JPS6241712A - Production of porous silica particle - Google Patents

Abstract

PURPOSE:To produce readily dispersible silica particles having uniform pores, by limiting the amount of an acid to be added in dissolving calcium in a calcium silicate compound with an acid. CONSTITUTION:Water is added to a calcium silicate compound to form a slurry, and hydrochloric acid or nitric acid at 1.0-1.3 neutralization equivalent ratio is dropped thereto and reacted therewith to selectively dissolve the calcium in the calcium silicate compound. The solid is then separated from the liquid, washed and dried. Thereby, the aimed porous silica particles having uniform pores while keeping the crystal skeleton of the compound. Since the resultant particles have a high specific surface area, they can be utilized for wide applications, e.g. adsorbents, drying agents, catalysts, catalyst carriers, insulating agents, etc.

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Industrial 7) IF4J#I field) This invention is a Caine calcium compound with various performances such as g & NI, drying, catalyst, insulation, etc. 7) Retaining crystalline form. Ma\uniform 7) Neko? The formed porous D silica number 7)
There is also a part C regarding the manufacturing method.

(Prior art) The conventional method for producing silica gel D is to add sulfuric acid to sodium silicate to gel the mixture, and then add sodium sulfate as a reaction product. It was removed by thorough washing and dried to form a glassy D-silica gel. However, in conventional manufacturing methods, pores are formed by evaporation of water during the dehydration process, so pores are uniform! 2, and there is a limit to the direction of the specific surface area due to the pore formation mechanism.
Furthermore, since the trick method involves gelation, it was not possible to disperse silica powder 2 without pulverizing it after drying.

(@Akatsu's problem to be solved) 7) In view of the above circumstances, the invention was designed to create uniform pores, which was difficult with conventional technology! It solves the problem of difficulty in forming il- and improves the specific surface area by forming uniform and ultra-fine pores, while also making it porous and easily dispersible without becoming rough or gelling. D also provides a manufacturing method for obtaining porous silica particles.

[Invented configuration]

(Means for Solving Problems) In order to achieve the above-mentioned object, the present invention is based on adding water to a calcium silicate compound to form a slurry, stirring it, and adding hydrochloric acid or nitric acid to the solution. Addition of hydrochloric acid or nitric acid added in the reaction to dissolve the calcium content ff1E Add liqueur so that the neutralization ratio is 1.0 or more and 1.1 or less, and then stir and bind for 60 minutes to convert into calcium. Calcium silicate compound 2 is selectively dissolved, solid-liquid separated, and then thoroughly washed and dried to form a crystalline form of calcium silicate compound. While retaining uniform pores and ``large porous silica particles'', there are 7)?' There is a value C that is calculated by dividing 1 minute of calcium chloride by the weight of acid required to theoretically neutralize it.

In addition, the concentration of the calcium silicate compound D slurry used in this D invention is preferably 3 to 15N%.
If it is less than 15% by weight, it will be economically disadvantageous, whereas if it is more than 15% by weight, the calcium content in the calcium silicate compound? This is not preferable because the dissolution reaction becomes non-uniform.

Again -%tj! The acid used is preferably hydrochloric acid or nitric acid, which reacts with the calcium content of the calcium silicate compound to form a water-soluble salt. % is most preferable.

Regarding the reaction temperature in the dissolution reaction in which acid 2 is added to the calcium silicate compound slurry, it is sufficient to start at room temperature (7), but it is also possible to conduct it in a heated and concentrated state (C), and the reaction speed can be improved by setting the reaction temperature to the boiling point. and a reduction in the amount of impurities in the reaction product can be expected.

(Saku's condolence) To explain this D invention's effect, is it an acid addition company in the reaction to dissolve the calcium in the calcium silicate compound? By setting the neutralization ratio to 1.0 or more and 1.1 or less, it is possible to maintain the calcium silicate compound crystal form and dissolve the calcium content, so that the product is not a colloidal Kr liquid. The calcium in the crystals dissolves without becoming a gel! This allows three uniform pore shapes to be formed.

In addition, by using this technique, it is possible to impart and activate a high specific surface @ 7), and furthermore, since it retains the crystal structure, it can be easily dispersed, and it can be used for various purposes and has great effects. is large.

(Example) Various D examples related to the method for producing frJJD porous silica particles will be described below, as well as the nX-ray diffraction results and specific surface of the products soaked from these D examples! ! ! The results of the two measurements are summarized and shown in the attached table.The calcium silicate compound samples used in these Examples D were prepared using the following manufacturing method7). Namely, silicic acid powder (average particle size 5μ) and slaked lime powder (industrial slaked lime J Engineering S name)
and OaO/810.2 were mixed uniformly so that the molar ratio was 1.0, and the mixture was heated to 200"0(15)C in an autoclave.
9/cj) 73 conditions? ? The calcium silicate compound was removed by reacting for 10 hours, and the calcium silicate compound was crushed and divided into pieces of 20 μm or less.

Sample 7) The result of X-ray diffraction was that it was zodrite and no D-beak appeared.

In addition, the specific surface area measurement result by nitrogen adsorption EICT method is 2.
3. There was a lot of fui/q.

- Example 1287 ml of water in a 733 ton glass beaker,
Add sample 1439f to create a slurry with a concentration of 10% by weight, and stir with a plastic stirring blade (rotation speed: 3001PM).
), 79 mounds of 20% D nitric acid was added dropwise over 5 minutes to give a neutralization equivalence ratio of 1.05, and the mixture was stirred for 60 minutes over 4 tubes. 1. After filtration, wash thoroughly with water to remove Cl711' soluble salts 150'
Porous silica particles f were obtained by drying for 6 hours.

2nd Example Porous A silica was prepared under the same conditions and operations as in the Happy Example except that the acid was changed from nitric acid to hydrochloric acid and 4602 ml of hydrochloric acid with a concentration of 20iλ% was added to give a ratio of 1.05 during neutralization. It's a disgrace to particles.

Third Embodiment The concentration is 15 mA so that the neutralization ratio is 1.1! The porous silica particles were spread under the same conditions and operations as in the first row except that 99f of nitric acid LIO was added. The filtrate after filtration turned into a gel after being left to stand for 2 hours.The gel product was filtered and After washing, dry at 150℃ for 5 hours and measure specific surface area and XU diffraction 2
The results are a disgrace because the conduct is not shown in the attached table.

Attached Table 1tE) The specific surface area of conventional silica gel D is 650 trepi.

[Invention effect]

This D invention has the following advantages in accordance with the above 7).

(1) By limiting the amount of acid added in the reaction of dissolving calcium silicate compounds with calcium minate acid, the crystalline form of the calcium silicate compounds can be maintained, and the calcium silicate compounds can be dissolved by calcium dissolution. Porous silica particles having 2q'r of uniform coarse pores are provided.

(2) Furthermore, the porous silica particles, which are the product of this D invention, can be easily dispersed by D while retaining the silicic acid compound'D crystal skeleton, and uniform fine pores can be formed. 7) To have a high specific surface area.

(3) The porous silica particles of the present invention have the following performance 2.
7J'c adsorbent, desiccant, catalyst, catalyst support.

It is highly effective and can be used in a wide range of applications such as filling agents, RGR heating agents, insulation materials, and raw materials for high-purity silica.

4. Drawing 7) I! detailed explanation No drawings.

Procedural amendment (u) October 2, 1985 (To the Chief Examiner of the Japan Patent Office) (To the Examiner of the Japan Patent Office) 1. Indication of the case 1985 Patent No. 181513 2. Title of the invention Porous silica particles Manufacturing method 3, relationship with the case of the person making the amendment Patent applicant 4, attorney 6, number of inventions increased by the amendment We have amended the specification of the application as follows, [Page 1, lines 5 to 10] Line 6 of the claims in line 6 “Neutralization equivalent ratio 1.0 or more and 1.1 or less・* @ J f
Correct it as "neutralization equivalent ratio 1.0 or more and 1.3 or less..." ◎ Therefore, the full text after the correction is as follows ◎ "Neutralization equivalent ratio of calcium silicate compound in the presence of water Production of porous silica particles characterized by forming uniform pores while retaining their crystal form by adding hydrochloric acid or nitric acid of 1.0 to 1.3 to dissolve the calcium content. 2. On page 3, line 9 of ts, "041 bone that is 1.0 or more and 1.1 or less" is corrected to "l, o or more, 3 or less...".

6, Takashi page 5, line 3 “…neutralization equivalent ratio 1.0 or more 1
．． 1" is corrected to "...neutralization equivalent ratio 1.0 or more, 1.3."

4. Page 6, lines 5 to 46, “The molar ratio is 1.
The supplementary sentence ``without adding water'' is added between ``so that the temperature is 0°'' and ``mix evenly...'' Therefore, the corrected sentence becomes as follows.

"LGI uniformly without adding water f so that the molar ratio is 1.0..." 5, page 7, line 17 "The neutralization equivalent ratio is 1.2.
-" and "The neutralization equivalent ratio becomes 1.4...j and correction "Rukuchi 6, page 7, line 17, 100" of nitric acid 12109..."
is corrected as "nitric acid 1412...".

7, #i Page 8 Fu Lines 6 to 16 of the attached table, end line 13 to l! ! The neutralization equivalent ratio of 1.2 in the fourth embodiment described in the column spanning the 14th line is corrected to 1.4.

that's all

Claims (1)

[Claims] By adding hydrochloric acid or nitric acid with a neutralization equivalent ratio of 1.0 to 1.1 to a calcium silicate compound in the presence of hydraulic power to dissolve the calcium content, uniform pores are formed while retaining the crystal structure. A method for producing porous silica particles, characterized by forming porous silica particles.