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JP-7857281-B2 - Niobium nanoparticle preparation, use of the same preparation, and method for obtaining the same preparation

JP7857281B2JP 7857281 B2JP7857281 B2JP 7857281B2JP-7857281-B2

Inventors

  • カルドソ テイシェイラ デ アルブケルケ フォレイラ、セザル アウグスト
  • ボアレット、ジョエル
  • ダドリー クルス、ロビンソン カルロス

Assignees

  • フラス エーリエ ソシエダッド アノニマ

Dates

Publication Date
20260512
Application Date
20210817
Priority Date
20200817

Claims (17)

  1. A preparation of niobium pentoxide nanoparticles, characterized by containing 95 wt% or more of niobium pentoxide particles, wherein the particle size distribution profile is d10: 14 to 110 nm; d50: 29 to 243 nm; and d90: 89 to 747 nm. , preparation of the above niobium pentoxide nanoparticles.
  2. The nanoparticle preparation according to claim 1, characterized in that 90% to 99% of the particles (d90 to d99) are within a particle size range of 5 to 1000 nanometers (nm).
  3. A preparation of nanoparticles according to claim 1 or 2, characterized in that it contains niobium pentoxide particles with a content of 99 wt% or more.
  4. A nanoparticle preparation according to any one of claims 1 to 3 , characterized in that the particle size distribution profile is d10 70-100 nm; d50 170-240 nm; d90 400-580 nm.
  5. A nanoparticle preparation according to any one of claims 1 to 3 , characterized in that the particle size distribution profile is d50 10 to 178 nm; d80 10 to 300 nm; d90 10 to 400 nm.
  6. A nanoparticle preparation according to any one of claims 1 to 3 , characterized in that 90% to 99% of the particles (d90 to d99) are within a particle size range of 100 to 1000 nm.
  7. A nanoparticle preparation according to any one of claims 1 to 3 , characterized in that 90% to 99% of the particles (d90 to d99) are within a particle size range of 5 to 100 nm.
  8. The nanoparticle preparation according to claim 7 , characterized in that the particle size distribution profile is d10: 9 to 27 nm; d50: 16 to 67 nm; d90: 33 to 94 nm.
  9. A preparation of nanoparticles according to any one of claims 1 to 3 , characterized in that the average specific surface area is 0.5 to 150 m² /g.
  10. The nanoparticle preparation according to claim 9 , characterized in that the average specific surface area is 40 to 70 m² /g.
  11. - The step of supplying niobium pentoxide particles to a grinding device selected from a high-energy ball mill and a steam jet mill; - In a high-energy ball mill: the steps include: suspending the particles to be ground in a liquid at a particle concentration of 1 to 90% by mass relative to the mass of the particles and liquid, stabilizing the suspension until a stable colloidal suspension is obtained; placing the suspension and grinding balls having a selected diameter of 5 μm to 1.3 mm into the grinding chamber; adjusting the mill rotation speed between 500 and 4500 rpm; grinding the particles at a temperature below 60°C; or - In a steam jet mill: supplying particles less than 40 micrometers; adjusting the grinding conditions selected from either adjusting the speed of the air classifier between 1,000 and 25,000 rpm; adjusting the compressed steam pressure between 10 and 100 bar; and adjusting the temperature between 230 and 360°C; A method for obtaining niobium pentoxide nanoparticles, comprising the step of grinding the particles until a desired particle size distribution profile is obtained.
  12. The method according to claim 11, characterized in that the colloidal suspension is stabilized by adjusting the pH of a polar liquid medium to a range of 2 to 13 and optionally adding a surfactant, or by adding a surfactant to a non-polar liquid medium.
  13. The method according to claim 11 or 12 , further comprising a pre-grinding step of niobium pentoxide particles before the step of supplying them to a grinding device, characterized in that the pre-grinding is carried out until an average particle size of less than 40 micrometers is reached.
  14. The method according to claim 13 , characterized in that the preliminary grinding is performed in a ball mill, a disc mill, a high-energy mill, or a jet mill.
  15. - The step of supplying micrometer niobium pentoxide ( Nb₂O₅ ) particles to a high-energy ball mill; - A step of supplying liquid to the mill and adjusting the pH to a range of 5 to 10; - A step of supplying balls having a selected diameter of 50 μm to 400 μm to the mill; - The step of adjusting the mill rotation speed between 2000 and 4000 rpm; The method according to claim 11 or 12 , characterized by comprising the step of grinding the particles at a temperature of less than 60°C until a desired particle size profile is obtained.
  16. The method according to claim 11, characterized in that the high-energy ball mill is of the agitated medium type, the spheres are selected from zirconia, silicon carbide, and alumina , and the spheres are optionally stabilized with yttria, niobium pentoxide, or a combination thereof.
  17. The method according to claim 11 or 13 , characterized in that the steam jet mill is adjusted by the following parameters: rotation of an air classifier at 20,000 rpm; compressed vapor pressure at 50 bar; and superheated fluid temperature at 280°C.

Description

This invention relates to the fields of materials science and nanotechnology. More specifically, it describes the preparation of niobium nanoparticles, their use, and a method for obtaining them by grinding, i.e., by a top-down process. For decades, efforts to obtain large quantities of high-purity niobium pentoxide nanoparticles have failed, making this invention a previously considered impossible achievement. The nanoparticle preparations of this invention solve these and other problems, possessing unique composition, purity, particle size profile, and specific surface area, making them useful in a variety of applications. This invention also discloses a method for obtaining nanoparticles of niobium-containing mineral species by controlled grinding, without chemical reactions or contamination by agents specific to nanoparticle synthesis. In contrast to the latest technologies, this invention achieves large-scale production of high-purity niobium pentoxide nanoparticles, a predetermined particle size profile, and a very large specific surface area, enabling its practical application in several industrial applications. Particles of various materials, particularly ceramic materials including ceramic oxides, are extremely useful in a wide range of applications. In this field, so-called post-metallurgy is the focus of research by many research groups and companies involved in the development of specialty materials, and size limitations or particle size distribution profiles are crucial factors in the properties of such materials. Of particular importance in relation to the present invention is the emphasis on the difference between (i) a preparation containing a small amount of nanoparticles among other particles; (ii) a preparation containing particles mainly or entirely within the nanometer particle size range; and (iii) a preparation of nanoparticles mainly or entirely within the nanometer particle size range having a defined particle size distribution profile. The present invention provides two of these latter types. In this regard, a recent document by one of the inventors of the present invention (Powder Technology 383 (2021) 348-355 – Powder grinding and nano-particle sizing: sound, light and illumination) demonstrates how important it is to know about techniques for measuring particle size, especially for accurate descriptions of such sizes at the nanoscale. At the nanoscale, conventional measurement methods (EAS, electroacoustic spectroscopy, and DLS dynamic light scattering) are prone to errors when based on particle volume, and techniques based on the number of particles and their specific surface area are most appropriate at this dimension. While niobium particle preparations may ultimately contain small amounts of nanoparticles, the predominance of much larger particle sizes in the micrometer/micron range hinders the characterization of such preparations as actual nanoparticle preparations. Furthermore, the behavior of nanoscale materials is known to change significantly, and therefore, it is highly desirable to be able to obtain preparations containing niobium particles of high purity, primarily or entirely within the nanometer range, on a large scale without the contamination typical of the synthesis process. This invention solves these and other technical problems. Due to the unique properties of niobium, an element produced on a large scale in Brazil, ceramic oxides, particularly niobium pentoxide, have been explored for a variety of applications. Despite Brazil being one of the world's leading producers of niobium and the vigorous research activities surrounding this important material, decades of unsuccessful attempts have been made to obtain large-scale, high-purity preparations of niobium nanoparticles, primarily or entirely in the nanoparticle range. This invention solves these and other technical problems. The literature includes examples of methods for synthesizing niobium-containing nanoparticles using a method called bottom-up synthesis. However, because such methods are bottom-up or synthetic, they involve chemical reactions, agents, and products, and the resulting products typically contain a large amount of contaminants, including material residues or reaction by-products. Furthermore, nanoparticles obtained by bottom-up methods are limited to specific chemical species that are reaction products. Moreover, these methods are not technically and/or economically feasible on a large scale, which is partly why preparations of niobium nanoparticles with stable, pure, and primarily or entirely nanometer-range particle size distributions are not available on an industrial scale. This invention solves these and other technical problems. Methods for grinding/crushing/spraying transition metals typically aim to increase their specific surface area, enabling a variety of industrial applications. In the case of niobium or niobium-containing materials, particularly niobium pentoxide, known metho