JPS61266306A - Fine spherical particle of crystalline aluminosilicate and its preparation - Google Patents

Abstract

PURPOSE:To prepare the titled fine spherical particles having high fluidity and strength and being useful as adsorbent and catalyst by granulating slurry comprising powdery crystalline aluminosilicate and specified binder. CONSTITUTION:Slurry of crystalline aluminosilicate and a binder obtd. by mixing slurry comprising 100pts.wt. powdery crystalline aluminosilicate and slurry medium (e.g. ethanol), with slurry comprising 2-50pts.wt. at least one binder selected from silicon alkoxide and alkali silicate, inorg. fine powder (e.g. silica), and the slurry medium (e.g. water) is spray-dried to obtain fine spherical particles of crystalline aluminosilicate having 10-500mu particle size.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to crystalline aluminosilicate microspherical particles that are used as adsorbents or catalysts and have excellent fluidity and strength, and a method for producing the same.

(Prior art) Various crystalline aluminosilicates (e.g., zeolites) have been used as adsorbents or catalysts in the adsorption separation of xylene, etc., production of gasoline or olefin gas from methanol, etc., and are being developed. . Aluminosilicate is often a crystalline powder with a size of around several μm, and in order to be used as an industrial material, it must be molded into an appropriate shape depending on the purpose of use.

For example, when zeolite is used as fluidized particles in various chemical processes, it exhibits sufficient fluidity, especially in a fluidized bed, has strength against wear during fluidization, and has sufficient chemical performance to meet the purpose. These physical and chemical properties are particularly required when fluidized zeolite particles are used as catalysts, and are particularly important for fluidized bed processes that use them as catalysts. This is an important performance that uniquely controls usability. Therefore, it is desirable that the particles be spherical in order to have good fluidity.

(Problems to be Solved by the Invention) As described above, spherical zeolite particles have high fluidity and are most ideal for use in fluidized adsorption beds or fluidized catalyst beds. However, it has not been possible to mold zeolite powder into a spherical shape.

Techniques for granulating highly sticky substances such as clay or gel into spherical shapes already exist. However, since crystalline aluminosilicate groups such as general natural and synthetic zeolites are crystalline, the adhesion of the powder particle sides is extremely low, so even when forming into a cylinder, it is difficult to compress it by applying a considerable external force. It is necessary to take this method.

On the other hand, even if spray drying was performed to form spherical granules, microspheres with sufficient strength could not be formed due to the condensation force of the zeolite powder aggregate itself.

That is, when only the raw material zeolite powder slurry is spray-dried, it can be formed into a ball with a certain degree of spherical shape, but it is easily broken and powdered by weak operations such as collection and transportation, and by vibration.

Therefore, the reality is that many zeolite products are generally formed into cylinders or pellets with a diameter of several millimeters by applying an external force, and then used.

(Means for Solving the Problems) The present inventors have conducted extensive research to overcome the difficulties in producing conventional microspherical particles of crystalline aluminosilicate, and as a result, we have developed It has been discovered that by using aluminosilicate crystals with a suitable binder, it is possible to create microspherical particles with sufficient strength to be used in fluidized beds.Based on this knowledge, the present invention has been made. I was able to complete it.

That is, the present invention provides microspherical particles characterized by comprising crystalline aluminosilicate powder and at least one selected from silicon alkoxide and alkali silicate as a binder, and crystalline aluminosilicate powder and silicon. The present invention provides a method for producing microspherical particles, which comprises preparing a starry made of at least one binder selected from alkoxides and alkali silicates, and granulating the starry.

The present invention will be described in accordance with the embodiment shown in FIG. This can be carried out by preparing an aluminosilicate-binder slurry and granulating it by spray drying or the like. A more detailed explanation will be given below according to the illustrated flow sheet.

In this method, first, crystalline aluminosilicate powder as a raw material is preferably mixed into a slurry medium to prepare a crystalline aluminosilicate slurry. The raw material crystalline aluminosilicate powder is generally used alone or with additives added if the target product is a crystalline aluminosilicate catalyst.
It can be pressure-molded into a tablet-like product, but as shown in the powder method, when spray granulation is performed, granulation is performed by the condensation force between particles, so the preparation process of crystalline aluminosilicate powder is difficult. The particle shape and strength vary depending on the history, especially the reactivity with the binder.

The slurry medium used for preparing the crystalline aluminosilicate slurry is pre-impregnated with the crystalline aluminosilicate powder to form a liquid-containing powder or slurry, so that the action of the binder can be stabilized. If it is not added, the slurry will begin to solidify in a few minutes, depending on the working temperature, and handling during the work process, especially the skill of manual labor, will affect the slurry, and if it is not added, the slurry will solidify in a few minutes. Granulation is not stable0 Alcohols, preferably ethanol or propatool, are effective as the slurry medium used in the method of the present invention, and the amount added is based on the weight ratio to the crystalline aluminosilicate powder used as the raw material. Approximately 1/10 to 10 times is preferable.

In the present invention, the surface coating shape of the crystalline aluminosilicate to be mixed with the slurry medium can be controlled by pre-treating it with acid or alkali. When the pH of this pretreatment is set to 6 to 8, the binder can be precipitated on the surface of the microsphere particles to completely cover the crystalline aluminosilicate. In this case, if the pretreatment is highly acidic or alkaline, the coating of the crystalline aluminosilicate is suppressed, leaving the crystalline aluminosilicate crystal powder exposed. In order to improve the bond between the crystalline aluminosilicate powder surface and the binder, it is recommended to adjust the solid surface acidity or basicity of the crystalline aluminosilicate powder according to the desired shape. preferable.

The crystalline aluminosilicate slurry is thoroughly stirred at room temperature, preferably in a sealed state.

It is best to use it in that state for the next step.

In the present invention, at least one of silicon alkoxide and alkali silicate is used as a binder.In the present invention, the binder is used in an amount of 2 to 50 parts by weight per 100 parts by weight of the crystalline aluminosilicate. Although the binder may be used as it is, it is preferable to add an acid or alkaline aqueous solution to the binder. Through this treatment, the binder is partially hydrolyzed.

For example, when silicon ethoxide (ethyl silicate) is used as a binder, the binding function of the binder changes depending on the reaction with an acid or base.

Ethyl silicate is hydrolyzed and polymerized by the addition of water or by the catalytic action of an acid or alkali to form a silicic acid polymer. Therefore, the degree of polymerization per degree of polymerization of this silicic acid polymer varies depending on the amount of water added, the concentration of acid or alkali, treatment temperature and treatment time. Furthermore, if an acid or alkali exists on the surface of the crystalline aluminosilicate crystal powder, hydrolysis occurs on these surfaces and polymerization proceeds. Therefore, the amount of acid or alkali on one surface depends on the surface of the crystalline fluminosilicate. It also affects the affinity with the silicic acid polymer that grows around it, and ultimately with the gel part that has a three-dimensional structure as a binder, changing the state of precipitation of the binder against the crystalline aluminosilicate powder. It becomes a factor.

In addition, this silicic acid polymer is partially generated during the preparation of the crystallizing agent, but it is also assumed to proceed during the slurry preparation process and the spray drying granulation process, and to be completed during the calcination process after granulation by the granulation method.

In the present invention, it is preferable to use the binder as a mixture of fine powder. When fine powder is used in this way, it is possible to prevent the crystalline aluminosilicate powder on the particle surface from being crushed. The amount of fine powder is in the range of up to 2/3 of the binder. In this way, fine powders are smaller than crystalline aluminosilicate powders, at less than 1/3 of the size of the raw aluminosilicate powder, and are stably dispersed in binders such as silica-based, silica-alumina-based, clay-based, etc. Examples include inorganic fine powders such as titania and mixtures of these components. The fine powder is distributed on the particle surface, and a part of the binder is precipitated on the particle surface in a layered manner to coat the crystalline aluminosilicate powder.

It is effective to add the fine powder to obtain microspheres coated with crystalline aluminosilicate, and by adding the fine powder, there is no need for acid and base treatment of the crystalline aluminosilicate powder as a raw material.

This fine powder is preferably added to the binder liquid after mixing with the slurry catalyst.

In the present invention, the crystalline aluminosilicate and binder slurry are preferably sufficiently stirred in a sealed state at room temperature, and preferably used in the next step in that state.

The mixed slurry of crystalline aluminosilicate and binder thus prepared is spray-dried to form particles that are spherical and have sufficient strength to be used in a fluidized bed.In the present invention, the spray-drying method is a conventional method. This can be done in accordance with.

In the present invention, the appearance of each particle can also be controlled by the temperature of the hot air during spray drying.Also by the zero method, it is possible to control irregularities, cracks, and craters on the surface of particles of a particle size by selecting spray drying conditions.

In spray drying, slurry droplets (spray) are generally created and dried and granulated in hot air, but the size of the microsphere particles can be changed depending on the size of the slurry droplets at this time.

(Effects of the Invention) According to the present invention, microspherical particles of crystalline aluminosilicate having high strength and a diameter of about 10 g to about 500 g can be obtained. This is an industrial material used in the fluidized bed method.
For example, it is suitable as an adsorbent, a catalyst, etc.

(Example) Next, the present invention will be explained in more detail based on examples.

Example 1 Raw material zeolite prepared by the method described in JP-A-59-97523 (50 g of Ca-containing Na star-shaped zeolite powder was thoroughly washed with water at pH 7 and then dried.
35 g of water glass No. 4 or 55 g of silicon ethoxide was added to form a slurry, which was spray-dried at 120 DEG C. and granulated to obtain sample 1-1 and sample 1-2, respectively. It was confirmed by electron microscopy that fine particles with a particle size of 20 to 200 pm were obtained, but the raw material zeolite powder was exposed in sample 1-1, and the zeolite powder was coated in sample 1-2.

The strength of sample 1-1 was such that it was not destroyed at all by a knife with a load of 5 g, whereas sample 1-2
10-20% was destroyed by a knife with a load of 5 g.

Example 2 50 g of the same raw material zeolite powder as in Example 1 was thoroughly washed with an aqueous solution of pH 4 and then dried, and 35 g each of water glass No. 1, No. 2, No. 3, and No. 4 was added to make a slurry of 12.
Sample 2- of microsphere particles were spray-dried at 0°C.
1 to 2-4 were obtained.

All of these exhibit shapes and strengths equivalent to Sample 1-1.

Example 3 50 g of the same raw material zeolite powder as in Example 1 was thoroughly washed with water of pH 7 and then dried, and silicon ethoxide 55
A silicon ethoxide acidic hydrate solution obtained by adding (a) 10 g of a 10'N nitric acid aqueous solution to a mixed solution of g and 25 g of ethanol, or (b) silicon obtained by adding 10 g of a 10-4 N ammonia aqueous solution. An ethoxide basic hydrate solution was added to form a slurry, which was spray-dried at 120°C to obtain microsphere particle samples 3-1 and 3-2, respectively. These exhibited strength equivalent to that of sample 1-1.

Example 4 50g of raw material zeolite powder similar to Example 1 was added to PHIO
Or, after thoroughly washing with an aqueous solution of pH 4, dry it, and add 1 ml to a mixed solution of 55 g of silicon ethoxide and 25 g of ethanol.
A silicon ethoxide acidic hydrate solution obtained by adding 10 g of a 0-'N nitric acid aqueous solution was added to form a slurry.
Two types of microsphere particles were obtained by spray drying at °C. All of these exhibit the same shape and strength as Sample 1-1.

Example 5 45 g of the same raw material zeolite powder as in Example 1 was thoroughly washed with an aqueous solution of pH 4 and then dried, and a 10'N nitric acid aqueous solution Log was added to a mixed solution of 55 g of silicon ethoxide and 25 g of ethanol to obtain silicon ethoxy. In addition, silica gel or silica alumina, titania, zeolite (mordenite), clay (karion) are added to the acidic hydrate solution.
Add 5g of fine powder with a tg or less to make a slurry of 120
Microsphere particle samples 5-1 to 5-5 were obtained by spray drying at ℃. All of these had the same shape as Sample 1-2 and exhibited strength equivalent to Sample 1-1.

Example 6 45 g of the same raw material zeolite powder as in Example 1 was thoroughly washed with an aqueous solution of PH4 and then dried, and 10 g of a 10'N nitric acid aqueous solution was added to a mixed solution of 55 g of silicon ethoxide and 25 g of ethanol to obtain silicon ethoxy. After adding 5 g of fine powder of silica gel below IIL to an acidic hydrate solution and adding liquid-containing powder to which 9 g of ethanol or 12 g of propatool was added, the mixture was spray-dried at 120°C to form microspheres. Particles were obtained. Both of these are sample l-2
It has the same shape as Sample 1-1 and the same strength as Sample 1-1.

Example 7 45 g of the same raw material zeolite powder as in Example 1 was thoroughly washed with an aqueous solution of pH 4, dried, and added to 90 g of ethanol or 120 g of propatool to form a liquid-containing powder, which was mixed with 55 g of silicon ethoxide and 25 g of ethanol. Slurry made by adding liquid-containing powder obtained by mixing 5 g of silica gel fine powder below IP and 9 g of ethanol to a silicon ethoxide acidic hydrate solution, which is obtained by adding 10 g of to-'N nitric acid aqueous solution to the mixed solution of After mixing, the mixture was spray-dried at 120° C. to obtain microsphere particles. These are both sample 1-
It exhibits the same shape as Sample 2 and shows the same strength as Sample 1-1.

Example 8 45g of mordenite powder or zeolite A powder was adjusted to pH
After washing thoroughly with the aqueous solution in step 4, dry it.

Add 90 g of ethanol to each to form a liquid-containing powder, and add silica gel to a silicon ethoxide acid hydrate solution obtained by adding 10 g of io'N nitric acid aqueous solution to a mixed solution of 55 g of silicon ethoxide and 25 g of ethanol. A liquid-containing powder obtained by mixing 5 g of fine powder of 1 liter or less and 9 g of ethanol was added to a slurry and mixed.Then, each mixture was spray-dried at 120°C to obtain microsphere particles. Both of these exhibit the same shape as Sample 1-2 and exhibit the same strength as Sample 1-1.

[Brief explanation of drawings]

FIG. 1 is a process diagram for producing microspherical particles of crystalline aluminosilicate according to the present invention.

Claims (1)

[Scope of Claims] 1. Microspherical particles comprising crystalline aluminosilicate powder and at least one selected from silicon alkoxide and alkali silicate as a binder. 2. A method for producing microspherical particles, which comprises preparing a slurry consisting of crystalline aluminosilicate powder and at least one binder selected from silicon alkoxides and alkali silicates, and granulating the slurry. .