JPS6121726A - Preparation of inorganic spherical body - Google Patents

Abstract

PURPOSE:To enhance the strength of a product by making the shape of the product constant, by spraying a solution or sol of an inorg. substance to a liquid repellent surface to deposit liquid droplets on said surface and drying said liquid droplets before removing the formed inorg. spheres from said surface. CONSTITUTION:A material selected from a solution, soln or gel of an inorg. substance is sprayed to a liquid repellent surface to be deposited to the aforementioned surface as liquid droplets. Subsequently, said liquid droplets are dried on said surface and the formed inorg. spheres are removed from the surface and, if necessary, baked to prepare inorg. spheres. For example, when water is used as a main solvent, a sheet comprising a material having liquid repellency such as polyvinyl chloride, a fluorocarbon resin or polyethylene or one comprising a metal or other metarial treated with a water repellent agent such as silicone or a fluorocarbon resin can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing inorganic spherical bodies, and more particularly to a method for granulating an inorganic substance into spherical bodies having a particle size in the range of 0.1 to 100 μm.

−゛Yo ■? Conventionally, a spray drying method has been commonly used to granulate inorganic substances into spherical bodies having a size of 0.1 to 100 microns. This method requires large-capacity equipment because the sprayed liquid must be dried while in the spray state. Furthermore, because of the rapid drying, the product tends to lose its spherical shape and become weak.

The present invention involves spraying a material selected from an inorganic solution, sol, or gel onto a liquid-repellent surface to deposit droplets on the surface. This is a method for producing inorganic spheres, which is characterized by drying the inorganic spheres on the surface, removing the generated inorganic spheres from the surface, and firing if necessary.

According to this method, unlike the spray drying method, large-capacity equipment is not required, the shape of the product is almost constant, and a product with high strength can be obtained.

The raw material liquid that can be used in the method of the present invention may be any inorganic solution, sol, or gel, and any mixture may be used as long as it does not clog the spray nozzle and can be dried. For example, Mg+AI+Si+Ca+Sc,
Tt+ V+ Cr, Mn+ Fe, Go, N
+, Cu, Zn+ Ga+Ge+ Sr+ 'Zr
+ Nbl Mo, Te, Ru, Rb+ Ag+
Oxides, hydroxides, salts, and mixtures thereof such as cd, Ir++Su+Sb, and Ba+Hf are used.

The solvent is usually water, but it may also be an organic solvent or a mixture of water and an organic solvent, as long as it can form droplets when sprayed onto a liquid-repellent surface.

As the spray device, a normal air spray, an airless spray, or a centrifugal spray device using a rotating body can be used, but it is preferable to use one with a particle size distribution as narrow as possible.

The liquid-repellent surface may be a sheet whose material itself is liquid-repellent, or even a non-liquid-repellent sheet can be surface-treated to impart liquid repellency and used.

Such materials are well known; for example, when water is used as the main solvent, sheets of water-repellent materials such as polyvinyl chloride, fluororesins, and polyethylene, or sheets of water-repellent materials such as silicone, fluorine resins, and paraffin are used. A sheet of metal or other material treated with a water agent can be used.

It is obvious that the concentration of the inorganic substance in the solution, sol, or gel should be as high as possible without clogging the spray nozzle and allowing satisfactory spraying.

In order to dry the droplets of the raw material liquid sprayed on the liquid-repellent surface, heating means such as hot air, an infrared lamp, or microwave can be used.

Although the process according to the invention can be carried out batchwise, it is advantageous to carry it out continuously using an endless belt with a liquid-repellent surface. In that case, the raw material is sprayed on the upstream side of the Endless Held, then the sprayed raw material passes through a drying chamber in the form of droplets, and the dried and solidified inorganic spheres are scraped off from the Endless Held on the downstream side and collected. Just do it. This inorganic spherical body is fired if necessary for the purpose of improving hardness (fracture strength), removing impurity components, etc.

The inorganic spheres obtained in this way can be used in cosmetics, paints, etc. by taking advantage of the spherical shape of the particles.
It can be used as an additive for inks, resins, etc., a raw material for denitration catalysts, a raw material for ceramics, etc.

Example 1 +5 of Ti Niazol ■ Ti0z250 g/j! and free sulfuric acid 500g/
Heat 800 d of titanyl sulfate solution containing j8 to 105°C, and separately heat water to 95°C in a three-necked flask, and add 50 ml of the above titanyl sulfate solution into this while stirring.
It was added at a ratio of min. After the addition was completed, the mixture was heated to continue hydrolyzing titanium oxide for 2 hours. After passing this through a suction port, the passed cake was dispersed in 1000 ae of warm water. The mixture was separated again on a daily basis to obtain 570 g of a mouth cake.

■ A slurry made by dispersing this cake in 700ml of water
)l was 1.3. Concentrated aqueous ammonia was added dropwise to this slurry while stirring to neutralize it to pH 5.5. This material was passed through the suction port again and washed with 1000 d of warm water to thoroughly compress and dehydrate the cake.

Concentrated hydrochloric acid is added to this cake to thaw it and pH
A translucent and fluid Chiknia sol containing 40% of 1,5, TiOz was obtained.

The titania sol obtained by the above method is coated with Teflon (fluorine resin).
The seat uses Ikeuchi Akijet, air pressure 5kg/cTA, hydraulic pressure 2kg/cn! It was coated with The sprayed Teflon plate was placed in a dryer, and after drying at 100° C. for 1 hour, the titanium spheres were scraped off with a brush. This titanium spherical body was fired at 900"C for 2 hours to form a 1-10μ
(average particle size 5 μm) titanium oxide spheres were obtained.

The same chilinia sol ￥AMATO type parbyl minisufu'
Compared to those spray-dried at 100°C using Ray-GB-21 and then fired at 900°C, this spherical body is hard and has very good sliding (hairing effect), and can be used in resins, ceramics, paints, etc. It was found that it is an excellent additive for cosmetics, etc. In addition, the surface of the titanium oxide spherical bodies obtained was treated with zirconium by a method of hydrolyzing zirconium sulfate or a method of treating with organic zirconium, and then fired at 1200°C. I knew it would go up.

Example 2 In Example 1, commercially available silica sol (Cataroid, Catalysts & Chemicals Industry ■) or alumina soil (Colloidal Alumina Chemical Industry @) was used in place of Chilinia sol, and inorganic spheres were prepared by spraying, drying, and baking under the same conditions. I got it.

When observed under a microscope, this product had very uniform spherical bodies compared to the product obtained by direct spray drying.

Claims (5)

[Claims] (1) Droplets are deposited on a liquid-repellent surface by spraying a material selected from an inorganic solution, sol, or gel, and the droplets are dried on the surface. A method for producing an inorganic spherical body, which comprises removing the generated inorganic spherical body from the surface and firing it if necessary. (2) The method of item 1, wherein the material is titania sol. (3) The method of item 1, wherein the material is silica sol. (4) The method of item 1, wherein the material is alumina sol. (5) The method according to any one of Items 1 to 4, wherein the particle size of the inorganic spheres is in the range of 0.1 to 100μ.