Process for producing lithium carbonate

Abstract

A process for producing lithium carbonate, including: producing a lithium chloride containing solution; in the presence of a monovalent (M+) hydroxide, contacting this solution with a first organic medium, in an extraction step of a lithium solvent extraction stage, to produce a lithium-loaded organic medium and a raffinate; treating the raffinate to produce a treated raffinate; in a stripping step of the lithium solvent extraction stage, stripping the lithium-loaded organic medium by means of an aqueous stripping solution containing an acid, to extract the lithium cations from the lithium-loaded organic medium, producing an aqueous lithium chloride solution and a stripped organic medium; separating this solution from the stripped organic medium; recycling the stripped organic medium to the extraction stage; reacting the lithium chloride solution with carbonate to produce lithium carbonate and a mother liquor containing chloride, carbonate, and a monovalent cation; and subjecting the treated raffinate to chlor-alkali electrolysis.

Description

[0001] Process for Producing Lithium Carbonate

[0002] FIELD AND BACKGROUND OF THE INVENTION

[0003] The present invention relates to processes for producing lithium carbonate, and, more particularly, to processes for producing lithium carbonate using hydrochloric acid produced in-situ.

[0004] SUMMARY OF THE INVENTION

[0005] According to some teachings of the present invention there is provided a process for producing lithium carbonate from a lithium-containing raw material, the process including: (a) processing the lithium-containing raw material in a raw material processing section to produce a crude aqueous solution containing lithium chloride; (b) in the presence of a monovalent (M+) hydroxide, contacting the crude aqueous solution with a first organic medium, in an extraction step of a lithium solvent extraction stage, to produce: (i) a lithium-loaded organic medium; and (ii) a raffinate; wherein M+is selected from the group consisting of at least one of sodium, potassium, and ammonium; (c) treating the raffinate to produce a treated raffinate; (d) in a stripping step of the lithium solvent extraction stage, stripping the lithium-loaded organic medium by means of an aqueous stripping solution containing an acid, to extract the lithium cations from the lithium-loaded organic medium, producing: (i) an aqueous lithium chloride solution; and (ii) a stripped organic medium; (e) separating the aqueous lithium chloride solution from the stripped organic medium; and (f) recycling the stripped organic medium to the extraction stage, the first organic medium including the stripped organic medium.

[0006] According to some teachings of the present invention the process may further include subjecting the treated raffinate to chlor-alkali electrolysis to produce hydrogen gas, chlorine gas, and a monovalent hydroxide stream containing the monovalent (M+) hydroxide.

[0007] According to some teachings of the present invention the process may further include reacting the hydrogen gas and chlorine gas to produce HC1. According to some teachings of the present invention the process may further include dissolving the hydrogen chloride in water to produce HC1 solution.

[0008] According to some teachings of the present invention the process may further include reacting the aqueous lithium chloride solution with a carbonate to produce lithium carbonate and a mother liquor containing chloride and carbonate, and a monovalent cation selected from the group consisting of at least one of sodium, potassium, and ammonium; and returning at least a portion of the mother liquor for use within the process.

[0009] BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. Throughout the drawings, like-referenced characters are used to designate like elements.

[0011] In the drawings:

[0012] Figure 1 is a schematic conceptual block diagram of a process for producing lithium carbonate, according to aspects of the present invention.

[0013] DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The principles and operation of the processes according to the present invention may be better understood with reference to the drawings and the accompanying description.

[0015] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

[0016] Also, while sodium, sodium hydroxide and the like are used in the below- provided description, for the purpose of simplification, it must be emphasized that these terms are meant to include all of the heavier alkali metals (e.g., potassium, rubidium, and cesium) and their corresponding hydroxides, respectively.

[0017] A method of extracting lithium cations from an aqueous feed solution, followed by stripping, is provided in PCT Patent Publication Nos. WO / 2013 / 065050 and WO / 2017 / 137885, which are incorporated by reference for all purposes as if fully set forth herein. PCT Patent Publication No. WO / 2017 / 137885 also provides for downstream processing of the aqueous lithium solution produced in the stripping operation.

[0018] While these methods are fundamentally sound, the present inventors have identified various deficiencies therein, and in the art of aqueous lithium solution production as a whole.

[0019] Turning now to Figure 1, Figure 1 is a schematic conceptual block diagram of a process for producing lithium carbonate, according to aspects of the present invention.

[0020] A lithium-containing raw material is processed in a Raw Material Processing (RMP) Stage. In some embodiments, the lithium-containing raw material includes, mainly includes, consists essentially of or consists of a lithium-containing ore such as petalite (LiAl(Si20s)2), lepidolite (K(Li,Al)3(Al,Si,Rb)40io(F,OH)2), spodumene (LiAl(SiO3)2), or combinations thereof.

[0021] The leaching may be performed with HC1, and more typically, with an HC1 solution. Depending on the lithium-containing raw material, as well as impurities therein, various additional processing steps may be performed. For example, in the case of Ca, Mg, and Al, a chemical precipitation or pH elevation step — typically using NaOH — may be utilized to precipitate them out as a hydroxide or — using Na2CC>3 or other soluble carbonate — as a carbonate salt precipitate. The precipitate is typically removed as a waste stream. Solvent Extraction (SX) may be used, as is known in the art, for removal of heavy metals (e.g., cobalt, copper, nickel, manganese) present in the lithium-containing raw material. Ion exchange (IX) may be used, as is known in the art, for removal of remaining bi-valent and multi-valent cations, prior to feeding the pregnant lithium sulfate solution into the Lithium Solvent Extraction (Li SX) stage. The sodium and potassium present in the raw materials of the RMP Stage typically behave in a qualitatively similar fashion to the lithium, and are passed on, in solution, to the lithium extraction step described hereinbelow.

[0022] The choice of the lithium-containing raw material(s) may appreciably influence the composition of the impurities present, as well as the concentration of those impurities. Depending on the composition of these impurities, a number of different purification methods may be required. Calcium, magnesium, aluminum and iron may be removed by pH adjustment using sodium hydroxide and / or sodium carbonate (e.g., to precipitate a hydroxide and / or a carbonate salt). In the case of iron, an oxidation step may be required to produce ferric ions, so as to facilitate precipitation.

[0023] In some embodiments, nano-filtration may be used as a pre-treatment step to reduce the loading and quantity of reagents in the precipitation step.

[0024] In some embodiments, ion exchange may used as a post-treatment polishing step.

[0025] If any of copper, nickel, cobalt, and manganese are present, solvent extraction may be utilized to purify the solution while obtaining a valuable, metal-containing byproduct.

[0026] The product solution of the raw material processing stage is a crude aqueous lithium chloride solution, typically at elevated pH. This solution typically contains an appreciable contaminant concentration of one or more alkali metals, typically sodium. This purified solution may be introduced to the lithium solvent extraction (LiSX) stage, which includes an extraction step followed by a stripping step. The LiSX stage produces a lithium-loaded organic solution and an aqueous raffinate stream.

[0027] In the extraction step, the aqueous lithium-containing solution is mixed with an extracting organic solution to produce a lithium-loaded organic solution. The lithium- loaded organic solution may typically include at least one organic species of the form R -Li+, wherein R' is an organic proton acceptor or wherein R is an organic proton donor. This process is highly selective with respect to lithium. All anions, and cations other than lithium (e.g., boron, sodium, ammonium and potassium) selectively report to the aqueous raffinate.

[0028] In some embodiments, R may include, mainly include, consists essentially of, or consist of an alcohol, a ketone, an aldehyde, a carboxylic acid, or other organic materials that may be recognized or found to be suitable by those of ordinary skill in the art. Specific examples include isoamyl alcohol, glycerol, methyl-isobutyl ketone (MIBK), thenoyl trifluoroacetone, and benzoyl acetone.

[0029] It will be further appreciated by those of ordinary skill in the art that various substitutions may be made in the various species (R‘) that associate with the lithium ion, such that R or R' may include atoms or ligands other than C, H, and O. For example, substitutions, or in some cases, multiply-substitutions may be made in R or R', by atoms or ligands such as Cl, Br, I, N, P and S. Typically, Cl, Br, and I may replace hydrogen. N, P and S may be disposed in the backbone or may be attached to the backbone, for example, as part of a branch.

[0030] An appreciable quantity of a higher (z.e., with respect to lithium) alkali hydroxide (e.g., NaOH, KOH) or ammonium hydroxide may be required to control pH within the extraction step and — significantly — to condition the extractant. We have found that a soluble carbonate such as at least one of sodium, potassium, and ammonium carbonate may advantageously be employed in the extraction step.

[0031] The lithium-loaded organic phase discharged from the extraction step is optionally washed and scrubbed to selectively remove cationic impurities, before being introduced to the stripping step, in which HC1 solution may be utilized to liberate the loaded lithium from the organic phase. A relatively pure, aqueous lithium chloride solution may be produced. The organic phase, which may be stripped of nearly all of its lithium (“stripped organic solution”), is returned to an earlier process step, typically to the lithium extraction step.

[0032] In some embodiments, the lithium-loaded organic solution discharged from the solvent extraction step is introduced directly into the stripping step, z.e., without undergoing an intermediate scrubbing process. In some embodiments, the (purified) aqueous lithium chloride solution is the main lithium product of the process.

[0033] In some embodiments, the aqueous lithium chloride solution may be further processed to produce various lithium-containing products, as will be appreciated by those of skill in the art.

[0034] In the context of the present invention, we have found it to be particularly advantageous to subject the lithium chloride solution to a carbonization process to produce lithium carbonate. Typically, the lithium chloride solution is reacted with a water-soluble or dissolved carbonate, precipitating lithium carbonate. The lithium carbonate solids may be separated from the mother liquor and may undergo purification (e.g., washing) to remove contaminants in the aqueous phase adhering to the lithium carbonate solids, followed by drying.

[0035] The water-soluble or dissolved carbonate may be prepared from a variety of raw materials known to those of skill in the art, including at least one of Na2COs, (NHThCCh, and K2CO3, (typically starting from Na2CO3(S), (NHf CChcs), and K2CO3(S)). Various purification steps may be utilized to reduce the concentration of contaminants, as is known to those of skill in the art.

[0036] The carbonization mother liquor contains the chloride from the lithium chloride reactant, a monovalent cation from the carbonate feed (typically at least one of Na+, NH4+, and / or K+, most typically, Na+), excess carbonate, and various impurities.

[0037] In some embodiments, at least a portion of the mother liquor is utilized within the process.

[0038] In some embodiments, at least a portion of the mother liquor is introduced to the lithium extraction stage.

[0039] In some embodiments, at least a portion of the mother liquor is introduced to the the raw material processing stage.

[0040] In some embodiments, at least a portion of the mother liquor is introduced to the the pH elevation step, or to the pH elevation and polishing step, of the raw material processing stage.

[0041] With reference now to the aqueous raffinate stream (“raffinate”), the raffinate may be a particularly problematic stream, containing a host of anions, and cations (e.g., boron, sodium, ammonium and potassium), as well as lithium itself, albeit at a relatively low concentration. The raffinate may further contain organic matter, primarily from the solvent extraction step.

[0042] Significantly, we have found that the raffinate may contain an appreciable concentration of carbonate, primarily, but not exclusively, from the carbonization mother liquor.

[0043] Consequently, and particularly in view of the high concentration of carbonate, the raffinate is essentially a liability, and may be considered to be a waste stream, or a necessary process bleed stream.

[0044] We have discovered that with particular pre-processing, however, that the raffinate can be converted into a feed stream for a chlor-alkali process in which, from the processed raffinate, a monovalent hydroxide (e.g., at least one of NaOH, NH4OH, and KOH) is produced, along with hydrogen and chlorine gas. The hydrogen and chlorine gas may be reacted to produce HCl(g). The HCl(g) may be dissolved in water to produce HC1 solution. Various concentrations may be made up, depending on the particular needs of the relevant process stages. The HC1 may be of extremely high purity, as the HC1 is produced from hydrogen and chlorine gas that were produced in situ.

[0045] In some embodiments, a portion of the chlorine gas may be used to produce treated drinking water.

[0046] For the sake of simplicity, the monovalent hydroxide may be referred to as NaOH or sodium hydroxide in Figure 1 and in the associated description.

[0047] Initially, the raffinate discharged from the lithium extraction step may be subjected to one or more pre-treatment steps, to remove organic matter, silica, etc. The pre-treatment steps may include passing the stream through activated carbon, chemical precipitation (e.g., precipitation of fluoride as CaF2 by means of Ca+2), and ion exchange (for removing bi-valent and multi-valent cations), including combinations thereof.

[0048] We have found that the disadvantageous presence of carbonate (CO32) in the raffinate may be remedied by reducing the pH of the raffinate (e.g., with HC1 solution from the chlor-alkali product) to around 4 or below, whereby carbon dioxide is liberated.

[0049] While the raffinate has a disadvantageously low concentration of sodium chloride for the chlor-alkali process, the raffinate may be subjected to pre-concentration to raise the sodium chloride concentration into a desirable range (e.g., 25 to 26%, by weight).

[0050] The processed raffinate may then then be introduced to the the chlor-alkali process. It will be appreciated that those of skill in the art are familiar with various kinds of chlor-alkali processes, including membrane cell, diaphragm cell, and mercury cell processes.

[0051] The HC1 or HC1 solution produced may be particularly suitable for in-process use, including leaching operations, stripping operations, and ion exchange regeneration. Moreover, the in situ generation of HC1 and NaOH may essentially obviate the heavy transportation costs to bring these reagents to the lithium processing site.

[0052] As used herein in the specification and in the claims section that follows, the term “predominant cation”, with respect to a solution, refers to a cation having the highest molar concentration within that solution.

[0053] As used herein in the specification and in the claims section that follows, the term “predominant anion”, with respect to a solution, refers to an anion having the highest normal concentration within that solution. Except in the lithium hydroxide and sodium hydroxide solutions, and in the lithium-containing aqueous intermediate solution produced in the lithium stripping step, when acids other than hydrochloric acid may be utilized, the predominant anion tends to be chloride.

[0054] As used herein in the specification and in the claims section that follows, the term “membrane electrolysis” is meant to include processes in which ions are transported through at least one ion-exchange membrane under the driving force of a direct current and an applied potential.

[0055] As used herein in the specification and in the claims section that follows, the term “R ”, with respect to a species “R” having a functional group, refers to a moiety identical to “R”, but with one less hydrogen atom at the site of that functional group. Thus, for example, when R is butyric acid (H3C-CH2-CH2-COOH), also represented as then R' would be represented by H3C-CH2-CH2-COO'.

[0056] As used herein in the specification and in the claims section that follows, the term “monovalent”, with respect to a hydroxide, refers to the cation associated with the hydroxide. This cation is typically at least one of sodium (Na+), ammonium (NH4+), and potassium (K+). Most typically, this cation is predominantly sodium.

[0057] As used herein in the specification and in the claims section that follows, the term “percent”, or “%”, refers to weight-percent, unless specifically indicated otherwise.

[0058] Similarly, the term “ratio”, as used herein in the specification and in the claims section that follows, refers to a weight ratio, unless specifically indicated otherwise.

[0059] Inventive Concepts

[0060] The present disclosure includes, inter alia, the following Inventive Concepts (“Embodiments”), which are listed below for convenient reference. While some concepts disclosed hereinabove may not summarized in this section, this should not be taken as an indication that such concepts are not inventive or not within the scope of the embodiments. Some of the Inventive Concepts are introduced below for the first time for the sake of conciseness.

[0061] Embodiment 1. A process for producing lithium carbonate from a lithium- containing raw material, the process including: (a) processing the lithium-containing raw material in a raw material processing section to produce a crude aqueous solution containing lithium chloride; (b) in the presence of a monovalent (M+) hydroxide, contacting the crude aqueous solution with a first organic medium, in an extraction step of a lithium solvent extraction stage, to produce: (i) a lithium-loaded organic medium; and (ii) a raffinate; wherein M+ is selected from the group consisting of at least one of sodium, potassium, and ammonium; (c) treating the raffinate to produce a treated raffinate; (d) in a stripping step of the lithium solvent extraction stage, stripping the lithium-loaded organic medium by means of an aqueous stripping solution containing an acid, to extract the lithium cations from the lithium-loaded organic medium, producing: (i) an aqueous lithium chloride solution; and (ii) a stripped organic medium; (e) separating the aqueous lithium chloride solution from the stripped organic medium; and (f) recycling the stripped organic medium to the extraction stage, the first organic medium including the stripped organic medium.

[0062] Embodiment 2. The process of Embodiment 1, further including subjecting the treated raffinate to chlor-alkali electrolysis to produce hydrogen gas, chlorine gas, and a monovalent hydroxide stream containing the monovalent (M+) hydroxide.

[0063] Embodiment 2A. The process of Embodiment 2, further including reacting the hydrogen gas and chlorine gas to produce hydrogen chloride (HC1).

[0064] Embodiment 2B. The process of Embodiment 2A, further including dissolving the hydrogen chloride in water to produce HC1 solution.

[0065] Embodiment s. The process of any one of the preceding Embodiments, further including reacting the aqueous lithium chloride solution with a carbonate to produce lithium carbonate and a mother liquor containing chloride, carbonate, and a monovalent cation selected from the group consisting of at least one of sodium, potassium, and ammonium, wherein the sodium, potassium, and ammonium monovalent cations optionally make up at least 80%, at least 90%, at least 95%, or at least 98% of the total amount of aqueous cations, by weight.

[0066] Embodiment 4. The process of Embodiment 3, further including returning at least a portion of the mother liquor for use within the process.

[0067] Embodiment 4A. The process of any one of the preceding Embodiments, further comprising separating the lithium-loaded organic medium from the raffinate.

[0068] Embodiment 4B. The process of any one of the preceding Embodiments, wherein the lithium-loaded organic medium is directly introduced into the stripping step, without undergoing intermediate scrubbing.

[0069] Embodiment s. The process of any one of Embodiments 1 to 4 A, further comprising, prior to the stripping, purifying the lithium-loaded organic medium in a scrubbing stage.

[0070] Embodiment 6. The process of any one of the preceding Embodiments, further comprising removing organic matter from the raffinate. Embodiment 7. The process of any one of Embodiments 2 to 6, wherein the concentration of M+within the monovalent hydroxide stream is within the range of 10% to 52%.

[0071] Embodiment 8. The process of Embodiment 7, wherein the concentration of M+within the monovalent hydroxide stream is within the range of 15% to 52%, 20% to 52%, 25% to 52%, 30% to 52%, 25% to 45%, 25% to 40%, or 25% to 33%.

[0072] Embodiment 9. The process of Embodiment 7, wherein the concentration of M+within the monovalent hydroxide stream is within the range of 37% to 52%.

[0073] Embodiment 10. The process of Embodiment 7, wherein the concentration of M+within the monovalent hydroxide stream is within the range of 22% to 40%.

[0074] Embodiment 11. The process of any one of the preceding Embodiments, wherein a portion of the HC1 solution is utilized within the process to regenerate an ion-exchange resin within the process.

[0075] Embodiment 12. The process of Embodiment 11, wherein the ion-exchange resin is disposed within the raw material processing section.

[0076] Embodiment 13. The process of Embodiment 12, wherein the ion-exchange resin is disposed within the raw material processing section, in a polishing step producing or prior to producing the crude aqueous solution.

[0077] Embodiment 14. The process of any one of Embodiments 11 to 13, wherein the ion-exchange resin is disposed within the raffinate treatment step, prior to introducing the treated raffinate to the chlor-alkali process.

[0078] Embodiment 15. The process of any one of the preceding Embodiments, wherein a portion of the HC1 solution is utilized in a leaching step within the raw material processing section.

[0079] Embodiment 16. The process of any one of the preceding Embodiments, wherein a portion of the monovalent hydroxide stream is utilized in a leaching step within the raw material processing section.

[0080] Embodiment 17. The process of any one of the preceding Embodiments, wherein a portion of the monovalent hydroxide stream containing the monovalent (M+) hydroxide is introduced to the lithium solvent extraction stage. Embodiment 18. The process of any one of the preceding Embodiments, further comprising regenerating an ion exchange unit within the process using a portion of the monovalent hydroxide stream containing the monovalent (M+) hydroxide.

[0081] Embodiment 19. The process of any of the preceding Embodiments, wherein the concentration of lithium within the raffinate is at least 2 ppm.

[0082] Embodiment 20. The process of Embodiment 19, wherein the concentration of lithium within the raffinate is at least 3 ppm.

[0083] Embodiment 21. The process of Embodiment 19, wherein the concentration of lithium within the raffinate is at least 5 ppm.

[0084] Embodiment 22. The process of Embodiment 19, wherein the concentration of lithium within the raffinate is at least 10 ppm.

[0085] Embodiment 23. The process of Embodiment 19, wherein the concentration of lithium within the raffinate is at least 20 ppm.

[0086] Embodiment 24. The process of any one of Embodiments 19 to 23, wherein the concentration of lithium within the raffinate is at most 500 ppm.

[0087] Embodiment 25. The process of any one of Embodiments 19 to 23, wherein the concentration of lithium within the raffinate is at most 250 ppm.

[0088] Embodiment 26. The process of any one of Embodiments 19 to 23, wherein the concentration of lithium within the raffinate is at most 150 ppm.

[0089] Embodiment 27. The process of any one of Embodiments 19 to 23, wherein the concentration of lithium within the raffinate is at most 100 ppm.

[0090] Embodiment 28. The process Embodiment 27, wherein the concentration of lithium within the raffinate is at most 60 ppm.

[0091] Embodiment 29. The process of any one of Embodiments 1 to 28, wherein the ratio (Ru) of lithium within the raffinate (Lir) to lithium within the crude aqueous solution (LiCr) is at least 0.01.

[0092] Embodiment 30. The process of Embodiment 29, wherein Ru is at least 0.02.

[0093] Embodiment 31. The process of Embodiment 29, wherein Ru is at least 0.03. Embodiment 32. The process of Embodiment 29, wherein Ru is at least 0.05.

[0094] Embodiment 33. The process of Embodiment 29, wherein Ru is at least 0.07.

[0095] Embodiment 34. The process of any one of Embodiments 29 to 33, wherein Ru is at most 0.10.

[0096] Embodiment 35. The process of Embodiment 34, wherein Ru is at most 0.08.

[0097] Embodiment 36. The process of any one of Embodiments 29 to 33, wherein Ru is at most 0.06.

[0098] Embodiment 37. The process of any one of the preceding Embodiments, wherein the lithium content (LIMVH) within the monovalent hydroxide stream is at least 4 ppm.

[0099] Embodiment 38. The process of Embodiment 37, wherein LIMVH is at least 8 ppm.

[0100] Embodiment 39. The process of Embodiment 37, wherein LIMVH is at least 12 ppm.

[0101] Embodiment 40. The process of Embodiment 37, wherein LIMVH is at least 25 ppm.

[0102] Embodiment 41. The process of Embodiment 37, wherein LIMVH is at least 60 ppm.

[0103] Embodiment 42. The process of any one of Embodiments 37 to 41, wherein LIMVH is at most 800 ppm.

[0104] Embodiment 43. The process of Embodiment 42, wherein LIMVH is at most 500 ppm.

[0105] Embodiment 44. The process of Embodiment 42, wherein LIMVH is at most 250 ppm.

[0106] Embodiment 45. The process of any one of the preceding Embodiments, wherein the concentration of sodium (or M+) within the HC1 solution is at most 10 ppm.

[0107] Embodiment 46. The process of any one of the preceding Embodiments, wherein the processing of the lithium-containing raw material includes leaching the lithium- containing raw material with HC1. Embodiment 47. The process of Embodiment 46, wherein a portion of the HC1 used to effect the leaching of the lithium-containing raw material is utilized from the HC1 solution.

[0108] Embodiment 48. The process of any one of the preceding Embodiments, wherein the lithium-containing raw material includes, or consists essentially of, a lithium ore.

[0109] Embodiment 49. The process of Embodiment 48, wherein the lithium ore includes, or consists essentially of, spodumene.

[0110] Embodiment 50. The process of Embodiment 48, wherein the lithium ore includes, or consists essentially of, petalite [LiAl(Si20s)2].

[0111] Embodiment 51. The process of Embodiment 48, wherein the lithium ore includes, or consists essentially of, lepidolite [K(Li,Al)3(Al,Si,Rb)40io(F,OH)2].

[0112] Embodiment 52. The process of any one of the preceding Embodiments, wherein the lithium-containing raw material includes, or consists essentially of, a lithium- containing waste or lithium-containing recycled material.

[0113] Embodiment 53. The process of any one of the preceding Embodiments, wherein the organic to acid volumetric ratio (ROIOA) within the stripping step stripping vessel is within a range of 60: 1 to 1 : 1.

[0114] Embodiment 54. The process of Embodiment 53, wherein RotoA is within a range of 60: 1 to 15:1.

[0115] Embodiment 55. The process of Embodiment 53, wherein RotoA is within a range of 60: 1 to 22:1.

[0116] Embodiment 56. The process of Embodiment 53, wherein RotoA is within a range of 60: 1 to 25:1.

[0117] Embodiment 57. The process of Embodiment 53, wherein RotoA is within a range of 60: 1 to 28:1.

[0118] Embodiment 58. The process of any one of the preceding Embodiments, wherein the lithium-loaded organic medium includes at least one organic species of the form R -Li+, wherein R' is an organic proton acceptor or wherein R is an organic proton donor. Embodiment 59. The process of Embodiment 58, wherein R includes, mainly includes, consists essentially of, or consists of an alcohol.

[0119] Embodiment 60. The process of Embodiment 59, wherein the alcohol includes at least one alcohol selected from the group consisting of a straight-chain alcohol, a branched alcohol, and a diol or polyol.

[0120] Embodiment 61. The process of Embodiment 59, wherein the alcohol includes at least one Ci-Cio alcohol.

[0121] Embodiment 62. The process of Embodiment 59, wherein R includes, mainly includes, consists essentially of, or consists of a ketone.

[0122] Embodiment 63. The process of Embodiment 62, wherein the ketone includes at least one ketone selected from the group consisting of a straight-chain ketone, a branched ketone, and a diketone or a polyketone.

[0123] Embodiment 64. The process of Embodiment 62 or 63, wherein the ketone includes at least one C3-C10 ketone.

[0124] Embodiment 65. The process of Embodiment 58, wherein R includes, mainly includes, consists essentially of, or consists of an aldehyde.

[0125] Embodiment 66. The process of Embodiment 65, wherein the aldehyde includes at least one aldehyde selected from the group consisting of a straight-chain aldehyde, a branched aldehyde, and a dialdehyde or polyaldehyde.

[0126] Embodiment 67. The process of Embodiment 65 or 66, wherein the aldehyde includes at least one C1-C10 aldehyde.

[0127] Embodiment 68. The process of Embodiment 58, wherein R includes, mainly includes, consists essentially of, or consists of a carboxylic acid.

[0128] Embodiment 69. The process of Embodiment 68, wherein the carboxylic acid includes at least one carboxylic acid selected from the group consisting of a straightchain carboxylic acid, a branched carboxylic acid, an aryl carboxylic acid, and a dicarboxylic acid or polycarboxylic acid.

[0129] Embodiment 70. The process of Embodiment 65 or 66, wherein the carboxylic acid includes at least one C1-C20 carboxylic acid. Embodiment 71. The process of Embodiment 68, wherein the carboxylic acid is a fatty acid.

[0130] Embodiment 72. The process of any one of Embodiments 68 to 71, wherein the carboxylic acid is selected from the group consisting of a saturated carboxylic acid, a monounsaturated carboxylic acid, and a polyunsaturated carboxylic acid.

[0131] Embodiment 73 The process of any one of the preceding Embodiments, wherein the chlor-alkali electrolysis includes membrane cell electrolysis.

[0132] Embodiment 74. The process of any one of the preceding Embodiments, wherein the chlor-alkali electrolysis includes diaphragm cell electrolysis.

[0133] Embodiment 75. The process of any one of the preceding Embodiments, wherein the chlor-alkali electrolysis includes mercury cell electrolysis.

[0134] Embodiment 76. The process of any one of the preceding Embodiments, further comprising recycling at least a portion of the HC1 solution for use within the process.

[0135] Embodiment 77. The process of any one of the preceding Embodiments, wherein the recycling of the HC1 solution includes introducing the HC1 solution to the stripping step.

[0136] Embodiment 78. The process of any one of the preceding Embodiments, wherein the recycling of the HC1 solution includes utilizing the HC1 solution in the treating of the raffinate.

[0137] Embodiment 79. The process of any one of the preceding Embodiments, further comprising recycling at least a portion of the monovalent hydroxide stream for use within the process.

[0138] Embodiment 80. The process of any one of the preceding Embodiments, wherein the recycling of the monovalent hydroxide stream includes feeding the monovalent hydroxide stream into the extraction step.

[0139] Embodiment 81. The process of any one of the preceding Embodiments, wherein the recycling of the monovalent hydroxide stream includes feeding the monovalent hydroxide stream into the raw material processing section. Embodiment 82. The process of any one of the preceding Embodiments, wherein the feeding the monovalent hydroxide stream into the raw material processing section includes feeding the monovalent hydroxide stream into a pH elevation and polishing stage within the raw material processing section.

[0140] Embodiment 83. The process of any one of the preceding Embodiments, further comprising removing a portion of the monovalent hydroxide stream as a product of the process.

[0141] Embodiment 84. The process of any one of the preceding Embodiments, wherein the treating the raffinate includes subjecting the raffinate to evaporation to concentrate the raffinate.

[0142] Embodiment 85. The process of any one of the preceding Embodiments, wherein the treating the raffinate includes acidifying the raffinate to reduce the pH of the raffinate to at most 4.5.

[0143] Embodiment 86. The process of any one of the preceding Embodiments, wherein the treating the raffinate includes driving off carbon dioxide.

[0144] Embodiment 87. The process of any one of the preceding Embodiments, wherein the pH of the treated raffinate is at most 4.2.

[0145] Embodiment 88. The process of any one of the preceding Embodiments, wherein the pH of the treated raffinate is at most 4.0.

[0146] Embodiment 89. The process of any one of the preceding Embodiments, wherein the pH of the treated raffinate is at most 3.8.

[0147] Embodiment 90. The process of any one of the preceding Embodiments, wherein the pH of the treated raffinate is at least 3.

[0148] Embodiment 91. The process of any one of the preceding Embodiments, wherein the treating the raffinate or acidifying the raffinate includes adding a portion of the HC1 solution to the raffinate.

[0149] Embodiment 92. The process of any one of the preceding Embodiments, wherein the raffinate from the extraction step contains at least 1% carbonate, on an anionic molar equivalent basis. Embodiment 93. The process of any one of the preceding Embodiments, wherein the raffinate contains at least 2% carbonate.

[0150] Embodiment 94. The process of any one of the preceding Embodiments, wherein the raffinate contains at least 4% carbonate.

[0151] Embodiment 95. The process of any one of the preceding Embodiments, wherein the raffinate contains at least 7% carbonate.

[0152] Embodiment 96. The process of any one of the preceding Embodiments, wherein the raffinate contains at least 10% carbonate.

[0153] Embodiment 97. The process of any one of the preceding Embodiments, wherein the raffinate contains at most 30% carbonate.

[0154] Embodiment 98. The process of any one of the preceding Embodiments, wherein the raffinate contains at most 20% carbonate.

[0155] Embodiment 99. The process of any one of the preceding Embodiments, wherein the raffinate contains at most 16% carbonate.

[0156] Embodiment 100. The process of any one of the preceding Embodiments, wherein the raffinate contains at most 12% carbonate.

[0157] Embodiment 101. The process of any one of the preceding Embodiments, wherein the concentration of M+ within the HC1 solution is at most 30 ppm.

[0158] Embodiment 102. The process of any one of the preceding Embodiments, wherein the concentration of M+ within the HC1 solution is at most 20 ppm.

[0159] Embodiment 103. The process of any one of the preceding Embodiments, wherein the concentration of M+ within the HC1 solution is at most 10 ppm.

[0160] Embodiment 104. The process of any one of the preceding Embodiments, wherein the concentration of M+ within the HC1 solution is at most 5 ppm.

[0161] Embodiment 105. The process of any one of the preceding Embodiments, wherein the chloride concentration within the monovalent hydroxide stream is at least 0.005%, by weight.

[0162] Embodiment 106. The process of any one of the preceding Embodiments, wherein the chloride concentration is at least 0.015%. Embodiment 107. The process of any one of the preceding Embodiments, 7wherein the chloride concentration is at least 0.2%.

[0163] Embodiment 108. The process of any one of the preceding Embodiments, wherein the chloride concentration is at least 0.8%.

[0164] Embodiment 109. The process of any one of the preceding Embodiments, wherein the chloride concentration is at most 2.5%.

[0165] Embodiment 110. The process of any one of the preceding Embodiments, wherein the chloride concentration is at most 1.5%.

[0166] Embodiment 111. The process of any one of the preceding Embodiments, wherein the M+ in the monovalent hydroxide stream is predominantly Na+, on a molar basis.

[0167] Embodiment 112. The process of any one of the preceding Embodiments, wherein the M+ is at least 95% Na+, on the molar basis.

[0168] Embodiment 113. The process of any one of the preceding Embodiments, wherein an HC1 content in the HC1 solution is at least 20%, by weight.

[0169] Embodiment 114. The process of any one of the preceding Embodiments, wherein the HC1 content is at least 23%.

[0170] Embodiment 115. The process of any one of the preceding Embodiments, wherein the HC1 content is at least 27%.

[0171] Embodiment 116. The process of any one of the preceding Embodiments, wherein the HC1 content is at least 30%.

[0172] Embodiment 117. The process of any one of the preceding Embodiments, wherein the HC1 content is at least 32%.

[0173] Embodiment 118. The process of any one of the preceding Embodiments, wherein the HC1 content is at most 41%.

[0174] Embodiment 119. The process of any one of the preceding Embodiments, wherein the HC1 content is at most 38%.

[0175] Embodiment 120. The process of any one of the preceding Embodiments, wherein an M+0H' concentration within the monovalent hydroxide stream is within a range of 10 to 52%. Embodiment 121. The process of any one of the preceding Embodiments, wherein the M+OH' concentration is at least 20%.

[0176] Embodiment 122. The process of any one of the preceding Embodiments, wherein the M+0H' concentration is at least 25%.

[0177] Embodiment 123. The process of any one of the preceding Embodiments, wherein the M+0H' concentration is at least 28%.

[0178] Embodiment 124. The process of any one of the preceding Embodiments, wherein the M+0H' concentration is at least 32%.

[0179] Embodiment 125. The process of any one of the preceding Embodiments, wherein the M+0H' concentration is at most 40%.

[0180] Embodiment 126. The process of any one of the preceding Embodiments, wherein the M+0H' concentration is at least 36%.

[0181] Embodiment 127. The process of any one of the preceding Embodiments, wherein the returning of the mother liquor for use within the process includes using the mother liquor in the extraction step of the lithium solvent extraction stage.

[0182] Embodiment 128. The process of any one of the preceding Embodiments, wherein the returning of the mother liquor for use within the process includes using the mother liquor in a pH elevation and polishing stage within the raw material processing section.

[0183] Embodiment 129. The process of any one of the preceding Embodiments, wherein the carbonate reacted with the aqueous lithium chloride solution is predominantly sodium carbonate.

[0184] Embodiment 130. The process of any one of the preceding Embodiments, wherein the carbonate reacted with the aqueous lithium chloride solution is predominantly ammonium carbonate.

[0185] Embodiment 131. The process of any one of the preceding Embodiments, wherein the carbonate reacted with the aqueous lithium chloride solution is predominantly potassium carbonate. Embodiment 132. The process of any one of the preceding Embodiments, wherein the predominant cation of the monovalent hydroxide within the monovalent hydroxide stream is sodium.

[0186] Embodiment 133. The process of any one of the preceding Embodiments, wherein the predominant cation of the monovalent hydroxide within the monovalent hydroxide stream is ammonium.

[0187] Embodiment 134. The process of any one of the preceding Embodiments, wherein the predominant cation of the monovalent hydroxide within the monovalent hydroxide stream is potassium.

[0188] Embodiment 135. The process of any one of the preceding Embodiments, wherein a portion of the HC1 or the HC1 solution is recycled to the stripping step.

[0189] Embodiment 136. The process of any one of the preceding Embodiments, wherein a portion of the HC1 or the HC1 solution is utilized within the process to regenerate an ion-exchange resin.

[0190] Embodiment 137. The process of any one of the preceding Embodiments, wherein a portion of the monovalent hydroxide in the monovalent hydroxide stream is utilized in the production of the lithium-loaded organic medium.

[0191] Embodiment 138. The process of any one of the preceding Embodiments, wherein a portion of the monovalent hydroxide in the monovalent hydroxide stream is introduced to the extraction stage.

[0192] Embodiment 139. The process of any one of the preceding Embodiments, further comprising regenerating an ion exchange unit within the process using a portion of the monovalent hydroxide in the monovalent hydroxide stream.

[0193] Embodiment 140. The process of any one of the preceding Embodiments, wherein the concentration of lithium within the raffinate is at least 5 ppm.

[0194] Embodiment 141. The process of any one of the preceding Embodiments, wherein the concentration of lithium within the raffinate is at least 10 ppm.

[0195] Embodiment 142. The process of any one of the preceding Embodiments, wherein the concentration of lithium within the monovalent hydroxide stream is at least 7 ppm. Embodiment 143. The process of any one of the preceding Embodiments, wherein the concentration of iron within the HC1 solution is at most 2 ppm.

[0196] Embodiment 144. The process of any one of the preceding Embodiments, wherein the concentration of M+within the HC1 solution is at least 75 ppm.

[0197] Embodiment 145. The process of any one of the preceding Embodiments, wherein the processing of the lithium-containing raw material includes leaching the lithium- containing raw material with a source of HC1, and wherein a portion of the source of HC1 used to effect the leaching of the lithium-containing raw material is utilized from the HC1 or the HC1 solution.

[0198] Embodiment 146. The process of any one of the preceding Embodiments, wherein the chlor-alkali electrolysis includes membrane cell electrolysis.

[0199] Embodiment 147. The process of any one of the preceding Embodiments, wherein the chlor-alkali electrolysis includes diaphragm cell electrolysis.

[0200] Embodiment 148. The process of any one of the preceding Embodiments, wherein the chlor-alkali electrolysis includes mercury cell electrolysis.

[0201] Embodiment 149. The process of any one of the preceding Embodiments, further comprising removing a bleed stream from the raffinate.

[0202] Embodiment 150. The process of any one of the preceding Embodiments, wherein the total utilization of the monovalent hydroxide stream within the raw material processing stage and the lithium solvent extraction stage is at least 35%.

[0203] Embodiment 151. The process of any one of the preceding Embodiments, wherein the utilization of the HC1 solution within the process is at least 30%.

[0204] Embodiment 152. The process of any one of the preceding Embodiments, wherein the total utilization of the HC1 solution within the raw material processing stage and the lithium solvent extraction stage is at least 50%.

[0205] Embodiment 153. The process of any one of the preceding Embodiments, further comprising removing a portion of the monovalent hydroxide stream as a product of the process. The modifier "about" and “substantially” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (for example, it includes at least the degree of error associated with the measurement of the particular quantity). When used with a specific value, it should also be considered as disclosing that value.

[0206] In the context of the present application and claims, the phrase "at least one of A and B" is equivalent to an inclusive "or", and includes any one of "only A", "only B", or "A and B". Similarly, the phrase "at least one of A, B, and C" is equivalent to an inclusive "or", and includes any one of "only A", "only B", "only C", "A and B", "A and C", "B and C", or "A and B and C".

[0207] It will be appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

[0208] Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification, including PCT Patent Publication Nos. W02013065050, WO20 15123762 and WO2017137885, are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.

Claims

WHAT IS CLAIMED IS:

1. A process for producing lithium carbonate from a lithium-containing raw material, the process comprising:(a) processing the lithium-containing raw material in a raw material processing section to produce a crude aqueous solution containing lithium chloride;(b) in the presence of a monovalent (M+) hydroxide, contacting said crude aqueous solution with a first organic medium, in an extraction step of a lithium solvent extraction stage, to produce:(i) a lithium-loaded organic medium; and(ii) a raffinate; wherein M+is selected from the group consisting of at least one of sodium, potassium, and ammonium;(c) treating said raffinate to produce a treated raffinate;(d) in a stripping step of said lithium solvent extraction stage, stripping said lithium-loaded organic medium by means of an aqueous stripping solution containing an acid, to extract said lithium cations from said lithium-loaded organic medium, producing:(i) an aqueous lithium chloride solution; and(ii) a stripped organic medium;(e) separating the aqueous lithium chloride solution from said stripped organic medium;(f) recycling said stripped organic medium to said extraction stage, said first organic medium including said stripped organic medium;(g) reacting the aqueous lithium chloride solution with a carbonate to produce lithium carbonate and a mother liquor containing chloride, carbonate, and a monovalent cation selected from the group consisting of at least one of sodium, potassium, and ammonium;(h) returning at least a portion of said mother liquor for use within the process; and(i) subjecting said treated raffinate to chlor-alkali electrolysis to produce hydrogen gas, chlorine gas, and a monovalent hydroxide stream containing said monovalent (M+) hydroxide.

2. The process of claim 1, further comprising reacting said hydrogen gas and chlorine gas to produce HC1, and dissolving said hydrogen chloride in water to produce HC1 solution.

3. The process of claim 2, further comprising recycling at least a portion of said HC1 solution for use within the process, wherein said recycling of said HC1 solution includes introducing said HC1 solution to said stripping step, and / or utilizing said HC1 solution in said treating of said raffinate.

4. The process of any one of claims 1 to 3, further comprising recycling at least a portion of said monovalent hydroxide stream for use within the process, wherein said recycling of said monovalent hydroxide stream includes at least one of feeding said monovalent hydroxide stream into said extraction step and feeding said monovalent hydroxide stream into said raw material processing section.

5. The process of claim 4, further comprising removing a portion of said monovalent hydroxide stream as a product of the process.

6. The process of any one of claims 1 to 5, wherein said treating said raffinate includes subjecting said raffinate to evaporation to concentrate said raffinate.

7. The process of any one of claims 1 to 6, wherein said treating said raffinate includes acidifying said raffinate to reduce the pH of the raffinate to at most 4.5.

8. The process of claim 6 or 7, wherein said treating said raffinate includes driving off carbon dioxide.

9. The process of any one of claims 2 to 8, wherein said treating said raffinate or acidifying said raffinate includes adding a portion of said HC1 solution to said raffinate.

10. The process of any one of the preceding claims, wherein said raffinate from said extraction step contains carbonate within a range of 1 to 20%, on an anionic molar equivalent basis.

11. The process of any one of claims 2 to 10, wherein the concentration of M+within said HC1 solution is at most 30 ppm.

12. The process of any one of the preceding claims, wherein the chloride concentration within said monovalent hydroxide stream is within a range of 0.005% to 2.5%, by weight.

13. The process of any one of claims 2 to 12, wherein an HC1 content in said HC1 solution is at least 20%, by weight.

14. The process of any one of the preceding claims, wherein an M+0H' concentration within said monovalent hydroxide stream is within a range of 10 to 52%.

15. The process of any one of the preceding claims, wherein said returning of said mother liquor for use within the process includes using said mother liquor in said extraction step of said lithium solvent extraction stage, and / or said returning of said mother liquor for use within the process includes using said mother liquor in a pH elevation and polishing stage within said raw material processing section.

16. The process of any one of claims 2 to 15, wherein a portion of said HC1 or said HC1 solution is recycled to said stripping step and / or a portion of said HC1 or said HC1 solution is utilized within the process to regenerate an ion-exchange resin.

17. The process of any one of claims 2 to 16, wherein a portion of said monovalent hydroxide in said monovalent hydroxide stream is utilized in the production of said lithium-loaded organic medium and / or further comprising regenerating an ion exchange unit within the process using a portion of said monovalent hydroxide in said monovalent hydroxide stream.

18. The process of any one of claims 1 to 17, wherein the concentration of lithium within said raffinate is at least 5 ppm.

19. The process of any one of claims 3 to 18, wherein the concentration of M+within said HC1 solution is at least 75 ppm.

20. The process of any one of claims 1 to 19, wherein the utilization of said monovalent hydroxide stream within the process is at least 20%, and / or the total utilization of said monovalent hydroxide stream within the raw material processing stage and the lithium solvent extraction stage is at least 35%.

21. The process of any one of claims 1 to 20, wherein the utilization of said HC1 solution within the process is at least 30%, and / or the total utilization of said HC1 solution within the raw material processing stage and the lithium solvent extraction stage is at least 50%.

22. The process of any one of claims 2 to 21, wherein said processing of the lithium-containing raw material includes leaching the lithium-containing raw material with a source of HC1, and wherein a portion of said source of HC1 used to effect said leaching of the lithium-containing raw material is utilized from said HC1 or said HC1 solution.