JPH0235015B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses group 4 metals such as Ti.Zr.Hf and Nb.
The present invention relates to a method for obtaining metals from chlorides of Group 5 metals such as Ta, and in particular to a method for efficiently performing a reduction step of these chlorides with metal Mg and a subsequent vacuum separation step.

In the case of Ti, for example, the above-mentioned metal is usually produced industrially by reduction of TiCl ₄ with molten Mg, that is, the so-called Kroll process. Many apparatus configurations have been proposed and put into practical use for carrying out this process. One of these is the reaction vessel and the vessel holding the molten metal Mgb, in order to facilitate the removal of the precipitate from the reaction vessel in which the formed metal precipitates in the form of a sponge, as well as the removal of unreacted Mg and MgCl ₂ present therein. There is a so-called inner/outer cylinder system which is composed of an outer cylinder and an inner cylinder which is placed inside the outer cylinder and mainly holds the generated metal.
Mg heated to high temperatures above ℃ and loaded inside
The reduction reaction proceeds by keeping the Mg molten and supplying TiCl ₄ onto this Mg. metal produced
Ti descends in the melt consisting of Mg and MgCl ₂ and is deposited on the bottom plate of the inner cylinder in the case of this inner/outer cylinder method, and the by-product MgCl ₂ becomes a metal due to the difference in density.
It replaces Mg and accumulates at the bottom of the outer cylinder. Therefore, Mg is always present in the liquid or gas phase on the surface of the melt that comes into contact with TiCl ₄ and the reduction reaction proceeds sequentially. During the reduction reaction, the MgCl ₂ accumulated at the bottom of the outer cylinder is intermittently or continuously discharged as a liquid phase out of the reaction system through a pipe leading from the bottom of the outer cylinder to the outside.
When the reaction progresses and the supply of Mg to the surface of the melt substantially stops, the supply of TiCl ₄ is stopped, the reduction process is terminated, and the next stage of vacuum separation (distillation) is started. Here, the by-product MgCl ₂ and unreacted metal Mg present together with the spongy metal Ti are melted and vaporized and removed from the Ti.

When producing metal Ti using the process described above,
In the reduction process, the by-product MgCl ₂ settles and the metal Mgb rises through the layer of produced metal Ti. Conventionally, this layer is formed on almost the entire cross section of the bottom plate and as the reaction progresses. As the thickness gradually increases, the resistance to the flow of the liquid increases, and as a result, the exchange rate of MgCl ₂ and Mg controls the reduction reaction itself, avoiding the drawback that the reaction rate gradually decreases. I couldn't help it. Furthermore, since Mg trapped in this spongy Ti is difficult to move, the utilization efficiency of Mg is inevitably low. On the other hand, in the vacuum separation process, when Mg and MgCl ₂ are evaporated and removed by external heating,
These vapors generated inside the deposit must pass through the thick layer of deposit through the pores or voids of the Ti sponge to the top surface or the bottom surface in contact with the bottom plate.
A considerable amount of time is required to achieve sufficient separation.

As described above, the present invention is characterized in that metal chloride,
For example, when performing the reduction reaction of TiCl ₄ with Mg, by securing a small space in the deposit that extends upward from the solid matter holding surface and allows the flow of liquid (and gas) in the center of the space, each of the above-mentioned drawbacks can be achieved. The gist of the invention is to reduce the metal chloride to metal by the molten Mg held in a tube structure that essentially has a closed structure. In order to remove inclusions by depositing on the inner lower holding surface and subjecting this formed metal to high temperature in a vacuum, a large number of small holes are formed in the side wall near the center (axis) of the holding surface within this cylindrical structure. After placing a hollow cylindrical body in the shape of a cone or truncated cone, molten Mg
A path for the molten liquid is provided in the center of the formed metal deposited by the reaction between the metal chloride and the metal chloride, and after depositing a predetermined amount of the formed metal within this cylindrical structure,
The generated metal and inclusions mainly consisting of Mg and MgCl ₂ are subjected to high temperature in vacuum, and the Mg and MgCl ₂ are transferred to the lower surface and through the small holes of the hollow cylindrical body as gas and liquid phases to form the generated metal. The gist of this invention is a method for obtaining metals from metal chlorides, which is characterized by separating them from metal chlorides.

In the present invention, the small space is provided by placing a hollow cylinder having a large number of small holes on the side surface on the bottom plate. The cross section of the hollow cylinder is preferably a conical shape or a truncated conical shape, particularly tapered at the top, in order to facilitate removal of the cylindrical body after metal refining by vacuum evaporation. The lower end of the hollow tube is at least partially open. Although it is preferable that the top is also closed, it may have some openings. The size of the hollow cylinder internal space is sufficient as long as it allows movement of the liquid phase and the gas phase, and a cylindrical shape with an inner diameter of about 10 cm is sufficiently effective. Although the length of the space is preferably large, it is preferable that the space does not extend above the surface of molten Mg at the start of the reduction reaction. The small holes can be provided in various shapes, but in any case, it is advantageous to make them as large as possible without allowing the produced Ti to pass through them, in terms of Mg/MgCl ₂ exchange efficiency and separation efficiency during vacuum separation. Specifically, a circular hole with a diameter of 50 mm or less on the side surface is sufficiently advantageous. These small holes are optimally placed near the tip of the hollow cylinder or at the deepest part of the deposit. Such hollow tubes are made of ordinary stainless steel, structural steel or
It can be made of various materials such as Ti.

In the case of the above-mentioned cylindrical structure consisting of an inner and outer cylinder, the present invention is implemented using separate apparatuses for the reduction process and the vacuum separation process (for example, Japanese Patent Publication No. 33-2104 and No. 48
-34646) is used, and the inner cylinder holding the deposits is transferred to a vacuum separation device after the completion of the reduction process, as well as the method described in Japanese Patent Publication No. 55-36254, in which both processes are common. It is also possible to use a configuration in which the inner cylinder is not moved between the two steps, and the inner cylinder is not moved between the two steps.

The advantages of the present invention become particularly noticeable when the above-mentioned cylindrical structure consisting of an inner and outer cylinder is used to promote vaporization from the bottom surface of the deposit. Even in the case of a single-tube configuration as shown in Figure 1, the mechanism of the deposition of Ti formed in the reduction process and the rise of Mg due to the fall of MgCl ₂ is the same as above, and the mechanism of the rise of Mg due to the fall of MgCl 2 in the reduction process is the same as above. A certain effect can be expected because the surrounding voids made possible to remove inclusions from the lower surface of the deposit. In this case, the hollow cylinder is a false bottom provided in the center of the container.
It is convenient to install it on top.

Next, the present invention will be explained with reference to the drawings. FIG. 1 is a longitudinal sectional view schematically showing a reduction apparatus suitable for carrying out the present invention, and FIG. 2 is a schematic longitudinal sectional view of a vacuum separation apparatus. In the figure, an outer cylinder 1 for isolating the reaction system from the outside world is an essentially cylindrical container whose lower end is closed and whose upper end is sealed by a removable lid 2, and has an iron shell 3 disposed around it. It is heated by a furnace 4 having. Although it is not essential, the space between the outer cylinder 1 and the furnace 4 can be
56-50896 (Japanese Unexamined Patent Publication No. 60-5653), the load on the outer cylinder can be reduced if the pressure can be adjusted using an inert gas as a closed structure. On the other hand, the upper part of the inner cylinder 5 is connected to the lid 2 in various ways, but in this case, it is advantageous to configure the inner cylinder 5 to be detachable by tightening bolts or the like. Such engagement is described, for example, in Japanese Patent Application No. 1-18134. The lid 2 has a separable central part 6 in this example.
and an outer peripheral part 7, and metal cases 8 and 9 filled with a heat insulating material are attached to the lower surface of each part. A TiCl ₄ supply pipe 1 is inserted through the lid 2 constructed in this way.
0, exhaust pipe 11 and inert gas introduction pipe 12
However, if necessary, the molten Mg introduction pipe 13 can be connected to the inner cylinder 5.
extends inward. A bottom plate 14 in the shape of a rooster is attached to the lower part of the inner cylinder supported by a piece for holding solid matter, and a hollow cylinder 15 whose lower end is open and whose upper end is closed is placed near the center of the bottom plate. This hollow cylinder having a large number of small holes in the side wall can be made of stainless steel such as SUS410, for example, and can be constructed in the shape of a cone or a truncated cone. These hollow cylinders can be formed with a cross section at the bottom somewhat larger than the other parts so as not to fall during operation, and/or can be welded to the bottom plate 14 at one to several places. As will be described later, it is advantageous to provide a pipe 16 extending from the bottom of the outer cylinder 1 to the outside of the furnace 4 in order to discharge MgCl ₂ in liquid form. Such a reduction device has a bottom plate 1
It can be operated in the same manner as similar conventional devices, except that a hollow cylinder having a length determined based on the amount of molten Mg held when attaching No. 4 to the inner cylinder is installed. That is, the inner cylinder 5 with the lid 2 attached is fixed in the outer cylinder 1, and after creating an inert gas atmosphere in the cylinder structure consisting of both cylinders or the inside of the reaction vessel, metal Mg is molten and held, and TiCl ₄ is applied to the surface of this bath. Supplied as liquid or gas phase. Ti17 generated by the reaction is deposited in a spongy manner on the bottom plate 14 around the hollow cylinder, and the by-products are
MgCl ₂ 18 descends to the bottom of the outer cylinder through the voids of the sponge and the hollow cylinder space, and pushes up Mgb 19 instead. When the amount of Mg available on the surface of the molten bath decreases and the internal pressure begins to rise, the supply of TiCl ₄ is stopped and the reduction process is terminated. In order to efficiently utilize the space inside the inner cylinder,
Furthermore, in order to reduce the amount removed in the next vacuum separation step, MgCl ₂ is discharged as a molten liquid either continuously or intermittently during the reduction step, or through the pipe 16 after the end of the step. The generated Ti sponge is interposed
In order to remove MgCl ₂ and Mg, it is transferred to a vacuum separation process while being held in the inner cylinder after cooling. The device used for this is not a requirement of the present invention, and various configurations may be used, but in the case of the reduction device having the configuration shown in FIG. 1, the configuration shown in FIG. 2 can be advantageously used. That is, this device basically has an outer cylinder 20 consisting of a separable upper and lower part, a cooling water cannula 21 attached to the outer periphery of the upper part, and a furnace 23 surrounded by an iron shell 22 that heats the lower part from the outer periphery. The inner cylinder 24 from the above-mentioned reduction process is placed at the bottom of the outer cylinder of the vacuum separation device from which the upper part of the outer cylinder 20 has been removed, and a heat shielding device 25 made of, for example, a ring-shaped steel plate group and a conical plate group is placed on top of this inner cylinder 24. is placed. Above this, an empty inner cylinder 26 having the same configuration as that used in the reduction process is connected to the upper part of the outer cylinder, which has been previously installed via a lid 27 by tightening bolts in the same way. In this case, an exhaust pipe 28 is fitted into the center of the lid 27 in place of the center of the reducing device by the same means. A baffle plate 29 is provided at the bottom of the connection end. In such an assembly, after the pressure is reduced to a high degree of vacuum, the furnace 23
While heating the lower part of the outer cylinder, the upper part is heated by the water mantle 21.
It is cooled by the operation of In this case, the molten and vaporized Mg and MgCl ₂ pass through the voids in the Ti sponge to the outside through the top of the deposit and the perforations in the bottom plate 30, and in the present invention, exit through the space in the central hollow cylinder 31, so it is extremely Efficient separation can be obtained.

As is clear from the above, a feature of the present invention is that a small space for liquid passage and ventilation is provided in the produced metal in the process of producing a sponge-like metal and separating inclusions. Although the configurations of both devices shown here are themselves significantly improved over conventional configurations, they are shown here for convenience and explanation purposes only. Therefore, of course, various other configurations are possible.

EXAMPLE An apparatus essentially shown in FIGS. 1 and 2 was used. The outer cylinder and inner cylinder, which are arranged almost coaxially in the reduction device, have an inner diameter of 16 m and 1.5 m, respectively, a wall thickness of 32 mm and 16 mm (excluding the upper end), and a total length of the outer cylinder of 5 m.
The inner cylinder is made of stainless steel with an effective length (the space located inside the furnace) of 3.7 m, and the distance between the bottom plate and the bottom of the outer cylinder is 0.5 m.
It is m. Bottom outer diameter 40 on the bottom plate with numerous perforations
A conical hollow cylinder made of stainless steel (SUS410) with a wall thickness of 9 mm and a height of 1.5 m was placed. A number of circular holes with a diameter of 35 mm are provided on the side surface of this hollow cylinder. This bottom plate is attached to the inner cylinder via the frame, while the upper end is attached to the SS using high-tensile steel bolts.
Connected to a lid made of steel and consisting of a separable center and outer periphery. These were installed in an electric furnace with a total height of 5.5 m and an inner diameter of 2.1 m. On the other hand, regarding the separation device, the outer cylinder has an inner diameter of 1.6 m and a wall thickness of 32 mm.
The length is 5 m (lower part) and 2.85 m (upper part) made of stainless steel.The upper part, which is used as a cooling cylinder, has a water cooling jacket around the outer circumference, and the lower part is installed in the furnace.

After deaerating the inside of the reduction cylinder, fill it with argon.
It was then heated to 800°C in a furnace. 7 tons
After charging Mg in a molten state into the outer cylinder from the inlet tube and raising the temperature of the inner cylinder to about 900°C, a reaction operation was carried out by supplying liquid TiCl ₄ at a rate of 400 kg/hour. The top of each bolt was cooled with water while the by-product MgCl ₂ was intermittently discharged from the bottom of the outer cylinder for a total of about 50 hours.
After charging 20 tons, the injection of TiCl ₄ was stopped. After most of the remaining MgCl ₂ was discharged, the inner cylinder was sufficiently cooled. During this time, the upper part of the outer cylinder of the separation apparatus was assembled in preparation for the next vacuum separation step. First, a similar outer periphery of the lid was attached to the upper part of the outer cylinder, which was engaged with another empty inner cylinder having the same structure as the inner cylinder, and the connecting end of the exhaust pipe was airtightly attached to the center part. A patent application filed by the present patent applicant in 1982-
56041 (Japanese Unexamined Patent Publication No. 58-174530), the sample was placed in the bottom of the outer cylinder of a vacuum separator, a heat shield was placed, and the upper part of the outer cylinder was further placed and fixed. With this configuration, a vacuum was drawn through the exhaust pipe at the top, and the lower part was heated to about 1000°C, while the upper part was cooled with water, and the separation process was completed in 50 hours. In this process, Mg and MgCl ₂ from below were attached to the inner cylinder attached to the upper part of the outer cylinder, so this was stored in the outer cylinder of the reduction device for use. As described above, in carrying out the method of the present invention, the injection of 20 tons of TiCl ₄ can be completed in 50 hours, and the reaction is carried out at a Mg utilization rate of 73%.

On the other hand, in an example of an operation using the same configuration but without providing the small space for ventilation and liquid passage, which is a feature of the present invention, for the first approximately 40 hours in the reduction process,
It was possible to inject TiCl ₄ at a rate of 340 kg/hour, but after that the speed of Mg reaching the melt surface became smaller, so the injection speed had to be gradually reduced, and in the end, 18 tons of TiCl ₄ were injected. It took 65 hours. Also, the utilization rate of Mg at this time was approximately 68%.

For the sake of convenience, the above operation has been explained for the case where the reduction process and the vacuum separation process are performed in independent equipment, but for example, as described in Japanese Patent Publication No. 55-36254, both processes are carried out in a common furnace and outer cylinder. Good results have also been obtained with the configuration carried out in a single-tube configuration, and it can also be applied to a reaction vessel with a single cylinder configuration.

As detailed above, in the present invention, a small space for liquid passage and ventilation is provided in the deposit mainly made of Ti sponge held in the cylindrical structure constituting the reaction vessel, extending upward from the surface holding the deposit. (1) Since the discharge of MgCl ₂ , a byproduct in the reduction process, and the supply of Mg to the reaction surface or the melt surface are carried out efficiently through this small space, the deposited Ti The path through the sponge, which has a high resistance, is shortened compared to the conventional configuration in which the process is carried out only through the voids in the sponge, and the MgCl ₂
It has become easier to discharge Mg, and it has become possible to increase the usage rate of Mg.

(2) Separation from spongy metal during vacuum separation process
The easier removal of Mgb and MgCl ₂ allows for increased amounts of sponge metal to be deposited within the tube configuration.

(3) Using a vacuum separation device in which the heating part is located below and the cooling part is located above in the inner/outer cylinder method,
Furthermore, when the inner cylinder from the reduction process is stored, if the lower surface of the bottom plate communicates with the upper surface of the deposit through the outer cylinder space, Mg and MgCl ₂ are released not only from the upper and lower surfaces of the deposit, but also from the small Since the separation is also carried out from inside the sponge via the space, the time required for the separation operation can be shortened.

It offers advantages such as:

[Brief explanation of drawings]

FIGS. 1 and 2 are vertical sectional views schematically showing a reduction apparatus and a vacuum separation apparatus suitable for carrying out the method of the present invention. In the figures, reference numbers indicate the following members. 1... Outer cylinder (reducing device); 2... Lid; 3... Iron shell; 4... Furnace; 5... Inner cylinder; 6, 7... Lid center and outer periphery; 8, 9... Heat insulation Material case; 10...
TiCl ₄ supply pipe; 11... Exhaust pipe; 12... Inert gas introduction pipe; 13... Molten Mg introduction pipe; 14...
Bottom plate; 15...Hollow cylinder; 16...MgCl ₂ discharge pipe;
17... Ti sponge; 18... MgCl ₂ ; 19...
...Mg; 20... Outer cylinder (vacuum separation device); 21...
... Water mantle; 22 ... Iron shell; 23 ... Furnace; 24 ... Inner cylinder to be treated; 25 ... Heat shield; 26 ... Inner cylinder (empty); 27 ... Lid; 28 ... Exhaust pipe; 29... Baffle plate; 30... Bottom plate; 31... Hollow tube.

Claims (1)

[Claims] 1. A metal chloride is supplied into a tube structure having an essentially sealed structure, and the molten Mg held therein reduces it to metal, which is deposited on the holding surface at the bottom of the tube structure, and further, this generated metal is When removing inclusions by subjecting the tube to high temperature in a vacuum, a conical or truncated conical hollow tube with many small holes in the side wall was placed near the center (axis) of the holding surface within this tube structure. A path for the molten liquid is provided in the center of the formed metal that is deposited by the reaction between the molten Mg and the metal chloride, and after a predetermined amount of formed metal is deposited within this cylinder structure, the formed metal and mainly Mg are deposited. as well as
The inclusions made of MgCl ₂ are subjected to high temperature in vacuum, and the Mg and MgCl ₂ are separated from the formed metal as a gas phase and a liquid phase through the lower surface and the small holes of the hollow cylindrical body. A method for obtaining metals from metal chlorides.