CN114388166A

CN114388166A - Method for curing chlorine and/or fluorine-containing radioactive wastes by using glass ceramics and glass ceramic cured body obtained by using method

Info

Publication number: CN114388166A
Application number: CN202111660439.3A
Authority: CN
Inventors: 刘学阳; 乔延波; 钱正华; 张强; 段熙雷; 李霖
Original assignee: Shanghai Institute of Applied Physics of CAS
Current assignee: Shanghai Institute of Applied Physics of CAS
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2022-04-22

Abstract

The invention relates to a method for curing radioactive waste containing chlorine and/or fluorine by means of glass-ceramics, comprising: according to the chlorine and/or fluorine in the radioactive waste and Ca₃(PO₄)₂In the proportion of P, adding radioactive waste, P_(mol):F(Cl)_(mol)Mixing 3-5 parts, drying and exhausting, and grinding the obtained material into powder; introducing the powder into a graphite mold; placing the graphite mold in a sintering furnace; vacuumizing the sintering furnace, setting the pressurizing pressure to be 0.3t-1.5t, setting the heating program to be 50-100 ℃/min, heating to 350-550 ℃, and performing discharge plasma sintering for 1-3 mins; the glass ceramic solidified body was taken out from the graphite mold using a mold stripper. The invention also provides a glass ceramic solidified body obtained by the method. According to the method, the material is converted into a solidified body form by a one-step method, the preparation process is simplified, the process is simple, and the time is short.

Description

Method for curing chlorine and/or fluorine-containing radioactive wastes by using glass ceramics and glass ceramic cured body obtained by using method

Technical Field

The invention relates to the field of radioactive waste solidification treatment and environmental protection, in particular to a method for solidifying chlorine and/or fluorine-containing radioactive waste through glass ceramic and a glass ceramic solidified body obtained by the method.

Background

The dry post-processing is a spent fuel post-processing technology suitable for an advanced nuclear fuel circulation technology and is one of key technologies for the sustainable development of nuclear energy. The main high-level waste is halogen-containing compound solid waste salt generated in the electrolytic reduction and electrolytic refining processes, and is called fused salt waste for short. The fused salt waste is a solid salt of halogen (Cl, F) containing compounds, carries small amount of actinide and unseparated Fission Products (FP), has the characteristics of strong radioactivity, corrosiveness, poor chemical stability, deliquescence, low melting point and the like, can cause the waste salt to generate halogen-containing gas through radiolysis due to the high radioactivity, can contain toxic components (such as beryllium fluoride), is a complex system with strong radioactivity-chemical corrosiveness-chemical toxicity, and is difficult to treat and dispose. Therefore, the research on the high radioactive molten salt waste treatment technology generated by the spent fuel dry post-treatment has important significance on the development of spent fuel post-treatment and nuclear fuel circulation technology. Extensive research has been conducted internationally on the treatment of molten salt waste, with researchers in countries such as the united states, france, australia, etc. conducting research on the solidification treatment of halogen-containing waste high-level waste and dry post-treated molten salt waste. Compared with the traditional glass solidification, the Waste needs to be melted, the process is complicated, and the release of Molten Fluoride and volatile nuclides and the problem of tail gas treatment need to be considered (Molten Salt paper of the Committee on retrieval of distributed and Tank Water NRC, Evaluation of the U.S. Deparatment of Energy's Alternatives for the Removal and distribution of Molten Salt Reactor express Fluoride Salt technical Report 1997; Siemer D.D.Improving the integral fast Reactor's disposed Salt technical system technical Report 1997, 2011,178:341 area 352; Siemer D.D.Sal Reactor reagent Water Reactor technical Report No. 32; 2012,185. monitoring Reactor vessel S.32. monitoring Reactor S.32. and monitoring Reactor S.32. monitoring Reactor S. 2. monitoring Reactor S.32. monitoring Reactordes(PbCl₂,CdCl₂)and alkaline chlorides(NaCl,KCl)into phosphate glasses.Chemistry of materials,2000,12(7):1921-1925；Lavrinovich Y.G.,Kormilitsyn M.,Konovalov V.,et al.Vitrification of chloride wastes in the pyroelectrochemical method of reprocessing irradiated nuclear fuel.At.Energ,2003,95(5):781-785；Mesko M.,Day D.,Bunker B.Immobilization of CsCl and SrF₂ in iron phosphate glass.Waste Manage.,2000,20(4):271-278；Yaping Sun,Xiaobin Xia,Yanbo Qiao,et al.Properties of Phosphate-glass Waste forms Containing Fluorides from Molten Salt Reactor.Nuclear Science and Techniques,2016,27(3):96-102；Yaping Sun,Xiaobin Xia,Yanbo Qiao,et al.Immobilization of Simulated Radioactive Fluoride Waste in Phosphate Glass.Science China Materials,2016,59(4):279-286；Xueyang Liu,Yanbo Qiao,Zhenghua Qian,et al.Research on chemical durability of iron phosphate glass wasteforms vitrifying SrF₂ and CeF₃Journal of Nuclear Materials 508(2018) 286-.

There are reports in the literature (Riley, B.J., McFarlane, J., DelCul, G.D., et al. Molten salt minor water and effect management sequences: A review. Nucl. Eng. Des.2019,345, 94-109; Metalfe B, Donald I. Candate water forms for the immobilization of chloride-containing radioactive water. journal of non-crystalline solids 2004,348: 225-. At present, glass ceramic solidification technologies developed based on the target crystals comprise a glass ceramic solid phase sintering technology based on a two-step method, a hot isostatic pressing glass ceramic preparation technology and the like, and due to the defects of complex process flow, high requirements on process conditions, long preparation time and the like, the glass ceramic solidification technologies are not applied and popularized in engineering.

Disclosure of Invention

In order to solve the problems of complex process flow and the like of the glass ceramic curing technology in the prior art, the invention provides a method for curing chlorine and/or fluorine-containing radioactive wastes through glass ceramics and a glass ceramic cured body obtained by the method.

The invention provides a method for curing chlorine and/or fluorine-containing radioactive waste by means of glass-ceramics, comprising: s1, mixing Fe₂O₃、(NH₄)H₂PO₄And H₃BO₃Grinding and mixing to obtain raw material, adding Ca to the raw material₃(PO₄)₂After grinding and mixing, Ca is added according to chlorine and/or fluorine in the radioactive waste₃(PO₄)₂In the proportion of P, adding radioactive waste, P_(mol):F(Cl)_(mol)Mixing 3-5 parts, drying and exhausting, and grinding the obtained material into powder; s2, introducing the powder into a graphite die; s3, placing the graphite mold in a sintering furnace; s4, vacuumizing the Sintering furnace, setting the pressurizing pressure to be 0.3t-1.5t, setting the heating program to be 50-100 ℃/min, heating to 350-; s5, the glass ceramic solidified body is taken out of the graphite mold by using a mold stripper.

Preferably, the radioactive waste is a fluoride and/or chloride containing radioactive waste. More preferably, the radioactive waste is a medium high radioactive waste containing fluoride and/or chloride, wherein the medium radioactive waste has a radioactivity level of greater than 4 x 10⁹Bq/kg, high level radioactive activity of waste greater than 4X 10¹¹Bq/kg. In a preferred embodiment, the radioactive waste is fluoride-containing radioactive waste. In a preferred embodiment, the mole percentage of each component in the radioactive waste is 63LiF-28MgF₂-1.2CsF-1.6SrF₂-1.2CeF₃-4.96ZrF₄-0.04AnFn, An being An actinide and n being 2 or 3 or 4 or 5 or 6 or 7. In a preferred embodiment, the radioactive waste is chloride-containing radioactive waste. In a preferred embodiment, the molar percentage of each component in the radioactive waste is 63LiCl-28MgCl₂-1.2CsCl-1.6SrCl₂-1.2CeCl₃-4.96ZrCl₄-0.04AnCln, An being An actinide and n being 2 or 3 or 4 or 5 or 6 or 7.

Preferably, in step S1, Fe₂O₃、(NH₄)H₂PO₄And H₃BO₃The proportion of the components is 36-40 wt% to 54-60 wt% to 0-10 wt%. In a preferred embodiment, Fe₂O₃、(NH₄)H₂PO₄And H₃BO₃The proportion of (A) is 38 wt% -57 wt% -5 wt%.

Preferably, in step S1, the raw material is mixed with Ca₃(PO₄)₂The mass ratio of (A) to (B) is 1: 2. In a preferred embodiment, the feedstock is mixed with Ca₃(PO₄)₂The mass ratio of (A) to (B) is 1: 1.5.

Preferably, step S2 includes: the inner wall of the cylinder of the graphite mold is tightly attached to the first graphite paper, the second graphite paper is paved at the bottom of the cylinder, powder is guided into a space limited by the first graphite paper and the second graphite paper, the third graphite paper is covered above the powder, and the end enclosure of the graphite mold is inserted into the cylinder above the third graphite paper and pressed downwards.

Preferably, in step S4, a negative pressure of 1000Pa is maintained after evacuation.

Preferably, in step S4, the pressurization pressure is set to 0.5t to 1.2 t. In a preferred embodiment, the pressurization pressure is set to 0.8 t.

Preferably, in step S4, the heating program is set to 50 ℃/min to 350 ℃, 100 ℃/min to 450-.

Preferably, in step S4, after spark plasma sintering, the temperature is reduced to below 50 ℃ at a rate of 50 ℃/min, the heating process is turned off, and the vacuum pump is turned off.

The invention also provides a glass ceramic solidified body obtained by the method.

Preferably, the glass-ceramic cured body comprises a ceramic mixture bonded by iron phosphate glass, the ceramic mixture being a mixture of fluoro (chloro) apatite, fluoro (chloro) apatite and monazite.

Preferably, the chemical structural formulas of the fluoro (chloro) apatite, the fluoro (chloro) apatite and the monazite are respectively M₅(PO₄)₃F，M₅(PO₄)₃Cl and NPO₄Wherein M is metal cation of Li, Ca, Ba, Sr, Cs, La, U and Zr, and N is cation of Ce, Th, U and Pu. In a preferred embodiment, M is Ca, Sr, Mg and N is Ce.

According to the method for curing the radioactive wastes containing chlorine and/or fluorine by the glass ceramic, all materials are mixed, and the materials are converted into a solidified body form by a one-step method by utilizing the heating characteristic of the discharge plasma, so that the preparation process is simplified, the process is simple, the time is short, and the one-step synthesis is carried out. The invention uses solid powder (Fe)₂O₃、(NH₄)H₂PO₄、H₃BO₃And Ca₃(PO₄)₂) The raw material can be directly mixed with fluoride and/or chloride to prepare a solidified body, so that the reaction and corrosion risks of the fluoride and/or chloride are reduced; because no liquid exists, the evaporation amount in the preparation process and the generation of secondary radioactive waste liquid are reduced. The invention can quickly convert the powder into a firm glass ceramic solidified body (1-3 mins) at a lower temperature (350-550 ℃), effectively reduces the volatilization of volatile elements such as fluorine, chlorine, cesium and the like, and reduces the flow of tail gas treatment at the rear end and the generation of secondary waste. The solidified body prepared by the invention has more uniform crystal particles and smaller granularity, so that the solidified body reaches 98.5-99.8% of theoretical density and has higher strength. The generated solidified body consists of target crystals and glass together, has good water erosion resistance and shows good chemical stability.

Drawings

FIG. 1 is a schematic diagram of the construction of an SPS graphite mold in accordance with a preferred embodiment of the invention;

FIG. 2 shows first and third graphite papers of the SPS graphite mold of FIG. 1;

FIG. 3 shows a second graphite paper of the SPS graphite mold of FIG. 1;

FIG. 4 is a schematic diagram of the structure of an SPS sintering furnace according to a preferred embodiment of the invention;

FIG. 5 is an SEM photograph of a glass-ceramic solidified body obtained in example 5 according to the present invention;

FIG. 6 is an SEM photograph of a glass-ceramic solidified body obtained according to comparative example 1 of the present invention.

Detailed Description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The raw materials in the following examples are all commercially available products.

The particle size of the fluoride molten salt waste in the following examples is less than or equal to 1 mm.

Glass raw materials and Ca in the following examples₃(PO₄)₂The purity is more than or equal to 99 wt%, and the granularity is less than or equal to 0.35 um.

The radioactive waste in the examples described below is a medium to high radioactive waste containing fluoride and/or chloride. For example, the radioactive waste is radioactive waste a containing fluoride. In a preferred embodiment, the mole percentage of each component in the radioactive waste is 63LiF-28MgF₂-1.2CsF-1.6SrF₂-1.2CeF₃-4.96ZrF₄-0.04AnFn, An being An actinide and n being 2 or 3 or 4 or 5 or 6 or 7. As another example, the radioactive waste is a chloride-containing radioactive waste B. In a preferred embodiment, the molar percentage of each component in the radioactive waste is 63LiCl-28MgCl₂-1.2CsCl-1.6SrCl₂-1.2CeCl₃-4.96ZrCl₄-0.04AnCln, An being An actinide and n being 2 or 3 or 4 or 5 or 6 or 7.

An SPS graphite mold used in the following embodiments is shown in fig. 1, and includes a cylinder 1, a first graphite paper 2, a second graphite paper 3, a third graphite paper 4, and a sealing head 5, wherein the cylinder 1 is opened upward, the first graphite paper 2 is tightly attached to an inner sidewall of the cylinder 1, the second graphite paper 3 is laid on a bottom wall of the cylinder 1, a material 6 is placed in a space defined by the first graphite paper 2 and the second graphite paper 3, the third graphite paper 4 is laid on a top of the material 6, and the sealing head 5 is inserted into the cylinder 1 above the third graphite paper 4 to seal the material 6. Preferably, the cylinder 1 is cylindrical, the first graphite paper 2 is formed by folding a square graphite paper as shown in fig. 2, and the second graphite paper 3 and the third graphite paper 4 are circular as shown in fig. 3.

An SPS sintering furnace used in the following embodiment is shown in fig. 4, and includes the above-described mold, a ram 7, a temperature detector 8, and a heating element 9, wherein the ram 7 is arranged to act on the head 5 of the mold to pressurize the mold, the temperature detector 8 is arranged in the mold to detect the temperature of the mold, and the heating element 9 is arranged at both ends of the mold to heat the mold. Specifically, pulse current is directly introduced between powder particles of the material 6 in the die for heating and sintering, and in the SPS sintering process, discharge plasma is instantly generated when the electrode is introduced with the direct current pulse current, so that each particle in the sintered body uniformly generates Joule heat per se and activates the particle surface.

Example 1

Mixing Fe₂O₃、(NH₄)H₂PO₄And H₃BO₃Grinding and mixing the raw materials according to the proportion of 36-54-10 wt% to prepare raw materials, and adding Ca into the raw materials according to the mass ratio of 1:1₃(PO₄)₂After grinding and mixing, according to the fluorine, chlorine and Ca in the simulated waste₃(PO₄)₂Adding radioactive waste into raw material at a ratio of P_(mol):F(Cl)_(mol)Uniformly mixing the components, drying and exhausting gas at 400 ℃, grinding the obtained materials into powder, wherein the particle size of the powder is less than or equal to 0.35 um.

Taking out a clean SPS graphite die, cutting a piece of square graphite paper and two pieces of circular graphite paper with the same inner diameter as the die according to the size of the die, firstly rolling the square graphite paper into a cylindrical shape, then placing the cylindrical graphite paper into a barrel 1 to enable the square graphite paper to be tightly attached to the inner wall to provide first graphite paper 2, then placing a piece of circular graphite paper at the bottom of the barrel 1 to enable the circular graphite paper to be flatly laid to provide second graphite paper 3, introducing powder into a space defined by the first graphite paper 2 and the second graphite paper 3, adding the powder to 95% of the volume of the barrel 1, then covering a layer of circular graphite paper above the powder to provide third graphite paper 4, and then inserting an end enclosure 5 into the barrel 1 until the position cannot be pressed downwards continuously by hands.

The mold filled with the materials is placed in an SPS sintering furnace, after the mold is placed stably, the pressure head 7 is lowered manually until a pressure gauge starts to display a pressure value, the mold stops lowering, the temperature detector 8 is inserted into a monitoring hole in the middle of the mold, the mold is placed again, the upper pressure head and the lower pressure head of the mold are guaranteed to be on the same vertical line with the mold, and the furnace door is closed after the mold is adjusted.

After the furnace door was closed, the vacuum pump was opened to discharge the gas in the furnace and the negative pressure of 1000Pa was maintained. Setting the pressurizing pressure to be 0.3t, starting the heating element 9, setting the heating program to heat to 350 ℃ at 50 ℃/min, maintaining the temperature for heating for 3mins, then cooling to below 50 ℃ at 50 ℃/min, closing the heating program, closing the vacuum pump, and relieving the negative pressure.

And opening the furnace door, slowly lifting the pressure head 7, taking out the mold, removing the seal head 5, taking out the internal solidified body by using a demolding machine, and removing graphite paper to obtain the final glass ceramic solidified body.

Example 2

Component A of this example simulates fluorine and Ca in waste₃(PO₄)₂Proportion P of P in the starting Material_(mol):F_(mol)The rest is the same as example 1.

Example 3

Component B of this example simulates chlorine and Ca in waste₃(PO₄)₂Proportion P of P in the raw materials_(mol):Cl_(mol)The rest is the same as example 1.

Example 4

Example 5

Mixing Fe₂O₃、(NH₄)H₂PO₄And H₃BO₃Grinding and mixing the raw materials according to the proportion of 36-54-10 wt% to prepare raw materials, and adding Ca into the raw materials according to the mass ratio of 1:1₃(PO₄)₂After grinding and mixing, the simulation of fluorine and Ca in the waste according to component A₃(PO₄)₂Raw materialsAdding radioactive waste in the proportion of P_(mol):F_(mol)Uniformly mixing the components, drying and exhausting gas at 400 ℃, grinding the obtained materials into powder, wherein the particle size of the powder is less than or equal to 0.35 um.

After the furnace door was closed, the vacuum pump was opened to discharge the gas in the furnace and the negative pressure of 1000Pa was maintained. Setting the pressurizing pressure to be 0.5t, starting the heating element 9, setting the heating program to heat to 350 ℃ at 50 ℃/min, heating to 450 ℃ at 100 ℃/min, maintaining the temperature for heating for 3mins, then cooling to below 50 ℃ at 50 ℃/min, closing the heating program, closing the vacuum pump, and relieving the negative pressure.

Opening the furnace door, slowly lifting the pressure head 7, taking out the mold, removing the end enclosure 5, taking out the internal solidified body by using a demolding machine, removing graphite paper, and obtaining a final glass ceramic solidified body, wherein an SEM image of the glass ceramic solidified body is shown in figure 5, and the sample can be observed through the surface morphology of the sample, is relatively compact in whole and uniform in particles, shows that the components react with each other and are uniformly mixed with each other, and is supposed to have relatively good stability.

Example 6

Mixing Fe₂O₃、(NH₄)H₂PO₄And H₃BO₃Grinding and mixing the raw materials according to the proportion of 38-57-5 wt% to prepare a raw material, and adding Ca into the raw material according to the mass ratio of 1:1.5₃(PO₄)₂After grinding and mixing, according to the fluorine, chlorine and Ca in the simulated waste₃(PO₄)₂Adding radioactive waste into raw material at a ratio of P_(mol):F(Cl)_(mol)Uniformly mixing the components, drying and exhausting gas at 400 ℃, grinding the obtained materials into powder, wherein the particle size of the powder is less than or equal to 0.35 um.

Example 7

The pressurizing pressure in this example was set to 0.8t, and the rest was the same as in example 6.

Example 8

The pressure was set to 1.2t in this example, and the rest was the same as in example 6.

Example 9

The pressure was set to 1.5t in this example, and the rest was the same as in example 6.

Example 10

Mixing Fe₂O₃、(NH₄)H₂PO₄And H₃BO₃Grinding and mixing the raw materials according to the proportion of 40-60-0 wt% to prepare raw materials, and adding Ca into the raw materials according to the mass ratio of 1:2₃(PO₄)₂After grinding and mixing, according to the fluorine, chlorine and Ca in the simulated waste₃(PO₄)₂Adding radioactive waste into raw material at a ratio of P_(mol):F(Cl)_(mol)Uniformly mixing the components, drying and exhausting gas at 400 ℃, grinding the obtained materials into powder, wherein the particle size of the powder is less than or equal to 0.35 um.

After the furnace door was closed, the vacuum pump was opened to discharge the gas in the furnace and the negative pressure of 1000Pa was maintained. Setting the pressurizing pressure to be 0.3t, starting the heating element 9, setting the heating program to heat to 350 ℃ at 50 ℃/min, heating to 550 ℃ at 100 ℃/min, maintaining the temperature for heating for 3mins, then cooling to below 50 ℃ at 50 ℃/min, closing the heating program, closing the vacuum pump, and relieving the negative pressure.

Example 11

After the furnace door was closed, the vacuum pump was opened to discharge the gas in the furnace and the negative pressure of 1000Pa was maintained. Setting the pressurizing pressure to be 0.3t, starting the heating element 9, setting the heating program to heat to 350 ℃ at 50 ℃/min, heating to 450 ℃ at 100 ℃/min, maintaining the temperature for heating for 2mins, then cooling to below 50 ℃ at 50 ℃/min, closing the heating program, closing the vacuum pump, and relieving the negative pressure.

Example 12

The temperature holding time at the highest temperature in this example was 1min, as in example 11.

Comparative example 1

Mixing Fe₂O₃、(NH₄)H₂PO₄And H₃BO₃Grinding and mixing the raw materials according to the proportion of 36-54-10 wt% to prepare raw materials, and adding Ca into the raw materials according to the mass ratio of 1:1₃(PO₄)₂After grinding and mixing, the simulation of fluorine and Ca in the waste according to component A₃(PO₄)₂Adding radioactive waste into raw material at a ratio of P_(mol):F_(mol)Uniformly mixing the components, drying and exhausting gas at 400 ℃, grinding the obtained materials into powder, wherein the particle size of the powder is less than or equal to 0.35 um.

Taking out the clean 316 stainless steel die, cutting out a piece of square reagent paper and two pieces of round reagent paper with the same inner diameter as the die according to the size of the die, firstly rolling the square reagent paper into a cylinder shape, then placing the cylinder body into the square reagent paper to be tightly attached to the inner wall, then placing a piece of round reagent paper at the bottom of the cylinder body to be flatly paved, introducing the powder, adding the powder to 95% of the volume of the cylinder body, then covering a layer of round reagent paper above the powder, and then inserting the end socket into the cylinder body until the end socket can not be pressed down continuously by hand.

Placing the mold filled with the material on a press machine, after the mold is placed stably, manually descending a pressure head until a pressure gauge starts to display a pressure value, stopping descending, placing the mold again, ensuring that an upper pressure head and a lower pressure head of the mold are integrally on a vertical line, starting an automatic pressure application program after the mold is adjusted, setting a termination pressure to be 40MPa, maintaining the pressure for 1min, releasing the pressure, withdrawing the mold, and releasing a pressed sample from the mold.

And (4) removing the reagent paper on the surface of the pressed sample, and then putting the sample into a drying oven to dry for 24 h. And then placing the glass ceramic solidified body in a resistance heating furnace for heating, setting a heating program to heat to 450 ℃ at a speed of 10 ℃/min, preserving heat for 1h at 450 ℃, then heating to 850 ℃ at a speed of 10 ℃/min, maintaining the temperature for heating for 3h, then closing the heating program until the temperature in the furnace is reduced to below 60 ℃, taking out the sample, and obtaining a final glass ceramic solidified body sample, wherein an SEM (scanning electron microscope) picture of the glass ceramic solidified body sample is shown in figure 6, and the surface of the solidified body sample is obviously provided with obvious concave parts and convex parts, crystals in the whole plane are not uniform, good morphological characteristics cannot be shown, and the performance of the solidified body is influenced.

The solidified body prepared in the comparative example can obtain the target crystal, but due to different heating modes and no pressure applied during heating, the surface of the formed solidified body has very tiny air holes and is not dense enough, which is not favorable for the solidification of the fluoride salt waste.

Comparative example 2

After the furnace door was closed, the vacuum pump was opened to discharge the gas in the furnace and the negative pressure of 1000Pa was maintained. Setting the pressurizing pressure to be 0.3t, starting the heating element 9, setting the heating program to heat to 350 ℃ at 50 ℃/min, heating to 850 ℃ at 100 ℃/min, maintaining the temperature for heating for 3mins, then cooling to below 50 ℃ at 50 ℃/min, closing the heating program, closing the vacuum pump, and relieving the negative pressure.

And opening the furnace door, slowly lifting the pressure head 7, taking out the mold, removing the end enclosure 5, and taking out the internal solidified body by using a demolding machine, wherein the added materials are completely melted at 850 ℃ so that the final glass ceramic solidified body cannot be obtained.

Component A simulation waste in comparative example 1, a solidified body was obtained by cold-press sintering at 850 ℃ for 3 hours, but in comparative example 2, the added material was melted and could not be formed under pressure under the same conditions. In example 5, the same composition was molded by holding at 450 ℃ for 3 mins.

The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.

Claims

1. A method for curing chlorine and/or fluorine containing radioactive waste through glass-ceramics, the method comprising:

s1, mixing Fe₂O₃、(NH₄)H₂PO₄And H₃BO₃Grinding and mixing to obtain raw material, adding Ca to the raw material₃(PO₄)₂After grinding and mixing, Ca is added according to chlorine and/or fluorine in the radioactive waste₃(PO₄)₂In the proportion of P, adding radioactive waste, P_(mol):F(Cl)_(mol)Mixing 3-5 parts, drying and exhausting, and grinding the obtained material into powder;

s2, introducing the powder into a graphite die;

s3, placing the graphite mold in a sintering furnace;

s4, vacuumizing the sintering furnace, setting the pressurizing pressure to be 0.3t-1.5t, setting the heating program to be 50-100 ℃/min, heating to 350-;

s5, the glass ceramic solidified body is taken out of the graphite mold by using a mold stripper.

2. The method of claim 1, wherein in step S1, Fe₂O₃、(NH₄)H₂PO₄And H₃BO₃The proportion of the components is 36-40 wt% to 54-60 wt% to 0-10 wt%.

3. The method of claim 1, wherein in step S1, the raw material is mixed with Ca₃(PO₄)₂The mass ratio of (A) to (B) is 1: 2.

4. The method according to claim 1, wherein step S2 includes: the inner wall of the cylinder of the graphite mold is tightly attached to the first graphite paper, the second graphite paper is paved at the bottom of the cylinder, powder is guided into a space limited by the first graphite paper and the second graphite paper, the third graphite paper is covered above the powder, and the end enclosure of the graphite mold is inserted into the cylinder above the third graphite paper and pressed downwards.

5. The method of claim 1, wherein in step S4, a negative pressure of 1000Pa is maintained after the vacuum is pulled.

6. The method according to claim 1, wherein in step S4, the pressurization pressure is set to 0.5t to 1.2 t.

7. The method as claimed in claim 1, wherein in step S4, the heating program is set to 50 ℃/min to 350 ℃, 100 ℃/min to 450 ℃ to 550 ℃.

8. The method of claim 1, wherein in step S4, the temperature is reduced to below 50 ℃ at 50 ℃/min after spark plasma sintering, the heating procedure is turned off, and the vacuum pump is turned off.

9. A glass-ceramic solidified body obtained according to the method of any one of claims 1-8.

10. The glass-ceramic cured body according to claim 9, comprising a ceramic mixture bonded by iron phosphate glass, the ceramic mixture being a mixture of fluoro (chloro) apatite, fluoro (chloro) apatite and monazite.

11. The glass-ceramic cured body according to claim 10, wherein the chemical structural formulae of the fluoro (chloro) apatite, the fluoro (chloro) apatite and the monazite are each M₅(PO₄)₃F，M₅(PO₄)₃Cl and NPO₄Wherein M is metal cation of Li, Ca, Ba, Sr, Cs, La, U and Zr, and N is cation of Ce, Th, U and Pu.