The traditional use of basic oxygen furnace (BOF) slag as an aggregate
in road construction has been restricted due to the slag's expansive
nature, attributed to the hydration of the calcium and magnesium oxide
s content. Consequently, a significant proportion of the slag is now b
eing stockpiled. In the present work, the thermal behaviours of an ind
ustrial steelmaking BOF slag and of calcium and magnesium oxides, were
examined in order to explore means of thermally stabilizing the slag
and minimizing its susceptibility to hydration. Thermal analysis techn
iques, supplemented by Fourier transform infrared spectroscopy and X-r
ay diffraction, were used to study the materials in dry air, moist air
and CO2. An optimum method for thermally treating the slag is propose
d and the susceptibility of the treated slag to form hydroxides on hyd
ration was found minimal.