US2452139A

US2452139A - Method of preparing uranium deuteride

Info

Publication number: US2452139A
Application number: US546179A
Authority: US
Inventors: Amos S Newton
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-07-22
Filing date: 1944-07-22
Publication date: 1948-10-26
Anticipated expiration: 1965-10-26

Description

Oct. 26, 1948.

A. S. NEWTON METHOD OF PREPARING URANIUM ISEUTERIDE I Filed July 22, 1944 Patented Oct. 26, 1948 METHOD OF PREPARING URANIUM DEUTERIDE Amos S. Newton,

United States of Ames, Iowa, assignor to the America as represented by the United States Atomic Energy Commission Application July 22, 1944, Serial No. 546,179

7 Claims.

This invention relates to the production of compositions consisting of or comprising uranium deuteride and is particularly related to production of uranium deuteride in a highly purified state.

In accordance with the present invention, I have provided uranium deuteride substantially free from other impurities or in a concentrated state as a uranium hydride-deuteride composition in which the hydrogen content is preponderantly heavy hydrogen and preferabl in which at least 90 per cent of the hydrogen is heavyhydrogen. The production of the deuteride is secured by re action of deuterium with metallic uranium and must be conducted under conditions such that little or no deuterium is lost. It has been found that this may be effectively performed in a closed system in which deuterium oxide is introduced, and deuterium is generated from the deuterium oxide and directly used in the system to form the uranium deuteride. The process may be performed in a manner such that completion of the reaction may be automatically indicated as more fully described hereinafter.

Difiiculty is frequentl encountered in effecting the reaction of deuterium with certain forms of uranium. Thus, when uranium powder is used the reaction is often difficult to control and may even occur with explosive violence. On the other hand when sintered uranium powder is used the uranium deuteride forms as a coating and the reaction ceases until the deuteride has been removed to expose a fresh uranium surface. In accordance with the present invention it has been found that many of the difiiculties may be avoided by use of massive or dense uranium metal which is free or substantially free from oxide parting planes in the interior of the uranium mass. When such uranium is used, uranium deuteride is formed in a pulverulent state and crumbles and falls from the uranium body thereby continuously exposing freshuranium to the deuterium. The reaction proceeds so long as metallic uranium is present and the temperature of reaction is maintained.

The metallic uranium used in accordance with this invention may be of high purity or may be mixed, contaminated or alloyed with other materials including tin, copper, bismuth, gold, silver or other metal. The uranium may be alloyed with these metals or merely physically mixed therewith. Moreover the uranium may contain other substances so long as it is substantiall free from internal oxide parting planes. Such uranium or at least the uranium content of ura- 2 nium mixtures has a melting point not in excess of about 1200 C. and in consequence has a density of above 18 grams per cubic centimeter.

Oxide free uranium in massive state suitable for use as herein contemplated ma be prepared by reduction of metallic uranium under conditions such that the uranium becomes molten and drains or stratifies to form a molten pool of uranium from which the impurities separate as a slag layer. Upon solidification of the pool the uranium secured is dense and essentially massive. For example uranium tetrafluoride or similar halide may be reacted with an alkaline earth metal such as magnesium or calcium with consequent formation of an alkaline earth fluoride and uranium metal at a temperature sufiiciently high to melt the uranium and cause it to separate from the fluoride into a molten uranium pool. Alloys or mixtures of this uranium with other metals, particularly those'in which the uranium is the prepoderant component may be treated as herein contemplated.

The foregoing constitute the principal objects of the invention and Will be more fully understood by reference to the specification and the accomanying drawing which is a diagrammatic sectional view of apparatus for carrying out the process.

The uranium deuteride produced in accordance with the invention can be considered to be an intermetallic compound between uranium and deuterium having the approximate composition UDs. Analyses made on the basis of weight gain upon formation of the compound indicate a slightly varying deuterium content depending upon the manner in which the uranium deuteride is treated. Adsorption of the deuterium by the uranium deuteride tends to increase the deuterium content of the compound.

Broadly, the process embodying the invention comprises forming uranium deuteride by bringing deuterium in gaseous form into contact with massive uranium essentiall free from internal oxide parting planes at temperatures sufiiciently high to provide a reasonably rapid rate of reaction of the deuterium and uranium. Preferably the process includes preparing deuterium in gaseous form, as by the reduction of deuterium oxide, and then reacting such deuterium with uranium at elevated temperatures toform uranium deuteride, the reactions being carried out in a closed system.

The drawing illustrates one example of a suitable apparatus I, for providing a closed system wherein gaseous deuterium is prepared and reacted with uranium. This apparatus includes a container for deuterium oxide such as receptacle 2 containing deuterium oxide 3 in an amount suificient to yield, by reduction of the deuterium oxide, the quantity of deuterium in gaseous form required for the formation of uranium deuteride by the subsequent reaction of the deuterium and uranium. To increase the vaporization of deuterium oxide 3 over that obtained at room temperature, Water bath 4 is provided. Water bath 4, heated by conventional heating means, not shown, raises the temperature of the deuterium oxide 3 above room temperature, as for example, to a temperature of approximately 30 C. The deuterium oxide in the form of vapor admitted from receptacle 2 to the closed system i through .stopcock 6.

For passage of the deuterium oxide vapor, tube '1 extends from receptacle 2 into reduction chamber B which is of sufficient size to containa reducing agent 9. The reducin agent 9 may be iron, :zinc, or other material which will combine with (the oxygen of the,oleuterium oxide te ror-m an oxide of -tl'le reducingiagent 9 andrelease the deuterium in gaseous form. Metallic uranium has been found tor-beparticularly suitable for this pwpose as it is highly reactive avith deuterium oX-ide vapor and causes a substantially complete reduction thereof. The reducing agent 9 is preferablyin a 'form such as toiiaverexposed a large surface area, as in the :form of .turnings 'or the like, .and {is so arranged in reduction chamber .8

as to readily contact the .deuterium oxide vapor coming from. tube J. Where metallic. uranium is used as .a reducing agent, stable formation of uranium deuteride in the reduction chamber 8 is prevented by maintaining the uranium at a high temperature.

, flhe reduction @chamber 8 is surrounded by heating means "M which, for example, {may be of conventicnalelectric .ru r nace construction and in the simplest dorm :maycornprise turn-ace casing l2 containing electric heating elements 1-3. Heating :means All is adapted to -maintain reduction ohambeiufi at a suitable temperature sufiicientlt high to cause the iron or' otherqmetal torreact with the deuteriurnwoxide to form deuterium, suehas, ior example, at 2a temperature between 600 QC. and 800 C., for the reduction of the deuterium oxide vapor by reducing agent 9. Heat ng means all includes suitable control means, not shown,

.fcr maintaining med-notion [chamber :8 at the desired temperatures.

The gaseous deuterium resultin ,zfrom zthereduction of the .deuteriumpxide :is conveyed from .re,duction--.c-hamber -8-into trap 46 :by tube [4 which extends into the trap. The trap 1 I 6:1'emoves unred-.uced deuterium oxide vapor -.carried by the gasleous deuterium, the purification being eiiected by maintaining the trap at lowtemperatures, thereby causing condensation of any deuterium oxide --vapor present. Trap L6 is cooled by suitabletcool- .ing means such asgfor example, solid carbon 1dioxide H and acetone :IB contained receptacle 415. purified deuterium is conveyed .trom trap I16 into reaction achamberlz through tube its-and stopcock 2-! Where it is :found desirable to effect the :prepla-rationof uranium deuteride :by :the reaction 'of previously prepared deuterium and uranium meta'l'or tosupplement deuteriumpreparedin chainber-fl -supply tube 3-! maybe provided for introducing previously prepared gaseous deuterium friom a source of gaseous deuterium, 'not shown, through tube 4:9 and into reaction chamber 2-2. :Supplytube ,3 I may be opened-and .closedby topcock 32. If the process comprises preparing gaseous deuterium and reacting such deuterium with uranium in the closed system I, stopcock 32 is closed, thereby shutting ofi supply tube 3|. If the process includes reacting previously prepared deuterium with uranium in reaction chamber 22, stopcock-2| may the closed tiQShutlOfi :supply tube lELand stopcock Z32 is opened, thereby :admitting previously prepared deuterium to reaction chamber 22 or deuterium may be supplied from both sources.

Reaction chamber 22 contains metallic uranium 23 in massive or dense state and free from internal oxide parting :planes with which the gaseous deuterium reacts to form uranium deuteride.

' Preferably, the uranium metal 23 is in a form presenting .a large surface area, as in the form of turnings or the like. The reaction chamber 22 .is surrounded by heating means 24 such as a conventional electric furnace comprising casing .28 containing electric heating elements 2 Heatin means-24 is adapted to maintain reaction chamberiZZ at .a suitable temperature, such as, for example, between 15.0" C.-and 400 C, forlcausing a reasonably rapid rate of reaction between the gaseous deuterium and :the metallic uranium. Heating means 24 includes suitable and conventional control means for ,-maintaining .reaction chamber 22 at the desired temperature.

As it is desirable to .remove residual atmospheric oxygen from the system before carrying out theiprocess, reaction chamber 22 isprovided with outlet tube 2:8 which is "connected to .a conventional type of mechanical exhaust means, not shown, capable of obtaining a vacuum in the system of the order of .l millimeter mercury pressure and the system isevacuated whilestopcock =9 is closed. After evacuation-stopcock 29 is closed thereby closing the entire system.

, The various elementsof :the apparatus are 1 suitably formed of a .material, such as :heat resistant glass, stainless steel, ,glass lined iron, etc., that withstands .elevatedtemperatures, resists corrosion, and does not contaminate-orzreact with the substances presentin the. system. Manometer 33 "or equivalent pressure indicating .means may be connectedto the system on an extension .of tube 1 .to indicate visually the pressures developed during theprocess.

Where it is desiredlto obtain uranium deuteride by a process in which previously prepared-deuterium .is reacted with uranium to form uranium :deuteride, stopcock -2-l is-cIOsedthe-reby shutting off reaction chamber 22 from the remainder -of the system, and previously prepared deuterium ispadmitted under pressurefrom a deuterium sup- ;ply chamber, notshown, .to reaction chamber '22 through supply tube 31 by opening stopcock 32.

,Reaction chamber l-z containing massive uranimetal in the .form of turnings or other convenient form presenting a ,large surface "area is heated byifurnace 24 to a favorable temperature .for. the reaction between :the uranium and deuterium, as, for example, between 200 .C. and 400 C. In general, the reaction ,proceeds more rapidly as the temperatureand pressure of reaction chamber .22 is increased, the pressure of reaction chamber 22 being automatically controlled by the rate of generationof the deuterium-in the closed system.

In carrying out the process in which .zgaseous deuterium is prepared in the system .and then reacted withuranium, stopcock '6 'is closed,wsto.pcocks 12.1 and, (29 are opened, and the system .is evacuated through-exhaust tubal-8. vAfter asufat a suitable temperature, such as between 600 C..

and 800 0., for the reduction of the deuteride oxide vapor. The gaseous deuterium resulting from the reduction of the deuterium oxide in the reduction chamber passes through tube l4 into the-trap in which deuterium oxide vapor carried by the deuterium is condensed and removed. ,,The dried deuterium is conveyed by tube [9 from the trap into reaction chamber 22, maintained at a suitable temperature by furnace 24, in which the deuterium reacts with metallic uranium 23. to form uranium deuteride. Reaction chamber 22 is preferably maintained at a temperature similar to that maintained in reaction chamber 22 when previously prepared deuterium is reacted with uranium, such temperature being, for example, between 150 C. and 400 C. As the reaction takes place, the uranium deuteride tends to fall away from the uranium metal thereby exposing additional. uranium metal for further reaction. The reaction continues until all of the uranium is converted to uranium deuteride. At a temperature of 300 C. in reaction chamber 22, 100 grams. of uranium turnings have been converted -to uranium deuteride in less than thirty minutes and a 100 gram lump of uranium metal has been converted to uranium deuteride in less than two hours.

After conversion of the uranium metal to uranium deuteride is substantially completed, the pressure in the system increases rapidly as the supply of deuterium to the system continues, such increased pressure in the system being visibly indicated by manometer 33. stopcock 2| is then closed to seal oif reaction chamber'ZZ from the remainder of the system and to permit removal of the uranium deuteride. Stopcock 6 is also closed to prevent further generation of deuterium in reduction chamber 8. The uranium deuteride is preferably partially cooled in the atmosphere of ga'seous deuterium present in reaction chamber 22 in order to prevent orminimize thermal decomposition of the deuteride at the end of the reaction. Where stopcock 2| is not provided, reduction chamber 8 should be maintained at a lower temperature than that of reaction chamber 22 during the cooling of the uranium deuteride to prevent distillation of deuterium from reaction chamber 22 to'reduction chamber 8 and the consequent decomposition of the uranium deuteride during cooling.

The pressure established in reaction chamber 22 during hydrogenation and cooling is maintained at or somewhat above the decomposition pressure of the uranium deuteride. Thus where a temperature of approximately 300 C. is maintained in the reaction chamber, the decomposition pressure of the uranium deuteride is approximately 27 millimeters and the uranium deuteride formed will decompose at this temperature into deuterium and uranium metal whenever the deuterium pressure falls below this value. Continued introduction of deuterium into the reaction chamber tends to" increase the pressure until it exceeds the decomposition pressure, thereby causing formation of uranium deuteride. As the deuterium combines with the uranium, the pressure in the reaction chamber tends to decrease and if the pressure goes below the her increases the proceeds.

This afiords a simple and efiective means forcontrolling the r-ate of deuteride formation and for determining the time at which the reaction iscom-pleted. Thus,

cess of the decomposition pressure but insufilc1en=t to cause the hydrogenation-reaction to"oc'-- our more or less explosively. Usually a pressure which is not over the decomposition pressure is established. In

general deuterium is introduced substantially as and at a rate sufiiclent rapidly as it is consumed to replace consumed hydrogen and to maintain thedeuterium pressure peratur-e.

After the reaction has been completed, thedeuterium introduced causes the pressure-to"-in- Ewample 2016 grams of powdered uranium tetrafluoride having a particle size such that per centpasses a 60 mesh screen, 85 per cent passes an 80 mesh screen and 50 per cent passes a 200 mesh 7 was mixed with 400 grams of metallic magnesium having a particle size of about 20 mesh, the charge packed in an iron crucible lined with calcium oxide and the crucible closed. The crucible was gradually heated until it reached an outside ternperature of about 640 C. Molten metallic ura-" nium and magnesium fluoride formed anduthe temperature of the mixture was maintained sufficiently high to retain theuran'ium in molten state until the uranium and the magnesiumjffiuoride separated into separate layers wherebyupon cooling massive uranium having a melting point of 1100 C.25 and a density of 19-01 grams per cubic centimeter was secured.

This uranium was formed into turnings and was placed in reaction chamber 2 2 1,00fgra ms of uranium metal, also in thef-orm of turning's, were placed in reaction chamber 8. Flask 3 was partially filled with deuterium oxide concentrate} containing 99' per cent by weight of D 'Qfand; water bath 4 heated to approximately 30 CfRe ceptacle l5 Was filled with dry ice and acetone. With stopcock 6 closed and stopcocks 2| and 25 decomposition pressure. the formation of uranium deuteride is retarded until" further supply of deuterium to the reaction sham-1 pressure above the decomposi= tion pressure whereupon deuteride formation:

at the start of the reaction:- deuter-ium is supplied to chamber 22 in an amount: sufficient to establish a deuterium pressure in ex about millimeters 1 "above within the system -.-above. the decomposition pressure at the reaction'tem-f pressure increase will be:

it is necessary to pre pare the deuteride from a composition in which screen o en, an vac-um. of: the atria of, .r millimeter: wastobtained; the system by; evacuating means attacheditn ontlettuhez Zll .v stopcock; 28: was then; closed;.. reaction chamber? 8:. heated to. approxis- 700 G2; and: reaction: chamhenrm. heated; to approximately 250 C. by furnace 24.. There;- coclc &- was. opened: and. deuterium oxide vapor: delivered to chamber 8 ion deuterium. formation; and; the process conducted. as. previouslydescribed. The conversions oi' uraniumto urae niumdeuterlde waszsubstanti ally complete inz-two and aha'lfihoursathe completion; being indicated by: manometer-""33; stopcock was closed, the apparatuscooledzand disassembled, and. the uraniumadeuteride in the; amount. of. 102.54 grams. WEIS-"IQmDYBd.

Uranium; deuteride is. a black; powder which has been: found to he a; convenient means of storing or handlingdeuterium. in a form: from. Whiflhl the deuterium canbe made readily.- availahle;-as;a. pure gas. One gram mole of. uranium deuteride oia bulk densityfromv 35130, 4; that is, 60 to 80 cubic centimeters of the compound conztains approximately 35- liters, of deuterium at atmospheric; pressure; Deuterium in. gaseous form: is released: from; the: uraniumdeuteride by heating the; compound above its decomposition temperatureatathe existing pressure.

The approximatedecomposition temperature of the: uranlmndeuteride at various pressures, in millimeters; of mercury is given in the following tablet.

Uranium Uranium Deuteride Hydride Decomposition Decomposition Pressure Pressure mm; of Hg' m-n1 of g.

The term uranium as used in the following claims is intended to include metallic uranium, physical mixtures. of uranium with other materi-alssuch as. tin or other metallic. dendrites, and alloys in which uranium is the predominantconstituent...

The above detailed description is for purposes of; illustrationand the invention is to.-be limited only by. thescope. of the-following. claims.

Eris-application is generally related to my copending applicatiomserial No. 546,178, filed July 22, 1344-,- now Patent No. 2,446,780 dated-August 10; 1948, which. is directed to aprocess of preparinguranium hydride.

What is.claimediis:

LThe process of preparing uranium deuter me. which. comprises reducing. deuterium oxide in a closed. system tov obtain. gaseous deuterium and then reacting the deuterium with uranium insaid system. I

2. Theprocess of preparing uranium. deuteride which comprises passing deuterium. oxide. vapor overa reducing agent in afirstreactionzone to obtain gaseous deuterium. and then. passing the generated deuterium over uranium ina second reaction zone Whichis in. intercommunication with. thefirst' reaction zone.

3. Thevprocess of: preparing uraniunrdeuteridw which. comprises. introducing. a composition in" which. the preponderant aqueous. compound: is

deuteriumzoxide. into a closedsystem generating deuterium oxidevapor at a. constant rate in said deuterium oxide vapor and a reducing agent inra firstreaction zone in sald system: at. atemperature sufficient to reduce the deuterium oxide vapor to gaseous deuterium;

system, reacting said and thenreacting the deuterium ith uranium im another? reactionxzone in said system at'. a temperature between C. .andAOflf" C;

4.-.. The process of preparing: uranium deuteride which comprisesv introducing a:. composition inwhich; thev preponiderant aqueous compound is deuterium oxidein-tow a closed: system generat ing deuterium: oxide vapor at: a. constant rate-1m said system, reacting-said deuterium oxide-yawn: anda reducing agent. in a first. reactionazone atsa temperature sufficient. to reduce the deuteriumi oxide vapor to'gaseous' deuterium, dehumidifying: the. deuterium. and; then, reacting: the. deutenium with-uranium in saidsystem.

5. The process of obtaining. uranium. deuterid'e. which comprises introducing deuterium; oxide in a closed system generatingdeuterium oxide vapor at a constant rate in saidsystem, reducingsaim deuterium oxide vaporto'gaseous; deuterium at' ai constant rate and passing the gaseous deuterium into contact with uranium at" a temperature-he tween 150 C. and 400 C. in saidssystem..

6. The process of preparing uranium deuteride" which comprises generating. gaseous deutertumnim aclosed system, reacting-the deuterium substan.-- tially as rapidly as formed with uranium in said system, and visually indicating the: gaszpressure within the; system whereby an increase in said: pressure indicates the completion. of the reaction: betweenth'e deuterium and the uranium;

'Z. A. method of preparing uraniun'r deuteridewhich comprises introducing: a. composition. in: which. thepreponderant. liquid aqueous; compo?- nentv is deuterium oxide intoa CIOSGdiSYStEIIlLhK-Yr ing. three zones communicating in; series, introe ducing a reducing metal into the second; zone and uraniumv metal. into the third zone,..heatinzi the deuterium oxide whereby deuteriumoxide: Val por is.generated and. forced into-the second: zone; heating. the. second zone tocause: interactionaofl the reducing metal. with thevapor and generate: deuterium gas which is torced bythe incoming vapor into the. third zone and heatingthe'thirrh zone toreact the deuteriumwith the uranium..

AMOS S. NEWTQN.

REEEBENCESv CITED.

The following: references. are of; record in the file of this patent:

UNITED; STATES PATENTS.

Number Name Date- 1,816,830 Driggs Aug. 4,1931"- 1,835,024- Driggs Dec. 8; 1931 2,156,851-

Hansgirg. May 2, 1939 OTHER REFERENCES Certificate of Correction Patent No. 2,452,139. October 26, 1948.

AMOS S. NEWTON It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 66, for 1100 C.25 and a density of 19-0.1 grams read 1100 C'.i25 and a density of 19:1;01 grams,

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofice.

Signed and sealed this 5th day of July, A. D. 1949.

THOMAS F. MURPHY,

Assistant Uommz'ssioner of Patents.

I Certificate of Correction Patent No. 2,452,139.

AMOS S. NEWTON It is hereby certified that error a ppears in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 66, for 1100 C.-25 and a density of 190.1 grams read 1100 0.:b25 and a density of 1-9;l;0.1 grams;

THOMAS F. MURPHY,

Assistant G'ommieaz'oner of Patents.

October 26, 1948.