Process for the preparation of coated granular sodium percarbonate, and product obtainable by the process

US7241433B2 · kind B2 · utility

Assignee

• Degussa AG · DE

Inventors

• Harald Jakob · Hasselroth, DE
• Waldemar Hessberger · Alzenau, DE
• Juergen Lattich · Nidderau, DE
• Ralph Overdick · Hofheim, DE

Key dates

• Filing date: Aug 20, 2002
• Grant date: Jul 10, 2007
• Expiry date: Oct 11, 2023

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01B15/106
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The invention relates to a process for the preparation of coated granular sodium percarbonate having a low TAM value. The preparation is carried out by fluidized-bed spray granulation at a temperature TG in the range from 45 to 75° C., and the coating is effected by the spray application of an aqueous solution containing at least one coating component in a fluidized bed at a temperature TU in the range from 35 to 100° C. According to the invention, a) after the fluidized-bed spray granulation but before the coating, drying is carried out at TNT of greater than TG, or b) the fluidized-bed granulation is carried out in at least two steps at TG1, TG2 . . . TGn, TG2 or TGn being higher than TG1, and drying being unnecessary if ⅔ of the granulate have been formed at TG1, or c) drying takes place not after the granulation but after the coating, at TUNT, TUNT being at least 20° C. higher than TG.