Preparation and Properties of Foamed Cement for Lightweight Thermal Insulation with Ti-Extraction Blast Furnace Slag and Sulfoaluminate Cement by Chemical Foaming

Abstract

Ti-extraction blast furnace slag (TEBFS) is a chlorine-containing solid waste produced by the metallurgical industry in China. The accumulation of TEBFS is harmful to the environment and the sustainable development of industry. Herein, foamed cement was prepared as a load-bearing and insulation material using TEBFS and sulfoaluminate cement (SAC) by chemical foaming. The effects of TEBFS content, H 2 O 2 content, and calcium stearate content on the bulk density, compressive strength, thermal conductivity, pore structure, and microstructure of the samples were explored. The results show that a stable foam system was obtained by mixing 20–40% TEBFS with SAC, and the most influential factor on the material properties of the samples was H 2 O 2 content. Based on an orthogonal experiment, it was determined that the optimal foamed cement was produced with 40% TEBFS, 1% H 2 O 2 , and 1% calcium stearate. The bulk density, 28-day compressive strength, and thermal conductivity of this sample were 0.68 g/cm 3 , 1.86 MPa, and 0.17 W/(m·K), respectively. The main phases generated in this sample were ettringite, calcium silicate hydrate (C-H-S), and Friedel salt. This study offers a feasible strategy for recycling TEBFS, providing new benefits in the fields of waste management and green building materials.

Keywords: Ti-extraction blast furnace slag, Sulphoaluminate cement, Foamed cement, Properties, recycling