Ice sublimation from frozen salt solutions

Abstract

The sublimation method of drying is finding ever wider application in scientific and technical fields. For example, one of the newest fields employing this method is cryochemical synthesis of inorganic materials, with sublimation dehydration as the basis of the process. Sublimation of ice from rapidly frozen salt solutions produces powders with a component distribution close to that existing in the solution. We will consider the problem of ice sublimation from salt solutions frozen in the form of a plate, cylinder, and sphere in a flow of noncondensing gas at a pressure of 0.01 ≤ P ≤ 1.02 bars. The noncondensing gas contains vapors of the subliming material at a partial pressure of pf. Comparison of theoretical and experimental data reveals completely satisfactory agreement. The mass output coefficient, which is usually determined experimentally for mass-exchange processes with phase transitions, can be found in a manner analogous to the heat-liberation coefficient for a volume content of noncondensing gas between 25 and 100%.