Phase transition of bastnaesite concentrate in calcification process

• Published in: Rare metals 2016-08, Vol.35 (8), p.649-654
• Main Authors: Huang, Yu-Kun, Zhang, Ting-An, Dou, Zhi-He, Liu, Jiang, Tang, Fang-Fang
• Format: Article
• Language: English
• Subjects: Bastnasite; Biomaterials; Calcification; Chemistry and Materials Science; Decomposition; Diffraction; DSC分析; Energy; Environmental protection; Hydrates; Hydrochloric acid; Leaching; Materials Engineering; Materials Science; Metallic Materials; Metallurgy; Morphology; Nanoscale Science and Technology; Ores; Oxyfluorides; Phase transformations; Phase transitions; Physical Chemistry; Rare earth metals; X-ray diffraction; X-射线衍射; 差示扫描量热法; 氟碳铈矿; 氟碳铈精矿; 温度范围; 相变; 钙化
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-016-0756-x

The phase transformation in calcification process was investigated by X-ray diffraction （XRD） and differential scanning calorimeter （DSC）, and the effect of calcification on the leaching rate of rare earth was analyzed. The results show that bastnaesite transforms into rare earth hydrate at the cal- cification temperature range of 225-300 ℃. However, this transition is verified to be an efficient reaction for the acti- vating bastnaesite when the temperature is higher than 200 ℃. The leaching rate of rare earth increases to 89.17 % for activating bastnaesite from 36.27 % for the bastnaesite, and it is the highest with calcification temperature of 250 ℃, which is consistent with the result of DSC analysis. The transition of rare earth oxyfluoride into RE（OH）3 is acceler- ated by the addition of NaOH according to the experiments of different calcification systems.