Molybdenum-lined crucible
The crucible design with a molybdenum-lined graphite housing and gas escape mechanism addresses the stability and gas flow issues of conventional materials, enabling stable and efficient sintering of uranium oxide gel particles.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- X ENERGY LLC
- Filing Date
- 2024-03-20
- Publication Date
- 2026-06-23
AI Technical Summary
Conventional crucibles made of graphite, tungsten, or tantalum are not chemically stable with uranium oxide particles, leading to unwanted reactions and leakage during the sintering of uranium oxide gel particles, and they do not allow sufficient gas flow to exhaust reactive processing gases.
A crucible design featuring a graphite housing lined with a chemically inert metal sleeve, such as molybdenum, and a detachable inner and outer cap system that allows gas escape, along with a compressible carbon fiber felt to manage thermal expansion, ensuring the crucible remains stable and allows gas flow.
The crucible prevents unwanted reactions between metal oxide gel particles and graphite, maintains structural integrity under high temperatures, and enables efficient gas exhaust, ensuring stable sintering of uranium-based ceramic fuel kernels.
Smart Images
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Abstract
Description
Technical Field
[0001] The various embodiments disclosed herein generally relate to reactors for sintering metal oxide gel particles, such as crucibles for sintering metal oxide gel particles.
Background Art
[0002] During the sintering of uranium oxide gel particles for the production of uranium oxide, uranium carbide, and / or uranium oxycarbide fuel kernels, it is important that the crucible be chemically stable at temperatures up to 1800° C. with uranium oxides, carbides, and oxycarbides. Conventionally, for the sintering of uranium oxide gel particles, crucibles made of graphite, tungsten, or tantalum have been used regardless of the presence of a carbon source. However, these materials may not be chemically stable with respect to uranium oxide particles. For example, graphite reacts with uranium dioxide particles to form a layer of UC2 on the particle surface. This reaction may also cause uranium to leach into the inner surface of the graphite crucible.
[0003] Molybdenum metal has the highest chemical stability with respect to uranium oxides and carbides at extreme temperatures and is an optimal material for the production of uranium-based ceramic fuel kernels. However, molybdenum is heavy, easily carbonizes in the presence of graphite, and often forms strong welds when in contact with graphite at temperatures above 1700° C. Further, the crucible needs to allow sufficient gas flow to exhaust the reactive processing gases generated during the sintering process from the crucible while preventing the kernels from leaking out of the crucible.
[0004] In view of the above, a crucible improved for the reaction of metal oxide gel particles (including uranium oxide gel particles) is desirable. The crucible needs to be lightweight, easily filled, chemically and thermally stable with respect to metal oxide gel particles, and allow sufficient gas flow.
Summary of the Invention
[0005] In light of the need for improvements to crucibles for sintering metal oxide gel particles, an overview of various embodiments is provided below. The following summary may contain some simplifications and omissions, which are intended to highlight and introduce some aspects of the various embodiments but are not intended to limit the scope of the invention. A detailed description of specific embodiments sufficient for those skilled in the art to fabricate and use the concepts disclosed herein will follow later.
[0006] The embodiments disclosed herein relate to a crucible for forming ceramic particles from metal oxide gel particles, and include a cylindrical housing made of graphite having a seat on its inner surface near at least one open end, and a sleeve lining the inner surface of the cylindrical housing, having at least one open end, and made of a metal that is chemically inert to the metal oxide gel particles. An outer cap made of graphite detachably covers at least one open end of the cylindrical housing. An inner cap made of a chemically inert metal is configured to fit into the seat on the inner surface of the cylindrical housing. The outer cap is configured to press the inner cap against the seat and into contact with the open end of the sleeve.
[0007] The inner and outer caps may be configured to allow gas to escape from the crucible. The inner cap is configured to allow gas to pass through, and the outer cap has an axial through-hole, allowing gas that has passed through the inner cap to escape through the axial through-hole of the outer cap. In various embodiments, the inner cap includes at least one through-hole, the width of which is less than 50% of the average particle size of the metal oxide gel particle aggregate in the crucible. The inner cap includes at least one through-slit, the width of which is less than 50% of the average particle size of the metal oxide gel particles.
[0008] In various embodiments, the crucible also includes a compressible carbon fiber felt, which is compressed into the inner cap by the outer cap.
[0009] The crucible includes a graphite ring having an outer seat, the outer seat configured to engage with the edge of the inner cap, and the graphite ring configured to be pressed against the edge of the inner cap by the outer cap.
[0010] The crucible may include: a graphite ring having an outer seat, configured to engage with the edge of an inner cap; and a ring of compressible carbon fiber felt, configured to be compressed into the graphite ring by the outer cap.
[0011] In various embodiments, the crucible is configured to rotate about its axis, and the crucible further comprises a rotatable drive shaft configured to engage with an outer cap. The rotatable drive shaft includes a polygonal end, and the outer cap includes a polygonal socket configured to engage with the polygonal end of the rotatable drive shaft. The rotatable drive shaft includes an axial through hole, and the outer cap includes a through hole, and the through holes in the rotatable drive shaft and the outer cap are configured to provide a path for gas to escape from inside the crucible.
[0012] In various embodiments, the crucible is configured to rotate about its axis, and the crucible further includes a rotatable drive shaft configured to engage with an outer cap. The rotatable drive shaft includes a polygonal end and a hemispherical ball extending from the polygonal end of the rotatable drive shaft. The outer cap includes a socket configured to receive the polygonal end of the rotatable drive shaft, and the socket includes an inner hemispherical socket configured to engage with the hemispherical ball of the rotatable drive shaft, and an outer polygonal socket configured to engage with the polygonal end of the rotatable drive shaft. The rotatable drive shaft includes an axial through hole, and the outer cap includes a through hole, and the through hole of the rotatable drive shaft and the through hole of the outer cap are configured to provide a path for gas to escape from inside the crucible.
[0013] Various embodiments disclosed herein relate to a crucible for forming ceramic uranium-containing particles from uranium oxide gel particles, and include a cylindrical housing formed of graphite having at least one open end, an inner surface, and a seat on the inner surface near at least one end, and a sleeve lining the inner surface of the cylindrical housing having at least one open end. An outer cap detachably covers at least one open end of the cylindrical housing. An inner cap may be configured to fit into the seat on the inner surface of the cylindrical housing. Alternatively, the outer cap may be configured to press the inner cap against the seat and abut the open end of the sleeve. The sleeve and inner cap may be formed of molybdenum. The sleeve and inner cap may be formed of a molybdenum alloy containing 0.5% titanium, 0.08% zirconium, 0.02% carbon, or a mixture thereof. [Brief explanation of the drawing]
[0014] Refer to the attached drawings for a better understanding of the various embodiments. [Figure 1] Figure 1 shows a crucible for forming ceramic particles from metal oxide gel particles, with one end sealed by an outer cap and the other end open. [Figure 2A] Figure 2A shows a cross-section of the crucible in Figure 1, viewed from the direction of arrow A in Figure 1. [Figure 2B] Figure 2B shows a detailed cross-section of Figure 2A, illustrating the outer and inner caps. [Figure 3] Figure 3 shows the cylindrical shell used in the crucible shown in Figure 1. [Figure 4A] Figure 4A shows a cross-section of the cylindrical shell in Figure 3, viewed from the direction of arrow D in Figure 3. [Figure 4B] Figure 4B shows a detailed view of the cross-section in Figure 4A. [Figure 5] Figure 5 shows the sleeve used in the crucible shown in Figure 1. [Figure 6] Figure 6 shows a cross-section of the sleeve in Figure 5, viewed from the direction of arrow C in Figure 5. [Figure 7]Figures 7A and 7B show an outer cap used in the crucible of FIG. 1. [Figure 8] Figures 8A and 8B show a ring of compressible carbon fiber felt used in the crucible of FIG. 1. [Figure 9] Figures 9A and 9B show a graphite ring used in the crucible of FIG. 1. [Figure 10] Figures 10A to 10D show an inner cap of the first embodiment used in the crucible of FIG. 1. [Figure 11] Figures 11A and 11B show an inner cap of the second embodiment used in the crucible of FIG. 1. [Figure 12] Figures 12A to 12C show an inner cap of the third embodiment used in the crucible of FIG. 1. [Figure 13] FIG. 13 shows a first part of a rotatable drive shaft. [Figure 14] FIG. 14 shows a first part of a rotatable drive shaft. [Figure 15] FIG. 15 shows a second part of a rotatable drive shaft. [Figure 16] FIG. 16 shows a second part of a rotatable drive shaft. [Figure 17] FIG. 17 shows the engagement of the second part of the rotatable drive shaft of FIG. 15 with the outer cap of FIG. 7B.
BEST MODE FOR CARRYING OUT THE INVENTION
[0015] Referring to the drawings, like numbers refer to like components or steps, and broad aspects of various embodiments are disclosed.
[0016] FIG. 1 shows a crucible 1 according to the present disclosure, including a cylindrical housing 2 formed of graphite. The housing is covered at its open end by a detachable outer cap 3 formed of graphite. The opposite end may also be open or may be closed. If the opposite end is open, it may be covered by a second detachable cap 3 (not shown in FIG. 1). The outer cap 3 is threaded into a thread 5 as shown in FIG. 2A.
[0017] Figure 2A shows a cross section of the crucible 1 of FIG. 1. In this cross section, each end of the cylindrical housing 2 is open. The seat portion 4 is machined on the inner surface of each end of the cylindrical housing 2. The spiral thread 5 is machined on the inner surface of each end of the cylindrical housing 2, and the spiral thread 5 is located between the seat portion 4 and the edge of the open end of the cylindrical housing 2. The socket 9 is machined on the outer cap 3. The socket 9 is intended to engage with the rotating shaft in the manner described later. The inner surface of the cylindrical housing is lined with a metal sleeve 11.
[0018] The choice of the metal of the sleeve 11 depends on the properties of the metal oxide gel particles sintered in the crucible 1, and the metal of the sleeve 11 must be chemically inert to the metal oxide gel particles to be sintered. In various embodiments, the metal oxide gel particles may be uranyl oxide gel particles. In that case, the metal of the sleeve 11 may be molybdenum, tungsten, or an alloy thereof. Suitable molybdenum alloys include 0.5% titanium, 0.08% zirconium, 0.02% carbon, or a mixture thereof. The TZM alloy of 0.5% titanium, 0.08% zirconium, 0.02% carbon, and the balance molybdenum may be used.
[0019] The thickness of the sleeve 11 may be 0.5 - 5 mm, 1 - 4 mm, or 2 - 3 mm. The sleeve 11 may be machined from a solid rod of a desired metal, such as molybdenum, tungsten, or TZM alloy. A sheet of the desired metal may be formed into a cylinder, and the opposing edges of the sheet may be caulked to form the cylindrical sleeve 11. A metal foil may be used to line the inner surface of the housing 2 with a layer of the desired metal. The inner surface of the housing 2 may be coated with tungsten or molybdenum by chemical vapor deposition (CVD) using a compound known as WF6, Mo(CO)6, or other metal precursors. In the present disclosure, the term "sleeve" is construed to include cylindrical sheets or foils, as well as CVD coating layers.
[0020] Figure 2B is a detail of one end of the cross-section of crucible 1 in Figure 2A. As shown in Figure 2B, the sleeve 11 lines the inner surface of the cylindrical housing 2 of the crucible 1. The inner cap 6 is formed from two metal plates, an outer plate 6a and an inner plate 6b. The edge of the inner cap 6 is located within the seat 4 of the housing 2. The graphite ring 7 includes the seat 13 and engages with the edge of the inner cap 6. The graphite ring 7 presses the inner cap 6 into the seat 4 and brings the inner cap 6 into contact with the edge of the sleeve 11. A ring or disc 8 of compressible carbon fiber felt or graphite mesh is positioned in contact with the graphite ring 7. Finally, the outer cap 3 is screwed onto the open end of the housing 2, and the threaded outer surface 10 of the outer cap 3 engages with the helical threads 5 on the inner surface of the cylindrical housing 2. The outer cap 3 presses the carbon fiber felt ring or disc 8, the graphite ring 7, and the inner cap 6 against the end of the sleeve 11. When metal oxide gel particles are placed in crucible 1 and the open end of housing 2 is sealed with outer cap 3, the metal oxide gel particles come into contact only with the metal sleeve 11 and metal inner cap 6, and not with the graphite housing 2 or graphite outer cap 3. This prevents unwanted reactions between the metal oxide gel particles and graphite.
[0021] The carbon fiber felt ring or disc 8 is present to prevent damage to the cylindrical housing 2 or outer cap 3 due to thermal expansion of the metal sleeve 11. Without the carbon fiber felt ring or disc 8, the sleeve 11 within the housing 2 cannot expand relative to the cap 3, potentially causing cracks or other damage to the housing 2 or cap 3 due to the thermal expansion of the sleeve 11. However, with the carbon fiber felt ring or disc 8 present, as the sleeve 11 expands longitudinally within the housing 2 toward the cap 3, the carbon fiber felt ring or disc 8 can be compressed. This relieves the stress on the housing 2 and cap 3 caused by the expansion of the sleeve 11.
[0022] Figure 3 shows a graphite cylindrical housing 2 used in the crucible 1 according to this disclosure. The graphite cylindrical housing 2 has at least one open end (not shown in Figure 3). The graphite cylindrical housing 2 may have one end open and the other end closed. The graphite cylindrical housing 2 may have both ends open.
[0023] Figure 4A shows a cross-section of the graphite cylindrical housing 2, the cross-section being along a plane containing the axis of the housing 2 indicated by arrow D in Figure 3. The embodiment of the graphite cylindrical housing 2 shown in Figure 4A has open ends at both ends. Seats 4 are machined into the inner surface of each end of the cylindrical housing 2. Spiral threads 5 are machined into the inner surface of each end of the cylindrical housing 2, and the spiral threads 5 are located between the seat 4 and the edge of the open end of the cylindrical housing 2. Figure 4B is a detailed view of the open end of the graphite cylindrical housing 2, including the seat 4 and the threads 5.
[0024] Figure 5 shows a cylindrical sleeve 11, the outer diameter of which is sized so that the sleeve 11 can be inserted longitudinally into the housing 2 in Figure 3. Figure 6 shows a cross-section of the cylindrical sleeve 11, the cross-section is along the plane containing the axis of the sleeve 11 indicated by arrow C in Figure 5. The sleeve 11 has at least one open end. The sleeve 11 may have one open end at one end and the opposite end closed. The sleeve 11 may also have one open end at each end, as shown in Figure 6. If the sleeve 11 has only one open end, it should be inserted longitudinally into the housing 2 in Figure 3 so that the open end of the sleeve 11 is located at the open end of the housing 2.
[0025] Figures 7A and 7B show the outer cap 3 used in the crucible 1 of Figure 1. As shown in Figure 7A, the outer cap 3 has a helical male thread 10 on its outer surface. Figure 7B is a cross-section of the outer cap 3 viewed from the direction of arrow F in Figure 7A. As shown in Figure 7B, an axial socket 9 penetrates the center of the outer cap 3. Polygonal outer sockets 9a, such as triangles, squares, pentagons, and hexagons, are formed on the outer surface of the outer cap 3. Holes 9c, such as cylindrical or polygonal, are formed on the inner surface of the outer cap 3. The holes 9c and the outer sockets 9a are in fluidic communication, either directly or via an inner socket portion 9b. If an inner socket portion 9b is present, it has a hemispherical surface that connects the holes 9c and the outer socket portion 9a.
[0026] Figures 8A and 8B show a ring or disc 8 of compressible carbon fiber felt or graphite mesh used in crucible 1 of Figure 1. Figure 8B is a cross-section of the felt or mesh 8 viewed from the direction of arrow H in Figure 8A. As shown in Figure 8B, the ring or disc 8 of felt or mesh may be a ring having through holes 12. In various embodiments, the ring or disc 8 of felt or mesh may be a continuous disc without through holes 12, as long as it is permeable to gas.
[0027] Figures 9A and 9B show the graphite ring 7 used in the crucible 1 of Figure 1. Figure 9B is a cross-section of the graphite ring 7 viewed from the direction of arrow G in Figure 9A. As shown in Figure 9B, the graphite ring 7 has an inner seat 13 and a through hole 14.
[0028] Figures 10A and 10B show the inner cap 6 used in the crucible 1 of Figure 1. Figure 10B is a cross-section of the inner cap 6 viewed from the direction of arrow J in Figure 10A. As shown in Figures 10A and 10B, the inner cap 6 is formed from two metal plates, an outer plate 6a and an inner plate 6b. As shown in Figure 10C, the outer plate 6a has two large holes 15 formed symmetrically on either side of its geometric center. Multiple small gas-permeable openings 16 penetrate the plate 6a, and the openings 16 may be located at the vertices of a regular polygon with even-numbered sides. As shown in Figure 10C, the openings 16 may also be located at the vertices of a square. Another opening 16 may be located at the geometric center of the outer plate 6a. The structure of the inner plate 6b is identical to that of the outer plate 6a. As shown in Figure 10D, the outer plate 6a and the inner plate 6b are assembled so that the openings 16 of the outer plate 6a and the openings 16 of the inner plate 6b coincide. The outer plate 6a and inner plate 6b are assembled such that the large hole 15 in the outer plate 6a is offset from the large hole 15 in the inner plate 6b. When the openings 16 are located at the vertices of a square, the large hole 15 in the outer plate 6a is offset by 180 degrees from the large hole 15 in the inner plate 6b. When the openings 16 are located at the vertices of a regular hexagon, for example, the large hole 15 in the outer plate 6a may be offset by 120 degrees from the large hole 15 in the inner plate 6b, so that the openings 16 of the outer plate 6a and the inner plate 6b coincide. The outer plate 6a and inner plate 6b are each 0.5 mm to 2.5 mm thick, or approximately 1.25 mm to 1.75 mm thick. The outer plate 6a and inner plate 6b are made from molybdenum, tungsten, or alloys thereof. The outer plate 6a and inner plate 6b may also be made from TZM alloy. In various embodiments, the opening 16 is smaller than the average particle size of the metal oxide gel particles being sintered, or less than 67% or 50% of the average particle size of the metal oxide gel particles. This allows vapor to escape from the crucible while preventing particles from leaking out of the sealed crucible.
[0029] Returning to Figure 2B, each open end of the housing 2 is closed by bringing the inner surface of the inner cap 6 into contact with the edge of the sleeve 11 within the seat 4 on the inner surface of the cylindrical housing 2. The graphite ring 7 is positioned on the outer surface of the inner cap 6, with the edge of the inner cap 6 fitting into the seat 13 (see Figure 9B) of the graphite ring 7. A ring or disc 8 of compressible carbon fiber felt or graphite mesh is positioned in contact with the outer surface of the graphite ring 6. The threaded outer surface 10 of the outer cap 3 is screwed onto the end of the cylindrical housing 2, and the threaded outer surface 10 engages with the helical threads 5 on the inner surface of the cylindrical housing 2. The outer cap 3 is screwed onto the housing 2, compressing the ring or disc 8 into the graphite ring 7 and holding the inner cap 3 in the cylindrical sleeve 11. If the cylindrical housing 2 and sleeve 11 each have only one open end, the metal oxide gel particles can be filled into the sleeve 11, and then the open ends of the cylindrical housing 2 and sleeve 11 can be closed as shown in Figure 2B. If the cylindrical housing 2 and sleeve 11 each have open ends at both ends, one open end of the cylindrical housing 2 and sleeve 11 can be closed as shown in Figure 2B. Then, the metal oxide gel particles can be filled into the sleeve 11, and the other open end can be closed. When both open ends of the cylindrical housing 2 and sleeve 11 are closed, the metal oxide gel particles will only be in contact with the metal or metal alloy surfaces of the sleeve 11 and inner cap 6, and will not be in contact with the graphite components of the crucible 1.
[0030] Figures 11A and 11B show another embodiment of the inner cap 6 used in the crucible 1 of Figure 1. As shown in Figure 11A, the inner cap 6 is formed from a single metal plate 17. The plate 17 has several small gas-permeable openings 18 that penetrate it, and as shown in Figure 11A, the openings 18 may be arranged on lines radiating from the geometric center of the plate 17. Alternatively, the openings 18 may be arranged on several concentric circles, or they may be randomly placed on the plate 17. The plate 17 has a thickness of 1.5 mm to 4 mm, about 2.5 mm to 3.5 mm, or about 3 mm. The plate 17 is made from molybdenum, tungsten, or TZM alloy. In various embodiments, the openings 18 are smaller than the average particle size of the metal oxide gel particles to be sintered, or less than 67% or less than 50% of the average particle size of the metal oxide gel particles, or have a diameter of 0.5 mm to 0.15 mm. This prevents particles from leaking out of the sealed crucible while allowing vapor to escape.
[0031] Figures 12A and 12B show another embodiment of the inner cap 6 used in the crucible 1 of Figure 1. As shown in Figure 12A, the inner cap 6 is formed from a single metal plate 19. The plate 17 has several narrow gas-permeable slits 20 that penetrate through it, and the slits 20 may be arranged parallel to the plate 19 as shown in Figure 12A. The plate 19 has a thickness of 1.5 mm to 4 mm, about 2.5 mm to 3.5 mm, or about 3 mm. The plate 19 is made from molybdenum, tungsten, or TZM alloy. In various embodiments, the slits 20 are narrower than the average particle size of the metal oxide gel particles being sintered, or less than 67% or less than 50% of the average particle size of the metal oxide gel particles, or 0.5 mm to 0.15 mm in width. This allows vapor to escape from the crucible while preventing particles from leaking out of the sealed crucible.
[0032] Once the crucible is filled with metal oxide gel particles, it is heated to an effective sintering temperature, and the metal oxide gel particles are converted into ceramic particles. The inner sleeve 11 and inner cap 6 prevent the metal oxide gel particles and / or ceramic particles from coming into contact with the graphite housing or outer cap 3. Sleeves 11 and inner cap 6 made of molybdenum, tungsten, or TZM alloy are stable with respect to the metal oxide gel particles and / or ceramic particles and do not react with the metal oxide gel at temperatures up to 2000°C. Without the alloy sleeves 11 and inner cap 6, the graphite housing would react with the metal oxide gel, causing the metal oxide gel particles to carbonize.
[0033] In various embodiments, the crucible 1 may have its longitudinal axis oriented horizontally, as shown in Figure 1. The crucible rotates around its longitudinal axis, thereby mixing the metal oxide gel particles within the cylindrical sleeve 11 and ensuring uniform heating as the metal oxide gel particles are converted into solid ceramic particles. The cylindrical housing may be supported by a rotating bearing (not shown) or a similar support that allows rotational movement of the housing 2. The rotation of the crucible 1 is driven by a rotating shaft driven by a motor (not shown), which engages with the outer cap 9 of the crucible 1.
[0034] Figures 13 and 14 show the first part 21 of a rotating shaft made of tungsten, molybdenum, or TMZ alloy. The first part 21 includes a cylindrical shaft 24 having an axial through hole 24a. The first end of the shaft 24 includes an expanding socket 22, on which an internal thread 23 is formed. The second end of the shaft 24 includes a socket 26, on which an internal thread 25 is formed. The internal thread 25 of the socket 26 is configured to engage with the threaded end of a motor-driven shaft. The internal thread 23 of the socket 22 is configured to engage with the second part 27 of the rotating shaft shown in Figure 15.
[0035] Figures 15 and 16 show a second part 27 of a rotating shaft made of graphite, tungsten, molybdenum, or TMZ alloy. The second part 27 includes a shaft 28. A male thread 32 is formed on the outer surface of the first end of the shaft 28. A polygonal projection 29 is formed on the second end of the shaft 28, which may be milled on the outer surface of the shaft 28. As shown in Figure 15, the polygonal projection 29 may be square. Alternatively, the polygonal projection 29 may be triangular, pentagonal, or hexagonal. A hemispherical projection 30 is also formed on the second end of the shaft 28, which may be milled on the outer surface of the polygonal projection 29. The male thread 32 is configured to engage with a female thread 23 of a socket 22 of the first part 21 of the rotating shaft. The projections 29 and 30 of the second part 27 of the rotating shaft are configured to engage with the outer cap 3 of the crucible 1 shown in Figure 17. The second part 27 of the rotating shaft has an axial through hole 31. When the male screw 32 engages with the female screw 23 of the socket 22, the axial through hole 31 and 24a are in fluid communication.
[0036] If necessary, the first part 21 and the second part 27 of the rotating shaft may be integrally molded and may be made of graphite, tungsten, molybdenum, or TMZ alloy.
[0037] Referring to Figure 17, the axial socket 9 penetrates the center of the outer cap 3 of the crucible 1. A polygonal outer socket 9a is formed on the outer surface of the outer cap 3. The polygonal outer socket 9a is configured to engage with the polygonal projection 29 of the second part 27 of the rotating shaft. The inner socket portion 9b has a hemispherical surface and is configured to engage with the hemispherical projection 30 of the second part 27 of the rotating shaft. A hole 9c is formed on the inner surface of the outer cap 3. The hole 9c and the axial through hole 31 of the second part 27 of the rotating shaft are in fluid communication, providing a path for gas to escape from the crucible 1. As the rotating shaft rotates, the polygonal projection 29 transmits torque to the polygonal outer socket 9a of the outer cap 3, causing the crucible 1 to rotate around its longitudinal axis.
[0038] While various embodiments are described in detail in particular aspects of specific embodiments, it should be understood that other embodiments are also possible and their details can be modified in various obvious ways. Modifications and alterations are possible within the spirit and scope of the invention, as will be readily apparent to those skilled in the art. Accordingly, the foregoing disclosures, descriptions, and drawings are for illustrative purposes only and do not limit the invention in any way, and the invention is defined solely by the claims.
Claims
1. A crucible for forming ceramic particles from metal oxide gel particles, A cylindrical housing made of graphite having a seat on at least one open end, an inner surface, and an inner surface near at least one open end, A sleeve lining the inner surface of the cylindrical housing, having at least one open end, and formed of a metal that is chemically inert to metal oxide gel particles, A graphite outer cap that detachably covers at least one open end of the cylindrical housing, An inner cap formed from a chemically inert metal, Equipped with, The inner cap is configured to fit into a seat on the inner surface of the cylindrical housing. The outer cap is configured to press the inner cap against the open end of the sleeve into the seat portion. Crucible.
2. A crucible according to claim 1, wherein the inner cap and the outer cap are configured to allow gas to escape from inside the crucible.
3. The crucible according to claim 2, The inner cap is configured to allow gas to pass through its interior. The outer cap has an axial through hole. Crucible.
4. The crucible according to claim 3, The inner cap is provided with at least one through hole, and the at least one hole has an average particle size of less than 50% of the metal oxide gel particles. Crucible.
5. The crucible according to claim 3, The inner cap is provided with at least one through-slit, and the width of the at least one slit is less than 50% of the average particle size of the metal oxide gel particles. Crucible.
6. A crucible according to claim 1, further comprising a compressible carbon fiber felt, wherein the compressible carbon fiber felt is configured to be compressed by the outer cap into the inner cap.
7. A crucible according to claim 1, further comprising a graphite ring having an outer seat, wherein the outer seat is configured to engage with the edge of the inner cap, and the graphite ring is configured to be pressed against the edge of the inner cap by the outer cap.
8. A crucible according to claim 7, further comprising a ring of compressible carbon fiber felt, wherein the ring of compressible carbon fiber felt is configured to be compressed into the graphite ring by the outer cap.
9. A crucible according to claim 1, The crucible is configured to rotate around its axis, The crucible further comprises a rotatable drive shaft, The rotatable drive shaft is configured to engage with the outer cap. Crucible.
10. The crucible according to claim 9, The rotatable drive shaft is provided with polygonal ends, The outer cap comprises a polygonal socket configured to engage with the polygonal end of the rotatable drive shaft. Crucible.
11. A crucible according to claim 10, The rotatable drive shaft has a through hole inside it, The outer cap has a through hole, The through-holes in the rotatable drive shaft and the through-holes in the outer cap are configured to provide a path for gas to escape from inside the crucible. Crucible.
12. The crucible according to claim 9, The rotatable drive shaft comprises a polygonal end and a hemispherical ball extending from the polygonal end of the rotatable drive shaft, The outer cap comprises a socket configured to receive the end of the rotatable drive shaft, The aforementioned socket is An inner hemispherical socket configured to engage with a hemispherical ball of the rotatable drive shaft, An outer polygonal socket configured to engage with the polygonal end of the rotatable drive shaft. A crucible equipped with a crucible.
13. The crucible according to claim 12, The rotatable drive shaft has a through hole inside it, The outer cap has a through hole, The through-holes in the rotatable drive shaft and the through-holes in the outer cap are configured to provide a path for gas to escape from inside the crucible. Crucible.
14. A crucible for forming ceramic uranium-containing particles from uranium oxide gel particles, A cylindrical housing made of graphite having a seat on at least one open end, an inner surface, and an inner surface near at least one open end, A sleeve lining the inner surface of the cylindrical housing, having at least one open end, and formed of molybdenum or an alloy thereof, An outer cap that detachably covers at least one open end of the cylindrical housing, An inner cap formed from molybdenum or its alloy, Equipped with, The inner cap is configured to fit into a seat on the inner surface of the cylindrical housing. The outer cap is configured to press the inner cap against the open end of the sleeve into the seat portion. Crucible.
15. A crucible according to claim 14, wherein the sleeve and the inner cap are formed from molybdenum, tungsten, or an alloy thereof.
16. A crucible according to claim 14, wherein the sleeve and the inner cap are formed from a molybdenum alloy containing 0.5% titanium, 0.08% zirconium, 0.02% carbon, or a mixture thereof.