Experiment on preparation of porous glass-ceramics by inorganic gel casting from coal-based slag

•Coal-based slag utilized to produce porous glass-ceramics for resource utilization.•Inorganic gel casting was used as preparation method for porous glass-ceramics.•Orthogonal testing discerned optimal parameter combination for porous glass-ceramics.•The mass ratio of raw materials is the primary factor influencing the properties.•The optimal properties are porosity of 39.62% and compressive strength of 7.57 MPa.