Method for co-glassification of radioactive incineration ashes and contaminated glass fiber filters

Abstract

This invention relates to a method for vitrifying radioactive incineration ash and contaminated fiberglass filter media. The method employs either Method 1 or Method 2, melting and solidifying raw materials containing radioactive incineration ash and contaminated fiberglass filter media to prepare a vitrified body. In Method 1, the raw materials containing radioactive incineration ash and contaminated fiberglass filter media consist of 0wt%-30wt% radioactive incineration ash and 70wt%-100wt% contaminated fiberglass filter media, with a melting temperature of 1100℃-1400℃. In Method 2, the raw materials consist of 0wt%-40wt% radioactive incineration ash, 30wt%-60wt% contaminated fiberglass filter media, and 15wt%-50wt% additives, with a melting temperature of 900℃-1300℃. This invention can effectively and stably obtain a vitrified body that meets disposal requirements, even under conditions of significant fluctuations in the composition of incineration ash and uncertain fly ash composition in the contaminated fiberglass filter media.

Description

Technical Field

[0001] This invention belongs to the field of radioactive nuclear waste treatment technology, specifically relating to a method for co-vitrifying radioactive incineration ash and contaminated fiberglass filter media. Background Technology

[0002] Combustible waste and high-efficiency particulate air (HEPA) filters constitute a large proportion of the low- and intermediate-level radioactive waste generated during the operation of nuclear facilities. Based on the principle of minimizing radioactive waste, incinerating combustible waste and dismantling the filters for cleaning and decontamination is an ideal solution. However, the radioactive incineration ash and contaminated fiberglass filter media produced by these two technologies are unsuitable for direct disposal as final products due to the risks of radioactive element leaching and radioactive aerosol dispersion.

[0003] Currently, the treatment of radioactive incineration ash and contaminated fiberglass filter media is usually carried out separately through cement solidification or supercompression. However, cement solidification is a volume-increasing treatment technology, which increases the amount of waste, and the leaching resistance of the solidified body is lower than that of glass solidification. Supercompression has poor compatibility with these two types of waste. There are also related technologies for glass solidification of radioactive incineration ash and contaminated fiberglass filter media in China, but no engineering applications have been seen. The problems are: 1) Glass solidification of the two solid wastes separately requires the addition of a large amount of glass matrix composition, which increases the cost of glass solidification and increases the weight of the solidified body under the same solid waste conditions; 2) In the existing technology, most research on glass solidification technology for radioactive incineration ash is based on the analysis of a certain type of waste and uses reagents with the same main components to simulate waste for experiments. In actual engineering treatment of waste, the diverse types of radioactive combustible waste, coupled with the random selection and proportioning of materials during incineration, lead to significant fluctuations in the composition and proportion of radioactive incineration ash from different batches. This is particularly true for calcium and aluminum elements, whose large fluctuations can easily cause instability in the vitrified body, resulting in casting difficulties and leaching of radioactive elements, severely impacting the versatility and feasibility of the method. Furthermore, when the vitrification method is only applied to radioactive solid waste with a specific composition, its lack of versatility inevitably leads to unstable properties of the solidified product, which is unacceptable. Although existing technologies typically provide a range of raw materials, practice has shown that not all values ​​within this range can yield a qualified vitrified body; only specific parameter combinations can produce a qualified vitrified body. Therefore, it is necessary to test the composition and content of each batch of incineration ash and develop raw material formulation and vitrification process conditions for different batches of incineration ash. This undoubtedly increases the workload and cost of vitrification of radioactive combustible waste, lacking practical feasibility. 3) Radioactive combustible waste incineration ash often contains nose strips from face masks, metal screws and nuts, and other metal objects. If the filter material is not completely disassembled, aluminum foil may be mixed in. Most existing vitrification technologies cannot handle raw materials containing metal objects, so it is necessary to remove metal objects from the raw materials before vitrification.

[0004] Therefore, it is crucial to develop a method for vitrifying radioactive incineration ash and contaminated fiberglass filter media together, so as to effectively and stably obtain a vitrified body that meets the disposal requirements, under the premise of large fluctuations in the composition of incineration ash and the uncertain composition of fly ash in contaminated fiberglass filter media. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects in the prior art and provide a method for co-vitrifying radioactive solid waste incineration ash and contaminated fiberglass filter media. This method solves a series of defects caused by large fluctuations in the composition and content of different batches of radioactive solid waste when co-vitrifying radioactive solid waste incineration ash and contaminated fiberglass filter media.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for co-vitrifying radioactive incineration ash and contaminated fiberglass filter material, using method one or method two, involves melting and solidifying the raw materials containing radioactive incineration ash and contaminated fiberglass filter material to prepare a vitrified body;

[0008] Method 1: The raw material containing radioactive incineration ash and contaminated glass fiber filter media consists of 0wt% to 30wt% radioactive incineration ash and 70wt% to 100wt% contaminated glass fiber filter media, and the melting temperature is 1100wt% to 1400℃;

[0009] Method 2: The raw materials containing radioactive incineration ash and contaminated fiberglass filter media consist of 0wt%–40wt% radioactive incineration ash, 30wt%–60wt% contaminated fiberglass filter media, and 15wt%–50wt% additives. The melting temperature is 900℃–1300℃. Normally, Method 1 is used, where the contaminated fiberglass filter media and radioactive incineration ash are mixed, melted, and then vitrified. However, when there are strict requirements for the resistance to leaching of radioactive nuclides, Method 2 is required. By adding additives, the melting temperature is lowered, reducing the volatilization of radioactive nuclides. Furthermore, the silica content is increased to ensure the formation of a stable vitrified body under fluctuating raw material composition, thus reducing the resistance to leaching of radioactive nuclides.

[0010] As a further technical solution, in Method 1, when the dust content of the contaminated fiberglass filter material is ≤15wt%, the material compatibility range is: the content of the contaminated fiberglass filter material is ≥70wt%, and the content of radioactive incineration ash is ≤30wt%; when the dust content of the contaminated fiberglass filter material is ≤25wt% and the material compatibility range is: the content of the contaminated fiberglass filter material is ≥80wt%, and the content of radioactive incineration ash is ≤20wt%; when the dust content of the contaminated fiberglass filter material is ≤35wt% and the material compatibility range is: the content of the contaminated fiberglass filter material is ≥90wt%, and the content of radioactive incineration ash is ≤10wt%.

[0011] As a further technical solution, the contaminated fiberglass filter material is obtained by dismantling and separating it from a radioactive waste nuclear-grade air filter;

[0012] As a further technical solution, the radioactive incineration ash is obtained from radioactive combustible waste through incineration or pyrolysis.

[0013] As a further technical solution, the radioactive combustible waste includes one or more of the following: waste resin, masks, cotton clothing, gloves, shoes, protective clothing, anti-fouling plastic sheeting, and rubber gaskets.

[0014] As a further technical solution, the radioactive incineration ash comprises: calcium oxide 20wt%–65wt%; silicon oxide 0wt%–25wt%; aluminum oxide 0wt%–25wt%; iron oxide 0wt%–15wt%; titanium oxide 0wt%–15wt%; sulfur trioxide 0wt%–10wt%; chlorine 0wt%–10wt%; and carbonates 10wt%–40wt% (based on carbon dioxide).

[0015] As a further technical solution, the contaminated fiberglass filter media includes: 30wt%–60wt% silica; 2wt%–15wt% calcium oxide; 0wt%–25wt% carbonate (based on carbon dioxide); 3wt%–15wt% boron oxide; 3wt%–20wt% sodium oxide; 2wt%–15wt% aluminum oxide; 0wt%–10wt% potassium oxide; 0wt%–9wt% barium oxide; and 0wt%–9wt% zinc oxide.

[0016] As a further technical solution, the loss on ignition of the radioactive incineration ash is <5%;

[0017] As a further technical solution, the content of combustible components in the contaminated fiberglass filter material is <15%.

[0018] As a further technical solution, the additives include 25wt% to 60wt% silicon dioxide, 18wt% to 38wt% boron oxide, 5wt% to 13wt% lithium oxide, 7wt% to 15wt% sodium oxide, and 7wt% to 15wt% potassium oxide.

[0019] As a further technical solution, before melting and solidifying the radioactive incineration ash and contaminated fiberglass filter material, it is necessary to remove metal objects from the radioactive incineration ash and contaminated fiberglass filter material, and use a metal detector to ensure that the removal is complete.

[0020] As a further technical solution, the metal object includes one or more of the following: metal block (such as screw), aluminum foil, and metal wire (such as iron wire).

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] This invention ensures that, by limiting the amount of radioactive incineration ash, the dust adhesion of contaminated fiberglass filter media and its composition and dosage / additives, the melting temperature, and the removal of metal objects from radioactive solid waste, it can effectively and stably obtain a vitrified body that meets disposal requirements, even under conditions of significant fluctuations in the composition of incineration ash and uncertain fly ash composition in contaminated fiberglass filter media. This enables the co-processing of radioactive incineration ash obtained from the incineration of combustible radioactive waste and fiberglass filter media obtained from the dismantling of waste filter cartridges. Attached Figure Description

[0023] Figure 1 The infrared characterization image is shown in Example 1.

[0024] Figure 2 The image shown is the XRD characterization diagram of Example 1.

[0025] Figure 3 The infrared characterization image is shown in Example 2;

[0026] Figure 4 The XRD characterization diagram is shown in Example 2.

[0027] Figure 5 This is a photograph of the glass-cured body of Example 5. Detailed Implementation

[0028] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] 1. The main components of the raw materials used in this invention are shown in Table 1. The raw materials used have been free of metal objects.

[0030] Table 1: Main components of various incineration ash and contaminated fiberglass filter media (unit: wt%)

[0031]

[0032] The dust content of both filter media A and filter media B is ≤15wt%.

[0033] The loss on ignition of incineration ash A, incineration ash B, and incineration ash C is <5%;

[0034] The combustible component content of filter media A and filter media B is <15%.

[0035] 2. Unless otherwise specified, the raw materials used in this invention are commercially available reagents.

[0036] The present invention will now be described in further detail with reference to the accompanying drawings.

[0037] Example 1

[0038] Then, take 3g of incinerator ash A and 7g of filter material A, and place them in a 100ml crucible. Place the crucible in a muffle furnace, heat to 200℃ for 20 minutes, hold for 20 minutes, then heat to 1100℃ for another 100 minutes, and then hold at the specified temperature for 4 hours to complete melting. Then cool with the furnace, reaching room temperature in approximately 24 hours. XRD and infrared characterization both indicate that the solidified body is a homogeneous glassy state (see...). Figures 1-2 ).

[0039] Example 2

[0040] Then, take 3g of incinerator ash A and 7g of filter material B, and place them in a 100ml crucible. Place the crucible in a muffle furnace, heat to 200℃ for 20 minutes, hold for 20 minutes, then heat to 1200℃ for another 100 minutes, and hold at the specified temperature for 4 hours to complete melting. Then cool with the furnace, reaching room temperature in approximately 24 hours. XRD and infrared characterization both indicate that the solidified body is a homogeneous glassy state (see...). Figures 3-4 ).

[0041] Example 3

[0042] Take 2g of incinerator ash B, 4g of filter material A, and 4g of additives (including: 1.5g silicon dioxide, 1.25g boron oxide, 0.25g lithium oxide, 0.5g sodium oxide, and 0.5g potassium oxide), and place them in a 100ml crucible. Place the crucible in a muffle furnace, heat to 200℃ for 20 minutes, hold for 20 minutes, then heat to 1000℃ for another 100 minutes, and then hold at the specified temperature for 4 hours to complete melting. Then cool with the furnace, allowing it to reach room temperature in approximately 24 hours.

[0043] Example 4

[0044] Take 2g of incinerator ash (C), 4g of filter material (A), and 4g of additives (including: 1g of silicon dioxide, 1.5g of boron oxide, 0.5g of lithium oxide, 0.5g of sodium oxide, and 0.5g of potassium oxide), and place them in a 100ml crucible. Place the crucible in a muffle furnace, heat to 200℃ for 20 minutes, hold for 20 minutes, then heat to 1000℃ for another 100 minutes, and then hold at the specified temperature for 4 hours to complete melting. Then cool with the furnace, allowing it to reach room temperature in approximately 24 hours.

[0045] Example 5

[0046] According to the composition ratio of Example 1, 15g of incineration ash A and 35g of filter material A were taken, and 0.5g of cesium chloride was added as a simulated radioactive nuclide, and placed in a 200ml crucible. The crucible was placed in a muffle furnace, heated to 200°C for 20 minutes, held for 20 minutes, and then heated to 1200°C for 100 minutes. The temperature was held at this temperature for 4 hours, and then poured into a preheated graphite oil bath, with 3 pieces of each type poured. Subsequently, the mixture was annealed at 500°C to obtain a glass-cured body (see Example 1). Figure 5 The leaching test of the solidified body was conducted using the method specified in GB / T 7023-2011. The experimental results showed that the cumulative leaching rate did not exceed 4.13 × 10⁻⁶ days. -5 cm / d.

[0047] Comparative Example 1

[0048] Take 4g of incinerator ash (C) and 6g of filter material (B), and place them in a 100ml crucible. Place the crucible in a muffle furnace, heat to 200℃ for 20 minutes, hold for 20 minutes, then heat to 1200℃ for another 100 minutes, and hold at the specified temperature for 4 hours to complete melting. Then cool with the furnace, reaching room temperature in approximately 24 hours. The solidified body contains a large amount of white unmelted material and cannot form a homogeneous glassy solid.

[0049] Comparative Example 2:

[0050] Take 4g of incinerator ash (B) and 6g of filter material (B), and place them in a 100ml crucible. Place the crucible in a muffle furnace, heat to 200℃ for 20 minutes, hold for 20 minutes, then heat to 1200℃ for another 100 minutes, and hold at the specified temperature for 4 hours to complete melting. Then cool with the furnace, reaching room temperature in approximately 24 hours. The solidified body exhibits numerous scaly stones and severe crystallization.

[0051] Comparative Example 3

[0052] Take 9g of filter material A and 1g of aluminum foil (obtained from dismantling a high-efficiency filter cartridge) and place them in a 100ml crucible. Place the crucible in a muffle furnace, heat to 200℃ for 20 minutes, hold for 20 minutes, then heat to 1200℃ for 100 minutes, and then hold at the specified temperature for 4 hours to complete melting. Then cool with the furnace, reaching room temperature in approximately 24 hours. A white foamy substance appears on the surface of the solidified body, which is the oxidation of metallic aluminum to aluminum oxide, preventing the formation of a homogeneous glassy solidified body.

[0053] Comparative Example 4

[0054] Take 7g of incinerator ash (B) and 3g of filter material (A), and place them in a 100ml crucible. Place the crucible in a muffle furnace, heat to 200℃ for 20 minutes, hold for 20 minutes, then heat to 1200℃ for another 100 minutes, and then hold at the specified temperature for 4 hours to complete melting. Then cool with the furnace, reaching room temperature in approximately 24 hours. The solidified body was a heterogeneous substance, and a glass-cured body could not be obtained.

[0055] Comparative Example 5

[0056] Take 8g of incinerator ash (B) and 2g of filter material (A), and place them in a 100ml crucible. Place the crucible in a muffle furnace, heat to 200℃ for 20 minutes, hold for 20 minutes, then heat to 1200℃ for another 100 minutes, and hold at the specified temperature for 4 hours to complete melting. Then cool with the furnace, reaching room temperature in approximately 24 hours. The solidified body was a heterogeneous substance, and a glass-cured body was not obtained.

[0057] Comparative Example 6

[0058] Take 9g of incinerator ash B and 1g of filter material A, and place them in a 100ml crucible. Place the crucible in a muffle furnace, heat to 200℃ for 20 minutes, hold for 20 minutes, then heat to 1200℃ for another 100 minutes, and then hold at the specified temperature for 4 hours to complete melting. Then cool with the furnace, reaching room temperature in approximately 24 hours. The solidified body is a heterogeneous substance, and a glass-cured body could not be obtained.

[0059] The embodiments described above are merely preferred embodiments of the present invention, and not an exhaustive list of all possible implementations of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A method for co-vitrifying radioactive incineration ash and contaminated fiberglass filter material, characterized in that, The raw materials containing radioactive incineration ash and contaminated fiberglass filter media are melted and solidified to prepare a glass-cured body; wherein, The raw material containing radioactive incineration ash and contaminated glass fiber filter media consists of 0wt%~30wt% radioactive incineration ash and 70wt%~100wt% contaminated glass fiber filter media, and the melting temperature is 1100℃~1400℃. When the dust content of the contaminated fiberglass filter media is ≤15wt%, the material blending range is: contaminated fiberglass filter media content ≥70wt%, radioactive incineration ash content ≤30wt%; when the dust content of the contaminated fiberglass filter media is 15wt% ≤25wt%, the material blending range is: contaminated fiberglass filter media content ≥80wt%, radioactive incineration ash content ≤20wt%; when the dust content of the contaminated fiberglass filter media is 25wt% ≤35wt%, the material blending range is: contaminated fiberglass filter media content ≥90wt%, radioactive incineration ash content ≤10wt%. Before melting and solidifying the radioactive incineration ash and contaminated fiberglass filter material, it is necessary to remove any metal objects from the radioactive incineration ash and contaminated fiberglass filter material, and to use a metal detector to ensure that the removal is complete. The metal object includes one or more of the following: metal block, aluminum foil, and metal wire.

2. The method for co-vitrifying radioactive incineration ash and contaminated fiberglass filter material according to claim 1, characterized in that, The contaminated fiberglass filter material is obtained by dismantling and separating it from a radioactive waste nuclear-grade air filter; the radioactive incineration ash is obtained by incinerating or pyrolyzing radioactive combustible waste.

3. The method for co-vitrifying radioactive incineration ash and contaminated fiberglass filter material according to claim 2, characterized in that, The radioactive combustible waste includes one or more of the following: waste resin, masks, cotton clothing, gloves, shoes, protective clothing, anti-fouling plastic sheeting, and rubber gaskets.

4. The method for co-vitrifying radioactive incineration ash and contaminated fiberglass filter material according to claim 1, characterized in that, The radioactive incineration ash comprises: calcium oxide 20wt%~65wt%; silicon oxide 0wt%~25wt%; aluminum oxide 0wt%~25wt%; iron oxide 0wt%~15wt%; titanium oxide 0wt%~15wt%; sulfur trioxide 0wt%~10wt%; chlorine 0wt%~10wt%; and carbonates 10wt%~40wt% (based on carbon dioxide).

5. The method for co-vitrifying radioactive incineration ash and contaminated fiberglass filter material according to claim 1, characterized in that, The contaminated fiberglass filter media includes: silicon dioxide 30wt%~60wt%; calcium oxide 2wt%~15wt%; carbonates (based on carbon dioxide) 0wt%~25wt%; boron oxide 3wt%~15wt%; sodium oxide 3wt%~20wt%; aluminum oxide 2wt%~15wt%; potassium oxide 0wt%~10wt%; barium oxide 0wt%~9wt%; and zinc oxide 0wt%~9wt%.

6. The method for co-vitrifying radioactive incineration ash and contaminated fiberglass filter material according to claim 1, characterized in that, The loss on ignition of the radioactive incineration ash is less than 5%, and the content of combustible components in the contaminated fiberglass filter material is less than 15%.

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