In coal preparation plants, fines generated (<0.5mm particles) accounts 20 percent-25 percent of ROM. Fine coal cleaning process is getting more attention by process engineers because of the increase in amounts to be handled as well as their difficult washability characteristics. Froth flotation process is being practiced extensively in Indian coal washeries for washing. Generally plants get run-of-mine coal from different sources having different nature and degree of oxidation levels. Characterization of the coal fines reveals that finest fractions contain highest amount of ash forming minerals. Due to entrainment of these ash-forming minerals in froth flotation, fine coal circuits fails to deliver consistent product quality and yield levels. Physical separation can address all these problems with minimum operational costs. Though hydrocyclones and water-only cyclones are identified as economic and efficient units for fine coal cleaning, but has received minimum attention by the Indian coal industry. By analyzing the characteristics of coal fines, cyclones can be effectively employed for washing coal fines. By implementing cyclone technology for fine coal cleaning, operational costs can be reduced drastically. Cyclones can also be employed before or after a floatation circuit with significant benefits.
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