Role of magnesium chloride in the performance and phase composition of lead glass sludge foam.

• Lead glass sludge (LGS) was prepared with no foaming agent addition. • Adding MgCl 2 caused a notable retardation in foaming process at all temperatures. • MgCl 2 enhanced LGS crystallization by the formation of diopside and cristobalite. • A significant decrease in Pb-leaching rate was achieved by adding MgCl 2. In the present work, different MgCl 2 dosages were admixed with lead glass sludge (LGS) to evaluate their effects on the performance of the produced LGS-foam at different elevated temperatures. The results revealed that adding MgCl 2 caused a negative impact on the bloating process, including porosity and volume expansion reduction, as well as bulk density and thermal conductivity increment. This was associated with the high affinity of magnesium for enhancing the crystallization of LGS through the formation of diopside and cristobalite minerals. Moreover, the speed up of softening temperature of LGS using MgCl 2 makes LGS completely softened before full dissociation of CaCO 3 , decreasing gas entrapping inside the softened LGS. Nevertheless, the use of MgCl 2 decreased the free Pb inside LGS through thermal/chlorination process. [ABSTRACT FROM AUTHOR]