Patent Application
20250222406
This specification relates to membrane-based methods for processing brine comprising lithium, such as high total dissolved solids brines comprising lithium.
The following paragraphs are not an admission that anything discussed in them is prior art or part of the knowledge of persons skilled in the art.
Demand for lithium around the world has increased, and is expected to continue to increase due to its various uses across a number of industries, including its use in batteries, ceramics, chemical additives, and nuclear applications. Of these, use in the production of batteries, such as lithium-ion batteries, contributes to some of the highest consumption of lithium.
The world's lithium supply is largely found and extracted from subsurface brines that can comprise upwards of about 100 to 1,400 mg/L, or more, of lithium. Commercial processes for extracting lithium from brine may include evaporation in large ponds, followed by precipitation, leaching, or absorption processes to extract the lithium from the brine. Such processes can require months or years to complete, and may recover only a percentage of the lithium in the brine.
The following introduction is intended to introduce the reader to this specification but not to define any invention. One or more inventions may reside in a combination or sub-combination of the features described below or in other parts of this document. The inventors do not waive or disclaim their rights to any invention or inventions disclosed in this specification merely by not describing such other invention or inventions in the claims.
Demand for lithium continues to increase; for example, for battery manufacturing. However, challenges exist with processing of lithium from different sources. For example, the Salars in South America are among some of the major sources of lithium globally. Generally, isolating lithium from the Salar brines involves evaporation (for example, solar evaporation) to reduce brine volume, which triggers a precipitation of salts that removes impurities such as divalent ions. However, such processes can be time consuming, and can result in only about 40-50% of the lithium being recovered due to loss of lithium (i) via co-precipitation with divalent ions (Ca2+, Mg2+, SO42−) or with boron, and/or (ii) during further processing of the evaporated brine.
Moreover, it has been found that the incumbent evaporation and precipitation processes tend not to remove enough of the divalent ions during precipitation to reduce their concentrations to sufficiently low levels for further, membrane-based processing. For example, following evaporation and precipitation, the divalent ion concentrations in the remaining brines are often too high for nano-filtration (NF) membrane-based processes. Many incumbent nano-filtration membranes cannot operate when sulfate (SO42−) concentrations exceed about 30,000 ppm, and/or magnesium (Mg2+) concentrations exceed about 20,000 or 30,000 ppm, and/or calcium (Ca2+) concentration exceeds about 1000 or 1500 ppm. To treat brines with such high divalent ion concentrations via membrane-based processes, the osmotic pressure requirement is often >1200 Psi. However, nano-filtration membranes tend to be limited in terms of their operating pressures, based on the osmotic pressure of their feed brine streams. When the osmotic pressure of the NF feed brine stream exceeds the allowable or operational limits of the nano-filtration membrane due to divalent ion concentrations, it becomes practically impossible to use nano-filtration to remove divalent ions from feed brines. As such, further purification is often necessary, and these subsequent purification processes can result in a loss of lithium, leading to reduced recovery.
To minimize or avoid loss of lithium due to co-precipitation and/or un-treatable brines, the brines may be diluted to make them more treatable via membrane-based processes. However, the location of lithium sources can make this difficult. For example, due to drought climate conditions at salar ponds sites in Latin America, there is minimal availability of water for dilution. Some solutions considered have included direct lithium extraction (DLE) based technology, a sorption-desorption process for lithium purification. DLE generates an eluent that can be very dilute, and may need further processing like nano-filtration and/or reverse osmosis (RO) and/or thermal evaporation to concentrate it. However, RO has some of its own challenges, such as a TDS limitation (<1 lakh ppm), and higher power consumption which increases with feed TDS.
In an aspect of the present disclosure, there is provided method of processing brine comprising lithium.
In one or more examples of the present disclosure, the method comprises providing a feed brine and a draw brine to a first forward osmosis (FO) module, the feed brine and/or the draw brine comprising lithium, and forming a feed brine concentrate and a dilute draw brine. The dilute draw brine is provided to a first nanofiltration (NF) module, forming a first NF retentate and a first NF permeate comprising at least a portion of the lithium. At least a portion of the first NF retentate may be recycled to the FO module.
In one or more examples, the method further comprises providing a first brine to an initial NF module that is upstream of the first FO module, from which is formed the feed brine that is provided to the first FO module. An initial NF retentate is also formed, at least a portion of which is optionally recycled to the first FO module and/or the first NF module.
In one or more examples, the method further comprises providing the first NF permeate to a second NF module downstream of the first NF module, and forming a second NF permeate comprising at least a portion of the lithium; and forming a second NF retentate, at least a portion of which is optionally recycled upstream and/or downstream of the second NF module. The method may further comprise providing the second NF permeate to one or more subsequent NF modules downstream of the second NF module, from which are formed a subsequent NF permeate comprising at least a portion of the lithium, and a subsequent NF retentate. At least a portion of the subsequent NF retentate may be recycled upstream and/or downstream of the one or more subsequent NF modules.
In one or more examples, the method further comprises providing the feed brine concentrate as a feed solution to a second FO module downstream of the first FO module, and providing a first draw solution to the second FO module, at least a portion of the first draw solution being optionally recycled from upstream of the second FO module. From the second FO module is formed a first FO concentrate comprising at least a portion of the lithium, and a first FO diluted draw, at least a portion of which is optionally recycled to an NF module upstream and/or downstream of the second FO module. The method may further comprise providing the first FO concentrate to one or more subsequent FO modules downstream of the second FO module, and providing a second draw solution to the one or more subsequent FO modules. At least a portion of the second draw solution may be recycled from upstream of the one or more subsequent FO modules. From the one or more subsequent FO module is formed a subsequent FO concentrate comprising at least a portion of the lithium, and a subsequent FO diluted draw, at least a portion of which is optionally recycled to an NF module upstream and/or downstream of the one or more subsequent FO modules.
In one or more examples, where the method comprises providing a feed brine to the first FO module, a first brine is provided to the first NF module, forming the first NF permeate that is the feed brine provided to the first FO module, and forming the first NF retentate that is the draw brine, at least a portion of which is provided to the first FO module.
In one or more examples of the present disclosure, the draw brine comprises lithium.
In one or more examples of the present disclosure, the feed brine comprises lithium.
In one or more examples of the present disclosure, the feed brine and the draw brine comprise lithium.
In one or more examples of the present disclosure, the first brine comprises lithium.
In one or more examples, the methods as described herein may (i) allow treatment of higher total dissolved solids (TDS) brines comprising lithium, which would not otherwise be treatable by membranes-based processes due to their high solids concentrations and/or high osmotic pressures; (ii) allow for dilution of higher TDS brines comprising lithium via on-site water generation; (iii) allow concentration of brines comprising lithium that comprise higher concentrations of divalent ions, and thus have a higher osmotic pressure; (iv) allow at least partial purification of brines comprising lithium; (v) allow for replacement of energy-intensive, TDS-restricted membrane-based processes (for example, reverse osmosis processes) for concentrating lower TDS brines comprising lithium; (vi) allow processing of waste streams for recovery of lithium that would otherwise be unrecoverable; and/or (vii) a combination thereof.
In one or more examples, the methods as described herein may (i) improve overall lithium recoveries and/or yields; (ii) reduce lithium loss generally experienced when using at least some of the incumbent processes; (iii) allow lithium recovery from the brines which would otherwise be left as a waste product; and/or (iv) use brines already available on-site, such as in the Salars.
Embodiments of the present disclosure will now be described, by way of example only, with reference to the attached Figures.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
As used in the specification and claims, the singular forms “a”, “an” and “the” include plural references unless the context clearly dictates otherwise.
The term “comprising” as used herein refers to the list following being non-exhaustive, and may or may not include any other additional suitable items, for example one or more further feature(s), component(s) and/or ingredient(s) as appropriate.]
Generally, the present disclosure provides a method of processing brine comprising lithium. The method may be those discussed above or below, and may include a combination or sub-combination of the elements or method steps described above or below.
For example, a method according to the present disclosure may include providing a feed brine and a draw brine to a first forward osmosis (FO) module, the feed brine and/or the draw brine comprising lithium, and forming a feed brine concentrate and a dilute draw brine; and providing the dilute draw brine to a first nanofilitration (NF) module, and forming a first NF retentate, at least a portion of which is optionally recycled to the FO module, and forming a first NF permeate comprising at least a portion of the lithium. The method may further include providing a first brine to an initial NF module that is upstream of the first FO module, and forming the feed brine that is provided to the FO module, and forming an initial NF retentate, at least a portion of which is optionally recycled to the first FO module and/or the first NF module.
In one or more examples, one or more methods described herein may include a first brine.
The first brine may include any one or combination of the following features. The first brine may be free, or substantially free, of make-up water, make-up aqueous solutions, or any combination thereof. The first brine may not comprise make-up water, make-up aqueous solutions, or any combination thereof.
The first brine may comprise a total dissolved solids (TDS) of less than 250,000 mg/L; or a TDS between about 10,000 mg/L and about 250,000 mg/L or between about 10,000 mg/L and about 250,000 mg/L, such as between about 10,000 mg/L and about 240,000 mg/L, or between about 10,000 mg/L and about 100,000 mg/L or or between about 10,000 mg/L and about 50,000 mg/L or or between about 10,000 mg/L and about 40,000 mg/L or or between about 10,000 mg/L and about 30,000 mg/. The first brine may comprise lithium at a concentration of at least 10 mg/L, for example, lithium at a concentration of at least 500 mg/L; or lithium at a concentration between about 10 mg/L to about 6000 mg/L or between about 10 mg/L to about 2300 mg/L. The first brine may comprise divalent ions, such as Ca+2, Mg+2, SO4−; or divalent ions Ca+2, Mg+2, and/or SO4−2 at concentrations of at least 40 mg Ca+2 per L, at least 10 mg of Mg+2 per L, and/or at least 0.1 mg of SO4−2 per L. The first brine may comprise divalent ions Ca+2, Mg+2, and/or SO4−2 at concentrations of about 1000 mg/L or less or 800 mg/L or less of Ca+2; 25,000 mg/L or less or 1300 mg/L or less of Mg+2; and/or 25,000 mg/L or less or 2700 mg/L or less of SO4−2. The first brine may also comprise divalent ions Ca+2, Mg+2, and/or SO4−2 at concentrations of about 100 to about 1000 mg/L or about 100 to about 800 mg/L Ca+2; or about 10 to about 60 mg/L Mg+2, and/or about 0.1 to about 50 mg/L SO4−2.
The first brine may comprise a brine derived from an underground reservoir, such as a high total dissolved solid (salar brine), low total dissolved solids (TDS) geothermal brine; a sea water brine; a brine derived from a direct lithium eluent; or a combination thereof.
A high TDS brine may comprise a Latin American salar brine which comprise a TDS of about 100,000 to about 250,000 mg/L, and may comprise ions such as Na+, K+, Li+, Cl−, Ca+2, Mg+2, and/or SO4−2 at concentrations of about 12000 to about 15,000 mg Na+ per L, about 12000 to about 16000 mg K+ per L, about 3000 to about 6000 mg Li+ per L, about 100,000 to about 150,000 mg Cl− per L, about 50 to about 1500 mg Ca+2 per L, about 10,000 to about 25,000 mg of Mg+2 per L, and/or about 10,000 to about 25,000 mg of SO4−2 per L.
A low TDS geothermal brine may comprise a Cerro Prieto geothermal brine. The Cerro Prieto geothermal brine may comprise a TDS of about 12,000 to about 40,000 mg/L, and may comprise ions such as Na+, K+, Li+, Cl−, Ca+2, Mg+2, and/or SO4−2 at concentrations of about 4000 to about 10,000 mg Na+ per L, about 1000 to about 3000 mg K+ per L, about 10 to about 13 mg Li+ per L, about 9000 to about 27,000 mg Cl− per L, about 140 to about 800 mg Ca+2 per L, about 14 to about 60 mg of Mg+2 per L, and/or about 0.1 to about 34 mg of SO4−2 per L.
A sea water brine may comprise a TDS of less than about 40,000 to about 50,000 mg/L, and may comprise ions such as Li+, Ca+2, Mg+2, and/or SO4−2 at concentrations of <1 mg Li+ per L, about 400 mg Ca+2 per L, about 1300 mg of Mg+2 per L, and/or about 2700 mg of SO4−2 per L.
A brine derived from a direct lithium eluent comprise a TDS of about 10,000 to about 40,000 mg/L, and may comprise ions such as Li+, Ca+2, Mg+2, and/or SO4−2 at concentrations of about 100 to about 2300 mg Li+ per L, about 40 to about 150 mg Ca+2 per L, about 40 to about 150 mg of Mg+2 per L, and/or about 20 to about 200 mg of SO4−2 per L.
The first brine, as described herein, may comprise an osmotic pressure that is less than the osmotic pressure of a draw brine, as described herein.
In one or more examples, one or more methods described herein may include a feed brine.
The feed brine may free, or substantially free of make-up water, make-up aqueous solutions, or any combination thereof. The feed brine may not comprise make-up water, make-up aqueous solutions, or any combination thereof.
The feed brine may include any one or combination of the following features. The feed brine may comprise a total dissolved solids (TDS) of less than 250,000 mg/L or less than 50,000 mg/L; or a TDS between about 10,000 mg/L and about 100,000 mg/L or between about 10,000 mg/L and about 50,000 mg/L. The feed brine may comprise lithium at a concentration of at least 10 mg/L, for example, lithium at a concentration of at least 500 mg/L; or lithium at a concentration between about 10 mg/L to about 6000 mg/L or between about 10 mg/L to about 6000 mg/L. The feed brine may comprise divalent ions, such as Ca−2, Mg+2 SO4−2; or divalent ions Ca+2, Mg+2, and/or SO4−2 at concentrations of at least 5 mg Ca+2 per L, at least 3 mg of Mg+2 per L, and/or at least 1 mg of SO4−2 per L. The feed brine may comprise divalent ions Ca+2, Mg+2, and/or SO4−2 at concentrations of about 5 to about 800 mg Ca+2 per L or of about 5 to about 100 mg Ca+2 per L, about 3 to about 10,000 mg of Mg+2 per L or about 3 to about 50,000 mg of Mg+2 per L, and/or about 1 to about 15,000 mg of SO4−2 per L or about 15 to about 15,000 mg of SO4−2 per L.
In one or more examples, the feed brine may be the first brine. In such examples, the feed brine may comprise a brine derived from an underground reservoir, such as a high total dissolved solids (TDS) salar brine from Latin America or a low total dissolved solids (TDS) geothermal brine. The feed brine may comprise a sea water brine. The feed brine may comprise a brine derived from a direct lithium eluent.
In one or more examples, the feed brine comprises the NF permeate following providing the first brine to an NF module. In such examples, the feed brine may be the NF permeate of a brine derived from an underground reservoir, such as a high TDS salar brine from Latin America, a low TDS geothermal brine, a sea water brine, a brine derived from a direct lithium eluent, or a combination thereof, as provided to an NF module.
A high TDS brine may comprise a Latin American salar brine which comprise TDS of about 100,000 to about 250,000 mg/L, and may comprise ions such as Na+, K30, Li+, Cl−, Ca+2, Mg+2, and/or SO4−2 at concentrations of about 12000 to about 15,000 mg Na+ per L, about 12000 to about 16000 mg K+ per L, about 3000 to about 6000 mg Li+ per L, about 100,000 to about 150,000 mg Cl− per L, about 50 to about 1500 mg Ca+2 per L, about 10,000 to about 25,000 mg of Mg+2 per L, and/or about 10,000 to about 25,000 mg of SO4−2 per L.
A low TDS geothermal brine may comprise a Cerro Prieto geothermal brine. The Cerro Prieto geothermal brine may comprise a TDS of about 12,000 to about 40,000 mg/L, and may comprise ions such as Na+, K+, Li+, Cl−, Ca+2, Mg+2, and/or SO4−2 at concentrations of about 4000 to about 10,000 mg Na+ per L, about 1000 to about 3000 mg K+ per L, about 10 to about 13 mg Li+ per L, about 9000 to about 27,000 mg Cl− per L, about 140 to about 800 mg Ca+2 per L, about 14 to about 60 mg of Mg+2 per L, and/or about 0.1 to about 34 mg of SO4−2 per L.
A sea water brine may comprise a TDS of less than about 40,000 to about 50,000 mg/L, and may comprise ions such as Li+, Ca+2, Mg+2, and/or SO4−2 at concentrations of <1 mg Li+ per L, about 400 mg Ca+2 per L, about 1300 mg of Mg+2 per L, and/or about 2700 mg of SO4−2 per L.
A brine derived from a direct lithium eluent comprise a TDS of about 10,000 to about 40,000 mg/L, and may comprise ions such as Li+, Ca+2, Mg+2, and/or SO4−2 at concentrations of about 100 to about 2300 mg Lit per L, about 40 to about 150 mg Ca+2 per L, about 40 to about 150 mg of Mg+2 per L, and/or about 20 to about 200 mg of SO4−2 per L.
The feed brine, as described herein, may comprise an osmotic pressure that is less than the osmotic pressure of a draw brine, as described herein.
In one or more example, one or more methods described herein include a draw brine.
The draw brine may free, or substantially free of make-up water, make-up aqueous solutions, or any combination thereof. The draw brine may not comprise make-up water, make-up aqueous solutions, or any combination thereof. The draw brine may comprise a total dissolved solid concentration that precludes treatment via nanofiltration, zero liquid discharge (ZLD) processes, minimum liquid discharge (MLD) processes, or others, in the absence of dilution.
The draw brine may include any one or combination of the following features. The draw brine may include a total dissolved solids (TDS) of at least 100,000 mg/L; or a TDS between about 100,000 mg/L and about 1,000,000 mg/L, such as between about 400,000 mg/L and about 800,000 mg/L. The draw brine may comprise lithium at a concentration of at least 1 mg/L, or at least 10 mg/L, or at least 100 mg/; or lithium at a concentration between about 100 to about 10,000 mg/L, or about 6000 mg/L to about 8000 mg/L.
The draw brine may comprise divalent ions, such as Ca2+, Mg2+, SO42−; or divalent ions Ca2+, Mg2+, and/or SO42− at concentrations of at least 300 mg Ca2+ per L, at least 1000 mg of Mg2+ per L, and/or at least 500 mg of SO42+ per L. The draw brine may comprise about 1,000 mg/L or more of Ca2+, such as 1400 mg/L or more; 20,000 mg/L or more of Mg2+; and/or 65,000 mg/L or more of SO42−. The draw brine may comprise about 300 to about 2,000 mg/L of Ca2+; about 1000 to about 60,000 mg/L of Mg2+; and/or about 500 to about 65,000 mg/L or more of SO42−.
The draw brine may comprise a brine derived from an underground reservoir, such as a Salar brine; a synthetic brine; a waste-stream brine; a brine derived from an evaporation pond, such as a downstream evaporation pond; or a combination thereof.
Salar brines, such as from salars in South America, may comprise: a lithium concentration of 100 ppm or more, such as a concentration from 150 to 400 ppm or from 300 to 700 ppm; a sulfate concentration of 5,000 ppm or more; and/or, a combined magnesium and calcium concentration from 1,000 ppm or more. Waste-stream brines, such as those derived from in potash plant, may comprise a lithium concentration of up to and including 7000 ppm; and/or a sulfate concentration up to and including 65,000 ppm. Brines derived from an evaporation pond, such as a downstream evaporation pond, comprise lithium that has been enriched via series of evaporation ponds. In downstream ponds, the lithium concentration increases as it goes downstream, such that the final pond could comprises much as 6% lithium (˜70,000 ppm).
In one or more example, the draw brine may be any high TDS brine, such as a brine from concentrated Salar ponds, synthetic brines, or waste streams.
In one or more example, one or more methods described herein involve forward osmosis (FO) using a first FO module. Operating the first FO module may include any one or combination of the following features.
The first FO module may be operated at a pressure between about 15 psi and about 30 psi. The first FO module may be operated at a pressure between about 15 psi and about 30 psi, when the FO membrane has an area of about 13.8 m2.
The FO module may have an input flow rate and/or an output flow rate that corresponds to FO membrane area and/or input/output brines composition. The FO module may have an average flux across the FO membrane that is between about 5 LHM to about 25 LHM, or about 10 LHM to about 25 LHM, or about 15 to about 25 LHM, or about 20 LMH to about 25 LHM. The FO module may have an average flux across the FO membrane that is about 10 LMH to 20 LMH based on feed brine composition. The FO module may have an average flux across the FO membrane that is about 10 LMH-20 LMH, at a pressure between about 15 to about 30 psi.
The first FO module may be operated using a membrane configured to reject about 99% or more of salts. The first FO module may be operated using a hollow fiber membrane, where in the hollow fiber membrane may reject ≥99% of salts. The FO module may be operated using a membrane configured to reject about 99% or more of salts at a pressure between about 15 psi and about 30 psi. The FO module may be operated using a hollow fiber membrane at a pressure between about 15 psi and about 30 psi. The FO module may be operated at a recovery up to, or greater than 75%, where up to, or greater than 75% of water permeates across the membrane, from the feed side to the draw side, removing water from the feed brine to concentrate the feed brine; for example, by 2-5 or 4-5 times.
The first FO module may be operated using a hollow fiber semipermeable membrane comprising an active layer of polyamide thin film composite with integrated protein. The first FO module may be operated using a membrane as described in US Publication No. 20150144553, which is incorporated herein by reference.
In one or more example, one or more methods described herein involve forward osmosis (FO) using a second FO module and/or subsequent FO modules. Operating the second FO module and/or subsequent FO modules may include any one or combination of the following features.
The second FO module and/or subsequent FO modules may be operated at a pressure between about 15 psi to about 30 psi. The second FO module and/or subsequent FO modules may have an input flow rate and/or an output flow rate that corresponds to membrane area and/or input/output brines composition. The second FO module and/or subsequent FO modules may have an input flow rate and/or an output flow rate that is based on the process recovery of the first FO module. The second FO module may have an average flux across the FO membrane that is between about 5 LHM to about 25 LHM, or about 10 LHM to about 25 LHM, or about 10 to about 20 LHM, or about 10 LMH to about 15 LHM. The second FO module and/or subsequent FO modules may have an average flux across the FO membrane that is between about 10 to about 15 LMH. The second FO module and/or subsequent FO modules may have an average flux across the FO membrane that is between about 10 to about 15 LMH, at a pressure between about 15 to about 30 psi.
The second FO module and/or subsequent FO modules may be operated using a membrane configured to reject about 99% or more of salts. The second FO module and/or subsequent FO modules may be operated using a hollow fiber membrane, where in the hollow fiber membrane may reject 299% of salts. The second FO module and/or subsequent FO modules may be operated using a membrane configured to reject about 99% or more of salts at a pressure between about 15 psi and about 30 psi. The FO module may be operated using a hollow fiber membrane at a pressure between about 15 psi and about 30 psi. The FO module may be operated at a recovery up to, or greater than 50%, where up to, or greater than 50% of water permeates across the membrane, from the feed side to the draw side, removing water from the feed brine concentrate, the first FO concentrate, or subsequent FOX concentrates, to concentrate them.
The second FO module and/or subsequent FO modules may be operated using a hollow fiber semipermeable membrane comprising an active layer of polyamide thin film composite with integrated protein. The second FO module and/or subsequent FO modules may be operated using a membrane as described in US Publication No. 20150144553, which is incorporated herein by reference.
In one or more examples, one or more methods described herein involve nano-filtration (NF) using an initial NF module. Operating the initial NF module may include any one or combination of the following features.
The initial NF module may be operated at a pressure between about 80 psi to about 1600 psi, or about 130 psi to about 1600 psi or about 80 psi to about 1500 psi, or about 130 psi to about 1500 psi. The initial NF module may be operated at a pressure of about 130 psi. The initial NF module may have an input flow rate and/or an output flow rate that corresponds to membrane area and/or input/output brines composition. The initial NF module may have an average flux across the NF membrane that is between about 5 LHM to about 25 LHM, or about 10 LHM to about 25 LHM, or about 15 to about 25 LHM, or about 20 LMH to about 25 LHM. The initial NF module may have an average flux across the NF membrane that is about 10 LMH to 21 LMH based on feed composition to initial NF module. The initial NF module may have an average flux across the NF membrane that is about 10 LMH to 21 LMH, at a pressure between about 130 psi to 1600 psi.
The initial NF module may be operated at high recovery. The initial NF module may be operated at high recovery at a pressure of about 130 psi to 1600 psi. The initial NF module may be operated at high recovery at a pressure between about 80 psi and about 1500 or 1600 psi. The initial NF module may be operated at high recovery that rejects between about 80% to about 99% of Ca2+, Mg2+, and/or SO42−.
The initial NF module may be operated at a divalent % rejection that corresponds to the input brine composition, such as the divalent ion concentration of the input brine; and/or corresponds to the pressure applied across the NF membrane. The initial NF module may be operated using an NF membrane that rejects about 80% to about 85% of Ca2+, about 90% to about 95% of Mg2+, and/or about 97% to about 99% of SO42−.
In one or more examples, one or more methods described herein involve nano-filtration (NF) using a first NF module. Operating the first NF module may include any one or combination of the following features.
The first NF module may be operated at a pressure of up to 800 psi, or up to 1500 or 1600 psi; or at a pressure between about 80 psi to about 1500 or 1600 psi. The first NF module may have an input flow rate and/or an output flow rate that corresponds to membrane area and/or input/output brines composition. The first NF module may have an input flow rate and/or an output flow rate that corresponds to membrane area, diluted draw brine concentration, and/or permeate output with applied pressure. In one or more examples, the % recovery, % divalent ion rejection, and/or pressure range of the first NF module membrane may depend on input brine composition (dilute draw brine), such as ion concentrations.
The first NF module may be operated at a recovery of about 70% to about 75% (based on permeate). The first NF module may be operated at a recovery of about 70% to about 75% (based on permeate) at a pressure of about 1300 to about 1400 or 1600 Psi. The first NF module may be operated at a pressure between about 800 psi and about 1300 or 1600 psi. The first NF module may be operated at a pressure between about 80 psi and about 1500 or 1600 psi. The first NF module may be operated using an NF membrane that rejects between about 50% to about 99% of Ca2+, Mg2+, and/or SO42−. The first NF module may be operated at a divalent % rejection that corresponds to the input brine composition, such as the divalent ion concentration of the input brine; and/or corresponds to the pressure applied across the NF membrane. The first NF module may be operated using an NF membrane that rejects about 80% to about 85% of Ca2+, about 90% to about 95% of Mg2+, and/or about 97% to about 99% of SO42−. The first NF module may be operated using an NF membrane that rejects about 50% to about 60% of Ca2+, about 80% to about 85% of Mg2+, and/or about 97% to about 99% of SO42−.
In one or more examples, one or more methods described herein involve nano-filtration (NF) using a second NF module and/or subsequent NF modules. Operating the second NF module and/or subsequent NF modules may depend on the input brine composition (NF permeates), and/or the pressure applied across the NF membrane.
In one or more examples, one or more methods described herein involve nano-filtration (NF) using an initial NF module, a first NF module, a second NF module and/or subsequent NF modules. The NF membrane of any one of said NF modules may comprise a thin film composite (TFC) spiral wound NF membrane. The TFC spiral-wound NF membrane may comprise one or more of the following specifications: a membrane polymer comprising standard NF polyamide; a molecular weight cut off of about 150 to about 300 Dalton; % rejection across may be dependent on input brine composition (dilute draw brine, NF permeates) and/or applied pressure across NF membranes; a temperature tolerance of about 15° C. to about 50° C.; a pressure tolerance up about to 1500 or 1600 Psi; a solvent resistance to acidic and/or alkali solvent (such as a pH between 3 to 11); or a combination thereof. The NF membranes may be used in a pressure vessel arrangement, where a single pressure vessel may contain five to six NF membrane elements. These elements may be arranged in a number of stacks based on flow capacity.
As water 18 diffuses across the membrane 20 into the Draw Brine 14, a Dilute Draw Brine 24 is formed that has a lower osmotic pressure than the Draw Brine 14. When the Draw Brine 14 comprises lithium, diluting the Draw Brine 14 via the FO1 module 16 decreases the osmotic pressure of the Draw Brine 14, allowing the Draw Brine 14 to be processed, as desired, by other membrane-based methods that otherwise would not have been able to tolerate its osmotic pressure. This may facilitate recovery of lithium that would have otherwise been difficult to recover due to the high osmotic pressure of the brine within which it was contained.
Both the Feed Brine Concentrate 22 and Dilute Draw Brine 24 are then respectively discharged from the FO1 Module 16. The Dilute Draw Brine 24 is provided to a first nanofiltration (NF1) module 26 to filter out at least a percentage of any divalent ions that may be present in the Dilute Draw Brine 24. Divalent ions that may be present in the Dilute Draw Brine 24 include of Ca2+, Mg2+, and/or SO42−. When the Dilute Draw Brine 24 comprises such divalent ions, removing those at least partially purifies the Dilute Draw Brine 24, and further reduces its osmotic pressure, facilitating its capacity to be processed by other membrane-based methods. If the Feed Brine 12 comprises lithium, the Feed Brine Concentrate 22 may be subject to further concentration and/or purification steps, such as multi-pass forward osmosis, ion exchange (IX), evaporation, crystallization, or a combination thereof, to facilitate lithium recovery.
From the NF1 module 26, a NF1 Retentate 28 and NF1 Permeate 30 are formed and discharged. The NF1 Retentate 28 comprises at least a portion of the filtered out divalent ions from the Dilute Draw Brine 24, and the NF1 Permeate 30 comprises as least a portion of the lithium comprised by the Dilute Draw Brine 24. At least a portion of the NF1 Retentate 28 may be recycled back to the FO1 module 16, and may be mixed with the Draw Brine 14 being provided to the FO1 module 16 (dashed line), due to its higher divalent ion concentration and subsequently higher osmotic pressure. Recycling of the NF1 Retentate 28 may continue until ion saturation is reached. The NF1 Permeate 30 may be subject to further concentration and/or purification steps, such as multi-pass nano-filtration, ion exchange (IX), evaporation, crystallization, or a combination thereof, to facilitate lithium recovery. Alternatively, at least a portion of the NF1 Permeate 30 may be mixed with the Feed Brine 12 being provided to the FO1 module 16 for further concentration; or the NF1 Permeate 30 may be used as the Feed Brine 12.
As needed, the brines, concentrates, permeates, or retentates may be bled off as ion-saturation is met.
The method as depicted in
The system 10 and method as depicted in
From the NFI module 34, a NFI Retentate 36 and Feed Brine 12 (which is also NFI Permeate 38) are formed and discharged. The Feed Brine 12 and a Draw Brine 14 comprising lithium are provided to a first forward osmosis (FO1) module 16, simultaneously concentrating the Feed Brine 12, forming a Feed Brine Concentrate 22; and diluting the Draw Brine 14, forming a Dilute Draw Brine 24. If the First Brine 32 comprises lithium, the Feed Brine Concentrate 22 may be subject to further concentration and/or purification steps, such as ion exchange (IX), evaporation, crystallization, or a combination thereof, to facilitate lithium recovery. Once diluted, with a corresponding decrease in osmotic pressure, the Dilute Draw Brine 24 can be provided at least in part to (i) the NFI module 34 (not shown), or (ii) a first nanofiltration (NF1) module 26 (shown) to filter out at least a percentage of any divalent ions that may be present in the Dilute Draw Brine 24. When at least a part of the Dilute Draw Brine 24 is provided to the NFI module 34, that amount may be selected to minimize any potential impact on the downstream FO1 module 16 that may arise due to differences in osmotic pressures between the First Brine 32 and the Dilute Draw Brine 24. The NF1 module 26 may have a lower % recovery, and may operate at a higher pressure, than the NFI module 34 due to a higher concentration of ions or a higher TDS of Dilute Draw Brine 24. This may facilitate at least partially purifying the Dilute Draw Brine 24 and reducing its osmotic pressure, aiding in its capacity to be processed by other membrane-based methods, and/or facilitating lithium recovery and increasing lithium yields.
The NFI Retentate 36 comprises at least a portion of the filtered out divalent ions from the First Brine 32; and as such, at least a portion of the NFI Retentate 36 may be provided to the FO1 module 16 for further processing, optionally as a draw brine or mixed with the Draw Brine 14 being provided to the FO1 module 16 (upper dashed line), due to its higher divalent ion concentration and subsequently higher osmotic pressure. At least a portion of the NFI Retentate 36 may be provided to the NF1 module 26 for further processing, and may be optionally mixed with the Dilute Draw Brine 24 (lower dashed line).
From the NF1 module 26, a NF1 Retentate 28 and NF1 Permeate 30 are formed and discharged. The NF1 Permeate 30 may be subject to further concentration and/or purification steps, such as ion exchange (IX), evaporation, crystallization, or a combination thereof, to facilitate recovery of at least some of the lithium comprised in the Draw Brine 14. The NF1 Retentate 28 comprises at least a portion of the filtered out divalent ions from the Dilute Draw Brine 24; and as such, at least a portion of the NF1 Retentate 28 may be provided to the FO1 module 16 for further processing, and may be mixed with the Draw Brine 14 being provided to the FO1 module 16 (dashed line), due to its higher divalent ion concentration and subsequently higher osmotic pressure.
As needed, the brines, concentrates, permeates, or retentates may be bled off as ion-saturation is met.
The method as depicted in
The method as depicted in
At least a portion of the NFI Retentate 36, comprising at least a portion of the filtered out divalent ions from the First Brine 32, may be provided to the FO1 module 26 for further processing, optionally as a draw brine; mixed with the Draw Brine 14 (upper dashed line); and/or at least a portion of the NFI Retentate 36 may be provided to the NF1 module 26 for further processing, and may be optionally mixed with the Dilute Draw Brine 24 (lower dashed line).
From the NF1 module 26, a NF1 Retentate 28 and NF1 Permeate 30 are formed and discharged. The NF1 Permeate 30, comprising at least a portion of the lithium comprised in the Draw Brine 14, is provided to a second nanofiltration (NF2) module 40 that is downstream of the NF1 module 26 to filter out at least a percentage of any divalent ions remaining in the Dilute Draw Brine 24 following processing through the NF1 module 26. The NF1 module 26 may remove a majority of the divalent ions impurities in the Dilute Draw Brine 24, and impurities remaining in the NF1 permeate 30 may be removed by the NF2 module 40 to produce final permeate (NF2 Permeate 42) with a lower concentration of divalent impurities. The NF2 module 40 may have a higher % ion rejection, and may operate at equal or lower pressure than the NF1 module 26, due to a lower NF1 Permeate 30 osmotic pressure as feed to the NF2 module 40. This may facilitate at least partially purifying the NF1 Permeate 30 further, and reducing further its osmotic pressure, aiding in its capacity to be processed by other membrane-based methods, and/or facilitating lithium recovery and increasing lithium yields. The NF1 Retentate 28 comprises at least a portion of the filtered out divalent ions from the Dilute Draw Brine 24; and as such, at least a portion of the NF1 Retentate 28 may be provided to the FO1 module 16 for further processing, and may be mixed with the Draw Brine 14 being provided to the FO1 module 16 (dashed line). Alternatively, The NF1 retentate 28, or at least portions thereof, may be recycled upstream and/or downstream of the NF1 module 26 (e.g., to FO modules as a draw brine, or NF modules; not shown), or be subject to evaporation ponds, thermal ZLD processes, physiochemical treatments etc., for further lithium recovery.
From the NF2 module 40, a NF2 Retentate 44 and NF2 Permeate 42 are formed and discharged. The NF2 Permeate 42 may be subject to further concentration and/or purification steps, such as ion exchange (IX), evaporation, crystallization, or a combination thereof, to facilitate recovery of at least some of the lithium comprised in the Draw Brine 14. The NF2 Retentate 44, or at least portions thereof, may be recycled upstream 46 and/or downstream 48 of the NF2 module 40 (for example, to FO modules as part of a draw brine, or NF modules; see dashed arrows), or subject to evaporation ponds, thermal ZLD processes, physiochemical treatments etc., for further lithium recovery).
As depicted in
As needed, the brines, concentrates, permeates, or retentates may be bled off as ion-saturation is met.
The method as depicted in
The method as depicted in
From the NFI module 34, a NFI Retentate 36 and Feed Brine 12 (NFI Permeate 38) are formed and discharged. The Feed Brine 12 and a Draw Brine 14 comprising lithium are provided to a first FO module (FO1 module 16), forming a Feed Brine Concentrate 22 and a Dilute Draw Brine 24.
The Dilute Draw Brine 24 can be provided at least in part to (i) the NFI module (not shown), or (ii) a first NF module (NF1 module 26) (shown) to filter out at least a percentage of any divalent ions that may be present in the Dilute Draw Brine 24, forming an NF1 Permeate 20. When at least a part of the Dilute Draw Brine 24 is provided to the NFI module 26, that amount may be selected to minimize any potential impact on the downstream FO1 module 16 that may arise due to differences in osmotic pressures between the First Brine 32 and the Dilute Draw Brine 24. The NF1 module 26 may have a lower % ion rejection, and may operate at a higher pressure, than the NFI module 34. At least a portion of the NFI Retentate 36 may be provided to the FO1 module 16 for further processing, optionally as a draw brine; mixed with the Draw Brine 14 (upper dashed line); and/or at least a portion of the NFI Retentate 36 may be provided to the NF1 module 26 for further processing, and may be optionally mixed with the Dilute Draw Brine 24 (lower dashed line).
The Feed Brine Concentrate 22 and a First Draw Solution 56 is provided to a second FO module (FO2 module 58) to simultaneously concentrate the Feed Brine Concentrate 22 further, forming a First FO Concentrate 60; and to dilute the First Draw Solution 56, forming a First FO Diluted Draw 62. Providing the Feed Brine Concentrate 22 to the FO2 module 58 further reduces its water content and can increase lithium concentration, which can facilitate lithium recovery and increase lithium yields. The FO2 module 58 may have similar % ion rejection to the FO1 module 16, but may have a recovery that is less than FO1 module 16. The First FO Concentrate 60 may then be subject to further concentration and/or purification steps, such as ion exchange (IX), evaporation, crystallization, or a combination thereof, to facilitate recovery of at least some of the lithium comprised in the First Brine 32. The First FO Diluted Draw 62, or at least portions thereof, may be recycled upstream and/or downstream of the FO2 module 58 (for example, to the NF1 module (dashed line)). The First FO Diluted Draw 62, or at least portions thereof, may not be recycled to an NF module if the divalent ions concentration is about Ca2+≥2000 ppm, Mg2+≥30,000 ppm or ≥20,000 ppm, SO42−≥30,000 ppm. First FO Diluted Draw 62 comprising such concentrations of divalent ions may need dilution (e.g., with water, aqueous solutions) or very high pressures for NF operations; or may need to be subject to evaporation ponds, thermal ZLD processes, physiochemical treatments, etc.
The NF1 Permeate 20 discharged from the NF1 module may 26 be subject to further concentration and/or purification steps, such as ion exchange (IX), evaporation, crystallization, or a combination thereof, to facilitate recovery of at least some of the lithium comprised in the Draw Brine 14. The NF1 Retentate 28 discharged from the NF1 module 26 comprises at least a portion of the filtered out divalent ions from the Dilute Draw Brine 24; and as such, at least a portion of the NF1 Retentate 28 may be provided to the FO1 module 16 or the FO2 module 58 for further processing, optionally as a draw brine; may be mixed with the Draw Brine 14 being provided to the FO1 module 16; and/or the First Draw Solution 56 being provided to the FO2 module 58 (dashed line).
As depicted in
As needed, the brines, concentrates, permeates, or retentates may be bled off as ion-saturation is met.
The method as depicted in
The method as depicted in
A First Brine 32 comprising lithium is provided to an initial NF module (NFI module), forming a Feed Brine 12. The Feed Brine 12 is provided to a first FO module (FO1 module 16), forming a Feed Brine Concentrate 22 that is provided to a second FO module (FO2 module 58), forming a First FO Concentrate 60 that is provided to one or more subsequent FO modules (FOX module 64) to form a FOX Concentrate 66. The NFI module 34 filters out at least a percentage of any divalent ions that may be present in the First Brine 32, such as Ca2+, Mg2+, and/or SO42−, to purify the First Brine 32 and/or reduce its osmotic pressure, facilitating its capacity to be processed by other membrane-based methods (such as the subsequent FO processes depicted). The FO1 module 16, FO2 module 58 and FOX modules 64 reject >99% salt and permeate water from the feed to the draw side across the FO module. Going downstream from FO1 module 16 to FOX module 64 can result in a sequentially lower % recovery in each forward osmosis module, while sequentially reducing water content in the Feed Brine and subsequent FO Concentrates, which can increase lithium concentration and facilitate recovery of at least some of the lithium present in the First Brine.
A Draw Brine 14 comprising lithium is provided to the FO1 module 16, forming a Dilute Draw Brine 24. The Dilute Draw Brine 24 is provided to a first NF module (NF1 module 26), forming a first NF Permeate (NF1 Permeate 20) that is provided to a second NF module (NF2 module 40), forming a second NF Permeate (NF2 Permeate 42) that is provided to one or more subsequent NF modules (NFX module 50) to form a NFX Permeate 52. The NF1 module 26 may have a lower % recovery and higher operating pressure than the NFI module 34, due to a higher diluted draw brine osmotic pressure as feed to NF1 module 26. The NF2 module 40 and NFX modules 50 may have an overall higher % ion rejection, and may operate at equal or a lower pressure, than the NF1 module 26. The NF modules 26, 40, 50 sequentially filter out at least a percentage of any divalent ions that may be present, such as Ca2+, Mg2+, and/or SO42−, to purify the Dilute Draw Brine 24 and subsequent NF Permeates 20, 42, and/or reduce their osmotic pressures, facilitating their capacity to be processed by other membrane-based methods (such as the subsequent NF processes depicted), which can increase lithium concentration and facilitate recovery of at least some of the lithium present in the Draw Brine 14.
As needed, the brines, concentrates, permeates, or retentates may be bled off as ion-saturation is met.
The method as depicted in
One or more of the methods depicted in
Further, one or more of the methods depicted in
In contrast, one or more of the methods depicted in
One or more of the methods depicted in
In one or more examples, one or more methods as described herein further comprise recovering lithium. Final recovery of lithium from one or more methods as described may comprise Ion exchange (IX), thermal ZLD (Evaporation, Crystallization, etc), physiochemical treatments, or a combination thereof. In some examples, the lithium recovered is battery grade lithium.
To gain a better understanding of the invention described herein, the following examples are set forth. It should be understood that these examples are for illustrative purposes only. Therefore, they should not limit the scope of this invention in anyway.
Purification of a relatively low TDS lithium brine by removal of divalent ions was carried out using a nano-filtration module (NFI). Simultaneous concentration of the lower TDS lithium brine (permeate of NFI) and dilution of a relatively higher TDS brine was conducted using a forward osmosis module (FO1). Further purification of the diluted high TDS brine was carried out using another nanofiltration module (NF1). Products for further use included the concentrated low TDS stream from FO1 and the permeate from NF1.
Described is a method for purification and concentration of lithium from relatively low TDS or salar brines (for example, 10,000-250,000 mg/L TDS or 10,000-30,000 mg/L TDS), such as one derived from Direct Lithium Eluent (DLE) or Salar brine (150,000-250,000 mg/L); and relatively high TDS lithium brines (for example, 4-8 lakh mg/L TDS) by applying nano-filtration (NF) to remove divalent ions and forward osmosis (FO) to produce a final concentrated product with enriched lithium concentration. Simultaneously, FO dilutes the higher TDS brine (4-8 lakh mg/L TDS) to make it more readily treatable via an additional nano-filtration module. A single or multi-pass NF process together with single or multi-pass FO process may be employed.
With reference to
With reference to Tables 1-2,
The permeate from NFI, the feed brine, so treated had a resultant TDS between about 9000 to about 28000 mg/L; and was then provided as a feed stream to the first FO1 module. The draw brine comprising lithium had a TDS between about 4 to about 8 lakh mg/L, and was provided as a draw stream to the first FO1 module. With the feed and draw brines so provided to the first FO1 module, the process simultaneously concentrated the feed brine, and the lithium comprises therein, by at least about 4-5 times by removing water (for example, upwards of 90% or more of the water); and diluted the draw brine up to about 2 to about 3 lakh mg/L. The first FO1 module was operated at a pressure of <1-2 bar. Results obtained from the Forward Osmosis (FO1) process are shown in Table 1 &
So diluted, the dilute draw brine was further treatable via the downstream first NF1 module. In the second stage of the process depicted in
The combination of divalent ion removal, feed brine concentration, and/or draw brine dilution and further NF processing facilitated in a higher amount of lithium being yielded and isolated from the first brine and the draw brine. Additional lithium was also recovered from: (i) the initial NFI retentate, by combining that discharged stream with the NF1 feed; and/or (ii) from the NF1 retentate, by combining that discharged stream with the draw brine due to its relatively higher TDS. In some examples, and high osmotic pressure nature or small purge can be removed to get rid of divalent salt precipitation.
Demand for lithium continues to increase from battery manufacturers; however, many challenges exist with processing of lithium from different sources. For example, salar brine ponds are a main source of lithium in Latin America. Treating these kinds of brines for lithium recovery generally involves solar evaporation, followed by the purifications steps to make commercial grade lithium. Such processes are generally time consuming, and can result in only about 40-50% overall lithium yield due to (i) loss of lithium via co-precipitation with divalent ions (Ca2+, Mg2+, SO42−) and/or with boron, (ii) and due to higher TDS brines comprising lithium, which are generally difficult to process due to their high concentration of dissolved solids. For example, higher TDS brines having a TDS of about 4 to about 8 lakh mg/L can contain concentrations of lithium upwards or about 6000 to about 8000 mg/Lt. However, brines comprising such higher TDS cannot usually be treated by membrane-based processes.
To minimize or avoid loss of lithium due to co-precipitation or un-treatable higher TDS brines, the brines may be diluted to make them more treatable via membrane-based processes, such as to remove divalent ions. However, the location of lithium sources can make this difficult. For example, due to drought climate conditions at salar ponds sites in Latin America, there is minimal availability of water for dilution. As such, there is an impetus to find alternative solutions for fresh-water generation on site of lithium processing. Some solutions considered have included direct lithium extraction (DLE) based technology, a sorption-desorption process for lithium purification. DLE generated an eluent that can be very dilute, and may need further processing like nano-filtration and/or reverse osmosis (RO) and/or thermal evaporation to concentrate it. However, RO has some of its own challenges, such as a TDS limitation (<1 lakh ppm), and higher power consumption which increases with feed TDS.
The method described comprises an NF-FO-NF based method, as depicted in
Further, the method described comprises an NF-FO-NF based method, as depicted in
In an example of the method as described herein, the NF-FO-NF based method, as depicted in
Described herein is a method to reduce osmotic pressures of brines comprising lithium and divalent ions to the processability of make such brines via nanofiltration. In an example, the method comprises a Forward Osmosis (FO) module, to which two brines of different TDS levels were provided. One brine was a higher TDS brine comprising lithium and divalent ions (Draw Brine 14). The other brine was a lower TDS brine (Feed Brine 12). Draw Brine 14 had a very high osmotic pressure that could not be processed with conventional NF processes directly because of a high divalent ion concentration. Feed Brine 12 had a lower osmotic pressure than Draw Brine 14. During the FO process, Draw Brine 14 was used as the draw solution, Feed Brine 12 was used as the feed solution, and water flowed from Feed Brine 12 to Draw Brine 14 across a semi-permeable FO membrane 20. During the FO process, the TDS concentration (salinity, divalent ions, etc.) and thus osmotic pressure of the Draw Brine 14 gradually decreased; and the TDS concentration (salinity, divalent ions, etc.) and thus osmotic pressure of the Feed Brine 12 gradually increased. At the end of the FO process, Draw Brine 14, which initially could not be processed via nano-filtration (NF) because of its higher osmotic pressure (for example, contributed to by a higher divalent ion concentration), was converted to Dilute Draw Brine 24 and more amenable to further treatment by NF.
Described is a method of treating brines comprising lithium having a relatively high TDS (for example, a very high salinity) that is in part contributed to by a higher concentration of divalent ions. Divalent ions generally present in such brines includes Ca2+, Mg2+, and/or SO42−. Generally, nano-filtration (NF) can be used to separate these divalent ions from lithium comprised within brines. However, divalent ions can create an osmotic pressure that must be overcome during nano-filtration. If the concentration of divalent ions creates an osmotic pressure higher than the operable osmotic pressure of a nano-filtration membrane or module, brines comprising that concentration of divalent ions cannot be treated or processed by nano-filtration.
With reference to Tables 3-4,
With reference to
With reference to
With continued reference to
At least a part of the respective NF retentates 28, 44 from the multipass NF process were optionally provided to FO1 module 16 or another FO module to act as draw solutions, to reduce their TDS levels (for example, salinity), and again make the retentates amenable to the NF process. In this way, it was possible to recover further lithium from the NF retentates. Alternatively, at least a part of the retentate from the NF2 module (NF2 Retentate 44) was optionally provided back to the NF1 module 26 as part of its feed stream. Alternatively, at least a part of the retentates from both modules NF1 and NF2 (NF1 Retentate 28, NF2 retentate 44) were optionally sent to evaporation ponds 72, where the brines could be subject to further precipitation, either via solar evaporation or via chemical addition. Any brines resulting from this treatment (evaporation pond supernatant 74) comprising a lower TDS or divalent ion concentration could again be treated with nano-filtration.
With reference to
The Salars in South America are among some of the major sources of lithium globally. Generally, isolating lithium from the Salar brines comprising lithium involves a process of evaporation to reduce the volume of brine, thereby triggering a precipitation of salts to remove other impurities, such as divalent ions. Typically, the evaporation process is a lengthy process. Moreover, it has been found that the evaporation and precipitation processes tend not to remove enough of the divalent ions to reduce their concentrations to sufficiently low levels for further, membrane-based processing. For example, following evaporation and precipitation, the divalent ion concentrations in the remaining brines are often too high for nano-filtration membranes. Nano-filtration membranes tend to be limited in terms of their operating pressures, based on the osmotic pressure of their feed brine streams. When the osmotic pressure of the NF feed brine stream exceeds the allowable or operational limits of the nano-filtration membrane due to divalent ion concentrations, it becomes practically impossible to use nano-filtration to remove divalent ions from feed brines. As such, further purification has often been found to be necessary, and these subsequent purification processes have resulted in a loss of lithium, leading to reduced recovery.
Occasionally, there are waste brine streams in the Salars which have a high lithium content, but further processing is not possible because of the higher TDS levels (for example, higher divalent ion concentration and high salinity). Many incumbent nanofiltration membranes cannot operate when sulfate (SO42−) concentrations exceed about 20,000 ppm, and/or magnesium (Mg2+) concentrations exceed about 20,000 ppm, and/or calcium (Ca2+) concentration exceeds about 1,000 ppm. To treat brines with such high divalent ion concentrations via membrane-based processes, osmotic pressure requirement is often >1200 Psi. Therefore, to make these brines treatable with a lower pressure tolerate NF membrane, the divalent ion concentration must be reduced by dilution or other means. However, the Salars are often located in remote areas where there is no source of water readily available to dilute such high TDS, high salinity brines with a high divalent ion concentration. As a result, methods like ion exchange or direct extraction, which require significant clean water, are often considered not practical.
In contrast, the method described herein may (i) reduce TDS levels, salinity of brines comprising lithium that would not otherwise be treatable by nano-filtration modules and membranes (for example, Draw Brine 1) and allow use of nano-filtration for further processing of these brines; (ii) allow lithium recovery from the brines which would otherwise be left as a waste product; (iii) use brines already available in the Salars; (iv) increase TDS levels, salinity of lower TDS brines comprising lithium (for example, Feed Brine 2), thereby reducing the evaporation time required for further processing; (v) reduce lithium loss from lithium purification and extraction processes; and/or (vi) increase overall lithium yield and/or recovery.
With reference to
With reference to
With reference to
With reference to
The embodiments described herein are intended to be examples only. Alterations, modifications and variations can be effected to the particular embodiments by those of skill in the art. The scope of the claims should not be limited by the particular embodiments set forth herein, but should be construed in a manner consistent with the specification as a whole.
All publications, patents and patent applications mentioned in this Specification are indicative of the level of skill those skilled in the art to which this invention pertains and are herein incorporated by reference to the same extent as if each individual publication patent, or patent application was specifically and individually indicated to be incorporated by reference.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modification as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202211021642 | Apr 2022 | IN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2023/017593 | 4/5/2023 | WO |
