Precious metal high-cleanness smelting composite crucible

Abstract

The utility model relates to a precious metal high-cleanliness smelting composite crucible which comprises an oxide body, the oxide body comprises a bottom and a side wall which are integrally formed, a graphite outer layer is arranged on the periphery of the side wall in a sleeved mode, the bottom end of the graphite outer layer is flush with the bottom of the oxide body, at least two bosses are arranged at the top end of the graphite outer layer, and the bosses are arranged on the bottom of the oxide body. The boss is inwards buckled at the top end of the side wall of the oxide body, and a filler is filled between the side wall of the oxide body and the graphite outer layer. According to the composite crucible disclosed by the utility model, the graphite outer layer is sleeved on the outer side of the oxide body, so that carbon pollution caused by contact between a noble metal solution and graphite is avoided, and the problem of heating is solved. Meanwhile, the composite structure effectively prevents the crucible opening from cracking during inclined casting, and the service life of the crucible is greatly prolonged. By means of the function, the smelted precious metal welding flux is higher in quality and more stable in performance, the production efficiency is improved, the production cost is reduced, and various different production requirements can be met.

Description

Technical Field

[0001] This utility model relates to the field of precious metal smelting technology, specifically to a high-cleanliness composite crucible for precious metal smelting. Background Technology

[0002] Currently, the main types of crucibles used in precious metal smelting are graphite crucibles, high-purity alumina crucibles, and high-purity zirconia crucibles. Graphite crucibles are made of high-purity graphite, with carbon as the main component. They are chemically stable and have good thermal conductivity, making them the most commonly used crucibles. High-purity alumina crucibles are heat-resistant and chemically stable, but have slightly lower thermal conductivity, making them suitable for smelting precious metal alloys at temperatures below 1700℃. High-purity zirconia crucibles have excellent heat resistance and strong chemical stability, and can be used to smelt precious metal alloys at temperatures up to 2500℃.

[0003] However, these conventional crucibles have a simple structure and various limitations and shortcomings in the use of precious metal solders requiring high cleanliness. For example, graphite crucibles, made of high-purity graphite, are mainly composed of carbon. During high-temperature melting, carbon interacts with precious metals and enters the alloy, introducing carbon contamination and increasing the carbon content. Furthermore, when using graphite crucibles for induction heating, the crucible itself generates heat due to the skin effect. As for high-purity alumina and zirconia crucibles, since high-temperature induction melting relies primarily on the induction heating of the precious metal alloy, the crucible itself does not generate heat. This leads to a large temperature difference between the top and bottom of the molten precious metal, making the crucible prone to cracking due to uneven thermal expansion. This results in a short crucible lifespan and easy loss of precious metals through cracks. Therefore, there is an urgent need to improve the structure of existing crucibles used for precious metal melting. Utility Model Content

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings and defects and propose a composite crucible that combines the advantages of graphite crucibles and oxide crucibles. When matched with a water-cooled induction coil, it can be used to melt precious metal alloys, and is especially suitable for melting precious metal solders with a carbon content of ≤20PPM.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A high-cleanliness composite crucible for smelting precious metals includes an oxide body, the oxide body comprising an integrally formed bottom and sidewalls, a graphite outer layer sleeved around the outer periphery of the sidewalls, the bottom end of the graphite outer layer being flush with the bottom of the oxide body, and at least two protrusions at the top end of the graphite outer layer, the protrusions being inwardly engaged with the top end of the sidewalls of the oxide body, and a filler being filled between the sidewalls of the oxide body and the graphite outer layer.

[0007] This invention utilizes a graphite outer layer surrounding the oxide body. The graphite outer layer heats up under induction heating in a medium-frequency furnace and conducts the heat to the inner oxide body, preventing carbon contamination from contact between the precious metal solution and the graphite. Furthermore, a filler material is placed between the oxide body and the graphite outer layer. This ensures a tight bond between the inner and outer layers and allows for uniform heat transfer to the inner oxide body, enabling rapid heating of the precious metal within the oxide body and shortening melting time. The filler also acts as a buffer, reducing thermal stress between the graphite outer layer and the inner oxide body. This solves the problems of carbon contamination and uneven heating in traditional single-structure crucibles. The bosses on the graphite outer layer provide fixation and help ensure the rigidity of the gating gate, preventing deformation during high-temperature melting and casting.

[0008] Preferably, the filler is an adhesive.

[0009] More preferably, the adhesive is a high-temperature adhesive or a powder mixture of water glass and oxides.

[0010] Preferably, the connection between the bottom and the inner sidewall of the oxide body is rounded. During inclined casting, the rounded corners ensure that the molten metal flows smoothly out of the crucible without remaining at the bottom. This avoids metal waste and reduces the difficulty of subsequent cleaning. Simultaneously, the rounded corners help alleviate thermal stress, allowing the crucible to better withstand the effects of thermal expansion and contraction during high temperatures and cooling, thus extending the crucible's service life.

[0011] Preferably, the fillet radius is 10-30mm, which can withstand higher temperatures and has a longer service life.

[0012] Preferably, the oxide body is an oxide body suitable for precious metal smelting, such as an alumina body, a zirconium oxide body, a magnesium oxide body, or a calcium oxide body.

[0013] Preferably, the sidewall thickness of the oxide body is 10mm-15mm, the bottom thickness is 15mm-20mm, and the thickness of the graphite outer layer is 20mm-30mm; this provides a good match, good heat resistance, and a long service life.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] This invention relates to a composite crucible that, by layering a graphite outer layer around the oxide body, avoids carbon contamination introduced by contact between the precious metal solution and the graphite, while also solving the heating problem. The graphite outer layer generates heat through induction and, thanks to its excellent thermal conductivity, evenly conducts the heat to the inner oxide body, preventing temperature differences. Simultaneously, this composite structure effectively prevents cracking at the crucible opening during tilted casting, significantly extending the crucible's service life. Its effects result in higher quality and more stable performance of the smelted precious metal solder, improving production efficiency, reducing production costs, and adapting to various production needs. It is particularly suitable for smelting precious metal solders requiring a carbon content ≤20ppm. Attached Figure Description

[0016] Figure 1 This is a schematic cross-sectional view of the composite crucible for high-cleanliness smelting of precious metals according to an embodiment of this utility model.

[0017] Figure 2 This is one of the schematic diagrams of the boss structure of the precious metal high-cleanliness smelting composite crucible according to an embodiment of this utility model;

[0018] Figure 3 This is the second schematic diagram of the boss structure of the precious metal high-cleanliness smelting composite crucible according to an embodiment of this utility model;

[0019] Figure 4 This is a schematic diagram of the oxide body structure of a high-cleanliness composite crucible for precious metal smelting according to an embodiment of this utility model. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that the terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] refer to Figure 1-4 This invention provides a high-cleanliness composite crucible for smelting precious metals, comprising an oxide body 1, the oxide body 1 including an integrally formed bottom 12 and a side wall 11, a graphite outer layer 2 sleeved on the outer periphery of the side wall 11, the bottom end of the graphite outer layer 2 being flush with the bottom 12 of the oxide body 1, and a plurality of protrusions 21 provided on the top end of the graphite outer layer 2, the protrusions 21 being inwardly engaged with the top end of the side wall 11 of the oxide body 1, and a filler 3 being filled between the side wall 11 of the oxide body and the graphite outer layer 2.

[0024] There are at least two bosses 21, possibly two or four, which further enhance the internal and external fixing effect, making the connection between the inner oxide body and the graphite outer layer more stable and reliable. In practical use, regardless of the external impact or internal pressure changes the crucible is subjected to, it can maintain good structural stability, greatly improving the overall stability of the crucible and providing a solid guarantee for the smelting process of precious metals.

[0025] In addition, the protrusion 21 also helps to ensure the rigidity of the gate, making it less prone to deformation during high-temperature melting and casting.

[0026] The filler 3 enables a tight bond between the inner and outer layers of the crucible, effectively reducing heat loss and improving energy efficiency. Furthermore, during the melting process, the filler can uniformly transfer heat, allowing the precious metal within the inner oxide layer to heat up rapidly, shortening the melting time. In addition, the filler also acts as a buffer, reducing thermal stress between the inner and outer layers and lowering the risk of crucible breakage. The filler 3 can be a binder. In some preferred embodiments, the binder is a high-temperature adhesive or a powder mixture of water glass and oxides, which is both heat-resistant and has good thermal conductivity.

[0027] In some preferred embodiments, a rounded corner 14 is provided at the connection between the bottom 12 and the inner sidewall 11 of the oxide body 1. During the inclined casting process, the rounded corner 14 ensures that the molten metal flows smoothly out of the crucible without remaining at the bottom. This avoids metal waste and reduces the difficulty of subsequent cleaning. Simultaneously, the rounded corner 14 helps alleviate thermal stress, allowing the crucible to better withstand the effects of thermal expansion and contraction during high temperatures and cooling, thus extending the crucible's service life.

[0028] Preferably, the fillet radius is 10-30mm, which can withstand higher temperatures and has a longer service life.

[0029] The oxide body 1 of the composite crucible of this invention can be an oxide crucible suitable for precious metal smelting, such as an alumina body, a zirconium oxide body, a magnesium oxide body, or a calcium oxide body.

[0030] In some preferred embodiments, the sidewall thickness of the oxide body is 10mm-15mm, the bottom thickness is 15mm-20mm, and the thickness of the graphite outer layer is 20mm-30mm. This allows for a good match between the inner and outer layers, resulting in good heat resistance and a long service life.

[0031] This invention relates to a high-cleanliness composite crucible for precious metal smelting. During assembly, the inner oxide layer is first inserted into the outer graphite layer, then the filler is added, and finally the assembled crucible is placed inside a water-cooled induction coil. This design avoids direct contact between the precious metal solution and the graphite, while also solving the heating problem of traditional oxide crucibles. Furthermore, the filling material combined with bosses provides fixation; in particular, the bosses effectively prevent the inner layer from detaching during use, ensuring the safety of the smelting process.

[0032] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0033] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A high-cleanliness composite crucible for smelting precious metals, characterized in that, The oxide body (1) includes an integrally formed bottom (12) and sidewall (11). A graphite outer layer (2) is fitted around the outer periphery of the sidewall (11). The bottom end of the graphite outer layer (2) is flush with the bottom (12) of the oxide body. At least two protrusions (21) are provided at the top end of the graphite outer layer (2). The protrusions (21) are inwardly engaged with the top end of the sidewall (11) of the oxide body. A filler (3) is filled between the sidewall (11) of the oxide body and the graphite outer layer (2).

2. The composite crucible according to claim 1, characterized in that, The filler (3) is an adhesive.

3. The composite crucible according to claim 2, characterized in that, The adhesive is a high-temperature adhesive.

4. The composite crucible according to claim 1, characterized in that, The oxide body has a rounded corner (14) at the connection between the bottom (12) and the inner side of the sidewall (11).

5. The composite crucible according to claim 4, characterized in that, The radius of the fillet is 10mm-30mm.

6. The composite crucible according to claim 1, characterized in that, The oxide body (1) is an aluminum oxide body, a zirconium oxide body, a magnesium oxide body, or a calcium oxide body.

7. The composite crucible according to claim 1, characterized in that, The oxide body has a sidewall thickness of 10mm-15mm, a bottom thickness of 15mm-20mm, and a graphite outer layer thickness of 20mm-30mm.

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