Comparison of conventional crushing and high-voltage pulsed power technology as techniques for disaggregating different types of spent magnesia-carbon refractory bricks during recycling

Abstract

Three different types of spent magnesia-carbon (MgO–C) bricks were chosen to evaluate the liberation of magnesia particles through high-voltage pulsed power technology (HVPPT) and conventional comminution (jaw and cone crushing). The primary objective was to determine how the different types of MgO–C bricks comminute and whether magnesia particles could be restored to their original raw material particle size distribution (PSD).Analytical results revealed that the bricks contained varying amounts of graphite and resin binder, indicating differences in their compositions and therefore comminution properties. The HVPP technique demonstrated its ability to liberate magnesia particles within the +1700 μm fraction, whereas conventional crushing predominantly formed composite particles (containing MgO and carbon) within this size range, with over 63% particles falling in this category. This finding suggests that MgO particles were not adequately liberated during the conventional crushing process, indicating the need for an additional comminution step to achieve the desired liberation.