(249g) Mechanistic Understanding of the Mechanical-Activation Enhancement for TiO2 Production Via Acidolysis of Ilmenite Conference: AIChE Annual MeetingYear: 2015Proceeding: 2015 AIChE Annual MeetingGroup: Process Development DivisionSession: Poster Session: Innovations in Process Development Time: Monday, November 9, 2015 - 6:00pm-8:00pm Authors: Wang, X., Sichuan University Yuan, S., Sichuan University Liu, C., Sichuan University Tang, S., East China University of Science and Technology Yue, H., Sichuan University Li, C., Sichuan University Liang, B., Sichuan University Abstract The current sulphate process for TiO2 production via ilmenite is vigorously digested with concentrated sulfuric acid, which discharges considerable dilute sulphuric acid waste in industry. This paper describes recent developments of a mechanical-activation process for the intensification of the ilmenite leaching using dilute sulphuric acid (e.g., concentration of 60 wt.%). The used sulphuric acid can be mixed with waste acid and recycled into the leaching process. The unactivated and mechanically activated ilmenites were carefully characterized by using X-ray diffraction, particle size analysis, BET surface area and scanning electron microscope techniques for the understanding the structural changes during the mechanical activation process. The results revealed that mechano-chemical activation significantly affected on the lattice deformation, crystal size specific surface area and the granule size in mechanical activation systems, which led to a significant increase of leaching rate (from 36% to ~73%). The wet milling was found to be more effective than dry milling due to surface regions with larger lattice strain, significantly larger surface area, and more smaller size crystallites. Moreover, the reaction principles of the mechanically activation were discussed and a possible mechanism was proposed. This methodology is economically and scientifically significant for energy-saving and intensifying the leaching process, which could be widely used in solid-liquid reactions. Keywords:Titanium; Mechanical activation; Sulphuric acid leaching; Wet milling References 1. Li C, Liang B, Guo L. Dissolution of mechanically activated Panzhihua ilmenites in dilute solutions of sulphuric acid. Hydrometallurgy. 2007;89(1-2):1-10. 2. Liang B, Li C, Zhang C, Zhang Y. Leaching kinetics of Panzhihua ilmenite in sulfuric acid. Hydrometallurgy. 2005;76(3-4):173-179. 3. Li C, Liang B, Guo L, Wu Z. Effect of mechanical activation on the dissolution of Panzhihua ilmenite. Minerals Engineering. 2006;19(14):1430-1438. 4. Li C, Liang B, Guo L. Dissolution of mechanically activated Panzhihua ilmenites in dilute solutions of sulphuric acid. Hydrometallurgy. 2007;89(1):1-10. 5. Bin L, Chun L. A New Sulfuric Acid Recycle Routine in TiO2 Pigment Production. AIChE 2013 Annual meeting conference proceedings. 6. Jia L, Liang B, Lü L, et al. Beneficiation of titania by sulfuric acid pressure leaching of Panzhihua ilmenite. Hydrometallurgy. 2014;150:92-98. 7. Welham NJ. Mechanical enhancement of the dissolution of ilmenite. Minerals Engineering. 1998;17(9):827-841. 8. Chen Y, Williams J, Campbell S, Wang G. Increased dissolution of ilmenite induced by high-energy ball milling. Materials Science and Engineering: A. 1999;271(1):485-490. 9. Sasikumar C, Rao D, Srikanth S, Mukhopadhyay N, Mehrotra S. Dissolution studies of mechanically activated Manavalakurichi ilmenite with HCl and H2SO4. Hydrometallurgy. 2007;88(1):154-169.