JPS6137339B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a reaction vessel for the reduction of metal chlorides. Among the metal materials, titanium and zirconium, which are high melting point and high toughness metal materials, are mainly produced by reducing their chlorides with magnesium, and are obtained as metal sponges. As used herein, the term high melting point high toughness metal refers to metals produced by the reduction of titanium, zirconium, and similar chlorides. The production of such high-melting-point, high-toughness metal sponges is currently limited to a reduction step in which magnesium is reacted with a chloride of the target metal (e.g., titanium tetrachloride) in a sealed, heatable reaction chamber, followed by a production process. This process involves a vacuum separation process in which by-product magnesium chloride and unreacted magnesium are removed from the sponge metal by vacuum distillation. Materials that are not corroded by magnesium, such as carbon steel and ferritic stainless steel, are currently used industrially for such reaction vessels, but these materials have low heat-resistant strength, and it is difficult to obtain the necessary strength. This increases the thickness of the vessel wall, which inevitably results in an increase in weight, a decrease in thermal efficiency during heating, and a decrease in the accuracy of estimating internal temperature.In addition, the strength decreases at high temperatures, making it easier to deform, which is unavoidable. It has a relatively short service life. Austenitic stainless steel has high heat resistance but is easily attacked by molten magnesium. When using an austenitic stainless steel reaction vessel, it is essential to first charge magnesium chloride to avoid direct contact with molten magnesium, as disclosed in JP-A-57-9847. Devices that use a protective inner cylinder made of a material that does not react with or alloy with magnesium have been proposed. However, the former method is complicated to operate, and the latter method uses a protective inner cylinder in addition to the reaction vessel, which inevitably results in increased weight, decreased thermal efficiency during heating, decreased accuracy in estimating internal temperature, etc. . Generally, in the above-mentioned containers, the target metal is produced as a spongy mass and adheres to the vessel wall, so it must be mechanically removed. Usually, the magnesium chloride discharge pipe installed at the bottom of the container is cut, and a rod pressed by a press is inserted through it.
The protective inner cylinder is taken out. Even when the protective inner cylinder is not used, a perforated plate or similar plate is placed at the bottom of the container to catch the generated spongy metal, and the plate can be taken out. For next use, re-weld and attach the magnesium chloride discharge pipe. When a container is heated to 1081℃ or higher for titanium or 935℃ or higher for zirconium, the spongy metal that forms at the contact area with the container often forms an alloy with iron and firmly adheres to the container. . In this case, it becomes difficult to extract the generated metal. To prevent the formation of such alloys, the inner surface of the container should be
A method of coating with MgO and/or CaO has also been proposed (Japanese Patent Application Laid-Open No. 56-4823). However, since this method simply coats MgO and/or CaO inside the container and bakes it at about 500°C, the strength of the resulting coating layer is low, and during reduction and vacuum separation,
Alternatively, when the product is mechanically removed, the coating layer peels off and becomes an impurity in the product, and the number of times the coating layer can be used is extremely small. The present inventors applied some type of coating to the inner surface of the reaction vessel to prevent erosion by molten magnesium metal and magnesium chloride, and also to withstand mechanical friction during removal of the formed sponge metal, which is more durable than MgO and/or CaO. As a result of searching for a coated material with a large surface area, it was discovered that a carbon stamp material is suitable for this purpose, leading to the present invention. In the present invention, instead of coating the protective inner cylinder or refractory, the inner wall of the reaction vessel is coated with a carbon stamp material that is highly resistant to corrosion against molten magnesium. This enables the use of austenitic stainless steel, reduces resistance when mechanically removing the spongy metal produced, and extends the life of the reaction vessel.
This reduction reaction vessel is characterized in that the inner wall of the reaction vessel is made of austenitic stainless steel such as SUS304, SUS310, or SUS316 and is coated with a carbon stamp material. Carbon stamp material is solid at room temperature (contains hydrogen) and is mainly composed of tar, pitch, etc., which are distillation residues from petroleum refining.
It is heated to about 120℃ to soften it, applied to the surface of the substrate, hardened with a rammer, etc., and fired at about 1000℃ (hydrogen is removed) to form a carbonaceous layer, which can be used for molding. Formulations are commercially available. The method of coating the inner surface of the reaction vessel with the carbon stamp material varies depending on the carbon stamp material provided by each manufacturer, and must follow the usage guidelines attached to the product. For example, NCK stamp paste manufactured by Nippon Carbon Co., Ltd. is made by heating the stamp material to 120°C, tamping it with a rammer, etc., and then heating it to 1000°C.
Heat and bake to a certain degree. In addition, in order to prevent carburization of the walls of the reaction vessel, a cement material made of Al ₂ O ₃ , CaO, MgO, SiO ₂ , ZrO ₂ or a mixture thereof is applied to the inner surface of the reaction vessel. It is desirable to apply a carbon stamp material thereon. Further, in order to facilitate the attachment of the carbon stamp material to the inner wall, a protrusion may be provided on the inner surface of the container. Next, the present invention will be explained in detail with reference to the drawings. FIG.
126936 (Japanese Patent Application No. 57-8771) is a cross-sectional view of an apparatus for producing a high-melting-point, high-toughness metal by reduction of chlorides. This apparatus includes a reaction chamber (retort) 10 that can be heated for reacting a chloride of a high-melting point, high-toughness metal with an active metal to obtain the metal by reducing the chloride of the metal; A protective inner cylinder (inner container) 20 housed therein,
From a condensation chamber 40 that can be cooled under reduced pressure for condensing active metals and by-product chlorides separated from produced metals by evaporation in the reaction chamber, and an intermediate connection section 30 for communicating or blocking these. The apparatus comprises: a funnel-shaped body 38 and its open leg portions received in the intermediate connecting portion; a seal pot means consisting of /36 for holding a readily melting and evaporating substance; and a sealing pot means for melting and evaporating the easily melting liquid evaporating substance. Heating means 70
It is characterized by having the following. In this apparatus, since the protective inner cylinder 20 is used in the reaction chamber 10, the weight is inevitably increased accordingly. In order to reduce the weight as much as possible, in the present invention, the container is made of austenitic stainless steel, the protective inner cylinder is eliminated, and the inner surface is coated with carbon stamp material. Such an apparatus according to one embodiment of the present invention is shown in FIG. Most of the structure of the device is common to both, so detailed explanation will be given in the second part.
Follow the diagram. The device is constructed of austenitic stainless steel. In FIG. 1, the reaction chamber 10 is practically cylindrical, and the protective inner cylinder 20 is a cylinder that is slightly smaller than the reaction chamber, and the bottom part of the protective inner cylinder 20 has at least a cylindrical shape so that the molten magnesium chloride can be discharged. In Fig. 2, there are several small holes.
There is no internal vessel; instead, the inner surface of the reaction vessel is coated with carbon stamp material 10a as described above. A discharge pipe 13 having an opening/closing means 14 such as a valve for discharging magnesium chloride is also provided at the bottom of the reaction chamber. A flange 11 is formed at the upper end of this reaction chamber, and a collar 12 is further provided for suspending the reaction chamber in a heating furnace, which will be described later. The intermediate connection 30 essentially consists of a cylindrical body 31 having a diameter smaller than the internal diameter of the reaction chamber, from its upper end projects a wide flange 32, from its lower end a further flange 33, the middle of the latter a cylindrical wall 3 that is lower than the cylindrical body 30 and extends upwardly from the cylindrical wall 3;
4 is formed, and a flange 35 protrudes from its upper edge. This flange 35 is configured to overlap with the flange 11 of the reaction chamber. The diameter of the flange 33 at the lower end of the intermediate connection is equal to the diameter of the reaction chamber 1.
It is slightly smaller than the inner diameter of 0, and is large enough to fit into the reaction chamber 10 and come into contact with its inner wall. The flange 35 of the intermediate connecting portion and the flange 11 of the reaction chamber are removably fixed with bolts, clamps, etc. with a gasket interposed therebetween. The gasket may be made of known heat resistant elastomers. The condensing chamber is composed of a cooling chamber 40 having a jacket structure and a shape similar to a reaction chamber, and a condensing cylinder 50 housed inside the cooling chamber 40. The cooling chamber 40 has an exhaust port 41, and the jacket has a cooling liquid (water) inlet 4.
2. A discharge port 43 is provided, and the lower end is a flange 44 similar to that of the reaction chamber. The condensing cylinder 50 is a cylindrical container that is one size smaller than the cooling chamber, and has at least one hole in the ceiling to allow gas to pass through. Its lower end forms a flange 52 similar to the cooling chamber. Cooling chamber 40 and condensing cylinder 5
The flanges 44, 52 of 0 and the flange 32 of the intermediate connecting portion 30 are overlapped with a gasket interposed therebetween, and are removably fixed with bolts or the like. However, normally the cooling chamber 40 and the condensing cylinder 50 are treated as one unit as a condensing chamber. The gasket in this part may also be made of a known heat-resistant elastomer. The intermediate connecting portion 30 has a low cylindrical container (pan) 36 in the center of the cylindrical body 31.
A funnel-shaped body 38 is provided above the pan so as to face the pan, the upper end of the conical part is closely fixed to the inner periphery of the intermediate connecting part, and the lower end of the tubular leg is located below the upper edge of the peripheral wall of the pan. is invading. Usually, this intermediate connecting portion 30 is provided with a conduit 61 for introducing a desired metal chloride, an inert gas, etc., and a conduit 62 for exhaust. Although these conduits may be provided in the main body of the reaction chamber 10, it is more convenient to provide them at this intermediate connection. These conduits have a valve not far from the intermediate connection so that they can be removed from the parent pipe outside the valve. In this figure, the conduit on the right is divided into a branch pipe for introducing metal chloride and a branch pipe for introducing inert gas, each of which is equipped with a valve. A conduit 39 for introducing the sealing material 80 into the pan is provided at the upper end of the funnel-shaped part 38 of the intermediate connecting part 30, and heating means, usually Electric resistance heating means 70
is provided. The reaction chamber 10 is housed in a suitable heating device 90. A suitable heating device is of the electrical resistance type. This heating device has an opening for the magnesium chloride discharge pipe of the reaction chamber 10. This heating device can be appropriately designed by a person skilled in the art, and therefore will not be particularly described. The method of operating this device is as follows. After charging the reaction chamber with the magnesium mass, the flanges 11 and 35 are fixed and the intermediate connections are connected, and then the condensation chambers 40+50 are fixed and the entire apparatus is assembled. The condensation chamber is fixed after the reaction chamber (including the intermediate connection) has been installed in the heating device 90. After assembling the device, a leak test is performed by exhausting air from the conduit 41. After confirming airtightness, exhaust air from the exhaust pipe 41,
Inert gas is filled into the entire apparatus through conduit 61 to a pressure slightly higher than atmospheric pressure. Next, a melt 80 of the sealing material is introduced into the pan 36 through the conduit 39 and solidified. Next, the heating furnace 90 is operated to heat the reaction chamber to melt the previously charged magnesium, and then a metal chloride is introduced from the conduit 61 to carry out the reaction to obtain a spongy metal and the by-produced chloride. Magnesium conduit 13
Emit more. After closing the closure means of the conduit 13, the heating device 70 of the intermediate connection 30 is then energized to heat the sealing pot and evaporate the sealing material therein. When the reaction chamber is evacuated again in this state and the reaction chamber is continued to be heated, both the magnesium chloride incorporated in the sponge-like metal and unreacted magnesium are vaporized and separated from the metal, and collected in the condensing cylinder 50. When the vacuum separation process is completed, the pressure inside the apparatus is restored with argon, and the sealing material is again introduced through the conduit 39 and solidified. Then, the condensing part is separated from the intermediate connecting part and taken out from the reaction chamber (including the intermediate connecting part) from the heating furnace, and after cooling, the discharge pipe 13 is cut and the produced sponge is taken out. Thus, one batch operation is completed. In the next operation, after the discharge pipe 13 is welded and attached again and the magnesium ingot is charged, the passage of the intermediate connection part has already been blocked, so assemble the device as is and repeat the previous operation. Example 1 A device substantially as shown in FIG. 2 was assembled. Its specifications are as follows. The reaction chamber and condensation chamber both have an external diameter of 700 mm and a height of 1760 mm.
mm, and the cylindrical body of the intermediate connecting part had a length (height) of 370 mm and an inner diameter of 185 mm. The reaction chamber was made of austenitic stainless steel (SUS304) and had a wall thickness of 16 mm. Paste magnesia cement on the inner surface to a thickness of about 5 mm, and add 120
NCK stamp paste manufactured by Nippon Carbon Co., Ltd. heated to 0.degree. C. was applied to a thickness of about 10 mm, hardened with a rammer, and heated with a torch to about 1000.degree. C. to form a carbon coating. A stainless steel plate with a thickness of 5 mm was used for the seal pot part, and the seal pot had an outer diameter of 108 mm and a height of 40 mm. The funnel-shaped body had an outer diameter of 68 mm and a height of 52 mm. The cooling chamber and condensing cylinder of the condensing chamber were made of 10 mm thick mild steel. Working Example 1 Titanium was produced according to the procedure described above. First, 350Kg of solid magnesium was charged into the reaction chamber.
Argon was introduced into the apparatus as an inert gas so that the internal pressure within the apparatus was higher than atmospheric pressure. Then, after blocking the passage in the intermediate connection using metallic magnesium as a sealing material, the reaction chamber was heated to 800-850 m
The charged magnesium is melted by heating to
1020 kg of titanium tetrachloride was introduced dropwise and reacted so as not to raise the temperature in the reaction chamber too much. After the reaction is complete, the entire apparatus is repressurized with argon, the produced magnesium chloride is discharged from the bottom discharge pipe, and the seal pot is operated as described above to open the passage in the intermediate connection. The reaction chamber was heated to 1000°C and the vacuum separation process was continued for about 30 hours to complete the vacuum separation. The molten magnesium is introduced into the seal pot again and solidified, the condensation chamber is removed, the reaction chamber (including the intermediate connection part) is taken out from the heating furnace, and after cooling, the reaction chamber is opened and the lower end of the reaction chamber is chlorinated. The magnesium discharge pipe was cut, and a rod pressed by a press was inserted and extruded to obtain 250 kg of titanium sponge. No major deformation was observed even after repeating this operation 100 times. The obtained sponge was free from carbon contamination. Comparative example For comparison, the reaction chamber has an inner cylinder, and both the reaction chamber and the inner cylinder are made of SUS410, the outer diameter of the reaction chamber is 700 mm, and the wall thickness is 700 mm.
Approximately 250 kg/batch of titanium was produced using a device with an outer diameter of 25 mm, an inner cylinder outer diameter of 600 mm, and a wall thickness of 10 mm, and the reaction chamber could be used approximately 50 times. The results of chemical analysis, extrusion pressure, and number of times the container can be used in Work Example 1 and Comparative Example are summarized in the following table.

Table 1 As can be seen, the extrusion pressure is greatly reduced in the containers of the present invention. Work Example 2 Zirconium was produced in the same manner as in Work Example 1. Approximately 50 kg of magnesium was charged into the reaction chamber. As the sealing material, metal magnesium was used as described above. Heat the reaction chamber to 800-850℃, about 210Kg
of zirconium tetrachloride was charged into the reaction chamber. Open the intermediate connection in the same manner as above, and then open the reaction chamber to 900 m
The vacuum separation process was continued for approximately 20 hours by heating to ~950°C. The following process is performed in the same way as for titanium, and approximately 80
Kg of sponge zirconium was obtained. This operation
Even after repeating the process 100 times, no significant deformation was observed in the reaction vessel. As explained in detail above, the present invention enables the reaction vessel to be manufactured from austenitic stainless steel, thereby providing the following advantages. 1. Compared to conventional equipment, the reaction rate is improved by increasing the reaction area, and the yield and quality are improved by reducing the contact area with the container wall per unit weight of the product. 2. It is possible to reduce the weight of the container per unit product amount and increase the number of times the container can be used. 3. Reduction in thermal energy required for heating, improvement in sensitivity to heating and cooling, and improvement in temperature estimation accuracy in temperature measurement from outside the container are achieved. 4. Since there is little resistance when mechanically removing the produced metal sponge lump from the container, the pressing force can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the concept of a known device forming the background of the present invention. FIG. 2 is a longitudinal sectional view showing an embodiment in which the present invention is applied to the apparatus shown in FIG. In these drawings, 10+20...reaction chamber, 40+50...condensation chamber, 30...middle connection section, 36...pan, 37...rotating shaft, 38...funnel-shaped body, 36+37+38...seal pot.

Claims (1)

[Claims] 1. In a reaction vessel for producing a high-melting-point, high-toughness metal by reduction of chloride with an active metal,
A reaction vessel characterized by being made of austenitic stainless steel and having its inner surface lined with carbon stamp material.