| 摘要 |
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 T<SUB>G </SUB>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 T<SUB>U </SUB>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 T<SUB>NT </SUB>of greater than T<SUB>G</SUB>, or b) the fluidized-bed granulation is carried out in at least two steps at T<SUB>G1</SUB>, T<SUB>G2 </SUB>. . . T<SUB>Gn</SUB>, T<SUB>G2 </SUB>or T<SUB>Gn </SUB>being higher than T<SUB>G</SUB>1, and drying being unnecessary if 2/3 of the granulate have been formed at T<SUB>G</SUB>1, or c) drying takes place not after the granulation but after the coating, at T<SUB>UNT</SUB>, T<SUB>UNT </SUB>being at least 20° C. higher than T<SUB>G</SUB>. |
