Understanding the relationship between slag crystallization behaviour and electrical conductivity under isothermal conditions for online slag solidification monitoring in slag recycling.

The slag valorisation is of significant importance in alleviating the problems of environmental impact and resource shortage. Since the slag's electrical conductivity is sensitive to a minor change in its microstructure, conductivity measurements provide a promising method to monitor online slag solidification during hot stage processing. In this work, solidification of a synthetic 34 wt% CaO–19 wt% Al 2 O 3 –39 wt% SiO 2 –8 wt% MgO (CASM) slag was studied in situ using confocal scanning laser microscopy (CSLM), while simultaneously measuring the slag's electrical conductivity with impedance spectroscopy. After the measurement, the microstructure of the quenched slag samples was analysed using scanning electron microscopy (SEM). A quantitative relationship was established between the slag's electrical conductivity and its liquid fraction under isothermal conditions. This relationship can be used for the development of online monitoring systems for the precise control of slag crystallization, to obtain suitable mineralogy for high added value applications. [Display omitted] [ABSTRACT FROM AUTHOR]