367 Dense Media Cyclone is chosen for the treatment of intermediate size fraction, 1+0.25 mm because in Reflux Classifier, the loss of yield to tailings is more due to high NGM at cut density of separation. So, for sharp separation and maximising yield of clean coal, fine DMC is selected inspite of complexity in operating small diameter DMC. The input washability data (50 – 0 mm) feed in the LIMN model is simulated as per the process flowsheet selected. The principal of incremental ash is used modelling of the process flowsheet as well as controller for Reflux Classifier & Column flotation has been applied. 3. RESULTS AND DISCUSSION 3.1 In case of washery grade, W-V coal, as per existing technology (shown in Figure 3) of new Bhojudih washery with top size of 20 mm the balance of product obtained is mentioned in Table 5. Table 5 - Balance of products Table 7 - Balance of products As per the process developed in LIMN model for the same coal by using the washability data and simulating it as per process flow described at 2.1 above, the balance of products obtained in LIMN with top size of raw coal of 10 mm is mentioned in Table 6. Table 6 - Balance of products as per LIMN model 3.2 In case of washery grade, W-VI coal, as per existing technology (shown in Figure 8) of Dahibari washery with top size of 13 mm the balance of product obtained is mentioned in Table Product Yield% Ash % Clean Coal 29.6 18.0 Middlings 45.5 38.6 Rejects 24.9 60.6 Total 100.0 38.0 Product Yield% Ash % Clean Coal 22.1 18.0 Middlings 41.4 39.6 Rejects 36.5 70.5 Total 100.0 46.1 Equipment Clean Coal Middlings Rejects Yield % Ash % Yield% Ash% Yield % Ash% Primary HM Cyclone 21.6 18.6 Secondary HM Cyclone 31.6 37.4 9.5 60.6 Reflux Classifier 7.9 18.1 5.1 46.1 Column Flotation 5.0 15.2 3.6 40.5 Jig 15.7 65.3 Total 34.5 18.0 40.3 38.8 25.2 63.5
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