Deposit removal apparatus and deposit removal method for inside face of reduction container and sponge titanium production method

Abstract

To provide a deposit removal apparatus and a deposit removal method which can remove deposits from an inside face of a reduction container used for the reduction reaction of titanium tetrachloride, and a sponge titanium production method.SOLUTION: A deposit removal apparatus 1 is used for the reduction reaction of titanium tetrachloride, and comprises: a cylindrical body part 103; and a bottom part 104 for sealing one side of the body part 103 in the axial direction. The deposit removal apparatus 1 comprises: a container connection part 11 fitted to an opening part 105 on the other side of the body part 103 in the axial direction; an expansion shaft part 21 rotatably held around a central axis of the body part 103 at one end side to the container connection part 11 and expandable in the axial direction at the other end side; arm parts 31; and blade parts 41 provided at tips of the arm parts 31 and having blade edge parts 42 pressed on an inside face 102 of a reduction container 101 and rubbed against the inside face 102 along with the expansion operation and / or rotation operation of the expansion shaft part 21.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for removing deposits from the inner surface of a reduction vessel used in the reduction reaction of titanium tetrachloride, and to a method for producing titanium sponge. [Background technology]

[0002] In the Kroll process, which is widely used industrially as a method for producing metallic titanium, molten metallic magnesium is stored in a reduction vessel to form a molten bath, and titanium tetrachloride is dripped in from above. At this time, the metallic magnesium acts as a reducing agent, causing a reduction reaction in which titanium tetrachloride is reduced to metallic titanium, and the metallic titanium grows as titanium sponge lumps in the reduction vessel.

[0003] When the reduction reaction is completed, the molten bath is discharged from the reduction vessel and the residue is separated by heating under a reduced pressure atmosphere, and then the sponge titanium mass is removed from the reduction vessel. Summary of the Invention [Problem to be solved by the invention]

[0004] The reduction vessel used in the reduction reaction of titanium tetrachloride as described above may have substances attached to its inner surface derived from the titanium tetrachloride, metallic magnesium, etc. used in the reduction reaction. Manual removal of such deposits requires a great deal of effort and time, leading to increased costs including labor costs.

[0005] The object of the present invention is to provide an apparatus and method for removing deposits from the inner surface of a reduction vessel used in the reduction reaction of titanium tetrachloride, which can relatively easily remove deposits from the inner surface of the reduction vessel, and a method for producing titanium sponge. [Means for solving the problem]

[0006] The deposit removal device of the present invention is a device used in a reduction reaction of titanium tetrachloride and removes deposits on the inner surface of a reduction container having a cylindrical body and a bottom sealing one axial side of the body, and is equipped with a container connection part attached to an opening on the other axial side of the body, an extendable shaft part whose one end is rotatably held by the container connection part around the central axis of the body and whose other end is extendable and contractible in the axial direction, an arm part provided on the other end of the extendable shaft part and protruding in the radial direction of the body from the extendable shaft part toward the inner surface of the reduction container, and a blade part provided at the tip of the arm part and having a cutting edge part that is pressed against the inner surface of the reduction container and rubbed against the inner surface as the extendable shaft part extends and contracts and / or rotates.

[0007] In the deposit removal device, it is preferable that the arm portion be a plurality of arms provided at intervals around the telescopic shaft portion.

[0008] It is preferable that the above-mentioned deposit removal device further comprises an arm drive unit, the arm portion having a bendable joint portion and driving the arm portion to bend the joint portion and extend and retract the arm portion inward and outward in the radial direction.

[0009] In this case, it is preferable that the arm driving unit includes an air cylinder capable of driving the arm unit so as to press the cutting edge portion against the inner surface of the reduction container with a constant pressure.

[0010] In the above-described deposit removal device, it is preferable that the cutting edge portion has a curved shape that follows the curved inner surface of the reduction container.

[0011] In the deposit removal device, it is preferable that the length of the blade tip portion is 50 mm to 150 mm.

[0012] In the above-mentioned deposit removal device, it is preferable that the cutting edge portion is pressed against the inner surface of the reduction container at an angle within a range of 30° to 45° with respect to the inner surface.

[0013] The deposit removal method of the present invention is a method for removing deposits from the inner surface of a reduction vessel used in a reduction reaction of titanium tetrachloride and having a cylindrical body and a bottom sealing an opening on one axial side of the body, and comprises using any one of the deposit removal devices described above.

[0014] The above-mentioned method for removing adhesions preferably includes: pressing the cutting edge portion of the blade portion against the inner surface of the reduction container, and extending and / or contracting the telescopic shaft portion in the axial direction, thereby rubbing the cutting edge portion against the inner surface and removing adhesions from the inner surface in the axial direction; and rotating the telescopic shaft portion to change the circumferential position at which the cutting edge portion is pressed against the inner surface of the reduction container.

[0015] The method for producing titanium sponge of the present invention is a method for producing titanium sponge by reducing titanium tetrachloride in a reduction vessel, and after the reduction of titanium tetrachloride, the above-mentioned method for removing deposits is applied to the inner surface of the reduction vessel from which the contents have been removed and from which deposits still remain. Effect of the Invention

[0016] According to the present invention, deposits can be relatively easily removed from the inner surface of a reduction vessel used in the reduction reaction of titanium tetrachloride. [Brief description of the drawings]

[0017] [Figure 1] 1 is a front view showing an embodiment of the deposit removal device of the present invention, with an extendable shaft portion extended in the axial direction and arms extended radially outward. FIG. [Diagram 2] 2 is a front view showing the deposit removal device of FIG. 1 in a state in which the arm portions are retracted radially inward. [Diagram 3] 3 is a front view showing a state in which the telescopic shaft portion is contracted in the axial direction in the deposit removal device of FIG. 2. [Figure 4]4 is a front view showing the deposit removal device in the state shown in FIG. 3 installed in a reduction container. [Diagram 5] 5 is a diagram showing a state in which an extendable shaft portion of the deposit removal device in FIG. 4 is extended in the axial direction, with a reduction container partially cut in the axial direction. FIG. [Figure 6] 6 is a similar view of the deposit removal device of FIG. 5, showing the arm portions of the device extended radially outward. FIG. [Figure 7] FIG. 7 is a partially enlarged view of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the drawings are merely schematic illustrations of an embodiment for ease of understanding, and the dimensions, shapes, numbers of members, and other aspects of each part in the drawings may be changed as appropriate.

[0019] (Apparatus and method for removing deposits) As shown in Figs. 5 and 6, an attachment removal device 1 according to one embodiment of the present invention is intended to remove attachments from an inner surface 102 of a reduction vessel 101 used in a reduction reaction of titanium tetrachloride.

[0020] After the reduction reaction of titanium tetrachloride in the reduction vessel 101 is completed, substances containing Ti and the like originating from the titanium tetrachloride and metallic magnesium used in the reduction reaction remain attached to the inner surface 102 of the reduction vessel 101. If an operator were to manually clean and remove such deposits from the inner surface 102, it would require a lot of time and effort. However, by using the deposit removal device 1 of this embodiment, the deposits can be easily removed simply by the operator installing and operating the deposit removal device 1.

[0021] As shown in Figures 4 to 6, the reduction container 101 has a cylindrical body 103 whose cross section perpendicular to the axial direction or depth direction (the vertical direction in Figures 4 to 6) is a perfect circle, an ellipse, an oval, or another circular shape, and a bottom 104 that seals one side in the axial direction of the body 103 (the lower side in Figures 4 to 6). Note that in Figures 5 and 6, in order to make it easier to understand how deposits on the inner surface 102 of the reduction container 101 are removed by the deposit removal device 1, a part of the body 103 and the bottom 104 of the reduction container 101 are shown in a cross section cut along the central axis.

[0022] The other axial side (the upper side in Figs. 4 to 6) of the body 103 of the reduction container 101 is an opening 105 that opens the hollow interior of the body 103 to the outside. A flange portion 106 having a brim shape such as an annular shape may be provided around the opening 105.

[0023] The deposit removal device 1 has a configuration suitable for removing deposits on the inner surface 102 of the reduction container 101 as described above. More specifically, as shown in Fig. 5 and Fig. 6, the deposit removal device 1 includes a container connection part 11 attached to the opening 105 of the body part 103 of the reduction container 101, a rotatable and extendable telescopic shaft part 21 held by the container connection part 11 at one end side (the end side located on the upper side in Fig. 5 and Fig. 6), an arm part 31 provided on the other end side (the end side located on the lower side in Fig. 5 and Fig. 6) of the telescopic shaft part 21, and a blade part 41 provided at the tip of the arm part 31 and having a cutting edge part 42.

[0024] The container connection part 11 is not particularly limited as long as it can be connected to the opening 105 of the body part 103 of the reduction container 101 and can hold the telescopic shaft part 21 rotatably around the central axis of the body part 103. The container connection part 11 in the illustrated example has a frame shape in which adjacent ones of a plurality of, for example, four, support columns 12 arranged at intervals around the central axis of the body part 103 are connected to each other by two or more plate-like members 13, and the telescopic shaft part 21 is provided at the center. As shown in Figures 4 to 6, the support columns 12 are installed and attached on the end faces or flange parts 106 around the opening 105 of the reduction container 101, and function to support the deposit removal device 1 with respect to the reduction container 101 like a so-called outrigger. The support columns 12 may be structured to be telescopic in the longitudinal direction.

[0025] One end of the telescopic shaft portion 21 is held rotatably around the central axis relative to the container connection portion 11. As a result, when a rotational driving force is applied to the telescopic shaft portion 21 from the driving source 23 on the one end side, a rotational movement occurs around the central axis of the telescopic shaft portion 21, and the arm portion 31 provided on the other end side of the telescopic shaft portion 21 is displaced in the circumferential direction accordingly.

[0026] 5 and 6, the telescopic shaft section 21 can be configured by fitting together a plurality of cylindrical members 22a-22c having different inner and outer diameters. In this case, when a telescopic driving force is applied to the telescopic shaft section 21 from the driving source 23, the plurality of cylindrical members 22a-22c are inserted and removed from each other, and the other end side of the telescopic shaft section 21 can be extended and retracted in the axial direction. FIGS. 1 and 2 show the telescopic shaft section 21 in an extended state, and FIG. 3 shows the telescopic shaft section 21 in a retracted state. In the deposit removal device 1 having the frame-shaped container connection section 11 as shown in the figures, when the telescopic shaft section 21 is retracted, the arm section 31 and the blade section 41 may be stored inside the inner side of the support column 12 of the container connection section 11 as shown in FIG. 3.

[0027] As shown in FIG. 5 and FIG. 6, the arm portion 31 is provided on the other end side of the telescopic shaft portion 21 so as to protrude from the telescopic shaft portion 21 toward the inner surface 102 of the reduction container 101 in the radial direction of the body portion 103. From the viewpoint of efficiently removing deposits on the inner surface 102, preferably, a plurality of arm portions 31, for example, four arm portions 31, can be provided at intervals around the telescopic shaft portion 21 as shown in the figures. Note that the arm portion 31 can be said to be provided so as to protrude in the radial direction of the body portion 103 as long as the positions of the cutting edge portion 42 provided at the tip of the arm portion 31 when extended and retracted are on the outer and inner sides in the radial direction, regardless of whether the positions match in the axial direction. As long as the arm portion 31 protrudes in the radial direction in this way, the cutting edge portion 42 may be displaced in the axial direction when extended or retracted.

[0028] Each arm 31 shown in the figure is configured by connecting two rod members 32, 33 with a bendable joint portion 34 provided therebetween. The two rod members 32, 33 are provided with an arm drive portion 35 as an actuator. When the arm 31 is configured in this way, the arm drive portion 35 drives the two rod members 32, 33 by moving them apart or approaching each other while bending the joint portion 34, thereby allowing the arm 31 to extend inward and outward in the radial direction of the body 103. The arm 31 that can extend inward and outward in the radial direction is advantageous in that the blade portion 41 can be displaced at a necessary time, such as when the cutting edge portion 42 of the blade portion 41 is pressed against the inner surface 102 of the reduction container 101 to remove deposits on the inner surface 102.

[0029] The arm driving unit 35 is preferably configured to include an air cylinder capable of driving the arm unit 31 so as to press the cutting edge portion 42 of the blade portion 41 against the inner surface 102 of the reduction container 101 with a constant pressure. This allows the cutting edge portion 42 to be pressed against the inner surface 102 with a constant pressure, and allows the adhering matter to be removed more effectively while suppressing damage to the inner surface 102. In addition, since the reduction reaction of titanium tetrachloride is performed under high temperature conditions, the reduction container 101 is exposed to an environment with a large temperature difference, such as from room temperature to high temperature or vice versa, and the inner surface 102 may be deformed. An example of such a deformation is that the inner surface 102 has a wavy shape. When the inner surface 102 is deformed, if each arm driving unit 35 is provided with a controllable air cylinder, each arm driving unit 35 can apply the same pressure to the deformed inner surface 102 while balancing each other, so that even if the inner surface 102 has a wavy shape, for example, the adhering matter on the inner surface 102 can be removed well. The air cylinder may be provided so as to enable each arm driving unit 35 to be controlled individually and independently.

[0030] The blade portion 41 may have any blade tip portion 42 suitable for rubbing against the inner surface 102 of the reduction container 101 and removing deposits therefrom. The illustrated blade portion 41 has a flat spatula shape with a thickness that gradually decreases and a width that gradually increases toward the blade tip portion 42 side, but is not limited thereto.

[0031] The length of the cutting edge portion 42 constituting the edge portion on the most distal end side of the blade portion 41 is preferably 50 mm to 150 mm, measured in the width direction along the shape of the cutting edge portion 42. When the length of the cutting edge portion 42 is 50 mm or more, the relatively large cutting edge portion 42 can efficiently remove deposits on the inner surface 102, so that removal of deposits can be completed in a short period of time. On the other hand, when the length of the cutting edge portion 42 is 150 mm or less, a relatively large force can be applied to the inner surface 102 by the not so large cutting edge portion 42, so that deposits can be easily removed.

[0032] It is preferable that the cutting edge portion 42 has a shape that is curved in the circumferential direction following the curved inner surface 102 of the reduction container 101. This is because the cutting edge portion 42 having a shape that matches the curved inner surface 102 can efficiently remove deposits on the inner surface 102. When the cutting edge portion 42 has a curved shape, the above-mentioned length of the cutting edge portion 42 is the length measured along the curved shape.

[0033] 7, the pressing angle θ between the cutting edge portion 42 and the inner surface 102 when the cutting edge portion 42 is pressed against the inner surface 102 of the reduction container 101, in other words, the angle θ between the inner surface 102 and the surface of the spatula-shaped portion of the blade 41 near the cutting edge portion 42, is preferably within the range of 30° to 45°. If the pressing angle θ is too small, the force acting from the cutting edge portion 42 to the inner surface 102 becomes small, and there is a risk that it becomes difficult to remove the deposit. On the other hand, if the pressing angle θ is too large, the cutting edge portion 42 may damage the inner surface 102 of the reduction container 101. In this case, when the reduction container 101 is used for a reduction reaction thereafter, there is a concern that the sponge titanium mass may be contaminated by the material of the reduction container 101 due to the damage to the inner surface 102.

[0034] In order to more easily remove deposits on the inner surface 102 of the reduction container 101, the blade unit 41 preferably includes a crushing mechanism 43 (such as an air breaker) that vibrates the cutting edge portion 42 to strike the inner surface 102. In the illustrated deposit removal device 1 (see FIGS. 1 to 6), the crushing mechanism 43 is attached to a rod member 33 located radially outward of the arm unit 31, and the cutting edge portion 42 is provided so as to protrude radially outward from the crushing mechanism 43.

[0035] To use the above-mentioned deposit removal device 1 (see Figs. 5 and 6) to remove deposits on the inner surface 102 of the reduction container 101, for example, the reduction container 101 is first placed in an upright position (an orientation in which the axial direction is oriented substantially in the vertical direction), and the deposit removal device 1 is installed over the opening 105 of the body 103 using a crane or the like, as shown in Fig. 4, and the container connection part 11 is attached to the opening 105. At this time, the telescopic shaft part 21 and the arm part 31 of the deposit removal device 1 can both be in a retracted state and stored in the container connection part 11.

[0036] Next, as shown in FIG. 5, the other end of the telescopic shaft portion 21 of the deposit removal device 1 above the opening 105 is extended downward, and the arm portion 31 and the blade portion 41 are positioned deep inside the reduction container 101.

[0037] 6, the joint portion 34 is bent by the arm drive unit 35 to open the rod members 32, 33, and the arm unit 31 is extended radially outward. This causes the cutting edge portion 42 of the blade unit 41 provided at the tip of the arm unit 31 to be pressed against the inner surface 102 of the reduction container 101. In the case where the arm unit 31 includes a crushing mechanism 43, when the crushing mechanism 43 is operated, the cutting edge portion 42 vibrates and strikes the inner surface 102 of the reduction container 101.

[0038] When the telescopic shaft portion 21 is contracted in this state, the blade tip portion 42 pressed against the inner surface 102 of the reduction container 101 is rubbed against the inner surface 102 in accordance with the telescopic movement. As a result, the deposits on the inner surface 102 are scraped off and removed by the blade tip portion 42.

[0039] After the telescopic shaft part 21 is extended and retracted to rub the cutting edge part 42 against the inner surface 102 in the axial direction, the telescopic shaft part 21 is rotated to change the circumferential position on the inner surface 102 of the reduction container 101 where the cutting edge part 42 is pressed. Then, the cutting edge part 42 is pressed against the inner surface 102 at a position slightly shifted from the position where the cutting edge part 42 was previously rubbed against the inner surface 102 in the axial direction in the circumferential direction of the inner surface 102, and the telescopic shaft part 21 is extended in this state, whereby the cutting edge part 42 is rubbed against the inner surface 102 in the axial direction. In this way, the cutting edge part 42 is reciprocated in the axial direction on the inner surface 102 while being pressed against the inner surface 102 while changing its circumferential position, whereby deposits can be removed. Alternatively, the cutting edge portion 42 may be pressed and rubbed against the inner surface 102 to change the circumferential position of the cutting edge portion 42 only during either the contracting or extending operation of the telescopic shaft portion 21, and the cutting edge portion 42 may be kept away from the inner surface 102 during the other operation, thereby removing adhesions in one direction.

[0040] As described above, by repeatedly pressing the cutting edge portion 42 against the inner surface 102 and extending and rotating the telescopic shaft portion 21, it is possible to remove deposits from many parts of the inner surface 102 of the reduction container 101.

[0041] In the above, the cutting edge portion 42 is pressed against and rubbed against the inner surface 102 during the extension and retraction of the telescopic shaft portion 21. However, the cutting edge portion 42 may be pressed against the inner surface 102 during the rotation of the telescopic shaft portion 21. In this case, the cutting edge portion 42 is rubbed against the inner surface 102 as the telescopic shaft portion 21 rotates, whereby any deposits on the inner surface 102 are removed in the circumferential direction.

[0042] The reduction vessel 101 from whose inner surface 102 deposits have been removed by the deposit removal device 1 can be reused for the reduction reaction of titanium tetrachloride.

[0043] (Method of manufacturing titanium sponge) The deposit removal device 1 (see Figs. 4 to 6) described above can be used for the reduction vessel 101 used in the reduction reaction of titanium tetrachloride.

[0044] In the reduction reaction of titanium tetrachloride, metallic magnesium (Mg) is stored in a molten state as a reducing agent in the reduction vessel 101, and the inside of the reduction vessel 101 becomes a molten bath. Then, while the reduction vessel 101 is heated in a reduction furnace and cooled locally, the raw material titanium tetrachloride (TiCl4) is supplied by dropping it onto the surface of the molten bath from above. The titanium tetrachloride dropped in this way comes into contact with the metallic magnesium in the molten bath and is reduced by the metallic magnesium based on the reaction: TiCl4 + 2Mg → Ti + 2MgCl2. The metallic titanium (Ti) produced by the reduction of titanium tetrachloride becomes a titanium sponge mass in the reduction vessel 101.

[0045] Magnesium chloride (MgCl2) produced in the molten bath as a by-product of this reaction settles below the bath surface due to its larger specific gravity than metallic magnesium. Meanwhile, metallic magnesium in the molten bath rises to the bath surface due to its relatively small specific gravity. This difference in specific gravity between magnesium chloride and metallic magnesium causes the bath to flow, and metallic magnesium is located at the bath surface. As a result, a reaction continues between metallic magnesium and the dripped titanium tetrachloride at the bath surface, and titanium sponge mass grows mainly in the molten bath. The magnesium chloride that settles below can be extracted from the bottom 104 of the reduction vessel 101 to the outside, for example, intermittently at regular intervals.

[0046] In the reduction reaction of titanium tetrachloride, magnesium chloride may be supplied through a pipe (not shown) connected to the bottom 104 side of the reduction vessel 101. The magnesium chloride used for supply may be that which is by-produced in the Kroll process.

[0047] The titanium tetrachloride to be subjected to the reduction reaction can be, for example, purified titanium tetrachloride in a liquid state after being refined in a rectification column. This purified titanium tetrachloride is obtained, for example, by refining crude titanium tetrachloride produced by reacting a raw material ore such as titanium ore with a carbon source such as coke and chlorine gas in a rectification column. However, the titanium tetrachloride is not limited to the above-mentioned purified titanium tetrachloride as long as it can be used in the reduction reaction.

[0048] In addition, the magnesium chloride produced by the reduction reaction can be decomposed into metallic magnesium and chlorine gas by subjecting it to molten salt electrolysis in an electrolytic cell. The metallic magnesium thus obtained can be reused in the reduction reaction.

[0049] After the reduction reaction is completed, a molten bath containing metallic magnesium not used in the reduction reaction (unreacted metallic magnesium) and magnesium chloride, a by-product produced in the reduction reaction, is stored in reduction vessel 101. In order to separate the titanium sponge lump from the molten bath, the molten bath can be discharged from reduction vessel 101 while leaving the titanium sponge lump in reduction vessel 101. Furthermore, the interior of reduction vessel 101 may then be heated under a reduced pressure atmosphere to separate the unreacted metallic magnesium remaining in reduction vessel 101 from the titanium sponge lump. The titanium sponge lump is then removed from reduction vessel 101.

[0050] Thereafter, the titanium sponge mass is removed from the reduction vessel 101 and crushed to produce titanium sponge of a predetermined size.

[0051] Furthermore, as described above, after titanium tetrachloride has been reduced, the contents of the reduction vessel 101, such as the molten bath and titanium sponge mass, are removed, and the deposits on the inner surface 102 (see FIGS. 5 and 6) can be removed by using the deposit removal device 1 of this embodiment. [Explanation of symbols]

[0052] 1 Deposit removal device 11 Container connection 12 pillars 13 Plate-shaped members 21 Telescopic shaft section 22a to 22c Cylindrical member 23 Power Source 31 Arm section 32, 33 Rod member 34 Joints 35 Arm drive unit 41 Blade section 42 Cutting edge 43 Crushing Mechanism 101 Reduction Container 102 Inside 103 Torso 104 Bottom 105 Opening 106 Flange part θ Pressing angle

Claims

1. 1. An apparatus for removing deposits on an inner surface of a reduction vessel used in a reduction reaction of titanium tetrachloride, the reduction vessel having a cylindrical body and a bottom sealing one axial side of the body, comprising: a container connection portion attached to an opening on the other axial side of the body portion; a telescopic shaft portion that is rotatably held on the container connection portion at one end side around the central axis of the body portion and that is telescopic at the other end side in the axial direction; an arm portion provided on the other end side of the telescopic shaft portion and protruding from the telescopic shaft portion toward an inner surface of the reduction container in a radial direction of the body portion; a blade portion provided at a tip of the arm portion and having a cutting edge portion that is pressed against an inner surface of the reduction container and rubbed against the inner surface as the telescopic shaft portion telescopically moves and / or rotates; A deposit removal device comprising:

2. The deposit removal device according to claim 1 , wherein the arm portion is provided at a plurality of intervals around the circumference of the telescopic shaft portion.

3. The arm portion has a bendable joint portion, The deposit removal device according to claim 1 , further comprising an arm drive unit that drives the arm unit to bend the joint portion and extend or retract the arm unit inward and outward in the radial direction.

4. 4. The deposit removal device according to claim 3, wherein the arm drive unit includes an air cylinder capable of driving the arm unit so as to press the cutting edge portion against the inner surface of the reduction container with a constant pressure.

5. The deposit removal device according to claim 1 , wherein the cutting edge portion has a curved shape that follows the curved inner surface of the reduction vessel.

6. 2. The deposit removal device according to claim 1, wherein the length of the blade tip is 50 mm to 150 mm.

7. 2. The deposit removal device according to claim 1, wherein the cutting edge portion is pressed against the inner surface of the reduction container at an angle within a range of 30° to 45° between the cutting edge portion and the inner surface of the reduction container.

8. 1. A method for removing deposits on an inner surface of a reduction vessel used in a reduction reaction of titanium tetrachloride, the reduction vessel having a cylindrical body and a bottom sealing an opening on one side in an axial direction of the body, comprising the steps of: A method for removing deposits, which uses the deposit removal device according to any one of claims 1 to 7.

9. With the cutting edge portion of the blade portion pressed against the inner surface of the reduction container, the telescopic shaft portion is extended and / or contracted in the axial direction to rub the cutting edge portion against the inner surface and remove any deposits on the inner surface in the axial direction; and Rotating the telescopic shaft portion to change a circumferential position at which the blade tip portion is pressed against the inner surface of the reduction container. The method for removing deposits according to claim 8 , comprising:

10. A method for producing titanium sponge by reducing titanium tetrachloride in a reduction vessel, comprising the steps of: A method for producing titanium sponge, comprising the steps of: applying the method for removing deposits as claimed in claim 8 to the inner surface of the reduction vessel from which the contents have been removed after reduction of titanium tetrachloride, the inner surface having deposits thereon.

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