US2848397A - Electrolytic production of metallic titanium - Google Patents

Electrolytic production of metallic titanium Download PDF

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Publication number
US2848397A
US2848397A US441324A US44132454A US2848397A US 2848397 A US2848397 A US 2848397A US 441324 A US441324 A US 441324A US 44132454 A US44132454 A US 44132454A US 2848397 A US2848397 A US 2848397A
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US
United States
Prior art keywords
cathode
bath
titanium
anode
molten
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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.)
Expired - Lifetime
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US441324A
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English (en)
Inventor
Lawrence J Reimert
Erastus A Fatzinger
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New Jersey Zinc Co
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New Jersey Zinc Co
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Filing date
Publication date
Priority to LU33710D priority Critical patent/LU33710A1/xx
Priority to BE539490D priority patent/BE539490A/fr
Priority to NL198464D priority patent/NL96256C/xx
Application filed by New Jersey Zinc Co filed Critical New Jersey Zinc Co
Priority to US441324A priority patent/US2848397A/en
Priority to GB17056/55A priority patent/GB777892A/en
Priority to FR1133552D priority patent/FR1133552A/fr
Application granted granted Critical
Publication of US2848397A publication Critical patent/US2848397A/en
Anticipated expiration legal-status Critical
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    • 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
    • C25C3/26—Electrolytic production, recovery or refining of metals by electrolysis of melts of titanium, zirconium, hafnium, tantalum or vanadium
    • C25C3/28—Electrolytic production, recovery or refining of metals by electrolysis of melts of titanium, zirconium, hafnium, tantalum or vanadium of titanium

Definitions

  • titanium tetrachloride is a desirable source material for this titanium component of the bath because it can be readily obtained by chlorination of naturally occurring titaniferous materials and can be further purified to the extent requisite for electrolytic production of titanium metal.
  • titanium tetrachloride is not only insoluble as such in the molten salt baths which are generally used for such an electrolytic operation but is also a predominantly covalent non-conductor, and consequently great difliculty has been experienced in using titanium tetrachloride for this purpose.
  • a molten halide salt bath containing a significant amount of titanium dichloride is capable of readily assimilating titanium tetrachloride by converting it to titanium trichloride.
  • the resulting titanium trichloride is not only soluble in the molten halide bath but can be readily decomposed electrolytically with the resulting cathodic deposition of metallic titanium.
  • Such screens do not offer much of a barrier to the circulation of the electrolyte; when used in fused salt electrolysis of titanium halides, they have been used with acceptable efliciency only when electrolysis is carried out at very low solute concentrations. Furthermore, it has been observed that such metallic screens are rapidly corroded in molten salt solutions of titanium chlorides.
  • anode and cathode must be so arranged within the cell that the chlorine evolved at the anode cannot enter to any significant extent the portion of the molten bath adjacent the surface of the cathode facing away from the anode, that is, the distal surface of the cathode.
  • Another condition which we have found essential to obtain the aforementioned result is maintaining direct communication between the body of the bath between the anode and the proximate cathode surface (that is, the cathode surface facing the anode) and the body of the bath adjacent the distal surface of the cathode, while nevertheless minimizing the entry (by circulation or by diffusion, or both) of the titanium chloride component of the latter into the former.
  • Still another condition upon which this result is predicated is the maintenance of an electrolyzing cell voltage which is high enough to effectively deplete the titanium component of the body of molten bath between the anode and the proximate cathode surface but is not so high as to cause decomposition of any of the non-titaniferous components of the bath.
  • our present invention is directed to the electrolytic production of metallic titanium wherein a chloride of titanium having a valence lower than four is electrolyzed between an anode and a cathode in a molten halide salt bath with the resulting deposition of metallic titanium on the cathode and evolution of chlorine gas at the anode.
  • Our improvement in this method which makes possible the production of metallic titanium without the use of any physical barrier in the molten bath between the anode and cathode, comprises (1) establishing and maintaining the relative position between the anode and cathode within the cell such that the evolved chlorine will rise in the body of molten bath between the anode and the proximate cathode surface without entering the body of molten bath adjacent the distal surface of the cathode and sufliciently close to one another to permit electrolytic depletion of the titanium content of the bath therebetween at a rate faster than this titanium content can be replaced by diffusion from other portions of the bath, (2) maintaining the body of molten bath between the anode and the proximate cathode surface in direct communication with the body of molten bath adjacent the distal surface of the cathode through a passage of sufliciently small area to retard diffusion of the tita nium chloride from the bath adjacent the distal surface of the cathode into the bath between the anode and
  • the molten salt baths which are useful in practicing our invention comprise one or more of the halides of the alkali metals and alkaline earth metals.
  • the chlorides, bromides, iodides and fluorides of sodium, potassium and lithium as well as the same halides of calcium, magnesium, barium and strontium may be used with advantage.
  • an individual halide may be used as a single constituent bath, it is preferred to use a combination of these halides inasmuch as such combinations are characterized by relatively lower melting points than the individual salts.
  • the bath should be as completely anhydrous as possible and should be compounded of salts of high purity.
  • a content of titanium dichloride in such a molten salt bath may be established by any one of a number of procedures.
  • titanium dichloride from an extraneous source may be introduced directly into the bath.
  • the titanium dichloride may be formed in situ in the bath by dispersing finely divided metallic titanium throughout the bath and by then bubbling titaniurn tetrachloride into the bath so that, as a result of the reaction between the metallic titanium and the titanium tetrachloride, titanium dichloride is formed in the bath.
  • the lower valence titanium chloride content of the bath may also be established by continuously exposing the bath to a titanium tetrachloride atmosphere while maintaining an impressed cell voltage either below or above the decomposition voltage of one or more components of the carrier salt'bath but sufiicient to effect reduction of the titanium tetrachloride to alower valence titanium chloride.
  • the dichloride can also be formed in the bath by introducing the trichloride into the bath, or forming it in situ by the aforementioned electrolysis, and by thereafter electrolytically reducing the trichloride to the dichloride. Regardless of the source of the titanium dichloride, itspresence in the molten halide salt bath imparts to the bath the'characteristic of readily as- 4 sirnilating titanium tetrachloride when the latter is brought into contact with the bath.
  • the titanium tetrachloride is advantageously supplied to the bath by maintaining an atmosphere of titanium tetrachloride vapors above but in contact with the molten bath.
  • titanium tetrachloride may be introduced into the bath by bubbling it thereinto, we have found that the resulting agitation of the bath is inimicable to the requi ite condition that circulation of the bath components be maintained at a minimum.
  • the cell atmosphere should be compartmented to maintain separation between this atmosphere and the chlorine which is evolved from the anode. Moreover, the cell should be tightly closed to exclude the ambient atmosphere.
  • the relative position between the anode and cathode within the molten salt body, in addition to their being not separated by any physical barrier between significant portions of their effective surfaces, should be such that (a) chlorine evolved at the anode will rise in the body of molten bath between the anode and the proximate cathode surface without entering the body of molten bath adjacent the distal surface of the cathode, (b) these two body portions of the bath are in direct communication with one another through a passage of sufiiciently small area to retard diffusion of titanium chloride from the body portion of the bath adjacent the distal surface of the cathode into the body portion of the bath between the anode and proximate cathode surface, and (c) the distance between the anode and the proximate cathode surface is sutficiently small to permit the electrolytically induced depletion of the titanium content of the molten bath between these surfaces.
  • a number of arrangements of anode and cathode will assure these conditions, and
  • Figs. 2, 3 and 4 are partial sectional elevations of three additional cell arrangements useful in practicing our invention.
  • Fig. 5 is a partial sectional elevation of another modification of anode-cathode assembly useful in practicing our invention.
  • the anode and cathode assembly is positioned within a cell 10 containing a molten salt bath the level of which is indicated by the line 11.
  • the anode and cathode arrangement immersed in this bath in the modification shown in Fig. 1 comprises a central anode rod 12 and a surrounding cylindrical cathode 13.
  • the uppermost end of the cathode is joined to a cylindrical noncorrosive material 14 such as a glass tube, although it must be understood that even a metal tube may be used for this purpose provided that it is not readily attacked by either titanium tetrachloride vapors or chlorine gas at elevated temperatures.
  • the cathode 12 does not extend as far down into the bath as the cathode 13 so that chlorine evolved at the anode during electrolysis will rise upwardly into the atmosphere above the bath where it will be contained within the cylindrical walls 14 whence it can he withdrawn from the cell.
  • the lower projection of the cylindrical cathode 13 further aids in preventing the entry of evolved chlorine from the portion of the bath identified by the letter A (and comprising the bath between the anode and the proximate cathode surface) into the outer portion of the bath identified by the letter B (and comprising the portion of the bath in contact with the distal surface of the cathode 13).
  • the lower extremity of the cathode 13 is provided with an inwardly projecting flange portion 16.
  • This flange portion 16 not only insures containment of the evolved chlorine between the anode 12 and the proximate surface of the cathode 13 but it further restricts the area of the passage through which titanium chloride in the bath portion B can diffuse into the bath portion A.
  • the anode comprises a cylinder 17 positioned either close to or immediately adjacent the side walls of the cell 10, and the cathode comprises a cylinder 13 concentrically arranged within and spaced a short distance inwardly from the anode cylinder 17.
  • Such a partial closure may be provided either by a centrally located disk 18, supported for example by arms 19 dependingfrom the lower end of the cathode 13, or by the same type of inwardly projecting flanges 16 shown in Fig. 2. Either ofthese arrangements effects the desired control over the rate of diffusion of titanium chloride from the body portion B to the body portion A of the bath while nevertheless maintaining direct communication between these two body portions.
  • the anode-cathode arrangement shown in Fig. 4 comprises substantially flat anode and cathode plates or sheets positioned vertically within the cell 10. Both the anode sheets 20 and the cathode sheets 21 extend nearly the full distance across the cell, and are insulated from the side walls of the cell if they are arranged to make contact with these walls, but both the anode and the cathode sheets terminate above the bottom of the cell with the lower ends of the anode being higher than the lower ends of the cathode.
  • each anode 20 is provided with a cooperating pair of cathodes 21 so that with respect to each anode 20 there will be a body portion A of the molten bath positioned between the anode and the proximate surfaces of the cooperating cathodes as well as a body portion B of the molten bath adjacent the distal surface of each cathode 21.
  • the chlorine evolved at the anode leaves the surface of the bath within the confines of the upper cathode walls 14 which thus define a compartment C in the cell atmosphere containing the cell exhaust gas.
  • the portion of the cell atmosphere exterior of this cell exhaust compartment defined by the walls 14 comprises a compartment D into which titanium tetrachloride may be introduced for assimilation by the bath.
  • the titanium tetrachloride is absorbed by surface contact with the body portion B of the bath, that is, by contact with the surface of that portion of the bath in contact with or adjacent the distal surface of each cathode.
  • the body portion A of the bath is maintained substantially completely depleted of titanium ions by control of the electrolyzing conditions.
  • the electrolyzing condition which assures the maintenance of titanium-depletion in the body portion A of the molten bath between the anode andthe proximate cathode surface comprises the use of a voltage sufficiently high to strip the body portion A of the bath of its titanium chloride content.
  • the maximum back electromotive force will be influenced by the bath composition, by the electrode compositions and by the bath temperature, but in general it can be stated that under most conditions our presently preferred upper limit for the back electromotive force is about 3.4 volts.
  • the cross-sectional area of this communication passage between the two body portions A and B may vary considerably provided that it is not so great as to permit a rate of diffusion of titanium chloride from the body portion B into the body portion A at a rate greater than the rate at which titanium chloride can be electrolytically depleted from the body portion A.
  • a multitude of small openings can be used for the direct communication passage between the body portions A and B. For example, we have obtained wholly satisfactory results by operating under the aforementioned requisite conditions with a cathode composed of a metal screen in the form of a cup 22 so that the bottom of the cup, except for the screen openings, completely closed the bottom of the lowermost extention of the cylindrical cathode wall 13.
  • the titanium deposit formed on the distal surface of the screen cathode is sufficiently porous to permit progressive build-up of metal on this distal surface.
  • the resulting mass of deposited metal between the deposition surface thereof and the screen is not, of course, a physical barrier between the anode and cathode as this term is used herein and in the claims.
  • the cell electrodes should, of course, be constructed of material which will not introduce extraneous elements into the fused bath.
  • a nonmetallic anode such as graphite or carbon should be used, graphite having been found in practice to be wholly suitable for this purpose.
  • Cathodes of titanium and nickel, and preferably corrosion-resistant nickel base alloys, are useful in practicing the invention. At the prevailing cell temperature, the aforementioned cathode materials have been found not to contaminate the deposited metallic titanium to any significant degree and may be used in solid or foraminous form.
  • a Pyrex glass cell having an internal diameter of 2% inches was filled with the aforementioned lithium chloride-potassium chloride-sodium chloride eutectic melt to a depth of about 3 inches and maintained at a temperature of 560 C.
  • the electrode arrangement was that of Fig. 2 with a graphite anode inch in diameter and with a nickel-base alloy cathode having an inside diameter of 1% inches and 1% inches long, the bottom of .7 the cathode being provided with a central aperture /3 inch in diameter.
  • a lower titanium chloride concentration of 4.4% calculated as titanium trichloride was established by reacting titanium metal with titanium tetrachloride, and during most of the electrolysis this lower chloride concentration was maintained by adding titanium tetrachloride through the cell atmosphere in balance with the current passed through the cell. Electrolysis was carried out at an impressed voltage ranging from 3.8 to 4.3 volts and with a current ranging from 4.4 to 5.9 amperes. During this interval the back electromotive force, as determined by a high resistance voltmeter, ranged from 2.7 to 3.1 volts. After 5 hours and 20 minutes of operation under these conditions, the titanium tetrachloride feed was stopped and the melt was stripped of lower.
  • titanium chlorides by continued electrolysis at gradually decreasing impressed volt-- age and current.
  • the anode efficiency for the entire run based on evolved chlorine absorbed in a potassium iodide solution, was 84.8%.
  • Essentially all of the titanium metal was deposited on the distal surface of the cathode.
  • titanium lower chlorides generally a mixture of titanium dichloride and trichloride
  • This high titanium lower chloride content results in a high rate of adsorption by the bath of the titanium tetrachloride in the cell atmosphere thereabove and thus leads to the formation of a coarsely crystalline titanium metal deposit on the cathode.
  • the electrolysis may be carried out over an extensive period of operation without danger of the cathode deposit interfering with the cell conditions established by the close spacing of the anode and cathode.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Metals (AREA)
US441324A 1954-07-06 1954-07-06 Electrolytic production of metallic titanium Expired - Lifetime US2848397A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
LU33710D LU33710A1 (fr) 1954-07-06
BE539490D BE539490A (fr) 1954-07-06
NL198464D NL96256C (fr) 1954-07-06
US441324A US2848397A (en) 1954-07-06 1954-07-06 Electrolytic production of metallic titanium
GB17056/55A GB777892A (en) 1954-07-06 1955-06-14 Improvements in the electrolytic production of metallic titanium
FR1133552D FR1133552A (fr) 1954-07-06 1955-06-29 Procédé de préparation du titane métallique

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US441324A US2848397A (en) 1954-07-06 1954-07-06 Electrolytic production of metallic titanium

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US2848397A true US2848397A (en) 1958-08-19

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US441324A Expired - Lifetime US2848397A (en) 1954-07-06 1954-07-06 Electrolytic production of metallic titanium

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US (1) US2848397A (fr)
BE (1) BE539490A (fr)
FR (1) FR1133552A (fr)
GB (1) GB777892A (fr)
LU (1) LU33710A1 (fr)
NL (1) NL96256C (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2892764A (en) * 1958-04-21 1959-06-30 New Jersey Zinc Co Production of titanium metals
US2898276A (en) * 1958-07-01 1959-08-04 New Jersey Zinc Co Production of titanium
US2900318A (en) * 1955-11-29 1959-08-18 New Jersey Zinc Co Electrolyzing device
US2908619A (en) * 1958-08-01 1959-10-13 New Jersey Zinc Co Production of titanium
US2975111A (en) * 1958-03-19 1961-03-14 New Jersey Zinc Co Production of titanium
US2998373A (en) * 1960-02-19 1961-08-29 New Jersey Zinc Co Electrolytic cell for production of titanium
US3054735A (en) * 1960-03-29 1962-09-18 New Jersey Zinc Co Production of titanium
US3274083A (en) * 1963-05-13 1966-09-20 Titanium Metals Corp Electrolytic production of titanium
US4113584A (en) * 1974-10-24 1978-09-12 The Dow Chemical Company Method to produce multivalent metals from fused bath and metal electrowinning feed cathode apparatus
US4165262A (en) * 1976-09-13 1979-08-21 The Dow Chemical Company Method of electrowinning titanium
US4219401A (en) * 1978-08-07 1980-08-26 The D-H Titanium Company Metal electrowinning feed cathode
US4521281A (en) * 1983-10-03 1985-06-04 Olin Corporation Process and apparatus for continuously producing multivalent metals

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1121817B (de) * 1958-12-12 1962-01-11 New Jersey Zinc Co Verfahren zur Herstellung von Titan durch Schmelzflusselektrolyse

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB682919A (en) * 1950-03-20 1952-11-19 Titan Co Inc A new or improved process for the production of metallic titanium

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB682919A (en) * 1950-03-20 1952-11-19 Titan Co Inc A new or improved process for the production of metallic titanium

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2900318A (en) * 1955-11-29 1959-08-18 New Jersey Zinc Co Electrolyzing device
US2975111A (en) * 1958-03-19 1961-03-14 New Jersey Zinc Co Production of titanium
US2892764A (en) * 1958-04-21 1959-06-30 New Jersey Zinc Co Production of titanium metals
US2898276A (en) * 1958-07-01 1959-08-04 New Jersey Zinc Co Production of titanium
US2908619A (en) * 1958-08-01 1959-10-13 New Jersey Zinc Co Production of titanium
US2998373A (en) * 1960-02-19 1961-08-29 New Jersey Zinc Co Electrolytic cell for production of titanium
US3054735A (en) * 1960-03-29 1962-09-18 New Jersey Zinc Co Production of titanium
US3274083A (en) * 1963-05-13 1966-09-20 Titanium Metals Corp Electrolytic production of titanium
US4113584A (en) * 1974-10-24 1978-09-12 The Dow Chemical Company Method to produce multivalent metals from fused bath and metal electrowinning feed cathode apparatus
US4165262A (en) * 1976-09-13 1979-08-21 The Dow Chemical Company Method of electrowinning titanium
US4219401A (en) * 1978-08-07 1980-08-26 The D-H Titanium Company Metal electrowinning feed cathode
US4521281A (en) * 1983-10-03 1985-06-04 Olin Corporation Process and apparatus for continuously producing multivalent metals

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Publication number Publication date
FR1133552A (fr) 1957-03-28
NL96256C (fr)
GB777892A (en) 1957-06-26
LU33710A1 (fr)
BE539490A (fr)

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