Effects of MgO Containing Additive on Low-Temperature Metallurgical Properties of Oxidized Pellet

Abstract

As a main charging form of BF (blast furnace), pellets play an important role in blast furnace process. However, comparing with sinters, pellets have many disadvantages, such as reduction swelling, low softening and melting temperature and so on. Therefore, the flux pellets have been applied in blast furnace widely, especially MgO containing pellets. The light burned magnesite is applied as MgO containing additive in pellet production. The characters of light burned magnesite are explored. Meanwhile, the effects of it on low-temperature metallurgical properties are investigated such as low-temperature reduction degradation index (RDI), compressive strength (CS) and the reduction swelling index (RSI). The light burned magnesite calcined at 850 °C manifests better grindability, larger specific surface area, and higher hydration activity. It is found that the addition of light burned magnesite can improve low-temperature metallurgical properties (RDI, RSI) of the pellets. With the increase of light burned magnesite in pellets, the RSI and RDI decrease gradually; when the proportion of light burned magnesite does not exceed 2.0% in pellets, the CS decreases slightly, but it still surpasses 2 689 N, which can still meet the demand of BF.