Recycling Bottom Ash and Steel Slag Containing CaO into Electrically Insulating and Heat-Dissipating Thermal Interface Materials

Bottom ash (BA) and steel slag (SS) wastes are generated in large quantities and primarily recycled as raw materials for concrete. However, the influx of expansive components can cause pop-outs in concrete and reduce the mechanical properties of concrete, prompting the need for alternative recycling methods. Herein, as a new method of recycling BA and SS, an electrically insulating and thermally conductive thermal interface material (TIM) is proposed by incorporating BA or SS filler into a polymer. CaO, which has historically been an obstacle to efficient recycling BA and SS into concrete, is found to improve the thermal conductivity of TIMs. The resulting TIMs exhibit both effective electrical insulation (<2.99 × 10⁻⁹ S m⁻¹) and thermal dissipation (3.64 W m⁻¹ K⁻¹) properties. The proposed recycling method based on BA and SS can contribute to the development of low-cost, electrically insulating, and heat-dissipating TIMs.