An examination of interference in waste solidification through measurement of heat signature

The hydration of cementing materials is accompanied by heat evolution which is closely related to their structure development. The presence of wastes usually interferes with the hydration of cementing materials. This study examined their interference in waste stabilization/solidification processes through the measurement of adiabatic heat evolution using a computerized Quadrel™ system. Two cementitious materials, an alkali-activated blast furnace slag binder and an ASTM Type I portland cement were used to solidify an electric arc furnace (EAF) dust, which has high concentrations of B, Cr, Hg, Pb, Ni and Zn. The EAF dust contents were 0, 30 and 60% by mass. Different mixing conditions were also examined. The interference of EAF dust with the hydration of cementing materials was described using several parameters derived from the heat evolution curves: equivalent initial time of setting (equivalent time at 20°C); total heat evolution at initial time of setting; equivalent final time of setting, total heat evolution at final time of setting and total heat evolution at equivalent time of 28 and 90 days. Experimental results indicated that the Quarel™ system was a useful tool to examine the interference in waste stabilization/solidification and to assist with the selection of cementing materials.