Precursor for preparing inorganic powder and method for preparing inorganic powder

Abstract

According to an aspect of the present invention, provided is a method for preparing an inorganic powder. The method for preparing an inorganic powder may comprise the steps of: (a) introducing a solid metal chloride-metal oxide composite into a chemical vapor synthesis reactor; (b) selectively vaporizing the metal chloride in the metal chloride-metal oxide composite introduced into the reactor, and collecting the unvaporized solid metal oxide; and (c) reacting the vaporized metal chloride with a reaction gas to produce an inorganic powder.

Description

Precursor for manufacturing inorganic powder and method for manufacturing inorganic powder

[0001] The present invention relates to a method for manufacturing inorganic powder, and more particularly to a method for manufacturing inorganic powder using a solid composite of a mixture of a metal chloride and a metal oxide as a precursor.

[0002] The present invention relates to Project No. UR240069, which was carried out with funding from the Ministry of Science and ICT and support from the Korea Institute of Materials Science.

[0003] Inorganic powder is a powder containing metal powder and ceramic powder, and is widely used as a filler for various electrical components (e.g., MLCC) or semiconductor heat dissipation materials. Metal powder includes nickel powder, copper powder, etc., and ceramic powder includes alumina powder, zirconia powder, alumina nitride powder, etc.

[0004] These inorganic powders can be manufactured by wet methods utilizing reactions in solution and dry methods utilizing gas-phase reactions. Dry methods include chemical vapor synthesis. Chemical vapor synthesis can use solid raw materials as precursors. In this case, the solid precursor is vaporized, and then powder can be produced through a gas-phase reaction with a reaction gas (e.g., hydrogen gas) in the gaseous state. Metal chlorides are widely used as precursors in chemical vapor synthesis. For example, NiCl2 is used as a precursor for nickel powder, and CuCl2 can be used as a precursor for copper. In the case of metal chlorides, the metal powder is produced by vaporizing them within a reactor and then reacting with hydrogen gas. For example, in the case of nickel powder, solid NiCl2 is vaporized within a reactor and then reacted with hydrogen gas to produce nickel powder.

[0005] Metal chlorides often react readily with moisture to form hydrates; therefore, when using metal chlorides as precursors, they may be used in a hydrated state. When hydrated metal chlorides are used as precursors in chemical vapor synthesis, the metal hydrates contained within the metal chlorides may form metal oxides as byproducts during the reaction within the reactor. In particular, the formed metal oxides accumulate at the reactor inlet, leading to continuous deposition. This can cause the reactor inlet to become clogged due to the deposited metal oxides. To prevent this problem, the metal chlorides used as precursors must be specially managed to prevent contact with moisture. For example, in the case of NiCl2, the moisture content must be managed to be 2% or less by volume.

[0006] As an example of such a management method, a process is known in which hydrated NiCl2 is converted into an anhydrate form by heat treatment in an SOCl2 atmosphere. However, this process has the problem of increased treatment costs due to reasons such as the prevention of safety accidents caused by the toxic gas SOCl2.

[0007] The technical problem that the technical concept of the present invention aims to solve is to provide a method for solving problems that arise when hydrated metal chlorides are used as precursors in chemical vapor synthesis. However, this problem is exemplary, and the technical concept of the present invention is not limited thereto.

[0008] According to one aspect of the present invention, a method for manufacturing inorganic powder is provided.

[0009] The method for manufacturing the above-mentioned inorganic powder may include: (a) a step of introducing a solid-phase metal chloride-metal oxide composite into a chemical vapor synthesis reactor; (b) a step of selectively vaporizing the metal chloride among the metal chloride-metal oxide composite introduced into the reactor and collecting the solid-phase metal oxide that is not vaporized; and (c) a step of reacting the vaporized metal chloride with a reaction gas to produce inorganic powder.

[0010] According to one embodiment of the present invention, the metal chloride-metal oxide composite may be obtained by heat-treating a hydrated metal chloride.

[0011] According to one embodiment of the present invention, step (b) may include a step of capturing unvaporized metal oxide among the composite.

[0012] According to another aspect of the present invention, a method for preparing a precursor for chemical vapor synthesis for the production of inorganic powder may comprise: (a) preparing a metal chloride in which at least a portion of the region is hydrated; and (b) heating the hydrated metal chloride to remove the hydrated region and forming a metal oxide in a portion of the region of the metal chloride to produce a metal chloride-metal oxide composite.

[0013] According to one embodiment of the present invention, a method for manufacturing inorganic powder may include: a step of introducing a solid metal chloride-metal oxide complex into a reactor of a chemical vapor phase synthesis apparatus; a step of selectively vaporizing a metal chloride among the metal chloride-metal oxide complex introduced into the reactor; and a step of reacting the vaporized metal chloride with a reaction gas to produce inorganic powder.

[0014] According to one embodiment of the present invention, the metal chloride-metal oxide composite can be formed as the metal chloride reacts to form a metal oxide.

[0015] According to one embodiment of the present invention, the metal chloride-metal oxide composite can be formed by heat-treating the metal chloride so that the metal chloride reacts to form a metal oxide.

[0016] According to one embodiment of the present invention, the metal chloride-metal oxide composite can be formed by heat-treating a metal chloride containing moisture, thereby causing the metal chloride to react and form a metal oxide.

[0017] According to one embodiment of the present invention, the metal chloride-metal oxide composite can be formed by heat-treating a metal chloride containing moisture, wherein the moisture reacts with the metal constituting the metal chloride to form a metal oxide.

[0018] According to one embodiment of the present invention, the metal chloride-metal oxide composite can be formed by heat-treating a metal chloride containing moisture, so that after the moisture evaporates, the metal constituting the metal chloride reacts with the metal in a steam state to form a metal oxide.

[0019] According to one embodiment of the present invention, the metal chloride-metal oxide composite can be formed by heat-treating a hydrated metal chloride so that the hydrated metal chloride reacts to form a metal oxide.

[0020] According to one embodiment of the present invention, the metal chloride-metal oxide composite can be formed by heat-treating a hydrated metal chloride, wherein the moisture removed from the hydrated metal chloride reacts with the metal constituting the metal chloride to form a metal oxide.

[0021] The above metal chloride-metal oxide composite can be formed by heat-treating a hydrated metal chloride, so that after the moisture removed from the hydrated metal chloride evaporates, it reacts with the metal constituting the metal chloride in a steam state to form a metal oxide.

[0022] According to one embodiment of the present invention, the metal chloride-metal oxide composite may have a metal oxide formed in a portion of the metal chloride.

[0023] According to one embodiment of the present invention, in the solid metal chloride-metal oxide composite, the solid metal oxide that has not vaporized can be collected in the metal oxide collection unit.

[0024] According to one embodiment of the present invention, in the solid metal chloride-metal oxide composite, the solid metal oxide that has not vaporized can be collected in a metal oxide collection unit located at a point where the metal oxide falls due to its own weight.

[0025] According to one embodiment of the present invention, the metal chloride in the metal chloride-metal oxide composite may include one or more of NiCl2, CoCl2, FeCl2, FeCl3, AlCl3, CuCl, and CuCl2.

[0026] According to one embodiment of the present invention, a method for manufacturing inorganic powder comprises: a step of introducing a solid nickel chloride-nickel oxide composite into a reactor of a chemical vapor phase synthesis apparatus; a step of selectively vaporizing nickel chloride among the nickel chloride-nickel oxide composite introduced into the reactor; and a step of reacting the vaporized nickel chloride with a reaction gas to produce inorganic powder; wherein the nickel chloride-nickel oxide composite may be formed by heat-treating hydrated nickel chloride so that the hydrated nickel chloride reacts to form nickel oxide.

[0027] According to one embodiment of the present invention, a method for preparing a precursor for manufacturing inorganic powder may comprise: a step of preparing a metal chloride in which at least a portion of the region is hydrated; and a step of heating the hydrated metal chloride to remove the hydrated region and forming a metal oxide in a portion of the region of the metal chloride to produce a metal chloride-metal oxide complex.

[0028] According to the technical concept of the present invention, by using a metal chloride-metal oxide complex obtained by heat-treating a hydrated metal chloride as a precursor for chemical vapor synthesis, problems that occur when using a hydrated metal chloride as a precursor can be prevented. The effects of the present invention described above are illustrative and the scope of the present invention is not limited by these effects.

[0029] Figure 1 shows a step-by-step method for manufacturing inorganic powder according to one embodiment of the present invention.

[0030] Figure 2 shows a vertical downward chemical vapor synthesis apparatus as an example of a reactor used to manufacture inorganic powder by chemical vapor synthesis.

[0031] FIG. 3 illustrates embodiments of a downward precursor supply unit following the technical concept of the present invention.

[0032] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The embodiments of the present invention are provided to more completely explain the technical concept of the present invention to those skilled in the art, and the following embodiments may be modified in various different forms, and the scope of the technical concept of the present invention is not limited to the following embodiments. Rather, these embodiments are provided to make the present disclosure more faithful and complete and to fully convey the technical concept of the present invention to those skilled in the art. In this specification, the same reference numerals denote the same elements throughout. Furthermore, various elements and areas in the drawings are depicted schematically. Accordingly, the technical concept of the present invention is not limited by the relative sizes or spacing depicted in the attached drawings.

[0033] According to the technical concept of the present invention, a metal chloride-metal oxide complex is used as a precursor for chemical vapor synthesis. The metal chloride-metal oxide complex can be obtained by heat-treating a metal chloride in which at least a portion of the region is hydrated.

[0034] When a metal chloride-metal oxide complex is introduced into a reactor as a precursor for chemical vapor synthesis, the metal chloride reacts with the reaction gas to produce metal powder, while the metal oxide remains without participating in the reaction. The remaining metal oxide falls due to gravity and is collected in a separate collection unit.

[0035] Figure 1 shows a step-by-step method for manufacturing inorganic powder according to one embodiment of the present invention.

[0036] Referring to FIG. 1, a step of introducing a solid metal chloride-metal oxide complex into a reactor is performed (S110).

[0037] A metal chloride-metal oxide complex serves as a precursor for chemical vapor synthesis for the production of inorganic powders. It is a complex composed of a metal chloride and a metal oxide, for example, in which the metal oxide is formed in at least a portion of the metal chloride. The metal chloride is a material used as a precursor in the chemical vapor synthesis process and may include one or more of NiCl2, CoCl2, FeCl2, FeCl3, AlCl3, CuCl, and CuCl2. The metal chloride may take various forms, such as particulates or pellets.

[0038] A metal chloride-metal oxide composite may be obtained by heating a metal chloride in which at least some regions are hydrated to remove said hydrated regions. For example, the steps of: (a) preparing a metal chloride in which at least some regions are hydrated; and (b) preparing a metal chloride-metal oxide composite by heating said hydrated metal chloride to remove the hydrated regions and forming a metal oxide in said regions of the metal chloride may be performed.

[0039] When hydrated metal chloride is heated, the water contained in the metal chloride evaporates and reacts with the metal constituting the metal chloride in a steam state to form metal oxides in some regions of the metal chloride.

[0040] For convenience, the method for manufacturing inorganic powder according to the present invention will be described below using nickel chloride (NiCl2) as an example of a metal chloride. This is illustrative and the present invention is not limited thereto.

[0041] For example, in the case of NiCl2 containing moisture (i.e., hydrated NiCl2), if heated above a temperature at which the moisture can be evaporated, the moisture evaporates and becomes water vapor (H2O(g)), and then solid NiO and HCl gas (HCl(g)) can be produced by the following reaction equation (1).

[0042]

[0043] Reaction Equation (1): NiCl2(s) + H2O(g) -> NiO(s) + 2HCl(g)

[0044]

[0045] The generated NiO is formed on the surface and / or internal regions of the NiCl2 particles to form a NiCl2-NiO complex.

[0046] Next, a step of vaporizing the metal chloride among the metal chloride-metal oxide complex introduced into the reactor is performed (S120). In this step, as only the metal chloride among the metal chloride-metal oxide complex is vaporized, the metal oxide remains in a solid state within the reactor. For example, in the case of a NiCl2-NiO complex, as NiCl2 is vaporized, NiO remains in particulate form. In this step, the metal oxide remaining in this manner is collected in a metal oxide collection unit separately provided within the reactor.

[0047] Next, a step (S130) is performed to produce an inorganic powder, such as a metal powder, by reacting the vaporized metal oxide with a reaction gas. For example, as in reaction equation 2, the vaporized NiCl2 reacts with hydrogen gas to form nickel powder and HCl.

[0048]

[0049] Reaction Equation (2): NiCl2(g) + H2(g) -> Ni(s) + 2HCl(g)

[0050]

[0051] According to the manufacturing method of the present invention, moisture contained in the precursor of the chemical vapor synthesis method is converted into a metal oxide through heat treatment to obtain a metal chloride-metal oxide complex, which is then used as a precursor for the chemical vapor synthesis method. The metal oxide present in the precursor is introduced into the reactor along with the metal chloride, and since it is a substance that does not participate in the reaction, it remains in the reactor in a solid state and is collected by a separate collection unit and is finally removed from the reactor after the chemical vapor synthesis process is completed.

[0052] According to the manufacturing method of the present invention, the moisture within the precursor is converted into an oxide form and anhydrous before being introduced into the reactor. Therefore, the phenomenon in which moisture contained in the precursor is heated and vaporized within the reactor, then reacts with the vaporized metal chloride to deposit as a metal oxide on the inner wall of the reactor, does not occur. Consequently, the problem that arises when moisture and metal chloride react inside the reactor to form a metal oxide as a reaction product can be fundamentally prevented.

[0053] FIG. 2 shows a vertical downward chemical vapor synthesis apparatus (600) as an example of a reactor used to manufacture inorganic powder by chemical vapor synthesis.

[0054] Referring to FIG. 2, the chemical vapor synthesis apparatus (600) includes a vertical reaction chamber (610) that extends in a hollow shape in the vertical direction. A heating unit (640) for heating the reaction chamber (610) is disposed on the outer surface of the reaction chamber (610). The heating unit (640) may be composed, for example, of a resistance heating element that is heated by electricity. The heating unit (640) may be divided into a plurality of heaters, and each heater may have its temperature controlled separately. For example, three heaters, such as heater 1, heater 2, and heater 3, may be disposed downwards. Each of the three heaters may be controlled to a separate temperature. Thus, by controlling the temperature of each heater, various temperature distributions can be implemented for different locations within the reaction chamber (610). For example, the upper and lower temperatures within the precursor supply unit (S) can be maintained differently. As another example, the temperature of the reaction unit can be implemented so that the temperature becomes lower as it moves downwards.

[0055] A precursor supply unit (S) that vaporizes a precursor and supplies it to a reaction unit is disposed at the upper part of the reaction chamber (610), and a reaction unit (R) in which gaseous precursors and reaction gases react with each other to form inorganic powder is disposed at the lower part of the precursor supply unit (S). The inorganic powder generated in the reaction unit (R) is collected in a collection unit (G) at the lower part of the reaction unit (R) and then undergoes a series of additional processes such as classification and powder washing.

[0056] A first supply unit (620) positioned at the top of the reaction chamber (610) supplies a precursor, which is a raw material, to a precursor supply unit (S) along with a carrier gas. As another example, if a precursor vaporization device is incorporated within the precursor supply unit (S), only the carrier gas for transporting the vaporized precursor may be introduced. Additionally, a separate flow path may be additionally formed in the first supply unit to supply additional quenching gas for cooling the partial precipitation area within the precursor supply unit. Since the precursor supply unit (S) is subject to vaporization of the precursor, it is necessary to maintain it at a high temperature above a certain temperature. Furthermore, since partial precipitation of the gaseous precursor must occur within the precursor supply unit (S), there may be localized areas with relatively lower temperatures. To this end, the temperature of the heating unit surrounding the precursor supply unit (S) can be appropriately controlled to maintain the temperature within the precursor supply unit at a locally different level.

[0057] The second supply unit (630) is a flow path into which a reaction gas that reacts with a gaseous precursor introduced from the precursor supply unit (S) to the reaction unit (R) is introduced, and is configured to directly supply the reaction gas to the reaction unit, and its shape or path is not specifically limited.

[0058] The precursor supply unit (S) vaporizes the precursor to form a gaseous precursor and discharges the gaseous precursor to the reaction unit (R). Accordingly, a flow path is formed within the precursor supply unit (S) through which the gaseous precursor can flow. As the precursor introduced through the first supply unit (620) is introduced into the precursor supply unit (S), it is vaporized to form a gaseous precursor. As another example, a separate precursor vaporization device may be placed within the precursor supply unit (S). In this case, the carrier gas introduced through the first supply unit (620) is mixed with the precursor vaporized by the precursor vaporization device, and the mixed gas is discharged from the precursor supply unit (S) and introduced into the reaction unit (R).

[0059] FIG. 3 illustrates embodiments of a downward precursor supply unit (700) following the technical concept of the present invention. Referring to FIG. 3, the flow path of the precursor supply unit (700) is configured to include one or more downward flow paths (710, 730) through which fluid flows downward and upward flow paths (720) through which fluid flows upward. The downward flow paths (710, 730) and the upward flow paths (720) are arranged adjacent to each other in parallel.

[0060] Specifically, a downward flow path (710), an upward flow path (720), and a downward flow path (730) are sequentially arranged adjacently from both sides of the precursor supply unit (700) in the direction of the central axis. The downward flow path (710) and the upward flow path (720) are symmetrical with respect to the central axis, and the downward flow path (730) is formed in the central part of the precursor supply unit (700) and has a configuration that extends along the central axis.

[0061] The flow path within the precursor supply section (700) is configured to pass sequentially through the downward flow path (710), the upward flow path (720), and the downward flow path (730) and then be discharged to the reaction section (R). The fluid flow is indicated by arrows in the drawing. The downward flow path (710) and the downward flow path (730) are areas where the introduced precursor vaporizes. A collection section (800) is disposed at the bottom of the downward flow path (710) and the downward flow path (730).

[0062] According to the technical concept of the present invention, the precursor introduced into the precursor supply unit (700) is a metal chloride-metal oxide composite. The metal chloride-metal oxide composite introduced into the precursor supply unit (700) falls due to its own weight and passes through the downward flow path (710). While passing through, the metal chloride in the metal chloride-metal oxide composite vaporizes, and the metal oxide remaining that does not vaporize falls due to its own weight and is collected in the bottom part of the collection unit (800).

[0063] Figure 3 illustrates the process of introducing a NiCl2-NiO complex as an exemplary precursor and capturing NiO. The complex labeled NiCl2-NiO in Figure 3 indicates that NiO is contained in a portion of NiCl2.

[0064] Referring to FIG. 3, the NiCl2-NiO composite is introduced into the precursor supply unit (700) and then falls along the downward flow path (710). The downward flow path (710) is maintained at a temperature range where NiCl2 can be vaporized but NiO is not. Therefore, NiCl2 is vaporized in the downward flow path (710) and the downward flow path (730), and the vaporized NiCl2 passes through the upward flow path (720) along the direction of the arrow (N), then passes through the downward flow path (730) again and flows into the reaction unit (R). The vaporized NiCl2 flowing into the reaction unit (R) reacts with hydrogen gas supplied through the second supply unit (630) to form nickel powder.

[0065] On the other hand, NiO that is not vaporized in the downward flow path (710) and remains in the form of particles continues to fall in the direction of the arrow (O) due to its own weight, and is finally collected in the collection section (800) located at the bottom of the downward flow path (710).

[0066] After the nickel powder synthesis process is completed, the NiO particles collected in the collection unit (800) are collected outside the precursor supply unit (700). The collected NiO can be discarded or utilized. In the case of recycling, the collected NiO can be converted back into NiCl2 particles by heat-treating it in a chlorine (Cl) atmosphere. The NiCl2 thus regenerated from NiO can be used again as a precursor for manufacturing nickel powder.

[0067] It will be obvious to those skilled in the art that the technical concept of the present invention described above is not limited to the aforementioned embodiments and attached drawings, and that various substitutions, modifications, and changes are possible within the scope of the technical concept of the present invention. Accordingly, the scope of rights of the present invention should be determined by the claims set forth below.

Claims

1. A step of introducing a solid metal chloride-metal oxide complex into the reactor of a chemical vapor phase synthesis apparatus; A step of selectively vaporizing the metal chloride among the metal chloride-metal oxide complex introduced into the reactor; and A step comprising reacting a vaporized metal chloride with a reaction gas to produce an inorganic powder; Method for manufacturing inorganic powder.

2. In Paragraph 1, The above metal chloride-metal oxide complex is, formed as metal chlorides react to form metal oxides, Method for manufacturing inorganic powder.

3. In Paragraph 1, The above metal chloride-metal oxide complex is, formed by heat-treating a metal chloride, wherein the metal chloride reacts to form a metal oxide, Method for manufacturing inorganic powder.

4. In Paragraph 1, The above metal chloride-metal oxide complex is, formed by heat-treating a metal chloride containing moisture, wherein the metal chloride reacts to form a metal oxide, Method for manufacturing inorganic powder.

5. In Paragraph 1, The above metal chloride-metal oxide complex is, formed by heat-treating a metal chloride containing moisture, wherein the moisture reacts with the metal constituting the metal chloride to form a metal oxide. Method for manufacturing inorganic powder.

6. In Paragraph 1, The above metal chloride-metal oxide complex is, formed by heat-treating a metal chloride containing moisture, and after the moisture evaporates, reacting with the metal constituting the metal chloride in a steam state to form a metal oxide, Method for manufacturing inorganic powder.

7. In Paragraph 1, The above metal chloride-metal oxide complex is, formed by heat-treating a hydrated metal chloride, wherein the hydrated metal chloride reacts to form a metal oxide, Method for manufacturing inorganic powder.

8. In Paragraph 1, The above metal chloride-metal oxide complex is, formed by heat-treating a hydrated metal chloride, wherein the moisture removed from the hydrated metal chloride reacts with the metal constituting the metal chloride to form a metal oxide. Method for manufacturing inorganic powder.

9. In Paragraph 1, The above metal chloride-metal oxide complex is, formed by heat-treating a hydrated metal chloride, wherein the moisture removed from the hydrated metal chloride evaporates and then reacts with the metal constituting the metal chloride in a steam state to form a metal oxide. Method for manufacturing inorganic powder.

10. In Paragraph 1, The above metal chloride-metal oxide complex is, Metal oxide formed in some areas of the metal chloride, Method for manufacturing inorganic powder.

11. In Paragraph 1, In the above-mentioned solid metal chloride-metal oxide complex, Unvaporized solid metal oxides are collected in the metal oxide collection unit, Method for manufacturing inorganic powder.

12. In Paragraph 1, In the above-mentioned solid metal chloride-metal oxide complex, The unvaporized solid metal oxide is collected in a metal oxide collection unit located at the point where the metal oxide falls due to its own weight. Method for manufacturing inorganic powder.

13. In Paragraph 1, In the above metal chloride-metal oxide complex, the metal chloride is, Comprising one or more of NiCl2, CoCl2, FeCl2, FeCl3, AlCl3, CuCl, and CuCl2, Method for manufacturing inorganic powder.

14. A step of introducing a solid nickel chloride-nickel oxide complex into the reactor of a chemical vapor synthesis apparatus; A step of selectively vaporizing the nickel chloride among the nickel chloride-nickel oxide composite introduced into the reactor; and The method includes the step of reacting vaporized nickel chloride with a reaction gas to produce inorganic powder; The nickel chloride-nickel oxide composite is formed by heat-treating hydrated nickel chloride, wherein the hydrated nickel chloride reacts to form nickel oxide. Method for manufacturing inorganic powder.

15. A method for manufacturing a precursor for chemical vapor phase synthesis for the production of inorganic powder, wherein A step of preparing a metal chloride in which at least some region is hydrated; and A step comprising: heating the hydrated metal chloride to remove the hydrated region and forming a metal oxide in a portion of the metal chloride to produce a metal chloride-metal oxide complex; Method for manufacturing a precursor for manufacturing inorganic powder.

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