JPS5926919A - Preparation of crystalline aluminosilicate - Google Patents

Abstract

PURPOSE:To prepare a crystalline aluminosilicate composed of fine particles, in high yield and productivity, by mixing a concentrated aqueous solution of a silicate with an aqueous solution of an aluminate, gelatinizing and crystallizing the mixture, and at the same time, pulverizing the coarse crystals. CONSTITUTION:A concentrated aqueous solution of a water-soluble aluminate having a concentration of 30-70wt% is mixed with an aqueous solution of a water-soluble silicate having a concentration of 30-50wt% at a ratio to obtain the molar ratios (Na2O:Al2O3:SiO2:H2O) of (1.2-2.5):1:(1.5-3.0):(15-35), and the mixture is agitated, gelatinized and crystallized to obtain the crystals of aluminosilicate. In the above process, the system is heated at 60-110 deg.C after the completion of the gelation, and the mixture is recycled, pulverized and crystallized to obtain the slurry of fine aluminate crystals having a particle diameter of 3-5mu, atmost 10mu. The slurry is neutralized with an acid and spray-dried to obtain fine crystals of aluminate having excellent characteristics as the builder for a detergent in high yield.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing crystalline aluminosilicates. More specifically, the present invention relates to a method for producing a crystalline aluminosilicate slurry that is made of fine particles and contains few coarse particles.

In particular, it is an object of the present invention to provide a method for producing synthetic zeolite having excellent performance as a bilge for detergents in high yield and productivity at low cost.

Conventionally, it has been used as a builder for detergents or cleaning agents.

Phosphate has been used as the main builder due to its low cost and high calcium ion exchange capacity. However, in recent years there has been a problem of eutrophication in lake water, etc., and there is a shift from builders based on phosphate as a living body to builders based on aluminosilicate such as zeolite.

The general method for producing synthetic zeolites has been known for a long time. That is, a sodium silicate aqueous solution and a sodium aluminate aqueous solution are brought into contact with each other in the presence of an excess alkali.
It is produced by gelling and then heating for crystallization. For detergents and detergents, it is usually gelled and crystallized at a solid concentration of 30% or less.
The method used is to remove excess alkali by filtration and washing with water using filters such as Ilter Press and Rotary Filter Press. At this time, the alkali in the p liquid is concentrated, recovered, and reused. However, the v-filtration to remove this excess alkali and the concentration of the alkali recovery waste require a large amount of expense and equipment investment, which increases the cost of zeolite. Additionally, due to the rheological properties specific to zeolites, it is generally difficult to filter aluminosilicate suspensions with high solid content concentrations of 30% or more, and gelation usually occurs at solid content concentrations of 30% or less.・The reality is that it is crystallized.

The present inventors conducted various studies on methods that could simplify the process and produce at a low cost without relying on such methods, and found that by increasing the solid concentration during gelation, 4.
It was found that the production range of type A zeolite was expanded, and therefore the amount of excess alkali was required to be smaller than when synthesis was performed at a low concentration. From this, it has become clear that in carrying out the reaction, it is possible to reduce the amount of alkali used, neutralize it with an acid or an acidic salt, and convert it directly into a builder component for detergents.

In addition, the aluminosilicate slurry synthesized at a high concentration is directly introduced into a detergent slurry consisting of other cleaning active ingredients, auxiliary agents, etc., without the steps of filtration, water washing, and drying after the reaction, and is spray-dried to form a powder. It turns out that it is also possible to obtain synthetic detergents. Furthermore, when synthesized at a high concentration, less time is required for crystallization, and therefore the particle size of the zeolite particles produced tends to be smaller in crystallographic terms than when synthesized at a low concentration. understood.

The present inventors have found that producing aluminosilicates at high temperatures has various advantages as described above.
It has been found that when produced at high concentrations, it is difficult to control the growth rate of the crystals due to the high concentration of the system, and so-called nodules or agglomerates, which are clusters of fine grains, may occur. These nodules and grains are shown in Figure 1 (a).
As shown in the figure, it is a mass of fine particles,
Some have an average particle size of 10 to 20 microns.

It is extremely inconvenient for aluminosilicates used as builders for detergents and detergents to contain such coarse particles. That is, when an aluminosilicate of a certain particle size or more is used as a detergent builder, if water-insoluble particles adhere to clothes, there is a risk that the clothes will turn white after drying. Particularly in water-saving washing machines, adhesion to clothes is very noticeable, so zeolite containing such coarse particles cannot be used in practice, and large particles have a slow rate of ion exchange with calcium, so they cannot be used as detergent builders. is inappropriate, and requires a particle size of 3 to 5 microns, with a maximum of 10 microns, as shown in FIG. 1(b).

The present inventors have conducted extensive studies to find a method for producing a high-concentration aluminosilicate suspension by pulverizing or not producing the above-mentioned granules or nodules. During crystallization, the mixture is circulated from the mixing tank to a crushing device with high shear force, and is crushed by applying high shear force, and finally the average particle size of the aluminosilicate is reduced. The present invention was completed based on the discovery that it is possible to suppress the particle size to 8μ or less.

That is, the present invention provides a method for producing aluminosilicate by mixing a highly concentrated water-soluble silicate aqueous solution and a highly concentrated water-soluble aluminate aqueous solution, gelling them, crystallizing them, and simultaneously performing a crushing operation. This is what we provide.

On the other hand, the conventional method of pulverizing once crystallization is completed requires long-term operation of a powerful pulverizer such as a ball mill, sand mill, or attritor, which is disadvantageous. It is sufficient and extremely inefficient.

It is also possible to grind the gelled material before crystallization to a particle size of A, but since the gelled material has a property of being relatively agglomerated, it is difficult to prevent crystallization even if it is ground once. This is not preferable since it may cause aggregation during the process and form coarse particles.

The device used for pulverization in the present invention is not particularly limited, but a pulverizer usually called a colloid mill, a distingrater, or a homogenizer is used. Specific examples include a disper mill manufactured by Line Ironworks Co., Ltd., a homomic line mill manufactured by Tokushu Isoka Kogyo Co., Ltd., a homomic line mixer, and a homomic line mixer manufactured by Tokushu Isoka Kogyo Co., Ltd.

The shearing force in the above-mentioned crushing device is desirably one that provides a shearing force of 5 m/sec or more at the circumferential speed of the outer peripheral portion of the stirring blade or the rotating body.

The aluminosilicate slurry obtained by the method of the present invention has a solid content of 30 parts or more and can preferably be used for a long time, and is of great value both economically and from a process standpoint.

According to the present invention, the reaction in such a concentrated system is carried out at 60 to 70
This is carried out using a coulometric aqueous aluminate solution and a 30 to 50% by weight aqueous silicate solution.

It is not preferable to use an aqueous solution with a higher concentration or a solid substance of the above-mentioned salt as a starting material.

In order for the produced slurry to be used as it is or after being neutralized for use in detergent formulations, it is desirable that the amount of excess alkali be small, but fortunately, as mentioned above, the reaction in a concentrated system is not possible. Even if the amount of excess alkali is small, an aluminosilicate with excellent bilge performance can be obtained.

In particular, the composition of the rainwater solution mixture is Ha O
: AA O: 810. , : H,, O= 1.2
-2,5: G2 25 1.5-s, o: 15-35 is preferably prepared.

In the method of the present invention, gelation may be carried out batchwise or continuously. Further, the mixing method may be such that the water-soluble silicate aqueous solution is added to the water-soluble aluminate aqueous solution, or conversely, the water-soluble aluminate aqueous solution may be added to the water-soluble silicate aqueous solution overnight.

However, from the viewpoint of gel fluidity, it is most desirable to prepare an aluminosilicate gel in advance and add an aluminate aqueous solution and a silicate aqueous solution to it simultaneously.

In carrying out the present invention, the gel may be circulated and pulverized during gel preparation, but the effect is not so great, and when coarse particles in the gel are measured using a 50μ wet sieve method, it is usually 10%.
Some coarse particles are present.

Gelation is usually carried out at a temperature of 40 to 90°C, but it is necessary to adjust the gelation to prevent crystallization. If crystallization begins during gelation adjustment,
The crystallized core accelerates the crystallization rate, and the added water-soluble aluminate and water-soluble silicate crystallize immediately, forming solid aggregates, such as nodules or granules, that will remain stable even after pulverization. When gelation is completed at the 0th order K, which means that it cannot be easily pulverized, the temperature is raised to 60 to 110° C., and crystallization is carried out while circulating and pulverizing. The crystallization time is usually 15 to 120 minutes. The time required for crystallization mainly depends on the crystallization temperature, the gel concentration and the amount of excess alkali. If the crystallization time is too long or the temperature is too high, 4A will turn into hydroxysodalite, which has no ion exchange properties, so care must be taken.

Also, when carrying out the method of the present invention, the circulation speed to the crusher is:
It is desirable that the speed of crystallization is also fast. The crystallization speed depends on the crystallization temperature, gel concentration, excess alkali cap, amount of seed gel, etc., but normally the circulation speed is determined by the circulation of the gel or zeolite slurry in the mixing tank within the crystallization time. Specifically, it is desirable to be able to circulate within one hour, preferably within 20 minutes.

The mechanism of action of crushing at the time of crystallization in the present invention is to prevent the formation of strong aggregates by crushing and crushing in the transition region to crystallization where light aggregates are formed. On the other hand, crushing after crystallization is not easy because the above-mentioned extremely strong aggregates are formed.

The aluminosilicate slurry that has been pulverized and crystallized is cooled to 80° C. or lower to prevent it from becoming sodalite. Due to the excess alkali content in the cooled aluminosilicate slurry, detergents or detergents which, when used for detergents and detergents, should advantageously be prepared by neutralization with acids or acid salts. The component pressure of the cleaning agent can be changed.

The rice or acid salt used for the above-mentioned neutralization may be an inorganic substance such as carbon dioxide gas or a mineral acid such as sulfuric acid or hydrochloric acid.

However, anionic surfactants in the form of organic acids, such as fatty acids, citric acid, polyacrylic acid, maleic acid, or acids such as alkylbenzene sulfonic acids, paratoluene sulfonic acids, alkyl sulfates, alkyl ether sulfates, etc., may also be used for this purpose. It can be used for. Moreover, pH adjustment can be performed not only by one type of acid or acidic salt, but also by two or more types of acids or acidic salts.

The degree of neutralization is determined when the aluminosilicate suspension is measured as a 1st slurry, with a pH of 8.5 to 11.5, particularly a pH of 10.
A value of 11 to 11 is preferable because it exhibits excellent effectiveness as a detergent. It is important not to leave excess hydroxide in the aluminosilicate suspension when a powder detergent is produced by spray drying a slurry of the aluminosilicate suspension and other detergent ingredients. , is desirable in order to obtain good results in the powder physical properties of the product, particularly in terms of caking resistance, etc.

The suspension thus neutralized with an acid or an acidic salt is added directly to a slurry containing other detergent ingredients and spray-dried to obtain a powdered detergent.

Similarly, when mixing and gelling a water-soluble silicate and a water-soluble aluminate, it is also possible to carry out the present invention by adding a dispersant such as an acrylic acid oligomer to the gelled product in order to improve its fluidity. 0 Next, the structure and effects of the present invention will be explained in more detail by showing Examples and Comparative Examples, but the present invention is not limited to these Examples.

In the following Examples and Comparative Examples, coarse particles in aluminosilicate suspensions were examined using a test sieve with a fine diameter of 50 μm. The measurement method is to disperse the suspension well and accurately weigh 2f of the suspension.
After stirring for 5 minutes at 25℃ with 500 liters of water, add 500 liters of water.
Wash with water from Step d, and collect the residue through the wire mesh. Thereafter, this test sieve was dried in a dryer at 110° C., and then accurately weighed to calculate the amount of residue left on the sieve.

In addition, the particle size distribution is defined as the macroscopic fraction of microcrystalline particles.
&N0RTHRUP's photo-absorbing grain) K meter.

Example 1 Na2 was placed in a 200 A mixing vessel equipped with an external circulation system to a wet grinding device (Homo Mitsukline Mill LM-8 model manufactured by Tokushu Kika Kogyo Co., Ltd.) and a two-stage propeller agitator.
O/h, 1b20. /H20=1.06/1
/8 molar ratio of sodium aluminate aqueous solution 74~
and No. 5 sodium silicate aqueous solution (Na20 /
Sin,, / H2O = 1 / 3.15 / 22
．． 50 molar ratio) 99 K, and 500 Kg each
/Hr, and was added and mixed at a rate of 400Kr/Hr.

The mixing tank has a jacket for heating.
2Kf/ci2G of steam lowers the temperature inside the mixing tank to 7.
The temperature was raised to 0° C., and the mixture was sent and circulated through the opening valve at the bottom of the mixing container to a homomic line mill, a wet grinding device with discharge performance. The rotation speed of Homo Mitsukline mill is 3.60
At 0 rpm, the shear rate was 1'5 m/sea calculated from the circumferential speed of the internal turbine blades. The temperature was gradually increased and the line mill was operated until it reached 90°C. After 30 minutes, crystallization was complete and circulation was stopped. The gap between the turbine blades and the stator inside the homomic line mill was 0.5 positive.

The circulation to the homomic line mill was 30 A/min, and the number of circulations was calculated to be about 8 times.

When the coarse particles in the crystallized aluminosilicate @ suspension were measured using the 50μ wet sieve method described above, the particle size was 0.1.

Furthermore, it was confirmed that there were no nodules or granules when observed under a microscope. Particle size distribution is Lees
& Measured using a light scattering particle size analyzer manufactured by NORTHRUP. The volume average diameter was 4.9μ. The measurement results show the following particle spectra (Table 1).

1st surface area (μm) <31 100<22 99<1697<11 96<7.8 83% <5,5 79 <3,9 559J <2,8 29 Completed crystallization The aluminosilicate suspension was cooled to 70° C. and neutralized as a carbon dioxide slurry until the pH reached 10.6.

The aluminosilicate suspension after neutralizing excess alkali is
It was added directly to a detergent slurry containing other cleaning actives, builders, adjuvants, etc. and spray dried. The detergency and powder physical properties of the obtained powder detergent were the same as those of a powder detergent produced using a commercially available aluminosilicate. In addition, an adhesion test to clothing was conducted using a water-saving washing machine, but the adhesion of water-insoluble substances to clothing did not pose a practical problem.

Comparative Example 1 In the same manner as in Example 1, gelation and
Crystallization was performed.

After the crystallization was completed, the mixture was sent to a wet grinding device with discharge performance through an opening valve at the bottom of the mixing container, and circulated under the same conditions as in Example 1. After 30 minutes of circulation, the number of coarse particles in the aluminosilicate suspension was measured by the wet sieving method described above, and found to be 6 particles. The circulation and crushing were repeated for another 3 hours, but
When measured using a wet sieve method, there were still 3 sieve residues.

The particle size distribution after 3 hours of circulation was measured using a light scattering granulometer. The measurement results are shown in Table 2.

2nd surface <88 100 ratio <62 99 <44 96 <31 86 22 15 <16g5 <11 51 <7,8 59 <5.5 28 <3.9 16 < , 2.8 8 Comparative Example 2 Implementation After gelling and mixing at 50°C in the same manner as in Example 1, the mixed/gelling liquid is kept at 40 to 50°C and sent to a wet grinding device with discharge performance through the opening valve at the bottom of the mixing container. The gel was circulated under the same conditions as in Example 1, and after 50 minutes, the coarse particles in the gelled solution were measured by the wet sieving method described above, and there were still 4 particles. The mixture was circulated for an additional 3 hours, after which the circulation was stopped and the temperature was raised to 100°C to allow crystallization. The time required for crystallization was 20 minutes. When the coarse particles in the aluminosilicate suspension after crystallization are measured using the wet sieving method described above, it is still 1.
．． There was 5% sieve residue. The particle size distribution after 3 hours of circulation was measured using a light scattering granulometer. The measurement results are shown in Table 3.

5th surface <88 100qb <62 98 <44 96 <31 90 <22 80 <16 70 <11 58 <7.8 42 <5,5 51 ku 5゜9 18 <2.8 8 Comparative example 3 Comparative example After mixing, gelling, and crystallizing in the same manner as in 1, a portion of the aluminosilicate suspension was extracted and passed through Mycolloider (LSm manufactured by Tokushu Kika Kogyo) 10 times. The gap between the grinding wheels of Mycolloider was 0.5 m, and the number of rotations of the grinding wheels was such that when the coarse particles in the silicate suspension were measured by the wet sieving method described above, there were still 8 mm of sieve residue.

[Brief explanation of the drawing]

Figure 1 (a) is a microscopic sketch of a nodule formed during the synthesis of aluminosilicate @ suspension at a high concentration.
Figure (b) shows (a) of zeolite 4A particles that do not form nodules.
) is a similar figure. Applicant's agent Kaoru Furuya

Claims (1)

[Scope of Claims] 1. In producing a crystalline aluminosilicate by mixing and gelling an aluminate aqueous solution and a silicate aqueous solution, and subsequently performing hydrothermal crystallization, 30 to
An aqueous solution with a concentration of 70% by weight, or a silicate aqueous solution with a concentration of 50% by weight.
A method for producing a crystalline aluminosilicate, which comprises using a concentrated aqueous solution of ~50% by weight and simultaneously crystallizing and pulverizing to produce a crystalline aluminosilicate slurry. 2 The composition of the mixture obtained by mixing the aluminate aqueous solution and the silicate aqueous solution is Na2O:A720 in molar ratio.
．． : Sin□: H2O= 1.2~2,5:
1:1.5 to 3.0:1 s to 55. The method for producing a crystalline aluminosilicate according to claim 1. 3. A method for producing a crystalline aluminosilicate according to claim 1 or 2, wherein the pulverization is carried out using a pulverizer installed in a circulation system.