JPH04275916A - Production of pellet having zeolite composition and method for water processing - Google Patents

Abstract

PURPOSE:To offer the production method of pellet-type zeolite compsn. and the method to use that compsn. CONSTITUTION:The production method of pellet-type zeolite compsn. consists of a first process to granulate a fine powder comprising Al2O3-SiO2 material and its sintering agent, a second process to sinter and calcine the pellet by heating to change the mineral compsn. of the pellet into amorphous Al2O3-SiO2, a third process to change the obtd. pellet essentially comprising the amorphous Al2O3-SiO2 into zeolite in an alkali soln., and further a forth process to neutralize the zeolite pellet. Further, the obtd. zeolite is subjected to a treatment to add heavy metal ions such as Ag, Cu, Ni, Cr, etc., or to allow quaternary ammonium salt to be adsorbed on the pellet. The zeolite pellet obtd. by this method can be used as a filter material for water treatment.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a zeolite composition in the form of pellets.

0002

BACKGROUND OF THE INVENTION There are two types of zeolite: natural zeolite and synthetic zeolite. Natural zeolite is used as a soil conditioner, and synthetic zeolite is widely used as a catalyst, soap raw material, molecular sieve, etc. However, the quality of natural zeolite is inferior to that of synthetic zeolite, and it has not yet entered the field of synthetic zeolite. Furthermore, in the field of synthetic zeolite, although its quality is good, it is produced in the form of fine powder. Therefore, in order to use it in the fields mentioned above, it is necessary to agglomerate the fine powder by means such as granulation. A binder is usually required for agglomeration, but the contamination of this binder causes deterioration of the quality of the zeolite, which has been considered to be a drawback of agglomeration of synthetic zeolites.

0003

[Problems to be Solved by the Invention] The present invention provides a new method different from the existing method of once synthesizing zeolite and agglomerating it, and an agglomerated shape that can be applied to a wide range of uses. That is to say.

0004

[Means for Solving the Problems] The present invention provides (1) A
A first step of granulating a fine powder consisting of l2 O3 -SiO2 substance and its sintering aid, and heating the pellets from the first step to make the pellets have an amorphous Al2 mineral composition.
A second step of sintering and firing to form O3-SiO2, and amorphous Al2O3-S produced in the second step.
A method for producing zeolite pellets, which comprises a third step of converting pellets whose main composition is iO2 into zeolite in an alkaline aqueous solution (2) Fine powder consisting of an Al2O3-SiO2 substance and its sintering aid a first step of granulating the first step; heating the pellets of the first step; sintering the pellets so that the mineral composition of the pellets is amorphous Al2O3-SiO2;
The second step of firing and the amorphous Al2 generated in the second step
A method for producing zeolite pellets (3) comprising a third step of converting a pellet consisting of O3-SiO2 into zeolite in an alkaline aqueous solution, and a fourth step of neutralizing the zeolite pellet. Ag, Cu, Ni
The method for producing antibacterial zeolite according to item (1) or item (2) above, which comprises performing an addition treatment with heavy metal ions such as , Cr, etc.

(4) The above (1) characterized in that a quaternary ammonium salt is adsorbed onto the zeolite pellets.
) or (2), the method for producing antibacterial zeolite pellets.

(5) A water treatment method characterized in that the zeolite pellets obtained by the methods described in items (2) to (4) above are used as a filter medium for water treatment.

[0007]

[0008]

[Operation] Since fired pellets are produced in advance from a material with a composition and crystal structure that is easily converted into zeolite, this is converted into zeolite to produce pellet-shaped zeolite.
Unlike conventional methods, there is no deterioration in zeolite quality due to additives for agglomerating zeolite.

The present invention will be specifically explained below.

As already known, zeolite is N
a2 O・Al2 O3 ・nSiO2 ・xH2 O
It has the following composition, and its synthesis methods include the following.

(a) A synthesis method in which NaOH, water glass, sodium aluminate, colloidal SiO2, etc. are mixed in appropriate proportions and a hydrothermal reaction is caused.

(b) NaOH and Al2O3-S
A synthesis method by mixing iO2 with fine glass powder and causing a hydrothermal reaction in the same way as in (a).

[0013] The zeolite obtained by these methods is in the form of a slurry, and therefore requires some kind of agglomeration means and a binder necessary for agglomeration.

[0014] The present inventor has discovered that the above-mentioned Al2O3-Si
Various calcined kaolinite products were investigated as O2 glasses. And as a kaolinite calcined product, 800 to 1000
It has been found that those calcined at a temperature in the range of 0.99°C are most easily converted into zeolite. Furthermore, we have discovered that when NaOH or the like is used as a sintering aid, a sufficient sintered material can be obtained even if it is fired in the range of 800 to 1000°C, and a material that maintains sufficient strength can be obtained. Ta. Furthermore, by further adding NaOH etc., even if fired at high temperature,
Amorphous Al2O3-SiO suitable for zeolite production
It has also been found that a sintered material consisting of 2 can be obtained. Therefore, agglomerated zeolite pellets can be obtained by converting these pellets into zeolite according to a conventional method.

The process of the present invention for producing a porous zeolite body using kaolinite as a basic starting material is shown below.

First, in the first step, kaolinite and a water glass aqueous solution as a sintering aid are blended with a suitable binder, kneaded, and granulated. The raw material may be a mixture of kaolinite and NaOH, or a mixture of kaolinite and feldspar. These mixtures are kneaded using, for example, a mixer, and the kneaded product is granulated using a granulating device such as a pan pelletizer to agglomerate into pellets. In order to increase the sphericity of the pellets, an Eirich mixer, marmerizer, etc. may be used in the kneading and granulation process.

The second step is a firing step. The raw pellets produced in the previous process are produced in a rotary kiln at 800 to 1
000℃ or 1200-1300℃ for 30 minutes ~ 1
Baked for an hour. When the firing temperature is 800 to 1000°C, kaolinite alone or a small amount of water glass, NaO
In the case of raw materials with H added, the temperature is 1200-1300℃
In this case, the raw material conditions are kaolinite with NaOH and Na2
This is the case where the O content is 3 to 10% (this Na2
Feldspar powder can also be used as the O component). By adopting the above firing conditions, the main composition of the fired product is amorphous Al2O3
-SiO2, which is convenient for zeolite formation in the subsequent steps.

The third step is a zeolite formation step. Pellets made of amorphous Al2 O3 -SiO2 produced in the second step (hereinafter referred to as amorphous Al2 O3 -SiO2
It is called a pellet. ) is immersed in a boiling NaOH aqueous solution, and the surface of the amorphous Al2O3-SiO2 pellet is zeolized. A suitable NaOH concentration is 2 to 4N; if it is less than that, zeolite formation will not occur, and if it is more than that, hydroxy-sodalite, which is a different type of zeolite and has poor adsorption function, will be produced. phyllips with excellent adsorption function at 1 to 4N
ite is generated.

In this case, zeolite formation does not occur over the entire pellet, but occurs on its surface, and the zeolite formation area is approximately 1 mm deep. Therefore, in order to increase the degree of zeolization of the pellets, the particle size should be adjusted to 0.5
It is desirable to set the diameter to 1.0 mmφ.

The fourth step is a pretreatment step for antibacterial treatment and an antibacterial treatment step. The zeolite pellets converted into zeolite in the third step are made of Na-type zeolite and further have NaOH attached thereto. Therefore, as it is, it is inconvenient for use as a filter medium for water treatment, for example, and the above-mentioned neutralization step is necessary. In addition, when contacting with heavy metal ions for antibacterial treatment, if the pH becomes high, the heavy metal ions will be hydroxylated, causing a precipitation reaction, and sufficient ion exchange will not occur. is necessary.

As a means of antibacterial treatment, a sufficient ion exchange reaction occurs simply by immersing the zeolite pellets in an aqueous solution containing heavy metal ions, and therefore a immersion time of 10 to 60 minutes is sufficient.

[0022] Antibacterial zeolite pellets include silver type,
There are copper type, nickel type, etc., and it is preferable to perform ion exchange at a pH of 4.0 to 6.0. When the pH becomes less than 4.0, the zeolite pellets are destroyed by the acidic aqueous solution. Moreover, if it exceeds 6.0, heavy metal ions will precipitate. The method is to adjust the pH to 4.0 to 6.0 by adding mineral acid (hydrochloric acid or sulfuric acid).
During this period, an aqueous solution containing heavy metal ions (silver nitrate,
Copper sulfate, nickel sulfate, etc.) may be added.

[0023] Furthermore, it may be impregnated with an organic antibacterial material such as a quaternary ammonium salt. Such organic antibacterial materials are generally in solution form, so their uses are limited, but zeolite pellets can adsorb cationized quaternary ammonium ions, so they can be used as zeolite pellets with sufficient antibacterial properties. It can be said that it can withstand

[0024]

[Example] Example 1: Amorphous Al2O3-SiO2
Regarding the production example of pellets consisting of ■ Raw material conditions (A) Kaolinite alone.

(B) 10% NaOH to kaolinite
% added.

[0026] In the case of kneading (A), a suitable amount of water is added to fine powder of kaolinite, which is then kneaded in an Eirich mixer to form pseudo-granules.

In the case of (B), N is added to the kaolinite fine powder.
After adding aOH dissolved in an appropriate amount of water, it was kneaded and pseudo-granulated using an Eirich mixer.

(2) Granulation using a Marumerizer The kneaded and pseudo-granulated raw materials described above were again granulated and molded using a Marumerizer so that the particle size was 0.1 to 0.5 mmφ.

(2) Firing in a rotary kiln The Marumerizer granules described above were fired in a rotary kiln for 60 minutes. Firing at 900℃ and 125℃ for each raw material condition.
Firing was performed at 0°C.

■ Amorphous Al2O3 of fired pellets
Measurement of content The amorphous Al2O3 content was determined from its component composition (X-ray fluorescence analysis) and the mullite content determined by X-ray diffraction.

[0031] Amorphous Al2 O3 content = Al2 O3 content in pellets - 0.718 x (mullite content) Furthermore, it has been confirmed by X-ray diffraction that these fired products contain only glass and mullite. Therefore, the glass content was determined as follows.

Glass content = 100 - Mullite content The pellet composition determined in this way is shown in Table 1.

[0033]

[Table 1]

From the above, in the case of raw material condition (A), 900°C calcination is good for forming zeolite, and in the case of (B), 900°C or 1250°C may be used. However, in the case of (A), which was fired at 900°C, no sintering aids were included, so the strength after firing was very weak, and it collapsed during the subsequent process of turning into zeolite. . Conditions like (A) require a sintering aid such as water glass or water glass cullet. In that case, such collapse during zeolite formation can be prevented.

Example 2: Process of converting calcined pellets into zeolite and imparting antibacterial properties In the process of converting calcined pellets into zeolite, the calcined pellets (calcined at 1250°C under raw material condition (B)) were heated to ~100°C in an NaOH aqueous solution. immerse in it. The NaOH concentration of the NaOH aqueous solution at that time was 120 g/l. The immersion time was 5 hours. In addition, the NaOH aqueous solution is circulated during pellet immersion, and as much as possible fresh Na is kept near the pellet.
Care was taken to ensure that an OH aqueous solution was present. This means that the zeolite conversion of the pellets is complete. However, the entire pellet was not converted into zeolite, and the particle size was ~0.
It was found from the Na2O distribution state of EPMA that about 0.1 mm of its surface was converted to zeolite for every 5 mm.

When the zeolite treatment is completed, the pellets are taken out of the NaOH aqueous solution and subjected to a neutralization step. Since NaOH remained on the zeolite pellets that had been pulled up, neutralization and washing were performed to remove this and to make it antibacterial. i.e. 5%
A sulfuric acid aqueous solution was added to adjust the pH to 5.0. Next, it was washed with water again to remove sulfuric acid.

Next, in order to impart antibacterial properties to the zeolite pellets, the zeolite pellets are immersed in an aqueous solution containing various heavy metal ions or an organic antibacterial agent, and through a water washing and drying process, the antibacterial zeolite pellets are obtained. Manufactured.

Silver nitrate concentration in the case of silver zeolite pellets:
Zeolite pellets were added to a 50 g/l aqueous solution at a pH of
The sample was immersed for 30 minutes while being adjusted with a nitric acid aqueous solution so that the value was 5.0 to 6.0, and then washed with water.

[0039] In the case of copper zeolite pellets, copper sulfate concentration:
The zeolite pellets were immersed in a 75 g/l aqueous solution for 30 minutes while adjusting the pH to 5.0 to 6.0 with an aqueous sulfuric acid solution, and then washed with water.

In the case of nickel zeolite pellets, the zeolite pellets were immersed in an aqueous solution of 50 g/l of nickel sulfate for 30 minutes while adjusting the pH to 5.0 to 6.0 with an aqueous sulfuric acid solution, and then washed with water.

In the case of a quaternary ammonium zeolite porous material, the zeolite porous material was immersed in a 10% aqueous solution of Nikkanone PB (trade name) for 30 minutes while adjusting the pH to 5.0 to 6.0 with an aqueous hydrochloric acid solution. It was then washed with water.

[0042] The various antibacterial zeolite porous bodies as described above are manufactured and their antibacterial properties are applied as filter media for water treatment by arranging filter groups filled with the porous bodies in the following apparatus. show.

Example 3: Regarding the effect of using it as a filter medium for water treatment (a) When used for purifying an aquarium for live fish As shown in Figure 1, freshwater fish are kept in an aquarium 1 with a capacity of 500 liters. A filter with the following conditions was installed. In the figure, 2 indicates a circulation pump (1 liter/min), 3 indicates a filter group, and 4 indicates a circulation path.

Filter A: Ordinary filter material Filter B
: Zeolite pellets (Na-type zeolite pellets: zeolite pellets to which no antibacterial properties have been imparted) Filter C: Silver-type zeolite pellets Table 2 shows the changes over time in the quality of the circulating water in these cases.

[0045]

[Table 2]

[0046]

[Effects] As described above, since the present invention converts agglomerates into zeolites, pellet-like zeolites with excellent quality and strength can be obtained, and these zeolite pellets can be used as carriers for water treatment filters, catalysts, deodorization, and activated sludge. It has great industrial effects, such as being widely used.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an example in which the zeolite pellets of the present invention are used as a water treatment furnace material.

[Explanation of symbols]

Claims (5)

[Claims] Claim 1: A first step of granulating fine powder consisting of an Al2O3-SiO2 substance and its sintering aid;
A second step of heating the pellets from the first step and sintering and firing the pellets so that the mineral composition of the pellets consists of amorphous Al2 O3 --SiO2, and amorphous Al2 O3 --SiO2 produced in the second step. A method for producing zeolite pellets, comprising a third step of converting pellets having the main composition into zeolite in an alkaline aqueous solution. 2. A first step of granulating fine powder consisting of an Al2O3-SiO2 substance and its sintering aid;
A second step of heating the pellets from the first step and sintering and firing the pellets so that the mineral composition of the pellets consists of amorphous Al2 O3 --SiO2, and amorphous Al2 O3 --SiO2 produced in the second step. A method for producing zeolite pellets, comprising: a third step of converting the pellets into zeolite in an alkaline aqueous solution; and a fourth step of neutralizing the zeolite pellets. [Claim 3] Zeolite pellets contain Ag, Cu, and N.
3. The method for producing antibacterial zeolite according to claim 1 or 2, characterized in that the zeolite is subjected to an addition treatment with heavy metal ions such as i, Cr, etc. 4. The method for producing antibacterial zeolite pellets according to claim 1 or 2, characterized in that a quaternary ammonium salt is adsorbed onto the zeolite pellets. 5. A water treatment method, characterized in that the zeolite pellets obtained by the method according to claim 2, 3, or 4 are used as a filter medium for water treatment.