JPH09241021A - Calcium aluminate tricarbonate hydrate and synthesis - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrially useful and efficient synthesis of a high purity calcium aluminate tricarbonate hydrate capable of using for a filler for making paper. SOLUTION: The calcium aluminate tricarbonate hydrate has the aspect ratio of <=50. And the synthesis is by mixing an alkali aluminate and/or aluminum hydroxide, a carbonate, calcium hydroxide and an organic compound and further, if necessary an alkali metallic hydroxide with water or mixing aluminum oxide, the alkali metallic hydroxide, the carbonate and the organic compound with water to allow to react with each other.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a calcium aluminate tricarbonate hydrate that can be used as a filler for papermaking and the like, and a method for synthesizing the same.

[0002]

Formula _{3CaO · Al 2 O 3 · 3CaSO} 4 · 32H calcium aluminate tri sulfate hydrate represented by ₂ O (ettringite) are known as useful inorganic compound of the Prior Art and Its Problems] papermaking filler (JP Sho
53-14692, Hiroshi Yamada; Ceramics; 17, p159-16
3,1982).

On the other hand, as an inorganic compound similar to calcium aluminate trisulfate hydrate, calcium aluminate tricarbonate hydrate, which is a general term for compounds represented by the chemical formula 3CaO.Al ₂ O ₃ .3CaCO ₃ .32H ₂ O, is known. However, no industrial benefit has been found so far (Elmer T. Carlson and Horace
A.Berman ； JOURNAL OF RESEARCH of the National Bure
au of Standards-A. Physics and Chemistry; Vol.64A, N
o.4, p333-341, 1960).

Conventionally, as a method for synthesizing this calcium aluminate tricarbonate hydrate, a method in which a calcium aluminate-containing solution is mixed with a carbonate and sugar and reacted, or calcium chloride, an alkali aluminate salt, and a carbonate salt A method for reacting water in water was proposed (Elmer T. Carlson and Horace A. Berman; JOURNAL
OF RESEARCH of the National Bureau of Standards-A.
Physics and Chemistry; Vol.64A, No.4, p333〜341,196
0, Ren Yasue, Kensuke Kanai, Yoshiyuki Kojima, Yasuo Arai; Journal of the Ceramic Society of Japan; Vol.100, No.8, p1053 ~ 1059,1
992). However, in any of the methods, there is a problem that the compound is thin and only a very small amount can be obtained. In addition, in the method of reacting calcium chloride or the like, there is a problem that it is difficult to use it as a paper-making filler because chlorine is solid-dissolved or adheres, and therefore, the conventional method for synthesizing calcium aluminate tricarbonate hydrate is industrial. It wasn't helpful.

As a result of extensive studies, the present inventor has been able to efficiently produce calcium aluminate tricarbonate hydrate by a specific synthesis method at a relatively low cost, and has a calcium aluminate trihydrate having an aspect ratio of 50 or less. The inventors have found that carbonate hydrate can be synthesized, and completed the present invention.

[0006]

Means for Solving the Problems That is, the present invention is a calcium aluminate tricarbonate hydrate characterized by having an aspect ratio of 50 or less, and an aluminate alkali salt and / or aluminum hydroxide, carbonate. , Calcium hydroxide, and an organic compound, if necessary, by further mixing an alkali metal hydroxide in water, aluminum oxide, an alkali metal hydroxide,
It is a method for synthesizing calcium aluminate tricarbonate hydrate in which carbonate, calcium hydroxide, and an organic compound are mixed and reacted in water.

The present invention will be described in detail below.

Calcium aluminate tricarbonate hydrate (hereinafter referred to as CATCH) has the chemical formula
Since it is a compound represented by 3CaO.Al ₂ O ₃ .3CaCO ₃ .32H ₂ O and is registered in JCPDS as a card number 18-277, it can be easily identified by an X-ray diffraction method. The aspect ratio of CATCH according to the present invention is 50 or less,
20 or less is preferable, and 10 or less is more preferable. If the aspect ratio exceeds 50, the dispersibility of CATCH may deteriorate. Here, the aspect ratio usually indicates the ratio of the vertical dimension (length) to the horizontal dimension (width or diameter) of the crystal, and a large aspect ratio indicates a thread shape. The aspect ratio can be calculated by observing and measuring the crystal with an electron microscope. In the present invention, CATCH
The presence of impurities generated during the synthesis of is not particularly limited, and for example, even if some calcium carbonate, calcium hydroxide, aluminum hydroxide, and calcium aluminate hydrate are by-produced, they are used. It is possible.

The alkali aluminate salt used in the present invention is represented by the chemical formula Al ₂ O ₃ .mR ₂ O (R is an alkali metal, and m is usually about 0.5 to 2). Include sodium aluminate, potassium aluminate, lithium aluminate, and the like, and one or more of them can be used in the present invention. In addition, some aluminate aluminates have water of crystallization in a range of 10 mol or less, and any of them can be used in the present invention. The amount of the alkali aluminate salt used is not particularly limited, and it is preferable to use it in the range of the CO ₃ / Al molar ratio in the suspension obtained by mixing the alkali aluminate salt and the carbonate. Alkaline aluminate is usually 0.
Use at a concentration of 1-2 mol / l. If it is less than 0.1 mol / liter, the amount of CATCH synthesized will be small, and it will not necessarily be industrially beneficial. If it is higher than 2 mol / liter, the reaction liquid will become extremely viscous and agitated.
Mixing may be difficult.

The aluminum hydroxide used in the present invention is a general term for compounds represented by Al (OH) ₃ and Al ₂ O ₃ .H ₂ O, and is not particularly limited, and crystalline or Any use of amorphous is possible.

In the present invention, alkali aluminate and /
Alternatively, when aluminum hydroxide, particularly aluminum hydroxide is used, it is preferable to use an alkali metal hydroxide together in order to accelerate the synthesis of CATCH. When the alkali metal hydroxide is used in combination, it is preferable to immerse the alkali aluminate salt and / or aluminum hydroxide in an aqueous solution of alkali metal hydroxide. The temperature of the aqueous solution of the alkali metal hydroxide in this case is not particularly limited, but is preferably 30 to 80 ° C, more preferably 40 to 60 ° C. Here, the alkali metal hydroxide is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide, and lithium hydroxide, and it is possible to use one or more of these. Is.

The aluminum oxide used in the present invention is
It is a generic term for compounds represented by Al ₂ O ₃ , and is not particularly limited, and either crystalline or amorphous can be used, and industrially, bauxite, clayey substance, and aluminum are used. Residual ash, etc. can be used. It is necessary to use aluminum oxide after immersing it in an aqueous solution of an alkali metal hydroxide in advance in order to accelerate the synthesis of CATCH. The temperature of the aqueous solution of the alkali metal hydroxide in which the aluminum oxide is dipped is not particularly limited, but is preferably 30 to 80 ° C, more preferably 40 to 60 ° C.

The carbonates used in the present invention include alkali metal carbonates such as sodium carbonate, potassium carbonate, lithium carbonate and potassium sodium carbonate, and alkali metal bicarbonates such as sodium bicarbonate, potassium bicarbonate and lithium bicarbonate. Examples thereof include carbonates and ammonium salts such as ammonium carbonate and ammonium bicarbonate, and one or more of these can be used. Further, among these carbonates, there are anhydrous salts and hydrous salts, but any of them can be used in the present invention.

The calcium hydroxide used in the present invention is not particularly limited, and reagents and industrial raw materials can be used, and it is an industrially inexpensive material. Although calcium oxide can be used in the present invention, it is preferable to use calcium hydroxide from the viewpoint of safety.

The organic compound used in the present invention is not particularly limited, and examples thereof include sugars such as monosaccharides and polysaccharides, citric acid, tartaric acid, gluconic acid, malic acid, lactic acid,
Organic acids such as formic acid, acetic acid, and salicylic acid or salts thereof, amine compounds such as monoethanolamine, diethanolamine, and triethanolamine, amino acids such as glycine, urea, and hexamethylenetetramine, and the like. One or more of them can be used, but it is preferable to use relatively inexpensive saccharides, organic acids or salts thereof.

In the present invention, an alkali aluminate salt and / or
Alternatively, aluminum hydroxide, a carbonate, and a suspension in which an organic compound and an alkali metal hydroxide, which is mixed as necessary, are mixed, and aluminum oxide, an alkali metal hydroxide, a carbonate, and an organic compound. Or a mixture of the suspension and calcium hydroxide to react or
A suspension prepared by mixing an aluminate alkali salt and / or aluminum hydroxide with a carbonate, and optionally an alkali metal hydroxide, and a suspension prepared by mixing aluminum oxide, an alkali metal hydroxide and a carbonate. It is possible to react by mixing the suspension with calcium hydroxide and an organic compound. At this time, it is preferable to preliminarily disperse calcium hydroxide in water to form a slurry, and it is more preferable to mix an organic compound with this slurry.
Among them, in the present invention, a suspension prepared by mixing an aluminate alkali salt and / or aluminum hydroxide and a carbonate, and if necessary, an alkali metal hydroxide, aluminum oxide, an alkali metal hydroxide, and It is more preferable that a suspension obtained by mixing a carbonate and a slurry containing calcium hydroxide and an organic compound are mixed and reacted. Alkali aluminate and / or aluminum hydroxide, or a mixture of aluminum oxide and calcium hydroxide, and then a carbonate to react, a kind of calcium aluminate hydrate called hydrogarnet or calcium carbonate. When a carbonate and calcium hydroxide are mixed and then an aluminate alkali salt and / or aluminum hydroxide is mixed and reacted, calcium carbonate is easily generated and the purity of CATCH is lowered. There is a case.

Further, according to the present invention, an alkali aluminate salt and aluminum hydroxide, particularly aluminum hydroxide,
It is preferable to preliminarily immerse in an aqueous solution of an alkali metal hydroxide and treat with an alkali metal hydroxide, and it is necessary to use aluminum oxide together with the alkali metal hydroxide. When alkali metal aluminate, aluminum hydroxide, or aluminum oxide is used in combination with alkali metal hydroxide, the synthesis of CATCH tends to be accelerated.

In the present invention, the mixing ratio of each of the alkali aluminate and the aluminum hydroxide is not particularly limited, and the alkali aluminate and / or the aluminum hydroxide and the carbonate may be further added. CO ₃ / in suspension mixed with alkali metal hydroxide accordingly
It is preferable to use Al in a molar ratio of 0.7 or less. The concentration of the alkali aluminate salt and / or aluminum hydroxide is not particularly limited, but is usually 0.1 to 2 mol / liter. If it is less than 0.1 mol / liter, the amount of the product obtained is small and it is not industrially useful. If it is used in excess of 2 mol / liter, the viscosity of the reaction solution becomes extremely large, which may make the synthesis of CATCH difficult.

The amount of the alkali metal hydroxide used is not particularly limited, but it is preferably 10 to 200 parts by weight with respect to 100 parts by weight of the alkali aluminate salt and / or aluminum hydroxide or aluminum oxide, More preferably 50 to 150 parts by weight. If it is less than 10 parts by weight, the amount of CATCH synthesized may be small, and even if it is used in excess of 200 parts by weight, further increase in effect cannot be expected.

The amount of the carbonate used is not particularly limited, and it may be used in a suspension prepared by mixing an alkali aluminate and / or aluminum hydroxide with a carbonate and, if necessary, an alkali metal hydroxide. In addition, aluminum oxide, alkali metal hydroxide, and carbonate in a mixed suspension
It is preferable to use it in the range where the CO ₃ / Al molar ratio is 0.7 or less. The concentration of carbonate is usually 0.1 to 2 mol / liter. If it is less than 0.1 mol / liter, the amount of the obtained compound is small, which is not industrially useful. If it is used in excess of 2 mol / liter, the viscosity of the reaction solution becomes extremely large and C
It may be difficult to synthesize ATCH.

The amount of calcium hydroxide used is not particularly limited, and it may be a suspension prepared by mixing an alkali aluminate salt and / or aluminum hydroxide with a carbonate salt and, if necessary, an alkali metal hydroxide. In addition, in a reaction system in which a suspension obtained by mixing aluminum oxide, an alkali metal hydroxide, and a carbonate is mixed with calcium hydroxide.
The Ca / Al molar ratio is preferably 1.5 or less. The concentration of calcium hydroxide is usually 0.1-2mo
l / liter. If less than 0.1 mol / l, the amount of synthetic compound obtained is too small, which is not industrially beneficial.
If it is used in excess of 1 liter, the viscosity of the reaction solution becomes extremely large, which may make it difficult to synthesize CATCH.

The amount of the organic compound used is preferably 0.1 to 10 parts by weight, and 1 to 5 parts by weight, based on 100 parts by weight of the total of water and the organic compound.
Parts by weight are more preferred. CATCH less than 0.1 part by weight
In some cases, calcium aluminate monocarbonate hydrate (CAMCH) is produced without the formation of
If it exceeds the weight part, the cost becomes high, which is not preferable.

The amount of water used is not particularly limited, but the concentration range of the above-mentioned alkali aluminate salt, aluminum hydroxide, carbonate and calcium hydroxide, that is,
Usually, it is preferable to select in the concentration range of 0.1 to 2 mol / liter.

In the present invention, an alkali aluminate salt and / or
CO in a suspension prepared by mixing aluminum hydroxide and a carbonate, and optionally an alkali metal hydroxide, or in a suspension prepared by mixing aluminum oxide, an alkali metal hydroxide and a carbonate. The molar ratio of ₃ / Al is preferably 0.7 or less, more preferably 0.5 or less. The CO ₃ / Al molar ratio is 0.
If it exceeds 7, the amount of by-produced calcium carbonate may increase.

The Ca / Al molar ratio in the reaction system mixed with calcium hydroxide is preferably 6 or less, more preferably 3 or less. When the molar ratio of Ca / Al in the reaction system exceeds 6, unreacted calcium hydroxide may remain.

In the present invention, the reaction temperature is preferably maintained at about 10-40 ° C, more preferably 20-30 ° C. If the reaction temperature is lower than 10 ° C, the production rate of CATCH is slow, and if it exceeds 40 ° C, the production of calcium carbonate may increase.

Further, in the present invention, after the reaction, it is preferable to leave it for 1 hour or more for aging, and more preferably for 4 hours or more. The CATCH obtained without aging has low crystallinity, and unreacted calcium hydroxide may remain.

[0028]

The present invention will be described below in more detail with reference to examples.

Example 1 A suspension prepared by mixing an alkali aluminate salt and a carbonate salt shown in Table 1 with 1 liter of a 5% by weight aqueous solution of an organic compound b,
5% by weight of calcium hydroxide shown in Table 1 of organic compound B
After stirring for 30 minutes each with a slurry mixed with 1 liter of an aqueous solution, and then aging at 25 ° C. for 4 hours, the precipitate was filtered, washed with water, dried at 30 ° C., and then synthesized. Got The obtained composite was identified by the powder X-ray diffraction method (XRD) and observed and measured with an electron microscope to calculate the aspect ratio. The results are also shown in Table 1. For comparison, the results when calcium aluminate (CA) is used instead of alkali aluminate are also shown.

<Materials to be used> Alkali aluminate α: sodium aluminate, first grade reagent, Al ₂ O ₃ · 1.5Na ₂ O · 4.7H ₂ O Alkali acid aluminate β: potassium aluminate, reagent 1
Grade, trihydrate, Al ₂ O ₃ · 1.2K ₂ O · 3H ₂ O carbonate a: sodium carbonate, reagent first grade carbonate b: sodium carbonate, reagent first grade, 10 hydrate carbonate c: carbonate Sodium hydrogen, reagent 1st grade carbonate d: potassium carbonate, reagent 1st grade carbonate e: lithium carbonate, reagent 1st grade carbonate f: ammonium hydrogencarbonate, reagent 1st grade calcium hydroxide: reagent 1st grade Organic compound a: commercially available Sugar CA: Commercially available alumina cement water: Tap water

[0031]

[Table 1]

Example 2 Alkali aluminate α 0.5 mol, carbonate a 0.5 mol,
And 2.0 mol of calcium hydroxide were used, and the same procedure as in Example 1 was carried out except that the kind and the amount of the organic compound used were changed as shown in Table 2. The results are also shown in Table 2.

<Materials used> Organic compound (b): lactic acid, reagent first grade Organic compound (c): citric acid, reagent first grade Organic compound (d): malic acid, reagent first grade Organic compound (e): salicylic acid, reagent first grade organic compound f: tri Ethanolamine, first-grade reagent Organic compound: urea, first-grade reagent

[0034]

[Table 2]

Example 3 A suspension prepared by mixing aluminum hydroxide and carbonate shown in Table 3 in 1 liter of a 5% by weight aqueous solution of organic compound a and calcium hydroxide shown in Table 3 in an amount of 5 parts by weight of organic compound a. % Slurry mixed with 1 liter of aqueous solution for 30 minutes each, and then mixed and aged at 25 ° C for 24 hours. After aging, the precipitate was filtered, washed with water, dried at 30 ° C and synthesized. The same procedure as in Example 1 was performed except that the product was obtained. The results are also shown in Table 3. For comparison, the results when CA is used instead of aluminum hydroxide are also shown.

<Materials used> Aluminum hydroxide: first-grade reagent, Al (OH) ₃

[0037]

[Table 3]

Example 4 1 mol of aluminum hydroxide and an alkali metal hydroxide shown in Table 4 were mixed with 1 liter of a 5% by weight aqueous solution of organic compound a, stirred for 30 minutes, and then mixed with 1 mol of carbonate a. The obtained suspension was mixed with a slurry prepared by mixing 2 mol of calcium hydroxide with 1 liter of a 5% by weight aqueous solution of organic compound (1), followed by aging at 25 ° C. for 2 hours. After aging, the precipitate was filtered and washed with water. The same procedure as in Example 1 was carried out, except that the compound was obtained by washing with water and drying at 30 ° C. The results are also shown in Table 4.

<Materials used> Alkali metal hydroxide A: sodium hydroxide, reagent grade 1 Alkali metal hydroxide B: potassium hydroxide, reagent grade 1 Alkali metal hydroxide C: lithium hydroxide, reagent grade 1

[0040]

[Table 4]

Example 5 The same as Example 4 except that aluminum hydroxide, alkali metal hydroxide A, and carbonate a were used, and the kind and amount of the organic compound used were changed as shown in Table 5. went.
Table 5 shows the results.

[0042]

[Table 5]

Example 6 Aluminic acid alkali salt α 0.25 mol, aluminum hydroxide
A suspension obtained by mixing 0.5 mol of the carbonate shown in Table 6 with 1 liter of a 5 wt% aqueous solution of organic compound a and calcium hydroxide shown in Table 6 with 1 liter of a 5 wt% aqueous solution of organic compound a were mixed. After stirring and mixing with the slurry for 30 minutes each, the mixture was aged at 25 ° C for 8 hours, and after the aging, the precipitate was filtered, washed with water, and dried at 30 ° C to obtain a compound. The same procedure as in Example 1 was performed. The results are also shown in Table 6.

[0044]

[Table 6]

Example 7 A suspension prepared by mixing 0.5 mol of aluminum oxide, an alkali metal hydroxide shown in Table 7 and a carbonate in 1 liter of a 5% by weight aqueous solution of organic compound a and a hydroxide shown in Table 7. The same procedure as in Example 1 was carried out except that a slurry prepared by mixing calcium with 1 liter of a 5% by weight aqueous solution of organic compound B was used. The results are also shown in Table 7. For comparison,
The results when CA is used instead of aluminum oxide are also shown.

<Materials used> Aluminum oxide: first grade reagent

[0047]

[Table 7]

Example 8 The same procedure as in Example 7 was carried out except that aluminum oxide, alkali metal hydroxide A, and carbonate a were used, and the kind and amount of the organic compound used were changed as shown in Table 8. It was The results are also shown in Table 8.

[0049]

[Table 8]

[0050]

Industrial Applicability The method of the present invention is industrially beneficial, efficient,
It has effects such as high purity and the ability to synthesize needle-like or columnar fine crystals of CATCH.

Claims (4)

[Claims] 1. A calcium aluminate tricarbonate hydrate having an aspect ratio of 50 or less. 2. A method for synthesizing calcium aluminate tricarbonate hydrate, which comprises mixing an alkali aluminate and / or aluminum hydroxide, a carbonate, calcium hydroxide and an organic compound in water to react them. . 3. A calcium aluminate try characterized by mixing an alkali aluminate and / or aluminum hydroxide, an alkali metal hydroxide, a carbonate, calcium hydroxide, and an organic compound in water and reacting them. Method for synthesizing carbonate hydrate. 4. A method for synthesizing calcium aluminate tricarbonate hydrate, which comprises mixing aluminum oxide, an alkali metal hydroxide, a carbonate, calcium hydroxide, and an organic compound in water to cause a reaction.