中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 30 No. 6 June 2020 |
（1. Department of Metallurgical Engineering, College of Materials and Metallurgy, Guizhou University, Guiyang 550025, China;
2. Guizhou Province Key Laboratory of Metallurgical Engineering and Process Energy Saving, Guiyang 550025, China）
Abstract:Low-grade high-sulfur bauxite was pretreated via suspension roasting and muffle furnace roasting to remove sulfur and enhance digestion properties. The results show that sulfur can be efficiently removed, and the alumina digestion properties are significantly improved after suspension roasting. Under optimal conditions (t=70 min, T=280 °C, w(CaO)=8% and Nk=245 g/L), the digestion ratios are 94.45% and 92.08% for the suspension-roasted and muffle-roasted ore, respectively, and the apparent activation energies are 63.26 and 64.24 kJ/mol, respectively. Two crystal models were established by Materials Studio based on the XRD patterns. The DFT simulation shows that the existing Al—O bands after suspension roasting can improve alumina digestion. The (104) and (113) planes of Al2O3 after suspension roasting are found to combine with NaOH more easily than those of Al2O3 treated in a muffle furnace.
Key words: high-sulfur bauxite; suspension roasting; reaction kinetics; digestion mechanism; crystal structure; computer simulation
