Method of making lithium hydroxide and lithium carbonate

Abstract

The present invention relates to a method of making lithium hydroxide from lithium salts by reacting a lithium salt with an alkali metal hydroxide in an aqueous solution in the presence of ammonia.

Description

Method of making Lithium Hydroxide and Lithium CarbonateDescriptionThe increasing popularity of lithium-ion batteries has increased their useand also the desire to recycle its components from spent batteries for reusein the manufacturing of new batteries.Li2CO3 and LiOH are the main Li compounds used in Li-ion battery manufac-turing. The precipitation of Li2CO3 using soda ash (Na2CO3) has been com-monly used for Li2CO3 production in industry. However, this method re-quires an elevated temperature, and the resulting Li2CO3 is highly contami-nated with Na, see Tawonezvi, T., Zide, D., Nomnqa, M., Madondo, M.,Petrik, L., & Bladergroen, B. J., Chemical Engineering Journal Advances, 17,(2024), 100582.Compared to Li2CO3, LiOH is often preferred in the battery manufacturingindustries, especially for the synthesis of nickel-rich cathodes, because itallows for fast and complete synthesis of the cathode materials at lowertemperatures. This technical process is general technical knowledge of theartisan and published, for example, in: U. Wietelmann, R. Bauer, "Lithiumand Lithium compounds" in: Ullmann's Encyclopedia of Industrial Chemistry,2000.The production of LiOH typically includes the reaction between Li2CO3 andCa(OH)2, with the formation of CaCO3 as a residue. Disadvantage of thisprocess is its poor production yields and losses of Li2CO3 with CaCO3.Another method to obtain lithium hydroxide involves reacting lithium sulfate(Li2SO4), often derived from leachates of Li ores and spent Li-ion batteries,with sodium hydroxide (NaOH). Sodium sulfate (Na2SO4) is subsequentlyremoved through cooling crystallization, and lithium hydroxide monohydrate(LiOH H2O) is obtained via evaporation. The reaction can be represented asthe formula:Li2SO4 (aq) + 2NaOII (aq) + 121120→ Na2SO4 121120 (s) + 2LIOI1I120(s)The disadvantages of this method are that the combination of cooling andevaporative crystallization makes LiOH production cumbersome and resultsin a low purity of LiOH.Moreover, electrochemical methods, which produce less waste, have beendeveloped in the last decade as an alternative to classical precipitation andcrystallization methods. For instance, electrodialysis (ED) treatment of aLi2SO4 solution results in the cathode chamber enriched with LiOH. Thenevaporative crystallization following electrodialysis is used to produce Li-OH H2O, see Ang, K. L., Barmi, M., Boroumand, Y., Razmjou, A., & Nikoloski,A. N., Desalination and water treatment 320, (2024),100778.US 11339481 shows other new technologies that also allow LiOH to be pro-cessed from Li resources, such as technical grade LiCl, brine, more directlybypassing the Li2CO3 intermediate. However, multi-step purification or crys-tallization is still necessary.Overall, existing lithium hydroxide and lithium carbonate production pro-cesses can be complex and not energy-efficient, requiring multi-step crys-tallization and washing to remove impurities in the products.It was an objective of the invention to overcome the shortcomings of theknown reactions and to provide a method for preparing lithium hydroxideand lithium carbonate from other lithium salts such as and lithium car-bonate, lithium sulfate, nitrate, halides and mixtures thereof with high puri-ties, yields and preferably a simpler setup.It was surprisingly found that this problem can be solved by a method ofmaking lithium hydroxide from lithium salts by reacting a lithium salt withan alkali metal hydroxide, wherein the alkali metal hydroxide is an alkalimetal hydroxide other than lithium hydroxide in aqueous solution, whereingaseous ammonia is added.It was surprisingly found that lithium salts like LiCl and Li2SO4 can be direct-ly converted to LiOH in an aqueous solution after dissolving of ammonia gasin the solution, in which alkali metal sulfate or chloride will crystallize direct-ly at room temperature and a relatively pure LiOH solution can be obtained.The reaction is carried out at a reaction temperature from about 10°C toabout 60°C, or from 20°C to about 50°C or from about 25°C to about 45°C,or the reaction temperature is from 20°C to 70°C, from 30°C to 60°C orfrom 40°C to 50°C. Usually, simply allowing the reaction at ambient tem-perature has shown to be practical and the reaction mixture will slightywarm itself as it is exothermic. The reaction time is from 15 minutes to 15hours, or 30 minutes to 6 hours, or from 40 minutes to 1 hour.This allows corresponding alkali metal salts such as halides or sulfates, likeNaCl, KCI, K2SO4 and Na2SO4 to crystallize at the reaction temperature for itto be removed by e.g. filtration, followed by evaporative crystallization ofLiOH. The evaporative crystallization can be facilitated by carrying out theevaporative crystallization at reduced pressure.To reduce loss of lithium, lithium in the mother liquor of LiOH crystallizationcan be recovered by Li2CO3 precipitation, which can be accomplished byreacting the solution of LiOH with CO2 to produce a pure Li2CO3 product.Using water as the media, conventional cooling operation for chloride orsulfate salts crystallization can be omitted. For example, ammonia-driventransformation of Lithium sulfate to LiOH can be described by the reactionNH3 (g) + H2O → NH4OH(aq)Li2SO4(aq) + 2NaOH / KOH(aq) NHOH Na2SO4 / K2SO4 (s) + 2LiOH(aq)In the reaction, the crystallization / precipitation of sodium / potassium sulfatetakes place at room temperature, which is not possible in aqueous solutionwithout ammonia. After the transformation to LiOH, the second step is LiOHevaporative crystallization:NH4OH(aq) → NH3 (2) + H₂OLiOH(aq) + H₂O evaporation of NH₂-H2O →LiOH H2O(s)This is comparable to the evaporation crystallization from a water solution,however precautions are necessary to either capture ammonia for reuse,such as a cold trap or removing it from exhaust gases, e.g. by a gas washer.The reaction happens at about ambient temperature and about ambientpressure (1014 hPa) in a short time.In general, Ammonia solution or ammonia water can contain up to 25%ammonia and could be used as well, but the addition of 25% ammonia solu-tion will still cause dilution of sulfate solution and the yield of sodium / po-tassium sulfate crystallization will be limited, which makes this approachless suitable.A suitable approach was found to be is injecting gaseous ammonia into thesolution directly, preferably until saturation (~270 g / L NH3 in aqueous solu-tion).Ammonia in the sulfate solution can also be recovered by distillation and itis a non-flammable gas. Ammonia can also be used for lithium sulfatetransformation to LiOH using the similar principle.Due to the use of water as the solvent the lithium hydroxide LiOH will usual-ly be obtained in the form of its monohydrate, with one molecule of crystalwater, LiOH H2O. In this patent application LiOH it will often be used whenactually LiOH H2O is present, but the crystal water content might be ne-glected since the artisan will understand when anhydrous lithium hydroxideis present and when it is not. Moreover, it is generally known that lithiumhydroxide - monohydrate can be converted to lithium hydroxide by reactionwith phosphorus pentoxide.A similar transformation can also be applied for LiOH production from Li2SO4,and the alkali metal hydroxide employed can advantageously be eitherNaOH or KOH as well.Technical grade Li2CO3 or lithium nitrate ca be used as feed material be-cause LiCl or Li2SO4 in water solution can be easily obtained after it reactswith an acid. On the other hand, impurities such as Na2SO4 or NaCl in thefeed material does not affect the transformation reaction, so this method isalso useful for the separation of lithium and sodium.The ratio of alkali metal hydroxide to lithium salt is in particular from 1 to10 or from 2 to 5 of the stoichiometric amount, more specifically from 2.5to 3 of the stoichiometric amount. The concentration of the lithium salt canbe from about 0.5mol / L to about 5 mol / L, in particular 1 mol / L to about 2.5mol / L or from about 1.5 mol / L to about 2mol / L.With stoichiometric addition of alkali metal hydroxide, in particular NaOH,and Li2SO4 at 16 mol / L of ammonia, which is maximum at a pressure of 1.0bar, the alkali metal sulfate precipitation yield is 95%. The remaining con-centration of alkali metal sulfate is about 9.6 g / L. If carried out at an am-monia pressure of 3.0 bar, the alkali metal sulfate precipitation yield is97.5%.With excess addition of alkali metal hydroxide, in particular NaOH, and atan ammonia concentration of 14 mol / L the alkali metal sulfate precipitationyield is 99.5%, but at an ammonia concentration of 16 mol / L, the alkalimetal sulfate precipitation yield is 99.9%, which is a very high and selectiveprecipitation of alkali metal sulfate.It has been found that the reaction works very well with concentrations of 2mol / L Li2SO4, 5 mol / L alkali metal hydroxide (1.25 times of stoichiometricamount), at 30 °C, NH3 pressure 3.0 bar to to 19-20 mol / L NH3 in the solu-tion → 99.97% precipitation of SO4, zero loss of Li → filtration → 4 mol / LLiOH, 1 mol / L alkali metal hydroxide, 0.0006 mol / L alkali metal sulfate (toNH3 distillation and selective LiOH H2O crystallization over NaOH).The reaction also works very well with concentrations of 2 mol / L Li2SO4,5 mol / L alkali metal hydroxide (1.25 times of stoichiometric amount), at 30°C, NH3 pressure 1.0 bar to 16 mol / L NH3 in solution →99.85% precipitation of SO4, zero loss of Li → filtration → 4 mol / L LiOH, 1mol / L alkali metal hydroxide, 0.003 mol / L alkali metal sulfate (to NH3 distil-lation and selective LiOH H2O crystallization over NaOH). In particular,NaOH is employed as alkali metal hydroxide, but can be substituted withкон.In general, the order of addition is of little significance and whether thelithium salt is added to the alkali metal hydroxide or alkali metal hydroxideis added to the lithium salt is more determined by practical considerations.Practically, it was found that first dissolving both the alkali metal hydroxideand the lithium salt and then combining both solutions is a convenient ap-proach. Addition can be carried out at once, but it was found more practicalto add it in portions or continuously over time.Another feasible approach would be charging the solution of alkali metalhydroxide into a reactor, followed by addition of solid lithium salt in an ap-propriate amount.Another feasible approach would be to charge a reactor with an aqueoussolution of the lithium salt and to add solid alkali metal hydroxide, becausethe lithium salt often is obtained as an aqueous solution anyway and can beused as such.The concentration of the lithium salt can be from about 0.5mol / L to about 5mol / L, in particular 1 mol / L to about 2.5 mol / L or from about 1.5 mol / L toabout 2mol / L.Addition of the solid lithium salt or the alkali metal hydroxide can be carriedout at once, in portions or continuously over time.Consequently, it was also found practicable to employ either the alkali metalhydroxide, the lithium salt or both dissolved in water as solvent.The reaction takes place when gaseous ammonia is added to the reactor.The addition can be carried out at pressures of from 0.5 bar to 5 bar, morespecifically from 1 bar to 3 bar. At an ammonia pressure of 1.0 bar, themaximum ammonia concentration in the solution is about about 16 mol / L,and at 3.0 bar, the ammonia concentration can be up to about 19-20 mol / L.Introduction can be effected by simply pressurizing the reactor charged withboth the lithium salt and the alkali metal hydroxide, which both must be atleast partially dissolved in water. In an embodiment, the reactor will beevacuated at least once. Optionally, the evacuated reactor can be flushedwith an inert gas such as argon or nitrogen, but usually that isn't necessary.After evacuation, the reactor can be filled with ammonia and pressurized tothe pressure desired, in a specific embodiment with a pressure of about 1bar to about 3 bar of ammonia to achieve the desired concentration of am-monia. Introduction of the ammonia can also be effected submerged, that is,by introducing the gaseous ammonia into the reactor through a tube that issubmerged in the aqueous solution of the lithium salt and the alkali metalhydroxide.During the following conversion of lithium salt, in particular lithium chloride,lithium nitrate, lithium carbonate, lithium sulfate and combinations thereof,to lithium hydroxide the alkali metal hydroxide will turn into an alkali metalsalt. Most of the alkali metal salts, such as sodium or potassium chloride orsodium or potassium sulfate, will precipitate from the solution and can beremoved in a simple manner by filtration or centrifugation and decantationto obtain a solution of the desired product lithium hydroxide, more accu-rately lithium hydroxide-monohydrate (LiOH・H2O).The solvent (water) can be removed by distillation at ambient pressure or invacuum to obtain the solid lithium hydroxide-monohydrate exhibiting puri-ties of 94% to 99%, in particular 95% to 98%, or 97% to 98.5%, but puri-ties of 98.5% to 99% are common. Impurities usually are limited to thealkali metal hydroxide employed, usually potassium hydroxide or sodiumhydroxide and the lithium salt employed as well as alkali metal salt, such aspotassium sulfate or sodium sulfate, which is the byproduct of the reactionas well as ammonia.In a specific embodiment, the step of reacting the lithium salt with alkalimetal hydroxide in the presence of ammonia is followed by a subsequentstep of evaporative crystallization of lithium hydroxide. Usually, during thestep of evaporative crystallization not only the water, but also the ammoniaare removed partially or completely. More specifically, the water is removedpartially and ammonia is removed completely due to its higher vapor pres-sure under the conditions of water removal.Alternatively, a separate step for removal of ammonia can be carried out.Optionally, the lithium hydroxide can be further purified by recrystallisation,ion exchange or membrane processes, such as electrodialysis or reverseosmosis.A method that avoids dissolving the reaction product again, but which al-lows separation of the dry salts is electrostatic separation in an electric fieldor with a triboelectric method, for example such as described in EP 953003which can also be used to separate salts from each other. Furthermore, anapparatus for the triboelectric separation of purely inorganic mineral solidsin the ultrafine grain range was proposed in Powder Technology 86 (1996),41-47.Once the ammonia used in the method of making lithium hydroxide is re-moved, the lithium hydroxide can be converted to lithium carbonate in asimple manner by adding carbon dioxide.Thus, the Invention also relates to a method of making lithium carbonatecomprising the steps ofMaking lithium hydroxide by a method of any of claims 1 to 19;- removing ammonia by a suitable method, in particular by distillationand / or evaporation;reacting the lithium hydroxide with carbon dioxide to form lithiumcarbonate.In this way lithium carbonate exhibiting a particularly low amount of sodiumcan be obtained, more specifically lithium carbonate that is sodium-free.Common methods for making lithium carbonate from minerals or lithiumsalts usually comprise steps that involve precipitation with sodium car-bonate, which results in sodium contamination of the lithium carbonate thusobtained, see Martin Bertau, Armin Müller, Peter Fröhlich, Michael Katzberget al.: Industrielle Anorganische Chemie. John Wiley & Sons, 2013.Thus, this method solves the problem of providing lithium carbonate that isfree of sodium or at least has a low sodium content.The step of reacting the lithium hydroxide with carbon dioxide to form lithi-um carbonate can be carried out by simple addition of carbon dioxide tolithium hydroxide, which preferably is dissolved.Addition of the carbon dioxide can be carried out by known methods, suchas passing a stream of carbon dioxide over the surface, in particular thesurface of a solution or suspension of lithium carbonate, or carbon dioxidemight be passed through a solution via a submerged nozzle or tube, or thesolution or suspension of lithium hydroxide is pressurized with carbon diox-ide.The lithium carbonate obtained according to the invention can be isolatedand optionally further purified with known methods, e.g. by recrystallisation.For this purpose, or as an alternative way of purification, the lithium car-bonate is further reacted with carbon dioxide to obtain metastable lithiumhydrogen carbonate (lithium bicarbonate). After precipitation of impurities,the lithium hydrogen carbonate then can be collected and converted backinto pure lithium carbonate by heating to 95 °C, see Donald E. Gar-rett: Handbook of Lithium and Natural Calcium Chloride. Academic Press,2004.The lithium salts employed in the method of making lithium hydroxide (or,in a subsequent step, can be converted into lithium carbonate) from lithiumsalts can, in particular, be obtained from natural sources such as lithiumores or deposits and may be pre-processed and / or converted to lithiumsalts that are consequently used in the method described herein. Such oresare, for example, spodumene or pegmatite.If ammonia is not removed or some ammonia remains after distillation, thereaction of the lithium hydroxide to lithium carbonate with carbon dioxidecan be carried out nonetheless. It is to be expected that to a certain extentammonium carbonate is being generated, though. Due to its significantlyhigher solubility in water than lithium carbonate, separation of lithium car-bonate from ammonium carbonate can be easily accomplished.Consequently, the invention also relates to to a method of making lithiumcarbonate comprising the steps ofMaking lithium hydroxide by a method of the invention as disclosedabove;reacting the lithium hydroxide with carbon dioxide to form lithiumcarbonate.If necessary, a subsequent purification step to separate lithium carbonateand ammonium carbonate can be carried out, such as filtering of precipitat-ed lithium carbonate from an ammonium carbonate solution.The lithium salt can also be obtained by recycling of lithium-ion batteries, inparticular from a process disclosed in WO 2022 / 248436, which is a processfor the recovery of valuable metals from a metallurgical charge comprisingslag formers, and Li-ion batteries or their derived products containing Co, Ni,metallic Al, and C, comprising the steps of:- providing a metallurgical smelting furnace equipped with means for thesubmerged injection of an O2-bearing gas;defining an oxidizing level Ox characterizing oxidizing smelting conditionsaccording to the formula:Ox = pCO2 / (pCO+pCO2),wherein 0.1 < Ox < 1, pCO and pCO2 are the partial pressures of CO andCO2 in contact with the melt;preparing the metallurgical charge comprising a weight fraction Bf of Li-ionbatteries or their derived products, according to the formula:1 > Bf > 0,3 / ((1 + 3.5 * Ox) * C) + 2.5 * Al),wherein Ox is the oxidizing level, and Al and C are the weight fractions ofrespectively metallic Al and C in said batteries or their derived products;oxidizing smelting the metallurgical charge by injecting an O2-bearing gasinto the melt to reach the defined oxidizing level Ox, thereby obtaining afirst alloy with a major part of Ni, and a first slag containing residual Ni andCo;liquid / liquid separation of the first alloy from the first slag; and,- reducing smelting of the first slag using a heat source and a reducingagent, maintaining a reduction potential ensuring the reduction of Co and Ni,thereby producing a second alloy, and a second slag containing less than1% by weight of Ni, preferably less than 0.5%, and more preferably lessthan 0.1%.In such processes, the lithium salts can be dissolved in solutions with saltsof other metals, in particular nickel, cobalt, manganese, iron, aluminum andpossibly other metals.The lithium can be also obtained when the Lithium is removed and / orconcentrated during a process for recycling of rechargeable batteries orparts thereof. Such a method is, for example, disclosed in WO 2021 / 104164.Such a process is a process for the concentration of lithium in metallurgicalfumes is described, comprising the steps of:- providing a metallurgical molten bath furnace;- preparing a metallurgical charge comprising lithium-bearing material,transition metals, and fluxing agents;smelting the metallurgical charge and fluxing agents in reducing condi-tions in said furnace, thereby obtaining a molten bath with an alloy and aslag phase; and,optionally separating the alloy and the slag phase;characterized in that a major part of the lithium is fumed as LiCl from themolten slag, by addition of alkali and / or earth alkali chloride, chlorine, hy-drogen chloride or a combination thereof to the process.Consequently, the invention also relates to a process for the recovery ofvaluable metals from rechargeable batteries containing lithium compounds,whereinthe lithium compounds are converted to lithium salts, andreacting the lithium salts to lithium hydroxide with the method ofmaking lithium hydroxide from lithium salts by reacting a lithium saltwith an alkali metal hydroxide, wherein the alkali metal hydroxide isan alkali metal hydroxide other than lithium hydroxide in aqueous so-lution, wherein gaseous ammonia is added.In a specific embodiment, in the process for the recovery of valuable metalsfrom rechargeable batteries containing lithium compounds, the step of thelithium compounds being converted to lithium salts comprises the concen-tration of lithium in metallurgical fumes comprising the steps of:- providing a metallurgical molten bath furnace;preparing a metallurgical charge comprising lithium-bearing material,transition metals, and fluxing agents;smelting the metallurgical charge and fluxing agents in reducing condi-tions in said furnace, thereby obtaining a molten bath with an alloy and aslag phase; and,- optionally separating the alloy and the slag phase;characterized in that a major part of the lithium is fumed as LiCl from themolten slag, by addition of alkali and / or earth alkali chloride, chlorine, hy-drogen chloride or a combination thereof to the process.The Invention is further illustrated with the following examples.Examples:Example 1NH3 (g) + H2O → NH4OH(aq)Li2SO4NH4OH04(aq) + 2NaOll 2NaOll(aq) → Na2SO4 04(s) + 2LIOII (aq)NH4OH(aq) NH3 (g)I H₂OLiOH(aq) + H2O evaporation of NH3 -H2O →LiOH H2O(s)1. Dissolving 150 g NaOH in 500 ml water to get 7.5 mol / L NaOH solu-tion.2. Dissolving 165 g Li2SO4 in 500 ml water to get 3 mol / LLi2SO4 solution.3. At room temperature, mixing solution A and solution B (Note: aftermixing, 1.5 mol / L Li2SO4 and 3.75 mol / L NaOH solution is obtained,we can also use Li2SO4.H2O and add solid Li2SO4.H2O in 3.75 mol / LNaOH solution until 1.5 mol / L Li2SO4 or add solid NaOH in 1.5 mol / LLi2SO4 solution until 3.75 mol / L NaOH or even add concentratedNaOH, like 50% (12.5 mol / L) NaOH in ~2.14 mol / L Li2SO4 solution)4. Injecting NH3 gas into the solution at pressure 1.0 bar and 30 °C un-til 16 mol / L (272 g / L) NH3 dissolved in the solution and selectiveNa2SO4 crystallization will happen.5. The precipitation yield of SO4 is 99.8% and the resulting Na2SO4 pre-cipitate contained 99% Na2SO4, others are Li2SO4 (0.5%) and LiOH(0.5%). After washing the Na2SO4 will contain >99.5% Na2SO4, theloss of Li is about 0.2 %. The mother liquor after Na2SO4 precipitationcontains 72 g / L LiOH, 30.3 g / L NaOH, 0.8 g / L Na2SO4.6. Evaporation of the solvent to get LiOH crystals, temperature from 45°C (boiling point at 16 mol / L NH3) to 100 °C, can also be done at alower temperature under vacuum. NH3 will be distilled first and re-turned to step 4. The evaporative crystallization is finished at a con-centration factor at around 10. The mother liquor contains ~300 g / LNaOH, ~61 g / L LiOH, ~8 g / L Na2SO4. This mother liquor should bereturned to step 3.7. The resulting LiOH H2O contains 98.5% LiOH H2O and 0.5% Na2SO4and 1% NaOH. At this step the LiOH crystallization yield is about86.1%.8. Recrystallization of LiOH in water solution will get a TG-LIOH H2O.Example 2NH3 (g) + H2O → NH4OH(aq)NHOHLi2SO4(aq) + 2NaOH(aq) → Na2SO4 (s) + 2LiOH(aq)NH4OH(aq) → NH3 (g) + H2OLiOH(aq) + H2O evaporation of NH₂-H2O 4(s) LIOH H2O(s)1. In the hydrometallurgical processing of spent LFP battery, Li2SO4 so-lution containing 17 g / L Li, 13 g / L Na and a small amount of impuri-ties, like Ni, Co, F, Si, P, < 500 ppm in total can be obtained. It isequal to 1.2 mol / L Li2SO4 and 0.3 mol / L Na2SO4.2. Adding 120g solid NaOH in 1.0 L of the 17 g / L Li, 13 g / L Na sulfatesolution, and injecting NH3 to 19 mol / L at a NH3 pressure 3.0 bar.Na2SO4 crystallization happens and the SO4 precipitation yield is99.97%. (Note: at 1.0 bar of NH3, the maximum NH3 concentrationin the solution is about 16 mol / L, and at 3.0 bar, the NH3 concentra-tion can be up to 19-20 mol / L.)3. The resulting Na2SO4 precipitate contained 99.2% Na2SO4, othersare Li2SO4 (0.3%) and LiOH (0.5%). After washing the Na2SO4 willcontain >99.5% Na2SO4, the loss of Li is about 0.2%. The motherliquor after Na2SO4 precipitation contains 57.5 g / L LiOH, 24 g / LNaOH, 0.1 g / L Na2SO4.4. Evaporation of the solvent to get LiOH crystals, temperature from 45°C (boiling point at 16 mol / L NH3) to 100 °C, can also be done at alower temperature under vacuum. NH3 will be distilled first and re-turned to step 4. The evaporative crystallization is finished at a con-centration factor at around 10. The mother liquor contains ~240 g / LNaOH, ~56 g / L LiOH, ~1 g / L Na2SO4. This mother liquor should bereturned to the previous steps in LFP recycling, such as hydrolysis ofimpurities. At this step the LiOH crystallization yield is about 90.3%.5. The resulting LiOH H2 contains 99.0% LiOH H2O and 0.2% Na2SO4and 0.8% NaOH.6. Recrystallization of LiOH in water solution will get a TG-LIOH H2O.Example 3NH3 (g) + H2O → NH4OH(aq)→ Na2SO4 04(s) + 2LiOH(aq)NH, OHLi2SO4 (aq) + 2NaOH(aq)NH4OH(aq) → NH3 (g) + H₂O2LIOH(aq) + CO₂→ Li2CO3(s) + H2O1. In the hydrometallurgical processing of NMC industrial black mass,Li2SO4 solution containing 23 g / L Li, 5 g / L H2SO4 and a small amountof impurities, like Ni, Co, F, Si, P, < 100 ppm in total can be obtainedafter a solvent extraction process. It is equal to 1.6 mol / L Li2SO4 and0.1 mol / L H2SO4.2. Adding 132 g solid NaOH in 1.0 L of the 17 g / L Li, 5 g / L H2SO4 solu-tion, and injecting NH3 to 17 mol / L at a NH3 pressure 2.0 bar.Na2SO4 crystallization happens and the SO4 precipitation yield is95.5%.3. The resulting Na2SO4 precipitate contained 99.3% Na2SO4, othersare Li2SO4 (0.2%) and LiOH (0.5%). After washing the Na2SO4 willcontain >99.5% Na2SO4, the loss of Li is about 0.2%. The motherliquor after Na2SO4 precipitation contains 78.7 g / L LiOH, 12.1 g / LNa2SO4.4. Distillation to remove ammonia, 90% NH3 can be removed by distilla-tion at 100 °C and resulting in a solution containing 120 g / L LiOH,18.4 g / L Na2SO4. Thereafter, the Li-rich resultant liquor was furtherused to recover the Li by bubbling 7 mol of CO2 gas at 0.068 mol(CO2) / L.min and 40 °C. The Li2CO3 precipitates were separated fromthe suspension through filtration followed by washing using hot waterand hot air drying. Through this precipitation step, 85% of Li can berecovered in the form of Li2CO3.5. The resulting Li2CO3 contains > 99.5% Li2CO3, which is a technical-grade product.

Claims

Claims1. Method of making lithium hydroxide from lithium salts by reacting alithium salt with an alkali metal hydroxide, wherein the alkali metalhydroxide is an alkali metal hydroxide other than lithium hydroxide inaqueous solution, wherein gaseous ammonia is added.

2. Method of claim 1, wherein the lithium salt is a lithium halide.

3. Method of claim 1 or 2, wherein the lithium salt is selected from thegroup consisting of lithium chloride, lithium nitrate, lithium carbonate,lithium sulfate and combinations thereof.

4. Method of any of claims 1 to 3, wherein the reaction is carried out at areaction temperature from about 10°C to about 70°C, or from 20°C toabout 50°C or from about 25°C to about 45°C.

5. Method of any of claims 1 to 4, wherein the reaction time is from 15minutes to 15 hours, or 30 minutes to 6 hours, or from 40 minutes to1 hour.

6. Method of any of claims 1 to 5, wherein the alkali metal hydroxide isselected from a hydroxide of an alkali metal selected from the groupconsisting of sodium, potassium, rubidium, cesium and combinationsthereof, or sodium, potassium and combinations thereof.

7. Method of any of claims 1 to 6, wherein the gaseous ammonia is addedat pressures of from 0.5 bar to 5 bar, more specifically from 1 bar to 3bar.

8. Method of any of claims 1 to 7, wherein the concentration of the lithi-um salt is from about 0.5mol / L to about 5 mol / L, in particular 1 mol / Lto about 2.5 mol / L or from about 1.5 mol / L to about 2 mol / L.

9. Method of any of claims 1 to 8, wherein the ratio of alkali metal hy-droxide to lithium salt is from 2 to 5 or 2.5 to 3 of the stoichiometricamount.

10. Method of any of claims 1 to 9, wherein either the alkali metal hydrox-ide, the lithium salt or both are employed dissolved in a solvent.

11. Method of any of claims 1 to 10, wherein the alkali metal hydroxide isdissolved in water, the aqueous solution of the alkali metal hydroxideis charged into a reactor and the solid lithium salt is added to theaqueous solution of the alkali metal hydroxide either at once, in por-tions or continuously.

12. Method of any of claims 1 to 10, wherein an aqueous solution of thelithium salt is charged into a reactor and the alkali metal hydroxide is-added to the aqueous solution of the lithium salt either as a solid, asan aqueous solution or a combination thereof either at once, in por-tions or continuously.

13. Method of any of claims 1 to 10, wherein both the alkali metal hydrox-ide as well as the lithium salt are dissolved in water and are combinedeither at once, in portions or continuously.

14. Method of any of claims 1 to 13, wherein the step of reacting the lithi-um salt with alkali metal hydroxide in the presence of ammonia is fol-lowed by a subsequent step of evaporative crystallization of lithiumhydroxide.

15. Method of any of claims 1 to 14, wherein the maximum ammonia con-centration in the aqueous solution is from about 16 mol / L to about 20mol / L.

16. Method of any of claims 1 to 15, wherein the method further comprisesa filtration step.

17. Method of any of claims 1 to 16, wherein the method further comprisesa recrystallisation step.

18. Method of making lithium hydroxide from lithium salts by reacting alithium salt with an alkali metal hydroxide of any of claims 1 to 17,wherein the alkali metal hydroxide is an alkali metal hydroxide otherthan lithium hydroxide, further comprising the steps of -reacting thelithium salt with alkali metal hydroxide wherein gaseous ammonia isadded; -in a subsequent step, filtration to remove insoluble byproductsand other impurities; -evaporative crystallization of lithium hydroxideby partially or completely removing of the water and ammonia; -optionally further purifying the lithium hydroxide obtained.

19. Method of any of claims 1 to 18, wherein the lithium hydroxide ob-tained by said method is further purified by a method selected fromthe group consisting of recrystallisation, ion exchange, electrodialysis,reverse osmosis, electrostatic separation, a triboelectric method orcombinations thereof.

20. Method of making lithium carbonate comprising the steps -Makinglithium hydroxide by a method of any of claims 1 to 19-reacting thelithium hydroxide with carbon dioxide to form lithium carbonate.

21. Method of making lithium carbonate according to claim 20, comprisingthe steps -Making lithium hydroxide by a method of any of claims 1 to19; -removing ammonia by a suitable method; -reacting the lithiumhydroxide with carbon dioxide to form lithium carbonate.

22. Method of claim 20 or 21, wherein the lithium carbonate is isolated andoptionally further purified.

23. A process for the recovery of valuable metals from rechargeable bat-teries containing lithium compounds, wherein -the lithium compoundsare converted to lithium salts, and -reacting the lithium salts to lithiumhydroxide with the method of any of claims 1 to 19.

24. A process for the recovery of valuable metals from rechargeable bat-teries containing lithium compounds of claim 23, wherein the lithiumcompounds are converted to lithium salts comprises the steps of:providing a metallurgical molten bath furnace;preparing a metallurgical charge comprising lithium-bearing mate-rial, transition metals, and fluxing agents;smelting the metallurgical charge and fluxing agents in reducingconditions in said furnace, thereby obtaining a molten bath with analloy and a slag phase; and,optionally separating the alloy and the slag phase;characterized in that a major part of the lithium is fumed as LiClfrom the molten slag, by addition of alkali and / or earth alkali chlo-ride, chlorine, hydrogen chloride or a combination thereof to theprocess.

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