Multotec Gravity Division reported its new SX10 low-density spiral is capable of a reduced cut point of 1.55 g/cm3, which offers advantages over cut points between 1.6 and 1.8 g/cm3. One is cleaner coal with less waste, both achieved in a single stage. Another is reduced capital costs because no further spiral stages are required, the company reported. The solution can reportedly remove gangue from the trough in two off-takes. The first off-take removes ash. That opens the available separation surface of the spiral for off-take two, allowing the remaining material to separate easily. The two off-takes remove most of the gangue, leaving middlings and cleaner coal products to be collected at the dart
splitters. A longer spiral helps the process. It increases the residence time, giving the particles sufficient time to separate, the company reported.
http://www.multotec.com