Preparation and performance characterization of steel slag-based thermal storage composites for waste recycling and thermal energy storage

Abstract

ABSTRACT At present, the steel industry produces a large amount of steel slag during the smelting process, which causes serious pollution to the environment and land. Therefore, new technologies must be used to deal with steel slag. In this study, the steel slag powder refined by the wet grinding technology is used as the matrix material, MgO as material additive, and the clay is used as the binder to prepare a new type of composite heat storage material. The results indicate that the mass ratio of wet grinding steel slag powder, MgO powder and clay is 6:3:1, the composite heat storage material can have a strong compressive strength of 70.9 MPa. The thermal conductivity of the heat storage material is 0.98 W/m⋅K and can reach 1.27 J/g⋅K at 720 ℃, which has good thermal conductivity and long service life. When the heat storage material rises to 900 ℃, the heat storage density can reach 905 J/g, with good heat storage performance and thermal cycle stability. The objective is to develop sustainable and low-cost thermal energy storage material for industry waste heat recovery and in renewable energy applications. At the same time, this valuable market for slag in the energy field provide a new way to directly utilize steel slag with extraordinary economic and environmental benefits.