The present invention provides systems and methods for efficient extraction of lithium from brines, particularly high salt brines containing significant concentrations of sodium (Na/Na+), potassium (K/K+), magnesium (Mg/Mg2+), calcium (Ca/Ca2+), chloride (Cl/Cl−), sulfate (SO4/SO42−), boron (B, ionic or molecular) and/or other ions that can lead to lithium (Li/Li+) losses in new and existing processes for Li extraction from brine due to Li co-precipitation with such other ions. As a result of the systems and methods taught herein, significantly higher concentrations of lithium are possible, which is a significant benefit to the precipitation plant operations. The preferred systems and methods herein also require limited resources in terms of energy and water inputs and can recycle impurity ions back into the systems and methods so that they can be efficiently removed, resulting in surprisingly high yields of lithium from complex brines.
Nearly two-thirds of the lithium resources in the world reside in very high salinity brines with lithium concentrations ranging from 200 ppm-2000 ppm. Lithium in these brines is typically subterranean and associated with high levels of Na+, K+, Mg2+, Ca2+, Cl−, SO42−, B (ionic or molecular) and other ions (i.e., “impurity ions”). Each brine chemistry is unique. However, lithium-containing brines are broadly classified into high magnesium and high sulfate brines. Typical brine compositions from several major lithium producing regions are shown in Table 1.
Existing methods and systems for extracting lithium from brines are based on solar evaporation/concentration processes. In all such cases, major co-precipitation losses of lithium occur during evaporation and concentration processes. In high magnesium brines, these losses occur mainly as a lithium carnallite precipitate (LiCl·MglCl2·7H2O). In high sulfate brines, these losses occur mainly as lithium sulfate monohydrate (Li2SO4·H2O) and lithium schoenite (Li2SO4·K2SO4) precipitates. Losses of 40-70% of the valuable lithium resource occur because much of the lithium is sacrificed by co-precipitation to attain target lithium concentration.
Moreover, the known evaporation and concentration processes are typically accomplished using large solar evaporation ponds having a significant environmental footprint. Sub-surface brine and associated water is pumped to the surface for evaporation. A typical evaporation and concentration process is depicted in
Solutions to reduce the environmental footprint of lithium extraction are needed. The nearly universal approach is to selectively separate lithium from the feed well brine using nanofiltration, ion sorption, ion exchange, and/or electrodialysis processes. These methods also have significant limitations because the volumes of brine that must be treated are very large due to the low concentrations of lithium at this stage. Technologies like nanofiltration also cannot operate at the high levels of total dissolved solids in these brines, thus requiring a high degree of dilution with water to make nanofiltration separations possible. Water is a very scarce resource, particularly in arid regions, which leads to other socio-environmental impacts, in addition to further diluting the brines instead of concentrating them. In addition, nanofiltration and reverse osmosis processes require high pressures which represent a major operating cost. Shortcomings of ion exchange and ion sorption processes reside in the limited selectivity and specific capacities offered. These are also batch processes and require chemicals for elution of ions and large amounts of water for washing the resin or media beds. Disposal of this contaminated effluent is another problem. And, for conventional electrodialysis applications, moderate selectivity membranes against a very high background of impurities results in excessive current and energy requirements to move the impurity ions along with lithium.
To address the shortcomings of the conventional approach as well as the newer approaches, systems and methods are needed that can eliminate or minimize lithium co-precipitation losses. Such systems and methods should ideally only require treatment of a small portion of the original brine, thus improving the economics of lithium production in a socio-environmentally sustainable fashion.
We have found that conventional extraction of lithium from brines results in significant losses of lithium in the evaporation stages due to adhering brine losses with undesirable precipitated salts and as lithium co-precipitation losses. For example, when a salt such as NaCl precipitates early in the process, it must be harvested and removed from the ponds to keep the ponds available for further incoming brine. The harvested NaCl solid is not completely dry and there is adhering liquid with it. This liquid has the same chemistry as the brine in the pond and as such also contains lithium. This lithium is hence lost. These types of losses are referred to as adhering brine losses. Co-precipitation losses are when a lithium salt solid precipitates as itself or as a double salt with other cations and anions. This is the co-precipitation loss. Lithium co-precipitation losses from such processes can be as large as 40-60%, depending on the specific process and brine chemistry.
The systems and methods described herein can eliminate the lithium co-precipitation losses by application of a separator at a specific location(s) in the evaporation sequence. Applications of the systems and methods provided herein can be seamlessly incorporated into existing operations or be utilized as design features in new operations. Advantageously, the preferred systems and methods increase lithium recovery by absolute 10-80%, and thus greatly reduce lithium extraction costs and environmental impact.
In one embodiment, the present disclosure provides a system for efficiently extracting lithium from brines by reducing lithium losses due to co-precipitation and/or allowing significantly higher lithium concentration. The preferred system includes a sequence of two or more solar evaporation ponds configured to allow evaporation of brine to occur in each pond and for brine to flow from a first pond to one or more other ponds in the sequence; and a conduit configured to remove at least a portion of the brine at a brine removal location and transmit the removed brine to a separator whereby one or more impurities are separated from lithium to form a high impurity stream (i.e., the impure stream) and a low impurity stream (i.e., the pure stream). The high impurity stream is optionally recycled to the sequence of evaporation ponds at a location the same as or upstream from the brine removal location and the low impurity stream is fed to one or more of the removal location, to a subsequent pond in the sequence, or to a lithium plant or concentration facility. The brine removal location is positioned such that lithium co-precipitation together with the one or more impurities is reduced as compared to an amount of lithium co-precipitation that would occur in the preceding or succeeding ponds in the absence of the separation system. As a result, lithium loss due to co-precipitation is reduced or eliminated. It will be understood that the low impurity stream may have a higher or lower concentration of lithium than the high impurity stream but will have a lower concentration of the one or more impurities that are selected for separation from lithium in the separator. By “impurities” herein, we mean components such as Na+, K+, Mg2+, Ca2+, Cl−, SO42−, B (ionic or molecular) and other ions (i.e., “impurity ions”) or components that, unless separated and/or removed, can form co-precipitates with lithium.
In one case the present disclosure provides a system wherein feed to a first pond in the sequence of ponds is a high lithium, low sulfate brine (e.g., Chilean-type) brine. In a preferred embodiment of this case, the high impurity stream is recycled to a pond precipitating a salt selected from the group consisting of bischofite and carnallite and the low impurity stream is fed to a pond that is substantially free of co-precipitated Li in the form of lithium carnallite.
In another case, the present disclosure provides a system wherein feed to a first pond in the sequence of ponds is a low lithium, high magnesium, high sulfate (e.g., Bolivian-type) brine. In a preferred embodiment of this case, the high impurity stream is recycled to a pond precipitating a salt selected from the group consisting of bischofite, carnallite, hexahydrite and kieserite, and the low impurity stream is fed to a pond that is substantially free of co-precipitated Li in the form of lithium sulfate monohydrate.
In another case the feed to a first pond in the sequence of ponds is a low lithium, low magnesium, high sulfate (e.g., Argentinian-type) brine. In a preferred embodiment of this case, the high impurity stream is recycled to a pond precipitating a salt selected from the group consisting of NaCl and Glauber's salt, and the low impurity stream is fed to a pond that is substantially free of co-precipitated Li in the form of lithium potassium double salt or lithium schoenite.
In any of the embodiments in the preceding paragraphs, the high impurity stream is evaporated in a separate pond sacrificing the contained lithium or harvesting precipitated lithium salt for further processing. The high impurity stream could also be reinjected to the aquifer. The low impurity stream can be processed as described in paragraphs [0010] to [0012] or taken directly to precipitation or downstream processing plant either together with the concentrated brine or separately from it.
In one aspect of the systems and methods herein the portion of brine removed at the brine removal location is preferably 1% to 100%, 5% to 100%, 25% to 100%, or 50% to 100% of the total brine flow in the ponds. In another aspect, the increase in lithium recovery is from about 10 to about 80% (absolute units).
In another aspect of the systems and methods herein, the lithium containing brine is pre-concentrated by solar evaporation to a point at the brine removal location at which further concentration would co-precipitate lithium salts. Preferably, the separator is configured to at least partially separate lithium from impurity cations and anions which have a propensity to form lithium salts that can precipitate under further brine concentration, and which impurity cations and anions are suitable for earlier precipitation with each other in preceding evaporation ponds in the sequence. The separation may be, for example, selected from the group consisting of a selective ion separation membrane, nanofiltration, ion sorption, ion exchange, and electrodialysis. A particularly preferred separator is a LiTAS™ selective ion separation membrane. The membrane separator can be operated in a dialysis or electrodialysis mode.
In another embodiment, the present disclosure provides a system further including removal of borate ions or boric acid in the separation process and recycling and precipitating borate ions or boric acid in previous ponds in the sequence as calcium borate or boric acid, thereby eliminating or substantially reducing a potential requirement for further boron treatment.
In another aspect, the systems provide for recycle of the high impurity stream to a point in one or more preceding evaporation ponds in the sequence where conditions are favorable for precipitation and thus removal of one or more impurity ions without lithium co-precipitation. In another aspect, the systems provide for advancing the low impurity stream to a downstream pond, mechanical evaporator, or precipitation plant for further concentration. This further concentration can now occur substantially without lithium co-precipitation and the associated lithium loss.
In another aspect, the systems provide for the high impurity stream diverted to a separate pond for evaporation or re-injection into the aquifer. Precipitated salts containing lithium could be processed together or separately with the brine in the processing plant. In another aspect, the systems provide for advancing the low impurity stream directly to the downstream processing plant.
In a further embodiment, the present disclosure provides a method for improving efficiency in extracting lithium from brines using a sequence of solar evaporation ponds, by reducing lithium losses due to co-precipitation, the method including separating at least a portion of the brine at a brine removal location to obtain a removed brine, and transmitting the removed brine through a separator such that one or more impurities are separated from lithium to form a high impurity stream (e.g., the impure stream) and a low impurity stream (e.g., the pure or, at least, increased purity stream). The method can next recycle at least a portion of the high impurity stream to the sequence of evaporation ponds at a location the same as or upstream from the brine removal location, and transfer the low impurity stream to one or more of the removal location (i.e., the pond from which the brine was removed), to a downstream (i.e., subsequent) pond in the sequence, or to a lithium recovery facility. The brine removal location is positioned such that lithium co-precipitation with one or more impurities is reduced from the brine flow and higher concentration of lithium is attained due to lithium co-precipitation reduction or elimination. The method may include further concentrating the low impurity stream by, such as, evaporation without co-precipitation loss of lithium even at higher concentrations.
In one aspect, the method of separating is conducted via a selective monovalent-multivalent and/or a monovalent-monovalent ion separation system. Preferably, the separator comprises a LiTAS™ Technology Membrane. The membrane may be operated in a dialysis or electrodialysis mode.
In other aspects, the method of separating is conducted via a solvent extraction, ion exchange or ion adsorption technique to selectively separate lithium from impurity ions.
In one aspect, the method can attain an increase in lithium concentration in a range from about 50% to about 400%.
These and other embodiments are illustrated herein below and described in the appended claims.
So that the manner in which the features, advantages and objects of the invention, as well as others which may become apparent, are attained and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiment thereof which is illustrated in the appended drawings, which drawings form a part of this specification. It is to be noted, however, that the drawings illustrate only example embodiments of the invention and is therefore not to be considered limiting of its scope as the invention may admit to other equally effective embodiments.
The methods and systems of the present disclosure can now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The methods and systems of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure can be thorough and complete, and can fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout.
The systems and methods described herein advantageously eliminate or minimize lithium co-precipitation losses by application of a separator, preferably a selective monovalent-multivalent and/or a selective monovalent-monovalent separation process applied at a selected location in the evaporation cycle.
In general, the methods comprise one or more of the following steps: solar evaporation to preconcentrate the brine to the point of lithium saturation; apply selective separation to separate lithium from the impurities at a selected location (preferably, a point such that lithium would otherwise reach saturation and co-precipitation with impurity ions); return separated impurities to a location in the evaporation sequence where conditions are favorable for their precipitation; and then further concentrate lithium by, such as evaporation, as the accompanying impurities do not favor lithium co-precipitation.
With reference to solar evaporation, to preconcentrate the brine to the point of lithium saturation, in addition to the use of solar energy for evaporation, the resulting salt precipitations are effective methods for removing undesirable impurities from the brine while concentrating the brine's lithium content. This naturally occurring process is superior to most energy intensive mechanical separations. The rejections of undesirable impurities from solar evaporation are shown in Table 2. Hence, instead of attempting to mechanically separate these impurities from the as-pumped brine, in one embodiment natural evaporation-concentration-precipitation processes are allowed to occur to, at, or near the point of lithium saturation, the “saturation point.” For example, this point may be reached after the carnallite/bischofite pond as shown in
With reference to selection of advantageous location(s) for separation of lithium from impurities, we have found that the location depends on which lithium salts precipitate at what point in the evaporation sequence and also the conditions prior to this point of lithium precipitation which are favorable for precipitating other salts. Selection of locations for application of separation can also be viewed as a location for removal of a portion of the brine stream from the sequence of evaporation ponds. This location is preferably a point at which the concentration of lithium is within a range of minus 50%, minus 25%, preferably plus or minus 10%, or up to plus 50% of its saturation concentration in the brine. This point also reflects a potential limit on the location of recycle for return of impurities to the existing ponds where conditions are favorable for their precipitation and removal. The recycle location can be at the location for removal (e.g., the same pond from which removal occurred) of at least a portion of the brine stream or can be upstream of this location (e.g., a prior evaporation pond in the sequence of ponds) where conditions are favorable for precipitation of impurities without lithium co-precipitation, or a separate pond for partial or total evaporation or re-injected to the aquifer. Such recycle and precipitation of the impurities prevents them from building up in the system and altering the chemistry in the evaporation ponds.
By way of illustration, three scenarios are shown in
In the scenario of
In
As illustrated in
In addition, in all the cases an optional separator configured to block the borate anion from advancing and thus recycling it back to the previous ponds where conditions are favorable for precipitation of calcium or sodium borate or boric acid also is beneficial. Conventionally, boron is removed from the concentrated brine by expensive and environmentally undesirable methods, such as solvent extraction using organic solvents.
If however the pH is acidic, as it is in all cases with such brines and electrodialysis is used as the separation device, boron existing as molecular boric acid follow water and is essentially retained with the impurity rich stream and precipitated in the preceeding ponds. This alleviates the necessity of the boron removal step in or in between the evaporation ponds and the processing plant.
Similarly, any solvent extraction, ion exchange or ion sorption process that retains boron with the impurity rich stream will benefit from this approach as described in the preceding paragraph.
As shown in
By references to “Chilean-type,” “Bolivian-type”, and “Argentinian-type” brines herein, we mean brines having the ratios of components as shown in Table 3, plus or minus 50%, plus or minus 30%, or preferably plus or minus 15% of the following ratios.
It should be understood that separators useful in embodiments of the present disclosure can include any separators which can achieve separation of at least a portion of lithium from one or more impurities in the brine, and preferably targeted monovalent-monovalent and/or monovalent-multivalent separations. Examples of suitable separators utilize nanofiltration, ion sorption, or ion exchange, with preferred embodiments utilizing LiTAS™ membrane separation technology as shown in
Dialysis mode is suitable for ionic separation subsystems herein as very low energy costs are incurred as the transfer of ions through the membranes relies on concentration driving forces rather than electrical or pressure driving forces. At the ultra-high salinity of the brine solutions (50-60% Total Dissolved Solids, TDS) osmotic pressures are too large to be overcome by practical or economically feasible means. A reasonable degree of selectivity, particularly monovalent-monovalent cationic selectivity (Li+—Na+, K+), is also desired along with high throughputs.
In a dialysis mode membrane operation, Li extraction is conducted in a source of fresh water or a low Li-containing water source to maintain a suitable concentration gradient across the membrane. The extractant or sweep fluid may also advantageously constitute return mother liquor from the downstream precipitation plant which is low in lithium and high in Na and Cl. High Na concentration may also enhance monovalent-monovalent selectivity between Li and Na, as the concentration driving force for Na would be lower.
A dialysis approach would slightly reduce the lithium concentration compared to the feed to the separator. This can be overcome by application of electrodialysis to selectively concentrate lithium or by reverse osmosis to reject water. The TDS of the pure stream is around 10% which can allow a small concentration using reverse osmosis before osmotic pressures become too large.
An electrodialysis mode of operation with Li-selective membranes is particularly preferred as fresh water use is minimized, and the process stream can be cleaned and concentrated simultaneously. In addition, molecular boric acid in acidic conditions remains with the impurity stream allowing its simultaneous removal with other impurities rather than needing a separate step for its removal.
Other separation technologies could be the well-known solvent extraction, ion exchange or ion sorption where lithium is selectively separated from impurities and boron remains with the impurity concentrated stream.
As illustrated in
As shown and discussed above, the separators advance lithium forward and recycle the impurities to the preceding ponds. The return location of the impurities is preferred to be the same pond from which the feed to the separator is drawn. This can however also be recycled to earlier stages of evaporation if the chemistry is favorable for ion impurity precipitation is such ponds. The impurities could also be evaporated partially or completely in a separate pond or injected to the aquifer. The lithium advance stream could be concentrated during separation such as with electrodialysis or other separation methods and advance directly to the downstream processing plant.
Referring to
New ponds and evaporation concentration systems can also be designed to incorporate aspects of the presently disclosed systems and methods in new operations. The impurities-depleted brine from the separator can advance normally to the next pond in the series where lithium concentration can increase significantly without co-precipitation as double salts with impurities.
These and further aspects of the systems and methods are described below in relation to exemplary embodiments which include examples that both illustrate the use of the systems and methods and provide corresponding characterization data relating to ions removed and Li recovery efficiency. Having described currently preferred embodiments of systems and methods, and having shown illustrative details of particular embodiments, it will be understood that the specific examples given below are employed in a descriptive sense only and are not for the purpose of limitation. Various modifications to the embodiments may be made without departing from the spirit and scope of the present invention which is limited only by the appended claims.
The currently preferred systems and methods were modelled using simulation software through the entire evaporation sequence of the ponds. An Extended UNIQUAC thermodynamic modelling approach was used to predict thermodynamic equilibrium. This model has been validated previously in lithium and non-lithium aqueous chemistry applications from a variety of sources. The model provided brine compositions through the progressive evaporation stages precipitating different phases of salts. Modelling was conducted at a steady state at a fixed temperature of either 5° C. (Argentinian type brines) or 10° C. (Chilean and Bolivian type brines).
As evaporation proceeds, the first salt to precipitate is halite followed by sylvinite (mixture of halite and sylvite), kainite, calcium borate and gypsum. Further evaporation precipitates carnallite, bischofite, kainite, sylvinite, gypsum, kieserite and boric acid. The precipitation of salts varies and is dependent on the starting brine compositions and evaporation conditions. This proceeds until a lithium concentration of about 0.5-2% is reached. Further evaporation from this level starts precipitation of lithium sulfate monohydrate, lithium carnallite or lithium schoenite, again dependent on the brine composition, potentially resulting in significant lithium losses from prior systems.
Equilibrium concentrations of all ionic species were obtained from the thermodynamic model and used in a mass balance simulation. The equilibrium concentrations controlled the precipitation of different salts in this model and advanced the brine from one stage to the next. Separator selectivities as shown in Table 4 were programmed into the model to generate pure and impure streams from the separator. In Examples A and B, the impure stream was returned to the pond from which the separator feed was drawn. In Example C, the impure stream was returned to the first pond in the evaporation sequence. The model was iterated until a steady state was obtained in the ponds and the separator. Under the new steady-state brine chemistry of the ponds, equilibrium parameters were recalculated and the model re-iterated. The pure stream from the separator was concentrated in the next pond in a similar fashion. The result was a full profile of brine and precipitated solids compositions and flow across the entire evaporation sequence of the Examples.
These simulations were conducted for three known brine sources from Chile, Bolivia and Argentina. Single pass transfer to the pure stream was set at 10% in Example A, 90% in Example B and 84% for Example C. Example B also utilized a two-stage separation where the lithium rich stream after the first stage undergoes another separation step to further clean that stream in a second stage. Example A represents monovalent selective membrane dialysis, Example B monovalent selective membrane electrodialysis and Example C a lithium selective membrane dialysis process. These variations between the examples have been shown to demonstrate the applicability of the method taught here to any such appropriate technology or separation. Results are presented in the three examples below. Simulations were conducted both for the conventional brine evaporation process and the process incorporating a preferred system and method as taught in this disclosure. Simulation results of Examples A and C represent existing or proposed operations. The results for the conventional process as practiced match closely with actual operations. This also confirms the validity of our modelling and simulation approach for these and other applications and examples.
As seen in this example, the starting lithium brine concentration is high at 0.19%. The Mg/Li ratio is moderately low at 6.6. Sulfate is low at 0.2%. Upon evaporation in Pond I, the major precipitate is halite (NaCl). Pond II precipitates NaCl and KCl (sylvinite) in major amounts. In Pond III, conditions are favorable for precipitation of magnesium as bischofite (MgCl2·6H2O) and carnallite (KCl·MgCl2·6H2O). These conditions are exploited in this Example to recycle additional magnesium and precipitate the same. Lithium concentration after this pond reaches 1.65%. This point was determined such that any concentration beyond this will result in lithium co-precipitation. As seen, by comparison, further evaporation starts to precipitate lithium and magnesium together as lithium carnallite (LiCl·MgCl2·7H2O) resulting in large lithium losses.
Hence, the point of application for the separator was determined. The separator would be applied after Pond III and before Pond IV as lithium precipitation and losses do not occur in Pond III but start in Pond IV. The co-precipitating element of interest is also now determined to be Mg as lithium co-precipitates with magnesium in Pond IV. A suitable location to remove this magnesium is also now known to be Pond III where conditions are favorable to precipitation of magnesium but not lithium.
As shown in
The mass balance and simulation results after application of the separator at the selected location is shown in
As shown in
As seen in this example, the starting lithium brine concentration is very low at 0.07%. The Mg/Li ratio is very high at 19. Sulfate/Li ratio is also very high at 29. Upon evaporation in Pond I, the major precipitate is halite (NaCl) and polyhalite (K2SO4·MgSO4·2CaSO4·2H2O). Pond II precipitates NaCl+KCl (Sylvinite) and minor amounts of polyhalite. In Pond III, halite, sylvinite, kainite (KCl·MgSO4·3H2O) and carnallite (KCl·MgCl2·6H2O) precipitate. Here, Li concentration reaches 0.49%. Further evaporation in Pond IV starts lithium sulfate monohydrate precipitation along with increasing amounts of carnallite and other salts.
The preferred point of application for the separator is thus selected. The separator would be applied after Pond III and before Pond IV as lithium precipitation and losses do not occur in Pond III but start in Pond IV. The co-precipitating ion of interest is also now determined to be sulfate as lithium precipitates as Li2SO4·H2O in Pond IV. The separation used here grossly separates all impurities from Li. A suitable location to remove this sulfate ion is also now known to be Pond III as it is already precipitating Mg, K and sulfate as carnallite and kainite and boric acid, but not lithium. Magnesium is the counter-ion to sulfate that is selected in this Example as sulfate precipitates with magnesium in the preceding ponds.
Simulation and modeling of this new flowsheet as shown in
With the application of the preferred method, the recoverable lithium would almost quadruple as seen by comparing Streams 13 in
As shown in
The brines in this Example are Argentinian type brines which are characterized by low Li and Mg contents but high sulfate.
As seen in this Example, the starting lithium brine concentration is very low at 0.07%. The Mg/Li ratio is also very low at ˜3. Sulfate/Li ratio is however very high at 20. Upon evaporation in Pond I, the major precipitate is halite (NaCl) along with Glauber's salt (Na2SO4·10H2O). Pond II continues to precipitate halite. Pond III precipitates halite and sylvite (Sylvinite, NaCl+KCl). These ponds also precipitate minor amounts of syngenite (K2SO4·CaSO4·H2O). Hence it can be seen that the major sink to remove the high levels of sulfate in this brine type is in Pond I.
Pond III reaches a lithium concentration of 0.69%. Further concentration beyond this in Pond IV results in lithium co-precipitation losses as lithium potassium double salt (lithium schoenite, Li2SO4·K2SO4). Hence, the selected location for the separator application would be after Pond III. It is also now determined that reducing sulfate levels along with an associated counter-ion such as K or Na would prevent lithium co-precipitation losses in Pond IV. A suitable sink for sulfate was already determined to be Pond I. Hence, recirculating the impure sulfate concentrated stream from the separator to Pond I, would remove the excess sulfate. A separator was modelled at the selected location, achieving monovalent-monovalent and monovalent-multivalent separation with selectivities as shown in Table 5.
As shown in
The pure stream from the separator proceeds normally to Pond IV. Here, evaporation can proceed without any co-precipitation of lithium due to the low levels of sulfate. Lithium concentration can now reach 1.95% before co-precipitation of lithium would begin. In the conventional case, lithium concentration without co-precipitation losses would only reach 0.69%.
As shown in
In another embodiment of this invention, a separator can be used in conjunction with one or more evaporation ponds in different arrangements as shown in
The term “brownfield” or brownfield operation as used herein refers to a lithium brine project that has at least one equipment installed at the facility or an evaporation pond-based lithium or lithium compounds production process. The term “greenfield” or greenfield operation as used herein refers to a lithium brine project that does not have any equipment installed at the facility. The term “moderate recovery” as used herein refers to lithium recovery of about 30-70%. The term “low feed concentration” as used herein refers to 30-100 ppm Li, the term “medium feed concentration” refers to 100-400 ppm Li, and “high feed concentration” refers to 400 ppm Li or higher.
The systems and methods described above are configured to achieve a lithium concentration increase from about 10% to about 1,000%. In one embodiment, the lithium concentration is increased to the maximum determined by LiCl solubility limit, which is around 60,000-67,000 ppm Li in solution. In another embodiment, the lithium concentration is increased 10 to 1,000 fold, or 10 to 500 fold, or 10 to 100 fold. In another embodiment, operation of a LiTAS™ separator in a moderate recovery mode results in reduction of size of the separation equipment, thereby reducing the capital cost of separation equipment per ton of lithium processed by 30-70%, or by 40-60%. In another embodiment, operation of the LiTAS™ separator in a moderate recovery mode reduces flow through the separation equipment, thereby reducing the operating cost of separation equipment per ton of lithium processed by 20-60%, or by 30-50%. In another embodiment, the systems and methods result in high concentration brines, reducing flows through the processing plant thereby also reducing processing plant capital costs by 30-70%, or 40-60%. In another embodiment, the systems and methods result in low impurity brines, reducing reagent requirements for impurity removal through the processing plant thereby also reducing processing plant capital costs by 30-70%, or by 40-60%. In another embodiment, the systems and methods result in high concentration brines, which increase processing plant per pass recovery by 30-60% as the mother liquor concentration is fixed, or by 10-30% as the mother liquor concentration is fixed.
In one example, for brownfield operation with existing ponds, production capacity from the same ponds can be increased by 2-fold to 50-fold by treating low concentration feed brines, or by 3-fold to 20-fold with by treating medium concentration feed brines. In another example, for brownfield operation with existing ponds, production capacity from the same ponds can be increased by 4-fold to 10-fold by treating high concentration feed brines.
In one example for greenfield operation, same production can be maintained by treating low concentration feed brines with 2-50% of the pond area otherwise required to reach LiCl saturation concentration, or by treating medium concentration feed brines with 5-35% of the pond area otherwise required to reach LiCl saturation concentration. In one example, for a greenfield operation, same production can be maintained by treating high concentration feed brines with 10-25% of the pond area otherwise required to reach LiCl saturation concentration.
The systems and methods disclosed above are applicable to any salt lake, surface water, continental underground brines, geothermal brines, or other brine sources. The systems and methods are also applicable to brine concentrations of 10 ppm or higher, preferably 50 ppm or higher, and more preferably 100 ppm or higher. In one aspect of the systems and methods herein the portion of brine removed at the brine removal location is preferably 1% to 100%, 5% to 100%, 25% to 100%, or 50% to 100% of the total brine flow in the ponds. In another aspect, the increase in lithium recovery is from about 10 to about 80% (absolute units).
The Specification, which includes the Summary, Brief Description of the Drawings and the Detailed Description, and the appended Claims refer to particular features (including process or method steps) of the disclosure. Those of skill in the art understand that the invention includes all possible combinations and uses of particular features described in the Specification. Those of skill in the art understand that the disclosure is not limited to or by the description of embodiments given in the Specification.
Those of skill in the art also understand that the terminology used for describing particular embodiments does not limit the scope or breadth of the disclosure. In interpreting the Specification and appended Claims, all terms should be interpreted in the broadest possible manner consistent with the context of each term. All technical and scientific terms used in the Specification and appended Claims have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs unless defined otherwise.
As used in the Specification and appended Claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly indicates otherwise. The verb “comprises” and its conjugated forms should be interpreted as referring to elements, components or steps in a non-exclusive manner. The referenced elements, components or steps may be present, utilized or combined with other elements, components or steps not expressly referenced. The verb “operatively connecting” and its conjugated forms means to complete any type of required junction, including electrical, mechanical or fluid, to form a connection between two or more previously non-joined objects. If a first component is operatively connected to a second component, the connection can occur either directly or through a common connector. “Optionally” and its various forms means that the subsequently described event or circumstance may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.
Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that some implementations could include, while other implementations do not include, certain features, elements, and/or operations. Thus, such conditional language generally is not intended to imply that features, elements, and/or operations are in any way required for one or more implementations or that one or more implementations necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and/or operations are included or are to be performed in any particular implementation.
The systems and methods described herein, therefore, are well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While example embodiments of the system and method have been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications may readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the system and method disclosed herein and the scope of the appended claims.
This application is a Continuation-In-Part of U.S. patent application Ser. No. 17/602,808 filed Oct. 11, 2021, which is a PCT national stage entry of PCT Application No. PCT/US2021/032027 filed May 12, 2021, which claims priority from Provisional Patent Application No. 63/023,528 filed May 12, 2020, all with the same title; the entire contents of which is incorporated herein by reference.
Number | Date | Country | |
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63023528 | May 2020 | US |
Number | Date | Country | |
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Parent | 17529492 | Nov 2021 | US |
Child | 17862090 | US | |
Parent | 17602808 | Nov 2021 | US |
Child | 17529492 | US |