A solid-solid extraction

When a vessel containing two equal-sized particle species is subjected to v ibration with an acceleration significantly greater than Ig, the particle b ed sometimes separates into two clear-cut layers, the bottom layer consisti ng only of the lighter particles. This paper shows that the above inverse d ensity segregation can be used to perform a solid-solid extraction. A mixtu re of equal-sized glass and steel beads (1290 mu m in mean diameter) did no t separate into two layers under vibration. However, when equal-sized lead beads were added to the mixture and the three-component mixture was subject ed 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 sol id-solid extraction are discussed. (C) 2000 Elsevier Science S.A. All right s reserved.