nfcl, mangalore dap/npk plant feasibility study - Environmental ...

8ANNEXURE-IVTo improve screen efficiency each screen has a dedicated vibrating feeder toevenly distribute the feed across its entire width.The Oversize Screens will separate from the on-size and fine product, theoversize fraction above 4 mm, which is crushed in four Oversize Mills. Feedingis accomplished by independent chutes from each screen. The suggested milltype is a double rotor chain mill, which provides and efficient crushing withsmall size dispersion on ground product.These mills directly discharge onto the Recycle Conveyor, through oversizedchutes. The product under 4 mm flows to the four single deck Undersizeprocess Screens, which separate the fines below 1 mm, sending them back torecycle.The on-size product from all four screens is collected in the Recycle RegulatorConveyors. These belt conveyors will adjust the required amount of productdesired for production. The extraction rate, controlled by the Recycle RegulatorBelt Weighers, will be fixed from DCS in Control Room and it will regulate beltsspeed and the amount of on size product going to final product treatmentsection. The operator should fix a rate on the weighers to extract from thegranulation loop only the required quantity of product to match the productionrate after passing through Cooler and Polishing Screen. Any excess of on-sizeproduct will not be extracted at that belt speed and will automatically overflowfrom the recycle regulating hoppers the recycle conveyor.The recycle conveyor will receive:Dust from all cyclonesFines from all undersize screensCrushed oversize from millsOverflow from recycle regulator conveyorsFines from polishing screen