Preparation method of melt cold crucible wall

Abstract

The invention discloses a preparation method of a melt cold crucible wall. The preparation method comprises the following steps: determining to-be-tested melt material powder contained in a test of a melt cold crucible; selecting components of melt material powder used for preparing the melt cold crucible wall according to the components of the to-be-detected melt material powder; preparing a pasty mixture based on the melt material powder; the pasty mixture is smeared in a gap between adjacent cold crucible cooling pipes, and a cold crucible wall is formed; a heating pipe is fixed in the wall of the cold crucible; and the heating pipe is heated, so that the wall of the cold crucible is dried. The method can greatly reduce the influence of partial melting of the cold crucible wall on the test, and has the advantages of low economic cost, simplicity and convenience in operation, high reliability and the like compared with a traditional cold crucible wall preparation method.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear fuel element preparation, and particularly relates to a method for preparing a molten material cold crucible wall. Background Art

[0002] Mastering the physical properties of molten materials is of great significance for both the in-vessel retention strategy (IVR) and the ex-vessel retention strategy (EVR) of molten materials. To obtain more real and reliable physical property data of molten materials, high-temperature molten material measurement devices are often used in research for prototype material tests. Liu Yusheng from the Nuclear and Radiation Safety Center of the Ministry of Environmental Protection compared and elaborated on classic molten material test benches such as COPO, UCLA, ACOPO, RASPLAV, MASCA, and LIVE in the article "Research on the Test Bench for Molten Material Characteristics". Among them, the cold crucible and inductive heating design of MASCA enable better acquisition of the physical properties of molten salts; Patent CN220270053U designed a water-cooled copper crucible with a split structure and a suspension melting device, which also uses a water-cooled crucible and an induction coil to heat the molten material.

[0003] In summary, the design of a cold crucible and electromagnetic induction heating has many advantages such as simulating the process of contact and reaction between real prototype materials and sacrificial materials, measuring the temperature of the prototype molten pool and the erosion rate of the sacrificial material, and supporting gas production analysis during the reaction process and erosion result detection. It will become the mainstream research and development direction of high-temperature molten material physical property measurement devices in the future. In the laboratory research test of molten material physical properties using a molten material measurement device with a cold crucible and electromagnetic induction heating design, minimizing interference with molten material and the need for multiple tests has become the key. If the cooling tube of the cold crucible uses a non-metallic material, it can reduce interference with inductive coil heating, but its strength and service life will be limited, and it is difficult to meet the requirements of multiple test sections; if the cooling tube material of the cold crucible is a metal, such as metal copper or titanium alloy, it has advantages in terms of strength and installation, but the disadvantage is that electromagnetic induction will occur, affecting inductive coil heating and wasting a certain amount of heating power, but this method is feasible.

[0004] The existing patent CN111562282A discloses a test device and method for simulating the transient reaction of molten materials at high temperatures, and specifically discloses a method for forming a crucible by using a water-cooled crucible and filling the gaps of the cooling water pipes with zirconia or uranium oxide powder or a mixture of the two.

[0005] The existing patent CN116130126A discloses a compact molten material transient reaction simulation device and simulation method, which relates to the technical field of nuclear industry research. The specific scheme is as follows: It includes a water-cooled crucible, a heating mechanism and a shielding mechanism sleeved on the water-cooled crucible. A cover plate is provided at the top of the water-cooled crucible, and a temperature measurement channel and a feeding channel are provided on the cover plate. The cover plate is respectively connected to a gas supply system for providing an inert gas with a density greater than that of air and a monitoring system for measuring the oxygen content. The shielding mechanism is located between the heating mechanism and the water-cooled crucible, and the shielding mechanism is slidably connected to the cover plate to move up and down. It designs an inverted U-shaped water-cooled pipe, and zirconia is sintered on the inner and outer sides of the crucible side wall as a protective layer.

[0006] However, research has found that the above method has deficiencies in the preparation process of the cold crucible wall: 1) The ratios of the molten material powders such as zirconia or uranium oxide involved in different test conditions are different, and there are even differences in the types of the material powders. The large difference between the materials used for the cold crucible wall preparation and the molten material will affect the accuracy of the test; 2) During the preparation process of the cold crucible wall, even if a small amount of silicate solution is added, it is still impossible to ensure the viscosity and plasticity of the mixed paste. Due to reasons such as the limitation of the material particle size, the defect of the silicate itself, and the limitation of the operation method, it is often difficult to prepare the cold crucible wall or even impossible to prepare it successfully; 3) Traditional drying methods, such as drying with an electric air heater or natural air drying, not only take a long time and have a poor drying effect, but also are prone to cracking of the cold crucible wall due to uneven heating. Summary of the Invention

[0007] Based on the above technical problems, the present invention proposes a method for preparing a cold crucible wall of a molten material, which solves the problems of low test accuracy, difficult preparation of the cold crucible wall and poor drying effect caused by the composition of the molten material powder in the prior art.

[0008] A method for preparing a cold crucible wall of a molten material includes:

[0009] Determine the molten material powder to be tested accommodated in the test of the cold crucible of the molten material;

[0010] Select the composition of the molten material powder used to prepare the cold crucible wall of the molten material according to the composition of the molten material powder to be tested;

[0011] Use the molten material powder to prepare a paste mixture;

[0012] Apply the paste mixture to the gap between adjacent cold crucible cooling pipes to form a cold crucible wall;

[0013] Fix a heating pipe inside the cold crucible wall;

[0014] Heat the heating pipe to realize the drying treatment of the cold crucible wall.

[0015] Further, the composition of the molten material powder is the component in the molten material powder to be measured with a melting point higher than 2400 °C, and the composition of the molten material powder includes one or more of zirconia, uranium oxide, chromium oxide and magnesium oxide.

[0016] Further, under the molten density inversion oxide layer test, the composition of the selected molten material powder includes uranium oxide and zirconia, and the mixing ratio of the uranium oxide to the zirconia is (73±5):(22±5).

[0017] Further, under the molten oxide phase final component simulation test, the composition of the selected molten material powder includes uranium oxide, zirconia and chromium oxide, and the mixing ratio of the uranium oxide, the zirconia and the chromium oxide is (54±5):(22±5):(10±5).

[0018] Further, a paste mixture is prepared by using the molten material powder, including: mixing the molten material powder, an aqueous sodium silicate solution and silica sol to form a paste mixture.

[0019] Further, mixing the molten material powder, an aqueous sodium silicate solution and silica sol to form a paste mixture, including: mixing the molten material powder, the aqueous sodium silicate solution and silica sol according to a volume ratio of (4±1):(1±0.1):(1±0.1) to form a paste mixture.

[0020] Further, the cold crucible cooling tubes are arranged in a circular array, the radius R of the cold crucible cooling tubes satisfies 1 cm ≤ R ≤ 2.5 cm, the thickness U1 satisfies 1 mm ≤ U1 ≤ 2 mm, and the number N1 of the cold crucible cooling tubes satisfies 12 ≤ N1 ≤ 48; the distance M between two adjacent cold crucible cooling tubes satisfies 0.5 cm ≤ M ≤ 3 cm.

[0021] Further, the heating tube is a metal heating tube, and the metal heating tube is composed of a lifting ring, a heating tube and a diversion exhaust pipe. The heating tube includes a first partition and a second partition, and the diversion exhaust pipe is located in the first partition.

[0022] Further, the metal heating tube has the same height as the cold crucible cooling tube, and the wall thickness U2 of the metal heating tube satisfies 2 mm ≤ U2 ≤ 4 mm, and the outer diameter l of the metal heating tube and the inner diameter f of the cold crucible satisfy 0.3f ≤ l ≤ 0.5f.

[0023] Further, the first partition and the second partition have the same height.

[0024] Further, the diversion exhaust pipe is inclined downward at an angle of 45° with the horizontal direction and is arranged in a circumferential array.

[0025] Further, the heating tube is heated to dry the cold crucible wall, including: heating the metal heating tube by an inductive coil heating system.

[0026] Further, the inductive coil heating system is used to heat and dry the lower half area of the crucible wall by heating the second partition of the heating tube, and deliver the heat to the first partition, and the hot air is discharged by the diversion exhaust pipe to heat and dry the upper half area of the cold crucible wall.

[0027] Further, the inductive coil heating system includes a multi-turn inductive coil. The inductive coil is in a spiral shape. The number of turns N2 of the inductive coil satisfies 3 ≤ N2 ≤ 8, the pitch d satisfies 1 cm ≤ d ≤ 3 cm, and the diameter D and the outer diameter g of the cold crucible satisfy D ≥ 1.1g.

[0028] Further, after the paste mixture is applied to the gap between adjacent cold crucible cooling tubes to form a cold crucible wall, it further includes:

[0029] Spray water droplets evenly on the surface of the cold crucible wall and smear the surface to make it evenly smooth.

[0030] Further, heating the metal heating tube by an inductive coil heating system further includes:

[0031] Continuously dry the cold crucible wall for 6 - 12 h. After the surface of the cold crucible wall is dry, evenly apply resin and wind insulating cloth around the surface of the cold crucible wall;

[0032] Continue to dry the cold crucible wall for 1 - 2 h to complete the preparation of the cold crucible wall.

[0033] Based on the above technical solutions, the present invention has at least the following beneficial effects:

[0034] 1. The present invention proposes to select the composition of the molten material powder used to prepare the cold crucible wall of the molten material according to the powder of the molten material to be tested used in the experiment, and mix them for preparing the cold crucible wall. This method can greatly reduce the influence on the experiment caused by partial melting of the cold crucible wall, and has advantages such as low economic cost, simple and convenient operation, and high reliability compared with the traditional cold crucible wall preparation method.

[0035] 2. The present invention proposes to select the components in the powder of the molten material to be measured with a melting point higher than 2400 °C to prepare the cold crucible wall, and proportion the components of the molten material powder according to the test type. While improving the reliability of the cold crucible wall, the material composition ratio of the prepared cold crucible wall is close to that of the molten material powder to be measured, reducing the influence of the partially melted crucible wall on the molten material composition during the test and improving the accuracy of the test results.

[0036] 3. The present invention designs a metal heating tube, which can be heated by the inductance coil system of the high-temperature molten material measuring device. The metal heating tube is provided with a diversion exhaust pipe and a heating area, which can make the cold crucible wall receive heat efficiently and evenly, improve the drying rate and prevent cracking during the drying process.

[0037] 4. By designing the number and radius of the cold crucible cooling tubes, the wall thickness and outer diameter of the metal heating tube, and the number of turns, pitch, diameter and height of the inductance coil, the present invention can ensure that the cold crucible wall is evenly dried for high-temperature melting tests.

[0038] 5. The preparation method of the cold crucible wall proposed by the present invention utilizes the original equipment and instruments of the high-temperature molten material measuring device, such as inductance coils, heating power supplies, cold crucible cooling tubes, etc., greatly reducing the equipment and time costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0040] Figure 1 is a flowchart of a method for preparing a molten material cold crucible wall according to an embodiment of the present invention;

[0041] Figure 2 is a schematic diagram of a molten material cold crucible wall preparation system according to an embodiment of the present invention;

[0042] Figure 3 is a schematic diagram of the structure of a cold crucible cooling tube according to an embodiment of the present invention;

[0043] Figure 4a is a schematic diagram of the structure of a metal heating tube according to an embodiment of the present invention;

[0044] Figure 4b is a schematic diagram of the heat transfer of the heating tube in this embodiment;

[0045] Figure 5 is a schematic diagram of the structure of an inductance coil according to an embodiment of the present invention.

[0046] Among them, the above-mentioned accompanying drawings include the following reference numerals:

[0047] 1. Cold crucible cooling tube; 2. Metal heating tube; 3. Cold crucible wall; 4. Inductive coil; 201. Suspension ring; 202. Heating tube; 203. Diversion exhaust pipe; 210. First partition; 220. Second partition; 221. Main heating area; 222. Secondary heating area. Detailed implementation mode

[0048] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0049] The following further describes the present invention in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present invention.

[0050] Embodiment

[0051] To solve the problems of low test accuracy, difficult preparation of the cold crucible wall, and poor drying effect caused by the powder components of the melt material in the prior art, the present invention proposes a method for preparing a cold crucible wall of a melt. This preparation method uses the melt material powder, inductive coil heating system, cold crucible cooling tube, and metal heating tube used in the high-temperature melt measurement device during the test to prepare the cold crucible wall of the melt.

[0052] As Figure 1 shows the flowchart of the preparation method of an embodiment of the present invention, and this method includes the following preparation steps:

[0053] S1. Determine the melt material powder to be measured contained in the test of the cold crucible of the melt.

[0054] S2. Select the composition of the melt material powder used to prepare the cold crucible wall of the melt according to the composition of the melt material powder to be measured.

[0055] In this embodiment, the composition of the melt material powder is the component in the melt material powder to be measured with a melting point higher than 2400 °C, and the composition of the melt material powder includes one or more of zirconia, uranium oxide, chromium oxide, and magnesium oxide. Components with a melting point lower than 2400 °C, such as alumina, iron oxide, and ferrous oxide, are not selected to improve the reliability of the crucible wall and reduce melting.

[0056] In order to make the composition of the crucible wall as close as possible to the selected melt composition to reduce the influence of the partially melted crucible wall on the melt material composition during the test, the present invention proposes that after initially selecting the composition of the melt material powder used to prepare the cold crucible wall of the melt according to the composition of the melt material powder to be measured, different powders are selected for proportioning according to the test conditions.

[0057] In a specific embodiment of the present invention, under the molten density inversion oxide layer test, the composition of the selected molten material powder includes uranium oxide and zirconium oxide, and the mixing ratio of the uranium oxide to the zirconium oxide is (73±5):(22±5). Under the molten oxide phase final component simulation test, the composition of the selected molten material powder includes uranium oxide, zirconium oxide and chromium oxide, and the mixing ratio of the uranium oxide, the zirconium oxide to the chromium oxide is (54±5):(22±5):(10±5). The above selected material powder components are proportioned to form a molten material powder. It should be understood that the composition of the selected molten material powder may be different in different embodiments, and the mixing ratio refers to the component ratio in the molten material powder to be tested.

[0058] In addition, since the particle size of the molten material powder seriously affects the viscosity and ductility of the formed paste-like molten material, if the particles are too large, a cold crucible wall cannot be made and the production efficiency is seriously affected. In this embodiment, the median particle size D50 of the molten material powder particles ≤ 10 μm, and the maximum particle size D100 ≤ 100 μm.

[0059] S3. Prepare a paste-like mixture using the molten material powder.

[0060] Sodium silicate has good adhesiveness, water resistance and heat resistance, but after being mixed with the molten material powder, not only its viscosity is easily reduced, but also its hardening time is not easy to control. Colloidal silica has strong cementing ability and purification effect. Mixing sodium silicate and colloidal silica together in a certain proportion can form a mixed material with good waterproof performance and moisture resistance. The paste-like mixture formed by mixing with the molten material powder has an ideal effect, and the prepared cold crucible wall has excellent performance.

[0061] Further, preparing a paste-like mixture using the molten material powder includes: mixing the molten material powder, an aqueous sodium silicate solution and colloidal silica to form a paste-like mixture.

[0062] Further, mixing the molten material powder, the aqueous sodium silicate solution and colloidal silica to form a paste-like mixture includes: mixing the molten material powder, the aqueous sodium silicate solution and colloidal silica in a volume ratio of (4±1):(1±0.1):(1±0.1) to form a paste-like mixture. The formed paste-like mixture has good viscosity and plasticity. The cold crucible wall prepared using this paste-like mixture can improve the safety factor while reducing the influence of the cold crucible wall on the molten material test.

[0063] S4. Apply the paste-like mixture to the gap between adjacent cold crucible cooling tubes to form a cold crucible wall.

[0064] As Figure 2The figure shows a schematic diagram of a preparation system for the molten material cold crucible wall of this embodiment. The system includes a cold crucible cooling tube 1, a metal heating tube 2, a cold crucible wall 3, and an inductor coil 4. Figure 2 In it, the cold crucible cooling tubes are arranged in a circumferential array. Since the radius R of the cold crucible cooling tube is too small to achieve the cooling effect or too large to facilitate the preparation of the cold crucible wall, the radius R of the cold crucible cooling tube satisfies 1 cm ≤ R ≤ 2.5 cm, the thickness U1 satisfies 1 mm ≤ U1 ≤ 2 mm, and the number N1 of the cold crucible cooling tubes satisfies 12 ≤ N1 ≤ 48. The spacing M between two adjacent cold crucible cooling tubes satisfies 0.5 cm ≤ M ≤ 3 cm. In this embodiment, the radius R of the cold crucible cooling tube is between 1 cm and 2.5 cm, the thickness U1 is between 1 mm and 2 mm, and the number N1 of the cold crucible cooling tubes is between 12 and 48. It should be understood that in other embodiments of the present invention, the radius of the cold crucible cooling tube can be 1 cm or 2.5 cm or between 1 cm and 2.5 cm, the thickness U1 can be 1 mm or 2 mm or between 1 mm and 2 mm, the number N1 of the cold crucible cooling tubes can be 12 or 48 or between 12 and 48, and the spacing M between two adjacent cold crucible cooling tubes can be 0.5 cm, 3 cm or between 0.5 cm and 3 cm. As Figure 3 It shows the radius R of a single cold crucible cooling tube and the spacing M between two adjacent cold crucible cooling tubes.

[0065] If the cooling tube spacing M is too small, it is not easy for inductive heating; if it is too large, it is also not easy for the preparation of the cold crucible wall; the material of the cold crucible cooling tube can be metal (such as copper, titanium alloy, aluminum alloy, etc.) or non-metal (such as boron nitride, silicon carbide, silicon nitride, alumina, etc.). If metal materials are used, it is convenient in terms of strength and installation, but it will affect the inductive coil heating. If non-metal materials are used, it can reduce the interference with the inductive coil heating, but the strength and service life will be limited; the inside of the cold crucible cooling tube is filled with cooling water (temperature below 60 °C), and the cooling water flow rate v satisfies 0.4 m / s ≤ v ≤ 1.2 m / s.

[0066] S5. Fix the heating tube inside the cold crucible wall.

[0067] In this embodiment, the heating tube used is a metal heating tube. Using a metal heating tube instead of a heating rod design can increase the contact area between the heating tube and the air and improve the heat transfer efficiency. Specifically, the material of the metal heating tube has a melting point higher than 1000 °C and a tensile strength not less than 200 MPa, such as 304 stainless steel, copper alloy, titanium alloy, etc. In this step, the metal heating tube can be fixed inside the cold crucible wall through a lifting ring, so that the metal heating tube is at the central axis position, and its lowest point is flush with the lowest point of the cold crucible cooling tube. It should be understood that in other embodiments, heating tubes of other materials can also be used, such as ceramic heating tubes.

[0068] As shown in Figure 4a FIG. [ID], a schematic structural diagram of the metal heating tube of this embodiment is shown. The metal heating tube is composed of a suspension ring 201, a heating tube 202, and a diversion exhaust pipe 203. The heating tube 202 includes a first partition 210 and a second partition 220. Further, the heights of the first partition and the second partition are the same. The diversion exhaust pipe 203 is located in the first partition 210. Specifically, the height of the metal heating tube is the same as that of the cold crucible cooling tube, and the wall thickness U2 of the metal heating tube satisfies 2 mm ≤ U2 ≤ 4 mm. Considering that if the outer diameter l of the metal heating tube is too large, it is likely to cause the local temperature of the cold crucible wall to rise too fast and crack, and if it is too small, the drying effect cannot be achieved. The outer diameter l of the metal heating tube and the inner diameter f of the cold crucible satisfy 0.3f ≤ l ≤ 0.5f. It should be understood that in other embodiments of the present invention, the wall thickness U2 can be 2 mm or 4 mm or between 2 mm and 4 mm, and the outer diameter l of the metal heating tube and the inner diameter f of the cold crucible satisfy 0.3f ≤ l ≤ 0.5f. As shown in Figure 3 FIG. [ID] shows the outer diameter l of the metal heating tube and the inner diameter f of the cold crucible.

[0069] In a specific embodiment of the present invention, the diversion exhaust pipe is arranged obliquely downward at an angle of 45° with the horizontal direction and is arranged in a circumferential array. Specifically, it can be arranged in one layer of circumference or multiple layers of circumference. This design can make the hot air in the heating tube be discharged evenly, creating a more uniform temperature field.

[0070] S6. Heat the heating tube to realize the drying treatment of the cold crucible wall.

[0071] In this embodiment, the heating tube used is a metal heating tube, and the metal heating tube is heated by an inductive coil heating system. It should be understood that when the heating tube is made of other materials, other heating methods can be used to realize the drying treatment of the cold crucible wall.

[0072] The inductive coil heating system is composed of multiple turns of inductive coils (including but not limited to double-layer water-cooled coils), a power heating cabinet, copper electrodes, etc., and can provide a uniform and stable heating power for the metal heating tube, so that the metal heating tube has a relatively high temperature without local melting damage; the cold crucible cooling tube can provide support for the cold crucible wall during the preparation process. During the test process, a certain flow rate of cooling water is filled in the cold crucible cooling tube, which can provide a certain cooling capacity for the cold crucible wall, so that the cold crucible wall can better wrap the high-temperature melt without melting.

[0073] In this embodiment, the inductive coil heating system is used to heat and dry the lower half of the crucible wall by heating the second partition of the heating tube, and transfer the heat to the first partition, and the hot air is discharged by the diversion exhaust pipe to heat and dry the upper half of the cold crucible wall. Specifically, as Figure 4a and Figure 4b shown, the second partition 220 of the heating tube in this embodiment consists of a main heating area 221 and a secondary heating area 222. The heights of the secondary heating areas are the same and the sum of their heights is not greater than one-third of the height of the second partition 220 of the heating tube; the main and secondary heating areas are designed to be located in the second partition 220 of the heating tube, effectively utilizing the characteristic that hot air has a small density and automatically flows upward to transfer the heat to the first partition 210; the diversion exhaust pipe in the first partition 210 can heat the upper half of the cold crucible wall by discharging hot air. Specifically, in this step, the position of the inductive coil is adjusted so that it heats the main heating area 221 of the metal heating tube. With reference to a heating power of 10 kW, the cold crucible wall is dried. During the process, the temperature of the main heating area 221 rises, and the temperature of the secondary heating area 222 also rises and is slightly lower than that of the main heating area 221 numerically. On the one hand, through convective heat transfer outside the metal heating tube, the heat is conducted from the metal heating tube to the lower half of the cold crucible wall to dry it; on the other hand, the cold air inside the metal heating tube is heated, its density decreases and it rises and is discharged from the diversion exhaust pipe, and the hot air flows to the upper half of the cold crucible wall surface, and the whole cold crucible wall is evenly heated for the drying process.

[0074] Further, the inductive coil heating system includes a multi-turn inductive coil. As Figure 5 shown, the inductive coil is in a spiral shape. The number of turns N2 of the inductive coil satisfies 3 ≤ N2 ≤ 8, the pitch d satisfies 1 cm ≤ d ≤ 3 cm, the diameter D and the outer diameter g of the cold crucible satisfy D ≥ 1.1g, and the height of the multi-turn inductive coil is the same as the height of the electromagnetic main heating area. It should be understood that in other embodiments of the present invention, the number of turns N2 of the inductive coil can be 3 or 8 or between 3 and 8, and the pitch d can be 1 cm or 3 cm or between 1 cm and 3 cm.

[0075] The multi-turn inductive coil can be energized through a power cabinet, and the formed alternating magnetic field can heat the electromagnetic main heating area 221 and the electromagnetic secondary heating area 222. The heating power P satisfies P ≥ 3 kW. Limiting the parameters of the inductive coil can meet the test requirements while also meeting the needs of preparing the cold crucible wall.

[0076] The above drying process can be adjusted manually according to the drying situation or achieved through automatic control, including but not limited to the following methods: real-time monitoring of the conductivity between the inner and outer wall surfaces at different positions of the cold crucible wall, using the conductivity value to reflect the drying degree of the cold crucible wall surface, and manually operating or automatically adjusting the electric heating power or heating position of the metal heating tube through a control program (the heating position includes but is not limited to the main heating zone 221) to achieve an automated drying process and obtain a more uniform drying effect.

[0077] Further, after applying the paste mixture to the gap between adjacent cold crucible cooling tubes to form the cold crucible wall, it further includes: evenly spraying water droplets on the surface of the cold crucible wall and smearing the surface to make it evenly smooth.

[0078] Further, when using an inductive coil heating system to heat the metal heating tube, it further includes the following two steps: continuously drying the cold crucible wall for 6 - 12 h, and after the surface of the cold crucible wall is dry, evenly applying resin and winding insulating cloth around the surface of the cold crucible wall. The resin is a mixture of polyamide resin and epoxy resin in a volume ratio of 1:1; continuing to dry the cold crucible wall for 1 - 2 h to complete the preparation of the cold crucible wall.

[0079] It should be noted that for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that this application is not limited by the described action sequence, because according to this application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0080] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0081] In summary, from the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0082] 1. The present invention proposes to select the composition of the molten material powder used to prepare the cold crucible wall of the molten material according to the powder of the molten material to be measured used in the experiment, and mix them for preparing the cold crucible wall. This method can greatly reduce the influence on the experiment caused by partial melting of the cold crucible wall, and has advantages such as low economic cost, simple and convenient operation, and high reliability compared with the traditional method for preparing the cold crucible wall.

[0083] 2. The present invention proposes to select the components with melting points higher than 2400 °C in the powder of the melt material to be measured to prepare the cold crucible wall, and proportion the components of the melt material powder according to the test type. While improving the reliability of the cold crucible wall, the material composition ratio of the prepared cold crucible wall is close to that of the melt material powder to be measured, reducing the influence of the partially melted crucible wall on the melt material composition during the test and improving the accuracy of the test results.

[0084] 3. The present invention designs a metal heating tube that can be heated by the inductance coil system of the high-temperature melt measuring device. The metal heating tube is provided with a diversion exhaust pipe and a heating area, which can make the cold crucible wall receive heat efficiently and evenly, improving the drying rate while preventing cracking during the drying process.

[0085] 4. By designing the number and radius of the cold crucible cooling tubes, the wall thickness and outer diameter of the metal heating tube, and the number of turns, pitch, diameter and height of the inductance coil, the present invention can ensure that the cold crucible wall is evenly dried for high-temperature melting tests.

[0086] 5. The method for preparing the cold crucible wall proposed by the present invention utilizes the original equipment and instruments of the high-temperature melt measuring device, such as inductance coils, heating power supplies, cold crucible cooling tubes, etc., greatly reducing the equipment and time costs.

[0087] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the element.

[0088] It should be noted that in the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

Claims

1. A method for preparing a molten cold crucible wall, characterized in that: include: Determine the melt cold crucible to contain the powder of the melt material to be tested in the test; Selecting the composition of the molten material powder used to prepare the molten cold crucible wall according to the composition of the molten material powder to be tested; preparing a paste mixture using the melt material powder; Applying the paste mixture to the gap between adjacent cold crucible cooling tubes to form a cold crucible wall; Fixing the heating tube inside the cold crucible wall; The heating tube is heated to achieve drying of the cold crucible wall.

2. The method according to claim 1, characterized in that The components of the molten material powder are components with a melting point higher than 2400° C. in the molten material powder to be tested, and the components of the molten material powder include one or more of zirconium oxide, uranium oxide, chromium oxide and magnesium oxide.

3. The method according to claim 2, characterized in that In the melt density inversion oxide layer test, the selected melt material powder comprises uranium oxide and zirconium oxide, and the ratio of the uranium oxide to the zirconium oxide is (73±5):(22±5).

4. The method according to claim 2, characterized in that: In the simulation test of the final composition of the molten oxide phase, the selected components of the molten material powder include uranium oxide, zirconium oxide and chromium oxide, and the ratio of the uranium oxide, the zirconium oxide and the chromium oxide is (54±5):(22±5):(10±5).

5. The method according to any one of claims 1 to 4, characterized in that: The method of preparing a paste mixture by using the molten material powder comprises: mixing the molten material powder, a sodium silicate aqueous solution and a silica sol to form a paste mixture.

6. The method according to claim 5, characterized in that The molten material powder, sodium silicate aqueous solution and silica sol are mixed to form a paste mixture, including: mixing the molten material powder, sodium silicate aqueous solution and silica sol in a volume ratio of (4±1):(1±0.1):(1±0.1) to form a paste mixture.

7. The method according to claim 1, characterized in that The cold crucible cooling tubes are arranged in a circular array, the radius R of the cold crucible cooling tubes satisfies 1cm≤R≤2.5cm, the thickness U1 satisfies 1mm≤U1≤2mm, the number N1 of the cold crucible cooling tubes satisfies 12≤N1≤48; and the distance M between two adjacent cold crucible cooling tubes satisfies 0.5cm≤M≤3cm.

8. The method according to claim 1, characterized in that The heating pipe is a metal heating pipe, which is composed of a hanging ring, a heating pipe and a diversion exhaust pipe. The heating pipe includes a first partition and a second partition, and the diversion exhaust pipe is located in the first partition.

9. The method according to claim 8, characterized in that The metal heating tube has the same height as the cold crucible cooling tube, and the tube wall thickness U2 of the metal heating tube satisfies 2mm≤U2≤4mm, and the outer diameter l of the metal heating tube and the inner diameter f of the cold crucible satisfy 0.3f≤l≤0.5f.

10. The method according to claim 8, characterized in that The first partition has the same height as the second partition.

11. The method according to claim 8, characterized in that The guide exhaust pipes are arranged downward at an angle of 45° to the horizontal direction and are arranged in a circular array.

12. The method according to any one of claims 8 to 11, characterized in that The heating tube is heated to achieve drying of the cold crucible wall, comprising: heating the metal heating tube by using an induction coil heating system.

13. The method according to any one of claim 12, characterized in that: The induction coil heating system is used to heat the second partition of the heating tube to achieve heating and drying of the lower half of the crucible wall, and to transfer heat to the first partition, and the hot air is discharged from the guide exhaust pipe to heat and dry the upper half of the cold crucible wall.

14. The method according to claim 12, characterized in that The inductor coil heating system comprises a multi-turn inductor coil, the inductor coil is in a spiral shape, the number of turns N2 of the inductor coil satisfies 3≤N2≤8, the pitch d satisfies 1cm≤d≤3cm, and the diameter D and the outer diameter g of the cold crucible satisfy D≥1.1g.

15. The method according to claim 1, characterized in that After applying the paste mixture to the gap between adjacent cold crucible cooling tubes to form the cold crucible wall, the method further comprises: Water droplets are evenly sprayed on the surface of the cold crucible wall, and the surface is smeared to make it even and smooth.

16. The method according to claim 12, characterized in that The metal heating tube is heated by an induction coil heating system, and further comprises: The cold crucible wall is continuously dried for 6-12 hours. After the surface of the cold crucible wall is dried, resin is evenly applied and insulating cloth is wrapped around the surface of the cold crucible wall; The cold crucible wall is further dried for 1-2 hours to complete the preparation of the cold crucible wall.

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