| 摘要 |
<p>#CMT# #/CMT# Process for producing encapsulated sodium percarbonate particles, comprises spraying a sodium-sulfate-containing aqueous solution onto sodium percarbonate particles in a fluidized bed and simultaneously evaporating water, where for producing the sodium sulfate-containing aqueous solution, sodium sulfate- and sodium percarbonate-containing dust is used. #CMT#USE : #/CMT# The sodium percarbonate is useful as a bleach-active component in detergents and cleaning agents. #CMT#ADVANTAGE : #/CMT# The sodium percarbonate exhibits good storage stability in detergent- and cleaning agent-preparation. #CMT#INORGANIC CHEMISTRY : #/CMT# Preferred Process: The sodium percarbonate-containing dust is separated: in a washer from a gas stream and the aqueous solution obtained with it is used for producing the sodium sulfate-containing aqueous solution; from the exhaust gas of the fluidized bed, in which sodium percarbonate is produced by progressive granulation of sodium carbonate and hydrogen peroxide; or from a gas stream of a pneumatic extraction of sodium percarbonate particles. The aqueous solution is sprayed on sodium percarbonate particles. Preferred Components: The aqueous solution contains sodium sulfate and sodium carbonate in a weight ratio of 95:5 to 75:25. The aqueous solution contains not more than 25 wt.% of dissolved salts. #CMT#EXAMPLE : #/CMT# Sodium percarbonate particles were used for the production of the encapsulated sodium percarbonate particles, which were produced according to the procedure described in by fluidized bed-progressive granulation of aqueous hydrogen peroxide solution and aqueous soda solution, and exhibited an average particle diameter of 0.7 mm and a fine grain component of less than 0.2 mm of less than 2 wt.%. The coating layer was applied on these particles according to the procedure described in in section [0021] by spraying of a 20 wt.% aqueous solution of the coating material in a fluidized bed at a fluidized bed temperature of 60[deg] C and simultaneous evaporation of water. Overall, 4 wt.% of coating material, calculated without water of crystallization, relative to the total quantity of used sodium percarbonate particles and coating material, was sprayed. Dust (comprising sodium percarbonate (71.2 wt.%), sodium carbonate (5.1 wt.%), sodium bicarbonate (1.3 wt.%), sodium sulfate (21.8 wt.%), magnesium sulfate (0.3 wt.%) and water glass, calculated as silicon dioxide (0.2 wt.%)) used for the production of the coating material solution was separated from the exhaust air of a manufacturing-plant for the envelopment of sodium percarbonate particles with sodium sulfate in a fluidized bed.</p> |
