Drying of precipitates by the irradiation of ultrashort waves

Abstract

Ultrashort waves have been used for drying in lumber and food industries. The authors tried to use of household electronic range as a drying oven in gravimetric analysis as specified below:Instrument: National Electronic Range NE5600 (550W)General method: The specimen is irradiated by the ultrashort waves in the electronic range for 10 to 20 minutes and then the specimen is placed in a desiccator for 20 minutes followed by weighing. The operation is repeated until the weight becomes constant.Results: A weighing bottle, a sintered glass filter and a porcelain crucible could be dried in the electronic range after 3 to 4 times treatments each for 10 minutes, but by conventional heating at 105 to 110°C, several hours were necessary.Copper sulfate crystals dried in the electronic range was found to have lost four moles of water of crystallization.Calcium oxalate precipitate could be analyzed gravimetrically by drying in the electronic range and the composition was found to be CaC2O4·H2O.Zinc and lead 8-hydroxyquinolates were dried in the electronic range and the composition of them after drying was found to be Zn (C9H6NO)2·2H2O and Pb-(C9H6NO)2.The merit of the use of an electronic range is that it can dry the specimen within a much shorter time than conventional methods. The results by this method seem to correspond to those obtained by conventional drying at 105 to 110°C, but the reproducibility of results by the present method is better than by the conventional ones.