Evolution Behavior of the Titanium-Bearing Phase During the Low-Temperature Fluidized Chlorination Process of Carbonized Slag Based on Microstructure Image Analysis

This study comprehensively analyzed the evolution behavior of titanium-bearing phases in carbonized slag during the low-temperature fluidized chlorination process using XRD, SEM-EDS, MLA, and other instruments. The XRD analysis shows that the TiC0.70O0.30 phase is the only crystallization phase present in both titanium-bearing carbonized slag (TiBCS) and titanium extraction tailings (TiET). The intensity of the diffraction peak of this phase is significantly lower in TiET than in TiBCS. The SEM-EDS and MLA indicate that melilite is the main phase in TiBCS and TiET, accounting for 79.16% and 78.13%, respectively. Melilite is composed of a composite of elements, such as Ca, Mg, Si, Al, Ti, and O. The phase remained largely unchanged before and after the chlorination reaction. The TiCxOy and metallic iron content in TiET are significantly lower than in TiBCS. The values decreased from 17.19% and 3.65% to 7.38% and 1.31%, respectively. The main reason affecting the chlorination rate of TiC/TiCxOy and metallic iron is that they are enveloped by dense melilite. Another significant feature of TiET is the presence of numerous Cl-bearing holes of a similar size to TiCxOy. These holes are formed in situ by the chlorination reaction of TiCxOy. The results of this study will provide a clearer understanding for research and industrial production based on the low-temperature chlorination reaction of TiBCS. The results can also provide a reference for optimizing the chlorination reaction process and for improving the efficiency of titanium extraction.