Segregation modes, characteristics, and mechanisms of multi-component lignite in a vibrated gas-fluidized bed

Abstract

The segregation modes and characteristics of 1–6 mm multi-component lignite were studied in a micro-porous, vibrated, gas-fluidized bed of Φ110 mm × 400 mm. The effects of particle density and size, vibration frequency and amplitude, and gas velocity on these characteristics were considered. The average size, average density, size deviation coefficient, and density deviation coefficient were used to identify lignite size and density. The separation efficiency was adopted to evaluate the segregation performance, and the segregation mechanisms were explored. The results show that εsize,max of heterogeneous multi-size-component lignite with Ksize = 65% reaches 80% at f = 20 Hz, A = 5 mm, and N = (1,3). εdensity,max of heterogeneous multi-density-component lignite with Kdensity = 25% reaches 50% at f = 15 Hz, A = 5 mm, and N = (1,1.5). The density segregations of 1–3 and 3–6 mm multi-component mixtures are remarkable, εdensity,max = 42% and 31% at f = 14 and 16 Hz, and A = 3 and 5 mm, respectively. The size segregation of 1–6 mm multi-component mixture is prominent and εsize,max = 55% at f = 15 Hz, A = 5 mm. The medium-sized mixture with a narrow size distribution at low frequency is favorable for density segregation, and a mixture with a wider size distribution at high frequency is most favorable for size segregation. Precise control of gas flow and vibration as well as optimal design of the fluidized bed can improve the performance of segregation in the vibrated gas-fluidized bed. Keywords: Dry-beneficiation, Multi-component lignite, Segregation mode, Degree of homogeneity