US3022158A - Manufacture of metallic titanium - Google Patents

Description

Feb. 20, 1962 A. J. KALLFELz MANUFACTURE OF METALLIC TITANIUM 5 Sheets-Sheet 1 Filed Sept. 24, 1959 mmm INVENTOR ALOIS J. KALLFELZ ym, a, 1;, AT TO R N EY Feb. 20, 1962 A. J. KALLFELz MANUFACTURE or METALLIC TITANIUM Filed Sept. 24, 1959 3 Sheets-Sheet 2 ALIS J.KALL.FE.LZ

AT TORN EY Feb. 20, 1962 A. .1. KALLFELZ 3,022,158

MANUFACTURE OF METALLIC TITANIUM 5 Sheets-Sheet 3 Filed Sept. 24, 1959 a. @n ATTORNEY 3,022,158 MANUFACEIRE F METALLIC TETANIUM Alois l'. Kallfelz, Syracuse, NSY., .assigner to Allied Chemical Corporation, New York, NX., a corporation of New York Filed Sept. 24, 1959, Ser. No. 842,162 4 Claims. (Cl. 7S-84.5)

This invention relates to processes for making metallic titanium.

lThe prior art has proposed production of metallic titanium by reaction of metallic sodium and titanium tetrachloride by a two-stage operation involving'relatively low temperature reaction of TiCl4 and metallic sodium dispersed on a carrier to form a particulate reaction product comprising principally NaCl and metallic titanium in unstable form, followed by a high temperature stabilization procedure carried out at temperatures above the melting point of NaCl for the purpose of converting the initially unstable metallic titanium to titanium sponge which is stable in air. Processes of this type are disclosed for example in Hansley U.S.P. 2,824,799 of February 25, 1958, Quin U.S.P. 2,827,371 of March 18, 1958, and in Follows-Keene U.S.P. 2,882,144 of April 14, 1959. The Follows-Keene patent discloses a continuous method for carrying out the low temperature reac- V tion to form the low temperature reaction product containing sodium chloride and unstable metallic titanium.

According to prior art, the high temperature stabilization has been carried out as an expensive, time consuming, batch operation.

During high temperature stabilization, the physical forms of material present in the stabilizing zone include liquid NaCl, a pasty gummy mixture of partly melted rNaCl and solids, and solid granules or agglomerates of metallic titanium. Under most conditions, the mass undergoing stabilization is highly adherent to metal surfaces. The economic advantages of putting the stabilization step on a continuous basis are self-evident. However, because of the inherent gummy and relatively immobile characteristics of the material being stabilized, any continuous stabilizing apparatus of necessity involves use of mechanical facilities made of metal to carry or work the material undergoing stabilization thru the high temperature stabilization zone. However, the tenacity with which such material adheres to metal surfaces is so great that this factor of high adherence has been the major cause of frustration during attempts to develop satisfactory continuous stabilization. f

The prior art suggests carrying out the low temperature TiClr-dispersed Na reaction in such ways that the reaction product contains total sodium in a range varying from a few percent stoichiometric deficiency (i.e. an excess of TiCl4), to the stoichiometric equivalent, and thru a few percent sodium excessl over stoichiometric requirements. It will be understood that low temperature reaction product which may be made in accordance with prior art proposals contains Na of NaCl. there is some relatively small incomplete reaction, and in this situation the reaction product contains a small amount of subchlorides of Ti and a correspondingly small amount of unreacted stoichiometric sodium. If the reaction product was made under conditions in which sodium j was fed in quantity in small excess of stoichiometric refquirements, the reaction product contains, in addition toy Na of NaCl and any unreacted stoichiometric Na, a further quantity of Na in amount corresponding to such excess over stoichiometric. Hence, as used herein, the expression total sodium includes free and combined Na, i.e. NaV of NaCl, any unreacted stoichiometric Na which corresponds to small subchloride content, and any In most operationsV 3,622,158 Patentes Feb. zo, tesa Na which was charged to the low temperature reaction in excess of stoichiometric requirements for the TiCl4 fed. Free sodium designates Na in excess of stoichiometric Na, and excludes stoichiometric and unreacted Na.

Y Investigations on which the present invention are based show that successful continuous high temperature stabilization, looking mostly toward controlling the degree of adherence of material undergoing stabilization to metal equipment used in a continuous furnace and forming quality product, depends largely upon factors such as the physical form of the low temperature-reaction product to be stabilized, eg. whether particulate or otherwise, the total sodium content of the low temperature reaction product, and the temperature prevailing at the point where the stabilized material is finally removed mechanically from contact with the metal apparatus elements employed to continuously carry or work the material to be stabilized thru the stabilization Zone.

The object of this invention is to provide a process by which the unstable metallic titanium of Vmaterial consisting of a non-adherent particulate reaction product containing NaCl and unstable Ti, and having certain compositionsV with regard to total sodium content, and formed by dry-way reaction of metallic sodium and titanium tetrachloride at reaction elevated temperature above the melting point of sodium and substantially below the melting point of sodium chloride, may be continuously stabilized at temperature above the melting point of sodium chloride.

The invention, objects and advantages thereof, may be understood from consideration of the following description taken in conjunction with the accompanying drawings diagrammatically illustrating an embodiment of apparatus in which practice of the invention process may be effected. ln the drawings:

FIG. l is a vertical longitudinal section of a furnace adapted for Vcontinuous high temperature stabilization of the low temperature reaction product under consideration;

FIG. 2 shows mostly in elevation a cooler-crusher into which heat treated material from the furnace of FIG. 1 may be discharged, crushed and cooled;

FIG. 3 is a Vertical section taken the line 3 3 of FIG. l;

FIG. 4 is an enlarged sectional detail of apparatus for feeding material to be treated into one end of the furnace; and

FIG. 5 is an enlarged sectional detail of a seal for withdrawing` by-product sodium chloride as liquid from the furnace.

Referring to FIG. 1, 1li indicates an elongated openended muflie, circular in transverse vertical section, which may be made of any satisfactory heat and corrosion resistant material, such as Incoloy plate, of suitable thickness. The muiiie is provided with end plugs 11 and 12 which may consist of hollow metallic shells of Incoloy plate filled with insulating brick to the inner sides of which are attached electric grid- type heaters 13 and 14. The plugs are formed with flanges for bolting to the muflie ends'to make a gas-tight unit. Tubes 16 inthe end plugs accommodate sight glasses. The muiiie is provided on the top side with a solid material feed nozzle 18, a cleanout nozzle 19, and on the bottom side with a liquid salt (NaCl) discharge nozzle 21, a downwardly directed liquid salt drain pipe 23 (FIG. S), and a heattreated material discharge nozzle 24 (FIG. l) the bottom of which opens into a discharge leg 25 having on the lower periphery a flange 26.

FIG. 4 illustrates in vertical section an arrangement particularly adapted for use in conjunction with nozzle 18 (FIG. 1) for feeding solid particulate low temperature approximately on reaction product into mnflle 10. The feeder of FIG. 4 may comprise a casting including a vertical annular boss 3l) integral with a circular ange 31 adapted to be bolted to flange 33 of nozzle 18. Welded to the underside of boss 30 is a depending feedrtube 35 in axial alignment with the cylindrical passage in boss 30. A cylindrical casing 36 surrounds tube 35'and extends from the underside of boss 30 to the bottom end of tube 35. As seen in FIG. 4, boss 30 and ange 31 are provided with an air inlet conduit 39 and an air outlet conduit 40, inlet conduit 39 being extended by a tube 41 to approximately the lower end of the annulus surrounding inlet tube 35. The arrangement described affords forced air cooling of all that portion of the feeder exposed to the high temperature atmosphere existing in mule 10. Solid materialis fed into the upper end of feed tube 35 via conduit 43 the upper end of whichmay be flange connected to the discharge end of a screw conveyor, not shown, which transfers particulate low temperature reaction product from a storage bin to the feeder of FIG. 4. A flanged nipple 44, located in axial alignment with tube 35, facilitates rodding of tube 35 in case of plugging.

FIG. shows a liquid salt drain and a gas seal for the munie. The bottom of the mule is formed so as to provide gentle slopes from the muflle ends to mufe drain pipe 23 which projects downwardly into a cup 47 tapered to a point at the bottom. Similarly tapered rod 48 depends from the under end of the taper point. The upper outer end of the cup 47 may be welded, as by spaced apart webs 59, to the upper end of a cylindrical sleeve 51 the lower end of which terminates in a ange 53 for attachment to flange 5d on the bottom of nozzle 21. According to this arrangement, liquid salt lls cup 47, overflows the upper periphery thereof, and runs down thru the annulus 55 between the outer surface of the cup and the inside of the upper end of sleeve 51. Liquid salt collecting in the cup forms a gas seal, and liquid salt in annulus 55 is discharged therefrom via rod 48 and funnel 56 which cooperate to minimize contact of liquid salt with the inner face of the lower end of sleeve 51 which opens into a liquid salt receptacle not shown.

The heat-treated material discharge nozzle 24 (FIG. l) may be rectangular in horizontal section and tapered substantially toward the bottom end which opens into discharge leg 25 of elliptical horizontal section. The upper edge of nozzle 24 may be welded to the edge of a corresponding opening in the mule shell, and near the lower end nozzle 24 has welded thereto the upper periphery of an inverted cone-like apron 60 the lower edge of which is welded to the upper end of the discharge leg 25. As shown in FIG. l, the lower end of nozzle 24 projects down into the upper end of discharge leg 25, and configuration of the adjacent parts is such as to afford a substantial annulus between the bottom of the discharge nozzle and the inside of the discharge leg, this arrangement being preferred in order to prevent direct contact, with the walls of discharge leg 25, of hot material discharged thm the nozzle 24.

The mule (FIG. l), nozzles 18, 19, 21 and 24, and discharge leg are enclosed in an electric furnace assembly comprising an outer steel shell 63, and insulating rebrick 64 the inner surfaces of which are sufficiently spaced from` the exteriors of the mule, the salt drain, discharge nozzle 24 and the discharge leg 25 to accommodate electric grid-type heaters 66. These heaters, and also heaters 13 and 14 in the end plugs,tare arranged in suitable unit relation so that variable amounts and degrees of heat, as desired, may be applied to different parts of the apparatus.

Mufe 10 is provided with an axially disposed endless conveyor extending from beneath feed nozzle 18 to solid material discharge nozzle 24. Since the mechanical structural details of the conveyor constitute no part of this invention, for brevity, conveyor construction illus? trated in the drawings is highly diagrammatic. As indi- 579 of January 29, 1957.

cated in FIG. 3, longitudinally disposed angle irons or rails 70 are welded at their edges to the lower inner cir cumference of the muiile and afford support for the conveyor and associated elements, In FIG. 3, 71 denotes generally a longitudinal framework which extends axially of the muie and to which in one way or another all elements of the conveyor assembly are xedly or movably attached. Lower and upper tracks 73 and 74 support and guide the edges of an endless conveyor belt 75 equipped at the longitudinal outer edges with selvage plates 77, fabricated as known in the conveyor art and functioning to prevent spilling of solid material over the edges of the upper run of the belt.

Suitablyjournalled in association with the conveyor frame 71 are shafts 78 and 79 (FG. l) carrying belt drive drums. One end of each drive shaft projects outwardly thru the furnace shell and thru gas-tight glands to facilitate connection to the source of power for rotating the shafts and the associated belt drive drums. Mulfle 10 is anchored at the material feed end, and the entire conveyor unit is preferably anchored at the solids discharge end of the mutlle while the feed end of the conveyor assembly is free to move axially to provide for varying thermal conditions of expansion and contraction. Further, feed end shaft 78 is mounted so as to permit axial movement with regard to the conveyor frame, the bearings of shaft 78 being yoked to the inner vend of a rod 6l (FIG. 1) which is axially movable in gas-tight gland 82. The outer end of rod $1 may be connected to any suitable mechanism, not shown, by which tension of the endless belt may be observed and adjusted. Preferably both shafts 73 and 79 are driven members so that the belt is driven from both ends.

The belt drive drums may be cast out of type ACI-HT stainless steel and provided with lug teeth spanning the width of the drums. The belt preferably employed is of the plate type, as distinguished from mesh type, known in the art and illustrated for example in U.S.P. 2,779,-

Preferably, construction of the plate belt is such that the inner and outer surfaces of the plates are concavcd and convexed respectively in accordance with the curvature of the drive drums. The belt plates, belt pins and selvage plates may be made of ACI-HT stainless steel (Ni 35--Cr l5). Plate type belts are more or less perforate at the plate and pin linkages, and permit drainage of liquid NaCl thru both upper and lower belt runs.

A scraper blade 85 (FIG. l) which may be made of c g. 9%1" No. 330 stainless steel plate, is attached rigidly to the end of the conveyor frame in position as to extend over the entire width of the belt. The blade is provided with a bevel knife edge, and is attached to the frame so that the knife edge is preferably tangential of the belt at a point slightly above the horizontal center line of the drum.

Heat treated material, i.e. spalt, `is discharged from the conveyor belt thru discharge nozzle 24 and discharge leg 25 of FIG. l into a cooler-Crusher shown diagrammatically in FIG. 2. The cooler-Crusher assembly comprises a cylindrical steel shell housing a rotating shaft 91 mounted in gas-tight bearings and carrying steel spud paddles 93. Stationary stud paddles 94 are welded at their lower ends to the cooler shell to facilitate crushlng. An inlet nozzle 96 of eliptical horizontal section provided with a flange 97 for connection to flange 26, affords communication between the bottom of furnace discharge leg 25 and the interior of Crusher-cooler 90.`

Disintegrated solids discharged from the crusher-cooler drop thru an outlet nozzle 99 into a gas-lock chamber 100 outlet of which communicates with a spalt cooling bin 102 which is one of a plurality of parallelly arranged similar bins. TheV entire cooler-Crusher assembly may rest on spring supports 10d to permit vertical expansion, and on roller bearings indicated at to allow for hori z'ontal movement.

-It will be understood that the interior of the apparatus described is gas-tight, and that in operation the interior of the entire apparatus, from the interior of the storage bin for the unstable low temperature reaction product up to and including cooling bin 102, is maintained under a relatively low positive pressure of an inert gas e.g. argon, accessories such as piping, valves, inlets, etc. for maintaining an inert atmosphere within the apparatus not being shown. Selection of construction materials not mentioned herein are within the skill of the art.

One control factor of major importance in successful continuous stabilization of particulate low temperature reaction product is the composition of the latter with regard to the presence or absence of free Na. For convenience, this control factor is referred to herein as titre. Positive titre designates a low temperature reaction product containing some free sodium in excess of stoichiometric requirements, it being kept in mind that stoichiometric Na includes both reacted and unreacted stoichiometric Na. Neutral titre designates a low temperature reaction product which contains a substantially stoichiometric quantity of Na, while negative titre designates a reaction product containing a deiiciency of stoichiometric Na, i.e. the product which is short of stoichiof metric Na and from another viewpoint may be considered as containing excess TiCl4. Titre of any given sample may be determined by any suitable analysis method which takes into account all sodium present except the reacted sodiumwhich has gone over to NaCl in the low temperature reaction. To illustrate, and assuming a sample having a positive titre (i.e. contains Na'above stoichiometric requirements), the sampie may be treated with Vwater and e.g. hydrochloric acid in excess. On addition of Water, the unreacted Na goes to NaOH and the corresponding amounts of titanium chlorides hydrolyze to TiOZ and HCl, the HCl tying up with the NaOH to form NaCl. Thuswise, in the case of a sample containing an excess of Na over stoichiometric, the unreacted Na is eliminated from further consideration. With regard to thetNa present over and above stoichiometric, such Na with Water goes to NaOH, and the latter reacting with a known amount of HCl in excess goes to NaCl plus the HC1 excess. Back titration with NaOH to neutralize the excess HCl gives the amount of HCl used to tie up with the Na present over and above stoichiometric requirements, this amount of Na being then determinable on a weight basis. The relation between thisV thus determined weight and the theoretical stoichiometric amount of Na in the given sample provides a percentage valuel denoting the excess of sodium over stoichiometric and indicated hereinras positive percent titre, e.g. a positive 1% titre indicates that the sample as to Na contains an excess of 1% by weight of stoichiometric Na requirements. Similarly, assuming a low temperature reaction product deficient in stoichiometric Na, on treatment of the sample with water and hydrochloric acid, the unreacted Na vand the corresponding amounts of titanium Vchlorides go Yto NaCl as before. However, because of stoichiometric Nar4 deficiency there is formed Va corresponding amount of HCl which amount is the difference between total HC1 present and the HC1 added to the sample with the water. The amount of Na reactable with the thus formed HC1 to produce NaCl is the weight measure of the stoichiometric deficiencyof Na, and the weight relation of such amount of Na to the theoretical stoichiometric amount of Na in the sample gives a negative percent titre, c g. a negative 1% titre indicates that the sample as to Na is short 1% by Weight of stoichiometric Na requirements.

1 According to the invention, it has been found that low Vtemperature reaction product in particulate form may be continuously stabilized, by passing the same ona suitable metal supporting sur/face moving thru a stabilization zone Ymaintained at stabilizing temperature and for an adequate retention time, and may be'satisfactorily disengaged from a metal supporting surface providedY that the' particulate low temperature reaction product is of such composition as to total sodium as to have a titre in the range of substantially neutral up to a relatively lsmall positive value, and provided that the temperature in the zone of disengagement of the stabilized material from the moving surface, on termination of retention time, is maintained above the melting point of sodium chloride. Brieiiy, practice of the invention comprises continuously feeding the low temperature reaction product material-in nonadherent particulate form and having a titre in the range of substantially neutral to a positive va'lue--into one end of a high temperature stabilizing zone `and onto a sup-`V porting surface continuously moving thru said zone, continuously moving said surface and the material thereon thm said zone while subjectingsaid material to stabilizing temperature substantially above the melting point of sodium chloride, regulating rate of movement of said surface and of said material thru said zone so as to provide a retention time for said material such that, on discharge from said zone of said material and cooling thereof to relatively low temperature, the metallic titanium content of said cooled material is stable in air, continuously disengaging said heat-treated solid material from said surface on termination of said retention time while maintaining temperature above theinelting point of sodium chloride in the zone of said disengagement, and continuously withdrawing disengaged solid material from said zone, the entire foregoing operation being' carried out in an inert atmosphere.

With regard to the low temperature reaction product utilized, the invention process is directed to stabilizing the chloride. While the reaction temperatures employed in` the manufacture of the low temperature reaction product may range from above the melting point of sodiumgto a temperature reasonably below the melting point of sodium chloride, such temperatures are more practicably in the approximate range of -650" C., it being preferred, in practice of the instant invention, to utilize low temperature reaction product which has been made in the temperature range of 175 C. up to say 30D-400 C.

As above indicated, it has been found that inrorder to continuously stabilize low temperature reaction product when in the non-adherent particulate form, such product should contain at least a stoichiometric quantity of total sodium, i.e. a titre not substantially below zero. It has further been found that, in order to facilitate and enhance disengagement of stabilized material from moving metal surfaces on which the material has been carried thru the stabilization zone, the low temperature reaction product may and preferably should have a titre on the positive side. Thus, the particulate low temperature reaction products employed have titres in the range of about zero (or neutral) up to about al plus 2% titre. Quantities of total sodium such that the particulate'product has 'a Atitre higher than about-2% are undesirable since investigations indicate that greater excess sodium values afford no significantly increased disengagement properties, and in some instances appear to deleteriously affect Brinell hardness number of the ultimate metallic titanium product. For good working conditions with regard to disengagement properties and low Brinell hardness, the reaction product being stabilized should have a ktitre abovey zero, `and preferably in the positive titre range of 0.2-1.25 best quality product being obtained with positive titre of AVabout 0.2-03

aoaarae Y scribed, e.g. via a feed device such as exemplified in FIG. 4.

Stabilization temperature is above the melting point (804 C.) of sodium chloride, a practicable Working low temperature limit being about 850 C. Stabilization temperature may vary within the range of about 850- l000 C., although average temperatures of around 900 C. are preferred, and temperatures above about 950 C. are undesirable because of increased tendency for Spalt to adhere to and incipiently alloy with metal of the conveying surface.

The particulate material as fed into the stabilizing zone is relatively cold, as compared to stabilizing temperatures, although to facilitate transfer from a storage bin to the stabilizing furnace feed device, incoming material may be heated to temperature of say l`C. Sudden introduction of relatively cold low temperature product into the high temperature atmosphere of the Stabilizer creates feeding difficulties characterized by two factors. Ternperatures in the stabilizing zone are either above the boiling point of metallic sodium or at least sufficiently high so that metallic sodium present has substantial vapor pressure. Thus, it has been found that even when the material fed to the stabilizer has low metallic sodium content, if parts of the feed device are permitted to run relatively cold, sodium tends to condense and solidify in and around the feed inlet and enhance plugging. Further, experience shows that on sustained runs, if the feed device is permitted to become heated to about the Stabilization temperature, some of the lines contained in the low temperature reaction product tend more or less to immediately stabilize and bridge over the feed inlet end with a solid sinter. In accordance with the present improvements, cold air is forced thru a feeder such as that ,of FIG. 4 in such a Way as to maintain the temperature of the feed mechanism in nozzle l@ and of the atmosphere immediately adjacent to the feed inlet end, approximately in the range of 20G-500 C. This procedure minimizes solidication of sodium and premature stabilization of titanium and correspondingly minimizes plugging.

Particulate material fed into the stabilizer drops onto the receiving end of the moving supporting surface eg. the belt and spreads out in relatively layer form mowing up at the center of the belt and tapering off at the edges. In usual practice as described herein, the material on the belt may be about 6 in. deep at the center and about 1/2 in. deep toward the edges. As is apparent, there is no relative movement between the belt and the material thereon, durin .,7 passage of the material and the supporting belt thru the stabilizing zone.

Retention time of material being stabilized in the stabilizing zone is variable as is appreciated by the skill of the art. In any event, retention time is such that the metallic Ti content of the splat produced in and discharged from the stabilizing zone, when cooled to relatively low temperatures, is stable in air. W.th this objective in view, depending upon the capacity of the particular apparatus at hand, desirable stabilizing temperature and other operating factors apparent to the skill of the art, rate of movement of material to be stabilized thru the stabilizing zone and retention time therein may be established by test run for any given set of conditions. In procedures such as exemplified herein, retention time preferably should be not less than 3 hours. Temperature to which the spalt should be cooled before exposure to air, e.g. spalt collecting in the spalt cooling bin 102 of FIG. 2, may lie in the range of from say 40-80 C. and preferably in not more than 100 C.

v A marked advantage resulting fromherein continuous stabilizat'on is that by-product NaCl may be continuously drained from solids or semi-solids all during the passage of the same thru the stabilization zone, drainage being enhanced by the perforate plate type belt preferably employed. Much of the by-product NaCl sepa- Ulf.

rates out as liquid as soon as melted, thus facilitating creation of semi-cellular structure in residual material on the belt which in turn further facilitates access of heat and drainage of more liquid NaCl. In practice as exemplied about 60 to 75% of the total salt content of the material fed may be drained away and separately removed frorn the system.

In addition to the previously described compositions of the material fed to the stabilizing zone, it has been found that, with respect to providing satisfactory conditions for disengagement of spalt from its supporting surface at the end of retention time, another equally important and controlling factor lies in the temperature `existing in the zone of disengagement of the Spalt from the metal supporting surface. In this connection, it has been found that the zone at and in the immediate vicinity of spalt disengagement should be maintained at a temperature above the melting point of NaCl. This temperature may be less than the average stabilization temperature, but in any case as a practicable minimum should be a workable number of degrees C. above the melting point of NaCl, and ordinarily should not be less than about S30-850 C. While such temperatures are needed in the immediate zone of disengagement of spalt from the supporting surface, comparable temperatures are desirably maintained while the spalt is being transferred e.g. thru the discharge nozzle 24 and discharge leg 25 of FIG. 1 into a Crusher-cooler, such temperatures preventing build up of solidified NaCl until' the spalt is delivered into a crushing and cooling zone such as illustrated in FIG. 2.

The following example illustrates practice of the inventon. The apparatus employed was substantially the same as described. In the muffle, a plate-type continuous belt about 15 inches wide was used. The length of the belt, strung over 10 in. O.D. drive drums, was such that the drum drive shafts were about 9 ft. apart (cold furnace). Data given are based on averages of a 20-day continuous run.

The low temperature Na-TiCl4 reaction product subjected to stabilization was made in a conjunctive continuous run in accordance wlth the process described in the above-mentioned Follows-Keene patent. ln the low temperature reaction vaporous TiCl4 and sodium dispersed on reaction product of a previous cycle were reacted at temperatures in the range of about 230-260 C. This reaction product consisted of 12-14% unstable metallic Ti, the balance including relatively small amount of subchlor'des of titanium and a corresponding small amount of unreacted sodium, sodium in excess of stoichiometric requirements amounting to a titre value in the range of 0.5-l%, the remainder, the weight bulk of the material, being sodium chloride. A typical screen analysis is as follows:

The low temperature product was made and maintained under an argon blanket.

The free-flowing, particulate low temperature reaction product was transferred under argon blanket from a storage bin by a screw conveyor, held` at internal temperature of about C., to the stab'lizing furnace feed inlet such as conduit 43 of drawing FIG.`1. By forced cold air circulation thru the feed device, substantiallyias described in connection with drawing FIG. 4, the entire feedjunit especially at the outlet end was kept at temperatures approximately in therange of 200-500C. Rate of feed of low temperature reaction product to the stabflizing furnace was such that 30-40 lbs/hr. of incoming unstabilized material was dropped onto thereceiving end of the belt conveyor. .The depth of solid material on the belt near the feed end was about 6 in. at the center of the belt, tapering oit to about 1/t in. near the belt edges. Electrically generated heat was applied to the mutlie in quantity such that temperature throughout the muille and in the zone of disengagement of spalt at the discharge end of the belt was maintafned at about 900 C. Temperature in the spalt discharge nozzle 24 and in the furnace discharge leg 25 was permitted to drop olf somewhat but was maintained several degrees above the 804 C. melting point of NaCl. The material on the belt was forwarded thru the stabilizing zone at the rate of about 2 ft./hr., thus providing an overall retention time of titanium material on the belt of about 4.5

hrs.

During this period 15-20 lbs/hr. of liquid NaCl drained away from the material on the belt, flowed into the salt seal in the bottom of the Inutile and was discharged from the apparatus. Hence, about 60 to 75 weight percent of the total NaCl present in the stabilizing zone drained away from the material on the belt and was removed from the system as liquid NaCl. Spalt was satisfactorily stripped from the end of the belt by means of a scraper blade positioned, with respect to 4the belt, substantially as previously described. Stripped spalt dropped thru the discharge nozzle 24 and the discharge leg 25 into the cooler-crusher. Rate of discharge of spalt olf the belt was ,l5-20 lbs/hr., and the spalt contained in the range of Z50-40% metallic titanium. In the cooler-Crusher, the paddle shaft was driven at a rate of about 100 rpm., and the spalt was broken up into chunks of about 11/2 in. maximum dimension, i.e. small enough to be handleable in the succeeding operation. The broken spalt product of the cooler-Crusher was conveyed to and dropped into one of a plurality of parallelly arranged cooling chambers which when filled was isolated in the cooler-crusher atmosphere. In-the cooling chamber, the material was allowed to cool to about 40 C. Up to this point, the entire stabilizing operation was carried out under a positive pressure of argon of about 3-4 in. of water.

On completion of cooling, the argon blanket was released and the metallic titanium of the spalt was stable in air. The spalt was then crushed to maximum size of about 3/8 in., typical screen analysis being- Mesh size: Wt. percent retained :Vs in 28.6

1A in 23.5 +20 mesh 37.8v -20 mesh 10.1

The spalt was salt leached by washing 3 times in water containing about 1% of HCl, the quantity of acidied water used in each wash being roughly 1.25 times the weight of solids. The residual, stable metallic titanium sponge was vacuum dried at temperature not in excess of about 100 C. After arc melting, as known in the art, the metallic titanium product had average Brinell hardness number of 145.

In the course of the run about 14,000 lbs. of low temperature reaction product of bulk density of about 70-75 lbs/ft.3 were fed to the stabilizing furnace; about 7700 lbs. of NaCl were drained out as liquid thru the salt seal; about 6300 lbs. of spalt (crushed bulk density about 103 lbs./ft.3) were discharged from the belt; and sponge titanium recovery was about 2100 lbs., i.e. about 88-89% of theory. Bulk density of the sponge was about 66 lbs./ ft. In other runs similar to the above, metallic titanium having Brinell hardness approximately in the range of 125-150 has been produced.

I claim:

1. The process for continuously stabilizing Ithe unstable metallic titanium of material consisting of a non-adherent particulatereaction product containing NaCl and unstable Ti and formed by dry-way reaction' of metallic Na and TiCl., at reactive elevated temperature above the melting point of Na and substantially below the melting point of NaCl, which process comprises continuously feeding said material-in non-adherent free-tlowing particulate form and having titre substantially in the range of zero up to positive 2%-through a feed nozzle into one end of a high temperature stabilizing zone and onto a supporting surface continuously moving thru said zone, maintaining temperature within the feed nozzle and of the atmosphere immediately adjacent the feed end thereof in the range of about ZOO-500 C., continuously moving said surface and the material thereon thru said zone while subjecting said material to stabilizing temperature above the melting point of NaCl, regulating rate of movement of said surface and of said material thru Vsaid zone so as to provide a retention time for said material such that, o'n discharge from said zone of said material and cooling thereof to temperature not substantially higher than 100 C., the metallic Ti content of said cooled material is stable in air, continuously draining liquid NaCl away from said material during passage thereof thru said zone and continuously separately discharging such liquid from said zone, and, on termination of said retention time, mechanically disengaging said heat-treated solid material from said s urface while maintaining temperature above the melting point of NaCl in the zone of said disengagement, the entire foregoing operation being carried out in an inert atmosphere.

2. The process of claim 1 in which titre value is substantially in the range of positive 0.2-1.25%.

3. The process of claim l in which titre value is positive but not in excess of positive 2%.

4. The process for continuously stabilizing the unstable metallic titanium of material consisting of a non-adherent particulate reaction product containing NaCl and unstable Ti and formed by dry-way reaction of metallic Na and TiCl4 at reactive elevated temperature above the melting point of Na and substantially below the melting point of NaCl, which process comprises continuously feeding said material-in non-adherent free-flowing particulate form and having titre substantially in the range of positive 0.2-1.25 %through a feed nozzle into one end of a high temperature stabilizing zone and onto a supporting surface continuously moving thru said zone, maintaining temperature within the feed nozzle and of the atmosphere immediately adjacent the feed end thereof in the rangel of about 20D-500 C., continuously moving said surface and the material thereon thru said zone while subjecting said material to stabilizing temperature not less than 850 C., regulating rate of movement of said surface and of said material thru said zone so as to provide a retention time for said material not less than 3 hours but such that, on discharge from said zone of said material and cooling thereof to temperature not substantially higher than C., the metallic Ti content of said cooled material is stable in air, continuously draining liquid NaCl away from said material during passage thereof thru said zone and continuously separately discharging such liquid from said zone, and, on termination of said retention time, mechanically disengagiug said heat-treated solid material from said surface while maintaining temperature above the melting point of NaCl in the zone of said disengagement, the entire foregoing operation being carried out in an inert atmosphere.

(References on foiiowing page) 11 References Cited in the le of this patent 2,882,144 UNITED STATES PATENTS 2,564,337 Maddex Aug. 14, 1951 2,734,244 Herres Feb. 14, 1956 5 2,827,371 Quin Mar. 18, 1958 720,517 r2,861,791

Chshulm et al. NOV. 25, 1958 12 Fo11ows et a1. Apr. 14, 1959 Lynskey July 21, 1959 Quinn July 12, 196() FOREGN PATENTS Great Britain Dec. 22, 1954

Claims (1)

1. THE PROCESS FOR CONTINUOUSLY STABILIZING THE UNSTABLE METALLIC TITANIUM OF MATERIAL CONSITING OF A NON-ADHERENT PARTICULATE REACTION PRODUCT CONTAINING N2CL AND UNSTABLE TI AND FORMED BY DRY-WAY REACTION OF METALLIC NA AND TICL4 AT REACTIVE ELEVATED TEMPERATURE ABOVE THE MELTING POINT OF NA AND SUBSTANTIALLY BELOW THE MELTING POINT OF NACL, WHICH PROCESS COMPRISES CONTINUOUSLY FEEDING SAID MATERIAL-IN NON-ADHERENT FREE-FLOWING PARTICULATE FORM AND HAVING TITRE SUBSTANTIALLY IN THE RANGE OF ZERO UP TO POSITIVE 2%-THROUGH A FEED NOZZLE INTO ONE END OF A HIGH TEMPERATURE STABILIZING ZONE AND ONTO A SUPPORTING SURFACE CONTINUOUSLY MOVING THRU SAID ZONE, MAINTAINING TEMPERATURE WITHIN THE FEED NOZZLE AND OF THE ATMOSPHERE IMMEDIATELY ADJACENT THE FEED END THEREOF IN THE RANGE OF ABOUT 200-500*C., CONTINUOUSLY MOVING SAID SURFACE AND THE MATERIAL THEREON THRU SAID ZONE WHILE SUBJECTING SAID MATERIAL TO STABILIZIANG TEMPERATURE ABOVE THE MELTING POINT OF NACL, REGULATING RATE OF MOVEMENT OF SAID SURFACE AND OF SAID MATERIAL THRU SAID ZONE SO AS TO PROVIDE A RETENTION TIME FOR SAID MATERIAL SUCH THAT, ON DISCHARGE FROM SAID ZONE OF SAID MATERIAL AND COOLING THEREOF TO TEMPERATURE NOT SUBSTANTIALLY HIGHER THAN 100*C., THE METALLIC TI CONTENT OF SAID COOLED MATERIAL IS STABLE IN AIR, CONTINUOUSLY DRAINING LIQUID NACL AWAY FROM SAID MATERIAL DURING PASSAGE THEREOF THRU SAOD ZONE AND CONTINUOUSLY SEPARATELY DISCHARGING SUCH LIQUID FROM SAIS ZONE, AND, ON TERMINATION OF SAID RETENTION TIME, MECHANICALLY DISENGAGING SAID HEAT-TREATED SOLID MATERIAL FROM SAID SURFACE WHILE MAINTAINING TEMPERATURE ABOVE THE MELTING POINT OF NACL IN THE ZONE OF SAID DISENGAGMENT, THE ENTIRE FOREGOING OPERATION BEING CARRIED OUT IN AN INERT ATMOSPHERE.

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