Inhibitor for alkali and alkaline earth metals

Abstract

The described technology relates to a safe dissolution process for alkali metals, alkaline earth metals, and alloys containing at least one of these metals. The process involves contacting the metal with an inhibitor and water. In this process, the inhibitor is selected from hydrocarbons, hydroxide compounds, and mixtures thereof. Use of the process for quantitative dissolution and analysis of metals, for destruction and stabilization of metal residues, and for battery recycling is also described.

Description

[Technical Field]

[0001] Related Applications This application claims priority under applicable law to Canadian Patent Application No. 2,996,961, filed March 1, 2018, the entire contents of which are incorporated herein by reference for all purposes.

[0002] Technical Field The present application refers to the fields of quantitative and safe dissolution of alkali metals or alkaline earth metals, destruction and stabilization of alkali metal or alkaline earth metal residues, and recycling of alkali metals or alkaline earth metals. [Background technology]

[0003] background Alkali metals (such as lithium, sodium, and potassium) have similar chemical properties and have highly reducing valence electrons. As a result, they react violently with water to produce potentially explosive hydrogen according to the following reaction: 2M (s) +2H2O (l) →2M + (aq) +2OH - (aq) +H 2(g) (1)

[0004] Alkaline earth metals (such as magnesium, calcium, strontium, and barium) also react with water to produce hydrogen gas according to the following equation: M (s) +2H2O (l) →M 2+ (aq) +2OH - (aq) +H 2(g) (2)

[0005] For this reason, calcium, strontium, and barium react violently in water. In either case, the hydrogen released by these reactions is a highly flammable gas that can be explosive. The lower explosive or flammable limit for hydrogen is 4%, while the upper limit is 75%. In air, hydrogen can ignite instantly within this concentration range. Therefore, there is a risk of explosion and eruptions during hydrogen containment.

[0006] It is possible to dissolve alkali metals by replacing water with methanol, ethanol, or butanol (see Dulski, TR "A Manual for the Chemical Analysis of Metals, ASTM Manual Series MNL 25," Ann Arbor, MI (1996); and Furukawa, T. et al., Nuclear Materials and Energy 9 (2016): 286-291). The alkali metal can then cleave the OH bond to give an alcoholate. For example: CH3-CH2-O-H+Na → CH3-CH2-O - Na + +1 / 2H2(3)

[0007] For storage and transport purposes, alkali metals such as lithium are therefore usually immersed in mineral oil.

[0008] The synthesis of organomagnesium or Grignard reagents involves dissolving magnesium in an anhydrous solvent. For example, the solvent used can be oxolane (tetrahydrofuran) or an ether such as diethyl ether. In the synthesis of Grignard reagents, the solvent serves to solvate and stabilize the organomagnesium compound. The synthesis of Grignard reagents is carried out according to the following reaction: [ka]

[0009] The synthesis of organolithium reagents is similar to that of organomagnesium reagents and involves dissolving lithium in anhydrous reagents and is carried out according to the following reaction: [ka] wherein X is a halogen, such as Br, Cl, or I.

[0010] Water is the most readily available and least expensive oxidizing agent. However, the reaction between water and alkali metals is not suitable for safe dissolution. Therefore, there is an increasing demand for a safe method for aqueous alkali metal dissolution. [Prior art documents] [Non-patent literature]

[0011] [Non-Patent Document 1] Dulski, TR “A Manual for the Chemical Analysis of Metals, ASTM Manual Series MNL 25.” Ann Arbor, MI (1996) [Non-patent document 2] Furukawa, T. et al., Nuclear Materials and Energy 9(2016):286-291 Summary of the Invention [Means for solving the problem]

[0012] overview According to a first aspect, the present description relates to a process for dissolving a metal, wherein the metal is selected from alkali metals, alkaline earth metals, and alloys primarily comprising at least one of these, the process comprising step (a) of contacting the metal with a reaction inhibitor and water, wherein the reaction inhibitor is selected from hydrocarbons, hydroxide compounds, and mixtures comprising at least two of these.

[0013] According to one embodiment, the hydrocarbon has the formula Cn H m where n and m are integers; n is 5 to 40; and m is selected so that the molecule is stable and optionally contains one or more unsaturations.

[0014] According to another embodiment, the hydroxylated compound has the formula R(OH) X wherein R is C 1-8 Alkyl and C 2-3 Alkyl (OC 2-3 alkyl) y It is understood that the hydroxylated compound is selected from the group, x is 1 to 4, y is 1 to 5, and the C:O ratio of said hydroxylated compound is in the range of 1:1 to 3:1.

[0015] According to another embodiment, the hydroxylated compound has the formula R(OH) x wherein R and x are such that said formula defines a polyalkylene glycol having an average molecular weight of 300 to 800 g / mol or a polyvinyl alcohol having an average molecular weight of 7,000 to 101,000 g / mol, optionally substituted with one or more ester groups.

[0016] According to another embodiment, the water is contained in an emulsion of light mineral oil and water.

[0017] According to another embodiment, the present description relates to the process described herein, wherein the inhibitor is a hydroxide of the metal, and step (a) comprises contacting the metal with a concentrated solution of the hydroxide of the metal in water.

[0018] According to another embodiment, the metal is selected from the alkali metals lithium, sodium, and potassium, and alloys containing primarily one of these. For example, the metal is lithium. Or, the metal is an alloy of lithium with magnesium or aluminum, where lithium is the predominant metal. According to another embodiment, the metal is selected from magnesium, calcium, strontium, barium, and alloys containing primarily one of these.

[0019] According to another embodiment, the reaction inhibitor is a hydroxylated compound selected from propylene glycol, glycerol, ethylene glycol, ethanol, dipropylene glycol, tripropylene glycol, polyvinyl alcohol, polyethylene glycol, methoxypolyethylene glycol, and a mixture containing at least two of these. For example, the hydroxylated compound is propylene glycol or lithium hydroxide. According to another embodiment, the reaction inhibitor is a hydrocarbon containing primarily linear, cyclic, or branched alkanes. According to another embodiment, the inhibitor is a mixture containing at least one hydroxylated compound and a hydrocarbon.

[0020] According to another embodiment, the inhibitor is a hydroxide of the metal and step (a) comprises contacting the metal with a concentrated solution of the hydroxide of the metal in water, for example, the hydroxide of the metal is lithium hydroxide.

[0021] According to another embodiment, the high concentration metal hydroxide solution has a concentration of 4 to 12.8% weight / volume (weight / volume % = g / 100 mL). Alternatively, the high concentration metal hydroxide solution has a concentration of 6 to 12.8% weight / volume. Alternatively, the high concentration metal hydroxide solution has a concentration of 8 to 12.8% weight / volume. Alternatively, the high concentration metal hydroxide solution is a saturated solution.

[0022] According to another embodiment, the process involves complete or partial immersion of the metal in the inhibitor followed by the addition of water or an emulsion of light mineral oil and water.

[0023] In one embodiment, the metal to be dissolved is fixed to a non-reactive metal prior to the contacting step.

[0024] According to another aspect, the process is used for quantitative dissolution of metals. According to one embodiment, the process further comprises weighing the metal before contacting. The process can optionally further comprise separating the solution and quantitatively analyzing the solution. Quantitative analysis of the solution can be performed, for example, by inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0025] According to another aspect, the process is used to destroy and stabilize metal residues, for example, metal residues adhering to the surface of a portion of a device. According to another embodiment, the process is performed on the entire device having metal residues adhering thereon.

[0026] According to another aspect, the process is used to recycle batteries. According to another embodiment, the process further comprises disassembling or shredding the batteries prior to contacting. Alternatively, the disassembling or shredding the batteries and the contacting steps are performed simultaneously.

[0027] According to a final embodiment, the process is used to recycle lithium in the form of LiOH or LiOH·H2O, or to recycle converted lithium in the form of Li2CO3 or another lithium salt. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 presents images of the dissolution of the formed pellets, showing (A) the lithium pellet (top metal) fixed to the stainless steel pellet (bottom metal); and (B) the position of the lithium (top metal) in a graduated cylinder for quantitative dissolution of lithium, as described in Example 1(b).

[0029] [Figure 2] FIG. 2 presents an image of the dissolution in mineral oil of a lithium pellet (top metal) fixed to a stainless steel pellet (bottom metal), as described in Example 2.

[0030] [Figure 3] FIG. 3 presents an image of the dissolution of lithium pellets immobilized on stainless steel pellets in saturated lithium hydroxide solution as described in Example 5(a). DETAILED DESCRIPTION OF THE INVENTION

[0031] Detailed Description All technical and scientific terms and expressions used herein have the same definitions as commonly understood by those skilled in the art when they relate to the present technology, although definitions of some of the terms and expressions used are provided below.

[0032] As used herein, the term "about" means approximately, in the region of, and generally. For example, when the term "about" is used in connection with a numerical value, it modifies the value up or down by 10% or 5% of the nominal value. This term can also take into account, for example, experimental error or rounding of the measuring device.

[0033] Where a range of values ​​is recited herein, unless otherwise stated, the lower and upper limits of the range are always included in the definition.

[0034] As used herein, the terms "predominantly" and "predominantly" refer to concentrations greater than 50% v / v or 50% by weight, depending on whether the term is associated with a nominal value by volume or weight, respectively.

[0035] The term "hydrocarbon" as used herein refers to an oil or oil-based mixture that consists exclusively of carbon and hydrogen and therefore does not contain any other substituents. Hydrocarbons comprise primarily linear, cyclic, or branched saturated alkanes. Hydrocarbons can be obtained from the distillation of petroleum. Alternatively, hydrocarbons can be synthetically produced. When hydrocarbons are obtained from the distillation of petroleum, it is understood that in addition to linear, cyclic, or branched saturated alkanes, which remain predominant, the hydrocarbons can also comprise smaller proportions of mixtures of different products, such as partially unsaturated compounds or aromatic compounds, such as benzene and toluene.

[0036] As used herein, the term "hydroxylated compound" refers to an organic or inorganic compound that contains at least one hydroxyl functional group (-OH).

[0037] The term "alkyl" or "alkylene" as used herein refers to a saturated hydrocarbon group having 1 to 8 carbon atoms, including straight-chain or branched-chain groups. Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, and the like. When an alkyl group is located between two functional groups, such as methylene, ethylene, propylene, etc., the term "alkylene" can also be used. i -C ii Alkyl" and "C i -C ii The term "alkylene" refers to an alkyl or alkylene group having "i" to "ii" number of carbon atoms, respectively.

[0038] The present application describes a process for melting a metal, wherein the metal is selected from alkali metals, alkaline earth metals, and alloys containing primarily at least one of these.

[0039] For example, the metal is an alkali metal selected from lithium, sodium, and potassium. The metal can also be an alkaline earth metal selected from magnesium, calcium, strontium, and barium. Or, the metal can be an alloy containing primarily an alkali metal or alkaline earth metal. According to one variant of interest, the metal is lithium. According to another variant of interest, the metal is an alloy of lithium with magnesium or aluminum, where lithium is predominant.

[0040] The process includes contacting the metal with a reaction inhibitor and water, optionally in the form of an emulsion of light mineral oil and water. In the process, the metal is previously immobilized on a non-reactive metal, such as stainless steel. For example, dissolution can be performed on a sample (e.g., a pellet) consisting of a layer of the metal to be dissolved immobilized on a layer of non-reactive metal. The metal to be dissolved is placed on top of the sample to prevent or reduce the risk of released hydrogen accumulating underneath.

[0041] The reaction inhibitor can be selected from hydrocarbons, hydroxylated compounds and mixtures containing at least two of these. In the context of the present description, hydrocarbons are compounds of formula C n H m where n and m are integers; n is 5 to 40; and m is selected so that the molecule is stable and optionally contains one or more unsaturations.

[0042] According to another option, the hydroxylated compound has the formula R(OH) X wherein R is C 1-8 Alkyl and C 2-3 Alkyl (OC 2-3 alkyl) y wherein x is 1 to 4 and y is 1 to 5, it being understood that the C:O molar ratio of said hydroxylated compound is in the range of 1:1 to 3:1. According to a second alternative, the hydroxylated compound has the formula R(OH) xwhere R and x are selected such that the formula defines a polyalkylene glycol having an average molecular weight of 300 to 800 g / mol or a polyvinyl alcohol having an average molecular weight of 7,000 to 101,000 g / mol, optionally substituted with one or more ester groups.

[0043] Non-limiting examples of hydroxylated compounds include propylene glycol, glycerol, ethylene glycol, ethanol, dipropylene glycol, tripropylene glycol, polyvinyl alcohol, polyethylene glycol, methoxypolyethylene glycol, or a mixture comprising at least two thereof.

[0044] For example, the reaction inhibitor is propylene glycol or paraffin oil. According to another variant, the reaction inhibitor is a mixture comprising at least one hydroxylated compound and a hydrocarbon. According to another example, the inhibitor further comprises methanol.

[0045] According to one example, the reaction inhibitor can further include one or more adjuvants or additives to modify or improve its properties, such as its viscosity, etc. For example, the adjuvant can be glucose or another similar compound.

[0046] According to one example, the reaction inhibitor is a mixture containing a hydroxylated compound present at a concentration of 1-99% v / v, preferably 10-80% v / v, or 30-60% v / v, or also about 50% v / v, including upper and lower limits.

[0047] According to another example, the step of contacting the metal with the inhibitor and water (the water optionally being in the form of an emulsion of light mineral oil and water) includes complete or partial immersion of the metal in the inhibitor followed by the addition of water or the emulsion of light mineral oil and water.

[0048] According to another example, the metal is immersed in a volume of reaction inhibitor equal to about 14 μL per gram of metal to be dissolved. Water or a light mineral oil and water emulsion can be added in small, regular intervals, for example, about 0.10 to about 6.0 μL per mg of metal to be dissolved per 15-minute period, including upper and lower limits. Alternatively, the water or light mineral oil and water emulsion can be added continuously and at a controlled, low flow rate, for example, about 0.05% v / v to about 1% v / v per minute, including upper and lower limits.

[0049] By way of another example, water or an emulsion of light mineral oil and water can be added until the solution reaches a water concentration of about 50% v / v to about 90% v / v, or until the metal is completely dissolved.

[0050] According to another variation of interest, the reaction inhibitor of the processes described herein is a metal hydroxide, and step (a) comprises contacting the metal with a concentrated solution of the metal hydroxide in water. For example, the metal hydroxide is lithium hydroxide. For example, the concentrated solution of the metal hydroxide has a concentration of about 4 to about 12.8% weight / volume, or about 6 to about 12.8% weight / volume, or about 8 to about 12.8% weight / volume, the upper and lower limits included. Alternatively, the concentrated solution is a saturated solution.

[0051] According to another aspect, the present description also proposes the use of the process of the present application for quantitative dissolution of metals. For example, the process can further comprise weighing the metal before contacting and quantitatively analyzing the dissolution. The quantitative analysis of the solution can be carried out, for example, by inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0052] According to another aspect, the present description also proposes the use of the present process for the safe destruction and stabilization of metal residues. The present process may, among other things, reduce the reaction rate and release of hydrogen gas, reduce the local hydrogen gas atmosphere, prevent local heating, and / or prevent the lithium melting temperature from being reached. Furthermore, the slower release may, with sufficient ventilation, make it possible to stay below the lower flammability limit of hydrogen gas, which is about 4% by volume.

[0053] Metal residues, such as metallic lithium, may also adhere to the surface of portions of the device. According to one embodiment, the entire device having metal residues thereon is treated with the process of the present application to dissolve or stabilize the metal residues.

[0054] According to another aspect, the present description also proposes the use of the process of the present application for recycling batteries. For example, the process can further include a step of disassembling or shredding the battery before the contacting step. Alternatively, the step of disassembling or shredding the battery can be performed during the contacting step. For example, when using this process, lithium is oxidized in aqueous solution to form LiOH. The lithium can then be recycled from the aqueous LiOH solution in the form of LiOH·H2O, or converted in the form of Li2CO3 or another lithium salt. These compounds can then be used, for example, in the production of liquid, solid, or gel electrolytes, such as LiFePO4, Li4Ti5O 12 , can be reused in the production of electrochemically active materials, such as metallic lithium or lithium salts.

[0055] According to a final embodiment, the reaction inhibitor can also be a lithium hydroxide solution. Solid LiOH is commercially available in its anhydrous form (LiOH) or monohydrate form (LiOH·H2O). The maximum solubility of anhydrous LiOH in water is approximately 128 g / L (a concentration equivalent to approximately 12.8% weight / volume) at a temperature of 20 °C. Dissolution of metallic lithium in concentrated aqueous LiOH occurs very slowly, and therefore, concentrated aqueous LiOH can be used to safely solubilize metallic lithium. The solution resulting from this controlled dissolution can then be used to recover lithium in forms with significant commercial value (such as anhydrous LiOH, LiOH·H2O, or Li2CO3). For example, one advantage of using this inhibitor is its high chemical purity, since no other chemicals are introduced into the process. This inhibitor can also be used in the destruction of metallic lithium residues for the recycling of metallic lithium batteries or for the chemical quantitative analysis of impurities contained in the lithium and / or for the determination of the purity of the lithium. [Example]

[0056] The following examples are provided for illustrative purposes and should not be construed as further limiting the scope of the invention as described.

[0057] Example 1: Quantitative Dissolution of Lithium for Chemical Analysis Using Propylene Glycol as a Reaction Inhibitor (a) Sample preparation The lithium samples to be dissolved were prepared in an anhydrous chamber with a dew point below −40°C. A clean, dry stainless steel pellet was first weighed on an analytical balance and inserted into a pellet mold (e.g., a Specac brilliant spectroscopy™ GS03000 13 mm Evacuable Pellet Die) so that the non-polished surface was in contact with the sample to promote lithium deposition on the stainless steel pellet. The metallic lithium foil was then removed and inserted into the pellet mold. A clean, dry high-molecular-weight polyethylene (UHMW-PE) pellet (12.90 mm × 6.0 mm) was then inserted into the pellet mold so that its polished surface was in contact with the lithium sample, allowing for easy release of the UHMW-PE pellet. The mold was then assembled and placed in a manual hydraulic press (YLJ-15, MTI Corporation). To remove air from the sample, a vacuum line was connected to the base of the pellet mold, and the mold was placed under vacuum for 1 minute. A pressure of 80 bar was applied under vacuum for 1 minute. Once the pressure was released, the vacuum was maintained for an additional minute, so that the lithium pellet thus formed was ultimately between the stainless steel pellet and the UHMW-PE pellet.

[0058] The pellets were then removed from the die using an ejection ring and hydraulic press. During ejection, a cylindrical tool was used to break away the UHMW-PE pellets. The sample was then weighed on an analytical balance, and the weight of the stainless steel pellet was subtracted.

[0059] For comparison, the same procedure was carried out using an alloy containing 90% by weight lithium and 10% magnesium.

[0060] (b) Quantitative dissolution of the sample The lithium or lithium-based alloy pellet thus formed on the stainless steel pellet (see FIG. 1A) was inserted into a 25 mL graduated cylinder. To facilitate the release of hydrogen bubbles during dissolution, the lithium pellet was positioned upward (see FIG. 1B). Dissolution was carried out in the cylinder to obtain a column of liquid that would capture the residual extracted lithium. Using the process of this example, hydrogen release occurs gradually to avoid reaching high local concentrations of flammable hydrogen and limit the temperature increase at the lithium surface, thereby reducing the risk of fire or explosion.

[0061] A volume of 5 mL of propylene glycol was added. To monitor the dissolution reaction, 1 mL of ultrapure water was added every 15 minutes for a period of approximately 6 hours to obtain a total volume of approximately 25 mL of water. The sample was then allowed to react until complete dissolution and no further formation of hydrogen bubbles was observed.

[0062] The resulting solution was transferred to a 50 mL volumetric flask and acidified with 4.15 mL of concentrated hydrochloric acid. Then, highly concentrated solutions of hydrochloric acid (2.50 mL) and nitric acid (2.50 mL) were added (final concentrations of 5% v / v, respectively). The volume of the flask was filled with ultrapure water up to the marked ring mark. The solution was acidified to obtain the same matrix as the standard for ICP-OES analysis.

[0063] (c) Quantitative analysis of impurities contained in lithium, magnesium, and metallic lithium or lithium-based alloys by ICP-OES The solution is then analyzed by ICP-OES. This method allows for the quantification of magnesium and lithium at high concentrations using calibration curves. Therefore, this analysis allows for the quantification of lithium or other elements in lithium-based alloys, among other things. This analysis also allows for the quantification of impurities contained in metallic lithium or lithium-based alloys. Impurities may include, for example, calcium, chromium, iron, potassium, magnesium, manganese, sodium, nickel, silicon, strontium, and / or zinc.

[0064] When this method is used to quantify impurities contained in metallic lithium, blanks and standards are prepared using the same concentrations of propylene glycol and lithium as in the sample to be analyzed in order to obtain the same matrix as the sample to be analyzed (matrix matching).

[0065] Example 2: Quantitative Dissolution of Lithium for Chemical Analysis Using Mineral Oil as a Reaction Inhibitor A lithium sample was prepared according to the method shown in Example 1(a). The sample was then dissolved according to the method shown in Example 1(b) by replacing propylene glycol with light mineral oil. Also in this example, a lithium pellet was placed in a graduated cylinder. The lithium was positioned upward to promote the release of hydrogen bubbles. Light mineral oil was then added to completely immerse the lithium pellet. Ultrapure water or an emulsion of ultrapure water and mineral oil was gradually added to control the oxidation reaction of metallic lithium and the evolution of hydrogen. The solution was then allowed to settle and decanted. ICP-OES analysis was then performed.

[0066] Dissolution of lithium pellets (top metal) fixed to stainless steel pellets (bottom metal) in mineral oil was carried out (see Figure 2). Upon addition of water or a water-oil emulsion, it was possible to observe the formation of a white precipitate of lithium hydroxide, which is not soluble in mineral oil (see Figure 2). The use of mineral oil as a reaction inhibitor allows for the slow release of flammable hydrogen without local temperature increases, thereby improving the safety of the process.

[0067] Example 3: Safe destruction and stabilization of lithium residues The reaction inhibitor can be used to safely destroy and stabilize residues of alkali metals, alkaline earth metals, and alloys containing at least one of these, which may or may not be attached to parts of the device.

[0068] For example, metallic lithium adhering to a portion of a device is removed. The entire device is immersed in a cleaning solution containing propylene glycol and water in a volume ratio of 1:1, taking into account the amount of metallic lithium to be dissolved. The alkali metal removal process is considered complete when the formation of hydrogen bubbles has ceased, thus indicating complete dissolution of metallic lithium in the form of lithium hydroxide (LiOH), according to the following reaction equation: 2Li+2H2O→2LiOH+H2(6)

[0069] The process described in this example makes it possible to slow down the reaction and H2 release rate, reduce the local concentration of flammable H2, avoid local heating, and avoid reaching the melting temperature of Li. The slower release makes it possible to stay below the lower flammability limit of hydrogen gas, which is about 4% by volume, and therefore to safely destroy the residue.

[0070] Example 4: Recycling lithium in lithium metal batteries In order to recover and / or recycle commercially valuable materials, inhibitors can be used to deactivate lithium or lithium-based alloys contained in primary or secondary batteries. For example, a recycling process involves shredding the batteries by crushing them in the presence of an aqueous solution containing an organic inhibitor. When using this process, lithium oxidizes in the aqueous solution to form LiOH. Once the lithium has completely dissolved in this form, the shredded (non-reactive) material is rinsed with water to remove traces of LiOH. The lithium can then be recycled from the aqueous solution of LiOH in the form of LiOH·HO, or converted in the form of LiCO or another lithium salt. These compounds can then be converted into lithium compounds, e.g., LiFePO, LiTiO, LiFePO4 ... 12 Alternatively, it can be recycled for the production of electrochemically active materials such as metallic lithium, or for the production of lithium salts used in the production of liquid, solid or gel electrolytes.

[0071] Example 5: Controlled dissolution of metallic lithium in lithium hydroxide solution The reaction inhibitor can also be a highly concentrated solution of lithium hydroxide. Dissolution of metallic lithium in concentrated aqueous LiOH occurs very slowly and can therefore be used to safely solubilize metallic lithium. The solution resulting from this controlled dissolution can then be used to recover lithium in forms with significant commercial value (such as anhydrous LiOH, LiOH·H2O, or Li2CO3). This inhibitor can also be used for the destruction of metallic lithium residues, for the recycling of metallic lithium batteries, or for the chemical quantitative analysis of impurities contained in lithium.

[0072] (a) Dissolution of lithium hydroxide in saturated solution Controlled dissolution of the metallic lithium sample prepared in Example 1(a) was performed by first adding 5 mL of a saturated solution of lithium hydroxide (12.8% wt / vol). Water was then added gradually in small amounts at regular intervals (approximately 1 mL / 15 min for 0.350 g of metal) to control the rate of metal dissolution. A total of 18 mL of water was added to complete the dissolution reaction, corresponding to a final concentration of 8.03% wt / vol.

[0073] Figure 3 shows an image of the controlled dissolution of metallic lithium in saturated lithium hydroxide solution (12.8% wt / vol LiOH) as described in this example. As described in Example 1(a), metallic lithium was held at the bottom of the solution by a stainless steel pellet onto which the metal was pressed. Using the process of this example, hydrogen evolution occurs slowly and the lithium does not heat up.

[0074] (b) Dissolution of lithium hydroxide in an unsaturated solution (6.4% wt / vol LiOH). Controlled dissolution of metallic lithium sample, as prepared in Example 1(a), was carried out according to the method described in Example 5(a), except that the saturated solution of LiOH was replaced with 5 mL of a solution containing 6.4% wt / vol LiOH (64 g / L). Using the process of this example, the reaction is more vigorous and faster. The solution heats up slightly, and hydrogen evolution is more pronounced. To complete the lithium dissolution reaction, a total of 14 mL of water was added in small increments at regular intervals (i.e., approximately 1 mL of water per 15 minutes for 0.350 g of metal). The resulting final concentration was 8.04% wt / vol.

[0075] Numerous modifications could be made to one or other of the above-described embodiments without departing from the contemplated scope of the invention. All references, patents or scientific literature documents mentioned in this document are incorporated herein by reference in their entirety for all purposes. According to a preferred embodiment of the present invention, for example, the following is provided: (Section 1) 1. A process for melting a metal, wherein the metal is selected from alkali metals, alkaline earth metals, and alloys containing primarily at least one of these, the process comprising: a) contacting the metal with a reaction inhibitor and water Including, The process wherein the reaction inhibitor is selected from hydrocarbons, hydroxylated compounds, and mixtures comprising at least two of these. (Section 2) Item 1, wherein the metal is selected from lithium, sodium, potassium, and alloys containing primarily one of these. (Section 3) 3. The process according to claim 1 or 2, wherein the metal is lithium. (Section 4) 3. The process according to claim 1 or 2, wherein the metal is an alloy of lithium with magnesium or aluminum, with lithium being predominant. (Section 5) Item 1. The process according to item 1, wherein the metal is selected from magnesium, calcium, strontium, barium, and alloys containing primarily one of these. (Section 6) The hydroxylated compound has the formula R(OH) X wherein R is C 1-8 Alkyl and C 2-3 Alkyl (OC 2-3 alkyl) y

[0023] The process according to any one of the above items 1 to 5, wherein x is selected from the group consisting of 1 to 4, y is selected from the group consisting of 1 to 5, and it is understood that the C:O ratio of the hydroxylated compound is in the range of 1:1 to 3:1. (Section 7) The hydroxylated compound has the formula R(OH) x wherein R and x are such that the formula defines a polyalkylene glycol having an average molecular weight of 300 g / mol to 800 g / mol or a polyvinyl alcohol having an average molecular weight of 7,000 g / mol to 101,000 g / mol, optionally substituted with one or more ester groups. (Section 8) 8. The process according to item 6 or 7, wherein the hydroxylated compound is selected from propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, ethylene glycol, ethanol, polyvinyl alcohol, polyethylene glycol (PEG), methoxypolyethylene glycol (MEG), and a mixture comprising at least two of these. (Section 9) 9. The process according to any one of items 1 to 8, wherein the reaction inhibitor comprises propylene glycol. (Section 10) 10. The process according to any one of items 1 to 9, wherein the reaction inhibitor further comprises methanol. (Section 11) 11. The process according to any one of items 1 to 10, wherein the reaction inhibitor is a mixture containing a hydroxylated compound present at a concentration of 1% v / v to 99% v / v. (Section 12) Item 12. The process according to item 11, wherein the concentration is 10% v / v to 80% v / v. (Section 13) Item 13. The process according to item 12, wherein the concentration is 30% v / v to 60% v / v. (Section 14) 14. The process according to claim 13, wherein the concentration is about 50% v / v. (Section 15) The hydrocarbon has formula C nH m wherein n and m are integers; n is 5 to 40; and m is selected so that the molecule is stable and optionally contains one or more unsaturations. (Section 16) 16. The process of claim 15, wherein the hydrocarbons comprise primarily linear, cyclic, or branched alkanes. (Section 17) 17. The process of any one of paragraphs 1 to 16, wherein the inhibitor is a mixture comprising at least one hydroxylated compound and a hydrocarbon. (Section 18) 18. The process of any one of paragraphs 1 to 17, wherein the water is contained in an emulsion of light mineral oil and water. (Section 19) 18. The process of any one of paragraphs 1 to 17, wherein step (a) comprises the addition of water or an emulsion of light mineral oil and water after complete or partial immersion of the metal in the inhibitor. (Section 20) 20. The process of claim 19, wherein the water or the emulsion of light mineral oil and water is added continuously and at a controlled slow rate, for example, from about 0.05% v / v / min to about 1% v / v / min. (Section 21) 20. The process of claim 19, wherein the water or the emulsion of light mineral oil and water is added in small amounts at regular intervals, for example, in amounts of 0.10 μL to 6.0 μL per mg of metal to be dissolved per 15 minute period. (Section 22) 22. The process of claim 20 or 21, wherein the water or the emulsion of light mineral oil and water is added until the solution reaches a water concentration of 50% v / v to 90% v / v or until the metal is completely dissolved. (Section 23) 6. The process according to any one of items 1 to 5, wherein the reaction inhibitor is a hydroxide of the metal, and step (a) comprises contacting the metal with a concentrated solution of the hydroxide of the metal in water. (Section 24) 24. The process of claim 23, wherein the highly concentrated solution of the hydroxide of the metal is a solution of lithium hydroxide in water having a concentration of 4% wt / vol to 12.8% wt / vol. (Section 25) 25. The process according to item 24, wherein the concentration is 6% weight / volume to 12.8% weight / volume. (Section 26) 26. The process according to item 25, wherein the concentration is 8% weight / volume to 12.8% weight / volume. (Section 27) 27. The process according to any one of items 23 to 26, wherein the high concentration solution is a saturated solution. (Section 28) 28. The process according to any one of paragraphs 1 to 27, wherein the metal is immobilized on a non-reactive metal prior to the contacting step. (Section 29) 29. The process according to any one of the above paragraphs 1 to 28, wherein the dissolution is quantitative. (Section 30) wherein step (a) further comprises weighing the metal prior to the contacting; The process comprises: (b) optionally separating the solution; and (c) quantitatively analyzing said solution; 30. The process according to claim 29, further comprising: (Section 31) 31. The process according to claim 30, wherein step (c) is carried out by inductively coupled plasma optical emission spectroscopy (ICP-OES). (Section 32) 28. The process according to any one of items 1 to 27, wherein the metal is in the form of a metal residue adhering to the surface of a portion of the apparatus. (Section 33) 33. The process according to claim 32, wherein step (a) is carried out on the entire device having metal residue attached thereto. (Section 34) 34. The process according to paragraph 32 or 33, used for the destruction and stabilization of metal residues. (Section 35) 28. The process according to any one of the above items 1 to 27, which is used to recycle batteries. (Section 36) 36. The process according to claim 35, further comprising the step of disassembling or shredding the battery prior to the contacting step. (Section 37) 36. The process of claim 35, further comprising disassembling or shredding the battery during the contacting step. (Section 38) 38. A process for recycling lithium, comprising the steps of the process according to any one of items 1 to 37, wherein the lithium is LiOH or LiOH·H 2 Recycled in the form of O or Li 2 CO 3 or converted into another form of lithium salt, a process.

Claims

1. 1. A process for melting a metal, wherein the metal is selected from alkali metals, alkaline earth metals and alloys containing primarily at least one of these, the process comprising, in sequence: a) completely or partially immersing the metal in an inhibitor; b) adding water Including, wherein the reaction inhibitor is selected from a hydroxylated compound, a mixture comprising at least two hydroxylated compounds, and a mixture comprising at least one hydrocarbon and at least one hydroxylated compound; and wherein the hydroxylated compound is: ・Formula R(OH) ｘ wherein R is C １－８ Alkyl and C ２－３ Alkyl (OC ２－３ alkyl) ｙ wherein x is 2 to 4 and y is 1 to 5, and it is understood that the C:O ratio of said hydroxylated compound is in the range of 1:1 to 3:1; ・Formula R(OH) ｘ wherein R and x are such that the formula defines a polyalkylene glycol having an average molecular weight of 300 g / mol to 800 g / mol or a polyvinyl alcohol having an average molecular weight of 7,000 g / mol to 101,000 g / mol, wherein the polyalkylene glycol or polyvinyl alcohol is unsubstituted or substituted with one or more ester groups; and a hydroxide of said metal present in a concentrated solution of said hydroxide of said metal in water, wherein said concentrated solution is a saturated solution, or wherein said metal is lithium and said concentrated solution has a concentration of between 4% weight / volume and 12.8% weight / volume. Selected from: process.

2. 2. The process of claim 1, wherein the metal is selected from lithium, sodium, potassium, and alloys containing primarily one of these.

3. 3. The process of claim 1 or 2, wherein the metal is lithium.

4. 3. The process of claim 1 or 2, wherein the metal is an alloy of lithium with magnesium or aluminum, with lithium predominating.

5. 2. The process of claim 1, wherein the metal is selected from magnesium, calcium, strontium, barium, and alloys containing predominantly one of these.

6. 6. The process of any one of claims 1 to 5, wherein the hydroxylated compound is selected from propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, ethylene glycol, polyvinyl alcohol, polyethylene glycol (PEG), methoxypolyethylene glycol (MEG), and mixtures comprising at least two thereof.

7. The process of any one of claims 1 to 6, wherein the reaction inhibitor comprises propylene glycol.

8. The process of any one of claims 1 to 7, wherein the reaction inhibitor further comprises methanol.

9. 9. The process of any one of claims 1 to 8, wherein the reaction inhibitor is a mixture comprising a hydroxylated compound and a hydrocarbon, wherein the hydroxylated compound is present at a concentration of 1% v / v to 99% v / v based on the total volume of the reaction inhibitor.

10. 10. The process of claim 9, wherein the concentration is between 10% v / v and 80% v / v.

11. 11. The process of claim 10, wherein the concentration is between 30% v / v and 60% v / v.

12. 12. The process of claim 11, wherein the concentration is 50% v / v.

13. The hydrocarbon is of formula C ｎ H ｍ wherein n and m are integers; n is from 5 to 40; and m is selected in view of n such that the hydrocarbon is saturated or partially unsaturated and contains one or more unsaturations.

14. 14. The process of claim 13, wherein the hydrocarbons comprise primarily straight-chain, cyclic, or branched-chain alkanes.

15. 15. The process of any one of claims 1 to 14, wherein the reaction inhibitor is a mixture comprising at least one hydrocarbon and at least one hydroxylated compound.

16. The process of any one of claims 1 to 15, wherein the water is contained in an emulsion of light mineral oil and water.

17. The process of any one of claims 1 to 15, wherein the water is added continuously and at a controlled slow rate.

18. 17. The process of claim 16, wherein the light mineral oil and water emulsion is added continuously and at a controlled slow rate.

19. 19. The process of claim 17 or 18, wherein the addition is carried out at a rate of 0.05% v / v / min to 1% v / v / min of the total volume to be added.

20. The process of any one of claims 1 to 15, wherein the water is added in small amounts at regular intervals.

21. 17. The process of claim 16, wherein the light mineral oil and water emulsion is added in small amounts at regular intervals.

22. 22. The process of claim 20 or 21, wherein the addition is in an amount of 0.10 μL to 6.0 μL per mg of metal to be dissolved per 15 minute period.

23. 23. The process of any one of claims 17 to 22, wherein the addition is carried out until the mixture of water and reaction inhibitor reaches a water concentration of 50% v / v to 90% v / v in the total volume of the mixture or until the metal is completely dissolved.

24. 6. The process of any one of claims 1 to 5, wherein the metal is lithium and the reaction inhibitor is lithium hydroxide present in a concentrated solution of lithium hydroxide in water having a concentration of 4% weight / volume to 12.8% weight / volume, and step (a) comprises contacting the metal with the concentrated solution of lithium hydroxide in water.

25. 25. The process of claim 24, wherein the concentration is between 6% weight / volume and 12.8% weight / volume.

26. 26. The process of claim 25, wherein the concentration is between 8% weight / volume and 12.8% weight / volume.

27. 6. The process of any one of claims 1 to 5, wherein the metal is lithium and the reaction inhibitor is lithium hydroxide present in a saturated solution of lithium hydroxide in water, and step (a) comprises contacting the metal with the saturated solution of lithium hydroxide in water.

28. 28. The process of any one of claims 1 to 27, wherein prior to the immersion step, the metal is fixed to a non-reactive metal, wherein the non-reactive metal is inert under process conditions.

29. The process of any one of claims 1 to 28, wherein the dissolution is complete.

30. wherein step (a) further comprises weighing the metal prior to the immersion; The process comprises: (c) optionally separating the solution obtained in step (b) by dissolving the metal; and (d) quantitative analysis of the metals dissolved in the solution; 30. The process of claim 29, further comprising:

31. 31. The process of claim 30, wherein step (d) is carried out by inductively coupled plasma optical emission spectroscopy (ICP-OES).

32. A process according to any one of claims 1 to 31, wherein the metal is in the form of a metal residue adhering to the surface of the part of the apparatus after contact with the metal.

33. 33. The process of claim 32, wherein step (a) is performed on the entire device having the metal residue attached thereto.

34. The process of any one of claims 1 to 27, used for recycling batteries.

35. 35. The process of claim 34, further comprising disassembling or shredding the battery prior to said soaking step.

36. 35. The process of claim 34, further comprising disassembling or shredding the battery during the soaking step.

37. A process for recycling lithium comprising the steps of the process of any one of claims 1 to 36, wherein the lithium is LiOH or LiOH.H ２ O or recycled in the form of Li ２ CO ３ or converted into another form of lithium salt, a process.

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