Example 1
In a 2 L stainless steel container, 730 g of aluminum hydroxide powder (commercially available from KANTO CHEMICAL CO., INC., Cica special grade) were added into 1110 mL of 48% sodium hydroxide solution (commercially available from KANTO CHEMICAL CO., INC., Cica special grade), and they were stirred at 124° C. for 1 hour to give a sodium aluminate solution (First Step).
After the sodium aluminate solution was cooled to 80° C., ion exchange water was added into the sodium aluminate solution to achieve a total amount of 1500 mL.
After 96 mL of the sodium aluminate solution were separated into a 1 L stainless steel container, pure water was added into the solution to achieve a total amount of 730 mL (concentration of the sodium aluminate solution: 0.8 mol/L). The solution was stirred with keeping a temperature thereof at 25° C., and the solution was aerated with carbon dioxide in an aeration amount of 0.7 L/min. for 60 minutes to give adjusted aluminum hydroxide slurry (low-crystallinity aluminum compound=pseudo-boehmite) (Second Step).
Separately, 49.5 g of magnesium oxide powder (commercially available from KANTO CHEMICAL CO., INC., special grade) were added to 327 mL of pure water, and they were stirred for 1 hour to give magnesium oxide slurry.
In a 1.5 L stainless steel container, the magnesium oxide slurry and the adjusted aluminum hydroxide slurry were added into 257 mL of pure water, and they were stirred at 55° C. for 90 minutes to cause a first-order reaction. As a result, a reactant containing hydrotalcite nuclear particles was prepared (Third Step).
Then, pure water was added to the reactant to give a solution in a total amount of 1 L. The solution was put into a 2 L autoclave, and a hydrothermal synthesis was performed at 160° C. for 7 hours. As a result, hydrotalcite particles slurry was synthesized (Fourth Step).
To the hydrotalcite particles slurry were added 4.3 g of stearic acid (3 parts by mass with respect to 100 parts by mass of hydrotalcite particles) with keeping a temperature of the hydrotalcite particles slurry at 95° C. to perform a surface treatment on particles (Fifth Step). After the hydrotalcite particles slurry of which particles were surface treated was filtered and washed, a drying treatment was performed at 100° C. to give solid products of hydrotalcite particles. The produced hydrotalcite particles were subjected to an elemental analysis, resulting in that Mg/Al (molar ratio)=2.1.
In accordance with a method of Example 1 described in Japanese Laid-Open Patent Publication No. 2003-048712, hydrotalcite particles were synthesized.
In 150 g/L of NaOH solution in an amount of 3 L were dissolved 90 g of metal aluminum to give a solution. After 399 g of MgO were added to the solution, 174 g of Na2CO3 were added thereto and they were reacted with each other for 6 hours with stirring at 95° C. As a result, hydrotalcite particles slurry was synthesized.
To the hydrotalcite particles slurry were added 30 g of stearic acid (3 parts by mass with respect to 100 parts by mass of hydrotalcite particles) with keeping a temperature of the hydrotalcite particles slurry at 95° C. to perform a surface treatment on particles. After the hydrotalcite particles slurry of which particles were surface treated was cooled, filtered and washed to give solid matters, a drying treatment was performed on the solid matters at 100° C. to give solid products of hydrotalcite particles.
Example 2
In a 2 L stainless steel container, 730 g of aluminum hydroxide powder (commercially available from KANTO CHEMICAL CO., INC., Cica special grade) were added into 1110 mL of 48% sodium hydroxide solution (commercially available from KANTO CHEMICAL CO., INC., Cica special grade), and they were stirred at 124° C. for 1 hour to give a sodium aluminate solution (First Step).
After the sodium aluminate solution was cooled to 80° C., ion exchange water was added into the sodium aluminate solution to achieve a total amount of 1500 mL.
After 96 mL of the sodium aluminate solution were separated into a 1 L stainless steel container, pure water was added into the solution to achieve a total amount of 730 mL (concentration of the sodium aluminate solution: 0.8 mol/L). The solution was stirred with keeping a temperature thereof at 30° C., and the solution was aerated with carbon dioxide in an aeration amount of 0.7 L/min. for 90 minutes to give adjusted aluminum hydroxide slurry (low-crystallinity aluminum compound=pseudo-boehmite) (Second Step).
Separately, 49.5 g of magnesium oxide powder (commercially available from KANTO CHEMICAL CO., INC., special grade) were added to 327 mL of pure water, and they were stirred for 1 hour to give magnesium oxide slurry.
In a 1.5 L stainless steel container, the magnesium oxide slurry and the adjusted aluminum hydroxide slurry were added into 257 mL of pure water, and they were stirred at 55° C. for 90 minutes to cause a first-order reaction. As a result, a reactant containing hydrotalcite nuclear particles was prepared (Third Step).
Then, pure water was added to the reactant to give a solution in a total amount of 1 L. The solution was put into a 2 L autoclave, and a hydrothermal synthesis was performed at 160° C. for 7 hours. As a result, hydrotalcite particles slurry was synthesized (Fourth Step).
To the hydrotalcite particles slurry were added 4.3 g of stearic acid (3 parts by mass with respect to 100 parts by mass of hydrotalcite particles) with keeping a temperature of the hydrotalcite particles slurry at 95° C. to perform a surface treatment on particles (Fifth Step). After the hydrotalcite particles slurry of which particles were surface treated was filtered and washed, a drying treatment was performed at 100° C. to give solid products of hydrotalcite particles.
Solid products of hydrotalcite particles were produced in a same manner as in Comparative Example 1 except that reaction conditions of 95° C. and 6 hours for synthesis of the hydrotalcite particles slurry in Comparative Example 1 were changed to hydrothermal reaction conditions of 170° C. and 6 hours.
Example 3
In a 2 L stainless steel container, 730 g of aluminum hydroxide powder (commercially available from KANTO CHEMICAL CO., INC., Cica special grade) were added into 1110 mL of 48% sodium hydroxide solution (commercially available from KANTO CHEMICAL CO., INC., Cica special grade), and they were stirred at 124° C. for 1 hour to give a sodium aluminate solution (First Step).
After the sodium aluminate solution was cooled to 80° C., ion exchange water was added into the sodium aluminate solution to achieve a total amount of 1500 mL.
After 96 mL of the sodium aluminate solution were separated into a 1 L stainless steel container, pure water was added into the solution to achieve a total amount of 730 mL (concentration of the sodium aluminate solution: 0.8 mol/L). The solution was stirred with keeping a temperature thereof at 60° C., and the solution was aerated with carbon dioxide in an aeration amount of 0.7 L/min. for 60 minutes to give adjusted aluminum hydroxide slurry (low-crystallinity aluminum compound=pseudo-boehmite) (Second Step).
Separately, 49.5 g of magnesium oxide powder (commercially available from KANTO CHEMICAL CO., INC., special grade) were added to 327 mL of pure water, and they were stirred for 1 hour to give magnesium oxide slurry.
In a 1.5 L stainless steel container, the magnesium oxide slurry and the adjusted aluminum hydroxide slurry were added into 257 mL of pure water, and they were stirred at 55° C. for 90 minutes to cause a first-order reaction. As a result, a reactant containing hydrotalcite nuclear particles was prepared (Third Step).
Then, pure water was added to the reactant to give a solution in a total amount of 1 L. The solution was put into a 2 L autoclave, and a hydrothermal synthesis was performed at 160° C. for 7 hours. As a result, hydrotalcite particles slurry was synthesized (Fourth Step).
To the hydrotalcite particles slurry were added 4.3 g of stearic acid (3 parts by mass with respect to 100 parts by mass of hydrotalcite particles) with keeping a temperature of the hydrotalcite particles slurry at 95° C. to perform a surface treatment on particles (Fifth Step). After the hydrotalcite particles slurry of which particles were surface treated was filtered and washed, a drying treatment was performed at 100° C. to give solid products of hydrotalcite particles.
In accordance with a method of Example 1 described in Japanese Laid-Open Patent Publication No. 2013-103854, hydrotalcite particles were synthesized.
Into a 5 L container were added 447.3 g of magnesium hydroxide (d50=4.0 μm) and 299.2 g of aluminum hydroxide (d50=8.0 μm), and water was added thereto to achieve a total amount of 3 L. They were stirred for 10 minutes to prepare slurry. The slurry had physical properties of d50=10 μm and d90=75 μm. Then, the slurry was subjected to wet grinding for 18 minutes (residence time) by using Dinomill MULTILAB (wet grinding apparatus) with controlling a slurry temperature during grinding by using a cooling unit so as not to exceed 40° C. As a result, ground slurry had physical properties of d50=1.0 μm, d90=3.5 μm, and slurry viscosity=5000 cP. Then, sodium hydrogen carbonate was added to 2 L of the ground slurry such that an amount of the sodium hydrogen carbonate was ½ mole with respect to 1 mole of the magnesium hydroxide. Water was added thereto to achieve a total amount of 8 L, and they were stirred for 10 minutes to give slurry. Into an autoclave was put 3 L of the slurry, and a hydrothermal reaction was caused at 170° C. for 2 hours. As a result, hydrotalcite particles slurry was synthesized.
To the hydrotalcite particles slum were added 6.8 g of stearic acid (3 parts by mass with respect to 100 parts by mass of hydrotalcite particles) with keeping a temperature of the hydrotalcite particles slurry at 95° C. to perform a surface treatment on particles. After solids were filtered by filtration, the filtrated cake was washed with 9 L of ion exchange water at 35° C. The filtrated cake was further washed with 100 mL of ion exchange water, and a conductance of water used for washing was measured. As a result, the conductance of this water was 50 μS/sm (25° C.). The water-washed cake was dried at 100° C. for 24 hours and was ground to give solid products of hydrotalcite particles.
Example 5
In a 2 L stainless steel container, 730 g of aluminum hydroxide powder (commercially available from KANTO CHEMICAL CO., INC., Cica special grade) were added into 1110 mL of 48% sodium hydroxide solution (commercially available from KANTO CHEMICAL CO., INC., Cica special grade), and they were stirred at 124° C. for 1 hour to give a sodium aluminate solution (First Step).
After the sodium aluminate solution was cooled to 80° C., ion exchange water was added into the sodium aluminate solution to achieve a total amount of 1500 mL.
After 192 mL of the sodium aluminate solution were separated into a 1 L stainless steel container, pure water was added into the solution to achieve a total amount of 730 mL (concentration of the sodium aluminate solution: 1.6 mol/L). The solution was stirred with keeping a temperature thereof at 30° C., and the solution was aerated with carbon dioxide in an aeration amount of 0.7 L/min. for 90 minutes to give adjusted aluminum hydroxide slurry (low-crystallinity aluminum compound=pseudo-boehmite) (Second Step).
Separately, 49.5 g of magnesium oxide powder (commercially available from KANTO CHEMICAL CO., INC., special grade) were added to 327 mL of pure water, and they were stirred for 1 hour to give magnesium oxide slurry.
In a 1.5 L stainless steel container, the magnesium oxide slurry and the adjusted aluminum hydroxide slurry were added into 257 mL of pure water, and they were stirred at 55° C. for 90 minutes to cause a first-order reaction. As a result, a reactant containing hydrotalcite nuclear particles was prepared (Third Step).
Then, pure water was added to the reactant to give a solution in a total amount of 1 L. The solution was put into a 2 L autoclave, and a hydrothermal synthesis was performed at 160° C. for 7 hours. As a result, hydrotalcite particles slurry was synthesized (Fourth Step).
To the hydrotalcite particles slurry were added 4.3 g of stearic acid (3 parts by mass with respect to 100 parts by mass of hydrotalcite particles) with keeping a temperature of the hydrotalcite particles slurry at 95° C. to perform a surface treatment on particles (Fifth Step). After the hydrotalcite particles slurry of which particles were surface treated was filtered and washed, a drying treatment was performed at 100° C. to give solid products of hydrotalcite particles.
In accordance with a method of Example 1 described in Japanese Laid-Open Patent Publication No. H06-136179, hydrotalcite particles were synthesized.
To 1 L of water were added 39.17 g of sodium hydroxide and 11.16 g of sodium carbonate with stirring, and they were heated to 40° C. Then, to 500 mL of distilled water were added 61.28 g of magnesium chloride (19.7% as MgO), 37.33 g of aluminum chloride (20.5% as Al2O3), and 2.84 g of ammonium chloride (31.5% as NH3) such that a molar ratio of Mg to Al, Mg/Al, was 2.0 and a molar ratio of NH3 to Al, NH3/Al, was 0.35. As a result, an aqueous solution A was prepared. The aqueous solution A was gradually poured into a reaction system of the sodium hydroxide and the sodium carbonate. The reaction system after pouring had pH of 10.2. Moreover, a reaction of the reaction system was caused at 90° C. for about 20 hours with stirring to give hydrotalcite particles slurry.
To the hydrotalcite particles slurry were added 1.1 g of stearic acid, and a surface treatment was performed on particles with stirring to give a reacted suspension. The reacted suspension was subjected to filtration and water washing, and then the reacted suspension was subjected to drying at 70° C. The dried suspension was ground by a compact sample mill to give solid products of hydrotalcite particles.
