ISSN: 1003-6326
CN: 43-1239/TG

Vol. 26    No. 6    June 2016

Recovery of titanium from undissolved residue (tionite) in titanium oxide industry via NaOH hydrothermal conversion and H2SO4 leaching
Fan-cheng MENG1,2,3, Tian-yan XUE1,2, Ya-hui LIU1,2, Guo-zhi ZHANG1,2,3, Tao QI1,2
(1. National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
2. Key Laboratory of Green Process and Engineering, Institute of Process Engineering,
Chinese Academy of Sciences, Beijing 100190, China;
3. University of Chinese Academy of Sciences, Beijing 100049, China
Abstract: To recover titanium from tionite, a new process consisting of NaOH hydrothermal conversion, water washing, and H2SO4 leaching for TiO2 preparation was developed. The experimental results show that under the optimum hydrothermal conversion conditions, i.e., 50% NaOH (mass fraction) solution, NaOH/tionite mass ratio of 4:1, reaction temperature of 240 °C, reaction time of 1 h and oxygen partial pressure of 0.25 MPa, the titanium was mainly converted into Na2TiO3, and the conversion was 97.2%. The unwanted product Na2TiSiO5 remained stable in water washing, and its formation was prevented by improving NaOH concentration. In water washing process, about 97.6% of Na+ could be recycled by washing the hydrothermal product. The NaOH solutions could be reused after concentration. 96.7% of titanium in the washed product was easily leached in H2SO4 solution at low temperatures, forming titanyl sulfate solution to further prepare TiO2.
Key words: tionite; titanium recovery; NaOH hydrothermal conversion; water washing; H2SO4 leaching
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
Managed by Central South University (CSU)