US 2868703 A
Description (OCR text may contain errors)
Jan. 143, 1959 E. WAINER 2,868,703
CELL FEED MATERIAL FOR THE PRODUCTION oE TITANIUM Fild Nov. 8, 1954 Eugene Wainer BYa/Mja.
2,868,708 ...-Petented Jan.13, 19.59
CELL FEED MATERIAL FR THE PRODUCTION OF TITANIUNI t Eugene Wainer, Cleveland Heights, himassignor, by rnesne assignments, to Horizons Titanium Corporation, Princeton, N. J., a corporation of New Jersey Application November S, 1954, Serial No. 467,581*y 2 Claims. (Cl. 204464) This invention relates to a thermal method of preparing an alloy consisting principally of titanium with minor but definite proportions of carbon and oxygen, which is particularly usefulin the production of pure titanium.
Many methods have been proposed for the production of pure titanium metal which may be grouped generally as pyrometallurgical, chemical and electrolytic. Each method suffers from serious disadvantages either as to the raw materials which are necessary, or the temperatures at which the desired reactions take place. Of` the three approaches, the electrolytic winning of titanium metal from various compounds appears to offer the simplest and most economical solution of the problem.
Electrolytic techniques may be conveniently classified according to the electrolyte as aqueous or non-aqueous. No successful deposition of titanium from an aqueous bath has been reported to date, but several non-aqueous baths have been successfully'operated to produce the metal. The use of a fused salt bath consisting essentially of one or more halide salts of the alkalimetals or alkaline earth metals together with a simple or complex halide of In an earlier filed applicationY Serial No'.'320,ll3, which any of -a number of well-known processes... lt may bey ture and space grouping'and nearly the same latticelsize,
they arecapable of forming a continuous series of'solid solutions kranging fromjpure titanium carbide to pure titanium monoxideujwhen the individual components` are intimately nnxedA and subsequently heated to an ap-` propriate elevated temperature under a reduced pressure, the two components forma mutual solid solution from which, because 'of he reduced pressure, carbon monoxide tends to. be eliminated.
The titaniuml carbide employed may be preparedproduced by reacting pureor pigment. grade titanium di: oxide (T102) in finely divided form (-325 mesh Tyler standard)` `with, pure carbon (prepared by calcining lampf,V black)` under carefully controlled conditions so that the` titanium dioxide is successively convertedto Ti3O5, Ti203,
i -TiO and finally to TviC, the reaction at each of the stages issued on November l, 1955, as Patent 2,722,509, I have '-tz disclosed a process wherein the electrolytic recovery of titanium is effected in a fused saltbath from mutual solid solutions of titanium carbide and titanium monoxide. The present application is a continuation in part of `Serial No. 320,113 and is directed to the method of preparation of a novel composition of matter serving as the source of titanium.
In another of my copending applications Serial No. 398,192, there is described a' process in which titanium is deposited cathodically from a bath in which titanium carbide or mutual solidsolutions of titanium carbidev and titanium monoxide are chlorinated in situ by suitable chlorinating agents.
In still another copending application Serial No. 398,193 tiled by John T. Burwell, Jr., and Quentin H. McKenna,
y a process is disclosed wherein a transition metal is electrolytically'deposited at a cathode from a salt bath prepared by reacting in a fused halide salt medium, atransitaking placebetween solid materials. The amount of carbon employedshoull be slightly in excess of the stoichiometric amount requiredfor the complete conversionfof TiO2 .to'f1`iC-The vproduct obtained is substantially pure TiC. If Vfurther purification is desired the TiC mayk be,4 crushed and any extraneous materials separated leavingA a pure TiC suitable for reaction with the titanium mon oxide'. t
The titanium monoxide may kbe prepared in any knowny manner; It may be .prepared from titanium carbide in the manner taught inv cachot U. S. Patents 2,681,847@
2,681,848.01- 2,681,849.` I prefer to follow the practice i described lin a copending application Serial No. 369,511,`
which issued on VJune 12,'1956,.as Patent 2,750,259, whereinapr'o'cess' i's' disclosed i n which titanium dioxide (TiOz) is converted'r lirs't to' `vtitanium sesquioxide (Ti-203) nand".
theses'quioxide is furtherreacted to produce titanium monoxide '(TiO). Thetir's't step in the conversion is carriedout by heatingna mixture of carbon and titanium dioxide to 'a temperature inthe range'between ll00 C.
and 1200 C. while. removing the carbon monoxide from the reaction zone as vrapidlyfas it forms. The formation of y the monoxide is accomplished by heating a prepared mixture of the' s'esquiox'ide` and lcarbon in stoichiometric prov portions to temperatures between 1500" C. and l750 C.
tion metal carbide or solid solution of transition metalv carbide and monoxide such as those of titanium with a transition metal halide. l
Itis one object of this invention to provide an improved cell feed material for processes such as those described. The cell feed material may, it will be noted, be a consumable anode, or a constituent of the electrolytic bath, or a material employed in the preparationA of the bath.
Itis another object of the invention to provide `a process for preparingthe novel `cell feed material.
These and other objects are readily accomplished by bringing together titanium carbide and titanium monoxide under suitable` reaction conditions. inasmuch as4 titanium carbide and titanium monoxide have the same cubic strucwhile removing the carbon monoxide as it forms either' by sweeping the furnacev with an inert gas such as argon,
or by activevacuum pumping; The titanium' monoxide so produced may, as described in the above-notedl patent application, be further heated to above 1800 C. to pro-` I ducea fused product admirablyk suited to be reacted with titanium carbide;
In preparing both` the titanium carbide and the titanium i monoxide' asabove'described, it will be noted that the reactionsoccurredfbetween materials in the solid state',k, and it willlbe further noted that there are obtained rela"- tivelypur'e"compoundsof titanium and oxygen or titanium and carbon by 'carrying out the reactions under carelfully controlled conditions. l Although I presently prefer to use the pure carbide; and thepure monoxide as 'starting materials for making] the desired'raction mixture, the carbide and the monoxidef may be lsomewhat impure'without impairing vthe effective? p ness of the process constituting my invention. Thus the carbide may contain some titaniumoxide and the mon? oxdemay contain-someresidual carbon or titaniu'mcar? bide. v
I have now found thatftitanium carbide and titanium monoxide maybe reacted' with one another to produce a" product containing any desired titaniumcontent together, with small yamounts of carbon and oxygen., Essentially my 'method comprises melting titanium'monoxide l iO)A in a vacuum or partial vacuum and adding to the melt contr'polled amounts, offtitanium carbide, .(TC); v maintaining the temperatureabove the liquidus for the system Ii-TiO'-TiC; and by removing carbon monoxide as rapidly as it is formed, a productvv enriched in titanium and impoverished in both carbon and oxygen may be obmovingthe carbon vrnonxide'a" taining=`in excess of 90% titan'i *maybevv obtained' from A'Iielectrode o ffTiOfis sinti'ilarlyipreparediat' ai tempera-j ture of 170()`Q Ci `An are l is fstruck between an, electrode o'ftitani'um ca rbideand van electrode ofV titanium monoxide Vpartial-vaeuurn'aniilqthe molten'drippings are co1- 16C-e active' vacuum pumping.
a second embodimentypelletsmay be prepared from a mixture vfo'tf'titanium Cbide'andjitanium monoxide proportioned lso astoproduce the desired' final Ti-O C composition. TheHpellets may then he fedinto the hr'th of va Vv"va 1ter 'cooled tungstenarc, water-cooledcopper hearth'arcmeltingfurnace and melted vthereon under an A"actively/5purfnpecl lvacuumlto remove carbon monoxide gas genera-ted during the process. f
` As a further alternative, consumable electrodes maybe aro-melted v`toi produce the desired' alloy.' Vrl`hus la powde rjed lt'ure'of titanium `carbideandititanium `monoxide proporti nedfas'above'tmay be moiste'n'edwith methylated spiritsfand rthen" pressed 'or extrudedf'intothe form of pencils suitable for use las electrodes and then baked or paIrtially sintered. The. rods" so .obtained have'an ex# cel odes in an 'arc-melting furnace from which carbon xide may' be remOVedcQntinuQuSIy, jasv rapidly as itis-evolved.yl t' llljhernoyelvtitanium, carbon and oxygen products of this invention fare readily formed bybringingftogether attemperaties above the melting point o fTiO '(l750 C;)`pure titanium l' carbide t and'pure v titaiiilimV monoxide `in suitable propoltionsyconsistent.withjthetemperature and pressure of ,operation toi yield f the'describedjalpha "titanium alloy with oxygen -and carbon Containing a. Asmall amount of a be bound by 'any yspecific theory as to 1Vwhat occurs,l one possible'explauation forthe 'reaction may be offered bashed ontliegaccompapyingjgure representing'the. phase TiO"-TiC,'and'the meltingfpoints for the ternary/'system TTOz-C represented..asTfTOfTiC.
S r'tiu'g with, amixturetotIiOland TiC in e quimo1ar as jshowfn byfthe liquidu's'linefoffthe'TiO-TiC .binaryton between TiO and TiC'a'n'd iv tita' u r n corner.oiltle.ternaryldiagram shownin the gj A s the composition isy progressivelyfdepleted in carboi/1311.@ Q?iygnfaud brrespondingly enriched in titanium,
n the'tern'ary plot. "When suticient lcarbon monoxideA h ajs been removed, `the oxygen content ofthe ksystem is ylfvered tosuch'a'n extent that the over-all composi-t tionfallswithin thealpha regionofthe Ti-HTiO binary. lfeqllilibfum at this time are. (1) alpha titanium, 'sat 'ng'point radually follows the liquidussurfacesJ pumping permits the oxygen contenttobeffurtherl Alo"\1v ered to a valueldeterniin'ed bythe te'I Iipeature,pressure v andcarbon content. i' 'i Event gen as one phase and gamma I`iO,Cy as a second phase. In the specicinstancevcited, i.- e.; ystarting with a molcmol mixture of TiO and TiC analyzing 12.9% O, 9.7% C and 77.4% Ti (all weight percents), I have obtained an alloy analyzing 5.2% O, 5.5% C and 89.1% Ti by weight. From the gure this would represent an alloy of alpha titanium saturated with respect to oxygen and carbon whose total weight is equal to 97.7%.v o f the composition, the remaining 2.3% being free titanium carbide.
in general, the products obtainable by my process have been found, by analysisto'contain from-89% to 92% titanium,' from 2.5%' to 5.5 carbon, and fr om'l.5% to 5% oxygen, depending on the temperature at which the molten. mass .was l1'eld, the proportionsofTiO and TiC employed, the degree of, vacuum, and the length of time the molten mass was held at temperature.
The following additional examples will serve to further illustrate my invention;l
Example l Titanium earb ide of -325 mesh particle `size Iyler standard)` "analysing178.l%`Ti and21.7'%`fC,- and TiO meislifrpar'ticle"size (Tyler'standard) analysing 73.3% titanium, 22% carbonand`24.0% oxygen, were blendedin'equimblar proportions, based on stoichiometric combination of avai lable carbonandoxygen The mixturefwaspressedinto a'ZO gram pellet at 20, tons per square v inchfvvitlaotfit the use of a binder.
1l`he`pellet was fused inlthe, electric arc in an atmosphere of 15 inc hSL(flier-cury)f off.fg0nf R.eaction Wascontinued uritilj'iumin'g 4st c'spped and thechargehad coalesced intoa rOnndbuttm1 Thelbutton, when cooled,.wa s silvery in color. Chemical analysis'indicatediit'anium a'ndf carbon content of 89.5% l and ,5.9% respectively. `Vacuum fusion analysis indicatedan oxyge content of 14.4%.`
Example II Titanium carbd.,of.-'325 .meshparticle size (Tyler standid )gainalysingi,78l,%[titanium Y and y21.7% carbon, and titanium'mo-nbxide of 4325 mesh-particle size (Tyler standard) analysing 73.3% titanium, 2.2% carbon, and 24.0%Uox'7 Yin; Wereblendedin a proportion calculated. toptoyidegangexcess of? 1.5Weightg percent carbon over the, amount o fcarbon required-to combine stoichiometrically wilrhflfhepx'ysea.
The-m terial .was .pelle ted and fused as `in the preceding ,example :"Chernieal analysisjndicated titanium and carbon tcorltelrltsof lF) 1.6%. and 4.7 respectively. Vacuum fusion analysis indicated an oxygen content of 3.4%.
The zh ighg titanium; alloysoi this, invention containing oxygefiie. .reen eredistieguished frOmfOther. prior` art. titan Infoxygenfcarbon compounds fby their extremely 'high anum @erneut example, .Knzie and .Hoke inQ U. -S., Pa tent 204Q,854eported a product correspond-v ing to the formula Ti2OC2 with a titaniumycontent' b..- tweentejfzg; and .69 whilean U,s. Patent 2,129,161,
Ki 'e ra d .fVi/aindescribea substance containing about 65.5 T1-corresponding to -'l i3QC3. Y Other, substances cathode. Where i ifi-eerie@- 5 and claimed in my copending application Serial No. 320,113 which issued on November l, 1955 as Patent 2,722,509. As another alternative, the titanium-oxygencarbon product of my invention may be added to a fused suggest themselves to those skilled in the art, it being obvious that the product of this invention may be used as a starting material for the preparation of titanium compounds as well as for the electrolytic recovery of titanium.
1. As an improved cell feed material for the electrolytic recovery of titanium, a composition of matter in which the titanium content is greater than 89% by weight and comprising two phases: a rst phase constituting the major portion of the composition and consisting of alpha titanium containing an amount of carbon and oxygen corresponding to an amount suii'lcient to saturate titanium present in the liquid state while the improved cell feed 0 material is being produced from titanium monoxide and titanium carbide in a process in which at least one of said starting materials is present in the molten state and containing small amounts of titanium carbide as a second phase; in a relative proportion insufficient to lower the titanium content of the two phases to below 89% titanium by weight.
2. As an improved cell feed material for the electrolytic recovery of titanium, a composition of matter in which the ltitanium content is between 89% by weight and 92% by weight, the carbon content is between 2.5% and 5.5% by weight and the oxygen content is between 1.5% and 5% by weight, which combination comprises two phases: a small amount of titanium carbide as a second phase in a matrix of alpha titanium saturated with carbon and oxygen.
References Cited in the le of this patent UNITED STATES PATENTS Balke June 25, 1940 2,487,214 Berr Nov. 8, 1,949 2,661,286 Swazy et a1 Dec. 1, 1953 2,722,509 Wainer Nov. 1, 1955