CHEMICAL AND STRUCTURAL CHARACTERIZATION OF SLAG COMPOUNDS FORMED IN THE MELTING PROCESSES TO PRODUCE SPHEROIDAL GRAPHITE CAST IRONS

摘要

The aim of this research is to investigate the composition and phases present in the slags formed during the production of spheroidal graphite (SG) cast irons. This paper contains the results of the first part of such investigation which is focused on those slags generated in the induction furnace, i.e., solid slags formed on the melt surface and slags adhered to quartzite refractory lining. A group of slag samples of each type were obtained from melts prepared using different metallic charges. These samples were then characterized in order to determine their chemical and structural composition and to evaluate the influence of the raw materials used during the melting process on the amount of slag formed in each case. Three different techniques were used for analyzing the slag samples: X-ray fluorescence, X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy (EDS) microanalysis. Important differences have been detected among samples studied in this work that have revealed the detrimental role of aluminum on refractory linings. The knowledge has been successfully used to minimize the problems caused by adhesion of slags to refractory linings.