DRYING OF WET BORAX PENTAHYDRATE BY MICROWAVE BOATING

In this study, drying of borax pentahydrate [Na2B4O7 . 5H(2)O] (BPH) b y microwave energy is investigated. Using 100-700 W and 2450 MHz micro wave energy, 5-10% moisture containing BPH placed on a Teflon-lined be lt is dried at 60-100 degrees C selectively, without any loss of water of crystallization. In this process the microwave oven is first set t o 70 degrees C and then wet BPH which is previously heated to 70 degre es C is placed in it. The sample first heats up to 80-100 degrees C by the effect of microwave energy, and then its temperature sharply drop s, resulting in complete removal of moisture. This process gives way t o no decomposition and disintegration of hydrated crystalline molecule and there are no contaminants involved. Therefore, dry borax pentahyd rate dried this way retains its original purity and physical form. Sin ce there is no need to heat the drying system and the air and to keep the relative humidity of the air constant, microwave drying is more ec onomical than the conventional process. In addition, a sharp decrease of temperature right after complete drying gives way to easy control o f the process by simply regulating the temperature.