JPS58135121A - Manufacture of formed zeolite - Google Patents

Abstract

PURPOSE:To obtain a formed zeolite having excellent mechanical strength and high absorption capacity, by forming zeolite powder with a water-glass or clay binder in the presence of an amino acid. CONSTITUTION:Natural or synthetic zeolite powder is mixed with a water- glass binder such as sodium silicate or a clay binder such as kaolin and a water- soluble amino acid such as glycine, alanine, etc. the mixture is kneaded in the presence of water, formed, dried, and baked to obtain the objective formed zeolite. Since the strength of the formed zeolite is remarkably improved and the amount of the binder is reduced by the addition of amino acid, the decrease in the absorption capacity of the formed zeolite can be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a zeolite molded body, and its purpose is to produce a zeolite having excellent mechanical strength and good adsorption performance by molding zeolite powder to 1 wA by adding special additives. The purpose is to obtain a molded body.

Natural or synthetic zeolites are used in many industrial fields due to their adsorption properties, but they are rarely used in the form of small agglomerates or powders, and many In this case, zeolite is molded into a suitable granular form and fired to increase its mechanical strength. Generally, when producing a zeolite molded body, an inorganic clay material such as kaolin clay or bentonite clay is added, or additives and auxiliaries are used in combination. However, in this conventional method, in order to obtain sufficient strength, the amount of binder added increases, which remains in the molded product even after firing, which reduces the inherent adsorption capacity of zeolite, and conversely, it becomes insufficient. The problem was that the amount of binder added was insufficient to maintain sufficient adsorption ability, resulting in weak mechanical strength.

The present inventors conducted various studies to eliminate such drawbacks, and as a result found that the addition of amino acids was effective in forming zeolite, and based on this, the present invention was completed. - The present invention involves adding a water glass-based or clay-based binder and a water-soluble amino acid to zeolite powder, mixing in the presence of water, molding, and drying.

This is a method for producing a zeolite molded body, which is characterized by firing.

The zeolite used as a raw material in the method of the present invention may be either a natural product or a synthetic product, and is usually used in powder or granule form. As water glass binders, hydrated solutions of sodium silicate, potassium silicate, lithium silicate, etc. are used, and as clay binders, kaolin, bentonite, Il clay, etc. are used. The amount added is preferably 30% by weight or less based on the zeolite powder. Examples of water-soluble amino acids include glycine, alanine, aminobutyric acid, valine, leucine, serine, phenylamine, tryptophan, methionine, glutamic acid, etc. If one or more of these are dissolved in als in advance and added as an aqueous solution, they will be dispersed. is good and the kneading time can be shortened. The amount of amino acids added is 0 to zeolite powder.
．． 1 to 20% by weight, particularly 0.1 to 10% by weight is preferred; if it is less than 0.1% by weight, the effect of increasing the strength of the molded product due to the addition of amino acids is not sufficient, and if it exceeds 20% by weight, the strength of the molded product will deteriorate. adsorption capacity decreases.

In addition to the above binders and amino acids, if necessary, a dispersing agent,
A small amount of activated calcium carbonate, sodium oxalate, sodium stearate, etc. may be added as an extrusion aid.

The above mixture is mixed in the presence of water by about 0.5~
A homogeneous mixture can be obtained by kneading for 3 minutes. The amount of water added varies depending on factors such as the amount of amino acids and binder added, the type of zeolite material, etc., but it is usually preferable to maintain it at about 15 to 45% by weight based on the zeolite in order to obtain a uniform mixture. .

After extrusion molding the obtained mixture, the temperature is usually 100 to 150°C.
Perform pre-drying before and after to remove moisture adhering to the molded product.
Then, it is finally calcined at 350 to 700°C to obtain a zeolite molded product.

If the calcination temperature is higher than 700°C, the properties of the zeolide itself will be destroyed, so a temperature range of 7 (10'C or lower) is preferable.

In the method of the present invention, as mentioned above, the strength of the zeolite molded product is greatly improved by adding amino acids compared to the case without addition, and it is also possible to reduce the clouding caused by the use of the binder used in combination. Decrease in adsorption capacity can be minimized. Furthermore, since the strength of the molded product is increased, granulation is easier than in the case where no amino acid is added, and the particle surfaces are smoothed, which has the advantage of reducing wear due to mutual contact.

Example 1 To 2 kg of synthetic zeolite powder (powder with particle size finer than 200 mesh, type 4A zeolite) dried at 120°C, 700 μe of an aqueous solution in which 200 g of No. 3 sodium water glass (commercial product) and 64 g of glycine powder were dissolved was added. Mixing was performed for 30 minutes using an addition kneader. After cross-mixing, the above mixture was molded into a sphere with a particle diameter of 2 m using a molding machine, and then the molded product was dried at 120°C for 3 hours, and then subjected to 2WIl[ltR] at 600°C to obtain the final spherical molded body. Ta.

Comparative Example 1 A spherical molded body was obtained by carrying out the same operation as in Example 1 except that glycine powder was not added.

Example 2 400g of bentonite powder was used instead of No. 3 sodium water glass in Example 1! Add then 64g of glycine
A spherical molded body was obtained in the same manner as in Example 1 except that 700 mg of water was added and kneaded.

Comparative Example 2 A spherical molded body was obtained by carrying out the same operation as in Example 2 except that glycine powder was not added.

Example 3 120°C dry product 2- of natural zeolite powder (9 mordenite type zeolite powder with particle size finer than 200 mesh)
400g of bentonite powder and 128g of aminobutyric acid powder.
and mixed with a mixer, 800 ml of water was added, and mixed for 40 minutes using a kneader. After mixing, the above mixture was molded into a sphere with a particle size of 3 wI using a molding machine, and then the molded product was dried at 150°C for 2 hours and fired at 550°C for 2 hours to obtain a final spherical molded body. .

Example 4 A spherical molded body was obtained in the same manner as in Example 3 except that 256 g of alanine powder was added instead of the aminoacetic acid powder.

Example 5 (strength test, adsorption test) Examples 1 to 4. A load was applied to the molded product sample obtained in Comparative Example 1.2, and the load at the fracture point of the sample was measured (algebraic average value of the values for 100 samples) to determine the crushing strength.

Furthermore, the moisture adsorption capacity of each sample at 20° C. and 65% relative humidity was measured. The results are shown in Table 1.

As shown in Table 1, it can be seen that the molded bodies obtained by the method of the present invention have improved mechanical strength without a decrease in adsorption capacity compared to molded bodies obtained by the conventional method.

Applicant: Osaka Soda Co., Ltd. Agent: Patent attorney Toru Dojo

Claims (3)

[Claims] (1) Add water glass-based or clay-based binder and water-soluble amino acids to zeolite powder and mix in the presence of water.
A method for producing a zeolite molded body, which is characterized by molding, drying, and firing. (2) The production method according to claim 1, wherein the amount of water-soluble amino acid added is 0.1 to 20% by weight based on the zeolite powder. . (3) The manufacturing method according to claim 1 or 2, wherein the firing temperature is 350 to 700°C.