Lead borosilicate glass curing base material as well as preparation method and application thereof

Abstract

The invention relates to the field of radioactive waste treatment, in particular to a lead borosilicate glass curing base material and a preparation method and application thereof.The base material is prepared from, by mass, 55%-75% of PbO, 9%-16% of B2O3 and 12%-20% of SiO2, 1%-7% of MgO; 0 to 11% of TeO2; 0 to 5 percent of Al2O3; and 0 to 1% of Li2O. The base material disclosed by the invention can be used for treating radioactive wastes with complex source items at a relatively low melting temperature, and has a relatively good inclusion rate. Specifically, the preparation method comprises the following steps: mixing base material raw materials, melting at 900-1050 DEG C, then cooling, crushing to obtain a lead borosilicate glass solidified base material, then mixing the lead borosilicate glass solidified base material with radioactive waste according to the mass ratio of oxides of (76-84): (16-24), preserving heat at 1000-1150 DEG C, and then cooling to obtain a glass solidified body.

Description

Technical Field

[0001] The invention relates to the field of radioactive waste treatment, and in particular to a lead borosilicate glass solidification substrate and a preparation method and application thereof. Background Art

[0002] As an efficient and clean energy, nuclear energy has become an important part of my country's energy system. At present, the safe and sustainable use of nuclear energy is mainly achieved by the nuclear fuel "closed cycle" technology route. However, in the process of extracting useful nuclides from spent fuel reprocessing, high-level waste liquid containing fission products, minor actinides and transuranic elements will be produced. This waste liquid has high radioactive specific activity, high heat release rate, long half-life and high biological toxicity. Its safe and efficient treatment and disposal has become the key to determining the sustainable development of my country's nuclear power.

[0003] At present, the main method of disposing of high-level radioactive liquid waste is to solidify it and then dispose of it in deep geological conditions. Among them, glass solidification is the only high-level radioactive liquid waste solidification technology that has been applied in engineering. At high temperature, the high-level radioactive liquid waste is evaporated, calcined and melted with a glass substrate, and then cast to form a glass solid body that has a wide tolerance for various elements and stable properties.

[0004] There are two types of glass systems commonly used for solidifying high-level radioactive liquid waste, namely borosilicate glass and iron phosphate glass. When the borosilicate glass substrate is melted with high-level radioactive liquid waste, the melting temperature is generally around 1150°C. Temperatures above 1000°C generally cause the migration of volatile nuclides such as Tc / Re, Ru, and Cs, posing certain challenges to the back-end exhaust gas treatment. Although the melting temperature of iron phosphate glass can be reduced to around ~1000°C, it has more stringent requirements on the glass composition and melting process, and its long-term durability behavior has not yet been clarified, and it cannot effectively guarantee the safe solidification of key nuclides. Therefore, it is currently mostly in the laboratory research stage and has not been 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 purposes of the present invention is to provide a lead borosilicate glass solidified substrate to address the deficiencies of the prior art, which substrate can process complex source radioactive waste at a lower melting temperature and has a better inclusion rate.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A lead borosilicate glass solidified substrate, calculated by oxide mass percentage 100%, comprises the following components:

[0009] PbO: 55%~75wt%,

[0010] B2O3: 9%~16wt%,

[0011] SiO2: 12%~20wt%,

[0012] MgO: 1%~7wt%,

[0013] TeO2: 0~11wt%

[0014] Al2O3: 0~5wt%

[0015] Li2O: 0-1wt%;

[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 object of the present invention is to provide a method for preparing the above-mentioned lead borosilicate glass solidified substrate, comprising the following steps: mixing PbO, B2O3, SiO2, MgO, TeO2, Al2O3, and Li2O according to the mass proportion of the oxides to obtain a mixture; melting the mixture at 900°C to 1050°C to obtain a glass melt, pouring the glass melt into a mold and cooling it to obtain a lead borosilicate glass solidified substrate.

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

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

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

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

[0022] Preferably, the insulation temperature is greater than the melting temperature in the preparation of the glass solidification substrate, and the temperature difference is 100°C to 200°C.

[0023] Preferably, the insulation temperature is 1050°C to 1100°C.

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

[0025] The beneficial effects of the present invention are as follows: the lead borosilicate glass solidification substrate provided by the present invention uses PbO, B2O3, and SiO2 to form a glass network as the basic skeleton of the glass solidification body, so that the maximum temperature of the radioactive waste glass solidification process does not exceed 1100°C. At the same time, a certain amount of MgO is added as a glass network modifier. Compared with the single lead borosilicate glass solidification body, the solidification body of the present invention has a higher waste inclusion rate, can effectively include various elements in the radioactive waste, can treat radioactive waste with complex source items, rather than just a certain nuclide, and the addition of MgO also enhances the chemical stability and mechanical strength of the glass solidification body. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a physical picture of the glass solidified body after waste is treated in Example 1 and Example 2 of the present invention.

[0027] Figure 2 This is a physical picture of the glass solidified body after waste is treated in Examples 3 and 4 of the present invention.

[0028] Figure 3 This is a physical picture of the glass solidified body after waste treatment in Examples 5 and 6 of the present invention.

[0029] Figure 4 This is a physical picture of the glass solidified body after waste treatment in Example 7 of the present invention.

[0030] Figure 5 This is a physical picture of the glass-cured substrate of Comparative Example 1 and Comparative Example 2 of the present invention.

[0031] Figure 6 This is 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 the present invention are shown in FIG.

[0033] Figure 8 It is the XRD diffraction spectrum of comparative examples 1-2. DETAILED DESCRIPTION

[0034] In order to make the technical solutions and advantages of the present invention more clear, the present invention and its beneficial effects are described in further detail below, but the embodiments of the present invention are not limited thereto.

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

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

[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-solidified substrate of the present invention uses PbO, B2O3 and SiO2 as the main components of the glass-solidified substrate, and can obtain a substrate with a lower melting temperature. By adding MgO at the same time, the formed glass-solidified substrate has a higher inclusion rate for various elements in radioactive waste, can treat waste liquid with complex sources, has a higher waste inclusion rate, and the treated waste has good chemical stability, which is beneficial to later disposal requirements.

[0039] The added mass of PbO may be 55% to 75%, specifically 55% to 60%, 60% to 65%, 65% to 70% or 70% to 75%. Preferably, the added mass of PbO 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%. B2O3 can be added as H3BO3 as a raw material during preparation, and after preparation, it appears as B2O3 in the lead borosilicate glass solidified substrate.

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

[0042] The glass-solidified substrate developed based on PbO-B2O3-SiO2 has a lower melting temperature than the lead-free glass-solidified substrate. The lead-containing substrate can reduce the migration of volatile nuclides when treating radioactive waste and has a lower process difficulty.

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

[0044] In addition, the present invention also found that the addition of TeO2 can simultaneously act as a glass network former and a glass network modifier in the PbO-B2O3-SiO2 glass network, and while further reducing the glass substrate waste melting heat treatment temperature, it can work together with MgO to inhibit the glass crystallization tendency, enhance the glass stability, and improve the glass substrate waste inclusion rate. Preferably, the addition amount of TeO2 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 addition amount of TeO2 can be 0% to 7%.

[0045] In addition, the glass solidification substrate of the present invention can further add Li2O as a glass network modifier, which can reduce the glass network polymerization degree under a certain content and help improve the waste inclusion rate. Preferably, the amount of Li2O added is 0-1wt%. For Li2O, Li2CO3 can be added as a raw material during preparation, and after preparation, it appears as Li2O in the lead borosilicate glass solidification substrate.

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

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

[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, based on 100% by mass of oxide, the lead borosilicate glass solidified substrate comprises the following components:

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

[0051] In addition, the present invention also provides a method for preparing the lead borosilicate glass solidified substrate, comprising the following steps: mixing PbO, B2O3, SiO2, MgO, TeO2, Al2O3 and Li2O according to their mass proportions to obtain a mixture; melting the mixture at 900°C to 1050°C to obtain a glass melt, pouring the glass melt into a mold and cooling it to obtain a lead borosilicate glass solidified substrate.

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

[0053] Specifically, the melting temperature may be 900° C. to 950° C., 950° C. to 1000° C., or 1000° C. to 1050° C. The glass-solidified substrate of the present invention can be melted at 900° C. The melting temperature is relatively low, which reduces the process difficulty and helps to control the temperature during subsequent waste treatment.

[0054] The melting time can be 0.5 to 5 hours. The specific melting time can be reasonably adjusted in combination with the content of each raw material and the melting temperature, but it should be avoided that the melting time is too short, which affects the formation of the glass network and the chemical stability, and the melting temperature is too long, which causes excessive energy consumption and increases the production cost.

[0055] The lead borosilicate glass solidified substrate obtained above is used for the treatment of radioactive waste, mainly for the treatment of waste liquid. In order to test the superiority of the lead borosilicate glass solidified substrate of the present invention in treating radioactive waste, non-radioactive elements are used to simulate and replace radioactive nuclides to prepare simulated high-level waste liquid, which mainly contains the following components: La2O3: 12-14wt%, MoO3: 12-14wt%, ZrO2: 11-13wt%, Nd2O3: 10-12wt%, Na2O: 10-12wt%, Ce2O3: 6-7wt%, Cs2O: 6-7wt%, Fe2O3: 4.5~5wt%, BaO: 4.5~5wt%, NiO: 3~3.5wt%, SrO: 2~2.5wt%, MnO: 1.5~2wt%, Y2O3: 1~1.5wt%, TeO2: 1~1.5wt%, others: 3.5~4wt%; among which other components include Cr2O3, Rb2O, Al2O3, K2O, CaO, CdO, Ag2O, SnO2, TiO2, MgO, and PbO with a content greater than 0.

[0056] To this end, the third aspect of the present invention provides a method for treating radioactive waste, comprising the following steps: mixing a granular or powdered glass-solidified substrate with radioactive waste in a mass ratio of (76-84):(16-24), keeping warm at 1000°C-1150°C to obtain a glass melt, pouring the glass melt into a mold and cooling it to obtain a glass solidified body, thereby completing the solidification treatment of the radioactive waste; wherein the glass-solidified substrate is the lead-borosilicate glass-solidified substrate described above or the lead-borosilicate glass-solidified substrate obtained by the preparation method of the lead-borosilicate glass-solidified substrate described above.

[0057] Thanks to the lower melting temperature in the preparation process of the glass-solidified substrate of the present invention, when mixed with radioactive waste, it can be heat-insulated at a relatively low temperature of 1050°C to 1100°C. Compared with the temperature of 1150°C during conventional borosilicate glass treatment, 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 the radioactive waste by oxide includes but is not limited to: 76:24, 77:23, 78:22, 79:21, 80:20, 81:19, 82:18, 83:17, 84:16. Preferably, the mass ratio of the glass-cured substrate to the radioactive waste is (78-82):(18-22). When the proportion of radioactive waste is 24%, after the glass-cured substrate of the present invention solidifies the waste, it can still ensure that the total value of element leaching is low and the chemical stability is good. If the proportion of waste is too high and the proportion of the glass-cured substrate is too low, the chemical stability of the glass-cured body will be poor and cannot meet the long-term disposal requirements.

[0059] In some embodiments, the insulation temperature is greater than the melting temperature in the preparation of the glass solidification substrate, and the temperature difference is 100°C to 200°C. Setting the insulation temperature relatively high can ensure that the glass solidification substrate is completely in a molten state, thereby better integrating the waste into the glass system evenly and ensuring the solidification effect. According to the melting temperature in the preparation of the glass solidification substrate, the insulation temperature is preferably 1050°C to 1100°C.

[0060] Of course, the insulation time also needs to be controlled during the treatment process. The insulation time should be controlled to 0.5 to 5 hours. On the one hand, it can avoid the time being too short and not being able to completely solidify all the waste; on the other hand, it can also avoid the time being too long and increasing energy consumption and the migration of volatile nuclides.

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

[0062] Example 1

[0063] A lead borosilicate glass solidified substrate comprises the following components, calculated based on 100% oxide mass percentage: 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 the lead borosilicate glass solidified substrate is as follows:

[0065] Taking 100 g of the mixture as a reference, PbO, B2O3, SiO2, MgO and TeO2 are uniformly mixed according to the above mass proportions to obtain a mixture; the mixture is placed in a 100 mL corundum crucible, moved to a 950°C muffle furnace and melted for 1 hour to obtain a glass melt, the crucible is quickly taken out and the glass melt is poured into a metal mold, and then crushed after cooling to obtain a lead borosilicate glass solidified substrate.

[0066] The obtained lead borosilicate glass solidification substrate is used to treat simulated high-level radioactive liquid waste. The treatment method is: the granular or powdered glass solidification substrate and the radioactive waste (the above-mentioned simulated high-level radioactive liquid waste) are weighed in an oxide mass ratio of 78:22, a total amount of 100 g is weighed and placed in a 100 mL corundum crucible, and moved to a 1100°C muffle furnace for insulation treatment for 1 hour to obtain a glass melt, the glass melt is poured into a metal mold, and a glass solid body is obtained after cooling, thereby completing the solidification treatment.

[0067] Example 2

[0068] A lead borosilicate glass solidified substrate comprises the following components, calculated based on 100% oxide mass percentage: 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 the lead borosilicate glass solidified substrate is as follows:

[0070] Taking 100 g of the mixture as a reference, PbO, B2O3, SiO2, and MgO are uniformly mixed according to the above-mentioned mass proportions to obtain a mixture; the mixture is placed in a 100 mL corundum crucible, moved to a 1050°C muffle furnace and melted for 1 hour to obtain a glass melt, the crucible is quickly taken out and the glass melt is poured into a metal mold, and then crushed after cooling to obtain a lead borosilicate glass solidified substrate.

[0071] The obtained lead borosilicate glass solidification substrate is used to treat simulated high-level radioactive liquid waste. The treatment method is: the granular or powdered glass solidification substrate and the radioactive waste are weighed in an oxide mass ratio of 84:16, a total amount of 100 g is weighed and placed in a 100 mL corundum crucible, and moved to a 1150°C muffle furnace for insulation treatment for 1 hour to obtain a glass melt, the glass melt is poured into a metal mold, and a glass solid body is obtained after cooling, completing the solidification treatment.

[0072] Example 3

[0073] A lead borosilicate glass solidified substrate comprises the following components based on 100% oxide mass percentage: 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 the lead borosilicate glass solidified substrate is as follows:

[0075] Taking 100 g of the mixture as a reference, PbO, B2O3, SiO2 and MgO are uniformly mixed according to the above mass proportions to obtain a mixture; the mixture is placed in a 100 mL corundum crucible, moved to a 900°C muffle furnace and melted for 1 hour to obtain a glass melt, the crucible is quickly taken out and the glass melt is poured into a metal mold, and then crushed after cooling to obtain a lead borosilicate glass solidified substrate.

[0076] The obtained lead borosilicate glass solidification substrate is used to treat simulated high-level radioactive liquid waste. The treatment method is: the granular or powdered glass solidification substrate and the radioactive waste are weighed in an oxide mass ratio of 80:20, a total amount of 100 g is weighed and placed in a 100 mL corundum crucible, and moved to a 1050°C muffle furnace for insulation treatment for 1 hour to obtain a glass melt, the glass melt is poured into a metal mold, and a glass solidification body is obtained after cooling, completing the solidification treatment.

[0077] Example 4

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

[0079] The preparation method of the lead borosilicate glass solidified substrate is as follows:

[0080] Taking 100 g of the mixture as a reference, PbO, B2O3, SiO2, and MgO are uniformly mixed according to the above-mentioned mass proportions to obtain a mixture; the mixture is placed in a 100 mL corundum crucible, transferred to a 950°C muffle furnace and melted for 1 hour to obtain a glass melt, the crucible is quickly taken out and the glass melt is poured into a metal mold, and then crushed after cooling to obtain a lead borosilicate glass solidified substrate.

[0081] The obtained lead borosilicate glass solidification substrate is used to treat simulated high-level radioactive liquid waste. The treatment method is: the granular or powdered glass solidification substrate and the radioactive waste are weighed in an oxide mass ratio of 82:18, a total amount of 100 g is weighed and placed in a 100 mL corundum crucible, and moved to a 1100°C muffle furnace for insulation treatment for 1 hour to obtain a glass melt, the glass melt is poured into a metal mold, and a glass solidification body is obtained after cooling, completing the solidification treatment.

[0082] Example 5

[0083] A lead borosilicate glass solidification substrate comprises the following components based on 100% oxide mass percentage: PbO: 61.2wt%, B2O3: 12.72wt%, SiO2: 15.37wt%, MgO: 5.52wt%, TeO2: 0wt%, Al2O3: 4.65wt%, Li2O: 0.54wt%; 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 the lead borosilicate glass solidified substrate is as follows:

[0085] Taking 100 g of the mixture as a reference, PbO, B2O3, SiO2, MgO, Al2O3, and Li2O are uniformly mixed according to the above mass proportions to obtain a mixture; the mixture is placed in a 100 mL corundum crucible, moved to a 1000°C muffle furnace and melted for 1 hour to obtain a glass melt, the crucible is quickly taken out and the glass melt is poured into a metal mold, and then crushed after cooling to obtain a lead borosilicate glass solidified substrate.

[0086] The obtained lead borosilicate glass solidification substrate is used to treat simulated high-level radioactive liquid waste. The treatment method is: the granular or powdered glass solidification substrate and the radioactive waste are weighed in an oxide mass ratio of 82:18, a total amount of 100 g is weighed and placed in a 100 mL corundum crucible, and moved to a 1100°C muffle furnace for insulation treatment for 1 hour to obtain a glass melt, the glass melt is poured into a metal mold, and a glass solidification body is obtained after cooling, completing the solidification treatment.

[0087] For the rest, please refer to Example 1 and will not be described in detail here.

[0088] Example 6

[0089] A lead borosilicate glass solidified substrate comprises the following components based on 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 the lead borosilicate glass solidified substrate is as follows:

[0091] Taking 100 g of the mixture as a reference, PbO, B2O3, SiO2, MgO and TeO2 are uniformly mixed according to the above mass proportions to obtain a mixture; the mixture is placed in a 100 mL corundum crucible, moved to a 900°C muffle furnace and melted for 1 hour to obtain a glass melt, the crucible is quickly taken out and the glass melt is poured into a metal mold, and then crushed after cooling to obtain a lead borosilicate glass solidified substrate.

[0092] The obtained lead borosilicate glass solidification substrate is used to treat simulated high-level radioactive liquid waste. The treatment method is: the granular or powdered glass solidification substrate and the radioactive waste are weighed in an oxide mass ratio of 84:16, a total amount of 100 g is weighed and placed in a 100 mL corundum crucible, and moved to a 1000°C muffle furnace for heat treatment for 1.5 hours to obtain a glass melt, and the glass melt is poured into a metal mold, and a glass solidified body is obtained after cooling, thereby completing the solidification treatment.

[0093] Example 7

[0094] Different from Example 6, the method for treating simulated high-level radioactive liquid waste is different. The obtained lead borosilicate glass solidified substrate is used to treat the simulated high-level radioactive liquid waste. The treatment method is: the granular or powdered glass solidified substrate and the radioactive waste are weighed in an oxide mass ratio of 76:24, and a total amount of 100 g is weighed and placed in a 100 mL corundum crucible, and moved to an 1100 muffle furnace for heat treatment for 1.5 hours to obtain a glass melt, and the glass melt is poured into a metal mold. After cooling, a glass solidified body is obtained, and the solidification treatment is completed.

[0095] For the rest, please refer to Example 6 and will not be described again here.

[0096] Comparative Example 1

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

[0098] The preparation method of the lead borosilicate glass solidified substrate is as follows:

[0099] Taking 100 g of the mixture as a reference, PbO, B2O3, SiO2 and MgO are uniformly mixed according to the above mass proportions to obtain a mixture; the mixture is placed in a 100 mL corundum crucible, moved to a 1050°C muffle furnace and melted for 1 hour to obtain a glass melt, the crucible is quickly taken out and the glass melt is poured into a metal mold, and then crushed after cooling to obtain a lead borosilicate glass solidified substrate.

[0100] Comparative Example 2

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

[0102] The preparation method of the borosilicate glass solidified substrate is as follows: all the raw materials in the above-mentioned mass proportions are mixed, and after being fully mixed, they are placed in a 100 mL corundum crucible, moved to a 1050° C. muffle furnace and kept warm for 1.5 hours, then the crucible is quickly taken out, and the glass melt is poured into a metal mold, and after cooling, a glass solidified substrate is obtained.

[0103] Comparative Example 3

[0104] A lead borosilicate glass solidified substrate comprises the following components based on 100% oxide mass percentage: 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 the lead borosilicate glass solidified substrate is as follows:

[0106] Taking 100 g of the mixture as the reference, PbO, B2O3 and SiO2 are uniformly mixed according to the above-mentioned mass proportions to obtain a mixture; the mixture is placed in a 100 mL corundum crucible, moved to a 1050°C muffle furnace and melted for 1 hour to obtain a glass melt, the crucible is quickly taken out and the glass melt is poured into a metal mold, and then crushed after cooling to obtain a lead borosilicate glass solidified substrate.

[0107] The obtained lead borosilicate glass solidification substrate is used to treat simulated high-level radioactive liquid waste. The treatment method is: the granular or powdered glass solidification substrate and the radioactive waste are weighed in an oxide mass ratio of 84:16, a total amount of 100 g is weighed and placed in a 100 mL corundum crucible, and moved to a 1150°C muffle furnace for heat treatment for 1.5 hours to obtain a glass melt, the glass melt is poured into a metal mold, and a glass solid body is obtained after cooling, thereby completing the solidification treatment.

[0108] The glass solid bodies obtained in Examples 1 to 7 were subjected to the internationally accepted solid body chemical stability test method: Product Consistency Test (PCT) (ASTM C 1285-02) to evaluate the chemical stability of the glass solid bodies (single element leaching value ≤ 2 g / m 2 ), wherein the elements detected for leaching 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, Si.

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

[0110] Table 1 Chemical stability test results

[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: The total leaching value is the sum of the leaching values ​​of single elements such as Na, Mg, Al, Ca, and Ti.

[0113] From the above Table 1 and Figures 1 to 8 It can be seen that the glass solidified body obtained by the present invention has a typical amorphous bun peak in its XRD diffraction spectrum, which is consistent with the actual object, proving that a homogeneous glass body has been formed. Compared with the actual object in Comparative Example 1, it is found that excessive MgO cannot form a glass body on the glass substrate at a melting temperature of 1050°C; compared with Comparative Example 2, the conventional lead-free borosilicate glass substrate also cannot form a homogeneous glass body at a melting temperature of 1050°C, and needs to be formed at a higher temperature, which can also be supported by its XRD diffraction spectrum.

[0114] It can be seen from the element leaching results of Examples 1 to 7 that the glass solidified substrate and the glass solidified body of the present invention can be processed at a relatively low melting temperature, and for radioactive waste of complex source terms, the inclusion rate can still reach more than 16wt%, and can reach 24wt% under the preferred conditions, and the element leaching amount is low, far less than the specified single element leaching value ≤2g / m 2 It can be seen that the glass solidified body of the present invention has good chemical stability.

[0115] Among them, from the comparison between Examples 3 and 6 and Comparative Example 3, it can be seen that the use of MgO as a network modifier of lead borosilicate glass, compared with the PbO-B2O3-SiO2 ternary basic glass, the addition of MgO is more conducive to improving the waste inclusion rate, and the total element leaching rate is lower. Moreover, when MgO and TeO2 are used together as auxiliary bodies, the melting temperature of the glass solid body can be further reduced, the waste inclusion rate can be improved, and the element leaching can be more effectively inhibited. This is mainly because TeO2 can assist MgO to play an effective role, avoid element leaching to a greater extent, and the waste inclusion rate is higher. However, the inventors have also found through research that when the MgO content is high, the crystallization of the glass substrate cannot be effectively controlled, which will cause the glass substrate to be unable to form a glass body, such as the experimental results of Comparative Example 1. When the MgO content is 0, such as the experimental results of Comparative Example 3 (see Figure 6 ), the actual image of the glass substrate shows glass luster, but when the waste inclusion rate is 16wt%, the actual image of the solidified body shows obvious infusible materials, and the melting effect is poor. Preferably, the addition amount of MgO is controlled between 3.5% and 6%, and the waste inclusion rate and chemical stability of the glass solidified body are better.

[0116] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs can also change and modify the above embodiment. Therefore, the present invention is not limited to the above specific embodiment, and any obvious improvement, replacement or modification made by those skilled in the art on the basis of the present invention belongs to the protection scope of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A lead borosilicate glass solidified substrate, characterized in that: Based on 100% oxide mass percentage, it includes the following components: PbO: 55%~75wt%, B2O3: 9%~16wt%, SiO2: 12%~20wt%, MgO: 1%~7wt%, TeO2: 0~11wt% Al2O3: 0~5wt% Li2O: 0-1wt%; 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 solidified substrate according to claim 1, characterized in that: Calculated by oxide mass percentage 100%, it includes the following components: PbO: 55%~66wt%, B2O3: 12%~16wt%, SiO2: 15%~20wt%, MgO: 3.5~6wt% TeO2: 0~7wt% Al2O3: 0~5wt% Li2O: 0~1wt%.

3. A method for preparing the lead borosilicate glass solidified substrate according to claim 1 or 2, characterized in that: The following steps are involved: PbO, B2O3, SiO2, MgO, TeO2, Al2O3 and Li2O are mixed according to the mass proportion of oxides to obtain a mixture; the mixture is melt-treated at 900°C to 1050°C to obtain a glass melt, and the glass melt is poured into a mold and cooled to obtain a lead borosilicate glass solidified substrate.

4. The method for preparing the lead borosilicate glass solidified 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: The following steps are involved: The granular or powdered glass solidification substrate and the radioactive waste are mixed in an oxide mass ratio of (76-84): (16-24), and the mixture is heat-treated at 1000° C. to 1150° C. to obtain a glass melt, and the glass melt is poured into a mold and cooled to obtain a glass solidification body, thereby completing the solidification treatment of the radioactive waste; Wherein, the glass-solidified substrate is the lead-borosilicate glass-solidified substrate described in any one of claims 1 to 2 or the lead-borosilicate glass-solidified substrate prepared by the preparation method of the lead-borosilicate glass-solidified substrate described in any one of claims 3 to 4.

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

7. The method for treating radioactive waste according to claim 5 or 6, characterized in that: The temperature of the insulation is greater than the melting temperature in the preparation of the glass solidification substrate, and the temperature difference is 100°C to 200°C.

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 glass-solidified substrate to the radioactive waste is (78-82):(18-22).

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