| 摘要 |
A process for the preparation of fine droplet-reacted sodium aluminosilicates with the smallest particle sizes, containing less than 0.1% by weight of granules exceeding 25 mu m in size, said aluminosilicates being insoluble in water and containing some bound water, of the general formula xNa2O.Al2O3.y SiO2 in which x is a number from 0.2 to 1.5 and y is a number from 1.5 to 10, prepared by reacting aqueous sodium aluminate with aqueous sodium silicate in the presence of an excess of aqueous sodium hydroxide and subsequent filtration, comprising the step of separately passing a solution of sodium aluminate with a composition corresponding to the molar ratios: 1 Al2O3:1 to 10 Na2O:20 to 200 H2O and a solution of sodium silicate with a composition corresponding to the molar ratios: Na2O:SiO2 from 0.1 to 10 and H2O:SiO2 from 5 to 200 to a spray head, spraying the two solutions into intimate contact, at a ratio by weight corresponding the desired total composition within the molar ratios of: 1.5 to 15 Na2O:1 Al2O3:1 to 15 SiO2:50 to 400 H2O at a temperature of between 0 DEG and 103 DEG C., employing a spray system with at least one spray head with at least two liquid channels, each terminating in a jet spray nozzle, one for each solution, in such a manner that the two solutions meet only after leaving the spray head at a velocity sufficient to form a fine mist of droplets, whereby the two reactants undergo reaction while still in the fine mist of droplets stage, with the formation of an X-ray-amorphous sodium aluminosilicate gel, allowing the droplets to settle and recovering an aqueous suspension of said X-ray-amorphous sodium aluminosilicate in a form adapted for crystallization.
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