Metal hydrodynamic cavitation

Moser et al. [37] applied hydrodynamic cavitation generated by a microfluidiser for the synthesis of large variety of catalysts in the form of nanosized grains. The grains agglomerated into particles of 100 nm to few microns. This process was found to provide high purity catalysts containing several metal ions than classical synthetic methods. 

A continuous process based on hydrodynamic cavitation can be employed to prepare a wide variety of metal oxides in grain sizes of 1 -10 nm, such as iron oxide, bismuth molybdate, perovskites, platinum-loaded zeolite, and other ceramics and superconductors [170]. The method uses a microfluidiser for mechanically generating hydrodynamic cavitation and the internal pressure of the liquid media is elevated from ambient pressure to between 1000 to 25 000 psi. 

Fig. 3. Schematic of a typical hydrodynamic cavitation synthesis of metal oxides starting with a metal salt solution, which is precipitated and processed in a cavitating stream of bubbles.

D. Synthesis of Metal Oxide Catalysts and Supported Metals BY Hydrodynamic Cavitation... 

Cavitation can be minimized by a proper design to minimize hydrodynamic pressure differences and specifying a smooth finish on all critical metal surfaces. One can use higher pressure or lower temperature to reduce the formation of the damaging steam bubbles causing cavitation. Proper operation of pumps and equipment is necessary, for example, a pump should not be operated on plugged or impaired flow lines.84... 

Cavitation occurs when the hydrodynamic pressure exceeds the vapour pressure of a moving liquid. Gas bubbles form within the liquid, which thus becomes a two-phase system. These bubbles will be crushed against the metal surface at high speed, an attack... 

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