JPH0130765B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a magnesium aluminum hydrated basic carbonate.

Magnesium aluminum hydrous basic carbonate (hereinafter simply referred to as basic carbonate) is a well-known natural product produced in the Snarm region of Norway, but it contains many impurities and has poor quality. It is not constant and its purification is difficult. In recent years, basic carbonates have come to be used in large quantities as pharmaceutical antacids, adsorbents, etc., and various synthetic methods have therefore been developed to obtain highly pure products. The following methods are known as typical synthetic methods.

(i) Water or lower alcohol soluble aluminum salts (aluminum sulfate, aluminum chloride,
Aluminum nitrate, aluminum acetate, etc.) and magnesium salts (magnesium sulfate, magnesium chloride, magnesium nitrate, etc.) and carbonates (sodium carbonate, sodium hydrogen carbonate, potassium carbonate, etc.) or carbon dioxide gas in a caustic alkali (sodium hydroxide, potassium hydroxide, etc.) etc.) in water and/or a lower alcohol.

(ii) (a) an insoluble aluminum hydroxide or basic salt; and (b) magnesium oxide, magnesium hydroxide and magnesium carbonate;
When (b) does not contain CO ₃ ^-2 , further (c) carbon dioxide gas or carbonate is reacted by heating in water.

However, in method (i) above, the process is complicated because a wide variety of raw materials are used, and a large amount of reaction by-products such as sodium chloride, sodium sulfate, sodium acetate, and sodium nitrate are produced, which contribute to the desired reaction. Since it is adsorbed or included in the product, its removal requires a large amount of water and time, which has the disadvantage of increasing manufacturing costs. In method (ii) above, since the reaction proceeds relatively slowly, it takes a long time to complete the reaction, which inevitably increases production costs.

As a result of repeated research in order to solve the drawbacks of the conventional method as described above, the inventor of the present invention has found that the process can be simplified by carrying out a solid-liquid reaction between basic magnesium carbonate and alkali aluminate in an alkaline region. The present inventors have discovered that the reaction speeds up and the amount of by-product impurities is significantly reduced, leading to the completion of the present invention. That is, the present invention has the general formula Mg _x Al _y (OH) _2x , which is characterized by reacting basic magnesium carbonate powder or paste with an alkali aluminate at a temperature of 20 to 100°C while stirring in an aqueous medium. _+3y-2z (CO ₃ ) _z・nH ₂ O () [However, x and y are positive numbers that satisfy 1.5≦x/y≦4.1, z is a positive number that satisfies 0.8≦z≦3.0, n
is a positive number satisfying 2.9≦n≦5.3] This relates to a method for producing a magnesium aluminum hydrated basic carbonate.

In the present invention, since the alkaline substances are reacted in an alkaline region, there were concerns that a large amount of free alkali would be produced and this would affect the reaction products, but in reality, as the reaction progresses, The pH of the area decreases and becomes only slightly alkaline. This was bound to basic magnesium carbonate, for example, by the reaction shown below.
It is presumed that as the reaction progresses, CO ₃ ^2- dissociates into the solution and neutralizes the alkali in the solution, resulting in a decrease in PH.

8NaAlO ₂ +6 {Mg ₄ (OH) ₂ (CO ₃ ) ₃・4H ₂ O
}+18H ₂ O → 4 {Mg ₆ Al ₂ (OH) ₁₆ CO ₃・4H ₂ O}+4Na
₂ BCO ₃ +10CO ₂ ↑ The basic carbonate of the general formula () obtained by the present invention is not a mere mixture of aluminum hydroxide and basic magnesium carbonate, but is a crystalline substance as is clear from the X-ray diffraction results. Or it is a coprecipitate of crystalline material and basic magnesium carbonate.

The method of the present invention is carried out, for example, as follows. Add water to basic magnesium carbonate powder or paste and stir until the concentration as MgO is 0.2.
Prepare a ~5% suspension and adjust the temperature to 20~100℃
An aqueous alkali aluminate solution (concentration as Al ₂ O ₃ of 2 to 25
%) little by little and react while stirring.

The ratio (molar ratio) of hydroxyl groups to carbonate groups in basic magnesium carbonate is preferably in the range of OH ^- /CO ₃ ^2- = about 0.4 to 8. If the molar ratio of OH ^- /CO ₃ ^2- is too low, the reaction will be slow and the amount of basic magnesium carbonate coprecipitated will increase. On the other hand, if it is too high, the amount of free alkali after the reaction will increase, making it necessary to supply the required CO ₂ by other means. In the present invention, it is preferable to use a paste obtained by washing with water after the production of basic magnesium carbonate because the reaction rate is higher. When using powder, it is desirable to adjust the particle size to 150 μm or less.

As the alkali aluminate, sodium aluminate and potassium aluminate are practically advantageous. Particularly from the point of view of cost, it is advantageous to use sodium aluminate, which is available as an inexpensive commercially available aqueous solution.

The quantitative ratio (molar ratio) of basic magnesium carbonate and alkali aluminate is preferably set to Mg/Al = about 1.5 to 4.1.

After the reaction is completed, the generated precipitate is filtered, washed with water, dehydrated, dried and crushed to obtain the basic carbonate of the present invention represented by the general formula (). This basic carbonate exhibits excellent antacid power of over 260ml in the antacid test according to the Japanese Pharmacopoeia. In addition, as an acid adsorbent, the phthalic acid adsorption capacity is 4.0meq/g or more,
This is activated carbon (1.8 meq/
g), which is an extremely high value compared to activated clay (0.1 meq/g) and bentonite (1.0 meq/g). Furthermore, 4% of the present invention was added to a 50% brown sugar aqueous solution,
When treated at 60°C for 30 minutes, the decolorization rate was 70%. Decolorization rate of diatomaceous earth under the same conditions is 6%
Therefore, the excellent effects of the product of the present invention are clear. Furthermore, the product of the present invention exhibits excellent performance as a super-aiding agent.

According to the method of the present invention, the following remarkable effects can be obtained.

(b) Since only two types of raw materials are used, the process is simplified and manufacturing costs are reduced.

(b) Since the process is simple, there is no need for complicated process control, and the quality of the product is stable.

(c) Since it is a method based on an alkali-alkali reaction,
Fewer by-product impurities. Therefore, the amount of water required for its removal is small, the manufacturing time is short, and costs can be reduced.

(d) Since the method is based on a solid-liquid reaction, there are fewer impurities in the product, and the homogeneity and purity of the reaction product are greatly improved.

(e) The obtained product exhibits excellent performance as an antacid, acid adsorbent, decolorizing agent, superagent, catalyst carrier, etc.

Hereinafter, the features of the present invention will be further clarified through Examples.

Example 1 Basic magnesium carbonate paste (OH ^- /
Add 1300 g of CO ₃ ^2- = 0.625 (molar ratio), MgO content 6.4%, water content 85%) to the stirring sewage 3, and adjust the pH
10.0, and while heating and maintaining this at 80°C, add a sodium amate aqueous solution (Al ₂ O ₃ content 20%,
After gradually pouring 205 g (pH 14 or higher) into the mixture, the reaction was continued at the same temperature for 1 hour with stirring. Final reaction solution
The pH was 8.5. After the reaction was completed, the precipitate was separated from the mother liquor by filtration, washed with water, dehydrated, dried at 80°C, and crushed to obtain 220 g of product.
The analysis results and various physical properties of the product were as follows.

MgO 36.9% Analysis value Al ₂ O ₃ 18.2% CO ₂ 9.1% Na 0.01% Loss on drying (105℃, 3 hours) 1.7% Loss on ignition (900℃, 3 hours) 44.8% PH of 4% suspension 8.82 Japan Antacid power according to pharmacopoeia 280ml Phthalate adsorption capacity (0.05N phthalate DOP solution, 100
℃, 1 hour treatment) 5.4meq/g Composition formula Mg _5.13 Al ₂ (OH) _13.94 (CO ₃ ) _1.16・3.6H ₂ O X-ray diffraction diagram of the product obtained in this example (measurement conditions: Cu-K , 30KV, 10mA, 2θ=5° to 65°) is shown in Figure 1.

Example 2 Basic magnesium carbonate paste (OH ^- /
Add 1300 g of CO ₃ ^2- = 7.2 (mole ratio), MgO content 6.2%, water content 89%) to stirring sewage 3 to make a suspension of pH 10.3, and while heating and maintaining this at 80°C, aluminium Aqueous sodium acid solution ( _Al2O3 content 20%, _PH14
After gradually adding 185 g of the above solution, the reaction was continued at the same temperature for 30 minutes with stirring. The final pH of the reaction solution is
It was 10.4. The precipitate was separated, washed with water, dehydrated, dried at 80°C, and crushed to obtain 205 g of product.
The analysis results and various physical properties of the product were as follows.

MgO 38.5% Analysis value Al ₂ O ₃ 17.7% CO ₂ 8.9% Na 0.005% Loss on drying (105℃, 3 hours) 1.6% Loss on ignition (900℃, 3 hours) 43.6% PH of 4% suspension 8.53 Japan Antacid power according to pharmacopoeia 278ml Phthalate adsorption capacity (0.05N phthalate DOP solution, 100
℃, 1 hour treatment) 5.2meq/g Composition formula Mg _5.49 Al ₂ (OH) _14.66 (CO ₃ ) _1.16・3.28H ₂ O The X-ray diffraction results of the product obtained in this example are the same as in Example 1. It was the same.

Example 3 Basic magnesium carbonate powder (OH ^- /CO ₃ ^2- =
0.5 (mole ratio), MgO content 42%) 50g was stirred into sewage.
In addition to 600 ml, a suspension with a pH of 9.2 was prepared. While maintaining the resulting suspension at 80°C, add 45 g of sodium aluminate aqueous solution (Al ₂ O ₃ content 20%, PH 14 or higher).
was gradually added, and the reaction mixture was maintained at the same temperature for 2 hours with stirring, and the final pH of the reaction solution was 9.5. After separating the precipitate in the reaction solution, washing with water, dehydrating, and drying at 80°C,
It was crushed to obtain 55 g of product. The analysis results and various physical properties of the obtained product are shown below.

MgO 36.3% Analysis value Al ₂ O ₃ 15.7% CO ₂ 15.9% Na 0.01% Loss on drying (105℃, 3 hours) 1.9% Loss on ignition (900℃, 3 hours) 47.8% PH of 4% suspension 8.9 Japan Antacid power according to pharmacopoeia 278ml Phthalate adsorption capacity (0.05N phthalate DOP solution, 100
℃, 1 hour treatment) 4.8meq/g Composition formula Mg _5.85 Al ₂ (OH) ₁₃ (CO ₃ ) _2.35・4.4H ₂ O The X-ray diffraction pattern of the obtained product was as shown in Figure 2. .

Example 4 Basic magnesium carbonate powder (OH ^- /CO ₃ ^2- =
0.5 (mole ratio), MgO content 42%) 50g was stirred into sewage.
In addition to 600 ml, a suspension with a pH of 9.2 was prepared. While maintaining this suspension at 70° C., 177 g of a sodium aluminate aqueous solution (Al ₂ O ₃ content 10%, PH 14 or higher) was added little by little, and the mixture was reacted at the same temperature for 2 hours with stirring. The final pH of the reaction solution was 10.2. After the reaction is complete, the precipitate is collected by filtration, washed with water, dehydrated, dried at 80°C, and crushed to yield 70g of product.
I got it. The analysis results and various physical properties of the product were as shown below.

MgO 29.2% Analysis value Al ₂ O ₃ 24.5% CO ₂ 8.9% Na 0.01% Loss on drying (105℃, 3 hours) 2.0% Loss on ignition (900℃, 3 hours) 45.7% PH of 4% suspension 9.1 Japan Antacid power according to pharmacopoeia 276ml Phthalate adsorption capacity (0.05N phthalate DOP solution, 100
℃, 1 hour treatment) 4.3meq/g Composition formula Mg ₃ Al ₂ (OH) _10.3 (CO ₃ ) _0.85・2.9H ₂ O The X-ray diffraction pattern of the obtained product was as shown in Figure 3. .

Example 5 Basic magnesium carbonate paste (OH ^- /CO ₃ ^2- = 0.667 (molar ratio), MgO content
9.38%, water content 78.98%) Stir 300g of sewage 1
was added to make a suspension with a pH of 10.2, and while heating and maintaining this at 85℃, a sodium aluminate aqueous solution (Al ₂ O ₃
After gradually adding 44.6 g (content 20%, pH 14 or above) of the solution, the reaction was continued at the same temperature for 1 hour with stirring.
The final pH of the reaction solution was 9.1. After the reaction, the precipitate was filtered, washed with water, dehydrated, and dried at 80°C.
After crushing, 69 g of product was obtained. The analysis results and various physical properties of the product were as follows.

MgO 37.9% Analysis value Al ₂ O ₃ 11.9% CO ₂ 15.4% Na 0.08% Loss on drying (105℃, 3 hours) 6.8% Loss on ignition (900℃, 3 hours) 50.1% PH of 4% suspension 9.42 Japan Antacid power according to pharmacopeia 268ml Phthalate adsorption capacity (0.05N phthalate DOP solution, 100
℃, 1 hour treatment) 4.8meq/g Composition formula Mg _8.06 Al ₂ (OH) _16.12 (CO ₃ ) ₃・5.21H ₂ O The X-ray analysis diagram of the obtained product was as shown in Figure 4. .

[Brief explanation of drawings]

1 to 4 show X-ray diffraction patterns of basic carbonates obtained by the method of the present invention.

Claims (1)

[Claims] 1. General formula Mg _x Al _y (OH) characterized by reacting basic magnesium carbonate powder or paste with an alkali aluminate at a temperature of 20 to 100°C while stirring in an aqueous medium. _2x+3y-2z (CO ₃ ) _z・nH ₂ O [However, x and y are positive numbers satisfying 1.5≦x/y≦4.1, z is a positive number satisfying 0.8≦z≦3.0, n
is a positive number satisfying 2.9≦n≦5.3] A method for producing a magnesium aluminum hydrated basic carbonate.