JPH075290B2 - Method for producing amorphous aluminosilicate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an amorphous aluminosilicate, and more specifically, it is inexpensive and has high oil absorption and high ion exchange properties. The present invention relates to a method for producing an aluminosilicate fine powder.

[Conventional technology and its problems]

Until now, amorphous hydrous silica called white carbon has been known as a highly oil-absorbing inorganic powder, and its properties have been utilized to develop many applications such as rubber fillers and papermaking. ing. However, since amorphous silica has a negative surface potential, when it is used, for example, as a filler for papermaking, it repels the negative surface potential of pulp and its yield is poor, which is not preferable. Further, the amorphous silica has a high porosity, surface hydroxyl groups, contains a large amount of adsorbed water, and the like,
The refractive index is also lower than that of other general silica, which is disadvantageous in that the opacity of the paper after printing is disadvantageous.

Further, as the highly oil-absorbing silica, dry silica called Aerosil is known, and it is used as a filler for rubber and plastics, but this is expensive and is used in the paper manufacturing industry. It is not suitable for use in fields requiring inexpensive raw materials.

Moreover, petal-like calcium silicate powder currently marketed under the trade name of "Florite" is 500 to 6
It has a very high oil absorption of 00 ml / 100 g, but it has the drawbacks of being expensive and causing pitch problems when used for papermaking.

The above-mentioned silicic acid and calcium silicate powder have, in addition to the above-mentioned drawbacks, a drawback of not having an ion-exchange capacity, and applications requiring a softening action of water, for example, a builder for detergents, a carrier for agricultural chemicals, Alternatively, it is not suitable for use to prevent scale generation due to Ca, Mg ions, etc. and contamination.

As a substance having a high ion exchange ability, a crystalline aluminosilicate called zeolite is well known, and in particular, synthetic zeolite 4A type is actually used in large quantities as a builder for synthetic detergents. However, zeolite itself is a densely packed crystalline particle of 1 to 10μ, and although it has many holes of molecular order, the retention of macroscopic voids related to oil absorption capacity is extremely small, and its oil absorption capacity is at most. Since it is about 60 ml / 100 g, high dispersibility in oil and water cannot be expected, and it cannot be used for applications requiring high oil absorption.

Further, the amorphous aluminosilicate powder marketed under the trade name of "Zeolex" has the same use as white carbon, etc., but has low oil absorption and low ion exchange capacity.

Various manufacturing methods of amorphous aluminosilicates such as "Zeolex" have been studied. For example, in JP-A-52-58099, an aqueous solution of alkali metal aluminate is added to an aqueous solution of alkali metal silicate.
Amorphous alkali metal aluminosilicate fine powder with physical properties of oil absorption of 75 ml / 100 g or more and ion exchange capacity of 200 mg CaCO ₃ / g or more by adding and mixing at a temperature of 70 ° C or less and keeping the reaction system at pH 10.5 or more A method of manufacturing is disclosed. However, depending on this method, 200ml / 100g
Amorphous aluminosilicates having the above high oil absorption cannot be produced. Further, JP-A-55-162418 discloses that an alkaline aluminate aqueous solution and an alkaline silicate aqueous solution are continuously supplied to a reaction system at a temperature of 60 ° C. or less, a particle size is large, and filtration / washing is easy. A method for producing an amorphous aluminosilicate having excellent ion exchange capacity is disclosed. However, this product is not manufactured for the purpose of increasing the oil absorption amount, and in fact, it is difficult to obtain a highly oil-absorbing amorphous aluminosilicate by this method. Further, JP-A-58-156527 discloses that
By adding the alkali metal aluminate salt solution and the alkali metal silicate salt solution to water at a temperature of 60 ° C. or lower,
Alternatively, by adding the alkali metal silicate solution to the alkali metal aluminate solution at a temperature of 60 ° C. or lower, the oil absorption is 200 ml / 100 g or more, and the cation exchange capacity has the same physical properties as those of various zeolites. A method of making a shaped aluminosilicate is disclosed. However, in this method, all the steps of the reaction are carried out at 60 ° C. or lower, and it is also necessary to use
Since Na ₂ O and Al ₂ O ₃ molar ratio Na ₂ O / Al ₂ O ₃ is a large value, it is difficult to oil absorption obtain amorphous aluminosilicate having the above characteristics 260 ml / 100 g.

The present invention is inexpensive, has an unprecedentedly high oil absorption capacity, and an object thereof is to provide an amorphous aluminosilicate having a high ion exchange capacity, in particular, an oil absorption amount of 260 ml / 100 g.
As described above, it is an object of the present invention to provide a method for producing an amorphous aluminosilicate having a physical property of ion exchange capacity of 100 mg CaCO ₃ / dry 1 g or more in a high yield.

[Means for solving problems]

As a result of intensive studies to solve the problems of the above-described conventional techniques, the present inventors have found that an alkali metal aluminate salt solution having a low alkali content and an alkali metal silicate solution have a low alkali content. The present invention has been completed by finding that the object can be achieved by reacting under special conditions.

That is, the present invention, the alkali metal aluminate aqueous solution and the alkali metal silicate aqueous solution are simultaneously added into water under strong stirring at a temperature of 15 to 60 ° C., and then heated at a temperature of 70 to 100 ° C. The present invention provides a method for producing an amorphous aluminosilicate characterized by treatment, and as a further preferred embodiment, an aqueous alkali metal aluminate salt solution,
The molar ratio of M ₂ O and Al ₂ O ₃ is M ₂ O / Al ₂ O ₃ = 1.0 to 2.0, and H ₂ O
And M ₂ O have a molar ratio of H ₂ O / M ₂ O = 6.0-500, which is a low-alkali alkali metal aluminate aqueous solution, in which the alkali metal silicate solution has a molar ratio of SiO ₂ and M ₂ O. SiO ₂ / M ₂ O = 1.0~
And a method for producing the above-mentioned amorphous aluminosilicate, which is an aqueous solution of alkali metal silicate having a molar ratio of H ₂ O and M ₂ O of 4.0 and H ₂ O / M ₂ O = 12 to 200. is there.

(However, M is an alkali metal) The raw materials for producing the highly oil-absorbing and highly ion-exchangeable amorphous aluminosilicate of the present invention are (a) alkali metal aluminate salt solution and (b) alkali metal silicate solution. If necessary, caustic alkali and water may be added to both of the above liquids to adjust the concentration / molar ratio. In the present invention, the alkali metal refers to one belonging to Group 1a of the periodic table, and sodium is usually advantageous.

Next, (a) alkali metal aluminate aqueous solution and (b) alkali metal silicate aqueous solution used in the present invention will be described.

(A) Alkali Aluminate Metal Salt Aqueous Solution As the alkali metal aluminate salt aqueous solution, a commercially available product may be used, but an aluminum source such as aluminum hydroxide or activated alumina (usually aluminum hydroxide) is heated and dissolved in alkali hydroxide. Alternatively, a high-concentration and low-alkali alkali metal aluminate salt solution may be first prepared, and then a mixture of the required amount of water and alkali hydroxide may be used. In this case, the preparation of the high-concentration solution is stabilized by heating and dissolving the aluminum source with alkali hydroxide and then rapidly cooling, but it is desirable to prepare a necessary amount of a lower alkali solution each time. Regarding the alkali metal aluminate aqueous solution used in the present invention, it is desirable that the molar ratio of M ₂ O (M is an alkali metal) and Al ₂ O ₃ is in the range of M ₂ O / Al ₂ O ₃ = 1.0 to 2.0. , 1.17 to 1.54 is particularly preferable, the concentration of Al ₂ O ₃ is preferably 1.0 to 30%, 5.0 to 2
The range of 0% is particularly preferable. This is because of manufacturing and physical properties.

(B) an alkali metal salt aqueous alkali metal silicate solution silicate, may be used commercially available products, the molar ratio of SiO ₂ and M ₂ O in the range of SiO ₂ / M ₂ O = 1.0~4.0 It is desirable to use one. The concentration of the aqueous solution is preferably 25% or less in terms of SiO ₂ concentration.

The present invention will be described in detail below.

First, water is put in a reaction tank and maintained at a temperature in the range of 15 to 60 ° C., and the above (a) alkali metal aluminate aqueous solution and (b) alkali metal silicate aqueous solution are simultaneously added under vigorous stirring. . Then the white precipitate slurry formed
Amorphous aluminosilicate having a strong higher-order structure is heated to a temperature of 70 to 100 ° C., preferably 90 to 100 ° C. and kept at that temperature for preferably 10 minutes or longer and 10 hours or shorter, preferably 5 hours or shorter. obtain. If the heat treatment is performed for more than 10 hours, aluminosilicate having a crystalline structure instead of an amorphous structure may be formed, which is not preferable. If this heat treatment is not performed, it is difficult to obtain an oil absorption of 260 ml / 100 g or more. The higher the temperature at the time of initial mixing, the higher the ion exchange property. However, if the initial temperature becomes too high, the oil absorption capacity of the obtained amorphous aluminosilicate becomes low. In order to obtain both physical properties, the initial temperature is preferably in the range of 15 to 60 ° C, particularly preferably in the range of 30 to 50 ° C. 70 ~
When heating at 100 ° C., strong stirring is not necessary. This heat treatment is preferably carried out while keeping the reaction system as it is, but may be carried out after partially concentrating by filtration or decantation. (A),
(B) When adding both, it is preferable to add them little by little rather than adding them all at once.

After the completion of the reaction, the produced particles may be used as a product slurry as they are, but usually, a filtration / washing step is performed to separate the mother liquor and remove excess alkali. Then, when dried, a very bulky and brittle mass is obtained, which easily disintegrates into fine powder to obtain the amorphous aluminosilicate of the present invention.

Amorphous aluminosilicate obtained by the method of the present invention has an unprecedentedly high oil absorption property, and has a high ion exchange capacity and a higher refractive index than conventional white carbon for papermaking, and is used as a filler for papermaking. If
It is effective because it retains the opacity of the paper after printing.

In addition, the amorphous aluminosilicate of the present invention and a surfactant can be mixed to obtain a detergent having excellent detergency.

Furthermore, it can be used as a filler for rubber, plastics, a carrier for agricultural chemicals, and the like.

The first feature of the production method of the present invention described above is that an alkali metal salt of low alkali aluminate, which has hitherto been considered to be a disadvantage, was used. In the present invention, for example, Na ₂ It is possible to use O / Al ₂ O ₃ = 1.18 (molar ratio). Moreover, this product and SiO ₂ / NaO ₂
= 3.2 (molar ratio) by using an alkali metal silicate, it is possible to reduce the amount of cleaning of excess alkali content and the like. Although such a reaction system has a low alkaline condition which has never existed before, the above-mentioned alkaline aluminate solution can be stably handled.

The second feature of the present invention is that the yield becomes maximum when the alkali metal aluminate salt solution and the alkali metal silicate solution have a Si / Al (molar ratio) of about 1. This indicates that the raw material can be used most efficiently. That is, it is considered that the ion exchange capacity is influenced by the number of oxygen-bonded bonds between the incorporated aluminum and silicon, and the number is the largest.
Since / Al = 1 (molar ratio), it means that if a product having this molar ratio is obtained in a high yield, a product having the physical properties aimed at by the present invention can be obtained in a high yield.

The third feature of the present invention is that the white precipitate slurry produced by adding and mixing both solutions is heat-treated at 70 to 100 ° C. When the slurry reacted under the conditions of the present invention is filtered, washed and dried without heat treatment by the method described in JP-A-55-162418, the oil absorption ability becomes extremely poor, and 200 ml / 10
It is difficult to obtain values above 0g. It is possible to obtain an oil absorption of 200 ml / 100 g or more under the condition of a large amount of alkali content in the reaction system, but it is still possible to obtain an oil absorption capacity of 260 ml / 100 g or more, except for the method of the present invention. Have difficulty.

[Action]

The effect of the production method of the present invention to bring about the effect peculiar to the present invention will be described in detail below with consideration.

Wet type hydrous silicic acid and other amorphous oil absorbers have a model in which spherical primary particles with a particle size of several tens of Å to several hundred Å are polymerized into a tuft of grapes to a size of several thousand Å. Has been submitted. It is considered that these aggregated particles further form third-order and fourth-order flocs (soft aggregates, aggregate structures).
The same model is basically applied to the amorphous aluminosilicate of the present invention. Considering the basic factors related to oil absorption capacity, it is the particle size of primary particles and secondary particles when they aggregate, the porosity determined by the coordination number, and the This is a correlation between the particle size at the time of separation / drying, the contraction force determined by the surface tension of the filled liquid, and the strength of the aggregate structure. That is, since the oil absorption capacity is evaluated by measuring the final isolated / dried powder, no matter how large the porosity of the aggregate particle structure in the slurry is, the dried particles are dried. If the shrinkage force at that time is such that a structure with a large porosity can be destroyed, the oil absorption capacity will not eventually increase.

First of all, the aggregate structure with a large porosity is determined by the coordination number of the primary particles. Generally, the smaller the particle size, the smaller the coordination number and the larger the porosity. It depends on the conditions. Unlike the case of crystal growth, the primary particle size becomes smaller as the concentration becomes lower and the addition speed becomes faster, and the particle size becomes uniform as the stirring is stronger.
Therefore, if particles are deposited in a short time at a low concentration, aggregate particles with a large porosity should be formed.

Secondly, the shrinkage force during drying becomes a problem. This contraction force increases as the void radius decreases and the surface tension of the liquid increases. Therefore, regarding the particle size, it is understood that there is a maximum value in relation to the shrinkage force.

In the present invention, an unprecedentedly high oil absorption capacity is obtained because it is possible to generate relatively uniform primary particles, and the aggregate structure can be strengthened while reflecting the primary structure having a large porosity. it is conceivable that. That is, it is considered that the simultaneous addition of the raw materials makes the particle size and composition uniform throughout the reaction. Also, under reaction conditions of 60 ° C. or lower, a large number of hydroxyl groups on the particle surface exist, and it can be said that the particles are soft particles. Therefore, it is particularly weak against contraction force. On the other hand, when heat treatment is performed, the silanol bond is changed to a siloxane bond while maintaining the coordination state, and the aggregate structure is strengthened. The particles deposited at high temperature from the beginning have the surface already covered with siloxane bonds, and the bonds at the gathering points are weakened, resulting in a brittle state rather than shrinkage force. Thus, it is considered that the aggregate particle structure at the time of heat strengthening becomes the largest and strong when the production method of the present invention is adopted.

〔Example〕

The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, the measuring method of the measured value in an Example and a comparative example is shown next.

(1) Oil Absorption The sample was crushed in a mortar and measured by the oil absorption measurement method of JIS K 6220.

(2) Loss on ignition Ignition is performed in advance at 800 ° C for 1 hour, and a few grams of the sample is put into a magnetic crucible that has reached a constant weight in a desiccator and weighed accurately. Then, ignite in an electric furnace at 800 ° C for 1 hour, and accurately weigh the weight that reached a constant weight in a desiccator to reduce the ignition loss by weight%.
I asked for.

(3) Ca ion exchange capacity 0.1 g of the sample was accurately weighed in terms of anhydride calculated from loss on ignition, added to 100 ml of calcium chloride solution (CaCO ₃ 500 ppm), and stirred at 25 ° C for 15 minutes, Perform suction filtration with two sheets of Toyo Filter Paper No. 5c, take 50 ml of the filtrate, and remove Ca in the filtrate.
TA titration was performed and the Ca exchange capacity of the sample was determined from the value.

Incidentally, the calcium ion exchange ability is evaluated to be rather high when the washing of the powder is insufficient. That is, when excess alkali ions remain, they react with CO ₂ gas in the air to form a carbonate, which apparently has a high Ca ion exchange capacity. Therefore, the measurement sample must be thoroughly washed.

(4) X-ray diffraction CuK using Rotaflex pl200 (trade name) of Rigaku Denki Co., Ltd.
It was measured using _α rays.

Example 1 Sodium aluminate solution (Na ₂ O 8.34% by weight, Al ₂ O ₃ 1
42.44 g of 1.60 wt%, Na ₂ O / Al ₂ O ₃ = 1.18 (molar ratio) and sodium silicate solution (Na ₂ O 3.8 wt%, SiO ₂ 11.6 wt%, SiO ₂ / Na ₂ O = 3.15 (mol) Ratio)) 50g at the same time diameter 45mm
The mixture was added to 200 g of ion-exchanged water at 30 ° C. with a microtube pump while stirring with a magnetic stirrer piece of 1500 rpm. Immediately after addition is complete
Heating was carried out at 100 ° C. for 1 hour, followed by filtration and washing.
The obtained wet cake is dried at 110 ° C until a constant weight is obtained,
By pulverizing, 12.8 g of X-ray amorphous aluminosilicate fine powder was obtained. The yield was 93%.
This powder has an oil absorption capacity of 294 ml / 100 g, ion exchange capacity of 131 CaCO ₃ mg.
The physical property was / 1 g.

Example 2 In the same operation as in Example 1, the amount of ion-exchanged water was changed to 15
Amorphous aluminosilicate fine powder to 0g 12.5g
(Yield 91%) was obtained. The oil absorption capacity of this product is 281 ml / 100 g,
The ion exchange capacity was 143 CaCO ₃ mg / 1 g.

Example 3 Sodium aluminate solution (Na ₂ O 5.25% by weight, Al ₂ O ₃
67.44 g of 7.30 wt%, Na ₂ O / Al ₂ O ₃ = 1.18 (molar ratio) and sodium silicate solution (Na ₂ O 2.71 wt%, SiO ₂ 8.29 wt%, SiO ₂ / Na ₂ O = 3.15 (mol) Ratio)) 70g at the same time at 35 ℃, 10
Amorphous aluminosilicate fine powder was obtained by adding to 0 g of ion-exchanged water under the same conditions as in Example 1 and performing the subsequent operations at the same time. The oil absorption capacity of this product is 265 ml /
The ion exchange capacity was 100 g and 154 CaCO ₃ mg / 1 g.

Example 4 Sodium aluminate solution (Na ₂ O 11.45% by weight, Al ₂ O ₃
11.07 wt%, Na ₂ O / Al ₂ O ₃ = 1.7 (molar ratio) 44.44 g and sodium silicate solution (Na ₂ O 3.8 wt%, SiO ₂ 11.6 wt%, SiO ₂ / Na ₂ O = 3.15 (mol) Ratio)) was added into ion-exchanged water at 30 ° C. and 150 g in the same manner as in Example 1, and the subsequent operations were also performed at the same time to obtain amorphous aluminosilicate fine powder. The oil absorption capacity of this product was 280 ml / 100 g, and the ion exchange capacity was 165 CaCO ₃ mg / 1 g.

Comparative Example 1 In the same operation as in Example 1, an amorphous aluminosilicate was obtained without heat treatment at 100 ° C. for 1 hour.
The oil absorption capacity of this product was 45 ml / 100 g, and the ion exchange capacity was 78 CaCO ₃ mg / 1 g.

Comparative Example 2 In the same operation as in Example 2, an amorphous aluminosilicate was obtained without heat treatment at 100 ° C. for 1 hour. The oil absorption capacity of this product is 50ml / 100g, and the ion exchange capacity is 63C.
It was aCO ₃ mg / 1 g.

Comparative Example 3 In the same operation as in Example 3, an amorphous aluminosilicate was obtained without performing heat treatment at 100 ° C. for 1 hour. The oil absorption capacity of this product is 50 ml / 100 g, and the ion exchange capacity is 66 CaCO ₃ mg.
It was / 1g.

Comparative Example 4 In the same operation as in Example 4, an amorphous aluminosilicate was obtained without heat treatment at 100 ° C. for 1 hour. The oil absorption capacity of this product is 165 ml / 100 g, and the ion exchange capacity is 88 CaCO ₃ m.
It was g / 1g.

〔The invention's effect〕

As specifically shown in Examples, the amorphous aluminosilicate obtained by the method of the present invention is
It has an unprecedentedly high oil absorption property, and has a high ion exchange capacity and a higher refractive index than conventional white carbon for papermaking, so it can be said to be an inorganic material having more functionality than conventional white carbon. . In addition, the loss of the raw material system can be suppressed to a minimum, and the production cost can be reduced because the reaction is low pressure and the reaction is normal pressure. Therefore, the amorphous aluminosilicate of the present invention can be used as a filler for paper, especially lightweight paper, gas,
It can be considered to be applied to many fields of application such as adsorbents for perfumes, detergents, toothpaste additives, sebum control agents, agricultural additives, paint additives, and ceramic binder additives.

Claims (2)

[Claims] 1. An alkali metal aluminate aqueous solution and an alkali metal silicate aqueous solution are simultaneously added into water under strong stirring at a temperature of 15 to 60 ° C., and then heated at a temperature of 70 to 100 ° C. A method for producing an amorphous aluminosilicate, which is characterized by performing a treatment. 2. An aqueous solution of an alkali metal aluminate is M ₂ O.
And Al ₂ O _{3 have} a molar ratio of M ₂ O / Al ₂ O ₃ = 1.0 to 2.0, and H ₂ O and M ₂
Molar ratio of ₂ O is a low alkali aluminate alkali metal salt solution which is a H ₂ O / M ₂ O = 6.0 to 500, alkali metal salt solution silicate, the molar ratio of SiO ₂ and M ₂ O is SiO ₂ / M ₂ O = 1.0 to 4.
An alkali metal silicate aqueous solution having a molar ratio of H ₂ O to M ₂ O of 0 to 0 and H ₂ O / M ₂ O = 12 to 200.
A method for producing an amorphous aluminosilicate according to the item.
(However, M is an alkali metal)