JPH04108654A - Starting material for extrusion-molding zeolite and its production - Google Patents

Abstract

PURPOSE:To improve the dispersibility of zeolite and the strength of a molded body after heat treatment by adding a surfactant to starting material for molding produced by mixing zeolite with clay, methylcellulose and water and specifying the wet mixing process. CONSTITUTION:Clay material prepd. by mixing a surfactant with water and clay by stirring is mixed with zeolite material prepd. by mixing methylcellulose with water and zeolite by stirring to produce starting material for extrusion molding. Since the surfaces of the zeolite particles are previously coated with methylcellulose molecules and then the surfactant is added, the surfactant is not adsorbed on the inside of the structure of the zeolite and the dispersibility of the zeolite can be improved. Extrusion molding is facilitated and the strength of a molded body after heat treatment can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a raw material for zeolite extrusion molding used in molding a zeolite molded body and a method for producing the same.

[Conventional technology]

Due to the unique pore structure of zeolite,
It is used as an adsorbent and a catalyst.

Known zeolites include natural zeolites such as mordenite and kliptylol zeolite, and artificial zeolites such as A-type and X-type zeolites, each of which is used for its own purpose.

Generally, natural zeolite contains a certain amount of impurities, including iron, and there is some variation in window diameter, which is an important factor in zeolite. Or, it is mostly used as a filler.

On the other hand, artificial zeolite has almost no contamination of elements other than zeolite constituent elements such as silica and alumina, and the crystal size can be easily controlled by controlling the hydrothermal treatment conditions during synthesis, so the window diameter can be reduced. It is uniform, and in addition to being used as an adsorbent for water, it has many industrial uses such as an adsorbent for gas adsorption and separation or a catalyst for hydrogenolysis.

It is known that ion exchange of certain ions into the zeolide structure is possible and that its properties can be controlled. For example, in artificial A-type zeolite, by changing the cations in the zeolite to + ions, Na + ions, and Ca + ions, the diameter of the entrance and exit to the zeolite structure (so-called window diameter) is approximately 30 and 4. , 5 people, and the adsorption separation characteristics of various gases change. Due to this effect, the window diameter of K+ ion A-type zeolite is 3 people, and the size of the molecules that can enter and exit is limited, and the size of molecules that can enter and exit is limited. Alternatively, it can only adsorb small molecules such as ammonia.

In A-type zeolite with Na+ ions, the window diameter is a little larger than 4, so carbon dioxide, -carbon oxide, C1, C2
It is also possible to adsorb paraffin.

In the Ca''+ ion Δ-type zeolite, the window diameter is even larger to 5, making it possible to adsorb even larger molecules such as C2°Ca olefins and cyclopropane.

In addition, Professor Iwamoto et al. of Miyazaki University (Catalyst, vol. 32, Nα
2.1990 etc.) revealed that copper ion-exchanged zeolites, especially copper ion-exchanged 23M-5 zeolites, exhibit high decomposition properties for the catalytic decomposition reaction of NO (NO''AN2N2O.).

In this way, ion exchange to zeolite is an important technology from the viewpoint of controlling zeolite properties.

Next, regarding the shapes of zeolites used, in order of decreasing size, so-called FCC catalysts are spray-dried granules with a diameter of 50 to 100 microns, and adsorbent catalysts are spherical products with a diameter of 1 to 3 mm (bead-shaped). , after transfer granulation or extrusion, spheroidization), columnar crystals (pellets,
Extrusion molded product) is - boat fishing. Furthermore, the use of a so-called honeycomb shape (a molded body with holes in a matrix) is being considered as a catalyst for promoting gas phase reactions.

Regarding molding of zeolite, spray-dry granulation or transfer granulation uses clay as a binder (based mainly on kaolin minerals) to zeolite in a ratio of 10 to 30%.
In spray dry granulation, a mixture of weight percentages is made into a slurry and then granulated using spray drying.In rolling granulation, powder and mist water are sprayed onto a rolling pan to form a transfer pan. Molding is performed while rotating. Technically, these techniques are complete and can be molded without any problems.

On the other hand, to form pellets or honeycomb-shaped products, zeolite, clay as a binder, and methyl cellulose as an organic binder are mixed in a dry or semi-dry method, kneaded in a kneader, and then extruded into a predetermined shape. ing.

[Problem to be solved by the invention]

The shape of zeolite is generally isotropic, such as a cube or a regular octahedron. Further, the size thereof is generally about 0.1 to 10 microns, and in many cases about 1 to 3 microns. Because of this shape of zeolite, when particles are precipitated in water, the precipitate becomes tightly packed and becomes extremely hard. Also, since zeolite itself is not sticky, it looks like it will solidify when mixed with water, similar to sand on a beach, but as the water dries, its cohesive strength disappears and it falls apart.

Zeolite powder has these properties, so
If you try to extrude this, it will tend to solidify in the compressed parts inside the extrusion molding machine, and in the worst case, it will solidify, and the molding part will heat up due to a large amount of heat, or the molding machine will stop working. This will cause problems that will cause it to stop.

In order to overcome the problems unique to zeolite molded bodies,
10 to 30 parts by weight of clay powder mainly composed of kaolin and 3 to 20 parts by weight of organic resin (binder) such as methyl cellulose are added to 100 parts by weight of zeolite, and after mixing these raw materials in a dry or semi-dry process, After adding water and kneading it in a dough-like state using a kneader, it is extruded into a pellet-like or honeycomb-like form using an extrusion molding machine.

After drying the molded body, the clay powder is dehydrated by heat treatment at a temperature higher than 500 to 600°C, solidified, and acts as a binder for the zeolite molded body. On the other hand, organic resins such as methylcellulose enter between particles such as zeolite during molding to facilitate molding and provide strength when drying the molded product. Since this organic resin is decomposed and burned away in the heat treatment step after drying the molded product, the areas where the resin was present become voids, which causes a decrease in strength.

Conventionally, in the molding of zeolite, it has been recognized that moldability has been improved to some extent by using clay and organic resin, and molding is only possible in special cases, that is, honeycomb shapes with a pitch of 10 mm or less,
It has been put into practical use except in very small cases where the wall thickness is 2 mm or less.

On the other hand, fine shapes, i.e., pitch 10 mm or less, wall thickness 2
[Currently, fine particles of 11171 or less have not been put into practical use due to the difficulty in molding the zeolite. It is thought that the reason why such problems remain is that the zeolite and clay powders are not uniformly dispersed and non-uniformity remains. It is also believed that the non-uniformity of the zeolite and clay powders also indicates a decrease in strength after heat treatment of the compact.

In view of the above-mentioned state of the art, the present invention seeks to provide a raw material for zeolite extrusion molding and a method for producing the same that does not cause the problems encountered in the conventional techniques.

[Means to solve the problem]

The inventors of the present invention have made extensive studies to overcome the above problems, and have come to the following conclusion.

(1) Zeolite has poor dispersibility.

(2) The clay powder added has poor dispersibility.

(3) The organic resin added is not uniformly dispersed.

Zeolite particles are usually about 1 to 3 microns in size, and when observed with a scanning electron microscope, the particles are independent and are judged to have good dispersibility. On the other hand, if zeolite particles alone are dispersed in water and left to stand, they will precipitate in a relatively short time of about one hour, and the precipitate will be so hard that it will not make a hole even when pressed with a spatula. This indicates that the dispersibility of zeolite is poor, and further improvement in dispersibility is desired in the new pickle.

On the other hand, it is understood that the clay powder and organic resin to be added are often mixed in a dry or semi-dry state, and that the dispersion is generally not uniform.

The present inventors conducted the following study to overcome the above problems.

First, we investigated the dispersion treatment of zeolite particles, and then the wet mixing process of raw materials.

Although attempts were made to improve the dispersibility of zeolite by using surfactants, little effectiveness was found as a result. The reason may be that the surfactant used is adsorbed inside the zeolite structure. As a countermeasure to this problem, the surface of the zeolite particles was first coated with a molecule such as CMC (carboxysotylcellulose), and then a surfactant was added thereto, thereby improving the dispersibility of the zeolite.

The present invention was completed based on the above findings, and
The present invention provides (1) a raw material for zeolite extrusion molding characterized by mixing a clay material obtained by stirring and mixing a surfactant, water and clay, and a zeolite material obtained by stirring and mixing methyl cellulose, water and zeolite; ) Surfactant: 0.1 to 5 parts by weight, Water: 20 to 10
A clay slurry prepared by stirring and mixing 0 parts by weight and 100 parts by weight of clay using a wet ball mill to have a viscosity in the range of 10 to 3000 cp, and methylcellulose 20.1 to 1.5 parts by weight.
Heavy 11! , water: 50 to 100 parts by weight and zeolite:
(3) A method for producing a raw material for zeolite extrusion molding, which comprises mixing 100 parts by weight of a zeolite slurry at a dry weight ratio of 30:70 to 10:90. Surfactant II 0.1 to 5 parts by weight,
Water = 20-100 parts by weight and clay: 100 parts by weight were stirred and mixed using a wet ball mill to obtain a viscosity of 10-3000c.
Clay slurry adjusted to p range and methylcellulose:
After mixing 0.1 to 15 parts by weight of In, water: 50 to 100 parts by weight, and zeolite: 100 parts by weight, the water was dehydrated and the zeolite cake was mixed at a dry weight ratio of 30:70.
This is a method for producing a raw material for zeolite extrusion molding, which is characterized by mixing at a ratio of 10:90 to 10:90.

Hereinafter, the present invention will be described with reference to examples of a system using zeolite, clay (kaolin) powder, surfactant, binder such as CMC, and water as raw materials. The effects of the present invention will become clear from these Examples.

〔Example〕

FIG. 1 shows one of the embodiments to which the present invention is applied. In Figure 1(a), ■ is clay (kaolin) powder, 2 is water,
3 is a surfactant, and 4 is an organic resin such as methyl cellulose which serves as a binder. These clay-based raw materials are mixed in a ball mill 5, prepared as a clay slurry 6 having a viscosity of 10 to 3000 cp, and stored.

On the other hand, in Fig. 1 et al.), 7 is zeolite, 8 is water,
Reference numeral 9 is methylcellulose, and these zeolite raw materials are mixed by a mixer 10, water is removed by a filter breath 11, and then stored as a zeolite cake 12.

Next, in FIG. 1(C), clay slurry 6 and zeolite cake 12 are uniformly mixed using a pressure kneader 13, extrusion molded using an extrusion molding machine 14, and then dried and heat treated 15. This is what we do.

If a zeolite molded body is prototyped according to this production method, (1) uniform dispersion of clay, (2) uniform dispersion of methyl cellulose as a binder, and (3) uniform dispersion of zeolite will be achieved, making extrusion molding easier, and The strength of the heat-treated zeolite molded product is improved.

A honeycomb-shaped molded body containing 20 parts by weight of kaolin powder and 80 parts by weight of X-type zeolite powder, 10 cm opening, 1 cm
An attempt was made to fabricate a pitch with a wall thickness of 1 mm).

A mixture of raw materials according to the present invention and a powder as a comparative example were dry-mixed, water and a binder (methylcellulose) were added, and the mixture was kneaded to form a raw material for extrusion molding.

As an example according to the invention, as kaolin powder 1, 20
The surfactant 3 is 1 part by weight of ammonium polycarboxylate, and the binder 4 is 5 parts by weight of hydroxypropyl methyl cellulose. Further, 80 parts by weight of zeolite powder 7 and 1 part by weight of carboxymethyl cellulose were used as methyl cellulose 9. The water was adjusted while controlling the viscosity as appropriate. The raw material obtained by mixing the clay slurry 6 and the zeolite cake 12 thus obtained was molded using an extruder 14 to obtain a honeycomb-shaped molded body. Furthermore, the strength of the obtained molded product was relatively high and could withstand operations such as drying and transportation. Furthermore, by heat-treating at 700°C, the strength of the organophilic molded body was maintained, and it was sufficient to be used as a catalyst or adsorbent.

On the other hand, as a comparative example, when a raw material for extrusion molding was prepared by dry mixing kaolin powder and zeolite powder, adding 7 parts by weight of hydroxypropyl methylcellulose and water, and kneading the mixture, the extrusion moldability was extremely poor and the moldability Although it was possible to obtain a molded product to some extent by increasing the pressure, the honeycomb had holes in its walls and was not satisfactory as a molded product. Although the strength after drying was strong enough for handling due to the effect of hydroxypropyl methylcellulose added as a binder, it became quite brittle after heat treatment at 700°C, making it difficult to use as a catalyst or adsorbent. It was difficult to do so.

It has been found that by improving the dispersibility of the raw materials in this way, it is possible to improve the extrusion moldability and the strength of the molded product (after heat treatment).

FIG. 2 is a flowchart of a manufacturing method adopted to further promote uniform mixing of zeolite and clay compared to the flow shown in FIG. 1.

In Figure 2(a), 1 is clay (kaolin) powder, 2
is water, and 3 is a surfactant. These are mixed uniformly using a ball mill to obtain clay slurry 4.

On the other hand, zeolite 5, water 6 and methylcellulose 7 were mixed in a mixer to make zeolite slurry 8, and clay slurry 4
and zeolite slurry 8 are mixed in a mixer 9 and dehydrated in a filter press 10 to obtain a raw material cake 11.

Next, as shown in FIG. 2, etc., a binder 12 such as methyl cellulose, water 13, and a raw material cake 11 are kneaded using a kneader 14, extruded using an extruder 15, and then dried. , heat treatment 16 is performed.

Similar to FIG. 2, FIGS. 3 and 4 show the basic flow shown in FIG. 1 except that the order of adding the binder is changed so that the zeolite, clay, and binder can be uniformly mixed.

In Figure 3(b), 1 is clay (kaolin) powder, 2
is water, 3 is a surfactant, and 4 is a binder such as methylcellulose. These raw materials are mixed using a wet ball mill 5 to form a clay slurry. On the other hand, zeolite 6
, water 7, and methyl cellulose 8 are mixed in a kneader 9 to form a zeolite slurry. Both slurries are mixed in a predetermined ratio using a mixer 10, and dehydrated using a filter press 11 to obtain a raw material cake 12.

Next, in Fig. 3 et al.), the raw material cake 12 is mixed into
3 and extrusion molding using an extrusion molding machine 14, followed by drying and heat treatment 15.

Furthermore, the flow of FIG. 4 is as follows. Figure 4(a)
In this step, clay (kaolin) powder 1, water 2, and surfactant 3 are uniformly mixed in a wet ball mill 4 to form a clay slurry. Next, zeolite 5, water 6, and methyl cellulose 7 are mixed in a kneader 8 to form a zeolite slurry. Methyl cellulose 9, which is a binder, and the clay slurry and zeolite slurry obtained in the above steps are mixed in a mixer to form a slurry, and dehydrated using a filter breath 11 to obtain a raw material cake 12.

Next, in FIG. 4(b), the raw material cake 12 is kneaded by a kneader 13, extruded by an extruder 14, and subjected to drying and heat treatment 15.

FIG. 5 shows the flow-stopping concentration in an aqueous system of clay powder (mineral type: Orin, average particle size 1.5 microns) for use in Georgia, USA. Flow stop concentration measurement is a simple and highly accurate method for obtaining an indication of the quality of powder dispersion. The method is to put powder (clay powder in this example) into a mixed solvent of a solvent (in this example, water is used) and a surfactant (in this example, ammonium polycarboxylate, with a molecular weight of 1000 is used). to make a slurry. When the initial amount of powder is small, the slurry has a low viscosity and flows, but as the amount of powder is gradually increased, the viscosity of the slurry gradually increases and the slurry stops flowing. Furthermore, increasing the amount of powder causes the slurry to solidify. The point at which this slurry stops flowing is defined as the flow stop point, and the flow stop concentration and surfactant amount are determined from the following equation.

The higher the dispersibility, the higher the flow stop concentration. In FIG. 5, the horizontal axis shows the surfactant and the vertical axis shows the flow stopping concentration. Blank value (value when no surfactant is added) is 5
3%, and when ammonium polycarboxylate is added as a surfactant, the highest flow stopping concentration of 80% is achieved with the addition of 1% ammonium polycarboxylate.

When calculating the flow stop points of 53% and 80% assuming that the solvent amount is constant, the powder amount at the flow stop points is 53 at 53% and 188 at 80%. It can be seen that with the presence of a suitable surfactant, ammonium polycarboxylate, it is possible to disperse about 3.5 times more powder in the same amount of solvent.

FIG. 6 shows the viscosity of the slurry obtained by slurrying clay powder manufactured by Joesia, USA, at various clay concentrations, and then mixing the slurry for 12 hours using a ball mill. In FIG. 6, the horizontal axis shows the clay concentration (%), and the vertical axis shows the slurry viscosity (p). Also,
In FIG. 6, ■ indicates the case where no surfactant was used, and ■ indicates the case where 1% ammonium polycarboxylate was added as a surfactant based on the amount of powder. It can be seen that by adding a surfactant, a slurry with a higher solids concentration and lower viscosity can be obtained.

Next, we investigated the dispersion of zeolite. As the zeolite, an X-type synthetic zeolite with an average particle size of 1.5 microns was used. Disperse 10 g of zeolite in 50 g of water using a homomixer at 2.00 Orpm for 3 minutes. After the dispersion treatment, pour the obtained zeolite slurry into a sedimentation tube at a height of 10 cm, and the zeolite The height of the sediment layer was observed. In FIG. 7, ■ to ■ are as follows.

■ Zeolite 10g + water 50g ■ Zeolite 10g + CMC (carboxymethyl cellulose ammonium salt) O, l g + water 49,9
g ■ Zeolite 10 g 10CMC0.1g + water 49.
85g + surfactant (ammonium polycarboxylate) 0
．． 05g ■ Zeolite, ) 10g + CMC0.1g++ + Water 4.8g + Surfactant (ammonium polycarboxylate)
0.1 g ■ Zeolite 10 g 10CMC0.1g++ Water 4.
7 g 10 surfactant (ammonium polycarboxylate) 0.2 g In Fig. 7, ▪ indicates the height of the sediment layer 1 hour after being placed in the sedimentation tube, and ▪ indicates the height of the sediment layer 12 hours later.

In case of ■, the sedimentation layer is poorly dispersed and the zeolite particles settle quickly, whereas in case of ■, the sedimentation is slow to some extent;
It was found that no sedimentation was observed in case (2). In case (2) of (2), the sedimentation layer was 4.5 cm, but a hard sedimentary layer of about 2 to 3 mm had formed at the bottom. In addition, ■ ■ is only a hard sedimentary layer. No hard sedimentary layer was observed in ■■, but a hard sedimentary layer of 1 to 2 mm in thickness was observed in ■■. No hard deposited layer was observed in (2), (2), (2) and (2), ■, and (2), and it was observed that the dispersibility of the zeolite particles was improved.

As in the previous example, the height of the zeolite sedimentation layer was examined by varying the amount of CMC, and the results are shown in FIG. In FIG. 8, ■ to ■ are as follows.

■ Zeolite Log + water 50g ■ Zeolite 10g + CMC0.1g + water 49,
9 ■ Zeolite 10 g + cMcO, 01 g + + water 4
．． 89g + Surfactant 0.1g ■ Zeolite 10g + cMc0.05g + Water 49
．． 85g + surfactant 0.1g ■ Zeolite 10g + CMC0.1g++ + water 4.8
g 10 surfactant 0.1 g ■ Zeolite 10 g 10 CMC 0.2 g ± + water 49
7g 10surfactant 0.1g ■ Zeolite 10g 10CMC0, 5g Shimizu 49,
4g+surfactant 0.1g (2) and (2) are the same as in FIG. In this example, it was considered that zeolite dispersion was achieved in cases ① to ②.

It has become clear that coating the zeolite surface with CMC is effective for dispersing zeolite, and that dispersion is further promoted by using a surfactant.

〔Effect of the invention〕

According to the present invention, a raw material for semilite extrusion molding that can maximize the dispersibility of raw materials (zeolite, clay), is easy to extrude, and can improve the strength of the zeolite molded product obtained by heat treatment is provided. can get.

[Brief explanation of the drawing]

Figures 1 to 4 are process diagrams showing the manufacturing process of raw materials for semilite extrusion molding according to different embodiments of the present invention, and Figure 5 is a flow stopping concentration depending on the amount of surfactant added to clay according to an embodiment of the present invention. Figure 6 is a diagram showing changes in viscosity concentration and viscosity depending on the amount of surfactant added to the clay of one example of the present invention, Figures 7 and 8 are graphs showing changes in CMC added to zeolite.
1 is a chart showing changes in the height of the sedimentation layer of the theolite slurry depending on the amount of surfactant.

Claims (3)

[Claims] (1) A raw material for zeolite extrusion molding characterized by mixing a clay material obtained by stirring and mixing a surfactant, water and clay, and a zeolite material obtained by stirring and mixing methyl cellulose, water and zeolite. (2) Surfactant: 0.1-5 parts by weight, water: 20-10
A clay slurry prepared by stirring and mixing 0 parts by weight and 100 parts by weight of clay using a wet ball mill to have a viscosity in the range of 10 to 3000 cp, 0.1 to 15 parts by weight of methyl cellulose, 50 to 100 parts by weight of water, and Zeolite: 100
A method for producing a raw material for zeolite extrusion molding, which comprises mixing a zeolite slurry obtained by mixing parts by weight at a dry weight ratio of 30:70 to 10:90. (3) Surfactant: 0.1-5 parts by weight, water: 20-10
A clay slurry prepared by stirring and mixing 0 parts by weight and 100 parts by weight of clay using a wet ball mill to have a viscosity in the range of 10 to 3000 cp, 0.1 to 15 parts by weight of methyl cellulose, 50 to 100 parts by weight of water, and Zeolite: 100
A method for producing a raw material for zeolite extrusion molding, which comprises mixing parts by weight and then mixing with a zeolite cake from which water has been dehydrated so that the dry weight ratio of the former to the latter is 30:70 to 10:90.