US2855270A - Process of recovering uranium - Google Patents

Description

Oct. 7, 1958 J'. M. CARTER ETAL 2,855,270

PROCESS OF RECOVERING URANIUM 5 Slieets-Sheet 1 Filed Oct. 20, 1944 s W Y T A Nrn R EEO w M Cm. 3 m JC Oct. 7, 1958 3119a Oct. 20. 1944 .1. M. CARTER ETAL PROCESS OF RECOVERING URANIUM 5 Sheets-Sheet 3 DISSOLVING URANIUM' METAL DEPOSITED ON STAINLESS STEEL COLLECTOR IN CONDENSA TE AND MAKE UP (I) HNO; 0!? (2)HC/ 8 H 0 on (3)1450 & H 0

coNoENslN s WA 75/? VAPOR EVAPORATING CONCENTRATED SOLUTION SOLUTION U0 Fe +4-4- c TO FU RTHER TREATMENT INVENTORS James M. Carter BY Clarence E. Larson ATTORNEY.

Oct. 7, 1958 J. M. CARTEIR ETAL PROCESS OF RECOVERING URANIUM Filed 001;. 20, 1944 s Sheets-Sheet 4 STARTING SOLUTION MATERIAL 2 FROM PRIOR 2: 11 TREATMENT F/LTRA TE PRECIPITATIN G ZNH40H AND FILTERING PREC/P/TA 75.5

I (N )z 2 7 FEZOH): 040/1) 22%;- DISSOLVING To DISCARD OR SALVAGE SOLUTION v 0 Fe Cr-f-f-I- //-Fe+++ 5 3% pp,q0x lFFe 3% APPROX.

G COMPLEXIN G LACT/C AC/D Fe +'H" ACET/C ACID FLUOR/DE NULLAPON v ADJ U ST I N G H L0 3.0

"" AND coo LING @515 N, +4- Cr Fe PRECIPITAT IN G 1 ZHZOZ AND FILTERING A T0 DISCARD OR SALVAGE CALCINING PRE C/P/ T A TE U04- GAS TO FU RTH ER TREATMENT INVENTORS James M. Carter Clarence E. Larson ATTORNEY.

Oct.f7, 1958; J. M. CARTER ETAL 2,855,270

' PROCESS OF RECOVERING URANIUM Filed Oct. 20, 1944 5 Sheets-Sheet s STARTIN G MATERIAL FROM PRIOR TREATMENT V v GASES GASES REDUCING QREAC'TING CH4. 32 00 Q Clg a uc/ GASES r REAc-rm coma CALCINING GAS- cm 28 a .Cla

u :/.,l v -u c/ RES/DUE U02 UOC/ SUBLIMING IN 'VACUQM TQ SALVAGE 8UBL/MATE'UC/4 END PRODUCT INVENTORS James M. Carter BY I Clarence E. Larson ATTORNEY.

nited States Patent PROCESS OF RECOVERING URANIUM James M. Carter, Pasadena, Calif., and Clarence E. Larson, Oak Ridge, Tenn., assignors to the United States of America as represented by the United States Atomic Energy Commission Application October 20, 1944, Serial No. 559,624

8 Claims. (Cl. 2314.5)

The present invention relates to processes of producing uranium and more particularly to improvements in certain steps of the process disclosed in the copending application of James M. Carter and Martin D. Kamen, Serial No. 532,159, filed April 21, 1944, now Patent No. 2,758,006.

It is an object of the invention to provide an improved process of reclaiming uranium from a calutron.

Another object of the invention is to provide an improved process of recovering the residue of an uranium compound which has been subjected to treatment in a calutron from the parts of the calutron disposed in the source region thereof upon which the residue is deposited.

Another object of the invention is to provide an improved process of recovering metallic uranium from the collector of a calutron upon which the enriched metallic uranium is deposited.

A further object of the invention is to provide an improved process of purifying uranium which has been recovered from a calutron.

A still further object of the invention is to provide a process of reclaiming uranium from a wash solution derived from a calutron, in which the uranium is precipitated as uranium peroxide away from metal impurities in the wash solution.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings in which Figure 1 is a perspective View, partly broken away, of a calutron in conjunction with which there may be carried out the process of the present invention; Fig. 2 illustrates a portion of the flow diagram of the present process, indicating the recovery of the residue of UCL, from the parts of the calutron disposed in the source region thereof upon which it is deposited; Fig. 3 illustrates another portion of the flow diagram of the present process, indicating the recovery of the metallic uranium from the collector of the calutron upon which it is deposited; Fig. 4 illustrates a further portion of the flow diagram of the present process, indicating the purification of the recovered uranium; and Fig. 5 illustrates a still further portion of the flow diagram of the present process, indicating the ultimate conversion of the purified uranium back to UCl At the outset, it is noted that a calutron is a machine of the character of that disclosed in the copending application of Ernest 0. Lawrence, Serial No. 557,784, filed October 9, 1944, now Patent No. 2,709,222, and is employed to separate the constituent isotopes of an element and more particularly to increase the proportion of a selected isotope in an element containing a plurality of isotopes in order to produce the element enriched with the selected isotope.

Such a calutron essentially comprises means for vaporizing a quantity of material containing an element which is to be enriched with a selected one of its several isotopes; means for subjecting the vapor to, ionization, whereby at least a portion of the vapor is ionized causing ions of the several isotopes of the element to be produced; electrical means for segregating the ions from the un-ionized vapor and for accelerating the segregated ions to relatively high velocities; electromagnetic means for deflecting the ions along curved paths, the radii of curvature of the paths of the ions being proportional to thev square roots of the masses of the ions, whereby the ions are concentrated in accordance with their masses; and.

means for de-ionizing and collecting the ions ofthe selected isotope thus concentrated, thereby to produce a deposit of the element enriched with the selected isotope.

Referring now more particularly to: Fig. 1, there is illustrated a representative example of a calutron. 10 of the character noted, which comprises magnetic field structure including upper and lower pole pieces 11 and 12,, provided with substantially fiat parallel spaced-apart pole faces, and a tank 13 disposed between the Pole facesof the pole pieces 11 and 12. The pole pieces 11- and 12 carry windings, not shown, which are adapted to be energized in order to produce a substantially uniform and relatively strong magnetic field therebetween, which magnetic field passes through the tank 13 and the various parts housed therein. The tank 13 is of tubular configuration, being substantially crescent-shaped in plan, and comprising substantially flat parallel spaced-apart top and bottomwalls 14 and 15, upstanding. curved inner and outer Walls16 and 17, and end Walls 18 and 19. The end Walls 18v and 19 close the. opposite ends of the tubular tank 13 and are adapted to be removably secured in place, whereby the tank 13 is hermetically sealed. Also, vacuumpumping apparatus, not shown, is. associated with the tank 13,,whereby theinteriorof the tank 13 may be evacuated to a pressure of the order of 10- to-10- mm. Hg. Preferably, the component parts of the tank 13 are formed of steel, the bottom wall 15 thereof resting directly upon thepole face of the lower pole piece 12,, and the top wall. 14 thereof. being spaced at suitable distance from the pole face of the upper. pole piece 11, whereby the top and bottom walls. 14- and 15 constitute in effect pole pieces with respect to the interior of the tank 13, as explained more fully hereinafter.

Thev removable end wall 18 carries an insulator 20 which supports an upstanding charge block 21,.provided with a hollow central cavity 22 constituting a charge receiving pocket. surrounded by rather thick side walls. Electrical heating elements 23 are embedded in the side walls of the charge block 21 and are adapted to be connected to a suitable source of current, whereby the charge block 21 may bev appropriately heated, the charge block 21 being formed of cast steel or the like. Also, the charge block 21 is provided with a removable cover, not shown, and supports a tubular member 24 which in turn supports an arc block 25 formed of carbon or graphite.v The are block 25 is substantially C-shaped in plan, an upstanding slot 26 being formed in the wall thereof remote from the charge block 21. Thus, the arc block 25 is of hollow construction, having a central are cavity 27 formed therein, the arc cavity 27 formed in the are block 25 communicating through the tubular member 24 with the cavity 22 formed in the charge block 21.

Also, the removable end wall 18. carries an insulator 28, disposed above the insulator 20, which supports horizontally projecting cathode structure 29, including a filaa mentary cathode 30 adapted to be connected to a suitable source of current. The cathode structure 29 projects over the upper end of the charge block 21, whereby the filamentary cathode 30 overhangs and is aligned with respect to the upper end of the cavity 27 formed in the arc block 25. Further, an anode 31 is arranged below and in alignment. with respect to the lower end of the cavity 27 formed Patented Oct. 7, 1958 in the arc block 25, the anode 31 beingsupported by the charge block 21. The filamentary cathode 30 and the cooperating anode 31 are adapted to be connected to a suitable source of current; j

Ion accelerating structure, including a pair of upstandmgplates 32 formed of carbon or graphite, is supported by insulating structure, not shown, carried by the removable end wall 18. The pair of upstanding plates 32 are arranged in spaced-apart relation in order to define aslit 33 therebetween, arranged in substantial alignment with respect to the slot 26 formed in the wall of the arc block 25. A suitable source of voltage is adapted to be connected between the arc block 25 and the ion accelerat- 1ng structure, including the plates 32, for a purpose more fully explained hereinafter.

The removable end wall 19 carries an insulator 34 which supports an upstanding collector block 35 formed of stainless steel or the like and provided with two laterally spaced-apart cavities or pockets 36 and 37 which communicate with aligned slots 38 and 39 formed in the wall of the collector block 35 disposed remote from the removable end wall 19. Alternatively, the collector block may be fabricated of steel plate and the inner surfaces of the pockets 36 and 37 lined with stainless steel plates. It is noted that the pockets 36 and 37 are adapted to receive two constituent isotopes of an element which have been separated in the calutron 10, as explained more fully hereinafter. Finally, the inner wall 16 carries a number of insulators 40 which support a tubular liner 41 formed of copper or the like, rectangular in vertical cross-section, disposed within thetank 13 and spaced from the walls 14, 15, 16 and 17 thereof. One end of the tubular liner 41 terminates adjacent the accelerating structure, including the plates 32; and the other end of the tubular liner 41 terminates adjacent the collector block 35; the tubular liner 41 constituting an electrostatic shield for the highvelocity ions traversing the curved paths between the slit 33 formed by the plates 32 of the ion accelerating structure and the slots 38 and 39 formed in the collect-or block 35, as explained more fully hereinafter.

In view of the above description, it will be understood that the parts of the calutron 10 carried by the removable end wall 18 constitute a source unit, and the end of the tank 13 disposed adjacent the source unit constitutes the source region of the calutron. Similarly, the parts of the calutron carried by the removable end wall 19 constitute a collector unit, and the end of the tank 13 disposed adjacent the collector unit constitutes the collector region of the calutron.

Considering now the general principle of operation of the calutron 10, a charge comprising a compound of the element to be treated is placed in the charge pocket 22 in the charge block 21, the compound of the element :1 a mentloned being one WhlCh may be readlly vaporized. The cover, not shown, is then secured on the charge block 21 and the end walls 18 and 19 are securely attached to the open ends of the tank 13, whereby the tank 13 is hermetically sealed. The various electrical connections are completed and operation of the vacuum pumping apparatus, not shown, associated with the tank 13 is initiated. When a pressure of the order of 10" to mm. Hg is established within the tank 13, the electric circuits for the windings associated with the pole pieces 11 and 12 are closed and adjusted, whereby a predetermined magnetic field is established therebetween, traversing the tank 13. The electric circuit for the heating elements 23 is closed, whereby the charge in the charge pocket 22 in the charge block 21 is heated and vaporized. The vapor fills the charge pocket 22 and is conducted through the tubular member 24 into the cavity 27 formed in the arc block 25. The electric circuit for the filamentary cathode 30 is closed, whereby the filamentary cathode 30 is heated and rendered electron-emissive. Then the electric circuit between the filamentary cathode 30 and the anode 31 is closed, whereby an arc discharge is struck therebetween,

4 electrons proceeding from the filamentary cathode 30 to the anode 31. The electrons proceeding from the filamentary cathode 30 to the anode 31 break up the molecular form of the compound of the vapor to a considerable extent, producing positive ions of the element which is to be enriched with a selected one of its isotopes.

The electric circuit between the arc block and the ion accelerating structure, including the plates 32, is completed, the plates 32 being at a high negative potential with respect to the arc block 25, whereby the positive ions are attracted and accelerated to the voltage impressed between the arc block 25 and the ion accelerating structure. More particularly, the positive ions proceed from the interior of the cavity 27 formed in the arc block 25, through the slot 26 formed in the wall thereof, and across the space between the plates 32 and the adjacent wall of the arc block 25, and thence through the slit 33 formed between the plates 32 into the interior of the tubular liner 41. The high-velocity positive ions form a vertical upstanding ribbon proceeding from the cavity 27 formed in the arc block 25 through the slot 26 and the aligned slit 33 into the tubular liner 41.

The collect-or block 35, as well as the tubular liner 41, is electrically connected to the ion accelerating structure, including the plates 32, whereby there is an electric field-free path for the high velocity positive ions, disposed between the plates 32 and the collector block 35 within the tubular liner 41. The high-velocity positive ions entering the adjacent end of the liner 41 are deflected from their normal straight-line path and from a vertical plane, passing through the slot 26 and the slit 33, due to the efiect of the relatively strong magnetic field maintained through the space within the tank 13 and the liner 41 through which the positive ions travel, whereby the positive ions describe arcs, the radii of which are proportional to the square roots of the masses of the ions and consequently of the isotopes of the element mentioned.

Thus, relatively light ions, a relatively light isotope of the element, describe an interior arc of relatively short radius and are focused through the slot 38 into the pocket 36 formed in the collector block 35; whereas relatively heavy ions, a relatively heavy isotope of the element, describe an exterior arc of relatively long radius and are focused through the slot 39 into the pocket 37 formed in the collector block 35. Accordingly, the relatively light ions are collected in the pocket 36 and are de-ionized to produce a deposit of the relatively light isotope of the element therein, while the relatively heavy ions are collected in the pocket 37 and are de-ionized to produce a deposit of the relatively heavy isotope of the element therein.

After all of the charge in the charge pocket 22 formed in the charge block 21 has been vaporized, all of the electric circuits are interrupted and the end wall 18 is removed so that another charge may be placed in the pocket 22 and subsequently vaporized in the manner explained above. After a suitable number of charges have been vaporized in order to obtain appropriate deposits of the isotopes of the element in the pockets 36 and 37 of the collector block 35, the end wall 19 may be removed and the deposits of the collected isotopes in the pockets 36 and 37 in the collector block 35 may be reclaimed.

Of course, it will be understood that the various dimensions of the parts of the calutron 10, the various electrical potentials applied between the various electrical parts thereof, as well as the strength of the magnetic field between the pole pieces 11 and 12,- are suitably correlated with respect to each other, depending upon the mass numbers of the several isotopes of the element which is to be treated therein. By way of illustration, it is noted that when the calutron 10 is employed in order to produce uranium, the compound of uranium which is suggested as a suitable charge in the charge block 21 is UCl as this compound may be readily vaporized and the molecular form of the vapor may be readily broken up to formpositive ions of uranium with great facility.

More particularly, the minor fraction of the UCL; vapor is ionized to form positive atomic ions including U+, U++, Cl+ and Cl++; and positive molecular ions including C1 Cl UCl UCl UCl UCl UCI UCl UCl+ and UCl++. Of these atomic and molecular ions only the singly ionized atomic ions U+ have the required ratio between mass and charge such that they are focused through the slots 38 and 39 into the pockets 36 and 37 formed in the collector block 35; the atomic ions U+ of masses 234 and 235 focusing through the slot 38 into the pocket 36, and the atomic ions U+ of mass 238 focusing through the slot 39 into the pocket 37, as previously noted.

The doubly ionized atomic ions U have such a ratio between mass and charge that they are deflected along an arc of shorter radius into engagement with the inner Wall of the liner 41, where they are de-ionized to form a deposit thereon. The singly and doubly ionized atomic ions Cl+ and Cl++ and the singly and doubly ionized molecular ions C1 and Cl have such small ratios between mass and charge that they are deflected along arcs of very short radii into engagement with the inner wall of the liner 41 adjacent the source region, where they are de-ionized to form neutral chlorine molecules, which gas is subsequently pumped from the tank 13 due to the operation of the vacuum pumping apparatus previously noted. Similarly, the doubly ionized molecular ions UCl UCl UCl and UCl have intermediate ratios between mass and charge such that they are deflected along arcs of intermediate radii into engagement with the inner wall of the liner 41 intermediate the source region and the collector region, where they are de-ionized to form a deposit thereon. Finally, the singly ionized molecular ions UCl UCl UCl and UCl+ have large ratios between mass and charge, such that they are deflected along arcs of large radii into engagement with the outer wall of the liner 41 intermediate the source region and the collector region, where they are de-ionized to form a deposit thereon.

The residue of U01 deposited on the parts of the calutron disposed in the source region thereof, principally upon the liner, is recovered by a water wash process, whereby various impurities including copper, iron, chrornium, nickel and carbon are introduced in the wash solution, due to the fact that the various parts of the calutron which are thus washed with water are formed of the materials mentioned.

Considering now the details of the recovery of the UCL, residue from the parts of a calutron disposed in the source region thereof, reference is made to'the portion of the flow diagram illustrated in Fig. 2. The parts of the calutron disposed in the source region thereof, principally the source-region end of the liner, are scrubbed and washed with hot water, whereby the residue of UCL, deposited thereon is dissolved; and various impurities, including copper, iron, chromium, nickel and carbon, are introduced in the water wash, due to the fact that the various parts of the calutron which are thus washed with hot water are formed of the materials mentioned. The wash water is then sieved in order to remove any solid impurities which may be picked up, such, for example, as small pieces of metal and carbon. These solid impurities may be either discarded or subjected to salvage treatment in order to recover any occluded uranium. The sieved wash. water is then treated with H by adding a slight excess of ten percent H 0 and agitating the solution in order to oxidize the various contained materials. For

example, the wash water prior to the step of oxidation 6 the uranium is put in solution as uranyl ion, suspended copper is put in solution as cupric ion, and other dissolved materials are putin their higher stable valence states if they are not already in such state. Carbon is not oxidized by this treatment. The effect of the oxidation on the various materials contained in the wash solution maybe indicated as follows:

Accordingly, the oxidized wash water contains at least the following: UO Cu++, Fe+++, Cr+++, Ni++ and C (carbon). The oxidized wash water is then filtered in order to remove C which may be discarded or subjected to salvage treatment in order to recover any occluded uranium.

In the event this filtrate is rather dilute, it may be concentrated by evaporation; otherwise this step is omitted. In the event the filtrate is concentrated by evaporation, the water vapor which is driven off is condensed and to it is added enough makeup water in order to provide a new wash solution, which is used again to wash the parts of the calutron disposed in the source region thereof, in the manner previously explained. This step, comprising condensing and re-using the water vapor which is driven off the filtrate incident to concentration by evaporation, is advantageous in view of the fact that any uranium entrained in the water vapor is not lost to the outside. The original filtrate mentioned above, or the concentrated filtrate following evaporation, in the event this step is employed, is then stored for further treatment.

Considering now the details of the recovery of the metallic uranium, reference is made to the portion of the flow diagram illustrated in Fig. 3. The inner surfaces of the first pocket of the collector of the calutron are etched with one of a number of acid solutions, whereby the deposit of metallic uranium is dissolved; and variout impurities including iron, chromium and nickel are introduced in the acid wash solution, due to the fact that the inner surfaces of the first pocket of the collector of the calutron which are thus etched with the acid solution are formed of stainless steel which comprises the materials mentioned. Accordingly, the wash acid contains at least the following ions:UO Fe+++, Cr+++, and Ni++.

A suitable acid wash solution which may be employed for the purpose mentioned comprises an aqueous solution containing HNO (approximately 12%). Another suitable acid wash solution comprises an aqueous solution containing HCl (approximately 2%) and H 0 (approximately 0.5%). A further suitable acid wash solution comprises an aqueous solution containing H (approximately 18%) and H 0 (approximately 10%). Thus, it will be understood that the first acid wash solution comprises an oxidizing acid, whereas the second and third acid wash solutions comprise a separate oxidizing agent in the form of H 0 Hence, the acid wash solution employed in any case produces an oxidizing effect upon both the uranium and the metal impurities which are dissolved therein.

In the event the wash acid is rather dilute in the ions mentioned, it may be concentrated by evaporation; otherwise this step is omitted. In the event the wash acid is concentrated by evaporation, the vapor which is driven off is condensed and to it is added enough makeup HNO or HCl and H 0 or H 80 and H 0 depending upon the composition of the original wash acid employed, in

greater than approximately 3%.

order to provide a new Wash acid'which is again used to wash the first pocket of the collector of the calutron,

' in the manner previously explained. This step, compristhe following ions: UO tt, Cut- Pe Cr+++, and

Ni reference is made to the portion of the flow dia gram illustrated in Fig. 4. In the event that the solution contains a reasonably largeifamountof copper. and nickel,

the solution is subjected to "a preliminary ammonia treatmentin order to eliminate a majority, if not substantially all, of the impurities mentioned; otherwise. this step is omitted. Assuming that the ammonia treatment is to be employed, the solution is treated either with excess NH gas or carbonate-free .NH OH, whereby (N1-I U O Fe(OH) and Cr(OH) are precipitated away from most of the copper and nickel in solution in the formof ammonia complex ions, Cu(l II-I and droxide and, chromic hydroxide, is, washed with water containing about 1% NH OH and 1% NH NO 'in order,

to eliminate occluded copper and nickel ammonia, complex ions. The filtrate containing'the copper and nickel ammonia complex ions is then discarded or. subjected to salvage treatment in order to recover any uranium contained; and the initially purified precipitate of The solution is then filtered and the precipitate, consisting of ammonium diuranate, ferric hyvapor are given off incident to the reduction.

that the Fe+++ ion content of the solution mentioned is greater than approximately 3% the ferric ion in the solution is complexed by the introduction of an agent which forms complex ion with ferric ion; on the other hand, in the event it is determined that the Fe+++ contained is less than approximately 3%, the last mentioned 1 treatment is omitted. Assuming that the solution contains greater than approximately 3% Pe ion, this ion is complexed by the addition to the solution of an appropriate agent such as lactic acid, acetic acid, fluoride ion, or Nullapon. tioned to the solution complexes the ferric ion, thereby eliminating the normal catalytic action of the ferric ion upon H 0 and consequently catalytic decomposition of the hydrogen peroxide in the subsequent purification. It will be understood that the presence of an appreciable amount of uncomplexed ferric ion in the solution will affect catalytic decomposition of hydrogen peroxide, thereby preventing complete precipitation of uranium peroxide, as explained more fully below.

Now assuming that a solution is obtained that contains UO Cu++, Ni++, Cr+++, and Fe+++ ions, which is conditioned for purification by the hydrogen peroxide precipitation step, this solution may be an original wash solution or a solution which has been derived after preliminary ammonia treatment, as explained above; either of which solutions may or may not have been treated with the ferric ion complexing agent. In any case, the solution does not contain undue amounts of copper or nickel impurities or uncomplexed ferric ion in an, amount tioned is fairly acid in view of its derivation and the pH The addition of the agent men- 5 i The solution menesses into crude UCl thereofisj adjusted within-the approximate range 1.0 to 3.0, and preferably within the range 1.5 to 3.0, by the addition of NH OI-I thereto. The acidified solution is then cooled to a temperature in the range of about 0 to 10 C.,' and preferably to approximately 5 C., and hydrogen peroxide, which may conveniently be in'the form of a 30% solution of H 0 is added to the solution in excess, so that there is more than enough H 0 to precipitate all of the uranium as the peroxide, UO -2H O.

The solution is kept cool'and is permitted to remain in a quiescent state until substantially complete settling of the uranium peroxide has taken place. Thereafter, the solution is filtered and the precipitate is washed with an aqueous solution that is approximately 2% in NH NO and 3% in H 0 The filtrate containing the copper, nickel, chromium and iron impurities is then discarded or subjected to salvage treatment in :order to recover any uranium contained and the purified UO -2H O precipitate is calcined to U0 at approximately325 0., whereby 0 gas isgiven off incident to the calcination. The purified uranium in the compound form U0 is then stored for further treatment or commercial use, as previously noted.

Considering now the details of the ultimate conversion of the batch of U0 to UClr, reference is made to the portion of the tlowdiagram illustrated in Fig. 5. The uranium trioxide may be converted .by alternative proc- In accordance with one process the U0 is finst reduced toUO by heatingwith CH at approximately 450 C., whereby CO CO gases and water The uranium dioxide is then reacted with C01, in the vapor phase at approximately 450 C. in a suitable'reaction chamber in order to produce crude UCL whereby COC1 CO CO and C1 gases are given off incident to the reaction. In accordance with an alternative process the U0 may be reacted directly with CCL; in the liquid phase in an autoclave at a temperature of approximately to C. and at a pressure of approximately 200 pounds per square inch gauge in order to produce U01 whereby COCl CO CO and C1 gases are given off incident to the reaction. The uranium pentachloride thus produced is then calcined or decomposed to produce crude UCl by heating to approximately 350 C., whereby C1 gas is given off incident to the calcination.

In any case, the crude uranium tetrachloride produced by either of the alternative processes indicated above is then sublimed in a suitable molecular still at approximately 600 C. in order to produce a sublimate of UCl whereby residues of U0 and UOCI are produced incident to the sublimation. The residues of U0 and UOCl are ultimately converted to UCl The UCL, thus produced is of very pure form.

The present process of recovering uranium from solutions is very effective in view of the fact that it is quite versatile. Thus, not only may uranium be reclaimed from a solution containing the impurities mentioned, copper, iron, chromium and nickel, but the solution may contain a variety of other impurities, such as manganese and zinc, without adversely affecting the purification. Moreover, the purification can be carried out as explained without particular reference to the identification of the impurities or the proportions contained in the wash solution; this feature is very advantageous in view of the fact that both the particular impurities as well as the related quantities thereof vary considerably among the different solutions derived from the different calutrons.

In view of the foregoing it is apparent that there has been provided an improved process of recovering, reclaiming. purifying and converting uranium, both in metallic and compound form on a large scale in commercial quantities.

Also, it will be understood that the present process may be suitably modified so that a compound of uranium other 9 than UCL; may be treated in the calutron. For example, the calutron, as well as the conversion steps of the process, may be modified, whereby UCl UBr etc. may be treated.

While there has been described what is at present con sidered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. The process for recovering uranium values from deposits formed on a metallic surface comprising treating said deposits to produce an oxidized acidic solution containing the uranium together with impurities of the group consisting of copper, iron, chromium, nickel, manganese and zinc, adjusting the pH of the solution within the approximate range 1.5 to 3.0, treating the acid solution with hydrogen peroxide to precipitate the uranium as uranium peroxide away from the metal impurities in the solution, separating the uranium peroxide precipitate from the metal impurities in the filtrate, and then calcining the uranium peroxide precipitate to produce uranium trioxide.

2. The process for recovering uranium values from deposits formed on a metallic surface comprising treating said deposits to produce an oxidized acidic solution containing the uranium together with impurities of the group consisting of copper, iron, chromium, nickel, manganese and zinc, treating said solution with ammonia to precipitate the uranium and the iron and chromium away from the other metal impurities which remain in the solution, separating the precipitate from the solution, dissolving the precipitate in acid, whereby the solution contains uranyl and ferric and chromic ions, adjusting the pH of the solution within the approximate range 1.5 to 3.0, treating said solution with hydrogen peroxide to precipitate the uranium as uranium peroxide away from the iron and chromium impurities in the solution, and then separating the uranium peroxide precipitate from the solution.

3. In a process for recovering uranium values from deposits formed on a metallic surface, the steps comprising producing from said deposits an oxidized acidic solution containing lsaid uranium values together with impurities including at least one material selected from the group consisting of copper, iron, chromium, nickel, manganese and zinc, adjusting the pH of the solution to within the range 1.0 to 3.0, then adding hydrogen peroxide 10 to the solution to precipitate the uranium as uranium peroxide away from the impurities in the solution, and separating the uranium peroxide from the solution.

4. The process for recovering the uranium values from deposits formed on a metallic surface containing materials :of the group consisting of copper, iron, chromium, nickel, manganese and Zinc, comprising treating said deposits with an oxidizing acidic solvent to produce a solution containing the uranium together with said materials as impurities, adjusting the pH of the solution to the range of about 1.0 to 3.0, cooling the solution to a temperature in the range of about 0 to 10 C., then precipitating the uranium as uranium peroxide away from the impurities in the solution by the addition of hydrogen peroxide, and separating the uranium peroxide from the solution.

5. in a process of recovering uranium values from deposits formed on a metallic surface including the steps of producing an oxidized acidic solution containing the uranium together with impurities including more than about 3% of ferric ion, adjusting the pH of the solution to the range of about 1.0 to 3.0, precipitating the uranium as uranium peroxide away from the impurities in the solution by means of hydrogen peroxide, and separating the uranium peroxide from the solution; the step comprising, complexing the iron in the solution prior to said precipitation step to prevent the ferric ion catalyzed decomposition of the hydrogen peroxide employed therein.

6. The process as defined in claim 3, wherein said deposits comprise the residue of a water-soluble uranium compound formed with a metallic surface, and, in which,

water is the solvent employed in producing said oxidized acidic solution.

7. The process as defined in claim 3, wherein said deposits comprise the residue of uranium tetrachloride formed on a metallic surface, and, in which, water is the solvent employed in producing said oxidized acidic solution.

8. The process as defined in claim 4, wherein said deposits comprise metallic uranium deposits formed with said metallic surface.

References Cited in the file of this patent Fairley: Journal of the Chemical Society, vol. 31, pp. 127-443 (1877).

Rosenheim et al.: Uranium Tetroxide Dihydrate, Chemical Abstracts, vol. 23, p. 4634 (1929).

Claims (1)

1. 2. THE PROCESS FOR RECOVERING URANIUM VALUES FROM DEPOSITS FORMED ON A METALLIC SURFACE COMPRISING TREATING SAID DEPOSITS TO PRODUCE AN OXIDIZED ACIDIC SOLUTION CONTAINING THE URANIUM TOGETHER WITH IMPURITIES OF THE GROUP CONSISTING OF COPPER, IRON, CHROMIUM, NICKEL, MANGANESE AND ZINC, TREATING SAID SOLUTION WITH AMMONIA TO PRECIPITATE THE URANIUM AND THE IRON AND CHROMIUM AWAY FROM THE OTHER METAL IMPURITIES WHICH REMAIN IN THE SOLUTION, SEPARATING THE PRECIPITATE FROM THE SOLUTION, DISSOLVING

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