Isotope separation of lithium

Abstract

The present disclosure relates to a method for isotopic separation of lithium, the method comprising the steps of: providing a first mixture (104) comprising at least lithium, lithium hydride and possibly lithium deuteride and / or lithium tritide, the first mixture being at a first temperature; a first cooling step (110), preferably homogeneous cooling, adapted to cool the first mixture to a second temperature lower than the first temperature, and adapted to precipitate a first portion of the lithium hydride having the first lithium isotope; a first separation step (124) adapted to separate a first portion of the precipitated lithium hydride from the first mixture to form a second mixture (122).

Description

[0001] This application is based on and claims the priority of European Patent Application No. 22305449 filed on April 4, 2022, entitled “Isotope Separation of Lithium” and European Patent Application No. 22305438 filed on April 4, 2022, entitled “Device and Method for Extracting Lithium Hydride”, which are incorporated herein by reference to the maximum extent permitted by law. Technical Field

[0002] The present application discloses a method for isotope separation of lithium isotopes. In particular, the disclosed method relates to separation of lithium isotopes in a fluid medium based on phase transition temperature difference. Background Art

[0003] The industry needs to separate isotopes, mainly to separate lighter isotopes from elements. In nuclear energy applications (including fusion and fission), it is necessary to separate the isotopes of lithium found in nature, namely lithium-6 ( 6 Li) and lithium-7( 7 Natural lithium contains 7.4% 6 Li and 92.6% 7 Li.

[0004] In nuclear fusion power generation, lithium is used to produce tritium, which is the main fuel for fusion generators. However, the most common isotope of lithium is 7 Li is a poor breeder of tritium due to its small cross section, so it is desirable to use 6 Li acts as a breeding blanket for tritium. Since this isotope is quite uncommon, lithium needs to be concentrated. 6 The concentration of Li is increased. In a solid breeder reactor, the concentration may have to be increased to between 30% and 60%; however, in a liquid breeder reactor, the concentration may have to be as high as 90%.

[0005] Lithium enrichment is useful in other applications. In generators that use the principle of nuclear fission, lithium with a purity of about 99% 7 Li is used as a neutron absorber, to control acidity and neutron moderation, and as a coolant in molten salt reactors.

[0006] The demand for lithium concentrate is increasing due to 6 Lithium-ion batteries work more efficiently, and as fusion reactors become a reality, the demand for this is expected to increase even more in the coming years.

[0007] Currently, concentrated lithium is supplied from stockpiles produced in the United States between the 1950s and 1970s using the expensive COLEX process. 6The market price of lithium is about $500 per 10 grams, a prohibitive cost considering that the amount of concentrated lithium required for each gigawatt of energy in a fusion power plant is about 60 tons.

[0008] Currently, there seems to be no way to produce the concentrated lithium in the quantities needed for fusion power plants. Beyond that, the methods that have been developed have two problems: they are very expensive and they are very polluting to the environment.

[0009] Concentrated lithium is mainly produced by three methods: COLEX, OREX and ELEX. COLEX and OREX are chemical exchange processes based on countercurrent flow of LiOH or LiCl solution and lithium amalgam. The concentrated lithium is deposited on the amalgam phase. Methods based on the electrical properties of lithium are also used. In the ELEX method, a lithium salt solution is electrolyzed in countercurrent flow using a mercury cathode.

[0010] In particular, the above methods utilize mercury to some extent. These methods were widely used in the United States to produce lithium between the 1950s and 1980s. The COLEX process alone used about 24 million pounds of mercury. Although most of the mercury was properly disposed of, about 2 million pounds of mercury remained unaccounted for. The unaccounted mercury may have entered the environment and may be the cause of mercury contamination in several water bodies in eastern Virginia.

[0011] The current trend in lithium ion separation or enrichment involves laser separation and electromagnetic separation. These methods are expensive and slow and require very special materials and equipment. Dr. Thomas Giegerich, chief engineer in the vacuum system development department at DEMO, points out the limitations of these methods. Writing in "Lithium Enrichment Issues in a Sustainable Supply Chain for Future Fusion Reactors" published on www.kit.edu, Dr. Thomas Giegerich recommends further development of mercury-based methods because the classic COLEX-related methods have the highest quality values ​​at the lowest development effort.

[0012] In U.S. Pat. No. 8,672,138 to Raizen et al., a vapor of several atoms of a single element is formed into a stream and then light waves are applied. The light waves are tuned to prepare a specific isotope to a specific magnetic state. A magnetic field is then applied to separate the isotopes according to their magnetic state. The method described is apparently based on laser methods and electromagnetic methods that exploit these properties of the isotopes. Methods like the one described by Raizen are not suitable for lithium applications. They are unsuitable because lithium isotopes in fusion reactors must be separated as part of the power plant process. Since the elements must be vaporized, it is not easy to combine this method with fusion reactor processes, where lithium can be either liquid or solid. A major problem with Raizen's method is that the operating temperature of the fusion process may not allow every part of the method to be effective. In addition, the method may be too slow to accommodate the speeds required for fusion reactors. And, since the light wave equipment required for the method may require very specific temperatures as well as expensive components to work, it is not a very suitable method for lithium enrichment that a fusion power plant can rely on.

[0013] Another laser-based approach is described in U.S. Pat. No. 4,149,077 to Yamashita et al. According to Yamashita, a laser separates lithium isotopes by irradiating a beam of lithium atoms with a beam tuned to the absorption line of an arbitrary lithium isotope. This causes the isotope to ionize, which is then separated by a mass filter (e.g., a magnetic field-based mass spectrometer). This approach requires the lithium to be in a very specific state to work, which in this case is a beam of lithium atoms. To use this approach in a fusion power plant, the working lithium would need to be removed from the process, processed, and then reinserted. This can result in additional heat losses that may not be easy to overcome depending on the configuration of the power plant. Furthermore, the process may need to be stopped to prepare the lithium before the separation is achieved, so this is not a method that works properly as part of a fusion power plant sequence.

[0014] Processes based on the electromagnetic properties of isotopes and laser methods are also difficult and costly to scale up because they are either surface effects or volume effects of atomic or ion beams, which are necessarily in a gaseous or plasma state and therefore generally have a lower density than liquids and solids. These processes are also energy inefficient, which increases the overall cost of the process. Considering that experts in the field point out that current trends are limited to chemical separation methods like COLEX using mercury and methods that exploit the electromagnetic properties of lithium isotopes, there is a need for lithium isotope separation methods that are reliable, cheap, fast, environmentally friendly, and can work in conjunction with fusion reactor processes. Summary of the invention

[0015] One embodiment overcomes all or part of the disadvantages of known methods for isotope separation of lithium.

[0016] One embodiment provides a method for isotope separation of lithium, the method comprising:

[0017] - providing a first mixture comprising at least lithium, lithium hydride and possibly lithium deuteride and / or lithium tritide, the first mixture being at a first temperature;

[0018] a first cooling step, the first cooling step preferably being a uniform cooling step, the first cooling step being adapted to cool the first mixture to a second temperature lower than the first temperature, and the first cooling step being adapted to precipitate a first portion of lithium hydride having a first lithium isotope; and

[0019] - a first separation step suitable for separating a first portion of the precipitated lithium hydride from the first mixture to form a second mixture.

[0020] In one embodiment, the method further comprises a first extraction step adapted to extract a first portion of the precipitated lithium hydride after or during the first separation step.

[0021] In one embodiment, the method further comprises:

[0022] a second cooling step, which is preferably a uniform cooling step, which is suitable for cooling the second mixture to a third temperature lower than the second temperature, and which is suitable for precipitating a second portion of lithium hydride having a second lithium isotope; and

[0023] - a second separation step suitable for separating a second portion of the precipitated lithium hydride from the second mixture to form a third mixture.

[0024] In one embodiment, the method further comprises a second extraction step adapted to extract a second portion of the precipitated lithium hydride after or during the second separation step.

[0025] In one embodiment, the first cooling step and / or the second cooling step is slow, for example having a cooling rate of less than 1°C per minute.

[0026] In one embodiment, providing the first mixture comprises a heating step, the heating step being adapted to heat the first mixture to a first temperature.

[0027] In one embodiment, the method comprises repeating the providing step and repeating the following steps:

[0028] - a first cooling step and a first separation step, at least part of the second mixture being used as the first mixture; and / or

[0029] - a second cooling step and a second separation step, at least part of the third mixture being used as the first mixture.

[0030] In one embodiment, the first isotope is 7 Li isotope, the second isotope is 6 Li isotopes.

[0031] In one embodiment:

[0032] - the first temperature is above about 410° C., for example above about 500° C.;

[0033] - the second temperature is between 390° C. and 410° C., for example approximately equal to 400° C.; and / or

[0034] The third temperature is between 388°C and 408°C, for example approximately equal to 398°C.

[0035] In one embodiment, at least one of the first separation step and the second separation step comprises rotating the first mixture and / or the second mixture, for example rotating a chamber containing said mixture.

[0036] One embodiment provides a method for isotope separation of lithium, the method comprising:

[0037] - providing a first mixture comprising at least lithium and lithium hydride, the first mixture being at a first temperature;

[0038] a first cooling step, the first cooling step preferably being a uniform cooling step, the first cooling step being adapted to cool the first mixture to a second temperature lower than the first temperature, and the first cooling step being adapted to precipitate a first portion of lithium hydride having a first lithium isotope;

[0039] - a first separation step, the first separation step being suitable for separating a first portion of the precipitated lithium hydride from the first mixture to form a second mixture; and

[0040] - a first extraction step, the first extraction step being suitable for extracting a first portion of the separated lithium hydride after or during the first separation step.

[0041] In one embodiment, the first mixture further includes lithium deuteride and / or lithium tritide.

[0042] In one embodiment, the first cooling step is slow, for example, the first cooling step has a cooling rate of less than 1°C per minute.

[0043] In one embodiment, the method further comprises:

[0044] a second cooling step, the second cooling step preferably being a uniform cooling step, the second cooling step being adapted to cool the second mixture to a third temperature lower than the second temperature, and the second cooling step being adapted to precipitate a second portion of lithium hydride having a second lithium isotope;

[0045] - a second separation step, adapted to separate a second portion of the precipitated lithium hydride from the second mixture to form a third mixture; and

[0046] - a second extraction step, suitable for extracting a second portion of the separated lithium hydride after or during the second separation step.

[0047] In one embodiment, the second cooling step is slow, for example, the second cooling step has a cooling rate of less than 1°C per minute.

[0048] In one embodiment, providing the first mixture comprises a heating step, the heating step being adapted to heat the first mixture to a first temperature.

[0049] In one embodiment, the method comprises repeating the providing step and repeating the following steps:

[0050] - a first cooling step and a first separation step, at least part of the second mixture being used as the first mixture; and / or

[0051] - a second cooling step and a second separation step, at least part of the third mixture being used as the first mixture.

[0052] In one embodiment, the method comprises repeating the providing step and repeating the following steps:

[0053] - a first cooling step, a first separation step and a first extraction step, at least part of the second mixture being used as the first mixture; and / or

[0054] - a second cooling step, a second separation step and a second extraction step, at least part of the third mixture being used as the first mixture.

[0055] In one embodiment, the first isotope is 7 Li isotope, the second isotope is 6 Li isotopes.

[0056] In one embodiment:

[0057] - the first temperature is higher than 410° C., for example higher than 500° C.;

[0058] - the second temperature is lower than or equal to 410° C., for example between 390° C. and 410° C., for example approximately equal to 400° C.; and / or

[0059] - the third temperature is lower than or equal to 408°C, for example between 388°C and 408°C, for example approximately equal to 398°C.

[0060] In one embodiment, at least one of the first separation step and the second separation step comprises rotating the first mixture and / or the second mixture, such as rotating a chamber containing the first mixture and / or the second mixture.

[0061] In one embodiment, the first temperature and the second temperature are determined according to the concentration of lithium hydride in the first mixture.

[0062] In one embodiment, the third temperature is determined according to the concentration of lithium hydride in the first mixture.

[0063] In one embodiment, the first temperature and the second temperature are determined using a Li / LiH phase diagram.

[0064] In one embodiment, the third temperature is determined using a Li / LiH phase diagram.

[0065] In one embodiment, the molar concentration of lithium hydride in the first mixture is between 2% and 95%, such as between 2.5% and 95%.

[0066] In one embodiment, the second temperature and the third temperature are both greater than 200°C, such as greater than 210°C.

[0067] An embodiment provides a device, which is suitable for implementing the method according to the embodiment, wherein the device comprises:

[0068] - a chamber adapted to contain a mixture comprising at least lithium and lithium hydride; and

[0069] - Cooling means adapted to cool the mixture in the chamber.

[0070] In one embodiment, the cooling mechanism comprises a cooling jacket and means adapted to convey a coolant in the cooling jacket, the cooling jacket at least partially covering the chamber.

[0071] In one embodiment, the apparatus further comprises a heating device adapted to heat the mixture in the chamber, such as an ohmic heating device or an induction heating device.

[0072] In one embodiment, the apparatus further comprises a rotating device adapted to rotate the chamber, the rotating device being, for example, a shaft coupled to the chamber and to a motor located outside the chamber.

[0073] In one embodiment, the shape of the chamber enables liquid or solid matter accumulated at the bottom of the chamber to be discharged, and the shape of the chamber is, for example, a bell shape, an inverted bell shape, or a diamond shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The foregoing features and advantages, as well as other aspects, will be described in detail in the following description of specific embodiments given by way of example and not limitation, with reference to the accompanying drawings, in which:

[0075] Figure 1 is a diagram describing a method for isotope separation of lithium.

[0076] Figure 2 is a front view of an apparatus for performing a method for isotope separation of lithium.

[0077] Figure 3 It is the Li / LiH phase diagram based on the molar concentration of LiH.

[0078] Figure 4 is another Li / LiH phase diagram based on the molar concentration of LiH. DETAILED DESCRIPTION

[0079] In the various figures, similar features are indicated by similar reference numerals. In particular, common structural and / or functional features in various embodiments may have the same reference numerals and may exhibit the same structure, dimensions, and material properties.

[0080] For clarity, only the operations and elements that are helpful for understanding the embodiments described herein are shown and described in detail.

[0081] Unless otherwise specified, when referring to two elements being connected together, this means a direct connection without any intermediate elements other than conductors, and when referring to two elements being coupled together, this means the two elements may be connected or coupled through one or more other elements.

[0082] In the following disclosure, unless otherwise stated, when referring to absolute position qualifiers such as terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers such as terms "above", "below", "higher", "lower", etc., or orientation qualifiers such as "horizontal", "vertical", etc., reference is made to the orientation shown in the figure.

[0083] Unless otherwise indicated, expressions such as "about," "approximately," "substantially," and "on the order of" mean within 10%, preferably within 5%.

[0084] The drawings are not drawn to scale. It should be noted that the drawings relate to embodiments of the disclosed method and apparatus for isotope separation of lithium, sometimes also referred to as apparatus or method, respectively. As can be easily understood by a properly trained person, other embodiments are also possible. The actual size and / or shape of each component of the embodiment can be varied. Only the important details of the embodiment are shown, however, a person of ordinary skill in the art can understand how to construct the entire device without undue experimentation. Similarly, a person of ordinary skill in the art can envision that the steps of the method can be performed in different orders according to the specific needs of use. Some details are omitted in the drawings, but the inventor believes that it is unnecessary to add these details in order to fully understand the features of the disclosed invention. These omitted details include, in particular, elements for holding or fixing the device or its functional parts, etc. For ease of understanding, some features of the embodiment are enhanced. The disclosed embodiments and the alternatives discussed should not be construed as limiting the present invention in any way.

[0085] Figure 1 One embodiment of a method for isotope separation of lithium is shown.

[0086] In this embodiment, the Li / LiH mixture 104 (first mixture) undergoes a heating step 106. After heating, the Li / LiH mixture 104 is at a first temperature, such as about above 500°C, in a step 108 where the mixture is above 500°C. Subsequently, a first slow uniform cooling step 110 is performed. The Li / LiH mixture 104 is then cooled until the mixture reaches a second temperature, such as about 400°C, in a step 112 where the mixture is about 400°C. This step results in the formation of a hydrogen compound. 7 A portion of the first lithium isotope of LiH is precipitated, and this step can be referred to as 7 LiH precipitation step 114. At this point, the process can be divided into two branches. 7 In the LiH separation step 124, the first branch leads to 7 LiH is separated from the remaining Li / LiH mixture 104. The remaining Li / LiH mixture 104 (without 7 LiH) can be called as non- 7 The second Li / LiH mixture 122 of LiH. 7 After LiH is separated, it can be 7 LiH is extracted in the extraction step 134. The second branch process cools the second Li / LiH mixture 122 in the second slow uniform cooling step 116. The second Li / LiH mixture 122 is cooled until the mixture reaches a third temperature, such as about 398°C, in the step 118 where the mixture is about 398°C. At this temperature, the hydrogen compound 6Another lithium isotope begins to precipitate as part of the LiH. This stage is called 6 LiH precipitation step 120. At this stage, there may be two different branches. In the first branch, 6 The isotopes are separated in a LiH separation step 130. Once separated, the isotopes can be used in subsequent 6 The LiH is extracted in the extraction step 136. The second branch is the reformation of the Li / LiH mixture 104, and the process can be restarted, or 6 The third Li / LiH mixture formed in the second branch after the LiH precipitation step 120 can be used as the first mixture for repeating the process.

[0087] Alternatively, the process can be 7 After the precipitation step 114 of LiH and after obtaining the second Li / LiH mixture 122, the process is restarted, but without continuing with the branch that processes the second cooling and leads to 6 LiH precipitation step 120 .

[0088] When referring to uniform cooling (or being cooled uniformly), this means that the cooling is substantially uniform throughout the volume of the mixture, and when referring to slow cooling, this means that the cooling rate is less than, for example, 1°C per minute.

[0089] Figure 1 The temperatures shown are indicative temperatures and may depend on the concentration of lithium hydride in the mixture.

[0090] Figure 2 It shows that it can be reproduced Figure 1 An embodiment of an apparatus for the method. Figure 2 The device includes a chamber 214 having an inlet at the top and a discharge port at the bottom. The device has a heating device, which can be described as a coil 202 for ohmic heating, or it can be another heating mechanism, such as an induction heating coil. In order to center the device, a centering magnet 206 can be placed near the top of the device. The device can also be lifted, and a lifting magnet 210 can also be provided for this purpose. The motor 212 can be coupled (e.g., connected) to the shaft 208. The shaft 208 can be coupled (e.g., connected) to the chamber 214 so that the chamber 214 can rotate. The device can be covered by a cooling jacket 204. The cooling jacket 204 can include a device for conveying a coolant so that it can cool the interior of the chamber 214.

[0091] Operation Example

[0092] according to Figure 3 and Figure 4 The phase diagram in Figure 1The method described in the diagram can be applied to mixtures containing lithium and lithium hydride of different molar compositions. Figure 3 and Figure 4 The abscissa represents the molar concentration of LiH in the Li / LiH mixture.

[0093] The mixture comprising lithium and lithium hydride may also comprise lithium deuteride and / or lithium tritide.

[0094] Figure 3 Two trajectories are identified as examples of meaningful operation of the method. It should be understood that these two trajectories are not limiting, and other trajectory lines with different LiH molar concentrations can also be used. A person of ordinary skill in the art should be able to determine the optimal molar composition according to the needs of the specific use of the method.

[0095] The first track 302 may be obtained from Figure 1 The Li / LiH mixture 104 starts with a LiH molar composition of about 5% in the alpha liquid phase α(l) and a temperature equal to or greater than about 500° C. When the Li / LiH mixture 104 is cooled below about 500° C., it separates into a liquid (alpha phase α(l)) and a solid (β phase β(s)).

[0096] The second trajectory 306 may start with a Li / LiH mixture 104 having a LiH molar composition of about 85% and a temperature above about 900° C. As the Li / LiH mixture 104 cools, it splits into two different liquid phases, α and β (α(l)+β(l)). As the Li / LiH mixture cools further, the β phase solidifies into a β solid phase (β(s)).

[0097] like Figure 4 As shown, in the α liquid phase and the β solid phase (α(l) + β(s)), especially if the cooling is uniform and 7 The precipitation temperature of LiH stops at 6 At the precipitation temperature of LiH, the α phase α(l) is rich in Li( 6 Li, 7 Li), in 6 LiH may also be rich in 6 LiH; especially if cooled evenly and 7 The precipitation temperature of LiH stops at 6 In the case of LiH precipitation temperature, the β solid phase β(s) is rich in LiH. 6 LiH may be particularly rich above the precipitation temperature 7 LiH.

[0098] Therefore, a transition temperature dependent on the molar concentration of LiH can be used to separate 6 LiH and7 LiH isotopes. Depends on the molar concentration of LiH, 6 The precipitation temperature of LiH may be related to 7 The precipitation temperature of LiH differs by a few degrees. 6 The precipitation temperature of LiH may be lower than 7 The precipitation temperature of LiH. For example, 7 The precipitation temperature of LiH and 6 The difference between the precipitation temperatures of LiH can be between 1°C and 5°C, or even between 2°C and 4°C, which is sufficient for isotopic separation.

[0099] In chemistry, it is well known that molecules experience the "isotope effect", i.e. behave slightly differently, depending on the specific isotope used for each atom. This is a general effect that can be explained by the fact that atoms of different isotopes interact with each other with almost the same forces, but have different masses. This effect can explain why the phase diagram of the Li / LiH system changes depending on the specific H isotope, which can be H, D (deuterium) or even T (tritium). That is, depending on the H isotope in the Li / LiH system, the transition temperature from one phase to another or from one phase to two different phases is slightly different, for example the temperature difference is a few degrees, as described by Hans U. Borgostedt and Cherian K. Mathews in "Applied Chemistry of the Alkali Metals" (pages 136-140).

[0100] Still due to the different isotopic masses, the phase diagram of the Li / LiH system is expected to vary depending on the specific Li isotope, and the transition temperatures are expected to be slightly different depending on the Li isotope in the Li / LiH system. Figure 4 As shown, these temperature differences are expected to be of the same order of magnitude as the temperature differences of the H isotopes in the Li / LiH system, e.g., a temperature difference of a few degrees, because 6 Li and 7 The mass difference between Li is the same as the mass difference between H and D (one neutron).

[0101] Therefore, the isotope 6 LiH and 7 These differences between LiH allow 6 Li / 7 Li / 6 LiH / 7 Selective precipitation in LiH solution 6 LiH or 7 LiH.

[0102] Figure 3 and Figure 4It is further shown that for any LiH molar concentration in a Li / LiH mixture, for example 2% to 95% molar concentration, the Li / LiH phase diagram (e.g. Figure 3 or Figure 4 The Li / LiH phase diagram (Figure 5) is used to determine the transition temperature suitable for separating the isotopes of LiH.

[0103] Figure 2 The first embodiment of the apparatus 200 for isotope separation of lithium can be implemented as follows: Figure 1 The steps of the method. The Li / LiH mixture 104 is deposited from the inlet at the top of the device into the chamber 214 of the device. The Li / LiH mixture 104 can then be heated by the heating coil 202. Once the Li / LiH mixture 104 is in step 108 where the mixture is above 500°C, the cooling jacket 204 can be used to cool the Li / LiH mixture 104 during the first slow uniform cooling step 110 or the second slow uniform cooling step 116. In order to separate isotopes, the chamber 214 can be rotated. Since the chamber 214 is coupled to the motor 212 via the shaft 208, the chamber 214 rotates when the motor 212 is running. The rotation of the chamber 214 can be used to separate the Li / LiH mixture 104 into the constituent phases α and β of the Li / LiH mixture 104 using effects such as density differences. In other words, for example, a phase rich in 7 LiH and / or 6 The beta phase of LiH is denser and therefore accumulates at the outer radius when subjected to centrifugal forces. In this embodiment, the shape of the device allows liquid or solid matter that accumulates at the bottom of the chamber 214 to be discharged. This function of the shape can be achieved in other ways or by a different shape. For example, in another embodiment, the shape can be described as a bell, an inverted bell, a diamond, or other shape that allows solid or liquid matter to accumulate at the bottom.

[0104] Other devices may be used to perform the steps of the method according to the embodiment. Another example of a device is given in European patent application No. EP22305438, entitled "Device and method for extracting lithium hydride", filed on April 4, 2022 by the same applicant "RENAISSANCE FUSION", which is incorporated herein by reference to the maximum extent permitted by law. In addition, after the isotope separation of lithium, the method described in the above application or at least some steps of the method can be used to separate lithium from lithium hydride.

[0105] Example embodiments of the invention are summarized here. Other embodiments may also be understood from the entire specification and claims submitted herein.

[0106] Example 1: A method for isotope separation of lithium, the method comprising:

[0107] - providing a first mixture (104) comprising at least lithium, lithium hydride and possibly lithium deuteride and / or lithium tritide, the first mixture being at a first temperature;

[0108] a first cooling step (110), the first cooling step preferably being a uniform cooling step, the first cooling step being adapted to cool the first mixture to a second temperature lower than the first temperature, and the first cooling step being adapted to precipitate a first portion of lithium hydride having a first lithium isotope;

[0109] - a first separation step (124) suitable for separating a first portion of the precipitated lithium hydride from the first mixture to form a second mixture (122).

[0110] Example 2: The method according to Example 1, wherein the method further comprises a first extraction step (134), the first extraction step being suitable for extracting a first portion of the precipitated lithium hydride after or during the first separation step (124).

[0111] Example 3: The method according to Example 1 or 2, wherein the method further comprises:

[0112] a second cooling step (116), the second cooling step preferably being a uniform cooling step, the second cooling step being adapted to cool the second mixture (122) to a third temperature lower than the second temperature, and the second cooling step being adapted to precipitate a second portion of lithium hydride having a second lithium isotope; and

[0113] - a second separation step (130) suitable for separating a second portion of the precipitated lithium hydride from the second mixture to form a third mixture.

[0114] Example 4: The method according to Example 3, wherein the method further comprises a second extraction step (136), the second extraction step being suitable for extracting a second portion of the precipitated lithium hydride after or during the second separation step (130).

[0115] Example 5: The method according to any one of examples 1 to 4, wherein the first cooling step and / or the second cooling step is slow, for example having a cooling rate of less than 1°C per minute.

[0116] Example 6: The method according to any one of Examples 1 to 5, wherein providing the first mixture (104) includes a heating step (106), the heating step being suitable for heating the first mixture to a first temperature.

[0117] Example 7: The method according to any one of Examples 1 to 6, wherein the method comprises repeating the providing step and repeating the following step:

[0118] - a first cooling step and a first separation step, at least part of the second mixture being used as the first mixture; and / or

[0119] - a second cooling step and a second separation step, at least part of the third mixture being used as the first mixture.

[0120] Example 8: The method according to any one of Examples 1 to 7, wherein the first isotope is 7 Li isotope, the second isotope is 6 Li isotopes.

[0121] Example 9: The method according to any one of Examples 1 to 8, wherein

[0122] - the first temperature is above about 410° C., for example above about 500° C.;

[0123] - the second temperature is between 390° C. and 410° C., for example approximately equal to 400° C.; and / or

[0124] - The third temperature is between 388°C and 408°C, for example approximately equal to 398°C.

[0125] Example 10: The method according to any one of Examples 1 to 9, wherein at least one of the first separation step and the second separation step comprises rotating the first mixture and / or the second mixture, such as rotating the chamber (214) containing the mixture.

[0126] Example 11: A device (200), the device being suitable for implementing the method according to any one of Examples 1 to 10, wherein the device comprises:

[0127] - a chamber (214) adapted to contain a mixture (104) comprising at least lithium and lithium hydride; and

[0128] - Cooling means adapted to cool the mixture in the chamber.

[0129] Example 12: The apparatus of Example 11, wherein the chamber (214) comprises an inlet at the top and a drain at the bottom.

[0130] Example 13: The apparatus of example 11 or 12, wherein the cooling mechanism comprises a cooling jacket (204) and means for conveying a coolant in the cooling jacket, the cooling jacket at least partially covering the chamber.

[0131] Example 14: The device according to any one of Examples 11 to 13 further includes a heating device (202), which is suitable for heating the mixture in the chamber, and the heating device is, for example, an ohmic heating device or an induction heating device.

[0132] Example 15: The apparatus according to any one of Examples 11 to 14 further comprises a rotating device adapted to rotate the chamber, such as a shaft (208) coupled to the chamber and a motor (212) located outside the chamber.

[0133] Example 16: The device according to any one of Examples 11 to 15, wherein the shape of the chamber (214) allows liquid or solid matter accumulated at the bottom of the chamber to be discharged, and the shape of the chamber is, for example, bell-shaped, inverted bell-shaped or diamond-shaped.

[0134] Various embodiments and variations have been described herein. Those skilled in the art will appreciate that certain features of these embodiments may be combined, and those skilled in the art will readily conceive of other variations.

[0135] Finally, based on the functional description provided above, actual implementation of the embodiments and variations described herein is within the capabilities of those skilled in the art.

[0136] List of abbreviations:

[0137] 6 Li: Lithium-6

[0138] 7 Li: Lithium-7

[0139] COLEX: Column Exchange

[0140] OREX: Organic Exchange

[0141] ELEX: Electronic Exchange

[0142] LiOH: lithium hydroxide

[0143] LiCl: Lithium Chloride

[0144] DEMO: Demonstration Power Plant

[0145] LiH: Lithium Hydride

[0146] Li: Lithium

[0147] 7 LiH: Lithium hydride-7

[0148] 6 LiH: Lithium 6 Hydride

Claims

1. A method for isotope separation of lithium, the method comprising: - providing a first mixture (104) comprising at least lithium and lithium hydride, the first mixture being at a first temperature; a first cooling step (110), the first cooling step preferably being a uniform cooling step, the first cooling step being adapted to cool the first mixture to a second temperature lower than the first temperature, and the first cooling step being adapted to precipitate a first portion of the lithium hydride having a first lithium isotope; - a first separation step (124) suitable for separating the first portion of the precipitated lithium hydride from the first mixture to form a second mixture (122); as well as - a first extraction step (134) suitable for extracting said first portion of said separated lithium hydride after or during said first separation step (124).

2. The method according to claim 1, wherein: The first cooling step is performed slowly, for example, the first cooling step has a cooling rate of less than 1° C. per minute.

3. The method according to claim 1 or 2, wherein: The method further comprises: a second cooling step (116), which is preferably a uniform cooling step, which is suitable for cooling the second mixture (122) to a third temperature lower than the second temperature, and which is suitable for precipitating a second portion of the lithium hydride having a second lithium isotope; - a second separation step (130) suitable for separating said second portion of said precipitated lithium hydride from said second mixture to form a third mixture; and - a second extraction step (136) suitable for extracting said second portion of said separated lithium hydride after or during said second separation step (130).

4. The method according to claim 3, wherein: The second cooling step is performed slowly, for example, the second cooling step has a cooling rate of less than 1° C. per minute.

5. The method according to any one of claims 1 to 4, wherein: Providing the first mixture (104) includes a heating step (106) adapted to heat the first mixture to the first temperature.

6. The method according to any one of claims 1 to 5, wherein: The method comprises repeating the providing step and repeating the following steps: - the first cooling step and the first separation step, at least part of the second mixture is used as the first mixture; and / or - a second cooling step and a second separation step, at least part of the third mixture being used as the first mixture.

7. The method according to any one of claims 1 to 6, wherein: The first isotope is 7 Li isotope, the second isotope is 6 Li isotopes.

8. The method according to any one of claims 1 to 7, wherein: - the first temperature is higher than 410°C, for example higher than 500°C; - said second temperature is lower than or equal to 410°C, for example between 390°C and 410°C, for example approximately equal to 400°C; and / or - the third temperature is lower than or equal to 408°C, for example between 388°C and 408°C, for example approximately equal to 398°C.

9. The method according to any one of claims 1 to 8, wherein: At least one of the first separation step and the second separation step includes rotating the first mixture and / or the second mixture, for example rotating a chamber containing the first mixture and / or the second mixture (214).

10. The method according to any one of claims 1 to 9, wherein: The first temperature, the second temperature, and for example, the third temperature are determined according to the concentration of the lithium hydride in the first mixture.

11. The method according to any one of claims 1 to 10, wherein: The first temperature and the second temperature and, for example, the third temperature are determined using a Li / LiH phase diagram.

12. The method according to any one of claims 1 to 11, wherein: The molar concentration of the lithium hydride in the first mixture is between 2% and 95%, for example, between 2.5% and 95%.

13. The method according to any one of claims 1 to 12, wherein: The second temperature and the third temperature are both greater than 200°C, for example greater than 210°C.

14. A device (200) adapted to implement the method according to any one of claims 1 to 13, wherein: The device comprises: - a chamber (214) adapted to contain a mixture comprising at least lithium and lithium hydride; and - Cooling means adapted to cool the mixture in the chamber.

15. The device according to claim 14, wherein: The cooling mechanism comprises a cooling jacket (204) and means adapted to convey a coolant in the cooling jacket, the cooling jacket at least partially covering the chamber.

16. The device according to claim 14 or 15, further comprising a heating device (202) adapted to heat the mixture in the chamber, such as an ohmic heating device or an induction heating device.

17. Apparatus according to any one of claims 14 to 16, further comprising rotating means adapted to rotate the chamber, such as a shaft (208) coupled to the chamber and to a motor (212) located outside the chamber.

18. Apparatus according to any one of claims 14 to 17, wherein: The shape of the chamber (214) enables liquid or solid matter accumulated at the bottom of the chamber to be discharged, and the shape of the chamber is, for example, a bell shape, an inverted bell shape, or a diamond shape.

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