US2782117A

US2782117A - Method of reclaiming uranium

Info

Publication number: US2782117A
Application number: US674648A
Authority: US
Inventors: Harley A Wilhelm; C F Gray
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-06-05
Filing date: 1946-06-05
Publication date: 1957-02-19
Anticipated expiration: 1974-02-19

Description

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. invention relates to the ieclamation ofl'uraniium filings and turnings from the waste of metallurgical operations with uranium and recasting the reclaimed uranium.

.gIhc reclamation of uranium from waste turnings .and 1 filings is complicated by the necessity of achieving aprodnot of a highdegree of purity andalso complicated by thehigh afiinity of this metal for oxygen. .An object of this inventionfis the recasting of uranium from recl airned uranium Waste. i v

An othernobject. of this invention is the provision of a process 'for reclaiming uraniumfrom uranium waste and casting the reclaimed uranium with a suitable reducing metal, such as for example, an alkali or alkaline earth metal, to form a uranium casting with the minimum of oxidation and a high degree of purity.

The above and other objects and features of this invention will be apparent from the following detailed description of a preferred embodiment.

In casting reclaimed uranium, it has been discovered that highly satisfactory results are obtained by the inclusion of an alkali or an alkaline earth metal in the melt. According to this method the uranium may be processed from any condition in uranium waste to pure uranium billets with a high percentage recovery of uranium and a minimum of oxidation.

In preparing the waste uranium'for reclamation, the scrap metal is sorted and searched for relatively large pieces of foreign material which are removed by hand. The sorted uranium waste is then .cut or shredded by known methods, cleaned and then re-examined for foreign material. The uranium thus processed, is then mixed with a suitable alkali or alkaline earth metal and pressed into billets for casting into biscuits or ingots.

The process generally involves the steps of sorting the uranium waste and separating out foreign matterby inspection and magnetic attraction, followedby passing the metal through a cutter in which a cleaning solution acts as a coolant and also serves to partially degrease and clean the uranium pieces. fThe steps after cutting involve the further cleaning'and degreasing of the cut uranium in a cleaning machine followed by centrifugal 2 The uraniurn particles are next cut and in this stage the inspected uranium is placed in a spray containing a wetting agent and a suitable detergent, such as a 3% solution of sodium silicate. Such'a spray is directed so as to follow the uranium particles into the cutter. .;The

cutting is preferably, done by a hammer-type mill to given an optimum amount of abrasive and bending action to theparticles and thereby remove the oxide scale. ,Theuranium turnings should be cut only fine enough that the particleswill flow from one container to another without hanging together objectionably.

The 3% silicate solutionmentioned above is highly satisfactory in that itserves both as acoolant and as a degreasing agent, l-lo wever any suitable detergent solution or high flash-point, non-reactive liquid or solution maybe used as a coolant in the cutting operation In any event cutting the uranium should be conducted while .-the uranium is wetted and cooled with a liquid coolant inorder to prevent fire. V v

The next step in the process is that of washing the uranium particlesas they aredelivered from the cutter. The cleaning operation involves washing the uranium particles with a suitable detergent solution followed by rinsing twice in cold water. An additional step which aids in the removal ofthe oxide'film may be employed by dipping or otheiwiseallowing the uranium particles to be treated with a hydrogen peroxide-sulfuric acid bath for several minutes. Such a solution attacks the oxide layer much more rapidly than it attacks the uranium metal. a centrifuge equipped with a blower which forces heated C.) air through the mass as it is being whirled.

drying in a stream of warm air, after which the cleaned uranium cuttings are subjected to reexamination for foreign matter. The final step in the preparation for casting entails pressing the reclaimed uranium with the desired reducing metal.

Asexamples of suitable reducing metals there may be stage of operation from large pieces of iron and steel.

and centrifuged to remove the moisture.

An additional oxide removal step is optional. This removal may be effected by nitric acid, hydrogen peroxide in sodium carbonate, or hydrogen peroxide in sulfuric acid.

After removal of the cleaned particles from the final rinse the wet particles are placed in a centrifuge drier After draining, the particles are then separated in oven trays in layers not over of an inch in depth and dried for 15 minutes at 60 C. in a vacuum of 20 in mercury or less.

' The dried material from the vacuum drying oven is deposited on a sorting belt and slowly passed along by the sorting belt in a thin layer so that the sorting operator may remove small pieces of non-magnetic material. The uranium particles are then passed over a spout type magnetic separator for final separation after which the uranium is ready to be pressed.

Applicants have found that the yield of uranium may be substantially improved by melting the cleaned uranium with a small amount of alkali metal or alkaline earth metal. Use of as little as 0.05 to 6.1 precent by weight of such a metal based upon the weight of uranium improves the yield of uranium by several percent. Higher amountsof the alkali or alkaline earth metal may be used although such excesses are unnecessary. The amount of such metal used is almost never as muchas 5 percent of the weight of theuranium and in general is below one percent. A

In the case of magnesium, for example, the dried uranium particles are mixed with the magnesium in proportions of about 1 part by weight of magnesium to 1606 parts by weight of uranium and are pressed into briquettes 7 From the foregoing it will be seen that an improved.

After the metal has been rinsed it is placed in V method of reclaiming uranium from waste material has,

been discovered, comprising cleaning and degreasing the uranium and casting the cleaned uranium with magnesium or other suitable alkali or alkaline earth metals.

What is claimed is: i V

1. In a process for the reclamation of uranium metal from compositions comprising uranium metal particles partially coated with an oxide scale surface, the steps which comprise contacting the uranium particles with an oxide scale-removing solution, removing said solution therefrom, intimately admixing magnesium metal with the uranium particles to form a mixture thereof, compressing said mixture into briquettes, smelting said compositions and the magnesium metal within a temperature from'about 12501 C to about 1400 0., and'then casting the uranium metal "within a' temperature range from about 1280 C. to about 1300 C.

2. The process of claim 1 wherein the oxide scale,- removing solution contains a solution of hydrogen peroxide and sulfuric acid. Y

3; A process for reclaiming uranium from waste metal particles comprising washing the particles with a detergent, rinsing said particles with water to remove adhering detergent, immersing the particles into an oxideremoving solution, drying the particles, mixing said particles with from 0.05 to 1% of a metal selected from the group consisting of alkali metals and alkaline earth metals, melting and heating the mixture to from 1350 to 1375 C., and pouring the metal into a mold at a temperature between 1280 and 1300" C.

. Under the Auspices of the U. S. Government.

' 4. A process for reclaiming uranium from waste metal particles comprising washing the particles with a detergent, rinsingsaid particles with water to remove adhering detergent, immersing the particles into a mixture of hydrogen peroxide and sulfuric acid to remove any oxide, rinsing with water, drying the particles, mixing said particles with from 0.05 to.0.1% of a metal selected from the group consisting of alkali metals and alkaline earth metals, melting and heating the mixture to from 1350 to 1375 C., and pouring the metal into a mold at a temperature between 1280 and 1300" C.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES 0 Thews: Metallurgy of White Metal Scrap and Residue, published by D. Van Nostrand Co., Inc., 250 Fourth Avenue, N. Y., 1930, page 4.

Smyth, A General Account of the Development of Methods of Using Atomic Energy for Military Purposes 1940-45. August 1945, page 27. For sale by the Superintendent of Documents, Washington, D. C.

Claims

1. IN A PROCESS FOR THE RECLAMATION OF URANIUM METAL FROM COMPOSITIONS COMPRISING URANIUM METAL PARTICLES PARTIALLY COATED WITH AN OXIDE SCALE SURFACE, THE STEPS WHICH COMPRISES CONTACTING THE URANIUM PARTICLES WITH AN OXIDE SCALE-REMOVING SOLUTION, REMOVING SAID SOLUTION THEREFROM, INTIMATELY ADMIXING MAGNESIUM METAL WITH THE URANIUM PARTICLES TO FORM A MIXTURE THEREOF, COMPRESSING SAID MIXTURE INTO BRIPUETTES, SMELTING SAID COMPOSITIONS AND THE MAGNESIUM METAL WITHIN A TEMPERATURE FROM ABOUT 1250*C. TO ABOUT 1400*C., AND THEN CASTING THE URANIUM METAL WITHIN A TEMPERATURE RANGE FROM ABOUT 1280*C. TO ABOUT 1300*C.