DE4405202A1 - Process for producing spherical particles - Google Patents

Description

The present invention relates to a method for producing Position of spherical particles based on inorganic Oxi de, the particles obtainable by this process and their Use.

Spherical particles based on inorganic oxides, eg. B. based on silica, alumina, alumosili cat, magnesia, titania or zirconia are used in large scale as catalysts, catalyst support, adsorbent used, desiccant or ion exchanger. For the Most of the applications mentioned are particles with a uniform spherical shape and a narrow grain spectrum needed, so as uniform as possible packing and high Packing z. B. in the fixed bed reactor to allow. Become the particles used in the moving bed reactor, so is the Particles still expected an increased abrasion resistance. Should the Particles used as catalysts or catalyst support who that, they have to go beyond a narrow grain spectrum beyond that still a certain specific surface and specific Have pore volume.

Usually, spherical particles are based on inorganic oxides, for example based on silicon dioxide, alumina, aluminosilicates and / or other oxides obtained by the well-known sol-gel method. The Preparation of spherical silica particles is carried out according to this method, as z. B. in DE-AS 16 67 669 beschrie  ben is by reacting an aqueous solution of alkali metal silicates tes mixed with an aqueous solution of an acid. This gives a sol which is in drop-shaped particles is transferred, which subsequently in a so-called Form oil are made to gel. As a form of oil is doing to usually a water-immiscible liquid, eg. Eg mine oil, raw petroleum or kerosene. In another Process step is then subsequently a so-called bases exchange carried out in which the alkali metal content of he keep particles in an aqueous medium to less than 1 wt .-%, based on the dry substance is reduced. to closing the particles are then washed, dried and calcined. According to this method, the shape of the formed particles from the speed at which the Soltropfen fall through the mold oil, the sinks speed of sol drops of specific gravity and of the viscosity of the liquid used as a molding oil. According to another method known per se, the shaping The particles also take place by that after Zusam adding the alkali metal silicate solution to the aqueous acid solution obtained Soltropfen under the action of gravity dropping an air column, the drops during Fal to gel. After this method, gelling time and case must be height to be exactly matched. If not enough solidified drops are at risk of impact be deformed to the reaction liquid.

According to WO 92/07653 a sol-gel process is known, after the spherical particle based on alumina getting produced. Here are spherical drops of egg an alumina hydrosol by a vibrated Nozzle plate produced, which one by lateral blowing with Ammonia gas preconsolidated and then in an aqueous ammonia solution. In the production of larger particles Diameter of the particles is usually a foam layer, so that the impact of the particles on the ammonia solution is braked so as to prevent deformation or to prevent a breakup of the drops. The used  Aluminiumoxidsol or the alumina suspension should after This method has a certain viscosity in the range of 10 to 500 mPa at room temperature.

In US 2 652 371 a process for the production and Size classification of silica particles described in which sodium silicate sol drops at an oblique angle ver sprays, whereby one by blowing with an inert gas a porridge th ray of Soltropfen different sizes generated, the a size classification due to the different of the mass of the respective drops dependent flight widths made possible light. ("Cross-flow-procedure") Here only the drops get with the desired size access to the gelation effecting Reaction liquid, while the remaining Soltropfen over a collecting device for drop production attributed to who the. This requires avoidance of larger quantities of scrap, that the gelation of Soltropfen only in the reaction liquid so that even with this method the danger of Deformation on impact of not yet solidified particles is added to the reaction liquid.

According to US Pat. No. 3,558,508, a process for the production of Alumina balls known in which an acid Aluminiumoxidhy drat in a saturated with gaseous ammonia mixture Mineral oil and carbon tetrachloride is dropped. The hereby obtained particles have a wide distribution of pores diameter with a large proportion of macropores over 200 Å on.

There is thus still a need for a method after the spherical particle based on inorganic oxides after a sol-gel process with the best possible Kugelge stalt, a narrow grain spectrum and a narrow distribution of Pore diameter can be produced.

The object of the invention was therefore to provide a method for Her Position of spherical particles based on inorganic Oxi de to provide what the shape possible  uniformly spherical shaped particles with a narrow grain spectrum and narrow pore diameter distribution.

It has now become a process for producing spherical Particles based on inorganic oxides by sol-gel conversion found, in which a sol in a reaction gas enthal from the bottom sprayed so that the sol unmit before or until it enters the reaction zone individual Solperlen rips open and the formed Solperlen on one curved trajectory fly through the reaction zone, where they preconsolidated, and then the pre-consolidated Sol particle traps in a collecting device. By the The procedure according to the invention is the place and time of the Solperlenbildung on the beginning of gelation (pre-solidification) the sol beads matched in an advantageous manner. The sol pearls, at the time of their formation still liquid Soldropfen with almost ideal spherical shape and largely the same ball diameter are flowing through the reaction zone in their fixed almost ideal uniform spherical shape, d. H. vorverfe so that they largely ge before deformative effects ge are protected by further known measures of the Sol-gel method, the pre-solidified in their spherical sol finally solidified. For this purpose, the Injection device in a specific - by a specialist as below described, easy to determine - distance below the one outlet opening arranged in the reaction zone, wherein the distance at about that distance from the sprayer corresponds, in which the sol in Solperlen ruptures. additionally the sol is removed from the sprayer from below, i. H. opposite of gravity, at a certain angle α in the reac Sprayed zone, wherein angle α in this case from a horizon talen, perpendicular to the axis of gravity and the tangents te of the sprayed sol at the exit point from the spray system is formed.

According to the inventive method accordingly ge lierfähiges sol from bottom to top in the reaction zone, in special at an angle α <90 °, sprayed. As spraying  Depending on the particle size range, spraying can be used Needles of different diameters or per se known Spray nozzles, centrifugal discs, spray wheels, ultrasonic nozzles or bells, spray guns, turbo-bells, solenoid valves, mechanical powered nozzles or spray systems, as they are in the elek trostatic spraying or in jet printers (eg te nozzles) are used. The particle sizes rich is varied over the sprayer used. At a desired particle size in the range of 0.01 mm to 0.3 mm are therefore expediently turbo-bells, micro Mag net valves or spray nozzles, z. B. per se known spiral nozzles (For example, spray nozzles from Spraybest) or preferably Ultra sound nozzles used. For a desired particle size in Range of 0.3 mm to 5 mm, in particular 0.3 mm to 3.5 mm, it is expedient to use spray wheels or preferably canoes len corresponding diameter. At very small distance the Spraying device to the inlet opening of the reaction gas ent holding reaction zone, it may be appropriate, for. B. in the Using spray nozzles or small diameter cannulas, the spray device with a purge gas (eg compressed air or What steam), in order to prevent clogging of the spray direction by avoiding premature sols.

The inventive method is generally suitable for Preparation of particles which gelled by gelation solutions, d. H. made in a sol-gel reaction who you can. The sol can act as an unstable sol, which by Merging two components was obtained, or as meta stable sol, which ge only on contact with the reaction gas liert, present. In particular, the invention is suitable Process for the preparation of particles based on inorganic Oxides by sol-gel conversion. Inorganic oxides are included in particular the oxides from the group magnesium oxide, aluminum oxide, silica, aluminosilicate, zinc oxide, titanium dioxide, Chromium oxide, copper oxide, manganese oxide, cerium oxide, tin oxide, iron oxide, Nickel oxide, lead oxide, molybdenum oxide, vanadium oxide, thorium oxide, Zirconium oxide and / or hafnium oxide. Preferred oxides are Alu mosilikat, alumina and / or silica. The term  Inorganic oxide here comprises both the said metal oxides each by itself as well as mixed oxides, in particular binary or tertiary mixed oxides of which one component is silicon dioxide, alumina or aluminosilicate. Under inorgani oxides are also understood to mean oxides which, in addition to the gel-forming oxidic components further the application niche and / or catalytic properties improving additive ze included.

The inventive method can be used for the gelation of sols in which according to the sol-gel method, an unstable sol, z. B. by the mixing together of an alkaline component with an acidic component, is obtained. Preferably, particles based on silica or aluminosilicate are prepared by this procedure. So z. Example, a usable in the process according to the invention silicon dioxide-containing sol can be obtained by using as the alkaline cal component an aqueous solution of an alkali metal silicate, for. As a sodium silicate solution, with the aqueous solution of an inorganic acid, eg. As an aqueous solution of sulfuric acid or hydrochloric acid, or an organic acid, for. As an aqueous solution of formic acid or acetic acid mixed together in a conventional manner. Both the alkaline and the acidic component can be added to other ingredients, for example, aluminum or magnesium compounds. In another variant, a silicon dioxide containing tend unstable sol can be obtained by silicic acid alkyl ester with an alkaline component, eg. With NaOH, NH ₃ , or an acidic component, e.g. B. with hydrochloric acid, or silicon tetrachloride with an acidic component, eg. B. with aqueous formic acid. Another possibility for producing silica-containing particles which can be obtained in the process according to the invention consists in the use of metastable silica sol (eg Bayer S200®).

Sols can also be used in the process according to the invention be set which other components in homogeneous or contain heterogeneous form. As heterogeneous components can  they z. As fines of each known type, amount and Particle size included. To improve the application technology rule properties can z. B. as fines fillers be joined; z. B. fillers from the group of silicic acids, aluminum mosilikate, aluminas, titanium dioxide, kaolin, montmorillonite, Bentonite, zeolite, starch, wood flour or activated carbon. This filling Substances may be added to the acidic and / or alkaline component in kri stalliner or amorphous form or in highly dispersed form, as described in DE 42 16 868, are added. Also fines that the catalytic properties of the part chen change, can be used in a conventional manner who the. As homogeneous components can z. As magnesium, zirconium Be added copper, lead or titanium acetylacetonates.

Mixing of alkaline component with acidic Component to a gellable unstable sol can on known manner in any suitable Mischvorrich tion, z. B. a mixing nozzle, performed. Subsequently the sol thus obtained is immediately introduced into a spray device pumped, with it in the manner of the invention from below into the Reaction gas can be sprayed.

The inventive method can be used in particular for the production of spherical particles based on aluminum oxide. For this purpose, one uses per se known meta-stable acidic Aluminiumoxidhydratsole, which optionally further improve the performance properties de components contain. Suitable Aluminiumoxidhydratsole Kings nen according to the prior art of aluminum oxides, for. From alumina hydrate such as boehmite, pseudo-boehmite, hydrargillite or bayerite, by dispersing in aqueous acid, e.g. In nitric acid. It is also possible to be known manner from aluminum hydroxide and aluminum halides, for. As AlBr ₃ , AlCl ₃ , or metallic aluminum by the action of dilute acid, eg. As HCl, Aluminiumoxidhydratsole or dispersions used in the process according to the invention. The gelation of the sol can in this case be effected in different, per se known procedures or supported by the use of self-gelling sols. Thus, the Gelbil tion both chemically and physically, for. B. by pH change (to the acidic or alkaline), temperature change (He warm or cool) and, for example. Photochemical initiation triggered and supported.

In Fig. 1 the structure of a device for carrying out the method according to the invention is shown schematically by way of example. By a spray system, the gellable sol from bottom to top at an angle α <90 °, z. B. at an angle of 40 to 89 °, preferably 80 to 88 °, sprayed into the reaction zone so that the sol after leaving the spray system until immediately before or when passing the inlet into the reaction zone aufgeris sen in largely equal sol beads, wherein At the moment of their formation, the sol beads are practically immediately exposed to the gelling action of the reaction gas. The disintegration of the sol into individual sol beads depends not only on the angle, but also on the viscosity of the sol, the spraying device used in each case, and the pressure with which the sol leaves the spraying device. In order to adjust the point at which the sol tears into individual sol beads according to the invention, the distance d between spray device and inlet opening into the reaction zone at the beginning of the spraying process is varied by the expert by visual inspection, ie the distance d is reduced or possibly increased, until the tearing point of the sol in individual sol beads is located immediately before or in the inlet opening to the reaction zone.

After entering the reaction zone fly through the gebil Solperlen called a trajectory curved in the shape of a parabola by the reaction gas present in the reaction zone, being fixed in its spherical shape, d. H. be pre-consolidated. Because the sol beads pass through this parabolic trajectory must pass the reaction gas, the reaction gas after the method according to the invention for a particularly long time Vorverfesti contribute the sol pearls, so that thereby the danger of De Formation of the Solperlen when hitting the Auffangvorrich already largely minimized. By additional heating  men the reaction zone, z. B. by heating to about 200 ° C, can the preconsolidation of the particles optionally further un be supported. To further increase the risk of deformation may, if desired, be adjustable in height Catcher close to the reversal point of the parabolic Trajectory of Solperlen, where the Solperlen ki their smallest possessing netic energy, are brought up.

As a collecting device can in the process according to the invention a flat-drawn film, z. As a PVDF film or PE or PVC film or a smooth collecting tray or one with liquid filled collecting container can be used. When using egg This smooth collecting tray can be cooled as such or it may evenly cover with solid carbon dioxide tes sheet be used. Particularly preferred Verfahrensva variants use one with a liquid sity, eg B. with water or preferably with a reaction liquid filled container. Under reaction liquid In this case, all common acidic or alkaline liquids are used understood as they are usually used for the aging of Particles are used according to the sol-gel method. Gebräuch Liche reaction liquids are for this purpose z. B. aqueous ammonia solution, z. B. a 5 to 10% aqueous ammonia solution, or acidic reaction liquids such as hydrochloric acid, sulfuric acid or Nitric acid in concentrations of 1 to 5 wt .-%. When using tion of a reaction liquid should expediently in the Reaction zone used for this purpose equivalent reaction gases who the. If, as a reaction liquid z. B. an aqueous Ammonia solution before, so should ammonia gas as the reaction gas or vapors of organic amines. Using acidic reaction liquids such as hydrochloric acid, sulfuric acid or Nitric acid should have the equivalent acidic reaction gases, ie hydrogen chloride, sulfur dioxide or nitrogen oxides ver be used.

The reaction gas used in the process according to the invention can in the reaction zone as a closed container over the corresponding collecting device are kept light. Fri  nice reaction gas can constantly as needed by a be replenished separate gas supply in the reaction zone. ne ben the already mentioned alkaline or acidic reaction gases can react with self-gelling brine as a reaction gases also used inert gases such as air or nitrogen in which case, if appropriate, the preconsolidation of the sol Particles by heating the reaction zone to temperatures of up to 1000 ° C or higher, preferably 500 to 800 ° C, below can be supported. When using one evenly with solid carbon dioxide covered collecting tray as Auffangvorrich tion, the reaction zone may also be at temperatures be cooled below room temperature in order to do so by lowering the viscosity, the preconsolidation of the sol to support particles.

From the collecting device, the pre-consolidated sol Part of the workup, as is customary for after Sol-gel process particles are carried out, supplied be led. This work-up usually includes the up Processing steps Washing, drying and optionally calcining. So The sol particles are usually at temperatures in the range from 100 to 200 ° C for a period of 1 to 24 hours dries. In a variant, the pre-consolidated Solteil chen when using a flat-drawn film or a glat catch tray as a catcher also directly into a Drying unit, z. B. in a known spray skirt ner, be transferred.

For the production of particularly small particles, in particular of particles with a diameter in the range of 0.001 mm to 0.3 mm, in a modification of the method according to the invention expediently a device is used, as shown schematically in Fig. 2. This device differs from that shown in Fig. 1 in that very small sol beads are sprayed as mist from below into the reaction zone. In this process variant, the small sol beads are produced as a mist through a nozzle, expediently a spiral nozzle or preferably an ultrasonic nozzle, which then according to the invention from bottom to top, z. B. with a known from ventilation systems wing fan, in which the reac tion gas-containing reaction zone are sprayed. The further steps are then carried out analogously to the process steps as already described above for the procedure described in FIG. 1 for larger particles.

In a further embodiment of this process, the spherical particles obtained according to the invention above can still be subjected to a treatment with a lower alkyl alcohol, in particular a C ₁ -C ₄ -alcohol, such as. As methanol, ethanol, propanol or isopropanol, or a treatment with acetone, before they are fed after catching in the catcher of the drying. Isopropanol, which should be as free of anhydrous as possible, is preferably used for this treatment. By the treatment with a lower alkyl alcohol or acetone, on the one hand, adhesion of the obtained particles, in particular of particles having an average diameter smaller than 1 mm, can be avoided on drying, on the other hand, by this treatment, the pore volume of the obtained particles be widened. For this purpose, the particles are transferred from the capture device to a container and overlaid several times with alcohol for a period of time from 1 minute to 24 hours, advantageously 2 to 3 hours. So z. B. by this treatment, the pore volume and alumina particles are selectively changed. So is z. Example, the pore volume of aluminum oxide particles prepared by the process according to the invention after treatment with a lower alkyl alcohol in the range of 0.4 to 2.5 ml / g (determined after drying).

By the method according to the invention, it is in vorteilhaf ter way possible, particles based on inorganic oxides with a very uniform spherical shape, a narrow distribution pore diameter and a very narrow particle size range receive. Here, the accumulation of larger amounts of sub- Oversize grain are largely avoided. Under a tight grain spectrum is understood to mean a grain spectrum in which 80% of the  Particles have a diameter within the following Table specified range around the respective average through have a knife (Gaussian distribution).

In the process according to the invention no mold oil needs to be set so that the particles thus produced free from further impurities or discoloration. Also can be in the case of particles produced by the process according to the invention by treatment with acetone or a lower alkyl alcohol Get the pore volume in an advantageous manner before drying expand. In addition, the show according to the invention Process produced spherical particles a surprising high abrasion resistance.

Furthermore, the invention comprises spherical particles Base of inorganic oxides, preferably based on silicon dioxide, alumina or aluminosilicate, which

• a) a diameter in the range of 0.01 to 5 mm, preferably 0.02 to 3.5 mm,
• b) a specific surface area in the range of 1 to 900 m ² / g, preferably 100 to 800 m ² / g,
• c) a bulk density in the range of 0.1 to 1.0 g / ml,
• d) a pore volume in the range of 0.25 to 2.5 ml / g,
• e) a distribution of pore diameters with a maximum (mo nomodal pore distribution) in the range of 15 to 2000 Å preferably 15 to 400Å,

respectively.  

The specific surface, the pore volume and the pores Distribution of the particles according to the invention can be carried out by mercury via porosimetry or uptake and evaluation of nitrogen Sorption curves are determined in a known per se. The Maximum of the pore diameter and the average pore diameter can then be determined from this.

The particles according to the invention preferably show a mono modal pore distribution, wherein 80%, preferably 95%, of Pore diameters of the formula 0.8 R R 1.2 R, where R is the average pore diameter in the range of 15 to 400 Å equivalent.

Particular preference is given to particles based on Alumina having a pore volume in the range of 0.5 to 2.5 ml / g, preferably 0.7 to 2.5 ml / g, and a medium Pore diameter R in the range of 60 to 380 Å have.

The particles according to the invention can preferably be prepared by the process according to the invention which has already been indicated. In addition to a particularly uniform spherical shape and narrow grain spectrum, the particles according to the invention are characterized by a high pore volume with an unusually narrow distribution of pore diameters. It is particularly advantageous that at least 80%, preferably 95% of the particles have a pore diameter which is rich in the already specified Toleranzbe range of 0.8 RR 1.2 R. The proportion of macropores, ie pores with a diameter of more than 200 Å, is less than 5%. The particles according to the invention thus have a particularly homogeneous surface, which is particularly advantageous for their use as a catalyst support Ver. FIGS. 3A and 3B show, by way of example, electron micrographs of the surfaces of particles produced according to the invention, which show their homogeneous uniform surface structure. Another special feature of the particles according to the invention is that they show at their high pore volume a surprisingly high abrasion resistance, making them in connection with the high bulk density particularly suitable for use as catalysts or catalyst support in fluidized bed or fluidized bed reactors.

Furthermore, the invention includes the use of the after spherical particles prepared according to the invention as catalysts, catalyst supports, ion exchangers, adsorp drying and drying agents.

So z. B. with precious metals or transition metals doped catalysts are prepared, which after the According to the invention produced particles as Kataly carrier included. For example, they can be precious metals such as gold, silver, platinum, rhodium or palladium or transition metals such as copper. The content of such metals is usually in the range of 0.1 to 5 wt .-%, based on the finished catalyst support. Furthermore, metal ver bonds, z. As oxides of metals, in particular oxides of Transition metals, e.g. As oxides of manganese, iron, nickel or Cobalt, be included. Of course, mixtures of Me metals, mixtures of metal compounds or mixtures of one or more metals and one or more metal compounds gene to be applied to the carrier. For example, the Metal component of a catalyst according to the invention of Palla dium and / or rhodium or of palladium and copper. Such catalysts based on the invention Particles can z. B. in petrochemical or organic chemi rule synthesis method, for. In oxidation, hydrogenation, Oxychlorination or polymerization process, or in kataly used for wastewater and waste gas purification become. The preparation of the catalysts according to the invention can done in a known manner. For example, you can Metal salts or complex metal compounds in the impregnation process driving, spraying or precipitation on the particles apply and after drying and calcining if desired to reduce. The metals are preferably impregnated method, z. B. with a solution or suspension of metal salt zen or complex metal compounds in water or an orga niche solvent, applied to the particles. An advantage obtained on the basis of the particles produced according to the invention  Tenen catalysts is their high abrasion resistance.

The following examples are intended to explain the invention, but without restricting it.

Fig. 1 to 8:

Fig. 1: Schematic structure of an apparatus for carrying out he inventive method:
( 1 ): sol, ( 2 ): pump, ( 3 ): spraying device, ( 4 ): sol jet, ( 5 ): sol beads, ( 6 ): reaction zone with reaction gas, ( 7 ): reaction gas supply, ( 8 ): catching device, ( 9 ): sieve (optional) ( 10 ): collection container for the particles, ( 11 ): pump optional, ( 12 ): return of the reaction liquid into the collection container optional, α: angle α; d: variable distance between spray device and inlet opening in the reaction zone

Fig. 2: Schematic layout of another apparatus for carrying out the method according to the invention for small particles (0.001 to 0.3 mm)
( 1 ): sol, ( 2 ): spraying device with atomizing nozzle, ( 3 ): mist of small sol beads, ( 4 ): reaction zone with reaction gas, ( 5 ): collecting device, ( 6 ): reaction gas supply, ( 7 ): sieve (fa cultivar), ( 8 ): collection container, ( 9 ): pump, ( 10 ) optional: return of the reaction liquid into the collection container (optional)

Fig. 3: Electron micrographs of the surface texture produced according to the invention particles:

Fig. 3A: particles based on aluminosilicate 2.5-3.5 mm in diameter

Fig. 3B: particles based on silica with 0.4-0.6 mm diameter

Figures 4 to. 8:

Diagrams of the pore radius distribution according to the invention particles after mercury porosimetry:

They are each plotted on the axes:

x-axis: pore radius [A]

y-axis: cumulative pore volume [mm ³ / g]

Examples

The following Examples 1 to 8 were carried out in a device according to FIG .

example 1

According to the method of the invention, spherical particles were prepared based on silica. For this purpose, each separately an acidic solution and an alkaline Sili katlösung were provided with the concentrations given in Table 1 forth. In addition to the solutions, the mashes also indicated in Table 1 were added as fillers. The acidic or alkaline solution was combined with the corresponding Aerosil or SiO ₂ mixtures in the volume ratio indicated in Table 1 to the respective acidic or alkaline component.

The acid component SK and the alkaline component AK were mixed together in a mixing nozzle known per se at a temperature of about 10 ° C and further processed immediately and continuously in a device according to FIG . For this purpose, the sol obtained from the mixing together of the two components under a pressure difference of at least 2 bar at pH 6.4 was conveyed via the pump ( 2 ) and the cannula ( 3 ) (diameter: 3.7 mm, length: 10 cm) a throughput of 4 l / min in a sol beam ( 4 ) in the reaction zone ( 6 ) sprayed in such a way that the sol jet ( 4 ) when entering the reaction zone ( 6 ) in sol beads ( 5 ) torn. After passing through a curved trajectory through the reaction gas containing the reaction zone ( 6 ), the sol beads ( 5 ) were caught in the container filled with reaction liquid collecting container as a catching device ( 8 ). As reaction gas ammonia gas was used, which via the reaction gas supply ( 7 ) constantly WUR in the reaction zone ( 6 ) de filled. As the reaction liquid, an aqueous 5% ammonia solution was used.

The particles were aged in the aqueous ammonia solution for about 30 minutes and then separated from the reaction liquid via the sieve ( 9 ) and transferred to the collecting container ( 10 ). The reaction liquid was pumped via the pump ( 11 ) through the return ( 12 ) back into the collecting device ( 8 ).

The resulting particles were then known per se Replace with a 0.5% Ammoniumsulfatlö washed until sulphate-free, for 18 hours dried at 180 ° C and gettered at 600 ° C for 4 hours pert. Spherical particles with diameters in Be ranging from 2.5 to 3.5 mm, their bulk density, specific upper surface and pore volumes are given in Table 2.

Table 1

Composition of the use solutions and application components

Properties of the process products obtained according to Example 1 Diameter: 2.5-3.5 mm Bulk density: 0.9 g / ml specific surface: 334 m ² / g Pore volume: 1.01 ml / g Pore radius distribution: shown in Fig. 4 A)

Example 2

By the method according to the invention were spherical part made on the basis of aluminosilicate.

For this purpose, an acidic solution A and an al prepared silica silicate solution B:

The acidic solution A and the alkaline solution B were mixed together in a mixing nozzle known per se at a temperature of about 7 ° C and further processed in a device according to FIG. 1 so on and continuously.

For this purpose, from the mixing together of the two components under a pressure difference of at least 2 bar at pH 8.3 he held sol via a cannula of 3.7 mm diameter and 10 cm in length in an amount of 3.9 l / minute in a Solstrahl (4) sprayed into the reaction zone (6) in such a manner that the Solstrahl (4) at entry into the reaction zone (6) in sol beads (5) to tear.

After passing through a curved trajectory through the reac tion gas, the sol beads ( 5 ) were collected in the filled with reaction liquid collecting container ( 8 ). The reaction gas used was HCl gas, which was continuously replenished into the reaction zone ( 6 ) via the reaction gas feed ( 7 ). As the reaction liquid, an aqueous 2.5% HCl solution was added.

The particles were aged for about 30 minutes in the aqueous hydrogen chloride solution and then separated via the sieve ( 9 ) from the reaction liquid and transferred to the collecting container ( 10 ). The reaction liquid was pumped via the pump ( 11 ) through the return ( 12 ) back into the collecting device ( 8 ).

The resulting particles were then known per se Example, a base exchange with 0.5% sulfuric acid solution subjected to washing until free of sulphate, for 18 hours Dried at 180 ° C and annealed for 4 hours at 200 ° C.

Spherical aluminosilicate particles with diameters were obtained in the range of 2.5 to 3.5 mm, their bulk density, specific Surface and pore volume in the following Table 3 indicated are.

Properties of the process products obtained according to Example 2 Diameter | 2.5-3.5 mm bulk weight 0.77 g / ml surface 741 m ² / g pore volume 0.35 ml / g surface finish shown in Fig. 3A)

Example 3

Spherical particles based on alumina were prepared as follows:

A metastable acidic alumina hydrate sol (Condea Disperal® 30/2) having a composition of 14.19% by weight of Al ₂ O ₃ and 85.81% by weight of water was used in a device according to FIG. 1 by means of the pump ( 2 ). sprayed at a pressure of 6 bar over 10 cannulas (diameter: 0.70 mm, length: 3.2 cm) with a throughput of 0.75 l / minute from the bottom to the top, with the sol beams entering into the with Cracked ammonia gas filled reaction zone in a series of single equal Solperlen.

The following reaction conditions are given below:

Template: 5% ammonia solution aging: 1 h Dry: 8 h 120 ° annealing: 4 h 600 °

The obtained particles showed the following properties:

Example 3a Diameter: 0.4-0.6 mm Bulk density: 0.71 g / ml specific surface: 287 m ² / g Pore volume: 0.44 ml / g

Examples 3b to 3d

Some of the particles obtained according to Example 3 became one more subjected to additional heat treatment. In the following table 4 their properties are shown.

Table 4

Example 4

Spherical particles based on alumina were like in Example 3, prepared. In addition, these were Particles still a treatment with anhydrous isopropanol (Density: 0.785 g / ml). For a period of 2 hours for that, the obtained particles were each dried before drying 1 liter of isopropanol per 1 liter of particles. At egg In addition to the particles, the isopropanol treatment also became more performed by adding the particles from the isopropanol solution were decanted and then again for the same time were overlaid in an identical manner with isopropanol. This isopropanol treatment was up to several particles performed eight times in a row. After drying and cal zinieren, as already described in Example 3, was obtained Particles having the properties given in the table below companies.

From Table 5 shows that the pore volume, the bulk weight and the mean pore diameter of the inventions alumina particles produced according to the invention process itself  through the additional alcohol treatment in wide ranges vary.

Table 5

Properties of the process products obtained according to Example 4

The pore radius distribution of the particles according to Example 4a) is shown in FIG. 6A), which is shown in Example 4e in FIG. 6B).

Example 5

Spherical particles based on alumina were prepared as follows:

A metastable acidic Aluminiumoxidhydratsol (Condea Disperal® 30/1) with a composition of 18.00 wt .-% Al ₂ O ₃ and 82.00 wt .-% water was in an apparatus according to Fig. 1 by means of egg ner electrically driven spray gun (Bullcraft N, 80W) sprayed at a rate of 0.060 l / minute from bottom to top in the ammonia gas filled reaction zone. The following reaction conditions and the properties of the particles obtained are indicated below:

Template: 5% ammonia solution aging: 0.5 h Alcohol Treatment: twice 2 h, isopropanol   Dry: 8 h 120 ° annealing: 4 h 600 ° Diameter: 0.02-0.05 mm Bulk density: 0.43 g / ml specific surface: 291 m ² / g Pore volume: 1.19 ml / g Pore radius distribution: shown in Fig. 7A)

Example 6

Spherical particles based on alumina were prepared as follows:

A metastable acidic aluminum hydrate sol (Versal® 900) with a composition of 15.35 wt.% Al ₂ O ₃ , 0.38 wt.% HNO ₃ and 84.27 wt.% Water was used in a device according to FIG . 1 (diameter: 0.70 mm; length: 3.2 cm) with means of pump (2) at a pressure of 6 bar for 10 cannulas written as in example 3 be, at a rate of 0.75 l / Minute sprayed from bottom to top.

The following reaction conditions are given below:

Template: 5% ammonia solution aging: 1 h Dry: 10 h 180 ° C annealing: 6 h 600 ° C Diameter: 0.4-0.6 mm Bulk density: 0.66 g / ml specific surface: 190 m ² / g Pore volume: 0.58 ml / g Pore radius distribution: shown in Fig. 7B)

Example 7

Spherical particles based on silica were used prepared as follows:

A metastable silica sol (Bayer 200S, 30% SiO ₂ ), acidified to pH 4 with nitric acid, was placed in a device according to Fig. 1 by means of the pump ( 2 ) at a pressure of 6.5 bar over 10 cannulas (diameter: 0, 70 mm, length 3.20 cm) with a throughput of 0.73 l / minute sprayed from bottom to top, with the Sol rays in the filled with ammonia gas reaction zone in the same size Solperlen tore. The following reaction conditions and the properties of the particles obtained are indicated below:

Template: 5% ammonia solution aging: 0.5 h Alcohol treatment: twice 2 h, isopropanol Dry: 8 h 120 ° annealing: 4 h 200 ° Diameter: 0.4-0.6 mm Bulk density: 0.49 g / ml specific surface: 297 m ² / g Pore volume: 0.80 ml / g Pore radius distribution: shown in Fig. 8A) Surface texture: shown in Fig. 3B)

Example 8

By the method according to the invention were spherical part produced on the basis of silica.

For this purpose, an acidic solution A and an al prepared silica silicate solution B:

The acid solution A and the alkaline solution B were mixed together in a mixing nozzle known per se at a temperature of about 25 ° C and further processed immediately and continuously in a device according to FIG .

For this purpose, from the mixing together of the two components under a pressure difference of at least 2 bar at pH 8.3 he held sol via a conventional commercially available Spi raldüse (Spraybest, Greenfield, USA) in an amount of 1.2 l / minute in a Solstrahl ( 4 ) in the precipitation tower ( 6 ) in such a way that the Solstrahl ( 4 ) when entering the felling tower ( 6 ) in Solperlen ( 5 ) tore open.

After flying through a curved trajectory by the reac tion gas in the tower ( 6 ), the sol beads ( 5 ) were caught in the reaction liquid filled with Re container ( 8 ). As the reaction gas HCl gas was used, which was constantly refilled via the Re aktionsgaszufuhr ( 7 ) in the Fallen tower ( 6 ). As the reaction liquid, an aqueous 2.5% HCl solution was used.

The particles were aged for about 30 minutes in the aqueous solution of hydrogen chloride and then separated via the sieve ( 9 ) from the reaction liquid and transferred to the collecting container ( 10 ). The reaction liquid was pumped via the pump ( 11 ) through the return ( 12 ) back into the collecting container ( 8 ).

The resulting particles were then known per se As a base exchange with 0.5% sulfuric acid solution un terzogen, washed until the sulfate, for 18 hours at Dried 180 ° C and then processed differently, such as shown in Table 6 below. One received ball shaped aluminosilicate particles with diameters in the range of 0.9 to 1.5 mm, whose properties are also shown in Table 6 are guided.  

Table 6

Different further treatment steps and properties of the process products obtained according to Example 8

The pore radius distribution of the particles obtained according to Example 8b is shown in FIG. 8B).

Example 9 Determination of abrasion resistance

The abrasion resistance of Example 1 to 8 produced Particles were prepared by the following method for the determination of re tested for lative abrasion resistance: 1.0 g each of un The examining particles were placed in a 10 ml snap cap jar (45 x 22 mm) and weighed twice with 5 ml of demineralized water Water (DI water) rinsed to any adhering dust too remove. The superficially adhering water was with it aspirated a capillary, so that only in the pores water remained on the particles remained. It then became him Add 5 ml of demineralized water and the capped glass for 1 minute on a test tube shaker (Heidolf, Reax 1R)  Shaken at 2,400 rpm. 2 ml of the supernatant solution then transferred immediately to a 10 mm cuvette and the extinction worth E several times after repeated shaking with a wave length of 500 μm (Spectrophotometer CADAS 100, Dr. Lange) measured. For E values greater than 1, the sample became diluted accordingly, giving the linearity of the measured values was.

Mechanically stable and thus abrasion-resistant particles show below these experimental conditions E values in the range of 0.1 to 0.7.

The following Table 7 shows the who obtained in this test te for the relative abrasion resistance of Example 1 to 8 produced particles. Also, Table 7 contains Ver equivalent values for the abrasion resistance of alumina part chen, which WUR produced according to the prior art the.  

Table 7

abrasion resistance

Claims (15)

1. A process for the preparation of spherical particles Based on inorganic oxides by sol-gel conversion, in which one a sol in a reaction gas containing reaction zone of so injected below that the sol immediately before or only at Entrance into the reaction zone ruptures into individual sol beads and the formed sol beads on a curved trajectory the reac fly through zone, whereby they are pre-consolidated, and you then the pre-consolidated sol beads in a Auffangvorrich field. 2. The method according to claim 1, characterized in that Particles based on inorganic oxides from the group Magnesium oxide, alumina, silica, aluminosilicate, Zinc oxide, titanium dioxide, chromium oxide, copper oxide, manganese oxide, cerium oxide, tin oxide, iron oxide, nickel oxide, lead oxide, molybdenum oxide, Vanadium oxide, thorium oxide, zirconium and / or hafnium oxide forth provides. 3. The method according to claim 2, characterized in that Particles based on alumina and / or silicon produces dioxide or aluminosilicate. 4. The method according to claim 1, characterized in that one particles with an average diameter in the range from 0.001 mm to 5 mm, measured after drying. 5. The method according to claim 1, characterized in that as a catcher a slide or a smooth, given if necessary cooled collecting tray or one with a liquid filled collecting container begins. 6. The method according to claim 5, characterized in that  you enter a container filled with a reaction solution puts. 7. The method according to claim 6, characterized in that as the reaction liquid aqueous ammonia solution and as Re reaction gas uses ammonia. 8. The method according to claim 6, characterized in that as a reaction liquid equivalent to the reaction gas aqueous acid from the group hydrochloric acid, sulfuric acid or sal nitric acid and as reaction gas, hydrogen chloride or sulfur dioxide or nitric oxide. 9. The method according to claim 1, characterized in that the sol fillers from the group silicas, aluminosilicates, Aluminas, titanium dioxide, kaolin, montmorillonite, bentonite, Zeolite, starch, wood flour or activated carbon. 10. The method according to claim 1, characterized in that before drying with a pre-consolidated sol beads treated lower alkyl alcohol and / or acetone. 11. Spherical particles based on inorganic oxides, preferably based on silica, alumina or aluminosilicate, characterized in that they

• a) a diameter in the range of 0.001 to 5 mm, preferably 0.02 to 3.5 mm,
• b) a specific surface area in the range of 1 to 900 m ² / g, preferably 100 to 800 m ² / g
• c) a bulk density in the range of 0.1 to 1.0 g / ml,
• d) a pore volume in the range of 0.25 to 2.5 ml / g,
• e) have a distribution of the pore diameter with a maximum (mo nomodale pore distribution) in the range of 15 to 2000 Å, preferably 15 to 400 Å.

12. Spherical particles according to claim 11, characterized records that they have a monomodal pore distribution at  the 80%, preferably 95% of the pore diameter of the formula 0.8 R R 1.2 R, where R is the mean pore diameter in the range of 15 to 400 Å. 13. Spherical particles according to claim 11, characterized marked characterized in that they are based on alumina particles with a Pore volume in the range of 0.5 to 2.5 ml / g and a medium Pore diameters R are in the range of 60 to 380 Å. 14. Spherical particles based on inorganic oxides, obtained by a process according to claims 1 to 10. 15. Use of the according to claims 1 to 10 produced th particles as catalysts, catalyst support, Ionenaustau shear, adsorption or desiccant.