JPS61155216A - Molding method of zeolite - Google Patents

Abstract

PURPOSE:To make the shape uniform and to enhance the mechanical strength and abrasion resistance of a molded product by kneading and roughly granulating the mixture of a zeolite, binder, etc., to make lumps having a prescribed particle diameter and by extrusion-granulating said lumps. CONSTITUTION:The mixture of a zeolite, binder and granulating agent is kneaded and roughly granulated to adjust the particle diameter to 1-50mm. These granular lumps are extrusion-granulated to obtain the molded product of zeolite. The shape of the molded product is always made uniform, and the mechanical strength and abrasion resistance of the molded product are enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION In particular, the present invention relates to a method for producing a zeolite molded product with high strength and wear resistance, which enables stable operational control of the granulation process and stable quality control.

<Industrial Application Fields> Zeolite has excellent adsorption properties. Ion exchange properties,
Application of functions such as catalytic properties, drying, purification. Numerous applications have been developed for separation, ion exchange, catalysts and catalyst supports, and are used in petroleum refining, chemical and petrochemical industry, gas refining industry, natural gas industry, and electrical industry.

It is used in the paint industry, other 4m glass applications, analysis applications, etc.

Here, zeolite includes naturally occurring natural zeolite and synthetic zeolite produced by synthesis, and has the general formula % (in the formula, M is an alkali metal or alkaline earth metal, and n is their valence). There is a crystalline aluminosilicate with the composition expressed by . one.

The zeolite in the present invention does not specify either natural zeolite or synthetic zeolite. Furthermore, although the cations contained in zeolite can be easily ion-exchanged into other cations, the zeolite used in the present invention does not specify this cation.

Among zeolites, synthetic zeolite itself is CL.
It is a fine crystal or aggregate of crystals in the range of 1 to 50 microns, and is a non-binding powder. In order to use this product industrially, it is necessary to make it into some kind of molded product suitable for the purpose of use. The shape of the molded product is generally columnar (bellet).
1 spherical (bead).

There are granules and fine particles, and for special purposes there are shapes such as honeycomb, tube, plate, and core shapes.

<Prior Art> In order to granulate zeolite, generally 10 to 30 parts of a binder is added to 100 parts by weight of the dry zeolite. As the binder, clays such as kaolin, attapulgide, montmorillonite, bentonite, allophane, and seviolite are used alone or in combination of two or more. As binders other than clay, alumina, silica, etc. are also used alone or in combination with clay. In addition to the binder, various organic and inorganic additives are often used alone or in combination as granulation aids in the range of 0.01 to 5 parts per 100 parts of the dry weight of the zeolite. Examples of granulation aids include methylcellulose, carboxymethylcellulose, polyvinyl alcohol, crystalline cellulose, lignin, stearic acid,
These include starch, gum arabic, sodium silicate, and sodium polyphosphate.

Zeolite granulation methods include, for example, transfer granulation, extrusion granulation, spray granulation, fluidized granulation, and compression granulation, and the present invention relates to extrusion granulation. When producing a zeolite molded product by extrusion granulation, the zeolite powder and the powder of the binder and granulation aid are dry-mixed in advance using a known mixer such as a ribbon blender or a conical blender. Add liquid using a mixer.

It is common to add water, knead, and then extrude and granulate.

The granulation aid may be added in advance as an aqueous solution.

<Problems to be solved by the invention> Among the several characteristics that zeolite molded products must have, mechanical strength is one of them.

Examples include wear resistance and uniformity of shape. When molding zeolite by extrusion granulation, there are a very large number of governing factors that affect these product properties, and since each of these governing factors has a synergistic effect, the granulation mechanism has not been systematically elucidated. The current situation is that there is no such thing. The controlling factors that can be considered in granulating zeolite can be roughly divided into 1) raw materials, 2) pre-processes, and 3) granulation steps.

First, when considering raw materials, there are particle shape, physical properties, particle size distribution, moisture content, temperature, type of binder and its addition ratio, etc. The particle shape depends on the type of zeolite and its synthesis method (
The type of clay used as a binder also varies depending on the type of binder. In terms of physical properties, zeolites generally have dilatancy, and clays exhibit thixotropy. Furthermore, the powder characteristics vary widely depending on the type of zeolite and the type of binder clay. The amount of attached water and the amount of crystallized water differ depending on the degree of dryness of the zeolite powder and the type of zeolite.

Also, even in clay, there is crystallized water, interlayer water, and attached water.
It varies depending on the type of clay, drying time, storage atmosphere, etc.

Next, regarding the pre-process, typical controlling factors include dry powder mixing time, liquid/water addition time and method of addition, presence or absence of plasticity, kneading machine type, kneading time, temperature, etc. Controlling factors in the granulation process include granulation shape, granulation hardness and softness, adhesion, aperture ratio of a die or screen and its thickness, extrusion speed, and screen type.

Among these many controlling factors, when the equipment used and the combination of zeolite, binder, and granulation aid are specified, the factor that most controls the granulation property is the amount of liquid added and the amount of water added.

In other words, comprehensive moisture management is the biggest problem. As described above, zeolite contains water of crystallization, and depending on the drying conditions of the zeolite powder, the amount of water of crystallization and the presence or absence of attached water may vary. On the other hand, regarding the clay used in the binder, crystallization water, interlayer water, and interlayer water each vary. In addition, heat generation occurs in each process of dry powder mixing, kneading, and granulation, and the amount of evaporated water changes depending on the temperature and humidity of the process atmosphere. For these reasons, it is difficult to comprehensively control moisture during granulation, and conventionally, the moisture content after kneading has been measured each time and the moisture content has been adjusted to the optimum conditions.

Specifically speaking, the reason why moisture management is necessary is that if the moisture content after kneading is lower than the optimum moisture content, the load on the extrusion granulator will increase, causing heat generation in the die or screen section. increases, the granulation becomes unstable, and the shape of the molded product becomes sasafure or cracked. On the other hand, if the water content after kneading is higher than the optimum water content, the molded products will adhere to each other after extrusion granulation, and a uniform shape will not be maintained, and the mechanical strength of the molded product will also decrease. The allowable range for this optimum water content is extremely low, ±0.5%, and if a kneaded product with a water content outside this range is extruded and granulated, the aforementioned operational instability and product properties will deteriorate. For this reason, in the process control of granulation, careful attention has been paid to moisture control and a huge amount of effort has been expended.

As a result of intensive study on a method for constantly controlling this moisture content to the optimum value, the present invention has discovered that granulation can always be carried out under optimum conditions by controlling the shape of the kneaded coarse granulated mass in the previous step. We have now provided a method for producing molded products with high mechanical strength as well as grain stability and quality stability.

Means for Solving Problems 111> The present invention provides dry powder mixing of some or all of the zeolite, binder, and granulation aid in a mixer 12, and the mixed powder being subjected to rotating motion in the same machine or in another machine. Add water or add a solution in which part or all of the granulation aid is dissolved or dispersed,
The particle size of the kneaded coarse granulated mass consisting of zeolite, binder, granulation aid and water is in the range of 1 to 50, preferably 1 to 30.
The kneaded coarse granulated mass is then granulated by extrusion.

In the kneading process for producing zeolite molded products, the three phases of the solid zeolite, binder, and granulation aid, the liquid (mainly water and a part of the granulation aid solution), and the gas (mainly air) are filled in some way. Formed with style. In order to stably perform extrusion granulation, the ideal wet powder, that is, the filling mode of the kneading arms, is solid.

Formation of three phases: liquid and gas; solid phase is continuous; liquid phase is continuous;
There is no gas phase. In other words, the ideal state is that there is only enough liquid to fill the solid phase surface and the voids between the solids, and there are no voids where gas exists, and if the kneading arms are granulated in this state, the mechanical strength of the molded product will decrease. is high and has high wear resistance. In order to create a kneading arm in this ideal state, it is sufficient to apply force to cause the powder to coagulate and adhere under a rotating motion, and to add sufficient liquid to fill the voids. Here, as a guideline for the amount of liquid sufficient to fill the voids, the kneading arms are spherical,
The particles are coarsely granulated to have a particle diameter of 1 to 50 m, preferably 1 to 30 m.

For example, if mixed wire powder is extruded and granulated in powder form for less than 1 hour after mixing, there will be signs of moisture deficiency, that is, heat generation will increase in the screen or die part of the granulator, and the granulation will not be stable. There are noticeable cracks or cracks in the shape of the molded product.

On the other hand, if the crosstalk becomes a coarse granulated mass with more than 50 lines after crosstalk,
When this is extruded and granulated, signs of excessive water content, i.e., the molded products adhere to each other, and their mechanical strength also decreases.

Although the size of the cross-wire coarse granulation mass depends on the swirling time and swirling speed, it changes the most depending on the amount of water added or the amount of liquid added. The binder and granulation aid are selected in a combination that facilitates agglomeration of all components including zeolite, and the minimum agglomeration units in the cross-wire adhere to each other in the presence of moisture and grow in a snowballing manner. The amount of water in this state controls the size of the kneaded coarse granules, and the appropriate amount of water is the amount that permeates into the minimum unit of agglomeration, and if more water is added, the water stagnates on the surface of the agglomeration. However, this promotes mutual adhesion and rapidly increases the size of the coarsely granulated lumps.

From the above, in order to bring the optimum moisture content for granulation, it is necessary to add water or add liquid so that the size of the coarse granulated lumps in the previous step is in the range of 1 to 5 Qmm, preferably in the range of 1 to 60 Qmm. I know it's good. The details will be explained below.

<Function> In the extrusion granulation method according to the present invention, in the previous step of kneading the mixture with zeolite, binder, and granulation aid,
This is a method of adding water or liquid so that the particle size of the kneaded coarsely granulated mass becomes in the range of 1 to 5 Qmm, more desirably in the range of 1 to 3 Qmw. If the kneaded coarse granulated mass in the above range is extruded and granulated, the operation of the granulation process will always be stable, and in addition, the shape of the molded product will be uniform, mechanical strength will be increased, and wear resistance will also be increased.

Furthermore, there is no need to measure moisture during or after kneading, and process control can be greatly simplified.

<Effects of the Invention> As is clear from the above explanation, according to the present invention, (1)
The shape of zeolite molded products should always be uniform.

(2) The mechanical strength and abrasion resistance of zeolite molded products can be improved.

(3) The granulation process of zeolite molded products is always stabilized, making operational management easier.

(4) Moisture adjustment in the pre-granulation process of zeolite molded products becomes easy, and process control such as moisture measurement can be omitted.

<Example> The present invention will be explained in detail below with reference to Examples.

Note that the present invention is not limited to the zeolite, kinder, granulation aid, and equipment used in the Examples.

[Example 1] Weighed 1.22 kg of 4A type zeolite powder (as anhydrous 4.14 to 9), 1.22 kg of acid clay powder, and 40 g of carboxymethyl cellulose powder, and used a vertical mixing stirrer Henschel mixer FM750 model. (manufactured by Mitsui Miike Seisakusho), peripheral speed 2G, 2? ? Dry powder mixing was performed for 10 minutes at θC/day. After that, 2.25 kg of pure water was applied at a circumferential speed of 1
After addition for 50 seconds under the rotating condition of α7 m/sec, the rotational speed was increased to a circumferential speed of 20.2 m/sθC, and crosstalk was continued for 5 minutes. As a result of measuring the particle size distribution of the kneaded coarse granulated mass taken out from the Henschel mixer, it was found that
~20++ll+! 8chi, 20-30m85%,
It was 30+Xl1 or more and 2ch. This kneaded coarse granulated mass is extruded into the granulator 11! ! XDF-100 type (manufactured by Fuji Paudal)
It was granulated with The mounting die has a hole diameter of 3+++s and a die thickness of 10mm. Granulation was very smooth and well-shaped pellets were obtained. After drying this in a fluidized bed dryer with hot air temperature of 120°C for 30 minutes, it was heated to 550° in a static electric firing oven.
It was fired for 22 hours. The mechanical strength of the fired pellets was measured at 20 points using a bookstore type hardness tester, and the average value was 92.9.

[Comparative Example 1] The same amounts of zeolite, acid clay, and carboxymethyl cellulose as in Example 1 were weighed, and kneader-FM-NW-2 was prepared.
The mixture was placed in a Model 0 (manufactured by Fuji Kikaki) and mixed for 10 minutes. Thereafter, 2-25% pure water was added over 1 minute, and the mixture was kneaded for 50 minutes. The kneaded material taken out from the kneader was in powder form and no cross-wire coarse granule agglomerates were observed. This kneaded product was granulated, dried, and fired in the same manner as in Example 1, and the mechanical strength of the pellets was measured, and the average value was 5.5 to 9. During granulation, the pellets were not extruded from the entire surface of the die, and there were some clogged holes and rough edges on the surface of the pellets.

[Example 2] Synthetic mordenite powder form 11.21c9 (10 kg as anhydrous), acid clay powder form 2.94 and carboxyl methyl cellulose 1009 were each weighed and mixed in a Henschel mixer at a circumferential speed of 2 El 2 m/sec. 10
After mixing dry powder for a minute, add pure water & 25 to 9 at peripheral speed I CL
added over 30 seconds under 7 m/sec,
After 10 minutes of increasing the rotational speed to a circumferential speed of 2z3m/8θC, signs of coarse granulation agglomeration were observed, but the rotation was continued for another 10 minutes. As a result of measuring the particle size distribution of the kneaded coarse granulated mass taken out from the Henschel mixer, it was found that the particle size distribution was 10 cm or less, 12 cm or less, 10 ~
The score was 75 cm for 20 yen, and 13 cm for 20 yen. This mixed wire coarse granulation mass was formed into a die with a hole diameter of 1.5 rns and a die thickness of 4+.
The mechanical strength of the pellets, which were granulated using an extrusion granulator equipped with a +m die and subsequently subjected to the same post-treatment as in Example 1, was 2.5 kg on average. The granulation state was smooth and the shape of the pellets was good.

[Comparative Example 2] After carrying out the same procedure as in Example 2 up to dry powder mixing, pure water & 59 kg
were added at the same circumferential speed and addition time, and crosstalk was performed.
After 10 minutes, the coarse granulated mass had grown large, so it was taken out from the Henschel mixer and its particle size distribution was measured. the result,
All of them were dumpling-shaped masses ranging from 50 to 100 people. This was subjected to extrusion granulation under the same conditions as in Example 2, but
Because the particle size of the coarse granulated mass is large, it is difficult to get caught in the extruder screw, and the pellets adhere to each other strongly after extrusion.
The shape was non-uniform. The mechanical strength of the molded products was 1.5 kg on average.

[Example 3] Synthetic mordenite powder form 12.5PC9 (10 kg as anhydrous), Kibushi clay powder form xoICg, and carboxymethyl cellulose 2oo9 were each weighed and dried in a Henschel mixer at a circumferential speed of 20.2 m/sθC for 5 minutes. After mixing, a 4 to 9 solution of crystalline cellulose was added and kneaded for 5 minutes. Since generation of coarsely granulated lumps was not observed, further 5609 g of pure water was added, and mixing was continued for 5 minutes.

The particle size distribution of the kneaded coarse granulated mass taken out from the Henschel mixer was 10-20mm 65%, 20-30mm55
%Met. The pellets were granulated using a 3-hole diameter die and subjected to the same post-treatment as in Example 1. The average mechanical strength of the pellets was 49. Note that the granulation was smooth and had a good shape.

[Comparative Example 3] In the same manner as in Example 3, after adding up to 50% of the crystalline cellulose solution, 800 g of pure water was added and mixed for 5 minutes. All of the kneaded coarse granulated lumps taken out from the Henschel mixer had a particle size of 40 to 60 mm in the form of lumps, the pellets after granulation adhered to each other, and the average mechanical strength was 4JC9.

Patent applicant: Toyo Soda Kogyo Co., Ltd. Procedure Ne…Authentic book (formal entry) May 16, 1985

Claims (1)

[Claims] (1) When granulating a zeolite molded product formed from a mixture of zeolite and a binder, the particle size of the kneaded coarse granulated mass of the mixture of zeolite, binder, and granulation aid is adjusted to 1 to 50 mm, A method for forming zeolite characterized by extrusion granulation.