing process.

[0067] Example 2

[0068] A lead borosilicate glass curing substrate, based on 100% oxide by mass, comprises the following components: PbO: 75wt%, B2O3: 9wt%, SiO2: 12wt%, MgO: 4wt%, TeO2: 0wt%, Al2O3: 0wt%, Li2O: 0wt%; wherein, B2O3 is introduced as a raw material in the form of H3BO3.

[0069] The preparation method of this lead borosilicate glass cured substrate is as follows:

[0070] Taking 100g of the mixture as a reference, PbO, B2O3, SiO2, and MgO are mixed evenly according to the above mass ratio to obtain a mixture. The mixture is placed in a 100mL corundum crucible and melted in a muffle furnace at 1050℃ for 1 hour to obtain a glass melt. The crucible is quickly removed and the glass melt is poured into a metal mold. After cooling, it is crushed to obtain a lead borosilicate glass cured substrate.

[0071] The obtained lead borosilicate glass-cured substrate was used to treat simulated high-level radioactive waste. The treatment method was as follows: granular or powdered glass-cured substrate and radioactive waste were mixed and weighed at an oxide mass ratio of 84:16. 100g of the total amount was placed in a 100mL corundum crucible and heated in a muffle furnace at 1150℃ for 1 hour to obtain a glass melt. The glass melt was poured into a metal mold and cooled to obtain a glass-cured body, thus completing the curing process.

[0072] Example 3

[0073] A lead borosilicate glass curing substrate, based on 100% oxide by mass percentage, comprises the following components: PbO: 62wt%, B2O3: 16wt%, SiO2: 16.5wt%, MgO: 5.5wt%, TeO2: 0wt%, Al2O3: 0wt%, Li2O: 0wt%; wherein, B2O3 is introduced as a raw material in the form of H3BO3.

[0074] The preparation method of this lead borosilicate glass cured substrate is as follows:

[0075] Taking 100g of the mixture as a reference, PbO, B2O3, SiO2 and MgO are mixed evenly according to the above mass ratio to obtain a mixture. The mixture is placed in a 100mL corundum crucible and melted in a muffle furnace at 900℃ for 1 hour to obtain a glass melt. The crucible is quickly removed and the glass melt is poured into a metal mold. After cooling, it is crushed to obtain a lead borosilicate glass cured substrate.

[0076] The obtained lead borosilicate glass-cured substrate was used to treat simulated high-level radioactive waste. The treatment method was as follows: granular or powdered glass-cured substrate and radioactive waste were mixed and weighed at an oxide mass ratio of 80:20. 100g of the total amount was placed in a 100mL corundum crucible and heated in a muffle furnace at 1050℃ for 1 hour to obtain a glass melt. The glass melt was poured into a metal mold and cooled to obtain a glass-cured body, thus completing the curing process.

[0077] Example 4

[0078] A lead borosilicate glass curing substrate, based on 100% oxide by mass, comprises the following components: PbO: 61.3 wt%, B2O3: 12.91 wt%, SiO2: 20 wt%, MgO: 5.79 wt%, TeO2: 0 wt%, Al2O3: 0 wt%, Li2O: 0 wt%; wherein, B2O3 is introduced as a raw material in the form of H3BO3.

[0079] The preparation method of this lead borosilicate glass cured substrate is as follows:

[0080] Taking 100g of the mixture as a reference, PbO, B2O3, SiO2, and MgO are mixed evenly according to the above mass ratio to obtain a mixture. The mixture is placed in a 100mL corundum crucible and melted in a muffle furnace at 950℃ for 1 hour to obtain a glass melt. The crucible is quickly removed and the glass melt is poured into a metal mold. After cooling, it is broken to obtain a lead borosilicate glass cured substrate.

[0081] The obtained lead borosilicate glass-cured substrate was used to treat simulated high-level radioactive waste. The treatment method was as follows: granular or powdered glass-cured substrate and radioactive waste were mixed and weighed at an oxide mass ratio of 82:18. 100g of the total amount was placed in a 100mL corundum crucible and heated in a muffle furnace at 1100℃ for 1 hour to obtain a glass melt. The glass melt was poured into a metal mold and cooled to obtain a glass-cured body, thus completing the curing process.

[0082] Example 5

[0083] A lead borosilicate glass curing substrate, based on 100% oxide by mass percentage, comprises the following components: PbO: 61.2 wt%, B2O3: 12.72 wt%, SiO2: 15.37 wt%, MgO: 5.52 wt%, TeO2: 0 wt%, Al2O3: 4.65 wt%, Li2O: 0.54 wt%; wherein, B2O3 is introduced as a raw material in the form of H3BO3, Al2O3 is introduced as a raw material in the form of Al(OH)3, and Li2O is introduced as a raw material in the form of Li2CO3.

[0084] The preparation method of this lead borosilicate glass cured substrate is as follows:

[0085] Taking 100g of the mixture as a reference, PbO, B2O3, SiO2, MgO, Al2O3, and Li2O are mixed evenly according to the above mass ratio to obtain a mixture. The mixture is placed in a 100mL corundum crucible and melted in a muffle furnace at 1000℃ for 1 hour to obtain a glass melt. The crucible is quickly removed and the glass melt is poured into a metal mold. After cooling, it is broken to obtain a lead borosilicate glass cured substrate.

[0086] The obtained lead borosilicate glass-cured substrate was used to treat simulated high-level radioactive waste. The treatment method was as follows: granular or powdered glass-cured substrate and radioactive waste were mixed and weighed at an oxide mass ratio of 82:18. 100g of the total amount was placed in a 100mL corundum crucible and heated in a muffle furnace at 1100℃ for 1 hour to obtain a glass melt. The glass melt was poured into a metal mold and cooled to obtain a glass-cured body, thus completing the curing process.

[0087] For the rest, please refer to Example 1, which will not be repeated here.

[0088] Example 6

[0089] A lead borosilicate glass curing substrate, comprising the following components by 100% oxide mass percentage: PbO: 59.13wt%, B2O3: 14.51wt%, SiO2: 15.92wt%, MgO: 3.5wt%, TeO2: 6.94wt%, Al2O3: 0wt%, Li2O: 0wt%; wherein, B2O3 is introduced as a raw material in the form of H3BO3.

[0090] The preparation method of this lead borosilicate glass cured substrate is as follows:

[0091] Taking 100g of the mixture as a reference, PbO, B2O3, SiO2, MgO, and TeO2 are mixed evenly according to the above mass ratio to obtain a mixture. The mixture is placed in a 100mL corundum crucible and melted in a muffle furnace at 900℃ for 1 hour to obtain a glass melt. The crucible is quickly removed and the glass melt is poured into a metal mold. After cooling, it is crushed to obtain a lead borosilicate glass cured substrate.

[0092] The obtained lead borosilicate glass-cured substrate was used to treat simulated high-level radioactive waste. The treatment method was as follows: granular or powdered glass-cured substrate and radioactive waste were mixed and weighed at an oxide mass ratio of 84:16. 100g of the total amount was placed in a 100mL corundum crucible and heated in a muffle furnace at 1000℃ for 1.5h to obtain a glass melt. The glass melt was poured into a metal mold and cooled to obtain a glass-cured body, thus completing the curing process.

[0093] Example 7

[0094] Unlike Example 6, the method for treating the simulated high-level radioactive waste liquid is different. The obtained lead borosilicate glass-cured substrate is used to treat the simulated high-level radioactive waste liquid. The treatment method is as follows: the granular or powdered glass-cured substrate and radioactive waste are mixed and weighed at an oxide mass ratio of 76:24. 100g of the total amount is placed in a 100mL corundum crucible and heated in a 1100°C muffle furnace for 1.5h to obtain a glass melt. The glass melt is poured into a metal mold and cooled to obtain a glass-cured body, thus completing the curing process.

[0095] For the rest, please refer to Example 6, which will not be repeated here.

[0096] Comparative Example 1

[0097] A lead borosilicate glass curing substrate, based on 100% oxide by mass percentage, comprises the following components: PbO: 68.5 wt%, B2O3: 10.38 wt%, SiO2: 12.64 wt%, MgO: 8.48 wt%, TeO2: 0 wt%, Al2O3: 0 wt%, Li2O: 0 wt%; wherein, B2O3 is introduced as a raw material in the form of H3BO3.

[0098] The preparation method of this lead borosilicate glass cured substrate is as follows:

[0099] Taking 100g of the mixture as a reference, PbO, B2O3, SiO2 and MgO are mixed evenly according to the above mass ratio to obtain a mixture. The mixture is placed in a 100mL corundum crucible and melted in a muffle furnace at 1050℃ for 1h to obtain a glass melt. The crucible is quickly removed and the glass melt is poured into a metal mold. After cooling, it is crushed to obtain a lead borosilicate glass cured substrate.

[0100] Comparative Example 2

[0101] A borosilicate glass curing substrate, based on 100% oxide by mass, comprises the following components: SiO2: 51.5 wt%, B2O3: 16.0 wt%, Al2O3: 6.5 wt%, Na2O: 10.0 wt%, CaO: 4.0 wt%, Li2O: 2.0 wt%, ZnO: 2.5 wt%, and ZrO2: 7.5 wt%. Wherein SiO2, Al2O3, ZnO, and ZrO2 are introduced in oxide form, B2O3 is introduced in H2BO3 form, Na2O is introduced in Na2CO3 form, CaO is introduced in CaCO3 form, and Li2O is introduced in Li2CO3 form.

[0102] The preparation method of the borosilicate glass-cured substrate is as follows: Mix all the raw materials according to the above mass ratio, mix them thoroughly and evenly, place them in a 100mL corundum crucible, transfer them to a muffle furnace at 1050℃ and keep them warm for 1.5h, then quickly remove the crucible and pour the glass melt onto a metal mold. After cooling, the glass-cured substrate is obtained.

[0103] Comparative Example 3

[0104] A lead borosilicate glass curing substrate, based on 100% oxide by mass, comprises the following components: PbO: 70wt%, B2O3: 15wt%, SiO2: 15wt%, MgO: 0wt%, TeO2: 0wt%, Al2O3: 0wt%, Li2O: 0wt%; wherein, B2O3 is introduced as a raw material in the form of H3BO3.

[0105] The preparation method of this lead borosilicate glass cured substrate is as follows:

[0106] Using 100g of the mixture as a reference, PbO, B2O3, and SiO2 are mixed evenly according to the above mass ratio to obtain a mixture. The mixture is placed in a 100mL corundum crucible and melted in a muffle furnace at 1050℃ for 1 hour to obtain a glass melt. The crucible is quickly removed and the glass melt is poured into a metal mold. After cooling, it is broken to obtain a lead borosilicate glass cured substrate.

[0107] The obtained lead borosilicate glass-cured substrate was used to treat simulated high-level radioactive waste. The treatment method was as follows: granular or powdered glass-cured substrate and radioactive waste were mixed and weighed at an oxide mass ratio of 84:16. 100g of the total amount was placed in a 100mL corundum crucible and heated in a muffle furnace at 1150℃ for 1.5h to obtain a glass melt. The glass melt was poured into a metal mold and cooled to obtain a glass-cured body, thus completing the curing process.

[0108] The glass-cured bodies obtained in Examples 1-7 above were evaluated using the internationally recognized product consistency test (PCT) (ASTM C 1285-02) to assess the chemical stability of the glass-cured bodies (single element leaching value ≤ 2 g / m³). 2 The elements detected in the leaching process include: Na, Mg, Al, Ca, Ti, Cr, Fe, Ni, Rb, Sr, Y, Zr, Mo, Ag, Cd, Sn, Te, Cs, Ba, La, Ce, Nd, Pb, K, Mn, B, and Si.

[0109] The test results are shown in Table 1 and Figures 1-8 .

[0110] Table 1 Results of Chemical Stability Tests

[0111] Vitrified substrates: radioactive waste <![CDATA[Total leaching value of element PCT-7 (g / m 2 )]]> Example 1 78：22 0.1224 Example 2 84：16 0.0586 Example 3 80：20 0.4147 Example 4 82：18 0.0870 Example 5 82：18 0.3280 Example 6 84：16 0.0449 Example 7 76：24 0.0719 Comparative Example 1 / / Comparative Example 2 / / Comparative Example 3 84：16 /

[0112] Note: Total leaching value is the sum of the leaching values ​​of individual elements such as Na, Mg, Al, Ca, and Ti.

[0113] From Table 1 above and Figures 1-8 As can be seen from the XRD diffraction pattern, the glass-cured body obtained by this invention exhibits typical amorphous peaks, consistent with the actual sample, proving the formation of a homogeneous glass. However, compared to the sample in Comparative Example 1, it was found that excessive MgO could not form a glass substrate at a melting temperature of 1050℃; similarly, compared to Comparative Example 2, conventional lead-free borosilicate glass substrates also could not form a homogeneous glass at a melting temperature of 1050℃, requiring even higher temperatures, which is also corroborated by their XRD diffraction patterns.

[0114] As can be seen from the elemental leaching results of Examples 1-7, the glass-curing substrate and glass-cured body of the present invention can be manufactured at relatively low melting temperatures, and the inclusion rate can still reach more than 16 wt% for radioactive waste with complex source terms, and can reach 24 wt% under preferred conditions. Moreover, the elemental leaching amount is low, far less than the specified single element leaching value ≤2 g / m³. 2 It is evident that the glass-cured body of the present invention has good chemical stability.

[0115] As can be seen from the comparison of Examples 3 and 6 and Comparative Example 3, using MgO as a network modifier for lead borosilicate glass, compared with PbO-B2O3-SiO2 ternary base glass, the addition of MgO is more conducive to improving the waste containment rate and the total element leaching rate. Moreover, when MgO and TeO2 are used together as an auxiliary agent, the melting temperature of the glass solidification body can be further reduced, the waste containment rate can be improved, and the element leaching can be more effectively suppressed. This is mainly because TeO2 can assist MgO to play an effective role, avoiding element leaching to a greater extent and resulting in a higher waste containment rate. However, the inventors also found through investigation that when the MgO content is high, the crystallization of the glass substrate cannot be effectively controlled, which will lead to the glass substrate failing to form a glass body, as shown in the experimental results of Comparative Example 1. When the MgO content is 0, as shown in the experimental results of Comparative Example 3 (see Figure 6 The glass substrate exhibits a glassy luster, but at a waste inclusion rate of 16 wt%, the cured body shows obvious unmelted material, indicating poor melting effect. Preferably, the amount of MgO added is controlled between 3.5% and 6%, resulting in better waste inclusion rate and chemical stability of the glass cured body.

[0116] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments described above, and any obvious improvements, substitutions, or modifications made by those skilled in the art based on the present invention are within the scope of protection of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A lead borosilicate glass curing substrate, characterized in that, Based on 100% by mass of oxides, it includes the following components: PbO: 55%–75 wt%, B2O3: 9%–16 wt%, SiO2: 12%–20 wt%, MgO: 1%–7 wt% TeO2: 0–11 wt%, Al2O3: 0–5 wt%, Li2O: 0-1 wt%; Among them, PbO, SiO2, MgO, and TeO2 are introduced in the form of oxides; B2O3 is introduced in the form of B2O3 or H3BO3; Al2O3 is introduced in the form of Al2O3, Al(OH)3, or Al2(CO3)3; and Li2O is introduced in the form of Li2CO3.

2. The lead borosilicate glass curing substrate according to claim 1, characterized in that, Based on 100% by mass of oxides, it includes the following components: PbO: 55%–66 wt%, B2O3: 12%–16 wt%, SiO2: 15%–20 wt%, MgO: 3.5–6 wt%. TeO2: 0-7wt%, Al2O3: 0–5 wt%, Li2O: 0–1 wt%.

3. A method for preparing a lead borosilicate glass curing substrate as described in claim 1 or 2, characterized in that, Includes the following steps: PbO, B2O3, SiO2, MgO, TeO2, Al2O3, and Li2O are mixed according to the mass ratio of oxides to obtain a mixture. The mixture is then melted at 900℃ to 1050℃ to obtain a glass melt. The glass melt is poured into a mold and cooled to obtain a lead borosilicate glass curing substrate.

4. The method for preparing the lead borosilicate glass curing substrate according to claim 3, characterized in that, The melting time is 0.5 to 5 hours.

5. A method for treating radioactive waste, characterized in that, Includes the following steps: A granular or powdered glass curing substrate is mixed with radioactive waste at an oxide mass ratio of (76-84):(16-24), and then kept at 1000℃-1150℃ to obtain a glass melt. The glass melt is poured into a mold and cooled to obtain a glass curing body, thus completing the curing treatment of radioactive waste. Wherein, the glass-cured substrate is the lead borosilicate glass-cured substrate according to any one of claims 1 to 2 or the lead borosilicate glass-cured substrate prepared by the preparation method of the lead borosilicate glass-cured substrate according to any one of claims 3 to 4.

6. The method for treating radioactive waste according to claim 5, characterized in that, The heat preservation time is 0.5 to 5 hours.

7. The method for treating radioactive waste according to claim 5 or 6, characterized in that, The insulation temperature is higher than the melting temperature in the preparation of the glass-cured substrate, with a temperature difference of 100℃~200℃.

8. The method for treating radioactive waste according to claim 7, characterized in that, The insulation temperature is 1050℃~1100℃.

9. The method for treating radioactive waste according to claim 5, characterized in that, The mass ratio of the vitrified substrate to radioactive waste was (78–82):(18–22).

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