EP1666615A1 - Method and apparatus for producing metal - Google Patents
Method and apparatus for producing metal Download PDFInfo
- Publication number
- EP1666615A1 EP1666615A1 EP04747490A EP04747490A EP1666615A1 EP 1666615 A1 EP1666615 A1 EP 1666615A1 EP 04747490 A EP04747490 A EP 04747490A EP 04747490 A EP04747490 A EP 04747490A EP 1666615 A1 EP1666615 A1 EP 1666615A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- molten salt
- metal
- chamber
- reduction
- chlorination
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
- C25C3/02—Electrolytic production, recovery or refining of metals by electrolysis of melts of alkali or alkaline earth metals
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B34/00—Obtaining refractory metals
- C22B34/10—Obtaining titanium, zirconium or hafnium
- C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
- C22B34/1263—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining metallic titanium from titanium compounds, e.g. by reduction
- C22B34/1268—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining metallic titanium from titanium compounds, e.g. by reduction using alkali or alkaline-earth metals or amalgams
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B34/00—Obtaining refractory metals
- C22B34/10—Obtaining titanium, zirconium or hafnium
- C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
- C22B34/129—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining metallic titanium from titanium compounds by dissociation, e.g. thermic dissociation of titanium tetraiodide, or by electrolysis or with the use of an electric arc
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B5/00—General methods of reducing to metals
- C22B5/02—Dry methods smelting of sulfides or formation of mattes
- C22B5/04—Dry methods smelting of sulfides or formation of mattes by aluminium, other metals or silicon
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/24—Halogens or compounds thereof
- C25B1/26—Chlorine; Compounds thereof
Definitions
- the present invention relates to a method for producing a metal by a direct oxide reduction process wherein a metal oxide is reduced with Ca to form a metal such as titanium, and to an apparatus for use in practicing the method.
- Fig. 1 is an illustration of a direct oxide reduction process known in the prior art.
- the Olson process described in United States Patent No. 2,845,386.
- a TiO 2 powder is charged to a molten salt containing CaCl 2 for the formation of Ti as a result of the reduction of TiO 2 with Ca, as shown in Fig. 1.
- CaO is electrolyzed in the molten salt containing CaCl 2 using an iron cathode and a graphite anode.
- CaO is formed as a byproduct on the surface of the TiO 2 powder with the progress of the reaction. Since, however, the byproduct CaO is soluble in CaCl 2 , the CaO formed on the surface of the TiO 2 powder is dissolved in the CaCl 2 and the reaction between TiO 2 and Ca progresses continuously on the surface of the TiO 2 powder. Further, upon electrolysis of the CaO-containing molten salt (CaCl 2 ), the CaO is removed from the CaCl 2 , as shown below by the chemical formulas (1)-(3).
- the byproduct CaO formed on the surface of the TiO 2 powder is dissolved in the CaCl 2 and, further, the dissolved CaO is continuously removed from the CaCl 2 as a result of electrolysis, hence is never accumulated.
- the reaction for the formation of Ti from TiO 2 thus continues.
- the Olson process can form Ti from TiO 2 continuously without allowing accumulation of the byproduct CaO.
- CaC 2 is formed in the molten salt as the electrolysis of CaO proceeds.
- the thus-formed CaC 2 deteriorates the quality of Ti by mixing Ti with TiC, as shown by the chemical formula (3) given above.
- the Olson process can form Ti continuously and is therefore efficient but Ti is contaminated with TiC resulting from the reaction of CaC 2 formed in the molten salt containing CaCl 2 with the progress of electrolysis of CaO.
- the deterioration in product quality due to contamination with carbon (C) becomes a critical problem in the production of metallic titanium and, therefore, any process based on direct oxide reduction process has not yet been put to practical use.
- the method for producing a metal according to the present invention comprises a reduction step in which a metal oxide is introduced into a CaCl 2 -based molten salt containing Ca for the formation of the corresponding metal by reduction of the metal oxide with Ca in the molten salt, a separation step in which the metal formed in the molten salt is separated from the molten salt, a chlorination step in which the molten salt after separation of the metal is subjected to chlorination treatment with chlorine gas to chlorinate the byproduct CaO in the molten salt, and an electrolysis step in which a part or the whole of the molten salt after chlorination treatment is electrolyzed to form Ca and chlorine from CaCl 2 and the thus-formed Ca or Ca-containing molten salt is recycled to the above-mentioned reduction step.
- the metal production apparatus comprises a reduction chamber in which a CaCl 2 -based molten salt containing Ca is held and a metal oxide introduced into the molten salt is reduced with Ca in the molten salt to obtain said metal, means for separating the metal formed in the molten salt from the molten salt, a chlorination chamber in which the molten salt after separation of the metal is held and the molten salt is subjected to chlorination treatment with chlorine gas for the chlorination of the byproduct CaO in the molten salt, an electrolysis chamber in which a part or the whole of the molten salt after chlorination treatment is held and the molten salt is electrolyzed to form Ca and chlorine from CaCl 2 , and means for transferring the thus-formed Ca or Ca-containing molten salt from the electrolysis chamber to the reduction chamber mentioned above.
- the desired product titanium is formed based on the reactions represented below by the chemical equations (4) - (6): TiO2 + 2 Ca ⁇ Ti + 2CaO (reduction step) (4) 2CaO + 2Cl 2 ⁇ 2CaCl 2 + O 2 (chlorination step) (5) CaCl 2 ⁇ Ca + Cl 2 (electrolysis step) (6)
- the titanium oxide introduced is reduced with Ca in the molten salt and, as a result, metallic titanium is continuously formed and CaO is formed as a byproduct. Therefore, the molten salt after reduction is composed of CaCl 2 , metallic titanium and the byproduct CaO.
- the separation step the metallic titanium formed in the molten salt is separated from the molten salt.
- the molten salt after separation of the metallic titanium is subjected to chlorination treatment with chlorine gas, whereby CaCl 2 is formed from the CaO formed as a byproduct of the reduction reaction.
- the molten salt after chlorination treatment is almost free of CaO and substantially comprises CaCl 2 alone.
- the molten salt substantially comprising CaCl 2 alone after chlorination treatment is partly or as a whole sent to the electrolysis step, in which Ca is formed in the molten salt by the electrolysis treatment.
- the CaCl 2 -based molten salt now containing Ca again after the electrolysis step is recycled to the reduction step. In this manner, continuous production of metallic titanium becomes possible.
- the present invention is based on a first and second characteristic feature.
- the first feature consists in carrying out the electrolysis outside the region of the reduction reaction.
- the second feature consists in chlorinating CaO in the molten salt prior to electrolysis.
- the present invention provides an advantage that no oxygen gas is formed although chlorine gas is formed on the anode in the electrolysis.
- graphite is used as the anode material.
- the generation of oxygen gas on the anode results in the generation of carbon dioxide.
- the Ca generated on the cathode side has a high reducing power and therefore reduces the metal oxide.
- carbon dioxide when it is present in the molten salt, forms CaC 2 , and this CaC 2 mixes the carbonized metal into the product metal and thereby deteriorates the quality of the product metal.
- the melting point of Ca is 848°C but when Ca is dissolved in the molten salt CaCl 2 , Ca can be dissolved therein even at 848°C or less. While the exact solubility varies depending on the dissolution temperature, Ca can be dissolved to a level of about 1.5% by weight relative to CaCl 2 , and CaO can be dissolved to a level of about 8.0% by weight relative to CaCl 2 .
- powdery, granular or lumpy titanium oxide is introduced into the molten salt.
- the metallic titanium separated from the molten salt after reduction is also powdery, granular or lumpy and wet with the molten salt. From the reduction efficiency viewpoint, the use of powdery titanium oxide as the raw material is desirable.
- the separation of metallic titanium in the separation step is effectively carried out in the manner of separation through settling or a physical method such as compacting.
- the reasonable amounting metallic titanium in bulk once separated and taken out by settling or compacting can be made up into ingots by any of the conventional melting methods, for example by the plasma melting method.
- either of a bottomless crucible or a bottomed crucible may be used as the crucible for melting.
- the use of the bottomless crucible makes it possible to carry out continuous casting.
- an efficient method to be employed comprises the step of carrying out the reduction step in a bottomed vessel, extracting, from the vessel bottom, the molten salt with the product metallic titanium suspended therein at a high concentration as resulting from still and static separation and, thereafter, separating the product metallic titanium from the molten salt by compacting together, for instance.
- the remaining molten salt is subjected to chlorination treatment, whereby the efficiency of utilization of the molten salt can be improved.
- the chlorination treatment can be carried out continuously and efficiently by bubbling chlorine gas into the molten salt.
- the oxygen constituent of the CaO is included in the metallic titanium in the step of melting and the oxygen concentration in the titanium increases.
- the electrolysis step Ca is generated on the cathode side, while chlorine gas is generated on the anode side.
- the Ca concentration in the Ca-containing CaCl 2 extracted from the cathode site in the electrolyzer increases, the reducing capacity in the reduction step can be increased accordingly.
- the excess Ca is suspended as a solid or dissociated and floated to the surface.
- the CaCl 2 with Ca suspended therein can be sent to the reduction step.
- the suspended portion of Ca is newly dissolved to serve to continue reducing reaction thereof.
- the solubility of Ca in CaCl 2 is low. Therefore, in cases where the CaCl 2 containing Ca dissolved therein is sent to the reduction step, it becomes necessary to cycle a large amount of CaCl 2 so that the predetermined reducing capacity may be secured. On the contrary, when molten Ca alone is transferred from the electrolysis step to the reduction step, it is unnecessary any more to cycle a large amount of CaCl 2 .
- the production apparatus of the present invention is an apparatus for producing a metal utilizing the above-mentioned production method of the present invention.
- the electrolysis chamber is desirably configured such that a partition wall is provided for separating the anode side and cathode side from each other.
- a partition wall By providing such a partition wall, it becomes possible to prevent the chlorine gas generated on the anode side from travelling into the cathode side and further prevent the Ca generated on the cathode side from returning to the anode side.
- a partition wall the use of a porous ceramic plate (diaphragm) is recommended.
- the chlorine gas generated on the anode side in the electrolysis chamber is used for bubbling in the chlorination step.
- the chlorination chamber may be integrated with the reduction chamber.
- the electrolysis chamber may be integrated with the reduction chamber together.
- integrate it is meant that another chamber is arranged next to a specific chamber; the partition wall for separating both chambers from each other may be provided or may not be provided. The case of no partition wall being provided is claimed as unification, which will be described later herein.
- the cathode side of the electrolysis chamber integrated with the reduction chamber can be unified with the reduction chamber by removing the partition wall separating both chambers from each other.
- This electrolysis chamber can be formed in a ring-like manner around the reduction chamber which has a cylindrical shape. More specifically, the system can comprise an outer cylinder serving as the anode as well and an inner cylinder serving as the cathode as well and allowing the passage of the molten salt, where the inside of the inner cylinder serves as the reduction chamber.
- Fig. 2 is a drawing explaining the configuration of a titanium production apparatus according to the first embodiment of the present invention.
- the apparatus comprises a tower-shaped reduction chamber 1 and a horizontal separation means 2 connected to the lower part of the chamber 1.
- a CaCl 2 -based molten salt containing Ca is contained in the reduction chamber 1, and the raw material titanium oxide (TiO 2 ) in the form of a powder is continuously introduced into the molten salt.
- the molten salt is extracted sideways from the lower part of the reduction chamber 1 by the separation means 2.
- a downward flow or current of the molten salt is formed in the reduction chamber 1. This molten salt flow promotes the above-mentioned settling and separation of the product Ti and byproduct CaO.
- the separation means 2 the molten salt abundant in product Ti and byproduct CaO, after flowing thereinto, is physically compressed by means of a perforated cylindrical screw 3 in a cylindrical body. This physical separation procedure makes it possible to squeeze out the molten salt from the product Ti and compact together said product Ti.
- the compacted porous product Ti is successively discharged from the separation means 2 and melted in a melting means 4.
- the product Ti separated from the molten salt by compression in the separation means 2 can be subjected to rinsing with a CaO-free molten salt containing CaCl 2 as a main component.
- This treatment is to prevent CaO from remaining in the product Ti since the retention of CaO therein results in an increased oxygen concentration in the step of melting due to the oxygen constituent in CaO being included in the metallic titanium.
- a CaO-free molten salt after chlorination treatment in a chlorination chamber 7, which is to be mentioned later herein, is used for rinsing to dissolve the CaO remaining in the product Ti in CaCl 2 , consequently removing the same from the product Ti.
- a plasma device is used in the melting means 4.
- the lumpy product Ti is melted in an inert atmosphere and the molten Ti is collected in a water-cooled primary mold 5.
- the molten Ti settles, while the molten salt floats to the surface.
- the molten Ti separated from the molten salt is allowed to flow into a water-cooled secondary mold 6 and thus is cast to give a Ti ingot.
- the Ti melted in the melting means 4 still contains a certain amount of the molten salt. Therefore, the molten Ti is once collected in the water-cooled primary mold 5, where the molten salt floats to the surface and can be separated. The molten salt separated is sent to a chlorination chamber 7, which is to be described later herein.
- the molten salt separated from the product Ti in the separation means 2 and the molten salt separated by floating in the water-cooled primary mold 5 are sent to the chlorination chamber 7. Since these molten salt portions contain the byproduct CaO in large amounts, chlorine gas is bubbled into the molten salt introduced into the chlorination chamber 7 to chlorinate the CaO in the molten salt. This chlorination of CaO converts the CaO contained in the molten salt to CaCl 2 , and a CaO-free molten salt substantially consisted CaCl 2 is formed.
- the above CaO-free molten salt is then sent to an electrolysis chamber 8. Part thereof is sent to the separation means 4 for rinsing treatment, as mentioned above.
- the electrolysis chamber 8 the molten salt introduced is electrolyzed by using a graphite anode and an iron cathode. Chlorine gas is generated on the anode side in the chamber and Ca is formed on the cathode side. In this way, a CaCl 2 -based molten salt containing Ca is formed.
- the CaO to be eliminated is chlorinated.
- the reduction chamber 1 requires a Ca-containing molten salt and, therefore, the Ca-containing molten salt formed in the electrolysis chamber 8 is sent to the reduction chamber 1. Thus, it is substantially unnecessary to supplement CaCl 2 and Ca from the outside source.
- the chlorine gas formed as a byproduct in the electrolysis chamber 8 is sent to the chlorination chamber for reuse.
- the anode side and cathode side are separated from each other by a porous partition wall 9.
- the molten salt sent from the chlorination chamber 7 is introduced into the anode side, and the Ca-containing molten salt is drawn out from the cathode side and sent to the reduction chamber 1. In this way, a flow from the anode side toward the cathode side is formed. As a result, the molten salt is inhibited from flowing backward from the cathode side to the anode side.
- the chlorine gas is also prevented from entering the cathode side from the anode side.
- Fig. 3 is a drawing explaining the configuration of a titanium production apparatus according to the second embodiment of the present invention.
- the second embodiment differs from the above-mentioned first embodiment as shown in Fig. 2 in that part of the molten salt after completion of the chlorination treatment in the chlorination chamber 7 is sent to the electrolysis chamber 8, while almost whole of the remaining molten salt is returned to the reduction chamber 1 and that the transfer of Ca from the electrolysis chamber 7 to the reduction chamber 1 is carried out in the form of a metal.
- the transfer of Ca in the metal form to the reduction chamber 1 may be combined with the method comprising the step of transferring Ca being dissolved in CaCl 2 .
- the molten salt from the chlorination chamber 7 is introduced into the anode side, and the Ca formed on the liquid surface on the cathode side, either alone or together with a certain amount of CaCl 2 , is sent to the reduction chamber 1.
- the Ca transferred to the reduction chamber 1 floats to the surface of the molten salt in the chamber and is dissolved in CaCl 2 . Therefore, the Ca concentration in the CaCl 2 in the reduction chamber 1 is maintained at a high level in spite of the fact that the amount of the molten salt or Ca transferred from the chlorination chamber 7 to the reduction chamber 1 via the electrolysis chamber 8 is small.
- Fig. 4 is a drawing explaining the configuration of a titanium production apparatus according to the third embodiment of the present invention.
- the third embodiment differs from the production apparatus according to the second embodiment as shown in Fig. 3, featured in that the chlorination chamber 7 is integrated with the reduction chamber 1. Otherwise, the configuration is substantially the same as that of the production apparatus according to the second embodiment.
- the chlorination chamber 7 is laterally disposed being annexed to the vertical type reduction chamber 1 via a partition wall 10.
- titanium oxide is introduced into the CaCl 2 -based molten salt within the chamber through a feeding tube 11 inserted into the CaCl 2 .
- the titanium formed from titanium oxide upon reduction with Ca in the CaCl 2 settles on the bottom of the reduction chamber 1 and downwardly extracted and sent to the lower separation means 2.
- the CaCl 2 containing the byproduct CaO flows from the lower part of the reduction chamber 1 into the chlorination chamber 7 and undergoes chlorination treatment with chlorine gas injected thereinto from a site at the lower part thereof, whereby CaO is chlorinated.
- the CaCl 2 rises through the chlorination chamber 7 together with the chlorine gas flow (gas lift) rising within the chlorination chamber 7.
- the CaCl 2 separated from the metallic titanium in the separation means 2 is also introduced into the lower part of the chlorination chamber.
- the oxygen gas formed as a byproduct in the chlorination chamber 7 is drawn out upwards.
- the Ca introduced into the reduction chamber 1 forms a layer covering over the CaCl 2 in the reduction chamber 1.
- the feeding tube 11 mentioned above serves for charging titanium oxide into the CaCl 2 through the Ca layer over the CaCl 2 .
- the transfer of CaCl 2 between both chambers becomes easy. It is also possible to transfer whole of the CaCl 2 coming out of the chlorination chamber 7 to the electrolysis chamber 8.
- Fig. 5 is a drawing explaining the configuration of a titanium production apparatus according to the fourth embodiment of the present invention.
- the electrolysis chamber 8 is further added to the integrated reduction chamber 1 in the fourth embodiment. Otherwise, the configuration is substantially the same as that of the production apparatus according to the third embodiment.
- the electrolysis chamber 8 is sideways disposed, as opposed to the chlorination chamber 7, having the reduction chamber 1 between them, and there is no partition wall provided between the reduction chamber and electrolysis chamber.
- the electrolysis chamber 8 is provided with a graphite anode 12 and an iron cathode 13, and the anode side is separated from the cathode side by a partition wall 9.
- the cathode side is located on the side of the reduction chamber 1 and unified with the reduction chamber 1 without any partition wall.
- the partition wall 9 is configured so that the molten salt can pass therethrough, like the case of the first embodiment.
- the CaCl 2 transferred from the chlorination chamber 7 is introduced into the anode side.
- the chlorine gas generated as a byproduct on the anode side is sent to the chlorination chamber 7.
- the CaCl 2 introduced into the anode side passes through the partition wall 9 and migrates to the cathode side.
- Ca is formed on the surface of the iron cathode 13, and the Ca thus formed migrates to the reduction chamber 1 side while floating to the surface being carried by the bath flow.
- the Ca reservoir 14 is a box-like body whose bottom is open. It catches up the Ca that is formed on the surface of the cathode 13 and migrates toward the reduction chamber 1 side, and thus prevents the same from being cropped out above the bath surface.
- the Ca collected in the Ca reservoir 14 is dissolved in the CaCl 2 in the reduction chamber 1 and used for the reduction reaction within the reduction chamber 1.
- the Ca reservoir 14 is made of iron, like the cathode 13, and it may be unified with the cathode 13 so that it can have the same potential as the cathode 13.
- the aim of providing the Ca reservoir 14 is to inhibit the Ca layer from being cropped out above the bath surface.
- the Ca layer may be cropped out above the bath surface.
- the Ca reservoir 14 is provided to avoid the formation of CaO as a result of oxidation as such.
- the upper part of the partition wall 9 is protruded toward the cathode 13 and is in contact with the cathode 13. This structure inhibits the Ca generated on the surface of the cathode 13 from staying between the cathode 13 and the partition wall 9.
- the transfer of Ca from the electrolysis chamber 8 to the reduction chamber 1 becomes easy.
- the cathode side where Ca is formed within the electrolysis chamber 8 can be unified with the reduction chamber 1 and therefore the partition wall between both the chambers can be eliminated. Therefore, the structure of the apparatus can be particularly simplified and the apparatus can be rendered small-sized.
- Fig. 6 is a drawing explaining the configuration of a titanium production apparatus according to the fifth embodiment of the present invention.
- the partition wall 9 in the electrolysis chamber 8 as found in the configuration of the production apparatus according to the fourth embodiment as shown in Fig. 6 has been eliminated.
- the other structural elements are substantially the same as those in the titanium production apparatus according to the fourth embodiment.
- the molten salt is introduced into the anode side, as mentioned above, so that a flow of the molten salt from the anode 12 side to the cathode 13 side is formed. Therefore, even when the partition wall 9 separating the anode side and cathode side from each other is omitted, the efficiency can be prevented from decreasing because of the reflux of the molten salt.
- the cathode 13, like the partition wall 9, has a structure such that the molten salt can pass therethrough.
- a curtain wall type partition wall 15 made of a chlorine gas-resistant material such as a refractory material. It may be conceived that the cathode 13 be lengthened beyond the liquid surface level in lieu of the newly provided partition wall 15. In this case, however, there arises the problem that the lengthened portion of the cathode 13 may be corroded by the chlorine gas generated on the anode side. Thus, it becomes necessary to provide the partition wall 15 separately from the cathode 13.
- the apparatus structure is still more simplified and can be reduced the size more.
- Fig. 7 is a drawing explaining the configuration of a titanium production apparatus according to the sixth embodiment of the present invention.
- Fig. 8 is a drawing explaining the cross-sectional configuration, seen along the line X-X, of the titanium production apparatus shown in Fig. 7.
- the sixth embodiment has a configuration such that the electrolysis chamber 8 is integrated with the reduction chamber 1.
- the reduction chamber 1 is formed like a cylinder and the electrolysis chamber 8 is formed like a cylinder surrounding the reduction chamber 1.
- the cylindrical electrolysis chamber 8 provided outside the reduction chamber 1 has a cylindrical anode 12 serving also as the outer wall and a cylindrical cathode 13 serving also as the inner wall. All of the CaO and the Ca-free CaCl 2 obtained in the chlorination chamber 7 positioned sideways to the reduction chamber 1 are introduced into the ring-like space between the anode 12 and cathode 13.
- the inside cathode 13 serves also as part of the cylindrical outer wall of the reduction chamber 1, and the inside thereof is unified with the reduction chamber 1.
- the cathode 13 in the sixth embodiment comprises a plurality of cathode segments arranged in a swirling manner in the circumferential direction, and there is provided a slit 13a between every two cathode segments 13.
- This slit 13a is configured so as to pass the molten salt from the outside to the inside and thus it has a shape such that the space thereof gradually increases from the inside toward the outside.
- This configuration of each slit 13a causes the formation of an internal swirling flow and external swirling flow on each side of the cathode 13 and, at the same time, it promotes the flow of the molten salt from the outside to the inside.
- a cylindrical partition wall 15 made of a chlorine gas-resistant material, for example a refractory material. For the same reason as in the fifth embodiment, it becomes necessary to provide the partition wall 15 in addition to the cathode 13.
- a swirling flow is generated on the external side of the cylindrical cathode 13 and, further, the molten salt flowing into the inside of the cathode 13, while swirling, comes down in the reduction chamber 1 and, thus, the Ca formed on the surface of the cathode 13 is smoothly drawn into the inside thereof.
- the Ca flowing into the inside of the cathode 13 floats to the surface above the CaCl 2 in the reduction chamber 1 and is dissolved in the CaCl 2 , and the dissolved Ca contributes to the reduction reaction in the reduction chamber 1.
- the electrolysis chamber 8 integrated with the reduction chamber 1 cylindrically and externally to the reduction chamber 1, it becomes possible to increase the areas of the anode 12 and cathode 13 in the electrolysis chamber 8. This enables more efficient apparatus designing. While, in the case described herein, the whole amount of the CaCl 2 obtained in the chlorination chamber 7 is introduced into the electrolysis chamber 8, it is also possible to introduce only a partial amount thereof into that chamber.
- the metal to be produced in accordance with the present invention includes not only titanium but also tungsten, niobium, tantalum, chromium, zirconium and neodymium.
- the electrolysis in the direct oxide reduction method comprising the step of reducing a metal oxide with Ca is carried out in a region outside the reduction area and the CaO is eliminated from the molten salt to be subjected to electrolysis, so that the problems encountered in the prior art of direct oxide reduction processes, namely the low productivity and the product quality deterioration due to contamination with carbon, can be avoided.
- the present invention thereby can greatly contribute to the practical use of the oxide reduction method in the field of metal production.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Metallurgy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Mechanical Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Manufacturing & Machinery (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Inorganic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Electrolytic Production Of Metals (AREA)
Abstract
The present invention relates to a method for producing a metal by a direct oxide reduction process with Ca. A CaCl2-based molten salt containing Ca is held in a reduction chamber 1, a metal oxide is introduced into the molten salt in the reduction chamber 1, and the metal oxide is reduced with the Ca in the molten salt to form said metal. The metal formed in the molten salt is separated from the molten salt in a separation means 2, and the molten salt deprived of the metal is introduced into a chlorination chamber 7 and subjected to chlorination treatment with chlorine gas to eliminate the byproduct CaO in the molten salt. The molten salt after chlorination treatment is introduced into an electrolysis chamber 8 and electrolyzed for the formation of Ca and chlorine from CaCl2, and the thus-formed Ca or Ca-containing molten salt is transferred from the electrolysis chamber 8 to the reduction chamber 1. The chlorine obtained in the electrolysis chamber 8 is used in the chlorination chamber 7. Thus, the present invention provides a metal production method and an apparatus wherein high levels of productivity are obtained and the product metal can be inhibited from carbon contamination due to CaO, without any generation of CO2 from the production process, while their being based on the direct oxide reduction process comprising the step of reducing a metal oxide with Ca.
Description
- The present invention relates to a method for producing a metal by a direct oxide reduction process wherein a metal oxide is reduced with Ca to form a metal such as titanium, and to an apparatus for use in practicing the method.
- It is the Kroll process that is a general method for the commercial production of metallic titanium. In this Kroll process, metallic titanium is produced via a reduction step and vacuum separation step. In the reduction step, titanium tetrachloride (TiCl4) in a reaction vessel is reduced with Mg, whereby titanium metal sponge is produced. In the vacuum separation step, the unreacted Mg and the byproduct magnesium chloride (MgCl2) are eliminated from the titanium metal sponge in the reaction vessel, whereby the product titanium is produced.
- In the production of metallic titanium by the Kroll process, high-purity products can be produced but the production cost becomes high, rendering the product price high. Therefore, it is a limitation of the Kroll process that it can produce only high-quality and highly-priced metallic titanium.
- On the other hand, the production of low-priced metallic titanium, though somewhat lower in purity, is demanded for use as structural members, for instance. In response to such a demand, works have been planned to develop a method for continuously producing metallic titanium relatively low in purity at low cost and, in line with above, direct oxide reduction processes consisting in reducing titanium oxide with Ca have been investigated.
- Fig. 1 is an illustration of a direct oxide reduction process known in the prior art. As a typical example of the known direct oxide reduction processes, there is the Olson process described in United States Patent No. 2,845,386. In this process, a TiO2 powder is charged to a molten salt containing CaCl2 for the formation of Ti as a result of the reduction of TiO2 with Ca, as shown in Fig. 1. At the same time, CaO is electrolyzed in the molten salt containing CaCl2 using an iron cathode and a graphite anode.
- In the Olson process mentioned above, CaO is formed as a byproduct on the surface of the TiO2 powder with the progress of the reaction. Since, however, the byproduct CaO is soluble in CaCl2, the CaO formed on the surface of the TiO2 powder is dissolved in the CaCl2 and the reaction between TiO2 and Ca progresses continuously on the surface of the TiO2 powder. Further, upon electrolysis of the CaO-containing molten salt (CaCl2), the CaO is removed from the CaCl2, as shown below by the chemical formulas (1)-(3).
- Thus, according to the Olson process, the byproduct CaO formed on the surface of the TiO2 powder is dissolved in the CaCl2 and, further, the dissolved CaO is continuously removed from the CaCl2 as a result of electrolysis, hence is never accumulated. The reaction for the formation of Ti from TiO2 thus continues.
-
2CaO + C → 2Ca + CO2 (on the anode surface) (1)
5Ca +2CO2 → CaC2 + 4CaO (in the vicinity of the anode) (2)
2Ti + CaC2 → 2TiC + Ca (on the catode) (3)
- As described above, the Olson process can form Ti from TiO2 continuously without allowing accumulation of the byproduct CaO. On the other hand, however, CaC2 is formed in the molten salt as the electrolysis of CaO proceeds. The thus-formed CaC2 deteriorates the quality of Ti by mixing Ti with TiC, as shown by the chemical formula (3) given above.
- In other words, the Olson process can form Ti continuously and is therefore efficient but Ti is contaminated with TiC resulting from the reaction of CaC2 formed in the molten salt containing CaCl2 with the progress of electrolysis of CaO. The deterioration in product quality due to contamination with carbon (C) becomes a critical problem in the production of metallic titanium and, therefore, any process based on direct oxide reduction process has not yet been put to practical use.
- It is an object of the present invention to provide a metal production method which is highly productive and free from such quality deterioration as contamination with carbon in spite of its employing the direct oxide reduction process featured by reducing a metal oxide with Ca, and a metal production apparatus for practicing such method.
- To accomplish the above object, the method for producing a metal according to the present invention comprises a reduction step in which a metal oxide is introduced into a CaCl2-based molten salt containing Ca for the formation of the corresponding metal by reduction of the metal oxide with Ca in the molten salt, a separation step in which the metal formed in the molten salt is separated from the molten salt, a chlorination step in which the molten salt after separation of the metal is subjected to chlorination treatment with chlorine gas to chlorinate the byproduct CaO in the molten salt, and an electrolysis step in which a part or the whole of the molten salt after chlorination treatment is electrolyzed to form Ca and chlorine from CaCl2 and the thus-formed Ca or Ca-containing molten salt is recycled to the above-mentioned reduction step.
- The metal production apparatus according to the present invention comprises a reduction chamber in which a CaCl2-based molten salt containing Ca is held and a metal oxide introduced into the molten salt is reduced with Ca in the molten salt to obtain said metal, means for separating the metal formed in the molten salt from the molten salt, a chlorination chamber in which the molten salt after separation of the metal is held and the molten salt is subjected to chlorination treatment with chlorine gas for the chlorination of the byproduct CaO in the molten salt, an electrolysis chamber in which a part or the whole of the molten salt after chlorination treatment is held and the molten salt is electrolyzed to form Ca and chlorine from CaCl2, and means for transferring the thus-formed Ca or Ca-containing molten salt from the electrolysis chamber to the reduction chamber mentioned above.
- In producing metallic titanium, for instance, by the metal production method of the present invention, the desired product titanium is formed based on the reactions represented below by the chemical equations (4) - (6):
TiO2 + 2 Ca → Ti + 2CaO (reduction step) (4)
2CaO + 2Cl2 → 2CaCl2 + O2 (chlorination step) (5)
CaCl2 → Ca + Cl2 (electrolysis step) (6)
- First, in the reduction step, the titanium oxide introduced is reduced with Ca in the molten salt and, as a result, metallic titanium is continuously formed and CaO is formed as a byproduct. Therefore, the molten salt after reduction is composed of CaCl2, metallic titanium and the byproduct CaO.
- Then, in the separation step, the metallic titanium formed in the molten salt is separated from the molten salt.
- Further, in the chlorination step, the molten salt after separation of the metallic titanium is subjected to chlorination treatment with chlorine gas, whereby CaCl2 is formed from the CaO formed as a byproduct of the reduction reaction. As a result, the molten salt after chlorination treatment is almost free of CaO and substantially comprises CaCl2 alone.
- The molten salt substantially comprising CaCl2 alone after chlorination treatment is partly or as a whole sent to the electrolysis step, in which Ca is formed in the molten salt by the electrolysis treatment. The CaCl2-based molten salt now containing Ca again after the electrolysis step is recycled to the reduction step. In this manner, continuous production of metallic titanium becomes possible.
- The present invention is based on a first and second characteristic feature. The first feature consists in carrying out the electrolysis outside the region of the reduction reaction. The second feature consists in chlorinating CaO in the molten salt prior to electrolysis. By combining these first and second features, it becomes possible to prevent the accumulation of CaO in the reduction step and at the same time prevent the generation of CaC2 otherwise resulting from electrolysis of CaO and thus avoid the carbon contamination of the product metal. Thus, it is possible to continue the reduction reaction while preventing the product from being contaminated.
- Furthermore, the present invention provides an advantage that no oxygen gas is formed although chlorine gas is formed on the anode in the electrolysis. In ordinary electrolytic processes, graphite is used as the anode material. As is indicated in Fig. 1 referring to the Olson process, the generation of oxygen gas on the anode results in the generation of carbon dioxide.
- In the electrolysis shown in Fig. 1, the Ca generated on the cathode side has a high reducing power and therefore reduces the metal oxide. However, as shown in the above chemical equations (2) and (3), carbon dioxide, when it is present in the molten salt, forms CaC2, and this CaC2 mixes the carbonized metal into the product metal and thereby deteriorates the quality of the product metal.
- On the contrary, no oxygen gas is generated on the graphite anode in the electrolysis according to the present invention and, as a result, no carbon dioxide is generated, hence there is no risk of carbon contamination of the product metal. In addition, now that the graphite anode is not consumed, stable electrolysis conditions can be secured.
- In the production process according to the present invention, it is necessary to control the molten salt temperature at the melting point (780°C) or more of CaCl2 in the reduction step, chlorination step and electrolysis step in which the molten salt is circulated. In this connection, the melting point of Ca is 848°C but when Ca is dissolved in the molten salt CaCl2, Ca can be dissolved therein even at 848°C or less. While the exact solubility varies depending on the dissolution temperature, Ca can be dissolved to a level of about 1.5% by weight relative to CaCl2, and CaO can be dissolved to a level of about 8.0% by weight relative to CaCl2.
- In the reduction step, powdery, granular or lumpy titanium oxide is introduced into the molten salt. The metallic titanium separated from the molten salt after reduction is also powdery, granular or lumpy and wet with the molten salt. From the reduction efficiency viewpoint, the use of powdery titanium oxide as the raw material is desirable.
- The separation of metallic titanium in the separation step is effectively carried out in the manner of separation through settling or a physical method such as compacting. The reasonable amounting metallic titanium in bulk once separated and taken out by settling or compacting can be made up into ingots by any of the conventional melting methods, for example by the plasma melting method.
- In the melting step, either of a bottomless crucible or a bottomed crucible may be used as the crucible for melting. The use of the bottomless crucible makes it possible to carry out continuous casting.
- When titanium oxide is introduced in the form of particles with small diameter, the formed metallic titanium also becomes small in diameter and, therefore, the separation through settling in the reduction step may become inefficient in some instances. In such cases, an efficient method to be employed comprises the step of carrying out the reduction step in a bottomed vessel, extracting, from the vessel bottom, the molten salt with the product metallic titanium suspended therein at a high concentration as resulting from still and static separation and, thereafter, separating the product metallic titanium from the molten salt by compacting together, for instance. The remaining molten salt is subjected to chlorination treatment, whereby the efficiency of utilization of the molten salt can be improved.
- In the chlorination step, the chlorination treatment can be carried out continuously and efficiently by bubbling chlorine gas into the molten salt.
- If CaO remains in the metallic titanium formed in the reduction step, the oxygen constituent of the CaO is included in the metallic titanium in the step of melting and the oxygen concentration in the titanium increases. For preventing this, it is desirable to insert the so-called rinsing step, namely the step of injecting CaO-free CaCl2 after chlorination treatment into an appropriate location during the separation step to thereby rinse the metallic titanium separated from the molten salt with the CaCl2 after chlorination treatment.
- Since up to about 8.0% by weight of CaO can be dissolved in CaCl2, as mentioned hereinabove, the CaO remaining in the metallic titanium is dissolved in the CaO-free CaCl2 that has been injected and thus is removed from the metallic titanium.
- In the electrolysis step, Ca is generated on the cathode side, while chlorine gas is generated on the anode side. As the Ca concentration in the Ca-containing CaCl2 extracted from the cathode site in the electrolyzer increases, the reducing capacity in the reduction step can be increased accordingly.
- In case the Ca concentration in the electrolyzer exceeds the solubility thereof in CaCl2, the excess Ca is suspended as a solid or dissociated and floated to the surface. The CaCl2 with Ca suspended therein can be sent to the reduction step. Upon consumption, in the reduction step, of the Ca originally being contained, the suspended portion of Ca is newly dissolved to serve to continue reducing reaction thereof.
- It is not always necessary to transfer the whole of the CaCl2 from the chlorination step to the electrolysis step. Only part thereof may be transferred. In that case, the remaining portion of CaCl2 may be directly sent from the chlorination step to the reduction step without subjecting to the electrolysis step. The reason why part of the CaCl2 is transferred from the chlorination step to the electrolysis step is as follows.
- The solubility of Ca in CaCl2 is low. Therefore, in cases where the CaCl2 containing Ca dissolved therein is sent to the reduction step, it becomes necessary to cycle a large amount of CaCl2 so that the predetermined reducing capacity may be secured. On the contrary, when molten Ca alone is transferred from the electrolysis step to the reduction step, it is unnecessary any more to cycle a large amount of CaCl2.
- When the Ca from the electrolysis step is stored on the melt surface in the reduction step, Ca is dissolved from the Ca layer formed on the liquid surface into the CaCl2 layer, whereby the Ca concentration in the CaCl2 layer can be increased. Thus, that portion of Ca consumed for the reduction of TiO2 by the dissolved Ca in the CaCl2 layer is supplemented by the dissolution of Ca from the Ca layer into the CaCl2 layer.
- The production apparatus of the present invention is an apparatus for producing a metal utilizing the above-mentioned production method of the present invention. In the production apparatus of the present invention, the electrolysis chamber is desirably configured such that a partition wall is provided for separating the anode side and cathode side from each other. By providing such a partition wall, it becomes possible to prevent the chlorine gas generated on the anode side from travelling into the cathode side and further prevent the Ca generated on the cathode side from returning to the anode side. In case of providing a partition wall, the use of a porous ceramic plate (diaphragm) is recommended.
- On the other hand, by continuously extracting the Ca-containing CaCl2 from the cathode side while continuously introducing the CaCl2 fed from the chlorination step into the anode side, it becomes possible to form a steady flow from the anode side to the cathode side. Once such a flow is formed, the same Ca separation effect as in case of using a porous plate can be expected by using a solid/non-porous plate being disposed below the liquid level and having an opening or hole(s) through which a small amount of the molten salt can pass, for example a slit metal plate, without using a porous plate as the partition wall.
- The chlorine gas generated on the anode side in the electrolysis chamber is used for bubbling in the chlorination step.
- For reducing the size of the apparatus, the chlorination chamber may be integrated with the reduction chamber. For the same purpose, it is also possible to integrate the electrolysis chamber with the reduction chamber together. By using the word "integrate" herein, it is meant that another chamber is arranged next to a specific chamber; the partition wall for separating both chambers from each other may be provided or may not be provided. The case of no partition wall being provided is touted as unification, which will be described later herein.
- The cathode side of the electrolysis chamber integrated with the reduction chamber can be unified with the reduction chamber by removing the partition wall separating both chambers from each other. This electrolysis chamber can be formed in a ring-like manner around the reduction chamber which has a cylindrical shape. More specifically, the system can comprise an outer cylinder serving as the anode as well and an inner cylinder serving as the cathode as well and allowing the passage of the molten salt, where the inside of the inner cylinder serves as the reduction chamber.
-
- Fig. 1 is a drawing explaining a direct oxide reduction method known in the art.
- Fig. 2 is a drawing explaining the configuration of a titanium production apparatus according to a first embodiment of the present invention.
- Fig. 3 is a drawing explaining the configuration of a titanium production apparatus according to a second embodiment of the present invention.
- Fig. 4 is a drawing explaining the configuration of a titanium production apparatus according to a third embodiment of the present invention.
- Fig. 5 is a drawing explaining the configuration of a titanium production apparatus according to a fourth embodiment of the present invention.
- Fig. 6 is a drawing explaining the configuration of a titanium production apparatus according to a fifth embodiment of the present invention.
- Fig. 7 is a drawing explaining the configuration of a titanium production apparatus according to a sixth embodiment of the present invention.
- Fig. 8 is a drawing explaining the cross-sectional configuration, seen from the direction of an arrow X-X, shown in Fig. 7.
- In the following, the first to sixth embodiments of the present invention are described referring to the drawings.
- Fig. 2 is a drawing explaining the configuration of a titanium production apparatus according to the first embodiment of the present invention. In the first embodiment, the apparatus comprises a tower-shaped
reduction chamber 1 and a horizontal separation means 2 connected to the lower part of thechamber 1. A CaCl2-based molten salt containing Ca is contained in thereduction chamber 1, and the raw material titanium oxide (TiO2) in the form of a powder is continuously introduced into the molten salt. - Thus, in the
reduction chamber 1, TiO2 charged into the molten salt is reduced by Ca in the molten salt and metallic titanium (Ti) is formed and, at the same time, CaO is formed as a byproduct. Both the product Ti and the byproduct CaO settle and are separated from the molten salt and flow into the separation means 2 together with a certain amount of CaCl2. - A CaCl2-based molten salt containing Ca, together with the raw material titanium oxide, is additionally supplied from the upper part to the
reduction chamber 1. On the other hand, the molten salt is extracted sideways from the lower part of thereduction chamber 1 by the separation means 2. As a result, a downward flow or current of the molten salt is formed in thereduction chamber 1. This molten salt flow promotes the above-mentioned settling and separation of the product Ti and byproduct CaO. - In the separation means 2, the molten salt abundant in product Ti and byproduct CaO, after flowing thereinto, is physically compressed by means of a perforated
cylindrical screw 3 in a cylindrical body. This physical separation procedure makes it possible to squeeze out the molten salt from the product Ti and compact together said product Ti. The compacted porous product Ti is successively discharged from the separation means 2 and melted in a melting means 4. - The product Ti separated from the molten salt by compression in the separation means 2 can be subjected to rinsing with a CaO-free molten salt containing CaCl2 as a main component. This treatment is to prevent CaO from remaining in the product Ti since the retention of CaO therein results in an increased oxygen concentration in the step of melting due to the oxygen constituent in CaO being included in the metallic titanium. More specifically, a CaO-free molten salt after chlorination treatment in a
chlorination chamber 7, which is to be mentioned later herein, is used for rinsing to dissolve the CaO remaining in the product Ti in CaCl2, consequently removing the same from the product Ti. - In the melting means 4, a plasma device is used. The lumpy product Ti is melted in an inert atmosphere and the molten Ti is collected in a water-cooled
primary mold 5. In the water-cooledprimary mold 5, the molten Ti settles, while the molten salt floats to the surface. The molten Ti separated from the molten salt is allowed to flow into a water-cooledsecondary mold 6 and thus is cast to give a Ti ingot. - In spite of its separation from the molten salt by compression in the separation means 2, the Ti melted in the melting means 4 still contains a certain amount of the molten salt. Therefore, the molten Ti is once collected in the water-cooled
primary mold 5, where the molten salt floats to the surface and can be separated. The molten salt separated is sent to achlorination chamber 7, which is to be described later herein. - The molten salt separated from the product Ti in the separation means 2 and the molten salt separated by floating in the water-cooled
primary mold 5 are sent to thechlorination chamber 7. Since these molten salt portions contain the byproduct CaO in large amounts, chlorine gas is bubbled into the molten salt introduced into thechlorination chamber 7 to chlorinate the CaO in the molten salt. This chlorination of CaO converts the CaO contained in the molten salt to CaCl2, and a CaO-free molten salt substantially consisted CaCl2 is formed. - The above CaO-free molten salt is then sent to an
electrolysis chamber 8. Part thereof is sent to the separation means 4 for rinsing treatment, as mentioned above. In theelectrolysis chamber 8, the molten salt introduced is electrolyzed by using a graphite anode and an iron cathode. Chlorine gas is generated on the anode side in the chamber and Ca is formed on the cathode side. In this way, a CaCl2-based molten salt containing Ca is formed. - In the
chlorination chamber 7, the CaO to be eliminated is chlorinated. On the other hand, thereduction chamber 1 requires a Ca-containing molten salt and, therefore, the Ca-containing molten salt formed in theelectrolysis chamber 8 is sent to thereduction chamber 1. Thus, it is substantially unnecessary to supplement CaCl2 and Ca from the outside source. The chlorine gas formed as a byproduct in theelectrolysis chamber 8 is sent to the chlorination chamber for reuse. - In this
electrolysis chamber 8, the anode side and cathode side are separated from each other by a porous partition wall 9. The molten salt sent from thechlorination chamber 7 is introduced into the anode side, and the Ca-containing molten salt is drawn out from the cathode side and sent to thereduction chamber 1. In this way, a flow from the anode side toward the cathode side is formed. As a result, the molten salt is inhibited from flowing backward from the cathode side to the anode side. The chlorine gas is also prevented from entering the cathode side from the anode side. - Fig. 3 is a drawing explaining the configuration of a titanium production apparatus according to the second embodiment of the present invention. The second embodiment differs from the above-mentioned first embodiment as shown in Fig. 2 in that part of the molten salt after completion of the chlorination treatment in the
chlorination chamber 7 is sent to theelectrolysis chamber 8, while almost whole of the remaining molten salt is returned to thereduction chamber 1 and that the transfer of Ca from theelectrolysis chamber 7 to thereduction chamber 1 is carried out in the form of a metal. In the second embodiment, however, the transfer of Ca in the metal form to thereduction chamber 1 may be combined with the method comprising the step of transferring Ca being dissolved in CaCl2. - Therefore, in the
electrolysis chamber 8, the molten salt from thechlorination chamber 7 is introduced into the anode side, and the Ca formed on the liquid surface on the cathode side, either alone or together with a certain amount of CaCl2, is sent to thereduction chamber 1. The Ca transferred to thereduction chamber 1 floats to the surface of the molten salt in the chamber and is dissolved in CaCl2. Therefore, the Ca concentration in the CaCl2 in thereduction chamber 1 is maintained at a high level in spite of the fact that the amount of the molten salt or Ca transferred from thechlorination chamber 7 to thereduction chamber 1 via theelectrolysis chamber 8 is small. - Considering that the solubility of Ca in CaCl2 is low, as mentioned above, part of the molten salt is transferred from the
chlorination chamber 7 to theelectrolysis chamber 8. In this way, the total production efficiency can be improved while avoiding the cycle involving a large amount of CaCl2. - Fig. 4 is a drawing explaining the configuration of a titanium production apparatus according to the third embodiment of the present invention. The third embodiment differs from the production apparatus according to the second embodiment as shown in Fig. 3, featured in that the
chlorination chamber 7 is integrated with thereduction chamber 1. Otherwise, the configuration is substantially the same as that of the production apparatus according to the second embodiment. - The
chlorination chamber 7 is laterally disposed being annexed to the verticaltype reduction chamber 1 via apartition wall 10. In thereduction chamber 7, titanium oxide is introduced into the CaCl2-based molten salt within the chamber through a feedingtube 11 inserted into the CaCl2. The titanium formed from titanium oxide upon reduction with Ca in the CaCl2 settles on the bottom of thereduction chamber 1 and downwardly extracted and sent to the lower separation means 2. - The CaCl2 containing the byproduct CaO flows from the lower part of the
reduction chamber 1 into thechlorination chamber 7 and undergoes chlorination treatment with chlorine gas injected thereinto from a site at the lower part thereof, whereby CaO is chlorinated. The CaCl2 rises through thechlorination chamber 7 together with the chlorine gas flow (gas lift) rising within thechlorination chamber 7. The CaCl2 separated from the metallic titanium in the separation means 2 is also introduced into the lower part of the chlorination chamber. On the other hand, the oxygen gas formed as a byproduct in thechlorination chamber 7 is drawn out upwards. - Most of the CaCl2 outgoing from the
chlorination chamber 7 is returned from the upper part of thechlorination chamber 7 to thereduction chamber 1. The remaining portion of CaCl2 is transferred to theelectrolysis chamber 8. In theelectrolysis chamber 8, Ca is formed from the CaCl2 thus introduced. The Ca formed in theelectrolysis chamber 8 is transferred, either alone or together with a small amount of the Ca-rich CaCl2, to thereduction chamber 1. The byproduct chlorine gas is sent to thechlorination chamber 7 for reuse. - The Ca introduced into the
reduction chamber 1 forms a layer covering over the CaCl2 in thereduction chamber 1. The feedingtube 11 mentioned above serves for charging titanium oxide into the CaCl2 through the Ca layer over the CaCl2. - In the titanium production apparatus comprising the
chlorination chamber 7 integrated with thereduction chamber 1, the transfer of CaCl2 between both chambers becomes easy. It is also possible to transfer whole of the CaCl2 coming out of thechlorination chamber 7 to theelectrolysis chamber 8. - Fig. 5 is a drawing explaining the configuration of a titanium production apparatus according to the fourth embodiment of the present invention. As compared with the production apparatus according to the third embodiment as shown in Fig. 4, the
electrolysis chamber 8 is further added to theintegrated reduction chamber 1 in the fourth embodiment. Otherwise, the configuration is substantially the same as that of the production apparatus according to the third embodiment. - The
electrolysis chamber 8 is sideways disposed, as opposed to thechlorination chamber 7, having thereduction chamber 1 between them, and there is no partition wall provided between the reduction chamber and electrolysis chamber. Theelectrolysis chamber 8 is provided with agraphite anode 12 and aniron cathode 13, and the anode side is separated from the cathode side by a partition wall 9. The cathode side is located on the side of thereduction chamber 1 and unified with thereduction chamber 1 without any partition wall. The partition wall 9 is configured so that the molten salt can pass therethrough, like the case of the first embodiment. - The CaCl2 transferred from the
chlorination chamber 7 is introduced into the anode side. The chlorine gas generated as a byproduct on the anode side is sent to thechlorination chamber 7. The CaCl2 introduced into the anode side passes through the partition wall 9 and migrates to the cathode side. Thus, to let the molten salt pass through the partition wall 9, there is formed, in theelectrolysis chamber 8, a bath flow from theanode 12 side to thecathode 13 side with the supply of the molten salt to the anode side. - On the cathode side of the
electrolysis chamber 8, Ca is formed on the surface of theiron cathode 13, and the Ca thus formed migrates to thereduction chamber 1 side while floating to the surface being carried by the bath flow. In the vicinity of the bath surface from thecathode 13 to thereduction chamber 1 side, there is provided aCa reservoir 14. TheCa reservoir 14 is a box-like body whose bottom is open. It catches up the Ca that is formed on the surface of thecathode 13 and migrates toward thereduction chamber 1 side, and thus prevents the same from being cropped out above the bath surface. The Ca collected in theCa reservoir 14 is dissolved in the CaCl2 in thereduction chamber 1 and used for the reduction reaction within thereduction chamber 1. - In the fourth embodiment, the
Ca reservoir 14 is made of iron, like thecathode 13, and it may be unified with thecathode 13 so that it can have the same potential as thecathode 13. The aim of providing theCa reservoir 14 is to inhibit the Ca layer from being cropped out above the bath surface. In case that the space above the liquid surface on the reduction chamber side from thecathode 13 can be filled with an inert gas atmosphere, the Ca layer may be cropped out above the bath surface. However, in case the ingress of air is unavoidable for some or other operational reasons, the Ca layer cropping out above the bath surface leads to the formation of CaO by oxidation. In this regard, theCa reservoir 14 is provided to avoid the formation of CaO as a result of oxidation as such. - Further, in the fourth embodiment, the upper part of the partition wall 9 is protruded toward the
cathode 13 and is in contact with thecathode 13. This structure inhibits the Ca generated on the surface of thecathode 13 from staying between thecathode 13 and the partition wall 9. - In the titanium production apparatus in which the
electrolysis chamber 8 is integrated with thereduction chamber 1, the transfer of Ca from theelectrolysis chamber 8 to thereduction chamber 1 becomes easy. In particular, the cathode side where Ca is formed within theelectrolysis chamber 8 can be unified with thereduction chamber 1 and therefore the partition wall between both the chambers can be eliminated. Therefore, the structure of the apparatus can be particularly simplified and the apparatus can be rendered small-sized. - Fig. 6 is a drawing explaining the configuration of a titanium production apparatus according to the fifth embodiment of the present invention. In the configuration according to the fifth embodiment, the partition wall 9 in the
electrolysis chamber 8 as found in the configuration of the production apparatus according to the fourth embodiment as shown in Fig. 6 has been eliminated. The other structural elements are substantially the same as those in the titanium production apparatus according to the fourth embodiment. - In the
electrolysis chamber 8 unified with thereduction chamber 1, the molten salt is introduced into the anode side, as mentioned above, so that a flow of the molten salt from theanode 12 side to thecathode 13 side is formed. Therefore, even when the partition wall 9 separating the anode side and cathode side from each other is omitted, the efficiency can be prevented from decreasing because of the reflux of the molten salt. However, thecathode 13, like the partition wall 9, has a structure such that the molten salt can pass therethrough. - Above the
cathode 13, however, there is provided a curtain walltype partition wall 15 made of a chlorine gas-resistant material such as a refractory material. It may be conceived that thecathode 13 be lengthened beyond the liquid surface level in lieu of the newly providedpartition wall 15. In this case, however, there arises the problem that the lengthened portion of thecathode 13 may be corroded by the chlorine gas generated on the anode side. Thus, it becomes necessary to provide thepartition wall 15 separately from thecathode 13. - By omitting the partition wall 9 separating the anode side and cathode side from each other in the
electrolysis chamber 8 according to the fifth embodiment, the apparatus structure is still more simplified and can be reduced the size more. On the other hand, there is no Ca reservoir on the reduction chamber side of thecathode 13 and, therefore, it is necessary to control the space above the liquid surface level on the reduction chamber side of thecathode 13 with an inert gas atmosphere. - Fig. 7 is a drawing explaining the configuration of a titanium production apparatus according to the sixth embodiment of the present invention. Fig. 8 is a drawing explaining the cross-sectional configuration, seen along the line X-X, of the titanium production apparatus shown in Fig. 7.
Like the fourth and fifth embodiments, the sixth embodiment has a configuration such that theelectrolysis chamber 8 is integrated with thereduction chamber 1. However, it has a configuration such that thereduction chamber 1 is formed like a cylinder and theelectrolysis chamber 8 is formed like a cylinder surrounding thereduction chamber 1. - The
cylindrical electrolysis chamber 8 provided outside thereduction chamber 1 has acylindrical anode 12 serving also as the outer wall and acylindrical cathode 13 serving also as the inner wall. All of the CaO and the Ca-free CaCl2 obtained in thechlorination chamber 7 positioned sideways to thereduction chamber 1 are introduced into the ring-like space between theanode 12 andcathode 13. Theinside cathode 13 serves also as part of the cylindrical outer wall of thereduction chamber 1, and the inside thereof is unified with thereduction chamber 1. - As shown in Fig. 8, the
cathode 13 in the sixth embodiment comprises a plurality of cathode segments arranged in a swirling manner in the circumferential direction, and there is provided aslit 13a between every twocathode segments 13. Thisslit 13a is configured so as to pass the molten salt from the outside to the inside and thus it has a shape such that the space thereof gradually increases from the inside toward the outside. This configuration of eachslit 13a causes the formation of an internal swirling flow and external swirling flow on each side of thecathode 13 and, at the same time, it promotes the flow of the molten salt from the outside to the inside. - Above the
cathode 13, as a continuum, there is provided acylindrical partition wall 15 made of a chlorine gas-resistant material, for example a refractory material. For the same reason as in the fifth embodiment, it becomes necessary to provide thepartition wall 15 in addition to thecathode 13. - In the sixth embodiment, a swirling flow is generated on the external side of the
cylindrical cathode 13 and, further, the molten salt flowing into the inside of thecathode 13, while swirling, comes down in thereduction chamber 1 and, thus, the Ca formed on the surface of thecathode 13 is smoothly drawn into the inside thereof. The Ca flowing into the inside of thecathode 13 floats to the surface above the CaCl2 in thereduction chamber 1 and is dissolved in the CaCl2, and the dissolved Ca contributes to the reduction reaction in thereduction chamber 1. - By configuring the
electrolysis chamber 8 integrated with thereduction chamber 1 cylindrically and externally to thereduction chamber 1, it becomes possible to increase the areas of theanode 12 andcathode 13 in theelectrolysis chamber 8. This enables more efficient apparatus designing. While, in the case described herein, the whole amount of the CaCl2 obtained in thechlorination chamber 7 is introduced into theelectrolysis chamber 8, it is also possible to introduce only a partial amount thereof into that chamber. - Although the cases of metallic titanium production have been described hereinabove, the metal to be produced in accordance with the present invention includes not only titanium but also tungsten, niobium, tantalum, chromium, zirconium and neodymium.
- In accordance with the metal production method and metal production apparatus of the present invention, the electrolysis in the direct oxide reduction method comprising the step of reducing a metal oxide with Ca is carried out in a region outside the reduction area and the CaO is eliminated from the molten salt to be subjected to electrolysis, so that the problems encountered in the prior art of direct oxide reduction processes, namely the low productivity and the product quality deterioration due to contamination with carbon, can be avoided. The present invention thereby can greatly contribute to the practical use of the oxide reduction method in the field of metal production.
Claims (19)
- A method for producing a metal which comprises:a reduction step in which a metal oxide is introduced into a CaCl2-based molten salt containing Ca for the formation of said metal by reduction of the metal oxide with Ca in the molten salt;a separation step in which said metal formed in the molten salt is separated from the molten salt;a chlorination step in which the molten salt after separation of said metal is subjected to chlorination treatment with chlorine gas to chlorinate the byproduct CaO in the molten salt; andan electrolysis step in which the molten salt after chlorination treatment is electrolyzed to form Ca and chlorine from CaCl2, and the thus-formed Ca or Ca-containing molten salt is sent to the above-mentioned reduction step.
- A method for producing a metal which comprises:a reduction step in which a metal oxide is introduced into a CaCl2-based molten salt containing Ca for the formation of said metal by reduction of the metal oxide with Ca in the molten salt;a separation step in which the metal formed in the molten salt is separated from the molten salt;a chlorination step in which the molten salt after separation of said metal is subjected to chlorination treatment with chlorine gas to chlorinate the byproduct CaO in the molten salt; andan electrolysis step in which the molten salt after chlorination treatment is electrolyzed to form Ca and chlorine from CaCl2, and the thus-formed Ca or Ca-containing molten salt is sent to the above-mentioned reduction step,wherein, in said reduction step, the metal formed is allowed to settle and the metal that has settled is drawn out together with the molten salt and transferred to the separation step.
- A method for producing a metal according to claim 1 or 2, wherein said metal is one of titanium, tungsten, niobium, tantalum, chromium, zirconium and neodymium.
- A method for producing a metal according to claim 1 or 2, wherein part of the molten salt after chlorination treatment is sent to the electrolysis step and the remaining portion of the molten salt is sent to the reduction step.
- A method for producing a metal according to claim 1 or 2, wherein the chlorine gas formed in said electrolysis step is used in said chlorination step.
- A method for producing a metal according to claim 1 or 2, wherein, in said electrolysis step, an electrolysis chamber in which the anode side and cathode side are separated from each other by a partition wall is used.
- A method for producing a metal according to claim 6, wherein a flow of the molten salt from the anode side toward the cathode side is formed in the electrolysis chamber.
- A method for producing a metal according to claim 1 or 2, further comprising the step of rinsing the metal separated from the molten salt using part of the CaCl2 after completion of said chlorination step.
- A method for producing a metal according to claim 1 or 2, wherein, in said separation step, said metal is separated from the molten salt by physical compacting together.
- A method for producing a metal according to claim 1 or 2, further comprising the step of melting the metal obtained in the separation step in an inert atmosphere to make an ingot.
- An apparatus for producing a metal comprising:a reduction chamber in which a CaCl2-based molten salt containing Ca is held and a metal oxide introduced into the molten salt is reduced with Ca in the molten salt to obtain said metal;means for separating the metal formed in the molten salt from the molten salt;a chlorination chamber in which the molten salt after separation of the metal is held and the molten salt is subjected to chlorination treatment with chlorine gas for the chlorination of the byproduct CaO in the molten salt;an electrolysis chamber in which the molten salt after chlorination treatment is held and the molten salt is electrolyzed to form Ca and chlorine from CaCl2; andmeans for transferring the thus-formed Ca or Ca-containing molten salt from the electrolysis chamber to said reduction chamber.
- An apparatus for producing a metal comprising:a reduction chamber in which a CaCl2-based molten salt containing Ca is held and a metal oxide introduced into the molten salt is reduced with Ca in the molten salt to obtain said metal;means for separating the metal formed in the molten salt from the molten salt;a chlorination chamber in which the molten salt after separation of the metal is held and the molten salt is subjected to chlorination treatment with chlorine gas for the chlorination of the byproduct CaO in the molten salt;an electrolysis chamber in which the molten salt after chlorination treatment is held and the molten salt is electrolyzed to form Ca and chlorine from CaCl2; andmeans for transferring the thus-formed Ca or Ca-containing molten salt from the electrolysis chamber to said reduction chamber,wherein said chlorination chamber is unified with said reduction chamber.
- An apparatus for producing a metal comprising:a reduction chamber in which a CaCl2-based molten salt containing Ca is held and a metal oxide introduced into the molten salt is reduced with Ca in the molten salt to obtain said metal;means for separating the metal formed in the molten salt from the molten salt;a chlorination chamber in which the molten salt after separation of the metal is held and the molten salt is subjected to chlorination treatment with chlorine gas for the chlorination of the byproduct CaO in the molten salt;an electrolysis chamber in which the molten salt after chlorination treatment is held and the molten salt is electrolyzed to form Ca and chlorine from CaCl2; andmeans for transferring the thus-formed Ca or Ca-containing molten salt from the electrolysis chamber to said reduction chamber,wherein said electrolysis chamber is integrated with said reduction chamber.
- An apparatus for producing a metal according to any of claims 11-13, wherein said electrolysis chamber has, between the anode side and cathode side, a partition wall through which the molten salt can pass.
- An apparatus for producing a metal according to claim 13, wherein the cathode side of said electrolysis chamber is unified with said reduction chamber.
- An apparatus for producing a metal according to claim 15, wherein said electrolysis chamber is configured in such a manner that the molten salt introduced into the anode side can flow through the cathode to the reduction chamber.
- An apparatus for producing a metal according to claim 16, further comprising a Ca reservoir for retaining Ca in the liquid on the reduction chamber side from the cathode.
- An apparatus for producing a metal according to claim 15, wherein said electrolysis chamber is formed like a ring surrounding the reduction chamber which has a cylindrical shape.
- An apparatus for producing a metal according to claim 18, wherein said electrolysis chamber comprises an outer cylinder serving also as the anode and an inner cylinder serving also as the cathode and allowing the molten salt to pass therethrough, the inside of said inner cylinder being the reduction chamber.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2003304176A JP4193984B2 (en) | 2003-08-28 | 2003-08-28 | Metal manufacturing equipment |
PCT/JP2004/010024 WO2005021809A1 (en) | 2003-08-28 | 2004-07-14 | Method and apparatus for producing metal |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1666615A1 true EP1666615A1 (en) | 2006-06-07 |
Family
ID=34269262
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP04747490A Withdrawn EP1666615A1 (en) | 2003-08-28 | 2004-07-14 | Method and apparatus for producing metal |
Country Status (4)
Country | Link |
---|---|
US (1) | US20060219053A1 (en) |
EP (1) | EP1666615A1 (en) |
JP (1) | JP4193984B2 (en) |
WO (1) | WO2005021809A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109295309A (en) * | 2018-09-25 | 2019-02-01 | 内蒙古扎鲁特旗鲁安矿业有限公司 | A kind of method that beryllium chloride reduction prepares metallic beryllium |
US10280527B2 (en) | 2012-09-13 | 2019-05-07 | Ge-Hitachi Nuclear Energy Americas Llc | Methods of fabricating metallic fuel from surplus plutonium |
CN111349788A (en) * | 2020-04-07 | 2020-06-30 | 厦门钨业股份有限公司 | Method for recycling tungsten from scheelite smelting slag |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090101517A1 (en) * | 2005-03-29 | 2009-04-23 | Kazuo Takemura | Method for Producing Ti or Ti Alloy, and Pulling Electrolysis Method Applicable Thereto |
AU2006240896A1 (en) * | 2005-04-25 | 2006-11-02 | Toho Titanium Co., Ltd. | Molten salt electrolytic cell and process for producing metal using the same |
JP2007063585A (en) * | 2005-08-30 | 2007-03-15 | Sumitomo Titanium Corp | MOLTEN SALT ELECTROLYSIS METHOD, ELECTROLYTIC CELL, AND METHOD FOR PRODUCING Ti BY USING THE SAME |
JPWO2008038405A1 (en) * | 2006-09-28 | 2010-01-28 | 東邦チタニウム株式会社 | Molten salt electrolytic cell for metal production and method for producing metal using the same |
JP5336193B2 (en) * | 2006-11-02 | 2013-11-06 | 株式会社三徳 | Method for producing metallic lithium |
PL2109691T3 (en) * | 2007-01-22 | 2017-02-28 | Materials And Electrochemical Research Corporation | Metallothermic reduction of in-situ generated titanium chloride |
CN104109757B (en) * | 2014-08-06 | 2016-03-30 | 中国原子能科学研究院 | A kind of technique recycling calciothermic reduction fused salt used |
CN109628731B (en) * | 2019-01-31 | 2020-09-04 | 河钢股份有限公司承德分公司 | Method for extracting and preparing vanadium and alloy powder by short-process treatment of vanadium-containing raw material |
CN112410589A (en) * | 2020-11-30 | 2021-02-26 | 包头稀土研究院 | Treatment method of rare earth sulfate roasted ore |
CN113234935B (en) * | 2021-05-10 | 2022-04-01 | 北京科技大学 | Method for co-extracting vanadium, titanium and chromium from vanadium slag |
CN113881975A (en) * | 2021-10-19 | 2022-01-04 | 杭州嘉悦智能设备有限公司 | Fused salt chlorination electrolytic furnace and control method thereof |
Family Cites Families (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2845386A (en) * | 1954-03-16 | 1958-07-29 | Du Pont | Production of metals |
US4617098A (en) * | 1982-08-31 | 1986-10-14 | Rhone-Poulenc Specialites Chimiques | Continuous electrolysis of lithium chloride into lithium metal |
CA2012009C (en) * | 1989-03-16 | 1999-01-19 | Tadashi Ogasawara | Process for the electrolytic production of magnesium |
US5439563A (en) * | 1993-08-25 | 1995-08-08 | Alcan International Limited | Electrolytic production of magnesium metal with feed containing magnesium chloride ammoniates |
JP3607532B2 (en) * | 1999-06-03 | 2005-01-05 | 住友チタニウム株式会社 | Deoxygenation method for titanium material |
JP2002129250A (en) * | 2000-10-30 | 2002-05-09 | Katsutoshi Ono | Method for producing metallic titanium |
JP2003129268A (en) * | 2001-10-17 | 2003-05-08 | Katsutoshi Ono | Method for smelting metallic titanium and smelter therefor |
JP4100080B2 (en) * | 2002-07-23 | 2008-06-11 | 住友金属工業株式会社 | Lithium silicate lubricated steel strip |
JP2004156130A (en) * | 2002-09-11 | 2004-06-03 | Sumitomo Titanium Corp | Titanium oxide porous sintered compact for production of metal titanium by direct electrolysis process, and its manufacturing method |
JP4198434B2 (en) * | 2002-10-09 | 2008-12-17 | 勝敏 小野 | Method for smelting titanium metal |
JP4395386B2 (en) * | 2003-10-10 | 2010-01-06 | 株式会社大阪チタニウムテクノロジーズ | Method for producing Ti or Ti alloy by circulating Ca source |
AU2004280401C1 (en) * | 2003-10-10 | 2008-12-11 | Osaka Titanium Technologies Co., Ltd | Method for producing Ti or Ti alloy through reduction by Ca |
JP4342413B2 (en) * | 2004-02-20 | 2009-10-14 | 株式会社大阪チタニウムテクノロジーズ | Method for producing Ti or Ti alloy by Ca reduction |
JP2005264320A (en) * | 2004-02-20 | 2005-09-29 | Sumitomo Titanium Corp | PROCESS FOR PRODUCING Ti OR Ti ALLOY BY REDUCTION OF Ca |
JP4347089B2 (en) * | 2004-03-01 | 2009-10-21 | 株式会社大阪チタニウムテクノロジーズ | Method for producing Ti or Ti alloy by Ca reduction |
JP4247792B2 (en) * | 2004-10-12 | 2009-04-02 | 東邦チタニウム株式会社 | Method and apparatus for producing metal by molten salt electrolysis |
JP2006124813A (en) * | 2004-11-01 | 2006-05-18 | Sumitomo Titanium Corp | METHOD AND APPARATUS FOR PRODUCING Ti BY Ca REDUCTION |
-
2003
- 2003-08-28 JP JP2003304176A patent/JP4193984B2/en not_active Expired - Fee Related
-
2004
- 2004-07-14 US US10/569,602 patent/US20060219053A1/en not_active Abandoned
- 2004-07-14 WO PCT/JP2004/010024 patent/WO2005021809A1/en active Application Filing
- 2004-07-14 EP EP04747490A patent/EP1666615A1/en not_active Withdrawn
Non-Patent Citations (1)
Title |
---|
See references of WO2005021809A1 * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10280527B2 (en) | 2012-09-13 | 2019-05-07 | Ge-Hitachi Nuclear Energy Americas Llc | Methods of fabricating metallic fuel from surplus plutonium |
CN109295309A (en) * | 2018-09-25 | 2019-02-01 | 内蒙古扎鲁特旗鲁安矿业有限公司 | A kind of method that beryllium chloride reduction prepares metallic beryllium |
CN111349788A (en) * | 2020-04-07 | 2020-06-30 | 厦门钨业股份有限公司 | Method for recycling tungsten from scheelite smelting slag |
CN111349788B (en) * | 2020-04-07 | 2021-12-17 | 厦门钨业股份有限公司 | Method for recycling tungsten from scheelite smelting slag |
Also Published As
Publication number | Publication date |
---|---|
US20060219053A1 (en) | 2006-10-05 |
WO2005021809A1 (en) | 2005-03-10 |
JP2005068539A (en) | 2005-03-17 |
JP4193984B2 (en) | 2008-12-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP1445350B1 (en) | Method and apparatus for smelting titanium metal | |
EP1666615A1 (en) | Method and apparatus for producing metal | |
EP1333110B1 (en) | Fabrication of metal articles by electrolysis of preshaped metal compounds in a fused salt | |
JP5183498B2 (en) | Electrolytic production of silicon and scouring method | |
JP2005068539A5 (en) | ||
US20090152122A1 (en) | Method for electrolyzing molten salt, electrolytic cell, and process for producing ti using said method | |
US7648560B2 (en) | Method for producing Ti or Ti alloy through reduction by Ca | |
JP2003306725A (en) | Method for producing titanium, method for producing pure metal and apparatus for producing pure metal | |
US20100089204A1 (en) | Process for Producing Ti and Apparatus Therefor | |
US2917440A (en) | Titanium metal production | |
US20090114546A1 (en) | Method for Removing/Concentrating Metal-Fog-Forming Metal Present in Molten Salt, Apparatus Thereof, and Process and Apparatus for Producing Ti or Ti Alloy by use of them | |
JP4193985B2 (en) | Metal production method and apparatus by Ca reduction | |
JP3981601B2 (en) | Titanium metal refining method and refining apparatus | |
CN101151383A (en) | Process for producing Ti or Ti alloy, and pull-up electrolysis method applicable to said process | |
US4686025A (en) | Apparatus for the production of a metal by electrolyzing halides in a molten salt bath, by a simultaneous continuous double deposit | |
JP4513297B2 (en) | Metal oxide reduction method and metal oxide reduction apparatus | |
JP4249685B2 (en) | Method for producing Ti by Ca reduction | |
JP2005133196A (en) | METHOD OF PRODUCING Ti OR Ti ALLOY THROUGH CIRCULATION OF MOLTEN SALT | |
JP4227113B2 (en) | Pull-up electrolysis method | |
Rosenberg | Prospects for Cost Reduction of Titanium via Electrolysis | |
JP2003328052A (en) | Methof for manufacturing sponge titanium | |
JPH0532452B2 (en) |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20060328 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR |
|
DAX | Request for extension of the european patent (deleted) | ||
RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: OSAKA TITANIUM TECHNOLOGIES CO., LTD. |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
|
18W | Application withdrawn |
Effective date: 20090216 |