Method for producing metal fluoride and composition

Abstract

To provide a method for producing a metal fluoride by which the metal fluoride can be produced while suppressing the generation of corrosive gas, and to provide a composition.SOLUTION: A method for producing a metal fluoride, comprising a step (1) of mechanochemically treating a fluorine-containing compound and a basic metal compound containing at least one member selected from the group consisting of alkali metals and alkaline earth metals to obtain a composition containing the fluorine-containing compound and the basic metal compound, and a step (2) of heat-treating the composition to obtain a metal fluoride containing at least one member selected from the group consisting of alkali metals and alkaline earth metals.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to methods and compositions for producing metal fluorides. [Background technology]

[0002] After mixing the compression-molded polytetrafluoroethylene with calcium oxide, 400 to 500 kg / cm 2 A method for obtaining calcium fluoride by heating the mixture at 390 to 410° C. under a pressure of 1000 kJ / cm 2 is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Russian Patent No. 2656488 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional method has a problem in that a large amount of corrosive gas such as hydrogen fluoride is generated during heating.

[0005] An object of the present disclosure is to provide a method for producing a metal fluoride and a composition that can produce a metal fluoride while suppressing the generation of corrosive gases. [Means for solving the problem]

[0006] The present disclosure (1) is a method for producing a metal fluoride, comprising: a step (1) of mechanochemically treating a fluorine-containing compound and a basic metal compound containing at least one selected from the group consisting of alkali metals and alkaline earth metals to obtain a composition containing the fluorine-containing compound and the basic metal compound; and a step (2) of heat-treating the composition to obtain a metal fluoride containing at least one selected from the group consisting of alkali metals and alkaline earth metals.

[0007] The present disclosure (2) is the production method according to the present disclosure (1), wherein the energy in the mechanochemical treatment is 0.1 J / s / g or more.

[0008] The present disclosure (3) is the production method according to the present disclosure (1) or (2), wherein the energy in the mechanochemical treatment is 0.5 to 10 J / s / g.

[0009] The present disclosure (4) is a production method of any combination with any of the present disclosures (1) to (3), in which the cumulative energy in the mechanochemical treatment is 3000 J / g or more.

[0010] The present disclosure (5) is a production method of any combination with any of the present disclosures (1) to (4), in which the cumulative energy in the mechanochemical treatment is 3800 to 400000 J / g.

[0011] The present disclosure (6) is a manufacturing method in which the mechanochemical treatment is carried out using a planetary mill or a vibrating mill, and is any combination of this method with any of the present disclosures (1) to (5).

[0012] The present disclosure (7) is a manufacturing method of any combination with any of the present disclosures (1) to (6), in which the temperature of the heat treatment is 300° C. or higher.

[0013] The present disclosure (8) is a manufacturing method in any combination with any of the present disclosures (1) to (7), in which the temperature of the heat treatment is 300 to 800°C.

[0014] The present disclosure (9) is a manufacturing method of any combination with any of the present disclosures (1) to (8), in which the heat treatment time is 10 minutes to 100 hours.

[0015] The present disclosure (10) is a method for producing any combination of the present disclosures (1) to (9), in which the basic metal compound is at least one selected from the group consisting of a basic metal oxide, a basic metal hydroxide, and a basic metal carbonate.

[0016] The present disclosure (11) is a method for producing any combination of the present disclosures (1) to (10), in which the basic metal compound is a basic metal compound containing magnesium or calcium.

[0017] The present disclosure (12) is a method for producing any combination of the present disclosures (1) to (11), in which the basic metal compound is at least one selected from the group consisting of calcium carbonate, calcium oxide, calcium hydroxide, magnesium oxide, and magnesium hydroxide.

[0018] The present disclosure (13) is a method for producing an arbitrary combination of the present disclosures (1) to (12) in which the fluorine-containing compound is a fluorine-containing polymer.

[0019] The present disclosure (14) is a method for producing any combination of the present disclosures (1) to (13), in which the fluorine-containing compound is at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, polydifluoroethylene, ethylene / tetrafluoroethylene copolymer, and fluororubber.

[0020] The present disclosure (15) is a method for producing any combination of the present disclosures (1) to (14), in which the mixing ratio of the basic metal compound is 1 to 10 equivalents per equivalent of the fluorine-containing compound.

[0021] The present disclosure (16) is a method for producing any combination of the present disclosures (1) to (15), in which the mixing ratio of the basic metal compound is 1 to 4 equivalents per equivalent of the fluorine-containing compound.

[0022] The present disclosure (17) is a composition comprising a fluorine-containing compound and a basic metal compound containing at least one selected from the group consisting of alkali metals and alkaline earth metals, wherein the amount of fluoride ions generated when heated at 600°C for 1 hour is 15 mass% or less relative to the fluorine-containing compound, and the basic metal compound is at least one selected from the group consisting of basic metal carbonates and basic metal hydroxides.

[0023] The present disclosure (18) is the composition according to the present disclosure (17), in which the content of the fluorine-containing compound is 10% by mass or more.

[0024] The present disclosure (19) is the composition according to the present disclosure (17) or (18), wherein the content of the fluorine-containing compound is 10 to 40 mass %.

[0025] The present disclosure (20) is a composition in any combination with any of the present disclosures (17) to (19), in which the content of the basic metal compound is 65 to 90 mass %.

[0026] The present disclosure (21) is a composition in any combination with any of the present disclosures (17) to (20), in which the ratio of the mass loss at 500°C to the mass loss at 600°C is 25% or more when thermogravimetric analysis is performed at a heating rate of 10°C / min.

[0027] The present disclosure (22) is a composition in any combination with any of the present disclosures (17) to (21) in which the fluorine-containing compound is a fluorine-containing polymer.

[0028] The present disclosure (23) is a composition in any combination with any of the present disclosures (17) to (22), in which the fluorine-containing compound is at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, polydifluoroethylene, ethylene / tetrafluoroethylene copolymer, and fluororubber.

[0029] The present disclosure (24) is a composition in any combination with any of the present disclosures (17) to (23), in which the basic metal compound is at least one selected from the group consisting of calcium carbonate, calcium oxide, calcium hydroxide, magnesium oxide, and magnesium hydroxide.

[0030] The present disclosure (25) is a composition for use as a foaming inhibitor, which is an optional combination with any of the present disclosures (17) to (24). [Effects of the Invention]

[0031] According to the present disclosure, it is possible to provide a method for producing a metal fluoride and a composition that can produce a metal fluoride while suppressing the generation of corrosive gases. DETAILED DESCRIPTION OF THE INVENTION

[0032] The present disclosure will be specifically described below.

[0033] The present disclosure relates to a method for producing a metal fluoride, comprising: a step (1) of mechanochemically treating a fluorine-containing compound and a basic metal compound containing at least one selected from the group consisting of alkali metals and alkaline earth metals to obtain a composition containing the fluorine-containing compound and the basic metal compound; and a step (2) of heat-treating the composition to obtain a metal fluoride containing at least one selected from the group consisting of alkali metals and alkaline earth metals.

[0034] In the production method of the present disclosure, since the heat treatment is performed after the mechanochemical treatment, it is possible to suppress the generation of corrosive gases such as hydrogen fluoride. It is presumed that the mechanochemical treatment causes the fluorine-containing compound and the basic metal compound to form aggregates of fine particles, which increases the contact area between the fluorine-containing compound and the basic metal compound and suppresses the generation of corrosive gases. According to the production method of the present disclosure, metal fluorides can be produced without using highly corrosion-resistant equipment. Furthermore, since high-pressure treatment is not required and production can be performed using general-purpose equipment, industrialization is easy.

[0035] The fluorine-containing compound used in the production method of the present disclosure may be any compound having a fluorine atom, excluding metal fluorides. The fluorine-containing compound may be a compound having a fluorine atom bonded to a carbon atom, and is preferably an organic compound having a fluorine atom bonded to a carbon atom. The fluorine-containing compound is preferably a solid at 25° C., since this facilitates mechanochemical treatment.

[0036] The fluorine-containing compound is preferably a fluorine-containing polymer compound, more preferably a fluorine-containing polymer. The molecular weight of the fluorine-containing polymer compound is usually more than 2000, and can be measured by a known method depending on the type of compound.

[0037] The fluorine-containing polymer preferably contains polymerization units based on at least one monomer selected from the group consisting of tetrafluoroethylene [TFE], difluoroethylene, chlorotrifluoroethylene [CTFE], hexafluoropropylene [HFP], trifluoroethylene, and monofluoroethylene, more preferably contains polymerization units based on at least one monomer selected from the group consisting of TFE, difluoroethylene, and CTFE, further preferably contains polymerization units based on at least one monomer selected from the group consisting of TFE and VdF, and even more preferably contains polymerization units based on TFE. Examples of the difluoroethylene include vinylidene fluoride [VdF] and 1,2-difluoroethylene.

[0038] The fluorine-containing polymer may be a fluororesin or a fluororubber, but is preferably a fluororesin.

[0039] Examples of the fluororesin include polytetrafluoroethylene [PTFE], tetrafluoroethylene [TFE] / perfluoro(alkyl vinyl ether) [PAVE] copolymer [PFA], TFE / hexafluoropropylene [HFP] copolymer [FEP], ethylene [Et] / TFE copolymer [ETFE], Et / TFE / HFP copolymer [EFEP], polychlorotrifluoroethylene [PCTFE], chlorotrifluoroethylene [CTFE] / TFE copolymer, CTFE / TFE / PAVE copolymer, Et / CTFE copolymer, polyfluoro Examples of the perfluoroalkyl aryl ether include vinyl fluoride [PVF], polydifluoroethylene (such as polyvinylidene fluoride [PVdF] and poly(1,2-difluoroethylene)), vinylidene fluoride [VdF] / TFE copolymer, VdF / HFP copolymer, VdF / TFE / HFP copolymer, VdF / HFP / (meth)acrylic acid copolymer, VdF / CTFE copolymer, VdF / pentafluoropropylene copolymer, VdF / PAVE / TFE copolymer, and TFE / perfluoroalkyl aryl ether copolymer, which can be used alone or in combination. The perfluoroalkyl aryl ether is CF2=CFCF2-O-Rf 1 (Rf 1 is a monomer represented by a perfluoroalkyl group having 1 to 5 carbon atoms.

[0040] The fluororesin may be a fluororesin having a monomer unit having a C-H bond, or may be a perhalopolymer, preferably a perfluoropolymer, in which halogen atoms are bonded to all of the carbon atoms constituting the main chain of the polymer.

[0041] Examples of the fluororubber include vinylidene fluoride [VdF]-based fluororubbers, tetrafluoroethylene [TFE] / propylene [Pr]-based fluororubbers, TFE / Pr / VdF-based fluororubbers, ethylene [Et] / hexafluoropropylene [HFP]-based fluororubbers, Et / HFP / VdF-based fluororubbers, Et / HFP / TFE-based fluororubbers, fluorosilicone-based fluororubbers, and fluorophosphazene-based fluororubbers, and these may be used alone or in combination.

[0042] Examples of the VdF-based fluororubbers include VdF / HFP copolymer, VdF / TFE / HFP copolymer, VdF / chlorotrifluoroethylene [CTFE] copolymer, VdF / CTFE / TFE copolymer, VdF / perfluoro(alkyl vinyl ether) [PAVE] copolymer, VdF / TFE / PAVE copolymer, VdF / HFP / PAVE copolymer, VdF / HFP / TFE / PAVE copolymer, VdF / TFE / Pr copolymer, VdF / Et / HFP copolymer, and VdF / copolymer of a fluorine-containing monomer represented by the following formula (1): Formula (1): CH2=CFRf 2 (1) (In the formula, Rf 2 is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms)

[0043] The fluoropolymer is preferably at least one selected from the group consisting of PTFE, PFA, FEP, polydifluoroethylene, ETFE, and fluororubber, more preferably at least one selected from the group consisting of PTFE, PFA, FEP, PVdF, ETFE, and fluororubber, and even more preferably at least one selected from the group consisting of PTFE, PFA, FEP, PVdF, ETFE, and VdF-based fluororubber. The fluorine-containing polymer is preferably a fluororesin, more preferably at least one selected from the group consisting of PTFE, PFA, FEP, PVdF, and ETFE, even more preferably at least one selected from the group consisting of PTFE, PVdF, and ETFE, even more preferably at least one selected from the group consisting of PTFE and PVdF, and even more preferably PTFE. As the fluorine-containing polymer, from the viewpoint of reactivity, a fluororesin having a monomer unit having a C—H bond is also preferred, at least one selected from the group consisting of PVdF and ETFE is more preferred, and PVdF is even more preferred.

[0044] The fluorine-containing compound does not have to be a polymer as long as it is solid at 25°C, and may be a fluorine-containing low-molecular-weight compound. The fluorine-containing low molecular weight compound may have a molecular weight of not more than 2000. The molecular weight of the fluorine-containing low molecular weight compound can be determined by calculation from the chemical formula.

[0045] The fluorine-containing low molecular weight compound is preferably a fluorine-based telomer. Examples of the fluorine-based telomer include those represented by the following formula: C2F5(CF2CF2) n -X (wherein X is a halogen atom, and n is an integer of 5 or more) is exemplified. In the above formula, X may be a halogen atom other than a fluorine atom, and is preferably a chlorine atom, a bromine atom, or an iodine atom, more preferably a bromine atom or an iodine atom, and even more preferably an iodine atom. In the above formula, n is an integer of 5 or more and preferably an integer of 10 or less.

[0046] The fluorine-containing low molecular weight compound is represented by the following general formula (I): Y-(CF2) x1 -(CH2) y1 -A (I) (In the formula, Y represents H or F, x1 represents an integer of 4 or more, y1 represents an integer of 0 to 3, and A represents -SO3M I or -COOM I indicates M I represents H, NH4, Li, Na, Mg, Al, K or Ca), and a compound (I) represented by the following general formula (II): F-(CF2) x2 O(CFXCF2O) y2 -CFX-A (II) (In the formula, x2 represents an integer of 1 or more, y2 represents an integer of 0 to 10, X represents F or CF3, and A represents -SO3M II or -COOM II indicates M IIrepresents H, NH4, Li, Na, Mg, Al, K or Ca.

[0047] The compound (I) may be a fluorocarboxylic acid or a salt thereof, such as a perfluorocarboxylic acid or a salt thereof, for example, an ammonium salt or a sodium salt. Compound (I) also includes fluorosulfonic acid and its salts, such as perfluorosulfonic acid and its salts, including ammonium salts and sodium salts. Examples of the compound (II) include perfluoroethercarboxylic acids and salts thereof, such as 2,3,3,3-tetrafluoro-2-[1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy]-propanoic acid.

[0048] The fluorine-containing low molecular weight compound may be adsorbed onto an adsorbent. In this embodiment, the solid in which the fluorine-containing low molecular weight compound is adsorbed onto the adsorbent may be subjected to mechanochemical treatment. The adsorbent is not limited as long as it is a solid capable of adsorbing the fluorine-containing low-molecular-weight compound, but is preferably at least one selected from the group consisting of activated carbon, silica gel, clay, metal-organic framework (MOF), and zeolite.

[0049] In the production method of the present disclosure, a composition containing the fluorine-containing compound and other components may be subjected to mechanochemical treatment. The other components can be used within a range that does not impair the effects of the manufacturing method of the present disclosure. Examples of the other components include general fillers, polymers, and the above-mentioned adsorbents.

[0050] Examples of the common filler include inorganic fillers such as glass fiber, glass beads, carbon fiber, spherical carbon, carbon black, graphite, silica, alumina, mica, silicon carbide, boron nitride, aluminum nitride, titanium oxide, bismuth oxide, cobalt oxide, magnesium oxide, molybdenum disulfide, bronze, gold, silver, copper, nickel, aluminum fluoride, carbon fluoride, and carbon black.

[0051] Examples of the common polymers include polyolefin resins such as polyethylene and polypropylene; polyamide (PA) resins such as nylon 6, nylon 11, nylon 12, nylon 46, nylon 66, nylon 610, nylon 612, and nylon MXD6; polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyarylate, aromatic polyesters (including liquid crystal polyesters), and polycarbonate (PC); polyacetal (POM) resins; polyether resins such as polyphenylene oxide (PPO), modified polyphenylene ether, and polyether ether ketone (PEEK); polyamide-imide (PAI) resins such as polyaminobismaleimide; polysulfone resins such as polysulfone (PSF) and polyethersulfone (PES); vinyl polymers such as ABS resin and poly-4-methylpentene-1 (TPX resin), as well as polyphenylene sulfide (PPS), polyketone sulfide, polyetherimide, polyimide (PI), and epoxy resins. The nylon MXD6 is a crystalline polycondensate obtained from metaxylenediamine (MXD) and adipic acid. The general polymer may be a non-fluorine-containing polymer.

[0052] The content of the above other components may be 50% by mass or less, preferably 30% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, relative to the composition, and may be 0% by mass or more, 0.01% by mass or more, 0.1% by mass or more, or 1% by mass or more.

[0053] The fluorine-containing compound (or the composition when the other components are present; the same applies hereinafter) may be in the form of a powder, a molded product, or waste material from the manufacturing process or after use of a product. It may also be one that has been heated once to above its melting point. If necessary, the fluorine-containing compound may be pulverized before use.

[0054] The shape of the fluorine-containing compound is not particularly limited and may be powder, sheet, block, pellet, flake, or the like, but from the viewpoint of reaction efficiency, it is preferably in the form of a sheet, block, pellet, or flake, more preferably in the form of a sheet, block, or pellet, even more preferably in the form of a sheet or block, and even more preferably in the form of a block. Powder or flake is also preferred.

[0055] Although the size of the fluorine-containing compound is not particularly limited, it has been found that a certain degree of size increase in reaction efficiency. Generally, the smaller the size, the higher the reaction efficiency tends to be, so this finding is unexpected. Of the three dimensions that represent the size of the fluorine-containing compound, the length of at least one dimension may be 0.001 mm or more, preferably 0.010 mm or more, more preferably 0.100 mm or more, even more preferably 1.0 mm or more, even more preferably 2.0 mm or more, and particularly preferably 3.0 mm or more, and is preferably 20 mm or less, more preferably 10 mm or less, even more preferably 5.0 mm or less, and even more preferably 4.0 mm or less. Of the three dimensions that represent the size of the fluorine-containing compound, the length of the shortest dimension is preferably within the above range. Furthermore, it is more preferable that the length of at least two of the three dimensions that represent the size of the fluorine-containing compound is within the above range, and it is even more preferable that the length of the third dimension is within the above range. The length of the dimension indicating the size of the fluorine-containing compound is measured with a micrometer or vernier calipers.

[0056] When the fluorine-containing compound is in powder form, the average particle size can also be used as an index of size. When the fluorine-containing compound is in powder form, the average particle size may be 10 μm or more, preferably 30 μm or more, more preferably 100 μm or more, and even more preferably 200 μm or more, and is preferably 4000 μm or less, more preferably 2000 μm or less, and even more preferably 1000 μm or less. The average particle size of the fluorine-containing compound is measured in a dry state at a vacuum pressure of 20 mH2O using a laser diffraction / scattering particle size distribution analyzer manufactured by Nikkiso Co., Ltd., and is defined as being equal to the particle size corresponding to 50% of the integrated particle size distribution (volume basis).

[0057] The basic metal compound used in the production method of the present disclosure contains at least one selected from the group consisting of alkali metals and alkaline earth metals. The alkali metals include lithium, sodium, potassium, etc., and one or more of them can be used. The alkaline earth metals include magnesium, calcium, strontium, barium, etc., and one or more of them can be used. From the viewpoint of reactivity and suppression of corrosive gases, the basic metal compound preferably contains an alkaline earth metal, more preferably contains at least one selected from the group consisting of magnesium, calcium, and strontium, even more preferably contains at least one selected from the group consisting of magnesium and calcium, and even more preferably contains calcium.

[0058] From the viewpoint of reactivity and suppression of corrosive gases, the basic metal compound is preferably at least one selected from the group consisting of basic metal oxides, basic metal hydroxides, and basic metal carbonates.

[0059] The basic metal oxides include alkali metal oxides and alkaline earth metal oxides. The alkali metal oxides include lithium oxide, sodium oxide, potassium oxide, etc., and one or more of these can be used. The alkaline earth metal oxides include magnesium oxide, calcium oxide, strontium oxide, barium oxide, etc., and one or more of these can be used. As the basic metal oxide, from the viewpoint of reactivity and suppression of corrosive gases, alkaline earth metal oxides are preferred, at least one selected from the group consisting of magnesium oxide, calcium oxide, and strontium oxide is more preferred, at least one selected from the group consisting of magnesium oxide and calcium oxide is even more preferred, and calcium oxide (CaO) is even more preferred.

[0060] The basic metal hydroxides include alkali metal hydroxides and alkaline earth metal hydroxides. The alkali metal hydroxides include lithium hydroxide, sodium hydroxide, potassium hydroxide, etc., and one or more of them can be used. The alkaline earth metal hydroxides include magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, etc., and one or more of these can be used. As the basic metal hydroxide, from the viewpoints of reactivity and suppression of corrosive gases, alkaline earth metal hydroxides are preferred, at least one selected from the group consisting of magnesium hydroxide, calcium hydroxide, and strontium hydroxide is more preferred, at least one selected from the group consisting of magnesium hydroxide and calcium hydroxide is even more preferred, and calcium hydroxide (Ca(OH)2) is even more preferred.

[0061] The basic metal carbonates include alkali metal carbonates and alkaline earth metal carbonates. The alkali metal carbonates include lithium carbonate, sodium carbonate, potassium carbonate, etc., and one or more of them can be used. The alkaline earth metal carbonates include magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, etc., and one or more of these can be used. As the basic metal carbonate, from the viewpoints of reactivity and suppression of corrosive gases, alkaline earth metal carbonates are preferred, at least one selected from the group consisting of magnesium carbonate, calcium carbonate, and strontium carbonate is more preferred, at least one selected from the group consisting of magnesium carbonate and calcium carbonate is even more preferred, and calcium carbonate (CaCO3) is even more preferred.

[0062] As the basic metal compound, from the viewpoints of reactivity and suppression of corrosive gases, at least one selected from the group consisting of basic metal carbonates and basic metal hydroxides is preferred, basic metal carbonates are more preferred, and calcium carbonate is even more preferred. From the same viewpoint, the basic metal compound is preferably at least one selected from the group consisting of calcium carbonate, calcium oxide, calcium hydroxide, magnesium oxide, and magnesium hydroxide, more preferably at least one selected from the group consisting of calcium carbonate, calcium oxide, and magnesium hydroxide, and similarly, at least one selected from the group consisting of calcium carbonate, calcium hydroxide, and magnesium hydroxide is also preferred.

[0063] The mixing ratio of the basic metal compound in the mechanochemical treatment is preferably 0.1 equivalents or more, more preferably 0.5 equivalents or more, even more preferably 1 equivalent or more, even more preferably 1.5 equivalents or more, and particularly preferably 2 equivalents or more, relative to 1 equivalent (molar equivalent) of the fluorine-containing compound, and is preferably 10 equivalents or less, more preferably 8 equivalents or less, even more preferably 5 equivalents or less, even more preferably 4 equivalents or less, and particularly preferably 3 equivalents or less. When the fluorine-containing compound is a fluorine-containing polymer, the equivalent weight is calculated based on the monomers constituting the fluorine-containing polymer.

[0064] The mechanochemical treatment is a treatment method in which mechanical energy is applied to a reactant (preferably a solid reactant) by methods such as shearing, compression, stretching, grinding, friction, kneading, mixing, dispersing, crushing, and shaking, thereby activating the reactant and imparting structural change, phase transition, reactivity, adsorption, catalytic activity, and the like. The mechanochemical treatment method is not particularly limited, and examples thereof include a compressive shear treatment method, an impact treatment method, and a mixed shear friction method, with the impact treatment method being preferred.

[0065] The mechanochemical treatment is usually carried out using a grinding medium. The grinding medium is preferably not connected to the reaction vessel. The grinding medium may be used in combination with a member connected to the reaction vessel, such as a stirring member.

[0066] The shape of the grinding medium is not particularly limited, and may be spherical, ellipsoidal, cylindrical, cylindrical, bale-shaped, tea canister-shaped, etc., but from the viewpoint of reaction efficiency, it is preferably spherical, ellipsoidal, or cylindrical, more preferably spherical or ellipsoidal, and even more preferably spherical.

[0067] From the viewpoint of reaction efficiency, the grinding medium may have a length of at least one of the three dimensions that represent the size of the grinding medium of 1 mm or more, preferably 5 mm or more, and preferably 100 mm or less, more preferably 70 mm or less, even more preferably 50 mm or less, and even more preferably 40 mm or less. Of the three dimensions that represent the size of the grinding medium, it is preferable that the length of the shortest dimension be within the above range. Furthermore, it is more preferable that at least two of the three dimensions that represent the size of the grinding media are within the above range, and it is even more preferable that the three-dimensional length is within the above range. When the grinding media are spherical, it is preferable that the diameter is within the above range. By using grinding media having the above-mentioned sizes, the energy in the mechanochemical treatment can be further increased, and the reaction efficiency can be further improved.

[0068] The material of the grinding media is not particularly limited, and examples thereof include steels such as carbon steel, stainless steel, and chromium steel, zirconia, tungsten carbide, agate, silicon nitride, alumina, and polyamide, and one or more of these can be used. Among these, steels and zirconia are preferred, steels are more preferred, and carbon steel and stainless steel are even more preferred.

[0069] The material of the reaction vessel used in the mechanochemical treatment is not particularly limited, and examples include steels such as carbon steel, stainless steel, and chromium steel, zirconia, tungsten carbide, agate, silicon nitride, alumina, and polyamide, and one or more of these can be used. Among these, steels and zirconia are preferred, steels are more preferred, and carbon steel and stainless steel are even more preferred. The material of the reaction vessel may be the same as or different from that of the grinding medium.

[0070] From the viewpoint of reaction efficiency, the filling rate of the grinding media relative to the internal volume of the reaction vessel is preferably 50% by volume or more, more preferably 60% by volume or more, and is preferably 90% by volume or less, more preferably 85% by volume or less, and even more preferably 83% by volume or less.

[0071] From the viewpoint of reaction efficiency, the ratio of the material to the internal volume of the reaction vessel is preferably 0.3% by volume or more, more preferably 0.5% by volume or more, and even more preferably 1% by volume or more, and is preferably 20% by volume or less, more preferably 10% by volume or less, and even more preferably 6% by volume or less. The proportion of the material to be treated is the total proportion of all raw materials to be mechanochemically treated, such as the fluorine-containing compound and the basic metal compound.

[0072] The mechanochemical treatment is preferably carried out with an applied energy of 0.1 J / s / g or more, more preferably 0.3 J / s / g or more, even more preferably 0.5 J / s / g or more, even more preferably 1.0 J / s / g or more, even more preferably 2.0 J / s / g or more, particularly preferably 2.5 J / s / g or more, and preferably 30 J / s / g or less, more preferably 15 J / s / g or less, even more preferably 10 J / s / g or less, and even more preferably 5.0 J / s / g or less. By applying energy within the above range, it is possible to further increase the reaction efficiency and further suppress the generation of corrosive gases during heat treatment. The energy to be applied is not particularly limited as long as it is mechanical energy, but collision energy is particularly preferred.

[0073] The energy is energy per unit mass, and in the case of collision energy, for example, it is calculated using simulation software according to the following formula, based on the method described in AIChE Journal, Vol. 52, No. 10, 2006, pp. 3421-3426. The simulation software is not limited as long as it can perform calculations based on the above method, and for example, KIK DEM manufactured by Tohoku University or UX-DEM manufactured by JX Metals can be used.

number

[0074] The mechanochemical treatment is preferably carried out with an integrated energy of 3,000 J / g or more, more preferably 3,800 J / g or more, even more preferably 5,000 J / g or more, even more preferably 10,000 J / g or more, and preferably 400,000 J / g or less, more preferably 150,000 J / g or less, even more preferably 100,000 J / g or less, even more preferably 90,000 J / g or less. By adding an integrated energy within the above range, it is possible to further increase the reaction efficiency and further suppress the generation of corrosive gases during heat treatment. The energy to be applied is not particularly limited as long as it is mechanical energy, but collision energy is particularly preferred.

[0075] The integrated energy is the integrated energy per unit mass, and is a value obtained by multiplying the above-mentioned energy by the processing time of the mechanochemical treatment.

[0076] The apparatus for performing the mechanochemical treatment is not particularly limited as long as it is an apparatus capable of applying mechanical energy by the above-mentioned method, and known pulverizers and mixers can be used. For example, pulverizers such as ball mills, rod mills, jet mills, rotary mills, vibration mills, SAG mills, and planetary mills; grinders such as rotary stone mills and crushers; (horizontal axis rotation) container rotation type mixers such as horizontal cylindrical, V-type, double cone, square cube, S-type, and continuous V-type; (baffle blade equipped) container rotation type mixers such as horizontal cylindrical, V-type, double cone, and ball mills; (rotation vibration) container rotation type mixers such as rocking and cross rotary types; ribbon type, paddle type, single-shaft rotor type, and bag mill type. (horizontal axis rotation) fixed vessel type mixers; (vertical axis rotation) fixed vessel type mixers such as ribbon type, screw type, planetary type, turbine type, high speed fluid type, rotating disk type and Mahler type; (vibration) fixed vessel type mixers such as vibration mill type and sieve; (fluidization) fluid motion type mixers such as heterogeneous fluidized bed, swirling fluidized bed, type with riser and Jot pump type; (gravity) fluid motion type mixers such as gravity type and static mixer; and kneaders such as twin-screw kneaders, single-screw kneaders, mixers, roll mills, etc.

[0077] As the apparatus for carrying out the mechanochemical treatment, a rotary mill, a vibration mill, or a planetary mill is preferred, with a vibration mill or a planetary mill being more preferred. In addition, from the viewpoint of ease of industrialization, a rotary mill or a vibration mill is preferred, with a vibration mill being more preferred.

[0078] The mechanochemical treatment can be carried out using a planetary mill, but is also preferably carried out without a planetary mill. While a planetary mill is a device capable of applying high energy, it also generates a large amount of wear debris from the device (see, for example, J.Soc.Powder Technol.,Japan,44,186-190(2007)[https: / / www.jstage.jst.go.jp / article / sptj1978 / 44 / 3 / 44_3_186 / _pdf / -char / ja]). The inclusion of wear debris can interfere with the use of the reaction product. The production method of the present disclosure can react a fluorine-containing compound under conditions that are less likely to generate wear debris from the device. Furthermore, methods using general-purpose devices such as ball mills and vibration mills, rather than planetary mills, also have the advantage of being easily industrialized.

[0079] The temperature of the mechanochemical treatment is preferably 5°C or higher, more preferably 10°C or higher, even more preferably 15°C or higher, even more preferably 20°C or higher, and is preferably less than 300°C, more preferably 250°C or lower, even more preferably 200°C or lower, even more preferably 160°C or lower.

[0080] In particular, when the fluorine-containing compound is a fluorine-containing polymer compound that does not contain hydrogen, the reaction is accelerated by heating, so it is preferable to carry out the reaction at room temperature (25° C.) or above.

[0081] The time for the mechanochemical treatment can be determined depending on the equipment used, the amount of material to be treated, etc., but may be, for example, 0.1 hours or more, 0.5 hours or more, 1 hour or more, or 100 hours or less, 50 hours or less, 30 hours or less, 20 hours or less, or 10 hours or less.

[0082] The mechanochemical treatment may be carried out in any atmosphere, for example, in air, in an inert gas, in vacuum, etc. From the viewpoint of low cost, it is preferably carried out in air.

[0083] The mechanochemical treatment is preferably carried out in a dry manner, which means that the amount of liquid in the reaction system is 5% by mass or less, preferably 1% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.01% by mass or less.

[0084] The mechanochemical treatment provides a composition containing the fluorine-containing compound and the basic metal compound. When the basic metal compound is at least one selected from the group consisting of the basic metal carbonates and the basic metal hydroxides, the composition obtained in step (1) can be used as the composition of the present disclosure described below.

[0085] The content of the fluorine-containing compound in the composition obtained in step (1) is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, and is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 25% by mass or less, based on the composition. The content of the fluorine-containing compound is measured by washing the composition with hydrochloric acid to remove components other than the fluorine-containing compound, and then by a gravimetric method.

[0086] The content of the basic metal compound in the composition is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and even more preferably 70% by mass or more, and is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, relative to the composition. The content of the basic metal compound is determined by measuring the composition by XRD, and if no metal fluoride is present, the composition is washed with hydrochloric acid and the content is determined from the mass loss. If a metal fluoride is present, the ratio of the basic metal compound to the metal fluoride is determined from the chart obtained by XRD using the RIR method (reference intensity ratio method), and the product is then washed with hydrochloric acid, and the content is determined from the mass loss and the ratio of the basic metal compound to the metal fluoride before washing. The RIR method can be performed by performing analysis with an analyzer attached to the XRD measurement device.

[0087] The composition may or may not contain a metal fluoride containing at least one selected from the group consisting of alkali metals and alkaline earth metals. The content of the metal fluoride in the composition may be 30% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, or 5% by mass or less, relative to the composition. The content of the metal fluoride may be 0% by mass, or may be 0.5% by mass or more, or may be 1% by mass or more. The content of the metal fluoride can be measured by the RIR method using X-ray diffraction (XRD).

[0088] In step (2), the composition obtained in step (1) is heat-treated to obtain a metal fluoride containing at least one selected from the group consisting of alkali metals and alkaline earth metals.

[0089] From the viewpoint of reactivity, the temperature of the heat treatment is preferably 300°C or higher, more preferably 350°C or higher, even more preferably 400°C or higher, and even more preferably 450°C or higher; from the viewpoint of production costs, etc., the temperature is preferably 800°C or lower, more preferably 700°C or lower, even more preferably 600°C or lower, and even more preferably 550°C or lower.

[0090] The heat treatment may be carried out under pressure. In this case, the pressure is not particularly limited, but is preferably 30 MPa or less, more preferably 20 MPa or less, and even more preferably 10 MPa or less. The lower limit is not particularly limited, and may be the lowest pressure that can be set by the apparatus. In the manufacturing method of the present disclosure, heat treatment can be performed under the above-mentioned relatively low pressure conditions, thereby reducing production costs.

[0091] The time for the heat treatment can be determined depending on the equipment used, the amount of material to be treated, etc., and may be, for example, 10 minutes or more, 0.5 hours or more, 1 hour or more, 3 hours or more, or 100 hours or less, 50 hours or less, 30 hours or less, or 10 hours or less.

[0092] The heat treatment may be carried out in any atmosphere, for example, in air, in an inert gas, in vacuum, etc. From the viewpoint of low cost, it is preferably carried out in air.

[0093] The heat treatment can be carried out using known equipment, such as a hot air circulation device, a vacuum heat treatment device, a box-type electric furnace, a single-screw extruder, a twin-screw extruder, a kiln furnace, a microwave device, or an infrared heater.

[0094] By the heat treatment, a metal fluoride containing at least one selected from the group consisting of alkali metals and alkaline earth metals is obtained. The alkali metals and alkaline earth metals include the same as those contained in the basic metal compounds, and the preferred forms are also the same. The metal fluoride may be at least one selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides, is preferably an alkaline earth metal fluoride, is more preferably at least one selected from the group consisting of magnesium fluoride and calcium fluoride, and is further preferably calcium fluoride (CaF).

[0095] The production method of the present disclosure also preferably includes a step of purifying the crude product obtained in the above step (2) to recover the metal fluoride. The purification method is not particularly limited, and any known method can be used.

[0096] The production method of the present disclosure can be used not only for producing metal fluorides but also for decomposing (defluorinating) fluorine-containing compounds.

[0097] The present disclosure also relates to a composition comprising a fluorine-containing compound and a basic metal compound containing at least one selected from the group consisting of alkali metals and alkaline earth metals, wherein the amount of fluoride ions generated when heated at 600°C for 1 hour is 15 mass% or less relative to the fluorine-containing compound, and the basic metal compound is at least one selected from the group consisting of basic metal carbonates and basic metal hydroxides.

[0098] The composition of the present disclosure has the above-described configuration, and therefore can suppress the generation of corrosive gases such as hydrogen fluoride during heat treatment, and can produce a metal fluoride after heat treatment. Therefore, the composition can be used for various purposes, such as the production of metal fluorides, using general-purpose equipment without using equipment with high corrosion resistance.

[0099] Examples of the fluorine-containing compound in the composition of the present disclosure include the same fluorine-containing compounds as those that can be used in the production method of the present disclosure, and the preferred forms are also the same.

[0100] The content of the fluorine-containing compound in the composition of the present disclosure is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, and is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 25% by mass or less, relative to the composition. The content of the fluorine-containing compound is measured by washing the composition with hydrochloric acid to remove components other than the fluorine-containing compound, and then by a gravimetric method.

[0101] In the composition of the present disclosure, the maximum length of the fluorine-containing compound is preferably less than 2 mm, more preferably 1.5 mm or less, even more preferably 1 mm or less, and even more preferably 0.5 mm or less, and may be 0.0001 mm or more, or may be 0.001 mm or more. The composition in which the maximum length of the fluorine-containing compound falls within the above range can be obtained by mechanochemical treatment. The maximum length is determined by exposing a cross section of a secondary particle of the composition, identifying a region where fluorine element (fluorine-containing compound) is present by SEM / EDX, and measuring the maximum length of the region where fluorine element is continuously present (region occupied by fluorine-containing compound) from the SEM image. The cross section can be obtained by, for example, embedding the composition in a thermosetting resin or the like, and cutting out the embedded composition using a microtome or the like.

[0102] Examples of the basic metal compound in the composition of the present disclosure include the same basic metal carbonates and basic metal hydroxides as the basic metal compounds that can be used in the production method of the present disclosure, and the preferred forms are also the same.

[0103] The content of the basic metal compound in the composition of the present disclosure is preferably 1% by mass or more, more preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, and even more preferably 70% by mass or more, and is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, relative to the composition. The content of the basic metal compound is determined by measuring the composition by XRD, and if no metal fluoride is present, the composition is washed with hydrochloric acid and the content is determined from the mass loss. If a metal fluoride is present, the ratio of the basic metal compound to the metal fluoride is determined from the chart obtained by XRD using the RIR method (reference intensity ratio method), and the product is then washed with hydrochloric acid, and the content is determined from the mass loss and the ratio of the basic metal compound to the metal fluoride before washing. The RIR method can be performed by performing analysis with an analyzer attached to the XRD measurement device.

[0104] The composition of the present disclosure may or may not contain a metal fluoride containing at least one selected from the group consisting of alkali metals and alkaline earth metals. The metal fluoride may be at least one selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides, preferably an alkaline earth metal fluoride, more preferably at least one selected from the group consisting of magnesium fluoride and calcium fluoride, and even more preferably calcium fluoride (CaF). The content of the metal fluoride in the composition may be 50% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, relative to the composition. The content of the metal fluoride may be 0% by mass, or may be 0.5% by mass or more, or may be 1% by mass or more. The content of the metal fluoride can be measured by the RIR method using X-ray diffraction (XRD).

[0105] The composition of the present disclosure generates fluoride ions in an amount of 15% by mass or less, based on the amount of the fluorine-containing compound, when heated at 600°C for 1 hour. The amount is preferably 13% by mass or less, more preferably 11% by mass or less, even more preferably 10% by mass or less, even more preferably 9% by mass or less, still more preferably 6% by mass or less, and particularly preferably 3% by mass or less, and may be 0% by mass or more, 0.01% by mass or more, or 0.1% by mass or more. By ensuring that the amount of fluoride ions generated is within the above range, it is possible to sufficiently suppress the generation of corrosive gases during heat treatment. A composition having a fluoride ion generation amount within the above range can be obtained by mechanochemical treatment.

[0106] The amount of generated fluoride ions is measured by the following method. The sample is heated by placing the quartz tube containing the sample in a furnace heated under the following conditions, and the evolved gas is collected and dissolved in 20 mL of alkaline collection liquid. The collection liquid containing the dissolved evolved gas is analyzed by ion chromatography under the following conditions to quantify the amount of fluoride ions. (Heating conditions) Sample: Approximately 10 mg Heating temperature: 600℃ Pressure: atmospheric pressure Atmosphere: Air Flow rate: 50mL / min Collection time: 1 hour (Ion chromatography conditions) Apparatus: Thermo Fisher Scientific ICS-5000 + Separation column: 2mmφ×250mm IonPac AS30 Eluent: potassium hydroxide / gradient Sample injection volume: 10 μL Detector: Electrical conductivity meter

[0107] In the composition of the present disclosure, the fluorine component is preferably uniformly dispersed. The state of dispersion of the fluorine component can be confirmed, for example, by cutting a block of the composition and observing the cross section by mapping fluorine atoms using SEM / EDX.

[0108] When the composition of the present disclosure is subjected to thermogravimetric analysis at a heating rate of 10°C / min, the ratio of the mass loss at 500°C to the mass loss at 600°C is preferably 25% or more, more preferably 30% or more, even more preferably 50% or more, even more preferably 70% or more, even more preferably 90% or more, and particularly preferably 95% or more, and may be less than 100%, 99.99% or less, or 99.9% or less. When the ratio of the mass loss at 500°C to the mass loss at 600°C is within the above range, the generation of corrosive gases during heat treatment can be further suppressed. A composition having a ratio of the mass loss at 500°C to the mass loss at 600°C within the above range can be obtained by mechanochemical treatment.

[0109] The ratio of the mass loss at 500°C to the mass loss at 600°C is calculated by precisely weighing approximately 10 mg of sample, placing it in a dedicated aluminum pan, and using a TG-DTA (differential thermal and thermogravimetric simultaneous analyzer) to raise the temperature from 25°C to 600°C at a rate of 10°C / min in an air atmosphere, measuring the mass loss at 500°C and 600°C (mass loss from 25°C), and then calculating using the following formula. Ratio of mass loss at 500°C to mass loss at 600°C = mass loss at 500°C / mass loss at 600°C × 100

[0110] The composition of the present disclosure preferably has a 1% decomposition temperature of 450°C or less, more preferably 400°C or less, even more preferably 350°C or less, even more preferably 335°C or less, and may be 300°C or more. By ensuring that the 1% decomposition temperature is within the above range, the generation of corrosive gases during heat treatment can be further suppressed. A composition having a 1% decomposition temperature within the above range can be obtained by mechanochemical treatment.

[0111] The 1% decomposition temperature is determined by precisely weighing approximately 10 mg of sample, placing it in a dedicated aluminum pan, and using a TG / DTA (differential thermal / thermogravimetric simultaneous analysis device) to raise the temperature from 25°C to 600°C at a rate of 10°C / min in an air atmosphere. The temperature corresponds to the point at which the mass has decreased by 1% by mass from the mass at 25°C.

[0112] The composition of the present disclosure preferably contains secondary particles in which both fluorine and at least one metal selected from the group consisting of alkali metals and alkaline earth metals are detected when observed by SEM / EDX, thereby further suppressing the generation of corrosive gases during heat treatment. The composition containing the specific secondary particles can be obtained by mechanochemical treatment. The specific secondary particles are considered to be a composite of a fluorine-containing compound and a basic metal compound, and cannot be obtained by simply mixing the fluorine-containing compound and the basic metal compound.

[0113] The composition of the present disclosure can be suitably produced, for example, by step (1) of the production method of the present disclosure described above.

[0114] The composition of the present disclosure can be suitably used for producing metal fluorides because it generates a metal fluoride containing at least one selected from the group consisting of alkali metals and alkaline earth metals by heat treatment. It can also be suitably used as a foaming inhibitor in steel manufacturing, a raw material for hydrogen fluoride, etc. Among these, it can be suitably used as a foaming inhibitor.

[0115] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims. [Example]

[0116] The present disclosure will now be described in more detail with reference to examples, but the present disclosure is not limited to these examples.

[0117] Each value was determined by the following method.

[0118] <Size of fluorine-containing compounds> (flakes) The thickness (μm) of the fluorine-containing compound was measured using a micrometer on 20 or more flakes, and the average value was used as the thickness. The long and short sides (mm) of the fluorine-containing compound were measured using images taken with a Keyence VHX5000 video microscope on 90 or more flakes, and the average values ​​were used as the long and short sides. (powder) Measurements were carried out dry at a vacuum pressure of 20 mH2O using a laser diffraction / scattering particle size distribution analyzer manufactured by Nikkiso Co., Ltd., and the particle size was determined to be equal to the particle diameter corresponding to 50% of the integrated particle size distribution (volume basis).

[0119] <Collision energy, cumulative collision energy> The collision energy was calculated from the following formula using simulation software KIK DEM (manufactured by Tohoku University) based on the method described in AIChE Journal, Vol. 52, No. 10, 2006, pp. 3421-3426.

number

[0120] <Maximum length of fluorine-containing compound in composition obtained by mechanochemical treatment> After cross-sectioning the secondary particles of the composition, the region where fluorine element (fluorine-containing compound) is present is identified by SEM / EDX, and the maximum length of the region where fluorine element is continuously present (region occupied by fluorine-containing compound) is measured from the SEM image to determine the maximum length. The cross section was obtained by embedding the composition in a thermosetting resin or the like and cutting out the embedded composition using a microtome or the like.

[0121] <Content of Fluorine-Containing Compound in Composition Obtained by Mechanochemical Treatment> The composition was washed with hydrochloric acid to remove components other than the fluorine-containing compound, and the content of the fluorine-containing compound was measured by a gravimetric method.

[0122] <Content of basic metal compound in composition obtained by mechanochemical treatment> The composition was measured by XRD, and if no metal fluoride was present, the composition was washed with hydrochloric acid and the mass was determined from the loss. When metal fluorides were present, the ratio of basic metal compounds to metal fluorides was determined from the chart obtained by XRD using the RIR method (reference intensity ratio method), and the product was then washed with hydrochloric acid, and the mass was determined from the mass loss and the ratio of basic metal compounds to metal fluorides before washing. The RIR method was performed by performing analysis on an XRD measurement device with an attached analyzer.

[0123] <Ratio of mass loss at 500°C to mass loss at 600°C> The composition obtained by the mechanochemical treatment was used as the sample. Approximately 10 mg of sample was weighed out and placed in a special aluminum pan. Using a TG-DTA (differential thermal and thermogravimetric simultaneous analysis device), the temperature was raised from 25°C to 600°C at a rate of 10°C / min in an air atmosphere, and the mass loss at 500°C and 600°C (mass loss from 25°C) was measured and calculated using the following formula. Ratio of mass loss at 500°C to mass loss at 600°C = mass loss at 500°C / mass loss at 600°C × 100

[0124] <1% decomposition temperature> The composition obtained by the mechanochemical treatment was used as the sample. Approximately 10 mg of sample was weighed out and placed in a special aluminum pan. Using a TG-DTA (differential thermal and thermogravimetric simultaneous analysis device), the sample was heated in an air atmosphere from 25°C to 600°C at a rate of 10°C / min, until the temperature reached the point where the mass had decreased by 1% from the mass at 25°C.

[0125] <Fluoride ion generation amount> The composition obtained by the mechanochemical treatment was used as the sample. The sample was heated by placing the quartz tube containing the sample in a furnace heated under the following conditions, and the evolved gas was collected and dissolved in 20 mL of alkaline collection liquid. The collection liquid containing the dissolved evolved gas was analyzed by ion chromatography under the following conditions to quantify the amount of fluoride ions. (Heating conditions) Sample: Approximately 10 mg Heating temperature: 600℃ Pressure: atmospheric pressure Atmosphere: Air Flow rate: 50mL / min Collection time: 1 hour (Ion chromatography conditions) Apparatus: Thermo Fisher Scientific ICS-5000 + Separation column: 2mmφ×250mm IonPac AS30 Eluent: potassium hydroxide / gradient Sample injection volume: 10 μL Detector: Electrical conductivity meter

[0126] In each experimental example, the following materials (all solid at 25° C.) were used. <Fluorine-containing compounds> PTFE (1): Powder of PTFE M18 manufactured by Daikin Industries, Ltd. was compression molded under conditions of 30 MPa for 1 minute and then baked at 370°C for 3 hours to obtain a molded product. The molded product obtained was then cut and crushed into flakes with an average thickness of 129 μm, an average long side of 2.4 mm, and an average short side of 0.9 mm. PTFE (2): PTFE (1) is further crushed in an impact crusher to produce powdered secondary particles with a D50 of 208 μm. PFA: Daikin Industries AP-201 Fluorine rubber: A cross-linked sheet obtained by peroxide vulcanization of Daikin Industries' Daiel G801, which is then frozen and crushed. <Basic metal compounds> CaCO3 (basic metal carbonate): Calcium carbonate (special grade reagent) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. CaO (basic metal oxide): Prepared by heating calcium hydroxide (special grade reagent) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. at 900°C for 2 hours, and stored in a desiccator until it returned to room temperature before use. MgO (basic metal oxide): Magnesium oxide manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Mg(OH)2 (basic metal hydroxide): Magnesium hydroxide manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0127] Examples 1, 2, 5 to 7, 9, 10 to 13 The raw materials (fluorine-containing compound, basic metal compound) shown in Table 1 were weighed. The raw materials and zirconia balls as grinding media were placed in the pot of a planetary mill. A lid was attached to the pot, and the pot was placed in the planetary mill body and started to rotate. Mechanochemical treatment was carried out for a predetermined time, yielding a composition containing a fluorine-containing compound and a basic metal compound. The physical properties of the obtained composition were measured. The results are shown in Table 1. The planetary mill used for the mechanochemical treatment is as follows: Equipment: Fritsch Pulverisette planetary ball mill P-7 Grinding tube: Zirconia pot (volume 45 mL, diameter 40 mm) Grinding media: zirconia balls (φ15 mm), 7 pieces, filling rate 80% by volume

[0128] Approximately 10 mg of the composition obtained above was weighed out and placed in a dedicated aluminum pan. Heat treatment was carried out using a TG-DTA (differential thermal and thermogravimetric simultaneous analyzer, Hitachi High-Tech Science Corporation, TG / DTA7200) in an air atmosphere by increasing the temperature from 25°C to 600°C at a rate of 10°C / min. The resulting residue was measured by XRD (Rigaku Corporation, Smartlab). Peaks were detected at positions that could be identified as CaF2, confirming the generation of CaF2 in Examples 1, 2, 5 to 7, and 9. In Example 10, a peak was detected at a position that could be identified as MgF2, confirming the generation of MgF2.

[0129] Furthermore, for Examples 1, 2, and 5 to 7, the compositions obtained by the mechanochemical treatment were used to measure the amount of fluoride ions generated according to the method for measuring the amount of fluoride ions generated described above. The results are shown in Table 1.

[0130] Examples 3, 4, and 8 The raw materials (fluorine-containing compound, basic metal compound) shown in Table 1 were weighed. Approximately half of the steel balls used as grinding media were placed in the pot of a vibration mill, followed by approximately half of the raw materials. The remaining steel balls were then placed in the pot, followed by the remaining raw materials. A lid was attached to the pot, and the pot was placed in the vibration mill body, and vibration was initiated. Mechanochemical treatment was carried out for a predetermined time, yielding a composition containing a fluorine-containing compound and a basic metal compound. The physical properties of the obtained composition were measured. The results are shown in Table 1. The vibrating mill used in the mechanochemical treatment was as follows: Equipment: MB1 vibration mill manufactured by Chuo Kakoki Co., Ltd. Grinding tube: SUS pot (internal volume 3.6 L, φ145 x 225 mm) Grinding media: Carbon steel balls (φ35 mm or φ20 mm), 80% filling rate, or SUS rods (φ25 mm, length 215 mm), 60% filling rate by volume Frequency: 1200 rpm Total amplitude: 8mm Water Cooling: None

[0131] The composition obtained above was used to measure the amount of fluoride ions generated in accordance with the method for measuring the amount of fluoride ions generated described above. The results are shown in Table 1. Furthermore, after the mechanochemical treatment, the composition was heated from room temperature to 600°C at 10°C / min, and the residue after heating was measured using XRD. A peak was detected at a position that could be identified as CaF2, confirming the generation of CaF2.

[0132] Comparative Example 1 The experiment was carried out in the same manner as in Example 1, except that the raw materials (fluorine-containing compound, basic metal compound) shown in Table 1 were weighed, placed in a polyethylene bag without mechanochemical treatment, and then mixed by shaking for 3 minutes. The results are shown in Table 1.

[0133] Comparative Example 2 The physical properties of PTFE (1) alone were measured, and the results are shown in Table 1.

[0134] [Table 1]

[0135] From the results of each example, it was found that the production method and composition of the present disclosure generate a small amount of fluoride ions during heat treatment, and therefore can suppress the generation of corrosive gas (HF).

Claims

1. A method for producing a metal fluoride, comprising: (1) a step of mechanochemically treating a fluorine-containing compound and a basic metal compound containing at least one selected from the group consisting of alkali metals and alkaline earth metals to obtain a composition containing the fluorine-containing compound and the basic metal compound; and (2) a step of heat-treating the composition to obtain a metal fluoride containing at least one selected from the group consisting of alkali metals and alkaline earth metals.

2. 2. The method according to claim 1, wherein the energy in the mechanochemical treatment is 0.1 J / s / g or more.

3. 3. The method according to claim 1, wherein the energy in the mechanochemical treatment is 0.5 to 10 J / s / g.

4. 3. The method according to claim 1, wherein the cumulative energy in the mechanochemical treatment is 3,000 J / g or more.

5. 3. The method according to claim 1, wherein the cumulative energy in the mechanochemical treatment is 3,800 to 400,000 J / g.

6. 3. The method according to claim 1, wherein the mechanochemical treatment is carried out using a planetary mill or a vibrating mill.

7. 3. The method according to claim 1, wherein the heat treatment is carried out at a temperature of 300° C. or higher.

8. 3. The method according to claim 1, wherein the temperature of the heat treatment is 300 to 800°C.

9. 3. The method according to claim 1, wherein the heat treatment time is from 10 minutes to 100 hours.

10. 3. The method according to claim 1, wherein the basic metal compound is at least one selected from the group consisting of basic metal oxides, basic metal hydroxides, and basic metal carbonates.

11. 3. The method according to claim 1, wherein the basic metal compound is a basic metal compound containing magnesium or calcium.

12. 3. The method according to claim 1, wherein the basic metal compound is at least one selected from the group consisting of calcium carbonate, calcium oxide, calcium hydroxide, magnesium oxide and magnesium hydroxide.

13. 3. The method according to claim 1, wherein the fluorine-containing compound is a fluorine-containing polymer.

14. 3. The production method according to claim 1 or 2, wherein the fluorine-containing compound is at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, polydifluoroethylene, ethylene / tetrafluoroethylene copolymer, and fluororubber.

15. 3. The method according to claim 1, wherein the mixing ratio of the basic metal compound is 1 to 10 equivalents per equivalent of the fluorine-containing compound.

16. 3. The method according to claim 1, wherein the mixing ratio of the basic metal compound is 1 to 4 equivalents per equivalent of the fluorine-containing compound.

17. A composition comprising a fluorine-containing compound and a basic metal compound containing at least one selected from the group consisting of alkali metals and alkaline earth metals, wherein the amount of fluoride ions generated when heated at 600°C for 1 hour is 15 mass% or less relative to the fluorine-containing compound, and the basic metal compound is at least one selected from the group consisting of basic metal carbonates and basic metal hydroxides.

18. The composition according to claim 17, wherein the content of the fluorine-containing compound is 10% by mass or more.

19. The composition according to claim 17 or 18, wherein the content of the fluorine-containing compound is 10 to 40% by mass.

20. 19. The composition according to claim 17, wherein the content of the basic metal compound is 65 to 90 mass %.

21. 19. The composition according to claim 17 or 18, wherein the ratio of the mass loss at 500°C to the mass loss at 600°C is 25% or more when subjected to thermogravimetric analysis at a heating rate of 10°C / min.

22. The composition according to claim 17 or 18, wherein the fluorine-containing compound is a fluorine-containing polymer.

23. The composition according to claim 17 or 18, wherein the fluorine-containing compound is at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, polydifluoroethylene, ethylene / tetrafluoroethylene copolymer, and fluororubber.

24. 19. The composition according to claim 17, wherein the basic metal compound is at least one selected from the group consisting of calcium carbonate, calcium oxide, calcium hydroxide, magnesium oxide, and magnesium hydroxide.

25. The composition according to claim 17 or 18, which is used as a foaming inhibitor.

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