Plasma device and method for treating radioactive waste by adopting liquid metal

Abstract

The invention discloses a plasma device and method for treating radioactive waste through liquid metal. A method for treating radioactive waste through liquid metal comprises the following steps that tin is put into a plasma furnace, and the tin is molten into a liquid state under the action of plasma jet to form a liquid metal layer; the radioactive waste resin is dried and crushed into particles, the particles are sent into the liquid metal layer through nitrogen, oxygen is introduced into the liquid metal layer, a glass solution layer is generated on the liquid metal layer, tail gas is decomposed out, and after the glass solution layer is cooled, vitrified solids are obtained. According to the method, volume reduction and innocent treatment of the radioactive waste resin can be simply, conveniently and efficiently achieved, meanwhile, coking is prevented from blocking a furnace body, and the ignition loss rate of bottom slag is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear reactions, and in particular to a plasma device and method for treating radioactive waste using liquid metal. Background Art

[0002] Ion exchange resins have been widely used in nuclear military industry, nuclear power and other fields. Used waste ion exchange resins belong to medium and low-level radioactive wastes, containing radioactive nuclides such as 137Cs, 60Co, and 63Ni. With the continuous development of nuclear energy, the production of radioactive waste ion exchange resins in my country has been increasing year by year. However, the treatment and disposal scheme for radioactive waste ion exchange resins in my country is not perfect. Currently, two main methods are adopted: temporary storage and cement solidification. Among them, temporary storage only postpones the problem and does not effectively deal with resin waste; cement solidification belongs to the capacity expansion disposal technology, which does not conform to the principle of waste minimization; in addition, long-term temporary storage and cement solidification of ion exchange resins have certain safety hazards, and the application prospects are not optimistic.

[0003] In recent years, China has also introduced technologies such as hot overpressure, high-integral containers, incineration, steam reforming, supercritical water oxidation and Fenton oxidation to treat radioactive waste ion exchange resins. However, these technologies still have the possibility of resin swelling and radiation degradation, the long-term stability after disposal is unknown, and the treatment process has certain defects.

[0004] Radioactive waste ion exchange resins are organic matter. In order to improve the safety of final disposal, it is necessary to inorganicize the resins before final disposal. High-temperature pyrolysis technology is one of the most effective treatment solutions for organic waste. It has the advantages of high volume reduction ratio and product inorganicization. At the same time, it can separate pyrolysis and incineration, which can effectively avoid the volatilization of some radioactive nuclides, thereby greatly reducing the difficulty of tail gas purification. Therefore, radioactive waste pyrolysis treatment technology is an ideal method for treating radioactive waste ion exchange resins. At present, this technology has been applied in Germany, the United States and other countries. my country has a good research foundation in radioactive waste pyrolysis treatment technology. At present, three sets of conventional low-level combustible solid waste pyrolysis and incineration devices have been established and are in operation.

[0005] Plasma high-temperature melting glass solidification technology has the advantages of wide application range, fast reaction speed, low secondary pollution, small tail gas volume and compact equipment in the process of radioactive waste pyrolysis and gasification. It can realize the decomposition and gasification combustion of organic waste, high-temperature gasification and melting of inorganic waste and solidification of radioactive nuclides in one system, greatly reducing the volume of waste and obtaining a stable final waste body. Therefore, plasma high-temperature gasification and melting technology can be applied to the treatment of nuclear power plants, nuclear facility operations and decommissioning waste. The engineering application of this technology will provide a new way for the treatment and disposal of radioactive waste.

[0006] At present, plasma technology is still used to treat low- to medium-level radioactive wastes such as plastics, rubber, cotton products and paper products, which are mainly organic. The main radionuclides in the wastes include: 137Cs, 90Sr, 60Co, Ru, 3H, U, Pu, etc., which are mainly low-level.

[0007] In the patents or documents that have been published so far, there are still many problems in the process of treating radioactive waste resin by plasma high-temperature gasification and melting treatment technology: 1. Generally, gasification (or incineration) is adopted first, and then the gasified bottom ash is plasma melted to achieve the effect of glass solidification; this type of furnace and process do have a good effect in achieving radioactive waste volume reduction; but at the same time, it should be noted that gasification first and then melting make the process more complicated. 2. In the plasma gasification stage, during the organic matter reaction process, coking is easy to block and cause furnace shutdown; at the same time, the gasification process is uneven, which is easy to cause a high reduction rate of the bottom ash after the reaction (the national standard requires a reduction rate of 5%). It is difficult to meet this requirement in actual engineering operation, and a reduction rate of 10% or even more often occurs, which leads to a large amount of residual carbon entering the next melting link, and the residual carbon has a high melting point, and it is difficult to be melted to form a glass body in the melting stage; this part of the problem directly affects the volume reduction rate, and even the residual carbon can cause poor fluidity of the molten pool and even block the discharge port.

[0008] Based on the above problems, there is an urgent need for a device and method for treating radioactive waste resin in an integrated manner, so as to simply and efficiently achieve volume reduction and harmless treatment of radioactive waste resin, while avoiding coking and clogging of the furnace body and reducing the ignition rate of bottom ash. Summary of the invention

[0009] The technical problem to be solved by the present invention is that the prior art lacks a method that can simply and efficiently treat radioactive waste resin, avoid the problem of furnace shutdown caused by coking and blockage, and reduce the ignition loss rate of bottom ash.

[0010] The first purpose of the present invention is to provide a method for treating radioactive waste using liquid metal, which can simply and efficiently treat radioactive waste resin, avoid the problem of furnace shutdown caused by coking and clogging, and reduce the ignition loss rate of bottom ash, thereby solving the problems of complex process for treating radioactive waste resin in the prior art, easy coking and clogging leading to furnace shutdown, and high ignition loss rate of bottom ash.

[0011] The second object of the present invention is to provide a plasma device for treating radioactive waste using liquid metal, which can be used in conjunction with the above method to reduce the volume of radioactive waste resin and render it harmless.

[0012] The present invention is achieved through the following technical solutions:

[0013] The present invention provides a method for treating radioactive waste using liquid metal, comprising the following steps:

[0014] Tin is placed in the plasma furnace, and under the action of the plasma jet, the tin melts into liquid to form a liquid metal layer;

[0015] The radioactive waste resin is dried and crushed into particles, which are sent into the liquid metal layer via nitrogen, and oxygen is introduced into the liquid metal layer to form a glass solution layer on the liquid metal layer and decompose the tail gas. After the glass solution layer is cooled, a vitrified solid is obtained.

[0016] As a possible design, the temperature of the plasma jet is 2000-3000°C.

[0017] As a possible design, in the above liquid metal layer, the gas pressure in the furnace is controlled to be -0.3 to -0.1 KPa.

[0018] As a possible design, the radioactive waste resin is dried by drying, the particle size of the radioactive waste resin particles is 0.5 to 2 mm, the nitrogen flow rate is 50 to 100 m / s, and the radioactive waste resin particles sent into the liquid metal layer by nitrogen are located at a height of 1 / 4 to 1 / 2 of the liquid metal layer from the bottom of the furnace. The temperature of the glass solution layer is 1000 to 1400°C, and oxygen is specifically introduced from the bottom of the furnace.

[0019] As a possible design, the temperature of the above glass formula layer is between 400 and 600°C.

[0020] As a possible design, glass formula materials are also added to the glass solution layer, and the glass formula materials are stirred after being added to form a glass formula layer on the glass solution layer. After the glass formula layer and the glass solution layer are cooled, a vitrified solid is obtained.

[0021] The present invention also provides a plasma device for treating radioactive waste using liquid metal, comprising:

[0022] Plasma furnaces, which are hollow inside and are used to contain tin and radioactive waste resin;

[0023] A feed port, installed on the plasma furnace, for feeding tin and glass formula materials into the plasma furnace;

[0024] A plasma torch is inserted into the plasma furnace and is used to emit a plasma jet to heat the plasma furnace;

[0025] A feed pipe, installed on the plasma furnace, used to feed radioactive waste resin into the plasma furnace;

[0026] The exhaust pipe is installed on the top of the plasma furnace to discharge the reaction exhaust gas;

[0027] An oxygen blowing pipe is installed at the bottom of the plasma furnace and is used to introduce oxygen into the plasma furnace;

[0028] A liquid metal drain port is installed at the bottom of the plasma furnace to drain the liquid metal;

[0029] The glass solution drain port is connected to the middle of the side of the plasma furnace and is used to drain the glass solution.

[0030] As a possible design, the plasma device further includes a material distributor disposed in the plasma furnace, and the material distributor is located below the feed inlet.

[0031] As a possible design, the above-mentioned material distributor is conical.

[0032] As a possible design, the plasma furnace comprises an upper section, a middle section and a lower section.

[0033] The feed inlet and exhaust pipe are installed in the upper section;

[0034] The plasma torch and the glass solution drain are installed in the middle section;

[0035] The inner diameter of the lower section is smaller than that of the middle section, and the feed pipe, oxygen blowing pipe and liquid metal discharge port are all installed in the lower section.

[0036] As a possible design, there are multiple feeding tubes and plasma torches.

[0037] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0038] The present invention firstly puts tin into a plasma furnace and melts it into liquid, and then puts radioactive waste resin into the liquid metal through nitrogen. Since nitrogen is an inert gas, it can prevent the radioactive waste resin from reacting with the outside world. When it is put into the liquid metal, the chemical property of tin is inactive and it hardly participates in the reaction of water and oxygen. Therefore, obvious stratification will appear in the furnace body. In addition, since nitrogen disturbs the internal flow field of the liquid metal, the temperature field inside the entire liquid metal layer is more uniform, which can make the temperature uniform and eliminate the problem of low-temperature dead zone. It can also promote the momentum transfer, heat energy transfer and mass transfer between the waste resin and the liquid metal molten pool, making the reaction more intense and the pyrolysis more thorough, which can effectively improve the efficiency and yield of the whole process. At the same time, oxygen is blown into the bottom of the plasma furnace. In the dynamic equilibrium of the chemical reaction, a certain amount of oxygen atoms or oxygen ions are dissolved in the solution. The reaction rate of dissolved oxygen and carbon is faster than the reaction rate of solid carbon and oxygen in the air. 1 to 2 orders of magnitude, so the carbon and oxygen in the waste resin quickly generate CO gas to escape from the liquid metal layer. At the same time, the liquid metal can be temperature-controlled by blowing in oxygen to reasonably control the liquid temperature inside the layer to ensure the safety and rapid progress of the reaction. At the same time, the H component in the waste resin forms H2, which forms a synthesis gas with the above-mentioned CO and escapes from above the liquid metal layer; the organic matter in the waste resin generates H2 and CO gas to overflow, and the remaining inorganic matter melts into a glass solution layer. In this layer, a large number of nuclides and harmful components are wrapped in the glass solution to form a vitreous body. After reaching a certain amount, the glass solution can be discharged. After the glass solution flows out and is quenched with water, a solid vitreous body is formed. The vitreous body can form a stable tetrahedral structure, and most of the volatile heavy metals (Hg, Cd, Pb, As, etc.) and radioactive nuclides (Cs, Sr, etc.) are solidified inside the vitreous body, achieving the effect of radioactive nuclide glass solidification, thereby achieving the purpose of harmless radioactive waste resin.

[0039] The whole method of the present invention does not need to gasify the waste resin first and then melt it, which can simplify the complicated processing steps, greatly reduce the workload of operators, and effectively improve the work efficiency of harmless treatment of radioactive waste.

[0040] The present invention will not have the problem of coking during the reaction process, the bottom is filled with liquid metal, and there will be no problems of blockage and shutdown. In addition, during the reaction process, there are nitrogen and oxygen disturbances, which can improve the uniformity of the reaction and effectively reduce the ignition rate of the bottom slag after the reaction. There is almost no residual undecomposed organic matter, and the carbon atom conversion rate is as high as 98-99%. Almost all organic matter is converted into the simplest inorganic matter - dissolved carbon or CO gas and H2.

[0041] The device of the present invention directly combines pyrolysis, gasification and melting into one process, and completes the pyrolysis, gasification and melting processes in a centralized manner inside the liquid metal melting pool, turning two-step processing into one-step processing, which is a revolutionary innovation in the field of radioactive waste treatment; it greatly simplifies the intermediate links, improves environmental protection performance, and reduces treatment energy consumption; it has the advantages of a wide range of applications, fast reaction speed, low secondary pollution, small tail gas volume, and compact equipment, and can realize the decomposition, gasification and combustion of radioactive waste resins, high-temperature gasification and melting of inorganic wastes, and solidification of radioactive nuclides in one system, greatly reducing the volume of waste and obtaining a stable vitreous body. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0043] Figure 1 It is a schematic cross-sectional structure diagram of a plasma device for treating radioactive waste using liquid metal according to the present invention;

[0044] Figure 2 The figure is a schematic diagram of the structure of the plasma device for treating radioactive waste using liquid metal according to the present invention.

[0045] Marks and corresponding parts names in the attached drawings:

[0046] 1-feeding port; 2-plasma furnace; 21-upper section; 22-middle section; 23-lower section; 3-plasma torch; 4-glass formula layer; 5-glass solution layer; 6-feeding pipe; 7-exhaust pipe; 8-mixer; 9-bottom oxygen blowing pipe; 10-liquid metal layer; 11-liquid metal drain port; 12-glass solution drain port. DETAILED DESCRIPTION

[0047] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0048] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. In addition, it will be appreciated by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] In the description of the present invention, the directions or positional relationships indicated by terms such as “front”, “rear”, “left”, “right”, “up”, “down”, “vertical”, “horizontal”, “high”, “low”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present invention.

[0050] The present invention provides a method for treating radioactive waste using liquid metal, comprising the following steps:

[0051] S1. Put tin into a plasma furnace. Under the action of the plasma jet, the tin melts into liquid to form a liquid metal layer 10.

[0052] First, tin is an inactive metal. The molten tin provides the heat required for the subsequent addition of radioactive waste resin, strengthens the pyrolysis and gasification reaction of radioactive waste particles in the liquid metal solution layer, makes the reaction more intense, and the pyrolysis more thorough. Second, as a liquid contact medium and flow matrix, it evenly reacts everywhere, promotes the contact reaction between the glass solution and the glass formula, accelerates the formation of the glass solution, and strengthens the effect of radionuclide glass solidification. Third, it can act as a carbon solution, oxygen dissolver and carbon-oxygen rapid reaction carrier. Since the internal temperature of liquid metal is as high as 1200°C, after contacting with radioactive waste resin, especially in the immersed state, organic molecules are rapidly cracked within tens of milliseconds to form carbon products. Carbon atoms dissolve into the liquid metal (tin), and hydrogen atoms combine to form hydrogen molecules to escape from the molten pool; while the bottom oxygen is blown into the liquid metal molten pool. In the dynamic equilibrium of chemical reactions, a certain amount of oxygen atoms or oxygen ions are dissolved in the solution. The reaction rate of dissolved oxygen and carbon is 1 to 2 orders of magnitude faster than that of solid carbon and oxygen in the air. CO gas is quickly generated and escapes from the molten pool, and is mixed with H2 formed by the cracking of other organic matter to form synthesis gas. Fourth, it can also act as a catalyst, dispersant, etc.

[0053] S2. Dry the radioactive waste resin and crush it into particles, send it into the liquid metal layer 10 via nitrogen, and introduce oxygen into the liquid metal layer 10 to generate a glass solution layer 5 on the liquid metal layer 10, and decompose the tail gas. After the glass solution layer 5 is cooled, a vitrified solid is obtained.

[0054] After the radioactive waste resin is dried, the moisture therein is discharged, which can facilitate subsequent reactions. By fully breaking it up, the contact area between the waste resin and the reactants can be increased, and the reaction speed and efficiency can be improved. The waste resin is sent into the liquid metal through nitrogen to avoid contact with the outside world. At the same time, since the nitrogen maintains a high flow rate, while ensuring that the nitrogen can penetrate to the bottom of the furnace, under the blowing of the high-speed jet, the flow field disturbance inside the liquid metal layer 10 is also enhanced, making the temperature distribution in the liquid metal layer 10 more uniform, providing process intensification for the pyrolysis and gasification reactions of the radioactive waste resin in the liquid metal solution layer, making the reaction more intense and the pyrolysis more thorough, which can effectively improve the efficiency and yield of the entire process. At the same time, oxygen is introduced into the liquid metal layer 10 from the bottom of the furnace body, and the oxygen is blown into the liquid molten pool. In the dynamic equilibrium of the chemical reaction, a certain amount of oxygen atoms or oxygen ions are dissolved in the solution. The reaction rate of dissolved oxygen and carbon is 1 to 2 orders of magnitude faster than the reaction rate of solid carbon and oxygen in the air. Therefore, the carbon and oxygen in the waste resin quickly generate CO gas and escape from the liquid metal layer 10; the temperature of the liquid metal layer 10 can also be controlled by the flow rate of the injected gas, and the liquid temperature inside the layer can be reasonably controlled to ensure the safety and rapid progress of the reaction; at the same time, the H component in the waste resin forms H2 to overflow.

[0055] After the waste resin is pyrolyzed, the organic components will form CO and H2 gases, while the inorganic components will form a glass solution. Since the density of the glass solution is lower than that of the liquid metal, the glass solution is located above the liquid metal layer 10, and the glass solution can be discharged. After it is cooled, a vitreous body will be formed. The vitreous body will form a stable tetrahedral structure, and most of the volatile heavy metals (Hg, Cd, Pb, As, etc. and radionuclides Cs, Sr, etc.) will be solidified inside the vitreous body, achieving the effect of radionuclide glass solidification, thereby achieving the purpose of harmless radioactive waste resin. At the same time, harmful components such as S and Cl in the waste resin are also solidified in the vitreous body in large quantities.

[0056] The method of the present invention treats waste resin. Due to the ultra-high temperature reaching over 1200°C, organic matter is ultra-high temperature cracked into monatomic inorganic matter or diatomic gas molecules without any complex organic matter or intermediate products, such as the relatively deadly intermediate product dioxin, or organic matter such as tar. The method greatly improves the environmental protection effect and reduces the pressure of the back-end flue gas system treatment.

[0057] In some embodiments of the present invention, the above method also includes adding glass formula materials into the glass solution layer 5, and stirring the glass formula materials after adding them, so as to generate a glass formula layer 4 on the glass solution layer 5, and after the glass formula layer 4 and the glass solution layer 5 are cooled, a vitrified solid is obtained.

[0058] The added glass formula material can promote the formation of glass solution and enhance the effect of radionuclide glass solidification. Moreover, stirring after adding the glass formula material can promote more glass solution to react with the glass formula material, thereby accelerating the generation speed of vitrified solid.

[0059] Preferably, the feed ratio of the glass formula material to the radioactive waste resin is 1:20. Under this feed amount, more glass solution can be caused to react with the glass formula material, and the glass formula material and the radioactive waste resin are fed synchronously.

[0060] In some embodiments of the present invention, the plasma jet temperature is 2000-3000°C.

[0061] The high temperature flame length can be adjusted to 300-1000 mm as required. After the tin is added, the plasma torch 3 is started to heat the base material tin by using the high temperature plasma jet. After a period of time, the base material is melted into a liquid molten pool to form a liquid metal layer 10.

[0062] In some embodiments of the present invention, in the liquid metal layer 10, the gas pressure in the furnace is controlled to be -0.3 to -0.1 KPa.

[0063] In some embodiments of the present invention, the radioactive waste resin is dried by baking, the particle size of the radioactive waste resin particles is 0.5 to 2 mm, the nitrogen flow rate is 50 to 100 m / s, and the radioactive waste resin particles sent into the liquid metal layer 10 by nitrogen are located at a height of 1 / 4 to 1 / 2 of the liquid metal layer 10 from the bottom of the furnace. The temperature of the glass solution layer 5 is 1000 to 1400°C, and oxygen is specifically introduced from the bottom of the furnace.

[0064] When the particles of the waste resin are 0.5 to 2 mm, the contact area between the waste resin and the reactants can be increased, thereby improving the reaction efficiency; when the nitrogen flow rate is high, the liquid metal layer 10 can be broken and the waste resin can be sent into the liquid metal layer 10 to facilitate the reaction of the waste resin; oxygen is introduced from the bottom of the furnace body to ensure that the waste resin fully reacts with it.

[0065] In some embodiments of the present invention, the temperature of the glass formula layer 4 is between 400 and 600°C.

[0066] At this temperature, the reaction efficiency of the glass formula can be improved, the formation of the proportional solution can be accelerated, and the curing effect of the subsequently obtained vitrified solid can be better.

[0067] In some embodiments of the present invention, the temperature of the exhaust gas is 400-600°C.

[0068] In the prior art, the exhaust temperature is above 1000°C, and a large amount of volatile heavy metals and related nuclides are transferred into the flue gas. At the same time, the high-temperature flue gas also brings about problems such as flue wear and burning, and the economic efficiency is relatively poor. The present invention adopts a layered structure to treat the waste resin, thereby reducing the exhaust gas temperature at the exhaust port 7, reducing the difficulty of flue gas system treatment, and making it less likely to be worn and burned by high-temperature exhaust gas. It also inhibits the migration of nuclides and solidifies more volatile heavy metals inside the glass body, solving the solidification problem of volatile heavy metals.

[0069] In addition, the tail gas of the present invention not only reduces the volume and harmlessly treats the radioactive waste, but also can further process the tail gas to obtain high-end energy synthesis gas, which can be fully utilized.

[0070] The present invention also provides a plasma device for treating radioactive waste using liquid metal, comprising a plasma furnace 2, a feed port 1, a plasma torch 3, a feed pipe 6, an exhaust pipe 7, an oxygen blowing pipe 9, a liquid metal emptying port 11 and a glass solution emptying port 12. The interior of the plasma furnace 2 is hollow, and is used to accommodate tin and radioactive waste resin. It is made of heat-resistant material and can withstand high temperatures of 2000 to 3000°C. The top of the plasma furnace 2 is connected with a feed port 1 and an exhaust pipe 7, the side wall is connected with a plasma torch 3 and a glass solution emptying port 12, and the bottom is connected with a feed pipe 6, an oxygen blowing pipe 9 and a liquid metal emptying port 11. The feed port 1 is vertically set up at the top of the plasma furnace 2, and is used to put tin and glass formula materials into the plasma furnace 2. The plasma torch 3 is obliquely inserted into the plasma furnace 2, and the position is adjustable. It is provided with a pneumatic actuator and can move up and down, so that the high-temperature flame length can be adjusted to 300 to 1000 mm as needed. It can emit a high-temperature plasma jet to heat the plasma furnace 2. The feed pipe 6 is installed at the bottom of the side wall of the plasma furnace 2, and is obliquely inserted into the plasma furnace 2, and is used to feed the radioactive waste resin into the liquid metal layer 10 after the tin is melted; and because the nitrogen will blow the waste resin into the liquid metal, the flow of the liquid metal can be accelerated under the disturbance of the nitrogen, and the temperature of the molten pool can be evened. The exhaust pipe 7 is installed at the top of the plasma furnace 2. After the waste resin reacts, CO and H2 will be generated, which will be separated from the glass solution and the liquid metal and rise to the top of the plasma furnace 2, and discharged through the exhaust pipe 7. The exhaust temperature is about 400-600°C. The exhausted gas can be reused after treatment, and the proportion of synthetic gas in the exhausted gas is more than 90%. The oxygen blowing pipe 9 is installed at the bottom of the plasma furnace 2. The bottom of the plasma furnace 2 is filled with liquid metal, and the waste resin will be put into the liquid metal layer 10. Oxygen is introduced from the bottom of the plasma furnace 2. The oxygen will first dissolve in the liquid metal. The reaction rate of dissolved oxygen and carbon is 1 to 2 orders of magnitude faster than the reaction rate of solid carbon and oxygen in the air. CO gas is quickly generated and escapes from the molten pool, and is mixed with hydrogen formed by the cracking of other organic matter to form synthesis gas; at the same time, due to the disturbance of oxygen, the fluidity of the liquid metal is enhanced, and the temperature in the molten pool is uniform, which solves the problem of the center of the molten pool and avoiding large temperature differences in the plasma melting stage in the prior art. The liquid metal drain port 11 is installed at the bottom of the plasma furnace 2, and part of the liquid metal can be discharged regularly to ensure the stable operation of the plasma device. The glass solution drain port 12 is connected to the middle of the side of the plasma furnace 2 and is used to discharge the glass solution.

[0071] In some embodiments of the present invention, the plasma device further comprises a material distributor 8 disposed in the plasma furnace 2, and the material distributor 8 is located below the feed port 1. After the glass formula is put in, the glass formula will fall on the material distributor 8. During the continuous rotation of the material distributor 8, the formula will fall evenly on the glass solution layer 5 due to the action of centrifugal force during the falling process, forming a uniform glass formula layer 4, ensuring that the liquid level of the glass formula layer 4 on the glass solution layer 5 is very uniform, which is beneficial to the mixing uniformity of the formula and the glass solution, enhances the solidification effect of the nuclide glass, and solves the problems of uneven distribution of the solvent added to the furnace and unsatisfactory melting effect in the prior art.

[0072] In some embodiments of the present invention, the material distributor 8 is conical in shape. When the conical structure rotates, the glass formula material can be evenly sprinkled onto the glass solution layer 5 as much as possible.

[0073] In some embodiments of the present invention, the plasma furnace 2 includes an upper section 21, a middle section 22 and a lower section 23. The feed port 1 and the exhaust pipe 7 are both installed in the upper section 21, which is conducive to feeding and exhaust gas discharge. The plasma torch 3 and the glass solution emptying port 12 are both installed in the middle section 22. The plasma torch 3 is higher than the glass solution emptying port 12, which can ensure the heating effect of the solution at the bottom. The glass solution emptying port 12 is located at the bottom of the middle section 22, which can facilitate the discharge of the glass solution. The inner diameter of the lower section 23 is smaller than the inner diameter of the middle section 22, and its shape is funnel-shaped, which is convenient for controlling the volume of the liquid metal, and at the same time ensures that the material coming in from the feed pipe 6 can be in contact with most of the liquid technical metal to enhance the reaction. The feed pipe 6, the oxygen blowing pipe 9, and the liquid metal emptying port 11 are all installed in the lower section 23.

[0074] In some embodiments of the present invention, there are multiple feed pipes 6 and plasma torches 3. Preferably, there are two feed pipes 6 and plasma torches 3, and the two feed pipes 6 and plasma torches 3 are symmetrically arranged, so as to facilitate uniform feeding and heating.

[0075] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for treating radioactive waste using liquid metal, characterized in that: The steps include: Tin is placed in the plasma furnace, and under the action of the plasma jet, the tin melts into liquid to form a liquid metal layer; The radioactive waste resin is dried and crushed into particles, which are sent into the liquid metal layer via nitrogen, and oxygen is introduced into the liquid metal layer to form a glass solution layer on the liquid metal layer and decompose the tail gas. After the glass solution layer is cooled, a vitrified solid is obtained.

2. A method for treating radioactive waste using liquid metal according to claim 1, characterized in that: The plasma jet temperature is 2000-3000°C.

3. The method for treating radioactive waste using liquid metal according to claim 1, characterized in that: In the liquid metal layer, the gas pressure in the furnace is controlled to be -0.3 to -0.1 KPa.

4. The method for treating radioactive waste using liquid metal according to claim 1, characterized in that: The radioactive waste resin is dried by drying, the particle size of the radioactive waste resin particles is 0.5-2 mm, the nitrogen flow rate is 50-100 m / s, the radioactive waste resin particles sent into the liquid metal layer by nitrogen are located at a height of 1 / 4-1 / 2 of the liquid metal layer from the bottom of the furnace, the temperature of the glass solution layer is 1000-1400°C, and the oxygen is specifically introduced from the bottom of the furnace.

5. The method for treating radioactive waste using liquid metal according to claim 1, characterized in that: The temperature of the glass formula layer is between 400 and 600°C.

6. The method for treating radioactive waste using liquid metal according to claim 1, characterized in that: The glass solution layer is also added with glass formula materials, and stirred after the glass formula materials are added to form a glass formula layer on the glass solution layer. After the glass formula layer and the glass solution layer are cooled, a vitrified solid is obtained.

7. A plasma device for treating radioactive waste using liquid metal, characterized in that: include Plasma furnaces, which are hollow inside and are used to contain tin and radioactive waste resin; A feed port, installed on the plasma furnace, for feeding tin and glass formula materials into the plasma furnace; A plasma torch is inserted into the plasma furnace and is used to emit a plasma jet to heat the plasma furnace; A feed pipe, installed on the plasma furnace, used to feed radioactive waste resin into the plasma furnace; The exhaust pipe is installed on the top of the plasma furnace to discharge the reaction exhaust gas; An oxygen blowing pipe is installed at the bottom of the plasma furnace and is used to introduce oxygen into the plasma furnace; A liquid metal drain port is installed at the bottom of the plasma furnace to drain the liquid metal; The glass solution drain port is connected to the middle of the side of the plasma furnace and is used to drain the glass solution.

8. The plasma device for treating radioactive waste using liquid metal according to claim 7, characterized in that: It also includes a material distributor arranged in the plasma furnace, and the material distributor is located below the feed inlet.

9. The plasma device for treating radioactive waste using liquid metal according to claim 8, characterized in that: The material distributor is conical.

10. The plasma device for treating radioactive waste using liquid metal according to claim 7, characterized in that: The plasma furnace comprises an upper section, a middle section and a lower section. The feed inlet and the exhaust pipe are both installed in the upper section; The plasma torch and the glass solution drain port are both installed in the middle section; The inner diameter of the lower section is smaller than that of the middle section, and the feed pipe, oxygen blowing pipe and liquid metal discharge port are all installed in the lower section.

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