Influence of Oxide Nanoparticles of Fe, Al and Si on the Sintered Magnesia for the Production of Refractory Material to Be Used in Secondary Ladle Metallurgy

Abstract

Iron oxide (Fe 2 O 3 , 20-40 nm), aluminum oxide (Al 2 O 3 , 50 nm) and silicon oxide (SiO 2 , 20-60 nm) nanoparticles were mixed in different concentrations (1 to 5 wt %) in a magnesium oxide matrix to develop new refractory matrixes as candidates in the lining of secondary ladle metallurgy. To avoid agglomeration of nanoparticles in the magnesium oxide (MgO) matrix, it was carried out a dispersion method of nanoparticles with different dispersants. After that, the powder mixture was sintered at a temperature of 1300 and 1500 °C for 4 hours. The refractory samples obtained were studied using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectrometer (SEM-with EDX) and also measured their density and porosity. The results showed that the samples sintered at 1500 °C with 5 wt % of Fe 2 O 3 reached the highest density and presented the MgFe 2 O 4 spinel-type phase. With the addition of Al 2 O 3 -nanoparticles in the MgO matrix, there were the formation of MgAl 2 O 4 spinel phase and in the case of SiO 2 -nanoparticles addition it was observed the formation of Mg 2 SiO 4 forsterite phase. It is well known that with the increase in spinel phase in the matrix, there is a significant help to retain quantities of ions of iron and nickel due to the dissolution of the slag into the refractory material extending their lining life.