Role of minerals properties on leaching process of weathered crust elution-deposited rare earth ore

• Published in: Journal of rare earths Vol. 33; no. 5; pp. 545 - 552
• Main Author: 肖燕飞 刘向生 冯宗玉 黄小卫 黄莉 陈迎迎 吴文远
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2015
• Subjects: Crusts; elution-deposited; granitic; Leaching; Magnesium; Mathematical models; Minerals; Ores; Rare earth metals; rare earths; Rock; volcanic; 傅立叶变换红外光谱; 沉积; 洗脱; 浸出过程; 矿物性质; 稀土矿区; 风化壳; （NH4）2SO4; granitic; elution-deposited; leaching; volcanic; rare earths
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/s1002-0721(14)60454-3

Granite belonged to intrusive rock and volcanic was extrusive rock. There may be many differences in their degree of weathering and mineral chemical composition. The present study investigated the minerals properties and the leaching mechanism of the granitic weathered crust elution-deposited rare earth ore from Longnan Rare Earth Mine area （LN ores） and volcanic weathered crust elution-deposited rare earth ore from Liutang Rare Earth Mine area （LT ores）. The X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FT-IR） were used to characterize the phase of rare earth ores. The particle size distributions and main composition of the ore were also presented in this paper. The leaching mechanisms of two kinds of rare earth ores were analyzed with different kinetics models and could be described by the shrinking-core model. They were all inner diffusion-controlled leaching processes. The leaching equation of the kinetics of the LN ores could be expressed as：4 LN LN 1.096 10 2/3 0.377 8.314 0 2 3=0.1061 （1 ） Tr e tη η×？？？ ？ ？, leaching equation of kinetics of LT ores was 3 LT LT 4.640 10 2/3 0.411 8.314 0 32 3=8.33 101 （1 ） Tr e tη η×？？ ？×？ ？ ？. The rare earth leaching rate of LT ores was always lower in the same condition, and it would need more time and more （NH4）2SO4 consump-tion to achieve the same rare earth leaching efficiency, which would lead to more serious ammonia-nitrogen pollution. Therefore, magnesium salt was proposed as the leaching agent to eliminate ammonia-nitrogen pollution and further studies would be taken in the future.