JP2003112918A - Producing method for artificial zeolite - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently facilitate a reaction between a raw material containing silicone and/or aluminum and an alkaline aqueous solution represented by sodium hydroxide solution in the production of zeolite by means of a batch method. SOLUTION: When the raw material containing a prescribed quantity of silicone and/or aluminum is reacted with the alkaline solution represented by sodium hydroxide solution by means of a batch method, the mixed liquid in a reaction tank is guided outside the reaction tank by using a circulation pump, and thereafter, is returned to the reaction tank again and the circulation is repeated for a prescribed time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mixes and stirs a raw material containing a predetermined amount of silicon and aluminum and an alkaline aqueous solution represented by sodium hydroxide in a reaction tank equipped with stirring blades by a batch method. Let it react,
The present invention relates to a method for producing an artificial zeolite by moving the mixed solution to a predetermined next step.

[0002]

2. Description of the Related Art Conventionally, a raw material containing silicon and aluminum and an alkaline aqueous solution represented by sodium hydroxide (for example, coal ash and sodium hydroxide) are mixed in a reaction tank equipped with a stirring blade to carry out a reaction. There have been various methods for producing zeolite by using the above method, but originally, as shown in FIG. 2, it was general to carry out by a batch method in which a stirring blade 7 was provided inside the reaction tank 1. After that, in order to solve the problem of the processing capacity of the batch method (processing capacity per unit time), for example, Japanese Patent Laid-Open No. 9-2
No. 55325, it is also proposed to carry out by a continuous processing method.

[0003]

However, in such a continuous treatment system, it is required to promote the reaction of the two while the mixed solution is allowed to flow without stagnation. Therefore, a plurality of reaction tanks should be prepared. However, it is necessary to respectively provide a circulation pump, a heating means, etc. for sequentially feeding the mixed liquid to these tanks, and therefore, there is a problem that the entire apparatus becomes very large and the equipment cost increases. on the other hand,
A method has also been proposed in which an ultrasonic vibration source is provided on the side or bottom of the reaction tank, and ultrasonic waves are applied to the mixed liquid to increase the mixing efficiency. The range of its spillover effect was extremely small (short distance), and it was limited to use in a laboratory scale device.

Therefore, the present inventor thinks that there is no way to accelerate the zeolite formation reaction in the coal ash and sodium hydroxide mixed liquid while adopting the batch system which can downsize the equipment. While conducting research on the improvement of the stirring blades provided, we adopted the method of increasing the number of these stirring blades, increasing the number of rotations, or introducing the counter rotating blades, but until obtaining efficient zeolite formation conditions. Didn't arrive.

[0005] In such mixing with the stirring blades, the flow of the mixed solution moves as a large lump in a kneading state due to the stirring performed in a predetermined reaction tank, and as a result, fine mixing cannot be obtained. Can be guessed.

The present invention has been made in view of the above problems of the prior art.
It is an object of the present invention to efficiently promote a zeolite-forming reaction in a raw material containing silicon and aluminum and an alkaline aqueous solution represented by sodium hydroxide in the production of an artificial zeolite by a batch method.

[0007]

In order to achieve the above object, the method for producing an artificial zeolite according to the present invention is represented by a raw material containing a predetermined amount of silicon and aluminum by a batch method and sodium hydroxide. In a method for producing an artificial zeolite by mixing an alkaline aqueous solution and performing a hydrothermal reaction while stirring in a reaction tank equipped with a stirring blade, the mixed solution in the reaction tank is prepared by transferring the mixed solution to a predetermined next step. A means was adopted in which the liquid was introduced into the reaction tank by a circulation pump and then returned to the reaction tank, and the circulation of the mixed solution was repeated for a predetermined time.

In the present invention, it is preferable that the circulation pump is an in-line mixer having a shearing function for the mixed liquid.

In the present invention, it is preferable that the mixed liquid is passed through a pipe having a predetermined small diameter in the circulation path by the circulation pump, and ultrasonic vibration is applied to the mixed liquid in the vicinity of the small diameter pipe. .

In the present invention, it is preferable that the mixed liquid is reheated in the circulation system path by the circulation pump.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a mixed liquid of a raw material containing silicon and aluminum in the reaction tank and an alkaline aqueous solution represented by sodium hydroxide (in this embodiment, coal ash and sodium hydroxide Mixed solution of
After being guided to the outside of the reaction tank by a circulation pump, it was returned to the reaction tank again, unlike the conventional stirring action in a large flow such as a stirring flow by a stirring blade,
Once the mixed solution is guided to the outside of the reaction tank in an accelerated state, separated from the stirring flow and then returned to the reaction tank again,
It can be combined with the agitation flow as a high-speed flow separate from the agitation flow, and the combination of the heterogeneous flows further enhances the mixing action as compared with performing the agitation action by a simple stirring blade, and as a result, the reaction is promoted. The processing time can be shortened. The circulation time of the mixed solution is 30 minutes to 18 minutes.
0 minutes is preferred.

In this case, when the circulation pump is an in-line mixer having a function of giving a shearing action to the mixed solution, a finely mixed state can be obtained in this pump, and the reaction is further promoted. Can contribute to. The in-line mixer referred to in the present invention is a vane type pump having a rotor and a stator and capable of imparting a shearing action to a carrier liquid, and is also known as a high shear mixer.
erson High Shear In-Line
Mixer (trade name) or the like can be used.

Further, in the present invention, the mixed solution is passed through a pipe having a predetermined small diameter in the circulation path by the circulation pump, and ultrasonic vibration is applied to the mixed solution in the vicinity of the small diameter pipe. In this case, if an ultrasonic wave generation source is arranged in the vicinity of this small diameter pipe, it is possible to reliably apply ultrasonic vibration to the mixed liquid that passes through it because of the small diameter pipe, and to prevent cavitation by ultrasonic waves. Due to the interfacial peeling action that is caused, the crystals that precipitate on the surface of the coal ash particles can be peeled off, and the crystallization reaction of zeolite can be further promoted.

Further, in the case where the mixed solution is reheated in the circulation path by the circulation pump, the temperature suitable for the reaction can be secured and maintained, and the reaction can be promoted. That is,
Usually, a means (steam heater) for overheating the mixed solution in the reaction tank or in the vicinity of the reaction tank is provided, but in the present invention, the mixed solution is once led out of the reaction tank in order to enhance the mixing efficiency. However, the temperature required for the reaction can be maintained by performing the reheating.

[0015]

The preferred embodiments of the method for producing an artificial zeolite according to the present invention will be described in detail below with reference to the drawings.
FIG. 1 is a flow chart showing an outline of a method for producing zeolite, and 1 is a batch-type reaction tank,
A raw material containing silicon and aluminum is mixed with coal ash and sodium hydroxide as an example of an alkaline aqueous solution typified by sodium hydroxide to react with each other, and steam heating means 2 is provided on a side portion thereof. Is placed, and the mixed solution inside is used at a temperature of 60 ° C. to 20 ° C.
It is controlled to be maintained at 0 ° C.

Reference numeral 3 denotes a circulation pump, and here, a high shear mixer (Silverson High S) is used.
A heart In-Line Mixer (trade name)) is used, and the mixed solution of the reaction tank 1 is once led out from the bottom of the reaction tank 1 and then returned to the upper part of the reaction tank 1 again in a circulation system passage 4. It is located inside. The circulation processing time of the mixed liquid by the circulation pump 3 is
Although it varies depending on various conditions, 30 minutes to 180 minutes is preferable.

Reference numeral 5 denotes an ultrasonic wave generation source, which is located in the circulation path 4, here, on the downstream side of the flow of the circulation pump 3. The portion of the circulation path 4 in which the ultrasonic wave generation source 5 is arranged is composed of a pipe having a relatively small diameter as compared with the other, here, the pipe having an inner diameter of 25 mm to 75 mm. Care is taken to ensure that vibration can affect the mixture.

In the circulation path 4, reheating means 6 is provided.
However, here, it is provided on the upstream side of the flow of the ultrasonic wave generation source 5, so that the temperature drop of the mixed solution due to the outside of the reaction tank 1 is compensated, and the mixed solution is in the required temperature range. Controlled as. Although steam similar to the above is used as the reheating means 6 here, an electric heater may be used. In addition, in FIG. 1, 7 is
The stirring blade is the same as the conventional one. Therefore, this detailed description is omitted here.

Example 1 25 kg of coal ash was mixed with 60 liters of an aqueous solution having a concentration of 2.5 mol to prepare a slurry, which was put into a reaction tank having a capacity of 120 liters, and the internal temperature of the reaction tank was 150 ° C.
The temperature was raised to, and the reaction was performed while maintaining the same temperature. After reacting for about 1 hour, the mixture was cooled to atmospheric pressure, the slurry was taken out, and the cake dehydrated by a filter press was analyzed by an X-ray diffraction apparatus. As a result, a peak derived from phillipsite, which is one kind of zeolite, was found. It was clearly recognized. Thus, the formation of zeolite was confirmed.

Example 2 A slurry in which an aluminum sash mold cleaning solution and sodium silicate No. 3 were adjusted and mixed so that the atomic ratio of silicon and aluminum was 1: 1 and the concentration of NaOH was adjusted to 2 mol. Was charged into a reaction tank, the temperature was once raised to 120 ° C., then cooled to 80 ° C., and reacted for about 2 hours. Thereafter, the cake dehydrated by the filter press was analyzed by an X-ray diffraction apparatus, and a peak specific to zeolite X was recognized. Thus, the formation of zeolite was confirmed.

[0021]

EFFECT OF THE INVENTION According to the method for producing artificial zeolite according to the present invention, the apparatus (plant) as a whole can be downsized and is excellent in heterogeneous flow which cannot be obtained only by conventional mixing with a stirring blade. Got a mixed action,
The reaction can be promoted, and the processing time can be shortened.

Further, in the present invention, when the circulation pump is an in-line mixer having a shearing ability with respect to the mixed solution, a shearing action is given to the mixed solution. In addition, it is possible to obtain a finely mixed state, further promote the reaction, and have the effect of increasing the processing capacity per unit time.

Further, in the case where the mixed liquid is passed through a pipe having a predetermined small diameter in the circulation system by the circulation pump and ultrasonic vibration is applied to the mixed liquid in the vicinity of the small pipe, the mixing is performed. There is an advantage that ultrasonic vibration can be surely applied to the liquid and the surface of the precipitated crystals on the surface of the coal ash particles can be peeled off, thereby further promoting the reaction. Other advantages of the present invention are as described in detail in the above-mentioned embodiments of the invention and the embodiments.

[Brief description of drawings]

FIG. 1 is a flow chart showing the principle of the method for producing zeolite of the present invention.

FIG. 2 is a flowchart showing the principle of a conventional zeolite manufacturing method.

[Explanation of symbols]

1 reaction tank 2 steam heating means 3 circulation pumps 4 Circulation system path 5 Ultrasonic generator 6 Reheating means 7 Stirring blade

Claims (4)

[Claims] 1. A hydrothermal reaction of a mixed solution of a raw material containing a predetermined amount of silicon and aluminum and an alkaline aqueous solution represented by sodium hydroxide in a batch system with stirring in a reaction tank equipped with stirring blades. In the method for producing zeolite by transferring the mixed solution to a predetermined next step, the mixed solution in the reaction tank is guided to the outside of the reaction tank by a circulation pump and then returned to the reaction tank again, A method for producing an artificial zeolite, wherein circulation of a mixed solution is repeated for a predetermined time. 2. The method for producing an artificial zeolite according to claim 1, wherein the circulation pump is an in-line mixer having a shearing function for the mixed liquid. 3. The liquid mixture is passed through a pipe having a predetermined small diameter in the circulation path by the circulation pump, and ultrasonic vibration is applied to the liquid mixture in the vicinity of the small pipe. The method for producing the artificial zeolite according to claim 2. 4. The method for producing an artificial zeolite according to claim 3, wherein the mixed solution is reheated in the circulation path by the circulation pump.