Uranium recovery from uranyl nitrate solution

Abstract

A method for recovering useful metals from a nitrate solution of a metal cation or a metal oxide cation is carried out by dropping the nitrate solution from the inlet of a production column. The production column contains a circulating solution containing a base selected from any one of ammonia, ammonium hydroxide, an alkali metal hydroxide, and an alkaline earth metal hydroxide. The nitrate reacts with the base in the circulating solution and precipitates as a metal oxide salt or a metal hydroxide salt. The precipitate and the circulating solution are discharged from the outlet nozzle of the production column, the precipitate is collected by a basket disposed below the production column, and the circulating solution is recovered in a recovery tank disposed below the basket. The recovered circulating solution is pumped back from the recovery tank to the production column. The nitrate of the metal cation may be, for example, the nitrate of a radioactive metal cation such as uranium or uranyl cation.

Description

[Technical Field]

[0001] Various examples disclosed herein relate to recovering radioactive metals, such as uranium, as ceramics from raw materials for forming uranium oxide gel particles, such as uranyl nitrate particles. [Background technology]

[0002] Metal nitrates are useful precursors for metal oxides prepared by the sol-gel method, and the metals include main group metals (e.g., lead), transition metals (e.g., yttrium, iron, zirconium), or lanthanide metals.

[0003] For example, iron oxide is prepared by heating the product of a sol-gel reaction between iron(III) nitrate and ethylene glycol. Depending on the conditions, maghemite and / or hematite may be produced from iron(III) nitrate. Lead zirconate titanate (PZT) powder can be prepared by the sol-gel method using lead nitrate, zirconium nitrate, and tetrabutyl titanate as precursors. Yttrium oxide can be prepared by the sol-gel method using yttrium nitrate as a precursor.

[0004] Nitrate precursors can also be used to prepare oxides of radioactive metals. Uranyl nitrate is a water-soluble uranium compound and is useful for producing uranium oxide nuclei in nuclear fuel applications. Plutonium and thorium oxides are also used in the nuclear energy field and can be prepared from their corresponding nitrates by the sol-gel process. Radioactive metal oxide gel particles can be prepared using a uranyl nitrate solution containing hexamethylenetetramine (HMTA) and urea. UO2((NH2)2CO)2 +2 A metal ion-urea complex is formed early, and the urea may help to suppress premature gelation. This solution is then heated to a temperature sufficient to cause HMTA decomposition. When the metal ion-urea complex is heated, UO2 +2Alternatively, they may dissociate to form similar uranium oxides. The metal ions undergo hydrolysis and condensation as in reactions (1) and (2).

[0005] (UO2) +2 (aq) +2H2O→(UO2(OH)2) (aq) +2H + (1) 2(UO2(OH)2) (aq) →2UO3·2H2O (2)

[0006] Simultaneously, HMTA decomposes to produce ammonium hydroxide. The ammonium hydroxide increases the pH of the solution, promoting hydrolysis and condensation, leading to the formation of metal ion particles 2UO3·2H2O as spherical gel particles. These uranium oxide gel spheres are collected and sintered to form ceramic particles useful as nuclei for nuclear fuel pellets.

[0007] Uranyl nitrate waste is regulated as hazardous radioactive waste. Therefore, uranyl nitrate waste or discarded material cannot be easily disposed of. Radioactive uranium can be recovered from uranyl nitrate solutions by generating insoluble uranates using a base. For example, ammonium diuranate is produced when uranyl nitrate is reacted with ammonia or ammonium hydroxide.

[0008] When handling ammonium diuranate (ADU) precipitate, the viscosity of the solid presents challenges in material handling. Moving raw ADU between containers results in large amounts of material remaining, making cleaning difficult and leading to material waste and losses.

[0009] Given the current need for an improved method for recovering uranium from uranyl nitrate solutions of waste materials, a brief overview of various embodiments is presented. While some simplifications and omissions may be made in this overview, these are intended to highlight and illustrate certain aspects of the subject matter disclosed herein and are not intended to limit the scope of the invention. Subsequent sections provide detailed descriptions of specific embodiments to enable those skilled in the art to formulate and utilize the concepts of the invention.

[0010] When metal oxides are produced by a sol-gel reaction using metal nitrates, unreacted nitrates often remain in the supernatant after the oxide gel is produced. Such unreacted metal nitrates, especially those containing heavy metals and / or radioactive metals, cannot be easily disposed of. These nitrates are environmental pollutants and may be toxic to humans and animals exposed to them. This disclosure relates to a method for recovering and reusing metals from waste metal nitrate solutions.

[0011] The various embodiments disclosed herein relate to the recovery of uranium from uranyl nitrate solutions, but the disclosed processes are not limited in particular to uranium or radioactive metals in general. The disclosed methods can be generalized to the recovery of metals from solutions of nitrates of metal cations or metal oxycations.

[0012] One general embodiment disclosed herein includes a method for recovering a useful metal from a solution of a nitrate of a metal cation or metal oxycation. This method includes adding a solution of nitrate to a generating column having inlet and outlet nozzles, the nitrate solution being added dropwise through the inlet, and the generating column containing a circulating solution containing a base selected from the group including ammonia, ammonium hydroxide, alkali metal hydroxides, and alkaline earth metal hydroxides. This method also includes reacting the nitrate in the solution with the base in the circulating solution to produce a metal oxide salt or metal hydroxide salt as a precipitate. The precipitate and circulating solution are discharged from the generating column through the outlet nozzle, the precipitate is collected in a basket located below the generating column, the circulating solution is collected in a recovery tank located below the basket, and the recovered circulating solution is pumped from the recovery tank to the generating column.

[0013] Embodiments may include one or more of the following features. In various embodiments, the nitrate is a salt of the following cation or oxycation: it is a transition metal (e.g., iron, zirconium, or titanium), a lanthanide metal (e.g., cerium), or an actinide metal (e.g., uranium, thorium, or plutonium).

[0014] In the various embodiments disclosed herein, the nitrate is uranyl nitrate, thorium nitrate, or plutonium nitrate. When the nitrate is uranyl nitrate, the base is ammonia or ammonium hydroxide, and the precipitate is ammonium diuranate.

[0015] In various embodiments, the precipitate is held in a basket during the washing and drying process. This method may include transferring the basket containing the collected precipitate from below the production column to an oxidation furnace, and heating the basket containing the collected precipitate in the oxidation furnace to convert the precipitate into a metal oxide.

[0016] One common embodiment includes a system for recovering useful metals from nitrate solutions of metal cations or metal oxycations. This system also includes: a generating column having inlet and outlet nozzles, the inlet of which is configured to drop a nitrate solution into the generating column; a basket located below the outlet nozzle; a recovery tank located below the basket; and a circulation system. The circulation system may include a first pump and a flow path between the recovery tank and the generating column. The first pump is configured to pump a circulating solution containing a base from the recovery tank to the generating column. The recovery tank is configured to receive the circulating solution from the generating column.

[0017] In various embodiments, the generating column is configured to produce a metal oxide salt as a precipitate when a base in the circulating solution reacts with a nitrate solution, and the outlet nozzle is configured to allow the circulating solution and precipitate to exit the generating column. A basket is configured to collect the precipitate while allowing the circulating solution to flow into a recovery tank.

[0018] Various embodiments describe a method for recovering uranium from a uranyl nitrate solution, which is carried out by dropwise addition of the uranyl nitrate solution to a production column having inlet and outlet nozzles. This production column contains a circulating solution containing a base, which is ammonia, ammonium hydroxide, alkali metal hydroxide, or alkaline earth metal hydroxide. The uranyl nitrate solution reacts with the base in the circulating solution to produce a diuranate precipitate. This precipitate and the circulating solution are discharged through the outlet nozzle of the production column, with the precipitate being collected in a basket below the production column, while the circulating solution is recovered in a recovery tank located below the basket. The recovered circulating solution is pumped from the recovery tank to the production column.

[0019] In various embodiments, the base is ammonia or ammonium hydroxide, and the precipitate is ammonium diuranate. The base may also be ammonium hydroxide.

[0020] The base may be an alkali metal hydroxide, and the precipitate may be an alkali metal diuranate.

[0021] This method may further include the steps of washing the diuranate precipitate with an aqueous washing solution and drying the washed precipitate. The precipitate may be held in a basket during the washing and drying steps.

[0022] This method may include the step of moving a basket containing the collected precipitate from below the production column to an oxidation furnace. Next, the basket containing the collected precipitate can be heated in the oxidation furnace to convert the precipitate to uranium oxide. The uranium oxide may be UO2, U2O5, UO3, U3O8, UO2O2, or a mixture thereof.

[0023] Various embodiments disclosed herein relate to a system for recovering uranium from a uranyl nitrate solution. The system includes: a production column having an inlet and an outlet nozzle, the production column configured such that the inlet drips the uranyl nitrate solution into the production column; a basket disposed below the outlet nozzle; a recovery tank disposed below the basket; a first pump; and a flow path between the recovery tank and the production column, which is a circulation system.

[0024] The first pump is configured to pump a circulation solution containing a base from the recovery tank to the production column, and the recovery tank is configured to receive the circulation solution from the production column. The production column is configured such that the base in the circulation solution reacts with the uranyl nitrate solution to produce diuranate as a precipitate. The outlet nozzle is configured such that the circulation solution and the precipitate can exit the production column. The basket is configured to collect the precipitate and allow the circulation solution to flow into the recovery tank.

[0025] A system for recovering uranium from a uranyl nitrate solution can also include a washing station, a wash liquor discharge port, a wash tank below the wash liquor discharge port, a second pump, and means for moving a basket containing the collected precipitate from below the outlet nozzle of the production column to the washing station. In various embodiments, the second pump is configured to pump wash liquor from the wash tank to the wash liquor discharge port to generate a flow of wash liquor. The moving means is configured to place the basket below the wash liquor discharge port such that the collected precipitate is washed by the flow of wash liquor.

[0026] A system for recovering uranium from a uranyl nitrate solution can also include an oxidation furnace and means for moving a basket containing the washed precipitate from the washing station to the oxidation furnace. The oxidation furnace is configured to convert the precipitate to uranium oxide.

[0027] As described above, the methods and apparatus disclosed herein are not limited to common radioactive metals or particularly uranium. Various embodiments relate to methods for recovering metals from metal nitrate solutions, which are performed by adding the metal nitrate solution dropwise to a production column having inlet and outlet nozzles. The production column contains a circulating solution containing a base that is ammonia, ammonium hydroxide, an alkali metal hydroxide, or an alkaline earth metal hydroxide. The metal nitrate solution reacts with the base in the circulating solution to produce a metal oxide salt or a metal hydroxide salt as a precipitate. The precipitate and the circulating solution are discharged through the outlet nozzle of the production column, the precipitate is collected in a basket disposed below the production column, while the circulating solution is recovered in a recovery tank disposed below the basket. The recovered circulating solution is pumped from the recovery tank to the production column. In various embodiments, the nitrate is a transition metal nitrate such as iron(III) nitrate or yttrium(III) nitrate. When using iron(III) nitrate as a precursor, the base in the circulating solution is ammonium hydroxide and the precipitate is iron(III) hydroxide. Iron(III) hydroxide is converted to iron oxide in a furnace.

[0028] In various embodiments, the nitrate is a lanthanide metal nitrate such as cerium(III) nitrate. When cerium(III) nitrate is used as the precursor, the base in the circulating solution is ammonium hydroxide, and the precipitate is cerium(III) hydroxide. The cerium(III) hydroxide is converted to yttrium oxide in the furnace. [Brief explanation of the drawing]

[0029] Refer to the attached drawings for a better understanding of the various exemplary embodiments. [Figure 1] Figure 1 shows a system for recovering uranium from a uranyl nitrate solution of waste material, and includes a production column for precipitation of diuranate. [Figure 2] Figure 2 shows a basket for collecting the precipitated biuranate. [Figure 3] Figure 3 shows a system for recovering diuranate from a uranyl nitrate solution of waste material and oxidizing the diuranate to convert it into uranium oxide. [Modes for carrying out the invention]

[0030] In this disclosure, metal oxide salt precipitates will be understood to include metal oxide salts, metal hydroxide salts, mixtures thereof, or precipitates of metal oxide salts having hydroxide ligands.

[0031] The systems and methods disclosed herein are useful for recovering the metal value from solutions of metal nitrates used as precursors in the synthesis of metal oxides. When unreacted metal nitrates remain after the synthesis of a desired oxide, it is economically undesirable to discard such nitrates. It is preferable to recover the metal value from the nitrate solution and either directly convert the metal into the desired product or recycle the metal for reuse.

[0032] Furthermore, many oxides are made from toxic heavy metals or radioactive metals. When performing sol-gel reactions to produce metal oxides using metal nitrates, unreacted nitrates commonly remain in the supernatant after the oxide gel is formed. Such unreacted metal nitrates cannot be easily disposed of, especially when heavy metals and / or radioactive metals are involved. These nitrates are environmental pollutants and can be harmful to humans and animals to which they are exposed. Even if the metal itself or the metal nitrate itself is not considered harmful, it may undergo chemical changes and produce harmful compounds when released into the environment. Therefore, waste liquids containing metal nitrates cannot be released into the environment. This disclosure relates to a method for recovering and reusing metals from waste metal nitrate solutions.

[0033] A method for recovering useful metals from a nitrate solution of a metal cation or metal oxycation may include the following steps: adding the nitrate solution dropwise to a generating column having inlet and outlet nozzles; the generating column containing a circulating solution containing a base selected from the group consisting of ammonia, ammonium hydroxide, alkali metal hydroxides, and alkaline earth metal hydroxides; reacting the nitrate in the nitrate solution with the base in the circulating solution to produce a metal oxide salt or metal hydroxide salt as a precipitate; discharging the precipitate and circulating solution through the outlet nozzle of the generating column; recovering the circulating solution in a recovery tank located below the basket while collecting the precipitate in a basket located below the generating column; and pumping the recovered circulating solution from the recovery tank to the generating column. Referring here to the drawings, similar numbers indicate similar components or steps, and a wide range of exemplary embodiments are disclosed.

[0034] Figure 1 shows a system for recovering useful metals from a solution of nitrates of metal cations or metal oxycations. The system includes a recovery station 100. The recovery station 100 has a generating column 1 having an inlet 3 and an outlet nozzle 2. The inlet 3 carries the nitrate solution to the generating column 1, and the nitrate solution is dripped into the generating column 1 via the inlet 3. The generating column 1 contains a circulating solution containing a base. The nitrate in the nitrate solution reacts with the base in the circulating solution to produce an oxide salt or metal hydroxide salt as a precipitate. The precipitate and circulating solution exit the generating column 1 through the outlet nozzle 2, the precipitate is collected in a basket 5 below the generating column 1, and the circulating solution is collected in a recovery tank 6 below the basket 5. The recovered circulating solution is pumped from the recovery tank 6 to the generating column 1 by a pump 4.

[0035] In various embodiments, the generating column contains a circulating solution comprising ammonia, ammonium hydroxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, or magnesium hydroxide as a base.

[0036] The generating column may contain a circulating solution containing ammonia or ammonium hydroxide as a base. The base reacts with the oxide salt or metal hydroxide salt to precipitate the metal oxide salt or metal hydroxide salt.

[0037] In various embodiments, the nitrate solution contains the following nitrates: cations or oxycations of main group metals (e.g., group 2 metals such as magnesium or calcium, group 13 metals such as gallium or indium, group 14 metals such as tin or lead, group 15 metals such as bismuth, or group 16 metals such as tellurium), cations or oxycations of transition metals (e.g., yttrium, zirconium, zinc, or iron), cations or oxycations of lanthanide metals (e.g., cerium), or cations or oxycations of actinide metals (e.g., thorium, uranium, or plutonium).

[0038] In various embodiments, the nitrate is iron(III) nitrate. The production column contains a circulating solution that includes ammonium hydroxide as a base, and the base reacts with the iron(III) nitrate salt to precipitate iron(III) hydroxide.

[0039] In various embodiments, the nitrate is yttrium(III) nitrate. The production column contains a circulating solution that includes ammonium hydroxide as a base, and the base reacts with the yttrium(III) nitrate salt to precipitate yttrium(III) hydroxide.

[0040] In various embodiments, the nitrate is a nitrate of a radioactive metal cation or oxycation, such as uranyl nitrate, thorium nitrate, or plutonium nitrate. The production column can contain a circulating solution that includes an alkali metal hydroxide, an alkaline earth metal hydroxide, an ammonium hydroxide salt, or ammonia as a base. The base reacts with the nitrate to precipitate a salt of the radioactive metal cation or oxycation.

[0041] In various embodiments, the nitrate is uranyl nitrate, and the production column may contain a circulating solution that includes an ammonium hydroxide salt or ammonia as a base. The base reacts with uranyl nitrate to precipitate an ammonium diuranate salt of the formula (NH4)2U2O7.

[0042] In various embodiments, the nitrate is uranyl nitrate, and the production column may contain a circulating solution that includes an alkali metal hydroxide M 1 OH as a base. The base reacts with uranyl nitrate to precipitate an alkali metal diuranate salt of the formula M 1 2U2O7.

[0043] In various embodiments, the nitrate is uranyl nitrate, and the production column may contain a circulating solution that includes an alkaline earth metal hydroxide M 2 (OH)2 as a base. The base reacts with uranyl nitrate to precipitate an alkaline earth metal diuranate salt of the formula M 2 U2O7.

[0044] The following discussion focuses on the recovery of uranium from uranyl nitrate solutions. In the uranium recovery system shown in Figure 1, uranium is recovered from nitrate solutions of metal cations or metal oxycations. This system includes a recovery station 100. The recovery station 100 has a product column 1 having an inlet 3 and an outlet nozzle 2. The inlet 3 carries the uranyl nitrate solution to the product column 1, which is dropped into the product column 1 through the inlet 3. The product column 1 contains a circulating solution containing a base. The uranyl nitrate in the uranyl nitrate solution reacts with the base in the circulating solution to produce a diuranate precipitate. For example, if the base is ammonium hydroxide or ammonia, ammonium diuranate is obtained as a precipitate. The ammonium diuranate precipitate and the circulating solution are discharged from the product column through the outlet nozzle 2, the precipitate is collected in a basket 5 located below the product column 1, and the circulating solution is recovered in a recovery tank 6 located below the basket 5. The recovered circulating solution is then sent from the recovery tank 6 to the generation column 1 by the pump 4.

[0045] In embodiments where the nitrate is a nitrate of a radioactive metal cation or oxycation, it is desirable to prepare a production column 1 with an outer diameter of 4.5 inches or less, 4 inches or less, 3 inches or less, or 2 to 4.5 inches to avoid critical events. In embodiments where the nitrate is a nitrate of a non-radioactive metal cation production column 1, a larger diameter may be used if desired.

[0046] The recovery system shown in Figure 1 may include a washing station 200. The basket 5 containing the recovered sediment is transported to the washing station 200 and placed on top of the washing tank 7. The aqueous washing solution is circulated by a pump 8 from the washing tank 7 to an outlet at the top of the basket 5. The washing solution then passes through the basket 5, washing the sediment.

[0047] The boundaries of the recovery station 100 are defined by barriers 12 and 13. The boundaries of the washing station 200 are defined by barriers 13 and 14. As described later, the basket 5 can be suspended above the recovery tank 6 and / or washing tank 7 using rails or cables 15.

[0048] In various embodiments, the uranium recovery system may include a drying station 300. The basket 5 containing the washed precipitate is transported to the drying station 300 and suspended from a hook or loop 9 of a drying rack 10. The drying rack suspends the basket over a tray 11.

[0049] Once the sediment in the basket has dried, move basket 5 containing the dried sediment to the furnace.

[0050] As shown in Figure 2, the basket 5 includes a porous material 23 formed from a material stable at temperatures between 500°C and 800°C. Suitable materials include stainless steel, titanium, molybdenum, titanium-zirconium-molybdenum alloy, nickel, tantalum, tungsten, nickel, nickel-chromium alloy, and alloys thereof. The porous material 23 can be a wire mesh formed from a metal or metal alloy. In various embodiments, the porous material 23 may be a perforated metal sheet formed from a metal or metal alloy. The porous material 23 may be a fabric or mesh formed from carbon fibers, ceramic fibers, or yarns formed from such fibers.

[0051] Basket 5 contains a non-porous material 22 formed from metals that are stable at temperatures between 500°C and 800°C, such as stainless steel, titanium, molybdenum, titanium-zirconium-molybdenum alloy, nickel, tantalum, tungsten, nickel-chromium alloy, and alloys thereof. The non-porous material 22 adds rigidity to basket 5.

[0052] The basket 5 may include a top 21 with a hook or flange 21a. The hook or flange 21a may be configured to suspend the basket 5 above the recovery tank 6 and the washing tank 7 by hooking it onto a rail or cable 15 above the tanks 6 and 7. The hook or flange 21a may also be configured to suspend the basket 5 above the tray 11 by hooking it onto a hook or loop 9 of the drying rack 10.

[0053] Figure 3 shows a second embodiment of a system for recovering uranium from a uranyl nitrate solution. Oxygen-deficient uranyl nitrate flows from inlet 3 to production column 1, which may be a glass or metal tube bolted to a uranyl nitrate recovery housing 31. A basket 5 is located in or on top of the recovery tank 6. A pump 4 pumps a base solution (e.g., ammonium hydroxide solution) from the recovery tank 6 through conduit 32 and to production column 1 through conduit 33. A constant amount of base solution is maintained in production column 1 while the pump 4 is operating. Oxygen-deficient uranyl nitrate is dripped into production column 1 from inlet 3. The uranyl nitrate reacts with the base to produce insoluble diuranates, which flow out of a nozzle (shown in Figure 1) at the bottom of production column 1 along with the recirculating ammonium hydroxide solution. The insoluble diuranates are collected in basket 5, and the ammonium hydroxide solution flows into the recovery tank 6 and is then pumped back into production column 1.

[0054] Basket 5 is then moved to a position inside or above the washing tank 7. The washing solution is sent by pump 8 through conduit 34 to an outlet at the top of basket 5. The washing solution flows through basket 5 into washing tank 7. The liquid in washing tank 7 flows through conduit 35 to pump 8 and is circulated back to washing tank through conduit 34. After washing, the washed basket 5 and its contents (diuranate) are moved to a drying station and stored on tray 11 until the diuranate is dry.

[0055] The contents of basket 5 and its dried diuranate are transferred to a recovery oxidation furnace 37. The recovery oxidation furnace 37 may be heated in various ways. The recovery oxidation furnace 37 may have resistance-heatable graphite walls. The recovery oxidation furnace 37 may be heated by conductive coils. The recovery oxidation furnace 37 may be heated by a high-temperature vertical tube furnace 36. The vertical tube furnace 36 may be fitted with ceramic heater elements, such as molybdenum silicide (MoSi2) heater elements. The vertical tube furnace 36 can reach temperatures of up to 1800°C.

[0056] The precipitate is oxidized in an oxidation furnace. When this system converts a transition metal nitrate (e.g., iron(III) nitrate) to a transition metal oxide or transition metal hydroxide (e.g., iron(III) hydroxide) to recover the transition metal, it is heated to produce the oxide (e.g., iron(III) oxide). Similar procedures can be applied to other actinide metal nitrates, lanthanide metal nitrates, and transition metal nitrates. For example, zirconium oxynitrate (ZrO(NO3)2), cerium nitrate (Ce(NO3)3), and yttrium nitrate (Υ(NO3)3) can be converted to oxides by reacting them with ammonia or ammonium hydroxide to produce a precipitate, which is then heated using the system shown in Figure 1 and / or Figure 2.

[0057] If basket 5 contains ammonium diuranate, the temperature of the recovery oxidation furnace 37 is controlled based on the desired final uranium oxide result. When ammonium diuranate [(NH4)2U2O7] is heated from approximately 420°C to 550°C, the compound undergoes denitrification and conversion to UO3. When ammonium diuranate is heated from approximately 550°C to 850°C, the compound is converted to an oxide with approximately the formula U3O8. However, such conversions occur under ideal conditions, and usually the final result is often a mixture or alloy of various uranium oxides such as UO2, U2O5, UO3, U3O8, UO2O2, or mixtures thereof. At temperatures above 900°C or above 1000°C, ammonium diuranate is converted to an oxide with approximately the formula U8O21 It may be converted into an oxide containing [a certain compound].

[0058] After the ammonium diuranate salt is converted to oxide ceramic in the recovery oxidation furnace 37, the basket 5 containing the uranium oxide ceramic is transferred to the glove box 38 for cooling. Once the basket 5 has cooled to an acceptable temperature, it is recovered through the pathway 41, and the contents of the uranium oxide are recovered.

[0059] While various embodiments are described in detail with particular relevance to specific aspects, it should be understood that the present invention is applicable to other embodiments as well, and its details can be modified in various obvious ways. As will be apparent to those skilled in the art, modifications and alterations can be made within the spirit and scope of the invention. Accordingly, the foregoing disclosures, descriptions, and figures are for illustrative purposes only and do not limit the invention in any way, and are defined solely by the claims.

Claims

1. A method for recovering useful metals from a solution of a nitrate of a metal cation or metal oxycation, A nitrate solution is added dropwise from the inlet to a generating column having an inlet and an outlet nozzle. The generating column comprises a circulating solution containing a base selected from the group consisting of ammonia, ammonium hydroxide, alkali metal hydroxides, and alkaline earth metal hydroxides. The nitrate in the nitrate solution is reacted with the base in the circulating solution to produce a precipitate as a metal oxide salt or metal hydroxide salt. The precipitate and the circulating solution are made to exit the generating column through the outlet nozzle, The precipitate is collected in a basket located below the generation column, and the circulating solution is collected in a recovery tank located below the basket. The recovered circulating solution is pumped from the recovery tank to the generation column. A method that includes the act of doing so.

2. The method according to claim 1, wherein the nitrate is a salt of a cation or oxycation of a main group metal, a transition metal, a lanthanide metal, or an actinide metal.

3. The method according to claim 1, wherein the nitrate is uranyl nitrate, thorium nitrate, or plutonium nitrate.

4. The nitrate is uranyl nitrate, The base is ammonia or ammonium hydroxide, The precipitate is ammonium diuranate. The method according to claim 3.

5. The method according to claim 4, wherein the base is ammonium hydroxide.

6. The method according to claim 3, wherein the nitrate is uranyl nitrate, the base is an alkali metal hydroxide, and the precipitate is an alkali metal diuraneate.

7. Further wash the precipitate with an aqueous washing solution. The washed precipitate is dried, Here, the precipitate is held in a basket during the washing and drying process. The method according to claim 1.

8. A method for recovering a useful metal from a solution of a nitrate of a metal cation or a metal oxycation, A nitrate solution is added dropwise from the inlet to a generating column having an inlet and an outlet nozzle. The generating column comprises a circulating solution containing a base selected from the group consisting of ammonia, ammonium hydroxide, alkali metal hydroxides, and alkaline earth metal hydroxides. The nitrate in the nitrate solution is reacted with the base in the circulating solution to produce a precipitate as a metal oxide salt or metal hydroxide salt. The precipitate and the circulating solution are made to exit the generating column through the outlet nozzle, The precipitate is collected in a basket located below the generation column, and the circulating solution is collected in a recovery tank located below the basket. The recovered circulating solution is pumped from the recovery tank to the generation column. The above method further, The basket containing the collected precipitate is then moved from below the production column to the oxidation furnace, and The basket containing the collected precipitate is heated in an oxidation furnace to convert the precipitate into a metal oxide. A method that includes the act of doing so.

9. The aforementioned nitrate is uranyl nitrate, The base is ammonia or ammonium hydroxide. The aforementioned precipitate is ammonium diuranate, The aforementioned metal oxide is UO ２ , U ２ O ５ , UO ３ , U ３ O ８ , UO ２ O ２ , or a mixture thereof The method according to claim 8.

10. The nitrate is iron(III) nitrate. The method according to claim 1.

11. The aforementioned base is ammonium hydroxide. The precipitate is iron(III) hydroxide. The method according to claim 10.

12. The nitrate is yttrium(III) nitrate or cerium(III) nitrate. The method according to claim 1.

13. The aforementioned base is ammonium hydroxide, The precipitate is yttrium(III) hydroxide or cerium(III) hydroxide. The method according to claim 12.

14. A system for recovering useful metals from a solution of nitrates of metal cations or metal oxycations, A production column having an inlet and an outlet nozzle, wherein the inlet is configured to drop a nitrate solution into the production column, A basket positioned below the outlet nozzle, A recovery tank located below the basket, and A recirculation system comprising a first pump and a flow path between the recovery tank and the generation column, The first pump is configured to pump the circulating solution containing the base from the recovery tank to the production column. The recovery tank is configured to receive the circulating solution from the generation column, The generation column is configured such that the base in the circulating solution reacts with the nitrate solution to produce a metal oxide salt as a precipitate. The outlet nozzle is configured such that the circulating solution and the precipitate exit the production column. The basket is configured to collect the sediment, and the circulating solution flows into the recovery tank. The aforementioned system further, Oxidizing furnace and The means for transporting the basket containing the collected precipitate into the oxidation furnace, The oxidation furnace is configured to convert the precipitate into a metal oxide. system.

15. The system according to claim 14, wherein the nitrate is uranyl nitrate, thorium nitrate, or plutonium nitrate.

16. The nitrate is uranyl nitrate, the base is ammonia or ammonium hydroxide, and the precipitate is ammonium diuranate. The system according to claim 15.

17. Washing station and Cleaning fluid outlet, A cleaning tank located below the cleaning liquid outlet, The second pump, and The system includes means for transporting the basket containing the collected sediment from below the outlet nozzle to the washing station, Here, The second pump is configured to pump the cleaning liquid from the cleaning tank to the cleaning liquid outlet in order to generate a flow of cleaning liquid. The means for transporting the material is configured such that the basket is positioned below the washing liquid outlet so that the collected sediment is washed by the flow of the washing liquid. The system according to claim 14.

18. The aforementioned nitrate is uranyl nitrate, The base is ammonia or ammonium hydroxide. The aforementioned precipitate is ammonium diuranate, The oxidation furnace is configured to convert the precipitate into uranium oxide. The system according to claim 14.

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