Optimization of Preparation Process and Property Study of BFS-based Alkali-activated Porous Thermal Insulation Materials

This research centers on the conversion of blast furnace slag, a major by-product of steel-making, into high-performance alkali-activated porous thermal insulation materials. Single-factor experiments explored the effects of water-cement ratio, SS modulus, and alkali activator content on BFS-based cementitious materials, and SDS content, H₂O₂ content, stirring time, and speed on BFS-based thermal insulation materials. An L9(3³) orthogonal experimental design was employed to identify the optimal formulation for BFS-based cementitious composites, while a Box-Behnken Design (BBD) approach was utilized to elucidate the synergistic interactions among the foaming agent-to-foam stabilizer ratio, stirring speed, and stirring time, with respect to thermal conductivity, compressive strength, and apparent density of the insulation materials. The experimental outcomes demonstrated that a water-to-cement ratio of 0.40, an SS modulus of 1.6, and an alkali activator content of 32% culminated in a maximum compressive strength of 45 MPa for the cementitious matrix. For the thermal insulation materials, an SDS concentration of 0.60%, an H₂O₂ dosage of 6%, a stirring duration of 7 min, and an agitation speed of 1000 rpm yielded optimal performance, characterized by a thermal conductivity of 0.058 W/(m·K), a compressive strength of 0.15 MPa, and an apparent density of 245.27 kg/m³. This research offers valuable insights for the efficient utilization of BFS and the production of high-performance thermal insulation materials.