Agglomeration: Equipment

Equipment
Combustion Technology
Energy Consumption
Process Description

In the pelletizing process, fine ore concentrate is mixed with a binder (bentonite) and formed into green balls in the balling drums. These green balls are then fed into traveling grate kiln furnaces where they are dried and heated and then pass into a rotary kiln for final heating to a point just below fusion (2400°F). The largest furnaces are capable of producing 3.3 million tons of pallets per year.In the sintering process, ore, limestone, and coke fines are mixed and deposited on a traveling grate. Burners ignite the mixture at the feed end of the grate. Air is pulled down through the bed to cause the burning zone to move through the bed until the sintering of the mixture has taken place throughout the entire depth of the bed. The porous, clinker-like sinter is cooled and broken up for use in the blast furnace. The use of sinter reduces coke requirements in the blast furnace, because the limestone is pre-reduced in the sinter bed. Typical daily production from a sinter plant is on the order or 2.3 to 4.4 net tons/sq ft. of grate area.

The Making, Shaping, and Treating of Steel, 10th Edition, Association of Iron and Steel Engineers, 1985.