JP3505730B2 - Amorphous aluminosilicate and its use - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous aluminosilicate.
The present invention relates to a free polyvalent metal ion remover in an aqueous solution consisting of a novel amorphous aluminosilicate having an improved microporous structure.
It relates to a valent metal ion remover . 2. Description of the Related Art Amorphous aluminosilicates are generally prepared by mixing an aqueous solution of sodium aluminate and an aqueous solution of sodium silicate at an appropriate temperature, concentration and concentration ratio, for example, 6%.
It was thought that it could be easily obtained only by mixing at a temperature of about 0 ° C. and, if necessary, additional sodium hydroxide aqueous solution. The aluminosilicate synthesized in this way was fine and was considered to be convenient for use as any industrial raw material because of its moderate oil absorption and ion exchange properties. To give a specific example, for example, Japanese Patent Application Laid-Open No. 49-64600 discloses a method for synthesizing amorphous aluminosilicate, which is used as a raw material for synthesizing zeolite and is obtained. No mention is made of the physical properties such as the pore structure of amorphous aluminosilicate. Further, Japanese Patent Application Laid-Open
Japanese Patent Application Publication No. 156527 specifies that the concentration of the alkali metal oxide is not more than a certain concentration. However, no attention is paid here to the pore structure, and it is considered that fine pores essential for the present invention have not been developed. [0003] When an amorphous aluminosilicate prepared by a conventional method is used, for example, as a catalyst, it must be uniformly modified as a catalyst (for example, a useful metal ion is not used). It is difficult to perform ion exchange and to carry them, and it is difficult to obtain uniform performance as a catalyst.
Further, when used as an ion exchanger, its ion exchange performance is not sufficient. Also, when impregnating with an oily substance, the absorption amount, absorption rate and absorption stability were insufficient. It is considered that these reasons are caused by the fact that the fine pore structure has not been developed. Further, it is considered that the amorphous aluminosilicate in which the fine pore structure has not been developed has large primary particles forming the same, and thus causes poor pulverizability of the particles. [0004] As described above, it has been a very important task to improve the pore structure of amorphous aluminosilicate and to improve the pulverizability, furthermore the ion exchange performance and the absorbability of oily substances. The inventors of the present invention have conducted intensive studies on the physical properties and properties of amorphous aluminosilicate, and as a result, by improving the pore structure of the amorphous aluminosilicate, the pulverizability and the like have been improved. Further, the ion exchange property and the oil absorbability can be improved, and a close relationship between the pore structure and these properties has been found, leading to the present invention. That is, the present invention provides 1 00 Angstrom pore volume of less diameter 0.05 cm ³ / g or more, a specific surface area determined by BET method 100 m ²
/ G or more, the molar ratio of SiO ₂ / Al ₂ O ₃ is 1.8.
The free polyvalent metal ion removing agents amorphous aluminosilicate or Ranaru aqueous solution of 5.0 it is an gist.
By forming a fine pore structure of 100 Å or less as a volume of 0.05 cm ³ / g or more,
The ion exchange rate increases, and the absorbability of oily substances increases. Further, if the porous structure having a specific surface area of 100 m ² / g or more is provided in addition to the condition of the pore volume, the diffusion of the substance into the powder becomes easy, and the ion exchange property and the absorption of the oily substance are further improved. Etc. improve. Therefore, they have extremely high performance as agents for removing free metal ions in aqueous solutions. Next, the gist of the present invention will be described in more detail.
In the present invention, in a general method of producing an amorphous aluminosilicate by reacting an aqueous solution of an alkali metal aluminate and an aqueous solution of an alkali metal silicate, by optimizing the temperature, concentration ratio, solution addition method and the like. It was revealed that the pore structure of the obtained amorphous aluminosilicate changed greatly. Here, the improved pore structure refers to, for example, a pore structure of a powder obtained by spray-drying the obtained amorphous aluminosilicate, and
It has a pore structure developed below angstrom. Observation of the pore distribution of these by the mercury intrusion method usually reveals pores of about 100 to 2,000,000 angstroms, and 100,000 to 100,000 angstroms.
From Å to 2,000,000 Å, the presence of intergranular pores is confirmed. In the measurement of the specific surface area by the BET method, the pores of 5 angstrom or more are in the measurement range, so that the difference from the specific surface area measured by the mercury intrusion method indicates that there are pores of 100 angstrom or less. When the fine pore structure is developed, the difference in specific surface area represented by the following formula, (specific surface area by BET method)-(specific surface area by mercury intrusion method) becomes large. According to the invention, this difference is preferably greater than or equal to 8 m ² / g. In addition, in the present invention, 100
The volume of pores less than Angstroms is calculated by the following method. That is, the difference in the specific surface area is 1
The specific surface area of pores of not more than 00 Å. Therefore, assuming that the average pore diameter is 50 angstroms, a pore volume of 100 angstroms or less is virtually calculated from the specific surface area by the following equation. Pore volume = difference in specific surface area ÷ (50 × π) ×
(25 × 25 × π) ÷ 10000 For example, if the difference in the specific surface area is 8 m ² / g, the difference is 0.1.
Calculated as 01 cm ³ / g. On the other hand, an amorphous aluminosilicate whose pore structure is not improved does not develop a pore structure of 100 Å or less. As a result, when the pore distribution was observed by the mercury intrusion method, it was found that the pore size ranged from 100,000 angstroms to 1,000,000 angstroms.
At the same time as the presence of intergranular pores is confirmed, intragranular pores can be confirmed from 100 angstroms to 10,000 angstroms. Also, in comparison with the specific surface area by the BET method, since there are almost no pores at 100 Å or less, the difference in the specific surface area is almost zero,
Or it becomes 0 or less. The reason why the specific surface area is 0 or less is that when the specific surface area is calculated by the mercury intrusion method, the specific surface area is excessively evaluated if there are many ink bottle type pores, that is, a large number of pores having a narrow entrance and a wide inside. It is known and it is considered as a cause. As described above, the amorphous aluminosilicate having an improved pore structure and having pores of 100 angstrom or less has excellent pulverization characteristics, high ion exchange property and oil absorption property. The amorphous aluminosilicate obtained by the present invention has a general formula of 0.8 to 1.2 M ₂ O.Al ₂ O ₃ .1.8 to 5.0 Si without containing bound water.
O ₂ (where M represents an alkali metal ion). Hereinafter, a method for producing the amorphous aluminosilicate of the present invention will be described. In the present invention, for example, an aqueous solution of an alkali metal aluminate and an aqueous solution of an alkali metal silicate are used as raw materials. If necessary, the two solutions are diluted with an aqueous solution of an alkali hydroxide and used. The aqueous solution may be a commercially available aqueous solution of an alkali metal aluminate or an aqueous solution of an alkali metal silicate, or an aqueous solution of an alkali such as aluminum hydroxide or a silica source such as silicic acid. Heat treatment or the like may be performed together with the aqueous alkali metal salt solution to prepare both solutions. The alkali used is usually sodium, but is not particularly limited to sodium. The concentration of the aqueous solution of the alkali metal aluminate (eg, sodium aluminate, potassium aluminate, etc.) is not particularly limited, but is generally 30% in terms of Al ₂ O _3.
Used in wt% concentration, and the concentration in particular restrictions of the alkali metal salt solution silicate (e.g. sodium potassium silicate and silicic acid, etc.) although not generally 30% by weight or less of SiO ₂ display. Both of these aqueous solutions are supplied to the reaction system. The addition ratio of the aqueous alkali metal aluminate solution and the aqueous alkali metal silicate solution is not particularly limited. However, in an amorphous aluminosilicate having an extremely high SiO ₂ / Al ₂ O ₃ content, If the ion exchange property is impaired, and if the ion exchange property is extremely low, the absorbability of the oily substance is reduced, the SiO ₂ / A
in terms of the molar ratio of l ₂ O ₃ 0.5 to 10 preferably 1.
Supplied to be 5-5. However, these ratios are not particularly limited in the present invention. A particularly important point in the mixing of these raw materials is that water and an aluminum raw material are first charged into a reaction vessel, the aluminum concentration is reduced as much as possible, and a silica raw material is added thereto. It is also important that the mixing is sufficiently stirred so that the generated gel does not partially stay. The reaction is usually carried out at a temperature not higher than the boiling point of the solution. However, when the temperature exceeds 60 ° C., it is often difficult to form a fine pore structure of 100 Å or less.
It is desirable to carry out at 0 ° C. or less, preferably at 35 ° C. or less.
Particularly, the synthesis at a temperature of 30 ° or less is effective in forming a fine pore structure and increasing the specific surface area. It is also a fact that when the reaction is carried out at a high temperature, part of the amorphous aluminosilicate is crystallized into zeolite or the like, and the absorbability of the oily substance is significantly reduced. The reaction time is preferably 10 minutes to 5 hours.
If the reaction time is set too long, crystallization proceeds even when the synthesis is performed at a low temperature, and the above-described inconvenience occurs. In addition, the excess alkali content is reduced as much as possible by using carbon dioxide gas or sodium hydrogen carbonate during mixing and synthesis of the raw materials, so that the growth of the fine pore structure can be achieved as in the case of synthesis at a low temperature. It is effective in increasing the specific surface area. Therefore, low temperature (30 ° C or less)
Then, when the synthesis is performed while neutralizing the excess alkali, a pore having a specific surface area of 100 m ² / g or more and a pore volume of 100 Å or less and 0.05 cm ³ / g or more can be easily obtained. The thus obtained slurry is subjected to solid-liquid separation, if necessary, and spray-dried to obtain an amorphous aluminosilicate having an improved pore structure. EFFECT OF THE INVENTION The release of an amorphous aluminosilicate obtained by the present invention in an aqueous solution comprising an amorphous aluminosilicate having an improved pore structure.
The metal ion remover has small primary particles and is excellent in pulverizability. In addition, the ion exchange property and the oil absorbability have also been improved. Next, the present invention will be described in more detail with reference to Examples. The respective measuring methods in Examples and Comparative Examples are as follows. (1) Method of Measuring Pore Distribution and Specific Surface Area by Mercury Intrusion Method The measurement was carried out using a pore sizer 9310 manufactured by Micromeritics. (2) Measurement method of specific surface area by BET method Measurement was performed using Flowsorb II2300 manufactured by Micromeritics Co., Ltd. (3) Test method for crushability After crushing an amorphous aluminosilicate gel with a cooking cutter for 2 minutes, a microtrack MKIIISPA / -PC7997-30 manufactured by LEEDS & NORTHRUP is used.
Was used to measure the particle size distribution. (4) Method of Measuring Ion Exchange Capability Ion exchange capacity was measured by adding 1 liter of an aqueous calcium chloride solution (500 mg / liter in terms of calcium carbonate).
Add 1 g of amorphous aluminosilicate in terms of anhydrous
Stirred at 5 ° C. for 10 minutes. Then, after the solid content is separated by filtration, calcium remaining in the filtrate is removed by EDTA.
Measured by titration with an aqueous solution, CaCO ₃ calcium exchange capacity per amorphous aluminosilicate 1 g (anhydrous)
I converted it to (5) Method for measuring the absorbability of oily substances The linseed oil method was used according to JIS K 6221. Example 1 1169 g of water was charged into a reaction vessel having an inner volume of 5 liters, and while maintaining the temperature at 20 ° C., a sodium aluminate aqueous solution (Na ₂ O = 19.3% by weight, Al ₂ O _Three
= 21.9% by weight), while maintaining the temperature at 20 ° C, 323 g was added, and the mixture was stirred vigorously. Further, an aqueous solution of sodium silicate (Na ₂ O = 4.0% by weight, SiO ₂ = 1) was added to the solution.
2.7 wt%) was charged while maintaining the 1312 g to 20 ° C., were similarly vigorous stirring. Stirring was continued for 60 minutes from the end of the charging. Immediately thereafter, the obtained slurry was filtered, and the cake was further washed on a filter using ion-exchanged water twice the slurry volume. Since the obtained cake had a water content of about 75%, water was added so that the water content became 80%, and a slurry was formed into an amorphous aluminosilicate slurry having a slurry concentration of 20%. The obtained slurry was spray-dried at 100 to 150 ° C. as the product temperature, and the pore distribution, crushability, ion exchange performance, and oil absorption were measured by the above-described methods. Table 1 shows the results
It was shown to. Example 2 Water ( 1214 g) was charged into a 5 liter reaction vessel, and while maintaining the temperature at 30 ° C., a sodium aluminate aqueous solution (Na ₂ O = 19.3% by weight, Al ₂ O ₃
= 21.9% by weight), and 351 g was charged while maintaining the temperature at 30 ° C, followed by vigorous stirring. Further, an aqueous solution of sodium silicate (Na ₂ O = 4.0% by weight, SiO ₂ = 1) was added to the solution.
2.7 wt%) was charged while maintaining the 1240 g to 30 ° C., were similarly vigorous stirring. Stirring was continued for 60 minutes from the end of the charging. During addition and synthesis of each solution as raw material
Was bubbled at 300 cc / min. Immediately thereafter, the obtained slurry was filtered, and the cake was further washed on a filter using ion-exchanged water twice the slurry volume. The obtained cake was dried in the same manner as in Example 1.
After drying, the pore distribution, grindability , ion exchange performance and oil absorption were measured by the above methods. The results are shown in Table 1. COMPARATIVE EXAMPLE 1 During the addition and synthesis of each solution as a raw material, 300 carbon dioxide was added.
Same as Example 2 except that bubbling was not performed at cc / min.
The obtained cake was prepared in the same manner as in Example 1.
Dry, pore distribution, grindability, ion exchange performance and oil
The substance absorption was measured by the above method. The results are shown in Table 1.
Was. Comparative Example 2 Synthesis was performed in the same manner as in Example 1 except that the temperature was 30 ° C.
The obtained cake is dried in the same manner as in Example 1,
Pore distribution, grindability, ion exchange performance and oil absorption
Was measured by the above method. The results are shown in Table 1. Comparative Example 3 Water, 1038 g, was charged into a reaction vessel having an internal volume of 5 liters.
While keeping the temperature at 30 ° C,
Thorium aqueous solution (Na ₂ O = 19.3% by weight, Al ₂ O ₃
= 21.9% by weight) and kept at 30 ° C.
It was charged and stirred vigorously. In addition, sodium silicate
Lithium aqueous solution (Na ₂ O = 4.0% by weight, SiO ₂ = 1
(2.7% by weight) while charging 1517 g at 30 ° C
And stirred vigorously as well. 60 minutes from the end of loading
Stirring was continued for a while. Immediately thereafter, the obtained slurry is filtered.
And then add twice as much ion-exchanged water as the slurry volume.
Was used to wash the cake on the filter. The resulting cake
Is dried in the same manner as in Example 1, and the pore distribution, pulverizability,
Measurement of oil exchange performance and oil absorption
Was. The results are shown in Table 1. COMPARATIVE EXAMPLE 4 Water and 1,214 g were charged into a reaction vessel having an internal volume of 5 liters, and while maintaining a temperature of 65 ° C., an aqueous solution of sodium aluminate having the same composition as in Example 1 and silica The sodium aqueous solution was injected using a pump while simultaneously stirring 351 g and 1240 g of the sodium aqueous solution simultaneously. The time required for the introduction was about 7 minutes. Immediately thereafter, the obtained slurry was filtered to obtain an amorphous aluminosilicate.
Further, the cake was washed on a filter using ion-exchanged water twice the slurry volume, and the obtained gel was spray-dried in the same manner as in Example 1. Table 1 shows the evaluation results of the powder thus obtained. COMPARATIVE EXAMPLE 5 Water (1169 g) was charged into a reaction vessel having a capacity of 5 liters, and while maintaining the temperature at 65 ° C., an aqueous solution of sodium aluminate and an aqueous solution of sodium silicate having the same composition as Comparative Example 1 were placed in the vessel. Was added using a pump while simultaneously stirring 323 g and 1312 g of each at a time. The time required for the introduction was about 7 minutes. Stirring was continued for 50 minutes after the introduction. Immediately thereafter, the obtained slurry was filtered, and the same operation as in Example 1 was performed until spray-drying. Table 1 shows the evaluation results of the powder thus obtained. [Table 1] [0034]

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Claims (1)

(57) [Claims 1] SiO having a volume of pores having a diameter of 100 angstrom or less of 0.05 cm ³ / g or more and a specific surface area of 100 m ² / g or more determined by a BET method. ₂
Of free polyvalent metal ions in an aqueous solution of an amorphous aluminosilicate having a molar ratio of 1.8 to 5.0 / Al ₂ O ₃
Purgative .