Effects of MgO additive on metallurgical properties of fluxed-pellet

Abstract

As a main charging burden of blast furnace (BF) ironmaking process, pellets play an important role in ironmaking process. However, compared with sinters, there are some inevitable disadvantages for traditional acid pellets, e.g., reduction swell, low melting temperature. Therefore, the fluxed-pellets have been applied in BF, especially MgO-fluxed pellets. In the present study, the effects of category and content of MgO bearing additive on the compressive strength (CS), reduction swelling index (RSI), reduction disintegration index (RDI) and melting-dripping properties of the pellets were investigated. Minerals composition, pore distribution and microstructure of MgO-flux pellets were studied by X-ray powder diffraction (XRD), mercury intrusion method and scanning electron microscopy (SEM), respectively. The results show that the light burned magnesite (LBM) is more suitable MgO bearing additive for fluxed-pellets. With increasing LBM content from 0 to 2.0%, the CS decreases from 3066 to 2689 N, RSI decreases from 16.43% to 9.97% and RDI decreases from 19.2% to 12.99%. The most appropriate MgO bearing additive content in the fluxed- pellets is 2.0% according to principal component analysis (PCA).

Keywords

pellets / MgO bearing additive / porosity / swelling / ironmaking / principal component analysis

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