WO2013166506A2

WO2013166506A2 - Non-centrifugal contactor for molten-salt tritium-extraction process

Info

Publication number: WO2013166506A2
Application number: PCT/US2013/039751
Authority: WO
Inventors: Joseph C. Farmer; Michael Dunne
Original assignee: Lawrence Livermore National Security LLC
Current assignee: Lawrence Livermore National Security LLC
Priority date: 2012-05-04
Filing date: 2013-05-06
Publication date: 2013-11-07
Anticipated expiration: 2014-11-04
Also published as: WO2013166505A3; WO2013166506A3; WO2013166505A2

Description

NON-CENTRIFUGAL CONTACTOR FOR MOLTEN-SALT TRITIUM- EXTRACTION PROCESS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001 ] This application claims the benefit of U.S. provisional application serial number 61/643,066 filed May 4, 2012 and the benefit of U.S. provisional application serial number 61/643,119 filed May 4, 2012. Both of these applications are hereby incorporated by reference.

GOVERNMENT RIGHTS

[0002] This invention was made with government support under DE-AC52-

07NA27344 awarded by the Department of Energy. The government has certain rights in the invention.

INTRODUCTION

[0003] Tritium is an important radioisotope used in a broad range of applications, ranging from emergency exit lighting to nuclear weapons. In the future, tritium will serve as the primary fuel for fusion reactors, which will eventually supply much of the energy required by civilization.

[0004] Fusion reactors now on the drawing table, including LLNL's LIFE reactor, require liquid lithium blankets for cooling and breeding tritium fuel. The tritium fuel must be continuously removed from the blanket so that it can be returned to the reactor for burning, via target manufacturing in the case of LIFE. The baseline process for accomplishing this in the LIFE reactor is the well-known Maroni process which uses high-temperature molten mixed alkali-metal halide salts (LiCI:LiF:LiBr at 530°C) as an extraction solvent. With the generation of hydrogen isotopes, liquid and gaseous acids such as HCI, HF and HBr (and the deuterium and tritium analogs) form in the salt phase, making these solvents very corrosive, with other problems due to volatility. The separation of the molten lithium and molten chloride salt phases requires numerous high- temperature (530°C) high-speed centrifugal separators, with bearings and seals exposed to the highly corrosive fluids. Following extraction of lithium tritide from the molten lithium, the tritide anion must undergo electrochemical oxidation in a high-temperature electrochemical cell to form tritium gas, which can then be separated by stripping in a stream of inert gas such as xenon or helium. The volatility of hydrogen chloride or the tritium analog (HC1 or TCI), hydrogen fluoride or the tritium analog (HF or TF) and hydrogen bromide or the tritium analog (HBr or TBr) complicate this separation.

[0005] Currently, centrifugal contactors are used to contact the liquid lithium in which the tritium is bred with a molten salt extraction solvent. These high-speed centrifugal contactors must operate at high temperature for prolonged periods of time without failure. Centrifugal contactors have not yet been successfully operated at these extreme temperatures, where the materials of construction suffer significant losses of strength. Such rotating machinery, with a highly corrosive molten salt electrolyte, and a liquid lithium phase threatening liquid metal embrittlement is a source of substantial concern. A contactor capable of operation without any moving parts would be an advance in the art.

SUMMARY

[0006] A method for removing lithium tritide (LiT) from a lithium blanket is provided. The method is used to recover tritium for reuse, for example, in fabricating targets for an ICF fusion engine. The method involves transferring molten lithium containing LiT from the lithium blanket to a non-centrifugal contactor and carrying out further extraction and the separation steps to recover the tritium. In an embodiment, the method involves extracting a fraction of the LiT from the molten lithium into a solvent phase by contacting the molten lithium phase in an extraction column of the contactor with a solvent phase containing a molten lithium salt. After contacting, the phases are separated by gravity or by use of a cyclonic or hydrocyclonic phase separator. The solvent phase is recovered, at which time it contains a fraction of LiT present in the molten lithium before the contacting. Finally, the solvent phase containing LiT is subjected to an electrochemical process to recover tritium for reuse. In various embodiments, the method involves separating the phases in a cyclonic phase separator, which may also be referred to as a hydrocyclonic phase separator, that is fluidically connected to the extraction column of the non-centrifugal contactor.

[0007] In various embodiments, methods for use of the non-centrifugal separator involve one or more of 1) increasing interfacial area during contacting of the two phases in the extraction column; 2) increasing turbulence in the reactor to increase the mass transfer coefficient during contacting; 3) sizing the extraction column to provide adequate residence time for the extraction to occur during contacting of the two phases; and 4) consolidating and separating the lithium and salt phases after the contacting. Advantageously, the separator has no moving parts.

[0008] In various embodiments, the interfacial area between the two phases is increased through the use of ultrasonic emulsification during the contacting. Alternatively or in addition, the interfacial area is increased by providing one or more distributor plates disposed in the flow path of the extraction column to break one or both of the phases into dispersed droplets. In addition, turbulence can be increased by providing the extraction column with fixed or spinning axial turbulence promoters in a flow channel of the extraction column. Turbulence can also be increased by electromagnetic pulsing of the molten lithium phase in the extraction column, thereby achieving a high differential velocity between the two phases.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic depiction of a high-temperature centrifugal contactor;

[0010] Figure 2 is a plot of lithium tritide concentration in lithium and salt phases as a function of contactor residence time;

[0011 ] Figure 3 is a plot illustrating the relationship between the fractional extraction efficiency and the interphase contact area.

[0012] Figure 4 shows dependence of the fractional extraction efficiency on lithium flow rate, showing improved efficiency at lower flow rates, due to the correspondingly longer residence time;

[0013] Figure 5 illustrates a vertical extraction column with two distributor plates on opposite ends of the column;

[0014] Figure 6 is a graph showing calculated tritium concentration in liquid lithium phase for vertical extraction column of the type shown in Figure 5;

[0015] Figure 7 shows calculated tritium concentration in molten salt phase for vertical extraction column of the type shown in Figure 5; [0016] Figure 8 shows the corresponding total (combined) column heights for the vertical extraction column of the type shown in Figure 5;

[0017] Figure 9 shows the corresponding total (combined) column volumes for the vertical extraction column of the type shown in Figure 5;

[0018] Figure 10 illustrates a vertical extraction column with no optimization (10 m x 15 m x 15 m);

[0019] Figure 11 shows enhanced mass transfer and extraction efficiency through the use of fixed and/or spinning axial turbulence promoters in cylindrical or in a rectangular flow channel;

[0020] Figure 12 shows enhanced mass transfer and extraction efficiency through the use of bi-stable hydrofoil type turbulence promoters in cylindrical or in a rectangular flow channel;

[0021 ] Figure 13 shows enhanced mass transfer and extraction efficiency through the use of acoustic emulsification and mass transfer enhancement in cylindrical or in a rectangular flow channel;

[0022] Figure 14 illustrates phase separation with flow-induced cyclonic action;

[0023] Figure 15 illustrates electromagnetic pulsing; and

[0024] Figure 16 illustrates process flow for a multistage extraction process.

DESCRIPTION

[0025] The methods described herein involve extracting lithium tritide from a lithium metal phase by using molten lithium salt as an extraction solvent. The two phases involved in the extraction will be referred to under various names, according to the aspect of the invention being emphasized. Thus, as used herein, the phase containing molten lithium metal with dissolved lithium tritide is characterized as the molten lithium phase, as the lighter phase, as the a (or alpha) phase, as the lithium phase, and other equivalents. On the other hand, the phase into which dissolved tritide is extracted is variously called the solvent phase, the heavy phase, the β (or beta) phase, and other equivalent nomenclature. In all of the embodiments described herein, the lithium phase contains dissolved lithium tritide and arises, for example, from use as a heat transfer fluid or coolant for a nuclear fusion reactor. In various embodiments, the lithium salt used as an extraction solvent is selected from lithium hydroxide, lithium carbonate, lithium chloride, lithium bromide, lithium fluoride, and mixed pseudo ternary solvents consisting of a mixture of lithium chloride, lithium bromide, and lithium fluoride. In one embodiment, the lithium salt comprises lithium chloride, lithium bromide, and lithium fluoride. In other embodiments, the lithium salt use as the solvent of extraction contains all three of lithium chloride, lithium bromide, and lithium fluoride.

[0026] In one embodiment, the method involves extracting LiT from a lighter

(less dense) a phase containing LiT and molten Lithium metal into a heavier (more dense) β phase containing a molten lithium salt. The method involves contacting the a phase and β phase with one another in an extraction column of a non-centrifugal contactor. The beta phase after contacting contains a fraction of the LiT that was present in the alpha phase at the start of contacting. In one aspect, dispersed droplets of the a phase are introduced into the extraction column, which contains the beta phase as a continuous phase. Alternatively or in addition, dispersed droplets of the beta phase are introduced into the extraction column containing the alpha phase as a continuous phase. In certain embodiments, the extraction column is disposed in a gravitational field such that point of introduction of the alpha phase has a lower gravitational potential energy then a point of introduction of the beta phase. Because the lighter alpha phase is introduced below the heavier beta phase, gravity acts to make the lighter phase rise and the heavier phase fall, increasing the turbulence in the system and increasing the differential velocity between the phases. In embodiments, particles of the alpha phase coalesce and exit the reactor at the top of the extraction column, while the particles of the beta phase coalesce after contact and exit at the bottom of the extraction column.

[0027] Multistage separation can also be carried out, thereby achieving a higher overall separation efficiency. In an embodiment, the method further involves subjecting the alpha phase, containing a reduced level of LiT after contacting, to extraction with another portion of a molten lithium salt. As in other embodiments, after contacting, the alpha and beta phases can be separated in a cyclonic or hydrocyclonic phase separator.

[0028] In another embodiment, a method provides for removing LiT from a lithium blanket of a nuclear fusion reactor to recover tritium for reuse, for example in fabricating targets for an ICF fusion engine. The method involves extracting LiT from a molten lithium phase into a solvent phase and separating and collecting the phases using a non-centrifugal contactor. The method involves first transferring molten lithium containing LiT from a lithium blanket to a non-centrifugal separator. Then a fraction of the LiT from the molten lithium is extracted into a solvent phase by contacting the molten lithium phase in an extraction column of the contactor with the solvent phase comprising a molten lithium salt. Then the phases are separated by gravity or by use of a cyclonic or hydrocyclonic separator, and the solvent phase containing LiT is subjected to an electrochemical process to recover tritium for reuse.

[0029] In various embodiments, methods for use of the non-centrifugal contactor involve 1) increasing interfacial area during contacting of the two phases in the extraction column; 2) increasing turbulence in the reactor to increase the mass transfer coefficient during contacting; 3) sizing the extraction column to provide adequate residence time for the extraction to occur during contacting of the two phases; and 4) consolidating and separating the lithium and salt phases after the contacting. Advantageously, the separator has no moving parts.

[0030] In various embodiments, the method involves separating the phases in a cyclonic or hydrocyclonic phase separator fluidically connected to the extraction column of the non-centrifugal separator. As another embodiment, the interfacial area during the two phases is increased through the use of ultrasonic emulsification during the contacting. Alternatively or in addition, the interfacial area is increased by providing one or more distributer plates disposed in the flow path of the extraction column to break one or both phases into dispersed droplets. Alternatively or in addition, turbulence is increased by providing the extraction column with fixed or spinning axial turbulence promoters in a flow channel in the extraction column. Finally, turbulence can also be increased by electromagnetic pulsing of the molten lithium phase in the extraction column, thereby achieving a higher differential velocity between the two phases.

[0031 ] In another embodiment, a continuous method for extracting lithium tritide is provided using a gravity driven contactor with optional electromagnetic pulsing. The method involves extracting lithium tritide from a lighter a phase containing LiT and molten lithium metal into a heavier β phase containing a molten lithium salt. The method involves contacting the phases during two phase flow in a gravity driven non- centrifugal contactor.

[0032] The method involves the steps of:

(a) optionally delivering a first feed comprising a fraction of the lighter phase into an inlet in a lower region of an extraction column of the separator and then through a first distributer plate, wherein the distributer plate comprises a plurality of through-holes and the first feed is turned into a plurality of dispersed droplets by passing through the holes in the distributer plate;

(b) optionally, simultaneously delivering a second feed comprising the rest of the lighter phase into the extraction column to form a continuous alpha phase in the extraction column; (c) optionally, simultaneously delivering a third feed comprising a fraction of the heavier phase into an upper region of the extraction column through a second distributer plate, wherein the distributer plate comprises a plurality of through-holes and the third feed is turned into a plurality of dispersed droplets by passing through the holes in the distributer plate;

(d) optionally, simultaneously delivering a fourth feed comprising the rest of the heavier phase into the extraction column to form a continuous beta phase in the reactor; (e) consolidating the lighter phases from the optional first and second feeds in an upper region of the extraction column and drawing off the lighter phase containing a reduced level of LiT from the extraction column as a lithium outlet stream; and (f) consolidating the heavier phases from optional third and fourth feeds in a lower region of the extraction column and drawing off the heavier phase from the reactor, wherein the heavier phase contains a portion of the LiT present in the lighter phases before the extraction, with the proviso that at least one of the optional first and second feeds is carried out; and with the further proviso that at least one of the optional third and fourth feeds is carried out; and with the yet further proviso that at least one of the optional first and third feeds is carried out.

[0033] In this embodiment, the non-centrifugal contactor is capable of operating to separate the heavy and light phases without needing the cyclonic or hydrocyclonic separator fluidically attached to the extraction column. Operation of this embodiment is illustrated in Figure 5. In embodiments, dispersed droplets of the lighter phase rise through a continuous heavier phase in the extraction column, dispersed droplets of the heavier phase fall through a continuous lighter phase in the extraction phase, or both. As in other embodiments, the method can further involve electromagnetically pulsing the lighter a phase which consists of molten lithium metal to increase the differential velocity between dispersed droplets and the continuous phase. Pulsing can be accomplished in various ways, including passing current through the flowing molten lithium, in a direction perpendicular to the flow direction, in the presence of a superimposed magnetic field.

[0034] In this and other embodiments, the methods involve feeding the lighter phase to an extraction column at a rate 1-20 kg/sec. Where a method involves more than 1 feed of the lighter phase, the rate of 1-20 kg/sec is divided between the first and second feeds. In other embodiments, the rate is 5-10 kg/sec, or about 7 kg/sec. In this and other embodiments, the concentrations of LiT in the feeds to the extraction column are typically on the order of 0.1 to 10 ppm, 0.3 to 3 ppm, or 0.5 to 2 ppm.

[0035] In various embodiments of methods described herein, the

extraction column has a volume size to achieve a suitable residence time for the extraction. In a non-limiting example, the extraction column has a volume of 5 to 20 m . Thus in various embodiments, the lighter phase containing lithium metal and lithium tritide is fed at a rate of 1-20 kg/sec, the concentration of LiT in the lighter phase is 0.1 to 10 ppm, extraction column has a volume of 5 to 20 m . In certain embodiments, the lighter phase is fed at a rate of about 7 kg/sec, the concentration of LiT in the lighter phase at the inlet to the extraction column is about 1 ppm, and the reactor has a volume of about 15 m .

[0036] It is to be appreciated that the methods can be carried out continuously, and can involve a multistage process. In a multistage process for extracting LiT from molten lithium phase into a molten salt phase, the method involves carrying out extraction and phase separation (such as by using the continuous method of steps a) through f) above), and then delivering the lithium outlet stream as a feed into a second contactor, then repeating the steps using fresh molten lithium salt as extraction solvent.

[0037] Finally, a general method is provided of extracting LiT in a non- centrifugal contactor containing an extraction column fluidically coupled to a cyclonic or hydrocyclonic phase separator. Thus, a method of removing LiT from a lithium blanket in an ICF fusion engine by extracting a lithium phase containing molten lithium salt and LiT with a salt phase containing a molten lithium salt is provided.

[0038] The method involves a. transferring, generally by pumping such as by electromagnetic pumping, the lithium phase from the lithium blanket through an inlet of an extraction column of a non-centrifugal separator to form a continuous lithium phase in the extraction column; b. simultaneously delivering a salt phase into the extraction column through a distributor plate. The distributor plate has a plurality through holes, and the salt phase is delivered with pressure as a plurality of dispersed droplets into the continuous lithium phase; c. contacting the dispersed droplets of the lithium salt phase with the continuous lithium phase in the extraction column for sufficient time of the fraction of the LiT of the lithium phase passes into the salt phase. d. delivering the combined lithium and salt phases into a cyclonic or

hydrocyclonic phase separator; and e. separating the phases in the cyclonic or hydrocyclonic phase separator to produce an outlet stream of lithium metal having a reduced concentration of LiT and an outlet stream of salt containing a fraction of the LiT that was in the lithium phase at the inlet in step a.

[0039] The method can further comprise electromagnetic ally pulsing the extraction column to increase the velocity differential between the heavy salt droplets and the electrically conductive continuous lithium phase. In an embodiment, at least a portion of the outlet stream of lithium metal can be delivered back to the inlet, where it is subject to extraction again with the salt phase.

[0040] In a multistage variation, the method involves delivering the outlet stream of lithium metal to the inlet of a second contactor and extracting again with a salt phase containing fresh molten lithium salt. If desired, the salt phase and lithium phase in the extraction column can be agitated with ultrasonic energy.

Gravity Driven Contactor

[0041] Operation of a gravity driven contactor is illustrated in Figure 5, with the two phases being designated as an alpha phase with density p_a and a beta phase with density p . A fraction f_a of the alpha phase flow G_a enters the extraction column at the bottom through a distributor plate. The distributor plate turns the flow of the alpha phase into a plurality of dispersed droplets, shown as the ovals in the bottom half of the figure. The up arrows indicate that the alpha phase is the lighter phase that rises under gravity. At the same time, a fraction fp of the flow G of the beta phase enters the column from the top and passes through a distributor plate that likewise turns the flow of the beta phase into a series of droplets. As shown by the down arrows, the droplets of the β phase are more dense and fall by gravity in the extraction column. A third feed comprising the rest of the flow of the beta phase (shown as (l-fp) G in the figure) is delivered into the extraction column to form a continuous beta phase, shown in the figure as the phase in the bottom of the column. Finally, a fourth feed comprising the remainder of the lighter alpha phase (shown in the figure as (l-f_a)G_a ) forms a continuous alpha phase in the extraction column. As illustrated in Figure 5, the heavy phase coalesces at the bottom of the column and the light phase coalesces at the top. As shown, the lighter phase exits at the top of the column and the heavier phase exits at the bottom. The lighter phase drawn off at the top contains a reduced level of LiT and is provided as a lithium outlet stream. The heavier phase contains a portion of the LiT originally present in the lighter phase before the extraction, and is drawn off at the bottom of the column. The dispersed droplets of the heavy β phase are shown having a velocity Up_t, while the lighter dispersed droplets of the lighter a phase are shown having a velocity of U_at- The concentration of LiT in the alpha phase is given by C_a, while that in the heavier beta phase is Cp. The volume of alpha phase upon coalescence is V_a, while the volume of the beta phase is Vp.

[0042] One drawback of the gravity driven contactor is that the relatively low terminal velocities that droplets experience in the simple gravity systems can result in systems that are prohibitively large. The size of the systems can be reduced significantly by using an electromagnetic pulse to drive high differential velocity between the conductive continuous lithium phase and the distributor salt phase.

[0043] Electromagnetic pulsing is illustrated in Figure 15. Figure 15 shows the lighter lithium phase flowing into an extraction column from the bottom and being withdrawn at the top, while the heavier salt phase is added to the top of the extraction column through a distributer plate and withdrawn from the bottom. In an alternative embodiment (not shown in Figure 15) the lighter lithium is added through a distributer plate. In the embodiment shown in Figure 15, the distributor plate creates a plurality of dispersed droplets that fall by the force of gravity to the bottom of the extraction column. A drag force Fa acts in opposition to the force of gravity F_g on the dispersed particles. In electromagnetic pulsing, a magnetic field B is applied to the extraction column and a perpendicular electromagnetic field I is varied or pulsed in order to apply an oscillating force F_EM on the conductive lithium metal of the heavier phase. The result of the electromagnetic pulsing is to increase the differential velocity between the salt phase and the electrically conducted metal. [0044] In an illustrative embodiment, it is assumed that the non-centrifugal contactor needs to accommodate a lithium flow of approximately 7kg/sec and an inlet tritium concentration of 1 ppm. The heavy salt phase is distributed as 50 micron droplets into the continuous lithium phase. Electromagnetic pulsing at a relatively low power (several to 10s of W) and high frequency (10 to 100 kHz) maintains a high differential velocity between the heavy salt droplets and electrically conductive continuous lithium phase. This achieves a relatively high time average velocity and corresponding dropping Reynolds number, which enables achievement of a high time average Sherwood number and mass transfer coefficient. In preferred embodiments, the mass transfer is enhanced to the point where the hermetically sealed contactor with no moving parts can be as compact, and perhaps more compact, than the centrifugal contactor of the prior art. In particular, a single-stage electromagnetic pulsing contactor is capable of approaching equilibrium distribution between phases (e.g. 0.25 ppm) with a modest volume of 15 m . [0045] Multistage operation of an embodiment is illustrated in Figure 16. Figure

16 shows a lithium phase enriched with tritium being extracted with fresh salt in a Stage 1 reactor, with the heavier phase containing extracted lithium tritide being drawn off at bottom of Stage 1 and delivered to Stage l 's cyclonic or hydrocyclonic phase separator. The light phase is drawn off of Stage l's cyclonic phase separator and introduced to a stage 2 extraction column for a re-extraction with fresh salt. Salt enriched with tritium is drawn off at the bottom of the separator. The heavy phase contain extracted LiT is then delivered to a Stage 2 cyclonic or hydrocyclonic phase separator and the sequence repeats. Figure 16 demonstrates a lithium metal feed of 7kg/sec having LiT at approximately concentration 0.1 ppm. After the first extraction and separation, the LiT concentration is 0.0261 ppm, after the second extraction and separation the LiT concentration is 0.0068 ppm.

[0046] An embodiment of a non-centrifugal contactor is shown in Figure 1. Two phase flow 20 enters the contactor 100 through a distributer plate 50 and exits at 40. The contactor 100 includes an extraction column 30 fluidically coupled to a separator 10, which in various embodiments is of the cyclonic or hydrocyclonic design. Other variations in the structure of the contactor will become evident from the further description herein, including inlet ports for the two phases, disposition of distributer plates associated the inlets, disposition of turbulence enhancers in the flow field of the contactor, installation of electromagnetic pulsing, and other features. The contactor is manufactured using materials that are not degraded under the chemical and physical characteristics of the molten lithium and molten lithium salt phases handled in the contactor. Suitable contactors are made from ceramic materials using known investment casting and lost wax procedures.

[0047] In general, the contactor performs the following generalized functions. It provides for maximizing surface area between phases. It creates conditions for high mass transfer by manipulating both phases. It provides for sufficiently long residence time and consolidates and separates the molten lithium phase and the salt phase. It enables the molten- salt extraction of tritium from flowing lithium, while achieving reliability substantially better than that possible with centrifugal contactors. This is achieved by:

1. Avoiding rotating machinery, seals and bearings by relying on simple flow systems.

2. Maximizing interfacial surface area between the two flowing phases by utilizing.

(a) Distributers plates with holes, suspended in the flow,

(b) Ultrasonic emulsification, and/or

(c) Bi-stable flapping hydrofoil surfaces in the flowing stream

3. Providing adequate residence time for inter-phase mass transfer by designing the flow system with sufficient volume

4. Using turbulence to increase their inter-phase mass transfer coefficient by

(a) Increasing the linear velocity

(b) Incorporating turbulence promoters in the flow channel

(c) Achieving high levels of agitation with ultrasonic energy

5. Consolidating and separating the liquid lithium and molten salt phases by utilizing

(a) Flow pulsations causing collision and contact between droplets of

variable size and drag force

(b) Cyclonic action during flow (c) Ultrasonic agglomeration to decrease the surface to volume ratio of the distributed phase.

Contactor Efficiency & Process Mass Balance

[0048] The extraction efficiency, η, depends upon the distribution coefficient (D_v), the overall interphase mass transfer coefficient between the lithium and salt phases (K_M ), the interfacial surface area, A, and the lithium flow rate (F).

[0050] This specific equation is presented in the published literature

[H. Moriyama, Y. Asaoka, Y.Ito, Kinetics of Tritium Recovery from Liquid Lithium by Molten Salt Extraction, Fusion Technology, 19 (1991) 1046-1050]. The overall interphase mass transfer coefficient, represented as a mass transfer resistance (inverse), is then calculated from the two series mass transfer resistances, one for the lithium phase, and the other for the salt phase.

M (Li) ^Kp(salt)

[0052] The fraction of the lithium blanket that must be processed is

then:

£D_y + 1

X -- s^s εΏ_νη

[0053] The corresponding lithium flow rate through the process is then:

P _ R_b £DvV + l

[0054] The dependence of lithium tritide (LiT) solute concentration in the two contacted phases on residence time is shown in Figure 2, showing the solute concentration reaching equilibrium at very long residence time (large contactor volume). Figure 3 shows the relationship between the fractional extraction efficiency and the interphase contact area, with the efficiency increasing dramatically with more surface area. Increased surface area is achieved with smaller droplet sizes, which can be controlled to some extent in the invention described here by the size of holes or pores in the distributer plate. Figure 4 shows the dependence of the fractional extraction efficiency on lithium flow rate, showing improved efficiency at lower flow rates, due to the correspondingly longer residence time.

Contactors Driven by Gravity & Centrifugal Force - Flow Dependence of Mass Transfer Coefficient for Cylinders & Spheres [0055] Consider again the following embodiment of the invention, shown in

Figure 5. The volume following the distributer plate can be configured as a vertical column, thereby enabling the substantial density difference between the liquid lithium and molten salt extraction salt to be exploited to induce flow in the distributed phase. Phases can be consolidated at the extreme ends of the vertical column. In a variant of the vertical column, two distributor plates can be used at extreme ends of the column, one for creating a distributed discontinuous alpha phase at the bottom of the column, and another for creating a distributed discontinuous beta phase at the top of the column.

[0056] Harriott's Method treats particles suspended in agitated vessels as spheres moving at terminal velocity, an application of Stoke' s Law:

[0057] In this expression, d_p is the diameter of the droplets comprising the dispersed phase, p_d is the density of those droplets, p_c is the density of the continuous phase in which the droplets are immersed, g is the acceleration of gravity, and me is the viscosity of the continuous phase. The following equivalences are recognized for the sake of calculating the mass transfer coefficient for the droplets.

D = d_p

[0058] In the case of a dispersed phase consisting of light droplets of lithium rising through a heavier salt phase, or alternatively, heavy droplets of salt falling through a lighter lithium phase, the individual mass transfer coefficients can be calculated from the Sherwood number for a sphere moving at terminal velocity.

[0060] The diffusivity of solute A in phase B is D_AB, the sphere diameter is D, and the Sherwood number is Sh. The Sherwood number is a function of the Schmidt and Reynolds number for an assumed spherical drop moving at terminal velocity. Modified Frossling equation for spheres and cylinders:

S/? = 2 + 0.6Sc^ Re^²

[0061 ] Substitution of the expression for the Sherwood number into the equation defining the mass transfer coefficient yields the following:

[0062] The performance of a gravity-driven vertical extraction column of the type shown in Figure 5 is summarized in the following curves. Figure 6 shows the calculated tritium concentration in the lithium phase as a function of contactor volume for a low diffusivity assumption of 10 -^"5 cm 2 /sec and a high diffusivity assumption of 10 -^"3 cm /sec. Figure 7 shows the calculated tritium concentration in the molten salt phase under the same assumptions. Figures 8 and 9 show the corresponding total (combined) size of the bank of columns, and Figure 10 shows the size of a bank of such vertical extraction columns with no attempt at optimization (lO m x 15 m x 15 m). As a baseline, the performance possible with a simple non-centrifugal gravity-driven system with droplets created by 10, 50, and 100 micron distributor plates has been investigated. Assuming conservative values of diffusivity, such a system is found to be relatively large during preliminary analysis.

Contactors with Reduced Column Size [0063] Various means exist for decreasing the size of the contactors, without having to resort to the problematic rotating machinery involved in conventional centrifugal contactors. 1. In addition to maximizing interfacial surface area between the two flowing phases by utilizing distributer plates with holes suspended in the flow, employ (a) ultrasonic emulsification; and/or (b) bi-stable flapping hydrofoil surfaces in the flowing stream.

2. Continue to provide adequate residence time for inter-phase mass transfer by designing the flow system with sufficient volume.

3. Use induced turbulence to increase the inter-phase mass transfer coefficient between the lithium and salt phases by (a) increasing the linear velocity in flow channels; (b) incorporate fixed turbulence promoters in the flow channel, including radial, vertical, and/or horizontal vanes and blades; (c) employ high levels of agitation with tuned-frequency ultrasonic stimulation, coupling the acoustic transmitter to the high-temperature flow channel with a ceramic, glass, refractory metal, or appropriate amorphous metal coupler, thereby enabling the acoustic energy to be transmitted into the high temperature environment from the source, without exposing the source to the high-temperature environment.

4. Consolidation and separation of the liquid lithium and molten salt phases through the use of (a) flow pulsations causing collision and contact between droplets of variable size and drag force; (b) cyclonic action during flow; and (c) ultrasonic agglomeration to decrease the surface to volume ratio of the distributed phase.

[0064] Figure 11 illustrates a device with enhanced mass transfer and extraction efficiency through the use of fixed and/or spinning axial turbulence promoters in cylindrical or rectangular flow channel. Figure 12 illustrates a device with enhanced mass transfer and extraction efficiency through the use of bi-stable hydrofoil type turbulence promoters in cylindrical or rectangular flow channel. Figure 13 shows a device with enhanced mass transfer and extraction efficiency through the use of acoustic emulsification and mass transfer enhancement in cylindrical or rectangular flow channel. Figure 14 shows a device with phase separation with flow-induced cyclonic action.

EXAMPLES

[0065] Non-limiting embodiments of various aspects of the present teachings are given in the Examples that follow.

Example 1 - contact in a "non-centrifugal contactor"

1. A method of extracting lithium tritide from a lithium phase into a salt phase, comprising contacting a lithium phase containing lithium tritide and molten lithium metal with a salt phase containing molten salts of lithium in a non-centrifugal contactor containing an extraction column, and recovering the molten salt phase containing dissolved lithium tritide.

2. A method according to embodiment 1, comprising contacting dispersed droplets of the lithium phase with the salt phase in the extraction column and separating the resulting phases in a cyclone or hydrocyclone apparatus of the contactor. 3. A method according to embodiment 1, comprising contacting dispersed droplets of the salt phase with the lithium phase, and separating the resulting phases in a cyclone or hydrocyclone apparatus of the contactor.

4. A method according to embodiment 2, comprising introducing molten salt into the extraction column containing molten lithium with dissolved LiT through a distributer plate, whereby dense droplets of molten salt are created that fall under the force of gravity through the lighter molten lithium phase.

5. A method according to embodiment 4, further comprising emulsifying the salt phase in the lithium phase using ultrasonic energy.

6. A method according to embodiment 4, further comprising electromagnetically pulsing the lithium phase in the extraction column to provide a body force that works preferentially on the more conductive lithium metal of the lithium phase.

7. A method according to any of the preceding embodiments, wherein the method is carried out continuously.

8. A method according to any of the preceding embodiments, comprising a) contacting the phases in a first extraction column b) separating the phases in a first cyclonic or hydrocyclonic phase separator, c) collecting the heavy salt phase from the bottom of the first stage cyclonic or hydrocyclonic phase separator, wherein the salt phase is enriched in lithium, and d) optionally feeding the molten lithium phase containing a reduced level of LiT to a second extraction column and repeating steps a), b), and c).

9. A method according to any of embodiments 1 - 8, wherein the lithium salt comprises lithium hydroxide or lithium carbonate.

10. A method according to any of embodiments 1 - 8, wherein the lithium salt comprises lithium chloride, lithium bromide, or lithium fluoride. 11. A method according to any of embodiment 10, wherein the lithium salt comprises lithium chloride, lithium bromide, and lithium fluoride.

Example 2 - alpha and beta phase extraction

1. A method for extracting LiT from an alpha into a beta phase, wherein the alpha phase comprises LiT and molten lithium metal and the beta phase comprises a molten lithium salt, the method comprising contacting the alpha phase and the beta phase in an extraction column of a non- centrifugal contactor and collecting the beta phase, wherein the beta phase after contacting contains a fraction of the LiT that was present in the alpha phase at the start of the contacting.

2. A method according to embodiment 1, wherein dispersed droplets of the alpha phase are introduced into the extraction column containing the beta phase as a continuous phase.

3. A method according to embodiments 1 or 2, wherein dispersed droplets of the beta phase are introduced into the reactor containing the alpha phase as a continuous phase.

4. A method according to any of embodiments 1-3, wherein the extraction column is disposed in a gravitational field such that a point of introduction of the alpha phase has a lower gravitational potential energy than a point of introduction of the beta phase. 5. A method according to embodiment 4, wherein the alpha phase coalesces after contact and exits the reactor at the top of the extraction column, and the beta phase coalesces after contact and exits the reactor at the bottom of the reactor.

6. A method according to embodiments 1-5, further comprising submitting the alpha phase containing a reduced level of LiT after contacting to extraction with another portion of a molten lithium salt, thereby achieving multi-stage separation.

7. A method according to any of embodiments 1-4, wherein after contact the alpha and beta phase are separated in a cyclonic or hydrocyclonic phase separator

8. A method according to any of embodiments 1 - 7, wherein the lithium salt comprises lithium hydroxide or lithium carbonate.

9. A method according to any of embodiments 1 - 7, wherein the lithium salt comprises lithium chloride, lithium bromide, or lithium fluoride.

10. A method according to any of embodiments 1-7, wherein the lithium salt comprises lithium chloride, lithium bromide, and lithium fluoride. Example 3 - contactor with no moving parts

1. A method of removing LiT from a lithium blanket to recover tritium for reuse in fabricating targets for an ICF fusion engine, comprising transferring molten lithium containing LiT from the lithium blanket to a non- centrifugal contactor; extracting a fraction of the LiT from the molten lithium into a solvent phase by contacting the molten lithium phase in an extraction column of the contactor with a solvent phase comprising a molten lithium salt; separating the phases after the contacting by gravity or by use of a cyclonic or hydrocyclonic phase separator; recovering the solvent phase containing a fraction of the LiT present in the molten lithium before contacting; and subjecting the solvent phase containing LiT to an electrochemical process to recover tritium for reuse.

2. A method according to embodiment 1, comprising increasing the interfacial area during contacting of the two phases in the extraction column, increasing turbulence in the reactor to increase the mass transfer coefficient during contacting, sizing the extraction column to provide adequate residence time for the extraction to occur during contacting of the two phases, and consolidating and separating the lithium and salt phases after contact, wherein the contactor has no moving parts.

3. A method according to embodiment 1, comprising separating the phases in a cyclonic or hydrocyclonic phase separator fluidically connected to the extraction column of the non-centrifugal contactor.

4. A method according to embodiment 1, comprising increasing the interfacial area through the use of ultrasonic emulsification during the contacting.

5. A method according to embodiment 1, comprising increasing the interfacial area by providing one or more distributer plates disposed in the flow path of the extraction column to break one or both of the phases into dispersed droplets.

6. A method according to embodiment 1, comprising increasing turbulence by providing the extraction column with fixed or spinning axial turbulence promoters in a flow channel of the extraction column. 7. A method according to embodiment 2, comprising increasing turbulence by electromagnetic pulsing of the molten lithium phase in the extraction column, thereby achieving a higher differential velocity between the two phases.

8. A method according to any of embodiments 1 - 7, wherein the lithium salt comprises lithium hydroxide or lithium carbonate. 9. A method according to any of embodiments 1 - 7, wherein the lithium salt comprises lithium chloride, lithium bromide, or lithium fluoride.

10. A method according to any of embodiments 1-7, wherein the lithium salt comprises lithium chloride, lithium bromide, and lithium fluoride.

Example 4 - Gravity driven contactor with optional EM pulsing 1. A continuous method for extracting lithium tritide from a lighter alpha phase comprising LiT and molten lithium metal into a heavier beta phase comprising a molten lithium salt by contacting the phases during two phase flow in a gravity driven non- centrifugal contactor, comprising (a) optionally delivering a first feed comprising a fraction of the lighter phase into an inlet in a lower region of an extraction column of the separator and then through a first distributer plate, wherein the distributer plate comprises a plurality of through-holes and the first feed is turned into a plurality of dispersed droplets by passing through the holes in the distributer plate; (b) optionally, simultaneously delivering a second feed comprising the rest of the lighter phase into the extraction column to form a continuous alpha phase in the extraction column;

(c) optionally, simultaneously delivering a third feed comprising a fraction of the heavier phase into an upper region of the extraction column through a second distributer plate, wherein the distributer plate comprises a plurality of through-holes and the third feed is turned into a plurality of dispersed droplets by passing through the holes in the distributer plate;

(d) optionally, simultaneously delivering a fourth feed comprising the rest of the heavier phase into the extraction column to form a continuous beta phase in the reactor;

(e) consolidating the lighter phases from the optional first and second feeds in an upper region of the extraction column and drawing off the lighter phase containing a reduced level of LiT from the extraction column as a lithium outlet stream; and (f) consolidating the heavier phases from optional third and fourth feeds in a lower region of the extraction column and drawing off the heavier phase from the reactor, wherein the heavier phase contains a portion of the LiT present in the lighter phases before the extraction, wherein at least one of the optional first and second feeds is carried out, at least one of the optional third and fourth feeds is carried out, and at least one of the optional first and third feeds is carried out .

2. A method according to embodiment 1, wherein dispersed droplets of the lighter phase rise through a continuous heavier phase in the extraction column, dispersed droplets of the heavier phase fall through a continuous lighter phase in the extraction column, or both.

3. A method according to embodiment 2, further comprising electromagnetically pulsing the lithium metal in the alpha phase to increase the differential velocity between dispersed droplets and continuous phase.

5. A method according to embodiment 3, comprising feeding the lighter phase at a rate of 1-20 kg/sec, divided between the second and optional first feeds.

6. A method according to embodiment 5, wherein the rate is 5-10 kg/sec.

7. A method according to embodiment 5, wherein the rate is about 7 kg/sec.

8. A method according to embodiment 3, wherein the concentration of LiT in the second and optional first feeds at the inlet to the extraction column is 0.1 to 10 ppm. 9. A method according to embodiment 8, wherein the concentration of LiT in the second and optional first feeds is 0.3 to 3 ppm.

10. A method according to embodiment 8, wherein the concentration of LiT in the second and optional first feeds is 0.5 to 2 ppm.

11. A method according to embodiment 3, wherein the reactor has a volume of 5-20 m³.

12. A method according to embodiment 11, wherein the lighter phase is fed at a rate of 1-20 kg/sec, the concentration of LiT in the lighter phase is 0.1 to 10 ppm, and the extraction column has a volume of 5-20 m .

13. A method according to embodiment 11, wherein the lighter phase is fed at a rate of about 7 kg/sec, the concentration of LiT in the lighter phase at the inlet to the extraction column is about 1 ppm, and the reactor has a volume of about 15 m .

14. A multistage process for extracting LiT from a molten lithium phase into a molten salt phase, comprising carrying out the continuous method of embodiment 1 and delivering the lithium outlet stream as a first or second feed into an extraction column of a second contactor and carrying out steps (a)-(f) with fresh molten lithium salt.

15. A method according to any of embodiments 1 - 14, wherein the lithium salt comprises lithium hydroxide or lithium carbonate. 16. A method according to any of embodiments 1 - 14, wherein the lithium salt comprises lithium chloride, lithium bromide, or lithium fluoride.

17. A method according to any of embodiments 1 - 14, wherein the lithium salt comprises lithium chloride, lithium bromide, and lithium fluoride.

Example 5 - general method in a contactor with extraction column and cyclonic phase separator:

1. A method of removing LiT from a lithium blanket in an ICF fusion engine by extracting a lithium phase containing molten lithium metal and LiT with a salt phase containing a molten lithium salt, comprising:

(a) transferring the lithium phase from the lithium blanket through an inlet of an extraction column of a non-centrifugal contactor to form a continuous lithium phase in the extraction column;

(b) simultaneously delivering a salt phase into the extraction column through a distributer plate, wherein the distributer plate has a plurality of through-holes, wherein the salt phase is delivered with pressure as a plurality of dispersed droplets into the continuous lithium phase;

(c) contacting the dispersed droplets of the salt phase with the continuous lithium phase in the reactor for a sufficient time that a fraction of the LiT in the lithium phase passes into the salt phase; delivering the combined lithium and salt phases to a cyclonic hydrocyclonic phase separator;

(e) separating the phases in the cyclonic or hydrocyclonic phase separator to produce an outlet stream of lithium metal having a reduced concentration of LiT and an outlet stream of salt containing a fraction of the LiT that was in the lithium phase at the inlet in step (a). 2. A method according to embodiment 1, further comprising electromagnetically pulsing the extraction column to increase the velocity differential between the heavy salt droplets and the electrically conductive continuous lithium phase.

3. A method according to embodiment 1, further comprising delivering at least a portion of the outlet stream of lithium metal back to the inlet.

4. A method according to embodiment 1, further comprising delivering the outlet stream of lithium metal to the inlet of a second contactor and extracting again with a salt phase containing a molten lithium salt.

5. A method according to embodiment 1, further comprising agitating the salt phase and the lithium phase in the reactor with ultrasonic energy.

6. A method according to embodiment 3, comprising pumping the lithium phase at a rate of 1-20 kg/sec through the inlet

7. A method according to embodiment 6, wherein the rate is 5-10 kg/sec.

8. A method according to embodiment 6, wherein the rate is about 7 kg/sec. 9. A method according to embodiment 3, wherein the concentration of LiT in the lithium phase at the inlet of the reactor is 0.1 to 10 ppm.

10. A method according to embodiment 9, wherein the concentration of LiT is 0.3 to 3 ppm.

11. A method according to embodiment 9, wherein the concentration of LiT is 0.5 to 2 ppm.

12. A method according to embodiment 2, wherein the reactor has a volume of 5-20 m³.

13. A method according to embodiment 2, wherein the lighter phase is fed at a rate of 1-20 kg/sec, the concentration of LiT in the lighter phase is 0.1 to 10 ppm, and the reactor has a volume of 5-20 m³.

14. A method according to embodiment 13, wherein the lighter phase is fed at a rate of about 7 kg/sec, the concentration of LiT in the lighter phase at the inlet to the reactor is about 1 ppm, and the reactor has a volume of about 15 m . 15. A method according to any of embodiments 1 - 14, wherein the lithium salt comprises lithium hydroxide.

16. A method according to any of embodiments 1 - 14, wherein the lithium salt comprises lithium chloride, lithium bromide, or lithium fluoride. 17. A method according to any of embodiments 1 - 14, wherein the lithium salt comprises lithium chloride, lithium bromide, and lithium fluoride.

Claims

We claim:

2. A method according to claim 1, comprising contacting dispersed droplets of the lithium phase with the salt phase in the extraction column and separating the resulting phases in a cyclone or hydrocyclone apparatus of the contactor.

3. A method according to claim 1, comprising contacting dispersed droplets of the salt phase with the lithium phase, and separating the resulting phases in a cyclone or hydrocyclone apparatus of the contactor.

4. A method according to claim 2, comprising introducing molten salt into the extraction column containing molten lithium with dissolved LiT through a distributer plate, whereby dense droplets of molten salt are created that fall under the force of gravity through the lighter molten lithium phase.

5. A method according to claim 4, further comprising emulsifying the salt phase in the lithium phase using ultrasonic energy.

6. A method according to claim 4, further comprising electromagnetically pulsing the lithium phase in the extraction column to provide a body force that works preferentially on the more conductive lithium metal of the lithium phase.

7. A method according to any of the preceding claims, wherein the method is carried out continuously.

8. A method according to any of the preceding claims, comprising a) contacting the phases in a first extraction column b) separating the phases in a first cyclonic or hydrocyclonic phase separator, c) collecting the heavy salt phase from the bottom of the first stage cyclonic or hydrocyclonic phase separator, wherein the salt phase is enriched in lithium, and d) optionally feeding the molten lithium phase containing a reduced level of LiT to a second extraction column and repeating steps a), b), and c).

9. A method according to any of claims 1 - 8, wherein the lithium salt comprises lithium hydroxide or lithium carbonate.

10. A method according to any of claims 1 - 8, wherein the lithium salt comprises lithium chloride, lithium bromide, or lithium fluoride.

11. A method according to any of claim 10, wherein the lithium salt comprises lithium chloride, lithium bromide, and lithium fluoride.

12. A method for extracting LiT from an alpha into a beta phase, wherein the alpha phase comprises LiT and molten lithium metal and the beta phase comprises a molten lithium salt, the method comprising contacting the alpha phase and the beta phase in an extraction column of a non- centrifugal contactor and collecting the beta phase, wherein the beta phase after contacting contains a fraction of the LiT that was present in the alpha phase at the start of the contacting.

13. A method according to claim 12, wherein dispersed droplets of the alpha phase are introduced into the extraction column containing the beta phase as a continuous phase.

14. A method according to claims 12 or 13, wherein dispersed droplets of the beta phase are introduced into the reactor containing the alpha phase as a continuous phase.

15. A method according to any of claims 11-14, wherein the extraction column is disposed in a gravitational field such that a point of introduction of the alpha phase has a lower gravitational potential energy than a point of introduction of the beta phase.

16. A method according to claim 15, wherein the alpha phase coalesces after contact and exits the reactor at the top of the extraction column, and the beta phase coalesces after contact and exits the reactor at the bottom of the reactor.

17. A method according to claims 11-16, further comprising submitting the alpha phase containing a reduced level of LiT after contacting to extraction with another portion of a molten lithium salt, thereby achieving multi-stage separation.

18. A method according to any of claims 12-15, wherein after contact the alpha and beta phase are separated in a cyclonic or hydrocyclonic phase separator

19. A method according to any of claims 12-18, wherein the lithium salt comprises lithium hydroxide or lithium carbonate.

20. A method according to any of claims 12 - 18, wherein the lithium salt comprises lithium chloride, lithium bromide, or lithium fluoride.

21. A method according to any of claims 12-18, wherein the lithium salt comprises lithium chloride, lithium bromide, and lithium fluoride.

22. A method of removing LiT from a lithium blanket to recover tritium for reuse in fabricating targets for an ICF fusion engine, comprising transferring molten lithium containing LiT from the lithium blanket to a non- centrifugal contactor; extracting a fraction of the LiT from the molten lithium into a solvent phase by contacting the molten lithium phase in an extraction column of the contactor with a solvent phase comprising a molten lithium salt; separating the phases after the contacting by gravity or by use of a cyclonic or hydrocyclonic phase separator; recovering the solvent phase containing a fraction of the LiT present in the molten lithium before contacting; and subjecting the solvent phase containing LiT to an electrochemical process to recover tritium for reuse.

23. A method according to claim 22, comprising increasing the interfacial area during contacting of the two phases in the extraction column, increasing turbulence in the reactor to increase the mass transfer coefficient during contacting, sizing the extraction column to provide adequate residence time for the extraction to occur during contacting of the two phases, and consolidating and separating the lithium and salt phases after contact, wherein the contactor has no moving parts.

24. A method according to claim 22, comprising separating the phases in a cyclonic or hydrocyclonic phase separator fluidically connected to the extraction column of the non-centrifugal contactor.

25. A method according to claim 22, comprising increasing the interfacial area through the use of ultrasonic emulsification during the contacting.

26. A method according to claim 22, comprising increasing the interfacial area by providing one or more distributer plates disposed in the flow path of the extraction column to break one or both of the phases into dispersed droplets.

27. A method according to claim 22, comprising increasing turbulence by providing the extraction column with fixed or spinning axial turbulence promoters in a flow channel of the extraction column.

28. A method according to claim 23, comprising increasing turbulence by electromagnetic pulsing of the molten lithium phase in the extraction column, thereby achieving a higher differential velocity between the two phases.

29. A method according to any of claims 22-28, wherein the lithium salt comprises lithium hydroxide or lithium carbonate.

30. A method according to any of claims 22-28, wherein the lithium salt comprises lithium chloride, lithium bromide, or lithium fluoride.

31. A method according to any of claims 22-28, wherein the lithium salt comprises lithium chloride, lithium bromide, and lithium fluoride.

32. A continuous method for extracting lithium tritide from a lighter alpha phase comprising LiT and molten lithium metal into a heavier beta phase comprising a molten lithium salt by contacting the phases during two phase flow in a gravity driven non- centrifugal contactor, comprising

(b) optionally, simultaneously delivering a second feed comprising the rest of the lighter phase into the extraction column to form a continuous alpha phase in the extraction column;

(e) consolidating the lighter phases from the optional first and second feeds in an upper region of the extraction column and drawing off the lighter phase containing a reduced level of LiT from the extraction column as a lithium outlet stream; and

(f) consolidating the heavier phases from optional third and fourth feeds in a lower region of the extraction column and drawing off the heavier phase from the reactor, wherein the heavier phase contains a portion of the LiT present in the lighter phases before the extraction, wherein at least one of the optional first and second feeds is carried out, at least one of the optional third and fourth feeds is carried out, and at least one of the optional first and third feeds is carried out .

33. A method according to claim 32, wherein dispersed droplets of the lighter phase rise through a continuous heavier phase in the extraction column, dispersed droplets of the heavier phase fall through a continuous lighter phase in the extraction column, or both.

34. A method according to claim 33, further comprising electromagnetic ally pulsing the lithium metal in the alpha phase to increase the differential velocity between dispersed droplets and continuous phase.

35. A method according to claim 34, comprising feeding the lighter phase at a rate of 1-20 kg/sec, divided between the second and optional first feeds.

36. A method according to claim 35, wherein the rate is 5-10 kg/sec.

37. A method according to claim 35, wherein the rate is about 7 kg/sec.

38. A method according to claim 34, wherein the concentration of LiT in the second and optional first feeds at the inlet to the extraction column is 0.1 to 10 ppm.

30. A method according to claim 38, wherein the concentration of LiT in the second and optional first feeds is 0.3 to 3 ppm.

40. A method according to claim 38, wherein the concentration of LiT in the second and optional first feeds is 0.5 to 2 ppm.

41. A method according to claim 34, wherein the reactor has a volume of 5-20 m .

42. A method according to claim 41, wherein the lighter phase is fed at a rate of 1-20 kg/sec, the concentration of LiT in the lighter phase is 0.1 to 10 ppm, and the extraction column has a volume of 5-20 m .

43. A method according to claim 41, wherein the lighter phase is fed at a rate of about 7 kg/sec, the concentration of LiT in the lighter phase at the inlet to the extraction column is about 1 ppm, and the reactor has a volume of about 15 m .

44. A multistage process for extracting LiT from a molten lithium phase into a molten salt phase, comprising carrying out the continuous method of claim 32 and delivering the lithium outlet stream as a first or second feed into an extraction column of a second contactor and carrying out steps (a)-(f) with fresh molten lithium salt.

45. A method according to any of claims 32-44, wherein the lithium salt comprises lithium hydroxide or lithium carbonate.

46. A method according to any of claims 32-44, wherein the lithium salt comprises lithium chloride, lithium bromide, or lithium fluoride.

47. A method according to any of claims 32-44, wherein the lithium salt comprises lithium chloride, lithium bromide, and lithium fluoride.

48. A method of removing LiT from a lithium blanket in an ICF fusion engine by extracting a lithium phase containing molten lithium metal and LiT with a salt phase containing a molten lithium salt, comprising:

(c) contacting the dispersed droplets of the salt phase with the continuous lithium phase in the reactor for a sufficient time that a fraction of the LiT in the lithium phase passes into the salt phase;

(d) delivering the combined lithium and salt phases to a cyclonic or hydrocyclonic phase separator;

(e) separating the phases in the cyclonic or hydrocyclonic phase separator to produce an outlet stream of lithium metal having a reduced concentration of LiT and an outlet stream of salt containing a fraction of the LiT that was in the lithium phase at the inlet in step (a).

49. A method according to claim 48, further comprising electromagnetic ally pulsing the extraction column to increase the velocity differential between the heavy salt droplets and the electrically conductive continuous lithium phase.

50. A method according to claim 48, further comprising delivering at least a portion of the outlet stream of lithium metal back to the inlet.

51. A method according to claim 48, further comprising delivering the outlet stream of lithium metal to the inlet of a second contactor and extracting again with a salt phase containing a molten lithium salt.

52. A method according to claim 48, further comprising agitating the salt phase and the lithium phase in the reactor with ultrasonic energy.

53. A method according to claim 49, comprising pumping the lithium phase at a rate of 1-20 kg/sec through the inlet

54. A method according to claim 53, wherein the rate is 5-10 kg/sec.

55. A method according to claim 53, wherein the rate is about 7 kg/sec.

56. A method according to claim 49, wherein the concentration of LiT in the lithium phase at the inlet of the reactor is 0.1 to 10 ppm.

57. A method according to claim 56, wherein the concentration of LiT is 0.3 to 3 ppm.

58. A method according to claim 56, wherein the concentration of LiT is 0.5 to 2 ppm.

59. A method according to claim 49, wherein the reactor has a volume of 5-20 m .

60. A method according to claim 49, wherein the lighter phase is fed at a rate of 1-20 kg/sec, the concentration of LiT in the lighter phase is 0.1 to 10 ppm, and the reactor has a volume of 5-20 m .

61. A method according to claim 60, wherein the lighter phase is fed at a rate of about 7 kg/sec, the concentration of LiT in the lighter phase at the inlet to the reactor is about 1 ppm, and the reactor has a volume of about 15 m .

62. A method according to any of claims 48-61, wherein the lithium salt comprises lithium hydroxide.

63. A method according to any of claims 48-61, wherein the lithium salt comprises lithium chloride, lithium bromide, or lithium fluoride.

64. A method according to any of claims 48-61, wherein the lithium salt comprises lithium chloride, lithium bromide, and lithium fluoride.