A SYSTEM AND METHOD FOR SEPARATION AND PURIFICATION OF DISSOLVED RARE EARTH/PRECIOUS METALS ELEMENTS/COMPOUNDS

Abstract

A method for purification and separation of mixed elements, comprising at least a first free flow electrophoresis separation chamber, wherein a solution of the mixed elements is passed through the first separation chamber, an electric field submitted perpendicular to the solution flow and separating mobile ions of the solution based on electrophoretic mobility. A continuous method comprises selecting a complexing ligand, and controlling the temperature and pH of the solution. Also, a system or method for separating components of a multi-component concentrate comprising directing solution to at least a first and second channel each receiving part of the solution; each channel comprising a concentration section comprising a first transverse electric field across the channel, a fractionation section comprising a second electric field in a direction opposite the first electric field thereby distributing ions of the solution across the channel, and a flow splitter at an output of the fractionation section that divides the flow of each channel into subflows concentrated in heavier elements and concentrated in lighter elements.

Description

FIELD OF THE INVENTION

The present invention relates to a system and a method to separate and refine rare earth/precious metals elements/compounds. More precisely, the present invention relates to a system and method for binary or multicomponent fractional separation and purification of dissolved rare earth/precious metals elements/compounds produced in hydrometallurgical processes while they are dissolved in an acidic or weakly basic medium, without any intermediate precipitation step.

BACKGROUND OF THE INVENTION

Rare earth elements (REE) occur together in nature, and any given mineral contains several or most of them. Production of high purity individual rare earth (RE) elements/compounds from their ores generally requires two stages of processing, including mineral processing and hydrometallurgy.

Mineral processing and hydrometallurgy processing of the ore before REE purification is relatively simple and quite achievable though conventional methods. However, producing individual REE from mixed REs compounds is tremendously tedious. RE processing often requires dozens of steps, each resulting in minute improvement in the complex RE streams. Separating and extracting a single REE requires a great deal of time, resources and expertise. Today, an advanced RE refinery facility cost hundreds of millions of dollars to build.

Most REE are currently extracted in liquid phase using a combination of slightly selective solvent extraction dissolution in organic and aqueous strong acids, which involve a number of cycles. High purity RE concentrates are separated into individual REE using solvent-based (mainly) or ion exchange methods. Although there are several techniques to separate RE, most of them suffer from different types of drawbacks. For instance, solvent extraction requires a great number of cycles to achieve high purity of REE. Techniques using ion-exchanger for separation and refinery operate with low REE concentrations in solution, which leads to very large liquid volume quantity, bulky tanks, dehydrators, pumps and etc.

There is still a need in the art for a system and a method for binary or multicomponent fractional separation and purification of dissolved rare earth/precious metals elements/compounds.

SUMMARY OF THE INVENTION

More specifically, in accordance with the present invention, there is provided a method of purification and separation of mixed elements, using differences between electrophoresis mobility of the elements or coordination complexes thereof in a continuous process, comprising selecting a complexing ligand and forming a solution of the complexing ligand and the mixed elements; controlling the temperature and pH of the solution; and submitting a flow of the solution to an electric field submitted perpendicular to the solution.

There is further provided a system for purification and separation of mixed elements, comprising at least a first free flow electrophoresis separation chamber, wherein a solution of the mixed elements is passed through the first separation chamber, an electric field being submitted perpendicular to the solution flow and separating mobile ions of the solution based on electrophoretic mobility.

There is further provided a multi-channel separation system for purification and separation of elements in a solution, comprising at least a first and a second channels each receiving part of the solution; each channel comprising a concentration section, a fractionation section, and a flow splitter at an output of the fractionation section; the concentration section comprising electrodes that create a first transverse electric field across the channel, and the fractionation section comprising electrodes that create a second electric field in a direction opposite the first electric field across the channel, thereby distributing ions of the solution across the channel; the flow splitter dividing the flow of each channel into a subflow concentrated in heavier elements and a subflow concentrated in lighter elements.

There is further provided a method for separating components of a multi-component concentrate, comprising a) preparing a solution of the multi-component concentrate and a reagent; b) directing the solution to at least a first and a second channel each receiving part of the solution; each channel comprising a concentration section comprising a first transverse electric field across the channel, a fractionation section comprising a second electric field in a direction opposite the first electric field across the channel thereby distributing ions of the solution across the channel, and a flow splitter at an output of the fractionation section that divides the flow of each channel into a subflow concentrated in heavier elements and a subflow concentrated in lighter elements; c) repeating step b) until a target separation of isolated components is achieved; and d) recovering the isolated components.

Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the accompanying drawings

BRIEF DESCRIPTION OF THE DRAWINGS

In the appended drawings:

FIG. 1 is a graph showing separation results of a synthetic REE mixture (La 33%, Eu 33% and Yb 33%) in a free flow electrophoresis system in a single pass;

FIG. 2 is a graph showing separation results of a synthetic REE mixture (La 66%, Eu 17% and Yb 17%) in a free flow electrophoresis system in a single pass;

FIG. 3 is a graph showing separation results of a synthetic REE mixture (La 17%, Eu 17% and Yb 66%) in a free flow electrophoresis system in a single pass;

FIG. 4 is a graph showing separation results of a synthetic REE mixture (Eu 10%, Dy 40%, Tb 40% and Yb 10%) in a free flow electrophoresis system in a single pass;

FIG. 5 is a graph showing separation results of a synthetic REE mixture (La 10%, Nd 40%, Pr 40% and Eu 10%) in a free flow electrophoresis system in a single pass;

FIG. 6 is a graph showing separation results of a synthetic REE mixture (Nd 50%, Pr 50%) in a free flow electrophoresis system in a single pass;

FIG. 7 is a diagrammatic view of a two-step separation of a quaternary REE mixture when the separation in some channels are not complete in a single pass;

FIG. 8 is a graph showing separation results of a synthetic REE mixture (La 10%, Ce 40%, Pr 40% and Eu 10%) in a free flow electrophoresis system;

FIG. 9 is a graph showing separation results of a synthetic REE mixture (Pr 50%, Ce 50%) in a free flow electrophoresis system;

FIG. 10 is a diagrammatic view of a tubular reactor which performs binary ionic fractionation of REE according to an embodiment of an aspect of the present invention;

FIG. 11 is a diagrammatic view of a method of multicomponent REE fractional separation according to an embodiment of an aspect of the present invention;

FIG. 12 is a diagrammatic view of a REE refinery system and method according to an embodiment of an aspect of the present invention; and

FIG. 13 is a diagrammatic view of a chamber used according to an embodiment of an aspect of the present invention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present method and system use electrophoretic mobility variation of REE or precious metals in an electrical field to separate them, thereby reducing the cost of separation and circumventing intrinsic environmental issues of solvent based methods and systems. At the purification stage, the present method and system remove impurities and separate REE/precious metal elements simultaneously. The present method and system will be hereinafter described in relation to REE.

Free flow electrophoresis (FFE) is used to fractionate REE ions, using a uniform electric field applied perpendicular to a solution flow and separating the mobile ions based on electrophoretic mobility (U_i).

Basically, in a FFE system, the translational flow of ions in a laminar flow regime along a channel is affected by a perpendicular electrophoretic force exerted by a static electric field on each ion. The magnitude of this force and hence the deviation of the ions form straight trajectories along the channel, dependent upon the charge to size ratio of each ion, which is expressed as electrophoretic mobility U_i.

The present method and system provide selecting a combination of separation parameters based on the electrophoretic mobility U_i for the separation of elements/compounds.

In the case of REE, as is the case with other properties of REE, the electrophoretic mobility U_i does not vary significantly from one element to another. Typically, REE's U_i values are quite close, ranging from 72.3×10⁻⁵ cm² V⁻¹ s⁻¹ to 67.0×10⁻⁵ cm² V⁻¹ s⁻¹ for Lanthanum and Lutetium for example. Consequently, purification and separation of single REE may appear inefficient in such perspective.

However, the variation between the electrophoretic mobility U_i of REE can be controlled i.e. increased for example, by controlling the temperature and selecting a complexing ligand. The present method and system therefore use an adequate temperature control with a proper complexing agent to improve the electrophoretic mobility U_i variation significantly, for an effective fractionation and separation of REE.

In a first experiment, three triadic synthetic mixtures of non-neighboring REE La, Eu and Yb (1 gr/L total) were prepared in a dilute nitric acid (2% volume) with different REE compositions. These mixtures were separated in a FFE system, at a temperature of about 23° C. using background electrolyte (BGE) containing 10 mM 4-methyl benzyl amine and 4 mM HIBA acting as complexing ligand. The pH was adjusted to 4.4 using diluted acetic acid. The FFE system was a separation chamber 60 cm long, 10 cm wide with an effective separation width of 7 cm, and a 0.2 mm gap width (see FIG. 13). The separation voltage was optimized to 750 V during the experiment. The flow ratio between the REE mixtures, i.e. the analytes, and the BGE was set to 1 to 10. The channels (96 in number) coming out of the FFE system were analyzed with a spectrometer to quantify the metals.

FIGS. 1, 2 and 3 show the REE concentrations at the output of each of the 96 channels of the FFE system. They show that a single pass of the REE mixtures through the chamber allowed perfect separation for those non-neighboring REE in these three triadic synthetic mixtures.

In a second experiment, several synthetic mixtures (1 gr/L) of neighboring REE were separated in the same FFE system as described hereinabove using similar operating conditions as reported in the first experiment.

FIG. 4 shows separation of a quaternary mixture of REE (Yb 10%, Dy 40%, Tb 40% and Eu 10%) in the same method and system as described hereinabove in the first experiment. Except channel 48, which contains both Dy and Tb, all other channels are found to contain pure or zero REE, to the level of detection limit.

FIG. 5 presents separation of a quaternary mixture of REE (La 10%, Nd 40%, Pr 40% and Eu 10%) using the system and method described in the first experiment. The separation of Nd and Pr was complete except for channels 59 to 63 where they overlapped. The solution of these channels requires further separation consequently in a second chamber in order to obtain pure REE.

FIG. 6 depicts binary separation of Nd and Pr, i.e. a second separation stage performed on the outputs of channels 59 to 63 of FIG. 5. Such further separation is needed when a single separation pass is not enough to provide pure REE, especially between neighboring REE. The degree of isolation and purity of each REE at the end of the single-pass separation in the FFE system is determined by the resolution of separation. The separation resolution is measured based upon the concentration of REE at the outlet of a given separation chamber with respect to the feed specification of this chamber. When the degree of isolation or purity of REE is not sufficient in some channels of the FFE system after one stage of separation (i.e. for example channels 59-63 in FIG. 5), a second, consecutive, separation stage is added to the system with the feed thereof connected to those channels of the first previous stage still containing mixed REE. The degree of isolation and purity of REE may thus be improved by adding one, or more, separation step(s), to achieve pure REE, as shown for example in FIG. 6.

For instance, FIG. 7 is a diagrammatic view of a two-step separation of a quaternary REE mixture when the separation in some channels is not complete in a single pass. A mixture of La, Pr, Nd and Eu is fed to the first separation chamber (see left handside). On the outlet of the first separation chamber, the separation in some channels is not complete with Pr and Nd still mixed (i.e. for example channels 59-63 in FIG. 5), while Eu and La and part of Pr and Nd achieve 100% purity. Thus, a consecutive separation chamber is required on those specific channels in order to achieve desired purities of Pr and Nd. As shown in FIG. 7 on the right handside, a second separation chamber is thus added with the feed from those channels containing a mixture of Nd and Pr (i.e. for example channels 59-63 in FIG. 5) at the end of the first separation chamber. The second chamber on the right handside of FIG. 7 allows a complete separation and pure REE at the outlet of the overall system (i.e. for example in FIG. 6).

FIG. 8 is a graph showing separation results of a synthetic REE mixture (La 10%, Ce 40%, Pr 40% and Eu 10%) in the FFE system described hereinbefore; the REE mixture corresponds to another quaternary REE mixture with Ce and Pr as the major neighbors. In this case, some Pr is still present in channels 64 to 69 with Ce in majority. In order to further separate Pr from Ce in these channels, a second pass was added subsequently on those specific channels.

FIG. 9 is a graph showing separation results at the outcome of this second pass It shows that the second pass achieved purification of the Ce/Pr mixture still present at the output of channels 66 to 70 of the first pass to a certain level and that another pass, i.e. a third pass, of separation would further improve the separation between Ce and Pr.

Based on those separation experiments which were performed in a FFE system, i.e. a single channel reactor, a multi-channel separation system 10 is presented for binary separation of REE, as shown in FIG. 10.

In FIG. 10, the system 10 is fed with a mixture of two REE in an aqueous acidic solution. Each channel 12, 14, 16, 18, 20, 22 of the system 10 has been equipped with two sets of electrodes which create transverse electric fields across each channel.

In each channel 12, 14, 16, 18, 20, 22, a first set of electrodes 24, 26, 28, 30, 32, 34, referred to as the concentration electrodes, develops a first electric field that concentrates REE ions in liquid layers flowing close to the wall of the channel, adjacent to the negative plate. In each channel, a second set of electrodes 36, 38, 40, 42, 44, 46, referred to as the fractionation electrodes, applies a second electric field in the opposite direction relative to the electric field created by the first set of electrodes, thus forcing the REE ions to migrate across the channel toward the opposite electrode and eventually fractionating them based on variations in their respective electrophoretic mobility.

As the second electric field distributes REE ions across the channel, concentration profiles of the elements are not identical across and along the channel due to the different mobilities of the REE ions. A flow splitter 48, 50, 52, 54, 56, 58 at the end of each fractionation section divides the flow into two parts, including an upper part and a lower part which have different concentration of each element, heavier elements being more concentrated in the upper part and lighter elements, which migrate faster, being loaded in the lower part.

An electric field of 75 V/cm was selected for both fields in the examples given herein. In practice, it is easier to use identical intensities, but they could be different.

Thus, turning back to FIG. 10, at conjunction A, the main (input) stream is divided into two streams (A1, A2) by an in-line splitter to start a binary separation process in the first two channels 12, 14. Both division streams A1, A2 go through identical fractionation steps as described hereinabove, which yield four subdivision streams B1, B2, B3, B4 at the outlet of the first two channels 12, 14. These subdivision streams B1, B2, B3, B4 are identical two by two, i.e. B1=B3 and B2=B4, in terms of element concentrations. The identical subdivision streams B1/B3 and B2/B4 merge together and are directed through a second fractionation step (from B to C in FIG. 10), in channels 16 and 18 respectively, as described hereinabove. Each fractionation step yields a stream richer of heavier elements and a stream heavier in lighter elements. The same division and merging is performed in conjunction C, identical subdivision streams C1/C3 and C2/C4 merging together and going through a third fractionation step (from C in FIG. 10). The process continues until desired purity of elements is obtained. The number of fractionation steps depends on the concentration of the REE in solution as well as the efficiency of separation: for example closer REE involved in binary separation require a higher number of fractionation steps to reach desired purity, as exemplified for example in the second Experiment described hereinabove.

For multicomponent fractionation, a number of separation units (from A to C in FIG. 10 for example) may be used, each separation unit dividing the components into two groups while keeping the impurities of the first group close to zero in the second group. After a first separation phase, each group may be directed through a subsequent separation phase to be divided into its constituent elements.

FIG. 11 is a diagrammatic view of a separation system for eight REE A to H. for example. In this example, it was assumed that each separation phase (phases I, II, III) is completed after two fractionation steps (Step I/Step II). In practice, the number of fractionation steps depends on the nature of the elements which are to be separated in a given step, as well as their concentrations and the desired target purity. The number of final channels is equal to the number of REE in the original mixture A-H if all the components have to be delivered individually.

The nature of the background electrolyte (BGE), the pH value and the temperature at each separation phase are selected for the ionic REE fractionation in order to optimize the number of fractionation steps per separation phase. Also, the number of fractionation steps and of separation phases, i.e. the size of the system, depend, as mentioned hereinabove, on the electric field intensity, the residence time of the ions in the electric field and the REE concentrations.

For instance, a mixture of 1 gr/L REE ions is separated using a BGE comprising 10 mM 4-methyl benzyl amine and 4 mM HIBA, which forms a complexing agent at pH of 4.4, i.e. for example in an acetic acid solution, at a temperature of 23° C., under an electric field of 75 V/cm, in a 4 to 5 minutes residence time.

The flow ratio between the REE mixtures, i.e. the analytes, and the background electrolyte BGE is adjusted depending on the nature of the mixtures and the other operating conditions.

The temperature is generally selected in the range between 5 and 70° C., for example between 15 and 25° C., for a pH between 2 and 10, for example between 3 and 6, and a flow ratio between the REE mixtures, i.e. the analytes, and the background electrolyte BGE in a range between 1/100 and 1/3, for example between 1/10 and 1/3. The ligand or complexing agent concentration, given as molar ratio of total ligands to total metal ions, is selected in a range between 1/1 and 10/1, for example between 2/1 and 5/1.

The electrodes that generate the electric fields within the channels may be conductive plates connected to a DC power supply. The electrodes may be inserted into the walls of the channels in direct contact with the liquid flow. Alternatively, they may be positioned outside of the channels, inducing electrostatic field into the solution flowing inside.

The electric field intensity is selected according to the concentration and mobility differences between the REE which are to be separated at each phase.

The separation channels or chambers can comprise semi-permeable membranes, such as Nafion® for example, which are conductive to protons (H⁺) and hydroxyl (OH⁻) and obstruct metallic ions and their complexes, thereby to preventing metal ions to reach the electrodes in case the electrodes are positioned in direct contact with the liquid flow.

The REE separation output is in ionic form. Then, pure REE may be recovered from the solution in any desired solid form (i.e. carbonate, hydroxide, oxide . . . ).

FIG. 12 is a diagrammatic view of a separation method and system which integrate a multi-component separation method and system of the present invention. A REE concentrate is introduced in form of RE-oxide, RE-chloride, RE-nitrate or RE-hydroxide (step 60). Reagent 61, 62 is added to this feed and homogenized properly (step 63). A pump 64 sends the resulting RE solution into a multi-component separation system 65 as described hereinabove. A stream of impurities and rejected REs 77 is diverted to a purification unit 67 (step 66). Isolated REE leave the separation reactor 65 in multiple channels as described hereinabove (step 68). In a REE precipitation unit 69, these isolated REE are recovered in form of Re(OH)₃ or Re₂CO₃ from the liquid phase separately 70, 71, 72, 73.

The depleted solutions from the REE precipitation unit 69 (step 74) and from the purification unit 67 (step 75) are then processed in a regeneration unit 76 to be recycled as a recycled reagent 61. Indeed, the complexing agent in FFE separation (i.e. 4-methyl benzyl amine and HIBA in acetic acid solution as described hereinabove) is the reagent in the overall process. This reagent is regenerated and recycled after separation in order to keep the process sustainable and feasible. However, since the regeneration of any reagent is limited to a certain efficiency, a make-up stream of reagent 62 may be needed.

This separation method and system allow replacing most of the multiple, complex chemical transformations usually required to separate and purify REE. They greatly reduce costs, time, and usage of a variety of chemical reagents that could produce environmental and safety problems. Capital costs are greatly reduced compared to the all-chemical methods and systems currently being used.

Although the method and system were described hereinabove for use in separating REE from each other, they may be used in other hydrometallurgical methods for either concentrating or rejecting element/compound. In the latter case, they could be used to remove impurities directly from the solution without the need for filtration and rewashing methods that result in valuable element/compound losses and dilution of streams containing the values sought.

Although the present invention has been described hereinabove by way of embodiments thereof, it may be modified, without departing from the nature and teachings of the subject invention as described.

REFERENCES

• Kasicka, V., 2009, From micro to macro: Conversion of capillary electrophoretic separations of biomolecules and bioparticles to preparative free-flow electrophoresis scale: Electrophoresis, v. 30, p. S40-S52.
• Santoyo, E., R. Garcia, K. A. Galicia-Alanis, S. P. Verma, A. Aparicio, and A. Santoyo-Castelazo, 2007, Separation and quantification of lanthanides in synthetic standards by capillary electrophoresis: A new experimental evidence of the systematic “odd-even” pattern observed in sensitivities and detection limits: Journal of Chromatography A, v. 1149, p. 12-19.

Claims

1. A method of purification and separation of mixed elements, using differences between electrophoresis mobility of the elements or coordination complexes thereof in a continuous process, comprising:

selecting a complexing ligand and forming a solution of the complexing ligand and the mixed elements;

controlling the temperature and pH of the solution; and

submitting a flow of the solution to an electric field submitted perpendicular to the solution.

2. The method of claim 1, wherein said selecting the complexing ligand comprises selecting the complexing ligand with a concentration in a range between 1 μmol/L and 1 mol/L.

3. The method of claim 1, comprising controlling a flow ratio between the mixed elements and the complexing ligand in a range between 1/100 and 1/3.

4. The method of claim 1, comprising controlling a flow ratio between the mixed elements and the complexing ligand in a range between 1/10 and 1/3.

5. The method of claim 1, comprising controlling the concentration of complexing ligand in a range between 1/1 and 10/1.

6. The method of claim 1, comprising controlling the concentration of complexing ligand in a range between 2/1 and 5/1.

7. The method of claim 1, wherein the complexing ligand comprises 10 mM 4-methyl benzyl amine and 4 mM HIBA.

8. The method of claim 1, wherein said controlling the temperature comprises controlling the temperature in a range between 5 and 70° C.

9. The method of claim 1, wherein said controlling the temperature comprises controlling the temperature in a range between 15 and 25° C.

10. The method of claim 1, wherein said controlling the pH comprises controlling the pH in a range between 2 and 10.

11. The method of claim 1, wherein said controlling the pH comprises controlling the pH in a range between 3 and 6.

12. The method of claim 1, wherein the mixed elements are mixed rare earth elements or mixed precious metals.

13. A system for purification and separation of mixed elements, comprising at least a first free flow electrophoresis separation chamber, wherein a solution of the mixed elements is passed through the first separation chamber, an electric field being submitted perpendicular to the solution flow and separating mobile ions of the solution based on electrophoretic mobility.

14. The system of claim 13, comprising at least a second separation chamber, said second separation chamber being in series and/or in parallel with the first separation chamber for fractionation and refinery of metallic ions at the output of the first separation chamber.

15. A multi-channel separation system for purification and separation of elements in a solution, comprising at least a first and a second channels each receiving part of the solution;

each channel comprising a concentration section, a fractionation section, and a flow splitter at an output of the fractionation section;

said concentration section comprising electrodes that create a first transverse electric field across the channel, and said fractionation section comprising electrodes that create a second electric field in a direction opposite the first electric field across the channel, thereby distributing ions of the solution across the channel;

said flow splitter dividing the flow of each channel into a subflow concentrated in heavier elements and a subflow concentrated in lighter elements.

16. The system of claim 15, further comprising a connection merging the subflows concentrated in heavier elements from the first and second channels, and a connection merging the subflows concentrated in lighter elements from the first and second channels.

17. The system of claim 15, further comprising a connection merging the subflows concentrated in heavier elements from the first and second channels, and a connection merging the subflows concentrated in lighter elements from the first and second channels;

further comprising a third and a fourth channels, the third channel receiving the merged subflows concentrated in lighter elements and said fourth channel receiving the merged subflows concentrated in heavier elements;

each one of the third and fourth channels comprising a concentration section, a fractionation section, and a flow splitter at an output of the fractionation section;

said concentration section comprising electrodes that create a first transverse electric field across the channel, and said fractionation section comprising electrodes that create a second electric field in a direction opposite the first electric field across the channel, thereby distributing ions of the solution across the channel;

said flow splitter dividing the flow of each channel into a subflow concentrated in heavier elements and a subflow concentrated in lighter elements.

18. The system of claim 15, wherein the first electric field concentrates metallic ions or complexes to a first wall of the respective channel along the flow direction, and the second electric field forces the metallic ions or complexes to migrate across the respective channel to an opposite wall of the respective channel.

19. The system of claim 15, wherein each channel comprises semi-permeable membranes preventing ions to reach the electrodes.

20. A method for separating components of a multi-component concentrate, comprising:

a) preparing a solution of the multi-component concentrate and a reagent;

b) directing the solution to at least a first and a second channel each receiving part of the solution; each channel comprising a concentration section comprising a first transverse electric field across the channel, a fractionation section comprising a second electric field in a direction opposite the first electric field across the channel thereby distributing ions of the solution across the channel, and a flow splitter at an output of the fractionation section that divides the flow of each channel into a subflow concentrated in heavier elements and a subflow concentrated in lighter elements;

c) repeating step b) until a target separation of isolated components is achieved; and

d) recovering the isolated components.

21. The method of claim 20, further comprising diverting a stream of impurities and rejected components to a purification unit.

22. The method of claim 20, further comprising processing a depleted solution from the recovery of the isolated components to a regeneration unit to yield a recycled reagent for use in step a).

23. The method of claim 20, further comprising diverting of impurities and rejected components to a purification unit, and further comprising processing at least one of: i) a depleted solution from the recovery of the isolated components and ii) a depleted solution from the purification unit to a regeneration unit to yield a recycled reagent for use in step a).