A VESSEL FOR LOW-PRESSURE ACID DISSOLUTIONS OF MINERAL AND INORGANIC SAMPLES

Microwave-assisted acid dissolution of minerals and inorganics is rapi d, but difficulties in controlling the temperatures of such systems pr esent potential safety problems. This drawback can be overcome by the use of specifically designed equipment which is, however, expensive. D issolution under conventional heating, although slower, is inherently safer, temperature control being simple and reliable, as well as inexp ensive. For laboratories with high sample loads, the importance of the dissolution time can be reduced significantly simply by heating a lar ge number of samples simultaneously. For such systems, microwave heati ng holds little or no advantage over conventional heating. Presented h ere is a vessel designed specifically for this purpose. It is construc ted of polyvinylidene difluoride, has a volume of 20 mL, and can be us ed up to 120 degrees C at 4 atm. This vessel has two major advantages: the use of conventional heating obviates the need for special (and ge nerally expensive) ancillary equipment and the small size and relative ly low cost facilitate heating large numbers of such vessels simultane ously. These vessels have been in routine use in these laboratories fo r the past 8 years. Forty of them are often heated together in a conve ntional laboratory oven.