BACKGROUND

[0001] Due to its characteristics, such as a high electrical energy density, a high working voltage, a long cyclic life, etc., the lithium ion battery is widely used in notebook computers, mobile phones, and electric cars. The need for such batteries can be expected to grow substantially with the development of new electronic communication and transportation technologies.

[0002] Natural brines, such as those obtainable from the Smackover Formation in Arkansas, the Saltan Sea, South American formations, etc. contain lithium. Besides lithium, natural brines also contain other elements like potassium, sodium, calcium, magnesium, iron, boron, bromine, chlorine, as well as nitrates, chlorides, sulfates, and carbonates.

[0003] Known processes to isolate and recover lithium from brines, particularly high ionic strength brines, require pre-processing of the brine such as pre-concentration or removal of calcium, magnesium, iron, or other elements.

[0004] Thus, there is a need for new processes for selectively extracting lithium from brine and, in particular, such processes that require minimal or no pre-processing or other modifications as changes occur in the brine compositions to be processed.

THE INVENTION

[0005] This invention meets the above-described needs by providing sieve systems suitable for selective extraction of lithium from brines, the sieve systems comprising a plurality of manganese and/or cobalt-containing spinel structures, wherein each of a plurality of the spinel structures is affixed to a support structure. Also provided are such sieve systems wherein the support structures comprise alumina, silica, cerium oxide, or titanium oxide.

[0006] Also provided are processes that comprise combining LiOH with MnCI ₂ and/or CoCI ₂ , to form a combination, oxidizing the combination, e.g., with hydrogen peroxide, air, or elemental oxygen; washing the combination, e.g., with deionized water; drying the combination at about 300 degrees C to about 1000 degrees C, e.g., at about 400 degrees C for at least about one hour, e.g., for about two hours, to provide a crude sieve system comprising a plurality of manganese and/or cobalt-containing spinel structures; drying the crude sieve system again at about 200 degrees C to about 500 degrees C, e.g., at about 400 degrees C, for at least about 20 minutes, e.g., for about an hour, to provide a sieve system comprising a plurality of manganese and/or cobalt- containing spinel structures; combining the sieve system with an aqueous solution comprising a plurality of support structures, and optionally a binder, to form a slurry; and drying the slurry to provide a supported sieve system comprising a plurality of manganese and/or cobalt-containing spinel structures wherein each of a plurality of the spinel structures is affixed to a support structure. The sieve system can be activated with protons, e.g., by washing with a dilute acid, before or after each of a plurality of the spine! structures is affixed to a support structure. Also provided are such processes wherein at least some of the drying is done by spray drying, wherein at least some, or substantially all, of the support structures are fixed support structures, e.g., those that, comprise alumina, silica, cerium oxide or titanium oxide. Additional washing and drying steps may be used, as will be familiar to those skilled in the art.

[0007] Also provided are processes comprising combining LiC0 ₃ with MnCC>3 and/or C0CO3, to form a combination; mixing the combination; heating the crude sieve system at at least about 300 degrees C to about 1000 degrees C, e.g., at about 400 degrees C, for at least about one hour, e.g., for about 4 hours, to form a crude sieve system;

grinding the crude sieve system; heating the ground crude sieve system at 200 degrees C to about 500 degrees C, e.g., at about 400 degrees C, for at least about 20 minutes, e.g., for about an hour, to provide a sieve system comprising a plurality of manganese and/or cobalt-containing spinel structures; and causing each of a plurality of the spinel structures to be affixed to a support structure. The sieve system can be activated with protons, e.g., by washing with a dilute acid, before or after each of a plurality of the spinel structures is affixed to a support structure. Also provided are such processes wherein causing each of at least a plurality of the spinel structures to be affixed to a support structure comprises combining the sieve system with an aqueous solution comprising a plurality of support structures, and optionally a binder, to form a slurry; and drying the slurry to provide a supported sieve system comprising a plurality of manganese and/or cobalt-containing spinel structures wherein each of a plurality of the spinel structures is affixed to one of the support structures. Also provided are such processes wherein the mixing occurs in a mortar and pestle, ball mill, extruder, or v- mixer; and/or wherein grinding the crude sieve system results in a powdered crude sieve system. Also provided are such processes wherein the binder comprises flour, com starch, cellulose, or any organic that burns off above about 300 degrees C.

[0008] Also provided are processes for recovering lithium from brine, comprising passing the brine through a bed comprising a plurality of activated manganese and/or cobalt-containing spine! structures, wherein each of a plurality of the spinel structures is affixed to a support structure, such that the bed becomes at least partially loaded with lithium ions from the brine; washing the bed with dilute acid to produce an effluent comprising extracted lithium ions, and collecting the effluent comprising the extracted lithium ions. Also provided are such processes wherein the loading of lithium ions on the bed is at least about 0.1% by mass, or is 0.1-8% by mass, or is 4-5 % by mass, or is 7-8% by mass. Also provided are such processes wherein the brine is passed through the bed for a duration of about 5 seconds up to a duration of about 5 hours. Also provided are such processes where the brine is passed through the bed more than once, depending upon the pH of the brine and the duration of the pass-through. While not wishing to be bound by theory, the inventors believe that as the brine passes through the bed, some lithium ions from the brine exchange with protons inserted in or adsorbed on spinel structures; and that as the bed is washed with dilute acid, some protons from the acid exchange with lithium ions inserted in or adsorbed on the spinel structures. Also provided are such processes wherein the dilute acid comprises HCI or carbonic acid; and/or wherein the bed is a packed bed; and/or wherein the bed is fixed bed; and/or wherein the bed is a fluidized bed. Also provided are such processes further comprising, after washing the bed with dilute acid to produce an effluent comprising extracted lithium ions: passing additional brine through the bed, such that the bed again becomes at least partially loaded with lithium ions from the brine;

washing the bed again with dilute acid to produce a second effluent comprising extracted lithium ions, and collecting the second effluent comprising the extracted lithium ions.

[0009] The spinel structures of this invention can be crystalline. As used herein, the term "brine" includes any and all lithium-containing brines, including tail brines, e.g., tail brines resulting from bromine extraction or production or after H2S. As used herein, the term "dilute acid" means an acid having a concentration of less than 1 mol/ltter. As used herein, the term "supported on a support structure" means that whatever is being supported is bonded to the support structure in some manner. For example, the spinel structure can be chemically or physically bonded to a support structure. As used herein, the terms "loaded" or "loading" in regard to lithium and a bed comprising a plurality of supported spinel structures, mean that one or more lithium ions is either inserted into or adsorbed onto each of a plurality of the spinel structures. As used herein, the term "activated" in regard to a sieve system of this invention means that protons are inserted in and adsorbed onto spinel structures contained in the sieve system.

[0010] We have discovered that supported sieve systems as described herein are useful for selectively extracting lithium from brines, such as Smackover brines, without also extracting the bulk of the sodium, potassium, magnesium, calcium, etc. also present in the brines.

The Invented Sieve Systems

[0011] Sieve systems of this invention suitable for extraction of lithium from brines comprise a plurality of manganese and/or cobalt-containing spinel structures, wherein each of a plurality the spinel structures is supported on a support structure.

Processes for Preparing the Invented Sieve Systems

[0012] In accordance with this invention, a sieve system suitable for selective extraction of lithium from brines can be prepared by combining LiOH with MnC^ and/or C0CI2 to form a combination, and oxidizing the combination with hydrogen peroxide, air, or elemental oxygen, to provide a crude sieve system comprising a plurality of manganese and/or cobalt-containing spinel structures. The crude sieve system can then be washed with several portions of deionized water and dried in a conventional oven at 60 degrees C for two hours such that the crude system is comprised of a black powdery solid mixture. The crude sieve system can then be dried at 400 degrees C, e.g., in a muffle furnace, for 5 hours.

[0013] The crude sieve system can be washed with dilute acid such as HCI to place the spine!s, and thus the sieve system, in the protonated form. A third drying step (again at 60 degrees C in a conventional oven) can give the finished, unsupported H- form, spine! structure

[0001 ] Sieve systems prepared as described above can comprise a plurality of manganese and/or cobalt-containing spinel structures. Each of a plurality of the spinel structures can be affixed to support structure by techniques well established within the sieve manufacture community. For example, a sieve system of this invention can be combined with an aqueous solution comprising alumina and/or silica and the prepared slurry can be spray-dried to prepare supported spinel structures. In addition to alumina and silica, a variety of different neutral support structures can be used, including for example cerium oxide or titanium oxide. Thus, processes of this invention can provide a sieve system according to this invention comprising or consisting essentially of a plurality of manganese and/or cobalt-containing spinel structures, wherein each of a plurality of the spinel structures is supported on a support structure.

[0015] Sieve systems according to this invention can be prepared utilizing a first carbonate comprising lithium carbonate and a second carbonate comprising

manganese and/or cobalt carbonate. Substantially equimolar combinations of the first carbonate and the second carbonate can be used, also a doping metai carbonate, e.g., aluminum carbonate, iron carbonate, magnesium carbonate, cobalt carbonate, and the like, can also be included. The first carbonate and the second carbonate can be mixed in a mortar and pestle or similar equipment (e.g., ball mill, extruder, or v-mixer) and then the mixture, as is, can be heated at 400 degrees Celsius in a muffle furnace for 10 hours. The resulting crude sieve system can then be ground to a powder and piaced in a 900 degree Celsius muffle furnace for an additional 10 hours to afford the desired spinel sieve system. Treatment of same via the washing techniques described above affords a sieve system that can be used as is, or further manipulated to provide various, supported sieve systems.

[0016] Sieve systems of this invention can be supported by combining the sieve system with an aqueous solution comprising a plurality of support structures to form a slurry; and drying the slurry to provide a supported sieve system comprising a plurality of manganese and/or cobalt-containing spinel structures wherein each spinel structure is affixed to a support structure. The drying can be accomplished by spray drying.

Processes for Extracting Lithium from Brines using the invented Sieve Systems

[0017] Processes of this invention can be used for extracting lithium from brines, such as Smackover brines (e.g., from Arkansas, Louisiana, or Texas), Salton Sea brines,

South American brines, etc., including any high ionic strength brines. Processes of this invention can also be used for extracting lithium from tail brines. A supported sieve system of this invention can provide a packed bed, fixed bed, and/or fluidized bed supported sieve system that has good flow characteristics with modest pressure drops, which can be utilized in selective lithium extraction from various brines. Such a packed bed, fixed bed, and/or f!uidized bed supported sieve system can be placed in a down- flow column (although up-flow conditions can also be utilized if desirable) and brine can be eluted through the bed to charge the supported sieve system with lithium ions. The extracted lithium ions can be recovered by washing the contents of the column with dilute acid such as HCI or carbonic acid, and collecting the effluent comprising the extracted lithium ions. The packed bed, fixed bed, and/or fluidized bed supported sieve system can then be re-used with another portion of brine or tail brine to extract lithium as before. This extraction and recovery operation can be repeated as desired without additional treatment to the packed bed, fixed bed, and/or fluidized bed supported sieve system.

Example

[0018] A tailbrine comprising about 30,000 ppm Ca, about 60,000 ppm Na, about 3,000 ppm Mg, and about 100-300 ppm Li is passed through a bed comprising an activated sieve system of this invention such that the composition of the tailbrine after passing through the bed is unchanged except that the tailbrine now contains about 50- 100 ppm Li.

[0019] Supported sieve systems of this invention allow for acceptably low pressure drops when operated in a packed bed column for extraction of Li from brines, tail brines, and other brine complexes. Alternatively, the supported spinel structure systems can be utilized in a fluidized bed system for extraction of Li from brines, tail brines, and other brine complexes.

[0020] This invention is advantageous in that a manganese or cobalt -spinel sieve prepared in accordance with this invention can be used for selectively extracting lithium from Smackover brines in a commercially useful manner, for example, in continuous, packed columns, for lithium extraction and recovery on commercially applicable scale. The inventors have discovered that sieve systems of this invention are more accessible and have higher surface area as compared to other systems; that the supports protect the spinels from damage; and that the sieve systems dramatically reduces the pressure drop as compared to other systems.

[0021] In addition, although this invention has many of the features found in "ion- exchange" resins, this system is entirely inorganic in nature and does not have the weaknesses afforded by typical organic-backbone resins generally utilized. This sieve system has the strong advantage of not requiring a pre-treatment to remove other salts before isolating the desirable and valuable lithium component.

[0022] The system described has the advantage of being able to perform selective lithium extraction from brine streams. Other ions typically present in brines, e.g., Na, Mg, and Ca, will not fit within the sieve structure and are, therefore, rejected during operation of the sieve system in a packed bed, fixed bed, and/or fluidized bed system. In processes according to this invention, the selectivity of lithium vs. sodium can be as high as 30,000 to 1 (presumably even selective enough to harvest lithium from sea water if one was so inclined). This provides the ability to extract lithium from high ionic strength brines without extensive and expensive pre-processing. The commercial value of this invention, therefore, is significant.

[0023] It is to be understood that the reactants and components referred to by chemical name or formula anywhere in the specification or claims hereof, whether referred to in the singular or plural, are identified as they exist prior to being combined with or coming into contact with another substance referred to by chemical name or chemical type (e.g., another reactant, a solvent, or etc.). It matters not what chemical changes, transformations and/or reactions, if any, take place in the resulting

combination or solution or reaction medium as such changes, transformations and/or reactions are the natural result of bringing the specified reactants and/or components together under the conditions called for pursuant to this disclosure. Thus the reactants and components are identified as ingredients to be brought together in connection with performing a desired chemical reaction or in forming a combination to be used in conducting a desired reaction. Accordingly, even though the claims hereinafter may refer to substances, components and/or ingredients in the present tense ("comprises",

"is", etc.), the reference is to the substance, component or ingredient as it existed at the time just before it was first contacted, combined, blended or mixed with one or more other substances, components and/or ingredients in accordance with the present disclosure. Whatever transformations, if any, which occur in situ as a reaction is conducted is what the claim is intended to cover. Thus the fact that a substance, component or ingredient may have lost its original identity through a chemical reaction or transformation during the course of contacting, combining, blending or mixing operations, if conducted in accordance with this disclosure and with the application of common sense and the ordinary skill of a chemist, is thus wholly immaterial for an accurate understanding and appreciation of the true meaning and substance of this disclosure and the claims thereof. As will be familiar to those skilled in the art, the terms "combined", "combining", and the like as used herein mean that the components that are "combined" or that one is "combining" are put into a container with each other. Likewise a "combination" of components means the components having been put together in a container,

[0024] While the present invention has been described in terms of one or more preferred embodiments, it is to be understood that other modifications may be made without departing from the scope of the invention, which is set forth in the claims below.