Influence of the cooling process on the physicochemical properties of ladle furnace slag, used in the replacement of Portland cement

Abstract

ABSTRACT Ladle furnace slag is a waste composed essentially of quicklime or hydrated lime, whose contents depend on the raw material and the cooling process that led to the slag batch. With this chemical composition, it is used by civil construction as a hydraulic binder in cement matrices. The chemical compounds mentioned are also present in Portland cement, which are part of the chemical reactions of hydration and hardening. However, the quality of LFS batches calls for attention to volume expansion caused by chemical compounds whose presence and content can be controlled by the cooling method adopted in the production. Considering the use of this material as a partial replacement for Portland cement, the objective of this study was the physicochemical characterization of LFS samples to evaluate the influence of the cooling method on its potential as a complementary binder in cementitious matrices. In this sense, 3 samples from different batches were analyzed and the effects of each cooling process. The results include analysis of specific mass, laser diffraction for particle size analysis, X-ray fluorescence and X-Ray Diffraction tests. It was verified that the sample obtained by slow cooling is the most suitable as binder, as it features less possibility of expansive chemical reactions and presents greater fineness.