JP2013040066A - Method for manufacturing lamellar silicate compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a lamellar silicate compound, which provide a large crystal.SOLUTION: The method for manufacturing a lamellar silicate compound includes a hydrothermal treatment step of reacting a mixed aqueous solution containing SiOand NaO under a hydrothermal condition. Before the hydrothermal treatment step is carried out, a charging step of filling the mixed aqueous solution and a ball for a medium in a vessel is carried out; and in the hydrothermal step, the vessel filled with the mixed aqueous solution and the ball for a medium is placed for a first predetermined time under a hydrothermal condition, and thereafter, the ball for a medium is removed and the mixed aqueous solution is placed for a second predetermined time under a hydrothermal condition.

Description

  The present invention relates to a method for producing a layered silicate compound used for, for example, a catalyst, an adsorbent, an ion exchanger, an extender pigment, a base material of a composite material, and more specifically, a layered silicate compound crystal It is related with the manufacturing method of the layered silicate compound from which the big crystal | crystallization is obtained after achieving shortening of the synthesis time of.

  Layered silicate minerals such as magadiite, kanemite, macaite, iraite, kenyaite, and the like can be expanded and contracted between layers. It is used as a carrier for sorption materials, ion exchangers, softeners, catalysts and the like. In addition, layered silicate minerals can control the selectivity to adsorbed substances and improve heat resistance by changing the layer structure by intercalation with oxides such as silica and modification of silanol groups on the surface of the layer. In other words, it has been used as an adsorbent material, a separation material such as a column material, a water repellent material, an oil repellent material, a catalyst carrier for purifying exhaust gas, a filler, and the like.

Among these layered silicate minerals, Irayaite (chemical formula Na ₂ O · 8SiO ₂ · 10H ₂ O) has a layered structure of planar silicic acid skeleton, and has silanol groups between layers, magadiite and Kenyaite. It has characteristic properties not found in other layered silicate minerals. For example, the shape of the particles of Iraite is a very regular rectangular plate and has a very high dispersibility. Therefore, as a host compound in various functional materials, an ultraviolet shielding material (for example, an inorganic nanoparticle coating treatment) , Patent document 1), pearl pigment (for example, refer to patent document 2), mesopore porous material by intercalation (for example, refer to patent document 3), catalyst (for example, refer to non-patent document 1), organic / inorganic hybrid material (See, for example, Non-Patent Document 2).

Since Iraite does not exist in nature, it can only be obtained by artificial synthesis. For the synthesis of islayite, a mixed aqueous solution in which colloidal silica and sodium hydroxide are mixed (for example, a composition of 0.25 mol of Na ₂ O and 7.5 mol of water per mol of SiO ₂ ) is made of stainless steel (SUS304). A synthesis method in which the reaction is carried out under a hydrothermal condition of about 100 ° C. by filling the container in an oven and placing it in an oven is widely adopted (see, for example, Patent Document 4).

Japanese Patent No. 38765521 JP 2006-124524 A Japanese Patent No. 2949215 JP-A-9-227116

"Synthesis and characterization of transition metal oxide-pillared materials with mesoporosity from layered silicate ilerite" Sun Jin Kim, Eun Ji Kim, Tae Bum Kang, Kwang-Doeg Jung, Oh-Shim Joo, Chae-Ho Shin, Journal of Porous Materials 13 (2006) 27-35 "Synthesis of new microporous layered organic-inorganic hybrid nanocomposites by alkoxysilylation of a crystalline layered silicate, ilerite" Ryo Ishii, Takuji Ikeda, Tetsuji Itoh, Takeo Ebina, Toshirou Yokoyama, Takaaki Hanaoka, Fujio Mizukami, Journal of Materials Chemistry 16 (2006) 4035-4043

  By the way, in the synthesis method as described above, by placing the mixed aqueous solution under hydrothermal conditions, sodium silicate molecules having a relatively large molecular weight are reduced in molecular weight by hydrolysis, and further between the sodium silicate molecules that have been reduced in molecular weight. When the condensation polymerization occurs, a precursor of the crystal nucleus of Iraite called a secondary structure unit of a silica skeleton is generated. As the polycondensation proceeds further between these precursors, Iraite crystal nuclei are formed, and the crystal nuclei grow to produce Ilayite crystals.

  However, although crystal growth proceeds rapidly after the formation of crystal nuclei, the induction period until the formation of crystal nuclei is very long, requiring one week or more. For example, when hydrothermal treatment is performed at 100 ° C. The induction period is about 18 days. Although the induction period can be shortened slightly by increasing the heating temperature in hydrothermal treatment, other layered silicate compounds (magadiaite) begin to form as the temperature rises. Such shortening is difficult. For this reason, since the induction period is very long, energy consumption such as electric power increases, and as a result, the manufacturing cost increases, and at present, Ilayite has not yet achieved industrial application development.

In order to solve this problem, the present applicant has previously proposed a method for producing a layered silicate compound in which a mixed aqueous solution and a ceramic (metal oxide) medium ball are filled in a container and a hydrothermal treatment step is performed. I applied for an idea. This promotes the generation of heterogeneous nuclei on the ball surface of the crystal nuclei of Iraite, thereby facilitating the formation of the precursors of the crystal nuclei and the rapid formation of crystal nuclei by hydrothermal treatment of the precursors. The synthesis time was shortened.
Furthermore, the present applicant studied a method for producing a layered silicate compound in which a mixed aqueous solution and a ceramic medium ball are filled in a container and a hydrothermal treatment step is performed. As a result, in the hydrothermal treatment step, the container filled with the mixed aqueous solution and the medium ball is placed under a hydrothermal condition for a predetermined time (for example, one day), and then the medium ball is removed to remove only the mixed aqueous solution. It was found that large crystals (for example, 3 μm or more) can be obtained by placing them under thermal conditions for a predetermined time (for example, one week).

That is, the method for producing a layered silicate compound of the present invention is a method for producing a layered silicate compound including a hydrothermal treatment step in which a mixed aqueous solution containing SiO ₂ and Na ₂ O is reacted under hydrothermal conditions. Before performing the hydrothermal treatment step, the charging step of filling the mixed aqueous solution and the medium ball into a container is performed. In the hydrothermal treatment step, the mixed aqueous solution and the medium ball are After the filled container is placed under hydrothermal conditions for a first predetermined time, the medium ball is removed and the mixed aqueous solution is placed under hydrothermal conditions for a second predetermined time.

  Here, the “first predetermined time” and the “second predetermined time” are arbitrary times determined in advance by an experimenter or the like.

  According to the method for producing a layered silicate compound of the present invention, the synthesis time of the layered silicate compound crystal can be shortened and a large crystal can be obtained.

(Means and effects for solving other problems)
Further, in the method for producing a layered silicate compound of the present invention, the container is a ball mill, and before the hydrothermal treatment step is performed, a milling process step of milling the mixed aqueous solution using the ball mill is performed. You may do it.
According to the method for producing a layered silicate compound of the present invention, the synthesis time of the layered silicate compound crystal can be further shortened, and the ball mill used in the milling treatment step can be used as it is in the hydrothermal treatment step. .

Moreover, in the manufacturing method of the layered silicate compound of this invention, you may make it said 1st predetermined time be 12 hours or more and 36 hours or less.
In the method for producing a layered silicate compound of the present invention, the medium ball may be a zirconia ball.
In the method for producing a layered silicate compound of the present invention, the diameter of the medium ball may be 1 mm or more and 5 mm or less.

And the manufacturing method of the layered silicate compound of the present invention is such that the mixed aqueous solution contains 23 wt% or more and 26 wt% or less of SiO ₂ and 6 wt% or more and 8 wt% or less of Na ₂ O. It may be.
Furthermore, in the method for producing a layered silicate compound of the present invention, the layered silicate compound may be Iraite, and the hydrothermal condition may be 90 ° C. or higher and 130 ° C. or lower.

The graph which shows the relationship between the hydrothermal treatment time put in 110 degreeC oven, and a yield. The graph which shows the relationship between the hydrothermal treatment time put in 110 degreeC oven, and a yield. The graph which shows the relationship between the magnitude | size of a layered silicate compound crystal | crystallization, and hydrothermal treatment time.

  Hereinafter, embodiments of the present invention will be described. Note that the present invention is not limited to the embodiments described below, and it goes without saying that various aspects are included without departing from the spirit of the present invention.

  The method for producing a layered silicate compound according to the present invention includes a mixed aqueous solution preparation step (A) for preparing a mixed aqueous solution, a preparation step (B) for filling the mixed aqueous solution and a medium ball into a container, and a mixed aqueous solution. The first hydrothermal treatment step (C) in which the medium balls are reacted under hydrothermal conditions, and the second hydrothermal treatment step (D) in which only the mixed aqueous solution is reacted under hydrothermal conditions.

(A) to prepare a mixed aqueous solution containing a mixed aqueous solution preparation step SiO ₂ and Na ₂ O.
As the SiO _2, it is preferable to use amorphous silica. In general, silica synthesized by a wet method may be used, and its history is not particularly limited. For example, silica obtained using sodium silicate or alkoxide as a raw material, or amorphous silica obtained by treating a silicate ore with a mineral acid can be used.
As the Na 2 _O, using sodium hydroxide is preferred.
Water glass (sodium silicate, (No. 4 water glass)) can be used as it is, or it can be used by adjusting the concentration by adding a silica source, a sodium source or water to the water glass.
The mixed aqueous solution preferably contains 23 wt% or more and 26 wt% or less of SiO ₂ and 6 wt% or more and 8 wt% or less of Na ₂ O.

(B) Preparation process The mixed aqueous solution and medium balls are filled in a container.
In order to prevent contamination of the product, it is preferable to use a container made of ceramic or a metal whose inner surface is coated with a wear resistant material such as a fluororesin.
The medium balls are preferably made of zirconia, stainless steel, nylon, alumina, silicon carbide, more preferably made of ceramic, and more preferably made of zirconia in order to prevent product contamination and promote crystal nucleation. Is particularly preferred. The diameter of the medium ball is preferably from 0.1 mm to 10 mm, more preferably from 1 mm to 5 mm, and particularly preferably from 1 mm to 3 mm.

(C) First hydrothermal treatment step Both the medium ball and the mixed aqueous solution are placed in an oven to react under hydrothermal conditions of 90 ° C or higher and 130 ° C or lower. The time to put in the oven may be 6 hours or more, but is preferably 12 hours or more and 36 hours or less.

(D) Second hydrothermal treatment step After the mixed aqueous solution is taken out from the previous container, only the mixed aqueous solution is filled in a new container and placed in an oven, under hydrothermal conditions of 90 ° C or higher and 130 ° C or lower. React. The time for placing in the oven may be 12 hours or longer, but is preferably 24 hours or longer.
The new container is preferably made of ceramic or a metal whose inner surface is coated with a wear resistant material such as fluororesin in order to prevent contamination of the product.

  In addition, you may perform a milling process process between the (B) preparation process and the (C) 1st hydrothermal process. At this time, the rotational speed of the ball mill is preferably 20% to 150%, more preferably 80% to 120% of the theoretical critical rotational speed. Moreover, it is preferable that the temperature at the time of a milling process is 0 to 40 degreeC, and it is more preferable that it is 20 to 30 degreeC. Furthermore, the milling treatment time is preferably 2 hours to 12 hours, more preferably 3 hours to 6 hours from the viewpoint of yield.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

<Example 1> Manufacture of Iraite according to Example 1 (A) Mixed aqueous solution preparation step No. 4 water glass (manufactured by Kanto Chemical Co., Inc., SiO ₂ : 24.3% by weight, Na ₂ O: 6.7% by weight) Prepared.
(B) Preparation process A sealed container made of stainless steel (SUS304) having a capacity of 200 ml was charged with 39 g (about 30 ml) of No. 4 water glass and 235 g of zirconia balls having a diameter of 3 mm.

(C) First hydrothermal treatment step Hydrothermal treatment was performed by placing the sealed container in an oven at 110 ° C for 24 hours.
(D) Second hydrothermal treatment step After the mixed aqueous solution is taken out from the sealed container, only the mixed aqueous solution is filled in a sealed container made of stainless steel (SUS304) and placed in an oven at 110 ° C. for 5 days for water. Heat treated. And the synthetic | combination was taken out and wash | cleaned, and the eyelashite which concerns on Example 1 was produced by drying in the air of 40 degreeC for 3 days.

<Comparative example 1> Manufacture of Iraite according to Comparative Example 1 Example 1 except that the second hydrothermal treatment step in Example 1 was not performed and the first hydrothermal treatment step was put in an oven at 110 ° C for 8 days. In the same manner as above, an eyelashite according to Comparative Example 1 was produced.
<Comparative example 2> Manufacture of an eyelash according to comparative example 2 An eyelash according to comparative example 2 was produced in the same manner as in comparative example 1 except that the zirconia balls were not filled in the preparation step in comparative example 1.

<Evaluation 1> Yield Yields of the eyeraite according to Example 1 and the eyeraite according to Comparative Examples 1 and 2 were calculated. At this time, as the yield of Iraite, the ratio (% by weight) of the generated solid phase weight to the maximum amount of Iraite that can be synthesized stoichiometrically from the water glass charged in the sealed container was calculated. The results are shown in FIGS. 1 and 2 are graphs showing the relationship between the hydrothermal treatment time in a 110 ° C. oven and the yield.

As shown in FIG. 1, in the method for producing Iraite according to Comparative Example 1, crystal growth became remarkable after an induction period of about 2 days, and the yield reached equilibrium after 7 days. On the other hand, in the method for producing Iraite according to Comparative Example 2, crystal growth became remarkable after an induction period of about 7 days, and the yield reached equilibrium after 11 days.
In addition, as shown in FIG. 2, there is no significant difference in crystal growth between the method for producing Iraite according to Example 1 and the method for producing Iraite according to Comparative Example 1, and it can be placed in an oven for 2 days in the hydrothermal treatment process. As a result, Iraite could be obtained.
As described above, it was confirmed that in the method for producing Iraite according to Example 1, it was possible to synthesize Iraite in less than half the time compared with the method for producing Iraite according to Comparative Example 2.

<Evaluation 2> Particle Diameter The particle diameters of the eyelets according to Example 1 and Comparative Example 1 were measured with a laser diffraction / scattering particle size distribution measuring apparatus. The result is shown in FIG. FIG. 3 is a graph showing the relationship between the size (median diameter) of the layered silicate compound crystal and the hydrothermal treatment time. The median diameter is the particle diameter when the proportion of particles larger than a certain particle diameter in the particle size distribution occupies 50% of the whole.
As shown in FIG. 3, it was found that in the method for producing Iraite according to Comparative Example 1, the median diameter hardly changed even when the hydrothermal treatment time was increased. On the other hand, in the method for producing Iraite according to Example 1, it was found that the median diameter becomes larger as the hydrothermal treatment time becomes longer.
As described above, it can be confirmed that the method for producing eyeraite according to Example 1 can synthesize large amount of eyeraite compared with the method for producing eyeraite according to Comparative Example 1.

  The present invention can be used for, for example, a method for producing a layered silicate compound used for a catalyst, an adsorbent, an ion exchanger, an extender pigment, a base material of a composite material, and the like.

Claims (7)

A method for producing a layered silicate compound comprising a hydrothermal treatment step in which a mixed aqueous solution containing SiO ₂ and Na ₂ O is reacted under hydrothermal conditions,
Before performing the hydrothermal treatment step, execute a charging step of filling the container with the mixed aqueous solution and the medium ball,
In the hydrothermal treatment step, after the container filled with the mixed aqueous solution and the medium ball is placed under hydrothermal conditions for a first predetermined time, the medium ball is removed and the mixed aqueous solution is placed under hydrothermal condition. A method for producing a layered silicate compound, characterized by being placed for a second predetermined time. The container is a ball mill;
2. The method for producing a layered silicate compound according to claim 1, wherein a milling process step of milling a mixed aqueous solution using the ball mill is performed before the hydrothermal process is performed.   The method for producing a layered silicate compound according to claim 1 or 2, wherein the first predetermined time is 12 hours or more and 36 hours or less.   The method for producing a layered silicate compound according to any one of claims 1 to 3, wherein the medium ball is a zirconia ball.   The diameter of the said ball | bowl for media is 1 mm or more and 5 mm or less, The manufacturing method of the layered silicate compound in any one of Claims 1-3 characterized by the above-mentioned. 6. The mixed aqueous solution contains 23% by weight or more and 26% by weight or less of SiO ₂ and 6% by weight or more and 8% by weight or less of Na ₂ O. The manufacturing method of the layered silicate compound of description. The layered silicate compound is Iraite
The method for producing a layered silicate compound according to claim 6, wherein the hydrothermal condition is 90 ° C or higher and 130 ° C or lower.

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