Metal carbide and method for producing metal carbide

Abstract

To provide a metal carbide capable of stably supplying a raw material of a bioplastic at a relatively low cost, and to provide a method for producing the metal carbide.SOLUTION: According to an aspect of the present invention, there is provided a metal-carbide having a biomass degree of 0.01% or more and 100% or less, the biomass degree being measured by a 14C isotopic measurement method defined in ASTMD6866.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to metal carbides and methods for producing metal carbides. [Background technology]

[0002] In recent years, there has been an increasing demand for bioplastics in order to reduce the burden on the environment. As a bioplastic, biopolyethylene has been put on the market and is expected to contribute to reducing carbon dioxide emissions (see Patent Document 1). This biopolyethylene is produced from ethylene obtained using bionaphtha and the like.

[0003] However, bionaphtha is produced from waste materials and residues such as used cooking oil, and its supply is limited. Research is also underway to obtain bioethanol from wood, a non-edible biomass, and to produce ethylene from this bioethanol. However, in both of the above cases, the raw materials are denatured by fermentation, making it difficult to significantly reduce costs. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-511634 A Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above circumstances, the present invention provides a metal carbide that can provide a relatively inexpensive and stable supply of raw materials for bioplastics, and a method for producing the metal carbide. [Means for solving the problem]

[0006] According to one aspect of the present invention, a metal carbide as defined in ASTM D6866 is14 There is provided a metal carbide having a biomass content of 0.01% or more and 100% or less as measured by C isotope measurement.

[0007] According to this embodiment, raw materials for bioplastics can be supplied relatively cheaply and stably. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of metal carbide and a method for manufacturing the same will be described. Various features shown in the following embodiments can be combined with each other.

[0009] <Metal carbide> The metal carbide of this embodiment is defined in ASTM D6866. 14 The biomass ratio measured by C isotope measurement is approximately 0.01% to 100%. Metal carbides are compounds represented by the chemical formula MC or MC2 (M is a metal atom), and are used, for example, as a convenient source of acetylene. From acetylene, industrially important compounds (e.g., 2-chloro-1,3-butadiene: chloroprene monomer) that are used as raw materials for various plastics can be obtained. Therefore, metal carbide having the above-mentioned biomass content can provide a relatively inexpensive and stable supply of raw materials for bioplastics.

[0010] Here, the biomass ratio means the ratio of carbon atoms derived from biomass contained in the metal carbide. This biomass ratio is determined by the radioactive carbon ( 14 C) contained in the metal carbide. In this specification, the biomass degree is defined in ASTM D6866. 14Accelerator Mass Spectrometry (AMS), a type of C isotope measurement method, was used to measure the total carbon atoms contained in metal carbide. 14 It is determined by measuring the percentage of carbon (percent modern carbon: pMC) and calculating the percentage (content) of carbon atoms derived from biomass.

[0011] The biomass degree should be approximately 0.01% or more and 100% or less, preferably approximately 0.1% or more and 80% or less, and more preferably approximately 1% or more and 60% or less. If the biomass degree is set to the upper limit or less, the raw material for bioplastics can be supplied more cheaply. On the other hand, if the biomass degree is set to the lower limit or more, it will be easier to contribute to the realization of a carbon-recycling society.

[0012] Metal carbides are preferably used to produce acetylene. This is because acetylene (bioacetylene) can be used to produce industrially important compounds that serve as raw materials for various plastics (bioplastics). For example, ethylene can be produced by hydrogenating acetylene, acrylonitrile by reacting acetylene with hydrogen cyanide, vinyl chloride by reacting acetylene with hydrogen chloride, acrylic acid by reacting acetylene with carbon monoxide and water, monovinylacetylene by dimerization of acetylene, vinyl acetate by reacting acetylene with acetic acid, and acetaldehyde by reacting acetylene with water. Furthermore, acrylic acid can be reacted with alcohol to produce acrylic esters. Acetylene black can also be produced by thermal decomposition of acetylene.

[0013] Metal carbides (especially calcium carbide) are also preferably used to produce calcium nitrate. Calcium nitrate is mainly composed of calcium cyanamide and also contains calcium oxide. After exerting its pesticide effects (insecticidal, herbicidal, and fungicidal effects), calcium cyanamide decomposes into fertilizer components in the soil, leaving no residue and making it safe to use. In addition, calcium nitrate is less likely to run off from the soil and exhibits slow release, which allows for a reduction in the frequency and amount of fertilizer application. The use of calcium nitrate not only corrects the acidity of the soil, but also promotes the decomposition of organic matter, making it easier to create soil suitable for cultivation. Such calcium nitrate can be produced, for example, by absorbing and compounding nitrogen into the calcium carbide at high temperature.

[0014] The metal carbide reacts with pure water to generate acetylene, and the content of sulfur atoms in the metal carbide is preferably about 100 ppm or less, more preferably about 90 ppm or less, even more preferably about 80 ppm or less, particularly preferably about 50 ppm or less, and may be 0 ppm. The metal carbide reacts with pure water to generate acetylene, and the content of phosphorus atoms in the metal carbide is preferably about 1 ppm or more and 320 ppm or less, more preferably about 5 ppm or more and 250 ppm or less, even more preferably about 10 ppm or more and 200 ppm or less, and particularly preferably about 20 ppm or more and 180 ppm or less. The metal carbide reacts with pure water to generate acetylene, and the ash content in the metal carbide is preferably about 10% by mass or less, more preferably about 8% by mass or less, even more preferably about 5% by mass or less, particularly preferably about 3% by mass or less, and may be 0% by mass.

[0015] <Metal carbide manufacturing method> The above-mentioned metal carbide can be produced, for example, by the following method for producing metal carbide. The method for producing metal carbide according to the present embodiment includes a step of preparing a carbon source containing biomass and a metal source, and a step of heating the carbon source and the metal source in an electric furnace to obtain the metal carbide described above. Each step will be described below.

[0016] <<Preparation process>> First, a carbon source containing biomass and a metal source are prepared. Examples of biomass include plant-derived biomass, animal-derived biomass, etc. These waste materials may be used alone or in combination of two or more types. Examples of plant-derived biomass include felled trees, sawdust generated at sawmills, wood chips, and branches; agricultural crops such as corn, sugarcane, wheat, rice, soybeans, rapeseed, and sorghum; agricultural residues such as rice straw, wheat straw, corn stalks and leaves, coconut shells, and bagasse (sugarcane pomace); grasses (herbaceous plants) such as switchgrass and miscanthus; algae such as seaweed and microalgae; pulp; lignocelluloses such as lignin; fruit peels, seeds, and vegetable oils. Examples of biomass derived from animals include manure from livestock (such as cows, pigs, and chickens), livestock by-products such as bones or organs of livestock, and animal oils.

[0017] Note that biomass may be used after separation using a specific method. For example, lignocellulosic biomass may be prepared as biomass, and insoluble matter containing lignin (lignin-containing components) may be separated and recovered from this lignocellulosic biomass using a dilute sulfuric acid method or a concentrated sulfuric acid method. Biomass may be used as a carbon source as is, or the carbonized product obtained after carbonization may be used as a carbon source. The fixed carbon content in the carbon source can be adjusted, for example, by controlling the temperature (carbonization temperature) when carbonizing the biomass. Specifically, the fixed carbon (carbon atom) content in the carbon source is preferably about 85% by mass or more, more preferably about 90% by mass or more, and even more preferably about 95% by mass or more, and may be 100% by mass. In this case, metal carbide with a reduced impurity content can be obtained in high yield. The fixed carbon content in the carbon source can be measured according to JIS M 8812:2006.

[0018] Among the above, non-edible biomass, particularly carbonized non-edible biomass, is preferred as biomass because the use of non-edible biomass eliminates the need to consider competition with food. In particular, the biomass preferably contains at least one of charcoal, pulp carbonized material, lignin carbonized material (lignin-containing component carbonized material), coconut shell carbonized material, bagasse carbonized material, and sorghum carbonized material, more preferably charcoal and / or pulp carbonized material, and even more preferably charcoal. Charcoal is readily available and easy to handle, and therefore has the advantage of being easily mixed uniformly with coke when used in combination with coke. Furthermore, charcoal and pulp carbonized material do not contain phosphorus compounds, or contain only small amounts of them, so the content of impurities such as calcium phosphide (metal phosphide) in the resulting metal carbide can be sufficiently reduced. Therefore, when such metal carbide is used to produce acetylene, the generation of toxic substances such as phosphine derived from the impurities can be effectively prevented, resulting in a high level of safety.

[0019] Among charcoal, it is preferable to use hard charcoal, since hard charcoal is less likely to be crushed when mixed with coke or in the subsequent heating step, making it easier to produce metal carbide more stably. Specific examples of charcoal include white charcoal, black charcoal, sawdust charcoal, industrial charcoal, etc. These charcoals may be used alone or in combination of two or more types. Specifically, it is preferable that a sample cut out from the carbon source to a size of 35 mm×35 mm×10 mm has a crushing strength of about 30 kgf or more as measured in accordance with JIS Z 8841:1993.

[0020] Briquettes and molded charcoal produced by burning briquettes can also be suitably used as carbon sources. Such briquettes can be obtained by pulverizing and sizing biomass using a pulverizer to obtain pulverized biomass, mixing the pulverized biomass and a binder in a mixer, and then molding the mixture in a molding machine. The crushing strength of these carbon sources is preferably about 30 kgf or more, more preferably about 35 kgf or more, and even more preferably about 40 kgf or more. The upper limit of the crushing strength of the carbon source is not particularly limited, but is about 60 kgf. The crushing strength of the carbon source can be, for example, about 30 kgf or more and 60 kgf or less. This makes it possible to suitably prevent collapse of the carbon source during charging or in an electric furnace.

[0021] Such carbon sources preferably have a volatile content of about 5% by mass or less, more preferably about 4% by mass or less, and even more preferably about 3% by mass or less, as measured in accordance with JIS M 8812:2006. The lower limit of the volatile content of the carbon source is not particularly limited, but is about 0.01% by mass. The volatile content of the carbon source can be, for example, about 0.01% by mass or more and about 5% by mass or less. This can suitably prevent the carbon source from burning during storage, etc. The content of phosphorus atoms in the carbon source is preferably about 200 ppm or less, more preferably about 150 ppm or less, about 100 ppm or less, about 60 ppm or less, about 50 ppm or less, and even more preferably about 40 ppm or less. In this case, even when the resulting metal carbide is used to produce acetylene, the generation of toxic substances such as phosphine can be sufficiently prevented, and safety can be further improved.

[0022] However, if the carbon source contains a small amount of phosphorus atoms, the odor of phosphorus compounds derived from calcium phosphide (metal phosphide) can be detected, making it possible to detect the leakage of highly flammable acetylene. This also improves safety. Specifically, the content of phosphorus atoms in the carbon source is preferably about 0.1 ppm or more, more preferably about 0.5 ppm or more, about 1 ppm or more, about 5 ppm or more, about 10 ppm or more, about 15 ppm or more, or about 20 ppm or more, more preferably about 25 ppm or more, and even more preferably about 30 ppm or more. The content of phosphorus atoms in the carbon source can be, for example, about 0.1 ppm or more and about 200 ppm or less.

[0023] The content of sulfur atoms in the carbon source is preferably 0.1% by mass (1000 ppm) or less, more preferably about 800 ppm or less, even more preferably about 600 ppm or less, particularly preferably about 400 ppm or less, and most preferably about 200 ppm or less. In this case, the generation of hydrogen sulfide can be suppressed, thereby improving safety. The generation of sulfur oxides can also be suppressed, thereby reducing corrosion and other problems in production equipment for metal carbide and bioplastics. The lower limit of the content of sulfur atoms in the carbon source is not particularly limited, but is about 50 ppm. The content of sulfur atoms in the carbon source can be, for example, about 50 ppm or more and 1000 ppm or less. The contents of phosphorus atoms and sulfur atoms in the carbon source can be measured in accordance with JIS M 8813:2004.

[0024] The ash content in the carbon source is preferably about 13% by mass or less, more preferably about 10% by mass or less, even more preferably about 5% by mass or less, and particularly preferably about 3% by mass or less. In this case, even if the ash is a compound that is reduced in an electric furnace, the amount is small, so that wasteful consumption of the carbon source and electricity can be suitably prevented or suppressed. It is also possible to reduce the number of times the work of periodically removing (cleaning) the reduced ash accumulated at the bottom of the electric furnace is required. Furthermore, it is also possible to improve the purity of the metal hydroxide that is produced as a by-product when acetylene is generated by reacting metal carbide with water. The lower limit of the ash content in the carbon source is not particularly limited and may be 0% by mass. The ash content in the carbon source can be, for example, about 0% by mass or more and 13% by mass or less. Here, ash refers to the inorganic residue that remains when a carbon source is completely combusted in air (usually at a temperature of about 550°C or higher and 800°C or lower). The ash content in the carbon source can be measured in accordance with JIS M 8812:2006.

[0025] On the other hand, examples of the metal source include alkaline earth metal oxides, alkaline earth metal carbonates, alkaline earth metal hydroxides, alkaline earth metal sulfates, alkaline earth metal chlorides, etc. These metal sources may be used alone or in combination of two or more. The metal source preferably contains an oxide of an alkaline earth metal, and more preferably contains calcium oxide. Calcium oxide (CaO) is an unstable substance obtained, for example, by thermal decomposition of calcium carbonate (CaCO) at approximately 900°C. Therefore, calcium oxide is suitable as a metal source due to its high reactivity. As the metal carbide, calcium carbide, barium carbide, and magnesium carbide are preferred.

[0026] <<Heating process>> Next, the mixture of the carbon source and the metal source is placed in an electric furnace (carbide electric furnace) and heated, whereby the carbon source and the metal source are reacted to obtain metal carbide. The heating temperature is not particularly limited, but is preferably about 1700°C to 2200°C, and more preferably about 1900°C to 2100°C. The heating time is also not particularly limited, but when the heating temperature is set as above, it is preferably about 2 minutes to 3 hours, and more preferably about 30 minutes to 1.5 hours. Heating under such heating conditions allows the reaction between the carbon source and the metal source to proceed sufficiently.

[0027] The heating atmosphere is preferably an argon atmosphere, which can prevent unnecessary combustion of carbon monoxide and hydrogen generated during the reaction between the carbon source and the metal source. The amount of the carbon source relative to 100 parts by mass of the metal source is preferably about 30 parts by mass to 400 parts by mass, more preferably about 50 parts by mass to 300 parts by mass, and even more preferably about 70 parts by mass to 200 parts by mass. By carrying out the reaction at such a ratio, the yield of metal carbide can be sufficiently increased. The carbon source and the metal source are preferably in particulate form, which increases the contact area between the carbon source and the metal source and improves the reaction efficiency between them.

[0028] The average particle size of the carbon source is not particularly limited, but is preferably about 8 mm or more and 50 mm or less, more preferably about 8 mm or more and 30 mm or less, and even more preferably about 8 mm or more and 10 mm or less. The average particle size of the metal source is not particularly limited, but is preferably about 8 mm or more and 50 mm or less, more preferably about 8 mm or more and 30 mm or less, and even more preferably about 8 mm or more and 10 mm or less. In this specification, the average particle size refers to the particle size (D50) at which the cumulative value reaches 50% in the volume-based cumulative particle size distribution obtained by laser diffraction scattering. The laser diffraction scattering method is measured in accordance with the method described in JIS Z 8825:2013 "Particle size analysis - Laser diffraction and scattering method."

[0029] When biomass is used as a carbon source and combined with coke, combustion of the biomass, which has a lower ignition temperature than coke, is initiated first, and the heat from this combustion is expected to promote the combustion of the coke. As a result, the heating temperature can be smoothly adjusted to the above range, where the reaction between the carbon source and the metal source proceeds smoothly. This effect is particularly pronounced when charcoal is used as a biomass. Charcoal has a high ratio of carbon atoms to hydrogen atoms, making it suitable for use in combination with coke. Charcoal is also preferred because it has lower electrical conductivity than coke and is less likely to cause electrical short circuits in an electric furnace. Furthermore, the use of charcoal has the advantage of preventing a significant increase in the manufacturing cost of metal carbide, since it does not require significant changes to the configuration of the electric furnace or the addition of new manufacturing equipment.

[0030] Prior to the heating (main heating), the mixture may be preheated at a temperature lower than the heating temperature described above. By performing such preheating, the amount of carbon source consumed in the main heating can be reduced and the yield of metal carbide can be further increased. Examples of fuels for preheating include charcoal, which has a low ignition temperature among substances contained in the carbon source, and electric furnace gas (a mixed gas of carbon monoxide and hydrogen) emitted during main heating. Using charcoal as the fuel for preheating allows for a smooth transition from preheating to main heating. On the other hand, using electric furnace gas as the fuel for preheating allows for effective use of energy while favorably preventing air pollution. In this heating step, the biomass content of the resulting metal carbide can be adjusted within the above range by changing the mixing ratio of biomass (charcoal) and coke. Therefore, the mass balance method can appropriately respond to fluctuations in demand because it is sufficient to change the mixing ratio of biomass and coke depending on the demand for biomass.

[0031] Furthermore, the gas containing at least carbon monoxide and hydrogen produced in the electric furnace in this heating step may be recovered. That is, the method for producing metal carbide may further include a step of recovering the gas containing at least carbon monoxide and hydrogen produced in the electric furnace. The recovered carbon monoxide and hydrogen may be used, for example, as an energy source for converting calcium carbonate to calcium oxide or an energy source for converting metal carbide to acetylene, or may be used to convert them into carbon compounds. In the latter case, the method for producing metal carbide may further include a step of reacting at least carbon monoxide with hydrogen to obtain a carbon compound, thereby enabling effective utilization of gases generated in the process for producing metal carbide. Examples of the carbon compound include acrylic acid, olefins (jet fuel), and acetylene black. Furthermore, it may be provided in the following aspects.

[0032] (1) Metal carbide as specified in ASTM D6866 14 Metal carbide having a biomass content of 0.01% or more and 100% or less as measured by C isotope analysis.

[0033] (2) The metal carbide according to (1) above, which is used to produce acetylene.

[0034] (3) The metal carbide according to (1) above, which is used to produce calcium carbonate.

[0035] (4) The metal carbide according to any one of (1) to (3) above, wherein the metal carbide reacts with pure water to generate acetylene, and the content of sulfur atoms in the metal carbide is 100 ppm or less.

[0036] (5) The metal carbide according to any one of (1) to (4) above, wherein the metal carbide reacts with pure water to generate acetylene, and the content of phosphorus atoms in the metal carbide is 1 ppm or more and 320 ppm or less.

[0037] (6) The metal carbide according to any one of (1) to (5) above, wherein the metal carbide reacts with pure water to generate acetylene, and the ash content in the metal carbide is 10 mass % or less.

[0038] (7) A method for producing a metal carbide, comprising the steps of: preparing a carbon source containing biomass and a metal source; and heating the carbon source and the metal source in an electric furnace to obtain the metal carbide according to any one of (1) to (6) above.

[0039] (8) The method for producing metal carbide according to (7) above, wherein the content of phosphorus atoms in the carbon source is 200 ppm or less.

[0040] (9) The method for producing metal carbide according to (8) above, wherein the content of the phosphorus atoms in the carbon source is 0.1 ppm or more.

[0041] (10) The method for producing metal carbide according to any one of (7) to (9) above, wherein the ash content in the carbon source is 13 mass % or less.

[0042] (11) The method for producing metal carbide according to any one of (7) to (10) above, wherein the content of sulfur atoms in the carbon source is 0.1 mass % or less.

[0043] (12) The method for producing metal carbide according to any one of (7) to (11) above, wherein the carbon source has a volatile content of 5 mass% or less as measured in accordance with JIS M 8812:2006.

[0044] (13) The method for producing metal carbide according to any one of (7) to (12) above, wherein the content of fixed carbon in the carbon source is 85 mass % or more.

[0045] (14) The method for producing metal carbide according to any one of (7) to (13) above, wherein the biomass contains at least one of charcoal, pulp carbonized material, lignin carbonized material, coconut shell carbonized material, bagasse carbonized material, and sorghum carbonized material.

[0046] (15) The method for producing metal carbide according to any one of (7) to (14) above, wherein a sample cut out from the carbon source to a size of 35 mm × 35 mm × 10 mm has a crushing strength of 30 kgf or more as measured in accordance with JIS Z 8841:1993.

[0047] (16) The method for producing metal carbide according to any one of (7) to (15) above, wherein the metal source contains an oxide of an alkaline earth metal.

[0048] (17) The method for producing metal carbide according to any one of (7) to (16) above, further comprising a step of recovering a gas produced in the electric furnace and containing at least carbon monoxide and hydrogen.

[0049] (18) The method for producing metal carbide according to (17) above, further comprising the step of reacting at least the carbon monoxide with the hydrogen to obtain a carbon compound.

[0050] (19) The method for producing metal carbide according to any one of (7) to (18) above, wherein the biomass is pulverized and sized using a pulverizer to obtain pulverized biomass, the pulverized biomass and a binder are mixed using a mixer, and then molded using a molding machine to obtain briquettes, and the briquettes are used as the carbon source.

[0051] (20) The method for producing metal carbide according to any one of (7) to (18) above, further comprising the steps of: preparing lignocellulosic biomass as the biomass; separating and recovering a lignin-containing component from the lignocellulosic biomass; carbonizing the lignin-containing component to obtain a lignin-containing component carbonized product; and using the lignin-containing component carbonized product as the carbon source. Of course, this is not the case.

[0052] Finally, while various embodiments of the present disclosure have been described, they are presented as examples and are not intended to limit the scope of the invention. The novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. Such embodiments and modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the inventions and their equivalents as defined in the claims. [Example]

[0053] Hereinafter, metal carbide and a method for producing metal carbide will be described in more detail using the following examples and comparative examples, but these are not limited to the following examples.

[0054] 1. Preparation of raw materials <Carbon source> White charcoal: Kishu Binchotan, manufactured by South Sky Nara charcoal: Charcoal manufactured by Yachi Forestry Co., Ltd. Sawdust charcoal: "Sawdust Binchotan" manufactured by Pearl Metal Co., Ltd. Palm kernel shells: PKS (Palm Kernel Shells) manufactured by EneLab Japan Bagasse: Dried bagasse manufactured by Bagasse Garden Co., Ltd. Anthracite: Vietnamese Hon Gay coal Wood chips: Komeri Natural Season Blend Smoking Chips (Value Pack) The white charcoal, Nara black charcoal, sawdust charcoal and anthracite were each crushed and sieved to an average particle size of about 10 mm before use. <Calcium source (metal source)> Calcium oxide: 99.9% calcium oxide, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. <Barium source (metal source)> Barium carbonate: 99.9% barium carbonate, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0055] 2. Metal carbide manufacturing Example 1 First, 111 parts by mass of white charcoal as a carbon source and 155 parts by mass of calcium oxide as a calcium source were mixed to obtain a mixture so that the amount of fixed carbon charged was 100 parts by mass. Next, this mixture was placed in a multipurpose high-temperature furnace (Fuji Denpa Kogyo Co., Ltd., "Hi-Multi Series") and heated at 2000°C for 1 hour while flowing argon at a rate of 7 L / hr. This produced calcium carbide.

[0056] Example 2 Calcium carbide was obtained in the same manner as in Example 1, except that 133 parts by mass of black charcoal was used as the carbon source. Example 3 Calcium carbide was obtained in the same manner as in Example 1, except that 111 parts by mass of sawdust charcoal was used as the carbon source.

[0057] Example 4 Calcium carbide was obtained in the same manner as in Example 1, except that 56 parts by mass of white charcoal and 59 parts by mass of anthracite were used as the carbon source. Example 5 Calcium carbide was obtained in the same manner as in Example 1, except that 11 parts by mass of white charcoal and 106 parts by mass of anthracite were used as the carbon source.

[0058] Example 6 Calcium carbide was obtained in the same manner as in Example 1, except that 1 part by mass of white charcoal and 116 parts by mass of anthracite were used as the carbon source.

[0059] Example 7 Coconut shells were placed in a multipurpose high-temperature furnace (Fuji Denpa Kogyo Co., Ltd., "High Multi Series") and heated at 800°C while flowing argon at a rate of 7 L / hr until the fixed carbon reached 90% by mass, yielding coconut shell carbide. Next, 111 parts by mass of coconut shell carbide was mixed with 195 parts by mass of calcium oxide as a calcium source to obtain a mixture. This mixture was then placed in a multipurpose high-temperature furnace and heated at 2000°C for 1 hour while flowing argon at a rate of 7 L / hr. This yielded calcium carbide.

[0060] Example 8 Bagasse was placed in a multipurpose high-temperature furnace (Fuji Denpa Kogyo Co., Ltd., "High Multi Series") and heated at 800°C while flowing argon at a rate of 7 L / hr until the fixed carbon reached 90% by mass, yielding bagasse charcoal. Next, 111 parts by mass of the bagasse charcoal was mixed with 195 parts by mass of calcium oxide as a calcium source to obtain a mixture. This mixture was then placed in a multipurpose high-temperature furnace and heated at 2000°C for 1 hour while flowing argon at a rate of 7 L / hr. This yielded calcium carbide.

[0061] Example 9 The bagasse charcoal obtained in Example 8 was pulverized using a disc mill to obtain bagasse charcoal powder (pulverized bagasse charcoal) with an average particle size of 350 μm. Next, 100 parts by mass of the bagasse charcoal powder and 8 parts by mass of asphalt binder were mixed in a batch mixer until the moisture content reached 7% by mass. This mixture was then molded at a linear pressure of 10 kN / cm using a double-roll molding machine with recesses measuring 34.8 mm x 30 mm x 9.4 mm to obtain bagasse charcoal briquettes. After measuring the crushing strength, 114 parts by mass of the bagasse charcoal briquettes were mixed with 195 parts by mass of calcium oxide as a calcium source to obtain a mixture. This mixture was then placed in a multipurpose high-temperature furnace and heated at 2000 °C for 1 hour while flowing argon at a rate of 7 L / hr. This produced calcium carbide.

[0062] Example 10 Wood chips were hydrolyzed using concentrated sulfuric acid, and then the residue was collected by filtration. The resulting residue was washed with hot water at 80°C, followed by acetone, ethyl acetate, and toluene to obtain wood chip-derived lignin. The resulting wood chip-derived lignin was then placed in a multipurpose high-temperature furnace (Fuji Denpa Kogyo Co., Ltd., "High Multi Series") and heated at 800°C while flowing argon at a rate of 7 L / hr until the fixed carbon reached 90% by mass, yielding wood chip-derived lignin carbonized material. Next, 111 parts by mass of the wood chip-derived lignin carbonized material was mixed with 195 parts by mass of calcium oxide as a calcium source to obtain a mixture. This mixture was then placed in a multipurpose high-temperature furnace and heated at 2000°C for 1 hour while flowing argon at a rate of 7 L / hr. This yielded calcium carbide.

[0063] Example 11 The wood chip-derived lignin obtained in Example 10 was heated at 300°C to obtain wood chip-derived lignin semi-carbonized material. 100 parts by mass of the wood chip-derived lignin semi-carbonized material and 8 parts by mass of asphalt binder were mixed in a batch mixer to obtain wood chip-derived lignin semi-carbonized pellets. The wood chip-derived lignin semi-carbonized pellets were then placed in a multipurpose high-temperature furnace (Fuji Denpa Kogyo Co., Ltd., "High Multi Series"), and heated at 800°C under a reduced pressure of 10 Pa at 20 MPa using a press until the fixed carbon content reached 90%, thereby obtaining wood chip-derived lignin molded charcoal. Next, 111 parts by mass of the wood chip-derived lignin molded charcoal was mixed with 195 parts by mass of calcium oxide as a calcium source to obtain a mixture. This mixture was then placed in a multipurpose high-temperature furnace and heated at 2000°C for 1 hour while flowing argon at a rate of 7 L / hr. This produced calcium carbide.

[0064] Example 12 A mixture was obtained by mixing 111 parts by mass of the wood chip-derived lignin carbonized material obtained in Example 10 with 411 parts by mass of barium carbonate as a barium source. Next, this mixture was placed in a multipurpose high-temperature furnace and heated at 1550°C for 1 hour while flowing argon at a rate of 7 L / hr. This produced barium carbide.

[0065] (Comparative Example) Calcium carbide was obtained in the same manner as in Example 1, except that 118 parts by mass of anthracite was used as the carbon source.

[0066] 3. Measurement 3-1. Measurement of biomass level The biomass carbon sources used in each of the Examples and Comparative Examples and the metal carbides obtained in each of the Examples and Comparative Examples were measured by accelerator mass spectrometry (AMS) in accordance with ASTM D6866, and the biomass degree was calculated according to the following formula. Biomass content (%) = biomass carbon source or metal carbide 14 Mass of C / Mass of all carbon atoms in biomass carbon source or metal carbide x 100

[0067] 3-2. Measurement of phosphorus and sulfur atom contents in biomass carbon sources and anthracite The contents of phosphorus atoms and sulfur atoms (phosphorus content and sulfur content) in the biomass carbon source and the anthracite were measured in accordance with JIS M 8813:2004. 3-3. Measurement of carbon atom (fixed carbon) content in biomass carbon sources and anthracite The carbon atom content (fixed carbon content) in the biomass carbon source and anthracite was measured in accordance with JIS M 8812:2006.

[0068] 3-4. Measurement of ash content in biomass carbon sources The ash content in the biomass carbon source (ash content) was measured according to JIS M 8812:2006. 3-5. Measurement of crushing strength of biomass carbon sources The biomass carbon source was molded into a sample measuring 35 mm x 35 mm x 10 mm, and the crushing strength of this sample was measured in accordance with JIS Z 8841:1993.

[0069] 3-6. Measurement of phosphorus atom content in metal carbide Acetylene gas was generated from the metal carbide according to JIS K 1901:2003. The phosphine content in the acetylene gas (phosphine content) was measured according to JIS K 1901:2003. The phosphorus atom content in the metal carbide (phosphorus content) was calculated from the phosphine content in the acetylene as follows.

number

[0070] 3-7. Measurement of sulfur atom content in metal carbide Acetylene gas was generated from the metal carbide in accordance with JIS K 1901:2003. The hydrogen sulfide content in the acetylene gas (hydrogen sulfide content) was measured in accordance with JIS K 1901:2003. The content of sulfur atoms in the metal carbide (sulfur content) was calculated from the hydrogen sulfide content in the acetylene as follows.

number

[0071] 3-8. Measurement of ash content in metal carbide Calcium hydroxide was obtained by reacting 100 parts by mass of calcium carbide from Examples 1 to 11 and Comparative Example with 58 parts by mass of pure water. The obtained calcium hydroxide was dried at 150°C until the water content was 0.1% by mass or less. The purity of the calcium hydroxide was measured in accordance with JIS K 8575:2025. Barium hydroxide was obtained by reacting 100 parts by mass of the barium carbide of Example 12 with 30 parts by mass of pure water. The obtained barium hydroxide was dried at 150°C until the water content was 0.1% by mass or less. The purity of the barium hydroxide was measured according to JIS K 1417-1992. The ash content in the metal carbide was calculated from the purity of calcium hydroxide or the purity of barium hydroxide measured as described above as follows.

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[0072] The results are shown in Tables 1 and 2 below. [Table 1]

[0073] [Table 2]

[0074] As shown in Tables 1 and 2, it was confirmed that metal carbides having a biomass content according to the mass balance can be produced.

Claims

1. A metal carbide, Specified in ASTM D6866 １４ A metal carbide having a biomass ratio of 0.01% or more and 100% or less as measured by a C isotope measurement method.

2. The metal carbide according to claim 1, A metal carbide used to produce acetylene.

3. The metal carbide according to claim 1, A metal carbide used in producing nitrolime.

4. The metal carbide according to claim 1, The metal carbide reacts with pure water to generate acetylene, A metal carbide having a sulfur atom content of 100 ppm or less.

5. The metal carbide according to claim 1, The metal carbide reacts with pure water to generate acetylene, The metal carbide has a phosphorus atom content of 1 ppm or more and 320 ppm or less.

6. The metal carbide according to claim 1, The metal carbide reacts with pure water to generate acetylene, The metal carbide has an ash content of 10 mass% or less.

7. A method for producing metal carbide, comprising: providing a carbon source comprising biomass and a metal source; and heating the carbon source and the metal source in an electric furnace to obtain the metal carbide according to any one of claims 1 to 6.

8. The method for producing metal carbide according to claim 7, The method for producing metal carbide, wherein the content of phosphorus atoms in the carbon source is 200 ppm or less.

9. The method for producing metal carbide according to claim 8, The method for producing metal carbide, wherein the content of the phosphorus atoms in the carbon source is 0.1 ppm or more.

10. The method for producing metal carbide according to claim 7, The method for producing metal carbide, wherein the carbon source has an ash content of 13 mass% or less.

11. The method for producing metal carbide according to claim 7, The method for producing metal carbide, wherein the content of sulfur atoms in the carbon source is 0.1 mass% or less.

12. The method for producing metal carbide according to claim 7, The method for producing metal carbide, wherein the carbon source has a volatile content of 5 mass% or less as measured in accordance with JIS M 8812:2006.

13. The method for producing metal carbide according to claim 7, The method for producing metal carbide, wherein the content of fixed carbon in the carbon source is 85 mass % or more.

14. The method for producing metal carbide according to claim 7, The method for producing metal carbide, wherein the biomass includes at least one of charcoal, pulp carbonized material, lignin carbonized material, coconut shell carbonized material, bagasse carbonized material, and sorghum carbonized material.

15. The method for producing metal carbide according to claim 7, A sample cut out from the carbon source to a size of 35 mm x 35 mm x 10 mm has a crushing strength of 30 kgf or more as measured in accordance with JIS Z 8841:1993.

16. The method for producing metal carbide according to claim 7, The method for producing metal carbide, wherein the metal source comprises an oxide of an alkaline earth metal.

17. The method for producing metal carbide according to claim 7, The method for producing metal carbide further comprises a step of recovering gas produced in the electric furnace and containing at least carbon monoxide and hydrogen.

18. 18. The method for producing metal carbide according to claim 17, The method for producing metal carbide further comprises a step of reacting at least the carbon monoxide with the hydrogen to obtain a carbon compound.

19. The method for producing metal carbide according to claim 7, A method for producing metal carbide, comprising: pulverizing and sieving the biomass using a pulverizer to obtain pulverized biomass; mixing the pulverized biomass with a binder using a mixer; and molding the mixture using a molding machine to obtain briquettes; and using the briquettes as the carbon source.

20. The method for producing metal carbide according to claim 7, A method for producing metal carbide, comprising: preparing lignocellulose-based biomass as the biomass; separating and recovering lignin-containing components from the lignocellulose-based biomass; carbonizing the lignin-containing components to obtain lignin-containing component carbonized materials; and using the lignin-containing component carbonized materials as the carbon source.

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