Study on the Dynamics of Tribocharged Coal and Mineral Particles in Free-Fall Triboelectric Separator

The dynamics of 2.0 similar to 0.8 mm or 0.8 similar to 0.5 mm size fraction of tribocharged organic coal, pyrite, and calcite particles were studied under the electric field using the high-speed dynamic camera combined with high-speed motion analysis system. Motion images of these particles were obtained and used to analyze their dynamic parameters. Organic coal particles tribocharged positively move to the negative plate, while pyrite and calcite particles reach the positive plate under the influence of electric force. These results indicate that the trajectories of all 2.0 similar to 0.8 mm particles are similar to parabolic curves. For 0.8 similar to 0.5 mm particles, the trajectories are approximate straight line, except for the calcite. The vertical velocities of all particles increase with a fluctuant acceleration as a result of gravity and drag force. The horizontal velocities of all particles vary slightly. The dynamics of 0.8 similar to 0.5 mm particles prove that size is very important for the triboelectric separation. The actions of electric force and drag force are increased with the decrease of particle size.