CN115916701A - Method for recovering lithium from brine - Google Patents

Abstract

A method for recovering lithium ions from a lithium-containing brine includes contacting the lithium-containing brine with a lithium ion sieve (where LIS includes an oxide of titanium or niobium) in a first stirred reactor to form a lithium ion complex containing the lithium ion sieve, and decomplexing lithium ions from the lithium ion sieve in a second stirred reactor to form the lithium ion sieve and an acidic lithium salt eluate.

Description

Method for recovering lithium from brine

Cross References to Related Applications

This application is a co-pending continuation-in-part of co-pending No. 16/410,523, filed May 13, 2019, which is a co-pending continuation-in-part of co-pending No. 16/224,463, filed December 18, 2018, which requires The benefit of U.S. Provisional Application No. 62/610,575, filed December 27, 2017, all of which are hereby expressly incorporated by reference into this application.

technical field

The present invention relates generally to methods for recovering ions from brines, and more particularly to methods for recovering lithium ions from brines.

Background technique

Demand for lithium has increased substantially and may soon outstrip supply, largely due to the recent interest in lithium-ion batteries for use in electric vehicles and stationary electricity storage associated with renewable energy systems, including wind, solar and tidal power . Lithium can be obtained in large quantities from various sources, such as seawater, brines, geothermal fluids, and continental salt lakes. As used herein, "a brine" and "brines" refer to these various lithium-containing solutions. However, to date, there are few feasible methods for recovering lithium from these sources without extensive concentration by evaporation, since the lithium concentrations in these sources are usually very low. In addition, other metal ions such as sodium, potassium, calcium, and magnesium in much higher concentrations interfere with lithium recovery.

Ion exchange is a well-known technique for recovering low concentrations of metal ions from aqueous solutions. However, conventional ion exchange resins (such as strongly acidic cation exchange resins with sulfonic acid functional groups and chelating resins with iminodiacetate groups) have high sensitivity to multivalent ions that may be present, such as calcium and magnesium. preference. While the selectivity of lithium to other monovalent ions, such as sodium and potassium, may be similar, the presence of these competing monovalent ions, which are often abundant in brines, makes lithium recovery impossible.

Inorganic ion exchange media such as ion sieves based on manganese, titanium or other oxides have been identified as potentially useful for lithium recovery from brines where high concentrations of competing ions such as calcium, magnesium, sodium and potassium are present. These materials may be referred to as Lithium Ion Sieves (LIS). Since the LIS exchange site is so narrow that Na ⁺ (0.102nm), K ⁺ (0.138nm) and Ca ²⁺ (0.100nm) with ionic radii larger than Li ⁺ (0.074nm) cannot enter the exchange site, LIS has a positive effect on lithium. higher preference. Although the ionic radius of Mg ²⁺ (0.072 nm) ions is similar to that of Li ⁺ , the dehydration of Mg ions requires a large amount of energy to bring them into the exchange sites, thereby maintaining the selectivity for Mg ²⁺ .

However, LIS has various disadvantages. First, they are slightly acidic in nature, so at lower pH levels, capacity decreases. Second, they are unstable in acidic solutions because some components are soluble in acid. As they degrade, they lose their ability to absorb lithium, so they must be replaced frequently. The cost of replacing the LIS is significant. Furthermore, disassembly and replacement of a degraded LIS (when it is installed in a conventional column) is difficult and time-consuming. Finally, LIS is synthesized as a fine powder and thus cannot be used in fixed beds like conventional ion exchange resins due to high pressure drop. Some improvements have been attempted by, for example, granulation, foaming, films, fibers and magnetization. However, when these powders are aggregated into larger geometries, the kinetics are severely compromised as binders block the pores and active exchange sites and generally reduce the surface area to volume/mass ratio at larger particle sizes.

For example, reference Chitrakar et al., "Lithium Recovery from Salt Lake Brine by H ₂ Ti0 ₃ ," Dalton Transactions, 43(23), pp. 8933-8939, June 21, 2014 (hereinafter "Chitrakar") Involves the synthesis, characterization and laboratory evaluation of metatitanic acid-based lithium-selective adsorbents. However, Chitrakar makes no mention of industrial processes and does not discuss issues regarding solid/liquid separation or washing of brine and eluent from adsorbents on an industrial scale. For example, adsorption tests in Chitrakar were performed in a beaker with an adsorbent solids concentration of 20 g/L, and elution tests were performed using HCl at an adsorbent solids concentration of 10 g/L. Chitrakar does not disclose how to use the adsorbent on a continuous industrial scale. Specifically, the laboratory filtration used in the tests would not be applicable on an industrial scale.

Therefore, there is still a need to improve the method of recovering lithium from brine using lithium ion sieves to overcome the above disadvantages.

Contents of the invention

In one aspect, the present invention provides a method for recovering lithium ions from a lithium-containing brine by contacting the lithium-containing brine with a lithium ion sieve in a first mixing or stirring reactor for less than about one hour to form a lithium-containing brine containing Lithium ion complexes of lithium ion sieves, and lithium ions are decomplexed from lithium ion sieves in a second mixing or stirring reactor to form lithium ion sieves and an acidic lithium salt eluent.

In one embodiment, a method for recovering lithium ions from a lithium-containing brine comprises contacting a lithium-containing brine with a lithium ion sieve in a first mixing or stirring reactor for less than about one hour to form a complex with the lithium ion sieve. of lithium ions. The process then includes the step of decomplexing the lithium ions from the lithium ion sieve in a second mixing or stirred reactor to form an acidic lithium salt eluent solution separated from the lithium ion sieve. Lithium ion sieves may include oxides of titanium or niobium (eg, metatitanic acid or lithium niobate).

Decomplexation can be performed by elution using an acid. The acid concentration is maintained at a constant value by adding the acid. The acid concentration should be less than 0.1M, and preferably at a pH greater than 1 and less than 3 and most preferably at a pH of about 2. The average contact time of the lithium ion complex containing the lithium ion sieve and the acid may be less than 1 hour. The acid can be hydrochloric acid or sulfuric acid.

The pH of the first reactor can be maintained at a constant value by adding base. The pH can be maintained at a constant value greater than 4 and less than 9 or greater than 6 and less than 8. The base can be sodium hydroxide (NaOH), ammonium hydroxide, potassium hydroxide, sodium carbonate, magnesium hydroxide, calcium hydroxide or anhydrous ammonia. For example, the base may be sodium hydroxide at a concentration of less than 8% w/w.

More than 90% of the lithium ion sieves may have an average particle size of less than 40 μm, and more than 90% of the lithium ion sieves may have an average particle size of greater than 0.4 μm. More than 90% by volume of the lithium ion sieve particles may be less than 100 μm in diameter and greater than 0.5 μm in diameter. More than 90% by volume of the lithium ion sieve particles may have a diameter greater than 0.5 μm. The method may further include the step of removing the lithium ion sieve having an average particle size of less than 1 μm prior to contacting the lithium-containing brine with the lithium ion sieve.

The method may further comprise separating the lithium ion complex containing the lithium ion sieve from the brine with a solid/liquid separation device; and contacting the lithium ion complex containing the lithium ion sieve with water prior to decomplexing in the second reactor A step of. The method may further comprise the steps of: separating the lithium ion sieve from the acidic lithium salt eluent solution using a solid/liquid separation device; contacting the lithium ion sieve with water after decomplexation in the second reactor to obtain regenerated lithium an ion sieve and a dilute acidic aqueous wash; and adding regenerated lithium ion sieve to the first reactor. The method may also include the step of dehydrating the lithium ion complex comprising the lithium ion sieve to a water content of less than 90% by weight prior to decomplexing the lithium ions from the lithium ion sieve in the second reactor. The method may also include the step of dehydrating the regenerated lithium ion sieve before adding to the first reactor. The step of contacting the lithium ion sieve with water may comprise contacting the lithium ion sieve with sufficient water such that greater than 50% of the lithium ions that have decomplexed from the lithium ion sieve are washed from the lithium ion sieve prior to adding regeneration Lithium ion sieve to the first reactor. The step of contacting the lithium ion sieve with water may further comprise contacting the lithium ion sieve with water in more than one countercurrent stage such that greater than 50% of the lithium ions that have decomplexed from the lithium ion sieve are removed from the lithium ion sieve Washed out, after which regenerated Li-ion sieves were added to the first reactor. The method may further include the step of adding a dilute acidic aqueous wash and additional concentrated acid to the second reactor.

The first reactor may comprise ultrafiltration membranes or microfiltration membranes. Air or other gases may be used to agitate the contents of the first reactor. At a transmembrane pressure of less than 30kPa, the flux rate through the ultrafiltration or microfiltration membrane can be greater than 30LMH.

The concentration of lithium ion sieve can be greater than 50g/L or greater than 100g/L.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are given by way of illustration only, since the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. various changes and modifications.

Description of drawings

The present invention will be more fully understood from the detailed description given below and the accompanying drawings, which are given by way of illustration only and therefore do not limit the invention. In the drawings, like reference numerals are used to refer to like features in the various views.

Figure 1 is a schematic view of an exemplary lithium extraction system for the present method.

Fig. 2 is a graph showing the amount of metal ion absorption according to pH.

Fig. 3 is a graph showing the extracted amounts of lithium and titanium according to the concentration of hydrochloric acid.

Figure 4 is a graph showing exemplary LIS particle size distributions for lithium metatitanate sieve samples taken after air agitation in the slurry for several hours.

Figure 5 is a schematic view of an alternative lithium extraction system for the present method.

Figure 6 is a graph of lithium concentration as a function of time for an exemplary extraction test.

FIG. 7 is a graph showing the extracted amounts of lithium and titanium according to pH.

Figure 8 is a graph showing the effect of contact time on lithium capacity and calcium separation.

Detailed ways

Due to the drawbacks discussed above, Li-ion sieves have not been widely used for industrial-scale Li recovery from brines so far. The present invention overcomes these disadvantages and makes the selective recovery of lithium from brines more commercially viable using lithium ion sieves.

短床离子交换工艺利用了在大规模工业应用中通常被认为是最细颗粒的物质。这些颗粒的平均粒径通常为100至200微米。Conventional ion exchange resins typically have an average particle size of about 400 to 1250 microns.

The short bed ion exchange process utilizes what would normally be considered the finest particle size for large-scale industrial applications. These particles typically have an average particle size of 100 to 200 microns.

In contrast, the lithium ion sieves used in the present invention are preferably in powder form. The average particle size of the powder is not necessarily limited. However, the average particle size is preferably less than about 100 μm, more preferably 10 to 100 μm, even more preferably 20 to 100 μm, and even more preferably 20 to 95 μm. Also, the average particle size may be 0.4 to 40 μm. For example, greater than 90% (by volume) of the lithium ion sieve particles may be less than 100 μm in diameter and may be greater than 0.5 μm in diameter. In the same or different embodiments, greater than 90% (by volume) of the lithium ion sieve particles may have a diameter greater than 0.5 μm. Since these materials are synthesized as powders, the cost of agglomeration is avoided. Furthermore, the higher surface area provided by such powders significantly improves the kinetics of the ion exchange process. In other words, Li-ion sieves are not composites held together with polymers or other binders.

Various lithium-ion sieves have potential applications in lithium recovery. Exemplary LISs include, but are not limited to, oxides of manganese and titanium. Specifically, an exemplary LIS may include an oxide of titanium, preferably metatitanic acid (MTA). However, the invention is equally applicable to other types of lithium ion sieve media, such as manganese oxides and lithium niobate (ie, niobate). Lithium ion sieves may contain dopants in addition to titanium, niobium or manganese oxides. However, the content of the Li-ion sieve will be mainly oxides of titanium, niobium or manganese.

In one embodiment of the invention, powdered lithium ion sieve media can be reacted with lithium-containing brine in a stirred tank reactor (STR or reactor). For example, the reactor can be a tank containing the liquid to be treated together with a lithium ion screen. The Li-ion sieve can be maintained in suspension by a mixer or by a fluidized bed by upward liquid or bubble flow, which provides intimate contact between the Li-ion sieve and the brine. The pH of the brine in the reactor can be maintained at a constant level by adding bases such as sodium hydroxide (NaOH), ammonium hydroxide, potassium hydroxide, sodium carbonate, magnesium hydroxide and calcium hydroxide. For example, the pH of the brine in the reactor can be maintained at greater than 5 and less than 9.

Many brines that can be treated with the present invention contain significant concentrations of magnesium. Neutralizing brines with alkali may present some problems with brines containing high concentrations of magnesium. Although magnesium hydroxide does not normally precipitate at a pH below about 8, when base is added, the localized high pH conditions at the point of contact of the base with the brine result in the precipitation of magnesium hydroxide. Despite the fact that most of the brine has a pH below the theoretical precipitation pH, the precipitate does not dissolve rapidly. The presence of magnesium hydroxide causes many problems. For example, it can adhere to the surface of LIS, thereby inhibiting lithium uptake. If the membrane is used for solid/liquid separation, it can reduce the permeate flux and possibly foul the membrane.

The problem of magnesium hydroxide precipitation is particularly severe when sodium hydroxide is utilized, and is more pronounced at higher NaOH concentrations. When using 50% w/w NaOH, a large amount of Mg(OH) ₂ was produced which did not redissolve. If a more dilute NaOH solution is used, the amount of Mg(OH) ₂ produced is less and the Mg(OH) ₂ redissolution is faster. If 4% w/w NaOH is used, only a very small amount of Mg(OH) ₂ is produced, which redissolves within seconds. Therefore, if sodium hydroxide is used, it is preferably at a concentration of less than 8% w/w.

Using dilute NaOH is disadvantageous because it dilutes the lean brine. In locations where lean brine must be re-injected into the ground, the resulting excess volume of brine can cause problems because more brine than can be pumped back into the ground cannot be pumped back.

Utilizing ammonia for neutralization avoids this problem. Ammonia can be present in the form of anhydrous ammonia gas or liquid ammonium hydroxide such that the amount of brine excess volume is negligible. Even with anhydrous ammonia or 30% ammonium hydroxide, only a small amount of Mg(OH) ₂ precipitated out at the injection point, and this precipitate redissolved quickly without negatively affecting the method.

After the ion exchange reaction is complete, the lithium-depleted (i.e., lean) brine can be separated from the lithium-ion sieve and removed from the reactor by various means. For example, the brine/Li-ion sieve slurry (i.e., the loaded Li-ion sieve) can be contacted with water in an additional stirred reactor to remove remaining brine before proceeding to the next step. Gravity settling may be used when the particle size of the lithium ion sieve is greater than about 10 microns. When the particle size is less than 10 microns, filtration devices such as drum vacuum or belt filters can be used. When the particle size is less than 1 micron, membrane filtration can be used. Combinations of these solid/liquid separation devices may be advantageously used. An example of a possible solid/liquid separation device could be a centrifuge.

After the lean brine is removed, the Li-ion sieve contained in the reactor can be contacted with the eluent. Such an eluent may especially be an acid, such as hydrochloric acid (HCl) or sulfuric acid ( _H2SO4 ). For example, the acid may be added at a concentration of about less than 0.1M, preferably at a pH greater than 1 and less than 3 and most preferably about 2. Without intending to be bound by any particular theory, it is believed that the acid elutes (decomplexes) the lithium from the LIS, thereby producing a concentrated lithium salt product solution and regenerating the LIS. As used herein, a "complex" is a combination of individual groups of atoms, ions or molecules combined to form one large ion or molecule. As used herein, "decomplexation" is the act of separating individual groups of atoms, ions or molecules from such larger ions or molecules. Since the lithium ion sieve is more selective for lithium than other metals, the ratio of lithium to other metals in the product solution can be significantly higher than in the feed brine.

After the Li-ion screen has been regenerated, the Li-ion screen can be reused to process more brine and extract more lithium.

In one embodiment of the invention, the method can be carried out continuously. In such continuous processes, two reactor stages may be required. The brine can be continuously fed to the loading stage where the lithium ion screen is contacted with the brine as a continuously mixed slurry. Li ions can then be removed from the brine via Li-ion sieve absorption, resulting in depleted brine and Li-loaded LIS. The lean brine can then be separated from the Li-loaded Li-ion sieve and removed from the reactor. The lithium-loaded Li-ion sieve, now separated from the brine, can be passed to the elution stage.

With regard to the contact time of brine with lithium ion sieves, the kinetic properties of lithium ion metatitanate sieves are known to be very poor. Lithium ions take a relatively long time to diffuse through the narrow exchange sites. Therefore, the amount of lithium absorbed by LIS is expected to increase with increasing contact time in brine. Indeed, Figure 4(b) of Chitrakar shows the effect of the contact time of LIS with saline. This data clearly shows that the amount of lithium taken up by the LIS increases over time and is a generally expected result with any ion-exchange sorbent. However, the effect of contact time on lithium uptake was found to have the opposite effect over time, as shown in Figure 8. Specifically, lithium capacity declines over time. As shown in Figure 8, the lithium capacity decreased from 15.5 mg/g at 1 hour to 12.5 mg/g at 2 hours, and further decreased to 12 mg/g after 71 hours. The Ca separation factor also decreases with contact time. More calcium and less lithium were absorbed on the LIS with increasing contact time. Perhaps given enough time, the larger calcium ions slowly diffuse into the narrow exchange sites and displace the lithium ions. This phenomenon may not be observed in Chitrakar because Chitrakar's brine has much higher lithium concentration and lower calcium concentration ([Li]=1630 mg/L, [Ca]=230 mg/L than the brine usually used in the present invention. L). In FIG. 8, the lithium concentration of the brine used in the experiment was 219 mg/L, and the calcium concentration thereof was 34,500 mg/L. Therefore, to maximize lithium capacity and calcium separation, the contact time between the LIS and the brine should be less than about 1 Hour.

An eluent may be continuously fed to the elution stage, and the lithium-loaded lithium ion sieve removed from the loading stage may be contacted with the eluent as a continuously mixed slurry. The lithium ion sieve and the liquid are separated, and this separated liquid (ie, the eluent) is the lithium salt product solution.

The Li-ion sieve leaving the elution stage has significantly lower lithium content, and the Li-ion sieve can be recycled back to the loading stage for repeated use. In this way, the lithium-ion sieve can be reused many times, and the method can be run continuously.

In one embodiment, additional stages may be used as shown in FIG. 1 . Specifically, the feed brine flows through line 2 into a first stirred reactor 4 containing lithium ion sieves as part of the loading phase. Li-ion sieves are kept in suspension by mixer 6. The brine/lithium ion sieve slurry was maintained at a constant pH by adding NaOH via line 8. The brine-laden lithium ion screen flows through line 10 into an additional stirred reactor 12 as part of the washing stage. The lean brine is separated from the loaded lithium ion screen and flows through line 14 . The lithium ion screen loaded with brine is kept in suspension by the mixer 16 . In the wash stage, the loaded lithium ion screen is contacted with water via line 18 to wash the brine from the lithium ion screen, which is believed to reduce cross-contamination of the lithium salt product by contaminating ions present in the feed brine. The washed and loaded lithium ion sieve flows through line 20 into a second stirred reactor 22 as part of the elution stage. The wash water is separated from the washed and loaded lithium ion sieve and flows through line 24 to return to the first stirred reactor 4 . The washed and loaded lithium ion sieves are kept in suspension by mixer 26 . In the elution stage, the washed and loaded lithium ion mesh is contacted with HCl via line 28 to elute lithium ions from the lithium ion mesh. The acid concentration in the second stirred reactor 22 is maintained at a constant value by adding HCl via line 28 . The regenerated lithium ion sieve flows through line 30 into an additional stirred reactor 32 as part of the pickling stage. Lithium ions are separated from the regenerated lithium ion screen as LiCl product and flow through line 34 . The regenerated lithium ion sieve is kept in suspension by mixer 36 . In the pickling stage, the remaining acid is washed from the Li-ion screen by adding water via line 38 so that the feed brine is not acidified in the load stage when the Li-ion screen is recycled and the recovered lithium is not recycled back to the load stage . The washed and regenerated Li-ion sieve flows through line 40 back to the first stirred reactor 4 to be reused in the loading phase. The dilute acid wash is separated from the washed and regenerated lithium ion screen and flows through line 44 to be used in the elution stage along with additional concentrated acid.

In one embodiment, multiple load stages can be used in series and operated in countercurrent. The brine can be initially treated in the first load stage. The treated brine from the first loading stage, which still contains some residual lithium, can be passed to the second loading stage, where contact with the lithium-ion sieve further reduces the lithium content of the brine. The Li-ion sieve from the second load stage contains some lithium but still has additional lithium capacity available that can be passed on to the first load stage. The loaded Li-ion sieve from the first loading stage is then passed to the elution stage. In this way, the lithium content of the lean brine can be further reduced. In order to further reduce the lithium content of the lean brine, an additional loading stage can be utilized in this way.

The loaded Li-ion sieve can similarly be processed in several elution stages, whereby the Li-ion sieve is passed countercurrently through the eluent stream. In this way, the lithium content of the lithium-ion sieve can be further reduced, and the lithium concentration in the eluent (ie, the lithium product) can be increased.

The exchange reaction of lithium ions absorbed from brine to lithium ion sieve is shown in formula (1):

LIS.H+Li ⁺ →LIS.Li+H ⁺ (1)

where LIS.H represents the lithium ion sieve in the form of freshly regenerated hydrogen, and

LIS.Li stands for lithium ion sieve in the form of supported lithium.

As the reaction proceeds, hydrogen ions are released into the brine, lowering the pH of the brine. For example, the active component of a lithium ion sieve can be an oxide of titanium, such as metatitanic acid (MTA). MTA is a weak acid and therefore has a high affinity for hydrogen ions. Therefore, at low pH, when hydrogen ions are available, MTA may not readily exchange hydrogen ions for lithium. Lithium ion sieves may also contain small amounts of dopants.

Figure 2 shows the uptake of metal ions according to pH. It can be seen that below a pH of about 6.5, lithium uptake is significantly reduced, while below a pH of about 4, almost no lithium is taken up. As lithium loading proceeds, the pH of the brine drops. When the pH drops to a pH of about 4, no further absorption of lithium may occur.

This phenomenon is similar to that observed with conventional polymeric weak acid cation exchange resins. The conventional way to deal with this problem is to pre-neutralize the ion exchange resin with sodium hydroxide, which converts the exchanger to the sodium form, so the pH of the solution remains constant during loading. However, this method is not suitable for Li-ion sieves because Na ions are too large to penetrate Li-ion sieves.

In one embodiment, the pH can be adjusted prior to contacting the brine with LIS by adding NaOH or another base such as sodium carbonate or ammonium hydroxide to the brine prior to treatment. Such pretreatment will raise the initial pH so that the final pH is not too low, preventing lithium uptake. However, the disadvantage of this approach is (as shown in Figure 2) that at increasing pH levels, the amount of sodium ions absorbed by the Li-ion sieve increases. Also, if the pH rises above 8, magnesium hydroxide may precipitate out of solution.

In one embodiment, the brine/lithium ion sieve slurry in the loaded reactor can be neutralized with a base, such as NaOH, in order to maintain the pH to maximize lithium uptake while minimizing sodium uptake. The pH can generally be greater than about 5 and less than about 9, preferably greater than 6 and less than 8. When the lithium ion sieve is MTA, the pH is preferably 6-7.

Li is usually eluted from the LIS with an acid (e.g., hydrochloric acid) to simultaneously regenerate the Li-ion sieve and produce a Li product, as shown in Equation (2). Lithium-ion sieves effectively neutralize the acid through this reaction.

LIS.Li+H ⁺ →LIS.H+Li ⁺ (2)

As shown in Figure 3, the amount of lithium eluted from the Li-ion sieve increased with increasing HCl concentration. For optimal elution efficiency, the acid concentration can be kept at a concentration of less than 0.1M (defined as mol dm ⁻³ , in Figure 3 ). As shown in Figure 7, the acid concentration may correspond to a pH of less than 3 and greater than 1, and preferably a pH of about 2, for optimal elution efficiency.

However, as shown in FIG. 3 , when the acid concentration is greater than 0.1M, the amount of titanium extracted from the Li-ion sieve increases, thereby deteriorating the Li-ion sieve and reducing its service life. When the acid concentration is above about 0.1M, excess titanium is extracted, resulting in an extremely short lifetime.

One way to minimize the degradation of Li-ion sieves is to minimize the contact time of the LIS with the acid. Since the lithium ion sieve is in powder form in one embodiment, the kinetics of the ion exchange process are quite fast and the exchange reaction of formula (2) above is mostly completed within one hour. In an embodiment, the contact time between the LIS and the elution acid is less than one hour. Thus, lithium is substantially completely removed from the Li-ion sieve while minimizing degradation of the Li-ion sieve.

In addition, the particle size of the lithium ion sieve particles also plays a role in the design of the systems described herein. Figure 4 shows a typical particle size distribution of a lithium metatitanate sieve sample taken after several hours of air agitation in the slurry. The effective particle size (d ₁₀ ) is about 0.5 μm, and 90% of the material (by volume) is in the range of 0.4-40 μm. Effective size is the diameter of the particles in which 10% of the total particles are smaller and 90% of the total particles are larger, on a weight or volume basis. The effective size of this material is about 0.5 μm. While the coarser material can settle from the aqueous slurry in less than an hour under the force of gravity, the finer particles are less likely to settle even after a day. Without intending to be bound by any particular theory, it is believed that the larger lithium ion sieve particles are agglomerates of fine particles produced by sintering during the synthesis process. Therefore, large particles are susceptible to mechanical abrasion during mixing with the process liquid, so the proportion of fine particles increases over time. Therefore, gravity settling is not ideal for separating lithium ion sieves from process liquids.

Membranes are increasingly used in wastewater treatment bioreactors. In a typical membrane bioreactor (MBR), microfiltration or ultrafiltration membranes with a pore size of less than 0.1 μm, whether hollow fiber, tubular or flat, are immersed in a suspension of wastewater and biosolids. Clear filtered/treated wastewater is drawn through the membrane with a vacuum. Wastewater/biosolids slurries are typically agitated by air disturbance. Air agitation facilitates oxygen transfer to the biosolids and prevents membrane fouling due to accumulation of biosolids on the membrane surface.

In membrane bioreactors, the suspended solids concentration is usually less than 30 g/L, and more typically 10-15 g/L. Higher suspension concentrations were not used because oxygen transfer was hindered due to the resulting higher and non-Newtonian fluid viscosity. In addition, higher suspended solids concentrations decrease membrane flux rates and/or increase transmembrane pressure. Typical flux rates for submerged membranes in membrane bioreactors are 10-30 liters per square meter per hour (the units are often abbreviated as "LMH").

In one embodiment, a submerged ultrafiltration or microfiltration membrane process may be used in the present invention as a means of separating the lithium ion sieve from the process liquid. The pore size of the membrane is typically less than about 1 μm, smaller than the smallest Li-ion sieve particles, so nearly 100% solids separation can be achieved. Oxygen transfer is not an issue in the present invention. However, submerged aeration (air agitation) can provide the necessary slurry mixing while the rising air bubbles scour the membrane surface to reduce membrane fouling and reduce the abrasion and shearing of LIS particles compared to mechanical mixing.

The embodiments described herein differ significantly from typical submerged membrane applications such as MBR. Li-ion sieve particles allow handling of much higher suspended solids concentrations while achieving considerably higher throughput. Fluxes obtained in conventional MBR applications are typically less than 30 LMH at transmembrane pressures of 10-30 KPa and total suspended solids (TSS) levels of less than 30 g/L. In contrast, the present invention achieves a flux as high as 300 LMH at a transmembrane pressure of 20 KPa with a Li-ion sieve at a TSS level greater than 100 g/L.

According to the present invention, the suspended solids concentration may be greater than about 50 g/L and preferably greater than 100 g/L. Without intending to be bound by any particular theory, it is believed that a higher solids concentration in the reactor is advantageous because it reduces the reactor volume required to achieve a given Li-ion sieve-liquid contact time.

In a fixed bed ion exchange system, as the acid eluent passes through the bed, its acid concentration becomes lower and is neutralized by the reaction provided by equation (2) above. To maintain the pH of the acid in contact with the Li-ion sieve less than 3 to maintain elution efficiency, the pH of the acid entering the bed can be significantly less than 1. Therefore, if the Li-ion screen is regenerated in a fixed bed, the Li-ion screen towards the inlet end of the bed will be severely degraded by the more concentrated acid.

According to the present invention, the lithium ion sieve can be regenerated as a slurry in a reactor vessel in which the lithium ion sieve is contacted with an acid of uniform concentration. The acid concentration may be maintained at a concentration of less than 0.1M, and preferably at an acid concentration corresponding to a pH of less than 3 and greater than 1, and preferably at a pH of about 2. This concentration can be maintained by continuously measuring the acid concentration of the liquid in the reactor by suitable means and adding concentrated acid as needed to maintain the concentration within the desired range (eg at pH=2).

In order to minimize impurities such as calcium, magnesium, potassium, and sodium in the final lithium salt product produced by acid elution of lithium-ion sieves, the loaded lithium-ion sieves can be mixed with water after loading and before acid elution and then Water was separated and residual feed brine was removed from the Li-ion screen. In an alternative embodiment, residual feed brine may be removed by direct filtration of the loaded lithium ion screen through a suitable filter. According to the invention, the preferred particle size of the lithium ion sieve is in the range of 0.4-40 μm. Solid particles within this range can be filtered and dehydrated using conventional solid/liquid separation devices, using filter media such as woven filter cloth with openings greater than 10 μm to replace membranes with pore sizes less than 1 μm. Therefore, most of the feed brine will be separated from the loaded Li-ion sieve. The dehydrated Li-ion sieve can then be washed directly on the filter to remove residual brine from the Li-ion sieve without reslurrying the Li-ion sieve in water. Exemplary types of filters include, but are not limited to, horizontal belt vacuum and pressure filters, drum and disc vacuum and pressure filters, pressure filter presses, and centrifuges.

As discussed above, elution of lithium from lithium ion sieves with acid produces an acidic lithium salt solution. The lithium ion sieve is preferably separated from the acidic lithium salt eluent solution to minimize the return of recovered lithium and regenerated lithium ion sieve to the loaded reactor. A similar approach can be used as it is for the separation of feed brine from supported lithium ion sieves. Therefore, the regenerated Li-ion sieve can be mixed with water, and then the water can be separated. Alternatively, the lithium ion sieve can be filtered through a suitable filter, preferably a filter with water washability.

Care should be taken to minimize the water content of the Li-ion sieve transferred to the regeneration reactor. If excess water enters the regeneration reactor with the lithium ion sieve, the recovered lithium salt eluent solution will be too dilute. Similarly, lithium should also be recovered along with the liquid entrained on the loaded Li-ion sieves taken from the regeneration reactor.

As shown in Example 1 below, the working capacity of the lithium metatitanate sieve may be about 0.01 g lithium/g lithium ion sieve. According to the dry basis, the flow rate of the lithium ion sieve is 100g lithium ion sieve/g recovered Li. It will Bring (1g lithium ion sieve/0.01g Li/100g/L lithium ion sieve) = 1.0 liter of water/g to recover lithium. Neglecting the water in the concentrated acid, the lithium concentration in the eluent is 1 g/l.

If the concentration of suspended solids in the regeneration reactor is also maintained at 100g/L and taken out at this concentration, the amount of lithium entrained by the regenerated Li-ion sieve is (1L/g Li xl g/L Li) = 1g Li/g recovered Li. In other words, all the lithium eluted from the Li-ion sieve will be taken out with the Li-ion sieve. If this Li-ion sieve is recycled directly back to the loaded reactor, no net Li will be recovered.

The regenerated Li-ion sieve slurry can be mixed with water in a scrubbing reactor to recover Li values before recycling the Li-ion sieve to the loading reactor. To separate 90% of the lithium from the Li-ion sieve, 9 liters of water are required for each gram of recovered lithium. The diluted liquid in the wash reactor can then be separated, for example by gravity or membranes. The concentration of lithium is only 0.1g/1. However, this concentration is too low for practical use. Therefore, the lithium ion sieve should be dehydrated to a water content significantly less than 90%.

For example, if the loaded Li-ion sieve slurry is dehydrated to 50% moisture (i.e. 1 liter of water/1000g of Li-ion sieve), the Li-ion sieve will only carry (1 liter of water/1000g of Li-ion sieve)/(0.01g Li/g Li ion sieve) = 0.1 liter of water/g recovered Li. Neglecting the water in the concentrated acid, the concentration of lithium in the eluent was 10 g/liter.

In addition, the regenerated Li-ion sieve should be dehydrated when it is removed from the regeneration reactor. Otherwise, a significant portion of the recovered lithium would be recycled back to the loaded reactor with the lithium-ion sieve. Even if the regenerated Li-ion sieve is highly dehydrated, loss of lithium to entrained moisture in the Li-ion sieve can be a problem. For example, if the regenerated Li-ion sieve is dehydrated to a water content of 50% by weight (i.e. 1L water/1000g Li-ion sieve), the amount of lithium entrained by the Li-ion sieve is (1L/1000g Li-ion sieve)/(0.01g Li /g lithium ion sieve) x 10g Li/IL)=1g Li/g recycles Li. In other words, all the lithium eluted from the Li-ion sieve will be taken out with the Li-ion sieve. If this Li-ion sieve is then recycled back into the loaded reactor, no net Li will be recovered.

Therefore, lithium from the liquid entrained by the dehydrated Li-ion sieve should be recovered. For example, regenerated Li-ion sieves can be washed with water. Lithium will then be recovered in the wash water. The amount of wash water should be sufficient to recover most of the lithium, but not so much that it unduly dilutes the recovered lithium brine solution. One way to do this is to reslurry the Li-ion sieve in water and then re-filter the Li-ion sieve from the slurry. To wash 90% of the lithium from the Li-ion sieve, approximately 9 mL of water is required for each mL of liquid entrained in the Li-ion sieve, such that a Li-salt solution containing 1 g/L Li is recovered under these conditions.

By utilizing two or more countercurrent washes, the amount of wash water can be reduced and the lithium concentration can be increased at the same time. Therefore, the dehydrated Li-ion sieve recovered from the first washing stage was reslurried in water again in the second washing stage and then dewatered again. The wash water recovered from the second stage dehydration unit is used in the first wash stage instead of fresh water. Using two countercurrent washing stages, the amount of water required for 90% lithium recovery can be reduced from about 9 mL of water per mL of entrained liquid to about 3 mL of water per mL of entrained liquid, and the concentration of recovered lithium can be increased from 1 g/L to about 3 g/L .

In another embodiment, the slurry can be dewatered by means such as a horizontal vacuum belt filter. The dehydrated Li-ion cake can then be washed directly on the filter. One or more countercurrent wash stages may be employed on the filter. As another option, a centrifuge can be used. If a centrifuge is used, the solids can be reslurried in water and dewatered with the centrifuge. If several wash stages are used, the dewatered solids from the first centrifuge can be reslurried with water again and then dewatered in the second centrifuge. Centrate from the second centrifuge can be used as water to slurry the solids fed to the first centrifuge. Additional centrifuges can be used in this manner to effectively achieve multi-stage countercurrent solids washing.

Such dehydration becomes more difficult if the particle size of the Li-ion sieve is too small. In fact, even though most particles are larger than 10 microns in diameter, the presence of particles much smaller than 10 microns in diameter makes dehydration difficult. In particular, if the average particle size of the ion sieve is 0.1 μm or less, dehydration is almost impossible.

In another embodiment of the present invention, the dry Li-ion sieve can be classified by a suitable device such as an air classifier, or the wet Li-ion sieve can be classified by elution to remove fine particles smaller than 1-10 microns in diameter . By doing so, separation of the lithium ion sieve from the liquid to be treated is facilitated. Removing fine particles will significantly increase the filtration rate, avoid filter media plugging, and produce a filter cake with lower water content. By removing fine particles in this way, conventional solid/liquid separation devices such as horizontal belt vacuum and pressure filters, drum and disc vacuum and pressure filters, pressure filter presses, etc. can be used more efficiently .

To maximize the purity of the recovered lithium salt product, the feed brine should be effectively separated from the loaded lithium ion sieve. For example, the purity requirements for battery-grade lithium carbonate are very stringent. Any residual feed brine retained by the loaded lithium ion screen will contaminate the product with impurities in the feed brine such as calcium, magnesium, sodium, potassium, etc. Since these impurities are present in much higher concentrations in brine than lithium, even small amounts of brine carryover can be problematic. In fact, in most cases, the impurity contribution of the brine entrained on the loaded Li-ion sieve may be greater than the amount of impurities actually exchanged to the Li-ion sieve. While additional processes such as lime/soda and ion exchange softening can be used to purify the recovered lithium solution, these additional process steps involve additional capital and operating costs. However, efficient dehydration and washing of the loaded Li-ion sieves prior to delivery to the regeneration reactor can minimize the need for these costly processes. As discussed above, as long as the Li-ion sieve does not have a significant amount of particles smaller than 1-10 microns in diameter, efficient dehydration can be achieved by conventional solid/liquid separation devices. Additionally, wash water requirements can be reduced by employing multi-stage countercurrent washing.

The present invention will hereinafter be described with reference to exemplary embodiments, which are to be understood as examples only and are not intended to limit the scope of the application.

Example

A test unit was built to illustrate the method according to one embodiment of the invention. A schematic diagram of the test unit is shown in Figure 5.

The test unit consisted of 6 reactors (R1-R6), each equipped with an air agitated diffuser and 5 of them equipped with a membrane immersion module. Reactor R4 for acid regeneration of Li-ion sieves was not equipped with membranes. Each reactor has a working volume of about 5 liters, except reactor R4, which has a working volume of about 1.1 liters.

Lithium titanate (LTO) was used as the lithium ion sieve. LTO was synthesized by reacting lithium hydroxide with titanium dioxide at a molar ratio of about 2.2:1 at a temperature of 700° C. for 4 hours. Figure 4, discussed above, provides the particle size distribution of the LTO used in this example. The initial LTO generated from the synthesis was converted to metatitanic acid (HTO) by acid washing the LTO in 0.2N HCl for 16 hours and then washing the resulting HTO with water. Reactor R1 and Reactor R2 were initially charged with 100 g/L of LIS aqueous slurry, while the remaining reactors were initially charged with 500 g/L of LIS slurry. Lithium-ion sieves were delivered as a slurry from reactor to reactor by a peristaltic pump. The flow rate of the lithium ion sieve slurry was adjusted so that the solids transfer rate was approximately 100 g/h on a dry weight basis.

The membrane modules are laboratory-scale submerged POREFLON ^TM units manufactured by Sumitomo Electric Corporation, each with an effective membrane area of 0.1 m ² . Liquid is drawn through the membrane with a vacuum using a peristaltic pump. The vacuum is maintained at less than 40kPa.

The lithium-bearing brine consisted of brine obtained from the Smackover Formation in South Arkansas, and the composition is shown in Table 1 below. After the lithium is extracted from the brine according to the method, the brine is re-fortified with lithium chloride and recycled to the process. As a result, the lithium concentration in the feed brine was slightly higher than the initial brine as received. Sodium and potassium concentrations were estimated from published brine assays.

Table 1

^* Estimated from published brine assay data.

Reactor R1 (loaded reactor) was equipped with a pH controller that automatically controlled the addition of 1N NaOH such that a pH of 7.8 was maintained. Thus, the acid generated by the ion exchange reaction is continuously neutralized. Feed brine is introduced into reactor R1 and brought into contact with HTO. HTO was fed from reactor R6 to reactor R1 as a 500 g/L slurry. The solids concentration of Li-ion sieve in reactor R1 was about 100 g/L due to mixing the concentrated slurry from reactor R6 with the feed brine. When HTO extracts lithium ions from brine, HTO is partially converted back to LTO. Lithium-depleted (ie lean) brine is pumped through the membrane.

The loaded Li-ion sieve (i.e., LTO) is withdrawn from reactor R1 as a brine slurry and directed to reactor R2, the brine wash reactor. Water is fed to reactor R2 to wash the remaining brine from the LTO. Wash water is taken from reactor R2 through another immersion module.

The loaded/washed LIS is withdrawn from reactor R2 as an aqueous slurry and directed to reactor R3, the thickener reactor. Water was withdrawn from reactor R3 through another submerged membrane module, thereby increasing the solids concentration in reactor R3 to approximately 500 g/L.

A thickened slurry of loaded/washed LIS with a solids concentration of approximately 500 g/L was withdrawn from reactor R3 and directed to reactor R4, the regeneration reactor. The lithium ion sieve in reactor R4 was contacted with hydrochloric acid at a concentration of about 0.2M. The lithium-ion sieve solids concentration in reactor R4 was about 500 g/L. Conductivity was monitored by a conductivity controller and maintained at a constant level by adding 5M HC1 to a conductivity set point of 150 mS/cm. Contacting the lithium ion sieve with acid converts it from the LTO form back to the HTO form and results in a lithium ion sieve slurry of approximately 0.2M hydrochloric acid along with lithium chloride. Reactor R4 was not equipped with membranes and only the HCl/lithium chloride lithium ion mesh slurry was overflowed to reactor R5. Recognizing that an acid concentration of 0.2M is not preferred due to excessive dissolution of titanium in the LIS, this example nonetheless illustrates the method of the invention.

Reactor R5 is the first of two pickling reactors operating in countercurrent. Most of the HCl/lithium chloride is washed from the lithium ion sieve in reactor R5, while most of the residual HCl/lithium chloride is washed from the lithium ion sieve in reactor R6. Lithium ion sieves in reactor R5 with a solids concentration of about 500 g/L were contacted with wash water from reactor R6. Acid wash water is taken from reactor R5 through another immersion membrane module. The acid wash water withdrawn from reactor R5 constitutes the lithium chloride product recovered from the process. Lithium ion sieve slurry at a concentration of about 500 g/L was withdrawn from reactor R5 and directed to reactor R6.

The fresh water added to reactor R6 washed most of the remaining HCl/lithium chloride from the lithium ion sieve. Wash water is taken from reactor R6 through another immersion membrane module and directed to reactor R5. The lithium chloride concentration in the wash water in reactor R6 is thereby reduced to less than 10% of the lithium concentration in reactor R4. The lithium ion sieve/wash water slurry is withdrawn from reactor R6 and directed back to reactor R1 where it is reused to extract lithium from the feed brine.

A continuous 12-hour test run was performed. Aliquots of lean brine and product were sampled and assayed hourly. Figure 6 shows the lean and product concentrations throughout the run. The results summarized in Table 1 are from a 1 hour composite sample taken after 10 hours of operation. The lithium concentration was reduced from 244mg/L to 61mg/L, and the recovery rate was 75%. The liquid residence time in the loaded reactor was about 1 hour.

The lithium product contains lithium at a concentration of 4,300mg/L. More lithium was removed from the product (2,322 mg/h) than was actually extracted from the brine (957 mg/h). Without intending to be bound by any particular theory, it is believed that the difference (1,365 mg/h) may be residual lithium on the Li-ion sieve that was not completely removed from the LTO during the initial pickling in HCl. Based on the actual extracted lithium from brine, the Li-ion sieve capacity is 9.6 mg/g. The liquid residence time in the strip reactor was 2.2 hours. The lithium concentration factor is about 10 times based on the loaded and recovered lithium.

The feed brine contained a calcium concentration of 22,000 mg/L, while the product contained a calcium concentration of only 1,400 mg/L. The ratio of calcium to lithium in the feed was 90. The ratio in the product was 0.33. However, only about half of the lithium in the product is actually extracted from the brine. If only lithium in the product extracted from brine is considered, the ratio of Ca to Li in the product is 0.62, which represents an enrichment factor of 90/0.62=145.

The feed brine contained an estimated sodium concentration of 43,000 mg/L, while the product contained a sodium concentration of only 9,770 mg/L. The ratio of sodium to lithium in the feed was 176. The ratio in the product was 2.3. If only lithium in the product extracted from brine is considered, the ratio of Na to Li in the product is 4.3, which represents an enrichment factor of 176/4.3=41.

The feed brine contained a magnesium concentration of 2,170 mg/L, while the product contained a magnesium concentration of only 76 mg/L. The ratio of magnesium to lithium in the feed was 8.9. The ratio in the product was 0.018. If only lithium in the product extracted from brine is considered, the ratio of Mg to Li in the product is 0.034, which represents an enrichment factor of 8.9/.034=262.

Accordingly, the systems and methods described herein have the ability to selectively recover lithium from brines containing high concentrations of calcium, sodium and magnesium.

In this example, only one brine wash reactor was used, so some brine would go to the regeneration reactor on the supported Li-ion mesh, thus carrying some calcium, sodium and/or magnesium to the regeneration on the supported Li-ion mesh reactor. Without intending to be bound by any particular theory, it is believed that by including a second brine wash reactor, the results could be improved. Furthermore, as previously discussed, the amount of Na loaded on Li-ion sieves can be reduced without significantly reducing the Li capacity by lowering the loading pH to 6–7.

comparative example

A key test was performed in Chitrakar to evaluate the effect of HCl concentration on the initial extraction of lithium and titanium from the sorbent, which is shown in Fig. 4a of Chitrakar. Figure 4a of Chitrakar shows the amount of lithium and titanium according to the concentration of HCl. The data in Chitrakar suggests that the HC1 concentration should be 0.2M or greater. In fact, Chitrakar Figure 4a does not show data for lithium extraction in sorbents below 0.1 M acid concentration, which is the preferred acid concentration for the operation of the present invention. In the present invention, the lithium and titanium components of the LTO sorbent were extracted at much lower acid concentrations than Chitrakar predicted.

References herein to terms such as "vertical," "horizontal," etc. are by way of example, not limitation, to establish a frame of reference. It should be understood that various other frames of reference may be used to describe the invention without departing from the spirit and scope of the invention. It should also be understood that features of the invention are not necessarily shown to scale in the drawings. Furthermore, to the extent that the terms "consisting of", "comprising", "having", "having", "containing" or variations thereof are used in the detailed description or claims, such terms are intended to be used in conjunction with the term " Contains/includes" similarly for inclusive and open-ended.

References herein to approximate word-modifying terms, such as "about," "approximately," and "substantially" are not to be limited to the precise value specified. Approximate terms may correspond to the precision of the instrument used to measure the value and may not indicate +/- 10% of the stated value unless otherwise relied on the precision of the instrument.

A feature that is "connected" or "coupled" to or "connected" or "coupled" to another feature may be directly connected or coupled to or directly connected or coupled to another feature, or conversely there may be one or Multiple intermediate features. A feature may be "directly connected" or "directly coupled" to or with another feature if no intervening feature exists. A feature may be "indirectly connected" or "indirectly coupled" to or with another feature if at least one intervening feature is present. A feature that is "on" or "contacting" another feature may be directly on or in direct contact with the other feature, or conversely one or more intervening features may be present. A feature may be "directly on" or "directly touching" another feature if no intervening features exist. A feature may be "indirectly on" or "indirectly contacting" another feature if at least one intervening feature is present.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should be further understood that the terms "comprising" and/or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not exclude one or more other The presence or addition of features, integers, steps, operations, elements, components and/or groups thereof.

While the invention has been illustrated by the description of various embodiments, and although these embodiments have been described in some detail, the applicants do not intend to limit or in any way limit the scope of the appended claims to such a degree of detail . Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. In order to fully enable one of ordinary skill in the art to make and use the claimed invention, applicants provide information with advantages and disadvantages of various detailed embodiments. Those of ordinary skill will appreciate that, in some applications, the disadvantages of particular embodiments as detailed above may be entirely avoided or outweighed by the overall advantages offered by the claimed invention. Accordingly, departures may be made from the above detailed teachings without departing from the spirit or scope of applicant's general inventive concept.

Claims (30)

1. A method for reclaiming lithium ions from lithium-containing brine, the method comprising: contacting the lithium-containing brine with a lithium ion sieve in a first reactor for less than about one hour to form a lithium ion complex comprising the lithium ion sieve; and decomplexing lithium ions from the lithium ion sieve in a second reactor to form an acidic lithium salt eluent solution separated from the lithium ion sieve; Wherein, the lithium ion sieve includes oxides of titanium or niobium; Wherein, the pH of the first reactor is maintained at a constant value by adding alkali. 2. The method of claim 1, wherein the decomplexation is performed by elution using an acid. 3. The method of claim 2, wherein the concentration of the acid is maintained at a constant value by adding the acid. 4. A method as claimed in claim 2 or claim 3, wherein the concentration of the acid is less than 0.1M. 5. The method of any one of claims 2 to 4, wherein the acid has a pH greater than 1 and less than 3. 6. The method of any one of claims 2 to 4, wherein the acid has a pH of about 2. 7. The method according to any one of claims 1 to 6, wherein the pH is maintained at a constant value greater than 4 and less than 9. 8. The method of any one of claims 1 to 7, wherein the pH in the first reactor is greater than 6 and less than 8. 9. The method of any one of claims 1 to 8, wherein more than 90% of the lithium ion sieves have an average particle size of less than 40 μm, and more than 90% of the lithium ion sieves have an average particle size of The diameter is greater than 0.4 μm. 10. The method of any one of claims 1 to 9, wherein more than 90% by volume of the particles of the lithium ion sieve have a diameter of less than 100 μm and a diameter of greater than 0.5 μm. 11. The method of any one of claims 1 to 9, wherein more than 90% by volume of the lithium ion sieve has particles greater than 0.5 μm in diameter. 12. The method of any one of claims 1 to 11, wherein the lithium ion sieve comprises metatitanic acid. 13. The method of any one of claims 1 to 12, further comprising: Using a solid/liquid separation device to separate the lithium ion complex containing the lithium ion sieve from brine; and The lithium ion complex containing the lithium ion sieve is contacted with water prior to decomplexing in the second reactor. 14. The method of any one of claims 1 to 13, further comprising: separating the lithium ion sieve from the acidic lithium salt eluent solution with a solid/liquid separation device; contacting the lithium-ion sieve with water after decomplexation in the second reactor to obtain a regenerated lithium-ion sieve and a dilute acidic aqueous wash; and The regenerated lithium ion sieve was added to the first reactor. 15. The method of claim 14, further comprising adding a dilute acidic aqueous wash and additional concentrated acid to the second reactor. 16. The method of any one of claims 1 to 15, wherein the average contact time of the lithium ion complex of the lithium ion-containing sieve and the acid is less than 1 hour. 17. The method of any one of claims 1 to 16, wherein the first reactor comprises an ultrafiltration membrane or a microfiltration membrane. 18. The method of any one of claims 1 to 17, wherein air is used to agitate the contents of the first reactor. 19. The method of any one of claims 1 to 18, wherein the concentration of the lithium ion sieve is greater than 50 g/L. 20. The method of claim 17, wherein the flux rate through the ultrafiltration or microfiltration membrane is greater than 30 LMH at a transmembrane pressure of less than 30 kPa. 21. The method of any one of claims 1 to 20, further comprising removing lithium ion sieves having an average particle size of less than 1 μm prior to contacting the lithium-containing brine with the lithium ion sieves. 22. The method of claim 14, further comprising decomplexing the lithium ion sieve containing lithium ion sieve prior to decomplexing the lithium ions from the lithium ion sieve in the second reactor. Dehydration to a moisture content of less than 90% by weight. 23. The method of claim 14, further comprising dehydrating the regenerated lithium ion screen prior to adding to the first reactor. 24. The method of claim 13 or claim 14, wherein contacting the lithium ion screen with water comprises contacting the lithium ion screen with water prior to adding the regenerated lithium ion screen to the first reactor. Sufficient water contact such that greater than 50% of the lithium ions that have decomplexed from the lithium ion sieve are washed from the lithium ion sieve. 25. The method of claim 24, wherein contacting the lithium ion sieve with water comprises contacting the lithium ion sieve with water at multiple The contacting is in a countercurrent stage such that greater than 50% of the lithium ions that have decomplexed from the lithium ion sieve are washed out of the lithium ion sieve. 26. The method of any one of claims 1 to 25, wherein the base comprises sodium hydroxide, ammonium hydroxide, anhydrous ammonia, potassium hydroxide, sodium carbonate, magnesium hydroxide or calcium hydroxide. 27. The method of any one of claims 2 to 6, wherein the acid comprises hydrochloric acid or sulfuric acid. 28. The method of any one of claims 1 to 27, wherein the concentration of the lithium ion sieve is greater than 100 g/L. 29. The method of any one of claims 1 to 28, wherein the base comprises anhydrous ammonia or ammonium hydroxide. 30. The method of any one of claims 1 to 29, wherein contacting the lithium-containing brine and/or the lithium ion complex with the lithium ion sieve continues for a period selected from the group consisting of Time periods: about 5 to about 59 minutes, about 15 to about 59 minutes, about 25 to about 59 minutes, about 30 to about 55 minutes, about 40 to about 55 minutes, and about 45 to about 55 minutes.

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