Chemical and microstructural characterization of blast furnace slag

Abstract

Blast furnace slag is a byproduct of iron and steel production, whose physicochemical characteristics are influenced by the type of production process applied. Furthermore, its chemical composition depends on the raw materials used, the most common ones being mineral iron, coke and limestone. Blast slag can solidify into four different forms: crystallized, granulated, pelletized and expanded. Crystallized slag obtained from blast furnace production was studied in this work. This slag has high porosity and reduced mechanical strength when compared to other slags. The samples were submitted to thermal treatment at 860, 960 and 1060^°C for one hour. These samples were characterized by X-ray diffraction (XRD), infrared spectrometry (FTIR), X-ray Fluorescence (XRF) and scanning electronic microscopic/EDS. Based on the results, it was possible to predict the behavior of crystallization of the slag at different calcination temperatures and identify the present phases at each temperature range. This work aimed to characterize the blast furnace slag residue from steel production at the Acepar Company, in order to propose a higher added value application related to advanced ceramics production.