Mechanism and performance of a dry particle separator using an elastic drum

• We develop a dry separation tool for low-grade middling ores.
• A novel rotating drum separator covered with an elastic material was designed.
• Ores are separated by the differences in the physical properties.
• It was useful for sorting relatively high calorie coal ores from abandoned wastes.

In order to develop a dry separation tool for low-grade middling ores with high economic feasibility, a novel rotating drum separator covered with an elastic material was designed. The operational principle was based on the simple notion that the differences in the physical properties of ores, such as their shape and chemical composition, should result in different rebounding distances. When ores slide down the drum and rebound from the drum surface, the friction coefficient and repulsion coefficient of the ores affect their collisions with the drum surface, and thus determine their rebounding distances. The basic performance of the elastic drum separator was examined for selected sample ores, including coal, shale, talc, and dolomite. The calculated and experimentally determined rebounding distances were found to be in good agreement for all of the ores. Tests on a 1:1 talc/dolomite mixture showed good performance for the separation of talc from dolomite. It was also found that the shape anisotropy of the ores played an important factor in determining the rebounding distance. The separation of low-grade coal middling dumped at a mine confirmed the performance of the elastic drum. A total of 46.5 wt.% of coal ore with a calorie content of 4991 cal/g was recovered from 45 to 65 mm sized coal ores with an average calorie content of 3576 cal/g. In addition, 35.4 wt.% of coal ore with a calorie content of 3105 cal/g was recovered from 25 to 45 mm-sized ore that had an average calorie content of 1554 cal/g. It was thus verified that the drum separator was useful for sorting relatively high calorie coal ores from abandoned coal wastes.