| 摘要 |
<p>1,246,915. Dehydrating sodium perborate tetrahydrate. KALI-CHEMIE A.G. 23 Sept., 1969 [5 Oct., 1968], No. 46900/69. Heading C1A. Sodium perborate tetrahydrate is dehydrated in a vibratory drier in several zones in which it is contacted with gases at successively higher temperatures, the temperature in a first zone being at least 80‹ C. and not more than 160‹ C. in a final zone and before leaving the drier, it is cooled with air between 0‹ and 25‹ C. In order to produce the monohydrate, the temperature of the gases introduced rises from 85‹ C. in the first zone to 145‹ C. in the final heating zone, however, if it is only required to remove 0À3 to 0À7 moles water per mol. tetrahydrate, the temperature of the gases rises from 80‹ C. in the first zone to 95‹ C. in the final heating zone. In the examples given, there are four separate heating zones and the cooling zone in the drier; air at the various temperatures is obtained by mixing air at ambient temperature and steam-heated air in various proportions, and moist air and entrained dust is extracted in exhaust pipes. The dust may be recovered in a cyclone.</p> |
