US2882144A

US2882144A - Method of producing titanium

Info

Publication number: US2882144A
Application number: US529663A
Authority: US
Inventors: Alan G Follows; Paul A Keene
Original assignee: Allied Chemical Corp
Current assignee: Allied Corp
Priority date: 1955-08-22
Filing date: 1955-08-22
Publication date: 1959-04-14
Anticipated expiration: 1976-04-14

Description

April 14,1959 A. G. FOLLQYWS ETAL METHOD 0;? PRODUCING TITANIUM Filed Aug. 22, 1955.

2 Sheets-Sheet 1 r l a9 ha ha t9 a? a;

.5551 v V. J 2 mm N mm ww @0565 .5903; aosfiw. mw. 236cm 2%. -89; 2 35mi 3a. 216:. mm no 356m 7 .5 H350 INVENTORS ALAN G. FOLLOWS PAUL A. KEENE ATTORNEY INVENTORS 2 Sheets-Sheet 2 April 14, 1959 A. G. FOLLOWS ETAL METHOD OF PRODUCING TITANIUM Filed Aug. 22, 1955 $02453 .Em I

I ALAN G.FOL| OWS PAUL A. KEENE BY w ATTORNEY United States Patent METHOD OF PRODUCING TITANIUM Alan G. Follows and Paul A. Keene, Syracuse, N.Y.,

assignors to Allied Chemical Corporation, a corporation of New York Application August 22, 1955, Serial No. 529,663

13 Claims. c1.1s-s4.s

- This invention is directed to manufacture of metallic titanium.

It has been proposed to make metallic titanium by reducing titanium tetrachloride with an alkali metal e.g. elemental sodium. Known processes involve reaction at relatively low temperature of TiCl, with elemental alkali metal more or less dispersed on inert finely divided carrier material which may be alkali metal chloride or a portion of the reaction product of a previous cycle of operation. In the case of the use of elemental sodium, reaction products are sodium chloride, and metallic titanium which at this state exists in a finely divided, unstable more or less pyrophoric form. Subsequent to the reduction reaction, by procedures illustrated for example by Glasser et al. US. Patent 2,618,549 of November 18, 1952, the resulting reaction mass may be heated or furnaced at temperatures above about 800 C. primarily to convert the metallic titanium to a stable, ductile form which may be exposed to the air. Since this heating step is carried out at temperatures above the melting point of sodium chloride, the latter melts, and-if desired at least some separation of sodium chloride and metallic titanium may be obtained for example by draining some of the molten sodium chloride away from the reaction mass while the latter is undergoing heating. In this situation, at the end of the heating operation, the furnaced material comprises a mixture of stabilized, ductile finely divided metallic titanium and some occluded sodium chloride. Following suitable cooling, the furnaced material, consisting of a solid, brittle mass more or less sponge-like in physical structure, may be ground and leached with water or weak hydrochloric acid to dissolve out the solidified residual sodium chloride. After leaching and drying of the resulting finely divided metallic titanium, the latter may be arc-melted and cast in ingot form. As known in the art, metallic titanium prior to stabilization is highly reactive with even very small amounts of elements such as oxygen and nitrogen, and therefore the entire operation up to completion of furnacing should be carried out in an inert atmosphere such as that formed by a blanket of relatively low positive pressure inert gas such as argon, krypton, or helium.

Heretofore, the advantages potentially possible by use of metallic alkali metal as reducing agent have not been fulfilled. A major object of the present improvement lies in provision of processes affording procedures which facilitate placing the TiCl -elemental alkali metal method for making metallic titanium on a continuous basis. Other objects include provision of processes which minimize formation of any substantial quantities of subquality titanium metal, and eliminate mechanical operational deficiencies, characterized by caking and balling up of solids, and plugging of the process dispersers, reactors, heat exchangers and connecting transfer lines, to such an extentthat satisfactory continuous operation becomes possible. Theinvention is directed more particularly to provision of procedures for efiecting manufacture, on a continuous basis, of reaction products consisting of 2,882,144 Patented Apr. 14, 1959 ice a mixture of alkali metal chloride and metallic titanium in the unstable form.

In accordance with one major feature of the invention,

Figure 1 is a view, partly in longitudinal section and.

partly in diagrammatic elevation of apparatus which may be employed in accordance with the principles of the invention to effect formation of the metallic titaniumsodium chloride reaction product;

Fig. 2 is a diagrammatic end elevation of the apparatus of Fig. 1;

Fig. 3 is a longitudinal vertical section of one type of furnacing retort;

Fig. 4 is a longitudinal vertical section, partly diagrammatic, of a modified form of furnacing retort; and

Fig. 5 is a diagrammatic elevation of a modified form of the apparatus ofFig. 1.

Referring to Fig; 1, reference numeral 10 indicates generally a, disperser-reactor comprising a horizontally elongated flat-topped, vertically-sided shell having a double U-shaped bottom 11 (Fig. 2), and supported in the position indicated by means not shown, and closed at either end by vertical end walls 12. Conveyor-agitator shafts 13, connected at one end to motor 14, are rotatably mounted by suitable gas-tight bearings in end walls 12. Attached to the under side of the shell top is a baffle 15 which is approximately rectangular in elevation as indicated by the dotted line 16 of Fig. 2. As shown in Fig. 1, the upper edge of bafile 15 is welded or otherwise connected in gas-tight relation to the contiguous portion of the shell top. The bafile extends downwardly to approximately the circumferences of shafts 13, and in effect partitions the shell to form in one end thereof a dispersing zone 21 and in the opposite end a reaction zone 22. In the embodiment illustrated, each shaft carries a multiplicity of groups 23 of radially disposed conveyor-agitator paddles 24. Each group includes 4 paddles, and is axially spaced apart for adjacent groups on the same shaft, and is mounted in staggered relation with respect to adjacent groups on the other shaft. Paddles of a group are mounted in degree relation to each other. Each paddle is adjustably attached to its shaft, and the paddles are formed and pitched so as to move solid material through the shell in the direction of the arrow 26, and to effect, in conjunction with rate of rotation of the shafts,

intense agitation of solids in the shell. Shafts 13 may be connected to rotate in the same or opposite directions.

The shell is provided at the dispersing zone end with an inlet 29 for recycled solids and with an inlet 30 for liquid alkali metal such as elemental sodium. TiCL, in vapor form may be introduced into the inlet end of the reaction zone 22 thru a feed pipe 31 placed close to the reaction zone side of battle 15. At the discharge end, shell 11 is equipped with a hopper-like outlet 33 which feeds reaction product thru a valved connection 34 into a reactor product chamber 36.

Numerals

38 and 39 respectively denote sources of liquid metallic sodium, and TiCl in vapor form, which materials are conducted to

shell inlets

30 and 31 thru suitable valve controlled

pipe connections

41 and 42. As diagrammatically shown, particularly in Fig. 2, the interior of the reactor product chamber 36 is associated 3, with an elevating conveyeiindicated generally by 44, which transfers reactor product to the inlet 45 of a heat exchanger 47. Structurally, exchanger 47 comprises an elongated cylindrical shell 49 having at the outlet end a discharge hopper 51-, and having rotatahly mounted in gastight relation in the end walls a shaft 54- connected to motor 55 and carrying screw conveyor flight 57 rotated and pitched to move solid material in the direction of the arrow 58. Shell 49 is jacketed as at 59 to provide for circulation of heat" transfer medium ordinarily needed for cooling of solid material being passed thru shell 49. The discharge hopper 51 of the heat exchanger is connected thru a valve controlled outlet conduit 62 with a product receiver 64 which in turn communicates thru a valve controlled transfer pipe 66 with a retort charging chamber 67. A chute 68 afiords means for feeding recycled solids to dispersing zone inlet 29.

All of the equipment thus far described may be made of any suitable non-corrosive and non-product contaminating material such as mild steel. Further, as previously indicated, the processes which may be carried out in such equipment are effected preferably under a relatively low positive pressure (e.g. 2 to 10 inches of water) of an inert gas such as argon, helium and krypton. Hence, all of the apparatus described is equipped with various inert gas supply tanks under pressure of such gas, pipe connections, gauges, etc., not shown, arranged to maintain all of the materials being processed, from the control valves in sodium and

TiCl inlet pipes

41 and 42 thru and including the interior of retort charging chamber 67, under the desired positive pressure of inert gas.

Fig. 3 illustrates one type of retort in which the metallic titanium-sodium chloride reactor product may be furnaced. This retort, which may be of stainless steel throughout, comprises a cylinder '70 one end of which is closed gas-tight by disk 71. Welded to the lower end of cylinder 70 is a flange 73 drilled to accommodate bolts 74. The bottom end of the retort comprises a similar cylinder 76 the bottom of which is closed by a disk 77, and to the upper end of which iswelded a flange '78. Clearance and formation of contiguous faces of flanges 73 and 78 are suflicient to permit, in the assembled form, clamping of screen 80 between adjacent cylinder ends and the placing of an annular sealing gasket 81 between adjacent flange faces. Cylinder '70 above screen 80 provides a reactor product charge compartment'83, and cylinder 76 below screen 80 affords a sodium chloride drain age and receiving compartment 84. The furnace in which the retort of Fig. 3 may be 'placedis notshown.

Fig. 4 shows a modified type of furnacing retort 86 comprising an elongated cylinder 87, gas-tight closed at the bottom by a disk 88 and providedwith an integrally formedflange 89 'at the top. Adapted to rest on the bottom of cylinder -87 is a second cylinde'r made in sections 92am 93 in such 'a way that screen 95 may be securely clamped between such sections. Section '92atfordsa reactor product charge chamber 97, and section 93provides a receiver for moltensodiurn chloride. The top of cylinder 87 may be closed by a disk 99 provided with a valved connection 101 for inertfgas. Theretort and accessories may be made of stainlesssteel. Numeral 105 designates a furnaceshown diagrammaticallyinto which retort 87 may be placed. I

In the modified form of 'apparatus'of Fig. 5,'structurally the disperser 107 may "duplicatesubstantially the reactordis'perser of Fig. 1 minus'th'e partition 15 and the TiCL; inlet 31 of Fig. 1. Thereacto'r 108 of Fig. '5 may be constructed substantially the 'same as the 'disperser1tl7 or Fig. except that conduit 110 provides for transfer of the dispersion of sodium on recycled solids from disperser 107 to reactor 108 which isjequipp'ed with'an inlet 111 for introduction of vaporous TiCl Reactor product'lcollect'or 1-13, conveye'r system-lldfand heat exchanger 115 of Fig. 5 may be substantially the same as correspond ing apparatus units of Figs. I 1 and 2.

Assuming use of elemental sodium as TiCl, reducing agent, the invention process involves lowtemperature reduction of titanium tetrachloride by means of elemental sodium dispensed throughout a great many times greater weight bulk of finely divided substantially freeflowing solid carrier material preferably consisting of a portion of the metallic titanium sodium chloride reaction product of a previous reaction cycle. More particularly, but apart from certain hereinafter described operation factors, principal procedural features of the present improvements include continuously dispersing elemental sodium in liquid form on the carrier material in a. dispersing zone in the substantial absence of titanium tetrachloride, preferably continuously transferring the thus dispersed elemental sodium and, carrier material from the dispersing zone into a reaction zone while continuously feeding titanium tetrachloride in vapor form into the reaction zone to effect formation of a reaction mass comprising metallic titanium, sodium chloride and preferably a small amount of sodium, and continuously discharging such reaction mass from the reaction zone, it being understood that the entire foregoing operation is carried out in an inert atmosphere which, from a practical viewpoint, may be formed by a blanket of argon or other similar inert gas maintained under relatively low positive pressure.

Referring particularly to Fig. 1 of the drawing, practice of the invention includes provision of a source of feasibly pure titanium tetrachloride in vapor form, preferably held at temperature in the range of above the 136 C. vaporization point of TiCl to 250 C. or higher, and at pressure high enough to facilitate charging vaporous TiCL, into the reaction chamber 22 against the back pressure of the argon gas blanket maintained therein. Operation also involves maintenance of a source of purified liquid rnetallic sodium. Storage tank 38 maybe arranged to supply liquid sodium to dispersion zone inlet 30 at temperature in the range of say 110225 C. Purified metallic sodium may be obtained by melting commercial metallic sodium, and filtering the molten material for example successively through 20 micron and 5 micron stainless steel filters.

In accordance with the invention, it has been found that the following additional principal procedural factors and control conditions interdependently contribute to'the herein exemplified results: composition of the recycle, or sodium carrier, as introduced into the dispersion zone; physical nature and composition of the sodium-on-carrier dispersion, and the manner of making the same in the dispersion zone; reaction zone conditions including the carrying out of'the Na-TiCL, reaction in the presence of a certain excess of sodium; relative and total amounts of Na and TiCl fed into the process; weight ratio of recycled carrier to total weight of Na and TiCl, fed into the process; and formation of a reaction zone exit (which includes the make of a cycle) containing a certain amount of sodium.

The carrier of sodium or recycle used may be any relatively pure sodium chloride, or metallic titanium permissibly theunstabilized type, or any mixture of these materials. From practical standpoint, the carrier is finely divided substantially free fiowing'solid material which is the metallic titanium-sodium chloride reaction product resulting froma previous reaction cycle. 'This material, usually sufiiciently finely divided so that passes a IOmeshscreen,mayscontain 'about 15-17% by weight of metallic titanium, although "as shown by the herein appended "examples, metallic titanium coutentis usually and preferably in the-range "of 16-17%. "In the usual course of operations, such material contains small amounts of titanium-subchlorides and corresponding small'amounts of hereinafter more fully defined unused reactant sodium. In accordance-w ith one aspect of the-invention, the recycle, asife,d into-the disperser,-;s l 1ould contain some hereinafter 1 more *fully defined stoichiom'etric excess sodium, at 'least 0.l by weight, "preferably 0.2-1 :5 ,"and

most desirably 02-10%, the purpose "of which stoichiometric excess sodium content will hereinafter appear. Aside from the foregoing substances, the balance of the recycle material is NaCl.

A major feature constituting basis for successful continuous cyclic operation of the present process is formation of a thorough dispersion of metallic sodium on the carrier material. Because of high chemical activity of sodium, in order to satisfactorily control the course of reaction of TiCl and sodium, it is necessary to distribute only a relatively small amount of metallic sodium throughout a relatively large body of carrier material which serves not only as a carrier for the reactant sodium reactable to produce cyclic make and other sodium not reactable to produce make, but also functions as a reaction intensity and temperature control medium which smooths out temperature conditions in the reactor by taking up and distributing large quantities of heat. Reactant sodium is used herein to define the increment of metallic sodium which is fed into the process in amount-substantially stoichiometrically equivalent to the total amount of introduced TiCl In accordance with the invention, a finish'ed dispersion as discharged from the dispersion zone contains not more than about 3.5%, preferably not more than 3.0%, by weight of total metallic sodium. Minimum total Na is not critical but is preferably 0.7% by weight. Further, it has been found that in order to put the TiClr-Na reaction on a successful continuous basis, the dispersion of sodium throughout the carrier should be effected in the substantial absence of TiCl Developmentwork shows that if formation of the dispersion is carried out in the absence of any significant amount of titanium tetrachloride, it is possible to bring about an even dispersion of sodiumgthroughout the carrier, and more importantly, to effect formation'of the dispersion in a dry and free-flowing physical condition which prevents balling and plugging-up in the dispersion zone and in subsequent apparatus units.

In view of ultimate teaching herein, starting-up procedure will be within the skill of the art, and hence for purpose of further delineation of details of the invention, it may be assumed that the process is under way, and that in addition to availability of vapor form TiCl and liquid metallic sodium, there is also being discharged from the heat exchanger 47 a reactor exit of a previous cycle, part of which exit is process make and, by adjustment of the valve in exchanger outlet conduit 62, is transferred to product collector 64. The balance, constituting recycle of the above described composition, is passed thr-u chute 68 to the carrier material inlet 29 of the dispersing zone.

Operation effected in dispersion zone 21 is carried out at temperatures well above the 97.6 C. melting point of elemental'sodium to insure absence of any solid sodium during formation of the dispersion. Ordinarily, overall temperatures in the dispersion zone should be held at not less than about 125 C., and in usual operation may lie in the range of about 140-200" C. Taking into account the size, capacity and normal radiation heat losses of a particular piece of apparatus, temperature control in the dispersion zone may be effected by regulating temperatures of incoming liquid sodium or carrier material or both. Primary purpose of heat exchanger 47 is to afford supply of carrier material to dispersion zone inlet 29 at temperature at least above the melting point of sodium. Usually, the heat exchanger functions as a cooler, but may under some circumstances be operated as a heater to bring up recycled reaction product to the required temperature prior to introduction into the zone 21. Liquid sodium may be fed into the dispersion zone at temperature in the range of about 110-225 C., and recycled reaction product fed thereto at temperature in the range of about 140200 C. It will be understood that for any given operation, temperature of incoming liquid sodium and recycle reaction product may be adjusted with re- 6 spect to each other so asto maintain an effective minimum temperature in the dispersing zone.

Sodium fed into the dispersion zone thru supply pipe 41 should be such as to provide the preferred 0.7-3.0% total sodium to recycle weight values noted above.

Residence time and agitation in the dispersion zone are of importance. Residence time is a factor related mostly to particular apparatus. While in say a ten ton metallic titanium'per day plant, residence time may vary from 2 to 8 minutes, because of permissible variability of overall operating conditions and of apparatus design, it is not possible to specify residence time suitable for all operations. As previously noted, conveyeragitator design and permissible speed of rotation are such as to forward solids at the desired lineal rate while at the same time creating violent and intense agitating conditions. Preferably, the total volume of material in the dispersion zone and factors of agitator paddle design and rate of rotation are such that all during operation there is maintained in the dispersion zone a highly disseminated body of material occupying the lower two thirds or more of the dispersion zone. In the case of the particular apparatus of Fig. 1, the foregoing agitation conditions in conjunction with bafile 15 and the solids being discharged from the dispersion zone under the edge of the baflle and into the reaction zone form an effective vapor seal between the reaction zone and the dispersion zone in order to prevent the presence in the latter of any appreciable amount of TiCl Hence, with the foregoing features in mind, for any particular design of apparatus, rate of conveyor-agitator rotation and optimum residence time in the dispersion zone may be determined by test runs.

Reduction of TiCl elfected' in reaction zone 22 is exothermic. Reaction temperature therein may lie in the range of -350 C., but is more customarily and preferably in the range of about -300 C. Reaction zone temperatures below about 150 C. while useful are not conducive to best results. On the other hand, it is found that temperatures above about 350 C. are not required, this feature of the invention affording the advantage of use of conventionally constructed apparatus made of relatively inexpensive mild steel. Taking into account normal radiation heat losses from a given reaction zone, temperature control therein may be had by regulation of variables such as the amount of reactants present, temperature of dispersion fed into the reaction zone, and temperature of the TiCl vapor charged thereto. Regulation of reaction zone temperature may be had primarily by adjustment of the temperature and to some extent quantity, of the recycled solids fed to the disperser. Such temperature may be selected with regard to other more or less fixed operating conditions so as to maintain temperature in the reaction zone at the desired levels.

In accordance with another feature of the invention, it has been found that TiCl should be supplied to the reaction zone 22 in vapor form. This procedure appears to promote almost instantaneous reaction and minimization of subchloride formation. More importantly, vapor form supply of TiCL, avoids the presence of any liquid in the reaction zone, and experience indicates that this feature, in conjunction with the above described formation of the sodium dispersion on recycled solids, is a major contributing factor with regard to avoidance of apparatus plugging and placing the process on a successful continuous operation basis. TiCl may be fed into the reaction zone at temperatures from slightly above the vaporization point up to 250 C. or higher if desired.

As shown by appended examples, the herein process is such that reduction of TiCl to metallic titanium approaches theoretical. Nevertheless, from time to time the material exiting the Na-TiCl reaction zone may contain variable relativelyvery small quantities of ti! 7 tanium sl'ubchlorides. in "these instances, the reaction zone exit also contains "nausea reactant sodium "which expression defines an increment of sodium which (a) 'Was initially Tied into the lproecs's as part of the reactant sodium and Was unused because of incomplete reduction or illicit to Ti, and (b1) exists in the reaction zone exit in amount corresponding with the titanium subehloiiides content thereof, ie. an amount which would have been used had all the 'subchlorides been fully reduced to it has been found that in order *to insure the absence of titanium subchlerides in "the final metallic titanium of the process, "the material gathered in the reactor roduct collector 64 for preferred operation ehould contain a small amount of stoichiometric excess sodium which ex ression define's an inerernentof sodium over and above the quantity of sodium needed stoichiometrically to reduce all IiCl; to Ti. Thus, with res ect to material gathered in collector 64, istoichiometr ie exsodium "designates sodium "over and above any onused reactant sodium" which may be present. a "furnaeing o eration, subsequently to be oeseribe'd, sioi'chiornetrie xcess sonium functions under the relatively rigorous furnacin' conditions to drive to complereaction of any titanium subchloride's and unused "re'a'ct'ant sodium and thus clean up reduction of any subchlorides which ossibly may be present. If not needed in the -furnacing :ste to insure elimination of titanium subclilorides, the presence of stoichiometric excess sodium afi'oriis no disadvantages because of 'its ready separation -fro'm furnaced Product by a leaching to be described. 'Thus, a feature 'of the invention comprises production of a fich -Na reaction zone "exit containing the amount of stoichiorneltric 'eiice's's sodium desired to be present in the cyclic make which firnay be continuously :s'epara'tetl out or the circuit and fed into bin 64. :s'toichionretrie excess sodium content of the reaction zone can "sho'uldibe at least 0. 1% by weight, may be high as about 1.5%, and preferably is in the range of about 024.

Another teat-tirevindicated by ex erience to be notabl conducive to hi h reduction of Ticl obtained in the reaction zone is "n'raintenance therein of the presence or a substantial reaction z'onc excess of sodium over that theoretically required to completely reduce the TiCl, ipre'sent. While any substantial reaction zone sodium excess is conducive to improvement of results, it has been found that the reaction zone operation should be such {that there is constantly maintained therein preferably "at least about 15% by weight excess sodium over that theoretically needed to reduce all TiCl resent to Ti. In most operations, such excess is well above the 15% indicated, but need not be :above about 200%. In some practice, more desirable results are obtained when the "excess is not less than 'about 20%. It is :notedt'hat the "foregoing values do not include whatever relatively small uantities of unused reactantsodium which might posi's'ibly be present, iie. brought into the reaction zone as a recycle constituent.

With regard to rel'ative amounts of TiCL; and "elemental sodium fed into the process circuit through supply pipes 42 and 11, sodium is charged toprovide a reactant'so'cliu'm feed of at least and preferably just about a stoichiometric quantity of reactant Na on the basis of fed 1301 iie at -'all times, rio] and at least an a roximately stoi hiometric quantit bf reactant Na are bontiililu'ously fed :into the cyclic bifEllit. HGWeVe't, it will be fldfetl that the malce of each cycle is bl'ed out of' the circuit, and that the bled out make takes out of the circuit the s'toichiorrietric excess sodium content *of such iri'ake. The 'thus lost stoichiorrretric :ence'ss sodium is referred to therein :as bleed iloss sodium? sH'enc'e, continuously or intermittently there is aiii ttoouccit into the circuit, thrn f'stidium supply conduit '41, an additional amount or soiiiuni, over stoienitsinetrie Na requirements, approxi- Du'ring mateiy corresponding to the bleed loss sodium. inggly, it will be noted that all during o eration, yaporous TiCh is ied into the reaction zone in {quantit which is less than that theoretically needed to react with all lle mental sodium present, and also that, because of feed into the reaction zone of stoichiometric amounts of :Na :plus additional Na -equivalent to bleed loss sodium, the "above discussed reaction zone Na excess to-be mainiained present in the reaction zone always may be held constant at a chosen level, i.e. preferably not below the indicated by weight.

The total weight'of TiCl and "of reactant Na (which does not include the small amount of bleed losssodium preferably used to 'olfset Na loss in the make) '-fed into the circuit may be varied depending upon the quantity of carrier material recycled. A further feature of the invention comprises regulating the amount of recycle charged into 'the dispersion zone so as to provide in the reaction zone a preferred weight ratio of recycle to total weight of (a) fed TiCl; :plus (1)) an approximately stoichiom'etric equivalent of fed reactant Na, preferably approximately in "the range of 60:1 to 1. Previous discussion shows that *for best operation im ortant neocess factors are :1) a dispersion zone exit containing not more than 3.5% by weight of total Na, preferably not more than 3%; ('2) maintenance :in the reaction zon'e'of the presence of preferably at least :a 15% excess or We over that needed to theoretically react with all thelliGl; present; 3) and for'rnation of a reaction zone exit con taining stoiohiorn'etric 'eirce'ss sodium in amount preferabry in the ra'nge of about 012 1 .0% by weight. In oordanee with the invention, it has been :iound that wh'en Tich and the approximately stoichiornetric quantityot reactant .Naare ted into the 'eircuit thru

conduits

42 and 41, and the recycle employed contains about 01 13097, by Weight of stoiehiometrie excess Na, if the preferred weight ratio :ra-nge of :1 to :1 is utilized, operation is such that the three just previously named pr'oces's factors are automatically rnaintained.

"when, as preferred, the recycle employed contains o. 2-1.;0% bywei h't of -stoichiometric eiicess Na, the 25: 1 weight r'atio' provides disperser zone exits containing about h s-253% by "weight "of Na; ihe'presen'ce in the reaction zone ofa 15-75% by weight reacti'on zone excess of Na over that needed to react theoreticallywith all of the TiCl 'fe'd (which reaction zone excess does not include whatever'amo'unt of Na ma'y he introduced into the *c'ir- "cuit to offset bleed loss sodium); and reaction zone eiiits containing about on-1.0% by weight of stoichionrethie 'ei'ices's Na. On the 'otherhand, the 60:1 weight ratio provides dispersion zone exits containing about 0.7 1535 by Weight of Na; the presence in the reaction zone "of about 36 18096 b weight-excess of Naover that needed to react theoretically with all the Ticl fed; and reaction zone exits containing about 0.2-1.()% by weight "of 'stoichioni'e'tric excess Na. when desired to insure "the presence in the reaction "zone of a greater minimum excess "of sodium, o erations may beconoucted so "that the described "Weight ratio is in the range of "about 605 1 "to 33:1. When using the 3321 ratio and the preferred 0.'2-l;'0'-% by weight 'st'oichiometric excess N'a recycle, disperser'zone "exits may 'contain'about '1.2'2;0% -Na;"t h'e sodium excess in the reaction zone is in the range of about maroon, and reactio vzone exits contain about 032 1 KW, -o"tstoichiotnetrieesrcess Na. Byway or illustration, when e loying apparatus similar to that show in Fi s. '1 and 5 of "the drawing, assuming about 1'0 tons "per day production of metallic titanium, substantiall all heat removal from the "system by "means or h'ea't "exchanger -47, a :dispe'r'sion "zone exit temperature of about 1*2'5 and "use of a recycle containing about '0I2% by weight or stoichiometir excess Na-"when wonking with a ratio iii-3 the dispersion zone exit eontoins by Weight about 1.2% Na, ihe'react'ion :zone sodium-ek to "Cc'ss pre'seiit'ih' t'he reaction zone about "20% byweight,

the reaction zone exit containsabout 0.2% by weight of stoichiometric excess Na, and the reaction zone temperature sustains itself at about 250 C. or something a few degrees less. Herein given values as to Na content of dispersion zone exits do not include the whatever relatively small quantities of unused reactant Na which might possibly be present, i.e. brought into the disperser as a recycle constituent.

Agitation and residence time conditions in the reaction zone are generally comparable with those described in connection with the dispersing zone. Although in the reaction zone thorough agitation is equally important, residence time is not so much so since reaction for the most part appears to be instantaneous. Thus, residence time in the reaction zone approximately the same as that in the dispersion zone, while not necessary, beneficially promotes completion of reaction. Since volume of solids in the reaction zone increases in accordance with the make of any incremental portion of a reaction operation, the reaction zone solids volume runs higher than that of the dispersion zone. Accordingly, if desired, the paddles of the conveyer-agitator in the reaction zone may be more steeply pitched to effect more rapid passage of solids thru the reaction zone, this procedure being possible because residence time in the reaction zone may be appreciably less than optimum residence time in the dispersing zone.

By means of reactor exit product collecting and elevating apparatus indicated in Fig. 2, reactor product recovered in chamber 36, ordinarily at temperature not much below the average temperature level existing in the reaction zone, may be introduced continuously into heat exchanger 47 via inlet 45. Under practically all good operating conditions, the reactor exit as fed into the heat exchanger is at temperature above the temperature desired for recycled solids in chute 68 connected to dispersing zone inlet 29. Rate of flow of cooling medium, such as a suitable oil, thru heat exchanger jacket 59, and rate of movement of reactor product thru the heat exchanger are regulated primarily to facilitate feeding into chute 68, at the proper temperature, that portion of reactor product to. be recycled. The remainder of material discharged from the heat exchanger, corresponding to the process make, is transferred thru pipe 62 into the reactor product collecting bin 64. As previously described, this material is dry, free-flowing and usually contains by weight about 16-17 titanium in the unstable form, small corresponding amounts of titanium subchlorides and unused reactant sodium, balance being NaCl plus preferably 02-10% of stoichiometric excess Na. The foregoing product, still blanketed by positive pressure argon, is then heat-treated at higher temperatures to convert the unstable metallic titanium to the stable, ductile form. Heat treatment may be efiected in a retort such as shown in Fig. 3.

The retort is dismantled (bolts 74 removed) and placed in a retort charging chamber indicated at 67. The chamber, communicating feed pipe and retort are air-evacuated and blanketed with positive pressure argon. The long end 70 of the retort is charged with solids from the reactor product storage bin 64 by transfer thru conduit 66. The reactor is assembled with filter screen 80 and gasket 81 in place, the retort ends are bolted together, and the unit is removed from the argon atmosphere of the charging chamber to the air. The filter element 80 may be 0.04 inch wire cloth made of stainless steel. It will be understood that the solid material in the retort at this stage is still under the positive argon pressure existing in the charging chamber.

With the short end 76 of the retort down, the retort may be lowered into a gas-fired furnace (not shown) in which the material in the tube is heated for a substantial time at temperatures above the 804 C. melting point of sodium chloride and below the temperature at which metallic titanium begins to alloy with iron, i.e.

10 about 975 C. More particularly, heating may be efiected at temperature in the range of about 850 to 950 C. for from 2 to 4 hours. During heating, sodium chloride melts, and the metallic titanium is converted to the stable form. More or less sodium chloride drains thru filter 80 and collects in lower retort chamber 84. In the course of furnacing, solids in the upper end of the retort shrink away from the side walls thereof, and on completion of heating the solid residue in compartment 83 is more or less rod-like in form approximated by the dotted line 82 shown in Fig. 3. r

The tube is removed from the furnace, cooled and opened. The shrunk rod, easily shaken loose from the filter wire 80 and from any incidental points of contact with the lower periphery of the tube 70, is a frangible, more or less sponge-like mass which in a typical operation as presently illustrated may contain by weight about equal parts of metallic titanium and solidified NaCl. This material is crushed to below $4 inch, leached with about a 3% HCl solution, and then with water until chloridefree. The solid residue may be methyl alcohol washed and dried at about 60 C. in vacuum. The dried material is stabilized, ductile metallic titanium, i.e. so-called sponge, all of which passes about a 6 mesh screen. If desired, the product may be arc-melted and cast into ingots.

Furnacing of reactor product in the apparatus of Fig. 4 is approximately the same as in the retort of Fig. 3. Re tort 86 is charged in retort charging chamber 67, and then transferred to furnace 105, after which the interior of retort 86 is kept under argon blanket by connecting an argon source to pipe 101 and opening the valve thereof.- Subsequent operation may be substantially the same as noted in connection with the retort of Fig. 3.

Taking into consideration the 623 C. melting point of K, the 776 'C. melting point of KCl, the 5 C. melting point of the equimolecular NaK alloy, and the approxi" mately 660" C. melting point of the equimolecular =NaC1--KC1 mixture, it is within the skill of the art to use potassium or the NaK alloy in place of sodium in practice of the invention.

The following examples illustrate practice of the in vention.

Example 1.This operation was carried out in appa ratus substantially the same as illustrated in Figs. 1 and 3 of the drawing. Internal axial length of the reactor disperser unit 10 was about 72 inches, internal vertical cross-sectional area about 1.25 sq. ft., and bafiie 15 was located about midway of the unit. The unit was wrapped in a 1.5 inch layer of insulating material to reduce radi ation losses. The interior ofthe entire apparatus thru and including the reactor product storage bin 64 was maintained all during operation at a positive pressure of argon of about 2 inches of water.

The following delineates average conditions over an approximately 3 day continuous run.

Reactor product from previous cycle, analyzing byweight about 0.5% stoichiometric excess Na, and with balance about 16.9% Ti and 82.6% NaCl (basis complete reduction of TiCl to metallic Ti), was continuously fed thru chute 68 into disperser inlet 29 at temperature of a few degrees below C. and at the rate of about 840 lbs./hr. Commercial metallic sodium was melted and purified by filtration successively thru 20 and 5 micron stainless steel filters. Purified liquid sodium (reactant sodium) was introduced into disperser inlet 30 thru conduit 41 at temperature of about C. and at a rate ofabout 5 lbs./hr. The combined quantity of recycled solids and sodium fed provided about 40 lbs. of material in the dispersing zone during operation. Average temperature in the dispersing zone was of the order of 140-l60 C. Pitch of the conveyer paddles and the approximate 200 r.p.m. rotation of the conveyer shafts 13, rotating in the opposite directions (arrows 17,'Fig. 2), maintained conditions of vigorous agitation and: tumbling of material such that the dispersion zone was.

flooded to a. level above the under edge of balfie 15 and provided residence time of incremental portions of the dispersion in the dispersion zone of about 3 minutes. Including the stoichiometric excess sodium contained in the recycled solids as fed into the dispersing zone, the Na content of the dispersion, as continuously discharged in a free-flowing condition into the reaction zone thru the relatively vapor-tight seal formed under the edge of bafile 15, was about 1.1% by weight.

Vaporized TiCl at temperature of above 140 C. was fed continuously into reaction zone inlet 31 thru inlet pipe 42 at rate of about lbs./hr., i.e. substantially the amount of TiCl theoretically needed to react with the reactant sodium fed in thru disperser inlet 30. The total quantity of TiCl introduced was such that, including the stoichiometric excess sodium content of the recycle and the reactant sodium fed into dispersed inlet 30, there was present in thereaction zone about 4.2 lbs/hr. of Na in excess of that theoretically required to react with all the TiCL; charged, that is, the reaction as a whole was continuously carried out in the presence of not less than about an 84% by weight excess of sodium over theory. Exothermic reaction took place, and reaction zone temperature was within the range of about 200 to 230 C. Residence time and conditions of highly vigorous agitation of solids in the reaction zone were about the same as in the dispersion zone. Reactor product, which included make and recycled solids, was continuously discharged into reactor product receiver 36 at rate of about 855 lbs/hr. at temperature of approximately 220 C.

Such product was continuously fed into inlet 45 of heat exchanger 47 at a temperature of about 170 C. Heat transfer medium employed was conventional high temperature heat transfer oil. The particular heat exchanger employed was jacketed and equipped with a screw conveyer provided with means for circulation of cooling medium therethru. Inlet temperature and How of cooling medium thru the jacket and thru the conveyer, and rate of rotation of the conveyer were such that solids were discharged continuously into heat exchanger outlet 51 at temperature of about 145 C. By suitable adjustment of the valve in transfer conduit 62, about 840 lbs/hr. of solids were returned to the dispersing zone, the balance, constituting approximately the make, was run into reactor product collecting bin 64 at the rate of about lbs/hr. This product analyzed by weight 0.5% stoichiometric excess sodium, and with balance about 16.9% Ti and 82.6% NaCl (basis complete re duction of TiCl to metallic Ti). Weight ratio of recycle to the total weight of fed TiCL, and fed reactant Na in this operation was about 56/ 1. During the course of the run, there was added a small but sufiicient additional amount of sodium above overall theoretical requirements to offset the bleed loss sodium corresponding to the amount of stoichiometric excess sodium discharged into product collector bin 64 as a constituent of the make. In this manner, the presence of the above-noted 84% excess of sodium in the reaction zone 22 was maintained throughout the operation. The foregoing run was continuous without interruption, and no balling up of material or plugging of any of the apparatus was encountered.

A 5-6 pound sample of product collected in bin 64 was placed in a retortsimilar to that of Fig. 3 in the argon blanketed manner already described. The retort and the material contained therein were placed in a gasfired furnace and heated therein at temperature in the range of about 850. to 950 C. for a period of about 4 hours. The retort was removed from the furnace. cooled, opened to the. air, and the solid residue was found to be" substantially all. shrunk away from the retort walls and-to be. in the formapproximately as indicated by the dotted line 82 in-Fig; 3. The mass was easily shaken loose from screen 80 and the lower periphery of retort section 70. Color was relatively light grey, and physical structure was cellular and more or less sponge-like. The quantity of sodium chloride which drained into retort bottom section 76 during furnacing was such that the solid residue recovered from retort section 70 contained about 50% by weight of metallic titanium and about 50% by weight of NaCl.

The foregoing material was crushed to pass 6 mesh, leached 3 times with a 3% HCl solution, and then waterwashed about 4 times until filtrate was chloride-free. The water-washed material was then Washed once with methyl alcohol and once with ether, and dried at about 60 C. in vacuum. Notwithstanding some known air leakage into the retort during furnacing, the dried ma terial analyzed by weight not less than 99.5% Ti, and contained not more than 0.25% oxygen, 0.25% nitrogen, and 0.05% carbon. A sample of this sponge product was arc-melted under an argon blanket, and the resulting ingot had a Brinell hardness of 220.

Example 2.-This operation was carried out in apparatus substantially the same as illustrated in Figs. 5 and 4 of the drawing. Internal axial length of each of the disperser 107 and of the reactor 108 was about 72 inches, and internal vertical cross-sectional area of each about 1.25 sq. ft. Both units were wrapped in a 1.5 inch layer of insulating material to reduce radiation losses. The interior of the entire apparatus of Fig. 5 thru and including the reactor product storage bin 120 was maintained all during operation at a positive pressure of argon of about 9 inches of water.

The following delineates average conditions over an approximately two-week continuous run.

Reactor product from previous cycle, analyzing by weight about 1.0% stoichiometric excess Na, with balance about 16.8% Ti and 82.2% NaCl (basis complete reduction of TiCL; to metallic Ti), was continuously fed thru chute 117 into the inlet of disperser 107 at temperature of a few degrees below 170 C. and at the rate of about 1500 lbs/hr. Commercial metallic sodium was melted and purified by filtration successively thru 20 and 5 micron filters. Purified liquid sodium (reactant sodium) was introduced into the inlet of the disperser thru conduit 121 at temperature of about 180200 C. and at a rate of about 10 lbs./hr. The combined quantity of recycled solids and sodium fed provided about lbs. of material in the disperser all during operation. Average temperature in the disperser zone was about 165 C. Pitch of the conveyer paddles and the approximate 168 r.p.m. rotation of the conveyer shafts 13, rotating in opposite directions as in Example 1, maintained conditions of vigorous agitation and tumbling of material such that the dispersion zone was flooded above the level of shafts 13 and provided residence time of incremental portions of the dispersion in the disperser 107 of about 3 minutes. including the stoichiometric excess sodium contained in the recycled solids as fed into the disperser, the Na content of the dispersion, as continuously discharged in a freefiowing condition into transfer pipe was about 1.7% by weight. The relatively small cross-section of conduit 1.10 and the downflow of solids into reactor 108 formed a seal which prevented the presence of any significant amount of TiCl in the disperser 107.

Vaporized TiCl at temperature of about 220 C. Was fed continuously into the reactor 108 thru inlet pipe 111 at rate of about 20 lbs./hr., i.e. substantially the amount of TiCL; theoretically needed to react with the reactant sodium fed into disperser inlet 30. The total quantity of TiCL, introduced was such that, including the stoichiometric excess sodium content of the recycle and the reactant sodium fed into disperser inlet 121, in the reactor there was present about 15 lbs/hr. of Na in excess of that theoretically required to react with all the TiCl charged, that is, the reaction as a whole was carried out continuously in the presence of not less than about a by weight excess of sodium over theory. Exothermic rea tion took place,- and reaction zone temperature was within the range of 200 to 250 C. Residence time and conditions of highly vigorous agitation of solids in the reaction zone were about the same as in the disperser. Reactor product, which included make and recycled solids, was continuously discharged into reactor product receiver 113 at rate of about 1530 lbs/hr. and at temperature of about 225 C.

Such product was continuously fed into inlet 123 of heat exchanger 115 at a temperature of about 185 C. Heat transfer medium employed was conventional high temperature heat transfer oil. As in Example 1, the heat exchanger was jacketed and equipped with a screw conveyer provided with means for circulation of cooling medium therethru. Inlet temperature and flow of cooling medium thru the jacket and thru the conveyer, and rate of rotation of the conveyer were such that solids were discharged continuously into heat exchanger outlet pipe 125 at temperature of about 170 C. By suitable adjustmentof the valve in transfer conduit 125, about 1500 lbs./ hr. of solids were returned thru chute 117 to the disperser, the balance, constituting approximately the make, was run into reactor product collecting bin 120 at the rate of about 30 lbs./hr. This product analyzed by weight about 1.0% stoichiometric excess Na, with balance about 16.8% Ti and 82.2% NaCl (basis complete reduction of TiCl to metallic Ti). Weight ratio of recycle to total weight of fed T iCl and fed reactant Na was about 50/1. During the course of the run, there was added a relatively small but sufiicient additional amount of sodium above overall theoretical requirements to offset bleed loss sodium corresponding to the amount of stoichiometric excess sodium discharged into product collector bin 120 as a constituent of the make. By such procedure, the presence of the above noted 150% excess of sodium in the reaction zone 108 was maintained throughout the operation. The foregoing run was continuous without interruption, and no balling up of material or plugging of any of the apparatus occurred.

A 3 pound sample of product collected in bin 120 was placed in a retort similar to that of Fig. 4 in the argon blanketed manner already described. The retort and the material contained therein were placed in a gas-fired furnace and heated therein at temperature in the range of about 850 to 950 C. for a period of about 4 hours. The retort was removed from the furnace, cooled, opened to the air, and the solid residue was found to be substantially all shrunk away from the walls of compartment 97 and to be in the form approximately as indicated by the dotted line 82in Fig. 3. The mass was easily shaken loose from screen 95 and the lower periphery of retort section 92. Color was relatively light grey, and physical structure was cellular and more or less sponge-like. The quantity of sodium chloride which drained into retort bottom section 93 during furnacing was such that the solid residue recovered from retort chamber 97 contained about 50% by weight of metallic titanium and about 5 0% by weight of NaCl.

The'foregoing material was crushed to pass 6 mesh, leached 3 times with a 3% I-ICl solution, and then waterwashed about 4 times until filtrate was chloride-free. The water-washed material was then washed once with methyl .alcohol and once with ether, and dried at about 60 C. in

vacuum. The dried material analyzed by weight not less than 99.5% Ti, and contained not more than 0.2% oxygen,w0.05% nitrogen, and 0.05% carbon. Samples of this sponge product were arc-melted under an argon blanket, and the'resulting ingots had a Brinell hardness in the range-of 141-157, averaging 150.

Example 3.Operation was continued under substantially the same conditions as given in Example 2, and at the end of about another week, a sample of make" was processed-as described to sponge which was converted to ingot form having a Brinell hardness of 134 and contained 0.036% nitrogen.

We claim:

process for making metallic Ti involving a circuit comprising a dispersing zone for dispersing Na on solid finely divided carrier reaction product of a previous cycle, a separate reaction zone for reacting Na and TiCl to form metallic Ti, a recycle of carrier reaction product thru said zones in the order named, and separation from the circuit of reaction product formed during a cycle, the steps comprising providing a recycle carrier consisting of reaction product of a previous cycle and containing metallic Ti, NaCl and about 0.2-1.0% by weight of stoichiometric excess Na, introducing said carrier into said dispersion zone, feeding elemental Na in liquid form into said zone and dispersing the fed Na on said carrier while at temperature high enough to insure absence of solid sodium but not higher than about 200 C. and while in the absence of TiCl transferring the thus dispersed Na and carrier thereof into said reaction zone, feeding TiCl in vapor form into said reaction zone while in the absence of sodium from source other than said dispersing zone and maintained at temperature in the range of about 300 C. to effect formation of metallic Ti and NaCl from fed reactants, regulating relative amounts of Na and TiCl charged to provide a Na feed of about a stoichiometric quantity of Na on the basis of fed TiCL, plus a Na excess approximately corresponding to the amount of bleed loss Na contained in hereinafter separated cyclic make, regulating the amount of recycle charged into the dispersion zone so as to provide in the reaction zone a weight ratio of recycle to total weight of fed TiCl plus an approximately stoichiometric equivalent of fed Na substantially in the range of 60:1 to 33:1, discharging reaction mass from the reaction zone, separating from said mass reaction product in amount corresponding approximately to cyclic make, and recycling substantially the balance of said mass to the dispersion zone, the entire foregoing operation being carried out in an inert atmosphere.

2. In a multi-stage process for making metallic titanium involving low temperature reduction of titanium tetrachloride with elemental alkali metal, of the group consisting of sodium, potassium and NaK alloy, dispersed throughout a many times greater Weight bulk of finely divided substantially free-flowing solid carrier material of the group consisting of alkali metal chloride, metallic titanium and mixtures thereof, the improvement comprising dispersing elemental alkali metal in liquid form on the carrier material in a dispersing zone while held at temperature such as to maintain alkali metal in liquid form and high enough to insure absence of solid alkali metal and while maintaining the absence of titanium tetrachloride, thereafter transferring the thus dispersed elemental alkali metal and carrier material thereof from said dispersing zone into a separate reaction zone while in the absence of alkali metal from source other than said dispersing zone and While feeding titanium tetrachloride in vapor form into said reaction zone and while maintaining therein moderately elevated temperature substantially below the fusion point of the chloride of the reducing alkali metal but high enough to effect production of a reaction mass comprising metallic titanium and alkali metal chloride, and discharging said reaction mass from said reaction zone, the entire foregoing operation being carnamed, and separation from the circuit of reaction prod-- uct formed during a cycle, the steps comprising providing a recycle carrier. conslsting of reaction product of a previous cycle and containing metallic Ti and alkali metal chloride, introducing said carrier into said dispersion zone, feeding into said dispersion zone liquid elemental alkali metal, of the group consisting of Na, K and NaK alloy, the amount of metal being restricted so as to provide in the dispersion Zone a many times greater weight bulk of carrier, passing thru said dispersion zone said alkali metal and said carrier while held at temperature such as to maintain alkali metal in liquid form and high enough to insure the absence of solid alkali metal, and while in the absence of TiCL, and while under conditions of residence and vigorous agitation both sufficient to effect dispersion of said metal on said carrier, thereafter discharging the mass of thus-dispersed elemental metal and carrier from said dispersing zone and introducing said mass into said separate reaction zone, feeding into said reaction zone vaporous TiCl in quantity less than that theoretically needed to react with all the elemental alkali metal present, maintaining in said reaction zone moderately elevated temperature high enough to effect reduction of TiCl to metallic titanium and substantially below the fusion point of the chloride of the reducing alkali metal, passing the reactants thru said reaction zone while in the absence of alkali metal from source other than said dispersing zone and While under conditions of temperature, residence and vigorous agitation all sufiicient to elfect formation of a reaction mass comprising metallic Ti, alkali metal chloride and elemental alkali metal, discharging said reaction mass from the reaction zone, separating from said mass reaction product in amount corresponding substantially to cyclic make, and recycling substantially the balance of said mass to the dispersion zone, the entire foregoing operation being carried out in an inert atmosphere.

4. In a substantially continuous multistage cyclic process for making metallic Ti involving a circuit comprising a dispersing zone for dispersing alkali metal on solid finely divided carrier reaction product of a previous cycle, a separate reaction zone for reacting alkali metal and TiCl to form metallic Ti, a recycle of carrier reaction product thru said zones in the order named, and separation from the circuit of reaction product formed during a cycle, the steps comprising providing a recycle carrier consisting of reaction product of a previous cycle and containing metallic Ti and alkali metal chloride, introducing said carrier into said dispersion zone, feeding into said dispersion zone liquid elemental alkali metal, of the group consisting of Na, K and NaK alloy, the amount of metal being not substantially in excess of 3.5% by weight of total fed metal and carrier, passing thru said dispersion zone said alkali metal and said carrier while maintained at temperature not higher than about 200 C. but high enough to insure the abence of solid alkali metal, and while in the absence of TiCL, and while under conditions of residence and vigorous agitation both suflicient to effect dispersion of said metal on said carrier, thereafter discharging the mass of thus-dispersed elemental metal and carrier from said dispersing zone and introducing saidmass into said separate reaction zone, feeding into said reaction zone vaporous TiCl in quantity less than that theoretically needed to react with all the elemental alkali metal present, maintaining temperature in said reaction zone in the range of about 150-350 C., passing the reactants thru said reaction zone while in the absence of alkali metal from source other than said dispersing zone and while under conditions of residence and vigorous agitation both suificient to effect formation of a reaction mass comprising metallic Ti, alkali metal chloride and elemental alkali metal, discharging said reaction mass from the reaction zone, separating from said mass reaction product in amount corresponding substantially to cyclic make, and recycling substantially the balance of said mass to the dispersion zone, the entire foregoing operation being carried out in an inert atmosphere.

5; Ina substantially continuous multistage cyclic process for making metallic Ti involving a circuit comprising a dispersing zone for dispersing Na on solid finely divided carrier reaction product of a previous cycle, a separate reaction zone for reacting Na and TiCl to form metallic Ti, a recycle of carrier reaction product thru said zones in the order named, and separation from the circuit of reaction product formed during a cycle, the steps comprising providing a recycle carrier consisting of reaction product of a previous cycle and containing metallic Ti and NaCl, introducing said carrier into said dispersion zone, feeding elemental Na in liquid form into said zone, the amount of Na being not substantially in excess of 3.5% by weight of total fed Na and carrier, passing thru said dispersion zone said Na and said carrier while maintained at temperature not higher than about 200 C. but high enough to insure the absence of solid Na,

and While in the absence of TiCL; and while under con-' ditions of residence and vigorous agitation both sufficient to efiect dispersion of said Na on said carrier, thereafter discharging the mass of thus-dispersed elemental Na and carrier from said dispersing zone and introducing said mass into said separate reaction zone, feeding into said reaction zone vaporous TiCL; in quantity less than that theoretically needed to react with all the elemental Na. present, maintaining temperature in said reaction zone in the range of about ISO-350 C., passing the reactants thru said reaction zone while in the absence of sodium from source other than said dispersing zone and while under conditions of residence and vigorous agitation both sufficient to effect formation of a reaction mass comprising metallic Ti, NaCl and elemental Na, discharging said reaction mass from the reaction zone, separating from said mass reaction product in amount corresponding substantially to cyclic make, and recycling substantially the balance of said mass to the dispersion zone, the entire foregoing operation being carried out in an inert atmosphere.

6. The process of claim 5 in which the TiCl Na reaction is effected in the presence of at least 15% by weight of sodium in excess of that theoretically needed to reduce all of the TiCL, fed to metallic Ti.

7. The process of claim 5 in which the solid carrier reaction product contains suflicient sodium so that, in conjunction with fed sodium, the TiCl Na reaction is effected in the presence of about 15200% by Weight of sodium in excess of that theoretically needed to reduceall of the TiCl fed to metallic Ti.

8. The process of claim 5 in which the dispersed elemental sodium and carrier material thereof are discharged into the reaction than C., and reaction zone temperature is maintained in the range of about 300 C.

9. The process of claim 5 in which the solid carrier reaction product contains about 0.2'1.5% by weight of stoichiometric excess Na, the relative amounts of Na and' TiCL; charged are regulated to provide an Na feed of at least about a stoichiometric quantity of Na on the basis of fed TiCl and the amount of carrier charged into the dispersion zone is regulated so as to provide in the reaction zone a weight ratio of carrier to total weight of fed TiCl plus an approximately stoichiometric equivalent of fed Na substantially in the range of 60:1 to 25:1.

10. In a substantially continuous multi-stage cyclic process for making metallic Ti involving a circuit comprising a dispersing zone for dispersing carrier into said dispersion zone, feeding elemental Na" zone at temperature not less' Na on solid finely divided carrier reaction product of a previous; cycle, a separate reaction zone for reacting Na andin liquid form into said zone and dispersing the fed Na on said carrier While at temperature high enough to insure absence of solid sodium but not higher than about 200 C. and While in the absence of TiCl transferring the thus dispersed Na and carrier thereof into said reaction zone, feeding TiCl in vapor form into said reaction zone while in the absence of sodium from source other than said dispersing zone and maintained at temperature in the range of about ISO-350 C. to effect formation of metallic Ti and NaCl from fed reactants, regulating relative amounts of Na and TiCL, charged to provide a Na feed of about a stoichiometric quantity of Na on the basis of fed TiCl regulating the amount of recycle charged into the dispersion zone so as to provide in the reaction zone a weight ratio of recycle to total weight of fed T iCl plus an approximately stoichiometric equivalent of fed Na substantially in the range of 60:1 to 25:1, discharging reaction mass from the reaction zone, separating from said mass reaction product in amount corresponding approximately to cyclic make, and recycling substantially the balance of said mass to the dispersion zone, the entire foregoing operation being carried out in an inert atmosphere.

11. The process of claim 10 in which the dispersed elemental sodium and carrier thereof are discharged into the reaction zone at temperature not less than 125 C., and reaction zone temperature is maintained in the range of about 175-300 C.

12. The process of claim 10 in which the total amount of Na introduced into the system is in excess of theoretical Na requirements to an extent approximately corresponding with the amount of the bleed loss Na contained in the cyclic make and cyclically discharged from the circuit.

13. The process of claim 10 in which sodium and carrier in the dispersion zone and solids in the reaction zone are maintained in the forms of vigorously mechanically agitated contiguously constituted beds of substantially dry, free-flowing materials.

References Cited in the file of this patent UNITED STATES PATENTS 2,343,780 Lewis Mar. 7, 1944 2,481,226 Krebs Sept. 6, 1949 2,618,549 Glasser et a1 Nov. 18, 1952 2,618,550 Hampel et a1 Nov. 18, 1952 2,620,313 Odell Dec. 2, 1952 FOREIGN PATENTS 386,621 Great Britain Feb. 16, 1933 694,921 Great Britain July 29, 1953 717,930 Great Britain Nov. 3, 1954 1,069,706 France Feb. 17, 1954

Claims

2. IN A MULTI-STAGE PROCESS FOR MAKING METALLIC TATANIUM INVOLVING LOW TEMPERATURE REDUCTION OF TITANIUM TETRACHLORIDE WITH ELEMENTAL ALKALI METAL, OF THE GROUP CONSISTNG OF SODIUM, POTASSIUM AND NAK ALLOY, DISPERSED THROUGHOUT A MANY TIMES GREATER WEIGHT BULK OF FINELY DIVIDED SUBSTANTIALLY FREE-FLOWING SOLID CARRIER MATERIAL OF THE GROUP CONSISTING OF ALKALI METAL CHLORIDE, METALLIC TITANIUM AND MIXTURES THEREOF, THE IMPROVEMENT COMPRISING DISPERSING ELEMENTAL ALKALI METAL IN LIQUID FORM ON THE CARRIER MATERIAL IN A DISPERSING ZONE WHICL HELD AT TEMPERATURE SUCH AS TO MAINTAIN ALKALI METAL IN LIQUID FORM AND HIGH ENOUGH TO INSURE ABSENCE OF SOLID ALKALI METAL AND WHILE MAINTAINING THE ABSENCE OF TITANIUM TETRACHLORIDE, THEREAFTER TRANSFERRING THE THUS DISPERSED ELEMENTAL ALKALI METAL AND CARRIER MATERIAL THEREOF FROM SAID DISPERSING ZONE INTO A SEPARATE REACTION ZONE WHILE IN THE ABSENCE OF ALKALI METAL FROM SOURCE OTHER THAN SAID DISPERSING ZONE AND WHILE FEEDING TITANIUM TETRACHLORIDE IN VAPOR FORM INTO SAID REACTION ZONE AND WHILE MAINTAINING THEREIN MODERATELY ELEVATED TEMPERATURE SUBSTANTIALLY BELOW THE FUSION POINT OF THE CHLORIDE OF THE REDUCING ALKALI METAL BUT HIGH ENOUGH TO EFFECT PRODUCTION OF A REACTION MASS COMPRISING METALLIC TITANIUM AND ALKALI METAL CHLORIDE, AND DISCHARGING SAID REACTION MASS FROM SAID REACTION ZONE, THE ENTIRE FOREGOING OPERATION BEING CARRIED OUT IN AN INERT ATMOSPHERE.