203 g of crystalline magnesium chloride such as is used as a food additive,
containing 46% MgCl2, is dissolved in 600 ml of water, to which 96 g of
caustic soda dissolved in 250 ml of water is added with stirring and a solution
comprising 50 ml of water with 207 g of sodium silicate (Na2O, 9%, SiO2,
29%) is further added and is then vigorously stirred to produce basic sodium
magnesium silicate (which is designated as Slurry A).
Secondly 593 g of aluminum sulfate containing 17.2% Al2O3, dissolved in
1,700 ml of water is gently added with stirring to 216 g of caustic soda
dissolved in 600 ml of water, to which 50 ml of water added to 207 g of
sodium silicate (Na2O 9%, SiO2, 29%) is slowly added and is then vigorously
stirred to produce tetrabasic dialuminum silicate (which is designated as
Slurry B). Slurry A and Slurry B are mixed up vigorously with stirring for 3
hours at room temperature. The thus obtained white gel-like precipitate is
washed by decantation to remove free alkali, sodium sulfate, sodium chloride,
etc. produced as reaction by-products. The residue is filtered and dried at
105°-110°C and 340 g of white powder of fine particle size is obtained as the
final product. The molar ratio of MgO to Al2O3, to SiO2, in this product is
approximately 1: 1: 2.
203 g of crystalline magnesium chloride such as is used as a food additive,
containing 46% MgCl2, and 593 g of aluminum sulfate containing 17.2%
Al2O3, are dissolved in 2,300 ml of water, to which a solution comprising 272
g of caustic soda with 800 ml of water, is slowly added with stirring.
Thereafter, a solution comprising 414 g of sodium silicate (Na2O, 9%, SiO2,
29%) with 100 ml of water is added, the mixture is heated and is stirred for
five hours, while keeping the temperature at 60°C. When the reaction mixture
becomes neutral it is allowed to cool and to stand, the supernatant fluid is
withdrawn and the white gel-like precipitate is washed by decantation to
remove the impurities and dried at 105°-110°C and 350 g of white powder of
fine particle size is obtained as the final product (almasilate).
