Patent Application
20240247337
The present invention relates generally to a process for co-producing lithium, aluminum, and silicon-oxygen (Si—O) materials, and more particularly, to a process for co-producing lithium, aluminum, and Si—O materials from a granular concentrate formed of one or more lithium-containing silicate minerals including spodumene.
None.
The invention described in U.S. Provisional Application 63/413,029 (filed on Sep. 30, 2022) was disclosed to Medaro Mining Corporation after Sep. 30, 2022 under the terms of a non-disclosure agreement in conjunction with a joint venture agreement.
Lithium (Li), aluminum (Al) and silicon (Si) materials, when recovered from sources in the Earth's crust and processed, are vital in numerous commercial applications. In the case of lithium and its compounds, the most common uses are in manufacturing lithium-ion batteries, lubricants, and glass ceramics, and in forming Li alloys with Al and magnesium (Mg). Aluminum and its compounds also have many different uses, such as, in the case of aluminum oxide, alumina (Al2O3): as a source of Al for manufacturing metallic Al, Al alloys, and glass ceramics; as an abrasive; and as a catalyst support. As for silicon, its common oxide, silica or silicon dioxide (SiO2), is used to make, for example, glass ceramics, silica-based glass optical fibers, fiberglass, precipitated silica, and silica gel.
Specifically with respect to lithium materials, the ever-increasing need for higher capacity and more long-lasting lithium batteries has fueled demand for lithium carbonate (Li2CO3), and lithium hydroxide monohydrate (LiOH·H2O). In response to this development, brine deposits in South America (mostly in Chile and Argentina) have become major sources of Li materials, especially Li2CO3. Concurrently, Li extraction from Li-containing silicate minerals has increased sharply, most notably from the mineral spodumene (in its purest form, LiAlSi2O6).
Regarding extraction of Li from spodumene, representative documents reflective of the state of the art include, e.g., US 2017/0175228 A1 (Hunwick) published Jun. 22, 2017, which describes a process comprising a thermal treatment unit configured to operate at a temperature that converts previously leached lithium material to solid lithium oxide (Li2O). The thermal treatment unit may comprise a roaster. The thermal treatment may also employ indirect heating of the extracted lithium material, which may be lithium nitrate (LiNO3). In the case of the lithium material being LiNO3, indirect heating may comprise the catalyzed burning of ammonia (NH3) in an excess of air. A stream of gas produced by thermal treatment may be collected for reuse in the acid leach and/or for regenerating nitric acid. The reference states that in the acid leach, the silicate mineral may be mixed with nitric acid. The reference also states that the leach conditions may comprise increased temperature and/or pressure to accelerate extraction of lithium values from the silicate mineral as lithium nitrates, but with non-lithium values in the silicate mineral tending not to be leached from the silicate mineral. As will become apparent from the text below, conditions tending to prevent leaching of non-lithium values are contrary to what occurs in the present invention.
Another reference, namely CA 3 009 374 A1 (Hunwick), published Jun. 29, 2017, discloses a process for recovering lithium from a silicate mineral, the process comprising: (a) mixing the silicate mineral with nitric acid; (b) subjecting a mixture obtained from step (a) to a leaching process having conditions such that lithium values in the silicate mineral are leached into an aqueous phase as LiNO3; (c) separating the LiNO3 from the aqueous phase; (d) subjecting the separated LiNO3 obtained from step (c) to a thermal treatment at a temperature that causes decomposition of the LiNO3 into solid lithium oxide, and such that a gas stream that comprises oxides of nitrogen is produced; and (e) passing the gas stream comprising oxides of nitrogen to a nitric acid production stage in which nitric acid is formed for reuse in the leaching process.
Furthermore, CN106906359A (ICSIP Pty Ltd.), published Jun. 30, 2017, discloses a process for recovering lithium from silicate minerals in which, in an embodiment described as a sidestream treatment regime, lithium may be precipitated as lithium carbonate using ammonium carbonate.
Additionally, CN113603122A (Hunan Tiantai Tianrun New Energy Technology Co. Ltd.), published Nov. 5, 2021, discloses a method for synthesizing battery-grade lithium carbonate, which specifically includes the following steps: S1: Pretreatment: after discharging, disassembling, and crushing the recycled waste lithium iron phosphate battery, electrode powder is obtained; S2: Nitration reaction: the above electrode powder is added to the nitric acid solution for nitration reaction, the liquid-solid ratio is 4:1, and the nitrate product is obtained after the reaction; S3: roasting: roasting the above nitrate product to obtain calcine; S4: Leaching: leaching the calcine with water, with a solid-liquid ratio of 1:2, and filtering to obtain a lithium-rich solution; S5: Preparation of battery-grade lithium carbonate: adding carbonate (e.g., ammonium carbonate) to a lithium-rich solution at 50° C. while stirring. The reference states that after reacting, filtering and washing, drying, sieving, and packaging, battery-grade lithium carbonate is obtained.
CN115537580A (Jiangxi Shanning Technology Co. Ltd.), published Dec. 30, 2022 (which is after the priority date of the present application), discloses a method for extracting lithium in lithium ore, comprising the steps of: 1) after mixing lithium ore with saltpeter, ball milling, roasting, acid leaching, and filtering, lithium-containing solution and silicon-rich slag are obtained; 2) precipitating lithium after mixing the lithium-containing solution and carbonate (e.g., ammonium carbonate) to obtain a lithium-containing compound; wherein, the lithium ore is selected from “at least two kinds of spodumene, lepidolite, and lithium china stone.” In a preferred embodiment, the precipitation is described as being conducted at 85-100° C.
Furthermore, CN1024124C (Xinjiang Non-Ferrous Metal Inst.), published Apr. 6, 1994 discloses a method for making quilonum retard involving, among other steps, using a ammonium carbonate precipitating agent to obtain lithium carbonate from a sulfate solution containing lithium.
In view of the foregoing state of the art, there remains a need in the art for a more technically robust, and a more environmentally benign process to recover lithium values from lithium-containing silicate minerals that include spodumene.
There also remains a need in the art to develop a process that can lower current overall beta (β) spodumene conversion costs by about 30-50%, β-spodumene being a crystallographic form of spodumene that is susceptible to leaching by various types of solvents.
There also remains a need in the art for a β-spodumene conversion process that allows for the recovery of not only lithium values but also aluminum and silicon values.
There also remains a need in the art for a β-spodumene conversion method whereby valuable Li-, Al-, and Si—O-containing materials are co-produced and subsequently separated to substantially complete extents approaching 100% by reactions that occur at temperatures less than or equal to (5) about 600° C.
There also remains a need in the art for a β-spodumene conversion method in which Li-, Al-, and Si—O-containing materials are produced, separated, and recovered in closed-loop internal chemical cycles, which are designed to avoid or substantially reduce incorporation of any Li, Al, and/or Si into any kind of solid, liquid, or gaseous waste material.
There also remains a need in the art for a β-spodumene conversion method whereby the only waste materials produced are essentially: first, the quartz, feldspar, and other lithium-poor silicate minerals that commonly occur in a spodumene concentrate; and second, the very small (i.e., inconsequential, negligible, or trace) amounts-typically less than about 2% by weight—of crystallographically bound iron, manganese, sodium, potassium, magnesium, calcium, etc. that are inevitably released when β-spodumene is converted to Li-, Al-, and Si—O-containing materials as the steps according to the present invention are carried out.
There also remains a need in the art for a physicochemical process that not only can co-produce valuable Li, Al, and Si—O materials, but also can be implemented in compact, modular, and highly scalable manufacturing facilities that are amenable to deployment in remote geographic locations.
One or more of the foregoing needs, as well as other needs, may be fulfilled by the invention described below.
The present invention discloses a process for co-producing Li, Al, and Si—O materials from a hard rock source, spodumene, which is converted to its beta (β) crystallographic form. In particular, the process according to the present invention is a new and radically different thermochemical technology that extracts Li from β-spodumene and converts it to Li2CO3 and/or LiOH·H2O. In addition, the process allows for co-production of commercially saleable Al and Si—O materials such as aluminum hydroxide (Al(OH)3), aluminum oxide (Al2O3), and various forms of SiO2. In one embodiment, after nitric acid extraction of extensive amounts of Li and Al from the β-spodumene in a calcined spodumene concentrate, the process employs a thermal (heat) treatment of the combined liquid fractions obtained, first, from nitric acid leaching, and second, from water washing of the leached granular β-spodumene fraction, the purpose being to produce, separate, and recover an aluminous precipitate. Optionally, an aluminous precipitate may alternatively or additionally be formed by contacting the combined liquid fractions with one or more of: an aqueous solution of ammonium hydroxide (NH4OH); an aqueous solution of ammonium carbonate ((NH4)2CO3); and solid (NH4)2CO3. Subsequently: (i) a physical means of solid-liquid separation is used to recover the aluminous precipitate; (ii) the liquid obtained from solid-liquid separation is contacted with a source of ammonia-carbon dioxide (NH3—CO2) gas and/or (NH4)2CO3 to produce a solid Li2CO3 precipitate; (iii) a physical means of solid-liquid separation is used to recover the Li2CO3 precipitate; and (iv) processing steps are taken to regenerate and reuse chemicals that enable additional production, separation, and recovery of Li, Al, and Si—O materials, those recycled chemicals themselves containing less than about 5 weight % (wt. %) dissolved, suspended, or entrained Li, Al, and Si—O materials.
In one embodiment, the present invention is directed to a process for extracting Li, Al, and Si—O materials from a hard rock source in the form of a granular concentrate of one or more lithium-containing aluminosilicate minerals including spodumene comprising:
The phrase “water of sufficient purity” in the context of the present invention is intended to refer to any water having a sufficient purity for use in a process according to the present invention and may include untreated meteoric water or groundwater, or water that has been purified according to known ways, such as filtration, distillation (including in situ condensation within the processing system), and/or treatment by reverse osmosis (RO)/deionization (DI) to a purity level typically required for process water in the extraction or production of Li suitable for commercial use, such as in batteries. One skilled in the art would understand, or would be able to determine by routine experimentation, what level(s) of purity is/are required.
In a further embodiment, all or substantially all of the chemicals (e.g., HNO3) and water of sufficient purity are recycled to achieve significant cost savings.
In another embodiment of the invention, co-production of Li, Al, and Si—O materials from the β-spodumene in a calcined spodumene concentrate comprises the following steps (Note:
Additional specifics of the steps in the embodiment are presented in the detailed description below.
Illustrated by way of the attached figures, the present invention is directed toward a process for co-producing Li-, Al-, and Si—O-containing materials from the β crystallographic form of spodumene, which in its purest state has the composition LiAlSi2O6. The description below presents an exemplary non-limiting embodiment of the invention, while the appended claims define the scope of patent protection.
Throughout the text that follows, the words “transferred,” “conveyed,” “separated,” and “impurities” may be understood to mean the following.
In the case of the words “transferred” and “conveyed,” when used to indicate movement in the physical location of a liquid or slurry, the understanding can be that the material may be pumped mechanically or gravitationally, or by differential pressure.
In the case of the word “separated,” when used in reference to dividing a slurry into solid and liquid portions, the understanding can be that the segregation may be accomplished by centrifugation and/or filtration.
In the case of the word “impurities,” usage is inclusive of both mineralogical and chemical contaminants in the materials that enter into, move through, and ultimately exit, the processing circuit. Mineralogical impurities include quartz, feldspar, and other substantially lithium-free crystalline solids that can occur in a spodumene concentrate. Significantly, a spodumene concentrate may also contain subordinate amounts of lithium-containing minerals that differ from spodumene—e.g., petalite, lepidolite and amblygonite—and it should be understood that the processing steps of the present invention are likely to have effects on them that are similar to the effects they have on spodumene. Nevertheless, herein, no further attention is given to any accessory granite pegmatite minerals that might be present in a spodumene concentrate.
Regarding chemical impurities, the only ones considered below are selected minor and trace elements that commonly occur crystallographically in spodumene-namely, iron, manganese, sodium, potassium, magnesium and calcium. It will be proposed that problems associated with these contaminants can be handled post-dissolution (in aqueous media) by: (i) using a caustic aqueous liquid (e.g., aqueous ammonium hydroxide, NH4OH) to induce precipitation of calcium hydroxide, magnesium hydroxide, and Fe—Mn oxides and hydroxides; or (ii) using a bicarbonate/carbonate material (e.g., aqueous ammonium carbonate, (NH4)2CO3, or solid (NH4)2CO3) to induce precipitation of calcium carbonate and magnesium carbonate prior to converting LiNO3 to Li2CO3; and (iii) allowing solubilized alkali metals (most notably Na and K) to remain in solution until after all valuable Li, Al and Si—O materials are formed and separated.
Another important point: to simplify discussions of certain key processing steps, and also the representations of those steps on
It should also be understood that, in the various presented chemical reactions, the abbreviations enclosed in parentheses—appended to the formulas for the chemical species—have the following definitions: s=solid, liq=liquid, aq=in aqueous solution, and g=gas.
It is envisioned that, generally, the reactors referred to below may be continuous stirred-tank reactors that are very compact due to the rapid kinetics of the reactions that occur within them.
It is also envisioned that each cooling unit referred to below could be a heat exchanger, or could simply be a tube enveloped by a heat transfer fluid, thermostated or not.
It is also envisioned that satisfactory blending of liquids and gases in the invented process can, in many instances, be achieved in a static mixer.
Finally, after weighing the merits of the chemical technology disclosed in this Specification, it will be evident to those skilled in the art that the method can be applied at length scales ranging from the laboratory benchtop to the factory floor.
Now, referring to
Step 1: A granular spodumene concentrate, with the spodumene in it being predominantly in its α crystallographic form, is provided.
Spodumene is a natural mineral with the ideal/pure/theoretical/end-member composition LiAlSi2O6. A spodumene concentrate is a granular mechanical mix of minerals formed by crushing and grinding rock excavated from a spodumene pegmatite formation, with the proportion of spodumene in the resulting granular solids typically being enhanced by at least one concentration method, such as dense medium separation and froth flotation.
Other lithium minerals, such as petalite (ideally LiAlSi4O10), lepidolite (ideally K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2), and amblygonite (ideally (Li,Na)AlPO4(F,OH)), may also be present in a spodumene concentrate, but always in subordinate amounts. Significantly, three other subordinate minerals commonly present in a spodumene concentrate—quartz (ideally SiO2), albite (ideally NaAlSi3O8), and microcline/orthoclase (ideally KAlSi3O8)—contain only negligible amounts of lithium, and for this reason are hereafter referred to as “mineral impurities” to distinguish them from chemical impurities.
Supplies of spodumene concentrate sold commercially are usually graded according to their Li2O content. Pure spodumene contains 8.03 weight percent (wt. %) Li2O; a run-of-mine spodumene pegmatite ore ordinarily contains 1-2 wt. % Li2O; a spodumene concentrate—the proportion of spodumene in it commonly being between 75 and 87% by weight—a desirable attribute for use in Li compound manufacturing—will typically contain 6-7 wt. % Li2O. Spodumene concentrates containing at least 7.6 wt. % Li2O, and having a low iron content, are consumed in making ceramics, and in other specialty applications.
Step 2: The granular α-spodumene concentrate provided in Step 1 is calcined at an elevated temperature, or over a range of temperatures, e.g., between about 900° C. and about 1,200° C., but more usually at a temperature, or over a range of temperatures, between about 950° C. and about 1100° C., the main purpose being to convert all α-spodumene to β-spodumene.
Step 3: An aqueous solution of HNO3 and/or a N—O—H gas+H2O is/are provided and mixed into the granular β-spodumene concentrate immediately prior to, or shortly after, entry into a first reactor (Reactor #1 on
If provided, the HNO3-containing aqueous solution could contain between about 20 wt. % and about 68 wt. % HNO3, the balance being mostly water. Most preferably for commercial applications, the aqueous solution would contain between about 40 wt. % and about 68 wt. % HNO3.
Both the aqueous HNO3 (if provided) and the N—O—H gas (if provided) could be preconditioned to about 25≤T(° C.)≤about 140, and to about 1≤P(atm)≤about 10, prior to being conveyed to the reactor. In any case, the final temperature of the resulting acidic slurry would advantageously be about 120≤T(° C.)≤about 140° C. Heating to a temperature as high as about 140° C. could be accomplished by flowing the multiphase material through one or more pipes immersed in a heat transfer liquid. As flow of the material occurs, the pressure and temperature of the entire amount of it could be maintained, or allowed to increase slightly.
During this step, leaching of the granular β-spodumene commences, with at least a significant amount of the Li in the mineral, along with a lesser portion of the Al in it, becoming dissolved in the acidic aqueous liquid (see below). This is in direct contrast to the prior art reference's (US 2017/0175228 A1 (Hunwick)) description discussed above, in which the leaching conditions created are such that non-lithium values tend not to be leached from the silicate mineral. Indeed, one of the key features of the process according to the present invention is extraction of both Li and Al during nitric acid leaching of granular β-spodumene.
Data obtained from bench-scale laboratory testing indicates that β-spodumene contact with aqueous HNO3 at about 120° C. and 1 atm results in extensive leaching of Li, lesser (but still significant) leaching of Al, and negligible leaching of Si—O materials. Therefore, rather than dividing β-spodumene into discrete Li, Al, and Si—O portions, which is the ultimate goal of the invented process, the currently available evidence, instead, indicates that the contact yields a partially leached solid material which: possibly contains a small amount of residual Li; likely contains a substantial amount of residual Al; and certainly contains most of the Si—O material that was originally present in the β-spodumene. Consequently, it is contemplated that final compositions for nitric acid-leached β-spodumene may include LiAl3Si8O20(OH)2, LiAl4Si32O70OH and/or Al4Si64O134-solid aluminosilicates with these compositions conceivably being formed by one or more reactions similar to Reaction 1 below, as well as the other two that immediately follow it:
It will be understood that the calculated numbers above the species in Reaction 1, and in certain related reactions that follow in this disclosure, are tonne mass balance figures for the production of 1 tonne of LiOH·H2O, assuming that (i) the LiOH·H2O is produced according to Reaction 4 below and (ii) the ultimate source of the Li in the LiOH·H2O is the LiAlSi2O6 in the β-spodumene that reacts with aqueous HNO3 according to Reaction 1.
A guiding principle in achieving satisfactory nitric acid Li—Al leaching of β-spodumene is that solid-liquid mixing would best be accomplished under physicochemical conditions that tend to sustain, or even increase, the wt. % concentration of aqueous HNO3, while at the same time precluding any significant loss of β-spodumene. For example, to mitigate against the decrease in wt. % aqueous HNO3 that occurs during leaching of Li and Al from β-spodumene: (i) the starting wt. % concentration of aqueous HNO3 might be higher than absolutely necessary, e.g., in the range 50-68 wt. %; and/or (ii) the initial aqueous HNO3 to β-spodumene weight ratio might be set high enough, to ensure that the wt. % concentration of aqueous HNO3 remains high throughout the period of Li—Al leaching. Additionally, or alternatively, the wt. % aqueous HNO3 might be kept high by N—O—H gas, the sustained presence of which would induce the reaction
the result being that depletion of aqueous HNO3 by reaction with β-spodumene would be counteracted by replenishment of aqueous HNO3 due to reaction between NO2, O2 and H2O.
Finally, at the conclusion of this step, the acidic aqueous slurry in the reactor, which would preferably contain between about 30 volume percent and about 70 volume percent solids, is transferred to a second reactor (Reactor #2 on
Step 4: The ambient pressure in Reactor #2 is lowered to an extent necessary to convert most of the remaining aqueous HNO3 to N—O—H gas.
Gas pressure in Reactor #2 could be lowered to about 1 atm by creating a headspace wherein gas can enter from the heated aqueous slurry below, and from which gas can be extracted through the one or more sides of, and/or through the top of, the headspace, this facilitating degassing of the slurry. It is contemplated that the removed gas will contain N—O—H volatile species—e.g., HNO3, H2O, NO2, and O2.
Step 5: The aqueous HNO3-depleted slurry formed in Reactor #2 is conveyed to a cooling unit where its temperature is lowered to a level satisfactory for transfer to a separator.
Conveyance of the slurry might be driven, entirely or partially, by a gradient in fluid pressure.
Step 6: After cooling down to about 25≤T(° C.)≤about 60, the slurry is transferred to a separator where it is divided into two fractions, one fraction comprising substantially all of the leached granular β-spodumene (accompanied by subordinate amounts of one or more accessory lithium pegmatite minerals), the other fraction being a LiNO3- and Al(NO3)3-containing aqueous liquid that contains minimally detrimental amounts of residual dissolved, suspended and/or entrained solids, a portion of them being impurities.
After separation, the reacted granular solids are slurried with water of sufficient purity and conveyed to a mixer-washer connected to a separator. Also, optionally, the liquid produced by separation is filtered prior to transfer to a first liquid mixer (Liquid mixer #1 on
Step 7: The water-slurried granular solids sent to the mixer-washer are stirred and/or agitated prior to transfer to a separator, the LiNO3- and Al(NO3)3-containing wash water thus produced then being sent to Liquid mixer #1 where it coalesces with the LiNO3- and Al(NO3)3-containing aqueous liquid formed in Step 6.
Preferably, the solids would be washed in a minimum amount of water of sufficient purity, and after separation of the solids could optionally be reacted with aqueous/crystalline NaOH and/or aqueous/crystalline KOH to produce a caustic (Na and/or K,Li,Al,Si—O)—H2O liquid (Step 39).
Step 8: The LiNO3- and Al(NO3)3-containing aqueous liquid in Liquid mixer #1 is conveyed to a third reactor (Reactor #3 on
(Important note: Steps 9a-c below describe three potentially independent means for producing a H2O-containing aluminous precipitate from a LiNO3- and Al(NO3)3-containing aqueous liquid. For the sake of simplicity and brevity, hereafter this precipitate is designated “Al(OH)3,” with the understanding that, in reality, it is a water-rich substance that may contain abundant amorphous Al—O—H semi-solid (gelatinous) material, possibly intermixed one or more quasicrystalline Al—O—H phases.)
Step 9a: The LiNO3- and Al(NO3)3-containing aqueous liquid residing in Reactor #3 is heated to ≥about 140° C. to decompose substantially all of the dissolved Al(NO3)3, a key result being precipitation of Al(OH)3. (As noted previously, in this invention disclosure a thermal treatment is the chosen exemplary treatment option for converting aqueous Al(NO3)3 to Al(OH)3. Steps 9b and 9c below are described solely to point out that there are alternative methods for inducing precipitation of Al(OH)3 from a LiNO3- and Al(NO3)3-containing aqueous liquid.) It is contemplated that the aqueous Al(NO3)3 will be decomposed by a reaction similar to this one:
Step 9b: A liquid comprising NH4OH dissolved in water, and/or a gas containing a substantial amount of NH3, is provided and mixed with the liquid residing in the third reactor to precipitate Al(OH)3. It is contemplated that one or both of these actions will reduce the amount of Al(NO3)3 in the aqueous liquid by a reaction similar to this one:
In commercial settings, precipitation of Al(OH)3 by either action would preferably be accomplished at about 25≤T(° C.)≤about 60, and at about 1≤P(atm)≤about 10.
Step 9c: An aqueous liquid containing dissolved (NH4)2CO3, and/or a material containing granular (NH4)2CO3, and/or a gas containing substantial amounts of NH3 and CO2, is provided and mixed with the liquid residing in Reactor #3, the purpose being to precipitate Al(OH)3.
Three possible reactions that relate to the use of (NH4)2CO3 to induce the precipitation of Al(OH)3 from a LiNO3- and Al(NO3)3-containing aqueous liquid are
It is contemplated that, with any of the above reactions, precipitation of Al(OH)3 could be induced at about 25≤T(° C.)≤about 60, and at an ambient pressure of about 1 atm. To ensure optimal production of Al(OH)3 in commercial settings: first, the amount of provided (NH4)2CO3 should be close to the minimum amount required to react away nearly all of the aqueous Al(NO3)3 present in the liquid; and second, the produced CO2±O2 gas should be removed from the reactor as it forms.
Step 10: The Al(OH)3- and LiNO3-containing aqueous slurry formed in Step 9a is conveyed from Reactor #3 through a cooling unit into a mixer connected to a separator.
Step 11: The slurry in the mixer is stirred and/or agitated prior to flow into a separator where it is divided into two fractions, one fraction being substantially Al(OH)3, the other fraction a LiNO3-containing aqueous liquid.
After separation, the Al(OH)3 is slurried with water and conveyed to a mixer-washer connected to a separator. Also, optionally, the LiNO3-containing aqueous liquid produced by separation is filtered prior to transfer to a second liquid mixer (Liquid mixer #2 on
Step 12: The water-slurried Al(OH)3 sent to the mixer-washer is stirred and/or agitated prior to being divided into Al(OH)3-rich and wash water-rich fractions.
Preferably, after adding water to the Al(OH)3 in Step 11, the resulting slurry in the mixer-washer will contain about 30-70 volume percent solids. The newly formed slurry is then stirred and/or agitated, and thereafter the Al(OH)3 and wash water in it are separated, possibly by centrifugation and/or filtration. At the end of this step the wash water is sent to Liquid mixer #2 where it coalesces with the LiNO3-containing aqueous liquid formed in Step 11.
Step 13: The moist Al(OH)3 produced in Step 12 may be heated to a temperature, or over a range of temperature, between about 100° C. and about 300° C., to dehydrate the material, this possibly leading to the production of one or more forms of crystalline Al(OH)3 and/or crystalline Al2O3.
Step 14: Optionally, the Al—O—H solid(s) produced in Step 13 are processed further to produce one or more forms of high-quality Al2O3, and/or Al metal.
Step 15: The LiNO3-containing aqueous liquid in Liquid mixer #2 is transferred to a fourth reactor (Reactor #4 on
Step 16: The LiNO3—H2O liquid in Reactor #4 is merged with either: (i) a mixed NH3—CO2 gas having a composition previously shown to be suitable for converting aqueous LiNO3 to granular Li2CO3, the amount of NH3—CO2 gas provided being sufficient to react away nearly all of the aqueous LiNO3; or (ii) an (NH4)2CO3-containing aqueous liquid and/or granular (NH4)2CO3, the amount of aqueous/solid (NH4)2CO3 supplied being in excess of that required to react away substantially all of the aqueous LiNO3.
(Optionally, at the outset of this step, a small amount of NH3—CO2 gas and/or aqueous/solid (NH4)2CO3 is mixed into the LiNO3-containing aqueous liquid to induce precipitation of CaCO3- and MgCO3-containing solid material, the precipitate preferably being immediately separated from the enclosing liquid by filtration and/or centrifugation.)
In the case of merging the LiNO3—H2O liquid with a sufficient amount of NH3—CO2 gas of suitable composition, or range of compositions, it is contemplated that precipitation of granular Li2CO3 would occur mainly by the reaction
In the case of merging the LiNO3—H2O liquid with a sufficient amount of an (NH4)2CO3-containing aqueous liquid and/or with granular (NH4)2CO3—the amount of (NH4)2CO3 supplied being in excess of that required to react away substantially all of the aqueous LiNO3—it is contemplated that precipitation of granular Li2CO3 would occur principally by the reaction
In any case, in commercial settings this step would preferably be completed at about 25≤T(° C.)≤about 80, and at about 1≤P(atm)≤about 10—and at its conclusion the produced Li2CO3—, NH4NO3- and (NH4)2CO3-containing aqueous slurry would be transferred to a fifth reactor (Reactor #5 on
Step 17: The Li2CO3-, NH4NO3- and (NH4)2CO3-containing aqueous slurry transferred to Reactor #5 is heated to decompose substantially all of the aqueous (NH4)2CO3, this likely being the result of the reaction
which in commercial settings would preferably be induced at about 60≤T(° C.)≤about 120, and at a pressure close to 1 atm. To ensure maximum decomposition of the residual aqueous (NH4)2CO3, the produced NH3—CO2 gas should be removed from the reactor as it forms.
Step 18: The Li2CO3- and NH4NO3-containing aqueous slurry produced in Reactor #5 is sent through a cooling unit into a mixer connected to a separator.
Step 19: The slurry in the mixer is stirred and/or agitated prior to flow into a separator where it is divided into two fractions, one fraction being substantially granular Li2CO3, the other fraction a NH4NO3-containing aqueous liquid.
After separation, the Li2CO3 is slurried with, preferably, 30-70 volume percent water, and subsequently conveyed to a mixer-washer connected to a separator. Also, optionally, the NH4NO3-containing aqueous liquid produced by separation is filtered prior to transfer to a third liquid mixer (Liquid mixer #3 on
Step 20: The water-slurried granular Li2CO3 sent to the mixer-washer is stirred and/or agitated prior to being divided into Li2CO3-rich and wash water-rich fractions.
At the end of this step the wash water is sent to Liquid mixer #3 where it coalesces with the NH4NO3-containing aqueous liquid formed in Step 19.
Step 21: The moist Li2CO3 produced in Step 20 is optionally further processed to remove impurities—and then optionally heated to a temperature, or over a range of temperature, between about 80° C. and about 120° C. to thoroughly dry the material.
Step 22: Optionally, the moist Li2CO3 produced in Step 20, or the Li2CO3 optionally purified and/or dried in Step 21, is converted to LiOH(aq) and/or solid LiOH·xH2O (x=1, 2, 3, or 6).
Conversion of granular Li2CO3 to, for example, granular LiOH·H2O can be achieved in several ways, a particularly well-known one being by the metathesis reaction
followed by adjustment of the hydration state of the LiOH·xH2O to produce LiOH·H2O.
Step 23: After a sufficient residence time in Liquid mixer #3, the NH4NO3-containing aqueous liquid that exits from it is optionally heated to about 120° C. during flow toward a mixer (
Step 24: After it reaches the mixer, the NH4NO3-containing aqueous liquid is contacted with an excess amount of granular MgO.
Optionally, the MgO is heated prior to entering the mixer, and at the end of this step the produced MgO±Mg(OH)2- and NH4NO3-containing aqueous slurry is conveyed to a sixth reactor (Reactor #6 on
(In the text that follows it is assumed that, in Step 23, the NH4NO3-containing aqueous liquid sent to the mixer is heated prior to its arrival there, and in Step 24, the heated NH4NO3-containing aqueous liquid is contacted with heated MgO.)
Step 25: The slurry in Reactor #6 is stirred and/or agitated at about 120° C. for a sufficient period of time to react away substantially all of the aqueous NH4NO3.
It is contemplated that aqueous NH4NO3 will disappear from the slurry by all three of the reactions below:
Delivery of an excess amount of MgO to Reactor #6 is recommended for two reasons: first, the kinetics of Reaction 5a will slow down significantly if the amount of MgO present approaches zero; and second, some of the introduced MgO will combine with H2O to form Mg(OH)2 (Reaction 5b), Mg(OH)2 being less reactive with NH4NO3 than MgO because Mg(OH)2 is stable in the presence of hot liquid H2O whereas MgO is not.
At the end of this step the produced Mg(NO3)2- and Mg(OH)2±MgO-containing aqueous slurry is transferred to a mixer connected to a separator (see Step 28).
Step 26: The NH3—CO2 gas produced in Step 17, the NH3 gas that exits Reactor #6, and provided CO2 gas are combined in a gas mixer connected to a cooling unit.
To enhance processing effectiveness in the present invention, the composition of the NH3—CO2 gas should be made suitable for consumption in either Step 16, or in the next step.
Step 27: Optionally, the mixed NH3—CO2 gas exiting the cooling unit is transferred to a seventh reactor (Reactor #7 on
It is contemplated that aqueous (NH4)2CO3 will be formed by the reaction
at about 25≤T(° C.)≤about 80, and at about 1≤P(atm)≤about 10. Also, optionally (not shown on
At the conclusion of this step the (NH4)2CO3-containing aqueous liquid and/or granular (NH4)2CO3 is sent back to Step 16.
Step 28: The Mg(NO3)2- and Mg(OH)2±MgO-containing aqueous slurry in the mixer immediately downstream from Reactor #6 is stirred and/or agitated prior to flow into a separator where it is divided into two fractions, one fraction being substantially fine-grained Mg(OH)2±residual MgO, the other fraction being a Mg(NO3)2-containing aqueous liquid.
At the end of this step: (i) the moist Mg(OH)2±MgO is slurried with, preferably, about 30-70 volume percent water, and subsequently sent to a mixer-washer connected to a separator; and (ii) the Mg(NO3)2-containing aqueous liquid is conveyed to a fourth liquid mixer (Liquid mixer #4 on
Step 29: The aqueous Mg(OH)2±MgO slurry in the mixer-washer is stirred and/or agitated prior to being divided into Mg(OH)2±MgO-rich and wash water-rich fractions.
At the end of this step a portion of the moist Mg(OH)2±MgO is conveyed to a first furnace (Furnace #1, see Step 33 on
Step 30: The Mg(NO3)2-containing aqueous liquid in Liquid mixer #4 is sent to an evaporator.
Step 31: The Mg(NO3)2-containing aqueous liquid in the evaporator is heated to about 150° C., the result being production of molten Mg(NO3)2·xH2O and water vapor, and possibly also N—O—H gas.
The melting temperatures of Mg(NO3)2·6H2O and Mg(NO3)2·2H2O reported in the literature are 89° C. and 129° C., respectively. With increasing temperature above 129° C. the composition of a hydrous Mg(NO3)2 melt can be represented by the formula Mg(NO3)2·xH2O, with x being <2.0 and the value of x steadily decreasing to <<2.0 with increasing temperature. Thus, it is contemplated that, with increasing temperature above about 129° C. to about 330° C. (the latter being the approximate upper thermal stability limit of anhydrous Mg(NO3)2), molten Mg(NO3)2·H2O dehydrates by the reaction
where 0≤y<2.
At the conclusion of this step the produced N—O—H gas (if any) is transferred to a gas mixer (see Step 37 on
Step 32: In the mixer (
Step 33: The moist Mg(OH)2±MgO in Furnace #1 is heated to a temperature as high as about 600° C. at about 1-2 atm, the result being production of MgO and water vapor by the reaction
At the conclusion of this step the produced MgO is recycled back to Step 24.
Step 34: The Mg(NO3)2·xH2O+Mg(OH)2±MgO slurry in Furnace #2 is heated to a temperature as high as about 600° C. at about 1-2 atm, the result being production of MgO and a NO2-, O2- and H2O-containing N—O—H gas.
It is contemplated that the Mg(NO3)2·xH2O portion of the slurry would be decomposed by the reaction
At the conclusion of this step: (i) produced MgO is slurried with a liquid and conveyed to a mixer-washer connected to a separator; and (ii) the co-produced NO2- and O2-containing N—O—H gas is transferred to a gas mixer (see Step 37). Preferably, the slurry sent to the mixer-washer would contain about 30-70 volume percent liquid. Also, the liquid in the slurry should be one in which MgO is substantially insoluble but impurities (e.g., alkali nitrates) are significantly soluble.
Step 35: The slurry in the mixer-washer is stirred and/or agitated prior to being divided into MgO-rich and liquid-rich fractions.
Optionally, the MgO formed in this step is further purified prior to being recycled back to Step 24.
Step 36: Optionally, the liquid+impurities formed in Step 35 is treated physically and/or chemically in a way that divides it into two fractions, one fraction being a liquid that contains very little dissolved, suspended and/or entrained solid material, the other fraction comprising mainly impurities that were held in the liquid prior to the physical and/or chemical treatment.
Optionally, the high-purity liquid is recycled back to Step 35.
Step 37: The N—O—H gas removed from Reactor #2 and Reactor #3 (Steps 4 and 9a), the N—O—H gas produced in the evaporator (if any) (Step 31), and the NO2-, O2- and H2O-containing N—O—H gas formed in Furnace #2 (Step 34, and subsequently cooled), are received by a gas mixer and intermingled there.
Optionally, some H2O may purposely be condensed from the mixed gas and separated for reuse in the processing circuit, and also optionally (i) some or all of the mixed gas is sent back to Step 3 to replenish a significant portion of the aqueous HNO3 that is consumed during that step, and/or (ii) some or all of the mixed gas is conveyed to an eighth reactor (Reactor #8 on
Step 38: The N—O—H gas sent to Reactor #8 (if any) is mixed into H2O to produce aqueous HNO3, which is subsequently recycled back to Step 3 to replenish a significant portion of the aqueous HNO3 that is consumed during that step.
It is possible that mixing NO2- and O2-containing N—O—H gas with water—at one or more points in the processing circuit—will produce HNO3 in two stages, the first involving formation of a portion of HNO3 by the reaction
the second featuring further HNO3 synthesis by the reaction
In any event, the overall HNO3 regeneration reaction is expected to be
Step 39: Optionally the water-washed leached granular solids produced in Step 7 are transferred to a ninth reactor (Step 39) where they are mixed with aqueous/crystalline NaOH and/or aqueous/crystalline KOH to produce a (Na and/or K,Li,Al,Si—O)—H2O liquid.
Table 1 below shows the calculated tonnes of each species consumed (C) and produced (P) in each of Reactions 1, 2a, 3b, 4, 5a, 5b, 6, 7, 8, and 9, in a hypothetical example where all ten reactions proceed to completion in the production of one tonne of LiOH·H2O.
Table 2 below shows the calculated total amounts (tonnes) of the reactants and reaction products, mass balanced, for each of Reactions 1, 2a, 3b, 4, 5a., 5b, 6, 7, 8, and 9, in a hypothetical example where all ten reactions proceed to completion in the production of one tonne of LiOH·H2O.
This non-provisional application claims priority to U.S. Provisional Application 63/455,079 filed on Mar. 28, 2023 and also claims benefit of an earlier filing date as a continuation-in-part application of U.S. Non-Provisional application Ser. No. 18/375,341 filed on Sep. 29, 2023, which claims priority to U.S. Provisional Application 63/412,029, filed on Sep. 30, 2022. U.S. Provisional Applications 63/455,079 and 63/412,029 and U.S. Non-Provisional application Ser. No. 18/375,341 are all incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63455079 | Mar 2023 | US | |
| 63412029 | Sep 2022 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 18375341 | Sep 2023 | US |
| Child | 18617548 | US |
