TECHNICAL FIELD

[0001] The present invention relates broadly to a method of mineral carbonation by heating a powder of a porous mineral P-spodumene in a rector at about 450-600°C in a gas containing CO2 to form lithium carbonate in the powder particle mineral, which is then extracted from the particle at low temperatures and pressures in aqueous solutions to produce lithium carbonate or other desirable lithium salts.

[0002] The invention may be applied as an additional pyroprocessing step in the processing of lithium containing mineral precursors, such as a-spodumene, eucryptite, petalite, bikitaite, or zinnwaldite at a temperature of about 900°C to produce the porous P-spodumene.

[0003] The invention describes a flow sheet for transforming a lithium mineral precursor to lithium carbonate and lithium aluminium silicate using a CO2 gas stream in a mineral carbonation process.

BACKGROUND

[0004] Lithium carbonate is the preferred source of lithium for the production of lithium batteries because, as a powder, it is more readily transported that either lithium hydroxide or lithium oxide because it does not adsorb moisture, and it is readily intercalated into anode and cathode materials.

[0005] This growth of battery markets is to be sustained by ongoing reductions in the cost of input materials, including the cost of lithium carbonate. There are several sources of lithium that are used, namely from salar brines in which the lithium has been concentrated over long periods of time, and from a range of minerals which contain 2-6 wt% of lithium, including a-spodumene, eucryptite, petalite, bikitaite, and zinnwaldite as described by Dessemond et.al in “Spodumene: The Lithium Market, Resources and Processes” Minerals, 9, 334 (2019). The invention disclosed herein describes a novel means of extraction of lithium from such minerals. [0006] These minerals are generally comprised of the oxides of lithium, aluminium and silica and a preferably beneficiated at a minesite by grinding and floatation to remove gangue and to produce a powder. A pyroprocessing stage is generally used to transform the mineral powder to low density [3-spodumene, LiAlSi2Oe which opens up pores throughout the mineral. This stage is generally a phase change, and is carried out in a reactor at about 900°C. For the purposes of this disclosure, the pyroprocessed mineral is called P-spodumene, even though the low density phase is found in a mixture of compounds depending on the composition of the input mineral, and may also include other low density phases such as y-spodumene. Generally, the dense raw mineral is impervious to liquids, such that the lithium extraction processes described below are too slow.

[0007] The traditional pyroprocessing stage to produce such P-spodumene uses a rotary kiln in which the heat to raise the temperature to that of the phase transition comes from combustion of fossil fuels within the reactor, so the pyroprocess occurs in a gas of hot nitrogen, carbon dioxide and steam and the P-spodumene powder is separated from the gas at about 900°C. Another approach is to used fluidised beds, as described by Gasafi and Pardemann in “Processing of spodumene concentrates in fluidised bed systems”, Minerals Engineering, 148, 106205 (2020) in which the fluidised bed is supported by the flow of a combustion gas. More recently, the Sceats et. al., in the patent application PCT/AU2021/050807 for an "A Method for the Pyroprocessing of Powders” (incorporated herein by reference), describes an indirectly heated calciner for this pyroprocessing stage. In that process, the material is finely ground so the residence time of the particles is less than about 30 seconds which has the benefit that the melting of silica over the surface of the particle, which is observed in kiln processing, and which inhibits the subsequent process for extraction of lithium, is suppressed. That invention may use renewable electric power for provision of heat. In the context of the invention disclosed herein, the gas used inside such an indirectly heated reactor is not required to be specified. [0008] In the context of extraction of lithium from [3-spodumene powder, the traditional processes are to first roast the P-spodumene in concentrated sulphuric acid at about 200°C to produce lithium sulphate, and then complete the extraction at lower temperatures in water using the high water solubility of lithium sulphate, Li2SO4 in an aqueous solution water by precipitation of lithium carbonate Li2CO3 using soda-ash to supply the carbonate. By reference, the solubility of Li2SO4 and Li2CO3 in water at 30°C are 34.8 and 1.3 g/100 ml. There are a range of similar processes using acids such as nitric acid, hydrochloric acid to breakdown the mineral structure of P-spodumene and create a water soluble salt. However, the sulphuric acid roasting and aqueous solution extraction and precipitation, develop and optimised over many years is the preferred dominant route.

[0009] Another means of extraction of lithium from is known that roasting of limestone CaCCh and spodumene at high temperature can be used to form Li2O at high temperatures by breaking down the structure of the a-spodumene for extraction of lithium through the formation of calcium aluminosilicates.

[0010] The high cost of the materials to extract the lithium has led to a number of other approaches. One such approach that is relevant to this disclosure is the use of supercritical or near super critical carbon dioxide and water to form Li2CO3 as disclosed by Correa in US patent 9,028,789 “Process to produce lithium carbonate directly from the aluminosilicate mineral”. That patent discloses that extraction of lithium could be efficiently extracted from particles of 50 pm diameter with water and carbon dioxide at a pressure of 30 to 50 bar and temperature of 150 to 180° C in several hours through the formation and extraction of lithium bicarbonate Li HCCh from the mineral. The lithium bicarbonate is soluble in the high pressure CCh/water fluid. The benefit of this process is that the high pressure CCh/water can be recycled, with a makeup, so that in contrast with the sulphuric acid process less water is used, and corrosive sulphur gases released in the high temperature roasting processes are eliminated. The rate of reaction was observed to increase with temperature, and the temperature limit of 150-180°C was determined by physical limitations of operating a plant at 30-50 bar pressure. They noted that this extraction process did not destroy the aluminosilica matrix, so the residual particles could be used as additives for ceramics.

[0011] In laboratory tests, Korake and Gai wad in “Capture of carbon dioxide over porous adsorbents of lithium silicate, lithium aluminate and magnesium aluminates at pre-combustion temperatures” Front. Chem. Eng. China, DOI 10.1007/sl 1705-010- 1012 (2010) showed that a broad range of porous synthetic lithium aluminium and lithium silicates could absorb CO2 at temperatures in the range of 400-700°C at CO2 pressures of several atmospheres, and that doping of the materials with alkali metals enhanced the reaction.

[0012] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

SUMMARY

[0013] PROBLEMS TO BE SOLVED

[0014] The problem to be solved is the development of a method of extraction of lithium from P-spodumene. It will be apparent to a person skilled in the art that the invention of this disclosure is preferably linked to the pyroprocess described by Sceats et. al. to produce P-spodumene from a-spodumene and a range of other lithium containing minerals.

[0015] The desirable attributes of such an extraction method are to (a) to be thermally efficient when integrated with the production of P-spodumene from a lithium bearing mineral ; (b) eliminate the need for large volumes of water; (c) eliminating highly reactive acids as used in the conventional process, and (d) eliminating the for high pressure CCWwater fluids as described in the patent of Correa. [0016] There is a need to produce high-grade lithium carbonate at a site where the lithium carbonate is first processed in order to simplify, and lower the costs of lithium battery production.

[0017] There is a need to reduce the CO2 emissions intensity of the production of lithium batteries, and that need may be filled in part by minimising the CO2 emissions from the production of battery input materials, such a lithium carbonate.

[0018] The invention described herein may address at least one of the aforementioned problems that arise in the extraction of lithium from minerals.

[0019] MEANS FOR SOLVING THE PROBLEM

[0020] In a first aspect of the present disclosure, a device for producing carbonated 0- spodumene, the device may comprise: a carboniser reactor having a powder inlet and a powder outlet, wherein the powder inlet is adapted to receive 0-spodumene powder, and the powder outlet allows for carbonated 0-spodumene to exit the carboniser reactor; the carboniser reactor in fluid communication with a first gas inlet and a first gas outlet, wherein the first gas inlet is distal to the powder inlet, and wherein the first gas outlet is distal to the powder outlet; wherein the gas comprises carbon dioxide and water; an external heat transfer segment in thermal communication with the carboniser reactor wherein the segment is adapted to maintain a temperature in the carboniser reactor in the range between 400°C to 600°C.

[0021] Preferably, the device further comprises a phase change reactor having a second powder inlet and a second powder outlet, wherein the second powder outlet is in fluid communication with the powder inlet of the carboniser reactor, wherein the second powder inlet is adapted to receive a-spodumene powder; the phase change reactor in fluid communication with a second gas inlet and a second gas outlet, wherein the first gas outlet is in fluid communication with the second gas inlet; a second external heat transfer segment in thermal communication with the phase change reactor, wherein the second external heat transfer segment is adapted to maintain a temperature in the phase change reactor in the range between 800°C to 1000°C.

[0022] Preferably, the device further comprises a first filter for filtering the powder from the gas prior to entering the first gas outlet.

[0023] Preferably, the device further comprises a second filter for filtering the powder from the gas prior to entering the second gas outlet.

[0024] Preferably, the device is adapted to produce lithium carbonate powder from carbonated [3-spodumene, the device further comprising: a bicarboniser reactor and a precipitator segment each having an inlet and and an outlet, wherein the bicarboniser reactor is positioned between the carboniser reactor and the precipitator segment, wherein the inlet of the bicarboniser reactor is in connection with the powder outlet of the carboniser reactor, and wherein the outlet of the bicarboniser reactor is in connection with the inlet of the precipitator segment.

[0025] Preferably, the bicarboniser reactor comprises a third gas inlet, a water inlet, and a third gas outlet, wherein the bicarboniser reactor is in fluid communication with the third gas inlet, the water inlet and the third gas outlet, wherein the third gas inlet is for injecting carbon dioxide into an aqueous slurry of carbonated [3- spodumene, wherein excess carbon dioxide and steam enters the third gas outlet.

[0026] Preferably, the bicarboniser reactor comprises a heat exchanger for maintaining the reactor at near an ambient temperature.

[0027] Preferably, a solid filter for filtering aluminosilicate solids from the aqueous slurry is positioned between the outlet of the bicarbonate reactor and the inlet of the precipitator segment.

[0028] Preferably, the inlet of the precipitator segment is adapted to receive lithium bicarbonate solution from the filtration of the aqueous slurry. [0029] Preferably, the precipitator segment comprises a heat transfer segment for heating the lithium bicarbonate solution to a temperature between the range of 85 to 95°C.

[0030] Preferably, the precipitator segment has a fourth gas outlet, wherein the carbon dioxide emitted from the heated solution is reinjected to the third gas inlet of the bicarboniser reactor.

[0031] Preferably, the precipitator segment further comprising a second solid filter for collecting wet lithium carbonate.

[0032] Preferably, the device further comprises a drying station for drying the wet lithium carbonate from the second filter.

[0033] Preferably, the device further comprising a carbon dioxide generator which is in fluid communication with the third gas inlet of the bicarbonator reactor.

[0034] the device further comprising an extraction station, wherein the extraction station is adapted for extracting lithium from dried lithium carbonate using a weak acidic solution selected from the group of: acetic acid, and oxalic acid.

[0035] In a second aspect of the present disclosure, a process to extract lithium from [3- spodumene or alkali activated P-spodumene particles is a first step of forming weakly bound lithium carbonate (Li2CO3) at a temperature of 400-650°C in a carbonising reactor at about 1 bar total pressure of CO2 and steam; and cooling the particles to a temperature to form a slurry where the lithium salt can be dissolved from the particle for example, by sparging the slurry in CO2 to form soluble lithium bicarbonate, filtering the solution to remove the aluminosilicate powder, heating the bicarbonate solution to about 90°C to liberate the CO2 to form precipitated Li2CO3, which is filtered. The purity of the Lithium Carbonate crystals may be enhanced by CO2 sparging of the lithium carbonate product until it dissolves, and re-precipitation by heating, and the process is repeated to purify the Li2CC>3 to make a high grade Li2CC>3 product. [0036] In a third aspect of the present disclosure, the process of the first aspect may be integrated into the production of P-spodumene by pyroprocessing a lithium mineral, in say CO2 and steam at about 1 bar and 900°C, and then reducing the temperature to about 400-650°C to enable the carbonation of the lithium within the particle. The heat liberated from the cooling of the particle and gas streams may be used to provide the heat for the precipitation processes described in the first aspect. In this aspect, the energy used for the pyroprocessing is renewable power.

[0037] Preferably, the method and process for extraction of lithium from a porous powder containing lithium, in which the powder contains lithium in the range of 2- 8% by weight of Li2O, by carbonising the powder in a CCh/steam gas where (a) the pressure of the gas stream is desirably in the range of 1 bar, and (b) the steam content of the gas steam is desirably about 10%; and (c) the particle size is less than about 200 pm; and (d) the reactor temperature is in the range of 450-600°C; and the lithium is preferably extracted from the carbonised particles using aqueous solutions.

[0038] Preferably, the porous power is produced from minerals that include a- spodumene, eucryptite, petalite, bikitaite, or zinnwaldite by first pyroprocessing the mineral at about 900-1000°C to produce a reactive material such as P-spodumene.

[0039] Preferably, the production of the porous powder is preferably by use of indirect heating of the pyroprocessor preferably using renewable power.

[0040] Preferably, the pyroprocessing is catalysed in a gas of CO2 and steam.

[0041] Preferably, the lithium is extracted from the carbonated powder using weak acids such as acetic acid or oxalic acid.

[0042] Preferably, the lithium is extracted from the carbonated powder using: (a) sparging of CO2 into an aqueous slurry of the carbonated powder at near ambient temperature to form a soluble lithium bicarbonate solution, and filtering the solid residue from the solution; and (b) heating the lithium bicarbonate solution to about 90°C to precipitate the lithium carbonate and liberate CO2; and (c) filtering and drying the lithium carbonate product. More preferably, the process of (a) to (c) is repeated at least once to maximise the purity of the lithium carbonate product.

[0043] Preferably, the CO2 liberated is recycled between reactors/segments so the demand of CO2 is minimised.

[0044] Preferably, the water and steam is recycled between reactors/segments so the demand for both water and steam is minimised.

[0045] Preferably, the waste energy from the pyroprocessor is consumed for heating and cooling and vaporising processes so that any additional energy demands are minimised.

[0046] Preferably, the CO2 gas required to make the lithium carbonate is generated as a pure gas steam in an indirectly heated calciner to process ground limestone, or dolomite or magnesite or mixtures of these minerals, so that the powder product from this calcination process is low or zero emissions lime, dolime or magnesia.

[0047] Preferably, the excess energy from the calciner is used to minimise the energy demand of the overall process of production of the lithium carbonate, and the lime, or dolime or magnesia products.

[0048] In the three aspects, the only chemical consumed to make the Li2CO3 product from the mineral inputs is CO2 and H2O. Such a process maybe carried out as part of CO2 capture system to limit global warming, and is characterised as a Carbon Capture and Use (CCU) process. The energy efficiency of the process can be minimised by reuse of the heat from the pyroprocessing streams for production of the Li2CO3 product.

[0049] In a fourth aspect of the present invention, the production of CO2 may be accomplished by calcining a limestone, dolomite or magnesite in an externally heated reactor using renewable power to produce the CO2 required in the aforementioned aspects and to make zero emissions lime, dolime or magnesia for other uses. In this aspect, the production of these products and Li2CO3 is a zero emissions process,

BRIEF DESCRIPTION OF THE FIGURES

[0050] Embodiments of the invention will be better understood and readily apparent to one of ordinary skill in the art from the following written description, by way of example only, and in conjunction with the drawings.

[0051 ] The embodiment of Figure 1 illustrates a schematic of a reactor system in which an externally heated vessel is used to processes [3-spodumene particles in a CO2 steam mixture to form lithium carbonate in the particles.

[0052] The embodiment of Figure 2 illustrates a schematic of a reactor system in which an externally heated vessel is used to processes a-spodumene particles in a CO2 steam mixture to form [3-spodumene particles in a first stage and to form lithium carbonate in the particles in a second stage.

[0053] The embodiment of Figure 3 illustrates a process flow in which an externally heated reactor is used to process a-spodumene particles in a CO2 steam mixture to form [3-spodumene particles in a first stage, and to form lithium carbonate in the particles in a second stage at a lower temperature, and the lithium carbonate is extracted from the particles by sparging a slurry of particles with CO2 in a third stage to form soluble lithium bicarbonate, filtering the aluminosilicate particles, and heating the liquid containing lithium bicarbonate in a fourth stage to release CO2 and form insoluble Ei2CC>3, which is filtered from the liquid.

[0054] The embodiment of Figure 4 illustrates a process flow in which an externally heated reactor is used to process limestone to lime and CO2 in a first stage, and an externally heated reactor is used in a second stage to process a-spodumene particles in a CO2 from the first reactor and steam to form [3-spodumene particles, and to form lithium carbonate in the particles in a third stage at a lower temperature, and the lithium carbonate is extracted from the particles in a fourth stage by sparging a slurry of particles with CO2 to form soluble lithium bicarbonate, filtering the aluminosilicate particles, and heating the liquid containing lithium bicarbonate in a fifth stage to release CO2 and form insoluble Li2COs, which is filtered from the liquid.

DESCRIPTION OF THE INVENTION

[0055] Preferred embodiments of the invention will now be described by reference to the accompanying drawings and non-limiting examples.

[0056] The indirectly heated pyroprocessor/calciner reactors described herein are adaptations of the indirect heated calciner described by Horley and Sceats in

W02007112496 “System and Method of Calcination of Minerals” and references therein (incorporated herein by reference), and further developed Sceats et al. in

WO20 18076073 “A flash calciner” and references therein (incorporated herein by reference). In the case of pyroporcessing of lithium minerals to make P-spodumene the reactor is that described by Sceats et. al. in the patent application PCT/AU2021/050807. The advantages of using these reactors with renewable power is that the residence time of the particles is the order of 30 seconds, so that the reactors can be ramped, and turned off quickly and when maintained at near the operating temperature with a small amount of energy, such as from a combustor of biomass, to offset radiation losses, the reactors can be turned on quickly so that the cost of production can be minimised by scaling to the diurnal availability of renewable power.

[0057] The example embodiments refer to the processing of spodumene, which is one example of the application of this invention for a range of minerals with high lithium content.

[0058] In consideration of the first aspect of the present invention, the example embodiment of Figure 1 illustrates that a carboniser reactor 101 is used process a feed of P-spodumene powder 102 and CO2.H2O gas 103 to make a product 104 of carbonated P- spodumene. The powder feed 102 is injected into the reactor using a rotary valve 105 and the temperature of the reactor is regulated by the external heat transfer system 106 so that the carbonation reaction takes place at about 500°C. The CO2 depleted CO2/H2O stream 107 is ejected from the reactor after the particles are removed from the gas stream by the particle-gas separation system 108. The carbonated powder is collected in the cone 108 and is elected from the reactor by the rotary valve 110. A portion of the CO2/H2O stream may be pressurised and injected into the powder bed to complete the carbonation reaction, or the reactor is operated as a circulating fluidised bed to achieve the desired degree of carbonation. These option apply to the other example embodiments for the carboniser reactor described below.

[0059] In consideration of the second invention to illustrate the integration of the carboniser with a production process of P-spodumene, the example embodiment of Figure 2 illustrates a segmented reactor comprising a phase change reactor segment 201 and a carboniser reactor segment 202 are used to process a feed of a a-spodumene powder 203 and a CO2/H2O gas 204 to produce a carbonated P-spodumene powder 205 and a CO2 depleted CO2/H2O gas stream 206. The feed 203 is injected into the reactor by a rotary valve 207 and is heated to a temperature of about 900oC using an external heater 208 to induce the phase change from dense a-spodumene to low density porous P-spodumene. The CO2 depleted CO2/H2O gas stream 209 is injected from the carbonator reactor 202 through the gas transfer system 210 and is used to catalyse this phase change, and is exhausted from the reactor as the stream 206 after any particles are removed by the particle-gas stream separator 211. The P-spodumene powder is collected in the reactor cone 212 and is injected into the carboniser reactor 202 using a valve 213 as the powder stream 214. In the carboniser reactor the P-spodumene powder 214 is converted to the carbonated P-spodumene product 205 by the reaction with the injected CO2/H2O gas 204 at a temperature of about 500°C, which is regulated by the cooling/heating system 215. The carbonated powder is collected in the cone 216 and is ejected from reactor using a rotary valve 217 as the carbonated P-spodumene product 205. [0060] The means of production of lithium carbonate from the carbonated P-spodumene product of the embodiments of Figure 2 is illustrated in the process flow embodiment of Figure 3. The process flow of Figure 3 shows how a steam of a-spodumene 301 is processed with a CO2 steam 302 to make a product of lithium carbonate 303 and alumininosilicate 304 in a four stage process. In Stage 1 , a calciner reactor is used to convert the a-spodumene 301 to porous P-spodumene 305 in a gas of CO2/H2O injected as stream 306 to catalyse the conversion reaction, where the reaction temperature of about 900°C is maintained by heating the reactor using renewable power 307 and the CO2/H2O gas is ejected as stream 308 . In Stage 2, a carboniser reactor is used to cabonise the P-spodumene 305 from Stage 1 where the CO2 is extracted from a stream 309 of CCWsteam and recycled CCWsteam stream 308 to produce carbonated P- spodumene 310 and the CO2 depleted CO2 steam 306, which is used in Stage 1. The reaction temperature of about 500°C is controlled by an external heat exchanger (not shown). In the Stage 3, a bicarboniser reactor, an aqueous slurry of the carbonated P- spodumene powder 310 is formed with water 311 and the CO2 stream 312 is sparged into the slurry to dissolve lithium bicarbonate from the carbonated P-spodumene. The temperature of the bicarboniser reactor is maintained near an ambient temperature by a heat exchanger (not shown) to maximise the solubility of the lithium bicarbonate. The aluminosilicate solids are filtered from the slurry and the water is preferably extracted using a dryer (not shown) to produce a dry aluminosilica powder 304 and an solution of lithium bicarbonate 313, and unreacted CO2/H2O 312 is used in the Stage 2 reactor. Steam (not shown) generated from excess heat in the flow circuit may be added to this gas stream to generate the required CChi hO ratio for the Stage 2 reactor. In Stage 4, a precipitator, the lithium bicarbonate solution is heated to about 90°C to precipitate Lithium Carbonate and generate at CO2 stream 314, with water vapour which is mixed with the input CO2 stream 302 to form the stream 312. The slurry formed by precipitation is filtered so the product lithium carbonate is separated and dried (not shown) to produce the powder product 303. The water 315 is cooled (not shown) and is reinjected into the Stage 3 bicarboniser reactor. The process circuit shows that the inputs to the process are a-spodumene and CO2 and there is no net water use. [0061] In consideration of the third aspect of the present invention, the process flow of Figure 4 shows how streams of a- spodumene 401 and limestone 402 can be used to makes a product of lithium carbonate 403, aluminosilicate 404, and lime 405 in a five stage process. In Stage 1, a calciner reactor is used to convert the a-spodumene 401 to porous P-spodumene 406 in a gas of CO2/H2O injected as stream 407 from the Carboniser reactor to catalyse the conversion reaction, where the reaction temperature of about 900°C is maintained by heating the reactor using renewable power 408 and the CO2/H2O gas is ejected as stream 409. In stage 2, a second calciner reactor is used to convert the limestone 402 into lime 405 and a CO2 stream 409 using renewable power 410 to provide the heat for the process, when account is taken of recuperation of heat from the lime and CO2 streams to preheat the limestone (not shown). The amount of limestone to spodumene is in proportion to the amount of CO2 required to transform the lithium in the a-spodumene 401 to lithium carbonate 403. The net residual heat from the Stage 1 and Stage 2 processes are used for the processes in Stages 3-5 using, where appropriate, heat exchangers. In Stage 3, a carboniser reactor is used to carbonise the P-spodumene 406 from Stage 1 where the CO2 is extracted from a stream 411 of CCh/steam to produce carbonated P-spodumene 412 and the CO2 depleted CO2 steam 407, which is used in Stage 1. The reaction temperature of about 500°C is controlled by an external heat exchanger (not shown). In the Stage 4, a bicarboniser reactor, an aqueous slurry of the carbonated P-spodumene powder 412 is formed with water 413, and the CO2 stream 414 is sparged into the slurry to dissolve lithium bicarbonate from the carbonated P- spodumene. The temperature of the bicarboniser reactor is maintained near an ambient temperature by a heat exchanger (not shown) to maximise the solubility of the lithium bicarbonate. The aluminosilicate solids are filtered from the slurry and the water is preferably extracted using a dryer (not shown) to produce a dry aluminosilica powder 404; the solution of lithium bicarbonate 415; and unreacted CO2/H2O 416 which is used in the Stage 2 reactor. Steam (not shown) generated from excess heat in the flow circuit may be added to this gas stream to generate the required CO2:H2O ratio for the Stage 3 reactor. In Stage 5, a precipitator, the lithium bicarbonate solution 415 is heated to about 90°C to precipitate lithium carbonate and generate at CO2 stream 416, with water vapour which is mixed with the input CO2 stream 409 to form the stream 414. The slurry formed by precipitation is filtered so the product lithium carbonate is separated and dried (not shown) to produce the powder product 403. The water 417 is cooled (not shown) and is reinjected into the Stage 4 bicarboniser. The process circuit shows that the inputs to the process are a-spodumene and limestone and there is no net water use.

[0062] The advantage of the embodiment described in Figure 4 is that the process can be carried out in remote locations where renewable power is plentiful, and carbonate minerals such a limestone, dolomite or magnesite are available to produce the CO2 on demand. In comparison to current processes, there is no need to combust fuels for processing stages, or to use difficult roasting processes in sulphuric acids, or to use soda ash to precipitate lithium carbonate, or to use large amounts of water in such processes including acid generation. The integration of the processes of this disclosure have not been linked to the processes of grinding and beneficiating the mined spodumene to remove gangue by processes such as floatation. The demand for water is limited to a make-up of evaporation losses. A further advantage is that the aqueous processes of bicarbonation and precipitation are those that may be used in making high purity lithium carbonate by repeating this process to remove impurities.

[0063] As shown in Figure 1, there may be a device for producing carbonated 0- spodumene. The device may comprise a carboniser reactor 101 having a powder inlet 105 and a powder outlet 110. It may be appreciated that the powder inlet 105 has a rotary valve 105 for allowing the feed 102 to go into the carboniser reactor 101 only. The powder inlet may be adapted to receive 0-spodumene powder 102, and wherein the powder outlet may allow for carbonated 0-spodumene to exit the carboniser reactor, which may be connected to the powder outlet of the carboniser reactor 101.

[0064] The carboniser reactor 101 may be in fluid communication with a first gas inlet 103 and a first gas outlet 107, wherein the first gas inlet 103 may distal to the powder inlet, and wherein the first gas outlet is distal to the powder outlet; wherein the gas comprises carbon dioxide and water. An external heat transfer segment 106 in thermal communication with the carboniser reactor 101 wherein the segment 106 is adapted to maintain a temperature in the carboniser reactor in the range between 400°C to 600°C.

[0065] As shown in Figure 2, the device may further comprise a phase change reactor 201 having a second powder inlet 207 and a second powder outlet 205, wherein the second powder outlet 205 is in fluid communication with the powder inlet 207 of the carboniser reactor 202, wherein the second powder inlet 207 is adapted to receive a- spodumene powder 203. The phase change reactor 201 may be in fluid communication with a second gas inlet 204 and a second gas outlet 206, wherein the first gas outlet 107 is in fluid communication with the second gas inlet 209. A second external heat transfer segment 208 may be in thermal communication with the phase change reactor 201 , wherein the second external heat transfer segment 208 may be adapted to maintain a temperature in the phase change reactor in the range between 800°C to 1000°C.

[0066] As shown in Figure 1, the device may further comprise a first filter 108 for filtering the powder from the gas prior to entering the first gas outlet 107 and as shown in Figure 2, the device may further a second filter 211 for filtering the powder from the gas prior to entering the second gas outlet. While not shown in Figure 2, it may be appreciated that the first filter 108 may also be present so that powders do not clog the gas outlet/gas inlet lines 209.

[0067] As shown in Figure 3, the device may be adapted to produce lithium carbonate powder from carbonated [3-spodumene generated from the device as shown in Figures 1 and 2. The device for producing lithium carbonate powder from carbonated [3-spodumene may further comprise: a bicarboniser reactor 3 and a precipitator segment 4 each having an inlet 310 and an outlet 313, wherein the bicarboniser reactor 3 is positioned between the carboniser reactor 2 and the precipitator segment 4, wherein the inlet of the bicarboniser reactor 3 is in connection with the powder outlet of the carboniser reactor 2, and wherein the outlet of the bicarboniser reactor is in connection with the inlet of the precipitator segment 4. The bicarboniser reactor 3 may comprise a third gas inlet 312, a water inlet 311, and a third gas outlet 309, wherein the bicarboniser reactor 3 is in fluid communication with the third gas inlet 309, the water inlet 311 and the third gas outlet 309, wherein the third gas inlet 309 is for injecting carbon dioxide 302 into an aqueous slurry of carbonated 0-spodumene, wherein excess carbon dioxide and steam enters the third gas outlet 309. While not shown in Figure 3, the bicarboniser reactor 3may comprise a heat exchanger for maintaining the reactor 3 at near an ambient temperature.

[0068] As shown in Figure 3, a solid filter for filtering aluminosilicate solids from the aqueous slurry is positioned between the outlet of the bicarbonate reactor and the inlet of the precipitator segment 4, wherein the inlet of the precipitator segment is adapted to receive lithium bicarbonate solution 313 from the filtration of the aqueous slurry when exiting the bicarboniser reactor 3. The precipitator segment comprises a heat transfer segment for heating the lithium bicarbonate solution to a temperature between the range of 85 to 95°C.

[0069] The precipitator segment may have a fourth gas outlet 314, wherein the carbon dioxide emitted from the heated solution is reinjected to the third gas inlet 312 of the bicarboniser reactor 3. The precipitator segment 4 may further comprise a second solid filter or a removable filter for collecting wet lithium carbonate. It may be appreciated that excess water from the filtration may be recycled into the bicarboniser reactor 3 via the water inlet 311. The device may further comprise a drying station (not shown) for drying the wet lithium carbonate from the second filter to produce lithium carbonate powder 303.

[0070] As shown in Figure 4, while the device and/or system is similar as described, it may be appreciated that a carbon dioxide generator is in fluid communication with the third gas inlet of the bicarbonator reactor. An example means of producing CO2 may be by calcining limestone powder 402 to give CO2 gas 409 which is injected to the gas inlet 414 of the bicarboniser reactor. For minimising the use of nonrenewable energy, renewable energy/power 410 may be used to power the calciner or heat required to calcine the limestone powder in this reactor. The lime powder 405 produced by this example process may be used for other purposes to maximise uses for useful products. The device may further comprise an extraction station, wherein the extraction station is adapted for extracting lithium from dried lithium carbonate using a weak acidic solution selected from the group of: acetic acid, and oxalic acid.

[0071] Further forms of the invention will be apparent from the description and drawings.

[0072] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms, in keeping with the broad principles and the spirit of the invention described herein.

[0073] The present invention and the described preferred embodiments specifically include at least one feature that is industrial applicable.