MX2014005312A - Extraction of uranium from wet-process phosphoric acid. - Google Patents

Abstract

In a preferred embodiment, a process for extracting uranium from wet process phosphoric acid (WPA) comprises separating uranium from WPA to produce a uranium-laden solution stream and a uranium-free WPA stream. The stream of uranium-laden solution is then contacted with an ion exchange resin. The uranium species bound to the ion exchange resin are eluted upon contacting the resin with a solution comprising anions to produce a stream of eluent loaded with uranium. The eluent stream charged with uranium is treated to provide a product containing uranium.

Description

URANIUM EXTRACTION FROM PHOSPHORIC ACID OF PROCEDURE IN WETLAND Cross reference to related requests This claims the benefit of the provisional US application no. 61 / 553,742 filed on October 31, 2011 and titled "Uranium Extraction Processes" and is a continuation-in-part of the US application no. 13 / 931,112 filed on July 23, 2012 and entitled "Extraction of Uranium from Wet-Process Phosphoric Acid" (Uranium extraction from wet process phosphoric acid), claiming both the benefit of the US application no. 12 / 510,294 (now US Patent No. 8,226,910) filed on July 28, 2009 and entitled "Estraction of Uranium from Wet-Process Phosphoric Acid" (Extraction of uranium from wet process phosphoric acid), which claims the benefit of the provisional US application no. 61 / 161,133 filed on March 18, 2009 and the provisional US application no. 61 / 085,177, filed July 31, 2008. Each of these references is incorporated herein by reference in its entirety.

Field of the invention The invention relates to the field of extracting uranium from the wet process phosphoric acid.

Background Phosphoric acid (H3PO4) for use in the production of fertilizer is normally produced by a wet process during which the naturally occurring phosphate rock is reacted with sulfuric acid to provide the so-called wet process phosphoric acid (WPA) Depending on the source of the phosphate rock, it may contain valuable metals such as uranium, vanadium and yttrium, which are dissolved by sulfuric acid and form constituents of WPA impurities.

In the United States, plants have been in operation since the early 1950s to recover valuable amounts of uranium from WPA. However, with fluctuations in the spot price of uranium, it is important that it can be extracted from the WPA in a cost-effective manner. To date, many of the plants that have operated uranium extraction processes have used the solvent extraction process to extract the uranium from the WPA. Another process that has received more attention in recent times is an ion exchange process, whereby WPA containing uranium is loaded onto an ion exchange resin. The WPA is discharged from the resin, leaving the uranium bound to the resin. The uranium is then eluted from the resin. U.S. Patent No. 4,599,221 (Ketzinel et al.) Describes such a process for extracting uranium from WPA using an ion exchange process.

Unfortunately, the known uranium extraction processes are not all that simple to perform. Part of the problem is that the WPA is a raw material containing a range of organic and inorganic contaminants or species that can interfere with the extraction process and have a profound effect on the commercial viability of the process.

The applicant has previously discovered that certain process efficiencies are achieved by decreasing the WPA iron concentration, reducing the valence of any ferric iron remaining in the WPA to ferrous iron, and then extracting the uranium compounds from the WPA. These details are described in U.S. Patent No. 8,226.91 0, which is incorporated by reference in its entirety.

There is a continuing need for other improved processes to extract uranium from WPA that overcome one or more of the problems associated with the processes of others and / or that are more efficient.

BRIEF DESCRIPTION OF THE INVENTION In a first aspect, the invention provides a process for extracting uranium from wet process phosphoric acid (WPA), the process comprising: (a) separating uranium from WPA to produce a stream of uranium-laden solution and a stream of WPA lacking uranium; (b) contacting the uranium-charged solution stream with an ion exchange resin; (c) eluting the uranium species bound to the ion exchange resin by contacting the resin with a solution comprising anions to produce a drained eluent stream of uranium; and (d) treat the current of eluyente carada of uranium to provide a product containing uranium.

In some embodiments, the anions used to elute the uranium species in step (c) are selected from the group consisting of chloride anions, sulfate anions, nitrate anions and combinations thereof.

In some embodiments of the first aspect of the invention, step (a) is preceded by a step of valence reduction comprising reducing the valence of ferric ions in the WPA. The valence reduction step can be performed by chemical reduction, such as by the addition of metallic iron, ferro-phosphorus alloy or ferro-silicon alloy; or by electrochemical reduction (ER).

In some embodiments of the first aspect of the invention, step (a) and / or valence reduction weight (if used) can be preceded by an iron removal step. The step of iron removal involves decreasing the iron concentration in the WPA by decreasing the amount of iron species dissolved in the WPA in relation to the amount of uranium species in the WPA to produce a WPA of decreased iron content having a kind of uranium in it. The concentration of iron in WPA can be decreased by precipitating at least some of the iron present in WPA as ammonium iron phosphate.

In a second aspect, the invention provides a process for extracting uranium from the wet process phosphoric acid (EPA), the process comprising: (a) contacting the WPA loaded with uranium with a first ion exchange resin to form WPA lacking uranium; (b) separating the WPA lacking uranium from the first ion exchange resin; (c) oxidizing the uranium species in the first ion exchange resin by contacting the first ion exchange resin with an oxidant; (d) contacting the first ion exchange resin with ammonia to remove the impurities from the resin, the impurities being vanadium ions, organic species, or a combination thereof; (e) separating the impurities from the first ion exchange resin; (f) removing the oxidized uranium species from the first ion exchange resin by contacting the resin with ammonium carbonate to form a stream of ammonium carbonate enriched with uranium; (g) contacting the ammonium carbonate stream enriched with uranium with a second ion exchange resin to form ammonium carbonate lacking uranium; (h) separating the ammonium carbonate lacking uranium from the second ion exchange resin; and (i) eluting the uranium species from the second ion exchange resin to form an uranyl solution.

In some embodiments, the oxidant is selected from the group consisting of: air, oxygen, hydrogen peroxide, WPA, and combinations thereof.

In some embodiments, the elution in step (i) is performed using a solution comprising anions selected from the group consisting of chloride anions, nitrate anions, sulfate anions, and combinations thereof.

In some embodiments of the second aspect of the invention, the step (a) can be preceded by a step of valence reduction comprising reducing the valence of ferric ions in the WPA. The valence reduction step can be performed by chemical reduction, such as by the addition of metallic iron, ferro-phosphorus alloy or ferro-silicon alloy; or by electrochemical reduction (ER).

In some embodiments of the second aspect of the invention, step (a) and / or the valence reduction step (if used) may be preceded by an iron removal step. The step of iron removal involves decreasing the iron concentration in the WPA by decreasing the amount of iron species dissolved in the WPA in relation to the amount of uranium species in the WPA to produce a WPA of decreased iron content having species of uranium in it. The concentration of iron in WPA can be decreased by precipitating at least some of the iron present in WPA as ammonium iron phosphate.

In a third aspect, the invention provides a process for extracting wet process phosphoric acid uranium (WPA), the process comprising: (a) contacting WPA loaded with uranium with an oxidant to form an oxidized WPA stream; (b) contacting the oxidized WPA stream with an organic solvent; (c) separating a stream of organic solvent enriched with uranium from a stream of aqueous WPA; (d) contacting the organic solvent stream enriched with uranium with a stream of ammonium carbonate to form a stream of ammonium carbonate enriched with uranium; (and) contact the ammonium carbonate stream enriched with uranium with an ion exchange resin; (f) separating a current of ammonium carbonate lacking uranium from the ion exchange resin; (g) contacting the ion exchange resin with a solution comprising chloride ions; and (h) separating a uranyl solution from the ion exchange resin.

In some embodiments, the organic solvent used in step (b) comprises a di (2-ethylhexyl) phosphoric acid and trioctylphosphine oxide (i.e., a "DEHPA TOPO" system).

In some embodiments of the third aspect of the invention, the valence reduction step is preceded by a step of iron removal. The step of iron removal involves decreasing the concentration of iron in the WPA by decreasing the amount of iron species dissolved in the WPA to produce a WPA of decreased iron content having uranium species in it. The concentration of iron in WPA can be decreased by precipitating at least some of the iron present in WPA as ammonium iron phosphate.

In some embodiments of any of the first, second or third aspect of the invention, the uranyl solution can be further treated to provide a product containing uranium. The additional treatment may comprise a precipitation step.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference is made to the following detailed description, taken in connection with the drawings companions illustrating various embodiments of the present invention, in which: FIG. 1 illustrates a general flow diagram for a process according to a first exemplary embodiment of the invention; FIG. 2 illustrates a general flow diagram for a process according to a second exemplary embodiment of the invention; FIG. 3 illustrates a general flow diagram for a process according to a third exemplary embodiment of the invention; FIG. 4 illustrates a general flow diagram for a process according to a fourth exemplary embodiment of the invention; FIG. 5 illustrates a general flow diagram for a process according to a fifth exemplary embodiment of the invention; Y FIG. 6 illustrates a general flow diagram for a process according to a sixth exemplary embodiment of the invention.

Detailed description of preferred modalities The invention will now be described with reference to the accompanying drawings in which the preferred embodiments of the invention are shown. However, the invention can be encompassed in many different forms and should not be construed as limited solely to the embodiments described herein.

FIG. 1 is a flow diagram of a first exemplary embodiment of the invention, which is a process for extracting uranium from wet process phosphoric acid (WPA) 12. Process 10 comprises a first separation step 14, in which the Uranium is separated from WPA in a primer, ion exchange (IX) or solvent extraction step (SX). The first separation step 14 provides a charged solution current of uranium 16 and a current of WPA lacking uranium 1 8. The loaded solution stream of uranium 16 is then contacted with an anion exchange resin in a secondary ion exchange step. 20. During the ion exchange step 20, the uranium species is linked to the anion exchange resin. The bound uranium species are then eluted from the anion exchange resin by contacting the resin with a solution comprising chloride ions 22 to produce an eluent stream charged with uranium 24. Other anions that could be used to elute the uranium species bound from the anion exchange resin include nitrate and sulfate. In some embodiments, the secondary ion exchange step 20 may be performed using a cation exchange resin or a chelating resin. The eluent stream charged with uranium 24 is then treated in an additional treatment step 26 to provide a product containing uranium 28.

The wet process phosphoric acid (WPA) 12 can be any WPA feed. WPA is normally produced by reacting a phosphate rock with sulfuric acid. Before being fed in the process of the present invention, WPA can be treated in one or more pre-treatment steps. For example, feeding WPA 1 2, at a concentration of approximately 30% WPA can contain a significant amount of suspended solids, mainly sodium and gypsum fluorosilicates, which can cause problems for the later stages of the process. In these cases, the WPA can be clarified. The clarification step may involve filtering the WPA to remove the insoluble matter. Specifically, the clarification step can use an existing clarifier in a WPA plant and additional clarifiers, which complement pre-existing clarifiers, are used to reduce total suspended solids (TSS) and decrease process fluctuations due to current changes. above. In these modalities, the WPA can be clarified, for example, in conventional clarifiers. The clarifiers are dosed with flocculant to encourage the precipion of suspended solids. A lower flow of the clarified can be transferred back to the clarifier with the overflow being transferred to the next stage of the process.

Preferably, WPA 12 is an aqueous solution comprising from about 20% by weight to about 40% by weight of WPA. In some embodiments, WPA 12 is an aqueous solution comprising about 30 wt% of WPA.

The first separation step 14 can be an ion exchange step (IX) or a solvent exchange step (SX).

In some embodiments, the first separation step 14 is an ion exchange step. The WPA 12 feed (which may or may not be a WSPA of decreased iron content or a reduced WPA of reduced valence as described in more detail below) is transferred to one or more ion exchange columns (IX) containing a chelating ion exchange resin. Normally, each train of columns IX will normally have an initiative column, a capture column (or queue) and a column in elution / idle mode at some point. The WPA current lacking uranium 1 8 is returned to the WPA maintenance tanks to be used for fertilizer production, etc.

Once a column IX in the train is loaded it is taken offline and eluted. The elution process comprises eluting column IX with eight bed volumes (BV) of carbonate solution. Uranium forms a stable, stable uranyl tricarbonate complex in the ammonium carbonate solution, while impurities such as iron will form insoluble compounds. The precipid iron can be removed from the eluate using filters before entering the secondary IX, where additional rejection of impurities occurs. The loaded uranium 16 solution stream containing uranyl carbonate from the first separation step 14 is then passed to the secondary anion exchange step 20, to extract the uranium on the resin, and to recycle the ammonium carbonate. If necessary, a nominal 10% bleed can be removed to control the accumulation of impurities in the eluent and can be replaced with fresh ammonium carbonate solution. The uranium bound to column IX in the secondary anion exchange step 20 is then eluted using a solution containing chloride ions 22 to produce a product containing uranium 28. Other anions that can be used for this step include sulfate and nitrate.

In some other embodiments, the first separation step 14 is a solvent extraction step. The WPA 12 feed (which may or may not be a WPA of decreased iron content or a reduced WPA of reduced valence as described in more detail below) may be transferred to an oxidation step in which the WPA is oxidized with an air / oxygen mixture and / or a chemical oxidant, such as hydrogen peroxide or a stream of WPA. The oxidized WPA is then transferred to a solvent extractor. The solvent extraction step 14 uses any organic solvent that has a high affinity for uranium. Examples of solvents of this type include a DEHPA TOPO system (di-2-ethylhexyl phosphoric acid and trioctylphosphine oxide). In some embodiments, the solvent extraction step 14 is a multi-extraction DEHPA TOPO system (di-2-ethylhexyl phosphoric acid and trioctylphosphine oxide), nominally with a concentration of 0.5M DEHPA and 0.125M TOPO in an organic diluent based on kerosene, operated at around 40 ° C. Additional details of the DEH PA TOPO can be found in Hurst et al. , Ind. Eng. Chem. Process Des. Develop. , 1 972, 1 1, 1 22-128, the details of which are incorporated herein by reference. The WPA current lacking uranium 1 8 is returned to the WPA maintenance tanks to be used for fertilizer production, etc.

In some embodiments, the fertile organic phase is extracted with ammonium carbonate to provide the loaded solution stream of uranium 16.

The process described in relation to FIG. 1 can be varied for add additional steps as required. For example, different sources of phosphate rock have different compositions. As a result, WPA inlet currents from different sources of phosphate rock will normally have different impurities, any of which can interfere with the uranium extraction process. As a result, additional steps can be incorporated into the process of the present invention to improve the efficiency of uranium mining. Some additional embodiments of the process of the present invention incorporating the additional steps will now be described.

The FI G. 2 is a flow chart describing a second exemplary embodiment of the invention, which is a process for extracting uranium from wet process phosphoric acid (WPA) 1 2. Process 40 comprises contacting WPA loaded with uranium 1 2 with a first ion exchange resin in a first step of ion exchange 42. The first ion exchange resin is a resin ultant. A stream of WPA lacking urea 44 is separated from the first ion exchange resin and the resin is contacted with an oxidant 52 in an oxidation step 54 under conditions to oxidize substantially all of the uranium species in the resin. The first ion exchange resin is then contacted with a stream comprising ammonia 46 in an extraction step 48 under conditions to remove at least some of any vanadium ion or nest and / or organic species from the resin. A stream enriched with organic species and / or vanadium 50 is then separated from the first ion exchange resin. The first ion exchange resin is subsequently contacted with a stream of ammonium carbonate 56 in an elution step 58 under conditions to remove the oxidized uranium species from the resin and provide a stream of ammonium carbonate enriched with uranium 60. The current of ammonium carbonate enriched with uranium 60 is then contacted with an anion exchange resin in a second ion exchange step 62 and an ammonium carbonate stream devoid of uranium 64 is separated from the second ion exchange resin. The uranium species is then eluted from the second ion exchange resin in an elution step 66 to provide a solution of uranyl 68. The elution step 66 can be enhanced using a solution comprising suitable anions, such as chloride, nitrate or sulfate .

Fig. 3 is a flow chart describing a third exemplary embodiment of the invention, which is a process for extracting uranium from wet process phosphoric acid (WPA) 12. Process steps 42, 48, 54, 58, 62 and 64 in this embodiment are the same as those described with respect to the second exemplary embodiment and shown in FIG. 2. In the third embodiment, the first ion exchange step 42 is preceded by a valence reduction step 70. The valence reduction step 70 comprises reducing the valence of ferric ions in the WPA 12 to produce a WPA of reduced valence. 72, which is then subjected to a first step of ion exchange 42. The step of valence reduction 70 can be important because any ferric iron has a detrimental effect on subsequent process steps of the uranium extraction process. The ion exchange resin (IX) used in the subsequent step (s) for the extraction of uranium has a high affinity for charging ferric ions (Fe3 +), which inhibits the uranium loading. For this reason, it is preferable that the iron in the WPA 12 feed is in the ferrous state (Fe2 +).

The valence reduction in the valence reduction step 70 can be performed by contacting the WPA containing ferric ions (Fe3 +) with a suitable reducing agent. Suitable agents for this purpose include (but are not limited to): metallic iron; ferro-phosphorus alloy; and ferro-silicon alloy. Alternatively or additionally, the valence reduction in the valence reduction step 70 can be performed by reducing the ferric ions (Fe3 +) in the WPA in an electroreduction step.

In some embodiments, the valence reduction step 70 comprises adding metallic iron to a reactor containing WPA 12 in order to reduce ferric iron to ferrous iron. For example, the concentrate can be pumped into three stirred tanks with a total residence time of three hours. Powdered or granular iron can be added in the first of two reactors to a stoichiometric equivalent of 120% (in relation to the amount of ferric iron). Alternatively, the metallic iron could be substituted with or used in combination with ferro-phosphorus or ferro-silicon alloy.

In some modalities, the valence reduction step 70 It comprises electroreduction. Electroreduction can be advantageous because no chemical species are added to the WPA and it is easier to control the electrolyte reduction. In one form of the electroreduction stage, the WPA feed is transferred to electroreduction cells operated in a continuous manner.

FIG. 4 is a flow chart descrg a fourth exemplary embodiment of the invention, which is a process for extracting uranium from wet process phosphoric acid (WPA) 12. Process steps 42, 48, 54, 58 , 62, 64 and 70 in this embodiment are the same as those described with respect to the third exemplary embodiment and shown in FIG. 3. In the fourth embodiment, the valence reduction step 70 is preceded by an iron removal step 74. The iron removal step 74 comprises decreasing the amount of iron species dissolved in the WPA in relation to the amount of iron removal. uranium species in the WPA to produce a WPA of decreased iron content 76 having a uranium species in it 76. The WPA of decreased iron content 76 has a lower amount of dissolved iron species than the crude WPA 12. The WPA of decreased iron content 76 is then subjected to the valence eduction step 70, which involves subjecting the WPA of decreased iron content76 to a reduction step, wherein the valence of dissolved iron species remaining in the WPA content of reduced iron 76 is reduced.

The objective of the iron removal stage 74 is to decrease the iron content. This can be done by removing most of the Total iron present through precipitation of an iron ammonium phosphate compound (IAP) from the feed or pre-treated WPA. The IAP precipitation step is designed to remove a portion of ferric iron, as a partial step before the valence reduction step. Additionally, the precipitation of IAP reduces the scale species (fluorosilicate and gypsum) in the WPA of decreased iron content 76 before an ion exchange step, which, in turn, improves the operability of the ion exchange step.

In the iron removal step of the exemplary embodiments, WPA is transferred to a small pre-mix size, ammonia is added to a stoichiometric excess of approximately 300 -1000% of the ammonia requirements calculated for the formation of IAP. From the pre-mix tank, the treated stream is transferred to overflow reactors. The treated stream has a total residence time of 7 to 1 2 hours in the overflow reactors to allow the completion of the IAP precipitation process. The overflow of the overflow reactor is transferred to a centrifuge, another solid liquid separation device, where IAP is separated from the WPA. The WPA of decreased iron content 76 (low solid concentration) is then transferred to the 70 valence reduction step.

FIG. 5 is a flowchart describing a fifth exemplary embodiment of the invention, which is a process 80 for extracting uranium from wet process phosphoric acid (WPA) 12. Process 80 comprises an oxidation step 82 in the which the WPA loaded with uranium 12 is contacted with an oxidant 84 to provide an oxidized WPA stream 86. The oxidized WPA stream 86 is then contacted with a solvent 88 comprising di (2-ethylhexyl) phosphonic acid and trioctylphosphine oxide in a solvent extraction passage 90. A stream of organic solvent enriched with uranium 92 is then separated from an aqueous stream containing WPA 94 and the stream of organic solvent enriched with uranium 92 is contacted with a solution of ammonium carbonate 94 in one step of extraction 96 under conditions to provide a stream of ammonium carbonate enriched with uranium 98. The ammonium carbonate stream enriched with uranium 98 is then contacted with an ion exchange resin in a 100 ion exchange step. Ammonium lacking uranium 102 is separated from the ion exchange resin and the resin is contacted with a solution containing chloride ions 104 and a uranyl solution 106 is separated from the ion exchange resin.

FIG. 6 is a diagram and flow describing a sixth exemplary embodiment of the invention, which is a process 80 for extracting uranium from wet process phosphoric acid (WPA) 1 2. Process steps 82, 90, 96 and 100 in this embodiment are the same as those described with respect to the fifth exemplary embodiment and shown in FIG. 5. In the sixth embodiment, the solvent extraction step 90 is preceded by an iron removal step 108. The iron removal step 108 comprises decreasing the iron removal step. iron concentration in WPA 12 to produce a WPA of decreased iron content 1 10 which is then subjected to solvent extraction step 90. The iron removal step can be carried out as previously described.

In any of the exemplary embodiments, the product containing uranium 28 or uranyl solution 106 can be further treated to produce a commercial uranium product. In some embodiments, uranium can be precipitated from the product containing uranium-28 or uranyl-106 solution. The step of precipitating the uranium from the product containing uranium-28 or uranyl-106 solution comprises acidification and removal of generated carbon dioxide, formation of an uranyl peroxide through the addition of hydrogen peroxide, as well as caustic soda as required to maintain an adequate pH for the precipitation reaction. The step of drying the precipitated product involves thickening the precipitate in a high performance thickener and drying in a low temperature dryer at 260 ° C.

The product containing uranium 28 or uranyl solution 1 06 is pumped into the first of three tanks in series. Hydrogen peroxide and caustic soda are added to allow the precipitation of uranium from oxides. The total residence time in the precipitation reactors is three hours. The lower flow is transferred to a thickener, followed by the drying of the precipitate at about 260 ° C and subsequent drums drumming and finally packed in shipping containers.

Throughout this specification, the word "understand", or variations such as "comprises" or "understanding", will be understood as involving the inclusion of an element, integer or declared step, or group of elements, integers or steps, but not the exclusion of some other element, integer or step, or group of elements, integers or steps.

All publications mentioned in this specification are incorporated herein by reference. Any discussion of documents, acts, materials, devices, articles or the like, which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these issues are part of the prior art base or were general knowledge common in the field relevant to the present invention as it existed in Australia or elsewhere before the date of priority of each claim of this request.

Persons skilled in the art will appreciate that numerous variations and / or modifications can be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. Therefore, the present modalities are going to be considered in all aspects as illustrative and not limiting.

Many modifications and other embodiments of the invention will come to the memory of one skilled in the art having the benefit of the teachings presented in the descriptions above and the associated drawings. Therefore, it is understood that the invention is not limited to the specific embodiments described, and that modifications and modalities are intended to be included within the scope of the claims supported by this description.

Claims (19)

1. CLAIMS 1 . A process for extracting uranium from wet process phosphoric acid (WPA), the process comprising: (a) separating uranium from WPA to produce a stream of uranium-laden solution and a current of WPA lacking uranium; (b) contacting the uranium-charged solution stream with an ion exchange resin; (c) eluting the species of uranium bound to the ion exchange resin by contacting the resin with a solution comprising anions to produce a stream of eluent charged with uranium; Y (d) treating the eluent stream charged with uranium to provide a product containing uranium. 2. The process of claim 1, wherein the anions used to elute the uranium species in step (c) are selected from the group consisting of: chloride anions, sulfate anions, nitrate anions and combinations thereof. 3. The process of claim 1, wherein step (a) is preceded by a step of valence reduction comprising reducing the valence of ferric ions in the WPA. 4. The process of claim 3, wherein step (a) and / or the valence reduction step (if used) is preceded by a step of iron removal. 5. The process of claim 1, wherein step (a) is preceded by: decrease the amount of iron species dissolved in the WPA in relation to the amount of uranium species in the WPA to produce a WPA of decreased iron content having a uranium species in it; Y subjecting the WPA of decreased iron content to a reduction step, wherein the valence of dissolved iron species remaining in the WPA of decreased iron content is reduced. 6. A process for extracting uranium from the wet process phosphoric acid (WPA), the process comprising: (a) contacting WPA loaded with uranium with a first ion exchange resin to form WPA lacking uranium; (b) separating the WPA lacking uranium from the first ion exchange resin; (c) oxidizing the uranium species on the first ion exchange resin by contacting the first ion exchange resin with an oxidant; (d) contacting the first ion exchange resin with ammonia to remove the impurities from the resin, the impurities being vanadium ions, organic species or a combination thereof; (e) separating the impurities from the first ion exchange resin; (f) removing the oxidized uranium species from the first ion exchange resin by contacting the resin with ammonium carbonate to form a stream of ammonium carbonate enriched with uranium; (g) contact the ammonium carbonate stream enriched with uranium with a second ion exchange resin to form ammonium carbonate lacking uranium; (h) separating the ammonium carbonate lacking uranium from the second ion exchange resin; Y (i) eluting the uranium species from the second ion exchange resin to form an uranyl solution. 7. The process of claim 6, wherein the oxidant is selected from the group consisting of: air, oxygen, hydrogen peroxide, WPA and combinations thereof. 8. The process of claim 6, wherein the elution in step (i) is carried out using a solution comprising anions selected from the group consisting of: chloride anions, sulfate anions, nitrate anions and combinations thereof. 9. The process of claim 6, wherein step (a) is preceded by a valence reduction step comprising reducing the valence of ferric ions in the WPA. 10. The process of claim 9, wherein the step of valence reduction is preceded by a step of iron removal. eleven . The process of claim 6, wherein the uranyl solution is further treated to provide a product containing uranium. 12. The process of claim 1, wherein the additional treatment comprises a precipitation step. The process of claim 6, wherein step (a) is preceded by: decrease the amount of iron species dissolved in the WPA in relation to the amount of uranium species in the WPA to produce a WPA of decreased iron content having a uranium species in it; Y subjecting the WPA of decreased iron content to a reduction step, wherein the valence of dissolved iron species remaining in the WPA of decreased iron content is reduced. 14. A process for extracting uranium from wet process phosphoric acid (WPA), the process comprising: (a) contacting WPA loaded with uranium with an oxidant to form a stream of oxidized WPA; (b) contacting the oxidized WPA stream with an organic solvent; (c) separating a stream of organic solvent enriched with uranium from an aqueous WPA stream; (d) contacting the organic solvent stream enriched with uranium with a stream of ammonium carbonate to form a stream of ammonium carbonate enriched with uranium; (e) contacting the ammonium carbonate stream enriched with uranium with an ion exchange resin; (f) separating a current of ammonium carbonate lacking uranium from the ion exchange resin; (g) contacting the ion exchange resin with a solution comprising chloride ions; Y (h) separating a solution of uranyl from the resin of ion exchange 5. The process of claim 14, wherein the organic solvent comprises di (2-ethylhexyl) phosphoric acid and trioctylphosphine oxide. 16. The process of claim 14, wherein step (a) is preceded by a step of iron removal. 17. The process of claim 14, wherein the uranyl solution is further treated to provide a product containing uranium. 18. The process of claim 17, wherein the additional treatment comprises a precipitation step. 19. The process of claim 14, wherein step (a) is preceded by: decrease the amount of iron species dissolved in the WPA in relation to the amount of uranium species in the WPA to produce a WPA of decreased iron content having a uranium species in it; Y subjecting the WPA of decreased iron content to a reduction step, wherein the valence of dissolved iron species remaining in the WPA of decreased iron content is reduced. SUMMARY In a preferred embodiment, a process for extracting uranium from wet process phosphoric acid (WPA) comprises removing uranium from the WPA to produce a uranium-loaded solution stream and a WPA stream devoid of uranium. The uranium-charged solution stream is then contacted with an ion exchange resin. The uranium species bound to the ion exchange resin are eluted by contacting the resin with a solution comprising anions to produce an eluent stream charged with uranium. The eluent stream loaded with uranium is treated to provide a product containing uranium.