Performance analysis of coagulation hardening effect of geopolymer prepared from high calcium-based ladle furnace slag

Abstract

With the increasing demand for specialty and high-quality steel, ladle furnace refining technology has been widely used, which produces a large amount of ladle furnace slag (LFS). LFS has problems such as poor stability and early setting, which largely limit the utilization of LFS in the cement industry. In this study, the carbonization technique was used to improve the above-mentioned problems of LFS and to establish the relationship between macro performance and microstructural characteristics. In addition, the setting time, high-temperature resistance, and chemical resistance of the original LFS-based geopolymer (OLFGP) and carbonated LFS-based geopolymer (CLFGP) were compared. The results showed that the structure of LFS was denser after carbonation, and the carbonation products were mainly calcite. The compressive strength of CLFGP was significantly higher than that of OLFGP, reaching 22.6 MPa at 28 days. The initial and final setting times of CLFGP were prolonged by 15 min and 20 min, respectively, compared with OLFGP. In addition, CLFGP exhibited superior chemical resistance. The high-temperature resistance test showed that below 400 ℃ contributed to the development of mechanical properties of LFS-based geopolymer. The problems of poor stability and early setting of LFS were alleviated after carbonation, and the properties of the products were improved, which can be considered as a substitute for cement in the future.