TW200920698A - Process for preparing metal oxide granules - Google Patents

Abstract

Process for preparing metal oxide granules having a particle diameter of 200 to 1500 μm, characterized in that a pyrogenic metal oxide powder selected from the group consisting of the oxides of Al, B, Ce, Cs, Er, Fe, In, Ga, Ge, Ni, Pb, Sn, Ta, Zr and/or Zn with a tamped density of 10 to 1200 g/l is compacted to slugs which are subsequently crushed and optionally classified, the slug fragments having a tamped density of 210 to 2000 g/l.

Description

200920698 IX. Description of the Invention [Technical Field of the Invention] The present invention relates to a method of preparing metal oxide particles and the particles themselves. [Prior Art] There are known a myriad of methods for preparing metal oxide particles. Suitable starting materials may be metal oxides prepared by a sol-gel process, metal oxides obtained by deposition or fumed metal oxides. This method of manufacture typically involves wet granulation. In this method, a sol is obtained from a colloidal metal oxide dispersion by continuous mixing or stirring, and a friable material thus obtained by gradually removing moisture. The preparation by wet granulation is complicated and expensive, especially when the low contamination of the granules is highly demanded. Incidentally, the metal oxide can be obtained by spray-drying the dispersion. For example, WO-A-03/0 14021 and EP-A-1 266864 disclose particles of alumina or alumina-doped ceria having an average particle size of 10 to 150 μηη and 400 to 1 200 g. /ΙThe mounting density. A disadvantage of the disclosed method is that the (surface) nature of the powder actually used can be altered by treatment in a liquid medium. Moreover, these methods do not allow the preparation of particles having a particle size greater than 150 μηη. Fluidity and dust damage are improved compared to ungranulated powders, but nevertheless are still of interest for further optimization of these parameters. 附带 In addition, particles can be obtained by compacting metal oxides. No adhesive -5- 200920698 Pressing the pyrolysis metal oxide is difficult because the fumed metal oxide is very dry and has no capillary forces to bond the particles. Pyrolysis of metal oxides 得 Note that very fine, low bulk density, high specific surface area, high purity, very substantial spherical original particle shape and no pores. Pyrolytic metal oxides often have a high surface charge which complicates agglomeration in terms of static electricity. The compaction of pyrogenic metal oxides has not yet been made available for the preparation of high-priced niobium particles. It is an object of the present invention to provide a method of preparing metal oxide particles without the need for a binder. This method allows a large amount of preparation and provides a product having high purity, which incidentally has high fluidity and low dust (dust nuisance). The present invention provides a metal oxide having a particle diameter of 200 to 1 500 μm. a method of particle granules characterized by having a density of 10 to 1200 g/1 selected from the group consisting of Al, B, Ce, Cs, Er, Fe, In, Ga, Ge, Ni, Pb, Sn, Ta, Zr and The pyrolysis metal oxide compound powder of the group consisting of Zn is compressed into agglomerates, after which the agglomerates are crushed and classified as needed, and the agglomerate fragments have 210 to 2 g/ The mounting density of the crucibles depends on the type of metal oxide powder. In principle, with regard to the method according to the invention, the densit density of any metal oxide powder is lower than that of the agglomerates produced. The pyrolysis metal oxide powder preferably has a BET surface area of from 10 to 500 m 2 /g, and more preferably from 30 to 150 m 2 /g ° 200920698. The fumed metal oxide powder used may preferably be a fumed alumina. Powder. The pyrogenic alumina powder preferably has a capacity of from 1 〇 to 18 〇 g/i. Further, it preferably has a BET surface area of 30 to 150 m2/g. The pyrolytic metal oxide powder used may also be a mixed oxide powder or a doped metal oxide powder. The dopant component may be one or more oxides selected from the group consisting of Ca, K, Li, Mn, Na, P, Si, T i or Y. According to the invention, the mixed oxide powder means the mixed oxide The content of the component is 3 to 50% by weight based on the mixed oxide powder. The content of the dopant component is 10 ppm to 3% by weight based on the metal oxide powder of the doped metal oxide powder. In the invention, it is regarded as a metal. The mixed oxide powder preferably has a mixed oxide component, and the doped metal oxide powder preferably has a dopant component. The mixed oxide powder and the doped metal oxide powder are metal. The oxide has a bond between the mixed oxide component or the dopant component, such as Si-0-Al or Si-0-Ti. Preferably, a pyrolytic yttrium-aluminum mixed oxide powder can be used. Sand weight is better 7: 30 to 90: 10 Preferably, a pyrolytic cerium-zirconium mixed oxide powder can also be used. The weight of the |B/ 比较 is preferably 8 5 : 15 to 9 5 : 5. With a density of 10 to 1 200 g/Ι. The pyrolyzed metal oxide powder is compressed into agglomerates. The agglomerates represent some strips of intermediates caused by the gentle pressurization of the starting material. The intermediates are crushed in the second step. The properties of the agglomerates and agglomerate fragments are subject to the control mode selected in 200920698, the compression force, the gap width between the two rolls, and the dwell time established by the corresponding change in the pressurizing light speed ( Pressure hold time) The influence of the program parameters. The pyrogenic metal oxide powder used has a packing density of 10 to 1 200 g/inch. Preferably, a pyrolytic metal oxide powder having a mounting density of 15 to 600 g/inch is used, more preferably 20 to 400 g/inch, and most preferably 40 to 20 0 g/inch. The mounting density specified in the present invention is determined in accordance with DIN EN I S Ο 7 8 7 - 1 1 . The density of the fumed metal oxide powder can be compacted to these crucibles by conventional methods and apparatus. For example, a device according to US43 2 5 6 86 , US 4877595, US 3 8 3 8 7 8 5 , US 3 7425 66 , US 3762851, US 3862682 can be used. In a preferred embodiment of the invention, a pyrolyzed metal oxide powder compacted by a pressing belt filter according to EP-A-02 8085 1 or US 4,877,595 can be used. Thereafter, the pyrolyzed metal oxide powder having a density of 15 to 1200 g/1 is compacted into agglomerates. It is understood that compression means mechanical compression without the addition of adhesive. In order to obtain agglomerates having a very substantial uniform density, the compaction should ensure simultaneous pressurization of the fumed metal oxide powder. Pressing into agglomerates can be initiated by two rolls, one or both of which can have an exhaust function at the same time. Preferably, two compaction rolls can be used, which can be smooth or profiled. The shape can optionally be on only one compaction roller or two compaction rollers. The profile may be formed by a shaft parallel groove or a recessed (concave) configuration of any structure. In a further embodiment of the invention, at least one of the rolls -8 - 200920698 can be a vacuum roll. In order to compress, a suitable method is, in particular, pressing the pyrolysis metal oxide powder to be compacted by two compacting rolls. At least one of the two compacting lights is configured to be driven in rotation and has a belt At a specific pressure of about 0.5 kN/cm to 50 kN/cm, the surface of the compaction rolls is composed of a material that is mainly or completely free of metals and/or metal compounds' or the surface is made of a very hard material. Composition. Suitable materials are industrial ceramics such as tantalum carbide, niobium nitride, coated metal or alumina. This method is suitable for minimizing contamination of the agglomerate fragments and the metal oxide particles. After compaction, the agglomerates are crushed. Finally, a screen granulator that defines the particle size with the mesh width of the screen can be used. The mesh width can be from 250 μηι to 20 mm. The agglomerate fragments have a mounting density of 210 to 2000 g/inch. A specific example in which the agglomerate fragments have a mounting density of 280 to 1500 g/inch is preferred. Particularly preferred are specific examples in which the agglomerate fragments have a mounting density of 400 to 1000 g/inch. The agglomerate fragments generally have a 10 to 40% higher packing density than the uncrushed agglomerates. The agglomerate fragments can be substantially classified by a flow screen, screen or air sorter. The agglomerate fragments have a particle size of 200 to 15 μm by a sieve analysis. Preferably, the particle size may be from 300 to 700 μηη. The fine fraction (particles smaller than 200 μm) can be removed. The air sorter used may be a crossflow classifier, a countercurrent deflection classifier, and the like. The air separator used in 200920698 can be a cyclone. The fine fraction (particles smaller than 200 μηι) removed during classification can be recycled to the procedure according to the invention. The graded agglomerate fragments can thereafter be exposed to an environment comprising one or more reactive compounds suitable for removing hydroxyl groups and impurities from the agglomerate fragments at a temperature of 400 to 1 1 Torr (the temperature may be Chlorine, hydrochloric acid, sulfur halides and/or oxyhalogenated sulphur. More preferably, chlorine, hydrochloric acid, disulphur dichloride or sulfite dichloride may be used. Usually, such reactivity The compound is used in combination with air, oxygen, helium, nitrogen, argon and/or carbon dioxide. The proportion of the reactive compounds may be from 0.5 to 20 volumes 〇/〇. Thereafter, depending on the composition of the agglomerates, Sintering at 1 2 0 0 °c to 1700 ° C. The present invention further provides metal oxide particles obtainable by the method of the present invention. The sum of impurities in the metal oxide particles of the present invention may preferably be <50 The sum of the impurities may preferably be less than 1 〇 ppm and more preferably less than 5 ppm. The proportion of the metal impurities may preferably be < 5 ppm and more preferably < 1 ppm ° The following impurity content particles are all expressed in ppb: A1 < 600, Ca < 300, Cr < 2 5 0 'Cu < 10, Fe < 800, K < 80 > Li < 1 0 'Mg < 20 ' Μη < 20 ' Na < 80 > Ni < 800 ' Ti < 200, VS 5 and Zr S 80. The difference between the impurity and the dopant composition should be described. The dopant component is a substance deliberately added to the raw material. The impurity is present in the raw material from the beginning. Substance or inadvertently added during treatment - October 20, 2009,698. Very good can be particles with the following impurity content, all expressed in ppb: A1 < 3 5 0 ' Ca < 90 ' Cr < 40 > Cu < 3 ' Fe < 100, K < 50 ' Li < 1 ' Mg < 10 ' Μη < 5 ' N a < 5 Ο ' N i < 8 0 ' Ti < 100' V &lt 1 , Zr < 3. The metal content is determined by inductively coupled plasma mass spectrometry (ICP-MS) with an accuracy of nearly 10%. In particular, favorable metal oxide particles may have a temperature of 2 1 0 to Alumina particles having an average particle diameter of 600 μm and a density of 280 to 550 g/Ι. The present invention further provides the metal oxide particles for use in the manufacture of ceramic materials, composite materials, catalysts and contacts. The use of the media carrier. [Embodiment] Embodiments The examples were carried out in accordance with the following procedures. The raw materials, reaction conditions and device settings are reproduced in Table 1. The metal oxide powder used was prepared by pyrolysis. The powder of Example 1 corresponds to the one disclosed in Example 1 of EP-A-1 083 151. The powder of Example 2 corresponds to the one disclosed in Example 1 of EP-A-5 85 544. The powder of Example 3 corresponds to the one disclosed in Example 1 of DE-A-1 0200406 1 702. The powder of Example 4 corresponds to the one disclosed in Example 1 of DE-A-102004039139. The resulting rod-shaped agglomerates were crushed by a masher (Frewitt MG-633) equipped with a screen fabric (-11 - 200920698 size 800 μm). After the removal of the fines, stable agglomerate fragments are obtained. Thereafter, the agglomerate fragments were purified in the HC1 gas stream of the reactor. In each case, high purity metal oxide particles and the sizes and impurities listed in Table 1 were obtained. The metal oxide particles of the invention are very pure. It does not contain a binder. The dust content is significantly lower than the powder used. The metal oxide particles have the necessary cohesive force in order not to decompose prematurely in subsequent steps of the application. Nonetheless, the metal oxide particles still exhibit good bonding properties. -12- 200920698 Table 1: Raw materials, reaction conditions and equipment setting Example 1 2 3 4 Metal oxide powder BET surface area m2/g 121 58 62 47 Composition 1 Al2〇3 Al2〇3 T1O2 Zr02 Content wt% - 71.2 91.9 94.6 Ingredient 2 - Si02 Zr02 Y2〇3 Content wt% - 28.8 7.9 5.4 Mounting density g/l 63 76 93 120 Compactor 1 Pressurizing force kN 10-20 30-40 10-20 10-20 Roller speed min 4 3 4 4 Screw speed min 80 80 80 80 Agglomeration / agglomeration debris density agglomeration 2 g / l 360 390 700 780 agglomerate fragments 3 g / l 450 510 750 850 purification (HC1) temperature °c 850 900 800 80 time min 60 60 60 30 average particle diameter 4 μιη 240 380 510 670 impurity Li ppb < 0.1 < 0.1 < 0.1 < 0.1 B ppb < 0.1 < 0.1 < 0.1 < 0.1 Na ppb < 0.1 <0.1 < 0.1 < 0.1 < 0.1 Mg ppb < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 A1 ppb - - 0.62 0.43 Ca ppb 0.17 0.12 0.32 0.24 Τΐ ppb - - - Cr ppb 0.48 0.64 0.86 0.33 Mn ppb < 0.1 <0.1 <0.1 <0.1 Fe ppb 0.86 0.61 0.64 0.53 Ni ppb 0.42 0.32 0.21 0.31 Cu ppb 0.16 <0.1 0.11 <0.1 Zr ppb 0.30 <0.1 - - K ppb <0.1 <0.1 <0.1 <0.1 Sintered particle sintering temperature °C 1460 1410 1320 1380 BET surface area m2/g <1 <1 <;1<1 1 ) Compactor: L 2 00/5 0 P from Hosokawa BEPEX GmbH ; Machining width: 50 mm; pre-vented; equipped with 12 mm hardened steel roll with wavy profile, side Closed; 2) before grading; 3) after grading; 4) sieved-13 -

Claims (1)

200920698 X. Patent Application No. 1. A method for preparing metal oxide particles having a particle diameter of 200 to 1 500 μm, characterized by having a density of 10 to 1 200 g/Ι selected from Al, B, Ce a pyrolysis metal oxide powder of a group consisting of oxides of Cs, Er, Fe, In, Ga, Ge, Ni, Pb, Sn, Ta, Zr and/or Zn is pressed into agglomerates, followed by agglomeration The agglomerates are crushed and graded as needed. The agglomerate fragments have a packing density of 2 1 2000 to 2000 g/Ι. 2. The method of claim 1, wherein the pyrolytic metal oxide powder used has a BET surface area of from 10 to 500 m2/g. 3 _ The method of claim 1 or 2, which uses a pyrolyzed alumina powder. 4. The method of claim 3, wherein the pyrolytic aluminum oxide powder has a mounting density of 10 to 180 g/inch. 5. The method of claim 3, wherein the pyrolytic aluminum oxide powder has a BET surface area of 30 to 150 m2/g. 6. The method of claim 1 or 2, wherein the pyrolyzed mixed oxide powder or the pyrogenically doped metal oxide powder is used, the pyrolyzed mixed oxide powder or the pyrolytic doped metal oxide powder comprises One or more oxides selected from the group consisting of Ca, K, Li, Mn, Na, yttrium, Si, Ti or lanthanum. 7. The method of claim 1 or 2, wherein the agglomerate fragments are treated with one or more reactive compounds at 400 ° C to n ° ° C. 8. The method of claim 1 or 2, wherein the fragments are frozen after being treated with the reactive compounds. 9--A metal oxide particle obtainable by the method of claim 1 of the patent application. 10. The metal oxide particles according to claim 9 wherein the proportion of metal impurities is less than 50 ppm. 1 1 A metal oxide particle as claimed in claim 9 or 1 which is an alumina particle having an average particle diameter of 210 to 600 μηη and a packing density of 280 to 550 g/Ι. 1 2 - A use of a metal oxide particle as claimed in claim 9 for the manufacture of a ceramic material, a composite material, and a catalyst carrier. -15- 200920698 七无明说单单单号表为代图表表代定图表:案代图本本表' '代定一二bar ✓iv fx 无八, if there is a chemical formula in this case, please Reveal the chemical formula that best shows the characteristics of the invention: none