JPH02160616A - Production of formed article of type-a zeolite - Google Patents

Abstract

PURPOSE:To produce a formed article of type-A zeolite having large adsorption capacity without lowering the strength by calcining a formed article of sodium type-A zeolite crystal powder containing a binder and contacting the calcined product with a solution containing an exchangeable metal ion. CONSTITUTION:Powder of sodium type-A zeolite crystal is compounded with 5-15 pts.wt. (based on 100 pts.wt. of the powder) of a binder and the obtained mixture is formed and calcined. The calcined product is made to contact with a solution containing an exchangeable metal ion to effect the ion-exchange and obtain the objective formed article of type-A zeolite. The binder used in the above process is an inorganic binder (e.g. bentonite), an organic binder (e.g. methylcellulose), etc. The formed article of sodium type-A zeolite is preferably dried at a low temperature (100-200 deg.C) to prevent the mutual adhesion. The calcination is preferably carried out at a temperature as high as possible in a range giving no influence on the crystal structure of zeolite (e.g. at >=400 deg.C).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a zeolite molded body used as an adsorption/separation agent, an ion exchange agent, a catalyst, etc.

More specifically, it is a method for producing a molded A-type zeolite that has a significantly high absorption capacity, can relatively easily achieve a high ion exchange rate, and has high strength, while significantly reducing ion exchange costs. I propose a method to do this.

[Prior Art] The pore size of type A zeolite is determined by the type of metal ion; for example, the pore size is about 4 angstroms for sodium ions, and about 3 angstroms for potassium ions.

For calcium ions, it is about 5 angstroms. Ion exchange with ions from group 1 or group II of the periodic table is performed at an appropriate ion exchange rate to obtain the desired pore diameter A! 12 zeolites can be obtained. Zeolites with controlled pore diameters are used in a wide range of applications such as absorption and separation agents and catalysts. For example, type A zeolite with calcium ion exchange and pore size controlled to 5 angstroms,
The PSA adsorption separation method is widely used to separate oxygen and nitrogen gases in the air. When zeolite is used for these purposes, particularly for industrial applications, it is most often used as a molded body with a certain strength for packing into columns.

Conventionally, zeolite formation ((2) is made by first ion-exchanging the desired ions with zeolite crystal powder to create zeolite crystal powder with the pore size controlled in advance, adding a binder such as clay to it, and then mixing and kneading it. It is manufactured by molding using a regular molding machine.

The amount of the binder is A(2) 20 parts by weight or more, preferably 25 parts by weight or more per 100 parts by weight of the zeolite crystal powder. The zeolite molded body thus formed is subsequently fired at a high temperature. This calcination is carried out at a temperature that does not break the zeolite crystals and provides sufficient strength to the molded body, specifically at a temperature of 450 to 800''C.

On the other hand, in Japanese Patent Application Laid-open No. +1/f 55-104913, A-type zeolite crystal powder is molded and the resulting molded body is subjected to ion exchange treatment to produce A-type zeolite which has both high suction ability and strength! - A method of manufacturing a molded body has been proposed. However, the publication states that zeolite 1
Only a method using 25 parts by weight of binder per 00 parts by weight is shown.

As for the amount of binder used, the above is true! (
′! This is no different from the method of exchanging ions beforehand.

[Problems to be Solved by the Invention] An object of the present invention is to provide a method that can produce larger A-type zeolite molded bodies such as suction plates without reducing strength. be.

In the past, efforts have been made to reduce the binder content in order to produce larger zeolite compacts of 4'j '8 In. However, reducing the binder content has been extremely difficult in the coating industry because it leads to a decrease in strength and moldability. Therefore, A
ffl zeolite molded body is zeolite crystal powder 100
The binder is contained in an amount of about 2 (1 m part to 30 parts by weight) based on the weight part.

[Means and effects for solving the problem] The present inventors molded sodium A type zeolite crystal powder, and then
If the ion exchange method is used, the amount used is less than 15 parts by weight per 100 parts by weight of the above powder, which is much smaller than the conventionally known amount, and it can be used for practical purposes (with a strength that can be reduced by 3%). The present invention was achieved by producing 9 pieces of powder and discovering scales. However, if the amount used is too small, the strength of the molded product obtained will be insufficient. It is necessary to use 5 parts by weight or more per part.

In other words, the gist of the present invention is that when producing an Au zeolite molded body, after blending 5 to 15 parts by weight of a binder per 100 parts by weight of sodium A-type zeolite crystal powder and molding the powder, ion exchange by calcination and contact with a solution containing exchangeable metal ions;
A method for producing an AQ zeolite molded body. The details will be explained below.

The sodium A-type zeolite crystal powder to be preformed in the present invention may be obtained by a known method for producing sodium A-type zeolite crystal powder. The sodium A-type zeolite crystal powder is mixed with 5 to 15 parts by weight of a binder, kneaded, and molded. As a binder, for example, bentonite, diatomaceous, kaolin,
Inorganic binders such as plastic ball clay and bentonite earth; crystalline cellulose such as methyl cellulose, carboxymethyl cellulose, and hydroxymethyl cellulose; and H-organic binders such as molasses may be used alone or in combination.

The shape of the molded body may be granular, pellet-shaped, spherical, or the like.

Next, the molded strium A type zeolite molded body is
Prevent them from hitting each other! =100-200
It is best to dry at a low temperature of ℃.

The dried and shape-adjusted sodium-Au zeolite molded body is heated and fired. Regarding the firing conditions, in order to impart strength to the molded product, it is desirable to perform the firing at a temperature as high as possible, for example, at a temperature of 400° C. or higher, without changing the zeolite crystal structure.

This calcined sodium-Au zeolite molded body is brought into contact with a liquid containing metal ions, usually metal ions belonging to Group 1 or Group II of the periodic table, to perform ion exchange. Ion exchange methods include batch methods, column methods, and the like, and any of these methods may be employed. In the present invention, since ion exchange is performed after molding, it is possible to perform .r-on exchange by a column method, and the ion exchange cost can be significantly reduced. Furthermore, according to the present invention, an ion exchange step for zeolite crystal powder is not necessary, so
It is also possible to prevent a decrease in yield due to zeolite crystal powder being washed away during washing, further promoting the effect of reducing manufacturing costs.

The column method, which is an economical ion exchange method, will be explained below as an example.

There is no limit to the concentration of the salt solution used for ion exchange. However, when considering productivity and the material of the equipment, 0.5 to 2. O
Concentrations in the range of N are preferred. Further, there is an appropriate flow rate range for the solution flow rate depending on the column shape and size. The direction of flow of the salt solution is not particularly limited. However, for example, when ion-exchanging a molded sodium A-type zeolite with a potassium salt solution, it is preferable to flow the potassium salt solution from the bottom of the tower to the top, and when ion-exchanging with a calcium salt solution or lithium salt solution, A preferred method is to flow a calcium salt solution or a lithium salt solution from the upper part of the tower to the lower part. Regarding the temperature, it is possible to perform the process at room temperature, but heating it to about 90°C is effective in shortening the time to reach ion exchange equilibrium, and in terms of time, it is also possible to perform the process at room temperature. It is also effective.

The ion-exchanged A-type zeolite molded body is washed after extracting the liquid from the column, or while directly replacing the liquid in the column in washing 11, or is dried without washing. Drying is carried out under conditions sufficient to remove attached moisture by ion exchange or washing. This operation is carried out under relatively mild conditions, but the operation for removing the water attached to the A-type zeolite molded body and the removal of the water absorbed by the A-type zeolite crystals are carried out separately. There is also. For example, in order to remove attached moisture, it is carried out at a temperature in the range of 80 to 120℃, and in order to further remove the moisture absorbed by type A zeolite crystals, it is carried out at a temperature in the range of 300 to 120℃.
Heated at a temperature of 800°C. If these operations are performed under reduced pressure, the temperature may be lower and the humidity may be lower, or the time may be reduced.

In addition, by circulating dry air, etc., it is possible to
・You can get the same effect as ■.

[Effects of the Invention] In the method for producing a zeolite molded body of the present invention, sodium A-type zeolite crystal powder, which has relatively good moldability and good compatibility with the binder, is molded in advance, so that the binder can be used without reducing the strength. content is reduced, resulting in increased adsorption capacity. By performing ion exchange to control the pore size after molding the sodium A-type zeolite crystal powder, ion exchange using the flow method becomes possible, reducing the production cost without increasing the adsorption capacity. Large A-type zeolite molded bodies can be produced.

[Example] Example 1 Crystalline powder (approximately 100 mesh) of Thorium A-type zeolite (Zeolum A4, manufactured by Tosoh Corporation) sold by 1j.
100 parts by weight and 10 parts of domestic kaolin clay are mixed, water is added and kneaded, passed through a die with a hole diameter of 1.5 mm, and extruded to form a molded product with a length of approximately 5 to 15 m. And so. This molded product was left to dry in a ventilation dryer at 110°C for 12 hours, and then fired in a furnace at 550"C for 2 hours. The fired molded product had a diameter of 65 mm and a length of 800 m.
Approximately 1.3 kg of 1N calcium chloride aqueous solution was packed into a packed tower of n, heated to 70°C, and passed from the top to the bottom of the packed tower at a flow rate of 40 ml/min. - Ion exchanged sodium ions in the molded body into calcium ions. After ion exchange, the calcium chloride aqueous solution remaining in the packed tower is drained, and 1
31 distilled water was passed through and washed. This A-type zeolite molded body was left to dry at 110'C for 12 hours in a ventilation dryer. The .r-ion exchange rate of the obtained A-type zeolite molded body was measured by atomic absorption spectrophotometry and found to be 88.8.87.7.88 at the top, middle, and bottom of the packed tower, respectively.
It was 0%. (Test R') A) Example 2 Approximately 1.3 kg of the sodium A type zeolite molded body prepared in the same manner as in Example 1 was packed into a packed tower with a diameter of 65111 and a length of 800 am, and an aqueous solution of IN calcium chloride was added. The solution was heated to 70° C. and passed from the top to the bottom of the packed column at a flow rate of 80 ml for 7 minutes to perform ion exchange of sodium ions in the sodium A type zeolite molded body into calcium ions. After washing and drying in the same manner as in Example 1, the ion exchange rate was measured by atomic absorption spectrometry, and the results were 87.5.89.5 at the top, middle, and bottom of the packed tower, respectively.
．． It was 88.9%. (Sample B) Example 3 Approximately 1.3 kg of the sodium A type zeolite molded body prepared in the same manner as in Example 1 was packed into a packed tower with a diameter of 65 mm and a length of 800 mm, and an aqueous solution of IN calcium chloride was added. 70
C. and flowed from the top of the packed tower downward at a flow rate of 160 ml/min to perform ion exchange of thorium ions in the sodium A 442 zeolite molded body into calcium ions.

After washing and drying in the same manner as in Example 1, the ion exchange rate was measured by atomic absorption spectrophotometry.
That's it at the bottom! It was 89.6.89.4.89.3%. (Sample C) Example 4 A molded sodium A zeolite prepared in the same manner as in Example 1 was immersed in an IN aqueous solution of calcium chloride heated to 80°C for about 4 hours, stirred, and dissolved in sodium A 4 (
2. Sodium ions in the zeolite molded body were ion-exchanged with calcium ions.

After ion exchange, solid-liquid separation was performed and washed with distilled water. The same ion exchange operation was performed three times in total.

As a result of measuring the ion exchange rate by atomic absorption spectrometry,
It was 91.0%. (Sample D) Comparative Example 1 Crystalline powder (approximately 100 mesh) of commercially available sodium A-type zeolite (Zeolum A4, manufactured by Tosoh Corporation>1) 2k
g of calcium chloride aqueous solution heated to 80°C, 2
81 for about 4 hours and stirred to perform ion exchange of sodium ions into calcium ions. After ion exchange, solid-liquid separation was performed and washed with about 101 g of distilled water. The same operation was performed three times in total. The ion exchange rate was determined by atomic absorption spectrometry. The result was 91.0%. 100 parts by weight of this A-type zeolite crystal powder ion-exchanged into calcium type and 2 parts Off of the clay-based binder used in Example 1 were mixed, mixed with water, and passed through a die with a pore size of 1.5 mm. Then, it was extruded to form a molded product with a length of about 5 to 15 dragons. This molded product was left in a ventilation dryer at 110° C. for 12 hours, and then fired in a furnace at 550° C. for 2 hours. (Sample E) Comparative Example 2 A that underwent calcium ion exchange in the same manner as Comparative Example 1
100 parts by weight of type zeolite crystal powder and 1 part of viscous binder
5 fff parts, water is added and kneaded, and the pore size is 1.5 fff.
Pass through a 5-fin die and extrude to a length of about 5~
It was made into a molded product of 15 dragons.

This molded product was left at 110°C for 12 hours in a ventilated drying product.
Further, it was fired in a furnace at 550°C for 2 hours.

(Sample F) Comparative Example 3 A that underwent calcium ion exchange in the same manner as Comparative Example 1
Mix 1 part of type zeolite crystal powder 1100ff and 10 parts by weight of clay-based binder, add water and knead to obtain a pore size of 1.5
When an attempt was made to extrude the material by passing it through an a+m die, extrusion molding was impossible.

The above is the crushing strength of samples A-F.

Comparing the nitrogen suction capacity and calcium chloride basic unit,
Shown in the table. Here, the crushing strength is the ql average value of the strength of 100 molded bodies measured using a Honya type hardness tester. The nitrogen absorption capacity is determined by the ffi method at a temperature of -10°C and a nitrogen pressure of 700 Torr. The basic unit of calcium chloride is the value obtained by converting the amount of calcium chloride aqueous solution used for ion exchange into the weight of anhydrous calcium chloride salt, and dividing that value by the dry weight of the sodium A-type zeolite molded body.

table

Claims (1)

[Claims] (1) When producing a type A zeolite molded body, after blending 5 to 15 parts by weight of a binder per 100 parts by weight of the powder with sodium type A zeolite crystal powder and molding, the mixture is calcined and exchangeable metal ions are formed. A method for producing a molded A-type zeolite, the method comprising performing ion exchange by contacting with a solution containing A-type zeolite.