WO2022230403A1

WO2022230403A1 - Metal titanium production method and metal titanium electrodeposit

Info

Publication number: WO2022230403A1
Application number: PCT/JP2022/011426
Authority: WO
Inventors: 大輔鈴木; 雄太中條; 和宏熊本; 松秀堀川; 秀樹藤井
Original assignee: 東邦チタニウム株式会社
Priority date: 2021-04-30
Filing date: 2022-03-14
Publication date: 2022-11-03
Also published as: JPWO2022230403A1; CA3217057A1; EP4332273A1; US20240191381A1

Abstract

Provided is a metal titanium production method for producing metal titanium through molten salt electrolysis by using a conductive material containing titanium, aluminum, and oxygen. In this metal titanium production method, a refinement process comprises: a crude electrodeposition step for obtaining a titanium-containing electrodeposit TC by performing, in a chloride bath Bf, molten salt electrolysis using an electrode that contains a TiAlO conductive material; and at least one round of a refined electrodeposition step for performing, in a chloride bath Bf, molten salt electrolysis using an electrode that contains a titanium-containing electrodeposit TC. Regarding the chloride bath Bf used in the crude electrodeposition step and the chloride bath Bf used in the refined electrodeposition step, at least one of the chloride baths Bf contains 30 mol% or more of magnesium chloride.

Description

Method for producing metallic titanium and metallic titanium electrodeposit

The present invention relates to a method for producing metallic titanium and a metallic titanium electrodeposit.

　In general, the production of titanium metal is carried out by the Kroll method. However, the production involves many steps.

By the way, conventionally, a technique for manufacturing titanium alloys mainly by molten salt electrolysis has been known. For example, Patent Literature 1 discloses a method of producing a titanium alloy by heat-treating a raw material containing titanium ore and aluminum and then subjecting the obtained raw material to molten salt electrolysis.

Japanese Patent Publication No. 2015-507696

In the manufacturing method described in Patent Document 1 above, a chloride bath composed of sodium chloride and potassium chloride is used to refine the titanium alloy. In this refining, a refined titanium product with a predetermined aluminum content and oxygen content is obtained (see Table 3 of Patent Document 1). Such refined titanium products have at least a high aluminum content, which makes them unsuitable for the production of other titanium alloy products and titanium metal products, although they can be used as raw materials for aluminum-containing titanium alloy products.

Therefore, in one embodiment, an object of the present invention is to provide a method for producing metallic titanium by molten salt electrolysis using a conductive material containing titanium, aluminum, oxygen and other impurities.

The inventors of the present invention conducted various studies to reduce the impurity content (especially the oxygen content) by molten salt electrolysis to obtain a titanium alloy as disclosed in Patent Document 1, for example. It has been found that not only the oxygen content but also the aluminum content can be reduced depending on the composition of the chloride bath used in the molten salt electrolysis.

For example, molten salt electrolysis is sometimes carried out for the purpose of refining metals and alloys. As a result of intensive studies on how to reduce the oxygen content while maintaining the composition of the titanium master alloy, it was found that when molten salt electrolysis was performed using a chloride bath containing a predetermined amount of magnesium chloride, oxygen and aluminum other than It has been found that not only the impurity content but also the aluminum content can be reduced. On the other hand, when molten salt electrolysis is performed in a chloride bath containing sodium chloride and potassium chloride, as in the production method described in Patent Document 1, the aluminum content cannot be sufficiently reduced.

This makes it possible, for example, to produce metallic titanium from titanium ore without implementing the Kroll method. It also becomes possible to use this metallic titanium to produce titanium alloy products that do not contain aluminum.

That is, in one aspect of the present invention, there is provided a method for producing titanium metal, including a refining step of refining a TiAlO conductive material containing titanium, aluminum, and oxygen, wherein the refining step includes the TiAlO conductive material in a chloride bath. A crude electrodeposition step of obtaining a titanium-containing electrodeposit by performing molten salt electrolysis using an electrode containing a material, and after the crude electrodeposition step, melting using the electrode containing the titanium-containing electrodeposit in a chloride bath and one or more refinement electrodeposition steps of salt electrolysis, wherein at least one of the chloride bath used in the crude electrodeposition step and the chloride bath used in the refinement electrodeposition step is 30 mol. % or more of magnesium chloride, a method for producing metallic titanium.

In one embodiment of the method for producing metallic titanium according to the present invention, at least one of the chloride bath used in the crude electrodeposition step and the chloride bath used in the refined electrodeposition step contains 50 mol % of the chloride bath. Contains more than magnesium chloride.

In one embodiment of the method for producing metallic titanium according to the present invention, the chloride bath used in the crude electrodeposition step and at least one chloride bath used in the refined electrodeposition step are magnesium chloride containing 30 mol % or more of magnesium chloride. respectively.

In one embodiment of the method for producing metallic titanium according to the present invention, the chloride bath used in the crude electrodeposition step and at least one chloride bath used in the refined electrodeposition step are magnesium chloride containing 50 mol % or more of magnesium chloride. respectively.

In one embodiment of the method for producing metallic titanium according to the present invention, the TiAlO conductive material is obtained by heat-treating a chemical blend containing a titanium ore containing titanium oxide, aluminum, and a separating agent before the refining step. Further includes an extraction step.

In one embodiment of the method for producing metallic titanium according to the present invention, the molar ratio of titanium oxide, aluminum and separating agent contained in the chemical blend is 3:4-7:2-6.

In one embodiment of the method for producing metallic titanium according to the present invention, the separating agent contains one or more selected from calcium fluoride, calcium oxide and sodium fluoride.

In one embodiment of the method for producing metallic titanium according to the present invention, the metallic titanium has an aluminum content of 100 mass ppm or less and an oxygen content of 500 mass ppm or less.

In one embodiment of the method for producing metallic titanium according to the present invention, the metallic titanium has a nitrogen content of 0.03% by mass or less, a carbon content of 0.01% by mass or less, and an iron content of is 0.010% by mass or less, the magnesium content is 0.05% by mass or less, the nickel content is 0.01% by mass or less, the chromium content is 0.005% by mass or less, and silicon The content is 0.001% by mass or less, the manganese content is 0.05% by mass or less, and the tin content is 0.01% by mass or less.

In another aspect, a metal titanium electrodeposit having an aluminum content of 5 mass ppm or more and 100 mass ppm or less and an oxygen content of 100 mass ppm or more and 500 mass ppm or less It is a titanium electrodeposit.

In one embodiment of the metal titanium electrodeposit according to the present invention, the nitrogen content is 0.001% by mass or more and 0.03% by mass or less, and the carbon content is 0.0004% by mass or more and 0.01% by mass. % or less, the iron content is 0.010 mass % or less, the magnesium content is 0.05 mass % or less, the nickel content is 0.01 mass % or less, and the chromium content is 0.01 mass % or less. 005% by mass or less, a silicon content of 0.001% by mass or less, a manganese content of 0.05% by mass or less, and a tin content of 0.01% by mass or less.

According to one embodiment of the present invention, it is possible to provide a method for producing metallic titanium by molten salt electrolysis using a conductive material containing titanium, aluminum, and oxygen.

(A) to (D) are diagrams for explaining refining steps in an embodiment of the method for producing metallic titanium according to the present invention. (A) to (D) are diagrams for explaining refining steps in another embodiment of the method for producing metallic titanium according to the present invention. (A) to (D) are diagrams for explaining refining steps in another embodiment of the method for producing metallic titanium according to the present invention. (A) to (D) are diagrams for explaining refining steps in another embodiment of the method for producing metallic titanium according to the present invention. (A) to (D) are diagrams for explaining refining steps in another embodiment of the method for producing metallic titanium according to the present invention. (A) to (D) are diagrams for explaining the refining process in Example 1. FIG. 6(A) taken along the line XX. FIG. (A) is a photograph of the titanium-containing electrodeposit after the crude electrodeposition step obtained in Example 1, and (B) is a photograph of the titanium-containing electrodeposit after the crude electrodeposition step obtained in Example 1. It is the photograph obtained by SEM observation of a thing. (A) is a photograph of the titanium metal electrodeposit after the purification electrodeposition step obtained in Example 1, and (B) is a photograph of the metal titanium electrodeposit after the purification electrodeposition step obtained in Example 1. It is the photograph obtained by SEM observation of a thing.

The present invention is not limited to the embodiments described below, and can be embodied by modifying the constituent elements without departing from the spirit of the present invention. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in each embodiment. For example, the invention may be formed by omitting some components from all the components shown in the embodiments. In addition, in the drawings, some members are shown schematically in order to facilitate understanding of the embodiments included in the invention, and the illustrated sizes, positional relationships, etc. may not necessarily be accurate.
In this specification, the "metallic titanium electrodeposit" is generally granular in appearance, and when microscopically observed, it often has a three-dimensional shape in which dendritic or polyhedral fine grains are linked (Fig. 9). (B)).

[1. Method for producing metallic titanium]
One embodiment of the method for producing titanium metal according to the present invention includes a refining step to reduce the impurity content. Note that an extraction step may be further included before the refining step.
An example of each step will be described below.

<Extraction process>
The extraction step heat-treats a chemical blend containing, for example, a titanium ore containing titanium oxide, aluminum, and a separating agent to obtain a TiAlO conductive material. It is considered that the following reactions are utilized by the heat treatment. That is, in the extraction step, a thermite reaction is used to reduce titanium oxide, which is a metal oxide, with aluminum. A chemical blend is a raw material mixture for obtaining a TiAlO conductive material. Titanium oxide in titanium ore is not suitable for molten salt electrolysis due to its low electrical conductivity. Therefore, the TiAlO conductive material can be produced by performing the extraction step using titanium ore. Since the TiAlO conductive material has a relatively high electrical conductivity, it can be used in the later-described refining process for producing metallic titanium. In the extraction step, the TiAlO conductive material may be produced by appropriately referring to the known method described in Patent Document 1 (Japanese Patent Publication No. 2015-507696) or the like.

(titanium ore)
The content of titanium oxide in the titanium ore is not limited, but is, for example, 50% by mass or more, for example 80% by mass or more, for example 90% by mass or more. Titanium ore includes not only those obtained by mining, but also those that have been so-called upgraded. When the titanium oxide content in the titanium ore is low, appropriate treatment such as leaching may be performed to improve the titanium oxide content (that is, upgrade treatment).

(Separating agent)
Separating agents are incorporated into the chemical blend for the purpose of separating TiAlO conductors and slag by-products in the extraction process. Those having such a function can be used as a separating agent, but the separating agent preferably contains one or more selected from calcium fluoride, calcium oxide and sodium fluoride. From the viewpoint of morphology, it is more preferable to contain calcium fluoride. Therefore, the separating agent may be calcium fluoride alone.

(Chemical blend composition)
In order to prepare the above chemical blend, the amounts of titanium ore, aluminum and separating agent are adjusted so that the molar ratio of titanium oxide:aluminum:separating agent=3:4-7:2-6, for example. Thus, the molar ratio of titanium oxide to aluminum to separating agent in the chemical blend is 3:4-7:2-6.

(Heat treatment conditions)
Regarding the heat treatment conditions, the temperature inside the container is, for example, 1500° C. or higher and 1800° C. or lower in an inert gas (eg, Ar) atmosphere. From the viewpoint of heat resistance and the like, examples of materials for the inner wall of the container include carbon, ceramics, and the like.

(TiAlO conductive material)
The TiAlO conductive material obtained in the extraction step has, for example, a titanium content of 50% by mass or more and 80% by mass or less, an aluminum content of 3% by mass or more and 40% by mass or less, and an oxygen content of 0.5% by mass or more. It is 2% by mass or more and 40% by mass or less.
In addition, the said titanium content is 60 mass % or more as a lower limit.
Moreover, the said aluminum content is 5 mass % or more as a lower limit. On the other hand, the upper limit of the aluminum content is, for example, 30% by mass or less, for example, 20% by mass or less.
The lower limit of the oxygen content is, for example, 3% by mass or more, 5% by mass or more, or 8% by mass or more. On the other hand, the upper limit of the oxygen content is, for example, 30% by mass or less, for example, 20% by mass or less.
In the present invention, even with a TiAlO conductive material having a high aluminum content and a high oxygen content, it is possible to obtain metallic titanium with a low impurity content and high purity.
As for the method for measuring the impurity content of each component of the TiAlO conductive material, the measuring method described in the examples of this specification can be adopted.

(Resistivity)
The upper limit of the specific resistance of the TiAlO conductive material may be, for example, 1×10 ⁻⁴ Ω·m or less from the viewpoint of efficiently performing molten salt electrolysis in the refining process described later for producing metallic titanium. Moreover, since the TiAlO conductive material should be moderately conductive, the lower limit of the specific resistance may be, for example, 1×10 ⁻⁸ Ω·m or more. The lower limit of the specific resistance may be, for example, 1×10 ⁻⁷ Ω·m or more, for example, 5×10 ⁻⁷ Ω·m or more.
As for the method for measuring the resistivity of the TiAlO conductive material, the measuring method described in the examples of this specification can be adopted.

<Smelting process>
The refining process uses an electrolytic device to refine the TiAlO conductive material in order to reduce the impurity content. That is, in the refining process, metallic titanium with high purity is obtained by reducing the contents of mainly aluminum and oxygen in the TiAlO conductive material, as well as other ore-derived elements. The refining process includes a crude electrodeposition step and one or more refinement electrodeposition steps in which molten salt electrolysis is performed using an electrode containing the titanium-containing electrodeposit obtained in the crude electrodeposition step.

(Electrolyzer)
In one embodiment, various electrolytic devices can be used. An example of the electrolysis apparatus 100 shown in FIG. 1A is of a batch type, and includes an electrolytic bath 110 in the form of a sealed container that stores a chloride bath Bf, and an anode 120 and a cathode 130 that are immersed in the chloride bath Bf. and a power source (not shown) connected to the anode 120 and the cathode 130 via conductive wires to energize the anode 120 and the cathode 130 . Although illustration is omitted, the electrolytic device 100 usually has a structure that can be opened and closed in order to install or take out the anode and cathode. Although not shown, the electrolysis apparatus 100 has an opening for gas supply and exhaust in order to make the space above the chloride bath Bf an inert gas atmosphere. Although not shown, the electrolysis apparatus 100 is provided with a heater at an appropriate location so that the chloride bath Bf can be maintained in a molten state by heating. The material of the electrolytic bath 110 is not particularly limited as long as it has heat resistance and corrosion resistance. Also, the electrodes may further include a bipolar electrode.

(Molten salt)
The molten salt that constitutes the chloride bath may contain, for example, 70 mol % or more, such as 80 mol % or more, such as 90 mol % or more of alkali metal chlorides and alkaline earth metal chlorides. In the present invention, reasons for not using a fluoride bath, a bromide bath and an iodide bath in place of the chloride bath include high corrosiveness, high environmental load and high cost.
At least one chloride bath Bf of the chloride bath used in the crude electrodeposition step and the chloride bath used in the refinement electrodeposition step reduces not only the oxygen content but also the aluminum content to produce metallic titanium From the viewpoint of manufacturing, it contains 30 mol% or more of magnesium chloride. Using a chloride bath with a high magnesium chloride content can increase the effect of reducing the aluminum content. It should be noted that, for example, only the chloride bath used in the crude electrodeposition step may contain the predetermined amount of magnesium chloride, or at least Only one chloride bath may contain the predetermined amount of magnesium chloride. In addition, at least one of the chloride bath used in the crude electrodeposition step and the chloride bath used in the refinement electrodeposition step which is performed one or more times contains the predetermined amount of magnesium chloride. may
In addition, from the viewpoint of more reliably reducing the aluminum content and oxygen content of the electrodeposition, the chloride bath used in the crude electrodeposition step and the chloride bath used in the refinement step performed one or more times At least one chloride bath of the baths may each contain the amount of magnesium chloride described above.
The above chloride bath containing a predetermined amount of magnesium chloride is effective in reducing the aluminum content and oxygen content in the electrodeposit, and the lower limit of the magnesium chloride content is preferably 30 mol % or more. , more preferably 50 mol % or more, still more preferably 80 mol % or more, still more preferably 85 mol % or more, still more preferably 90 mol % or more. The chloride bath contains lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), rubidium chloride (RbCl), cesium chloride (CsCl), beryllium chloride (BeCl ₂ ), calcium chloride (CaCl ₂ ) one or more metal chlorides selected from strontium chloride (SrCl ₂ ) and barium chloride (BaCl ₂ ), for example 70 mol% or less, for example 50 mol% or less, for example 20 mol% or less, or for example 15 mol% or less , and may further contain, for example, 10 mol % or less. Further, the chloride bath may optionally contain lower titanium chloride, such as titanium dichloride and titanium trichloride. The content of the lower titanium chloride may be appropriately adjusted.
Regarding the above chlorides, the specific salt type and content can be appropriately determined in consideration of the operating temperature and the like. The content on a molar basis is measured by ICP emission spectrometry and atomic absorption spectrometry.
Here, the content on a molar basis is calculated as follows. After solidifying a molten salt sample collected from the chloride bath, the components of the sample are subjected to ICP emission spectrometry and atomic absorption spectrometry to calculate the content of each metal ion on a molar basis in the chloride bath Bf. do. If the chloride bath contained MgCl ₂ , NaCl, KCl, CaCl ₂ , LiCl, TiCl ₂ and TiCl ₃ , the metal ion content was determined by atomic absorption spectroscopy for Na and K and ICP emission spectroscopy for the others. (Mm) is obtained by adding the content of magnesium ions, the content of sodium ions, the content of potassium ions, the content of calcium ions, the content of lithium ions, and the content of titanium ions. The molar content of each component contained in the chloride bath is calculated by dividing the metal ion content of each component by the total metal ion content (Mm) and expressing it as a percentage. can be done. As described above, the content of chloride is determined based on the content of metal ions contained in the chloride bath.

(anode/cathode)
Each of the anode 120 and the cathode 130 can be, for example, rod-shaped, a long band that is used while being moved, a cylinder, a plate-shaped, a cylinder or other columnar shape, or a block-shaped shape. For example, a TiAlO conductive material as the anode 120 can be melted and cast to form the anode. If the inter-electrode distance between the anode 120 and the cathode 130 is to be set within a specific range, it is preferable that the shapes of the opposing portions of the anode 120 and the cathode 130 are similar in vertical cross section. For example, if a cylindrical, rod-shaped, or columnar cathode 130 is used and the anode 120 is placed outside it, the anode 120 may also be cylindrical. In this case, since the cylindrical anode 120 surrounds the cathode 130, the area where the electrodeposits are produced can be increased. Alternatively, a rod-shaped or column-shaped cathode 130 that is rotatable with a fixed axial position may be used, and a plate-shaped anode 120 having an arc-shaped cross section may be used at the opposed portion. Even in this case, the opposing portions of the anode 120 and the cathode 130 can maintain substantially the same inter-electrode distance.
Alternatively, the anode 120 may be formed by placing the TiAlO conductive material obtained in the above-described extraction process in the form of granules or powder in a metal basket (for example, made of nickel) having a lower ionization tendency than titanium. . In this case, the basket BK has many through holes, and the shape of the basket BK can be treated as the shape of the anode 120 . Further, even if the cage is electrically connected, the cage BK is less likely to elute into the chloride bath Bf, and mainly the TiAlO conductive material is eluted. In the description using the drawings, for ease of understanding, the portion where the TiAlO conductive material or the like is eluted is sometimes described with the symbol of anode.
As for the shape of the cathode 130, at least part of the surface of the cathode 130 on which metallic titanium is deposited may be curved. When such a cathode 130 is used, metal titanium can be electrodeposited on the surface of the cathode 130 while rotating the cathode 130, which contributes to miniaturization of the apparatus during continuous production.

Next, examples of the crude electrodeposition step and the refined electrodeposition step will be described with reference to FIGS. 1(A) to (D) to 5(A) to (D).
When the chloride bath used in the crude electrodeposition step has a bath composition containing the aforementioned predetermined amount of magnesium chloride, the chloride bath used in the refined electrodeposition step contains the above-mentioned predetermined amount of magnesium chloride. composition, or another bath composition that does not contain the predetermined amount of magnesium chloride. Further, when the chloride bath used in the refinement electrodeposition step has a bath composition containing a predetermined amount of magnesium chloride as described above, the chloride bath used in the crude electrodeposition step contains the above-mentioned predetermined amount of magnesium chloride. composition, or another bath composition that does not contain the predetermined amount of magnesium chloride.
1A to 1D to 5A to 5D can be connected to a power supply (not shown), and a control mechanism for the power supply (not shown). is capable of appropriately switching conductive lines for supplying current according to each anode and each cathode.

<Crude electrodeposition step>
In the crude electrodeposition step, molten salt electrolysis is performed in a chloride bath Bf using an electrode containing a TiAlO conductive material to obtain a titanium-containing electrodeposit.
For example, in the crude electrodeposition step, as shown in FIG. 1A, a nickel cage BK in which a TiAlO conductive material as an anode 120 is placed and a titanium cathode 130 are placed in a chloride bath Bf. . The control mechanism then supplies current to the anode 120 and the cathode 130 via the conductive line EL connected to the cage BK and the cathode 130, thereby performing molten salt electrolysis.
In the drawing, the anodes 120 are placed in separate baskets BK, but the anodes may be placed in, for example, ring-shaped nickel baskets (see FIGS. 6A and 7). Alternatively, a rod-shaped or plate-shaped anode obtained by casting a TiAlO conductive material may be directly connected to the conductive wire without using a cage.

(chloride bath temperature, current density)
The temperature of the chloride bath Bf may be appropriately changed depending on the components in the chloride bath Bf. That is, the temperature of the chloride bath Bf may be appropriately determined from the viewpoints of maintaining the molten state of the chloride bath and eliminating energy loss due to excessive heating. At this time, it is also possible to appropriately determine the temperature of the chloride bath Bf with reference to the melting point of each metal chloride. To give a specific example, the temperature of the chloride bath Bf is controlled within a range of, for example, 450° C. or higher and 900° C. or lower.
Also, the current density of the cathode 130 is not particularly limited and may be determined as appropriate. The current density of the cathode 130 may be, for example, 0.01 A/cm ² or more and 5 A/cm ² or less. The current density of the cathode 130 can be calculated by the formula: current density (A/cm ² )=current (A)÷electrolysis area (cm ² ). Here, the electrolysis area, for example, in the case of a cathode having a cylindrical surface, is calculated by the formula: electrolysis area (cm ² )=cathode immersion surface area=cathode diameter (cm)×π×cathode height (cm).
In addition to continuously flowing the current through the electrode, a pulse current may be used in which an energization stop period is provided in which the current value is set to zero (that is, no energization), and the energization period and the energization stop period are alternately repeated. good.

The inside of the electrolytic cell 110 is controlled to an inert atmosphere such as argon, for example, from the viewpoint of suppressing an increase in the content of impurities in the titanium-containing electrodeposit due to the contamination of moisture and the like in the air.

Next, as shown in FIG. 1B, as the anode 120 containing titanium, which has a higher ionization tendency than nickel, is eluted into the chloride bath Bf, the anode 120 is consumed, and the impurity content on the surface of the cathode 130 A titanium-containing electrodeposit TC having a reduced is formed. Then, the control mechanism stops the current supply to end the molten salt electrolysis.

The titanium-containing electrodeposit TC formed on the surface of the cathode 130 taken out from the electrolytic cell 110 is recovered by peeling it off with a cutting tool or the like. The titanium-containing electrodeposit TC may be washed and dried as described below. Washing and drying may be performed together with the cathode 130 or may be performed after recovery from the cathode 130 .
As an example, the cathode 130 is removed from the electrolytic cell 110, and the cathode 130 and the titanium-containing electrodeposit TC are washed with an acid and/or water to dissolve and remove the molten salt adhering thereto. Next, the titanium-containing electrodeposit TC is peeled off from the surface of the cathode 130 with a cutting tool or the like. Then, the titanium-containing electrodeposit TC is placed in a container and vacuum-dried to evaporate moisture.

<Purification electrodeposition step>
In the refinement electrodeposition step, after the crude electrodeposition step, molten salt electrolysis is performed in a chloride bath Bf using an electrode containing titanium-containing electrodeposits TC. Thus, by further purifying the titanium-containing electrodeposit TC obtained in the crude electrodeposition step, a metal titanium electrodeposit TP having a further reduced impurity content can be obtained. The refining electrodeposition step can be performed one or more times, and from the second time onwards, the metallic titanium electrodeposit obtained last time is used as an electrode.
For example, as shown in FIG. 1C, a nickel cage BK in which a titanium-containing electrodeposit TC as an anode 122 is placed and a titanium cathode 130 are placed in a chloride bath Bf. Molten salt electrolysis is then performed by the control mechanism supplying current to the anode 122 and the cathode 130 via the conductive line EL connected to the cage BK and the cathode 130 . The cathode 130 may be the same as the cathode 130 used in the crude electrodeposition step, or may be replaced with a new cathode.

The composition of the chloride bath Bf, the temperature of the chloride bath, and the current density in the refinement electrodeposition step are the same as in the crude electrodeposition step, so the explanation is omitted.

Next, as shown in FIG. 1(D), the titanium-containing anode 122 is exhausted as it is eluted into the chloride bath Bf, and a metallic titanium electrode having a reduced impurity content is deposited on the surface of the cathode 130 . A precipitate TP is formed. Then, the control mechanism stops the current supply to end the molten salt electrolysis.

The metal titanium electrodeposit TP formed on the surface of the cathode 130 taken out from the electrolytic cell 110 is recovered by peeling it off with a cutting tool or the like. The titanium metal electrodeposit TP may be subjected to the washing and drying described above in the crude electrodeposition step. Washing and drying may be performed together with the cathode 130 or may be performed after recovery from the cathode 130 .
This yields titanium metal with reduced aluminum and oxygen content.

In the embodiment shown in FIGS. 1(C) to 1(D), the purification electrodeposition step is performed once, but in order to further reduce the impurity content and further improve the purity of metallic titanium, the purification electrodeposition step is performed. A step may be performed multiple times. More specifically, the obtained metal titanium electrodeposit TP is placed in a nickel cage BK in the electrolytic bath 110, and the control mechanism controls the flow between the metal titanium electrodeposit TP as an anode and the titanium cathode 130. Molten salt electrolysis is performed by supplying a current to . Every time such an operation is repeated, it becomes possible to recover titanium metal in which the aluminum content and the oxygen content are more reliably reduced. However, from the viewpoint of manufacturing cost, the number of repetitions may be appropriately selected. The purification electrodeposition step is, for example, one or more and five or less times, and for example, one or more and three or less times.

(Composition of metallic titanium)
According to the refining process described above, it is possible to obtain metallic titanium having an aluminum content of 100 mass ppm or less, an oxygen content of 500 mass ppm or less, and a balance of titanium and unavoidable impurities. These unavoidable impurities are often ore-derived impurities and chloride bath-derived components. The composition of metallic titanium here corresponds to the titanium purity of so-called industrial pure titanium, and metallic titanium has a low impurity content, for example, the total impurity content is 3000 mass ppm or less.
In addition, the said aluminum content is 50 mass ppm or less as an upper limit. On the other hand, the lower limit of the aluminum content is, for example, 10 mass ppm or more, for example 20 mass ppm or more.
Moreover, the upper limit of the oxygen content is, for example, 450 mass ppm or less, for example, 400 mass ppm or less. On the other hand, the lower limit of the oxygen content is, for example, 100 mass ppm or more, for example 200 mass ppm or more.
Further, in a further embodiment, when the above-mentioned unavoidable impurities and the like are more specifically specified, the nitrogen content is 0.03% by mass or less, the carbon content is 0.01% by mass or less, and the iron content is 0.010% by mass or less, magnesium content of 0.05% by mass or less, nickel content of 0.01% by mass or less, chromium content of 0.005% by mass or less, silicon content of 0.001% by mass or less It is also possible to obtain metallic titanium in which the manganese content is further controlled to 0.05% by mass or less and the tin content is controlled to 0.01% by mass or less.
The lower limit of the nitrogen content is, for example, 0.002% by mass or more, for example 0.003% by mass or more. On the other hand, the upper limit of the nitrogen content is, for example, 0.009% by mass or less, for example, 0.008% by mass or less.
In addition, the lower limit of the carbon content is, for example, 0.0006% by mass or more, for example, 0.0008% by mass or more. On the other hand, the upper limit of the carbon content is, for example, 0.008% by mass or less, for example, 0.004% by mass or less.
The upper limit of the iron content is, for example, 0.005% by mass or less, for example 0.003% by mass or less. On the other hand, the lower limit of the magnesium content is, for example, 0.001% by mass or more, for example 0.005% by mass or more.
The upper limit of the nickel content is, for example, 0.008% by mass or less, for example, 0.004% by mass or less.
Further, the chromium content is, as a lower limit, 0.0005% by mass or more, for example 0.001% by mass or more.
The upper limit of the silicon content is, for example, 0.0005% by mass or less.
Further, the manganese content is, as a lower limit, for example 0.001% by mass or more, for example 0.005% by mass or more. On the other hand, the upper limit of the manganese content is, for example, 0.03% by mass or less.
The upper limit of the tin content is, for example, 0.005% by mass or less, for example 0.003% by mass or less.
It is presumed that various pure titanium products and titanium alloy products can be obtained at low cost by using metallic titanium produced according to one embodiment of the present invention.

(another embodiment)
Another embodiment is described below. In the embodiments described below, the points that are different from the above-described embodiments will be mainly described. That is, the configurations described in the above embodiments can be appropriately applied to the following embodiments.
In the embodiment shown in FIGS. 1(A) to 1(D), the anode and the cathode are arranged at approximately the same height, but the crude electrodeposition step and the refinement electrodeposition step can be performed even if the arrangement of the anode and the cathode is changed. It is possible. As an example, an embodiment in which the cathode is arranged on the upper side and the anode is arranged on the lower side will be described below. As shown in FIG. 2(A), in an electrolytic device 200, for example, a nickel base BS is placed on the bottom of an electrolytic bath 210, and a TiAlO conductive material as an anode 220 is placed on the base BS. A titanium cathode 230 is placed at a higher position. Next, the control mechanism supplies current to the anode 220 and the cathode 230 through the conductive line EL connected to the base BS and the cathode 230, thereby performing molten salt electrolysis (rough electrodeposition step).
Next, as shown in FIG. 2(B), as the anode 220 is eluted into the chloride bath Bf, the anode 220 is consumed, and a titanium-containing electrodeposit TC having a reduced impurity content is deposited on the surface of the cathode 230. is formed. Then, the control mechanism stops the current supply to end the molten salt electrolysis.
Next, the titanium-containing electrodeposit TC formed on the surface of the cathode 230 taken out from the electrolytic bath 210 is recovered by peeling it off with a cutting tool or the like. Note that the titanium-containing electrodeposit TC may be washed and dried as described above.
Next, as shown in FIG. 2(C), a nickel-made base BS and a titanium-containing electrodeposit TC as an anode 222 are placed on the base BS at the bottom of the electrolytic cell 210. A titanium cathode 230 is placed at a higher position. Next, the control mechanism supplies current to the anode 222 and the cathode 230 through the conductive line EL connected to the base BS and the cathode 230, thereby performing molten salt electrolysis (refining electrodeposition step).
Next, as shown in FIG. 2(D), as the anode 222 containing titanium is eluted into the chloride bath Bf, the anode 222 is exhausted, and metal titanium electrodeposition with reduced impurity content is deposited on the surface of the cathode 230. Entity TP is formed. Then, the control mechanism stops the current supply to end the molten salt electrolysis.
Next, the cathode 230 is taken out from the electrolytic cell 210, and the metal titanium electrodeposit TP formed on the surface of the cathode 230 is washed, peeled off and dried to obtain metal titanium.

The embodiment shown in FIG. 3 is an embodiment in which at least part of the electrolytic cell is made of nickel and the part made of nickel is used as the cathode. In addition, it is an embodiment in which metallic titanium can be produced without taking out the titanium-containing electrodeposit TC from the chloride bath Bf. As shown in FIG. 3(A), a nickel basket BK in which a TiAlO conductive material as an anode 320 is placed is arranged in the electrolytic device 300 . At this time, by making the material of at least the inner wall of the electrolytic cell 310 nickel, the inner wall serves as the cathode 330 during the molten salt electrolysis. Next, the control mechanism supplies current to the anode 320 and the cathode 330 via the conductive wire EL connected to the cage BK and the cathode 330, thereby performing molten salt electrolysis (rough electrodeposition step).
Next, as shown in FIG. 3B, as the anode 320 is eluted into the chloride bath Bf, the anode 320 is exhausted, and a titanium-containing electrodeposit with reduced impurity content is formed on the inner wall of the electrolytic bath 310. TC is formed. Then, the control mechanism stops the current supply to end the molten salt electrolysis.
Next, the nickel basket BK is removed from the chloride bath Bf.
Next, as shown in FIG. 3C, a titanium cathode 335 is placed in the chloride bath Bf. At this time, the titanium-containing electrodeposit TC formed on the inner wall surface of the nickel electrolytic bath 310 is used as the anode 322 . Next, the control mechanism supplies a current to the anode 322 and the cathode 335 via the conductive wire EL connected to the inner wall of the electrolytic cell 310 and the cathode 335 to perform molten salt electrolysis (refining electrodeposition step). .
Next, as shown in FIG. 3(D), the anode 322 is consumed as the anode 322 is eluted into the chloride bath Bf, and a metallic titanium electrodeposit TP having a reduced impurity content is formed on the surface of the cathode 335. is formed. Then, the control mechanism stops the current supply to end the molten salt electrolysis.
Next, the cathode 335 is taken out from the electrolytic bath 310, and the metal titanium electrodeposit TP formed on the surface of the cathode 335 is washed, peeled off and dried to obtain metal titanium.

Yet another embodiment is described in which metallic titanium can be produced without removing the titanium-containing electrodeposit TC from the chloride bath Bf. As shown in FIG. 4A, a nickel basket BK in which a TiAlO conductive material as an anode 420 is placed is placed in an electrolysis device 400 . Next, two

titanium cathodes

430 and 435 are arranged side by side toward the center from the position where the cage BK is arranged. In this embodiment, from the viewpoint of efficiency of electrodeposition, the titanium cathode 430 preferably has a large number of holes having openings on the anode 420 side and the titanium cathode 435 side. The shape of this hole is not particularly limited, and it may be a through hole with a linear cross section, or a hole with a complicated shape such as that of a porous body. Next, molten salt electrolysis is carried out by supplying electric current to the anode 420 and the cathode 430 through the conductive wire EL to the basket BK and the cathode 430 to which the control mechanism is connected (crude electrodeposition step).
Next, as shown in FIG. 4B, as the anode 420 is eluted into the chloride bath Bf, the anode 420 is exhausted, and a titanium-containing electrodeposit TC having a reduced impurity content is deposited on the surface of the cathode 430. is formed. Then, the control mechanism stops the current supply to end the molten salt electrolysis.
Next, as shown in FIG. 4(C), the cathode 430 (see FIG. 4(B)) having the titanium-containing electrodeposit TC formed on the surface is switched to the anode 424, and the anode whose control mechanism has been switched. Molten salt electrolysis is performed by supplying current to 424 and cathode 435 near the center (refining electrodeposition step). At this time, the titanium-containing electrodeposit TC becomes the anode 422 .
Next, as shown in FIG. 4(D), the anode 422 and possibly also the anode 424 are depleted as they are eluted into the chloride bath Bf, leaving metal with reduced impurity content on the surface of the cathode 435. A titanium electrodeposit TP is formed. Then, the control mechanism stops the current supply to end the molten salt electrolysis.
Next, the cathode 435 is taken out from the electrolytic bath 410, and the metal titanium electrodeposit TP formed on the surface of the cathode 435 is washed, peeled off and dried to obtain metal titanium.

An embodiment will be described in which the titanium-containing electrodeposits TC are continuously electrodeposited a plurality of times without taking them out of the chloride bath Bf and without changing the power supply connection. As shown in FIG. 5(A), an electrolytic device 500 is provided with a nickel cage BK in which a TiAlO conductive material as an anode 520 is placed, a titanium cathode 530, and a titanium bipolar electrode 540 in the center. do. Although the titanium bipolar electrode 540 is illustrated as being thick in FIG. 5A, the titanium bipolar electrode 540 may be thin. Molten salt electrolysis is performed by a control mechanism supplying current to the anode 520 and the cathode 530 via the conductive line EL connected to the cage BK and the cathode 530 .
Next, as shown in FIG. 5B, as the anode 520 is eluted into the chloride bath Bf, the anode 520 is consumed, and the titanium-containing electrodeposit TC with reduced impurity content is deposited on the surface of the bipolar electrode 540. Formed on top. Formation of the titanium-containing electrodeposit TC on this bipolar electrode 540 corresponds to the rough electrodeposition step.
In addition, since a current is flowing between the anode and the cathode, the dissolution of the anode and the dissolution of the bipolar electrode can proceed simultaneously. FIG. 5C shows that the cathode 530 side of the bipolar electrode 540 is eluted. In this embodiment, the bipolar electrode 540 will first elute titanium from the bipolar electrode 540 and then the titanium-containing electrodeposit TC.
Next, as shown in FIG. 5(D), the bipolar electrode 540 and the titanium-containing electrodeposit TC are consumed, and a metal titanium electrodeposit TP with a reduced impurity content is formed on the surface of the cathode 530. (refining electrodeposition step). Next, the current supply is stopped in order to terminate the molten salt electrolysis.
Next, the cathode 530 is taken out from the electrolytic bath 510, and the metal titanium electrodeposit TP formed on the surface of the cathode 530 is washed, peeled off and dried to obtain metal titanium.
In FIG. 5A, a titanium bipolar electrode is arranged, but instead of the bipolar electrode, for example, a titanium-containing electrodeposit TC obtained by subjecting a TiAlO conductive material to molten salt electrolysis is arranged. This may be a double pole.
Alternatively, for example, after the titanium-containing electrodeposit TC is formed on the surface of the double electrode 540 on the anode 520 side, a hook (not shown) attached to the upper end of the double electrode 540 is hooked with a hanging rod or the like to should be rotated 180 degrees. By doing so, the titanium-containing electrodeposit TC faces the cathode 530 .
In the above description, the bipolar electrode and the cathode are described as being made of titanium, but the material can be appropriately changed as long as the electrodeposit can be deposited. Note that the bipolar electrode must have conductivity. Therefore, non-conductive materials such as ceramics cannot be used for the bipolar electrodes.
The bipolar poles may be non-movable or movable as described above. Since electrodeposition and elution can occur simultaneously in the case of a non-movable bipolar electrode, it is preferable to have a large number of holes opening to the anode side and the cathode side. On the other hand, in the case of a movable bipolar electrode, electrodeposition and elution can proceed separately, so such holes as described above are unnecessary. Rather, by eliminating the pores, it is possible to avoid a situation in which the electrodeposits enter the pores and require a long time for elution.
As described above, a plurality of crude electrodeposition steps and refinement electrodeposition steps have been described. These can be carried out in combination as appropriate. For example, after carrying out the crude electrodeposition step of the embodiment shown in FIGS. It is also possible to carry out a purification electrodeposition step of

[2. Titanium Electrodeposit]
The metallic titanium electrodeposit according to the present invention can be produced by the method for producing metallic titanium described above, and has a reduced impurity content. The metal titanium electrodeposit has a low impurity content, for example, the total impurity content is 3000 ppm by mass or less. In one embodiment, the metal titanium electrodeposit has an aluminum content of 5 mass ppm or more and 100 mass ppm or less and an oxygen content of 100 mass ppm or more and 500 mass ppm or less, and the balance is titanium and unavoidable It has a composition consisting of impurities. These unavoidable impurities are often ore-derived impurities and chloride bath-derived components. The content of each of the above components can also be within the range described above in "Composition of metallic titanium".

Moreover, in one embodiment, the above-described unavoidable impurities and the like may be specified more specifically. That is, the nitrogen content in the metal titanium electrodeposit is 0.001% by mass or more and 0.03% by mass or less, and the carbon content is 0.0004% by mass or more and 0.01% by mass or less, The iron content is 0.010% by mass or less, the magnesium content is 0.05% by mass or less, the nickel content is 0.01% by mass or less, and the chromium content is 0.005% by mass or less. The silicon content may be 0.001% by mass or less, the manganese content may be 0.05% by mass or less, and the tin content may be 0.01% by mass or less. The content of each of the above components can also be within the range described above in "Composition of metallic titanium".
The method for measuring the impurity content of each component of the metal titanium electrodeposit is the same as the method for measuring the impurity content of each component of the TiAlO conductive material described above.

(Sieving)
In a further embodiment, the particle size distribution of the metal titanium electrodeposit is not particularly limited, but the proportion of the metal titanium electrodeposits that are above the sieve when sieved through a 300 μm mesh sieve is, on a mass basis, a lower limit of, for example, 60% or more. Yes, and for example 70% or more. In addition, the upper limit of the ratio of the metal titanium electrodeposits to be on the sieve is, for example, 90% or less, for example, 85% or less.
An example of the method for measuring the particle size distribution by sieving is shown below.
In a glove box in an argon atmosphere with an oxygen concentration of 5% by volume or less, the metal titanium electrodeposit is pulverized to such an extent that it does not crush or pulverize, and is sieved using a sieve with an opening of 300 μm. As shown in the following formula (1), the mass (A ₁ ) of the metal titanium electrodeposit on the sieve with an opening of 300 μm is divided by the total mass (A _total ) put into the sieve, and the ratio (α) is expressed as a percentage. Calculated by
α (%) = A1 (g)/ _A ( _total ) x 100

The present invention will be specifically described based on examples and comparative examples. The descriptions of the following examples and comparative examples are merely experimental specific examples for facilitating the understanding of the technical content of the present invention, and the technical scope of the present invention is limited by these specific examples. is not.

[Evaluation of TiAlO conductive material]
First, the TiAlO conductive material used in Examples and Comparative Examples to be described later is a chemical blend containing titanium ore containing titanium oxide, aluminum, and calcium fluoride as a separating agent. After heat treatment under the conditions shown below. , was prepared by post-treatment according to a known method (extraction step). In the extraction process, the amount of titanium ore, aluminum and separating agent charged was adjusted so that the molar ratio of titanium oxide:aluminum:separating agent was within the range of 3:4-7:2-6. A measurement sample collected from the TiAlO conductive material was subjected to ICP emission spectrometry (PS3520UVDDII, manufactured by HITACHI) for metal components, inert gas fusion-infrared absorption method (TC-436AR, manufactured by LECO) for oxygen, and The impurity content of each component was measured by an inert gas fusion-thermal conductivity method (TC-436AR, manufactured by LECO) and a combustion-infrared absorption method for carbon (EMIA-920V2, manufactured by Horiba, Ltd.). This method of measuring the content of the component is also applied to titanium-containing electrodeposits, metal titanium, and metal titanium electrodeposits. Further, the specific resistance of a separate measurement sample collected in the form of a 10 mm square block was measured by a two-terminal measurement method (low resistance meter 3566-RY, manufactured by Tsuruga Electric Co., Ltd.). These results are shown in Table 1.
<Conditions for manufacturing TiAlO conductive material>
Titanium ore: Titanium oxide content 95% by mass
Inert gas: Argon gas Heating temperature: 1500°C to 1800°C

[Manufacturing of metallic titanium]
<Example 1>
(Crude electrodeposition)
An electrolytic device 600 having the configuration shown in FIGS. 6A and 7 was used. The dimensions and shape of the bath portion of the electrolytic cell 610 of the electrolyzer 600 were 300 mmφ×570 mm deep. Next, 30 kg of magnesium chloride (see Table 3) was put into the electrolytic bath 610 of the electrolyzer 600 and dissolved to obtain a chloride bath Bf. Next, an annular nickel cage BK in which an anode 620 made of 5000 g of TiAlO conductive material was placed was placed. A titanium round bar with a diameter of 50 mm×300 mm was prepared as the cathode 630 . The anode 620 and the cathode 630 were arranged such that the height direction of the anode 620 and the cathode 630 was substantially parallel to the depth direction of the chloride bath.

A control mechanism supplied electric current to the anode 620 and the cathode 630 through a conductive line EL connected to the anode 620 and the cathode 630 to perform molten salt electrolysis in the chloride bath Bf. Seven hours after the start of the current supply, the control mechanism stopped the current supply. Incidentally, as shown in FIG. 6(B), a titanium-containing electrodeposit TC deposited over the entire surface of the cathode 630 was obtained.
<Electrolysis conditions>
Inside the electrolytic cell: Ar gas atmosphere Chloride bath temperature: 850°C
Current density: 0.5 A/cm ²

After the current supply was stopped, the cathode 630 was pulled up from the electrolytic bath 610, and the cathode 630 and the titanium-containing electrodeposit TC were washed with water to remove adhering molten salt. A titanium-containing electrodeposit TC containing metallic titanium was peeled off from the cathode 630 with a cutting tool and recovered. Moisture was evaporated from the titanium-containing electrodeposit TC by vacuum separation.

A sample for measurement taken from the titanium-containing electrodeposit TC obtained by crude electrodeposition was measured for the impurity content of each component by the method described above. The results are shown in Table 4.
In addition, the percentage of the titanium-containing electrodeposits TC that were on the sieve was measured by a sieving method (using a sieve with an opening of 300 μm).
Further, a photograph was taken with a camera to confirm the shape of the titanium-containing electrodeposit TC. In order to confirm the shape of the titanium-containing electrodeposit TC, SEM observation was performed under the following measurement conditions. These results are shown in FIGS. 8(A) and 8(B).
<SEM measurement conditions>
SEM: Model JSM-7800F, manufactured by JEOL Accelerating voltage: 10 kV
Magnification: within the range of 60 to 1000 times

(refining electrodeposition)
As shown in FIG. 6(C), 30 kg of magnesium chloride (see Table 3) was put into the electrolytic bath 610 of the electrolyzer 600 and dissolved to form a chloride bath Bf. Next, a ring-shaped nickel basket BK in which an anode 622 made of 500 g of titanium-containing electrodeposit TC was placed was placed. A titanium round bar with a diameter of 50 mm×300 mm was prepared as the cathode 630 . The anode 622 and the cathode 630 were arranged such that the height direction of the anode 622 and the cathode 630 was substantially parallel to the depth direction of the chloride bath.

A control mechanism supplied electric current to the anode 622 and the cathode 630 via a conductive line EL connected to the anode 622 and the cathode 630 to perform molten salt electrolysis in the chloride bath Bf. Two hours after the start of the current supply, the control mechanism stopped the current supply. In addition, as shown in FIG. 6(D), a metal titanium electrodeposit TP deposited over the entire surface of the cathode 130 was obtained.
<Electrolysis conditions>
Inside the electrolytic cell: Ar gas atmosphere Chloride bath temperature: 850°C
Current density: 0.5 A/cm ²

After the supply of current was stopped, the cathode 130 was pulled up from the electrolytic cell 110, and the cathode 130 and the metal titanium electrodeposit TP were pickled and then washed with water to remove the adhering molten salt. The metal titanium electrodeposit TP was peeled off from the cathode 130 with a cutting tool and collected. Moisture was evaporated from the metal titanium electrodeposit TP by vacuum separation.

A sample for measurement taken from the metal titanium electrodeposit TP obtained by the refinement electrodeposition was measured for the impurity content of each component by the method described above. The results are shown in Table 4.
In addition, the proportion of the metal titanium electrodeposits TP that were above the sieve was measured by a sieving method (using a sieve with an opening of 300 μm). These results are shown in Table 5.
Further, a photograph was taken with a camera to confirm the shape of the titanium metal electrodeposit TP. In order to confirm the shape of the metal titanium electrodeposit TP, SEM observation was performed under the following measurement conditions. These results are shown in FIGS. 9(A) and 9(B).
<SEM measurement conditions>
SEM: Model JSM-7800F, manufactured by JEOL Accelerating voltage: 10 kV
Magnification: within the range of 60 to 1000 times

<Examples 2 to 6, Comparative Examples 1 to 3>
Examples 2 to 6 and Comparative Examples 1 to 3 were carried out in the same manner as in Example 1, except that the chloride bath shown in Table 3 was used. Note that only Example 6 was subjected to the refinement electrodeposition step twice. After the electrodeposits prepared in each step were washed with water and vacuum-dried in the same manner as in Example 1, the content of impurities and the percentage of sieved deposits were measured. The results are shown in Tables 4 and 5, respectively.

(Consideration by Example)
In Examples 1 to 6, the metal titanium electrodeposit TP finally obtained by molten salt electrolysis using a TiAlO conductive material having an aluminum content of 11.6 mass% and an oxygen content of 10.3 mass% The aluminum content was below 100 ppm by weight and the oxygen content could be reduced to below 500 ppm by weight. That is, it was confirmed that at least one of the chloride bath used for crude electrodeposition and the chloride bath used for refined electrodeposition contained 30 mol % or more of magnesium chloride. . Therefore, it is presumed that high-purity titanium metal can be produced by using such a titanium metal electrodeposit.
In particular, in Example 1, the chloride bath used in crude electrodeposition and the chloride bath used in refined electrodeposition contained 100 mol% magnesium chloride, so that It is speculated that the aluminum content and oxygen content could be reduced more reliably.
In addition, it is presumed that the aluminum content and the oxygen content in the metal titanium electrodeposit TP could be more reliably reduced by performing the refinement electrodeposition multiple times in Example 6.
On the other hand, in Comparative Examples 1 to 3, neither the chloride bath used for crude electrodeposition nor the chloride bath used for refined electrodeposition contained 30 mol % or more of magnesium chloride. Therefore, in Comparative Examples 1 to 3, it is presumed that the aluminum content could not be reduced satisfactorily.

100, 200, 300, 400, 500, 600

electrolyzer

110, 210, 310, 410, 510, 610

electrolytic cell

120, 122, 220, 222, 320, 322, 420, 422, 424, 520, 620, 622

anode

130, 230, 330, 335, 430, 435, 530, 630 Cathode 540 Bipolar Bf Chloride bath BK Basket BS Base EL Conductive wire TC Titanium-containing electrodeposit TP Metal titanium electrodeposit

It should be noted that the present invention also includes the following inventions.
[1]
A method for producing metallic titanium, comprising a refining step of refining a TiAlO conductive material containing titanium, aluminum, and oxygen,
The refining step includes a crude electrodeposition step of obtaining a titanium-containing electrodeposit by performing molten salt electrolysis using an electrode containing the TiAlO conductive material in a chloride bath;
After the rough electrodeposition step, one or more refinement electrodeposition steps of performing molten salt electrolysis using an electrode containing the titanium-containing electrodeposit in a chloride bath,
A method for producing metallic titanium, wherein at least one of the chloride bath used in the crude electrodeposition step and the chloride bath used in the refined electrodeposition step contains 30 mol % or more of magnesium chloride.
[2]
The metal according to [1], wherein at least one of the chloride bath used in the crude electrodeposition step and the chloride bath used in the refinement electrodeposition step contains 50 mol% or more of magnesium chloride. A method of manufacturing titanium.
[3]
Production of metallic titanium according to [1], wherein the chloride bath used in the crude electrodeposition step and at least one chloride bath used in the refinement electrodeposition step each contain 30 mol % or more of magnesium chloride. Method.
[4]
Production of metallic titanium according to [1], wherein the chloride bath used in the crude electrodeposition step and at least one chloride bath used in the refinement electrodeposition step each contain 50 mol% or more of magnesium chloride. Method.
[5]
Any of [1] to [4], further comprising an extraction step of obtaining the TiAlO conductive material by heat-treating a chemical blend containing titanium ore containing titanium oxide, aluminum, and a separating agent before the refining step. A method for producing metallic titanium according to any one of the above.
[6]
The method for producing metallic titanium according to [5], wherein the molar ratio of titanium oxide, aluminum and separating agent contained in the chemical blend is 3:4 to 7:2 to 6.
[7]
The method for producing metallic titanium according to [5] or [6], wherein the separating agent contains one or more selected from calcium fluoride, calcium oxide and sodium fluoride.
[8]
The method for producing metallic titanium according to any one of [1] to [7], wherein the metallic titanium has an aluminum content of 100 mass ppm or less and an oxygen content of 500 mass ppm or less.
[9]
The nitrogen content in the metal titanium is 0.03% by mass or less, the carbon content is 0.01% by mass or less, the iron content is 0.010% by mass or less, and the magnesium content is 0. 0.05% by mass or less, a nickel content of 0.01% by mass or less, a chromium content of 0.005% by mass or less, a silicon content of 0.001% by mass or less, and a manganese content is 0.05% by mass or less, and the tin content is 0.01% by mass or less.
[10]
A metal titanium electrodeposit,
A metal titanium electrodeposit having an aluminum content of 5 mass ppm or more and 100 mass ppm or less and an oxygen content of 100 mass ppm or more and 500 mass ppm or less.
[11]
Nitrogen content is 0.001% by mass or more and 0.03% by mass or less, carbon content is 0.0004% by mass or more and 0.01% by mass or less, and iron content is 0.010% by mass or less wherein the magnesium content is 0.05% by mass or less, the nickel content is 0.01% by mass or less, the chromium content is 0.005% by mass or less, and the silicon content is 0.001% by mass % or less, a manganese content of 0.05% by mass or less, and a tin content of 0.01% by mass or less, the metal titanium electrodeposit according to [10].

Claims

A method for producing metallic titanium, comprising a refining step of refining a TiAlO conductive material containing titanium, aluminum, and oxygen,
The refining step includes a crude electrodeposition step of obtaining a titanium-containing electrodeposit by performing molten salt electrolysis using an electrode containing the TiAlO conductive material in a chloride bath;
After the rough electrodeposition step, one or more refinement electrodeposition steps of performing molten salt electrolysis using an electrode containing the titanium-containing electrodeposit in a chloride bath,
A method for producing metallic titanium, wherein at least one of the chloride bath used in the crude electrodeposition step and the chloride bath used in the refined electrodeposition step contains 30 mol % or more of magnesium chloride.
2. The metal according to claim 1, wherein at least one of the chloride bath used in the crude electrodeposition step and the chloride bath used in the refinement electrodeposition step contains 50 mol % or more of magnesium chloride. A method of manufacturing titanium.
The production of metallic titanium according to claim 1, wherein the chloride bath used in the crude electrodeposition step and at least one chloride bath used in the refinement electrodeposition step each contain 30 mol% or more of magnesium chloride. Method.
2. The production of metallic titanium according to claim 1, wherein the chloride bath used in the crude electrodeposition step and at least one chloride bath used in the refinement electrodeposition step each contain 50 mol % or more of magnesium chloride. Method.
5. The method according to any one of claims 1 to 4, further comprising an extraction step of heat-treating a chemical blend containing a titanium ore containing titanium oxide, aluminum, and a separating agent to obtain the TiAlO conductive material before the refining step. 10. A method for producing metallic titanium according to claim 1.
The method for producing metallic titanium according to claim 5, wherein the molar ratio of titanium oxide, aluminum and separating agent contained in the chemical blend is 3:4-7:2-6.
The method for producing metallic titanium according to claim 5 or 6, wherein the separating agent contains one or more selected from calcium fluoride, calcium oxide and sodium fluoride.
The method for producing metallic titanium according to any one of claims 1 to 7, wherein the metallic titanium has an aluminum content of 100 mass ppm or less and an oxygen content of 500 mass ppm or less.
The nitrogen content in the metal titanium is 0.03% by mass or less, the carbon content is 0.01% by mass or less, the iron content is 0.010% by mass or less, and the magnesium content is 0. 0.05% by mass or less, a nickel content of 0.01% by mass or less, a chromium content of 0.005% by mass or less, a silicon content of 0.001% by mass or less, and a manganese content is 0.05% by mass or less, and the tin content is 0.01% by mass or less.
A metal titanium electrodeposit,
A metal titanium electrodeposit having an aluminum content of 5 mass ppm or more and 100 mass ppm or less and an oxygen content of 100 mass ppm or more and 500 mass ppm or less.
Nitrogen content is 0.001% by mass or more and 0.03% by mass or less, carbon content is 0.0004% by mass or more and 0.01% by mass or less, and iron content is 0.010% by mass or less wherein the magnesium content is 0.05% by mass or less, the nickel content is 0.01% by mass or less, the chromium content is 0.005% by mass or less, and the silicon content is 0.001% by mass % or less, the manganese content is 0.05 mass % or less, and the tin content is 0.01 mass % or less.