Avaliação da utilização de diferentes materiais para diminuição da tendência de colagem de pelotas durante o processo de redução direta

Abstract

The process for obtaining metallic iron by direct reduction of iron ore is very important for the iron making and its technology has developed significantly in recent decades. The formation of clusters by sticking the pellet during reduction is considered a substantial obstacle to this evolution, which decreases the permeability of gases through the burden,thus affecting the reactor performance. Several studies have addressed the issue and are complementary in describing the sticking phenomenon. This paper evaluated the use of different materials to decrease the tendency of pellets sticking together during reduction. Pellets were submitted to laboratorial tests that consist of spraying them with a suspension of selected materials and water, followed by reducingthem in a direct reduction reactor, according to the 11256 ISO standard. Mostly of the selected materials were MgO sources, as dunite, serpentinite, dolomite, magnesite, talc and olivine. Other ones were limestone, bentonite and itabirite tailing. MgO sources showed better figures, mainly serpentinite and olivine. Dolomite has a goodpotential for replacing limestone.