Influence of Oxide Nanoparticles of Fe, Al and Si on the Sintered Magnesia for the Production of Refractory Material to
- PDF / 300,268 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 21 Downloads / 149 Views
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 Cristian Gómez1, Tushar.K.Das, Sadasivan Shaji, Edén A. Rodríguez, Ana M. Guzmán, Alan Castillo, Laura García. 1 Programa Doctoral en Ingeniería de Materiales, Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Universidad S/N, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, México, C.P. 66451 ABSTRACT Iron oxide (Fe2O3, 20-40 nm), aluminum oxide (Al2O3, 50 nm) and silicon oxide (SiO2, 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 Fe2O3 reached the highest density and presented the MgFe2O4 spinel-type phase. With the addition of Al2O3-nanoparticles in the MgO matrix, there were the formation of MgAl2O4 spinel phase and in the case of SiO2-nanoparticles addition it was observed the formation of Mg2SiO4 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. INTRODUCTION Historically, MgO-Cr2O3 refractories have been used in secondary ladle metallurgy, however the use of this kind of refractory represents a real problem, which is harmful for human body [1-3]. MgAl2O4 and MgFe2O4 spinels have been added to MgO matrix resulting in refractories with good physical and chemical properties such as good chemical resistance against slag and suitable mechanical properties [4]. The use of ZrO2 as second phase has resulted in an attractive refractory material but it is an expensive one. The addition of Fe2O3 in an MgO matrix with a particle size greater than 45 μm, develops a refractory matrix with melting points of 1713 °C obtaining favorable results in mechanical properties, since this fact leads to a decrease in porosity [5-6]. By other hand, it is important while considering the material purity, since impurities (i.e. CaO, SiO2) greater than 2 wt% in MgO based refractories lead to the loss of refractoriness forming low melting point phases such as calcium aluminates, calcium ferrites or calcium-iron aluminates [7]. Nanotechnology seems to be one of the main routes for improving refractory materials used in this industry. It is well known that the use of
Data Loading...
