Production of lithium chemicals and metallic lithium

Abstract

To provide a process and a system for producing lithium oxide from lithium nitrate.SOLUTION: Lithium nitrate is thermally decomposed in a manner such that a fraction of the lithium nitrate forms lithium oxide, and such that a remaining fraction of the lithium nitrate does not decompose to lithium oxide. The thermal decomposition may be terminated after a determined time period to ensure that there is a remaining fraction of lithium nitrate and to thereby produce a lithium oxide in lithium nitrate product. The lithium oxide in lithium nitrate product may have one or more transition-metal oxides, hydroxides, carbonates or nitrates added thereto to form a battery electrode. The lithium oxide in lithium nitrate product may alternatively be subjected to carbothermal reduction to produce lithium metal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] Processes, systems and methods for producing a range of lithium chemicals and lithium metal The products of such processes, systems and apparatus are, inter alia, lithium This could be advantageous for battery manufacturing. Also, the lithium metal produced can be used for alloying purposes. (e.g., lithium-aluminum alloys for use in the aerospace industry and other applications) ) can also be used. [Background technology]

[0002] Renewable energy produced by electric vehicles (EVs) and rooftop solar photovoltaic (PV) panels, etc. The market price of lithium batteries suitable for large-scale energy storage applications, such as the storage of renewable energy, rose by 1.2% in 2012. From 2015 to 2018, the ceiling price for effective storage capacity will increase from approximately US$1,000 / kWh. During that time, the power per kilogram of lithium battery has fallen by 80%. The capacity to store electricity (unit: kWh / kg) and the ratio of the capacity of the battery to transmit and receive electricity (charging and The electricity consumption and discharge (kWh / kg) continues to rise, albeit slowly.

[0003] Adoption of energy storage systems in conjunction with the electrification of road transport and the output of renewable energy systems In response to the prediction of the adoption of storage systems to enable distribution of electricity according to demand, From mining for lithium resources to producing complete battery packs (thousands of individual lithium cells) Many value-added tasks are performed until the final assembly of the Investment in lithium-ion batteries is booming worldwide. The lifespan, charge / discharge speed and efficiency, storage capacity and safety of lithium batteries Continuing to improve is supported by a certain degree of acceptance.

[0004] To recover lithium values ​​in a form suitable for use in the manufacture of lithium batteries, The combination of these challenges has led to the widespread adoption of lithium batteries and their impact on the environment. This may be the cause of delays in realizing the expected benign applications. Many value-adding activities, including mineral exploration and assembly of complete battery packs, are also taking place. Although improvements have been made to reduce their cost and / or environmental impact, Processing operations that convert lithium-containing minerals into lithium chemicals suitable for the manufacture of lithium batteries. There was little attention paid to the improvements.

[0005] The most important component of a lithium battery, and the one most suited to cost reduction, is There are two terminals in a lithium battery: a positive terminal (cathode) and a negative terminal (anode). In particular, the cathode. Current lithium battery cathodes consist of lithium, various transition metals, and Early high performance lithium batteries contained a single transition metal, i.e., cobalt. Lithium-cobalt-only chemistry (so-called LCO batteries, i.e. lithium cobalt oxide) there were.

[0006] Recently, LMN (i.e., lithium manganese nickel oxide), NMC (nickel manganese Lithium batteries such as lithium cobalt oxide (i.e., LiMO2 and Li2M'O3 (formula where M is a transition metal with an oxidation state of +3 and M' is a transition metal with an oxidation state of +4) Cobalt is relatively rare and expensive, so batteries with cathodes made from cobalt have been developed. Because LCO batteries are prone to ignition, battery manufacturers are replacing some or all of the cobalt with iron, They are trying to replace them with more abundant transition metals such as nickel, manganese and titanium.

[0007] For example, US2019 / 0212267 describes the process for producing micron / nanometer-sized nanoparticles from precursor materials. Lithium-based compounds with sizes on the order of 100 nm (e.g., LiFePO4, LiMnPO 4, LiFeMnPO4, LiMnNiO2, Li4Ti5O 12 ) and other small particles The resulting small particles are used as electrode materials in electrochemical cells, including batteries. It is used as a fee.

[0008] To prepare these compounds, the oxide of a transition metal and (in the first example) lithium carbonate and The mixture is heated at high temperature (800-900°C) and mixed with lithium hydroxide (as monohydrate) in the desired ratio. The mixture is heated at 300°C for many hours, the resulting solid is ground into a very fine powder, and then The powder is coated (printed) onto a thin copper foil to form the cathode.

[0009] The main sources of lithium for such compounds are spodumene and The present inventors have discovered that the lithium-rich metal silicate minerals are the source of the lithium. Patents for improved processes for recovering lithium carbonate and lithium hydroxide (e.g. US10,131,968, CN106906359 (both This process is based on technology that is more than half a century old. The relevant content of WO2017 / 106925 is hereby incorporated by reference. To be incorporated.

[0010] The process of WO2017 / 106925 is directed to the major chemicals used in the process. , i.e., "closed" as far as nitric acid is concerned. WO2017 / 106 In the 925 process, the nitric acid used in the process is recovered and reconstituted for reuse. In addition, WO2017 / 106925 describes a method for producing a lithium nitrate by thermally decomposing the lithium nitrate. This gives lithium oxide and nitrogen oxides, which can then be recycled back into the process by reforming nitric acid. However, lithium oxide may be used in the manufacture of batteries. Being a difficult material to process, the process of WO2017 / 106925 uses lithium oxide. The formula is lithium carbonate, lithium hydroxide and lithium metal (i.e., lithium carbonate and Each of the lithium ions is an industry-specification chemical for the manufacture of lithium batteries. Furthermore, the process of WO2017 / 106925 is only formed as an intermediate. In the process, the amount of lithium oxide formed is adjusted so that as much lithium carbonate as possible is formed. The amount of lithium carbonate and lithium hydroxide formed is maximized. The lithium ore may be conveniently refined using any of the other known processes for refining lithium ore. Not manufactured.

[0011] References herein to background and prior art are made to such techniques as would be within the ordinary and / or skill of a person of ordinary skill in the art. No admission is made that the information contained herein is accurate or that it forms part of the general public knowledge. The present disclosure is not intended to limit the processes and systems described herein in any way. There is none. Summary of the Invention

[0012] Disclosed herein is a process for producing lithium oxide from lithium nitrate. Lithium silicates are a major class of naturally occurring lithium-rich minerals, namely, metallosilicates. They may in turn be prepared from salts (including mica and clay) and brine. For example, lithium nitrate The invention relates to WO2017 / 106925 (i.e., US10,131,968 and CN1069 It may also be prepared by a process such as that described in US Pat. No. 6,359.

[0013] The process comprises the steps of: adding lithium nitrate to a solution of lithium oxide; The method includes thermally decomposing the lithium oxide so that the remaining fraction of the lithium oxide does not decompose to lithium oxide. In other words, the process disclosed herein converts only a portion of the lithium nitrate into lithium oxide. Therefore, the products of this process are lithium nitrate and lithium oxide. The process is terminated after a set time, resulting in the formation of a lithium nitrate blend. A fraction is ensured to remain, thereby producing a lithium oxide-containing lithium nitrate product. Cut.

[0014] The process is a process in which the products are lithium hydroxide, lithium carbonate and lithium metal, WO2 This process is in contrast to the process disclosed in US Pat. The applicant intends to produce a fraction of lithium oxide in the product. Lithium oxide has a high percentage of lithium (e.g., lithium hydroxide and lithium carbonate). However, as mentioned above, lithium oxide is It is a difficult product to use as a raw material for the production of lithium battery cathodes. The problem is that lithium oxide is very difficult to dissolve. As a result, for example, the cathode of a lithium battery To be used as a starting material in the production of materials (compounds of lithium and transition metal oxides) In order to achieve this, severe conditions (i.e. high temperature and long heating time) are required. To be able to produce thium as a feedstock, complex processing facilities are required ( (Existing lithium refining facilities cannot handle this.) For this reason, lithium oxide, especially lithium It is not used as a raw material for manufacturing battery cathodes. Existing lithium refineries are not intended for the production of lithium oxide.

[0015] This process also contrasts with the method disclosed in US2009 / 0212267. US2009 / 0212267 describes the thermal decomposition of lithium nitrate to form lithium oxide. Of course, it is also possible to thermally decompose an appropriate fraction of lithium nitrate to form lithium oxide ( i.e., to prevent the remaining fraction of lithium nitrate from decomposing into lithium oxide). Moreover, US2009 / 0212267 does not disclose or relate to From the extensive list of lithium salts listed as precursor materials, lithium nitrate was selected. In this regard, US2009 / 0212267 does not distinguish between lithium nitrate and It melts at a relatively low temperature of 260°C, i.e. the solids formed from the decomposed fractions The unique properties of lithium nitrate, such as its ability to host lithium oxide Rather, the focus of US2009 / 0212267 is on the specific grinding media. The method involves using a gas to grind the precursor into extremely fine particles for subsequent formation into battery electrodes. do.

[0016] On the other hand, the inventors have surprisingly found that a blend of lithium oxide and lithium nitrate: It was realized that this could be a suitable raw material for battery production and for the production of lithium metal. For example, at temperatures above the melting point of lithium nitrate (i.e., above about 260°C), lithium oxide A slurry or paste of molten lithium nitrate containing lithium can be produced. If the temperature is maintained above the melting point of tungsten (e.g., in the processing environment), The slurry can then be conveniently transported using pumps and pipelines. When cooled below its melting point (e.g., in handling, transport and storage settings), lithium oxide The lithium nitrate product containing ammonium is preferably formed into prills, pellets, flakes, etc. may be (or the product may suitably be in such a form).

[0017] For example, after forming them into prills and shipping them, the battery manufacturer The lithium product is simply heated until the lithium nitrate phase softens (i.e., above about 260°C). This allows, for example, a bath of molten LiNO3 salt containing dispersed solid lithium oxide crystals to be and adding a transition metal oxide, hydroxide, carbonate or nitrate (e.g., powder and (as a catalyst) can be added along with other necessary electrode materials. The resulting mixture can then be further heat treated by the manufacturer. Surprisingly, the moderate conditions (i.e., the many hours and high temperatures typically required (8 It requires less time and lower temperatures than the conventional method (00-900°C), and contains lithium oxide. It was realized that the lithium nitrate product could be used to form a cathode material for batteries. In this way, the inventors have realized that lithium oxide can be easily used as a starting material for, for example, battery production. As mentioned above, lithium oxide contains a relatively high percentage of lithium. This has the advantage that

[0018] In one embodiment, the fraction of lithium nitrate that is thermally decomposed to lithium oxide is The lithium nitrate may be about 50 to 90% of the lithium nitrate. More specifically, the lithium nitrate to be thermally decomposed may be The fraction may be about 70-90%. At this conversion rate, the resulting hot slurry (i.e. At temperatures above the melting point of lithium nitrate, it flows easily.

[0019] The figure of 90% thermal decomposition of lithium nitrate indicates a high conversion rate to the oxide. and recycles up to 90% of the nitric acid produced as part of the process (which is lost). In fact, the ratio of Li2O to LiNO3 is In this case, it may be adjusted to suit the needs of the end user (e.g., battery manufacturer). For example, when 82% of LiNO3 is decomposed to Li2O, the mixture becomes LiNO3 and Li2O. The weight ratio can be 50:50.

[0020] For example, if 90% of lithium nitrate is thermally decomposed to lithium oxide, 66 A paste containing 34% by weight of Li2O (solid crystal) and 34% by weight of LiNO3 (liquid) was prepared. The lithium content of the battery is 34.5% by weight. %, i.e., lithium carbonate and lithium hydroxide monohydrate were 19% by weight and 16.7%, respectively. % Li by weight. Therefore, the process disclosed herein provides A high percentage of Li can be supplied to battery manufacturers, for example.

[0021] In one embodiment, prior to pyrolysis, lithium nitrate is dissolved in water to form a molten lithium nitrate salt. It may be heated in a separate preheating step, and the molten lithium nitrate may then be sent to a pyrolysis step. The pyrolysis step may be a separate step from the preheating step. Lithium nitrate (e.g., crystalline) is preheated The preheating step may be performed by converting lithium nitrate (e.g., sintered lithium) into lithium oxide. The crystal is heated to about 400° C. (e.g., in a hot process stream) The vessel may include a melting (e.g., a heat exchanger) vessel that can This heating converts the lithium nitrate into a transparent, highly fluid (i.e., mobile) molten salt. In the form of a molten salt, lithium nitrate is electrically conductive, which in turn transforms into This means that in a separate pyrolysis step, molten lithium nitrate can be used and reacting at a temperature higher than the decomposition temperature of lithium nitrate (i.e., above 600°C) (more aggressively The molten lithium nitrate can be further decomposed by applying heat (typically thermal decomposition). Typically, the thermal decomposition step involves: A separate preheating step requires electrical induction heating, which tends to be expensive, but the process stack is heated at high temperatures. A ream can be used, and as a result the lithium nitrate can be preheated (e.g., to 400°C). Therefore, using two stages in series can improve the process economics. The electrical energy required to heat lithium nitrate above its decomposition temperature (i.e., above about 600°C) This can reduce energy.

[0022] In one embodiment, the thermal decomposition of lithium nitrate involves direct or indirect heating of the lithium nitrate. Heating may include heating at pressures equal to or greater than ambient / atmospheric pressure (e.g., 9 barg). The pressure may be increased up to 100 bar (including up to 100 bar).

[0023] In one form, direct heating is achieved by induction heating (e.g., an electric heater disposed within the pyrolysis reactor). The lithium nitrate is decomposed to a desired extent by an induction coil. That's fine too.

[0024] In another form, lithium nitrate can be decomposed in an indirectly (externally) heated vessel. That is, the lithium nitrate is decomposed in a desired manner and to a desired extent.

[0025] During such direct or indirect (e.g., induction or external) heating processes, the container Care may be taken to avoid contact between the contents of the container and any gases, including atmospheric air. When fuel is burned to provide the external heat required to decompose the lithium oxide, Care may be taken to avoid contact between the contents of the container and the products of combustion of the fuel.

[0026] As mentioned above, lithium nitrate thermally decomposes at temperatures above about 600° C. In one embodiment, The completion of the thermal decomposition of lithium nitrate is achieved by removing the partially decomposed products at their decomposition temperature of approximately 6 This can be achieved by simply cooling the mixture to below 00°C. The lithium oxide-containing lithium nitrate product is then When the temperature is maintained at about 260°C to about 600°C, the product contains solid lithium oxide. The lithium nitrate may be in the form of a paste or slurry containing molten lithium nitrate. / Transport the slurry through the process (e.g., by suitable pumps, piping, conveyors, etc.) The paste / slurry may then be further cooled to a temperature below about 260° C. to solidify. For example, the lithium oxide-containing lithium nitrate product may be prepared as described above. The solid product obtained may be manufactured into the form of prills, pellets, flakes, and the like.

[0027] For example, if the resulting solid product is to be prilled, this may be done in a prill tower. The prill column is free of water vapor and carbon dioxide (i.e. The resulting prills may be packed in a sealed container. It can be packed in small packages or handled in bulk, and is less difficult to handle than, for example, flake caustic soda. As a result, the solid lithium oxide-containing lithium nitrate product is easily transported, etc. It can be done.

[0028] For example, if the resulting solid product is flaked, such as caustic soda, the solid acid The molten lithium nitrate (i.e., hot slurry / paste) containing lithium chloride was cooled. The resulting cooled solid product may then be coated onto the exterior surface of the drum. The product may be lifted off the surface of the drum with a blade or the like to form a flake-like product.

[0029] Battery manufacturers use prills, flakes, pellets, etc. until the lithium nitrate phase softens. Heating, followed by the oxides, hydroxides, carbonates or nitrates of transition metals (as powders), Simply add any other necessary ingredients and then heat the resulting mixture as needed to supply the electrodes. As a result, the solid lithium oxide-containing lithium nitrate product can be produced. This makes it an ideal feed material for the manufacture of battery electrodes.

[0030] In one embodiment, oxygen and nitrogen oxides may be produced by pyrolysis (i.e., by-products). These gases can be recovered and used, for example, in a nitric acid production step (i.e. In the nitric acid production stage, nitrogen oxides and oxygen are absorbed in an aqueous solution. nitric acid may be formed in a known manner. As a result, nitric acid from the process may be "regenerated." Furthermore, the recovery and use of such by-product gases is a As far as this goes, the process can be "closed."

[0031] In one embodiment, a replenishing stage may be provided to make up for losses such as nitric oxide. In the replenishment phase, nitrogen oxides are produced by catalytic combustion of ammonia in excess air. It can be produced by catalytic combustion (i.e., widely used on an industrial scale by the Ostwald process). The resulting gaseous stream may be recovered and sent to a nitric acid production stage to produce further nitric acid. This can further contribute to the process being "closed" as far as nitric acid is concerned.

[0032] In one embodiment, the nitric acid produced in the nitric acid production step is treated with a thermal decomposition step For example, prior to pyrolysis, nitric acid may be used to oxidize the lithium-containing silicate mineral ( For example, active materials such as spodumene or other lithium-rich metal silicate minerals The mixture may then be mixed with the silicate mineral (a lithium ore that has been activated). A leaching step is also performed in which lithium values ​​are leached from silicate minerals as lithium nitrate. This lithium nitrate may be separated and then subjected to the thermal decomposition step described above to produce lithium oxide. As a result, a lithium nitrate product containing ammonium may be formed. Like the 925 process, this process is again considered "closed" as far as nitric acid is concerned. It is possible.

[0033] In one embodiment, the process comprises concentrating the lithium nitrate solution produced in the leaching step. It may further include a crystallization step to crystallize and form relatively pure crystalline LiNO3. The crystallized LiNO3 may be separated from the solution by centrifugation or the like. The resulting crystalline LiNO3 is subjected to a thermal decomposition process to produce lithium oxide-containing lithium nitrate. may be formed.

[0034] In a process variant, some or all of the lithium oxide-containing lithium nitrate products of the thermal decomposition are The lithium oxide of the pyrolysis may be converted to lithium metal by a reduction process or the like. The lithium nitrate product containing fluorine may be sent to the reduction process at a high temperature (i.e., without intermediate cooling). The lithium metal product of the reduction process is used in high tech / advanced alloys (e.g. aerospace The product is economically advantageous in that it can be applied to applications other than battery manufacturing, such as It can be represented.

[0035] In one embodiment of this process variation, the reduction process is carried out using a lithium oxide-containing lithium nitrate. The lithium nitrate product is mixed with a carbon source (e.g., ashless carbon briquette) and cooled to 100°C. This may include heating the mixture to a temperature sufficient to initiate a reaction between the rubber and the carbon. It has been pointed out that the reaction between lithium nitrate and carbon is highly exothermic and essentially The reaction is based on the same principle as gunpowder (i.e., potassium nitrate is used instead of lithium nitrate). Typically, the temperature of this reaction is determined by the amount of lithium nitrate and lithium oxide present. The lithium contained in the mixture is sufficient to be reduced to lithium metal, while the carbon source is converted to an acid in a gaseous form. It will be turned into.

[0036] The reaction between lithium nitrate and carbon can be initiated while the reduction process continues. Part of the heat is generated by the continued reaction of the lithium nitrate component of the blend product with the carbon source. As a result, the reduction step In this case, the reaction between lithium nitrate and carbon and the reduction reaction of lithium oxide can be carried out in parallel. As mentioned above, the former is highly exothermic, while the latter is highly endothermic.

[0037] In this regard, the amount of thermal energy required to drive the reaction for the production of lithium metal A portion of the nitrate in the pyrolysis product can be provided by the reaction of lithium nitrate with a carbon source. The ratio of lithium oxide and lithium oxide may be controlled.

[0038] In one embodiment of this process variation, immediately after reduction to lithium, lithium as a vapor is added. Rapid cooling of lithium metal and gaseous carbon oxide reduces the tendency for the reaction to reverse (i.e., lithium metal is oxidized to lithium oxide, and gaseous carbon oxide is reformed into elemental carbon) For example, the reversal of the reaction forming lithium metal vapor and gaseous carbon oxide can be prevented. To prevent this, the steam blend may be passed through a convergent-divergent (Laval) nozzle, or other suitable means may be used to reduce the amount of superheat. The supersonic expansion allows rapid cooling. This is achieved by maintaining an appropriate pressure differential between the

[0039] In one embodiment of this process variation, the temperature of the gas exiting the Laval nozzle is By lowering the temperature below the boiling point of lithium metal, the lithium metal is dispersed in carbon dioxide gas as fine particles. This allows the liquid lithium metal to be condensed into liquid droplets, which then exchanges with gaseous carbon dioxide. For example, liquid lithium metal and gaseous carbon dioxide can be separated in a cyclone separation stage. The cyclone separation stage produces a liquid lithium metal product, which can then be passed through The solid lithium metal product is then cooled and stored safely in an airtight container. or by protecting it from contact with air or moisture (for example, by storing it under non-aqueous liquids such as oil). The separated gaseous carbon dioxide may be collected and used as fuel. For example, the lithium-rich silicate mineral spodumene can be recycled. It can be used to calcinate concentrates of uranium (the original feedstock to the process) (e.g., If the gaseous carbon oxide produced is carbon monoxide, it is burned in air to release energy. and produce carbon dioxide).

[0040] In another embodiment, the source of lithium nitrate for the pyrolysis process is a salt of Salt lakes in South America, such as those in the "Lithium Triangle" of Argentina, Bolivia and Chile This may include saltwater from the ocean, etc.

[0041] In this alternative embodiment, the lithium nitrate from the salt flats is enriched with lithium from the salt flats processing stage. A saltwater containing lithium chloride (LiCl) is collected and mixed with nitrate such as Chilean saltpeter (NaNO3). The resulting mixture may then be mixed with a salt of lithium nitrate. To produce the solution, it may be subjected to a heat treatment step, such as evaporation.

[0042] In this alternative embodiment, the heat treatment of the mixture of lithium-rich brine and nitrates is carried out in a conventional manner. Such as precipitating salt (NaCl) from solution, thereby producing lithium nitrate solution. This solution may then be used to produce the lithium nitrate feedstock for the pyrolysis step. It serves as the foundation.

[0043] Also described herein is a reduction process for producing lithium metal from lithium nitrate. The reduction process involves mixing lithium nitrate with a carbon source (e.g., ashless carbon dioxide). The lithium nitrate is heated to a temperature sufficient to initiate a reaction with the carbon and lithium nitrate. thereby reducing the lithium to lithium metal and oxidizing the carbon source to a gaseous state. .

[0044] Advantageously, as mentioned above, high temperatures are provided to reduce the lithium to lithium metal. Part of the heat energy required to maintain the temperature is provided by the highly exothermic reaction of lithium nitrate with carbon. For example, the highly exothermic reaction of lithium nitrate with carbon may result in at least one This could result in a rise in temperature to 500°C (possibly 2000°C). At temperatures of 1000 K, the lithium in the feed is reduced to lithium metal.

[0045] In one embodiment, the lithium nitrate that is heated is a mixture of lithium nitrate and lithium oxide. This mixture may be the product of a pyrolysis process as described above. This mixture can be fed into the lithium reduction process as a hot paste / slurry. Again, the high temperatures required to reduce the lithium oxide to lithium metal must be maintained. The rate of heat energy required to produce the desired result is due to the strong thermal interaction between the lithium nitrate component of the blend and the carbon. It may be brought about by a thermal reaction.

[0046] In one embodiment, the reduction is immediately followed by addition of lithium metal as vapor and gaseous carbon oxide (nitrate). (including nitrogen gas produced by the reaction of lithium with carbon) into liquid lithium metal and by-product gases For example, the reaction may be rapidly cooled to form lithium metal vapor and gaseous carbon oxide. The gas is then rapidly cooled by expansion, such as supersonic expansion through a convergent-divergent (Laval) nozzle. Good too.

[0047] The resulting liquid lithium metal and gaseous carbon oxides are separated by a cyclone separation step (e.g., The gases may be separated from each other by, for example, passing them through two cyclone separators connected in series. Optionally, carbon monoxide (e.g., carbon monoxide) may be recovered and reused as a fuel.

[0048] Also disclosed herein is a system for producing lithium oxide from lithium nitrate. The system thermally decomposes a fraction of lithium nitrate in it to form lithium oxide. and the remaining fraction of lithium nitrate does not decompose to lithium oxide. The pyrolysis reactor includes a

[0049] In one embodiment, the pyrolysis reactor may comprise a tank reactor (optionally a pressure vessel). The tank reactor is designed so that molten lithium nitrate can be added to the top of the tank reactor. The tank reactor may further include a slurry of lithium nitrate containing lithium oxide. The tank reactor may be arranged so that the liquid can be withdrawn from the bottom of the tank reactor. The reactor provides a gas space above the slurry, which is used for the decomposition of lithium nitrate. The nitrogen oxides and oxygen produced by the exhaust gas may be collected and removed.

[0050] Typically, the tank reactor is operated at temperatures above about 600° C. (i.e., the decomposition temperature of lithium nitrate). This heating can be either direct or indirect. Good too.

[0051] For example, induction heating coils can be placed inside tank reactors to directly heat their contents. In this regard, molten lithium nitrate is conductive and can be heated using electrical induction. May be heated.

[0052] In another example, a fuel burner is used to heat the reactor externally. The reactor may be heated externally, for example by burning a fuel.

[0053] The contents of the tank reactor are stirred by natural circulation, such as by the action of electric induction heating coils. In the case of an externally heated reactor, the contents may be stirred with a suitable impeller. .

[0054] In a variant, the tank reactor may be in the form of a pressure vessel in order to operate at pressures above ambient. For example, the reactor may be operated at pressures up to about 9 bar gauge (10 bar absolute). At these temperatures and pressures, typical production rates for a tank reactor are The article can include a lithium nitrate liquid containing solid crystals of lithium oxide.

[0055] In one embodiment, the system may further include a pre-heating (e.g., heat exchanger) vessel. The heated vessel may optionally be agitated. In the preheated vessel, lithium nitrate (e.g., in its anhydrous form) is added. The relatively pure crystalline form may be heated to a temperature above its melting point temperature of about 260°C. Optimally, lithium nitrate may be heated to about 400°C. At this temperature, lithium nitrate The lithium becomes highly mobile and conductive and migrates directly to the pyrolysis reactor, forming a lithium oxide-containing nitrate. As described above, the preheating step can be carried out in a manner suitable for forming the lithium oxide product. The use of vessels can improve the economics of the process because pyrolysis reactors typically , electric induction heating or external burners burning fuel, each of which are expensive. While other preheat vessels tend to use hot process streams to heat lithium nitrate. This is because the aluminum can be preheated and melted.

[0056] If the tank reactor is in the form of a pressure vessel, the molten lithium nitrate from the preheat vessel is Before being sent to the decomposition reactor, the pressure may be increased by a suitable pump (e.g., about 9 up to the bar gauge).

[0057] In one embodiment, the system includes a nitric acid production reactor (e.g., a known absorption tower, The pyrolysis reactor may further include a heat exchanger-absorber or compact heat exchanger-absorber. The nitrogen oxides and oxygen that are extracted are sent to a nitric acid production reactor where they are absorbed in an aqueous solution and react with the known Nitric acid may be formed in the process. If the pyrolysis reactor is in the form of a pressure vessel, the recovered gas may be The system may be arranged so that the gas can flow under pressure to the nitric acid production reactor.

[0058] In one embodiment, the system comprises a leaching reactor (e.g., a pressure leaching vessel such as an autoclave). In the leaching reactor, the nitric acid produced in the nitric acid production reactor is leached with lithium Mixed with containing silicate minerals (e.g., activated beta forms of silicate minerals such as spodumene) In the leaching reactor, the lithium values ​​in the silicate minerals are extracted from the silicate minerals by leaching. Lithium nitrate may be separated (e.g., in a filtration step) and leached as lithium nitrate. and then fed to a pyrolysis reactor to produce lithium oxide (i.e., lithium nitrate containing lithium oxide). tium product) is formed.

[0059] In one embodiment, the system may further include a crystallizer. The crystallizer may include a leaching stage. The lithium nitrate solution produced in the first step is concentrated and then crystallized to produce a comparative The system may be configured to form relatively pure anhydrous crystalline LiNO3. The separator may include a separator (e.g., a centrifuge) that separates the crystallized LiNO3 from the solution. and then reacting the separated crystals to form a lithium oxide-containing lithium nitrate product. The crystallized LiNO3 may be sent to a pyrolysis reactor (or preheat vessel).

[0060] In one embodiment, the system may further include a combustor. The combustor comprises a pressurized catalytic The combustor may be in the form of a combustor in which the ammonia may be burned in excess air. The gaseous product stream (oxides of nitrogen) from the combustor is collected and sent to a nitric acid production reactor. In this way, the combustor can be used to replenish nitric acid (to account for losses in the system). It can be provided for this purpose.

[0061] In one embodiment, the system comprises a pyrolysis reactor containing solid crystals of lithium oxide. A slurry containing lithium nitrate liquid was added to the carbon source (e.g., ash-free carbon briquettes). The method may further include a reduction furnace in which carbon may be mixed with the sulphur dioxide gas (SO2) to aid in reaction control. The lithium oxide-containing lithium nitrate slurry may be fed to the peripheral area of ​​the reduction furnace from the top to the center. The peripheral carbon may be fed to the center of the furnace, which is inclined toward the central reaction zone. In the reduction furnace, the slurry is mixed with lithium metal (i.e., gaseous lithium metal The blend may be heated (e.g., in the center of a furnace) to convert the fluorine-containing oxide to a metal oxide. Part of the heat may be obtained from the feed material itself (i.e., by the reaction of lithium nitrate with carbon). may be obtained).

[0062] In one embodiment, the slurry may be preheated in a holding vessel before being fed to the reduction furnace. Such preheating not only allows the use of hot process streams, but also the use of lithium nitrate slurry. The lithium oxide in the ree can also be made into a form suitable for feeding to a reduction furnace.

[0063] In one embodiment, the system determines the ratio of lithium nitrate and lithium oxide in the pyrolysis products. In this regard, the blend may further include a blending vessel in which the amount of the blended material can be controlled. Before being fed, additional lithium nitrate is added to the blending vessel to form a lithium oxide-containing lithium nitrate. Part of the thermal energy required for the reduction reaction to lithium metal The blend was optimized so that a portion of the cations could be obtained by reaction of lithium nitrate with a carbon source. This is also fine.

[0064] In one embodiment, the system may further comprise a flash cooling device. The cooling device may be in the form of a convergent-divergent (Laval) nozzle. The lithium metal product (i.e., gaseous) may be disposed at the upper outlet of the reduction furnace. The gas flows from the top of the furnace through a Laval nozzle, which causes (e.g., supersonic) The gaseous lithium metal is then cooled rapidly by the expansion of the liquid. Lithium metal can be formed.

[0065] In one embodiment, the system may further include a separation device. The separation device may include one or more The separation device may be in the form of a number of cyclones. The separation device separates the molten lithium metal into lithium metal. From the gases produced in the reduction furnace during conversion (e.g. carbon oxides, mainly CO, nitrogen oxides, etc.) The separated molten lithium metal can be stored in an optionally heated storage vessel (e.g., a The separated gases (e.g., carbon oxides) can be stored in a storage tank (e.g., a storage tank with a storage compartment) while the ... For example, the monoacid The oxidized carbon may be used in calcining the lithium-containing silicate mineral (i.e., leaching with nitric acid). (to produce an activated β-form so that

[0066] Also disclosed herein is a reduction furnace for producing lithium metal. The lithium nitrate-containing product is disposed to receive the lithium nitrate product together with a carbon source. The two mixtures are then heated to allow the lithium nitrate to react with the carbon, resulting in the formation of lithium The reduction furnace is designed so that carbon is supplied to the periphery of the reduction furnace. The lithium oxide-containing lithium nitrate product is supplied to the center of the reduction furnace. It is possible.

[0067] The reaction dynamics (including heat and pressure) and reaction structure are determined by the carbon (e.g., ashless carbon black). The rickets are fed to the periphery of the reduction furnace, and the lithium oxide-containing lithium nitrate product is fed to the center. In this regard, the carbon in the periphery is better controlled by feeding it into the lower region of the furnace. The reaction bed within the furnace may be configured to slope toward a central reaction zone disposed in a reduction zone. The reaction takes place within this reaction zone. In use, the carbon flows down the slope of the reaction bed of the reaction mass. As mentioned above, the reaction between lithium nitrate and carbon can be gradually fed to the central reaction zone. This will give a furnace temperature of at least 1,500°C (possibly 2,000°C). At such furnace temperatures, lithium oxide is readily reduced to lithium metal.

[0068] After the reaction starts, a proportion of the heat for the reduction furnace comes from the reaction of lithium nitrate with carbon. As mentioned above, the optimum ratio of lithium nitrate in the product to be fed to the furnace is Also, the lithium oxide-containing lithium nitrate product is supplied to a reduction furnace. The lithium nitrate may be preheated in a holding vessel prior to reduction (e.g., to melt the lithium nitrate). may otherwise be configured as described in the system above.

[0069] Also disclosed herein is a process for producing a battery electrode, the process comprising: Molten lithium nitrate (i.e., having lithium oxide dispersed therein - e.g. Lithium oxide-containing lithium nitrate is added to form lithium oxide (as dispersed solid lithium oxide crystals). The lithium oxide-containing lithium nitrate product is prepared by subjecting the lithium oxide-containing lithium nitrate product to a process as described above. It may be manufactured according to the process.

[0070] The process also includes the step of producing one or more transition metal oxides, hydroxides, carbonates, or nitrates. The resulting blend is then heated to 300° C., optionally with other necessary electrode materials. It can be processed to produce battery electrodes.

[0071] Embodiments of processes, apparatus and systems will now be described with reference to the accompanying drawings. The drawings are merely illustrative. The drawings are primarily intended to illustrate the concept of pure lithium nitrate (i.e., the lithium nitrate described herein). and / or a method as described in WO2017 / 106925 Conversion of lithium nitrate / lithium oxide blends produced by and the conversion of such blends to lithium metal. [Brief description of the drawings]

[0072] [Figure 1] FIG. 1 is a schematic block diagram of a process and system for recovering lithium values ​​from lithium-bearing silicate minerals (such as spodumene), converting the recovered lithium values ​​to a blend of lithium nitrate and lithium oxide, and then subsequently converting the blend to lithium metal. In FIG. 1, the overall process is divided into four "blocks" as follows: 1. Digestion of spodumene, etc. with nitric acid to produce pure lithium nitrate; 2. Partial decomposition of pure lithium nitrate to lithium oxide and nitrogen oxides; 3. Conversion of the nitrogen oxides to nitric acid for reuse in the digestion stage of block 1; and 4. Conversion of the lithium oxide / lithium nitrate blend to lithium metal. [Diagram 2] FIG. 2 covers and details blocks 2 and 3 of FIG. 1 and is a schematic flow diagram showing how pure lithium nitrate crystals are converted into a blended lithium nitrate and lithium oxide product, and how the gases (oxides of nitrogen and oxygen) from the thermal decomposition of lithium nitrate are reconstituted to form nitric acid that can be used throughout the process (e.g., digestion in block 1). [Diagram 3] FIG. 3 covers and details block 4 of FIG. 1 and is a schematic flow diagram illustrating a more specific embodiment of the production of lithium metal from a blend of lithium nitrate and lithium oxide. [Figure 4] FIG. 4 is a schematic diagram depicting a more detailed depiction of an embodiment of a reduction reactor for producing lithium metal from a blend of lithium nitrate and lithium oxide. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0073] In the following detailed description, references are made to the accompanying drawings, which form a part of the detailed description. The exemplary embodiments specifically described and illustrated in the drawings are not intended to be limiting. Other embodiments are contemplated without departing from the spirit or scope of the subject matter disclosed herein. As generally described herein and shown in the drawings, other modifications may be made. The aspects of the present disclosure shown on the surface may be arranged, substituted, combined, separated and / or modified in a wide variety of different configurations. It will be readily understood that various configurations can be designed, all of which are contemplated by the present disclosure.

[0074] The particular process described herein involves the blending of lithium oxide with lithium nitrate. The following detailed description will be used to illustrate the concept of the present invention. This new blend is called "Nitrolox." The products can be derived from a wide range of primary lithium-containing feedstocks, including: The minerals include, but are not limited to, hard rock (silicate) minerals, the so-called "lithium Lithium-rich brines, certain clays, and even mineral jasmines found in the Li-Triangle Dalit is one example.

[0075] First, the detailed description below covers each of the following methodologies: 1. The major class of naturally occurring lithium-rich minerals, namely, the metal silicates ( (including mica and clay, each of which will be described separately) and from brine to produce pure lithium nitrate. Method of manufacture; 2. A method for preparing the preferred blend of lithium oxide and lithium nitrate; and 3. Adjusting both the cathode and anode materials of a lithium battery, as well as lithium metal Overview of the unique use of blends for explained.

[0076] [1. Production of pure lithium nitrate from lithium minerals] Lithium nitrate is the first product of all processes described below. Lithium nitrate enables the production of convenient and economical lithium oxide (lithia). As described in WO2017 / 106925 (i.e., US10,131,968 and CN106906359), lithia is an ideal starting point for the production of pure and marketable lithium chemicals (including hydroxides (LiOH·H2O) and carbonates (Li2CO3)). - Lithium calculations are usually expressed in terms of lithium carbonate equivalent or LCE, and elemental lithium in the industry. In the future, lithium metal is expected to become a preferred material for the anodes and alloying of a new generation of lithium batteries. For example, lithium-aluminum alloys are preferred in the aerospace industry and other applications where lightweight combined with high strength and heat resistance are important attributes.

[0077] <A. Lithium nitrate from hard rock (silicate) minerals> The applicant of this application has disclosed in WO2017 / 106925 (equivalent to US10,131,968 and CN106 906359) a process for recovering lithium valuable substances from lithium-containing silicate materials. Such materials include spodumene (LiAl Si2O6) of hard rock minerals, and / or various lithium-containing silicate minerals, although not limited to, such as petalite (LiAlSi4O of the mineral 10 ​​​​​and eucryptite LiAlSi Throughout this specification, the term "spo" refers to minerals. Any and all references to "lithium-containing silicate minerals" are to these other lithium-containing silicate minerals. should be construed to include

[0078] In WO2017 / 106925, nitric acid is used to digest activated spodumene. By using it, you can avoid purchasing expensive and dangerous chemicals such as sulfuric acid and sodium carbonate (soda ash). This avoids the need to consume the same amount of water as in WO2017 / 106925. The process involves the use of sodium sulfate, or gypsum or analcite ( This avoids the purification of unwanted by-products such as nitrile (anarcime). The acid allows for a "closed" process, i.e., once consumed in the digestion process, the nitric acid can be It can be almost completely reconstituted and recycled. The process disclosed in 06925 may involve minimal processing steps.

[0079] The process disclosed in WO2017 / 106925 involves the use of pretreated silicate minerals. The process involves mixing the mixture with nitric acid (a leaching agent). Lithium values ​​in silicate minerals are dissolved from the silicate minerals by using lithium nitrate. The method further comprises subjecting the sintered material to a leaching process having conditions such that tungsten is formed.

[0080] In WO2017 / 106925, typically, the pretreatment of silicate minerals is carried out by calcination or the like. In this case, the heat treatment may include a process for obtaining a spodumene having a higher molecular weight than that of the naturally occurring α-spodumene. The temperature of a solid is raised to a level sufficient to bring about a phase change (to convert it to the more reactive beta form) It is said that it is acceptable to increase

[0081] As part of the leaching process, the pretreated silicate minerals are mixed with a stoichiometric excess of nitric acid. The blend may be subjected to a digestion process. The digestion process may be carried out using one or more stages. The digestion can be carried out in a digestion reactor (e.g., an autoclave) in which the silicate mineral is digested. The process can be carried out under conditions such as to convert the lithium values ​​in the product to soluble lithium nitrate.

[0082] The desired digestion reaction can be expressed as follows: LiAlSi2O6 (spodumene) + HNO3 (nitric acid) → LiNO3 (lithium nitrate) +LiAlSi2O5(OH)(pyrophyllite) 1)

[0083] Naturally, other impurities in the pretreated spodumene are the alkali metals sodium and and potassium, aluminum, iron, other transition metals, and alkaline earth metals (calcium and magnesium) and phosphate ions, which are then converted to various degrees of It is solubilized.

[0084] In WO2017 / 106925, the product of the leaching process is lithium ions and other The aqueous phase contains some soluble cations and anions, the remaining free nitric acid and water, and lithium. The slurry is composed of an insoluble phase which represents the remaining spodumene concentrate from which the spodumene content has been substantially removed. This slurry or paste is diluted with process water to form a solid. The solution is sent to a liquid separation system where the insoluble solids are separated from the solution and washed to recover lithium values. The purified lithium-rich pregnant solution is then obtained.

[0085] This pregnant liquor is highly acidic due to the presence of residual free nitric acid. The latter is boiled to concentrate and distill most of the free nitric acid and water, the former being further treated in a digestion reactor. The latter is recycled to the process water.

[0086] As the boiling continues, the acidity (pH) of the pregnant liquor is maintained at a constant level, and the alkalinity of the pregnant liquor is reduced. The aluminum value will hydrolyze automatically to form an aluminum hydroxide precipitate, and at the same time The resulting nitric acid is removed by boiling. 2Al(NO3)3+6H2O→Al2O3·3H2O+6HNO32)

[0087] The insoluble aluminum hydroxide is separated by filtration and further purified, inter alia, to obtain a more pure aluminum hydroxide. A pure alumina product may be produced. The concentrated solution, the filtrate, is still slightly acidic. Then, by adding an appropriate amount of lithium oxide, hydroxide, or carbonate, the pH can be adjusted to approximately These are all approximately neutral to slightly alkaline in various embodiments of the process. It may be produced downstream.

[0088] As a result, additional lithium nitrate is formed, but most of the free nitric acid is initially removed from the pregnant liquor. Lithium-based alkalines are removed by distillation and must be recycled in this way This amount is comparable to the amount required to neutralize all of the free nitric acid originally present in the untreated filtrate. The total will be much less.

[0089] These reactions take place in stirred tanks or continuous such tanks. WO2017 Although not disclosed in / 106925, once the pregnant liquor is fed into one or more tanks, Fine crystal seeds of alumina trihydrate can be obtained and the contents of one or more tanks can be The pH was kept neutral to slightly alkaline by controlling the addition of further lithium hydroxide. This allows the remaining alumina values ​​to grow and precipitate on the alumina seeds. . 2Al(NO3)3+3H2O+6LiOH→2Al2O3·3H2O+6LiNO3 3)

[0090] Although not disclosed in WO2017 / 106925, the contents of one or more tanks The water is circulated through a hydrocyclone or similar bank and the underside of the hydrocyclone is The coarse fraction of alumina crystals can then be removed by the known solid-liquid separation. It is separated from the pregnant liquor by processes (such as washing and dehydration) to produce pure crystalline aluminium. The overflow from the hydrocyclone bank is The residual fine powder content of alumina trihydrate further precipitates this compound by crystal growth. The process can be repeated in one or more tanks to serve as nuclei for the This is called "Ostwald ripening". The final over from one or more tanks The flow is a liquid that is essentially free of suspended solids.

[0091] This "solids-free" solution is mixed with additional lithium hydroxide (formed by digesting lithium oxide). The magnesium value present as nitrate in this liquid is converted into insoluble Raise the pH to a level where it precipitates as magnesium hydroxide (the mineral brucite). Mg(NO3)2+2LiOH→Mg(OH)2+2LiNO34)

[0092] Then, the carbonate of another alkali metal (e.g., sodium or potassium) or or lithium carbonate (or additional lithium hydroxide with appropriate proportions of carbon dioxide) Add an appropriate amount of to precipitate the remaining calcium values. Ca(NO3)2+Li2CO3→CaCO3+2LiNO35)

[0093] This liquid, which contains calcium and magnesium values ​​as suspended solids, is sent to purification. These settle as underflow leaving the clarified overflow. The condensed overflow is sent to a holding or storage tank and the underflow is sent to a centrifuge. The resulting mixture is then sent to a solid-liquid separator to recover the insoluble solids and wash the remaining lithium-rich liquid. The filtrate / concentrate is returned to the clarifier feed.

[0094] This purified overflow is not included in the original spodumene concentrate as an impurity in the system. The alkali metals sodium and potassium, as well as small amounts of the rarer rubidium and cesium The lithium nitrate solution is essentially free of other cations, except for Alkaline earth elements, aluminum and transition metals are virtually absent, and the phosphate ion is 1 million. It is only detectable at one-third the level.

[0095] In certain embodiments of WO2017 / 106925, the currently purified lithium nitrate The solution is further concentrated and then crystallized to form higher purity solid lithium nitrate LiNO3. The first crystallization step may be performed using an evaporator / crystallizer. 2017 / 106925 to obtain pure dry crystalline lithium nitrate product and other alkali A process by which metal nitrates (i.e. sodium and potassium) can be separated from the residual solution rich in is also outlined. Such high-purity solid lithium nitrate LiNO3 can be used as a feedstock for the thermal decomposition process as disclosed herein and described in detail with reference to FIG. 2. formed.

[0096] <B. Lithium Nitrate from Lithium-Rich Brines> Lithium is present in certain brines of salt flats (salars) known as the lithium triangle in South America. In such brines, lithium exists as ions, typically at a concentration of about 0.1%, and in some cases up to 0.4%. Other cations are mostly present in high proportions as sodium and potassium, and magnesium and calcium are also present in various amounts. The most abundant anions are chloride and sulfate, mainly chloride, but the concentrations and proportions of all species vary not only between salt flats but also within individual salars. Therefore, the following detailed description of the salt flats should be understood as essentially general.

[0097] The general method of treating (purifying) these brines to recover lithium valuable substances is to first use a submerged pump to extract the brine from the characteristic cracks and other cavities of the solid salt mass located about 40 meters above the salt flat. Below this depth, there are generally no cracks. From this depth to the bottom of the salt flat, typically encountered is essentially impermeable rock salt (sodium chloride containing various concentrations of potassium chloride and gypsum). The submerged pump transfers the brine to a dry pan formed on the surface of the dry hard rock bed of the salt flat and evaporates the water in an environment similar to a sunny desert. As solar evaporation progresses, various salts crystallize. ​​​​​​​​​​​​​​To separate one reasonably pure crystallized salt in one pan, the brine is poured from the pan into The salt is then pumped into the pans one after the other, and the next salt is concentrated (by natural evaporation) and crystallized. It is kept in a particular pan long enough to be qualitatively excluded.

[0098] The first to crystallize are the common salts NaCl and / or the sparingly soluble gypsum (CaSO 4·2H2O) is the most common.

[0099] The remainder of the cations present are primarily a blend of potassium, magnesium, and lithium. The anion is mainly chloride. When magnesium is present in high concentrations, it becomes sulfate and This can be problematic because both chlorides are very soluble in aqueous solution. Additionally, magnesium may be precipitated as insoluble magnesium hydroxide. Calcium is added to the saltwater, as shown in the reaction below. MgCl2+Ca(OH)2→Mg(OH)2+CaCl26)

[0100] If the concentration of sulfate ions is still high, the calcium-containing solution added according to reaction 6) First, more calcium can precipitate as more gypsum. MgSO4+Ca(OH)2+2H2O→Mg(OH)2+CaSO4·2H2O 7)

[0101] Otherwise, calcium may be removed using sodium carbonate (soda ash). Sodium carbonate precipitates calcium as insoluble carbonate, adding more sodium to the brine. Um is added, resulting in table salt. CaCl2+Na2CO3→CaCO3+2NaCl 8)

[0102] It is then further concentrated by solar evaporation to produce potassium chloride (potash), a valuable product. ) crystallizes in another evaporation pan. Alternatively, Chilean saltpeter (sodium nitrate) is readily available. In this case, it is leached with water, separated by solid-liquid separation to remove the insoluble solids, and then added to concentrated salt water. When the blend is thermally evaporated at its boiling point, the following reaction occurs: KCl+NaNO3→NaCl+KNO39)

[0103] Since table salt is one of the least soluble salts, the reaction proceeds to the right, producing potassium nitrate, a valuable fertilizer. The remaining salt water is then cooled, for example by vacuum cooling, and collected. Typically, in Chilean saltpeter deposits, about 10% of the sodium ions are calcium ions. These are replaced by potassium ions, which also crystallize as additional potassium nitrate.

[0104] What remains is a residue that is highly enriched in lithium and has chloride as the predominant anion. It is essentially a solution of concentrated lithium chloride with various residual salts present as trace impurities. A concentrated solution remains.

[0105] The usual process involves heating lithium-rich brine to over 70°C and then adding soda ash to the mixture. , which precipitates lithium as poorly soluble lithium carbonate, the primary lithium product. The product may be further purified by various processes known to those skilled in the art, including recarbonation, etc. Overall recovery of lithium can vary and typically varies depending on the source brine. This is 50-80% of the lithium that was previously present.

[0106] Previous accounts have focused on the salt flats of the Lithium Triangle in South America, particularly the important Atacama Desert in Chile. It is representative of the current technology used in Shiobara. We emphasize once again that the above is a very simplified description of the general process, The order of evaporation and crystallization may vary depending on the original composition of the brine and operating preferences.

[0107] The following description represents a departure from the known art. A process for producing pure crystalline lithium nitrate from a source.

[0108] The starting material for the process is a concentrated solution of lithium chloride with residual amounts of other salts (mainly table salt). (i.e. the residual solution from which potassium nitrate has crystallized). The production of potassium nitrate is Typically, when processors have ready access to Chilean saltpeter (i.e., major Chile-based saltpeter processors), The only option available to saltpeter processors that have immediate access to Chilean saltpeter supplies is It should be noted that:

[0109] It is essentially a replica of the potassium nitrate manufacturing process, extracting as much potassium-containing salt as possible from the brine. After the value is recovered, Chilean saltpeter is added to the lithium chloride-rich brine, and the blend is boiled. When thermally evaporated at a point, the following reaction occurs: LiCl+NaNO3→NaCl+LiNO310)

[0110] Here too, the salt crystallizes, and the residual lithium nitrate-rich liquid is washed away to remove the lithium nitrate. A concentrated solution remains.

[0111] The lithium nitrate solution is cooled, for example by vacuum cooling, to obtain pure lithium nitrate crystals. The crystals are separated by a conventional solid-liquid separation process, such as by a suitable filter centrifuge. Therefore, it can be removed. The remaining brine (i.e., filtrate / concentrate) is recycled. If desired , for example, additional crystallization, removal of impurities from the pregnant solution using ion exchange resins, drying of the crystal mass , and lithium nitrate can be further purified by various methods such as dissolution in a mild polar organic solvent in which lithium nitrate dissolves but nitrates of other alkali metals do not dissolve ( see below). As other purification methods, methods known to those skilled in the art can be used.

[0112] <C. Lithium Nitrate from Other Minerals (Mica, Clay, and Jadaraite)> Lithium is present in other minerals including part of the mica group, especially in amblygonite ( Li,Na)AlPO4(F,OH), lepidolite K(Li,Al,Rb)3(Al, Si)4O 10 (F,OH)2, and tinwaldite KLiFeAl(Al,Si3)O 10 (F,OH)2. Also, lithium can be present in certain clays formed by partial weathering of mica minerals such as hectorite Na 0.3 (Mg, Li)3Si4O 10 (OH)2. Another third category of minerals is the borosilicate mineral jadaraite Li NaSiB3O7OH. This can also be expressed in the form of Na2O·Li2O·(SiO2)2·(B2O 3)3·H2O, and it is named after the nearby town of Jadarl in Serbia and was first defined as a unique mineral in 2006. Jadaraite is expected to be an important future source of lithium. Also, it is expected to be a source of boron, which contains nearly five times the amount of boron as lithium, greatly enhancing the value of this resource. In the prior art search, treatment methods are being investigated, but nitric acid ​ There is no known way to use it.

[0113] Surprisingly, we found that all of these minerals were virtually soluble in hot nitric acid. Ta.

[0114] (Amblygonite, Lepidolite and Zinnwaldite) These are relatively soft minerals that are susceptible to leaching with mineral acids such as nitric acid. In one embodiment, calcination is not required, and calcination is generally not required. Rolls crush the mineral, essentially peeling off the "sheets" that characterize mica. This improves the acid permeability and allows the metals to be separated as metal nitrates (i.e., when using nitric acid). Increase extraction of.

[0115] In one particular embodiment, the lepidolite is finely ground, optionally beneficiated, and then To recover lithium values ​​from calcined spodumene, a method similar to that described above was used. React with nitric acid by the method described above. Lithium, sodium, potassium and rubidium (potassium A similar rare alkali metal that occurs in lepidolite in various but generally low concentrations Most of the nitrates are converted to nitrates, and the impurities of aluminum, calcium, and magnesium are removed. Some of the magnesium and transition metals are also converted to nitrates. Insoluble solids are removed and excess nitrate is removed. The pregnant liquor remaining after the acid and most of the water have been distilled off is then subjected to the techniques described above for calcined spodumene. When fluorine goes into solution (as fluoride ions), it is converted into poorly soluble fluoride. High fluorine levels are problematic because lithium tends to be removed as lithium fluoride. Phosphorus values ​​are produced from insoluble tricalcium phosphate (the mineral apatite). It precipitates as

[0116] Pyrolysis of lithium nitrate followed by recovery of the nitrogen oxides and oxygen produced as off-gas However, it is possible to recover nitric acid by combining these with water and additional oxygen (from the air). However, other alkali metals, namely sodium and potassium (and rubidium), Of these, potassium is generally the most abundant. Lithium values ​​can be easily converted to other alkali metals. There are several options for separating the nitrile from the nitrile. One option is to use a blend of alkali metal salts. Dry the material and dissolve lithium nitrate but not other alkali metal nitrates. The first step is to leach the lithium values ​​using a mild polar solvent that is not toxic. Many polar hydrocarbon solvents (e.g. acetone) are highly flammable and therefore unsuitable for this application. However, highly chlorinated simple hydrocarbons such as chloroform (trichloromethane) is highly safe and, as a result, can be used appropriately to dissolve and separate lithium nitrate. The reactive solvent was removed from the lithium nitrate (and any other components that may be present) using vacuum distillation to recycle the solvent. It can be recovered from other solids (potentially other solids).

[0117] Once lithium nitrate is separated, the residue (mainly a blend of sodium nitrate and potassium nitrate) is Nitrates of potassium are valuable as fertilizers, especially when they contain potassium as the main component. Um is the source of the three major nutrients for plants: potassium (K), nitrogen (N) and phosphorus (P). It contains not one but two of these, making it more valuable than potassium chloride or sodium nitrate. It is a high-value fertilizer (widely used in drip irrigation systems).

[0118] Can be used when sources of lithium chloride are readily available (e.g., in salt flat environments). In one embodiment of the lepidolite treatment, a mild polar solvent is used to remove lithium valence. Before leaching the material, the following reaction may be carried out. In this regard, we have arrived at reaction 10) For the treatment of salt, refer to the process described above. The following reaction, similar to reaction 10, It can be used as follows: LiCl+NaNO3 / KNO3→Na / KCl+LiNO310')

[0119] The resulting salts of NaCl and KCl can be separated from the LiNO3, and the latter is sent to the pyrolysis stage. It is further purified before being reused.

[0120] However, the nitrates of sodium, potassium, and (if present) rubidium are in the form If the nitric acid is not recovered by the procedure described in reaction 9), the total Furthermore, as mentioned above, these alkali metal nitrates do not disappear even when heated. It does not decompose in the same way as lithium nitrate. However, the decomposition of nitrates by this mechanism In addition to the losses, other losses of nitrates (and therefore nitric acid) from the system occur when ammonia is used. This is a well-known process, especially for those who have been involved in the production of nitric acid by the Ostwald process. According to the process described above, the catalyst is heated in air with a suitable catalyst (e.g., platinum gauze). This can be supplemented by the combustion of ammonia, which is promoted by the In this regard, 1 ton of ammonia produces 6 tonnes of potassium nitrate. Rubidium is thought to exist only in low concentrations. Since potassium behaves similarly to potassium and is not toxic to plants (although fertilizer It has no commodity value, and does not need to be separated from potassium nitrate unless the concentration is particularly high. In such cases, there may be an economic case for additional recovery methods.

[0121] (Jadalite) Nitric acid is the basis for a more efficient process for producing lithium nitrate from jadarite It is also possible to form jadarite mineral by crushing it and reacting it with hot nitric acid. LiNaSiB3O7(OH)(jadalite) + 2HNO3(nitric acid) + 3H2O → Li NO3 (lithium nitrate) + NaNO3 (sodium nitrate) + 3H3BO3 (boric acid) + S iO2 (Silica) 11)

[0122] The nitric acid concentration cannot exceed the solubility of boric acid. This is due to the decomposition temperature near boiling water. In saline, it is approximately 24 grams per 100 mL.

[0123] The product from the leaching reactor is filtered to remove silica and other insoluble impurities and to remove boron. This leaves a clear solution of the acid and the highly soluble nitrates of sodium and lithium. When the solution is cooled, for example by vacuum cooling, the boric acid precipitates in the form of transparent, colorless crystals. In one embodiment, these crystals are separated by decanting or centrifuging. The separation and cleaning is carried out by using a screen bowl variant of the machine.

[0124] Separating lithium nitrate from its sodium counterpart by crystallization from aqueous solution poses challenges because both are highly soluble in water and have relatively steep solubility curves. However, as explained for lithium-rich mica, sodium nitrate is Lithium nitrate is insoluble in the polar liquid, but lithium nitrate dissolves in this liquid, so the two can be separated. can.

[0125] In one embodiment, the residue from the crystallization of boric acid is evaporated to dryness, ground into a powder, and thoroughly Blend with acetone to dissolve the lithium nitrate. Then add the insoluble sodium nitrate. In one embodiment, a filtration centrifuge is used to filter or centrifuge the lithium nitrate. This solution is distilled under vacuum to leave behind sodium nitrate mass and acetone. The acetone is recovered and condensed in an air-cooled condenser for reuse of the tonnes.

[0126] Acetone solvent can form explosive mixtures with alkali metal nitrates. Other solvents that are as polar as acetone but are not flammable, such as trichloromethane, Highly chlorinated hydrocarbons such as benzene and toluene can be used.

[0127] Residual sodium nitrate may be used as fertilizer. Alternatively, lithium-rich (salt flats) Similar to the process for producing lithium nitrate from brine, lithium chloride must be available within reasonable transport distance. If a source of lithium nitrate is available, this can be used in the process embodied in reaction 10 above. It can be converted to Um.

[0128] 2. Preparation of Lithium Oxide and Nitrate Salt Blends for Battery Cathode Lithium nitrate is used by battery manufacturers and lithium / transition metal oxide (or hydroxide) , carbonates or nitrates) and other companies involved in the production of related compounds for cathodes Such a cathode has the following general composition: (In a battery cell, when the cathode is fully discharged). LiMO2: where M is a transition metal or blend of metals (cobalt, nickel, manganese, etc.). of cancer, iron, chromium and titanium, and occasionally of aluminium (although not of the transition elements). These metals have an oxidation state of +3. Li2M'O3: where M' is a transition metal or blend of metals (cobalt, nickel , manganese, chromium and titanium, etc.), The metal has an oxidation state of +4

[0129] These compounds may be finely divided oxides or salts (which may be sulfates, chlorides or nitrates). The titanium compound (usually a carbonate or hydroxide) is blended in the correct ratio to form a compound. It is made by heating the blend, typically in stages, until one or more of the ingredients melts. This allows, for example, the crystal structure of minerals (spinel, olivine, perovskite, to a compound with the desired structure that mimics one zeolite or another The transport and rearrangement of lithium ions becomes possible (i.e., lithium ions can enter and leave the crystal structure). Typically, these blends are made on a batch basis. Treatment (e.g., holding at 850°C or higher for 10 hours or more) The details of how these compounds are made are closely guarded trade secrets. The above description is general in nature.

[0130] The process for making such cathodes involves melting one or more components to form a conductive It begins with forming a medium having at least one component with a lower melting temperature. It is advantageous to decompose the oxides at relatively low temperatures and then heat the oxides in water or carbon dioxide. It is advantageous to use a raw material that can minimize carbon generation, which is achieved by using a temperature This is because as the temperature drops, the materials may recombine.

[0131] When lithium was first supplied to battery manufacturers, it was mostly in the form of lithium carbonate. Lithium carbonate melts at a temperature of about 725°C and melts at about 1, It does not decompose (become lithium oxide) until it reaches 300℃. Lithium hydroxide is heated to about 460℃. It melts at 300°C and decomposes (to lithium oxide) at 925°C, making it popular with battery manufacturers. Lithium oxide itself is also highly fire-resistant, and can melt at temperatures above 1,450°C. As a result, the reaction required to form the lithium / transition metal cathode compound is For the reaction to occur, another compound with a lower melting point than lithium oxide is required.

[0132] Lithium nitrate may have a distinct advantage in this respect. In the case of pure lithium nitrate: It melts at a relatively low temperature, about 260 °C. Above these temperatures, lithium nitrate is transparent. Lithium nitrate becomes a fluid, electrically conductive liquid. and may be further heated to facilitate the synthesis of the transition metal compounds required for the production of a given cathode material. Lithium nitrate decomposes at only about 600°C (reaction 12) to form lithium oxide and nitrogen. It produces elemental oxides and free oxygen. 4LiNO3 → 2Li2O + 4NO + 3O2. 12)

[0133] Once decomposition is complete, the initial 1 kilogram of lithium nitrate (in pure, anhydrous form) , only 0.22 kg of lithium oxide is obtained, but it also contains the same amount of lithium. That is, lithium nitrate has an elemental lithium content of 10% by weight, but pure lithium oxide The elemental lithium content is 46% by weight.

[0134] Of particular interest are lithium nitrate and lithium oxide, which is obtained by partially decomposing lithium nitrate. The following table lists the The results of decomposition of a quantitative amount of lithium nitrate are shown.

[0135] [Table 1]

[0136] The numbers below the line are those that are so rich in lithium oxide that they are treated as a slurry or paste. represents a composition that cannot be decomposed (i.e., at temperatures above about 260°C with more than 90% decomposition). (There may not be enough molten LiNO3 present.)

[0137] As an example (shown in bold in the table above), lithium nitrate is decomposed by 75% into lithium oxide. At this point, the originally nitric acid is heated above its decomposition temperature until it is dissolved (column 2). All the lithium contained in the lithium was mixed with 50% lithium nitrate and 50% lithium oxide. The mixture is concentrated into a mass of lithium nitrate that can be handled as a paste (i.e., lithium nitrate). (i.e., about 260°C, preferably about 300°C). The weight of 50% lithium nitrate and 50% lithium oxide is This is slightly more than one-third of what it was when it was in the form of a granular material (column 3). The lithium concentration per unit volume has almost tripled (from about 10 to about 28%, column 4). ).

[0138] In the case of paste, the method used to convert materials such as molten salt mixtures into prills (e.g. The blend is then prilled and pelletized in a prilling tower. The material can be easily converted into either pellet or flake form. Easier to handle and store (e.g. solids can be stored in 200 litre sealed drums) The high lithium content of such blends means that lithium carbonate (1 Lithium hydroxide monohydrate (16% Li) and lithium hydroxide monohydrate (9% Li) have been shown to have transportation advantages over lithium hydroxide monohydrate (16% Li). It means.

[0139] 3. Production of lithium metal from nitrox blends In the process disclosed herein, lithium nitrate is advantageously and uniquely produced directly from lithium nitrate. The lithium oxide produced by the reaction can be easily converted to lithium metal by a process such as carbothermal reduction. Importantly, the inventors were able to convert magnesium oxide to magnesium by carbothermal reduction. The equipment and systems developed to produce magnesium metal have been adapted to the production of lithium metal. This is because existing methods for producing lithium metal are highly sophisticated. The molten mixture of anhydrous lithium and potassium chlorides was electrolyzed at a temperature of about 450°C. This is important and highly valuable, given the complex and expensive way of It is also an innovation that has been a major step in the development of such existing methods (i.e., high purity anhydrous salts). The production of lithium carbide also requires complex processing.

[0140] The carbothermal reduction process produces many important metals, notably iron and steel, but also manganese. , which is the basis for the production of ferrosilicon, pure silicon, and (indirectly) magnesium metal. For example, the Kroll process for producing metallic titanium (using magnesium metal as a reducing agent) (The system uses

[0141] More importantly, the inventors have discovered that the process was originally developed for the production of magnesium metal. By applying the technology, lithium nitrate and lithium oxide can be directly produced by direct carbothermal process. One such example is in U.S. Patent 9,090 ,954, which contains magnesium oxide and some form of carbon (e.g. For example, graphite, petroleum coke, or coal-derived coke) are blended into briquettes. This is then heated in a furnace (either induction or electric arc heating can be used) at about 2.0 A process is disclosed in which the oxide is electrically heated to a temperature that can reach 00°C. The reaction proceeds as follows: magnesium is reduced to magnesium metal and carbon is oxidized to carbon monoxide. A reversible reaction like this occurs. MgO+C→M+CO 13)

[0142] To prevent the reaction from reversing (from right to left), high-temperature steam (magnesium steam and Carbon monoxide) is supersonic expanded through a converging-diverging (Laval) nozzle and flash cooled. This allows the gas to expand and cool so quickly that the reverse reaction does not occur very often. The process described in US 9,090,954 has been known to cause nozzle degradation and clogging. Keep the nozzle in place to prevent impurities from condensing on the exposed nozzle surface, which can cause Equipment for keeping the temperature at a constant level is defined.

[0143] Pure lithium oxide (essentially produced by the processes disclosed herein); An essentially mineral-free form of carbon (e.g., certain grades of petroleum coke, or ash) Coke made from natural coal with low levels of ash, or from coal that has first been chemically deashed By relying solely on ultra-clean coal, the process 4 and US 4,200,264, the prior art, e.g. Hiro These processes include equipment similar to that in US 9,090,954. but has no mechanism to ensure that the nozzle remains sufficiently heated. .

[0144] Furthermore, lithium metal by means of US 4,147,534 and US 4,200,264 In the case of carbothermal production, condensable gases tend to pass through the nozzle and condense on its exposed surfaces. There should be very little mineral available and the risk of nozzle degradation should be minimal. The inventors have found that lithium metal is advantageously a common It remains liquid over a wide range of temperatures, including under atmospheric conditions. This allows it to be used in the flow of gases such as carbon monoxide. Lithium metal can be rapidly separated from the

[0145] In one embodiment, this rapid separation is achieved using one or more cyclone separators operating in series. In addition, the use of banks of The carbon monoxide gas produced can itself be used as fuel, which is achieved by using lithium-containing silicate This includes use as a partial replacement for natural gas used to calcinate mineral ores. do.

[0146] The reaction for lithium oxide is: Li2O+C→2Li+CO 14)

[0147] Additionally, the inventors believe that the Nitrolox blend makes it easier to produce lithium metal. We recognized that this could serve as the basis for a methodology.

[0148] The challenge with the carbothermal production method described so far is maintaining the furnace temperature at around 2,000°C. The only satisfactory method is electrical heating, either by induction or by electric arc. Since reaction 14) is a strongly endothermic reaction, there is enough electrical energy to move reaction 14) to the right. Considering the energy consumption and the inevitable losses due to the high temperature, the total reduction process Seth will be expensive.

[0149] Nitrox essentially contains energy in the form of the nitrate ion. Lithium oxide Nitroxbrene to provide part of the energy that influences the carbothermal reduction of Reactions involving the nitrate portion of nitrolox are as follows: 2LiNO3+6C→2Li+6CO+N215)

[0150] The reaction between lithium nitrate and carbon is highly exothermic. This is the same principle as gunpowder (i.e. (The use of potassium nitrate instead of lithium nitrate.) Nitrolox blends. Reactions 14) and 15) may occur in parallel. Reaction 14) is, as mentioned above, , is strongly endothermic, and reaction 15) is strongly exothermic. Therefore, reaction 15 releases The energy gained can offset part of the energy needed to drive reaction 14). The energy required to drive reaction 14) is usually provided in the form of electricity, so would be a big savings.

[0151] Comparing reaction 14) and reaction 15), the latter produces substantially more gas than the former. The inventors have found that a large amount of gas results in a limited increase in plant size. However, under the conditions in the reactor, the gas is non-reactive. This allows for improved process control and the use of Nitrolox and Ashless, which are fed separately to the furnace. For a description of a plant suitable for the production of lithium metal using similar carbon, see Figures 3 and 4. are provided in accordance with the

[0152] Reactions 14) and 15) produce lithium metal vapor and gaseous by-products. The process is completed by supersonic expansion through a nozzle ( For example, such a method may be used via one or more banks of cyclone separators (operating in series). The resulting lithium metal can be recovered and then further purified (i.e. In order to obtain the required degree of purity of lithium metal, another downstream process, e.g., lithium (e.g. by vacuum distillation, which is a common industrial method of further purifying the metal).

[0153] This results in, for example, lithium oxide, lithium nitride, carbon, and / or other resistant The ignitable solid material passes through a Laval nozzle into the cyclone, where it is filled with lithium vapor and carbon monoxide. Even if they are brought in together with other substances, they can be easily separated by other downstream processes (i.e., vacuum distillation, etc.) .

[0154] In this regard, lithium oxide does not melt until temperatures exceed 1450°C, whereas lithium nitride has a melting point of about 850°C, so it is necessary to use vacuum distillation to purify lithium metal into a solid. Furthermore, after such vacuum distillation (i.e., free lithium If there is any lithium value remaining as lithium nitride (after distillation of lithium metal), Simply add lithium chloride to dilute nitric acid to form lithium nitrate and ammonium nitrate. , which can be retrieved, Li3N+4HNO3→3LiNO3+NH4NO316)

[0155] Hereinafter, the above-mentioned process for producing lithium metal and The system will now be described in more detail.

[0156] <Overall process (production of nitrox and lithium metal – Figure 1)> Referring now to FIG. 1, nitrox (i.e., lithium nitrate and nitrile) can be produced from spodumene. The entire process for producing lithium metal (a blend with lithium chloride) and lithium metal is a process The whole process is shown diagrammatically as a block diagram. It consists of four "blocks" 1-4. It has been shown that this has been achieved.

[0157] In process block 1, (α) spodumene is calcined in a calciner, for example, using natural gas. Optionally, the calciner can also be used to activate lithium metal. The recycled fuel gas containing carbon oxides may be used in addition. The activated (β)-spodumene is sent to a digestion stage (e.g., an autoclave) and heated at high temperature. The digestion is carried out by contacting the digested material with nitric acid under high pressure. The nitric acid for the digestion stage can be produced in a nitric acid production plant. (Block 3 of the overall process). The feedstock for the nitric acid production plant is the digestion stage and lithium nitrate. Volatiles / off-gases from each of the pyrolysis stages (Block 2 of the overall process), as well as a supplementary stage (e.g., a catalytic combustion stage of ammonia with air - see Figure 2 herein) This may include volatiles / off-gassing from

[0158] In the digestion stage of process block 1, β-spodumene is leached with nitric acid and lithium nitrate is Lithium nitrate is isolated and purified from the residue of β-spodumene digestion. However, this also involves a purification step, the lithium nitrate crystallization step, which results in a relatively pure nitrate. The lithium oxide is produced and is ready for the pyrolysis stage (process block 2).

[0159] In process block 2, relatively pure lithium nitrate is pumped to a holding (preheating) vessel where it is The material is heated to a molten state in a process fluid (e.g., by a hot process fluid). The load on the decomposition reactor is relieved. The molten pure lithium nitrate is then pumped into the pyrolysis reactor. (typically an electrically inductively heated or externally heated reactor) in which the reaction mixture is heated for a predetermined period of time. Lithium nitrate is heated above its decomposition temperature, and a portion of the lithium nitrate is decomposed into lithium oxide. The partial decomposition of lithium nitrate produces gaseous nitrogen oxides. A blend of molten lithium nitrate containing solid crystals of lithium is produced.

[0160] In addition, in process block 2, a blend of lithium nitrate containing lithium oxide is Extract from the partial decomposition reactor and immediately bring the temperature below the decomposition temperature of lithium nitrate (e.g., with a heat exchanger) If the pyrolysis reactor is pressurized, the product (a solution containing solid lithium oxide) is The resulting product is a slurry of nitrox. Lithium nitrate slurry / paste (i.e., molten lithium nitrate containing solid lithium oxide) As shown in Figure 1, a portion of this slurry / paste was (as a gas) to a solids formation stage (e.g., a prill tower, etc.), where The other part is lithium metal production ( It can be sent to block 4) of the overall process.

[0161] In process block 3, volatile materials from each of the digestion and pyrolysis stages are combined and Combine, cool and install in nitric acid production plants (e.g., absorption towers or compact heat exchangers) Supplemental nitrogen oxides may be added to this combined stream. Supplemental nitrogen oxides are produced separately in a catalytic combustion reactor where ammonia is combusted in air. Nitric acid obtained from the nitric acid production plant is reused in the digestion stage of process block 1.

[0162] In process block 4, the Nitrolox blend slurry / paste is heated in a reduction furnace. Typically, when the nitrolox blend is in solid form, it is reduced to lithium metal. (i.e., cooled below the melting point of lithium nitrate via partial thermal decomposition), The nitrox blend is then remelted in a holding tank. This remelting is carried out by mixing the nitrox blend with a carbon source in a reduction furnace. Typically, carbon is essentially dissolved in ash-forming mineral matter. The carbon is fed to the periphery of the reduction furnace so as to form a downwardly sloping carbon bed. In the furnace, the lithium nitrate component reacts exothermically to remove substantially all of the lithium in the feedstock. Thermal energy to achieve a high enough temperature to reduce lithium to metal (by reaction with carbon). 3 and 4, the high temperature lithium The metal vapor, together with the gaseous by-products, is rapidly expanded by the Laval nozzle at supersonic speeds. After cooling to room temperature, they are separated from each other and the lithium metal is recovered.

[0163] Referring now to FIG. 2, process blocks 2 and 3 of FIG. 1 will be described in more detail.

[0164] <Production of lithium oxide and recycling of nitric acid (Fig. 2)> Referring now to FIG. 2, the pure lithium nitrate produced in the overall process block 1 is The anhydrous lithium nitrate crystals 21 are transferred to a liquid lithium nitrate holding tank 22. 1 via a variable speed screw conveyor (i.e. to control the process feed rate) The contents of the holding tank 22 can be transferred to the lithium nitrate storage tank 22 at a temperature above the melting point of lithium nitrate (approximately 260°C). ), typically above 300°C. The coating is made of potassium nitrate, sodium nitrate and nitrate. The electrodes contain a plurality of channels through which a blend of alkali metal salts, such as lithium oxides, flows. As detailed in WO2017 / 106925, the process for producing pure lithium nitrate The temperature of this molten salt circulation stream is in tank 22. 22. The tank 22 is maintained at a temperature higher than the temperature of the contents of the tank 22 to ensure that the desired temperature is maintained. Once in the tank 22, the lithium nitrate crystals 21 quickly melt and become clear and fluid. It becomes a liquid with

[0165] Depending on the needs of the process, the contents of tank 22 are pumped by pump 23 to decomposition reactor 2 4. If the decomposition reactor 24 is operated under pressure (i.e., the reactor 24 is In the case where the lithium nitrate is in the form of a vessel (autoclave), the pump 23 is arranged to pump the molten lithium nitrate at a pressure of about Up to a pressure of 10 bar (9 bar gauge), i.e. the operating pressure of the lithium nitrate decomposition reactor 24 The contents of the reactor 24 can be configured to be elevated to a pressure of 1000 bar. The temperature is maintained above about 600°C.

[0166] In the reactor 24, an electric induction coil 24a (shown in cross section as a schematic) is positioned within the reactor 24. However, in other forms of reactors, the temperature is maintained by electrical induction. External combustion of fuel (e.g., natural gas) to heat the vessel and its contents from outside (i.e., indirect heating) ) The temperature can be maintained by a burner.

[0167] At the decomposition temperature, the energy applied by electrical induction etc. is converted into lithium nitrate according to the reaction12) Disassemble. 4LiNO3 → 2Li2O + 4NO + 3O2. 12)

[0168] The lithium oxide takes the form of small crystals suspended in the molten lithium nitrate.

[0169] The rate at which reaction 12 proceeds is directly related to the rate at which energy, such as electricity, is input. It has been confirmed that molten lithium nitrate does not foam, but rather forms gases (nitrogen and oxygen).

[0170] From Table 1 above, it can be seen that the maximum practical conversion rate of lithium nitrate to oxide is about 80%, This corresponds to a blend of 40% lithium nitrate and 60% lithium oxide by weight. What is striking is that this blend contains the same amount of lithium nitrate as that contained in three times its mass. The main feature is that it has a large amount of lithium.

[0171] Blends of molten lithium nitrate containing lithium oxide crystals (Nitrolox slurries) The mixture (or paste) is heated to a temperature of about 600° C. in a reactor 24 (the reactor 24 is a pressure vessel). In some cases, the anhydrous lithium nitrate enters the reactor 24. The rate at which this slurry / paste exits the reactor 24 compared to the rate at which it is discharged is summarized in Table 1. As previously discussed, the extent to which decomposition of the nitrates to oxides is desired is highly dependent upon the desired degree of decomposition of the nitrates to oxides.

[0172] A portion of the hot Nitrolox slurry / paste is described further below with reference to Figures 3 and 4. As will be described in detail below, the lithium metal is shipped directly to the facility that produces it without further processing. The remaining portion of the hot Nitrolox slurry / paste (or If lithium metal is not produced on-site, all hot Nitrolox paste / slurry The melts (22, 24) are partially cooled by the heat exchanger 25. In this heat exchanger, they are cooled by the A countercurrent of salt (i.e., a blend of sodium, potassium, and lithium nitrates) is introduced to the The mixture is cooled to 300°C. This heats the molten salt blend streams in sequence and are reused elsewhere throughout the process.

[0173] The partially cooled Nitrolox slurry / paste is then pumped through pump 26. and then fed to a prill tower (not shown) where it is mixed with the raw material using equipment and systems well known to those skilled in the art. The liquid is then separated into pieces of approximately 1 to 2 mm in diameter using a vacuum oven. It falls through the prill tower, solidifies (condenses) as it passes upwards through the prill tower, and is collected in a container. For example, a 200 liter container with an airtight lid is Stainless steel drums or similar cans can be used. The dry air passing through the prill tower is Process water is used to wash away dust and other contaminants before it is released into the atmosphere.

[0174] If the reactor 24 is a pressure vessel, a pump 26 may be provided to pump the nitrolox therethrough. The pump may be in the form of a suitable positive displacement pump for reducing the pressure of the slurry / paste (i.e., The head 26 operates in reverse as a head-recovery device. This results in a pressure drop in the nitrolox slurry / paste exiting the reactor. Much of the head can be returned (e.g., directly) to the feed pump 23 or can be used for head recovery. The pressure is maintained between the head-recovery pump 26 and the supply pump 23. In either case, the resulting The partially cooled and partially depressurized Nitrolox slurry / paste is It is then sent to the prill tower.

[0175] The hot off-gas from reactor 24 is mainly composed of nitric oxide and oxygen, as shown on the right side of reaction 12). and fed to mixer 27 at a temperature of about 600° C. (optionally under pressure). In the mixer 27, the gas is mixed with gases (and optionally mist) from elsewhere in the overall process. or water in the form of steam.

[0176] Reactive nitrogen (i.e., nitric oxide (NO) and nitrogen dioxide / nitrogen tetroxide (NO2 and N2O4)), for example, due to inefficiencies in their recovery or due to the use of nitrolock To the extent that these are lost from the system due to loss of nitrate ions in the gas product. Losses of active nitrogen are compensated for. For example, anhydrous ammonia is purchased as a pressurized liquid. In that state, it is transported to the site, for example by road tanker, and the system that is familiar with the related technology is used The ammonia is then stored (optionally under pressure) until needed. Optionally, when reactor 24 operates as a pressure vessel, the anhydrous ammonia is A pressure at least equal to the off-gas pressure from reactor 24 (e.g., about 10 bar (9 bar It can be retrieved by pressing the

[0177] Ammonia can be produced by a process closely adapted to the manufacture of nitric acid according to the Ostwald process: In the ambient air, which may be compressed by air compressor 33 (e.g. in the case of pressurized reactor 24), Platinum gauze or other materials (e.g., transition metal oxides, or their hydroxides, carbonates, or react (burn) over a catalyst (which may be a suitable blend of nitrates) according to reaction 17) Forms nitric oxide. 4NH3+5O2→4NO+6H2O 17)

[0178] The temperature of the gas on the right side of reaction 17) may be on the order of 700°C. It is blended with the off-gas from reactor 24 and has approximately the same temperature, about 600°C. These are also blended with off-gas and steam from lithium nitrate production and sent to gas compressor 3. 1 can increase its pressure (for example, to about 10 bar), which also Adiabatically heat the off-gas and steam until it is at a temperature similar to the other gases entering mixer 27. It can play a role.

[0179] The resulting combined gas stream from mixer 27 is cooled in three stages. First, the gas stream is passed through a heat exchanger 28 in the form of a shell-and-tube vessel. Inside the tube is a relatively cold (initially about 150°C) alkali metal The molten nitrate blend flows through the reactor, which is heated in sequence and then partially cooled. The gas is passed through a water-cooled heat exchanger 29 (cooling water is provided by a process) before being sent to the nitric acid absorption tower 30. The tower also has tower packing. The tower is cooled by cold water circulating through tubes distributed in the Nitric acid is produced by the following reaction: 2NO+O2→2NO218a) 3NO2+H2O→2HNO3+NO 18b)

[0180] The NO produced in reaction 18b) is recycled to reaction 18a).

[0181] Typically, the nitric acid from the absorption tower 30 is used to convert lithium values ​​from lithium-rich minerals. in the fractionator for use in leaching (i.e., in the digestion stage of process block 1). It is concentrated to the appropriate concentration by distillation.

[0182] The off-gas shown exiting the top of the absorption tower 30 is composed of atmospheric nitrogen, It is a blend of some residual oxygen, as well as small amounts of water vapor and unreacted oxides of nitrogen. The exhaust gas is then fed to the inlet which passes through the spodumene calciner (i.e., process block 1). Alternatively, pressurized exhaust gas may be blended into the exhaust air supply. It may be fed to a turbine to recover energy therefrom.

[0183] The process scheme as shown in FIG. 2 and described above allows the original lithium-rich This is most closely related when the abundant mineral contains spodumene. However, the process mechanism in Figure 2 However, it should be understood that the scope of the entire process is not limited to this mineral. As disclosed, other minerals and lithium salts can be used to produce pure lithium nitrate crystals. The supplies to the plant and equipment can be configured.

[0184] <Production of lithium metal (Figs. 3 and 4)> Referring now to FIG. 3, a blend of lithium nitrate and lithium oxide (Nitrolock) The blend is prepared in a suitable recipe in a remelt / storage vessel 41 (e.g., (This may be trimmed by adding more lithium nitrate.) The container 41 has a circumference of It can be heated to temperatures of the order of 400°C using high-temperature molten nitrates circulating inside the coating. do.

[0185] The hot blend is withdrawn at a controlled rate and typically operated under pressure. The wastewater is fed to a thermal reduction furnace 40. The furnace 40 also includes an acid and alkaline cleaning process as will be understood by those skilled in the art. Virtually ash-free, derived from coal that has had ash-forming minerals removed by a process Carbon in the form of coke is also supplied. Some coals (e.g. Indonesia and New Zealand) (New Zealand) has a naturally very low ash content and is therefore chemically washed. Similarly, petroleum coke also has a very low ash content. (However, "bottom" petroleum coke falls into this category.) After the coal has been chemically de-ashed as necessary, it becomes virtually ash-free. Coal is pyrolyzed (in one embodiment) in a coke oven to drive off all volatile matter and produce a coal / Minimize the hydrogen content of the coke. Also, make it almost ash-free, preferably 0. Graphite is used as the carbon source if it is less than 5% by weight, more preferably less than 0.2% by weight. It is also possible.

[0186] Typically, the contents of the furnace 40 are heated to temperatures in excess of 1,500° C. (potentially up to about 2,000° C.). The furnace 40 is optionally equipped with a suitably positioned induction coil 43 (e.g. For example, a wall of the furnace substantially encircling the contents of the furnace 40 and surrounding the Laval discharge nozzle 42 may be provided. In another embodiment (not shown), the required temperature The carbon electrode is connected to a furnace 40 through which an electric arc is struck between the tip and the carbon briquettes. may be maintained.

[0187] The furnace 40 is designed to operate at temperatures in excess of 1,500° C. for a sustained period of time. Therefore, the furnace 40 is entirely lined with graphite or other compressed carbon bricks. In some embodiments, the feed to the furnace 40 may be in the form of only lithium oxide. lithium value or Nitrolox blends containing very small amounts of lithium nitrate In this case, the high temperature required for lithium reduction is generated by electrical energy supplied via the induction coil 43. In another embodiment, the nitro gas supplied to the furnace 40 may be sustained by When the cobalt blend contains a higher percentage of lithium nitrate, the interfacial tension between the lithium nitrate and the carbon increases. The energy released from reaction (Reaction 15) is supplied to lithium as lithium oxide only. This can replace part of the electrical energy used when

[0188] In the embodiment of FIG. 3, additional lithium nitrate is added to the nitrolox blend in storage container 41. may be added to the container (i.e., the contents of the container 41 may be constantly monitored to provide a substantial but controlled (It can be ensured that lithium nitrate content is present in the furnace feed).

[0189] During operation, essentially uniform size particles were produced without the use of binders, as shown in Figure 3. Low ash carbon in the form of briquettes is delivered to the furnace through multiple inlets near the wall. (Although only two are shown in this cross-section, in reality the furnace would have many such inlets.) At least four, six or more, and more in large furnaces. This allows the carbon bed to form naturally during the routine operation of the furnace. It forms an inward facing cone shaped surface.

[0190] The nitrolox is introduced into the center of the reactor 40 (i.e., typically below the center of the conical surface of the carbon bed). The gas is added in a concentrated manner from above the furnace so that it falls as a single stream into the It collides with carbon, causing a highly exothermic reaction, as shown again here in reaction 15. . 2LiNO3+6C→2Li+6CO+N215)

[0191] On the other hand, lithium oxide present in nitrox can be reacted with nitroxylamine in the reaction 14, which is shown again here. ) and react according to Li2O+C→2Li+CO 14)

[0192] As mentioned above, the minimum reaction between lithium nitrate and lithium oxide occurs along with the energy supplied. The optimal balance of auxiliary energy provides optimal heat dissipation at temperatures above 1,500°C during operation. The reaction is carried out according to either reaction 14) or 15) so that the temperature is maintained. The purpose of this process is to ensure that the lithium metal remains in the gas phase.

[0193] In the embodiment shown in FIG. 3, reactions 14) and 15) occur in an area called the "combustion zone." This serves to remove solid carbon from the furnace 40 as carbon monoxide gas. Carbon is essentially continuously introduced from the vicinity to the center, and this carbon and nitrox blend react to give all gaseous or vaporous products (the right side of reactions 14 and 15) This means that the highest temperature in the reactor 40 is confined to its center, with the temperature increasing toward the walls. This reduces the stress on the individual components of the reactor 40. This reduces the heat loss from the reactor.

[0194] The carbon is also added to the reactor in a manner that ensures that the combustion zone remains well above the bottom of the reactor. The nitrolox blend is fed at a rate of 1000 rpm at suitable operating temperatures and pressures in reactor 40. The hot gas and steam are fed through a convergent-divergent (Laval) nozzle 42 at a rate that maintains the force. As mentioned above, the composition of the nitrolox blend is The reaction may be fine-tuned in the storage vessel 41 so that these criteria are met. The overall temperature level can be adjusted to the required level by electrical heating, such as an induction coil 43, incorporated in the vessel 40. Maintain high temperature.

[0195] FIG. 4 shows a variation of the furnace 40, in which the furnace 40 is a refractory-lined pressure vessel. In addition, the nitrolox blend has a blend unit 45 in the form of 40'. As part of the process control procedure, the nitrolox supply to vessel 40' ( The right-hand stream) can be blended with additional lithium nitrate (left-hand stream). Also shown in Figure 4 is a molten slag tap 47. The vessel 40' is otherwise similar to that described herein. It is similar to the furnace 40 described above and operates in a similar manner.

[0196] As with the gunpowder reaction, reaction 15) can be sustained if there is a sufficient supply of lithium nitrate. If the flow of lithium nitrate is interrupted, the reaction stops. The reaction resumes when the supply of lithium nitrate is resumed. The ratio of lithium nitrate in the input nitrolox blend was used as a process control variable. It can be used.

[0197] The logic behind US Patent No. 9,090,954 is that the induction coil (i.e., the nozzle in Figure 3) As shown by coil 43 of coil 42, a coil of the coil 43 is incorporated into the Laval nozzle 42 (i.e. , surrounding the throat), the throat during operation condenses refractory solids on its surfaces. The report requires that the temperature should be kept sufficient to prevent The process disclosed herein produces pure lithium nitrate (and thus pure nitrate). By using a very low ash carbon, the furnace 4 Therefore, during normal operation, the There should be no need to energize the coil 43 in the nozzle 42.

[0198] The off-gas and steam (right side of reactions 14 and 15) rise from the combustion zone and of trace elements, lithium oxide, and other refractory oxides that may enter the system in the feed stream. The presence of fine carbon particles dispersed in the off-gas can lead to the formation of trace elements in the furnace. ensures that the conditions in the In order to prevent such a reverse reaction, reactions 14) and 15) are The gas and steam produced at the right side of the furnace 40 is flash cooled. This is accomplished by having the only exit be via the Laval nozzle 42. The flow through the throat is sonic, but the gas and steam expand to supersonic speeds in the diverging section of the nozzle. and accelerates, this acceleration reduces the temperature from 2,000°C to 300°C within milliseconds. At this temperature, the conditions for reactions 14) and 15) to proceed in the reverse direction are not even present. Since it no longer exists, the lithium vapor quickly condenses into tiny droplets of liquid lithium metal. become.

[0199] In the embodiment of FIG. 3, this supersonic flow of gas and vapor is delivered to cyclone bank 44. The lithium droplets are removed from the gas stream and discharged to the underflow outlet (spigot). ) exits the cyclone bank 44. The liquid lithium is discharged from the spigot. The liquid flows into a storage tank 45, which is kept at a temperature such that its contents remain liquid. (i.e., a temperature above 180°C, preferably above 200°C). Molten lithium contains small amounts of refractory solids such as carbon, lithium oxide, and possibly other minerals. Stored lithium metal can be easily purified by vacuum distillation. It is possible to do this, although a suitable apparatus for doing so is not shown in FIG.

[0200] A liquid ring vacuum pump 46 creates a vacuum throughout the system downstream of the Laval nozzle 42. The liquid used in the liquid ring vacuum pump 46 is typically The liquid ring reduces the pressure in the Laval nozzle 42 by at least a factor of five. It not only creates a vacuum sufficient to allow the flow of carbon monoxide (and some nitrogen) gases, It also serves to scrub residual lithium values ​​from the fuel. It is used as a fuel, and the energy supplied from natural gas is used in the process of calcining the raw spodumene. Lithium nitrate is used in the smelting of spodumene ores (e.g., in the South American salt mines). If the gas does not originate from a natural resource (such as oil or gas oil), other uses for the gas fuel may be for electricity generation, etc. stomach.

[0201] <Further variations> Please note that there is a wide variation within the range of natural lithium sources described in this specification. In order to properly take these unique characteristics into account, practical techniques must be developed. In addition, measures will be taken to improve the provision of services and utilities, the efficient use of waste heat, In line with good engineering practices such as water conservation and minimization of all waste streams Thus, the overall process can include other unit operations.

[0202] In the following claims and the preceding description, neither expressly stated nor necessarily impliedly understood Unless the context otherwise requires, the words "comprises" and Variations of "comprises" and "comprising" is used in a generic sense, i.e. to identify the presence of the described feature. and does not exclude the presence or addition of further features.

Claims

1. A process for producing lithium oxide from lithium nitrate, comprising: a fraction of the lithium nitrate forms lithium oxide, and the remaining fraction of the lithium nitrate forms lithium oxide. The process includes pyrolyzing the cations so that they do not decompose into thium.

2. The pyrolysis is terminated after a set time, and the remaining fraction of the lithium nitrate is retained and the acid is 2. The process of claim 1, wherein the process produces a lithium nitrate product containing lithium chloride.

3. The termination involves cooling the partially decomposed product to below its decomposition temperature of about 600° C. The process of claim 2, comprising:

4. The product is further cooled to a temperature below about 260° C. to produce a solid lithium oxide-containing lithium nitrate.

4. The process of claim 3, which produces an aluminum product.

5. Producing the solid product in the form of prills, pellets, flakes, or the like; 5. The process of claim 4.

6. The lithium oxide-containing lithium nitrate product is dissolved in molten nitric acid having the lithium oxide dispersed therein. and heating to form lithium, and then adding one or more transition metal oxides, hydroxides, etc.

6. The method according to claim 1, wherein a carbonate or a nitrate is added together with any other electrode material. The process described.

7. The fraction of lithium nitrate that is thermally decomposed to lithium oxide is The process according to any one of claims 1 to 6, wherein the content of the cellulose in the cellulose membrane is about 50 to 90%.

8. Prior to pyrolysis, the lithium nitrate is subjected to a further pre-heating step to form a molten lithium nitrate salt. and then sending the molten lithium nitrate to a thermal decomposition stage and subjecting it to thermal decomposition.

8. The process according to any one of items 1 to 7.

9. The pyrolysis produces oxygen and nitrogen oxides, which are then recovered and used to produce nitric acid. The process of any one of claims 1 to 8, wherein the first floor is a floor on which the second floor is placed.

10. The nitric acid produced in the nitric acid production step is mixed with a lithium-containing silicate mineral. The mixture is then mixed with a nitrate solution to remove lithium values ​​from the silicate mineral. the silicate mineral is subjected to a leaching step in which the lithium nitrate is separated, and then 10. The method of claim 9, wherein the pyrolysis is carried out at 400° C. to form a lithium oxide-containing lithium nitrate product. The process of installation.

11. The lithium nitrate solution produced in the leaching step is concentrated and crystallized to obtain relatively pure crystals. Sexual LiNO ３ The process of claim 10 further comprising a crystallization step.

12. The crystallized LiNO ３ is separated from the solution by centrifugation or the like, and then the separated Crystalline LiNO ３ to form the lithium oxide-containing lithium nitrate product. The process of claim 11 .

13. The thermal decomposition may be performed by heating the lithium nitrate at atmospheric pressure or higher. The gaseous stream from the pyrolysis may be optionally heated with a nitrate or nitrate.

13. The process of any one of claims 1 to 12, wherein the acid is recovered for production.

14. The lithium oxide-containing lithium nitrate product of the thermal decomposition is converted to lithium gold by a reduction process or the like. The process according to any one of claims 1 to 13, wherein the genus

15. The reduction process comprises reacting the lithium oxide-containing lithium nitrate product with a carbon source. A temperature sufficient to thermally decompose the remaining lithium nitrate and reduce the lithium oxide to form a carbon source.

15. The process of claim 14, comprising heating to a temperature sufficient to oxidize said

16. Immediately after reduction to lithium, the lithium vapor and gaseous carbon dioxide are mixed with the liquid lithium 16. The process of claim 15, further comprising rapidly cooling to form a gypsum metal.

17. The lithium metal vapor and the gaseous carbon dioxide are subjected to a supersonic expansion through a converging-diverging nozzle.

17. The process of claim 16, wherein the rapid cooling is achieved by expansion of the mixture.

18. The liquid lithium metal and gaseous carbon dioxide are separated from each other, such as by passing them through a cyclone separation stage. and optionally recovering the gaseous carbon oxides for reuse as fuel.

7. The process according to claim 7.

19. Any of claims 1 to 18, wherein the source of lithium nitrate for the pyrolysis process comprises a salt plain. The process described above.

20. The lithium nitrate from the salt flat is converted into lithium-rich brine (LiC 1) was collected and Chilean saltpeter (NaNO ３ ) and then the resulting mixture is added. is subjected to a heat treatment step, such as evaporation, to produce a solution of lithium nitrate, process.

21. The heat treatment of the lithium-rich brine and nitrate mixture results in the formation of a mixture of normal salt (NaCl) from the solution, thereby producing a lithium nitrate solution.

21. The process of claim 20.

22. A reduction process for producing lithium metal from lithium nitrate, comprising: and heating the lithium nitrate together with a carbon source to a temperature sufficient to initiate a reaction between the lithium nitrate and the carbon. thereby reducing the lithium to lithium metal and oxidizing the carbon source to a gaseous state. The process.

23. The lithium nitrate to be heated is obtained from pyrolysis according to any one of claims 1 to 20. and the process is optionally 23. The process of claim 22, comprising adding additional lithium nitrate to the mixture.

24. Immediately after reduction, the lithium metal and gaseous carbon dioxide are mixed with the liquid lithium metal.

24. The process of claim 22 or 23, wherein the mixture is rapidly cooled to form a

25. The lithium metal vapor and the gaseous carbon dioxide are subjected to a supersonic expansion through a converging-diverging nozzle.

25. The process of claim 24, wherein the rapid cooling is achieved by expansion of the mixture.

26. The liquid lithium metal and the gaseous carbon dioxide are then passed through a cyclone separation stage or the like to separate the liquid lithium metal and the gaseous carbon dioxide. 24 or 25, wherein the gaseous carbon oxides are optionally recovered and reused as fuel.

25. The process according to claim 25.

27. A system for producing lithium oxide from lithium nitrate, comprising: to form lithium oxide, and The system includes a pyrolysis reactor configured so that the remaining fraction of the lithium oxide does not decompose into lithium oxide. Tem.

28. The pyrolysis reactor comprises a tank reactor, optionally a pressure vessel, and the tank reactor Molten lithium nitrate can be added to the top of the stirred tank reactor and the lithium oxide can be added to the The tank reactor is arranged so that a slurry of lithium nitrate containing the lithium nitrate can be withdrawn from the bottom of the tank reactor. The tank reactor provides a gas space above the slurry, and the gas space is filled with the Arranged to collect and extract nitrogen oxides and oxygen resulting from the decomposition of lithium nitrate. The system of claim 27.

29. The tank reactor is heated, optionally by an induction heating coil, to a temperature in excess of 600°C. and if in the form of a pressure vessel, it may be subjected to pressures above ambient, for example up to about 9 bar gauge. whereby the product of the tank reactor is oxidized 30. The system of claim 28 comprising a lithium nitrate liquid containing solid crystals of lithium.

30. prior to being transferred to said pyrolysis reactor to form a lithium oxide-containing lithium nitrate product. The lithium nitrate is heated to above its melting point temperature of about 260° C., optionally up to about 400° C. The system of any one of claims 27 to 29, further comprising an optional stirred and preheated vessel.

31. The method further comprises a nitric acid production reactor, such as an absorption tower, and the removed nitrogen oxides and oxygen are added to the nitric acid production reactor. and if the pyrolysis reactor is a pressure vessel, the system 28. The method of claim 27, wherein the gas is arranged to flow under pressure to the nitric acid production reactor. A system described in any one of claims 1 to 30.

32. The method further includes a leaching reactor, such as a pressure vessel, in which the nitric acid produced in the nitric acid production reactor is leached. The nitric acid is mixed with a lithium-containing silicate mineral, and the lithium value in the silicate mineral is dissolved in the nitric acid. The lithium nitrate is leached from the silicate mineral as lithium nitrate, and the lithium nitrate is filtered, etc. and then fed to a pyrolysis reactor to form lithium oxide. The system described.

33. A method for producing a lithium nitrate solution comprising: receiving the lithium nitrate solution produced in the leaching step, concentrating the solution and then crystallizing the solution; Relatively pure crystalline LiNO ３ The crystallizer further comprises a crystallizer configured to form 33. The system of claim 32.

34. Crystallized LiNO ３ is separated from the solution and then separated to form lithium oxide. Crystalline LiNO ３ to the pyrolysis reactor.

3. The system described in claim 3.

35. The method further includes a combustor, such as a pressurized catalytic combustor, in which the ammonia is mixed with an excess of air. and recovering and passing a gaseous product stream from said combustor to a nitric acid production reactor. A system according to any one of claims 27 to 34.

36. From the pyrolysis reactor, lithium nitrate liquid containing solid crystals of lithium oxide is The slurry is mixed with a carbon source, such as ash-free carbon briquettes, and the mixture is added to the slurry. Heating the lithium nitrate with carbon to convert it to lithium metal The system of any one of claims 27 to 35, further comprising a reduction furnace.

37. The method further includes a flash cooling device, such as a convergent-divergent nozzle, The resulting gaseous lithium metal is passed through the converging-diverging nozzle and expanded at supersonic speeds.

37. The system of claim 36, wherein the molten lithium metal is rapidly cooled, such as by heating the molten lithium metal. 。

38. The method further comprises a separation device, such as one or more cyclones, in which the molten lithium 38. The method of claim 37, wherein the metal is separated from gas produced in the reduction furnace during conversion to lithium metal. The system is as follows:

39. A reduction furnace for producing lithium metal, the furnace comprising a lithium oxide-containing lithium nitrate and a carbon source is disposed to receive the resulting mixture, the carbon source being capable of reacting with the ammonium salt in the product. The lithium nitrate is reacted with carbon so that the lithium is reduced to lithium metal. The carbon is supplied to the periphery of the reduction furnace, and the lithium oxide-containing lithium nitrate is heated to a temperature of 1000.degree. The aluminum product is supplied to the reduction furnace in a concentrated manner.

40. 1. A process for manufacturing a battery electrode, comprising: Nitric acid containing lithium oxide is added to form molten lithium metal containing dispersed lithium oxide. heating the lithium product; and One or more transition metal oxides, hydroxides, carbonates or nitrates may be combined with any of the electrode materials. Adding together, The process includes:

41. The lithium oxide-containing lithium nitrate product is produced by the process according to any one of claims 1 to 5, 7 to 13 or 19 to 21.

41. The process of claim 40, produced according to any of the processes described herein.

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