High Power Ultrasonics in Pyrometallurgy: Current Status and Recent Development

Abstract

In recent years, a large number of studies have been published on the use of high intensity ultrasonics in various high temperature technologies. This paper provides an overview of the recent achievements and ongoing works on the application of high intensity sound waves to pyrometallurgy and its related areas. The published results have strongly suggested that ultrasonics has the potential to play a more significant role in such areas as the dedusting of high-temperature exhaust gas, improvement of fuel-combustion efficiency, control of air-pollutant emissions, improvement of the quality of ingots, production of metal powders and ascast composite materials.At higher temperatures, special attractiveness of sound waves is associated with the fact that the waves can propagate through gas, liquids, and solids, and thus supply the acoustic energy from a cooled sonic generator to materials being processed under high temperature conditions. This provides a unique tool, for example, for controlling the rates of interfacial phenomena that is unachievable by any other methods under high temperatures.Industrial competitiveness of the ultrasonic-based technologies is reinforced by the relatively low cost of power-generating equipment and ultrasonic transducers. However, further research efforts are called for to develop new heat-resistant waveguide materials and to integrate the ultrasonic installations with existing industrial facilities in high temperature technologies.KEY WORDS: pyrometallurgy; high temperature; sonoprocessing; high power ultrasonics; non-linear phenomena; air pollutants; continuous casting; melt atomization; cast composites.applications have been summarized in a book by one of the authors of the present review. 4)The following two circumstances make ultrasonics especially applicable to high-temperature technologies: 1) There is a severely limited choice of techniques available for supplying energy under conditions involving higher temperatures. Among these techniques, sonic/ ultrasonic treatment or sonoprocessing should be competitive as regards both technique and cost, because it provides an effective transmission of acoustic energy from the ultrasonic generators to the materials being processed at a relatively low cost for ultrasonic equipment. 2) It is well-known that interfacial phenomena play an important role in governing many high-temperature processes. Examples are mass and heat transfer, crystal growth during the solidification of liquid metals, wetting, and emulsification. Sonic and ultrasonic waves propagate through homogeneous elastic mediums without significant losses. However, when the waves are incident upon an interface, the scattering or reflecting or of the waves from the interface is responsible for a number of nonlinear phenomena that occur at the interfaces. These provide a unique tool for controlling the rates of interfacial phenomena. Such a tool is unachievable by any other methods. Along with improvements in the earlier methods of sonoprocessing, a number of new ultrasonic appl...

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The Sound Velocity in an Alloy Steel at High-Temperature Conditions

“…The use of such technologies as high-temperature piezoelectric ceramics allows the power head to work more efficiently compared to magnetostrictive transducers for steel sonication used previously under laboratory conditions [1][2][3][4][5]. Research concerning the shaping of cast steel structures using sound waves has been carried out at the Department of Metallurgy of the Silesian University of Technology.…”

Application of Airborne Sound Waves to Mass Transfer Enhancement

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