JP2006009054A - Method for producing titanium and titanium alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing titanium and a titanium alloy by electrolyzing a titanium oxide-containing metal oxide in a molten salt, thus reducing the titanium oxide or the like. <P>SOLUTION: Titanium oxide-containing metal oxide powder 3 is charged to a reduction region (for example, a mesh basket 4) and is dipped into a molten salt 5 comprising calcium chloride. With the mesh basket as the cathode, while stirring the titanium oxide-containing metal oxide powder at the inside of the mesh basket, electric current is made to flow between the mesh basket and the anode 6 dipped into the molten salt in the region on the anode side so as to reduce the metal oxide powder. When the stirring is performed by the blowing-in of an inert gas, the titanium oxide powder can be easily and effectively stirred at the inside of the mesh basket. Further, when metal titanium 8 is beforehand mixed into the metal oxide powder, satisfactory electrical conductivity can be secured, and its production can be efficiently performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing titanium and a titanium alloy by directly reducing a metal oxide containing titanium oxide by electrolysis in a molten salt containing calcium chloride.

  Metallic titanium and titanium alloys have excellent properties such as corrosion resistance, light weight and high strength (ie, high specific strength), and equipment materials for chemical plants including aircraft materials, petroleum refining, and petrochemistry. It is widely used in various industrial fields as materials for heat transfer tubes, heat exchanger materials, automobile parts, medical equipment, and sports equipment.

In the production of titanium metal, titanium oxide (TiO ₂ ) obtained by pretreatment of ores such as rutile (TiO ₂ ) and ilmenite (FeTiO ₃ ) is usually chlorinated to form titanium tetrachloride (TiCl ₄ ). A crawl method (Mg reduction method) is used in which a metal is reduced by reacting with magnesium to form sponge metal titanium.

However, in the process a batch method in which the titanium sponge titanium tetrachloride, it is difficult to continuously. In addition, for reuse of magnesium chloride produced by reduction of titanium tetrachloride (MgCl _2), molten salt MgCl ₂ When separating into Mg and Cl ₂ by the electrolytic method, a great amount of energy (electric power) is consumed. Therefore, development of the manufacturing method of the metal titanium which can be operated continuously and can reduce electric power consumption is calculated | required.

  One of the expected methods is to obtain titanium metal by directly reducing titanium oxide.

  As a technique related to this, Patent Document 1 discloses a direct electrolysis method in which oxygen is removed from an oxide of a metal such as Ti, Si, and Ge by electrolysis in a chloride molten salt. In this method, for example, when a metal titanium containing oxygen is used as a cathode and current is supplied in the molten salt, oxygen in the titanium moves (dissolves) in the electrolyte rather than metal ions in the molten salt precipitate on the surface of the titanium. It utilizes the phenomenon that the reaction proceeds preferentially, and it is said that not only oxygen in titanium metal but also oxygen can be removed from titanium oxide by contacting titanium oxide with the cathode. However, it is difficult to immediately put this method into practical use, and various problems need to be solved.

  Patent Document 2 discloses that titanium oxide powder is reduced and deoxidized with calcium ions and electrons generated by electrolysis of a calcium chloride molten salt containing calcium oxide to form titanium metal, and from the bottom of the reducing vessel. A refining method and a refining apparatus for extracting metallic titanium have been proposed. Here, a method for reducing titanium oxide by placing a molybdenum container containing titanium oxide powder inside a calcium chloride bath is described.

  However, in this method, a part of titanium oxide is reduced to metal titanium, but there is a problem that subsequent reduction does not proceed. It is considered that calcium oxide (CaO) produced at the time of reduction makes the periphery highly viscous and makes it difficult for calcium oxide to be diffused and transferred, and calcium oxide precipitates and adheres to the surface of titanium oxide.

  In addition, a part of the titanium oxide powder in the molybdenum container is rolled up with the flow of the molten salt (flow in the bath), diffuses and flows in the molten salt, is reduced to titanium, and precipitates at the bottom of the electrolytic cell. However, a part thereof is carbonized by carbon of the anode to form titanium carbide (TiC), or titanium with an increased carbon concentration. For this reason, titanium extracted from the bottom is mixed with titanium in which such C contamination (that is, C concentration increase, TiC formation) is generated, and C contamination cannot be removed even by vacuum arc melting (VAR). The workability of the resulting titanium material is degraded.

JP-T-2002-517613

JP 2003-129268 A

  The object of the present invention is to immerse the titanium oxide powder in a calcium chloride molten salt and reduce the amount of the titanium oxide powder by electrolysis to form titanium metal, that is, the calcium oxide (CaO) produced during the reduction. Resolves the problem of C contamination of titanium produced by the delay and suppression of the reduction reaction due to precipitation, adhesion, etc. on the titanium oxide surface, and the diffusion and reduction of titanium oxide powder into the molten salt (especially the anode side), An object of the present invention is to provide a method for producing titanium and a titanium alloy, in which a metal oxide containing titanium oxide is reduced by electrolysis.

  In order to solve the above-mentioned problems, the present inventors have studied a method of proceeding the reduction reaction by electrolyzing the titanium oxide powder while being held inside the cathode (inside surrounded by the cathode). If the titanium oxide powder can be retained inside the cathode, diffusion of titanium oxide powder and titanium metal produced by reduction into the molten salt (especially the anode side) and contact with the anode (graphite electrode) can be prevented. C contamination can be suppressed, and in addition, it is possible to prevent other impurities other than titanium carbide, which cannot be avoided by the method of recovering metallic titanium from the bottom of the reducing vessel (electrolyzer), from entering metallic titanium. Because.

  That is, in order to hold the titanium oxide powder inside the cathode, the cathode is made into a mesh shape and the titanium oxide powder is put therein, and the titanium oxide powder and the metal titanium produced by the reduction stay in the mesh cage and are outside the cage. We tried to reduce titanium oxide by electrolysis in a state where only molten salt circulated through the network. As a result, although C contamination (increased C concentration, formation of TiC) of titanium could be suppressed, calcium oxide adhered to the titanium oxide inside the reticulum and the reduction reaction could not be continued.

  Therefore, when argon (Ar) gas was blown from the bottom of the mesh net, the titanium oxide powder was stirred as the molten salt flowed inside the mesh net, and the reduction reaction proceeded to effectively convert the titanium oxide into titanium metal. It was found to be reduced.

This invention was made | formed as a result of such examination, and the summary exists in the manufacturing method of the following titanium and titanium alloy. That is,
“A molten salt containing calcium chloride is placed in an electrolytic cell constituted by a network in which the boundary between the reduction region and the anode side region forms a cathode, and the titanium oxide-containing metal oxide powder is put into the molten salt in the reduction region. Titanium and a titanium alloy that reduce the titanium oxide-containing metal oxide powder by supplying electricity to the anode immersed in the molten salt in the anode side region while stirring and stirring the titanium oxide-containing metal oxide powder in the reduction region Manufacturing method ”.

  Here, the “titanium oxide-containing metal oxide” is an oxide of an element to be added as an alloy component to titanium, such as vanadium oxide, aluminum oxide, chromium oxide, etc. A metal oxide containing

The “molten salt containing calcium chloride” refers to only calcium chloride (CaCl ₂ ), or in addition to calcium chloride, potassium chloride (KCl), calcium fluoride (CaF ₂ ) for adjusting the melting point, viscosity, etc. ) And the like. When a mixed salt is used as the molten salt, if the concentration of calcium compound such as calcium chloride or calcium fluoride is too low, the calcium ion in the molten salt becomes insufficient and the reaction rate decreases, so the concentration of the calcium compound is 10 mass. % Or more is desirable. In the following description, it is also referred to as “electrolyte”.

Further, the “reduction region” is a cathode side region in which a metal oxide, for example, titanium oxide (TiO ₂ ) is reduced to produce a metal titanium. In this case, the net provided at the boundary with the anode side region functions as a cathode. The “anode side region” is a region other than the reduction region in which the anode is immersed and the boundary with the reduction region is divided by a net.

  In the method for producing titanium and titanium alloy of the present invention, if the method of “constituting the reduction region with a mesh” (this is referred to as the method of “Embodiment 1”), the handling of titanium oxide-containing metal oxide powder, In particular, it is easy to recover the residue (titanium titanium) after the reduction, and the mesh screen constituting the cathode can be removed from the electrolytic cell.

  In the production method of the present invention (including the method of “Embodiment 1”), if the method of “using the anode as a graphite electrode” (this is referred to as the method of “Embodiment 2”), the melt containing high-temperature calcium chloride is used. Excellent in thermal shock resistance even in salt, desirable.

  In the method of “Embodiment 1” or “Embodiment 2” of the present invention, “a mesh cage configured to prevent the flow of molten salt between the inside of the mesh cage and the outside of the mesh mesh except for the mesh of the mesh mesh” is used. By adopting the method (this is referred to as the method of “Embodiment 3”), it is possible to prevent the titanium oxide-containing metal oxide powder and the generated titanium from leaking out of the net and suppress the formation of titanium carbide. Can do.

  In the production method of the present invention (including the methods of “Embodiments 1 to 3”), a method of “stirring the titanium oxide-containing metal oxide powder inside the mesh cage by blowing an inert gas” If the method of “Aspect 4” is employed, the titanium oxide powder can be easily and effectively stirred inside the mesh cage.

  In the production method of the present invention (including the method of “Embodiments 1 to 4”), a method of “recovering the residue inside the net after the reduction is completed” (this is referred to as the method of “Embodiment 5”). ) Can be used to recover titanium or titanium alloy obtained by reduction. In particular, in the case of using the method of “Embodiment 1” in which the reduction region is formed of a mesh, it is only necessary to pull up the mesh so that the collection is extremely easy.

  In addition, in the production method of the present invention (including the methods of “Embodiments 1 to 5”), a method of “mixing titanium metal in advance in a titanium oxide-containing metal oxide powder to be put into a mesh bag” Adopting the method of “Aspect 6”) ensures good electrical conductivity and enables efficient production.

  According to the method for producing titanium and titanium alloy of the present invention, titanium or titanium alloy can be easily obtained by directly reducing titanium oxide-containing metal oxide powder by electrolysis.

As described above, the titanium and titanium alloy production method of the present invention includes the following steps (1) and (2).
(1) A molten salt containing calcium chloride is placed in an electrolytic cell composed of a network in which the boundary between the reduction region and the anode side region forms a cathode, and the titanium oxide-containing metal oxide powder is melted in the reduction region. (2) Stirring the titanium oxide-containing metal oxide powder in the reduction region and reducing the titanium oxide-containing metal oxide powder by passing current between the anode and the anode immersed in the molten salt in the anode side region That is, in the step (1), the titanium oxide-containing metal oxide powder is put into the molten salt in the electrolytic cell, and the electrolytic cell is reduced by a net (this net functions as a cathode). It is divided into a region and an anode side region.

Providing such a network boundary suppresses the movement of metallic titanium produced in the reduction region to the anode side region while ensuring the circulation of the molten salt, and also produces C (carbon) and CaC produced in the anode side region. _This is to avoid titanium contamination due to penetration of ₂ (calcium carbide) into the reduction region. By providing a net, it is also possible to promote the reduction reaction by stirring only in the reduction region.

  The net is used as a cathode because the titanium oxide-containing metal oxide powder in the reduction region is reduced to metal titanium.

  The material of the mesh becomes a cathode when energized, and therefore needs to be made of a conductor. Furthermore, it is required to withstand long-term use in a molten salt containing high-temperature calcium chloride and to have workability capable of relatively easily producing fine mesh wrinkles. For example, iron (steel), titanium, molybdenum or the like can be used.

  The shape of the net is not particularly limited. For example, it may be a flat mesh that can bisect the electrolytic cell in an appropriate position perpendicularly to the reduction region and the anode side region, or it may be a unique one that takes into account the efficiency of the reaction in the reduction region, the stirring effect, etc. The shape may be sufficient. As will be described later, it may be formed in a net-like shape in consideration of convenience at the time of recovery of titanium metal produced by reduction.

  The size of the mesh is not limited, but it must be so fine that the titanium oxide-containing metal oxide powder does not leak into the anode region through the mesh in a high-temperature molten salt. In particular, in the method of the present invention, as described in the subsequent step (2), the titanium oxide-containing metal oxide powder inside the meshwork is stirred and fluidized, so that it does not leak even under such conditions. Consideration is required.

  As the titanium oxide-containing metal oxide powder to be introduced into the molten salt in the reduction region, titanium oxide alone may be used. For example, titanium oxide containing vanadium oxide, aluminum oxide, chromium oxide, or the like may be used. Since these oxides are reduced in the same manner as titanium oxide and become solid solution (titanium alloy) in titanium as vanadium, aluminum, chromium, etc., the mixing amount of vanadium oxide, aluminum oxide, chromium oxide, etc. What is necessary is just to set it as the quantity corresponding to the alloy composition.

  The particle size of the titanium oxide-containing metal oxide powder is desirably in the range of 0.03 to 0.2 mm. If the particle size exceeds 0.2 mm, the metal oxide segregates due to coarse particles, making it difficult to obtain a uniform alloy. If the particle size is less than 0.03 mm, it passes through the network during electrolysis, and the concentration of the alloy components is actually It will be lower than the concentration added as an oxide.

  In the step (2), while stirring the titanium oxide-containing metal oxide powder in the reduction region, the titanium oxide-containing metal oxide powder is reduced by energizing the anode immersed in the molten salt in the anode side region. .

When electrified and electrolyzed between the net (cathode) constituting the boundary between the reduction region and the anode side region and the anode immersed in the molten salt in the anode side region, the cathode (net) and titanium oxide-containing metal oxide powder The electrode reaction of the following formula (1) occurs at the contact with (for example, titanium oxide), and further, the chemical reaction of the formula (2) proceeds near the cathode and is oxidized by Ca generated by the reaction of the formula (1). Titanium (TiO ₂ ) is reduced to produce metallic titanium (Ti). If an oxide of an element to be added as an alloy component is contained in titanium such as vanadium oxide, it is similarly reduced to produce metal V or the like to form a titanium alloy.

Cathode: 2Ca ²⁺ + 4e ⁻ → 2Ca (1)
TiO ₂ + 2Ca → Ti + 2CaO (2)
FIG. 1 is a diagram schematically showing a state generated as a result of the reactions (1) and (2) at and near the contact point between the cathode (net) and titanium oxide. Titanium oxide 1 (TiO ₂₎ is, for example, is housed in a metal container, such as molybdenum, when in contact with the network 2 (cathode) in a stationary state, as shown in FIG. 1, the electrolyte of the contacts (CaCl ₂ ) Is given electrons (e ⁻ ) from the network 2, and Ca is generated by the reaction of the formula (1). This Ca immediately reacts with titanium oxide 1 (TiO ₂ ) and the formula (2) to produce metallic titanium (Ti) and calcium oxide (CaO).

However, since titanium oxide 1 (TiO ₂₎ is a stationary state, as described above, diffusion of calcium oxide (CaO), the movement is less likely to occur, CaO is deposited on the surface of the TiO _2, deposited, the surface of TiO ₂ Covered with CaO. As a result, the reaction of formula (2) does not proceed, and the reduction of titanium oxide 1 (TiO ₂ ) does not proceed.

When the titanium oxide 1 (TiO ₂ ) is in contact with the net 2 in a state where the titanium oxide 1 in the reduction region is stirred and the electrolytic solution is flowed as in the production method of the present invention, calcium oxide is used. (CaO) easily migrates into the electrolytic solution (CaCl ₂ ), passes through the net 2, diffuses and moves to the anode side region, and reaches the vicinity of the anode.

When the titanium oxide 1 separated from the mesh 2 by stirring again comes into contact with the mesh 2 (cathode), further metal titanium is generated by the above reaction at the contact (a portion surrounded by a broken line in FIG. 1 and indicated as Ti) Is Ti produced by the first contact with the mesh 2). When Ti is generated in this way, oxygen (O ₂ ) is released from the TiO ₂ surface, so that the titanium oxide 1 is porous, and the electrolyte (CaCl ₂ ) is made of the titanium oxide 1. It penetrates to the inside. Therefore, it is inferred that the reduction of TiO ₂ to Ti by the reaction of the above formulas (1) and (2) easily proceeds to the inside of the titanium oxide 1 while the titanium oxide 1 repeatedly contacts and leaves the net 2. Is done.

Eventually, in order for the reduction of titanium oxide 1 (TiO ₂ ) to proceed, the network 2 for supplying electrons (e ⁻ ), the electrolyte solution (CaCl ₂ ) for receiving it, and the titanium oxide 1 (reduction target) Although the coexistence of the three (TiO ₂ ) is indispensable, in the production method of the present invention, the titanium oxide 1 in the reduction region is stirred and fluidized together with the electrolytic solution, so that the TiO ₂ surface is always the electrolytic solution (CaCl ₂ ). As long as titanium oxide 1 (TiO ₂ ) is in contact with the net 2 during the manufacturing process, this condition is satisfied. In addition, when the titanium oxide 1 in the reduction region is stirred and fluidized, it seems that the reaction between the net 2 and the titanium oxide 1 is less likely to occur, but the reaction hardly occurs, but actually the reduction reaction proceeds. It is considered that the flowing titanium oxide 1 powder is reduced at the moment when it contacts the net 2.

On the other hand, in general, an electrode reaction of the following formula (3) occurs in the anode, but if the anode is a graphite electrode (carbon), an electrode reaction of the following formula (4) occurs, and carbon dioxide (CO ₂ ) is generated from the anode surface. Will occur.

^{_{Anode: 2CaO → O 2 + 2Ca 2+}} + 4e - ·· (3)
Anode (graphite): 2CaO + C → CO ₂ + 2Ca ²⁺ + 4e ⁻ (4)
The material of the anode is not particularly limited as long as it is a conductor, but the graphite electrode is a good electrical conductor and excellent in chemical resistance and thermal shock resistance, and it is desirable to use this (method of “Embodiment 2”). .

  In the step (2), the titanium oxide-containing metal oxide powder is stirred when energizing between the net (cathode) and the anode. Thereby, as partly mentioned in the description of FIG. 1 described above, a remarkable effect is obtained in that the reduction reaction of titanium oxide continues and the C contamination of titanium is prevented. That is, the production method of the present invention is characterized by stirring the titanium oxide in the reduction region. Here, the effects of stirring are organized and outlined.

(A) In the case of no stirring When a net is provided at the boundary between the reduction region and the anode side region, the reaction of the above formulas (1) and (2) occurs in the portion where the titanium oxide is in contact with the net, and Ti is Although generated, the diffusion and movement of CaO generated at the same time hardly occur, and the surface of TiO ₂ is covered with CaO. For this reason, the reaction of the formula (2) does not continue, and the generation of Ti is delayed.

On the other hand, since the reaction of the formula (1) proceeds, unreacted Ca is generated, dissolved in the electrolytic solution (CaCl ₂ ), and diffused and moved to the anode side region. This unreacted Ca reduces the CO ₂ produced by the reaction of the above formula (4) at the anode (graphite electrode) to generate C (see the following formula (5)), and further reacts with this C. CaC ₂ (calcium carbide) is produced (the following formula (6)). The produced CaC ₂ diffuses and moves to the reduction region in a state dissolved in CaCl ₂ and reacts with Ti produced by the reactions of the formulas (1) and (2) to form TiC (titanium carbide) (described below). (7) Formula). That is, C contamination occurs.

CO ₂ + 2Ca → C + 2CaO (5)
2C + Ca → CaC ₂・ ・ （6）
2Ti + CaC ₂ → 2TiC + Ca (7)
Even when the net is not provided, although there is a difference in the diffusion and movement speed of Ca and the like, the same reaction occurs, causing a delay in Ti generation and C contamination.

(B) When there is no mesh and the entire inside of the electrolytic cell is stirred In this case, CaO produced by the reaction of formula (2) diffuses at the cathode (there is no mesh, so a separate metal cathode is used) Since it is easily removed, the production of Ti continues, but the C 2 produced by the reduction of CO ₂ produced by the reaction of the formula (4) (the above formula (5)) is converted into the reaction of the formula (2). It reacts with the produced Ti to form TiC (the following formula (8)). Furthermore, this C reacts with Ca to produce CaC ₂ (the above formula (6)). The generated CaC ₂ reacts with Ti to form TiC as described above (formula (7)).

Ti + C → TiC (8)
Since the entire interior of the electrolytic cell is agitated, forming reaction (equation (8)) of said TiC, the reaction CaC ₂ is generated (the equation (6)), the C constituting the anode (graphite electrodes) Also involved.

  In other words, in this case, C contamination occurs, and the progress of the contamination is remarkable only because no net is provided to prevent the flow of the produced Ti in the electrolytic cell.

(C) When there is a mesh and the entire inside of the electrolytic cell (inside and outside of the mesh) is agitated Ti is produced by the formula (2) in the vicinity of the mesh, but since the mesh is provided, it is outside the reduction region of the produced Ti Diffusion and movement into are prevented. On the other hand, Ca generated in the vicinity of the net according to the formula (1) is consumed in the reaction of the formula (2), but the outside of the net (anode side region) is also stirred, so the flow of CaCl ₂ outside the net As a result, a part of the unreacted Ca also moves to the anode side region.

Therefore, the reduction reaction of the CO ₂ generated by the reaction of the formula (4) (the formula (5)) and the subsequent generation reaction of the CaC ₂ (the formula (6)) proceed, and the generated CaC ₂ is It also moves to the vicinity of the net by stirring and reacts with Ti in the vicinity of the net to form TiC (formula (7)). This TiC dissolves in CaCl ₂ and moves into the reduction region, so that C contamination occurs.

(D) When there is a net and only the inside of the reduction area (inside the net) is stirred (method employed in the present invention)
Ti is generated by the equation (2) in the vicinity of the net, but since the net is provided, diffusion and movement of the generated Ti outside the reduction region are hindered. On the other hand, Ca generated in the vicinity of the net according to the formula (1) does not move to the outside of the net without the liquid flow (anode side region) and is consumed in the reaction of the formula (2). Does not generate.

Therefore, the CO ₂ reduction reaction (formula (5)) and the subsequent CaC ₂ production reaction (formula (6)) do not proceed, and C contamination does not occur.

  In addition, since the inside of a reduction | restoration area | region (net | network) is stirred, the CaO produced | generated by (2) Formula is easy to be spread | diffused and removed, and the production | generation of Ti continues.

  As described above, in the step (2), since the stirring is performed when the current is passed between the mesh and the anode, a remarkable effect is obtained for the progress of the reduction reaction and the prevention of C contamination of titanium.

  The following various methods can be applied to stir the titanium oxide in the reduction region (in the net). That is, there are a method in which an inert gas is blown into the reduction region and stirring, a method in which a stirring bar is inserted from above the reduction region, and a magnetic stirring method using a stirrer disposed at the bottom of the reduction region. In the case where the reduction region is composed of a mesh cage as in the method of “Embodiment 1”, the mesh oxide 4 itself is swung up and down, left and right, or rotated to rotate the metal oxide in the mesh cage. A method of flowing the powder is also applicable.

  Among them, the method of stirring by injecting an inert gas from the gas introduction pipe 7 illustrated in FIG. 2 (the method of “Embodiment 4”) stirs the titanium oxide powder easily and effectively in the reduction region. Therefore, it is preferable.

  After the reduction is completed, the residue in the reduction region is recovered to obtain titanium or a titanium alloy (the method of “Embodiment 5”).

  Further, an example of the method of “Embodiment 1” in which the reduction region is formed of a net is described with reference to the drawings.

  FIG. 2 is a diagram showing an example of a schematic configuration of an apparatus capable of carrying out the manufacturing method of “Embodiment 1” in the embodiment of the present invention. As shown in the figure, a gas introduction for injecting an inert gas into the net 4 by immersing the net 4 and the anode 6 into which the titanium oxide-containing metal oxide powder 3 is put in a molten salt 5 containing calcium chloride. A tube 7 is attached. The net 4 constitutes the cathode.

  The first step in this production method is a step of “immersing the titanium oxide-containing metal oxide powder 3 in a conductive mesh cage 4 and immersing it in a molten salt 5 containing calcium chloride”.

  The material of the mesh cage 4 used here is as described above, and, for example, iron (steel), titanium, molybdenum or the like can be adopted.

  The shape of the net 4 is not particularly limited. Cylindrical, square tube, narrowed down parts of the ridge, and other special shapes can be used, but they can be installed in the electrolytic cell, charged with metal oxide powder 3 and the metal produced What is necessary is just to select the thing of an appropriate shape in consideration of handling property, such as taking out titanium etc.

  Moreover, the distribution of the molten salt between the inside of the net and the outside of the net so that the titanium oxide-containing metal oxide powder 3 and the generated titanium can be prevented from leaking out of the net 4 and the C contamination of titanium can be suppressed. It is desirable to use a mesh having a shape that does not occur except in the mesh of the mesh (that is, adopting the method of “Embodiment 3”). For example, in FIG. 2, a mesh cage in which the upper end of the mesh of the mesh mesh 4 is located above the surface of the molten salt 5 may be used.

  The size of the mesh of the mesh screen 4 is not limited as described above, but it is necessary that the mesh size of the titanium oxide-containing metal oxide powder 3 is so fine that it does not leak out of the mesh mesh 4 in the high-temperature molten salt 5. There is.

  As shown in FIG. 2, the next step is as follows: “Stirring the titanium oxide-containing metal oxide powder 3 in the mesh net and energizing the anode 6 immersed in the molten salt 5 to conduct titanium oxide-containing metal oxidation. It is a process of “reducing product powder 3”.

When electrification is conducted between the mesh screen 4 and the anode 6 which are cathodes, and electrolysis, at the contact point between the cathode (network 4) and the titanium oxide-containing metal oxide powder 3 (for example, titanium oxide), as described above, The reactions of the formulas (1) and (2) proceed, titanium oxide (TiO ₂ ) is reduced, and metal Ti is generated.

  On the other hand, at the anode, as described above, the reaction of the formula (3) or the formula (4) proceeds.

  In this example, stirring of the titanium oxide-containing metal oxide powder 3 inside the mesh cage 4 is performed by a method of stirring by blowing an inert gas from the gas introduction pipe 7 (method of “embodiment 4”). It is preferable because the titanium oxide powder can be easily and effectively flowed inside the net.

  After the reduction is completed, titanium or a titanium alloy can be obtained by recovering the residue in the net (the method of “Embodiment 5”). In this case, since it is only necessary to pull the net cage out of the molten salt, it is much easier than, for example, a method of recovering metallic titanium from the bottom of the reduction vessel (electrolyzer).

  FIG. 3 is a diagram showing a schematic configuration example of an apparatus capable of carrying out the manufacturing method of the present invention in another embodiment of the present invention. This is a case in which a titanium oxide-containing metal oxide powder 8 in which metal titanium is mixed in advance is put in a net cage (method of “Embodiment 6”). That is, the configuration is the same as that of the apparatus shown in FIG. 2, but the raw materials to be put into the net are different.

  As shown in FIG. 2, the titanium oxide-containing metal oxide powder is mixed with the metal titanium. When only the titanium oxide-containing metal oxide powder is put in the mesh and the mesh is stirred, the electricity required for the electrolysis is mixed. The reason for this is to make up for the lack of contact points through which.

  Since the mixed metal titanium is recovered as it is, there is no limit to the amount of mixing, but it is 0.5% by mass or more based on the total amount of metal oxide powder and metal titanium charged in the mesh cage. If they are mixed, it is possible to obtain a significant improvement in conductivity and an increase in production efficiency. On the other hand, even if the content exceeds 20% by mass, the increase in production efficiency due to the improvement in conductivity shows a saturation tendency. Accordingly, the mixing ratio of titanium metal is preferably 0.5 to 20% by mass.

  The particle size of the titanium metal to be mixed is not particularly limited. In general, the smaller the particle size, the more contacts through which electricity flows.However, if the particle size is too small compared to the metal oxide powder, the function as a contact is difficult to exert. It may be determined as appropriate in consideration.

  As described above, according to the method of “Embodiment 6” using the titanium oxide-containing metal oxide powder in which metal titanium is mixed in advance as a raw material to be put into the netting, good conductivity can be secured, and production of titanium or titanium alloy Can be performed efficiently.

According to the method for producing titanium and titanium alloy of the present invention described above, calcium oxide (CaO) produced during reduction is deposited on and adhered to the surface of the titanium oxide powder, thereby preventing the reduction of titanium oxide (TiO ₂ ). Never do.

Since no net is provided, a part of the titanium oxide powder (TiO ₂ ) that is wound up with the flow of the molten salt and diffuses and flows in the molten salt is reduced to Ti by Ca in the molten salt (TiO ₂ + 2Ca). → Ti + 2CaO), and a part of this Ti does not react with C in the molten salt or the graphite electrode (formula (8)) to produce titanium carbide (TiC). In addition, a part of the titanium metal (Ti) produced by the reduction does not react with C while being diffused and flown in the molten salt to produce titanium carbide (TiC).

  The titanium and titanium alloy obtained by the production method of the present invention are usually in the form of granules or small lumps in which they are partially connected, and if dissolved as they are, a small titanium or titanium alloy ingot can be obtained. . Further, the granular material can be compressed by a cold press and melted, and in this case, it can be formed into a desired shape and melted. Further, it can be used as raw material titanium or titanium alloy for powder metallurgy.

  According to the method for producing titanium and titanium alloy of the present invention, titanium or titanium alloy can be easily obtained by directly reducing titanium oxide-containing metal oxide powder by electrolysis. Therefore, the manufacturing method of the present invention is effectively used as a simple means for providing materials used for devices and parts that require the corrosion resistance of titanium or titanium alloys, particularly in various industrial fields. be able to.

It is a figure which shows typically the state which arises as a result of the reaction in the contact of the cathode (net | network) and titanium oxide, and its vicinity. It is a figure which shows the schematic structural example of the apparatus which can implement the manufacturing method of this invention. This is a case where a titanium oxide-containing metal oxide powder is put into a net. It is a figure which shows the schematic structural example of the apparatus which can implement the manufacturing method of this invention, and is a case where the titanium oxide containing metal oxide powder which mixed the titanium metal beforehand in the meshwork is put.

Explanation of symbols

1: Titanium oxide 2: Mesh 3: Metal oxide powder containing titanium oxide 4: Mesh 5: Molten salt 6: Anode 7: Gas introduction tube 8: Metal titanium

Claims (7)

  A molten salt containing calcium chloride is placed in an electrolytic cell composed of a network in which the boundary between the reducing region and the anode side region forms a cathode, and a titanium oxide-containing metal oxide powder is put into the molten salt in the reducing region. The titanium oxide-containing metal oxide powder is reduced by energizing the anode immersed in the molten salt in the anode side region while stirring the titanium oxide-containing metal oxide powder in the reduction region. A method for producing titanium and titanium alloys.   The method for producing titanium and a titanium alloy according to claim 1, wherein the reduction region is composed of a net.   The method for producing titanium and a titanium alloy according to claim 1 or 2, wherein the anode is a graphite electrode.   4. The titanium and titanium alloy according to claim 2, wherein the net is configured such that the molten salt does not flow between the inside of the net and the outside of the net other than the net of the net. 5. Production method.   The method for producing titanium and a titanium alloy according to any one of claims 1 to 4, wherein the stirring of the titanium oxide-containing metal oxide powder in the reduction region is performed by blowing an inert gas.   6. The method for producing titanium and a titanium alloy according to claim 1, wherein the residue in the reduction region is recovered after the reduction is completed. The method for producing titanium and titanium alloy according to any one of claims 1 to 6, wherein metal titanium is mixed in advance with titanium oxide-containing metal oxide powder to be introduced into the reduction region.

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