DEM numerical studies on the design and efficiency of the continuous operating triboelectric separator
Triboelectric separation has gained importance as a dry separator for mineral and coal beneficiation. The different grade components of coal powder can be classified, beneficiated, and segregated with the help of the triboelectric separator. A batch-mode triboelectric separator is being used in CSIR-Institute of Minerals & Materials Technology for separating pure coal particles from gangue quartz and kaolinite particles. The sticking of particles on the electrode plates forces the separator to be paused for cleaning the electrode plates. A moving belt over an electrode plate can prevent its direct contact with particles and also carries the particle down towards collection bins. The feasibility study of installing moving belts along with the optimum conditions for design and operating parameters were studied with the help of DEM simulations. The bi-modal frequency distributions of coal and quartz in collection bins ware observed. The rationale for observation of bi-modal distribution is attributed to the varying initial angles and velocities of the particles entering the active electric field region. The non-uniform probabilistic opportunities of the particles to attach with the respective belts resulted in two groups of particles; (a) particles attached to belt followed by their collection in the expected bins (b) particles with initial inclination opposite to the direction of external force and their collection in the bins on the other side. The second group of particles followed trajectories governed by external forces and got collected into the bins on the other side. The phenomena resulted in the bi-modal distribution of mass distribution.
Keywords: Triboelectric separation, Discrete element method, Numerical simulations, Coal