Particle Chromatographic Separation of Coal Fly Ash

Abstract

Attempts were made to totally separate the 13 types of particles in a coal fly ash. While a considerable separation was obtained, it was far from complete even with optimal operating conditions. The best results were obtained with camphor as the host material in the tilt rotating zone melting technique with a tube rotation rate of 25 rpm and a tube tilt angle of 30° to the horizontal. Additional zone passes improved the separation only slightly. The zone travel rate at which each particle type was trapped, and the length over which each type was trapped, both increased as the tube rotation rate was increased and as the tilt angle was decreased. If a bubble contacted the interface during horizontal operation, the trapping occurred at significantly lower freezing rates and the separation was considerably worse. The smaller particles were trapped at lower freezing rates than larger particles. Naphthalene and biphenyl proved to be poor hosts because of extensive bubble formation at the interface during zoning. Particles were trapped at impractically low freezing rates with Salol.