Vacuum disintegration: physical mechanism and technological applications
S.A. Novopashin, V.G. Prikhodko, V.N. Yarygin, I.V. Yarygin
Kutateladze Institute of Thermophysics, Siberian Branch of the Russian Academy of Sciences, Russia, Novosibirsk
Keywords: vacuum disintegration, non-equilibrium phase transition, porous medium, clay rock, thermoelastic stresses
Abstract
This paper systematizes current data on the vacuum disintegration of materials of diverse nature-ranging from gold-bearing clay rocks to biopolymers and pharmaceutical substances. It is demonstrated, both experimentally and theoretically, that these processes are governed by a unified physical principle: the non-equilibrium phase transition of capillary- or chemically bound water during a rapid decrease in ambient pressure. Four dominant disintegration mechanisms are identified (degassing-induced cracking, sublimation fragmentation, thermal-gradient cracking, and capillary cavitation), and order-of-magnitude estimates of the resulting stresses are provided. A dimensionless regime criterion is introduced to determine the disintegration type independently of the specific material. The existence of an optimal initial moisture content is demonstrated (20-25% for clays, 10-15% for starch). Examples of industrial implementation in the pharmaceutical and food industries, as well as in soil vacuum leaching, are presented; prospects for applying the method across various technological chains are discussed.
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