US1202534A - Production of metallic tungsten. - Google Patents

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F. G. KEYES & R. B. BROWNLEE. PRODUCTION OF METALLIC TUNGSTEN.

APPLICATION FILED JULY 5- 1914.

Patented Oct. 24, 1916.

ATTORNEY UNITED STATES PATENT OFFICE- FREDERICK G. KEYES AND ROBERT B. BROWNLEE, OF EAST ORANGE, NEW JER EY,

ASSIGNORS TO COOPER HEWITT ELECTRIC COMPANY, OF HOBOKEN, NEW Il'ERSEY, A CORPORATION OF NEW JERSEY.

PRODUCTION OF METALLIC TUNGSTEN.

1,202,534. Specification of Letter-S Yatent- Patented Oct. 24, 1916.

Application filed July 6, 1914. Serial No. 849,137. To all whom it may concern: actor of the deposit desired, the dimensions Be it known that we, FREDERICK G. KEYES of the bath, the volume of the electrolyzing and Roman? B. Bnowunuu, citizens of the fluid, and the area of the-electrodes. The

United States, and residents of East Orange, crucible itself should be of tungsten or high 55 5. county of Essex, St. te of New Jersey, have melting alloy of tungsten that 15, it should invented certain new and useful Tmprovebe of such a character as not to contaminate ments in the Production of Metallic Tungthe bath with impurities if it is desired to sten, of which the following is a specificaproduce pure tungsten. I however, it be desired to produce, for example. a car on- 60 tion.

The attempt to produce metallic tungsten bearing deposit, the crucible material may by electrolytic processes has hitherto shown contain. carbon.

very meager results. It has been found, for In order to bring the electrolytic subexample, that it is impossible to obtain stance into a fluid condition, and to maintungsten electrolytically from an aqueous tain it in such condition during the electro- 65 solution of its salts. It has also been found lyzing process, use is made of the fact that that only the so-called tungsten-bronzes can the substance conducts electricity when col be obtained from molten para-tungstates. and may consequently carry current enough Moreover,- while we have found that tungto bring it to a fluid condition through the sten tri-oxld gives a clear solution in bone action of the PR heat or Joule heat. As- 70 acid at 1.000 to 1200 degrees centigrade, even sunung that the lower oxid formed b the with a high concentration of the tri-oxid, initial igntion above referred to isW ,we yet such a solution submitted to a tension know that the heat of formation of this oxid of from 110 to 500 volts at temperatures is 131,000 calories per gram molecule; hence,

from 1000 to 1300 degrees centigrade perabout one volt is the decomposition or depo- 75 units only a fraction of an ampere to pass. sition potential. Suflicient energy m add1- Separation of tungsten took place when the tion to this must be applied to maintain the electrolytic action was prolonged, but the mater al in a fluid condition. process was necessarily slow and, for that Recapitulating the foregoing description reason, was temporarily cast aside. Similar of the novel process herem described, the 80 results were obtained with a solution of steps conslst, first, of a. more or less protungsten oxy-chlorid in fused boric acid. "A longed ignitionof W0 at 1800 to 2000 depractical process'of producing metallic tunggrees centigrade. This results in the bsten is found, .however, by igniting for a eration of a portion of the oxygen, leaving more or less prolon ed period WO at 1800 a lower oxygen compound or a mixture of 85 to 2000 degrees C. Under these conditions such oxygen compounds. Thus, the first the liberation of oxygen takes place, resultstep in the process may leave or ing in the formation of lower oxids of tungor a mixture of these two oxids. The substen and the production of a dark blue crysstance resulting from this part of the proctalline substance which conducts electricity ess is then brought to a fluid state and mam- 90 readily at ordinary temperatures. The subtained in said state, preferably by means 0 stance is fluid at about 2000 degrees centithe PR heat, and a surplus of energy is apgrade and in its fluid condition mav be'utiplied to the material for maintaining it in a lived as an electrolytic bath from which mefluid condition. The application of electric tallic tungsten can be separated'by the obcurrent to this fluid material causes a com- 95 servance of a proper mode of procedure. pact deposit of metallic tungsten upon the In general we prefer to employ a rotatcathode. As already stated, the cathode is ing cathode of tungsten and an anode in the of tungsten, and preferably a rotating cathform of a sintered rod of-tungsten, through ode, while the anode 1s, for example, a tungwhich and through the oxid bath an electric sten anode consisting of a sintered rod of 10 current is passed. Varying current 'densltungsten. The density of the current apties may be employed according to the charplied to the bath'varies according to conditions already stated. It has been found that swa ed down to a diameter where it is pracat high temperatures anodes of high melting tica to reduce the diameter still further by metals, as iridium, become oxid1zed at the drawing dies.

anode in this bath since oxygenis liberated, Plalnly, the process described herein may and that, moreover, such oxid passing into be utilized for re ng. a metal or for ohthe solution, the metal ion is deposited upon taming a metal from its soluble salts. There the Cathode, thereby producing an a1loy,or Is no istlnctlon, so far as the naturepfthe at any rate, contaminating the deposit" of process goes. The case of tungsten, 1f that pure tungsten which it is desired to obtain. be the metal'sought to be thrown down by 1 course, an ideal electrode would consist t e present process, is completely analogous f a ast bar of lower tungsten oxids since to the well-known copper process, wherein an anode bar. Obviously, such an anode or, rloxld may e utillzed as anodes.

they conduct the electric current with facopper is obtained from its soluble salts by cility. Asa matter of course, the melting usmg a magnetic anode or a platinum anode point of such an oxid would be the same as in a splutionpf copper or wherein an electhe bath in which the electrolysis is being trolytlc refining of copper 1s obtained by 8 carried out and hence the use of such an means of an impure copper bar used as an anode is precluded. The melting point of anode.

the anode, however, may be adjusted by mixv For certam p rpose 1t is desirable to obing thelower tungsten oxid and tungsten tain very pure tungsten and to this end bars powder and casting this into the form of pressed up from partially reduced tungsticat least the particlesof tun ten co osing obvious. that a pressed bar, even of pure it, will be attacked by th anion, the metal, would not be homogeneous, whereas present instance oxygen, forming oxid in an electrolytically disposed metal would of deposit desired.

' posit of considerable thickness of metallic all probability and'thereby, becoming a pornecessity be homogeneous. "I would be postion of the bath itself. Thiszis desirable ,sible to use a pressed bar of O which has and forms as will be readily perceived, a a sufficiently 'gh melting point but it is means of renewing the electrolytic bath.- more convenient to reduce tungsten trioxid her anodes, of course, may be. used deto the point where it contains enou h lower pending upon the character of the cathode oxid to increase the melting point a vs the temperature at which it is to be used asan I t is convenient to use as the cathode a anode. Usually, intbis case, a small amount tungsten w re about one-Sixteenth of an inch of metal will be present in the resulting in diameter. The first .Wire' -used in the powder. It is, of course, possible to reduce. formatlon of subsequent 11 wires may 11 with carbo in the electric furnace, of iridium, 'for example, and after a deand res and sinter this material intobars t h be f d1 .will serve 21s anodes. ailiyelec ungsten as en orme upon this iri "um tro ytic' proces or eve' e uiva cut .0 wire the ngot thus created may be swaged el ctrochemical material dgosi ed upon thedown and a art of the wire again cathode, the same electrochemical equivalent 9 asacat ode. By repeatingthisprocess must be taken from the bath or from the ate and a pure anode. tungsten wire to form the cathode is ob- In the foregoing s ification we have tained. stated that it is deslrab e that the cathode be It will be und rstoed'that we have mencaused to rotate. The ob ect of this scarcely 9 t oned the use o fan orlgmal iridium cathode requires explanation, but it will be under- After the iridium has een of rotation will tend to keep the bath in an remov b berapeated operations such as have active condition with. a mare or less free'cirn descn wires or other sha of our gradeor quality of ngste may bf utilized 'We have Illustrated the means for rotatas cathodes. There is, of course, no' conmg thecathode in the accompan g draw-. trolling reason why ordinary commercial ing which is a vertical seeltion o a tubular if fiesimd if'suited tmpeciall n ds or re re located the anode and the cathode of the 'quirements'. When sufiiczent tungsten has syste been deposited upon the cathode, the wire f The furnace itself is shown at 1 and the mayjbe removed and another substituted.- In crucible inside the furnace at 2. Within the practice, to prevent the bath from-coolin it crucible is the electrolytic bath 8 alread is recommended to use two rotating cathodes, described. The crucible is subjected to very one of which may be: removed and a new hightemperature and must be of very recathod'e plaeed 1 n the 'ectrode holder. The iractory material, preferably tungsten. It

el c, with its deposit, 18 then isnot that the crucible bemade of of the transformer,

pure tungsten, although the material employed for the crucible should be such as would not contaminate the bath containe in it. A support 4 sustains the crucible as shown.

The anode of the bath appears at 5, and the cathode at 6. Both are connected by an electric circuit, the opposite terminals 0 which run to a storage battery 7.

It has been stated that it was of advantage to have the cathode rotate during operation. This is accomplished by means of a pulley having a V shaped groove and a hearing, together with an independent operating driving motor. The bearing is shown at 8, the pulley at 9, and the driving motor at 10, the pulley and driving motor being connected by a band 11. Because of the high temperature of the ba h, it is preferable to mount this pulley bearing and the driving mechanism therefor at a point well remove from the surface of the crucible.

As to the details of the furnace, the same is preferably made of graphite and is provided with enlargements l2 and 13, through which connection is made to the terminals either with or without f bands 14 and 15 of metal surrounding the enlargethe intervention 0 or other conductor ments.

The primary of the transformer forming the direct means for energizing the furnace, is shown at 16 and four coils 17 17 arranged in parallel, constitute the secon ary of t e primary 16, and are connected to the furnace at 14 and 15. The drawing shows practically the entire system described herein.

We claim as our invention:

1. The method of producing pure tungsten which consists in bringing an oxi of tunguid condition in an inert environment, maintaining the said condition by Joule heat, and separating the tungsten from the electrolyzing bath by an electrolytic process.

2. The method tungsten sten trioxid to a temperature of approximately N00 degrees centigrade,thereby producinga lower oxid or mixture of oxids conductive of electricity and also thereby bringing the resultant substance to a fluid condition, maintaining such a condition and passing an electric current therethrough.

3. An electrolytic apparatus comprising a bath of fluid oxid of tungsten, a rotating tungsten cathode and a highly refractory anode.

4. In a fused electrolyzing bath, a cathode of pur tungsten and an anode consisting of a sintered rod of pure tungsten.

Signed at New York in the county of New York and State of New York this 3rd day of July, A. D. 1914 FREDERICK G. KEYES. ROBT. B. BROWNLEE.

of separating metallic Witnesses Tnos. W. Bnown.

which consists in subjecting tung-

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