Quantitative study and variation of free lime content in BOF slag using Leduc method

Abstract

The main issue hindering the widespread use of steel slag as a construction material is its volumetric instability. This instability is mainly caused by the hydration of free lime and magnesium oxide. Particularly, free lime is the primary contributor to the volume instability in converter slags. Therefore, quantifying the lime content in the slag is essential for assessing its stability. The determination of free lime content is challenging due to its various forms and distribution within the slag. This study employs the Leduc method complemented by TGA and XRD to quantify free lime in selected BOF slags and investigates its distribution. Results show varying free lime content in different slags. Analysis of aggregates indicates higher free lime in cores than periphery. For fine materials, free lime content increases with decreasing particle size, with the smallest fraction (0/0.04 mm) providing the most representative value. These findings contribute to understanding BOF slag properties and improving methods for assessing its stability for construction use