| 摘要 |
<p>Fine particle coal is beneficiated in specially designed dense medium cyclones (25, 33) to improve particle acceleration and enhance separation efficiency. Raw coal feed (1) is first sized (2) to remove fine coal particles (3). The coarse fraction (4) is then separated into clean coal (9), middlings (10), and refuse (6). Middlings are comminuted (11) for beneficiation with the fine fraction (3). The fine fraction (3) is deslimed in a countercurrent cyclone circuit (21) and then separated as multiple fractions of different size specifications in dense medium cyclones (25, 33). The dense medium contains ultra-fine magnetite particules of a narrow size distribution which aid separation (25, 33) and improve magnetite recovery. Magnetite is recovered from each separated fraction independently, with non-magnetic effluent water (48) from one fraction diluting feed of a smaller-size fraction (24), and improving both overall coal and magnetite recovery. Magnetite recovery is in specially designed recovery units, based on particle size, with final separation in a rougher-cleaner-scavenger circuit (28, 58) of magnetic drum separators incorporating a high strengh rare earth magnet.</p> |
