Lithium extraction process

Abstract

Disclosed herein are methods of recovering lithium from lithium-containing materials. More specifically, the methods disclosed herein include heating a lithium-containing material with a solid roasting agent; forming an aqueous suspension to allow at least a portion of the lithium to be leached into the water; separating a liquid phase from a solid phase; and then exposing the collected solid phase to an acid to allow acid leaching of the remaining amount of lithium.

Description

[0001] This application is a divisional application of the patent application for invention with the application date of February 19, 2021, application number 202180016054.5, and invention title "Lithium extraction process".

[0002] Cross-reference to related applications

[0003] This application claims the benefit of U.S. Provisional Application No. 62 / 978,992, filed on February 20, 2020, the entire content of which is incorporated herein by reference. Technical field

[0004] The present invention relates to the technical field of lithium extraction, and particularly to a lithium extraction process for extracting lithium from mineral sources. Background art

[0005] Lithium is one of the key elements with wide applications in next-generation technologies, including energy storage, electric mobility, and cordless devices (Meshram, P., Pandey, B. D., & Mankhand, T. R. (2014). “Extraction of lithium from primary and secondary sources by pre-treatment, leaching and separation: A comprehensive review. Hydrometallurgy,” 150, 192 - 208.; Martin, G., Rentsch, L., Hoeck, M., & Bertau, M. (2017). “Lithium market research - global supply, future demand and price development.” Energy Storage Materials, 6, 171 - 179.). Due to its unique applications, lithium cannot be substituted in most applications; thus, the annual demand is expected to grow steadily by 8% to 11% (Baylis, R., 2013, January. “Evaluating and forecasting the lithium market from a value perspective.” In Roskill presentation, 5th Lithium Supply and Markets Conference, Las Vegas (pp. 29 - 31); ENTR, E. (2014). “Report on Critical Raw Materials for the EU. Ares” (2015), 1819503). To meet the growing demand for lithium, all viable resources need to be explored and processed.

[0006] The two main sources of lithium are ores (e.g., spodumene minerals) and brine sources. Li-rich clay sources are regarded as secondary sources. Additional Li sources can include discarded Li batteries and other recycled products.

[0007] As Figure 1As shown in the general flow chart, lithium is extracted from ores / minerals through mineral processing, followed by roasting and then leaching, while the process of extracting lithium from brines includes evaporation, precipitation, adsorption, and ion exchange (Garrett, D. E. (2004). Handbook of lithium and natural calcium chloride. Elsevier).

[0008] Spodumene minerals are the main source of high-purity lithium that can exist in the α-phase, β-phase, and γ-phase (Salakjani, N. K., Singh, P., and Nikoloski, A. N. (2016). Mineralogical transformations of spodumene concentrate from Greenbushes, Western Australia. Part 1: Conventional heating. Minerals Engineering, 98, 71 - 79) and contain a chemical composition of approximately 8 wt.% of Li 2 O, 27.4 wt.% Al 2 O 3 , and 64.6 wt.% SiO 2 ; Brumbaugh, R. J., and Fanus, W. E. (1954). Determination of lithium in spodumene by flame photometry. Analytical Chemistry, 26(3), 463 - 465). The α-spodumene phase, which belongs to the pyroxene group, is a naturally occurring crystal structure. β-spodumene is a recrystallization product that forms when α-spodumene is heated at temperatures above 800 to approximately 1100 °C. The β-spodumene phase has an interlocking (Si, Al)O 4Five-membered ring. The γ-spodumene phase is a metastable phase that appears when α-spodumene is heated at 700-900°C (Kotsupalo, NP, Menzheres, LT, Ryabtsev, AD, and Boldyrev, VV (2010). "Mechanical activation of α-spodumene for further processing into lithium compounds." Theoretical Foundations of Chemical Engineering, 44 (4), 503-507).

[0009] Current technology does not allow leaching of lithium from the α-spodumene phase, so most methods for extracting lithium from spodumene focus on modifying the crystal structure of concentrated spodumene minerals into leachable β-spodumene using conventional heating (roasting) at 950-1100° C. After the phase transformation to β, the spodumene is further mixed with sulfuric acid and heated at a temperature range of about 200-300° C. As a result, the hydrogen ions in the sulfuric acid replace the lithium in the β-spodumene, and thus, the lithium ions combine with sulfate ions to form lithium sulfate that is soluble in aqueous solution (U.S. Patent 2,516,109).

[0010] However, such high temperature roasting processes (especially the roasting of α-spodumene to β-spodumene) are very energy intensive and have been a bottleneck for the economic extraction of lithium from ores. There has been a lot of research on the extraction of lithium from β-spodumene, but there is limited literature on Li recovery from α-spodumene. Therefore, the main purpose of this study is to develop an economically viable process for extracting lithium directly from α-spodumene.

[0011] Therefore, there is a need for more energy-efficient and environmentally friendly methods to extract lithium at high yields. The present disclosure at least partially satisfies these needs and other needs. Summary of the invention

[0012] The present invention relates to a method for extracting lithium from a mineral source. The disclosed method is more energy efficient and does not require heating to very high temperatures.

[0013] In one aspect disclosed herein, a method includes: a) heating a mixture of a lithium-containing material provided in the form of a water-insoluble solid and a solid roasting agent for a first predetermined time to form a solid composition comprising at least one water-soluble phase and at least one water-insoluble phase, wherein the at least one water-soluble phase comprises a first amount of lithium and wherein the at least one water-insoluble phase comprises a second amount of lithium; wherein the heating is carried out at a heating temperature of from about 100 °C to less than about 850 °C; b) suspending the solid composition in a first water aliquot for a second predetermined time, thereby dissolving the at least one water-soluble phase and forming a first suspension comprising a first solid phase and a first liquid phase, wherein the first liquid phase comprises a first portion of the first amount of lithium and wherein the first solid phase comprises the at least one water-insoluble phase containing the second amount of lithium; c) recovering the first portion of the first amount of lithium from the first liquid phase; and d) optionally: i) suspending the first solid phase in a second water aliquot for a third predetermined time to form a further suspension comprising a further solid phase and a further liquid phase; ii) recovering a further portion of the first amount of lithium from the further liquid phase; and iii) subjecting the further solid phase to steps i)-ii) if the further liquid phase is not substantially free of the further portion of the first amount of lithium in the further liquid phase.

[0014] In other aspects, the roasting agent comprises one or more compounds containing one or more of alkali metals, alkaline earth metals or ammonium-based compounds or combinations thereof. In yet further aspects, the lithium-containing material comprises α-spodumene, lepidolite, hectorite, jadarite, Li-rich clay, Li batteries, coal and coal by-products, and mining and processing waste streams of minerals and oil shales, coal bottom clay, coal overburden, recycled materials, or any combination thereof.

[0015] In yet further aspects, the method disclosed herein further includes: a) adding a first aliquot of an acid to the first solid phase or the further solid phase when present; b) suspending the first solid phase or the further solid phase when present in the amount of acid for a fourth predetermined time to form an additional suspension comprising an additional solid phase and an additional liquid phase, wherein the additional liquid phase comprises a first portion of the second amount of lithium and wherein the additional solid phase comprises a second portion of the second amount of lithium.

[0016] Also disclosed are aspects where the method further comprises the following sequence of steps: i) adding a second aliquot of the acid to the additional solid phase to form a further additional suspension comprising a further additional solid phase and a further additional liquid phase, wherein the further additional liquid phase optionally comprises a further portion of the second amount of lithium; ii) separating the further additional liquid phase and the further additional solid phase; if the further additional liquid phase comprises the further portion of the second amount of lithium, subjecting the further additional solid phase to steps i)-ii) further; if the further additional liquid phase is substantially free of the further portion of the second amount of lithium, recycling the further additional liquid phase to the first aliquot or the second aliquot of the acid.

[0017] Additional aspects of the disclosure will be set forth in part in the detailed description, the drawings, and the appended claims, and will in part be derived from the detailed description, or can be learned by practice of the invention. It is to be understood that both the foregoing summary and the following detailed description are exemplary and explanatory only and do not limit the invention disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A general flow chart of lithium extraction is depicted.

[0019] Figure 2 A schematic diagram depicting exemplary process steps in one aspect is shown.

[0020] Figure 3 A schematic diagram depicting exemplary process steps involving a spodumene concentrate sample in one aspect is shown.

[0021] Figure 4 The lithium recovery rates when using various roasting agents are depicted.

[0022] Figure 5 The elemental recovery rates during the water leaching and acid leaching steps performed after roasting α-spodumene in the presence of NaOH at 320 °C are depicted. Error bars indicate standard error.

[0023] Figure 6 A temperature-time graph of an exemplary microwave heating of a pure spodumene sample in the absence of a roasting agent is depicted.

[0024] Figure 7 The recovery rates of various elements are depicted when α-spodumene is microwave heated (1.5 kW) in the presence of NaOH at 400 °C, the roasted product is water leached, and then acid leached.

[0025] Figure 8Describes the recovery rates of various elements when a coal overburden layer (clay-rich shale) is heated by microwave (1.5 kW) in the presence of NaOH at 400 °C, the calcined product is subjected to water leaching, and then acid leaching, and compares the results with the acid leaching of the untreated sample. Detailed implementation

[0026] The present invention can be more easily understood by referring to the following detailed description, examples, drawings, and claims, as well as the descriptions before and after them. However, before disclosing and describing the articles, systems, and / or methods of the present invention, it should be understood that unless otherwise stated, the present invention is not limited to the specific or exemplary aspects of the disclosed articles, systems, and / or methods, as these aspects can of course vary. It should also be understood that the terms used herein are only for describing specific aspects and are not intended to be limiting.

[0027] The following description of the present invention is provided as an effective teaching of the best, currently known aspects of the present invention. To this end, those skilled in the relevant art will recognize and understand that many changes can be made to the various aspects of the present invention described herein, while still obtaining the beneficial results of the present invention. It is obvious that some desired benefits of the present invention can be obtained by selecting some features of the present invention without using other features. Therefore, those of ordinary skill in the relevant art will recognize that many modifications and adaptations of the present invention are possible and, in some cases, even desirable, and are part of the present invention. Therefore, the following description is provided again as an illustration of the principles of the present invention, rather than a limitation thereof.

[0028] Definitions

[0029] As used herein, the singular forms "a", "an", and "the" include plural referents unless the context clearly indicates otherwise. Thus, for example, reference to "a water aliquot" includes aspects having two or more water aliquots unless the context clearly indicates otherwise.

[0030] In this document, ranges can be expressed as from "about" one specific value, and / or to "about" another specific value. When expressing such a range, another aspect includes from one specific value and / or to another specific value. Similarly, when a value is expressed as an approximation, by using the antecedent "about", it will be understood that the specific value forms another aspect. It should be further understood that each endpoint of the ranges in the range is both significantly related to and independent of the other endpoint.

[0031] Similarly, when values are expressed as approximations, by use of the antecedent "about", the specific value is understood to form one aspect. It should be further understood that each endpoint of each range in the ranges is significant with respect to, and independent of, the other endpoint. Unless otherwise stated, the term "about" means within 5% of the specific value modified by the term "about" (e.g., within 2% or 1%).

[0032] Throughout this disclosure, various aspects of the invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Thus, the description of a range should be considered to have specifically disclosed all the possible sub-ranges and individual numerical values within that range. For example, the description of a range such as 1 to 6 should be considered to have specifically disclosed sub-ranges such as 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, etc., and the individual numbers within that range (e.g., 1, 2, 2.7, 3, 4, 5, 5.3, 6) and any whole and fractional increments therebetween. This applies regardless of the breadth of the range.

[0033] As used herein, the term "optional" or "optionally" means that the subsequent described event or circumstance may or may not occur, and the description includes both the case where the event or circumstance occurs and the case where the event or circumstance does not occur.

[0034] The weight parts of a particular element or component in a composition or article referred to in the specification and the appended claims represent the weight relationship between the element or component and any other element or component in the composition or article, where the weight parts are expressed for the composition. Thus, in a composition or a selected portion of a composition containing 2 weight parts of component X and 5 weight parts of component Y, X and Y are present in a weight ratio of 2:5 and always in this ratio, regardless of whether additional components are included in the composition.

[0035] The weight percentage of a component, unless specifically stated to the contrary, is based on the total weight of the formulation or composition, where the component is included in the formulation or composition.

[0036] It should be understood that if the molar mass of a particular compound or composition is known, the weight percentage can be converted to a molar percentage. In a further aspect, if the volume of a particular compound or composition is known, the molar percentage can be converted to a volume percentage.

[0037] It should also be understood that the terms used herein are for the purpose of describing particular aspects only and are not intended to be limiting. As used in the specification and claims, the term "comprising" can include aspects of "consisting of" and "consisting essentially of". In addition, in some aspects, the terms "include", "including", and / or "incorporating" may be used. In such aspects, these terms are intended to be construed broadly without any limitation.

[0038] For the terms "for example" and "such as" and their grammatical equivalents, unless otherwise expressly stated, it should be understood that the term is immediately followed by the phrase "and without limitation".

[0039] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It should be understood that in some aspects, the term "and / or" includes any one of the associated listed items, while in other aspects, it may include all or any combination of the associated listed items.

[0040] It should be understood that although the terms "first", "second", "further", "additional", etc. may be used herein to describe various elements, mixtures, compositions, components, regions, layers, and / or sections. These elements, mixtures, compositions, components, regions, layers, and / or sections should not be limited by these terms. These terms are only used to distinguish one element, mixture, composition, component, region, layer, or section from another element, mixture, composition, component, region, layer, or section. Thus, the first element, mixture, composition, component, region, layer, or section discussed below may be referred to as the second element, mixture, composition, component, region, layer, or section without departing from the teachings of the exemplary aspects.

[0041] As used herein, the term "substantially", when used in reference to a composition, means at least about 80 wt%, at least about 85 wt%, at least about 90 wt%, at least about 91 wt%, at least about 92 wt%, at least about 93 wt%, at least about 94 wt%, at least about 95 wt%, at least about 96 wt%, at least about 97 wt%, at least about 98 wt%, at least about 99%, or about 100 wt% of the specified feature or component based on the total weight of the composition.

[0042] As used herein, the term "substantially" in contexts such as "substantially free of" means that the composition has less than about 1 wt%, such as less than about 0.5 wt%, less than about 0.1 wt%, less than about 0.05 wt%, or less than about 0.01 wt% of the stated material based on the total weight of the composition.

[0043] As used herein, the term "substantially" in contexts such as "substantially the same" or "substantially similar" means that a method, composition, article, or component is at least about 80%, at least about 85%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99%, or about 100% similar to a method, composition, article, or component with which it is being compared.

[0044] As used herein, the term or phrase "effective", "effective amount", or "effective conditions" means such an amount or conditions that are capable of performing the function or property expressed by the effective amount or effective conditions. As will be pointed out below, the exact amount or specific conditions required will vary depending on different aspects, which depend on recognized variables such as the materials used and the processing conditions observed. Therefore, it is not always possible to specify an exact "effective amount" or "effective conditions". However, it should be understood that an appropriate effective amount will be readily determined by a person of ordinary skill in the art using only routine experimentation.

[0045] As used herein, the term "substantially the same reference composition" or "substantially the same reference method" means a reference composition or method that contains substantially the same components or method steps in the absence of inventive components or method steps. In another exemplary embodiment, the term "substantially" in contexts such as "substantially the same reference composition" means a reference composition or method steps that contain substantially the same components or method steps, and wherein the inventive components or method steps are replaced by components or method steps common in the art.

[0046] The term "lithium-containing material" as used herein refers to any lithium-containing substance. This term may be mainly used to refer to naturally occurring minerals containing lithium values, including but not limited to silicates, fluorophosphates, borosilicates, aluminosilicates, phosphates (such as spodumene), lithium-containing micas, and lithium-containing clays. In some aspects, as disclosed herein, the lithium-containing material can be used as a naturally occurring ore. However, in other aspects, the lithium-containing material can be used as a concentrate.

[0047] Those skilled in the art will understand that lithium-containing materials can contain one or more naturally occurring lithium minerals, as they often occur together, for example, in pegmatite bodies. Several metals (such as Mn, Rb, and Cs) and other minerals (such as quartz, albite, feldspar, topaz, and beryl) may also be associated with these lithium minerals. Therefore, the term "lithium-containing material" encompasses high-grade ores and concentrates, as well as medium- and low-grade ores, concentrates, and their blends.

[0048] Exemplary lithium-containing materials include, but are not limited to, jadarite, spodumene and other pyroxenes, lepidolite, petalite and other lithium-containing silicates from the nepheline group of minerals, lithium glaucophane and other lithium-containing silicates from the amphibole group of minerals, lithiophilite, triphylite, lithium tourmaline and other tourmalines, chlorite, montmorillonite, lithium-containing mica and lithium-containing clay.

[0049] However, in other respects, lithium-containing materials may also refer to artificial materials containing at least a certain amount of lithium. For example, but not limited to, artificial (man-made) lithium-containing materials may include batteries, printed circuit boards, electronic materials, paints, etc.

[0050] In a further aspect, lithium-containing materials may also include coal and coal by-products, and waste streams from the mining and processing of minerals and oil shales, coal bottom clay, coal overburden, or any combination thereof.

[0051] In yet a further aspect, the lithium-containing materials include α-spodumene, lepidolite, lithium montmorillonite, jadarite, Li-rich clay, Li batteries, coal and coal by-products, and waste streams from the mining and processing of minerals and oil shales, coal bottom clay, coal overburden, recycled materials, or any combination thereof.

[0052] Although aspects of the present invention may be described and claimed in terms of specific statutory classes, such as system statutory classes, this is for convenience only, and those of ordinary skill in the art will understand that aspects of the present invention may be described and claimed in terms of any statutory class. Unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a particular order. Thus, in the claims or the specification, when a method claim does not expressly state that the steps are limited to a particular order, no order is to be inferred in any aspect. This applies to any possible basis of non-expression interpretation, including logical matters relative to step arrangement or operational flow, apparent meaning derived from grammatical organization or punctuation, or numerals or types of aspects described in the specification.

[0053] The present invention can be more readily understood by reference to the following detailed description of various aspects of the invention and the examples included therein, as well as reference to the accompanying drawings and their prior and subsequent descriptions.

[0054] Method

[0055] The present disclosure relates to a method for recovering lithium from lithium-containing materials. It should be understood that in some aspects, the methods disclosed herein are batch processes. In other aspects, the methods disclosed herein are continuous processes. It is also understood that hybrid processes may be used.

[0056] In certain aspects, the methods disclosed herein include heating a mixture of a lithium-containing material and a solid calcining agent provided in the form of a water-insoluble solid for a first predetermined time to form a solid composition comprising at least one water-soluble phase and at least one water-insoluble phase. In such aspects, the at least one water-soluble phase comprises a first amount of lithium and wherein the at least one water-insoluble phase comprises a second amount of lithium. In yet further aspects, the heating is performed at a heating temperature of about 100° C. to less than about 850° C.

[0057] In yet further aspects, the heating step can be performed at any temperature. In other aspects, the heating can be performed at a heating temperature of about 100°C to less than about 850°C (including exemplary values ​​of about 150°C, about 200°C, about 250°C, about 300°C, about 350°C, about 400°C, about 450°C, about 500°C, about 550°C, about 600°C, about 650°C, about 700°C, about 750°C, and about 800°C). In a further aspect, the heating can be performed at a heating temperature of less than about 850° C., less than about 800° C., less than about 775° C., less than about 750° C., less than about 725° C., less than about 700° C., less than about 675° C., less than about 650° C., less than about 625° C., less than about 600° C., less than about 575° C., less than about 550° C., less than about 525° C., less than about 500° C., less than about 475° C., less than about 450° C., less than about 425° C., less than about 400° C., less than about 375° C., less than about 350° C., less than about 325° C., less than about 300° C., less than about 275° C., less than about 250° C., less than about 225° C., less than about 200° C., less than about 175° C., less than about 150° C., or less than about 125° C. In a further aspect, the heating can be performed at any temperature between any two of the foregoing values.

[0058] In further aspect, described heating can be carried out at the temperature substantially the same as the melting point of roasting agent.In other aspect again, described heating can be carried out at the temperature higher than the melting point of roasting agent.And in other aspect, described heating can be carried out at the temperature lower than the melting point of roasting agent.In other exemplary non-limiting aspect again, if there is the mixture of compound, described heating can be carried out at the temperature close to or substantially equal to the eutectic point of mixture.However, it should also be understood that some mixtures in the mixture of roasting agent may not have eutectic point, or have one or more eutectic points.In such aspect, temperature can be selected to realize desired result.

[0059] In a further aspect, any of the method steps disclosed herein can also be carried out at a pressure of from about 0.1 MPa to about 20 MPa (including exemplary values of 0.5 MPa, about 1 MPa, about 2 MPa, about 3 MPa, about 3 MPa, about 4 MPa, about 5 MPa, about 6 MPa, about 7 MPa, about 8 MPa, about 9 MPa, about 10 MPa, about 11 MPa, about 12 MPa, about 13 MPa, about 14 MPa, about 15 MPa, about 16 MPa, about 17 MPa, about 18 MPa and about 19 MPa).

[0060] In some aspects, the heating step can be carried out at the elevated pressures disclosed. It should be understood that in certain aspects, increasing the pressure may allow the temperature in the heating step to be reduced.

[0061] It should be understood that any known heating method in the art can be used. In certain aspects, the heating step includes using a heating chamber that includes one or more heating sources effective to provide the desired heating temperature. It should be understood that the heating chamber can be a conventional oven, rotary kiln, furnace, thermal shock chamber, etc. Any heating source can be used, which can include gas or oil-based heaters, electric heaters, IR heaters, UV heaters, microwave heaters, solar heaters, etc. In a further aspect, the one or more heating sources include a microwave heating source. In such exemplary and non-limiting aspects, the microwave source can have a frequency between about 900 MHz and about 6 GHz (including exemplary values of about 915 MHz, 2.45 GHz or 5.8 GHz). However, any other permitted frequency within the disclosed range can also be used.

[0062] In a further aspect, the microwave source can have an energy between about 500 W and about 40 kW (including exemplary values of about 1 kW, about 5 kW, about 10 kW, about 15 kW, about 20 kW, about 25 kW, about 30 kW and about 35 kW).

[0063] In a still further aspect, the microwave source can have a frequency between about 900 MHz and about 6 GHz (including exemplary values of about 915 MHz, 2.45 GHz or 5.8 GHz), and an energy between about 500 W and about 40 kW (including exemplary values of about 1 kW, about 5 kW, about 10 kW, about 15 kW, about 20 kW, about 25 kW, about 30 kW and about 35 kW). Without being bound by any theory, it can be assumed that using a microwave heating source can improve lithium recovery. It can be further assumed that due to the internal heating characteristics of microwaves and the increased porosity of the host minerals, the temperature and sintering time required for the chemical reaction can be significantly reduced compared to the similar parameters when using conventional heating sources.

[0064] In some aspects, the formed solid composition can be washed and dried prior to any further processing steps. In such exemplary aspects, washing can allow for the removal of unreacted chemicals. However, it should be understood that if a washing step is present, the liquid phase from the washing process can be collected and any dissolved lithium present in the phase can be recovered. It should be understood that in some aspects, these optional washing and drying steps can also be carried out at the elevated pressures disclosed herein. However, in other aspects, the optional washing and drying steps can also be carried out under vacuum.

[0065] In a still further aspect, the formed solid composition can be further subjected to size reduction prior to any further processing steps.

[0066] In a yet further aspect, the formed solid composition can then be suspended in a first water aliquot for a second predetermined time to dissolve the at least one water-soluble phase and form a first suspension comprising a first solid phase and a first liquid phase. In such aspects, the first liquid phase can comprise a first portion of a first amount of lithium, while the first solid phase can comprise at least one water-insoluble phase containing a second amount of lithium. In a yet further aspect, the methods disclosed herein include recovering the first portion of the first amount of lithium from the first liquid phase. It should also be understood that the suspension step in any of the water aliquots disclosed herein can also be carried out at any of the elevated pressures disclosed herein. In a yet further aspect, the step of forming a suspension in a water aliquot can also be referred to as a water leaching step.

[0067] In certain aspects, the first water aliquot and / or any further water aliquots, when present, can include distilled water. In a yet further aspect, the first water aliquot and / or any further water aliquots, when present, can comprise a recycled first liquid phase and / or further liquid phases as described herein. In a yet further aspect, the recycled liquid phase can comprise an amount of lithium that was not recovered in a previous step. In still other aspects, the first water aliquot or a further water aliquot can comprise one or more additives configured to increase the solubility of lithium in water. In such exemplary and non-limiting aspects, the additives can participate in further phase changes of the solid composition formed after the heating step. In a yet further aspect, the one or more additives can comprise one or more salts. In such exemplary aspects, any of the water aliquots can comprise an electrolyte. In still other aspects, the additive can comprise a buffer. It should be understood that any additive that can affect phase changes in the lithium-containing material phase or increase the solubilization of lithium in water can be used. Similarly, if desired, any water aliquot can also comprise additives that improve the solubilization of one or more of aluminum, calcium, iron, silicon, sodium, or at least one rare earth element.

[0068] It should be understood that the recovery of the first portion of the first amount of lithium from the first liquid phase can be accomplished by any known method in the art without any limitation. In some exemplary and non-limiting aspects, the recovery may include forming lithium hydroxide, lithium chloride, and / or lithium carbonate by any method known in the art.

[0069] In yet a further aspect, prior to the recovery step, the first liquid phase can be analyzed for the presence of lithium. It should be understood that the analysis of lithium can be performed manually or automatically, for example, by removing a small portion of the liquid phase for elemental analysis.

[0070] It should also be understood that the recovery step may further include the step of separating the first liquid phase from the first solid phase. The separation may include any method known in the art. For example, the separation may include conventional separation techniques such as, for example, filtration, gravitational separation, centrifugation, etc. Those skilled in the art should understand that additives such as clarifying agents and / or thickening agents can be mixed into the suspension to separate the solid from the liquid, thereby facilitating their effective separation.

[0071] In yet a further aspect, the method may further include: i) suspending the first solid phase in a second aqueous aliquot for a third predetermined time to form a further suspension comprising a further solid phase and a further liquid phase; ii) recovering a further portion of the first amount of lithium from the further liquid phase; and iii) subjecting the further solid phase to steps i)-ii) if the further liquid phase is not substantially free of the further portion of the first amount of lithium in the further liquid phase. It should be understood that, in some aspects, the step of suspending the first solid phase in a second aqueous aliquot for additional water leaching of lithium may be optional. However, if this step is present, it can be repeated any number of times. Similarly, this step can also be performed at any elevated pressure disclosed herein. In some aspects, for example, these optional steps can be carried out as long as a significant amount of lithium can be recovered from each subsequent liquid phase. Also, and as disclosed above, the recovery step may include separating the further liquid phase from the further solid phase. When the further liquid phase is substantially free of lithium, the further liquid phase can be recycled to the first or second aqueous aliquot. It should also be understood that after recovering lithium or any other element disclosed herein from any one of the liquid phases disclosed herein, such a liquid phase can be recycled back into the process. Further, it should be understood that in such exemplary aspects, any of the aqueous aliquots disclosed herein can contain any of the additives described above.

[0072] In yet other aspects, if the process exists and if a further portion of the further liquid phase is substantially free of a first amount of lithium, the further liquid phase is recycled to the first aqueous aliquot. In such exemplary aspects, the further solid phase obtained in this step can then be collected for further processing. It should also be understood that the term "substantially free of" as used herein means that the liquid phase has less than about 1% lithium, less than about 0.5% lithium, less than about 0.3% lithium, less than about 0.1% lithium, less than about 0.05% lithium, or less than about 0.01% lithium. In yet further aspects, the term "substantially free of" can also mean less than 1,000 ppm lithium, less than 800 ppm lithium, less than 500 ppm lithium, less than 100 ppm lithium, or less than 50 ppm lithium.

[0073] However, it should be understood that, as discussed in detail above, the repeated exposure of each successive solid phase to the water leaching process as described is optional. In some aspects, after the first exposure of the solid mixture to the first aqueous aliquot, a first solid phase is formed and collected for further processing without any additional water leaching steps.

[0074] In some aspects, the lithium-containing material can include any natural and artificial materials known in the art that contain at least a certain amount of lithium, such as α-spodumene, lepidolite, hectorite, jadarite, Li-rich clay, Li batteries, recycled materials, coal and coal by-products, and waste streams from the mining and processing of minerals and oil shales, coal bottom clay, coal overburden, recycled materials, or any combination thereof. It should be understood that any natural or artificial materials known in the art can be used as the lithium-containing material of the present disclosure.

[0075] In some aspects, the lithium-containing material can be provided in its original form. However, in other aspects, the lithium-containing material can undergo some processing steps, such as, for example but not limited to, purification, size reduction, concentration, etc.

[0076] It should be understood that, for example, the purification step can include removing debris, unnecessary fillers, or materials that may have an adverse effect on further processing steps of the present disclosure. In some aspects, the purification step can include chemical purification, mechanical purification, or physical purification.

[0077] In yet other aspects, the process steps can further include concentrating the lithium-containing material before the heating step with a roasting agent.

[0078] It should be understood that the concentration step can include, for example, separating impurities from a grinder. Such separation can be (e.g., but not limited to) size separation, optical separation, gravity separation, magnetic separation, electrostatic separation, and / or flotation separation.

[0079] In some aspects, the lithium-containing material can be used as is. In other aspects, it can be size-reduced. Exemplary particle size distribution characteristics to be replicated can include a predetermined D (n) value, where (n) represents a mass percentage, such as 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100%. Thus, the D (n) value represents a finer particle size of (n) percentage of the mass therein. For example, the quantity D (100) represents a finer particle size of 100% of the mass therein. The quantity D (75) represents a finer particle size of 75% of the mass therein. The quantity D (50) is the median particle size of the mass, where 50% of the mass is finer. The quantity D (25) represents a finer particle size of 25% of the mass therein. The quantity D (10) represents a finer particle size of 10% of the mass therein.

[0080] In some exemplary aspects, the lithium-containing material can be size-reduced to D (80) in the range of about 20 μm to about 5 mm (including exemplary values of about 30 μm, about 40 μm, about 50 μm, about 60 μm, about 70 μm, about 80 μm, about 90 μm, about 100 μm, about 125 μm, about 150 μm, about 175 μm, about 200 μm, about 225 μm, about 250 μm, about 275 μm, about 300 μm, about 325 μm, about 350 μm, about 375 μm, about 400 μm, about 425 μm, about 450 μm, about 475 μm, about 500 μm, about 525 μm, about 550 μm, about 575 μm, about 600 μm, about 625 μm, about 650 μm, about 675 μm, about 700 μm, about 725 μm, about 750 μm, about 775 μm, about 800 μm, about 825 μm, about 850 μm, about 875 μm, about 900 μm, about 925 μm, about 950 μm, about 975 μm, about 1 mm, about 1.2 mm, about 1.5 mm, about 1.7 mm, about 2 mm, about 2.2 mm, about 2.5 mm, about 2.7 mm, about 3 mm, about 3.2 mm, about 3.5 mm, about 3.7 mm, about 4 mm, about 4.2 mm, about 4.5 mm and about 4.7 mm).

[0081] In a further aspect, the lithium-containing material can be milled and ground to a desired particle size in a dry milling process or a wet milling process by conventional techniques well known in the art.

[0082] In yet a further aspect, the lithium-containing material of any of the aspects disclosed above is mixed with a solid roasting agent.

[0083] It should be understood that the mixture can be formed by any method known in the art. For example, the lithium-containing material and the roasting agent can be crushed together, milled together, and / or blended. In still other aspects, the formed mixture is homogeneous. In some aspects, a blending silo can be used to obtain a homogeneous mixture, and the blending silo can include a recirculation pipeline to recirculate and blend the roasting agent within the lithium-containing material. In still other aspects, at least one blending silo can include a plurality of flow channels to assist in blending the roasting material within the lithium-containing material. In some aspects, blending may also help reduce the variation in particle size, thereby contributing to a more efficient roasting reaction between the lithium-containing material and the roasting agent. However, it should be understood that in some exemplary non-limiting aspects where the roasting agent is hydrophilic and can easily absorb moisture, blending can be carried out under an inert atmosphere or under reduced pressure so that moisture does not enter the mixture.

[0084] In still further aspects, the solid roasting agent can include one or more compounds containing one or more of alkali metals, alkaline earth metals, or ammonium-based compounds or combinations thereof. It should be understood that the compounds selected as the roasting agent can include salts, hydroxides, oxides, carbonates, sulfates, nitrates, chlorides, or any combination thereof. Further, it should be understood that these compounds can exist in pure form, but may also contain any amount of impurities that do not substantially affect the methods disclosed herein.

[0085] In still further aspects, the one or more compounds can include NaOH, Na 2 CO 3 , KOH, K 2 CO 3 , MgCO 3 , CaCO 3 , BaCO 3 , NaCl, KCl, CaCl 2 , MgCl 2 , NaNO 3 , KNO 3 , Ca(NO 3 ) 2 , Ba(NO 3 ) 2 , Mg(NO 3 ) 2 , Ca(OH) 2 , CaSO 4 , (NH 4 ) 2 SO 4 , Na 2 SO 4Or any combination thereof. However, in other respects, the roasting agent may comprise at least a certain amount of NaOH. In certain aspects, any of the compounds disclosed above may be used as a standalone roasting agent or in any combination with any of the compounds disclosed above. Again, it should be further understood that, in some exemplary non-limiting aspects, the mixing and use of the roasting agent may be carried out under an inert atmosphere or under reduced pressure to minimize the moisture content.

[0086] Without wishing to be bound by any theory, it is assumed that the use of the solid roasting agent as disclosed herein may react with the lithium-containing material to break bonds and render at least a portion of the lithium-containing material water-soluble, thereby allowing lithium to leach into the first aqueous aliquot.

[0087] It should be understood that, compared to conventional lithium recovery methods, the methods disclosed herein allow for a reduction processing step. For example, the methods disclosed herein allow the use of unprocessed lithium-containing materials and allow the solubilization of lithium therein at significantly lower temperatures and pressures than those used in conventional methods. Additionally, without wishing to be bound by any theory, it should be understood that the use of the solid roasting agent may minimize the use of corrosive materials and allow for direct reaction with the lithium-containing material. It should be understood that roasting with the solid roasting agent may reduce the use of highly corrosive liquids. In such aspects, the reaction allows for a phase transformation of the lithium-containing material and the formation of a water-soluble phase.

[0088] In yet further aspects, the lithium-containing material may include additional materials that are not lithium. In some aspects, these additional materials may include additional elements such as, for example, aluminum, calcium, iron, silicon, sodium, at least one rare earth material, transition metals (such as molybdenum), and the like.

[0089] In aspects of forming the first solid phase, the first solid phase may further include one or more of aluminum, calcium, iron, silicon, sodium, or at least one rare earth element. However, it is also understood that some of these additional materials may also dissolve in the first water aliquot and transfer to the first liquid phase. In such exemplary aspects, the first liquid phase may further contain a first amount of one or more of aluminum, calcium, iron, silicon, sodium, or at least one rare earth element. In certain aspects, the method further includes the step of recovering one or more of aluminum, calcium, iron, silicon, sodium, or at least one rare earth element. Any known method in the art for recovering these elements may be used. However, it should be further understood that if both aluminum and calcium are present, the first amount of aluminum is different from the first amount of calcium, and so on. In still further aspects, the first amount of each element among the elements disclosed above may be determined by its initial concentration in the lithium-containing material, the strength of its bonds within the lithium-containing material, and its solubility in water. In such exemplary aspects, the recovery rate of any additional element among the additional elements disclosed above that is different from Li in the first liquid phase or any further liquid phase present may be lower than the recovery rate of Li. If there is a step of treating the first solid phase with a further water aliquot to form a further solid phase and a further liquid phase, each of these phases may contain a further amount of one or more of aluminum, calcium, iron, silicon, sodium, or at least one rare earth element.

[0090] In still further aspects, any of the lithium-containing materials disclosed herein may be mixed with any of the roasting agents disclosed above in any desired ratio. In some aspects, the mixture may include a ratio of roasting agent to lithium-containing material between about 0.1:1 and about 10:1, where the ratio is calculated by the weight of the roasting agent divided by the weight of the lithium-containing material. Some exemplary non-limiting ratios may include about 0.1:1, about 0.2:1, about 0.3:1, about 0.4:1, about 0.5:1, about 0.6:1, about 0.7:1, about 0.8:1, about 0.9:1, about 1:1, about 2:1, about 3:1, about 4:1, about 5:1, about 6:1, about 7:1, about 8:1, about 9:1, and about 10:1.

[0091] In certain aspects, the first predetermined time is from about 0.5 seconds to about 24 hours (including exemplary values of about 1 s, about 5 s, about 10 s, about 30 s, about 1 min, about 5 min, about 15 min, about 30 min, about 45 min, about 1 h, about 2 h, about 5 h, about 10 h, about 15 h, or about 20 h).

[0092] In yet a further aspect, the first suspension and / or a further suspension when present is suspended in a respective water aliquot for a second predetermined time and / or a third predetermined time of from about 1 minute to about 72 hours (exemplary values including about 5 minutes, about 10 minutes, about 15 minutes, about 30 minutes, about 45 minutes, about 1 hour, about 5 hours, about 10 hours, about 15 hours, about 20 hours, about 24 hours, about 30 hours, about 36 hours, about 42 hours, about 48 hours, about 52 hours, about 60 hours and about 70 hours).

[0093] In yet a further aspect, the first suspension or a further suspension when present can be heated during the suspension time. In some aspects, the first suspension and / or a further suspension when present can be suspended in water at room temperature for a certain predetermined time and then heated. However, in other aspects, the first suspension and / or a further suspension when present can be suspended in hot water and respectively continue to be heated for a second predetermined time and / or a third predetermined time. In such aspects, the first suspension and / or the third suspension when present is heated at a temperature of from about 20 °C to about 100 °C (exemplary values including about 25 °C, about 30 °C, about 35 °C, about 40 °C, about 45 °C, about 50 °C, about 55 °C, about 60 °C, about 65 °C, about 70 °C, about 75 °C, about 80 °C, about 85 °C, about 90 °C and about 95 °C).

[0094] In yet a further aspect, the suspension step can further include mixing the first suspension or a further suspension when present. It should be understood that any known mixing technique in the art can be used. In some aspects, the mixing step can include stirring, agitating, blending, etc. The specific intensity of the mixing procedure can be determined by a person of ordinary skill in the art according to the desired result.

[0095] In yet a further aspect, the first portion of the first amount of lithium is at least 5% of all the lithium present in the lithium-containing material. In still other aspects, the first portion of the first amount of lithium is from about 5% to less than 100% of all the lithium present in the lithium-containing material (exemplary values including about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 95% and about 99%). In still other aspects, the sum of the first portion of the first amount of lithium and a further portion when present is from about 5% to less than 100% of all the lithium present in the lithium-containing material (exemplary values including about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 95% and about 99%).

[0096] In yet a further aspect, the method includes collecting the first solid phase or a further solid phase when present.

[0097] In still other aspects, the method further comprises: a) adding a first aliquot of an acid to the first solid phase or the further solid phase when present; b) suspending the first solid phase or the further solid phase when present in the amount of acid for a fourth predetermined time to form an additional suspension comprising an additional solid phase and an additional liquid phase, wherein the additional liquid phase comprises a first portion of the second amount of lithium and wherein the additional solid phase comprises a second portion of the second amount of lithium.

[0098] It should be understood that in certain aspects, aqueous leaching allows for a reduction in the amount of material present in the solid phase prior to the addition of the first acid aliquot, and thus this also allows for a reduction in the amount of acid required.

[0099] In yet further aspects, the method further comprises recovering a first portion of the second amount of lithium from the additional liquid phase. It should be understood that any known method for recovering lithium in the art may be used. Similarly, as disclosed above, lithium may be recovered as lithium hydroxide, lithium chloride, and / or lithium carbonate, or in any other acceptable form. Similar to the aspects disclosed above, the recovery step may also include first separating the additional liquid phase from the additional solid phase.

[0100] In yet further aspects, the fourth predetermined time is from about 1 min to about 72 hours (including exemplary values of about 5 min, about 10 min, about 15 min, about 30 min, about 45 min, about 1 h, about 5 h, about 10 h, about 15 h, about 20 h, about 24 h, about 30 h, about 36 h, about 42 h, about 48 h, about 52 h, about 60 h, and about 70 h).

[0101] In other aspects, the step of suspending the first solid phase or the further solid phase when present may further comprise the step of mixing the additional suspension. Any of the mixing methods disclosed above may be used for this purpose.

[0102] In still further aspects, the step of suspending the first solid phase or the further solid phase when present may further comprise maintaining the additional suspension at a temperature of from about 20 °C to about 300 °C (including exemplary values of about 25 °C, about 30 °C, about 35 °C, about 40 °C, about 45 °C, about 50 °C, about 55 °C, about 60 °C, about 65 °C, about 70 °C, about 75 °C, about 80 °C, about 85 °C, about 90 °C, about 95 °C, about 100 °C, about 115 °C, about 125 °C, about 150 °C, about 175 °C, about 200 °C, about 215 °C, about 225 °C, about 250 °C, and about 275 °C).

[0103] In a further aspect, the additional liquid phase may comprise a second amount of one or more of aluminum, calcium, iron, silicon, sodium, or at least one rare earth element. In such exemplary aspects, the method may further comprise recovering a second amount of one or more of aluminum, calcium, iron, silicon, sodium, or at least one rare earth element.

[0104] As discussed above, it should also be understood that the second amounts of any additional elements disclosed above are not necessarily the same. For example, if all or any of the elements aluminum, calcium, and silicon are present, the second amount of aluminum is different from the second amount of calcium or silicon, and so on. In a still further aspect, after the water leaching step, the second amount of each of the elements disclosed above may be higher than the first amount (or further amounts) of these elements. Again, without wishing to be bound by any theory, it is speculated that while the first roasting step may change the bonding of lithium in the lithium-containing material, making it water-soluble, it may not occur on other elements that may also be present in the lithium-containing material. In such aspects, these elements may remain in the water-insoluble phase and may only be leached by an acid leaching process as discussed herein. Further, the recovery rate of any of the additional elements disclosed herein may also depend on the concentration of the acid or the pH value of the liquid phase obtained after adding the acid.

[0105] In still other aspects, the disclosed method further comprises collecting an additional solid phase. In certain optional and exemplary aspects, the method may further comprise the following sequence of steps: i) adding a second aliquot of acid to the additional solid phase to form a further additional suspension comprising a further additional solid phase and a further additional liquid phase, wherein the further additional liquid phase optionally comprises a further portion of the second amount of lithium; ii) separating the further additional liquid phase and the further additional solid phase; if the further additional liquid phase comprises the further portion of the second amount of lithium, subjecting the further additional solid phase to steps i)-ii); if the further additional liquid phase is substantially free of the further portion of the second amount of lithium, recycling the further additional liquid phase to the first aliquot or the second aliquot of the acid. Similar to the aspects disclosed above, the further additional liquid phase may be separated from the further additional solid phase.

[0106] In some aspects, any aliquot of the acid present herein may also contain a certain amount of lithium that has not been recovered. In a further aspect, any aliquot of the acid present herein may contain a recycled liquid phase as described herein. In still other aspects, any aliquot of the acid present herein may contain one or more additives configured to increase the solubility of lithium in the acid. In such exemplary and non-limiting aspects, the additives may participate in further phase changes of the solid phase obtained after the water leaching step. In a further aspect, the one or more additives may comprise one or more salts. In still other aspects, the additive may comprise a buffer. It should be understood that any additive that may affect phase changes in the lithium-containing material or increase the solubility of lithium in the acid may be used. Similarly, if desired, the acid may also contain additives that improve the solubility of one or more of aluminum, calcium, iron, silicon, sodium, or at least one rare earth element.

[0107] In a still further aspect, the method may further comprise combining each further aliquot of the additional liquid phase and the further additional liquid phase. In such exemplary aspects, then all portions of a second amount of lithium may be recovered.

[0108] In a further aspect, the total lithium recovery in the water leachate and the acid leachate may be any value between about 5% and 100% (including exemplary values of about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 95%, about 99%, and about 99.99%).

[0109] In a further aspect, the total recovery of one or more of aluminum, calcium, iron, silicon, sodium, or at least one rare earth element from the water leachate and the acid leachate may be any value between about 5% and 100%, including exemplary values of about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 95%, about 99%, and about 99.99%.

[0110] It should be understood that any acid known in the art may be used. In a further aspect, the acid may include H 2 SO 4 、HCl、H 3 PO 4 、HNO 3Or any combination thereof. In some aspects, the acid is added in an amount and at a concentration to obtain an additional suspension having a pH value below 4, below 3.5, below 3, below 2.5, below 2, below 1.5 or even below 1. In a further aspect, the acid is added in an amount and at a concentration to obtain an additional suspension having a pH value from 0 to about 4 (exemplary values including about 0.5, about 1, about 1.5, about 2, about 2.5, about 3 and about 3.5). In yet a further aspect, any step in which at least one acid aliquot is added can also be carried out at an elevated pressure of about 0.1 MPa to about 20 MPa (exemplary values including about 0.5 MPa, about 1 MPa, about 2 MPa, about 3 MPa, about 3 MPa, about 4 MPa, about 5 MPa, about 6 MPa, about 7 MPa, about 8 MPa, about 9 MPa, about 10 MPa, about 11 MPa, about 12 MPa, about 13 MPa, about 14 MPa, about 15 MPa, about 16 MPa, about 17 MPa, about 18 MPa and about 19 MPa).

[0111] In still other aspects, any aliquot of the acid disclosed herein may also contain an additive configured to further improve lithium solubility and increase Li recovery rate.

[0112] Examples

[0113] The following examples are presented in order to provide a complete disclosure and description to those of ordinary skill in the art on how to prepare and evaluate the compounds, compositions, articles, devices and / or methods claimed herein, and are intended to be purely exemplary and not intended to limit the present disclosure. Efforts have been made to ensure the accuracy of the numbers (e.g., amounts, temperatures, etc.), but some errors and deviations should be taken into account.

[0114] Unless otherwise indicated, parts are parts by weight, temperature is in degrees Celsius or at ambient temperature, and pressure is equal to or close to atmospheric pressure.

[0115] Example 1

[0116] A representative sample of spodumene from North Carolina was obtained and concentrated by physical separation. The elemental characterization of the concentrated spodumene is shown in Table 1.

[0117] Table 1. Elemental concentration of concentrated spodumene

[0118]

[0119] A schematic diagram of process 102 is as Figure 2As shown. In step 102, 2 grams of a representative spodumene concentrate sample is mixed with 3 grams of NaOH (i.e., the NaOH:spodumene ratio is 1.5) in a chromium crucible, and then calcined in an oven at 318 °C (at a temperature substantially the same as the melting point of NaOH) for two hours (step 103). Then the sample is washed (step 103) and dried (step 105). Thereafter, the dried sample is transferred to a beaker, and 200 ml of water is added to the sample (step 106). The beaker is kept in a water bath at a temperature of 80 °C, and the solution is stirred with a overhead stirrer at 450 rpm for two hours (step 108).

[0120] Then the solution is filtered (step 110) to separate the leachate (112) and the solid sample (114). Then the solid sample is transferred back to the beaker again, 200 ml of 6M sulfuric acid is added to the beaker, and the solution is stirred at 450 rpm at room temperature for two hours (step 116). Then the solution is filtered to separate the solid and the leachate (step 118). The Li, Si, and Al contents of the leachates obtained from the water leaching and acid leaching processes and the remaining solids from the acid leaching (which are weighed, dried, and digested according to ASTM D6357-11) are analyzed to calculate the recovery rate values of the leaching process.

[0121] At the Energy and Environment Sustainability Laboratory (EESL) of the Penn State Institute of Energy and the Environment, the elemental contents of the leachates obtained during the water leaching and acid leaching processes were analyzed using inductively coupled plasma - optical emission spectrometry (ICP - OES). The leaching efficiency was determined based on the elemental recovery rate values, which represent the percentage of each element in the spodumene dissolved in the leachate (e.g., lithium recovery in water leaching = (amount of lithium dissolved in water / amount of lithium in the spodumene used in the experiment) x 100 = (lithium concentration in the leachate x volume of the leachate / lithium concentration in the spodumene x weight of the spodumene) x 100).

[0122] An exemplary process 200 for obtaining concentrated α - spodumene is as Figure 3 shown. The raw ore 202 is crushed (204), ground and deslimed (step 206), then the solids are separated from the liquid using flotation (208), and then magnetic separation (210) is carried out to obtain concentrated α - spodumene (212) with LiO 2 >6%.

[0123] To evaluate the importance of process parameters on lithium recovery through spodumene phase transformation and subsequent water leaching, a two - level statistical design procedure was carried out. The ranges of the parameter values evaluated are shown in Table 2.

[0124] Table 2. Range of parameter values studied in the level 2 test program

[0125]

[0126] The study found that, as Figure 5 shown, NaOH roasting is very effective in the phase transformation of α-spodumene to a soluble form, because during water leaching, about 70% of the Li is released into the water, and most of the remaining Li is released during acid leaching. Therefore, more than 95% of the Li is recovered by water leaching and acid leaching without the need for calcination at high temperatures. The results of Li, Si, and Al recovery are as Figure 5 shown. In addition to the high recovery rate of Li in water leaching, the low recovery rate of other elements in water leaching is another advantage of the proposed method, because it minimizes the downstream purification process. The results also show that a high Al recovery rate can also be achieved by acid leaching. Therefore, the current method can be used to maximize resource utilization and produce aluminum as a by-product.

[0127] Table 3 shows the average recovery rate values of Li, Al, and Si obtained from three repeated tests and the corresponding standard deviation values in the water leaching and acid leaching experiments, which correspond to Figure 5 .

[0128] Table 3. Element recovery rates

[0129]

[0130] To maximize the recovery rate of Li during water leaching and avoid any acid consumption in the lithium recovery process, a two-level design of experiments was carried out to evaluate the most effective parameters for the Li recovery rate in the water leaching process. As described in Table 2, the parameters of roasting and water leaching were examined. The results of the experimental design are listed in Table 4. The data show that under non-optimized conditions, the Li recovery rate is as high as 88%.

[0131] Table 4. Summary of independent parameters and measured values of response variables

[0132]

[0133] The analysis of variance (ANOVA) of the two-level design is shown in Table 5. The study found that the model is significant. The study found that the roasting temperature and NaOH: spodumene and their interaction are the most effective parameters, followed by the leaching time, leaching temperature, and stirring rate. These parameters will be used for process optimization to maximize the Li recovery rate in water leaching in the next study.

[0134] Example 2

[0135] Various roasting chemicals were also examined to determine the most effective chemical for converting spodumene mineral phase to water-soluble or acid-soluble phase through bond breaking. Additional chemicals tested included CaCl 2 、CaSO 4 、Ca(OH) 2 、(NH 4 ) 2 SO 4 、Na 2 CO 3 、NaCl、Na 2 SO 4 and KOH.

[0136] Table 5 Statistical significance of parameters and their related interactions obtained by analysis of variance of two-level experimental design

[0137]

[0138] The Li recovery procedure was similar to Example 1, where NaOH was replaced with one or more of the above-mentioned chemicals. For roasting, a representative sample of α-spodumene concentrate prepared as discussed below (the α-spodumene concentrate composition contained 25.1% Al 2 O 3 、0.66% CaO、0.73% Fe 2 O 3 、1.06% Na 2 O、65.7% SiO 2 and 5.7% Li 2 O) was uniformly mixed with each roasting reagent (3 g), then transferred to a zirconium crucible and heated in a conventional oven at the melting point of each chemical (e.g., Na 2 CO 3 : 851 °C, NaCl: 801 °C, Na 2 SO 4 : 885 °C and KOH: 36 °C) for 2 hours. However, it should also be understood that if roasting is carried out under elevated pressure or under microwave heating, these temperatures can be reduced.

[0139] For the most effective roasting chemicals, the experiment was repeated at least 3 times for statistical analysis. The results are as Figure 4 shown. It can be seen that NaOH showed the most effective Li recovery rate.

[0140] Example 3

[0141] Microwave roasting of spodumene in the presence of NaOH was further explored to minimize the energy required for roasting.

[0142] First, the heating efficiency of microwaves was tested on spodumene samples without any roasting agent (e.g., NaOH). It was found that there is a critical temperature (above which spodumene adsorbs microwaves) (above 800 °C). The results are as Figure 6 shown. However, it was also found that when spodumene is mixed with NaOH, the temperature rises rapidly because NaOH is a bipolar material and very rapidly adsorbs MW, melts, and reacts with spodumene.

[0143] Li recovery was carried out using a 2.45 GHz, 6 kW multimode batch system that operates at 1.5 kW at 400 °C. The ratio of α-spodumene to NaOH was 1:1, and the roasting time was 5 minutes. The results of such treatment are as Figure 7 shown. It can be seen that when roasting the samples with a microwave source, a Li recovery rate of over 90% after water leaching can be obtained.

[0144] Compared with traditional heating, cost savings, short processing time, direct, non-contact, selective, internal and volumetric heating, and a more controllable heating process are the practical benefits of the proposed microwave processing. Due to the microwave internal heating characteristics and the increased porosity of the host minerals, the temperature and sintering time required for chemical reactions are significantly lower and shorter than those of conventional roasting.

[0145] Example 4

[0146] The recovery rates of various elements in coal overburden or clay-rich shale were tested. The experiment was similar to Example 3 and was carried out using a 2.45 GHz, 6 kW multimode batch microwave system that operates at 1.5 kW at 400 °C. The results are shown in Figure 8 . As can be seen, the efficiency of leaching Li from clay materials with water is lower than that of leaching Li from α-spodumene sources with water. However, the overall recovery rate after water leaching and acid leaching increased significantly (compared to the values of non-roasted samples leached with strong acids). This result indicates that the process is highly efficient in recovering Li from clay sources (i.e., continuous chemical roasting (for converting aluminosilicate phases into water-soluble and acid-soluble phases), water leaching (to remove unreacted chemicals, recover the water-soluble phase, reduce the amount of material sent to the acidic circuit, and reduce acid consumption), and acid leaching (to recover the generated acid-soluble phase)).

[0147] A claim is not intended to cover and should not be construed as covering a means-plus-function or step-plus-function limitation, unless such a limitation is expressly recited in a given claim using the phrases "means for..." or "step for...".

[0148] In view of the processes and compositions described, certain more specifically described aspects of the present invention are described below. However, these specifically recited aspects should not be construed as having any limiting effect on any different claims that incorporate the different or more general teachings described herein, or that the "specific" aspects are in some way limited to a meaning different from the literal language and formula used therein.

[0149] Aspect:

[0150] Aspect 1: A method comprising: a) heating a mixture of a lithium-containing material provided in the form of a water-insoluble solid and a solid roasting agent for a first predetermined time to form a solid composition comprising at least one water-soluble phase and at least one water-insoluble phase, wherein the at least one water-soluble phase comprises a first amount of lithium and wherein the at least one water-insoluble phase comprises a second amount of lithium; wherein the heating is carried out at a heating temperature of from about 100 °C to less than about 850 °C; b) suspending the solid composition in a first aliquot of water for a second predetermined time, thereby dissolving the at least one water-soluble phase and forming a first suspension comprising a first solid phase and a first liquid phase, wherein the first liquid phase comprises a first portion of the first amount of lithium and wherein the first solid phase comprises the at least one water-insoluble phase containing the second amount of lithium; c) recovering the first portion of the first amount of lithium from the first liquid phase; and d) optionally: i) suspending the first solid phase in a second aliquot of water for a third predetermined time to form a further suspension comprising a further solid phase and a further liquid phase; ii) recovering a further portion of the first amount of lithium from the further liquid phase; and iii) subjecting the further solid phase to steps i)-ii) if the further liquid phase is not substantially free of the further portion of the first amount of lithium in the further liquid phase.

[0151] Aspect 2: The method according to Aspect 1, wherein step d) is present.

[0152] Aspect 3: The method according to any one of Aspects 1 to 2, wherein any one of steps a) to d) is carried out at a pressure of from about 0.1 MPa to about 20 MPa.

[0153] Aspect 4: The method according to any one of Aspects 1 to 3, wherein if the further liquid phase is substantially free of the further portion of the first amount of lithium, the further liquid phase is recycled to the first aliquot of water.

[0154] Aspect 5: The method according to any one of Aspects 1 to 4, wherein the roasting agent comprises one or more compounds containing one or more of alkali metals, alkaline earth metals or ammonium-based compounds or combinations thereof.

[0155] Aspect 6: The method according to aspect 5, wherein the one or more compounds include NaOH, Na 2 CO 3 , KOH, K 2 CO 3 , MgCO 3 , CaCO 3 , BaCO 3 , NaCl, KCl, CaCl 2 , MgCl 2 , NaNO 3 , LiNO 3 , KNO 3 , Ca(NO 3 ) 2 , Ba(NO 3 ) 2 , Mg(NO 3 ) 2 , Ca(OH) 2 , CaSO 4 , (NH 4 ) 2 SO 4 , Na 2 SO 4 or any combination thereof.

[0156] Aspect 7: The method according to aspect 5 or 6, wherein the one or more compounds comprise at least a certain amount of NaOH.

[0157] Aspect 8: The method according to any one of aspects 1 to 7, wherein the lithium-containing material includes α-spodumene, lepidolite, lithium montmorillonite, jadarite, lithium-rich clay, lithium batteries, coal and coal by-products, and waste streams from the mining and processing of minerals and oil shales, lithium batteries, recycled materials, or any combination thereof.

[0158] Aspect 9: The method according to any one of aspects 1 to 8, wherein the lithium-containing material further comprises one or more of aluminum, calcium, iron, silicon, sodium, or at least one rare earth element.

[0159] Aspect 10: The method according to aspect 9, wherein the first liquid phase further comprises a first amount of one or more of aluminum, calcium, iron, silicon, sodium, or at least one rare earth element.

[0160] Aspect 11: The method according to any one of aspects 1 to 10, wherein the mixture comprises a ratio of the roasting agent to the lithium-containing material between about 0.1:1 and about 10:1, wherein the ratio is calculated by the weight of the roasting agent divided by the weight of the lithium-containing material.

[0161] Aspect 12: The method according to any one of Aspects 1 to 11, wherein the heating includes heating a chamber, and the heating chamber includes one or more heating sources that effectively provide the heating temperature.

[0162] Aspect 13: The method according to Aspect 12, wherein the one or more heating sources include a microwave heating source.

[0163] Aspect 14: The method according to Aspect 13, wherein the microwave source has a frequency between about 900 MHz and about 6 GHz.

[0164] Aspect 15: The method according to Aspect 13 or 14, wherein the microwave source has an energy between about 500 W and about 30 kW.

[0165] Aspect 16: The method according to any one of Aspects 1 to 15, wherein the first predetermined time is about 0.5 seconds to about 24 hours.

[0166] Aspect 17: The method according to any one of Aspects 1 to 16, wherein the second predetermined time and / or the third predetermined time is about 1 minute to about 72 hours.

[0167] Aspect 18: The method according to any one of Aspects 1 to 17, wherein the suspension includes heating the first suspension and / or the further suspension when present.

[0168] Aspect 19: The method according to Aspect 18, wherein the heating of the first suspension or the further suspension when present is carried out at a temperature between about 20 °C and about 100 °C.

[0169] Aspect 20: The method according to any one of Aspects 1 to 19, wherein the suspension includes mixing the first suspension or the further suspension when present.

[0170] Aspect 21: The method according to any one of Aspects 1 to 20, wherein the first portion of the first amount of lithium is at least 5% of all the lithium present in the lithium-containing material.

[0171] Aspect 22: The method according to any one of Aspects 1 to 21, wherein the first portion of the first amount of lithium is about 5% to less than 100% of all the lithium present in the lithium-containing material.

[0172] Aspect 23: The method according to any one of Aspects 1 to 22, wherein the sum of the first portion of the first amount of lithium and the further portion is about 5% to less than 100% of all the lithium present in the lithium-containing material.

[0173] Aspect 24: The method according to any one of aspects 1 to 23, further comprising collecting the first solid phase or the further solid phase when present.

[0174] Aspect 25: The method according to aspect 24, further comprising: a) adding a first aliquot of an acid to the first solid phase or the further solid phase when present; and b) suspending the first solid phase or the further solid phase when present in the amount of acid for a fourth predetermined time to form an additional suspension comprising an additional solid phase and an additional liquid phase, wherein the additional liquid phase comprises a first portion of the second amount of lithium and wherein the additional solid phase comprises a second portion of the second amount of lithium.

[0175] Aspect 26: The method according to aspect 25, further comprising recovering the first portion of the second amount of lithium from the additional liquid phase.

[0176] Aspect 27: The method according to aspect 25 or 26, wherein the fourth predetermined time is from about 1 minute to about 72 hours.

[0177] Aspect 28: The method according to any one of aspects 25 to 27, wherein b) further comprises mixing the additional suspension.

[0178] Aspect 29: The method according to any one of aspects 25 to 28, wherein b) further comprises maintaining the additional suspension at a temperature of from about 20 °C to about 300 °C.

[0179] Aspect 30: The method according to any one of aspects 25 to 29, wherein the additional liquid phase comprises one or more of a second amount of aluminum, calcium, iron, silicon, sodium or at least one rare earth element.

[0180] Aspect 31: The method according to aspect 30, further comprising recovering one or more of the second amount of aluminum, calcium, iron, silicon, sodium or at least one rare earth element.

[0181] Aspect 32: The method according to any one of aspects 25 to 31, comprising collecting the additional solid phase.

[0182] Aspect 33: The method according to aspect 33 further comprises the following sequence of steps: i) adding a second aliquot of the acid to the additional solid phase to form a further additional suspension comprising a further additional solid phase and a further additional liquid phase, wherein the further additional liquid phase optionally comprises a further portion of the second amount of lithium; ii) separating the further additional liquid phase and the further additional solid phase; if the further additional liquid phase comprises the further portion of the second amount of lithium, subjecting the further additional solid phase to steps i)-ii); if the further additional liquid phase is substantially free of the further portion of the second amount of lithium, recycling the further additional liquid phase to the first aliquot or the second aliquot of the acid.

[0183] Aspect 34: The method according to aspect 33 further comprises combining each of the additional liquid phase and the further additional liquid phase.

[0184] Aspect 35: Recovering all portions of the second amount of lithium according to the method of aspect 34.

[0185] Aspect 36: The method according to any one of aspects 25 to 35, wherein the acid comprises H 2 SO 4 、HCl、H 3 PO 4 、HNO 3 or any combination thereof.

[0186] Aspect 37: The method according to any one of aspects 25 to 36, wherein any one of steps a)-b) and / or i)-ii) is performed at a pressure of from about 0.1 MPa to about 20 MPa.

Claims

1. A method, which comprises: a) heating a mixture of a lithium-containing material provided in the form of a water-insoluble solid and a solid roasting agent for a first predetermined time to form a solid composition comprising at least one water-soluble phase and at least one water-insoluble phase, wherein at least one water-soluble phase comprises a first amount of lithium, and wherein at least one water-insoluble phase comprises a second amount of lithium; wherein the heating is carried out at a heating temperature of 100°C to less than 850°C; b) suspending the solid composition in a first water aliquot for a second predetermined time, thereby dissolving at least one water-soluble phase and forming a first suspension comprising a first solid phase and a first liquid phase, wherein the first liquid phase comprises a first portion of the first amount of lithium, and wherein the first solid phase comprises at least one water-insoluble phase containing the second amount of lithium; Among them, the roasting agent includes NaOH, NaCl, Na 2 SO 4 、Na 2 CO 3 、KOH, KCl, K 2 CO 3 、MgCO 3 、CaCO 3 、BaCO 3 、CaCl 2 、MgCl 2 、NaNO 3 、KNO 3 、Ca(NO 3 ) 2 、Ba(NO 3 ) 2 、Mg(NO 3 ) 2 、Ca(OH) 2 、CaSO 4 、(NH 4 ) 2 SO 4 or any combination thereof; and wherein the mixture comprises a ratio of roasting agent to lithium-containing material of 0.1:1 to 10:1, wherein the ratio is calculated by the weight ratio of the roasting agent to the weight of the lithium-containing material.

2. The method according to claim 1, wherein the method further comprises step c) i) suspending the first solid phase in a second water aliquot for a third predetermined time to form a further suspension comprising a further solid phase and a further liquid phase; ii) subjecting the further solid phase to step i) if the further liquid phase is not substantially free of a further portion of the first amount of lithium in the further liquid phase.

3. The method according to claim 2, wherein any of steps a) to c) is carried out at a pressure of 0.1 MPa to 20 MPa.

4. The method according to claim 2, wherein if the further liquid phase is substantially free of a further portion of the first amount of lithium, the further liquid phase is recycled to the first water aliquot.

5. The method according to claim 1, wherein the roasting agent comprises at least a certain amount of NaOH.

6. The method according to any one of claims 1 to 2, wherein the lithium-containing material comprises α-spodumene, lepidolite, lithium muscovite, petalite, hectorite, triphylite, eucryptite, tourmaline, chlorite, montmorillonite, Li-containing mica, jadarite, lithiophilite, Li-rich clay, Li battery, waste streams from the mining and processing of coal and coal by-products, and minerals and oil shale, coal bottom clay, coal overburden, or any combination thereof.

7. The method according to any one of claims 1 to 2, wherein the lithium-containing material further comprises one or more of the following elements: aluminum, calcium, iron, silicon, sodium, rubidium, cesium, or at least one rare earth element.

8. The method according to claim 7, wherein the first liquid phase further comprises a first amount of one or more of the following elements: aluminum, calcium, iron, silicon, sodium, rubidium, cesium, or at least one rare earth element.

9. The method according to any one of claims 1 to 2, wherein the heating comprises a heating chamber, and the heating chamber comprises one or more heating sources that effectively provide the heating temperature.

10. The method according to claim 9, wherein one or more heating sources comprise a microwave heating source.

11. The method according to claim 10, wherein the microwave heating source has a frequency of 900 MHz to 6 GHz and an energy of 500 W to 30 kW.

12. The method according to any one of claims 1 to 2, wherein the first predetermined time is from 0.5 seconds to 24 hours.

13. The method according to any one of claims 1 to 2, wherein the second predetermined time and / or the third predetermined time is from 1 minute to 72 hours.

14. The method according to any one of claims 1 to 2, wherein the suspension comprises heating the first suspension and / or a further suspension, when present, at a temperature of 20 °C to 100 °C.

15. The method according to any one of claims 1 to 2, wherein the suspension comprises mixing the first suspension or a further suspension, when present.

16. The method according to any one of claims 1 to 2, wherein the first part of the first amount of lithium is from 5% to less than 100% of all the lithium present in the lithium-containing material.

17. The method according to any one of claims 1 to 2, wherein the sum of the first part and a further part of the first amount of lithium is from 5% to less than 100% of all the lithium present in the lithium-containing material.

18. The method according to any one of claims 1 to 2, further comprising collecting the first solid phase or a further solid phase, when present.

19. The method according to claim 18, which further comprises: d) adding a first aliquot of an acid to the first solid phase or a further solid phase, when present; and e) suspending the first solid phase or a further solid phase, when present, in the amount of acid for a fourth predetermined time to form an additional suspension comprising an additional solid phase and an additional liquid phase, wherein the additional liquid phase comprises a first part of a second amount of lithium, and wherein the additional solid phase comprises a second part of the second amount of lithium.

20. The method according to claim 19, wherein the fourth predetermined time is from 1 minute to 72 hours.

21. The method according to claim 19, wherein e) further comprises mixing the additional suspension.

22. The method according to claim 19, wherein e) further comprises maintaining the additional suspension at a temperature of 20 °C to 300 °C.

23. The method according to claim 19, wherein the additional liquid phase comprises a second amount of one or more of the following elements: aluminium, calcium, iron, silicon, sodium, rubidium, caesium or at least one rare earth element.

24. The method according to claim 23, further comprising recovering a second amount of one or more of the following elements: aluminium, calcium, iron, silicon, sodium, rubidium, caesium or at least one rare earth element.

25. The method according to claim 19, which comprises collecting the additional solid phase.

26. The method according to claim 25, which further comprises the steps in the following order: iii) adding a second aliquot of an acid to the additional solid phase to form a further additional suspension comprising a further additional solid phase and a further additional liquid phase, wherein the further additional liquid phase optionally comprises a further part of the second amount of lithium; iv) separating the further additional liquid phase and the further additional solid phase; If a further additional liquid phase comprises a further portion of the second amount of lithium, subject the further additional solid phase to steps iii)-iv) further; and If the further additional liquid phase is substantially free of the further portion of the second amount of lithium, recycle the further additional liquid phase to the first aliquot or the second aliquot of the acid.

27. The method according to claim 26, further comprising combining each further additional liquid phase in the additional liquid phase and the further additional liquid phase.

28. The method according to claim 19, wherein the acid comprises H 2 SO 4 , HCl, H 3 PO 4 , HNO 3 or any combination thereof.

29. The method according to claim 19, wherein any of steps d) to e) is carried out at a pressure of 0.1 MPa to 20 MPa.

30. The method according to claim 26, wherein any of steps iii) to iv) is carried out at a pressure of 0.1 MPa to 20 MPa.

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