JP2009197277A - MOLTEN SALT ELECTROLYSIS METHOD, ELECTROLYTIC CELL, AND METHOD FOR PRODUCING Ti BY USING THE SAME - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolysis method by which the stress caused by a molten salt and applied to an isolation body is reduced, in an electrolytic cell having the isolation body therein. <P>SOLUTION: The inside of a vessel 11 of an electrolytic cell is partitioned into an anode chamber 21 including an anode 12 and a cathode chamber 22 including a cathode 13 by a diaphragm 18 being an isolation body. The anode chamber 21 and the cathode chamber 22 are each provided with an injection port 15 and a discharge port 17 for a molten salt. Then, the stresses from the anode chamber 21 side and the cathode chamber side 22 are applied to the diaphragm 18 in such a manner that the stresses cancel each other by the pressure drop generated by flowing the molten salt through the anode chamber 21 and the cathode chamber 22. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a molten salt electrolysis method capable of reducing stress applied to a separator disposed inside an electrolytic cell, an electrolytic cell used therefor, and a Ti production method using the method.

As an industrial method for producing metal Ti, a crawl method in which TiCl ₄ is reduced with Mg is generally used. According to this method, a high-purity product can be produced. However, since the generated Ti powder settles in an aggregated state and is difficult to recover outside the reaction vessel, the operation must be performed in a batch mode. In addition, since TiCl ₄ is supplied in liquid form from above to the liquid surface of the molten Mg liquid in the reaction vessel, and the reaction is performed only near the liquid surface of the molten Mg liquid, avoiding a decrease in the utilization efficiency of TiCl ₄ , In order to avoid local exotherm accompanying the reaction, the feed rate of TiCl ₄ is limited. As a result, the manufacturing cost increases and the product price becomes very high.

Therefore, many researches and developments have been made on methods for producing metal Ti other than the crawl method. For example, in Patent Document 1, a molten salt of CaCl ₂ is held in a reaction vessel, a metallic Ca powder is supplied into the molten salt from above, and Ca is dissolved in the molten salt, and TiCl ₄ is dissolved from below. A method of supplying gas and reacting dissolved Ca and TiCl ₄ in a molten salt of CaCl ₂ is described. However, metallic Ca powder is extremely expensive, and in addition, highly reactive Ca is very difficult to handle, and this method cannot be established as an industrial metallic Ti production method.

Therefore, the inventors of the present invention need to reduce TiCl ₄ with Ca in order to industrially establish a method for producing metal Ti by Ca reduction, and economically use Ca in molten salt consumed in the reduction reaction. In addition to utilizing Ca produced by electrolysis of molten CaCl ₂ , a method of circulating and using this Ca, ie, the “OYIK method (Oic method)” was proposed (Patent Documents 2 and 3). reference).

Patent Document 2 describes a method in which Ca is generated and replenished by electrolysis, and molten CaCl ₂ with an increased Ca concentration is introduced into a reaction vessel and used to generate Ti particles by Ca reduction. Furthermore, a method of effectively suppressing back reaction accompanying electrolysis by using an alloy electrode (for example, Mg—Ca electrode) as a cathode is shown. Back reaction refers to the reaction between Ca in the molten salt and Cl ₂ generated by electrolysis when the molten salt from which Ti has been separated in the separation step is returned to the electrolytic cell, and back reaction occurs. , Current efficiency decreases.

The manufacturing method of Ti described in Patent Document 4 is based on the OYIK method. In the electrolytic cell, the molten salt is electrolyzed while flowing in one direction near the cathode (cathode) surface, The molten salt with an increased Ca concentration is recovered on the molten salt discharge side, and the molten salt is used for the reduction of TiCl ₄ . In this method, since the molten salt with an increased Ca concentration can be taken out effectively, the efficiency of the reduction reaction of TiCl ₄ can be improved and Ti can be produced efficiently.

U.S. Pat. No. 4,820,339 JP 2005-133195 A JP 2005-133196 A JP 2007-63585 A

  In the Ti production method described in Patent Document 4, a molten salt is contained in a cathode chamber, which is a space including a cathode, among the spaces separated by a diaphragm disposed between the anode and the cathode inside the electrolytic cell. The molten salt flow is formed in one direction upward or downward. On the other hand, the molten salt corresponding to the amount reduced by electrolysis is only supplied to the anode chamber, which is a space including the anode, and the molten salt is almost stationary.

  In an electrolytic cell, in order to reduce electric power required for electrolysis and improve current efficiency, it is desirable to reduce the electrical resistance of the molten salt by narrowing the distance between the cathode and the anode. Therefore, it is desirable to narrow the width of the anode chamber and the cathode chamber, that is, to reduce the cross-sectional areas of the anode chamber and the cathode chamber when cut perpendicular to the longitudinal direction. However, if the cross-sectional area of the cathode chamber is reduced, the pressure loss in the cathode chamber is increased. Therefore, in order to ensure a necessary flow rate of the molten salt, it is necessary to apply a certain pressure when injecting the molten salt.

  Therefore, a pressure difference occurs between the inlet and outlet of the molten salt in the cathode chamber, while the molten salt is almost stationary in the anode chamber, so there is no pressure difference at both ends due to pressure loss as in the cathode chamber. . Therefore, in the electrolytic cell, the pressure on the cathode chamber side is higher than that on the anode chamber side in the vicinity of the molten salt inlet.

As a result, Ca generated by electrolysis in the cathode chamber flows into the anode chamber through the diaphragm, and reacts with Cl ₂ generated in the anode chamber to cause a back reaction, resulting in a decrease in current efficiency. Furthermore, stress is applied to the diaphragm due to the above-described pressure difference between the cathode chamber side and the anode chamber side, and there is a risk that the life of the diaphragm will be reduced or damaged. However, if the thickness is increased in order to improve the strength of the diaphragm, the distance between the cathode and the anode must be increased, which also decreases the current efficiency.

  An object of the present invention is to reduce stress applied to a separator such as a diaphragm, reduce the possibility of breakage even when the separator is thin, improve current efficiency, and have high durability and high Ca concentration efficiency. It is to provide an electrolytic cell.

  In order to solve the above-mentioned problems, the present inventors examined the pressure caused by the molten salt in the electrolytic cell. As a result, the molten salt in the anode chamber is caused to flow in the same direction as the molten salt in the cathode chamber so that the pressure at the inlet of the anode chamber is equal to or higher than the pressure at the inlet of the cathode chamber, so that the pressure loss also occurs in the anode chamber. The idea was to cancel the stress from the cathode side applied to the separator by the stress from the anode side. As a result, the risk of breakage of the separator can be reduced and the separator can be thinned, so that the current efficiency can be improved.

  The present invention has been made on the basis of such knowledge, and the gist of the present invention is the following (1) molten salt electrolysis method, (2) electrolytic cell below and (3) Ti production method below. .

  (1) having an anode, a cathode facing the anode, a separator disposed between the anode and the cathode, an anode chamber having the anode, separated by the separator, and the cathode A cathode chamber, having an inlet for molten salt at one end of the anode chamber and the cathode chamber, respectively, and an outlet for the molten salt at the other end of the anode chamber and the cathode chamber, respectively, In the electrolytic cell for electrolysis, the molten salt flows from the inlets of the anode chamber and the cathode chamber in the same direction in the anode chamber and the cathode chamber, and the pressure at the inlet of the anode chamber is the cathode chamber. The molten salt electrolysis method is characterized by injecting so as to be equal to or higher than the pressure at the injection port.

  In the molten salt electrolysis method described in (1) above, it is desirable to inject the molten salt so that the pressure at the inlet of the anode chamber is larger than the pressure at the inlet of the cathode chamber. If the difference between the pressure at the inlet of the anode chamber and the pressure at the inlet of the cathode chamber is too large, the separator may be damaged. Therefore, the pressure is preferably 0 MPa or more and 0.01 MPa or less. In order to prevent the molten salt from flowing into the chamber, 0.001 MPa or more and 0.01 MPa or less is more desirable. In addition, it is desirable that the flow direction of the molten salt is vertically upward from the viewpoint of using the upward driving force by the gas generated by electrolysis of the molten salt.

In the molten salt electrolysis method described in (1) above, when the molten salt contains CaCl ₂ , Ca generated by electrolysis can be dissolved in the molten salt. It can be used for the production of metallic Ti by reacting with TiCl ₄ .

Ca precipitated when the Ca concentration exceeds the saturation concentration is more active than Ca dissolved in the molten salt, and damages the electrolytic cell, so the Ca concentration in the molten salt in the cathode chamber rising by electrolysis is less than the saturation concentration. It is desirable to inject the molten salt so that Further, since Cl ₂ is generated by electrolysis of CaCl _{2 in} the anode chamber, it is desirable that Ca is not dissolved in the molten salt injected into the anode chamber for the purpose of preventing back reaction.

  (2) An electrolytic cell that has an anode and a cathode facing the anode, and electrolyzes the molten salt, and is separated by the separator disposed between the anode and the cathode An anode chamber having the anode and a cathode chamber having the cathode, an inlet for molten salt at one end of the anode chamber and the cathode chamber, and the molten salt at the other end of the anode chamber and the cathode chamber, respectively. An electrolytic cell characterized in that the molten salt flows in the same direction in the anode chamber and the cathode chamber.

  In the molten salt electrolysis method according to (1) and the electrolytic cell according to (2), it is desirable that the separator is a diaphragm made of a metal sintered body.

(3) A first molten salt containing CaCl ₂ and dissolved therein is introduced into a reaction vessel, and TiCl ₄ is reduced by Ca in the molten salt to generate Ti particles in the first molten salt. A reduction step of separating the Ti particles from the first molten salt, and generating Ca by electrolyzing the first molten salt to produce a Ca concentration in the first molten salt. In the manufacturing method of Ti which has an electrolysis process to raise, in the electrolysis process, the electrolysis method of the molten salt according to any one of claims 1 to 5 and 7 is applied, and the first melt A method for producing Ti, characterized in that a salt is injected and a second molten salt containing CaCl ₂ and not dissolving Ca is injected into the anode chamber.

  According to the electrolysis method and the electrolytic cell of the present invention, in addition to the stress from the cathode side applied to the separator by the molten salt, the stress from the anode side in the opposite direction is also generated, and the stress applied to the separator is reduced. The risk of breakage of the separator can be reduced, and the current efficiency can be improved because the separator can be thinned.

  Moreover, according to the Ti manufacturing method of the present invention, the Ca concentration can be increased efficiently in the electrolysis step, and therefore the Ti particle generation efficiency in the reduction step can be improved.

  First, the electrolytic method of the present invention described in (1) and the electrolytic cell of the present invention described in (2) will be described.

  The electrolysis method of the present invention includes an anode, a cathode facing the anode, a separator disposed between the anode and the cathode, and an anode chamber having the anode separated by the separator. A cathode chamber having the cathode, and having an inlet for molten salt at one end of the anode chamber and the cathode chamber, respectively, and an outlet for the molten salt at the other end of the anode chamber and the cathode chamber, In the electrolytic cell for electrolyzing the molten salt, the molten salt flows from the inlets of the anode chamber and the cathode chamber in the same direction in the anode chamber and the cathode chamber, and the pressure at the inlet of the anode chamber Is injected so as to be equal to or higher than the pressure at the injection port of the cathode chamber.

FIG. 1 is a diagram showing a configuration example of an electrolytic cell of the present invention. The electrolytic cell 10 includes a long cylindrical electrolytic cell container 11 that holds a molten salt containing CaCl ₂ , a cylindrical anode 12 that is disposed inside the electrolytic cell container 11 along the longitudinal direction, and an anode 12 is arranged so that the longitudinal direction is parallel to the vertical direction.

  A bottom plate 14 having an inlet 15 through which molten salt is injected is provided at the lower end of the electrolytic cell container 11, and a lid 16 having an outlet 17 through which molten salt is discharged is provided at the upper end. The inner surface of the anode 12 and the surface of the cathode 13 are opposed to each other, and the anode 12 and the cathode 13 are both disposed so that the longitudinal direction thereof is parallel to the vertical direction, and the separator that isolates the anode 12 and the cathode 13 from each other. A diaphragm 18 is disposed between the anode 12 and the cathode 13. The diaphragm 18 suppresses the passage of Ca generated by electrolysis of molten salt in the vicinity of the cathode 13 to the anode 12 side.

  As described above, the inside of the electrolytic cell container 11 is separated into two spaces by the diaphragm 18, and a space including the anode 12 is referred to as an anode chamber 21, and a space including the cathode 13 is referred to as a cathode chamber 22. The injection port 15 provided in the bottom plate 14 includes an anode side injection port 15 a through which molten salt is injected into the anode chamber 21 and a cathode side injection port 15 b into which the molten salt is injected into the cathode chamber 22. Similarly, the discharge port 17 provided in the lid 16 includes an anode side discharge port 17 a through which the molten salt is discharged from the anode chamber 21 and a cathode side discharge port 17 b through which the molten salt is discharged from the cathode chamber 22. An anode side pump 23 and a cathode side pump 24 for injecting molten salt at a predetermined pressure are disposed at the anode side inlet 15a and the cathode side inlet 15b, respectively. The anode-side discharge port 17 a is connected to the anode-side injection port 15 a via the anode-side pump 23 and the pipe 25.

In the electrolytic cell 10 configured as described above, CaCl ₂ contained in the molten salt is electrolyzed while continuously or intermittently injecting the molten salt into the anode chamber 21 and the cathode chamber 22 of the electrolytic cell container 11. As a result, Ca is generated in the cathode chamber 22 to increase the Ca concentration in the molten salt, and Cl ₂ is generated in the anode chamber 21. However, since the molten salt in the anode chamber 21 and the molten salt in the cathode chamber 22 are not in direct contact, back reaction due to re-reaction of Ca and Cl ₂ can be prevented.

  By injecting molten salt into the anode chamber 21 and the cathode chamber 22 continuously or intermittently, a molten salt flow directed upward can be formed in both the anode chamber 21 and the cathode chamber 22. This molten salt flow causes pressure loss in both the anode chamber 21 and the cathode chamber 22, so that the stress from the anode chamber 21 side and the stress from the anode chamber 21 side in the opposite direction cancel each other in the diaphragm 18. Therefore, the stress applied to the diaphragm 18 is reduced. And the magnitude | size of the pressure loss which generate | occur | produces in the anode chamber 21 and the cathode chamber 22 can be adjusted by adjusting the injection amount of molten salt, and the stress concerning the diaphragm 18 can also be adjusted.

  When injecting the molten salt, it is desirable that the pressure at the anode side inlet 15a be equal to or higher than the pressure at the cathode side inlet 15b. The differential pressure obtained by subtracting the pressure at the cathode side injection port 15b from the pressure at the anode side injection port 15a is preferably 0 MPa or more and 0.01 MPa or less, and more preferably 0.001 MPa or more and 0.01 MPa or less. By injecting the molten salt in this way, the stress caused by the molten salt from the anode chamber 21 side and the cathode chamber 22 side to the diaphragm 18 can be further reduced. Thereby, since there is less fear of breakage due to the stress of the molten salt, the diaphragm 18 can be thinned, current efficiency can be improved, and Ca generation efficiency can be improved. Further, since the pressure at the anode side inlet 15a is made higher than the pressure at the cathode side inlet 15b, the molten salt can be sufficiently prevented from flowing into the anode chamber 21 from the cathode chamber 22, so that the current efficiency is also improved. And the Ca production efficiency can be improved.

In the electrolytic cell 10, a tank 26 for supplying CaCl ₂ may be provided in the middle of the pipe 25 connecting the anode side discharge port 17a and the anode side injection port 15a. This makes it possible to replenish CaCl ₂ that has been reduced by electrolysis.

As the diaphragm 18, a porous ceramic containing yttria (Y ₂ O ₃ ) or a porous metal sintered body can be used.

  FIG. 2 is a diagram showing a configuration example of a diaphragm made of ceramics. The metal sintered body is a plate-like material produced by sintering two metal nets and metal fibers sandwiched between them, and is flexible, weldable, and has a large degree of freedom. large. Therefore, the diaphragm 18 formed by welding the plate-shaped metal sintered body into a cylindrical shape can be enlarged. On the other hand, when the diaphragm 18 is made of ceramics, it is impossible to manufacture a large integrated body like a metal sintered body. Therefore, the diaphragm 18 is manufactured by combining a plurality of parts.

  For example, FIG. 2 (a) is a combination of a plurality of diaphragm parts 18a provided with steps 18b and 18c at the edges of both ends of an annular diaphragm part 18a made of ceramics. In FIG. 2B, a spacer 18d provided with a step 18e to be combined with the step 18b of the diaphragm part 18a is disposed between the diaphragm parts 18a provided with a step at both ends. The spacer 18d is desirably formed of a material having strength higher than that of the ceramic forming the diaphragm component 18a.

  As a separator that separates the anode 12 and the cathode 13, a partition configured to allow a part of the molten salt to flow therethrough may be used instead of the diaphragm 18. The partition does not allow molten salt such as Ca and chlorine ions as well as metal Ca, but by providing a slit or a hole through which molten salt can pass in a part of the partition, electrolysis is possible. It is possible to limit the passage to some extent and suppress back reaction.

Although the flow direction of the molten salt is vertically upward in FIG. 1, it may be downward. However, in the anode chamber 21, an upward driving force is generated by the Cl ₂ gas generated in the molten salt. From the viewpoint of using this driving force, it is desirable that the flow direction of the molten salt is vertically upward.

Furthermore, the metal Ca deposited when the electrolysis proceeds in the cathode chamber 22 and the Ca concentration in the molten salt becomes supersaturated has a lower specific gravity than CaCl ₂ and floats above the molten salt. Also from the viewpoint of increasing the recovery efficiency, it is desirable that the flow direction of the molten salt is vertically upward.

  Further, it is desirable that the molten salt injected into the cathode chamber 22 is in such an amount that the Ca concentration produced in the cathode chamber 22 by electrolysis is less than the saturation concentration even when it is completely dissolved. When the Ca concentration exceeds the saturation concentration and becomes supersaturated, Ca that cannot be completely dissolved is precipitated in a finely dispersed state in the molten salt, and the precipitated Ca is more active than Ca dissolved in the molten salt. This is because it corrodes the diaphragm 18 containing, thereby reducing the life of the electrolytic cell 10.

  Next, the Ti manufacturing method described in (3) will be described.

FIG. 3 is a diagram showing an example of steps in carrying out the Ti manufacturing method of the present invention. As shown in FIG. 3, in this Ti manufacturing process, Ca in a molten salt containing CaCl ₂ and dissolved therein is reacted with TiCl ₄ to generate Ti particles that are particles of metallic Ti in the molten salt. Reduction step 31, separation step 32 for separating Ti particles generated in the molten salt from the molten salt, and increasing the Ca concentration by electrolyzing the molten salt whose Ca concentration has decreased with the generation of Ti particles An electrolysis process. In the Ti production method of the present invention, in order to apply the above-described electrolysis method of the present invention in this electrolysis step, an electrolytic cell 10 used for carrying out this electrolysis method is incorporated in FIG.

The molten salt whose Ca concentration is increased by electrolysis of CaCl _{2 in} the electrolytic cell 10 is discharged from the cathode side outlet 17 b of the electrolytic cell 10 and transferred to the reduction step 31.

In the reduction step 31, when TiCl ₄ gas is reacted with Ca in the molten salt having an increased Ca concentration, Ti particles are generated in the molten salt by the reduction reaction. When the reduction reaction in the molten salt proceeds, Ca in the molten salt is consumed, and CaCl ₂ is generated together with Ti particles.

  The Ti particles generated in the reduction step 31 are transferred to the separation step 32 together with the molten salt, and the Ti particles are separated from the molten salt. For the separation, a high-temperature decanter or a hydrocyclone can be used.

  The Ti particles separated from the molten salt in the separation step 32 are heated and dissolved in the dissolution step 33 to form an ingot 34.

  On the other hand, the molten salt having a reduced Ca concentration from which the Ti particles have been separated is transferred to the electrolysis process and injected from the cathode side injection port 15 b of the electrolytic cell 10. Then, the Ca concentration is increased again by electrolysis and transferred to the reduction step 31.

  By configuring the Ti production process as shown in FIG. 4, the Ca concentration can be increased efficiently in the electrolysis process, so the Ti particle production efficiency and the Ti ingot production efficiency in the reduction process are improved. be able to.

  In order to confirm the effect of the molten salt electrolysis method of the present invention, the following molten salt electrolysis test was conducted and the results were evaluated.

1. Molten salt electrolysis conditions The molten salt was electrolyzed using the apparatus shown in FIG. The electrolysis conditions were as shown in Table 1. The differential pressure in Table 1 is a value obtained by subtracting the pressure at the cathode side inlet from the pressure at the anode side inlet. The anode used was carbon having an inner diameter of 100 mm, the cathode used was Fe having a diameter of 10 mm, and the diaphragm was used having an inner diameter of 50 mm and a thickness of 5 mm. The temperature of the molten salt was 850 ° C., and the cathode current density was 1.0 to 20 A / cm ² . The flow rate of the molten salt in the cathode chamber was 10 L / min, and the pressure at the cathode side inlet was 0.015 MPa.

  In Examples 1 and 4 of the present invention, the pressure at the anode side inlet and the pressure at the cathode side inlet are the same, and in Examples 2 and 3, the differential pressure is the value in the table. The flow rate of the molten salt in the anode chamber was adjusted. In the comparative example, since the molten salt did not flow into the anode chamber, the flow rate of the molten salt in the anode chamber was set to zero. In the comparative example, although the flow rate of the molten salt in the anode chamber was 0, the pressure at the anode side inlet was generated because the hydrostatic pressure corresponding to the depth of the molten salt was generated because the inlet was below. It is.

2. Test Results The electrolysis performed under the above conditions was evaluated using the current efficiency as an evaluation index. The current efficiency is shown together with the electrolysis conditions injected in Table 1.

  As shown in Table 1, in all of Examples 1 to 4 of the present invention, the current efficiency was 88% or more, which was a good value compared with 75% of the comparative example. In Examples 2 and 3 in which the differential pressure was 0.001 MPa or more, it was 92%, which was a better value.

  The reason why the current efficiency was better in Examples 2 and 3 in which the differential pressure was 0.001 MPa or more than in Examples 1 and 4 in which the differential pressure was 0 was that the pressure at the anode side inlet was When it was higher than the cathode side inlet, Ca could be sufficiently suppressed from flowing from the cathode chamber to the anode chamber via the partition wall, whereas it was thought that Ca slightly flowed into the anode chamber at the same pressure. It is done.

  The molten salt electrolysis method of the present invention is capable of reducing stress applied to the separator and reducing the thickness of the separator by causing the molten salt to flow in the same direction in the anode chamber and the cathode chamber in the electrolytic cell. Current efficiency can be improved. Furthermore, by making the pressure at the anode side inlet higher than the pressure at the cathode side inlet, back reaction due to the inflow of molten salt from the cathode chamber to the anode chamber can be prevented, and the current efficiency can be further improved.

  The electrolytic cell of the present invention can reduce the stress applied to the separator because the molten salt can flow in the same direction in the anode chamber and the cathode chamber. Further, the Ti production method of the present invention is not limited to metal Ti, and can be used for production of alloy Ti by using a molten salt containing an alloy component.

It is a figure which shows the structural example of Ca adjustment tank in which the Ca density | concentration exchange method of this invention is performed. It is a figure which shows the structural example of the diaphragm which consists of ceramics. It is a figure which shows the example of a process at the time of implementing the manufacturing method of Ti of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electrolytic cell 11 Electrolytic cell container 12 Anode 13 Cathode 14 Bottom plate 15 Inlet 15a Anode side injection port 15b Cathode side injection port 16 Lid 17 Discharge port 17a Anode side discharge port 17b Cathode side discharge port 18 Diaphragm 18a Diaphragm part 18b Step 18c Step 18d Spacer 18e Step 21 Anode chamber 22 Cathode chamber 23 Anode-side pump 24 Cathode-side pump 25 Piping 26 Tank 31 Reduction process 32 Separation process 33 Melting process 34 Ingot

Claims (9)

An anode, a cathode facing the anode, and a separator disposed between the anode and the cathode;
An anode chamber having the anode and a cathode chamber having the cathode, separated by the separator;
In an electrolytic cell for electrolyzing the molten salt, having an inlet for molten salt at one end of the anode chamber and the cathode chamber, respectively, and an outlet for the molten salt at the other end of the anode chamber and the cathode chamber, respectively. ,
The molten salt flows from the inlet of the anode chamber and the cathode chamber in the same direction in the anode chamber and the cathode chamber, and the pressure at the inlet of the anode chamber is equal to or higher than the pressure at the inlet of the cathode chamber. A molten salt electrolysis method, wherein the molten salt is injected so that   2. The molten salt electrolysis method according to claim 1, wherein the molten salt is injected so that the pressure at the inlet of the anode chamber is larger than the pressure at the inlet of the cathode chamber.   The molten salt electrolysis method according to claim 1 or 2, wherein the flow direction of the molten salt is vertically upward. The molten salt electrolysis method according to claim 1, wherein the molten salt contains CaCl ₂ .   5. The molten salt electrolysis method according to claim 4, wherein the molten salt is injected so that a Ca concentration in the molten salt in the cathode chamber rising by electrolysis is equal to or lower than a saturated concentration.   The molten salt electrolysis method according to claim 4 or 5, wherein Ca is dissolved in the molten salt injected into the cathode chamber, and Ca is not dissolved in the molten salt injected into the anode chamber. An electrolytic cell having an anode and a cathode facing the anode, and electrolyzing molten salt,
A separator disposed between the anode and the cathode, an anode chamber having the anode, and a cathode chamber having the cathode, separated by the separator,
One end of each of the anode chamber and the cathode chamber has an inlet for molten salt, and the other end of the anode chamber and the cathode chamber has an outlet for the molten salt, and the molten salt is disposed in the anode chamber and the cathode chamber. An electrolyzer characterized by flowing in the same direction.   The said separator is a diaphragm which consists of a metal sintered compact, The electrolytic method of the molten salt in any one of Claims 1-5, or the electrolytic cell of Claim 6. A reduction step of introducing a first molten salt containing CaCl ₂ and dissolving Ca into a reaction vessel, and reducing TiCl ₄ with Ca in the molten salt to generate Ti particles in the first molten salt. When,
Separating the Ti particles from the first molten salt;
In the method for producing Ti, comprising electrolyzing the first molten salt to generate Ca by increasing the Ca concentration in the first molten salt,
In the electrolysis step, the method for electrolyzing a molten salt according to any one of claims 1 to 5 and 8 is applied, the first molten salt is injected into the cathode chamber, and CaCl ₂ is injected into the anode chamber. A method for producing Ti, comprising injecting a second molten salt containing Ca and not dissolved therein.

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