Co-modification and crystalline-control of Ti-bearing blast furnace slags

Abstract

The present paper investigated how the SiO2 and B2O3 additions influenced the crystallization behaviors of Ti-bearing blast furnace (Ti-BF) slags with a purpose of recycling the titanium. Ti-BF slags were co-modified by different SiO2 and B2O3 contents. Isothermal experiments were carried out using a Single Hot Thermocouple Technique (SHTT) to in-situ determine the crystal formation, and accordingly Time Temperature Transformation (TTT) curves were established. The results showed that the small amount of B2O3 addition can efficiently promote the transformation of primary crystalline phase from perovskite to rutile, whereas the precipitation of perovskite was suppressed. The kinetics of precipitation of the crystalline phase was explored and the results indicated that the growth of rod shape rutile was 1-D with the ratecontrolling step of interfacial reaction; whereas the precipitated perovskite presented a 3-D growth style. With the increase of holding time, the nucleation rate of the formed crystals including rutile and perovskite became smaller.