Investigation on the decomposition of titanium slag using sodium carbonate for preparing rutile TiO2

This paper aims to provide fundamental knowledge to prepare rutile TiO2 from titanium slag (71.66% of TiO2, 7.70% of Total Fe) with the assistance of sodium carbonate roasting and microwave heating. The decomposition behaviors of the as-received titanium slag were investigated with experimental comparing groups, namely one group using conventional heating technique and another group using microwave heating technique, respectively. To understand the fundamental knowledge on the decomposition behaviour of titanium slag, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and laser particle size analyzer (LPS) were responsible for the evaluating of the products. Additionally, the influence of sodium carbonate on the phase transformation process was studied. The results indicate that the insoluble Na2Fe2Ti6O16 phase was detected in the conventional roasted product with a low Na2CO3/slag ratio, while this phenomenon was absent in the microwave roasted product. With the increasing amounts of Na2CO3, the particles of the final produced TiO2 have a transformation from irregular shape to rod-like shape. Compared to the products produced by conventional heating techniques, the rod size of the products using the microwave heating technique is more refined. The noticed structure indicated that the microwave heating technique improves the crystallinity growth at a lower Na2CO3/slag ratio. The FT-IR results revealed that products' adsorption ability was enhanced with an increase in Na2CO3/slag ratio and the application of microwave heating techniques. The LPS exhibited that the increase of Na2CO3/slag ratio restrained the particle size of rutile TiO2, which was more evident for the microwave roasted product.