Explosive composition for diamond synthesis

Abstract

Provided is an explosive composition for diamond synthesis which enables the production of diamond particles having a relatively large particle size.　This explosive composition for diamond synthesis comprises an explosive component, a carbon material which may be constituted by the explosive component, and diamond particles, wherein the total proportion of the explosive component, the carbon material and the diamond particles relative to the total amount of the explosive composition for diamond synthesis is 99 mass% or greater. Preferably, the crystallite size of primary particles of the diamond particles determined by XRD is not more than 100 nm.

Description

[Technical Field]

[0001] This disclosure relates to an explosive composition for diamond synthesis. The disclosure also relates to an explosive body obtained using the explosive composition for diamond synthesis, and a method for producing diamond particles using the explosive body. This application claims priority from Japanese Patent Application No. 2020-057636, filed on March 27, 2020, the contents of which are incorporated herein by reference. [Background technology]

[0002] In recent years, the development of fine particle diamond materials called nanodiamonds has been progressing. The detonation method is known as a method for synthesizing nanodiamonds. In the detonation method, for example, an explosive is exploded in a sealed container, and the explosive components used undergo partial incomplete combustion, liberating carbon, which is used as a raw material to generate nanodiamonds by the action of the pressure and energy of the shock wave generated by the explosion. Technologies related to such detonation methods are described, for example, in Patent Documents 1 to 3 listed below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-289677 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-144903 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-113310 [Patent Document 4] Japanese Patent Application Publication No. 2-241536 [Patent Document 5] International Publication No. 2007 / 001031 Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, for applications requiring advanced properties such as the fluorescent and magnetic properties of the nitrogen vacancy centers incorporated in nanodiamonds, there is a growing demand for technology to control the primary particle size of nanodiamonds. For example, with regard to fluorescent properties, it is assumed that the larger the size of nanodiamond particles, the more advantageous it is for the excited state to emit fluorescence. For this reason, there is a demand for technology to produce nanodiamonds with relatively large diameters.

[0005] However, although the yield of nanodiamonds has improved dramatically through optimization of the manufacturing method, little has been developed to control the particle size.The particle size of nanodiamonds obtained by the detonation method is thought to depend on the temperature and pressure at the time of detonation, but the detonation velocity of the explosives is invariant as a property of each explosive in the mixture, so it cannot be controlled.

[0006] In addition, Patent Document 4 describes that by using a molding formed from an explosive composition that is made by compounding diamond powder and paraffin with explosive components, the yield of diamond production increases, but does not disclose that diamonds with a relatively large diameter can be obtained.In addition, Patent Document 5 discloses that adamantanediol is added to explosive components, mixed, and melted and filled to obtain a molding of an explosive composition, and describes that this method can obtain ultrafine single-crystal diamonds with an average particle size that is smaller than conventional ones.

[0007] Therefore, an object of the present disclosure is to provide an explosive composition for diamond synthesis that can produce diamond particles having a relatively large diameter. Another object of the present disclosure is to provide a method for producing diamond particles having a relatively large diameter. [Means for solving the problem]

[0008] As a result of intensive research to achieve the above object, the inventors of the present disclosure have found that diamond particles can be embedded as seed crystals, and that an explosive composition in which the proportions of explosive components, carbon raw materials, and diamond particles are high can produce diamond particles with a relatively large diameter.Furthermore, they have found that diamond particles with a relatively large diameter can be produced by embedding diamond particles or adamantanes as seed crystals and molding an explosive body by a compression method.The present disclosure relates to a product completed based on these findings.

[0009] The present disclosure relates to an explosive composition for diamond synthesis, which comprises an explosive component, a carbon raw material which may be contained as the explosive component, and diamond particles, The explosive composition for diamond synthesis is provided, in which the total proportion of the explosive component, the carbon raw material, and the diamond particles is 99 mass % or more based on the total amount of the explosive composition for diamond synthesis.

[0010] The primary particles of the diamond particles preferably have a crystallite size of 100 nm or less as measured by XRD.

[0011] The diamond particles may comprise diamond clusters, and preferably comprise detonation diamond particles.

[0012] The explosive component preferably contains an explosive component that serves as the carbon raw material.

[0013] The explosive component serving as the carbon raw material preferably contains a compound having a nitro group.

[0014] The diamond particles are preferably contained in an amount of 15 parts by mass or less per 100 parts by mass of the total amount of the explosive components.

[0015] The explosive component preferably contains 2,4,6-trinitrotoluene and cyclotrimethylenetrinitramine, and the mass ratio of 2,4,6-trinitrotoluene to cyclotrimethylenetrinitramine [former / latter] in the explosive component is preferably 30 / 70 to 95 / 5.

[0016] The present disclosure also provides an explosive body for diamond synthesis, which is a compressed product of the explosive composition for diamond synthesis.

[0017] The present disclosure also provides an explosive body for diamond synthesis, which is a compressed explosive composition containing an explosive component, a carbon raw material that may be contained as the explosive component, and an adamantane.

[0018] The present disclosure also provides a method for producing diamond particles, which includes a detonation step of detonating the explosive component in the diamond synthesis explosive body to obtain diamond particles having a larger diameter than the diamond particles obtained when the seed crystal diamond particles or the adamantanes are not blended.

[0019] Preferably, the diamond particles obtained from the detonation process comprise single crystal diamond. [Effects of the Invention]

[0020] According to the explosive composition for diamond synthesis and explosive body for diamond synthesis of the present disclosure, diamond particles having a relatively large diameter can be produced compared to when diamond particles as seed crystals are not embedded. DETAILED DESCRIPTION OF THE INVENTION

[0021] [Explosive composition] An explosive composition for diamond synthesis according to one embodiment of the present disclosure (hereinafter, sometimes simply referred to as "explosive composition") contains at least an explosive component, a carbon raw material, and diamond particles as seed crystals. The carbon raw material may be contained as the explosive component. In this case, the explosive composition may or may not contain a carbon raw material other than the explosive component.

[0022] When the explosive body formed from the explosive composition is subjected to detonation method to detonate the explosive components, the diamond particles act as seed crystals, and the carbon raw material is converted into diamond by detonation, causing the seed crystals to grow, and diamond particles with a larger diameter can be obtained than the diamond particles obtained when the seed crystal particles are not embedded in the explosive composition.This is presumably because the diamond particles are compounded in advance as seed crystals in the explosive composition, thereby suppressing the generation of new diamond seed crystals generated from the carbon raw material, and allowing the diamonds derived from the carbon raw material to form on the surface of the diamond particles that are seed crystals.

[0023] As the explosive component, for example, a compound having a nitro group (nitro compound) is preferred, and more preferably a compound having three or more nitro groups. Examples of such nitro compounds include aromatic nitro compounds (preferably tri- or tetranitrobenzene which may be substituted with an amino group and / or a methyl group), nitroamines (preferably C 3-6 Examples of explosive components include alkyl (3-6 nitro)amines, and nitrate esters. Specific examples include cyclotrimethylenetrinitramine (RDX), i.e., hexogen, 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenylmethylnitramine, cyclotetramethylenetetranitramine, i.e., octogen, nitroguanidine, pentaerythritol tetranitrate (PENT), diazonitrophenol (DDNP), tetryl (tetranitromethylaniline), and HMX (tetramethylenetetranitroamine). The above explosive components may be used singly or in combination.

[0024] The explosive component preferably contains an explosive component as the carbon raw material. Examples of such explosive components include aromatic compounds having three or more nitro groups, with TNT being preferred. The explosive component particularly preferably contains TNT and RDX. TNT is effective as a carbon raw material, and RDX tends to significantly contribute to increasing the particle size of the resulting diamond particles. In this case, the mass ratio of TNT to RDX (TNT / RDX) is, for example, within the range of 30 / 70 to 95 / 5, preferably 40 / 60 to 90 / 10, more preferably 51 / 49 to 80 / 20, and even more preferably 55 / 45 to 70 / 30. When the mass ratio is 95 / 5 or less (particularly, 80 / 20 or less), the mass ratio of RDX is high, and the detonation velocity of TNT is accelerated by RDX, which tends to make it easier to obtain large-diameter diamond particles. Furthermore, when the mass ratio is within the above range, the yield of diamond particles tends to be high.

[0025] The content of the explosive component in the explosive composition is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, relative to the total amount (100% by mass) of the explosive composition.

[0026] The explosive composition contains at least diamond particles as the seed crystals, and the diamond particles may be of one type or two or more types.

[0027] The diamond particles used as the seed crystals are preferably nano-sized diamond particles (nanodiamond particles), and known or conventional nanodiamond particles can be used. The nanodiamond particles may be nanodiamond particles with modified nanodiamond surfaces (surface-modified nanodiamond particles), or may be nanodiamond particles that are not surface-modified. Note that the non-surface-modified nanodiamond particles have hydroxyl groups (-OH) on their surfaces. Only one type of diamond particle may be used, or two or more types may be used.

[0028] The diamond particles preferably include primary diamond particles, and may also include secondary particles (diamond clusters) formed by aggregation (adhesion) of a plurality of the primary particles.

[0029] As the diamond particles, for example, detonation diamond particles (i.e., diamond particles produced by detonation method) and high-temperature high-pressure diamond particles (i.e., diamond particles produced by high-temperature high-pressure method) can be used.Among them, detonation diamond particles are preferred because they can produce single crystal diamond and the particle diameter of the primary particles is small, being one digit nanometer.

[0030] Above-mentioned detonation diamond particles include air-cooled detonation diamond particles (i.e., diamond particles produced by air-cooled detonation method) and water-cooled detonation diamond particles (i.e., diamond particles produced by water-cooled detonation method).Among them, air-cooled detonation diamond particles are preferred because primary particles are smaller than water-cooled detonation diamond particles.

[0031] The crystallite diameter of the primary particle of the above-mentioned diamond particle by X-ray diffraction (XRD method) is preferably 100nm or less, more preferably 50nm or less, even more preferably 10nm or less, particularly preferably 7nm or less.The lower limit of the above-mentioned crystallite diameter is, for example, 1nm, and may be 4nm.When the primary particle of the above-mentioned diamond particle has the above-mentioned crystallite diameter, the particle diameter of the diamond particle obtained when carrying out detonation method using the above-mentioned explosive composition is likely to become larger.

[0032] The content of the diamond particles in the explosive composition is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, relative to 100 parts by mass of the total amount of the explosive components.If the content is small, the amount of carbon raw material per seed crystal is large, so the particle diameter of the diamond particles obtained by the detonation method using the explosive composition tends to be larger.In particular, if the content is 15 parts by mass or less, it is easier to obtain diamond particles with large particle diameters.In order to increase the number of diamond particles obtained, the content is, for example, 0.05 parts by mass or more, preferably 0.08 parts by mass or more.

[0033] The carbon raw material may contain other carbon raw materials other than the explosive component that acts as the carbon raw material. Examples of the other carbon raw materials include known or conventional carbon raw materials used in detonation methods, such as substituted or unsubstituted alicyclic hydrocarbon compounds, graphite, carbon nanotubes, and fullerenes. Examples of the substituted or unsubstituted alicyclic hydrocarbon compounds include cycloalkanes such as cyclohexanol, cyclopentanone, and dimethylcyclohexane; adamantane derivatives such as adamantanol; and cycloalkenes such as dicyclopentadiene and nobornene. Only one type of the carbon raw material may be used, or two or more types may be used.

[0034] The explosive composition may contain other components in addition to the above-mentioned components. Examples of the other components include binder polymers, plasticizers, antioxidants, etc. Only one of the other components may be used, or two or more of the other components may be used.

[0035] The total content (total ratio) of the explosive component, the carbon raw material, and the diamond particles in the explosive composition is 99% by mass or more, preferably 99.5% by mass or more, and more preferably 99.8% by mass or more, relative to the total amount (100% by mass) of the explosive composition. By making the total ratio 99% by mass or more, large-diameter diamond particles can be obtained.

[0036] [Explosives for diamond synthesis] The explosive body for diamond synthesis can be manufactured using the explosive composition. That is, the explosive body for diamond synthesis according to one embodiment of the present disclosure is an explosive body for diamond synthesis formed from an explosive composition for diamond synthesis containing an explosive component, a carbon raw material that may be contained as the explosive component, and diamond particles. The total proportion of the explosive component, the carbon raw material, and the diamond particles in the explosive body is preferably within the range exemplified and explained as the total proportion in the explosive composition above.

[0037] The explosive body can be produced by, for example, a pouring method or a compression method (compression method). In the pouring method, if the binder polymer is included, a mixed composition containing reactive components such as polymerizable components and crosslinking agents that will form the binder polymer, particles of the explosive component, and particles of the diamond particles is poured into a mold and then cured, thereby forming an explosive body. In the compression method, if the binder polymer is included, first, the binder polymer dissolved in a solvent, explosive component particles, and diamond particles are mixed in water, and the solvent is evaporated from the mixture to produce composite particles in which the explosive component particles are coated with a binder polymer on their surfaces. Next, the composite particles or explosive component particles and diamond particles thus obtained are compressed in a compression container while being heated as necessary. This forms an explosive body. In particular, in the pouring method, the diamond particles, which serve as seed crystals, tend to settle when poured into a mold, whereas in the squeezing method, it is easy to disperse the diamond particles in the explosive body, so it is preferable that the explosive body be one produced by the compression method (a compressed material).

[0038] In addition, according to another embodiment of the present disclosure, the explosive body for diamond synthesis is formed by a compaction method from an explosive composition for diamond synthesis containing an explosive component, a carbon raw material that may be contained as the explosive component, and adamantanes (i.e., a compacted product of the explosive composition for diamond synthesis). When the explosive body is subjected to a detonation method to explode the explosive component, the adamantanes, which are the smallest skeleton of diamond, act as seed crystals, and the carbon raw material is converted into diamond by detonation, causing the seed crystals to grow, resulting in diamond particles with a larger diameter than those obtained when seed crystal particles are not embedded in the explosive composition. This is presumably because the adamantane particles are incorporated into the explosive composition in advance as seed crystals, thereby suppressing the generation of new diamond seed crystals from the carbon raw material and allowing diamonds derived from the carbon raw material to form on the surface of the adamantane particles, which are the seed crystals. The preferred embodiments of the explosive composition containing adamantanes as seed crystals are the same as the preferred embodiments described above for the explosive composition containing diamond particles as seed crystals, and the preferred embodiments of the crystallite size and content of the primary particles of adamantanes as determined by XRD method are the same as the crystallite size and content of the diamond particles.

[0039] In particular, in the explosive composition containing the adamantanes as seed crystals, it is preferable to include an explosive component as the carbon raw material. The explosive component is preferably an aromatic compound having three or more nitro groups, with TNT being particularly preferred. The explosive component particularly preferably includes TNT and RDX. TNT is effective as a carbon raw material, and RDX tends to significantly contribute to increasing the particle size of the resulting diamond particles. In this case, the mass ratio of TNT to RDX (TNT / RDX) is, for example, within the range of 30 / 70 to 95 / 5, preferably 40 / 60 to 90 / 10, more preferably 51 / 49 to 80 / 20, and even more preferably 55 / 45 to 70 / 30. When the mass ratio is 95 / 5 or less (particularly 80 / 20 or less), the mass ratio of RDX is high, and the detonation velocity of TNT is accelerated by RDX, which tends to make it easier to obtain large-diameter diamond particles. Furthermore, when the mass ratio is within the above range, the yield of diamond particles tends to be high.

[0040] Adamantanes as the seed crystals include adamantane and adamantane derivatives such as adamantanol. Among them, adamantane is preferred from the viewpoint of easily obtaining diamond particles with a large particle size. Only one type of adamantane may be used, or two or more types may be used.

[0041] A detonator is inserted into the explosive body. The detonator is a component for detonating the explosive body and is fitted into a hole provided in the explosive body to be attached to the explosive body. The detonator has a structure in which, for example, a detonator section buried in the explosive body and a booster section located inside and outside the explosive body are adjacently integrated. Examples of the detonator in the detonator section include an instantaneous electric detonator, a delayed electric detonator, an anti-static detonator, an electronic delay detonator, and a fuse-type detonator. Examples of the booster charge in the booster charge section include highly sensitive explosives containing, as a base material, 2,4,6-trinitrophenylmethylnitramine, pentaerythritol tetranitrate, RDX, a mixture of TNT and RDX, or the like.

[0042] [Manufacturing method of diamond particles] The explosive body can be used for diamond synthesis by detonation. By carrying out the detonation method using the explosive body, diamond particles having a particle size larger than that obtained when diamond particles or adamantanes as seed crystals are not blended can be produced.

[0043] The method for producing the diamond particles includes a detonation step in which the explosive component in the explosive body is detonated to obtain diamond particles having a larger diameter than diamond particles obtained when the seed crystal is not blended.

[0044] (detonation process) In the above-mentioned detonation process, the detonation method can be air-cooled detonation method and water-cooled detonation method.Among them, air-cooled detonation method is preferable because it can obtain diamond particles with smaller primary particles than water-cooled detonation method.Detonation can be carried out under air atmosphere, or under inert gas atmosphere such as nitrogen atmosphere, argon atmosphere, or carbon dioxide atmosphere.

[0045] An embodiment of the air-cooled detonation method will be described. In the detonation process performed by the air-cooled detonation method, first, a shaped explosive (an explosive body with an explosive part inserted) is placed inside a pressure-resistant container for detonation, and the container is sealed in a state where atmospheric gas at normal pressure and the explosive coexist inside the container. The container is made of, for example, iron, and has a volume of, for example, 0.5 to 40 m 3 is.

[0046] In the detonation process, the explosive body is detonated in the container by detonating, for example, an electric detonator in the detonation section. Detonation refers to an explosion caused by a chemical reaction in which the flame front of the reaction moves at a high speed exceeding the speed of sound. During detonation, the explosive body used undergoes partial incomplete combustion, liberating carbon, which is used as raw material, and diamonds are generated by the action of the pressure and energy of the shock wave generated by the explosion. At this time, diamonds are generated so as to adhere to the surface of seed crystal particles, thereby forming relatively large diamond particles. The formed diamond particles are very firmly aggregated between adjacent primary particles or crystallites due to the action of van der Waals forces and the Coulomb interaction between crystal planes, forming an aggregate.

[0047] Next, the container is left to cool at room temperature for about 24 hours, and the temperature of the container and its interior is lowered. After this cooling, the crude diamond particle product (including the aggregates of diamond particles and soot generated as described above) adhering to the inner wall of the container is scraped off with a spatula, and the crude diamond particle product is recovered. By the above method, the crude diamond particle product (crude diamond particle product) can be obtained. Furthermore, by performing the above detonation process as many times as necessary, it is possible to obtain a desired amount of crude diamond particle product.

[0048] The primary particle diameter of the diamond particles obtained through the detonation process is larger than that of the seed crystal particles blended in the explosive composition.The crystallite diameter of the primary particles of the diamond particles obtained through the detonation process, as measured by X-ray diffraction (XRD method), is larger than that of the seed crystal particles, and is preferably 100 nm or less, more preferably 50 nm or less, even more preferably 10 nm or less, and particularly preferably 8 nm or less.The lower limit of the crystallite diameter is, for example, 1 nm, and may be 5 nm, 6 nm, or 7 nm.

[0049] The BET specific surface area of ​​the primary particles of the diamond particles obtained through the detonation process is, for example, 100 to 1000 m 2 / g, preferably 150 to 500m 2 / g, more preferably 170 to 300m2 / g. Since the diamond particles obtained by the above production method have a relatively large diameter, it is possible to obtain diamond particles having a BET specific surface area within the above range.

[0050] As an explosion method for producing diamond particles using an explosive, for example, a powder mixture containing diamond particles and a metal compound is detonated with an explosive separated from the powder mixture by a partition wall, and the diamond particles are exposed to a high-temperature, high-pressure environment, thereby causing multiple diamond particles in the powder mixture to adhere and unite to obtain large-diameter diamond particles (the implosion method).The large-diameter diamond particles obtained by the implosion method are produced by uniting multiple diamond particles, and therefore the primary particles are polycrystalline diamond particles.On the other hand, by undergoing the detonation process using the explosive body, the primary particles of the seed crystal can be grown rather than uniting multiple diamond particles, thereby obtaining single-crystal diamond.

[0051] (Acid treatment process) An acid treatment step may be performed following the detonation step. In the acid treatment step, a strong acid is applied to the raw material diamond particle crude product in, for example, an aqueous solvent to remove metal oxides. The diamond particle crude product obtained by the detonation method is likely to contain metal oxides, such as oxides of Fe, Co, Ni, etc., derived from the container used in the detonation method. For example, by applying a strong acid in an aqueous solvent, metal oxides can be dissolved and removed from the diamond particle crude product (acid treatment). The strong acid used in this acid treatment is preferably a mineral acid, such as hydrochloric acid, hydrofluoric acid, sulfuric acid, nitric acid, or aqua regia. One or more of the strong acids may be used. The concentration of the strong acid used in the acid treatment is, for example, 1 to 50% by mass. The acid treatment temperature is, for example, 70 to 150°C. The acid treatment time is, for example, 0.1 to 24 hours. The acid treatment can be performed under reduced pressure, normal pressure, or increased pressure. After the acid treatment, the solid content (including diamond aggregates) is washed with water, for example, by decantation. It is preferable to repeatedly wash the solid matter with water by decantation until the pH of the precipitation liquid reaches, for example, 2 to 3. When the content of metal oxides in the crude diamond particle product obtained by the detonation method is low, the acid treatment described above may be omitted.

[0052] (Oxidation treatment process) The oxidation treatment process is a process in which graphite is removed from the crude diamond particle product using an oxidizing agent. The crude diamond particle product obtained by the detonation method contains graphite, which is derived from carbon materials such as carbon liberated by the partial incomplete combustion of the explosive used, but which did not form diamond. Graphite can be removed from the crude diamond particle product by applying an oxidizing agent to the crude diamond particle product in an aqueous solvent. Furthermore, oxygen-containing groups such as carboxyl groups and hydroxyl groups can be introduced onto the diamond particle surface by applying an oxidizing agent.

[0053] Examples of oxidizing agents used in this oxidation treatment include chromic acid, chromic anhydride, dichromic acid, permanganic acid, perchloric acid, nitric acid, mixtures thereof, mixed acids of at least one acid selected from these with another acid (such as sulfuric acid), and salts thereof. Among these, the use of mixed acids (particularly mixed acids of sulfuric acid and nitric acid) is preferred because it is environmentally friendly and has an excellent effect of oxidizing and removing graphite.

[0054] The mixing ratio of sulfuric acid to nitric acid (former / latter; mass ratio) in the mixed acid is preferably, for example, 60 / 40 to 95 / 5, since graphite can be efficiently oxidized and removed at temperatures of, for example, 130°C or higher (particularly preferably 150°C or higher; the upper limit is, for example, 200°C) even under pressures near atmospheric pressures (for example, 0.5 to 2 atm). The lower limit is preferably 65 / 35, more preferably 70 / 30. The upper limit is preferably 90 / 10, more preferably 85 / 15, and even more preferably 80 / 20. When the mixing ratio is 60 / 40 or higher, the content of sulfuric acid, which has a high boiling point, is high, so that the reaction temperature is, for example, 120°C or higher under pressures near atmospheric pressures, and graphite removal efficiency tends to be improved. When the mixing ratio is 95 / 5 or less, the content of nitric acid, which significantly contributes to graphite oxidation, is high, so that graphite removal efficiency tends to be improved.

[0055] The amount of oxidizing agent (particularly the mixed acid) used is, for example, 10 to 50 parts by mass, preferably 15 to 40 parts by mass, and more preferably 20 to 40 parts by mass, per part by mass of the crude diamond particle product. The amount of sulfuric acid used in the mixed acid is, for example, 5 to 48 parts by mass, preferably 10 to 35 parts by mass, and more preferably 15 to 30 parts by mass, per part by mass of the crude diamond particle product. The amount of nitric acid used in the mixed acid is, for example, 2 to 20 parts by mass, preferably 4 to 10 parts by mass, and more preferably 5 to 8 parts by mass, per part by mass of the crude diamond particle product.

[0056] When the mixed acid is used as the oxidizing agent, a catalyst may be used together with the mixed acid. The use of a catalyst can further improve the efficiency of graphite removal. Examples of the catalyst include copper (II) carbonate. The amount of catalyst used is, for example, about 0.01 to 10 parts by mass per 100 parts by mass of the crude diamond particle product.

[0057] The oxidation treatment temperature is, for example, 100 to 200° C. The oxidation treatment time is, for example, 1 to 24 hours. The oxidation treatment can be carried out under reduced pressure, normal pressure, or increased pressure.

[0058] (Alkaline hydrogen peroxide treatment process) Even after the acid treatment process, if metal oxides remain on the diamond particles, they form aggregates (secondary particles, diamond clusters) in which the primary particles interact strongly with each other. In such cases, the diamond particles may be treated with an alkali and hydrogen peroxide in an aqueous solvent. This removes the metal oxides remaining on the diamond particles and promotes separation of the primary particles from the aggregates. Examples of alkalis used in this treatment include sodium hydroxide, ammonia, and potassium hydroxide. In the alkaline peroxide treatment, the alkali concentration is, for example, 0.1 to 10% by mass, the hydrogen peroxide concentration is, for example, 1 to 15% by mass, the treatment temperature is, for example, 40 to 100°C, and the treatment time is, for example, 0.5 to 5 hours. The alkaline peroxide treatment can be performed under reduced pressure, normal pressure, or increased pressure.

[0059] After the oxidation treatment step or the alkaline hydrogen peroxide treatment step, it is preferable to remove the supernatant liquid by, for example, decantation. Furthermore, during decantation, it is preferable to wash the solids with water. Although the supernatant liquid is colored at the beginning of washing, it is preferable to repeatedly wash the solids with water until the supernatant liquid becomes transparent to the naked eye.

[0060] (Crushing process) The diamond particles may be subjected to a crushing treatment if necessary. For the crushing treatment, for example, a high shear mixer, a high shear mixer, a homomixer, a ball mill, a bead mill, a high-pressure homogenizer, an ultrasonic homogenizer, a colloid mill, etc. can be used. The crushing treatment may be performed in a wet manner (for example, a crushing treatment in a state of being suspended in water, etc.) or in a dry manner. When performed in a dry manner, it is preferable to provide a drying step before the crushing treatment. Furthermore, when an oxidation treatment or a hydrogenation treatment is performed, the crushing treatment step may be performed after these treatments.

[0061] (drying process) After the alkaline hydrogen peroxide treatment step, it is preferable to provide a drying step. For example, the liquid content of the diamond particle-containing solution obtained through the alkaline hydrogen peroxide treatment step is evaporated using a spray dryer or evaporator, and the resulting residual solid content is then dried by heating in a drying oven. The heating and drying temperature is, for example, 40 to 150°C. Diamond particles are obtained through this drying step.

[0062] Furthermore, the diamond particles may be subjected to an oxidation treatment (e.g., oxygen oxidation) or a reduction treatment (e.g., hydrogenation) in the gas phase, as needed. By performing an oxidation treatment in the gas phase, diamond particles having many C=O groups on the surface can be obtained. By performing a reduction treatment in the gas phase, diamond particles having many CH groups on the surface can be obtained.

[0063] The diamond particles obtained by the above production method can also be reused as diamond particles as seed crystals in the explosive composition.

[0064] Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. Each configuration and combination thereof in each embodiment is an example, and addition, omission, substitution, and other modifications of configurations are possible as appropriate within the scope of the present disclosure. Furthermore, each invention according to this disclosure is not limited by the embodiments or the following examples, but is limited only by the scope of the claims. [Example]

[0065] Hereinafter, one embodiment of the present disclosure will be described in more detail based on examples.

[0066] Example 1 An explosive composition (approximately 60 g) was prepared by adding 10 parts by mass of cluster nanodiamond (primary particle crystallite diameter: 4.3-4.6 nm) as seed crystals to 100 parts by mass of explosive components consisting of 2,4,6-trinitrotoluene (TNT) and cyclotrimethylenetrinitramine (RDX) (the mass ratio of TNT to RDX (TNT / RDX) was 60 / 40). Next, an explosive body was manufactured using the above explosive composition by the compression method. Then, the nanodiamond production process (detonation process) was carried out using the explosive body. In this process, the explosive body formed above, which was equipped with an electric detonator, was placed inside a pressure-resistant container for detonation, and the container was sealed. The container was made of iron and had a volume of 0.094 m 3 Next, an electric detonator was detonated, causing the explosive to detonate inside the container. The container and its interior were then allowed to cool at room temperature for 24 hours. After cooling, the crude nanodiamond product (including the aggregates of nanodiamond particles and soot produced by the detonation method) adhering to the inner wall of the container was scraped off with a spatula, and the crude nanodiamond product was recovered.

[0067] The crude nanodiamond product obtained in the detonation process was then subjected to an oxidation treatment process. Specifically, the precipitate liquid (containing nanodiamond aggregates) obtained through decantation after acid treatment was mixed with 2800 g of a mixed acid of concentrated sulfuric acid and concentrated nitric acid (the mass ratio of concentrated sulfuric acid to concentrated nitric acid was 11:1) and 15 g of the crude nanodiamond product, and the treatment was carried out at 150 ° C for 10 hours. Next, the precipitate liquid (liquid containing cluster nanodiamonds) obtained through water washing treatment was subjected to a drying process to obtain a dry powder (cluster nanodiamonds of Example 1). As the drying method in the drying process, evaporation to dryness using an evaporator was adopted.

[0068] Example 2 An explosive composition and an explosive body were prepared in the same manner as in Example 1, except that the amount of cluster nanodiamond added as a seed crystal was 0.5 parts by mass. Then, using the explosive body, the cluster nanodiamond of Example 2 was prepared by the detonation method in the same manner as in Example 1.

[0069] Example 3 An explosive composition and an explosive body were prepared in the same manner as in Example 1, except that the amount of cluster nanodiamond added as a seed crystal was 0.1 parts by mass. Then, using the explosive body, the cluster nanodiamond of Example 3 was prepared by the detonation method in the same manner as in Example 1.

[0070] Example 4 Except for using adamantane as a seed crystal instead of cluster nanodiamond, an explosive composition and an explosive body were prepared in the same manner as in Example 1. Then, using the explosive body, cluster nanodiamond of Example 4 was prepared by the detonation method in the same manner as in Example 1.

[0071] Example 5 An explosive composition and an explosive body were prepared in the same manner as in Example 4, except that the amount of adamantane added as a seed crystal was 0.5 parts by mass. Then, using the explosive body, the cluster nanodiamond of Example 5 was prepared by the detonation method in the same manner as in Example 1.

[0072] Comparative Example 1 A blasting agent composition and a blasting agent body were produced in the same manner as in Example 1, except that cluster nanodiamond as seed crystals was not added. Then, using the blasting agent body, cluster nanodiamond was produced by the detonation method in the same manner as in Example 1.

[0073] (Evaluation) Regarding the cluster nanodiamond powders obtained in the examples and comparative examples, they were analyzed by X-ray diffraction method (XRD), and the crystallite size was analyzed by Scherrer's formula. Also, the BET specific surface area of 40 mg of the above cluster nanodiamond powder was measured. The results are shown in Table 1. The measurement conditions for X-ray diffraction analysis and BET specific surface area are as shown below. <X-ray diffraction analysis> X-ray diffractometer: Trade name "Full-automatic multi-purpose X-ray diffractometer", manufactured by Rigaku Corporation <BET specific surface area measurement> High-precision gas / vapor adsorption amount measuring device: Trade name "BELSORP-miniII", manufactured by Macrotrac Bell Co., Ltd. Preliminary drying: Temperature 120 °C and under vacuum conditions for 3 hours Measurement temperature: -296 °C

[0074] [Table 1] TIFF0007756634000002.tif55150

[0075] As can be seen from Table 1, according to the detonation method, when nano-diamond particles or adamantanes as seed crystals are added to the blasting agent composition (Example), larger-sized nano-diamond particles were obtained compared to the case where they were not added (Comparative Example 1).

[0076] Hereinafter, variations of the invention according to the present disclosure will be described. [Appendix 1] A blasting agent composition for diamond synthesis, comprising a blasting agent component, a carbon raw material that may be included as the blasting agent component, and diamond particles, An explosive composition for diamond synthesis, wherein the total proportion of the explosive component, the carbon raw material, and the diamond particles is 99 mass % or more based on the total amount of the explosive composition for diamond synthesis. [Appendix 2] An explosive composition for diamond synthesis as described in Appendix 1, wherein the crystallite diameter of the primary particles of the diamond particles measured by XRD method is 100 nm or less (preferably 50 nm or less, more preferably 10 nm or less, and even more preferably 7 nm or less). [Appendix 3] An explosive composition for diamond synthesis according to appendix 1 or 2, wherein the diamond particles include diamond clusters. [Appendix 4] An explosive composition for diamond synthesis according to any one of Appendices 1 to 3, wherein the diamond particles include detonation diamond particles (preferably air-cooled detonation diamond particles). [Appendix 5] An explosive composition for diamond synthesis according to any one of Appendices 1 to 4, wherein the explosive component comprises an explosive component that serves as the carbon raw material. [Appendix 6] An explosive composition for diamond synthesis as described in Appendix 5, wherein the explosive component that serves as the carbon raw material contains a compound having a nitro group (preferably a compound having three or more nitro groups, more preferably 2,4,6-trinitrotoluene). [Appendix 7] An explosive composition for diamond synthesis described in any one of Appendices 1 to 6, in which the diamond particles are contained in an amount of 15 parts by mass or less (preferably 10 parts by mass or less, more preferably 5 parts by mass or less) per 100 parts by mass of the total amount of the explosive components. [Appendix 8] An explosive composition for diamond synthesis described in any one of Appendices 1 to 7, wherein the diamond particles are contained in an amount of 0.05 parts by mass or more (preferably 0.08 parts by mass or more) per 100 parts by mass of the total amount of the explosive components. [Appendix 9] An explosive composition for diamond synthesis according to any one of Appendices 1 to 8, wherein the explosive component comprises 2,4,6-trinitrotoluene and cyclotrimethylenetrinitramine. [Appendix 10] An explosive composition for diamond synthesis according to Appendix 9, wherein the mass ratio [former / latter] of 2,4,6-trinitrotoluene to cyclotrimethylenetrinitramine in the explosive components is 30 / 70 to 95 / 5 (preferably 40 / 60 to 90 / 10, more preferably 51 / 49 to 80 / 20, and even more preferably 55 / 45 to 70 / 30).

[0077] [Appendix 11] An explosive composition for diamond synthesis according to any one of Appendices 1 to 10, wherein the content of the explosive component in the explosive composition is 60% by mass or more (preferably 70% by mass or more, more preferably 90% by mass or more) relative to the total amount of the explosive composition. [Appendix 12] An explosive composition for diamond synthesis according to any one of Appendices 1 to 11, wherein the total proportion of the explosive components, the carbon raw material, and the diamond particles in the explosive composition is 99.5 mass% or more (preferably 99.8 mass% or more) relative to the total amount of the explosive composition.

[0078] [Appendix 13] An explosive composition for diamond synthesis, comprising an explosive component, a carbon raw material which may be contained as the explosive component, and an adamantane, the explosive components include 2,4,6-trinitrotoluene and cyclotrimethylenetrinitramine; An explosive composition for diamond synthesis, wherein the mass ratio [former / latter] of 2,4,6-trinitrotoluene to cyclotrimethylenetrinitramine in the explosive component is 30 / 70 to 95 / 5 (preferably 40 / 60 to 90 / 10, more preferably 51 / 49 to 80 / 20, and even more preferably 55 / 45 to 70 / 30). [Appendix 14] An explosive composition for diamond synthesis as described in Appendix 13, wherein the total proportion of the explosive component, the carbon raw material, and the adamantanes is 99 mass% or more relative to the total amount of the explosive composition for diamond synthesis. [Appendix 15] An explosive body for diamond synthesis, which is a compressed product of the explosive composition for diamond synthesis according to any one of Appendices 1 to 14. [Appendix 16] An explosive body for diamond synthesis, which is a compressed explosive composition containing an explosive component, a carbon raw material which may be contained as the explosive component, and nanodiamond particles. [Appendix 17] An explosive body for diamond synthesis, which is a compressed explosive composition containing an explosive component, a carbon raw material which may be contained as the explosive component, and an adamantane. [Appendix 18] A method for producing diamond particles, comprising a detonation step of detonating an explosive component in an explosive body for diamond synthesis described in any one of Appendices 15 to 17 to obtain diamond particles with a diameter larger than that obtained when the diamond particles or adamantanes, which are seed crystals, are not blended. [Appendix 19] A method for producing diamond particles according to Appendix 18, wherein the diamond particles obtained in the detonation step include single crystal diamonds.

Claims

1. An explosive composition for diamond synthesis, comprising an explosive component containing a carbon raw material and diamond particles, The explosive composition for diamond synthesis may contain the explosive component and a carbon raw material other than the diamond particles, An explosive composition for diamond synthesis, in which the total proportion of the explosive component and the diamond particles (however, in the case where the explosive composition for diamond synthesis contains the explosive component and a carbon raw material other than the diamond particles, the total proportion of the explosive component, the diamond particles, and the explosive component and a carbon raw material other than the diamond particles) is 99 mass% or more relative to the total amount of the explosive composition for diamond synthesis.

2. 2. The explosive composition for diamond synthesis according to claim 1, wherein the crystallite size of the primary particles of said diamond particles measured by XRD method is 100 nm or less.

3. 3. An explosive composition for diamond synthesis according to claim 1, wherein the diamond particles include diamond clusters.

4. 4. The explosive composition for diamond synthesis according to claim 1, wherein the diamond particles include detonation diamond particles.

5. 5. The explosive composition for diamond synthesis according to claim 1, wherein the explosive component comprises a compound having a nitro group.

6. 6. An explosive composition for diamond synthesis according to claim 1, wherein the diamond particles are contained in an amount of 15 parts by mass or less per 100 parts by mass of the total amount of the explosive components.

7. 7. The explosive composition for diamond synthesis according to claim 1, wherein the explosive component comprises 2,4,6-trinitrotoluene and cyclotrimethylenetrinitramine.

8. 8. The explosive composition for diamond synthesis according to claim 7, wherein the mass ratio of 2,4,6-trinitrotoluene to cyclotrimethylenetrinitramine [former / latter] in said explosive component is 30 / 70 to 95 / 5.

9. An explosive body for diamond synthesis, which is a compressed product of the explosive composition for diamond synthesis according to any one of claims 1 to 8.

10. A compressed explosive composition containing an explosive component including a carbon raw material and an adamantane, The explosive composition may contain the explosive component and a carbon raw material other than the adamantanes.

11. A method for producing diamond particles, comprising a detonation step of exploding the explosive components in the explosive body for diamond synthesis described in claim 9 to obtain diamond particles with a larger diameter than the diamond particles obtained when the diamond particles as seed crystals are not blended.

12. A method for producing diamond particles, comprising a detonation step of detonating the explosive component in the diamond synthesis explosive body described in claim 10 to obtain diamond particles with a larger diameter than those obtained when the adamantane seed crystals are not blended.

13. The method for producing diamond particles according to claim 11, wherein the diamond particles obtained in the detonation step comprise single crystal diamond.

14. The method for producing diamond particles according to claim 12, wherein the diamond particles obtained in the detonation step comprise single crystal diamond.

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