阅读说明：本技术 一种新型的金属镁还原罐及其制造方法 (Novel metal magnesium reduction tank and manufacturing method thereof ) 是由 陈玉虎 田守信 于 2021-09-15 设计创作，主要内容包括：本发明提出了一种新型的金属镁还原罐及其制造方法,所述金属镁还原罐包括复合内胆以及紧密套设在复合内胆外围且一端封堵的金属外套管,复合内胆包括两端开口且内部呈中空状的高温化合物内管组以及封堵设置在高温化合物内管组一端的挡板,高温化合物内管组由若干分节设置的高温化合物内管依次插装固定连接而成。本发明将高温化合物内管组分节设置,使得高温化合物内管组制作方便,抗热震性能好,在连接处能够释放热应力,避免出现开裂破坏的情况,热态强度高,大大地延长了还原罐整体的使用寿命。(The invention provides a novel metal magnesium reduction tank and a manufacturing method thereof, wherein the metal magnesium reduction tank comprises a composite inner container and a metal outer sleeve which is tightly sleeved on the periphery of the composite inner container and one end of the metal outer sleeve is plugged, the composite inner container comprises a high-temperature compound inner tube group with openings at two ends and a hollow interior and a baffle plate which is plugged at one end of the high-temperature compound inner tube group, and the high-temperature compound inner tube group is formed by sequentially inserting and fixedly connecting a plurality of high-temperature compound inner tubes which are arranged in sections. The high-temperature compound inner pipe group is arranged in a segmented manner, so that the high-temperature compound inner pipe group is convenient to manufacture and good in thermal shock resistance, can release thermal stress at a joint, avoids cracking damage, is high in thermal state strength, and greatly prolongs the service life of the whole reduction tank.)

1. The utility model provides a novel magnesium metal reduction jar, its characterized in that, establish at the peripheral metal outer tube (1) of just one end shutoff of compound inner bag (2) including compound inner bag (2) and inseparable cover, compound inner bag (2) include both ends opening and inside be hollow high temperature compound inner tube group and shutoff setting baffle (4) of nest of tubes one end in high temperature compound, high temperature compound inner tube group is formed by high temperature compound inner tube (3) that a plurality of sections set up cartridge fixed connection in proper order.

2. The magnesium reduction pot according to claim 1, wherein the high-temperature compound inner tube (3) is made of two or more materials selected from silicon carbide, boron nitride, silicon nitride and vanadium carbide.

3. The magnesium reduction pot according to claim 2, wherein the high temperature compound inner tube (3) is provided with a silicon nitride layer, a vanadium carbide layer, a boron nitride layer and a silicon carbide layer in sequence from outside to inside, and a gap filler for ensuring tight connection of the layers is filled between the layers.

4. A novel magnesium metal reduction tank as claimed in claim 3, wherein said gap filler is silicon carbide powder.

5. The novel metallic magnesium reduction tank according to claim 1, wherein the high temperature compound inner pipes (3) are inserted in sequence in a snap-fit manner and the high temperature compound inner pipes (3) are bonded together by a high temperature bonding agent.

6. The novel metal magnesium reduction pot according to claim 1, characterized in that the inner wall of the composite inner container (2) is uniformly coated with an inner coating for relieving the stress generated to the composite inner container when the materials are thermally expanded.

7. The novel metal magnesium reduction tank as claimed in claim 6, wherein the inner coating is composed of silicon carbide, boron nitride, vanadium carbide powder and an adhesive, the particle size of the powder is 10-300 μm, and the mass ratio of silicon carbide, boron nitride and vanadium carbide is 0.1-1: 0.5-0.8: 0.2-0.6.

8. A novel metallic magnesium reduction tank according to claim 1, characterized in that the material of said metal jacket pipe (1) is heat-resistant stainless steel.

9. A novel method of manufacturing a metallic magnesium reduction tank according to any one of claims 1 to 8, characterized by performing the following steps:

s1, coiling the heat-resistant stainless steel into a steel pipe, coating high-temperature glue on the snap buttons of the high-temperature compound inner pipes (3), and sequentially inserting and pressing the high-temperature compound inner pipes (3) to form a high-temperature compound inner pipe group;

s2, according to requirements, one of the following two sleeving modes is selected to sleeve the high-temperature compound inner pipe group and the metal outer sleeve (1):

A. heating the stainless steel pipe to a certain temperature, then inserting the high-temperature compound inner pipe (3), cooling down, plugging one end of the high-temperature compound inner pipe group by the baffle plate, covering a heat-resistant stainless steel plate (5) on the outer side of the baffle plate, and welding the heat-resistant stainless steel plate (5);

B. a high-temperature compound inner pipe (3) is arranged in a metal outer sleeve (1) at normal temperature, one end of the high-temperature compound inner pipe group is blocked by a baffle, a heat-resistant stainless steel plate (5) is covered on the outer side of the baffle, and the heat-resistant stainless steel plate (5) is welded.

Technical Field

The invention relates to the technical field of reduction tanks, in particular to a novel metal magnesium reduction tank and a manufacturing method thereof.

Background

The conventional reduction pot production process mainly comprises the following steps: smelting heat-resistant stainless steel into molten steel, centrifugally casting into a casting pipe, sand-casting a cap head, and welding the cap head and the tank body together. The pressure test reduction tank body and the cap head are welded and sealed, and air tightness is guaranteed. The research on the process and equipment for smelting magnesium by Pidgeon process is not much, and the process and equipment are not substantially changed so far. The reduction tank can be divided into metal materials and metal and nonmetal composite materials according to the material.

1) The heat-resistant steel of the metal reduction pot is the most widely used material for manufacturing the reduction pot with relatively mature manufacturing technology. For a long time, people have carried out a great deal of research on the manufacturing technology of the heat-resistant steel reduction tank, and the quality of the reduction tank is improved and the service life of the reduction tank is prolonged to different degrees by means of alloying, component adjustment, ingredient optimization, smelting control, casting process, tank body structure improvement and the like. However, due to the limitation of the properties of the materials, the service life of the reduction tank made of the heat-resistant steel material cannot be greatly prolonged. The service life is generally maintained at about 60 days.

2) The composite material reduction pot uses carbon steel or nickel-free, low-nickel heat-resistant steel and other metal materials as a substrate from the last 60 years, and various coatings are covered on the surface of the substrate to be used as a protective layer, so that the research on manufacturing the reduction pot with a composite structure is researched, and the history of manufacturing the magnesium-smelting reduction pot by using a composite material technology is initiated. In recent years, the technical invention activity in the aspect of manufacturing the reduction tank by adopting a composite mode is quite active, and the prospect of the composite material reduction tank is promising, but the application effect is not obviously improved so far.

3) The main starting point of using the non-metal material in the non-metal material reduction tank is to resist high-temperature oxidation and corrosion, and the necessary consideration is lacked for the relevant problems of strength, air tightness, heat efficiency, thermal shock resistance and the like of the reduction tank. Reliable technical data for practical use and authoritative reports of successful application are not seen at present. The reduction tank is made of materials which are basically cast by high-chromium nickel alloy steel, and has short service life, generally about 2 months. Therefore, the production cost of the reduction tank is high, and the problem is always a concern for magnesium smelters. The strength of the oxidizing atmosphere of the flue gas in the furnace is an important factor influencing the service life of the tank. At present, the alloy steel available for manufacturing the reduction tank in China is less. The maximum oxidation resistance critical temperature of the alloy steel is only 1200 ℃. Because the alloy steel tank is used at the upper limit of the anti-oxidation critical temperature for a long time, the surface is oxidized, the phenomena of peeling, oxide layer peeling, re-oxidation and the like are generated, and the tank wall is gradually thinned, so that the tank body is damaged.

The service life of the reduction tank is related to the following factors: firstly, the oxygen content in the flue gas is high, and the oxidation is accelerated; secondly, the sulfur content in the flue gas is high, and the flue gas has strong corrosivity to the tank; the temperature exceeds the limit of the anti-oxidation critical temperature, so that the oxidation of the tank can be accelerated; fourthly, the higher the temperature is, the lower the mechanical strength of the alloy steel tank is, and the problems of crushing deformation and even cracking are caused particularly under vacuum; the quality, the manufacturing method and the welding quality of the alloy steel also influence the service life of the tank; sixthly, adding the raw material temperature, which directly influences the fluctuation of the temperature to promote the formation and the propagation of cracks. In order to prolong the service life, various measures such as coating, structure improvement, material improvement, compounding of various materials and the like are carried out. However, up to now, there has been no breakthrough in the service life of the magnesium reduction pot. The following are now divided:

in order to prevent the reduction tank from being shrunken, a method of reinforcing ribs is adopted for the reduction tank so as to improve the ability of resisting the shrunken and the cracks. For example, the novel seven-angle metal magnesium reduction tank reported in the Chinese patent with the application number of CN200810003629.6 and Huxiang Yong increases the rigidity at high temperature and reduces the high-temperature creep. The wall thickness can be reduced on the premise of the same volume, so that the total mass of the tank is reduced by more than 20-30%, and the cost for producing the metal magnesium is reduced. However, the report does not jump over the rings made of metal materials, even if the stainless steel is heat-resistant, the problems of high price, low thermal state strength, low oxidation and use temperature are not fundamentally solved, and the improvement of the cost performance is limited.

In order to improve the deformation resistance and the use temperature of the reduction pot, the chinese utility model patent application No. CN201220020617.6 is similar to the chinese invention patent application No. CN 201710093723.4. In the former, an inner tube made of silicon carbide, bauxite or/and corundum is sleeved in a stainless steel tank body. It is desirable that the inner liner tube has high hot strength to support deformation of the outer tank. This patent actually has many problems, such as not describing the method of manufacturing the inner tube, and only a combination of several raw materials cannot be a good product, and the performance of the product is not good or even much worse than that of the stainless steel can. And secondly, the alumina or corundum oxide causes low heat conductivity coefficient, seriously influences the heat transfer of the tank and possibly reduces the production efficiency by more than 50 percent. For example, the thermal conductivity of corundum silicon carbide refractory materials is only 5 w/(mk). The latter is that the inner layer is ceramic tube, and the high nickel stainless steel is cast into the outer tank body, so that the high temperature support problem is solved because the high temperature strength of the ceramic is high. It is known that the thermal conductivity of ceramics is generally less than half of that of metals, which seriously affects the production efficiency and even decreases by more than 50%. And the brittleness of the ceramic material is too great, which will also seriously affect the service life of the tank body. There are also patents similar to reduction pots made of non-oxide layers and heat-resistant stainless steel layers, which have the common disadvantage of slow heat conduction and poor gas permeability, and thus lose value.

The Chinese invention patent with the application number of CN201710093491.2 and the Chinese utility model patent with the application number of CN200720200207.9 are both tank bodies formed by compounding two metals or alloys in two layers. The former is a double-layer structure with an outer layer made of high-nickel stainless steel and an inner sleeve made of low-cost common carbon steel cylinder. This appears to reduce costs, but the service life is significantly reduced due to the reduced hot strength of plain carbon steel, and may be irreparable. The latter is coated with a layer of GZ with a thickness of 1-20 mm and a higher grade₃₅Gr₂₅Ni₃₅And (4) an RE reduction tank. Because of the adoption of higher-grade materials, the manufacturing complexity is caused, and the improvement of the comprehensive effect is not obvious.

Chinese patent application No. CN201010171670.1 discloses a magnesium smelting reduction pot with an external coating layer. The high-temperature resistant coating is coated on the surface of a reduction tank, and the main components of the external coating layer are zircon powder or graphite, bentonite and a small amount of organic binder. Since the glaze layer is not formed, the coating is porous and has little resistance to oxidation of the reduction pot. In particular, the coating has a very low thermal conductivity, which may be less than 5% of that of the metal can. This means that the production efficiency is significantly reduced and therefore the coating layer is not advantageous.

Disclosure of Invention

The invention provides a novel magnesium metal reduction tank and a manufacturing method thereof, which aim to solve the problems in the background technology, prolong the service life of the magnesium metal reduction tank and reduce the manufacturing cost.

The technical scheme of the invention is realized as follows:

the utility model provides a novel metal magnesium reduction jar, includes that compound inner bag and inseparable cover establish at the peripheral metal outer tube that just one end shutoff of compound inner bag, compound inner bag include both ends opening and inside be the interior nest of tubes of hollow form high temperature compound and shutoff setting up the baffle of nest of tubes one end in high temperature compound, the nest of tubes is formed by the high temperature compound inner tube cartridge fixed connection in proper order that a plurality of sections set up in the high temperature compound.

The high-temperature compound mainly refers to carbide, nitride, boride and silicide with good thermal conductivity and high temperature resistance.

According to the technical scheme, the high-temperature compound inner tube is made of two or more materials of silicon carbide, boron nitride, silicon nitride or vanadium carbide. According to the technical scheme, the high-temperature compound inner tube is sequentially provided with a silicon nitride layer, a vanadium carbide layer, a boron nitride layer and a silicon carbide layer from outside to inside, and gap fillers used for ensuring tight connection of the layers are filled between the layers.

Further optimizing the technical scheme, the gap filler is silicon carbide powder.

According to the technical scheme, the high-temperature compound inner pipes are sequentially inserted in a snap fastener mode and are bonded through a high-temperature bonding agent.

Further optimizing the technical scheme, the inner wall of the composite liner is uniformly coated with an inner coating for relieving stress generated on the composite liner when materials are thermally expanded.

The technical scheme is further optimized, the inner coating is composed of silicon carbide, boron nitride, vanadium carbide powder and an adhesive, the particle size of the powder is 10-300 mu m, and the proportion of the silicon carbide: boron nitride: 0.1-1% of vanadium carbide: 0.5-0.8: 0.2-0.6.

Further optimize the technical scheme, the material of metal outer tube is heat-resisting stainless steel.

A novel method for manufacturing a magnesium metal reduction tank comprises the following steps:

s1, coiling the heat-resistant stainless steel into a steel pipe, coating high-temperature glue on the primary and secondary buckles of each high-temperature compound inner pipe, and sequentially inserting and pressing each high-temperature compound inner pipe to form a high-temperature compound inner pipe group;

s2, sleeving the high-temperature compound inner tube group and the metal outer sleeve by selecting one of the following two sleeving modes according to requirements:

A. heating the stainless steel pipe to a certain temperature, then inserting the high-temperature compound inner pipe, cooling down, plugging one end of the high-temperature compound inner pipe group by the baffle plate, covering a heat-resistant stainless steel plate on the outer side of the baffle plate, and welding the heat-resistant stainless steel plate;

B. the high-temperature compound inner pipe is arranged in the metal outer sleeve at normal temperature, one end of the high-temperature compound inner pipe group is blocked by the baffle, the heat-resistant stainless steel plate is covered on the outer side of the baffle, and the heat-resistant stainless steel plate is welded.

By adopting the technical scheme, the invention has the beneficial effects that:

the high-temperature compound inner pipe group is arranged in a segmented manner, so that the high-temperature compound inner pipe group is convenient to manufacture and good in thermal shock resistance, can release thermal stress at a joint, avoids cracking damage, is high in thermal state strength, and greatly prolongs the service life of the whole reduction tank.

The invention has very wide application prospect, the manufacturing cost is reduced by more than 40% after the implementation, the service life is prolonged by more than 3 times compared with the service life in the prior art, and the social and economic benefits are very obvious; meanwhile, the invention also has good environmental protection value of energy conservation and emission reduction.

The outer pipe is a heat-resistant stainless steel pipe, the inner pipe is a high-heat-conductivity silicon carbide pipe, the heat-resistant stainless steel pipe and the silicon carbide pipe are combined together in a plug-in assembly mode, the heat-resistant stainless steel on the outer layer plays a role in sealing, air leakage is prevented, vacuum in the tank is guaranteed, and conditions are created for reducing metal magnesium. In order to ensure high-efficiency heat transfer, the inner tube is made of a silicon carbide material with high thermal conductivity, and the silicon carbide inner tube is made by adopting a manufacturing process of a refractory material instead of a ceramic manufacturing method, so that the silicon carbide inner tube has high strength and good thermal conductivity and thermal shock resistance. When the inner pipe and the outer pipe are assembled in a hot mode, the outer pipe is heated to be more than 800 ℃ first, and the inner pipe is sleeved with the outer pipe. After cooling down, the inner and outer tubes are tightly bonded together. When the mode of assembling the inner pipe and the outer pipe at normal temperature is adopted, the gaps of the inner pipe and the outer pipe are reduced as much as possible. The magnesium smelting reduction pot has low cost and high use efficiency, has the service life as long as 8 months, and improves the service life by more than 3 times compared with the service life in the prior art.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a sectional view of a novel magnesium metal reduction pot according to the present invention;

FIG. 2 is a schematic structural view of a novel magnesium metal reduction tank according to the present invention;

FIG. 3 is a schematic structural view of a first inner tube of a novel magnesium metal reduction tank according to the present invention;

FIG. 4 is a schematic structural view of a second inner tube of a novel magnesium metal reduction tank according to the present invention;

FIG. 5 is a schematic structural view of a third inner tube of a novel magnesium metal reduction tank according to the present invention;

FIG. 6 is a schematic structural diagram of the novel magnesium metal reduction tank with two high-temperature compound inner tubes inserted.

Wherein: 1. the composite liner comprises a metal outer sleeve, 2, a composite inner container, 3, a high-temperature compound inner tube, 31, a first inner tube, 311, a first groove, 32, a second inner tube, 321, a first convex tube, 322, a second groove, 33, a third inner tube, 331, a second convex tube, 4, a baffle, 5 and a heat-resistant stainless steel plate.

Detailed Description

The technical solutions of the present invention will be clearly and completely described below in connection with specific embodiments, but it should be understood by those skilled in the art that the embodiments described below are only for illustrating the present invention and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A novel metal magnesium reduction tank is shown in figures 1 to 6 and comprises a composite inner container 2 and a metal outer sleeve 1.

The metal outer sleeve 1 is tightly sleeved on the periphery of the composite liner 2, and one end of the metal outer sleeve is plugged. The metal outer sleeve 1 is made of heat-resistant stainless steel and has a thickness of 15-35 mm. Can be welded by a coiled steel plate or can be made by casting. The metal outer sleeve 1 mainly has the function of providing mechanical strength for the tank body foundation and ensuring that the composite inner container of the tank body is not broken in the process of high-temperature magnesium smelting. The vacuum pressure rise rate of the sealed tank body is less than 1Pa/min, and the maximum internal pressure resistance is 5 MPa. The metal outer sleeve 1 plays a role in sealing, and is airtight under the vacuum condition, so that the reaction for generating the metal magnesium is ensured to be carried out in vacuum.

The metal outer sleeve 1 is welded with a heat-resistant stainless steel plate 5, one end of the metal outer sleeve 1 is open, and the other end of the metal outer sleeve 1 is welded with the heat-resistant stainless steel plate 5.

The composite liner 2 comprises a high-temperature compound inner tube group and a baffle 4. The high-temperature compound inner tube group is provided with openings at two ends and is hollow inside. The high-temperature compound inner pipe group is formed by sequentially inserting and fixedly connecting a plurality of high-temperature compound inner pipes 3 which are arranged in sections, namely the high-temperature compound inner pipe group is formed by assembling sections.

The advantages of the multi-section combination are: 1) the manufacture is convenient; the common press machine is difficult to manufacture large refractory materials, and the inner pipe of the high-temperature compound is arranged in sections so as to be convenient to manufacture. 2) The small piece has good thermal shock resistance; the high-temperature compound inner pipe at the joint can release thermal stress, and cracking damage is avoided. 3) The joints are uniformly coated with the silicone resin high-temperature bonding agent and connected together, so that the high-temperature-resistant and high-temperature-resistant composite material is high in temperature resistance and high in strength, and can approach the strength of products. 4) The inner tube of the multi-section high-temperature compound has good performance, particularly high thermal state strength, so the service life is long.

The high-temperature compound inner tube 3 and the metal outer sleeve 1 are both arranged in a circular tube shape.

The high-temperature compound inner tube 3 is made of one or the combination of any more of carbide, nitride, silicide and boride. Specifically, the high-temperature compound inner tube 3 is made of two or more materials of silicon carbide, boron nitride, silicon nitride or vanadium carbide.

The high-temperature compound inner pipe 3 can be arranged in a layered mode or not.

The high-temperature compound inner pipes 3 are sequentially inserted in a snap fastener mode, and the high-temperature compound inner pipes 3 are bonded through a high-temperature bonding agent. Each section adopts a snap fastener form, and during assembly, a high-temperature binding agent is coated on the snap fastener and then inserted into the snap fastener to form tight fit.

The high-temperature compound inner pipe group includes a first inner pipe 31 disposed at an end portion, a plurality of second inner pipes 32 disposed at a middle portion, and a third inner pipe 33 disposed at the other end portion. One end of the first inner tube 31 is flush with the end surface of the metal outer sleeve 1, and the other end surface of the first inner tube 31 is provided with a first groove 311. One end of the second inner pipe 32 is provided with a first convex pipe 321 fitted with the first groove 311, and the other end of the second inner pipe 32 is provided with a second groove 322, which is matched with the first convex pipe of the next adjacent second inner pipe. One end of the third inner tube 33 is provided with a second convex tube 331 matching with the second concave groove of the second inner tube 32.

The baffle 4 is plugged at one end of the high-temperature compound inner pipe group. The material of the baffle 4 of the invention is the same as that of the high-temperature compound inner pipe 3.

In order to relieve the stress on the composite liner during the thermal expansion of materials in the high-temperature process of magnesium smelting, the inner wall of the composite liner 2 is uniformly coated with an inner coating, the thickness of the inner coating is 0.1-1.5 mm, and the service life of the composite liner can be prolonged.

The inner coating is composed of silicon carbide, boron nitride, vanadium carbide powder and an adhesive, the particle size of the powder is 10-300 mu m, and the mass ratio of the silicon carbide to the boron nitride to the vanadium carbide is 0.1-1: 0.5-0.8: 0.2-0.6. The adhesive is sodium silicate aqueous solution, and the mass ratio of the adhesive to the powder is 1: 10-50. The mixed coating material is stirred and evenly coated on the inner wall of the composite liner to form a protective layer, the compounding proportion of the inner coating material is crucial in the invention, on one hand, the coating material is not easy to fall off and crack, on the other hand, the coating material is also high temperature resistant and has a certain protective effect on the liner to prolong the service life of the liner, and the silicon carbide, the boron nitride and the vanadium carbide are reasonably compatible and cooperate to protect the composite liner, thereby prolonging the service life of the composite liner.

A novel method for manufacturing a magnesium metal reduction tank comprises the following steps:

s1, coiling the heat-resistant stainless steel into a steel pipe, coating high-temperature glue on the snap buttons of the high-temperature compound inner pipes 3, and sequentially inserting and pressing the high-temperature compound inner pipes 3 to form a high-temperature compound inner pipe group.

S2, if necessary, one of the following two fitting methods is selected to fit the high-temperature compound inner tube group and the metal outer tube 1.

A. Heating the stainless steel pipe to above 800 ℃, inserting the high-temperature compound inner pipe 3, cooling down, contracting the high-temperature compound inner pipe and the metal outer sleeve, tightly hooping the high-temperature compound inner pipe and the metal outer sleeve together, blocking one end of the high-temperature compound inner pipe group by the baffle, covering a heat-resistant stainless steel plate 5 on the outer side of the baffle, and welding the heat-resistant stainless steel plate 5.

B. And a cold sleeving mode is adopted. The high-temperature compound inner pipe 3 is arranged in the metal outer sleeve 1 at normal temperature, one end of the high-temperature compound inner pipe group is blocked by the baffle, the heat-resistant stainless steel plate 5 is covered on the outer side of the baffle, and the heat-resistant stainless steel plate 5 is welded to realize the sealing of one end. When the inner pipe and the outer pipe are assembled at normal temperature, the gaps of the inner pipe and the outer pipe are reduced as much as possible. The magnesium smelting reduction pot has low cost and high use efficiency, and the service life is as long as 8 months and is improved by more than 3 times.

The metal outer sleeve is a heat-resistant stainless steel pipe, and the inner pipe is a pipe made of silicon carbide as a main component. The thickness of the inner pipe is 15-35 mm, preferably the thickness of the inner pipe is less than or equal to 20mm, the inner pipe is formed by combining a plurality of sections, the length of each section is 100-500 mm, the two ends of each section are in a snap fastener mode, each section is firmly connected, and in the connection process, the sections are combined through high-temperature silica gel. The thickness of the heat-resistant stainless steel outer pipe is 15-35 mm, the outer pipe plays a role in sealing, air leakage is avoided under the vacuum condition, and the reaction for generating metal magnesium in vacuum is guaranteed. The composition of the inner tube is 65% of SiC, the apparent porosity is less than 16%, the high-temperature breaking strength at 1400 ℃ is 10MPa, and the thermal conductivity is 20w/(mk), thereby playing an important role in heat conduction and high-temperature support.

Example 1

In the embodiment, the high-temperature compound inner tubes 3 are arranged in layers, the silicon nitride layer is tightly attached to the inner wall of the metal shell, the vanadium carbide layer, the boron nitride layer and the silicon carbide layer are arranged inwards in sequence, and the thickness of each layer is 0-15 mm.

In the process of smelting magnesium at high temperature, in order to promote the stroke solid phase connection among the layers, the gap filler is filled among the layers and is used for ensuring the close connection of the layers. The joint mixture in the invention is silicon carbide powder. The thermal expansion coefficients of the layers have certain difference, and the difference of the thermal expansion coefficients of the layers can improve the inner wall fracture of the cylindrical high-temperature compound inner pipe caused by self thermal expansion and the outer wall fracture generated in cooling.

Example 2

The mass ratio of the undercoat silicon carbide, boron nitride, and vanadium carbide powder of this example was 0.1: 0.6: 0.4, the mass ratio of the adhesive to the powder is 1: 20.

this example is a manufacturing process of a magnesium metal reduction pot:

a heat-resistant stainless steel plate with the thickness of 10mm is adopted and is curled into a steel pipe with the diameter of 360mm and the length of 2700mm, then the snap buttons of the silicon carbide inner pipes with the outer diameter of 340mm, the inner diameter of 285mm and the length of 300mm are coated with high-temperature glue, and 9 silicon carbide inner pipes are sequentially inserted and compressed to form a silicon carbide inner pipe group. The stainless steel tube was then heated to 800 ℃ and the silicon carbide inner tube set was inserted into the stainless steel tube. After cooling down, a silicon carbide plate with the diameter of 340mm and the thickness of 40mm is pluggedCovering a heat-resistant stainless steel plate with the diameter of 360mm and the thickness of 30mm, and welding the heat-resistant stainless steel plate by argon arc to obtain the magnesium-smelting vacuum reduction tank. The density of the silicon carbide inner tube is 2.65g/cm³Porosity of 15%, SiC + Si₃N₄The heat transfer efficiency is high, the time for producing the magnesium metal is short, and the production efficiency is high. Because the strength of the supporting silicon carbide inner tube is high, the supporting silicon carbide inner tube is not aged, and the heat-resistant stainless steel only plays a role in sealing and does not bear load. Therefore, the service life is greatly prolonged to more than 8 months.

Example 3

The mass ratio of the undercoat silicon carbide, boron nitride, and vanadium carbide powder of this example was 0.5: 0.5: 0.6, the mass ratio of the adhesive to the powder is 1: 10.

this example is a manufacturing process of a magnesium metal reduction pot:

a heat-resistant stainless steel plate with the thickness of 15mm is adopted and is curled into a steel pipe with the diameter of 370mm and the length of 2800mm, then snap buttons of silicon carbide inner pipes with the outer diameter of 340mm, the inner diameter of 280mm and the length of 200mm are coated with high-temperature glue, and 14 silicon carbide inner pipes are sequentially inserted and compressed to form a silicon carbide inner pipe group. Then heating the stainless steel pipe to 1000 ℃, inserting the silicon carbide inner pipe into the stainless steel pipe, cooling down, blocking one end of a silicon carbide plate with the diameter of 340mm and the thickness of 40mm, covering a heat-resistant stainless steel plate with the diameter of 370mm and the thickness of 30m, and welding the heat-resistant stainless steel plate by argon arc to obtain the magnesium-smelting vacuum reduction tank. The density of the silicon carbide inner tube is 2.56g/cm³Porosity of 18%, SiC content of 85% or more, SiO₂Less than or equal to 15 percent, the hot state strength at 1400 ℃ is more than or equal to 30MPa, the heat conductivity coefficient is 17w/(mk), and the heat conductivity coefficient is larger than that of heat-resistant stainless steel, so the heat transfer efficiency is high, the time for producing metal magnesium is short, and the production efficiency is high. Because the supporting silicon carbide pipe has high strength and is not aged, the heat-resistant stainless steel only plays a role in sealing and does not bear load, the service life is greatly prolonged and can reach more than 8 months.

Example 4

The mass ratio of the undercoat silicon carbide, boron nitride, and vanadium carbide powder in this example was 1: 0.8: 0.2, the mass ratio of the adhesive to the powder is 1: 50.

this example is a manufacturing process of a magnesium metal reduction pot:

the method comprises the steps of adopting heat-resistant stainless steel, melting and casting the heat-resistant stainless steel into a steel pipe with the inner diameter of 340mm, the wall thickness of 20mm and the length of 3150mm, then coating high-temperature glue on snap buttons of silicon carbide inner pipes with the outer diameter of 335mm, the inner diameter of 295mm and the length of 300mm, and sequentially inserting and pressing 10 silicon carbide inner pipes to form a silicon carbide inner pipe group. Then heating the stainless steel tube to 1200 ℃, inserting the silicon carbide inner tube into the stainless steel tube, cooling down, plugging one end of a silicon carbide plate with the diameter of 335mm and the thickness of 40mm, covering a heat-resistant stainless steel plate with the diameter of 380mm and the thickness of 20mm, and welding the heat-resistant stainless steel plate by argon arc to obtain the magnesium-smelting vacuum reduction tank. The density of the silicon carbide inner tube is 2.62g/cm³The porosity is 12 percent, the SiC is more than or equal to 92 percent, the hot state strength at 1400 ℃ is more than or equal to 40MPa, the heat conductivity coefficient is 20w/(mk), and the heat conductivity coefficient is larger than that of heat-resistant stainless steel, so the heat transfer efficiency is high, the time for producing metal magnesium is short, and the production efficiency is high. Because the strength of the supporting silicon carbide inner tube is high, the supporting silicon carbide inner tube is not aged, and the heat-resistant stainless steel only plays a role in sealing and does not bear load, the service life is greatly prolonged and can reach more than 10 months.

Example 5

The mass ratio of the undercoat silicon carbide, boron nitride, and vanadium carbide powder of this example was 0.5: 0.8: 0.5, the mass ratio of the adhesive to the powder is 1: 30.

this example is a manufacturing process of a magnesium metal reduction pot:

melting heat-resistant stainless steel, centrifugally casting into a steel pipe with the inner diameter of 340mm, the outer diameter of 380mm, the wall thickness of 20mm and the length of 3150mm, coating high-temperature glue on the top of a silicon carbide inner pipe with the outer diameter of 340mm, the inner diameter of 300mm and the length of 150mm, and sequentially propping and compressing 20 silicon carbide inner pipes. And heating and hardening the high-temperature adhesive by using electric welding fire. Then inserting the silicon carbide inner tube into the stainless steel tube, plugging one end of a silicon carbide plate with the diameter of 340mm and the thickness of 40mm, adopting a heat-resistant stainless steel plug with the diameter of 370mm and the thickness of 35mm, and welding the plug by argon arc to obtain the magnesium-smelting vacuum reduction tank. The density of the silicon carbide tube is 2.62g/cm³The porosity is 12 percent, the SiC is more than or equal to 92 percent, the hot state strength at 1400 ℃ is more than or equal to 40MPa, the heat conductivity coefficient is 20w/(mk), and the heat conductivity coefficient is larger than that of heat-resistant stainless steel, so the heat transfer efficiency is high, the time for producing metal magnesium is short, and the production efficiency is high. Because the strength of the supporting silicon carbide inner tube is high, the supporting silicon carbide inner tube is not aged, and the heat-resistant stainless steel only plays a role in sealing and does not bear load, the service life is greatly prolonged and can reach more than 10 months.

Example 6

The mass ratio of the undercoat silicon carbide, boron nitride, and vanadium carbide powder of this example was 0.7: 0.5: 0.2, the mass ratio of the adhesive to the powder is 1: 40.

this example is a manufacturing process of a magnesium metal reduction pot:

a heat-resistant stainless steel plate with the thickness of 35mm is adopted and is curled into a steel pipe with the diameter of 360mm and the length of 2700mm, then snap buttons of silicon carbide inner pipes with the outer diameter of 290mm, the inner diameter of 220mm and the length of 100mm are coated with high-temperature glue, and 27 silicon carbide inner pipes are sequentially inserted and compressed to form a silicon carbide inner pipe group. The stainless steel tube was then heated to 800 ℃ and the silicon carbide inner tube set was inserted into the stainless steel tube. After cooling down, one end of a silicon carbide plate with the diameter of 290mm and the thickness of 40mm is plugged, a heat-resistant stainless steel plate with the diameter of 360mm and the thickness of 30mm is covered, and the heat-resistant stainless steel plate is welded by argon arc, thus obtaining the magnesium-smelting vacuum reduction tank. The density of the silicon carbide inner tube is 2.7g/cm³The porosity is 12 percent, the SiC is more than or equal to 92 percent, the hot state strength at 1400 ℃ is more than or equal to 40MPa, the heat conductivity coefficient is 20w/(mk), and the heat conductivity coefficient is larger than that of heat-resistant stainless steel, so the heat transfer efficiency is high, the time for producing metal magnesium is short, and the production efficiency is high. Because the strength of the supporting silicon carbide inner tube is high, the supporting silicon carbide inner tube is not aged, and the heat-resistant stainless steel only plays a role in sealing and does not bear load.

The invention has very wide application prospect, the manufacturing cost is reduced by more than 40% after the implementation, the service life is also prolonged by more than 3 times, and the social and economic benefits are very obvious; meanwhile, the invention also has good environmental protection value of energy conservation and emission reduction.

Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.