JPH064484B2 - 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.

Recently, petal-like calcium silicate powder marketed under the trade name of "Florite" is 500-600.
It has a very high oil absorption of ml / 100g, 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, crystalline aluminosilicate called zeolite is well known, and in particular, synthetic zeolite 4A type is actually used in large quantities at present 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 an alkali metal aluminate is added to an aqueous solution of an alkali metal silicate.
Addition and mixing at a temperature of ℃ or below, keeping the reaction system at a pH of 10.5 or above allows oil absorption of 75 ml / 100 g or above, ion exchange capacity of 2
A method for producing an amorphous alkali metal aluminosilicate fine powder having a physical property of 00 mg CaCO ₃ / g or more is disclosed. However, this method cannot produce an amorphous aluminosilicate having a high oil absorption of 200 ml / 100 g or more. Further, in JP-A-55-162418,
Alkaline aluminate aqueous solution and alkaline silicate aqueous solution
Disclosed is a method for producing an amorphous aluminosilicate which is continuously supplied to a reaction system at a temperature of 60 ° C. or lower, has a large particle size, is easy to filter and wash, and has excellent ion exchange ability.
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 an alkali metal aluminate solution and an alkali metal silicate solution are added to water at a temperature of 60 ° C. or lower, or an alkali metal silicate solution is added. A method for producing an amorphous aluminosilicate that has an oil absorption of 200 ml / 100 g or more and a cation exchange capacity that is equivalent to physical properties of various zeolites by adding it to an alkali metal aluminate salt solution at a temperature of 60 ° C or less. Is disclosed. However, in this method, all steps of the reaction are carried out at 60 ° C. or lower, and Na ₂ O in the alkali metal aluminate salt solution used is also used.
And Al ₂ for the molar ratio Na ₂ O / Al ₂ O ₃ of O ₃ is 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 is characterized in that an alkali metal silicate aqueous solution is added to an alkali metal aluminate aqueous solution under strong stirring at a temperature of 15 to 60 ° C., and then heat treated at a temperature of 70 to 100 ° C. The present invention provides a method for producing an amorphous aluminosilicate, and in a further preferred embodiment, an aqueous solution of alkali metal aluminate is Na ₂ O and Al ₂ O _3.
Alkali metal salt of low alkali aluminate having a molar ratio of Na ₂ O / Al ₂ O ₃ = 1.1 to 1.7 and a molar ratio of H ₂ O and Na ₂ O of H ₂ O / Na ₂ O = 6.5 to 500 It is an aqueous solution, the aqueous solution of alkali metal silicate is SiO ₂ and Na ₂ O = 1.0-4.0, and the molar ratio of H ₂ O and Na ₂ O is H ₂ O / Na ₂ O = 12-200. The present invention provides a method for producing the above-mentioned amorphous aluminosilicate which is an aqueous solution of an acid alkali metal salt.

The raw materials for producing the highly oil-absorbing and highly ion-exchangeable amorphous aluminosilicate of the present invention are (a) an alkali metal aluminate salt solution and (b) an alkali metal silicate solution, and caustic if necessary. 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 Ia 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 Aqueous Solution Aqueous alkali metal aluminate solution may be a commercially available product, 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 necessary amount of water and alkali hydroxide may be used. The adjustment of the high-concentration solution at this time is stabilized by heating and dissolving the aluminum source with alkali hydroxide and then rapidly cooling, but it is desirable to adjust the necessary amount for lower alkali solutions each time. Regarding the aqueous solution of alkali metal aluminate 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 0.9 to 10%, 1.0 to
A range of 5.8% is particularly preferred. 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, the above-mentioned (a) alkali metal aluminate salt aqueous solution is put into a reaction tank, the temperature is kept at 15 to 60 ° C., and the above-mentioned (b) alkali metal silicate salt aqueous solution is added under vigorous stirring. The white precipitate slurry formed was then added to 70-100
℃, preferably heated to a temperature of 90 ~ 100 ℃, 10 minutes or more,
Preferably, the temperature is kept for 30 minutes or more to obtain an amorphous aluminosilicate having a strong higher order structure. 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. But,
If the initial temperature is too high, the oil absorption capacity of the obtained amorphous aluminosilicate will be 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. Also
No strong stirring is required for the heat treatment at 70 to 100 ° C. This heat treatment is preferably performed while keeping the reaction system as it is, but may be performed after partially concentrating by filtration or decantation.

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 with this molar ratio is obtained in a high yield, a product with the physical properties aimed at by the present invention can be obtained in a high yield.

In the case of a mixing method of both liquids other than the method of the present invention,
It should be added that the yield may be maximum when Si / Al = 2 (molar ratio).

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 subjected to filtration, washing and drying without heat treatment by the method described in JP-A-55-162418, the oil absorption becomes extremely poor, and 200 ml / 10
It is difficult to obtain values above 0g. It is possible to obtain an oil absorption amount of 200 ml / 100 g or more under the condition of a large amount of alkali content of the reaction system, but it is still possible to obtain an oil absorption capacity of 250 ml / 100 g or more, except for the method of the present invention. Have difficulty.

[Work]

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 diameter becomes smaller as the concentration becomes lower and the addition speed becomes faster, and the particle diameter 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. Furthermore, under reaction conditions of 60 ° C. or less, a large number of hydroxyl groups on the surface of particles are present, 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. in this way,
It is considered that when the production method of the present invention is adopted, the aggregated particle structure at the time of heat strengthening becomes the largest and strong.

〔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 JIS K 6220 oil absorption measurement method.

(2) Ignition Loss Bake in advance at 800 ° C for 1 hour, put a few grams of sample into the magnetic crucible that has reached a constant weight in a desiccator, and weigh accurately.
Then, the material was ignited in an electric furnace at 800 ° C. for 1 hour, and the weight that reached a constant weight was precisely weighed in a desiccator to determine the ignition loss in% by weight.

(3) Ca ion exchange capacity A sample of 0.1 g was accurately weighed in terms of anhydride calculated from loss on ignition, added to 100 ml of calcium chloride solution (500 ppm as CaCO ₃ ) and stirred at 25 ° C for 15 minutes, Suction filtration is performed by stacking two sheets of Toyo Filter Paper No. 5c, and 50 ml of the filtrate is taken to remove Ca in the filtrate.
EDTA 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 p1200 (trade name) of Rigaku Denki Co., Ltd.
It was measured using α rays.

Implementation examples 1 to 5 were after mixing heated and dissolved aluminum hydroxide and sodium hydroxide, Na ₂ O20.3 wt% by performing the subsequent rapid cooling, Al ₂ O
_A sodium aluminate solution containing 38.2% by weight and Al ₂ O ₃ / Na ₂ O = 0.847 (molar ratio) is prepared in advance. 17.44 g of this solution
To the above, a predetermined amount of water was added with stirring as shown in Table 1, and the mixture was maintained at 30 ° C. Then, while stirring with a magnetic stirrer piece having a diameter of 48 mm at a rotation speed of 1500 rpm, sodium silicate solution (Na ₂ O 3.8 wt%, SiO ₂ 11.6
50% by weight, SiO ₂ / Na ₂ O = 3.15 (molar ratio)) was added.
After the addition was completed, reduce the rotation speed of the stirrer to 500 rpm and immediately
Heating was carried out at 100 ° C. for 1 hour, followed by filtration and washing.
The obtained wet cake was allowed to stand and dry at 110 ° C. until a constant weight was obtained, and then pulverized to obtain an amorphous aluminosilicate of the present invention. The results of measuring the physical properties of this product are shown in Table 1.

Example 6 50 g of a sodium silicate solution (Na ₂ O 3.8% by weight, SiO ₂ 11.6% by weight, SiO ₂ / Na ₂ O = 3.15 (molar ratio)) was added to a sodium aluminate solution (Na ₂ O 1.12% by weight). , Al ₂ O ₃ 1.55% by weight, Na ₂ O /
Al ₂ O ₃ (1.18 (molar ratio)) 317.4 g was added with a microtube pump at 40 ° C. under strong stirring. Immediately after completion of the addition, heating was performed at 100 ° C. for 1 hour, and then filtration and washing were performed. The obtained wet cake was dried at 110 ° C. to a constant weight and pulverized to obtain 12.8 g of X-ray amorphous aluminosilicate fine powder. Yield 93
%Met. This powder had physical properties such as an oil absorption of 310 ml / 100 g and an ion exchange capacity of 112 CaCO ₃ mg / 1 g.

Implementation example 7 sodium silicate solution (Na ₂ O3.9 wt%, SiO ₂ 12.0 _{wt%, SiO 2 / Na 2 O} = 3.15 ( molar ratio)) 48.3 g of sodium aluminate solution (Na ₂ O1.94 weight %, Al ₂ O ₃ 1.89% by weight, Na ₂
O / Al ₂ O ₃ = 1.59 (molar ratio)) 338.3 g, and added at 40 ° C. under strong stirring. Immediately after completion of the addition, heating was performed at 100 ° C. for 1 hour, and then filtration and washing were performed. Thereafter, the same operation as in Example 6 was carried out to obtain an X-ray amorphous aluminosilicate fine powder. The oil absorption capacity of this product was 265 ml / 100 g, and the ion exchange capacity was 138CaCO ₃ mg / 1 g.

Example 8 A sodium aluminate solution (Na ₂ O
1.63% by weight, Al ₂ O ₃ 2.26% by weight, 2392 g of Na ₂ O / Al ₂ O ₃ = 1.18 (molar ratio)) were charged and kept at 30 ° C. Sodium silicate solution (Na ₂ O 3.8% by weight, SiO ₂ 11.6% by weight, S
550 g of iO ₂ / Na ₂ O = 3.15 (molar ratio) was added while rotating a stirring blade having a diameter of about 110 mm at 650 rpm. Immediately after the addition was completed, the mixture was heated to 100 ° C. and held for 1 hour, and then the same operation as in Example 6 was carried out to obtain 142 g of X-ray amorphous aluminosilicate fine powder. The yield was 94%. This product has an oil absorption capacity of 298 ml / 100g and an ion exchange capacity of 127 CaCO _3.
It was mg / 1g.

Example 9 A sodium aluminate solution (Na ₂ O
1.12 wt%, Al ₂ O ₃ 1.55 wt%, Na ₂ O / Al ₂ O ₃ = 1.18 (molar ratio)) 3492 g were charged, and a sodium silicate solution (Na ₂ O 3.8 wt%, at a reaction temperature of 28 ° C., SiO ₂ 11.6% by weight, SiO ₂ / Na
₂ O = 3.15 (molar ratio)) 550 g with a stirring blade of about 110 mm in diameter
Added while rotating at 80 rpm. Immediately after addition is complete 1
After heating to 00 ° C. and holding for 1 hour, the same operation as in Example 6 was performed to obtain 141 g of an X-ray amorphous aluminosilicate fine powder. The oil absorption capacity of this product was 315 ml / 100 g, and the ion exchange capacity was 131 CaCO ₃ mg / 1 g.

Comparative Example 1 In the same operation as in Example 6, an amorphous aluminosilicate was obtained without heat treatment at 100 ° C. for 1 hour. The oil absorption of this product was 70 ml / 100 g.

Comparative Example 2 In the same operation as in Example 7, the heat treatment at 100 ° C. for 1 hour was not performed, and the operation was performed at 40 ° C. for 30 minutes to obtain an amorphous aluminosilicate. The oil absorption capacity of this product was 223 ml / 100 g, and the ion exchange capacity was 82 CaCO ₃ mg / 1 g.

Comparative Example 3 In the same operation as in Example 8, amorphous aluminosilicate was obtained without heat treatment at 100 ° C. for 1 hour.
The oil absorption capacity of this product is 198 ml / 100g, and the ion exchange capacity is 78CaCO.
It was ₃ mg / 1 g.

〔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. A method of adding an alkali metal silicate aqueous solution to an alkali metal aluminate aqueous solution under strong stirring at a temperature of 15 to 60 ° C., and then performing heat treatment at a temperature of 70 to 100 ° C. And a method for producing amorphous aluminosilicate. 2. An aqueous solution of an alkali metal aluminate is Na ₂ O.
Molar ratio of Al ₂ O ₃ is _{Na 2 O / Al 2 O 3} = 1.1~1.7, and between H ₂ O
A low-alkali alkali metal aluminate alkali metal salt aqueous solution in which the molar ratio of Na ₂ O is H ₂ O / Na ₂ O = 6.5 to 500, and the aqueous solution of alkali metal silicate has a molar ratio of SiO ₂ and Na ₂ O of SiO _{2. 2} / Na ₂ O = 1.0
˜4.0, and the molar ratio of H ₂ O and Na ₂ O is H ₂ O / Na ₂ O = 12 to 200
The method for producing an amorphous aluminosilicate according to claim 1, which is an aqueous solution of an alkali metal silicate.