Method and apparatus for extraction of lithium from lithium-containing ceramics

Abstract

A method including pretreating ground lithium-containing ceramics to form alkali coated ceramics, leaching the alkali coated ceramics to form a leachate comprising a filtrate and a solid residue, preferentially extracting lithium from the filtrate to form a lithium rich solution and a raffinate, precipitating a crude lithium carbonate from the lithium rich solution and purifying the crude lithium carbonate to produce a battery grade lithium carbonate. A method including leaching a slurry comprising lithium-containing ceramics, water, a strong base, and an alkaline earth metal oxide / hydroxide at a pressure ranging from 0 to 1450 psi and at a temperature ranging from 100 to 500°C to form a leached slurry comprising a liquid filtrate and a solid residue, processing the liquid filtrate to recover a lithium-rich organic solution, and processing the lithium-rich organic solution to produce a battery-grade lithium compound and sodium sulfate.

Description

APPLICATIONFORUNITED STATES LETTERS PATENTTITLE : METHOD AND APPARATUS FOR EXTRACTION OFLITHIUM FROM LITHIUM-CONTAINING CERAMICSINVENTOR(S): Yang XiaJacob Xc JinQi LiDimitri Athan BikosMETHOD AND APPARATUS FOR LITHIUM EXTRACTION FROM LITHIUM-CONTAININGCERAMICSBACKGROUND

[0001] Lithium is a crucial element in modern technology and industry due to its unique properties and wide range of applications. It is essential in the production of lithium-ion batteries, which power portable electronic devices, electric vehicles, and renewable energy storage systems, making it vital for the advancement of clean energy technologies. Additionally, lithium compounds are used in the treatment of mood disorders, such as bipolar disorder, and in various industrial applications, including the manufacture of ceramics, glass, and lubricants. The growing demand for lithium in these diverse fields underscores its importance in driving technological innovation and supporting sustainable development.

[0002] Lithium is a critical raw material used for a wide range of applications, such as fabrication of batteries, glass and ceramics, lubricants and greases, polymers, and pharmaceuticals. As of 2023, the lithium-ion battery sector accounts for about 45% of global lithium consumption, while the glass and ceramics sector accounts for 27% of the lithium consumption with the rest for lubricants, greases, polymer production and others. Lithium is essential in the glass and ceramics industry due to its ability to enhance material properties. In glass production, lithium compounds improve strength, durability, and thermal shock resistance, which is crucial for specialty glasses like ovenware and laboratory glassware.

[0003] The addition of lithium increases the glass melt rate and lowers the viscosity and the melt temperature, resulting in high output, energy savings, and molding benefits. In addition, lithium lowers firing temperatures and thermal expansion and increases the strength of ceramic bodies. Lithium lowers the melting temperature of glazes, reducing energy consumption, and improves mechanical strength and thermal expansion resistance, benefiting products such as tiles and sanitary ware. This makes lithium vital for producing high-quality, durable, and energy-efficient glass and ceramic materials. These beneficial effects explain the substantial consumption of lithium in the glass and ceramics sector. Unfortunately, due to the inherent brittleness of glass and ceramics, approximately 30%of materials end up as scraps during manufacturing. These discarded materials are typically consigned to landfills, resulting in a significant loss of valuable resources. Given all these facts, it becomes abundantly clear that efficient recycling of lithium from waste glass and ceramics can create a profound impact on the entire lithium supply chain. Therefore, it is necessary to recycle lithium from scraps generated during glass-ceramics manufacturing processes and spent glass-ceramics. Due to the stable structure of glass ceramics, direct leaching with acid and / or base is inefficient in dissolving lithium from it. Therefore, high-temperature roasting at above 1000 °C has been proposed to enhance the extraction of lithium from glass-ceramics. This method suffers from the disadvantage of being extremely energy intensive.

[0004] It is imperative to recognize that while lithium recycling from spent batteries has received considerable attention, the parallel endeavor involving waste glass and ceramics remains relatively unexplored. In addition to glass-ceramics, there are many other types of lithium-containing silicate materials. As an example, lithium clays, also known as lithium-rich clay deposits, are geological formations that contain significant concentrations of lithium within their structure. These clays are typically found in sedimentary deposits and are characterized by their high lithium content relative to other clay minerals. As another example, spodumene is a mineral composed of lithium aluminum inosilicate, LiAl(SiO3)2, and is one of the primary sources of lithium due to its high lithium content. It is typically found in pegmatite formations, which are coarsegrained igneous rocks often associated with granite.

[0005] Similar to glass-ceramics, the existing processing methods of these lithium-containing silicate materials suffer from the disadvantages of being energy extensive and cost ineffective. For instance, in the spodumene industry, concentrated spodumene is roasted in a kiln at high temperatures (around 1000 °C) to convert a-spodumene to P-spodumene, which is more soluble and easier to digest in subsequent processing steps. After roasting, the spodumene is subjected to digestion with sulfuric acid to dissolve lithium into solution as lithium sulfate.

[0006] This untapped domain offers a promising opportunity to not only bolster the sustainability of lithium sourcing but also to establish a closed-loop system within the glass and ceramicmanufacturing and consumption cycle. By doing so, we not only reduce waste and resource depletion but also fortify the resilience and sustainability of these vital industries.

[0007] Several studies have explored lithium recycling from lithium aluminum silicate (LAS) glass-ceramics, with a primary focus on methods such as direct alkali leaching, or roasting and leaching. In former method, LAS glass-ceramics particles are directly reacted with a sodium hydroxide solution, whereas the latter method involves initially roasting the glassceramics particles at 900-1,000 °C, followed by leaching with suitable lixiviants. While these studies generated some promising results, for example, approximately 70% of lithium was leached using 2 mol / L NaOH at 100 °C with a duration of 12 hours, however, there are several issues and challenges associated with these prior arts.

[0008] LAS glass-ceramics typically contain 3-6% Li2O, 18-25% A12O3, and 58-75% SiO2. Consequently, recycling of Li only creates part of the value, and significant benefits can be created by simultaneously recycling Li, Al, and Si from the material. Unfortunately, none of the existing methods have taken this comprehensive approach into consideration. Other issues and challenges with existing methods are limited lithium recovery efficiency and lithium purification, energy consumption and cost. The purification of Li from the complex leachate was not addressed in prior arts. Roasting pretreatment at 900-1,000 °C temperature was energy extensive and costly. Overall, there remains a need for innovative technologies to efficiently concentrate and purify lithium from aqueous solutions, especially those with low lithium concentrations, and to produce battery-grade lithium hydroxide.BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 an overall process flow diagram of three modules for lithium and other value- added components recovery from lithium aluminum silicate ceramics (silicates and aluminosilicates).

[0010] FIG. 2 is a process flow diagram of recovering lithium and other valuable metals from lithium aluminum silicate ceramics in accordance with embodiments disclosed herein.

[0011] FIG. 3 A is Eh-pH diagram of 1 mol / L Al at room temperature.

[0012] FIG. 3B is Eh-pH diagram of 1 mol / L Si at room temperature.

[0013] FIG. 4 is an example of SEM image and EDS data of recovered SiCh product using the method disclosed herein.

[0014] FIG. 5 is an example of SEM image and EDS data of recovered Na2CO3 product using the method disclosed herein.

[0015] FIG. 6 is a process flow diagram for battery-grade lithium compound production from silicate materials.DETAILED DESCRIPTION

[0016] The embodiments disclosed herein describe a process that integrates three distinct modules along with several innovative technologies, all designed to efficiently recover lithium and other valuable components from glass-ceramics. The source material for this process can be, for example, the scraps generated during the manufacturing of glassceramics or post-consumer waste glass-ceramics. Additionally, it is noteworthy to point out that the method can also be employed to extract lithium from other silicate and aluminum silicate materials, glass-ceramics, petalite (LiAl(Si20s)2), lepidolite (K(Li,Al)3(Al,Si,Rb)4Oio(F,OH)2), spodumene (LiAl(SiO3)2), and lithium-bearing clay minerals.

[0017] The present disclosure presents a method for lithium and other valuable components recovery from used and scrap ceramics, including leaching of the ceramics, resulting in a lithium-rich solution and a raffinate solution; extracting and purifying lithium from the lithium-rich solution, and extracting and purifying A12O3, SiO2, and Na2CO3and other value components from the raffinate solution.

[0018] The method may also include applying a pretreatment by coating the ceramics particles with an alkaline or salt solution, roasting the coated particles, followed by leaching, resulting in a leachate containing lithium, silicon, aluminum, other valuable components, separating the lithium and other valuable components in the leachate solution into a lithium-rich phase solution and a raffinate phase solution, extracting andpurifying lithium from the lithium-rich solution by means of precipitation and separation; and extracting and recovering AI2O3, SiCh and alkali carbonate from the raffinate solution by means of precipitation, separation and evaporation.

[0019] The present disclosure also presents a process for producing battery-grade lithium compounds from lithium-containing silicate materials, including mixing a lithium- containing silicate material with water, a strong base, and an alkaline earth metal oxide / hydroxide, resulting in a slurry, conducting high-pressure leaching on the slurry to dissolve lithium from the silicate material, subjecting the slurry after high-pressure leaching to solid / liquid separation, resulting in the first lithium-containing solution and the first solid residue, removing impurities from the first solution through appropriate methods, leading to the second solution, concentrating and purifying lithium from the second solution through solvent extraction and scrubbing, leading to the third solution and the fourth solution, respectively, as well as an organic phase loaded with lithium, feeding the lithium-loaded organic phase to battery-grade lithium compound production to produce battery-grade lithium carbonate or hydroxide, alongside the generation of the first condensed water, washing the first solid residue to recover lithium, resulting in the generation of the second solid residue and the fifth solution, drying the second solid residue to obtain a final solid product and the second condensed water, directing the third solution to the slurry mixing and / or the washing steps, directing the fourth solution to the solvent extraction step, directing the fifth solution to the slurry mixing step, and directing the first and second condensed water to the washing and / or scrubbing steps.

[0020] The lithium-containing silicate materials may originate from different sources, such as glass-ceramics, silicate minerals, industrial silicate wastes, and lithium containing natural minerals, such as spodumene, lepidolite. The silicate materials may be prepared first through crushing and / or grinding to reduce to an appropriate particle size range, such as below 50 mesh, preferred particle size range is below 100 mesh. The strong base includes, but is not limited to, sodium hydroxide and potassium hydroxide. The alkaline earth metal oxide / hydroxide includes, but is not limited to, calcium oxide, calcium hydroxide, magnesium oxide, and magnesium hydroxide.

[0021] The high-pressure leaching process occurs at about 0 psi to about 1450 psi and about 100 °C to 500 °C. The high-pressure leaching process may last for about 1 second to about 12 hours. The impurities present in the first solution may be eliminated through a single method or a combination of different methods, such as selective precipitation, selective adsorption, and membrane-based methods.

[0022] The solvent extraction step may occur in multiple stages configured in a countercurrent, co-current, or a combination of both arrangements. A variety of extractants is available in the solvent extraction step, such as di-(2-ethylhexyl) phosphoric acid, tri-n- butyl phosphate, tricaprylmethylammonium chloride, an ionic liquid, or a synergistic extractant system. The scrubbing step may occur in multiple stages configured in a counter- current, co-current, or a combination of both arrangements. The scrubbing step may use water, such as tap water or deionized water, and / or dilute acid as the aqueous phase.

[0023] The battery-grade lithium carbonate can be produced from the lithium-loaded organic phase by sulfuric acid stripping, followed by lithium carbonate precipitation and carbonate refinement. The battery-grade lithium carbonate can be produced from the lithium-loaded organic phase by mixing with carbon dioxide, followed by solid / liquid separation and de-oiling. The battery-grade lithium carbonate can be produced from the lithium-loaded organic phase by mixing with carbon dioxide, followed by phase separation, de-oiling, and mechanical vapor recompression. The battery-grade lithium hydroxide can be produced from the lithium-loaded organic phase by hydrogen peroxide stripping, followed by de-oiling, de-contamination, and further purification.

[0024] The solid residue may be washed by re-dispersing the solid particles in solution followed by solid / liquid separation. The washing may be conducted in multiple staged configured in a counter-current arrangement.

[0025] In one aspect, embodiments disclosed herein relate to a method for recovering lithium and other valuable components from lithium containing ceramics. The method includes pretreating ground lithium-containing ceramics to form alkali coated ceramics, leaching the alkali coated ceramics to form a leachate comprising a filtrate and a solid residue, preferentially extracting lithium from the filtrate to form a lithium rich solutionand a raffinate, precipitating a crude lithium carbonate from the lithium rich solution, and purifying the crude lithium carbonate to produce a battery grade lithium carbonate. The method may also include extracting and purifying AI2O3, SiCh, ISfeCCh and other value components from the raffinate with staged precipitation.

[0026] As described above, the method may include pretreating the ground lithium containing ceramics to form alkali coated ceramics. The lithium containing ceramics may include but are not limited to glass ceramics, post-consumer waste glass ceramics, silicates, aluminum silicate materials, petalite (LiAl(Si20s)2), lepidolite (K(Li,Al)a(Al,Si,Rb)4Oio(F,OH)2), spodumene (LiAl(SiO3)2), and lithium-bearing clay minerals. According to one or more embodiments, pretreating the ground lithium containing ceramics may include soaking the ground lithium-containing ceramics in an alkali solution to form uniformly coated ground ceramics and alkali roasting the uniformly coated ground ceramics thereby forming the alkali coasted ceramics. The uniformly coated ground ceramics may be roasted at a temperature ranging from 200 to 500°C, such as from a lower limit of any of 200, 225, 250, 275, 300 or 325°C to an upper limit of any one of 350, 375, 400, 425, 450 or 500°C, where any lower limit may be mathematically paired with any upper limit.

[0027] As described above, the method may include leaching the alkali coated ceramics to form a leachate that includes a filtrate and a solid residue. According to one or more embodiments, leaching the alkali coated ceramics may include leaching the alkali coated ceramics with water to produce a first portion of lithium, leaching the alkali coated ceramics with a dilute acid to produce a second portion of lithium, and filtering the leachate obtained from both leaching steps to form the filtrate and the solid residue. The dilute acid may include but is not limited to the hydrochloric acid solutions and sulfuric acid solutions. The concentration of the dilute acid may range from a lower limit of any one of 1, 5, 10, 20, 25, 50, 75 and 100 g / L to an upper limit of any one of 50, 75, 100, 125, 150, 175 and 200 g / L where any lower limit may be paired with any mathematically compatible upper limit. The amount of the water used to leach the alkali coated ceramics may be expressed as a mass ratio of water to solids ranging from 1: 1 to 10: 1

[0028] According to the method described above, the method may also include preferentially extracting lithium from filtrate to form a lithium rich solution and a raffinate. According to one or more embodiments, preferentially extracting lithium from the filtrate to form the lithium rich solution may include separating lithium with a liquid extractant and / or separating lithium with an adsorbent resin. Once the adsorbent resin absorbs the lithium, the lithium may be subsequently desorbed to provide the lithium rich solution. According to one or more embodiments, the extractant may be an alkaline extractant and used in an amount relative to the amount of lithium found in the lithium rich solution. Further, the adsorbent resin may be an aluminum-based resin. As a nonlimiting example, the lithium may be adsorbed by the Al-based resin and then desorbed using any suitable ion exchange method.

[0029] As referred to above, the method may include precipitating a crude lithium carbonate from the obtained lithium rich solution. The crude lithium carbonate may be precipitated using sodium carbonate.

[0030] Following the precipitation of the crude lithium carbonate, the method may include purifying the crude lithium carbonate to produce a battery grade lithium carbonate. Purification of the crude lithium carbonate may include dissolving the crude lithium carbonate in the presence of a solution that includes carbon dioxide to form a lithium bicarbonate solution, filtering undissolved components from the lithium bicarbonate solution and removing the carbon dioxide from the lithium bicarbonate solution to isolate a battery grade lithium carbonate. During purification, the carbon dioxide may be used to adjust the pH level to the levels suitable to precipitate different aluminum and silicon species. As a non-limiting example, as shown in FIGs. 3A and 3B, an amount of carbon dioxide may be added to adjust the pH and to make Al(0H)3 or H2SiO3 precipitate. Once the carbon dioxide is removed, a battery grade lithium carbonate of greater than 99.5% may be isolated.

[0031] As discussed above, the method may also include extracting and purifying AI2O3, SiO2, Na2CO3 and other value components from the raffinate with staged precipitation. According to one or more embodiment, the other valuable components may include but are not limited to CaSiCh, AI2O3, SiCh and any suitable reagent that may be used upstreamof the process, such as during pretreatment. The step of extracting and purifying AI2O3, SiCh, Na2CC>3 and other value components from the raffinate with staged precipitation may include performing staged carbonation on the raffinate or treating the raffinate with a mineral acid. Performing staged carbonation may include treating the raffinate with carbon dioxide at least once to reduce a pH of the raffinate to a target pH, filtering the raffinate to recover solid AI2O3, SiCh, and liquid filtrate, and evaporating the liquid filtrate to recover the alkali carbonate such as sodium carbonate (Na2CO3). As a non-limiting example, the pH of the raffinate prior to treating with carbon dioxide may be above 13, where both Al and Si are soluble in the solution. Adding a suitable amount of carbon dioxide to lower the pH in the range to selectively precipitate the Al and Si species may be used to recover the solid AI2O3, SiCh.

[0032] In another aspect, embodiments disclosed herein relate to a high pressure leaching method that includes leaching a slurry including lithium-containing ceramics, water, a strong base, and an alkaline earth metal oxide / hydroxide at a pressure ranging from 0 to 1450 psi and at a temperature ranging from 100 to 500°C to form a leached slurry including a liquid filtrate and a solid residue, processing the liquid filtrate to recover a lithium-rich organic solution, and processing the lithium-rich organic solution to produce a battery-grade lithium compound and sodium sulfate.

[0033] As described above, the method may include leaching a slurry including lithium- containing ceramics, water, a strong base, and an alkaline earth metal oxide / hydroxide to form a leached slurry including a liquid filtrate and a solid residue. As described above, the lithium containing ceramics include but are not limited to glass ceramics, postconsumer waste glass ceramics, silicates, aluminum silicate materials, petalite (LiAl(Si20s)2), lepidolite (K(Li,Al)a(Al,Si,Rb)4Oio(F,OH)2), spodumene (LiAl(SiO3)2), and lithium-bearing clay minerals. The lithium containing ceramics may be prepared through crushing and / or grinding to reduce to a particle size below 50 mesh. According to one or more embodiments, the strong base includes but is not limited to sodium hydroxide, potassium hydroxide, and combinations thereof. The alkaline earth metal oxide / hydroxide includes but is not limited to calcium oxide, calcium hydroxide, magnesium oxide, magnesium hydroxide, and combinations thereof.

[0034] The slurry may be leached to form a leached slurry at a pressure ranging from 0 to 1540 psi, such as from a lower limit of any one of 0, 100, 250, 500 or 750 psi to an upper limit of any one of 800, 900, 1000, 1250, 1350 or 1450 psi, where any lower limit may be mathematically paired with any upper limit.

[0035] The slurry may also be heated to form a leached slurry at a temperature ranging from 100 to 500°C, such as from a lower limit of any one of 100, 125, 150, 200, 225, 250 or 275°C to any upper limit of any one of 300, 325, 350, 375, 400, 425, 450, 475 or 500°C, where any lower limit may be mathematically paired with any upper limit.

[0036] The slurry may also be leached for a time ranging from 1 second to 12 hours, such as from a lower limit of any one of 1 second, 1 minute, 30 minutes, 1 hour, 2 hours, 4 hours or 5 hours to an upper limit of any one of 6, 8, 9, 10, 11 or 12 hours, where any lower limit may be mathematically paired with any upper limit.

[0037] Leaching the slurry to form the leached slurry may also include filtering the leached slurry to separate the liquid filtrate from the solid residues and removing impurities from the liquid filtrate. The impurities include but are not limited to compounds including at least one of Ca, Mg, Al, or Fe. Removing the impurities may include techniques including at least one of selective precipitation, selective adsorption, or membrane-based methods. Filtering the leached slurry may also include washing the solid residue by re-dispersing solid particle in solution followed by liquid / solid separation. The washing step may include a multiple staged configuration, preferably in a counter-current arrangement.

[0038] As described above, the method includes processing the liquid filtrate to recover a lithium-rich organic solution. This processing step may include extracting lithium from the liquid filtrate with an extractant to produce an organic phase and a raffinate, removing the raffinate, scrubbing the organic phase with a scrubbing solution, and removing the scrubbing solution to provide the lithium-rich organic solution. The extracting and / or scrubbing steps may include multiple stages configured in a counter-current, concurrent or a combination of both configurations. The extractant used to extract the lithium may include di-(2-ethylhexyl) phosphoric acid, tri-n-butyl phosphate, tricaprylmethylammonium chloride, an ionic liquid, or a synergistic extractant system. A synergistic extractant system may be made through mixing one or more organic solventsto provide higher selectivity to certain elements. However, in a synergistic extractant system, solvents other than the extractant may be used. The scrubbing solution used may include water (or deionized water) and / or dilute acid. The dilute acid may be sulfuric acid with a concentration ranging from 1-200 g / L, such as from a lower limit of any of 1, 5, 10, 50 or 100 g / L to an upper limit of any of 50, 100, 110, 125, 150, 175 or 200 g / L, where any lower limit may be mathematically paired with any upper limit. .

[0039] The method described above also includes a step of processing the lithium rich organic solution to produce a battery grade lithium compound and sodium sulfate. According to one or more embodiments, processing the lithium rich organic solution may include stripping the lithium-rich organic solution with sulfuric acid, precipitating lithium carbonate, and refining the lithium carbonate. For stripping, a 1-200 g / L sulfuric acid solution may be used. Further, CO2 carbonation may be used to precipitate the lithium bicarbonate (LiHCCh), followed by decarbonation to produce the purified Li2CCh.

[0040] Processing the lithium rich organic solution may also include mixing the lithium- rich organic solution with carbon dioxide in an aqueous solution to form a suspension comprising lithium carbonate, separating the lithium carbonate from the suspension, and de-oiling the lithium carbonate. The lithium-rich organic solution may be mixed with water and carbon dioxide to form H2CO3. The H2CO3 may then be used to strip the lithium from the organic phase. For de-oiling, activated carbon or a deoiling resin may be used in a column and the organic solution may be passed through the column to de-oil the lithium carbonate. However, any suitable de-oiling method may be used.

[0041] Processing the lithium rich organic solution may also include mixing the lithium- rich organic solution with carbon dioxide in the presence of an aqueous solution, transferring lithium from the lithium-rich organic solution to the aqueous solution, deoiling the aqueous solution, and performing mechanical vapor recompression on the aqueous solution to obtain lithium carbonate. Any suitable de-oiling method may be used, such as using de-oil resin or activated carbon.

[0042] As a non-limiting example, lithium hydroxide may be recovered from the lithium- containing ceramics. In particular, the step of processing the lithium rich organic solution may include stripping the lithium-rich organic solution with a solution comprisinghydrogen peroxide to transfer lithium to the solution, de-oiling the solution, and performing mechanical vapor recompression on the solution to obtain the battery-grade lithium compound comprising lithium hydroxide. The hydrogen peroxide may be present in a concentration ranging from 1 to 20 wt%., such as from a lower limit of any of 1, 2, 5 or 10 wt% to an upper limit of any of 12, 15, 18 or 20 wt%, where any lower limit may be mathematically paired with any upper limit.

[0043] The following embodiments may be described in connection with the methods outlined above. Embodiments disclosed herein are directed to a method and apparatus for lithium recovery from silicate, aluminosilicate and other glass materials, such as petalite (LiAl(Si20s)2), lepidolite (K(Li,Al)3(Al,Si,Rb)4Oio(F,OH)2), spodumene (LiAl(SiO3)2), and lithium-bearing clay minerals. In addition to recovery of lithium compounds, the method disclosed herein also generates other value-added products. These additional products contribute to the overall economic and environmental viability of the process.

[0044] In the following discussion, ceramics refers herein to lithium aluminum silicate materials, silicate, aluminosilicate and other glass materials, petalite (LiAl(Si20s)2), lepidolite (K(Li,Al)3(Al,Si,Rb)4Oio(F,OH)2), spodumene (LiAl(SiO3)2), and lithium- bearing clay minerals, among others.

[0045] As will be discussed below, one or more aspects are directed to a method of recovering lithium and other valuable components from waste and scrap ceramics, including dissolving and leaching lithium and other valuable metal ions from feed solids into liquids, selectively extracting and recovering lithium and other value-added components, including AI2O3, SiCh, and Na2CC>3, from the liquids.

[0046] Referring to FIG. 1 an overall process disclosed herein for lithium and other value- added components recovery from silicates and aluminosilicates is shown. The embodiment shown in the FIG. 1 comprises three modules.

[0047] Module 1 - Metal Extraction from Solids into Liquids 102: In one or more embodiments, this module 102 provides means for extracting the valuable components from feed ceramics into liquids, which are further processed in subsequent modules. As will be discussed further below, several methods are developed to increase extractionefficiency. These methods include alkali roasting, salt roasting and leaching. Subsequently, the roasted material is fed to a sequential leaching process to obtain alkaline, neutral, and / or acidic leachates, depending on the roasting method and lixiviant used. According to another aspect, alternatively, high-pressure leaching may be used directly without roasting. Those having ordinary skills in the art will appreciate that the methods of extracting the valuable components from feed ceramics into liquids are not limited to the above mentioned.

[0048] Module 2 - Lithium Extraction from Liquids 104: In one or more embodiments, the purpose of this module is to selectively extract lithium from the leachates obtained in Module 1 by various methods, including solvent extractions, selective adsorptions with resins, precipitation, purification. Two different solvent extraction systems are disclosed to process the alkaline as well as the neutral and acidic leachates, respectively. Those having ordinary skill in the art will appreciate that the two solvent extraction systems disclosed herein are meant only to be examples and may include any methods known in the art.

[0049] Module 3 - Other Valuable Components Extraction from Liquids 106: During the alkali roasting and high-pressure alkali leaching processes in Module 1, certain valuable components such as silicon and aluminum are expected to be dissolved due to the strongly alkaline environment, and / or efficient leaching methods developed herein. The alkaline leachate after solvent extraction in Module 2 will be processed in this module to recovery value-added components, including AI2O3, SiCh, and Na2COs. Staged precipitation using carbon dioxide and ordinary acids as the precipitant is developed to obtain crude AI2O3 and SiC>2 products, which is further purified into high-purity compounds. The remaining solution is subjected to mechanical vapor recompression to generate clean water and recover Na2CC>3.

[0050] Referring to FIG. 2, a process flow diagram of a method for recovering lithium and other valuable components from lithium aluminum silicate (LAS) ceramics in accordance with one or more embodiments is shown. In the embodiment shown in the figure, silicate, aluminosilicate and other ceramics feed materials are comminuted 102 by crushing, milling, grinding, sieving to obtain a product, referred herein as a ceramics powdermaterial with particle sizes of smaller than, for example, 75 to 250 microns, by passing through a mesh screen of a 10 to 400 mesh. Those having ordinary skill in the art will appreciate that any method, not limited to the above mentioned, may be used to comminute feed ceramics into particles, and any method may be used to screen the crushed particles to a certain size.

[0051] A wide array of commercially available crushers and mills, such as jaw crushers, roller crushers, hammer mills, and attrition mills, can be used in the comminution process. However, it is noteworthy to point out that some feed ceramics materials exhibit exceptionally high levels of hardness. Consequently, there may be a requirement to redesign the crushing and grinding media used in conventional crushers and mills with materials that offer greater hardness.

[0052] A leaching process is then performed on the comminuted ceramics powder to dissolve lithium and other valuable metals. In the embodiment shown in FIG. 2, several roasting and leaching methods are disclosed herein to obtain improved extraction efficiency of lithium and other valuable components. These methods, which will be discussed further below, include alkali roasting and leaching, salt roasting and leaching, high-pressure leaching. Alkaline, neutral, or acidic leachates may be obtained, depending on the roasting method and lixiviant used.

[0053] In one aspect of embodiments, the comminuted ceramics material 202 may go through a pre-treatment process. The pre-treatment process may comprise of coating, granulation, and alkali roasting 203. In the roasting process, alkali is added. This method disclosed herein is based on the reaction of feed ceramics materials with alkalis at temperatures higher than the melting temperature of the added alkali. Alkalis, such as NaOH, generally have relatively low melting points (e.g., 318 °C of NaOH); thus, when operating at temperatures exceeding the alkali’s melting points, the interaction between the feed materials and the alkalis becomes a solid / liquid reaction, as opposed to a solid / solid reaction. A solid / liquid reaction is more effective than a solid / solid reaction. Additionally, the alkalis created a highly alkaline environment capable of destroying the structure of silicates and aluminosilicate. Simultaneously, alkali metal ions, such assodium ions, can exchange lithium from the structure of the feed materials. These factors collectively contribute to improved leachability of lithium from the feed materials.

[0054] Pretreatment and leaching 204: in one aspect of embodiments, the comminuted feed material may be mixed with alkalis to form a uniform mixture during the coating and granulation step, which will subsequentially be fed to roasting. The benefits of adding this coating and granulation process are that the alkalis can be uniformly distributed and coated onto the feed particles, resulting in improved roasting performance while reducing alkali consumption. Besides conventional powder-to-powder mixing approaches, the embodiments disclosed herein includes an innovative powder-to-liquid mixing method. In this method, a concentrated alkaline solution is first prepared by dissolving the alkali in water, and the comminuted feed particles are mixed with the solution and are uniformly coated with the alkali. Afterwards, uniformly mixed granules are prepared from the mixture by various methods, such as spray drying, fluidized bed granulation, freeze granulation, and stream granulation. The granules are then to be fed to a roasting step to be discussed next.

[0055] In one or more embodiments, the pretreatment may include a roasting step. During this step, the granules may be roasted at relatively high temperatures (e.g., 500 °C) to facilitate the reaction between the feed material and the alkali. The reaction can occur in different types of roasters, such as kiln furnaces, muffle furnaces, tube furnaces, rotary furnaces, belt furnaces, among others. After roasting under optimal conditions determined by parametric studies of, for example, temperature (200-600 °C), roasting duration (0.5 - 24 hours), alkali / feed ratio (50%-300%, among others, the roasted material is collected and transferred to the sequential leaching step. The roasting reaction can occur in different types of roasters, such as kiln furnaces, muffle furnaces, tube furnaces, rotary furnaces, and belt furnaces, among others.

[0056] Further, in one or more embodiments, sequential water and acid leaching may be performed after roasting. During this step, the roasted material undergoes a sequential leaching process by reacting with various lixiviants. The roasted material is first leached with water to dissolve readily leachable components and residue alkali, leading to an alkaline leachate containing lithium and other components, such as silicon, aluminum,and alkali metal ions introduced during the roasting step. Subsequently, the solid residue is leached again under weakly acidic pH to achieve increased recovery of lithium and other valuable components. The alkaline and acidic leachates can either be processed separately or combined and processed jointly in subsequent solvent extraction step. A significant advantage of the sequential leaching process is that a cheap lixiviant, water, is used to extract most of the lithium and other valuable components from the roasted material. In the meantime, increased extraction efficiencies are achieved by acid leaching. Those having ordinary skill in the art will appreciate that, in addition to the two-step leaching with water and acid, the sequential leaching process may be modified by using other types of lixiviants known in the art (e.g., salt solutions) and / or the same lixiviant of different concentrations (e.g., solutions of the same acid but with varying acidities).

[0057] In one or more embodiments, solid / liquid separation may be conducted after leaching to separate liquids from solids. Any commercially available solid / liquid separation method, such as filter press, may be used for this purpose. After solid / liquid separation, the liquids (i.e., filtrates), which contain dissolved and leached lithium and other valuable metals, are collected and will be further processed as discussed further below. The resulting filter cake may be rinsed directly inside the filter press and / or rinsed by re-dispersing in water followed by filtration again. The rinsing solutions may be mixed with the filtrates or reused in the other parts of the overall process.

[0058] In another aspect of embodiments, instead of alkalis, the leachability of lithium from silicates and aluminosilicates may also be improved by roasting with salts. At temperatures above the melting point of salts, alkali metal ions can diffuse into the structure of the materials, thereby enhancing the leachability of lithium. Since the melting temperature of salts is normally higher than that of alkalis, salt roasting may require a higher temperature than alkali roasting. Similar to alkali roasting, sequential water and acid leaching may be performed after roasting to achieve maximum leaching efficiency and reduce leaching costs. Nonetheless, the leachate generated from the water leaching step is neutral instead of highly alkaline.

[0059] One aspect is the pretreatment method of coating and granulation prior to roasting. The benefits of coating and granulation of ceramic particles in an alkalis or salt solutionare that the ceramics particles are uniformly coated with alkalis or salt, and that powerliquid mixing is more effective than power-powder mixing, resulting in reduced consumption in alkalis or salt, improved roasting performance and improved lithium and other valuable component recovery efficiency from 70% (prior art) to nearly 100%.

[0060] Another aspect is to reduce roasting temperature required to destroy the structure of lithium-containing silicates and aluminosilicates from 900-1000 °C (prior art) to 500 °C, due to the addition of alkalis and / or salts. The benefits of such roasting temperature reduction are significant in terms of manufacturing process and energy consumption.

[0061] In a third aspect of embodiments, leaching of the comminuted ceramics material 202 with an alkaline solution may be conducted directly without pretreatment as described above at high temperature in a high-pressure reactor. In high-pressure leaching 204, a slurry is prepared by mixing the comminuted ceramics feed with a lixiviant, and the slurry is then introduced into a high-pressure reactor. Since the reactor is closed, the pressure within it gradually increases with elevations in temperature. This combination of pressure and temperature promotes the leaching of lithium and other components from the feed materials by increasing solubility, enhancing mass transfer, improving reaction kinetics, and decreasing particle size. Excellent extraction efficiency can be achieved using either acidic or alkaline lixiviants. However, the resulting acidic and alkaline leachates need to be processed using different methods in Module 2 - Lithium Extraction from Liquids 104.

[0062] The steps using high-pressure leaching to enhance the extraction of lithium and other valuable components from silicates and aluminosilicates are: the comminuted feed material is mixed with a lixiviant, and the resulting slurry is then transferred to a high- pressure reactor. After reacting for a certain period of time at a certain pressure and temperature, the slurry is transferred from the reactor to a filter press for solid / liquid separation. As those having ordinary skill in the art will appreciate that the required roasting time may depend on roasting temperature and pressure. The resulting filter cake is rinsed directly inside the filter press and / or rinsed by re-dispersing in water followed by re-filtration. After solid / liquid separation, the liquid (i.e., filtrate) is collected and sentto the other modules. The rinsing solution may be mixed with the filtrate or reused in the other parts of the overall process.

[0063] As those having ordinary skill in the art will appreciate, alkaline solution, calcium oxide or calcium hydroxide may be added in the high-pressure alkaline leaching step to increase leaching efficiency and lithium recovery yield, depending on feed chemical compositions. As an example, when the feed material is basic and contains a sufficient amount of alkali metals (e.g., > 5 wt.%), adding alkali may not be required in the high- pressure leaching step. Hydrogarnet can be formed with the addition of calcium oxide or calcium hydroxide.

[0064] After leaching of lithium and other valuable components from the comminuted ceramics material 202, the leaching slurry 204 may then be subjected to a solid / liquid separation step, such as filtration, to separate the residue solid (i.e. filter cake) from liquid filtrate or leaching solution. The filtrate is further process to selectively extract lithium and other valuable components, for example, by selective adsorption with resins or solvent extraction 206 with efficient extractants, wherein the solvent phase containing lithium and the raffinate phase containing other valuable components.

[0065] In one aspect of embodiments, solvent extraction 206 may be preferred because of its high processing capacity. Two solvent extraction systems are disclosed herein to process leachates of different pH, as will be discussed further below. The alkaline leachate will be processed using an extractant that is suitable for lithium extraction under alkaline conditions. The neutral and acidic leachates will be processed using an extractant that is suitable for lithium extraction under neutral and acidic conditions.

[0066] In another aspect of embodiments, it should be pointed out that although solvent extraction is used herein to separate lithium-rich solution from raffinate, other methods such as selective adsorption with resins may be used also. Selective adsorption may also be chosen due to its capability to concentrate lithium. The extraction of lithium from liquids using resins may be performed in two different stages: adsorption and desorption. In the adsorption step, lithium is extracted from the liquids to the resins, while in the desorption step, the resins loaded with lithium will be washed with a solution (e.g., water, water with low concentrations of lithium, etc.).

[0067] After obtaining lithium-rich solution 208, lithium carbonate may be produced from the solution by carbonate precipitation, wherein carbonates, such as sodium carbonate, may be used as precipitants of lithium with the generation of a crude lithium carbonate 212. The crude lithium carbonate product 212 may be processed further by reacting with CO2. In the presence of CO2, lithium carbonate precipitate will be dissolved in the form of lithium bicarbonate, while the other components in the product will remain undissolved. After solid / liquid separation, high-purity battery grade lithium carbonate 214 can be produced from the lithium bicarbonate solution by removing CO2 from the solution by, for example, heating, or depressurization.

[0068] After solvent extraction under alkaline conditions, the resulting raffinate 210 may be alkaline and contain other valuable components, such as silicon, aluminum, and alkali metal ions. Based on the speciation diagram of aluminum and silicon shown in FIG. 3, these two elements gradually transform from soluble to insoluble species with decreases in the solution pH. In addition, the pH values corresponding to the initiation of the precipitation of these two elements are different, suggesting that aluminum-rich and silicon-rich products can be obtained by staged carbonations and collecting the precipitates formed at different pH ranges.

[0069] In one aspect of embodiments shown in FIG. 2 regarding to the staged carbonation process 216, instead of adding acid, carbon dioxide may be used to reduce the pH of the solution. When carbon dioxide is sparged into the solution, carbon dioxide will react with water to form carbonic acid, which will dissociate into hydrogen, carbonate, and bicarbonate ions. The hydrogen ions will react with hydroxyl groups in the solution, causing reductions in the pH, while the carbonate and bicarbonate ions will combine with alkali metal ions.

[0070] Based on these mechanisms, a staged carbonation method was developed by the inventors. During the staged carbonation process, carbon dioxide is introduced into the alkaline raffinate 210, and the solution pH is continuously monitored. Once a certain pH value is reached, SiO2 or AI2O3 will precipitate out and may be collected from the solution by solid / liquid separation. Subsequently, this procedure is repeated to obtain AI2O3 or SiO2 precipitates formed at a lower pH. The recovered AI2O3 and SiO2 compounds maybe further purified into high-grade compounds for beneficial uses, for example, by washing with a weakly acidic solution to remove impurities.

[0071] Further, in one or more embodiments, the solution after SiCh and AI2O3 recovery from the by staged carbonation described above may contain a large amount of carbonate and / or bicarbonate species due to the dissolution of carbon dioxide. Evaporation such as mechanical vapor recompression (MVR) may be used to evaporate water from the solution after staged carbonation, leaving sodium carbonate 218 as a value-added byproduct, which may be sold as a product or reused as a reactant in the alkali roasting and / or carbonate precipitation steps. As those having ordinary skill in the art will appreciate, an additional step may be added between staged carbonation and evaporation to remove impurities and enhance the purity of the sodium carbonate. Various separation and purification methods, such as solvent extraction with efficient extractants and selective adsorption with resins, may be adopted in this step to achieve the objective.

[0072] In another aspect of embodiments as shown in FIG. 2, instead of using carbon dioxide to lower the pH of the raffinate solution, ordinary acids may be used to lower the pH of the raffinate solution during the carbonation stages 216 to obtain AI2O3 or SiCh precipitates. The acids may be hydrochloric acid, nitric acid, sulfuric acid, and organic acids. Those with ordinary skill in the art will appreciate that localized hyperacidity may arise when strong acids are used, which may impair extraction performance. To avoid this issue, the acids need to be added slowly to the raffinate while ensuring thorough mixing for uniform distribution.

[0073] In a third aspect of embodiments as shown in FIG. 2 regarding to the staged carbonation process 216, instead of two staged carbonations, the carbonation and precipitation may be performed in one stage. In this case, a mixed preconcentrate of Al and Si may be obtained using acid to lower the pH of the raffinate solution. The preconcentrate of the AI2O3 and SiCh mix may be washed in a solution of neutral and weakly alkaline pH (e.g., pH 9.0) to obtain a purified product of AI2O3 and SiCh mix. Moreover, the preconcentrate may also be washed in a solution of acidic pH (pH<3) to obtain high-purity SiCh, leading to a washing solution rich in Al and alkali metal ions.The washing solution can be further processed using appropriate methods, such as solvent extraction and selective precipitation, to obtain high-purity Al products.

[0074] As used herein, “contaminants” or “impurities” refers to undesired materials in the final products. Contaminants and impurities include, but are not limited to aluminum, copper, calcium, magnesium, titanium, silicon, zinc, sulfur, and fluoride.

[0075] As used herein, “lithium compound” refers to a chemical compound that includes lithium atoms bonded with other elements, such as lithium carbonate and lithium hydroxide.

[0076] As used herein, “silicate material” or “silicate” refers to a material containing silicate groups and / or silicon atoms, such as glass-ceramics, clays, spodumene.

[0077] As used herein, “battery-grade” refers to the purity and other specifications of the products that meet the standards of being used for battery manufacturing.

[0078] As used herein, “solvent extraction” refers to metal separation and concentration by mixing two immiscible phases, typically an aqueous phase and an organic phase. During the mixing process, metal ions transfer from one phase to another.

[0079] As used herein, “aqueous phase” refers to the phase with higher density during the solvent extraction process. It is used interchangeably with “aqueous solution” and “solution” in this disclosure.

[0080] As used herein, “organic phase” refers to the phase with lower density during the solvent extraction process.

[0081] As used herein, “loaded organic phase” refers to an organic phase containing metal ions, and “lithium-loaded organic phase” refers to an organic phase containing lithium ions along with or without other metal ions.

[0082] As used herein, “extractant” refers to the active organic compounds present in the organic phase that can selectively interact with selected types of metal ions.

[0083] As used herein, “diluent” refers to the organic chemicals used to dissolve the extractant. 1

[0084] As used herein, “scrubbing” refers to the removal of undesired constituents from a loaded organic phase by mixing with an appropriate aqueous solution.

[0085] As used herein, “stripping” refers to the removal of target valuables from the organic phase.

[0086] As used herein, “oil” or “organic compounds” refers to the chemicals present in the organic phase.

[0087] As used herein, “relatively pure water” refers to water with low concentrations of undesired impurities.

[0088] As used herein, “suspension” refers to a mixture of a liquid with solid particles dispersed within it.

[0089] The embodiments disclosed herein include a process for the production of batterygrade lithium compounds from any silicate solid material containing lithium. The process includes slurrying to form a well-mixed slurry, high-pressure leaching to dissolve lithium, solid / liquid separation to separate the solid from the solution, impurity removal to eliminate impurities from the solution, solvent extraction and scrubbing to obtain an organic phase loaded with lithium from the solution, battery-grade lithium compound production to produce battery-grade lithium products from the organic phase, washing after the solid / liquid separation to recover lithium entrapped within the solid, and thermal drying to obtain a solid product that can be used for other beneficial purposes.

[0090] Referring to FIG. 1, a process flow diagram in accordance with embodiments disclosed herein is shown. This process may be used to produce battery-grade lithium compounds (e.g., carbonate, hydroxide) from lithium-containing silicate materials, including but not limited to glass-ceramics and silicate minerals.

[0091] Embodiments disclosed herein are directed to a process based on high-pressure leaching to extract and purify lithium from silicate materials. In one aspect, the high- pressure leaching process employs a strong base like sodium hydroxide to destroy the structure of lithium-containing silicate materials, leading to the release of lithium into the leaching solution and the transfer of alkali metals introduced with the strong base to the solid residue. Concurrently, the presence of an alkaline earth oxide / hydroxide in thereaction system causes the solid residue to convert into a material that contains alkaline earth metals, aluminum, and silicon, while releasing the alkali metals into the leaching solution. Consequently, during the high-pressure leaching process, lithium is dissolved from the silicate materials, and the strong base is regenerated, consuming only the alkaline earth metal oxide / hydroxide, which is cost-effective. Furthermore, the process achieves zero waste generation and one hundred percent water recycling through the deliberate design of the unit operations involved.

[0092] As shown in FIG. 6, feed 600, water 602, base 604, and alkaline earth metal oxide / hydroxide 606 are directed to slurrying step 608 to form a thoroughly mixed slurry. The feed may be comminuted first through crushing and / or grinding to an appropriate particle size, such as below 50 mesh, preferred particle size range is below 100 mesh. The water may partially or completely come from the downstream solvent extraction and washing steps. The base needs to have the capability to break down the structure of the feed. The alkaline earth metal oxide / hydroxide includes, but is not limited to, calcium oxide, calcium hydroxide, magnesium oxide, and magnesium hydroxide. Those having ordinary skill in the art will appreciate that the feed may originate from different sources, such as glass-ceramics, silicate minerals, industrial silicate wastes, and / or lithium containing natural minerals, such as spodumene, lepidolite.

[0093] The resulting slurry is directed to high-pressure leaching step 610 to dissolve lithium from the feed into the leaching solution. In one or more embodiments, the slurry mixture can be heated to a temperature of about 50 °C to about 500 °C.

[0094] The target pressure during the reaction can be greater than 0 psi. In some embodiments the target pressure can range from about 0 psi to about 1450 psi. The target reaction duration can be greater than 1 second. In some embodiments the target reaction duration can range from about 1 second to about 12 hours.

[0095] The slurry mixture after high-pressure leaching is directed to solid / liquid separation 612 to separate the solid from the liquid. Any solid / liquid separation methods, such as filter press, vacuum filter, or belt filter, may be used for this step. The liquid after the separation may be referred to as filtrate, leachate, or solution in the following discussion and the claims. The solid after the separation may be referred to as filter cake, leachingresidual, solid residue, or simply solid, as discussed in the following discussion and in the claims. After solid / liquid separation, a lithium-containing solution 614 and a solid residue 616 that still contains some lithium are obtained, which are further processed as discussed next.

[0096] The lithium-containing solution 614 is directed to impurity removal step 618 to eliminate impurities that will interfere with the downstream steps. In one or more embodiments, depending on the chemistry used in the downstream step, the impurities that may be eliminated include but are not limited to calcium, magnesium, aluminum, and iron. In some embodiments, the impurities may be removed via a single method or a combination of different methods, such as selective precipitation, selective adsorption, and membrane-based methods.

[0097] The lithium-containing solution after impurity removal is directed to solvent extraction 620 to concentrate and purify lithium. During the solvent extraction process, the solution is mixed with an organic phase prepared by mixing an extractant into a diluent.

[0098] In one or more embodiments, the diluent serves as a solvent for the extractant and may include, but is not limited to, kerosene, n-hexane, and heptane. The extractant exhibits a higher affinity for lithium ions compared to contaminants. Those having ordinary skill in the art will appreciate that different types of extractant are available for the extraction of lithium, which can be classified into acidic extractants (e.g., di-(2- ethylhexyl) phosphoric acid (D2EHPA)), neutral extractants (e.g., tri-n-butyl phosphate (TBP)), amines and quaternary ammonium compounds (e.g., tri caprylmethylammonium chloride (Aliquat 336)), ionic liquids, and synergistic solvent extraction systems. Those having ordinary skill in the art will also appreciate that in addition to the diluent and extractant, some other chemicals, such as phase modifiers, stabilizers, surfactants, and anti-foaming agents, may be added to the organic phase to enhance its performance of lithium extraction.

[0099] In one or more embodiments, the solution and the organic phase are mixed in a reactor to facilitate the transfer of lithium ions from the solution into the organic phase. To achieve the desired purity and extraction efficiency, the extraction process mayinvolve multiple extraction stages, and the extraction flowsheet may be configured in various arrangements, such as counter-current, co-current, or a combination of both. Those having ordinary skill in the art will appreciate that different types of reactors, such as mixer-settlers and centrifugal extractors, can be utilized for this step. Following mixing, the reactors can continuously separate the two phases based on their immiscibility and density differences.

[0100] After solvent extraction, an organic phase loaded with lithium and a raffinate 622 depleted in lithium are obtained. The raffinate may be used for the washing step 624 of the solid residue and / or the as the source of water 602 for the slurring step 608. Some contaminants may be co-extracted into the organic phase during solvent extraction. Therefore, the organic phase loaded with lithium may be directed to scrubbing step 626 to eliminate the impurities. Similar to the solvent extraction step, the organic phase is mixed with an aqueous solution in the scrubbing step. In one or more embodiments, the aqueous solution may be the condensed water generated from downstream steps mixed with and / or without dilute acid. In some embodiments, to achieve the desired impurity removal efficiency, the scrubbing process may involve multiple stages, and the scrubbing flowsheet may be configured in various arrangements, such as counter-current, cocurrent, or a combination of both. Those having ordinary skill in the art will appreciate that different types of reactors, such as mixer-settlers and centrifugal extractors, can be utilized for this step. Following mixing, the reactors can continuously separate the two phases based on their immiscibility and density differences.

[0101] After scrubbing, a scrubbing solution 628 containing primarily impurities and an organic phase 630 loaded with relatively pure lithium are obtained. During the scrubbing process, some lithium may be co-scrubbed with the impurities from the organic phase to the aqueous solution. Consequently, the scrubbing solution may be re-directed to the solvent extraction step 620. In this way, the lithium in the scrubbing solution can be reextracted and recovered instead of being lost. The organic phase 630 may be directed to battery-grade lithium compound production step 632 to generate the desired lithium product.

[0102] Depending on the target type of the lithium compound and the chemistry of the organic phase, different methods may be applied in the battery-grade lithium compound production step. In one or more embodiments, the organic phase loaded with lithium may be mixed with a dilute sulfuric acid solution to transfer lithium from the organic phase to the solution. After phase separation, the solution containing lithium may react with sodium carbonate, resulting in the formation of lithium carbonate precipitate. The precipitate may be collected via solid / liquid separation, while the residual solution may be evaporated to precipitate sodium sulfate. Depending on the purity of the precipitate, it may be subjected to a refinement step to meet the battery-grade quality.

[0103] In one or more embodiments, the organic phase loaded with lithium may react with carbon dioxide in the presence of an aqueous solution (e.g., deionized water). Lithium carbonate precipitates out from the organic phase when the volumetric ratio of the aqueous solution to the organic phase is relatively low. After that, the suspension is subjected to solid / liquid separation to separate the solid from the liquid. The solid may be directed to a de-oiling step to remove any organic compounds entrapped within the solid. Finally, a battery-grade lithium carbonate is obtained.

[0104] In one or more embodiments, the organic phase loaded with lithium may react with carbon dioxide in the presence of an aqueous solution (e.g., deionized water). Lithium is transferred from the organic phase to the aqueous solution in the form of dissolved lithium bicarbonate when the volumetric ratio of the aqueous solution to the organic phase is relatively high. After phase separation, the aqueous solution containing lithium bicarbonate is subjected to a de-oiling step to remove any potential organic compounds. Subsequently, the solution is directed to mechanical vapor recompression (MVR) to obtain battery-grade lithium carbonate product.

[0105] In one or more embodiments, the organic phase loaded with lithium may react with a hydrogen peroxide solution to transfer lithium from the organic phase to the solution. After phase separation, the solution is then subjected to de-oiling to remove any organic compounds. Subsequently, the solution is directed to mechanical vapor recompression (MVR) and impurity removal to obtain a lithium hydroxide product, which may be further processed to meet the battery-grade quality.

[0106] Battery-grade lithium carbonate or hydroxide 634 may be produced from the battery-grade lithium compound production step 632. In addition, as noticed from above descriptions, evaporation may be used for the production step, along with the generation of condensed water 636. The water is relatively pure and may be used for the scrubbing step 626 and / or the washing step 624.

[0107] The solid residue 616 obtained from the solid / liquid separation step 612 may contain some lithium. Consequently, the solid residue may be washed using the water generated from solvent extraction 120 and / or the downstream thermal drying step. In one or more embodiments, the solid residue may be slurried by mixing with water to ensure sufficient dispersion of the solid particles in water. The resulting slurry may be subjected to solid / liquid separation to separate the solid from the liquid. In some embodiments, washing may be carried in multiple stages that may be configured into different arrangements, such as counter-current, co-current, or a combination of both.

[0108] After washing, the solution 638 may be directed to slurrying 608 for being used as a source of water. The washed solid residue 640 may be directed to thermal drying step 642 to obtain a dried solid residue 644. The solid residue may contain aluminum, calcium, and silicon and thus can be beneficially used for other purposes, such as construction materials. The condensed water 646 collected during the thermal drying process may be reused for washing and / or other steps of the process.

[0109] EXAMPLES

[0110] Example 1 : Laboratory-scale experimental tests were performed on two glass / ceramics samples, which contain 1.45% and 5.5% of lithium, respectively. The materials were ground to below 100 mesh using a hammer mill. The ground products were mixed with sodium hydroxide with a mass ratio of 1 :2. The mixtures were roasted in a furnace at 500 °C for 4 hours under ambient pressure. After that, the roasting products were mixed with water at a solid-to-liquid ratio of 1 :20. The resulting slurries were continuously stirred for 1 hour. After that, the slurry was filtered using a vacuum filter. The residual solid on the filter paper was re-dissolved in an acidic solution with the pH being fixed at 4.0 by intermittently dosing concentrated sulfuric acid. After filtration using a vacuum filter, the filtrate (pH 4.0) was mixed with the water leaching solution(pH 14.0), resulting in a mixed solution with a pH of approximately 13.0. Under these conditions, approximately 75-80% of Li is leached in the water leaching step, while approximately 20-25% of Li is leached in the acid leaching step, resulting in nearly 100% leaching efficiency of Li from ceramics.

[0111] The mixed solution is directly fed to solvent extraction without any pH adjustment. As Table 1 shows, nearly all the lithium was extracted to the lithium-rich solution, while the majority of Al was reported in the raffinate solution. Industrial grade carbon dioxide was sparged into the raffinate solution, and the pH of the solution was continuously monitored. When the pH was reduced to 12.0, the precipitate formed in the solution was collected by filtration. The pH of the filtrate was further reduced with the continuous introduction of carbon dioxide into the solution. When the pH was reduced to 10.0, the newly formed precipitate was also collected by filtration. Elemental composition analysis shows that the second precipitate contain > >99.5% of SiCh (FIG. 4). After staged carbonation, the remaining solution is processed via MVR to obtain sodium carbonate. SEM-EDS analysis was also performed on this product, whereas carbon was excluded when conducting EDS analysis since carbon tape was used to prepare the SEM specimen. As FIG. 5 shows, only Na and O were detected from the analysis, suggesting that the product is of high purity.

[0112] Table 1: Elemental concentrations in the raffinate and lithium-rich solution obtained from solvent extraction (the feed contains 5.5% lithium)

[0113] Example 2: The disclosed process was tested on a naturally occurring, lithium- containing mineral. The mineral was first crushed to a top particle size of 1 mm using a hammer crusher. The resulting particles were mixed with a 5 mol / L sodium hydroxide solution. The mixture was then spray dried at 150 °C, resulting in large granules. The granules were then roasted in a tube furnace at 500 °C for 2 hours. The roasted material was mixed with water at a solid / liquid ratio of 1 / 10. The mixture was stirred at 70 °C for 30 min. Subsequently, the mixture was filtered, and the filter cake was mixed with anacidic solution at a solid / liquid ration of 1 / 10. The mixture was stirred at 60 °C for 2 hours with the pH maintained at 4.0. Afterwards, the mixture was filtered, and the filter cake was rinsed. The resulting filtrates and rinsing solutions were mixed, leading to a solution has a pH of around 13.5. The mixed solution was then processed through solvent extraction using an extractant suitable for lithium extraction under alkaline conditions, leading to a solution rich in lithium and a raffinate rich in aluminum and silicon. The lithium-rich solution was mixed with a sodium carbonate solution of 3.5 mol / L at a volumetric ratio of 1 / 1. The resulting precipitate was filtered and washed with deionized water. The filter cake was re-dispersed in deionized water at a solid / liquid ratio of 1:5. CO2 was continuously sparged into the resulting slurry for around 3 hours. Subsequently, the slurry was filtered, and the filter cake was rinsed with CCh-saturated water. The filtrate and the rinsing water were mixed, and the mixture was heated at 90 °C for 12 hours. The resulting precipitates were collected by filtration followed by washing with deionized water. Finally, the precipitates were thermally dried at 60 °C. Elemental analysis showed that the precipitates were lithium carbonate with a purity of 99.85%.

[0114] The raffinate obtained from solvent extraction was processed to recover aluminum and silicon. CO2 was continuously sparged into the raffinate for around 30 mins. Subsequently, the raffinate was filtered, and the filter cake was collected. A portion of the filter cake was washed with deionized water until the pH of the washing solution stabilized at around 9. Finally, the filter cake was thermally dried. Elemental analysis showed that the filter cake was an aluminum and silicon oxide mix with a purity of 99.95%. The remaining portion of the filter cake was washed with a weakly acidic solution until the pH of the washing solution stabilized at around 2.8. Finally, the filter cake was thermally dried. Elemental analysis showed that the filter cake was a silicon oxide product with a purity of 99.98%. The washing solution obtained from the last step was fed to cation-exchange columns. After multiple stages of adsorption and desorption, a solution rich in relatively pure aluminum (>99%) was obtained. An aluminum hydroxide product of 99.5% purity was obtained from the solution through MVR.

[0115] Example 3: The disclosed process was tested on a naturally occurring, lithium- containing mineral. The mineral was first crushed to a top particle size of 1 mm using ahammer crusher. The resulting particles were mixed with a 5 mol / L sodium hydroxide solution. The mixture was then dried at 200 °C in a tumbler, resulting in large granules. The granules were roasted in a muffle furnace at 450 °C for 2 hours. The roasted material is then mixed with water at a solid / liquid ratio of 1 / 3. The mixture was stirred at room temperature for 30 min. Subsequently, the mixture was filtered, and the filter cake was mixed with an acidic solution at a solid / liquid ration of 1 / 5. The mixture was stirred at 80 °C for 1 hour with the pH maintained at 5.0. Afterwards, the mixture was filtered, and the filter cake was rinsed. The resulting filtrates and rinsing solutions were mixed, leading to a solution has a pH of around 13.0. The mixed solution was then processed through solvent extraction using an extractant suitable for lithium extraction under alkaline conditions, leading to a solution rich in lithium and a raffinate rich in aluminum and silicon. The lithium-rich solution was mixed with a sodium carbonate solution of 3.5 mol / L at a volumetric ratio of 1 / 1. The resulting precipitate was filtered and washed with deionized water. The filter cake was re-dispersed in deionized water at a solid / liquid ratio of 1:5. The filter was mixed with lime mix to form a uniform slurry. The slurry was continuously mixed at 100 °C for 1 hour. Deionized water was frequently added during the process to maintain the slurry state. Subsequently, the slurry was filtered, and the filter cake was rinsed with deionized water. The filtrate and rinsing water were mixed and processed in MVR, resulting a lithium hydroxide monohydrate product. The product was re-dissolved in deionized water. The undissolved solids were removed by filtration, and then, the filtrate was re-processed in MVR, resulting in a pure lithium hydroxide monohydrate product. The product was treated in a muffle furnace at around 150 °C, leading to a final lithium hydroxide product. Elemental analysis showed that the product has a purity of 99.67%.

[0116] The raffinate obtained in the solvent extraction step was processed to recover aluminum and silicon. CO2 was continuously sparged into the raffinate until the pH dropped to around 11. The resulting precipitates were collected by filtration and washed with deionize water. The filtrate and washing solution were mixed, and CO2 was sparged into the mixed solution until the pH dropped to around 7.0. The resulting precipitates were collected by filtration and washed with deionized water. The filtrate was processed in MVR, leading to a solid product. Elemental analysis and SEM-EDS analysis showedthat the product was sodium carbonate with 99.9% purity. The precipitates obtained at pH 7.0 were dried. Elemental analysis showed that the precipitates were silicon oxide with a purity of 99.85%. The precipitates obtained at pH 11 were also dried and measured to be 99.63% pure aluminum oxide.

[0117] Example 4: The disclosed process was tested on a lithium-containing aluminosilicate glass. Elemental analysis showed that the material contained around 5% of Li. The mineral was first crushed to a top particle size of 74 pm (passing through a 200-mesh screen) using a jaw crusher and a hammer mill. The resulting particles were mixed with a 7 mol / L sodium hydroxide solution. The mixture was then spray dried at 150 °C, resulting in large granules. The granules were then roasted in a tube furnace at 500 °C for 2 hours. The roasted material was mixed with water at a solid / liquid ratio of 1 / 10. The mixture was stirred at 70 °C for 30 min. Subsequently, the mixture was filtered, and the filter cake was mixed with an acidic solution at a solid / liquid ratio of 1 / 10. The mixture was stirred at 60 °C for 2 hours with the pH maintained at 4.0. Afterwards, the mixture was filtered, and the filter cake was rinsed. The resulting filtrates and rinsing solutions were mixed, leading to a solution has a pH of around 13.9. The mixed solution was then processed through solvent extraction using an extractant suitable for lithium extraction under alkaline conditions, leading to a solution rich in lithium and a raffinate rich in aluminum and silicon. The lithium-rich solution was mixed with a sodium carbonate solution of 3.5 mol / L at a volumetric ratio of 1 / 2. The resulting precipitate was filtered and washed with deionized water. The filter cake was re-dispersed in deionized water at a solid / liquid ratio of 1 :5. CO2 was continuously sparged into the resulting slurry for around 3 hours. Subsequently, the slurry was filtered, and the filter cake was rinsed with CCh-saturated water. The filtrate and the rinsing water were mixed, and the mixture was heated at 90 °C for 12 hours. The resulting precipitates were collected by filtration followed by washing with deionized water. Finally, the precipitates were thermally dried at 60 °C. Elemental analysis showed that the precipitates were lithium carbonate with a purity of 99.78%.

[0118] The raffinate obtained from solvent extraction was processed to recover aluminum and silicon. CO2 was continuously sparged into the raffinate for around 50 mins.Subsequently, the raffinate was filtered, and the filter cake was collected. A portion of the filter cake was washed with deionized water until the pH of the washing solution stabilized at around 9. Finally, the filter cake was thermally dried. Elemental analysis showed that the filter cake was an aluminum and silicon oxide mix with a purity of 99.91%. The remaining portion of the filter cake was washed with a weakly acidic solution until the pH of the washing solution stabilized at around 2.8. Finally, the filter cake was thermally dried. Elemental analysis showed that the filter cake was a silicon oxide product with a purity of 99.94%. The washing solution obtained from the last step was fed to cation-exchange columns. After multiple stages of adsorption and desorption, a solution rich with relatively pure aluminum (>99%) was obtained. An aluminum hydroxide product of 99.3% purity was obtained from the solution through MVR.

[0119] Example 5: The disclosed process was tested on a lithium-containing aluminosilicate glass. Elemental analysis showed that the material contained around 5% of Li. The mineral was first crushed to a top particle size of 74 pm (passing through a 200-mesh screen) using a jaw crusher and a hammer mill. The resulting particles were mixed with a 4 mol / L sodium sulfate solution. The mixture was then dried at 180 °C in a tumbler, resulting in large granules. The granules were roasted in a muffle furnace at 600 °C for 2 hours. The roasted material is then mixed with water at a solid / liquid ratio of 1 / 3. The mixture was stirred at room temperature for 30 min. Subsequently, the mixture was filtered, and the filter cake was mixed with an acidic solution at a solid / liquid ration of 1 / 5. The mixture was stirred at 80 °C for 1 hour with the pH maintained at 5.0. Afterwards, the mixture was filtered, and the filter cake was rinsed. The resulting filtrates and rinsing solutions were mixed, leading to a solution has a pH of around 5.6. The mixed solution was then processed through solvent extraction using an extractant suitable for lithium extraction under neutral and acidic conditions, leading to a solution rich in lithium and a raffinate rich in aluminum and silicon. The lithium-rich solution was mixed with a sodium carbonate solution of 3.5 mol / L at a volumetric ratio of 1 / 2. The resulting precipitate was filtered and washed with deionized water. The filter cake was re-dispersed in deionized water at a solid / liquid ratio of 1 :5. The filter was mixed with lime mix to form a uniform slurry. The slurry was continuously mixed at 100 °C for 1 hour. Deionized water was frequently added during the process to maintain the slurry state. Subsequently,the slurry was filtered, and the filter cake was rinsed with deionized water. The filtrate and rinsing water were mixed and processed in MVR, resulting in a crude lithium hydroxide monohydrate product. The product was re-dissolved in deionized water. The undissolved solids were removed by filtration, and then, the filtrate was re-processed in MVR, resulting in a pure lithium hydroxide monohydrate product. The product was treated in a muffle furnace at around 150 °C, leading to a final lithium hydroxide product. Elemental analysis showed that the product has a purity of 99.83%.

[0120] The raffinate obtained from solvent extraction was processed to recover aluminum and silicon. The pH of the solution was reduced to around 3.0. The resulting precipitates were collected by filtration followed by washing with a weakly acidic solution. The filter cake was thermally dried at 60 °C. Elemental analysis showed that the dried product was 99.97% pure silicon oxide. The filtrate was mixed with the washing solution. The mixed solution was fed to cation-exchange columns. After multiple stages of adsorption and desorption, a solution rich in relatively pure aluminum (>99%) was obtained. An aluminum hydroxide product of 99.5% purity was obtained from the solution through MVR.

[0121] Embodiments disclosed herein may provide at least the following advantages: 1). Staged precipitation using either CO2 or ordinary acids followed by purification to produce high-purity AI2O3 and SiCh; 2.) production of high-purity sodium carbonate from the alkaline raffinate by using CO2 as the precipitant followed by evaporation; and 3) One-stage precipitation followed by washing and purification to produce high-purity AI2O3 and SiO2 mix or individual AI2O3 and SiO2 product.

[0122] Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from the disclosed subject matter. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.

Claims

CLAIMSWhat is claimed:

1. A method comprising: pretreating ground lithium-containing ceramics to form alkali coated ceramics; leaching the alkali coated ceramics to form a leachate comprising a filtrate and a solid residue, preferentially extracting lithium from the filtrate to form a lithium rich solution and a raffinate; precipitating a crude lithium carbonate from the lithium rich solution; and purifying the crude lithium carbonate to produce a battery grade lithium carbonate.

2. The method of claim 1, further comprising: extracting and purifying AI2O3, SiCh, Na2CCh and other value components from the raffinate with staged precipitation.

3. The method of claim 1, wherein the pretreating comprises: soaking the ground lithium-containing ceramics in an alkali solution to form uniformly coated ground ceramics; and alkali roasting the uniformly coated ground ceramics at a temperature ranging from 200 to 500°C, thereby forming the alkali coated ceramics.

4. The method of claim 1, wherein the leaching comprises: leaching the alkali coated ceramics with water to produce a first portion of lithium; leaching the alkali coated ceramics with a weak acid to produce a second portion of lithium, and filtering the leachate obtained from both leaching steps to form the filtrate and the solid residue.

5. The method of claim 1, wherein the preferentially extracting lithium to form the lithium rich solution comprises at least one of:separating lithium with a liquid extractant; and separating lithium with an adsorbent resin and desorbing the lithium.

6. The method of claim 5, wherein the liquid extractant is an alkaline extractant.

7. The method of claim 1, wherein the purifying the crude lithium carbonate comprises: dissolving the crude lithium carbonate in the presence of a solution including carbon dioxide to form a lithium bicarbonate solution; filtering undissolved components from the lithium bicarbonate solution; and removing the carbon dioxide from the lithium bicarbonate solution to isolate battery grade lithium carbonate.

8. The method of claim 2, wherein the extracting and purifying AI2O3, SiCh, Na2COs and other value components from the raffinate comprises: performing staged carbonation on the raffinate or treating the raffinate with a mineral acid; wherein performing staged carbonation on the raffinate comprises: treating the raffinate with carbon dioxide at least once to reduce a pH of the raffinate to a target pH; filtering the raffinate to recover solid AI2O3, SiCh, and liquid filtrate; and evaporating the liquid filtrate to recover sodium carbonate.

9. A method comprising: leaching a slurry comprising lithium-containing ceramics, water, a strong base, and an alkaline earth metal oxide / hydroxide at a pressure ranging from 0 to 1450 psi and at a temperature ranging from 100 to 500°C to form a leached slurry comprising a liquid filtrate and a solid residue; processing the liquid filtrate to recover a lithium-rich organic solution; and processing the lithium-rich organic solution to produce a battery-grade lithium compound and sodium sulfate.

10. The method of claim 9, wherein leaching the slurry further comprises: filtering the leached slurry to separate the liquid filtrate from the solid residues; andremoving impurities from the liquid filtrate, wherein the impurities comprise at least one of Ca, Mg, Al, or Fe.

11. The method of claim 10, wherein removing impurities comprises at least one of selective precipitation, selective adsorption, or membrane-based methods.

12. The method of claim 9, wherein the processing the liquid filtrate comprises: extracting lithium from the liquid filtrate with an extractant to produce an organic phase and a raffinate; removing the raffinate; scrubbing the organic phase with a scrubbing solution; and removing the scrubbing solution to provide the lithium-rich organic solution.

13. The method of claim 9, wherein the processing the lithium-rich organic solution to produce a battery-grade lithium compound comprises: stripping the lithium-rich organic solution with sulfuric acid, precipitating lithium carbonate, and refining the lithium carbonate.

14. The method of claim 9, wherein processing the lithium- rich organic solution to produce a battery-grade lithium compound comprises: mixing the lithium-rich organic solution with carbon dioxide to form a suspension comprising lithium carbonate, separating the lithium carbonate from the suspension, and de-oiling the lithium carbonate.

15. The method of claim 9, wherein processing the lithium-rich organic solution to produce a battery-grade lithium compound comprises: mixing the lithium-rich organic solution with carbon dioxide in the presence of an aqueous solution, transferring lithium from the lithium-rich organic solution to the aqueous solution, de-oiling the aqueous solution, andperforming mechanical vapor recompression on the aqueous solution to obtain lithium carbonate.

16. The method of claim 9, wherein processing the lithium- rich organic solution to produce a battery-grade lithium compound comprises: stripping the lithium-rich organic solution with a solution comprising hydrogen peroxide to transfer lithium to the solution , de-oiling the solution, and performing mechanical vapor recompression on the solution to obtain the battery-grade lithium compound comprising lithium hydroxide.

17. The method of claim 9, wherein the lithium-containing ceramics are prepared through crushing and / or grinding to reduce to a particle size range below 50 mesh.

18. The method of claim 9, wherein the strong base is selected from the group consisting of sodium hydroxide, potassium hydroxide, and combinations thereof.

19. The method of claim 9, wherein the alkaline earth metal oxide / hydroxide is selected from the group consisting of calcium oxide, calcium hydroxide, magnesium oxide, magnesium hydroxide, and combinations thereof.

20. The method of claim 9, wherein the leaching is performed for a time ranging from 1 second to 12 hours.

21. The method of claim 12, wherein the extracting occurs in multiple stages configured in a counter-current, co-current, or a combination of both arrangements.

22. The method of claim 12, wherein the extractant is selected from di-(2-ethylhexyl) phosphoric acid, tri-n-butyl phosphate, tricaprylmethylammonium chloride, an ionic liquid, or a synergistic extractant system.

23. The method of claim 12, wherein the scrubbing step occurs in multiple stages configured in a counter-current, co-current, or a combination of both arrangements.

24. The method of claim 12, wherein the scrubbing solution comprises relatively pure water and / or dilute acid .

25. The method of claim 10, wherein the filtering the leached slurry further comprises: washing the solid residues by re-dispersing solid particles in solution followed by solid / liquid separation.

26. The method of claim 25, wherein the washing comprises a multiple staged configured in a counter-current arrangement.

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