Microwave drying method investigation for the process and kinetics of drying characteristics of high-grade rutile TiO2

Titanium dioxide has been extensively applied in aviation, cosmetics, the chemical industry, and coatings. Currently, the primary way to prepare high-grade rutile TiO2 is the chlorination method, which mainly uses ilmenite or titanium slag as raw material through the chlorination process and then reacts it in an oxidation furnace to prepare titanium powders. However, the TiO2 material produced by the liquid-phase method contains a large amount of water, which makes the equipment vulnerable to corrosion in the subsequent process. Meanwhile, the sharp temperature change will lead to the accumulation of water vapor, which may lead to explosion and severe agglomeration, resulting in high research costs and reduced product performance. There-fore, drying equipment with high drying efficiency, high product quality, and low carbon is urgently needed. This paper used microwave drying equipment to assist in drying rutile TiO2 powders. Results indicated that the microwave power, moisture content, and initial mass positively related to the drying rate. The drying process was simulated and analyzed using four common thin-layer kinetic models. A good agreement was that the Modified Page model was in good agreement with the actual drying process of TiO2. The effective diffusion coefficient was calculated. After calculation, the activation energy of microwave-drying TiO2 was 8.22 g/W. This article offers a kinetic theoretical basis and abundant data guidelines for actual products to reinforce the drying of high-grade TiO2 powders.