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Iron Ore Pelletizing Grate-Kiln System Brochure

Iron Ore Pelletizing Grate-Kiln System Brochure
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Iron Ore Pelletizing Grate-Kiln System Brochure - 1

Iron ore pelletizing Grate-KilnTM system

Iron Ore Pelletizing Grate-Kiln System Brochure - 2

Plant overview Grate-KilnTM iron ore pelletizing system The first Grate-KilnTM system pellet plant was installed in 1960. The plant took iron ore concentrate and produced superior iron ore pellets (which are spheres of high iron content and uniform quality) for blast furnace and direct reduced iron feed. Since then, Grate-Kiln systems have been used for over 50 plants, on both magnetite and hematite ores, with an installed capacity of over 115 million tpy. Downdraft drying Downdraft drying Green balls Tempered preheat Preheat zone Zone 1 Zone 2 Rotary kiln Travelling grate Annular cooler...

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Iron Ore Pelletizing Grate-Kiln System Brochure - 3

Process flexibility Pelletization process There are two main processes for producing iron ore pellets: The Grate-Kiln system and the straight grate system. In the straight grate system, a continuous parade of grate cars moves at the same speed though the drying, induration and cooling zones. Any change in one section effects the residence time in another. Pelletization is comprised of two main stages: (1) agglomeration and (2) induration. During agglomeration, finely ground particulates (usually 80% passing 44 micron) of ore concentrate (with a moisture content of approximately 9%) are...

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Iron Ore Pelletizing Grate-Kiln System Brochure - 4

Energy efficiency The Grate-Kiln® induration machine is composed of three separate process pieces of equipment. The traveling grate is used primarily to dry and preheat green balls for feeding into the rotary kiln, where they are indurated. Once the green balls are made they are spread out evenly across the grate. The traveling grate provides the means for heat transfer with high, medium and low temperature gases. It utilizes the heat coming from the kiln and cooler to perform this heat recovery. These gases transfer heat by convection so gas to solids contact is required for effective...

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Iron Ore Pelletizing Grate-Kiln System Brochure - 5

Traveling grate CFD Model Baffle walls Preheat zone Common windbox, sloped floor Feautures and benefits Pellet quality Ported kiln operation Predictive control systems Because the induration of the pellets occur in the rotary kiln, the pellets produced in a Grate-Kiln system are consistently of higher quality than those produced in a straight grate. The rotary kiln provides constant mixing of the pellets, bringing all the pellets to the same temperature. In a straight grate, the pellets at the top of the bed are “over cooked” and those at the bottom are “under cooked”. Higher quality means...

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Iron Ore Pelletizing Grate-Kiln System Brochure - 6

Kiln drive components Equipment description Grate The traveling grate is a conveyor that transports balled iron ore concentrate through cross-flow processing zones. The conveying element is a continuous loop assembly of slotted ferrous stainless steel grate plates, chain castings, and side plates to carry a bed of agglomerates. The upper, active, carrying portion of the conveying element is supported level and flat over a head shaft, intermediate upper supporting shaft/roller assemblies and a tail shaft. The grate is driven by a bull gear drive assembly and a variable frequency drive and...

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Iron Ore Pelletizing Grate-Kiln System Brochure - 7

Kiln The kiln is a refractory lined cylinder rotating about its axis. The kiln slopes slightly downward from feed to discharge end. The slope and rotation of the kiln move the material through it. Kiln speed is variable to vary pellet retention time. The kiln is a single chamber with an open feed end connected by housing to the grates preheat furnace Through this connection is the inflow of material to the kiln and outflow of kiln gas to the preheat furnace. The kiln’s discharge end is open and connected to the cooler by a firing hood. Through the firing hood, pellets flow from the kiln to...

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Iron Ore Pelletizing Grate-Kiln System Brochure - 8

• Metso Minerals Industries Inc. 350 Railroad Street, Danville, PA 17821-2046, USA, Phone: +1 570 275 3050, Fax: +1 570 275 6789 • Metso Minerals Industries, Inc. 2715 Pleasent Valley Road, York, PA 17402, USA, Phone: +1 717 843 8671 • etso Minerals (South Africa) (Pty) Ltd. M Private Bag X2006, Isando, Johannesburg,1600, South Africa, Phone: +27 11 961 4000, Fax: +27 11 397 2050 • Metso Minerals (Australia) Ltd. Level 2, 1110 Hay Street, West Perth, WA 6005, Australia, Phone: +61 8 9420 5555, Fax: +61 8 9320 2500 • Metso Minerals (India) Pvt Ltd 1th floor, DLF Building No. 10, Tower A, DLF...

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