A solid-solid extraction

When a vessel containing two equal-sized particle species is subjected to vibration with an acceleration significantly greater than Ig, the particle bed sometimes separates into two clear-cut layers, the bottom layer consisting only of the lighter particles. This paper shows that the above inverse density segregation can be used to perform a solid-solid extraction. A mixture of equal-sized glass and steel beads (1290 mu m in mean diameter) did not separate into two layers under vibration. However, when equal-sized lead beads were added to the mixture and the three-component mixture was subjected to vibration the bed separated into two clear-cut layers, the top layer being the mixture of the three components, the bottom layer consisting only of glass beads. The scale effect and the underlying mechanisms of this solid-solid extraction are discussed. (C) 2000 Elsevier Science S.A. All rights reserved.