Effect of compositions and additives content on crystallization behavior of Ti-rich phase from Ti-bearing blast furnace slag

The precipitation behavior of Ti-rich phases from high Ti-bearing blast furnace (Ti-BF) slag was studied with (Mg+Al)/(Ca+Si) ratio and B2O3 concentration range from 0.37 to 0.67 and from 0 to 4%, respectively. Scanning Electron Microscope (SEM) and Electron probe X-ray microanalysis (EPMA) were used for determining crystal behavior of the slags quenched from high temperatures and the compositions of the crystals. The results showed that two main phases, which were perovskite and anosovite can precipitate during the experimental process. Specifically speaking, when the content of B2O3 was 2.0% and (Mg+Al)/(Ca+Si) ratio was 0.47, the precipitated crystals of the melt slags transformed from perovskite to anosovite at the temperature of 1320 degrees C. With the increase of B2O3 content from 0 to 4.0%, the volume fraction of anosovite enhanced from 0 to 8.3% correspondingly. The increasing of (Mg+Al)/(Ca+Si) ratio and B2O3 were favorable to form anosovite while decrease (Mg+Al)/(Ca+Si) ratio was beneficial to precipitate perovskite.